Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 02-2012 trié par par titre, page: 0 |
| » 1.5-V-Operation Ultralow Power Circuit of Poly-Si TFTs Fabricated Using the NAOS Method |
Résumé:
We have fabricated thin-film transistors (TFTs) and liquid-crystal displays (LCDs) with monolithic drivers on glass substrates and achieved ultralow power consumption by operating with a low power-supply voltage at 3 V. The gate insulator of the TFTs has a stack structure with an ultrathin interfacial  layer formed by nitric acid oxidation of silicon and a 40-nm-thick  layer formed by plasma-enhanced chemical vapor deposition. Owing to the TFTs with the thin gate insulator, the driving circuits of the LCDs can be operated at a supply voltage of 1.5 V, which is much lower than that of conventional LCDs of 10–15 V. |
| Auteurs: Kubota, Y.;Matsumoto, T.;Tsuji, H.;Suzuki, N.;Imai, S.;Kobayashi, H.; |
| Apparue dans: IEEE Transactions on Electron Devices |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 385 - 392 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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» 2.7-  Single-Frequency  Low-Threshold Sb-Based Diode-Pumped External-Cavity VCSEL |
Résumé:
We present the design, technology, and performances of a tunable Sb-based diode-pumped type-I quantum-well (QW) vertical-external-cavity surface-emitting lasers emitting at 2.7  . The half vertical-cavity surface-emitting laser (VCSEL) structure was grown by molecular beam epitaxy with quantum-well growth temperature of 440  . The sample was thermally annealed to optimize the QW gain design. We report on room-temperature continuous-wave laser with 0.17-mW output power and low threshold incident pump intensity of 0.7 kW/  while pumping at 830 nm with a commercial diode laser. The external cavity provides a circular  beam with a low divergence of 3.6  . The short mm-long optical cavity laser exhibits tunable single frequency operation, with a sidemode suppression ratio  , a linewidth  , and a linear light polarization. Thermal and optical properties are studied. |
| Auteurs: Laurain, A.;Cerutti, L.;Myara, M.;Garnache, A.; |
| Apparue dans: IEEE Photonics Technology Letters |
| Date publication: 02.-2012, volume: 24, issue:4, pages: 246 - 248 |
| Editeur: IEEE |
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| » 2011 IEEE Conference on Computational Intelligence and Games [Conference Reports] |
Résumé:
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| Auteurs: Kim, K.-J.;Cho, S.-B.; |
| Apparue dans: IEEE Computational Intelligence Magazine |
| Date publication: 02.-2012, volume: 7, issue:1, pages: 15 - 18 |
| Editeur: IEEE |
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| » 2011 IEEE Congress on Evolutionary Computation [Conference Reports] |
Résumé:
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| Auteurs: Smith, A.A.; |
| Apparue dans: IEEE Computational Intelligence Magazine |
| Date publication: 02.-2012, volume: 7, issue:1, pages: 12 - 13 |
| Editeur: IEEE |
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| » 2011 International Joint Conference on Neural Networks (IJCNN 2011) [Conference Reports] |
Résumé:
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| Auteurs: Minai, A.A.A.A.; |
| Apparue dans: IEEE Computational Intelligence Magazine |
| Date publication: 02.-2012, volume: 7, issue:1, pages: 13 - 15 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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| » 2012 BizTech Trends and Guidance |
Résumé:
This list of the "2011 top 10 biztech trends" will provide guidance to business and technology executives to help them develop a high-level, long-term approach for exploiting opportunities to help the business grow. |
| Auteurs: Costello, Tom; |
| Apparue dans: IT Professional |
| Date publication: 02.-2012, volume: 14, issue:1, pages: 64 - 63 |
| Editeur: IEEE |
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| » 3-D Finite Element Analysis of Additional Eddy Current Losses in Induction Motors |
Résumé:
In this paper, an approach based on the three-dimensional finite element analysis is proposed to evaluate additional eddy current losses in induction motors of several MW. Losses produced by induced eddy currents in the end-region of the machine (stator clamping-plates and clamping-fingers) and losses provoked by parasitic leakage fields in the housing and in the metal parts of the cooling-ducts are investigated. Furthermore, excess rotor copper losses produced by higher harmonic fields in the rotor squirrel cage are taken into consideration as well. Comprehensive three-dimensional finite element models have been prepared in order to take these effects precisely into account. A numerical procedure based on nonconforming finite element meshes has been used in order to simplify the modeling procedure and the solving process has been carried out in the frequency domain with the aim of reducing the computational time. |
| Auteurs: Stermecki, A.;Biro, O.;Bakhsh, I.;Rainer, S.;Ofner, G.;Ingruber, R.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 959 - 962 |
| Editeur: IEEE |
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| » 3-D Finite Element Modeling and Validation of Power Frequency Multishielding Effect |
Résumé:
The electromagnetic (EM) barrier, the magnetic (M) shunt and a combination of both are widely used in electrical devices in order to control stray fields and effectively reduce the power loss that may lead to hazardous local overheating. This paper focuses on the 3-D finite element modeling and validation of multishielding at power frequencies. The hybrid (M+EM) shielding behavior of the current magnetic shunt configuration is numerically and experimentally examined and is compared to other types. The leakage flux complementary-based measurement method of stray-field loss is also proposed and verified based on the benchmark shielding models. |
| Auteurs: Cheng, Z.;Takahashi, N.;Forghani, B.;Liu, L.;Fan, Y.;Liu, T.;Zhang, J.;Wang, X.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 243 - 246 |
| Editeur: IEEE |
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| » 3-D Integration of Robot Vision and Laser Data With Semiautomatic Calibration in Augmented Reality Stereoscopic Visual Interface |
Résumé:
This paper proposes an augmented reality visualization interface to simultaneously present visual and laser sensors information further enhanced by stereoscopic viewing and 3-D graphics. The use of graphic elements is proposed to represent laser measurements that are aligned to video information in 3-D space. This methodology enables an operator to intuitively comprehend scene layout and proximity information and so to respond in an accurate and timely manner. The use of graphic elements to assist teleoperation, sometime discussed in the literature, is here proposed following an innovative approach that aligns virtual and real objects in 3-D space and color them suitably to facilitate comprehension of objects proximity during navigation. This paper is developed based on authors' previous experience on stereoscopic teleoperation. The approach is experimented on a real telerobotic system, where a user operates a mobile robot located several kilometers apart. The result showed simplicity and effectiveness of the proposed approach. |
| Auteurs: Livatino, S.;Banno, F.;Muscato, G.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 69 - 77 |
| Editeur: IEEE |
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| » 3-D Magnetic Scalar Potential Finite Element Formulation for Conducting Shells Coupled With an External Circuit |
Résumé:
This paper presents a 3-D finite element formulation for a skin depth-independent shell element. With this formulation, thin conducting shells, which are multiply connected (i.e., having holes), and which can be coupled with an external circuit, can be modeled. This formulation takes into account the field variation through the depth due to skin effect. First, the method is described. Next, three numerical examples, including an automotive example, are presented. |
| Auteurs: Guerin, C.;Meunier, G.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 323 - 326 |
| Editeur: IEEE |
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| » 3-D Model-Based Multiple-Object Video Tracking for Treatment Room Supervision |
Résumé:
We present a method to monitor a patient and the equipment in a radiotherapy treatment room, by exploiting the information in the treatment plan, enriched with other elements such as visual, geometric, and “semantic” information. Using all these information items, and a generic model, a virtual environment of the scene is created, with maximum precision. The images resulting from video sequences with several cameras are also used to confront the filmed information on the scene and its numerical representation. The method is based on the features of the scene elements, and on a fuzzy formalism. The feasibility of the method is being quantitatively evaluated in the absence of treatment, to be further exploited in a module for external control by video in real conditions. |
| Auteurs: Portela Sotelo, M. A.;Desseree, E.;Moreau, J-.M.;Shariat, B.;Beuve, M.; |
| Apparue dans: IEEE Transactions on Biomedical Engineering |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 562 - 570 |
| Editeur: IEEE |
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| » 3-D Posture and Gesture Recognition for Interactivity in Smart Spaces |
Résumé:
Automatic perception of human posture and gesture from vision input has an important role in developing intelligent video systems. In this paper, we present a novel gesture recognition approach for human computer interactivity based on marker-less upper body pose tracking in 3-D with multiple cameras. To achieve the robustness and real-time performance required for practical applications, the idea is to break the exponentially large search problem of upper body pose into two steps: first, the 3-D movements of upper body extremities (i.e., head and hands) are tracked. Then using knowledge of upper body model constraints, these extremities movements are used to infer the whole 3-D upper body motion as an inverse kinematics problem. Since the head and hand regions are typically well defined and undergo less occlusion, tracking is more reliable and could enable more robust upper body pose determination. Moreover, by breaking the problem of upper body pose tracking into two steps, the complexity is reduced considerably. Using pose tracking output, the gesture recognition is then done based on longest common subsequence similarity measurement of upper body joint angles dynamics. In our experiment, we provide an extensive validation of the proposed upper body pose tracking from 3-D extremity movement which showed good results with various subjects in different environments. Regarding the gesture recognition based on joint angles dynamics, our experimental evaluation of five subjects doing six upper body gestures with average classification accuracies over 90% indicates the promise and feasibility of the proposed system. |
| Auteurs: Tran, C.;Trivedi, M. M.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 178 - 187 |
| Editeur: IEEE |
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| » 40-Gb/s NRZ-to-RZ and OOK-to-BPSK Format and Wavelength Conversion on a Single SOA-MZI for Gridless Networking Operations |
Résumé:
We propose and experimentally demonstrate simultaneous format and wavelength conversion at 40 Gb/s exploiting a single commercial semiconductor optical amplifier Mach–Zehnder interferometer. Conversion from nonreturn-to-zero (NRZ) to a 2-ps return-to-zero (RZ) on-off keying (OOK) format suitable for grooming onto a 160-Gb/s optical time-division-multiplexing frame is achieved. Furthermore, for the first time to the best of our knowledge, 40-Gb/s conversion from RZ OOK to RZ binary phase-shift keying (BPSK) is achieved. The effectiveness of the proposed scheme is demonstrated by means of bit-error-rate measurements. Error-free operations are reported, with a power penalty of 0.5 dB for the case of NRZ-to-RZ OOK conversion and of 3 dB (comprehensive of the degradation due to the wavelength conversion used to generate the probe signal) for the case of OOK-to-BPSK conversion. |
| Auteurs: Fresi, F.;Scaffardi, M.;Amaya, N.;Nejabati, R.;Simeonidou, D.;Bogoni, A.; |
| Apparue dans: IEEE Photonics Technology Letters |
| Date publication: 02.-2012, volume: 24, issue:4, pages: 279 - 281 |
| Editeur: IEEE |
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| » 50-Gb/s Silicon Optical Modulator |
Résumé:
Optical modulators formed in silicon are the keystone to many low cost optical applications. Increasing the data rate of the modulator benefits the efficiency of channel usage and decreases power consumption per bit of data. Silicon-based modulators which operate via carrier depletion have to the present been demonstrated at data rates up to 40 Gb/s; however, here we present for the first time optical modulation at 50 Gb/s with a 3.1-dB extinction ratio obtained from carrier depletion based phase shifter incorporated in a Mach–Zehnder interferometer. A corresponding optical insertion loss of approximately 7.4 dB is measured. |
| Auteurs: Thomson, D. J.;Gardes, F. Y.;Fedeli, J.-M.;Zlatanovic, S.;Hu, Y.;Kuo, B. P. P.;Myslivets, E.;Alic, N.;Radic, S.;Mashanovich, G. Z.;Reed, G. T.; |
| Apparue dans: IEEE Photonics Technology Letters |
| Date publication: 02.-2012, volume: 24, issue:4, pages: 234 - 236 |
| Editeur: IEEE |
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» 7-Tb/s ) Signal Transmission Over 320 km Using PDM-64QAM Modulation |
Résumé:
We have transmitted a  signal over 320-km conventional single mode fiber (SMF-28) with hybrid amplifier spans of 80 km. Each terabit superchannel comprises ten Nyquist wavelength division multiplexing polarization division multiplexing 64 quadrature amplitude modulation subchannels occupying 137.5 GHz, which gives a spectral-efficiency of 7.65 b/s/Hz per superchannel. The bit error ratio of all channels after transmission over 320 km is measured smaller than  , the soft-decision forward error correction limit. |
| Auteurs: Yu, J.;Dong, Z.;Chien, H.-C.;Shao, Y.;Chi, N.; |
| Apparue dans: IEEE Photonics Technology Letters |
| Date publication: 02.-2012, volume: 24, issue:4, pages: 264 - 266 |
| Editeur: IEEE |
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»  -Regularized STAP Algorithms With a Generalized Sidelobe Canceler Architecture for Airborne Radar |
Résumé:
In this paper, we propose novel  -regularized space-time adaptive processing (STAP) algorithms with a generalized sidelobe canceler architecture for airborne radar applications. The proposed methods suppose that a number of samples at the output of the blocking process are not needed for sidelobe canceling, which leads to the sparsity of the STAP filter weight vector. The core idea is to impose a sparse regularization ( -norm type) to the minimum variance criterion. By solving this optimization problem, an -regularized recursive least squares ( -based RLS) adaptive algorithm is developed. We also discuss the SINR steady-state performance and the penalty parameter setting of the proposed algorithm. To adaptively set the penalty parameter, two switched schemes are proposed for -based RLS algorithms. The computational complexity analysis shows that the proposed algorithms have the same complexity level as the conventional RLS algorithm ^2))$) , where  is the filter weight vector length), but a significantly lower complexity level than the loaded sample covariance matrix inversion algorithm ^3))$) and the compressive sensing STAP algorithm ( ^3)$) , where  is the angle-Doppler plane size). The simulation results show that the proposed STAP algorithms converge-
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rapidly and provide a SINR improvement using a small number of snapshots. |
| Auteurs: Yang, Z.;de Lamare, R. C.;Li, X.; |
| Apparue dans: IEEE Transactions on Signal Processing |
| Date publication: 02.-2012, volume: 60, issue:2, pages: 674 - 686 |
| Editeur: IEEE |
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»  : A New Physics-Based Explicit Compact Model for Lightly Doped Short-Channel Triple-Gate SOI MOSFETs |
Résumé:
In this paper, we present a new compact drain-current model for double-gate or triple-gate silicon on insulator (SOI) metal–oxide–semiconductor field-effect transistors, which is based on a physics-based 3-D analysis. Explicit analytical model equations for the height of the potential barrier are derived in closed form from a 3-D model for the channel electrostatics without the need to introduce any fitting parameter. The device current is described by a superposition of a surface-channel current above threshold and a center current in the subthreshold region, accounting for the movement of the most leaky path in the device cross section. Comparison with Technology Computer Aided Design (TCAD) shows a good scalability of the model down to a gate length of 30 nm. Furthermore, the  –  characteristics are compared with measurements and obtain accurate results down to an effective channel length of 53 nm. |
| Auteurs: Kloes, A.;Schwarz, M.;Holtij, T.; |
| Apparue dans: IEEE Transactions on Electron Devices |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 349 - 358 |
| Editeur: IEEE |
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»  and  Codoped Tellurite Optical Fiber for Lasers and Amplifiers in the Near-Infrared Wavelength Region: Fabrication, Optical Characterization, and Prospects |
Résumé:
A tellurite optical fiber doped with and ions was designed and fabricated with the aim of assessing its suitability as laser and optical amplifier operating at 1550 nm, compatible with silica fiber standard dimensions. High-quality optical fibers, with an attenuation loss of 1.0 dB/m at 1320 nm, were obtained featuring a 6-  diameter core. A fiber laser emitting at 1550 nm upon pumping at 976 nm and a fiber amplifier characterized by signal amplification of 8 dB for a length of 10 cm were demonstrated. |
| Auteurs: Lousteau, J.;Boetti, N.;Chiasera, A.;Ferrari, M.;Abrate, S.;Scarciglia, G.;Venturello, A.;Milanese, D.; |
| Apparue dans: IEEE Photonics Journal |
| Date publication: 02.-2012, volume: 4, issue:1, pages: 194 - 204 |
| Editeur: IEEE |
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| » A 0.018% THD+N, 88-dB PSRR PWM Class-D Amplifier for Direct Battery Hookup |
Résumé:
A low-distortion third-order class-D amplifier that is fully integrated into a 0.18-  m CMOS process was designed for direct battery hookup in a mobile application. A class-D amplifier for direct battery hookup must have a sufficiently high power supply rejection ratio (PSRR) in preparation for noise, such as when a global system for mobile communications (GSM) bursts ripples through the system power line. This amplifier has a high PSRR of 88 dB for 217-Hz power supply ripples, using a third-order loop filter. System performance and stability are improved by applying the design technique of input-feedforward delta-sigma $) modulators to the pulse-width modulation (PWM) class-D amplifier. A filterless method that can remove the external LC filter is employed, which offers great advantages in terms of PCB space and system cost. This amplifier achieves a power efficiency of 85.5% while delivering an output power of 750 mW into an 8-  load from a 3.7-V supply voltage. Maximum achieved output power at 1% total harmonic distortion plus noise (THD+N) from a 4.9-V supply voltage into an 8- load is 1.15 W. This class-D amplifier is designed to have a broad operational range of 2.7–4.9 V for the direct use of mobile phone battery power. It has a total area of 1.01 mm  and achieves a THD+N of 0.018%. |
| Auteurs: Choi, Y.;Tak, W.;Yoon, Y.;Roh, J.;Kwon, S.;Koh, J.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 454 - 463 |
| Editeur: IEEE |
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| » A 130 nm 1.2 V/3.3 V 16 Kb Spin-Transfer Torque Random Access Memory With Nondestructive Self-Reference Sensing Scheme |
Résumé:
Among all the emerging memories, Spin-Transfer Torque Random Access Memory (STT-RAM) has demonstrated many promising features such as fast access speed, nonvolatility, excellent scalability, and compatibility to CMOS process. However, the large process variations of both magnetic tunneling junction (MTJ) and MOS transistors in the scaled technologies severely limit the yield of STT-RAM chips. In this work, we proposed a new sensing scheme, named as nondestructive self-reference sensing, or NSRS, for STT-RAM. By leveraging the different dependencies of the high and low resistance states of MTJs on the cell current amplitude, the proposed NSRS technique can work well at the scenario when bit-to-bit variation of MTJ resistances is large. Furthermore, we proposed three combined magnetic- and circuit-level techniques, including R-I curve skewing, yield-driven cell current selection, and ratio matching, to further improve the sense margin and robustness of NSRS sensing scheme. The measurement results of a 16 Kb STT-RAM test chip show that our proposed nondestructive self-reference sensing technique can reliably readout all the measured memory bits, of which 10% read failure rate was observed by using the conventional sensing technique. The three enhancement technologies ensure a 20 mV minimum sense margin and the whole sensing process can complete within 15 ns. |
| Auteurs: Chen, Y.;Li, H.;Wang, X.;Zhu, W.;Xu, W.;Zhang, T.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 560 - 573 |
| Editeur: IEEE |
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| » A 2.5 kV Isolation 35 kV/us CMR 250 Mbps Digital Isolator in Standard CMOS With a Small Transformer Driving Technique |
Résumé:
A small-size on-chip transformer-based digital isolator for power control systems is proposed. With a proposed pulse generation and detection scheme that enables a 5 V standard CMOS transistor to utilize GHz-band signals, transformer area is reduced to 1/4–1/8 that of conventional transformers. A test chip achieves a 2.5 kV isolation voltage, a 35 kV/us CMR, a 1.6 mA static current and a 250 Mbps data rate, all which are equal to or superior to those of optocouplers or conventional digital isolators. The developed technology greatly reduces the number of chips in power control systems by allowing integration of multiple isolators in a CMOS chip together with microcontrollers or gate drivers. Moreover, the high-speed low-power capability expands the application potential to include isolated serial links, controller area network (CAN), FlexRay, medical devices, displays, sensors, etc. |
| Auteurs: Kaeriyama, S.;Uchida, S.;Furumiya, M.;Okada, M.;Maeda, T.;Mizuno, M.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 435 - 443 |
| Editeur: IEEE |
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| » A 200-MHz Integrated Buck Converter With Resonant Gate Drivers for an RF Power Amplifier |
Résumé:
High switching frequency dc-dc converters are present in many applications where wide regulation bandwidth and high efficiency are needed. A resonant gate driver is presented for improvement of efficiency at light-to-medium load conditions. Gate power losses that are a main contributor to total losses are reduced thanks to energy recovery. A testchip designed in 0.25- BiCMOS shows as much as a 30% decrease in power losses compared to a conventional driver at 200-MHz switching frequency. The proposed resonant gate driver is fully integrated with its inductor unlike earlier works. The limitation in the reduction of gate losses is detailed and confirmed experimentally. |
| Auteurs: Bathily, M.;Allard, B.;Hasbani, F.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 610 - 613 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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» A 21 nV/  Hz Chopper-Stabilized Multi-Path Current-Feedback Instrumentation Amplifier With 2  V Offset |
Résumé:
This paper describes the design of a precision instrumentation amplifier. It employs chopping to reduce its offset and  noise, and the resulting ripple caused by the up-modulated offset and noise is suppressed by a ripple reduction loop. A multi-path architecture is used to eliminate the transfer function notch that would otherwise be introduced by the ripple reduction loop. The amplifier is implemented in a standard 0.7  CMOS technology and draws 143  current from a 5 V supply. Its input-referred noise is 21 nV/  Hz and its residual offset is less than 2  (12 samples). The instrumentation amplifier can also be configured as a general-purpose opamp with half the noise and offset, but which dissipates the same amount of power. |
| Auteurs: Fan, Q.;Huijsing, J. H.;Makinwa, K. A. A.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 464 - 475 |
| Editeur: IEEE |
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| » A 255 MHz Programmable Gain Amplifier and Low-Pass Filter for Ultra Low Power Impulse-Radio UWB Receivers |
Résumé:
A 90 nm-CMOS power-optimized analog baseband chain for ultra-low-power impulse-radio ultra-wideband (IR-UWB) receivers is presented. The proposed device merges the functions of a programmable gain amplifier (PGA) and a low-pass filter (LPF). It consists of the cascade of three biquadratic cells made up by opamps in a series-shunt configuration, which features high input impedance, low load effects in the cascade blocks, and better frequency response. The opamp parameters are included in the overall biquad transfer function. This allows getting very low power performance, since the opamp bandwidth is not required to be much larger than the filter cutoff frequency. Moreover, the current consumption is optimized according to the selected gain level (1.3 mA at 0 dB-gain up to 1.9 mA at 40 dB-gain). The PGA features a 0–40 dB programmable gain range with a 5 dB gain-step. The LPF performs a sixth-order 255 MHz low-pass frequency response. For the overall chain the IIP3 is 14 dBm at 0 dB gain, while the input referred noise is 12.5 nV/ Hz at 40 dB gain. |
| Auteurs: D'Amico, S.;De Blasi, M.;De Matteis, M.;Baschirotto, A.; |
| Apparue dans: IEEE Transactions on Circuits and Systems I: Regular Papers |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 337 - 345 |
| Editeur: IEEE |
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| » A 667 MHz Logic-Compatible Embedded DRAM Featuring an Asymmetric 2T Gain Cell for High Speed On-Die Caches |
Résumé:
Circuit techniques for enhancing the retention time and random cycle of logic-compatible embedded DRAMs (eDRAMs) are presented. An asymmetric 2T gain cell utilizes the gate and junction leakages of a PMOS write device to maintain a high data ‘1’ voltage level which enables fast read access using an NMOS read device. A current-mode sense amplifier (C-S/A) featuring a cross-coupled PMOS latch and pseudo-PMOS diode pairs is proposed to overcome the innate problem of small read bit-line (RBL) voltage swing in 2T eDRAMs with improved voltage headroom and better impedance matching under process–voltage–temperature (PVT) variations. A half-swing write bit-line (WBL) scheme is adopted to improve the WBL speed by 33% and reduce its power dissipation by 25% during write-back operation with no effect on retention time. A stepped write word-line (WWL) driver reduces the current drawn from the boosted high and low supplies by 67%. A 192 kb eDRAM test chip with 512 cells-per-BL implemented in a 65 nm low-power (LP) CMOS process shows a random cycle frequency and latency of 667 MHz and 1.65 ns, respectively, at 1.1 V and 85  . The measured refresh period at a 99.9% bit yield condition was 110  which is comparable to that of recently published 1T1C eDRAM designs. |
| Auteurs: Chun, K. C.;Jain, P.;Kim, T.-H.;Kim, C. H.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 547 - 559 |
| Editeur: IEEE |
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| » A Bicriteria-Optimization-Approach-Based Dimensionality-Reduction Model for the Color Display of Hyperspectral Images |
Résumé:
This paper proposes a new nonlinear dimensionality-reduction model based on a bicriteria global optimization approach for the color display of hyperspectral images. The proposed fusion model is derived from two well-known and contradictory criteria of good visualization, which are useful in any multidimensional imagery color display, namely, accuracy, with the preservation of spectral distance criterion, and contrast, guaranteeing that colors are well distinguished or concretely allowing the good separability of each observed existing material in the final visualized color image. An internal parameter allows our algorithm to express the contribution or the importance of these two criteria for a specific application. In this framework, which also can be viewed as a classical Bayesian optimization strategy involving a tradeoff between fidelity to the unreduced (raw) spectral data and the expected highly contrasted resulting mapping, we will show that a hybrid optimization strategy, combining a global and deterministic optimization procedure and a local stochastic search using the Metropolis criterion, can be exploited to efficiently minimize the complex nonlinear objective cost function related to our model. The experiments reported in this paper demonstrate that the proposed model, taking into account these two criteria of good visualization, makes easier and more reliable the interpretation and quick overview of such multidimensional hyperspectral images. |
| Auteurs: Mignotte, M.; |
| Apparue dans: IEEE Transactions on Geoscience and Remote Sensing |
| Date publication: 02.-2012, volume: 50, issue:2, pages: 501 - 513 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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| » A Bilinear Approach to the Position Self-Calibration of Multiple Sensors |
Résumé:
This paper presents a novel algorithm for the automatic 3D localization of a set of sensors in an unknown environment. Given the measures of a set of time of arrival delays at each sensor, the approach simultaneously estimates the 3D position of the sensors and the sources that have generated the event. Such inference is obtained with no assumption about the sensor localization; the only assumption made is that the emission time of the sources must be known in order to evaluate the time of flight for each event. Moreover, we propose a further method that deals with the likely case of missing data in the measurements. This occurs when sensors are far apart or behind natural barriers that avoids the registration of the given event. Simulated experiments show the validity of the approach for different setups of sensors and number of events. |
| Auteurs: Crocco, M.;Del Bue, A.;Murino, V.; |
| Apparue dans: IEEE Transactions on Signal Processing |
| Date publication: 02.-2012, volume: 60, issue:2, pages: 660 - 673 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Biomimetic Active Electrolocation Sensor for Detection of Atherosclerotic Lesions in Blood Vessels |
Résumé:
Weakly electric fish sense their surroundings in complete darkness by active electrolocation. In a biomimetic approach, we designed catheter-based technical sensor systems working according to the same biological principles that could be used for medical diagnostics of arteriosclerosis. Several measurements using artificial blood vessels, computer simulations, and a physical test bed showed that it is possible to detect and analyze vulnerable plaques in blood vessels and that our method of signal production and analysis is principally suitable for medical diagnostics. |
| Auteurs: Metzen, M.G.;Biswas, S.;Bousack, H.;Gottwald, M.G.;Mayekar, K.;von der Emde, G.; |
| Apparue dans: IEEE Sensors Journal |
| Date publication: 02.-2012, volume: 12, issue:2, pages: 325 - 331 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Broadband CMOS RF Front-End for Universal Tuners Supporting Multi-Standard Terrestrial and Cable Broadcasts |
Résumé:
A wideband CMOS highly linear and low noise RF front-end including inductor-less wideband LNA, integrated passive tunable filter, harmonic rejection mixer (HRM), and loop-through amplifier (LTA) is proposed for universal tuners. The proposed inductor-less wideband LNA shows a gain range greater than 55 dB with fine gain step less than 0.5 dB while achieving higher linearity and lower noise figure (NF), as compared with the traditional resistive/active feedback LNA through a source follower (SF). The integrated tunable filter covers the entire VHF bands without dividing the frequency range by multiple filters. By adopting tunable filter and HRM simultaneously, the overall harmonic rejection ratio (HRR) of over 65 dBc is obtained. The active feedback LTA utilizing a complementary characteristic of NMOS and PMOS is proposed for supporting multiple tuner applications. The proposed RF front-end achieves a maximum voltage gain of 42 dB, a minimum NF of 4.7 dB, and CTB and CSO of under  60 dBc. The power consumption including the LTA is 144 mW at a 1.8 V supply and the chip area is 1.43 mm  . |
| Auteurs: Im, D.;Kim, H.;Lee, K.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 392 - 406 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Broadband Low-Power Low-Noise Active Balun With Second-Order Distortion Cancellation |
Résumé:
This paper presents a broadband single-ended input differential output low noise amplifier exploiting IM2 cancelling. A linear feedback from the common mode output to the single-ended input effectively cancels the second-order distortion products in the differential output. The feedback path can be designed for minimum noise, leading to equal or lower noise compared to the amplifier without feedback. A replica bias ensures reduced sensitivity to process, supply voltage and temperature variations. The measured IIP2 across the band from 230 MHz to 470 MHz, varies from 19 to 26 dBm when the feedback is disabled and from 28 to 34 dBm when the feedback is enabled. Measured NF is 2.25 dB in the VHF band and between 2 and 4 dB in the UHF band. Power dissipation is 7.8 mW . |
| Auteurs: Manstretta, D.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 407 - 420 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Carrier-Based PWM Strategy With Zero-Sequence Voltage Injection for a Three-Level Neutral-Point-Clamped Converter |
Résumé:
Performance of a carrier-based pulsewidth modulation (CB-PWM) strategy can be improved by the inclusion of a zero-sequence voltage in the modulation-reference signal. This paper proposes a new CB-PWM strategy for a three-level neutral-point-clamped (NPC) converter, which is based on a zero-sequence voltage injection. By inclusion of the zero-sequence voltage, the sinusoidal-modulation reference is modified to 1) carry out the voltage-balancing task of the dc-link capacitors, with no additional control effort, 2) reduce the switching losses, and 3) reduce the low-frequency voltage oscillations of the neutral point. The proposed strategy is an alternative approach to the nearest three-vector (NTV) space-vector modulation (SVM) strategy and is obtained by the analysis of the NTV-SVM strategy and establishing a correlation between the NTV-SVM and the CB-PWM strategies. The salient features of the proposed scheme, as compared with the NTV-SVM strategy, are: 1) its reduced computational processing time which is attractive for digital implementation and 2) its reduced switching losses. Compared with the existing CB-PWM strategies, the proposed strategy offers 1) capability to balance the capacitor voltages and reduce the NP voltage oscillations and 2) reduced switching losses. Performance of the proposed CB-PWM strategy for a three-level NPC converter based on time-domain simulation studies in the MATLAB/SIMULINK environment is evaluated and also experimentally verified. |
| Auteurs: Pou, J.;Zaragoza, J.;Ceballos, S.;Saeedifard, M.;Boroyevich, D.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 642 - 651 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Cell Method Formulation of 3-D Electrothermomechanical Contact Problems With Mortar Discretization |
Résumé:
A 3-D domain decomposition method for fully coupled electrothermomechanical contact problems is presented. The formulation is based on the cell method. Contacting domains are linked together by introducing a new reference frame (i.e., the mortar surface). Field discontinuities across contact interfaces are simulated by suitable constitutive operators. It is shown that the same coupling strategy can be adopted for the electrical, thermal, and mechanical contact problems. Compatibility constraints are imposed by means of dual Lagrange multipliers defined on the mortar surface. Coupled nonlinear algebraic equations are finally cast into a saddle-point problem, which is resolved by combining the Schur complement method with the Newton–Raphson method. The proposed mortar approach is validated with a commercial 3-D finite-element method multiphysics software package. |
| Auteurs: Moro, F.;Alotto, P.;Freschi, F.;Guarnieri, M.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 503 - 506 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Chance-Constrained Two-Stage Stochastic Program for Unit Commitment With Uncertain Wind Power Output |
Résumé:
In this paper, we present a unit commitment problem with uncertain wind power output. The problem is formulated as a chance-constrained two-stage (CCTS) stochastic program. Our model ensures that, with high probability, a large portion of the wind power output at each operating hour will be utilized. The proposed model includes both the two-stage stochastic program and the chance-constrained stochastic program features. These types of problems are challenging and have never been studied together before, even though the algorithms for the two-stage stochastic program and the chance-constrained stochastic program have been recently developed separately. In this paper, a combined sample average approximation (SAA) algorithm is developed to solve the model effectively. The convergence property and the solution validation process of our proposed combined SAA algorithm is discussed and presented in the paper. Finally, computational results indicate that increasing the utilization of wind power output might increase the total power generation cost, and our experiments also verify that the proposed algorithm can solve large-scale power grid optimization problems. |
| Auteurs: Wang, Q.;Guan, Y.;Wang, J.; |
| Apparue dans: IEEE Transactions on Power Systems |
| Date publication: 02.-2012, volume: 27, issue:1, pages: 206 - 215 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Chaotic Approach of Differential Evolution Optimization Applied to Loudspeaker Design Problem |
Résumé:
Over the past few years, the field of global optimization has been very active, producing different kinds of deterministic and stochastic algorithms for optimization in the continuous domain. These days, the use of evolutionary algorithms (EAs) to solve optimization problems is a common practice due to their competitive performance on complex search spaces. EAs are well known for their ability to deal with nonlinear and complex optimization problems. Differential evolution (DE) algorithms are a family of evolutionary optimization techniques that use a rather greedy and less stochastic approach to problem solving, when compared to classical evolutionary algorithms. The main idea is to construct, at each generation, for each element of the population a mutant vector, which is constructed through a specific mutation operation based on adding differences between randomly selected elements of the population to another element. Due to its simple implementation, minimum mathematical processing and good optimization capability, DE has attracted attention. This paper proposes a new approach to solve electromagnetic design problems that combines the DE algorithm with a generator of chaos sequences. This approach is tested on the design of a loudspeaker model with 17 degrees of freedom, for showing its applicability to electromagnetic problems. The results show that the DE algorithm with chaotic sequences presents better, or at least similar, results when compared to the standard DE algorithm and other evolutionary algorithms available in the literature. |
| Auteurs: Coelho, L. S.;Bora, T. C.;Lebensztajn, L.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 751 - 754 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Combined Position and Stator-Resistance Observer for Salient PMSM Drives: Design and Stability Analysis |
Résumé:
A reduced-order position observer with stator-resistance adaptation is proposed for motion-sensorless permanent-magnet synchronous motor drives. A general analytical solution for the stabilizing observer gain and stability conditions for the stator-resistance adaptation are derived. Under these conditions, the local stability of the position and stator-resistance estimation is guaranteed at every operating point except the zero frequency, if other motor parameters are known. Furthermore, the effect of inaccurate model parameters on the local stability of the position estimation is studied, and an observer gain design that makes the observer robust is proposed. The proposed observer is experimentally tested using a 2.2-kW motor drive; stable operation at very low speeds under different loading conditions is demonstrated. |
| Auteurs: Hinkkanen, M.;Tuovinen, T.;Harnefors, L.;Luomi, J.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 601 - 609 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Compact Capacitor-Less High-Speed DRAM Using Field Effect-Controlled Charge Regeneration |
Résumé:
We demonstrate experimentally a capacitor-less one-transistor dynamic random access memory (DRAM) based on fully depleted silicon-on-insulator substrate. In our device, the charges are directly stored in front gate capacitor $) and read out through a fast feedback regeneration process. The simulated read/write times of our device reach below 1 ns, much faster than conventional 1T-1C DRAM. The read/write biasing voltages can be scaled down to 1.1 V, achieving long retention time $) . |
| Auteurs: Wan, J.;Le Royer, C.;Zaslavsky, A.;Cristoloveanu, S.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 179 - 181 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Compact Dynamic-Performance-Improved Current-Steering DAC With Random Rotation-Based Binary-Weighted Selection |
Résumé:
Conventional binary-weighted current-steering DACs are generally operated with current groups where each group is binary-weighted and formed with predetermined members of a unit current-source array. This paper proposes a random rotation-based binary-weighted selection (RRBS) that efficiently performs dynamic-element matching (DEM) by randomly rotating the sequence of these units to form new binary-weighted current groups for each DAC output. Without using binary-to-thermometer decoders, RRBS features its simplicity and compactness of DEM realization. Compared to conventional binary-weighted DACs, RRBS DACs are insensitive to the mismatch of small-size current-sources and exhibit better dynamic performance. A 10-bit RRBS DAC is implemented with only 0.034 mm in a standard 1P6M 1.8 V 0.18 m CMOS process. Measured performance achieves  61 dB spurious-free dynamic range (SFDR) in the Nyquist bandwidth with 500 MS/s, while its active area is less than one-tenth of that required by state-of-the-art 10-bit current steering DACs. To the best of our knowledge, the proposed RRBS implements the smallest area for high-speed current-steering DACs up to now. Its SFDR is also comparable to that of 12-bit published designs. Three popular figures-of-merit (FOMs) are used to compare this design with other state-of-the-art 10–12-bit DACs, with the proposed design performing best with 2 FOMs. |
| Auteurs: Lin, W.-T.;Kuo, T.-H.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 444 - 453 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
» A Comparative Study of NBTI and RTN Amplitude Distributions in High-  Gate Dielectric pMOSFETs |
Résumé:
Random telegraph noise (RTN) and negative bias temperature (NBT) stress-induced threshold voltage $) fluctuations in high-  gate dielectric and metal-gate pMOSFETs are investigated. We measured RTN amplitude distributions before and after NBT stress. RTN in poststressed devices exhibits a broader amplitude distribution than the prestress one. In addition, we trace a single trapped charge-induced  in NBT stress and find that the average  is significantly larger than a caused by RTN. A 3-D atomistic simulation is performed to compare a single-charge-induced by RTN and NBTI. In our simulation, the probability distribution of a NBT trapped charge in the channel is calculated from the reaction-diffusion model. Our simulation confirms that the NBT-induced indeed has a larger distribution tail than RTN due to a current-path percolation effect. |
| Auteurs: Chiu, J. P.;Chung, Y. T.;Wang, T.;Chen, M.-C.;Lu, C. Y.;Yu, K. F.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 176 - 178 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Computationally Efficient Numerical Model of the Offset of CMOS-integrated Vertical Hall Devices |
Résumé:
Highlights? Computationally efficient numerical model to study effects determining the offset of five-contact vertical Hall sensors (VHS) as a function of the input voltage ? Simulation of the junction field effect (JFE) altering the depletion layer width between n-well and p-doped regions as well as resistive asymmetries due to contact shifts ? Linear offset component are modeled adequately by resistive imbalances caused by lateral contact shifts in the nanometer range, whereas the JFE is responsible for the nonlinear effects of dominantly quadratic dependence of the offset voltage on the input voltage ? Both effects contribute additively to the overall offset ? Experimentally obtained offsets using CMOS-based VHS can be adequately described by the simulation results |
| Auteurs: This paper describes a computationally efficient numerical model to study effects determining the offset of five-contact vertical Hall sensors (VHS). It applies a two-dimensional finite element model implemented in COMSOL Multiphysics and allows to t |
| Apparue dans: Sensors and Actuators A: Physical |
| Date publication: 02.-2012 |
| Editeur: Elsevier B.V. |
| Document complet vers site de l'éditeur |
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|
| » A Concave FE-BI-MLFMA for Scattering by a Large Body With Nonuniform Deep Cavities |
Résumé:
A concave finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) is presented for scattering by a large body with nonuniform deep cavities. Different from the conventional FE-BI-MLFMA, the boundary integral equation in this concave FE-BI-MLFMA is established on a concave surface to reduce the region of the finite element method (FEM), which can significantly reduce the dispersion error from the FEM and improve the efficiency of FE-BI-MLFMA especially for nonuniform cavities. To eliminate the problem of slow convergence caused by concave surface, an efficient preconditioner based on the sparse approximate inverse (SAI) is constructed in this paper. Numerical performance of the constructed preconditioner based on the SAI is investigated in detail. Numerical experiments demonstrate the accuracy and efficiency of this SAI preconditioned concave FE-BI-MLFMA for nonuniform deep and large cavites. This SAI preconditioned concave FE-BI-MLFMA is parallelized to further improve its capability in this paper. An extremely big and deep nonuniform cavity has been calculated, demonstrating the great capability of this parallel concave FE-BI-MLFMA. |
| Auteurs: Yang, M.-L.;Sheng, X.-Q.;Pan, X.-M.;Pi, W.-C.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 687 - 690 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Convenient Mesh Rotation Method of Finite Element Analysis Using Sub-Matrix Transformation Approach |
Résumé:
This paper presents a novel sub-matrix transformation method on mesh rotation problems in the finite element analysis (FEA) of electric machines. This proposed approach is simple, convenient and readily implementable. For each rotor position, only the transformation matrix which has fixed regular pattern versus the rotor position displacement needs to be modified. Transformation matrices with first-order element, second-order element as well as with periodic and anti-periodic boundary conditions have been developed. By using sub-matrix transformation, the mesh coupling can be realized automatically, efficiently and with minimal computing burden, since all the coefficients of the FEA system equation are stored in the sub-matrixes and they do not need to be re-assembled for different rotor positions. Formulae derivation and theoretical analysis are presented together simulation results to verify the validity of proposed method. |
| Auteurs: Niu, S.;Ho, S. L.;Fu, W. N.;Zhu, J.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 303 - 306 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Cooperative User-System Approach for Optimizing Performance in Content Distribution/Delivery Networks |
Résumé:
Recently, the demand for content delivery in wired/wireless heterogeneous networks is increasing at a rapid pace. Content Distribution/Delivery Networks (CDNs) are considered to be one of the best solutions for dealing with this increasing demand. In this paper, we point out that the performance of a CDN typically degrades in such heterogeneous environments due to the changes in not only user demand but also wireless mobility, which triggers unexpected fluctuations in traffic. Wireless users, roaming between different access networks, may contribute to sudden and unexpected demand spikes in certain parts of the content delivery system. To address this issue, we develop a cooperative server selection scheme, which is designed to maximize robustness to such changes with the cooperation between the content delivery system and its users. The performance of our proposal is evaluated by extensive computer simulations. The evaluation results demonstrate that our proposed scheme effectively makes the considered content delivery system resilient against request fluctuations while minimizing system overloading. |
| Auteurs: Nishiyama, Hiroki;Yamada, Hiroshi;Yoshino, Hideaki;Kato, Nei; |
| Apparue dans: IEEE Journal on Selected Areas in Communications |
| Date publication: 02.-2012, volume: 30, issue:2, pages: 476 - 483 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Critique of Geoengineering |
Résumé:
Interest in “geoengineering” technologies has increased significantly over the past few years because of concern about global climate change coupled with a growing recognition of the inadequacies of the Kyoto Protocol and the ongoing climate change negotiating process. |
| Auteurs: Allenby, B.; |
| Apparue dans: IEEE Potentials |
| Date publication: 02.-2012, volume: 31, issue:1, pages: 22 - 26 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Current-Mode DC–DC Buck Converter with Efficiency-Optimized Frequency Control and Reconfigurable Compensation |
Résumé:
Large input voltage range and wide output current range are usually needed for dc-dc converters. For these input and output conditions, the converter's efficiency can be maximized by a proposed method, efficiency-optimized switching-frequency (EOF) control. The optimal switching frequency for maximizing the efficiency is generated by the low-complexity and low-power EOF generator. A reconfigurable compensator is developed for improving the load regulation and the transient response. A piecewise-linear current sensor (PLCS) is employed to reduce controller power loss without sacrificing the sensing accuracy. With the aforementioned three proposed methods, a monolithic current-mode dc-dc buck converter is implemented in a 0.35-μm 3.3-V CMOS process. The measured power-loss reductions and efficiency improvements achieve 16 and 15 mW, and 16% and 1%, both in light and heavy loads, respectively. The load regulation and the transient recovery time are improved by 40 mV and 12 μs, respectively, while the PLCS can reduce 3 mW of power loss. Compared with other published converters in 0.35-μm CMOS process, the implemented converter achieves a higher efficiency of 96.3% and smaller chip area of 0.97 mm. |
| Auteurs: Jia-Ming Liu;Pai-Yi Wang;Tai-Haur Kuo; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 869 - 880 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Differential Digitally Controlled Crystal Oscillator With a 14-Bit Tuning Resolution and Sine Wave Outputs for Cellular Applications |
Résumé:
This paper describes the design topologies and considerations of a differential sinusoidal-output digitally controlled crystal oscillator (DCXO) intended for use in cellular applications. The oscillator has a fine-tuning range of  44 ppm, approximately 14 bits of resolution, and an average step size of 0.005 ppm. All signals connecting externally to I/O pins are sine waves for reducing noise, interference, and spurs couplings. The 26 MHz DCXO fabricated in 65 nm CMOS achieves a phase noise of 149.1 dBc/Hz at 10 kHz offset measured at the sine wave buffer output. The DCXO is capable of meeting the stringent phase noise requirements for IEEE 802.11n 5 GHz WLAN devices. A typical frequency pulling of 0.01 ppm due to turning on/off the sine wave buffer is measured. The DCXO dissipates 1.2 mA of current, whereas each sine wave output buffer draws 1.4 mA. The DXCO occupies a total silicon area of 0.15 mm . |
| Auteurs: Chang, Y.;Leete, J.;Zhou, Z.;Vadipour, M.;Chang, Y.-T.;Darabi, H.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 421 - 434 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Direct AC–AC Converter for Inductive Power-Transfer Systems |
Résumé:
This paper proposes a direct ac-ac converter to generate a high-frequency current for inductive power-transfer (IPT) systems. Unlike traditional dc-ac converters for IPT systems, the proposed converter can achieve a high-frequency current generation directly from an ac power source without a dc link. The power converter can maintain high-frequency resonance by natural circuit oscillation and discrete energy injection control. A variable-frequency control strategy is developed to vary the switching frequency to keep the high-frequency current operating with zero-current switching. Thus, the switching stress, power losses, and electromagnetic interference of the converter are reduced. Theoretical analysis, simulation, and experimental results show that the output track current is fully controllable with good waveforms for contactless power-transfer applications. |
| Auteurs: Hao Leo Li;Hu, A.P.;Covic, G.A.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 661 - 668 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Direct Dynamic Dose-Response Model of Propofol for Individualized Anesthesia Care |
Résumé:
In an effort to open up new opportunities in individualized anesthesia care, this paper presents a dynamic dose-response model of propofol that relates propofol dose (i.e., infusion rate) directly to a clinical effect. The proposed model consists of a first-order equilibration dynamics plus a nonlinear Hill equation model, each representing the transient distribution of propofol dose from the plasma to the effect site and the steady-state dose-effect relationship. Compared to traditional pharmacokinetic-pharmacodynamic (PKPD) models, the proposed model has structural parsimony and comparable predictive capability, making it more attractive than its PKPD counterpart for identifying an individualized dose-response model in real-time. The efficacy of the direct dynamic dose-response model over a traditional PKPD model was assessed using a mixed effects modeling analysis of the electroencephalogram (EEG)-based state entropty (SE) response to intravenous propofol administration in 34 pediatric subjects. An improvement in the mean-squared error and  value of individual prediction, as well as the Akaike’s information criterion (AIC) was seen with the direct dynamic dose-response model. |
| Auteurs: Hahn, J-.O.;Dumont , G. A.;Ansermino, J. M.; |
| Apparue dans: IEEE Transactions on Biomedical Engineering |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 571 - 578 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Distributed Multi-Service Resource Allocation Algorithm in Heterogeneous Wireless Access Medium |
Résumé:
In this paper, radio resource allocation in a heterogeneous wireless access medium is studied. Mobile terminals (MTs) are assumed to have multi-homing capabilities. Both constant bit rate and variable bit rate services are considered. A novel algorithm is developed for the resource allocation. Unlike existing solutions in literature, the proposed algorithm is distributed in nature, such that each network base station / access point can perform its own resource allocation to support the MTs according to their service classes. The coordination among different available wireless access networks' base stations is established via the MT multiple radio interfaces in order to provide the required bandwidth to each MT. A priority mechanism is employed, so that each network gives a higher priority on its resources to its own subscribers as compared to other users. Numerical results demonstrate the validity of the proposed algorithm. |
| Auteurs: Ismail, Muhammad;Zhuang, Weihua; |
| Apparue dans: IEEE Journal on Selected Areas in Communications |
| Date publication: 02.-2012, volume: 30, issue:2, pages: 425 - 432 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Distributed Topology Control Technique for Low Interference and Energy Efficiency in Wireless Sensor Networks |
Résumé:
Topology control plays an important role in the design of wireless ad hoc and sensor networks; it is capable of constructing networks that have desirable characteristics such as sparser connectivity, lower transmission power, and a smaller node degree. In this research, a new distributed topology control technique is presented that enhances energy efficiency and reduces radio interference in wireless sensor networks. Each node in the network makes local decisions about its transmission power and the culmination of these local decisions produces a network topology that preserves global connectivity. Central to this topology control technique is the novel Smart Boundary Yao Gabriel Graph (SBYaoGG) and optimizations to ensure that all links in the network are symmetric and energy efficient. Simulation results are presented demonstrating the effectiveness of this new technique as compared to other approaches to topology control. |
| Auteurs: Chiwewe, T. M.;Hancke, G. P.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 11 - 19 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Fast Majorize–Minimize Algorithm for the Recovery of Sparse and Low-Rank Matrices |
Résumé:
We introduce a novel algorithm to recover sparse and low-rank matrices from noisy and undersampled measurements. We pose the reconstruction as an optimization problem, where we minimize a linear combination of data consistency error, nonconvex spectral penalty, and nonconvex sparsity penalty. We majorize the nondifferentiable spectral and sparsity penalties in the criterion by quadratic expressions to realize an iterative three-step alternating minimization scheme. Since each of these steps can be evaluated either analytically or using fast schemes, we obtain a computationally efficient algorithm. We demonstrate the utility of the algorithm in the context of dynamic magnetic resonance imaging (MRI) reconstruction from sub-Nyquist sampled measurements. The results show a significant improvement in signal-to-noise ratio and image quality compared with classical dynamic imaging algorithms. We expect the proposed scheme to be useful in a range of applications including video restoration and multidimensional MRI. |
| Auteurs: Hu, Y.;Lingala, S. G.;Jacob, M.; |
| Apparue dans: IEEE Transactions on Image Processing |
| Date publication: 02.-2012, volume: 21, issue:2, pages: 742 - 753 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Fast Parts-Based Approach to Speaker Verification Using Boosted Slice Classifiers |
Résumé:
Speaker verification (SV) on portable devices like smartphones is gradually becoming popular. In this context, two issues need to be considered: 1) such devices have relatively limited computation resources, and 2) they are liable to be used everywhere, possibly in very noisy, uncontrolled environments. This work aims to address both these issues by proposing a computationally efficient yet robust SV system. This novel parts-based system draws inspiration from face and object detection systems in the computer vision domain. The system involves boosted ensembles of simple threshold-based classifiers. It uses a novel set of features extracted from speech spectra, called “slice features.” The performance of the proposed system was evaluated through extensive studies involving a wide range of experimental conditions using the TIMIT, HTIMIT, and MOBIO corpus, against standard cepstral features and Gaussian Mixture Model-based SV systems. |
| Auteurs: Roy, A.;Magimai.-Doss, M.;Marcel, S.; |
| Apparue dans: IEEE Transactions on Information Forensics and Security |
| Date publication: 02.-2012, volume: 7, issue:1, pages: 241 - 254 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Fast Robust Optimization Methodology Based on Polynomial Chaos and Evolutionary Algorithm for Inverse Problems |
Résumé:
This paper explores the potential of polynomial chaos in robust designs of inverse problems. A fast numerical methodology based on combinations of polynomial chaos expansion and evolutionary algorithm is reported in this study. With the proposed methodology, polynomial chaos expansion is used as a stochastic response surface model for efficient computations of the expectancy metric of the objective function. Additional enhancements, such as the introduction of a new methodology for expected fitness assignment and probability feasibility model, a novel driving mechanism to bias the next iterations to search for both global and robust optimal solutions, are introduced. Numerical results on two case studies are reported to illustrate the feasibility and merits of the present work. |
| Auteurs: Ho, S. L.;Yang, S.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 259 - 262 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Fault Detection and Protection Scheme for Three-Level DC–DC Converters Based on Monitoring Flying Capacitor Voltage |
Résumé:
Fault detection and protection is an important design aspect for any power converter, especially in high-power high-voltage applications, where cost of failure can be high. The three-level dc-dc converter and its varied derivatives are attractive topologies in high-voltage high-power converter applications. The protection method can not only prevent the system failure against unbalanced voltage stresses on the switches, but also provide a remedy for the system as faults occur and save the remaining components. The three-level converter is subject to voltage unbalance in certain abnormal conditions, which can result in switch overvoltage and system failure. The reasons for the unbalanced voltage stresses are fully investigated and categorized. The solutions to each abnormal condition are introduced. In addition to the voltage unbalance, the three-level converters can be protected against multiple faults by the proposed protection method through monitoring the flying capacitor voltage. Phenomena associated with each fault are thoroughly analyzed and summarized. The protection circuit is simple and can be easily implemented, while it can effectively protect the three-level converters and its derivatives, which has been verified by the experiment with a three-level parallel resonant converter. |
| Auteurs: Honggang Sheng;Fei Wang;Tipton, C.W.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 685 - 697 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Ferroelectric and Charge Hybrid Nonvolatile Memory—Part I: Device Concept and Modeling |
Résumé:
We present a new one-transistor hybrid nonvolatile memory based on the combination of two distinctive mechanisms, namely, remanent polarization in ferroelectrics and charge injection into floating nodes. The gate stack design and the memory operation of the hybrid device are aimed to offer mutually complementing benefits between the two mechanisms, thereby presenting superior performance over conventional ferroelectric (FE) FET and gate injection-based Flash memory. During program operation, a high negative bias at the gate orients the ferroelectric polarization to the applied field. In addition, electrons at the gate electrode also tunnel into the floating nodes located between the ferroelectric thin film and the thin top tunnel dielectric and increase the total memory window. High electric displacement in the ferroelectric enables field enhancement in the tunnel dielectric for faster program and erase operations. During retention, the injected electrons reduce the depolarization field in the ferroelectrics, and the remanent polarization reduces the electric field in the tunnel oxide, which helps in the longer retention of the programmed state by the two additive memory mechanisms. Part I evaluates the benefits of the hybrid gate stack through 1-D simulations incorporating the polarization–field  – $) hysteresis in the ferroelectric layer. The simulations provide a guideline for optimal gate stack design of the proposed hybrid memory. The following Part II then discusses the fabrication and experimental validation. |
| Auteurs: Rajwade, S. R.;Auluck, K.;Phelps, J. B.;Lyon, K. G.;Shaw, J. T.;Kan, E. C.; |
| Apparue dans: IEEE Transactions on Electron Devices |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 441 - 449 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A field study of aging in paper-oil insulation systems |
Résumé:
The paper used to insulate the windings of power transformers is mostly made from wood pulp, a cellulosic material. Over decades the paper is slowly attacked by water, oxygen, oil acids, and high temperatures and eventually degrades to the point where it is no longer an effective insulator. The transformer is then likely to fail. Power utilities need to know when a transformer is nearing the end of its useful life in order to plan its replacement. However, a problem with monitoring the condition of the paper within a transformer is that it may be difficult to obtain a sample to test. Furthermore, a particular sample may not accurately reflect the overall paper condition. A power transformer operating in Australia failed in 2010. Thus we had the opportunity to study the paper condition at various points within the transformer and evaluate the validity of the current understanding of paper aging. In this article we discuss the mechanisms of cellulose degradation, and the associated equations, and apply them to the paper insulation in the failed transformer. |
| Auteurs: Lelekakis, N.;Guo, W.;Martin, D.;Wijaya, J.;Susa, D.; |
| Apparue dans: IEEE Electrical Insulation Magazine |
| Date publication: 02.-2012, volume: 28, issue:1, pages: 12 - 19 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Finite Element Subproblem Method for Position Change Conductor Systems |
Résumé:
Analyses of magnetic systems with position changes of both massive and stranded conductors are performed via a finite element subproblem method. A complete problem is split into subproblems associated with each conductor and the magnetic regions. Each complete solution is then expressed as the sum of subproblem solutions supported by different meshes. The subproblem procedure simplifies both meshing and solving processes, with no need of remeshing, and accurately quantifies the effect of the position changes of conductors on both local fields, e.g., skin and proximity effects, and global quantities, e.g., inductances and forces. Applications covering parameterized analyses on conductor positions to moving conductor systems can benefit from the developed approach. |
| Auteurs: Dular, P.;Krahenbuhl, L.;Sabariego, R. V.;Ferreira da Luz, M. V.;Kuo-Peng, P.;Geuzaine, C.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 403 - 406 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Finite-Element Variable Time-Stepping Algorithm for Solving the Electromagnetic Diffusion Equation |
Résumé:
This paper presents a new methodology for applying the Backward Differentiation Formula (BDF) and the Theta algorithm for the variable time-stepping finite-element discretization. The developed BDF-Theta formulation was implemented for solving the Electromagnetic Diffusion equation. An initial-guess prediction algorithm was adopted for convergence acceleration. An algorithm for the selection of the order and time-step size is also included. A minimum time step criterion is adopted. The proposed methodology was validated against an analytical solution and good results were obtained. The adaptive time-step (BDF) requires less computation time than using the fixed time-step implicit Euler. |
| Auteurs: Ovando-Martinez, R. B. B.;Arjona Lopez, M. A.;Hernandez Flores, C.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 647 - 650 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Four-Shell Diffusion Phantom of the Head for Electrical Impedance Tomography |
Résumé:
A four-shell head phantom has been built and characterized. Its structure is similar to that of nonhomogeneous concentric shell domains used by numerical solvers that better approximate current distribution than phantoms currently used to validate electrical impedance tomography systems. Each shell represents a head tissue, namely, skin, skull, cerebrospinal fluid, and brain. A novel technique, which employs a volume conductive impermeable film, has been implemented to prevent ion diffusion between different agar regions without affecting current distribution inside the phantom. Comparisons between simulations and phantom measurements performed over four days are given to prove both the adherence to the model in the frequency range between 10 kHz and 1 MHz and its long-term stability. |
| Auteurs: Sperandio, M.;Guermandi, M.;Guerrieri, R.; |
| Apparue dans: IEEE Transactions on Biomedical Engineering |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 383 - 389 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Free-Space Interferometric Refractometer Structure With Simple Microfluidic Chips |
Résumé:
We introduce and experimentally demonstrate an optofluidics-based refractometer structure arranged in a simple free-space Young interferometer design. Our key idea is based on the use of a very simple microfluidic chip structure that consists of one or two flow channels arranged in parallel. We then pass the optical beam through the flow channels of the microfluidic chip. Behind the flow channels, there are two small apertures where the incident optical beam is automatically divided into two optical beams. These two optical beams are propagating in free space for a desired distance before they interfere with each other at the observation plane. Key features include simplicity in design, ease of implementation, and robustness. In the experimental demonstration, we use a 655-nm wavelength laser diode; the free-space propagation distance is 57.5 cm. The two-channel microfluidic chip has a 900-μm channel spacing, a 100-μm channel width, and a 100-μm channel depth (i.e., d/L = 9). Results indicate a sensitivity of 1.34 × 10-4 RIU in measuring the refractive index of the sucrose solution which clearly agrees with the theoretical analysis. A higher sensitivity of 6.19 × 10-6 RIU is also accomplished when the single-channel microfluidic chip with a measured d/L ratio of 0.52 is combined with an optical mask having a 600- μm channel spacing. |
| Auteurs: Sumriddetchkajorn, S.;Chaitavon, K.;Nukeaw, J.; |
| Apparue dans: IEEE Sensors Journal |
| Date publication: 02.-2012, volume: 12, issue:2, pages: 404 - 409 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Fusion Approach for Efficient Human Skin Detection |
Résumé:
A reliable human skin detection method that is adaptable to different human skin colors and illumination conditions is essential for better human skin segmentation. Even though different human skin-color detection solutions have been successfully applied, they are prone to false skin detection and are not able to cope with the variety of human skin colors across different ethnic. Moreover, existing methods require high computational cost. In this paper, we propose a novel human skin detection approach that combines a smoothed 2-D histogram and Gaussian model, for automatic human skin detection in color image(s). In our approach, an eye detector is used to refine the skin model for a specific person. The proposed approach reduces computational costs as no training is required, and it improves the accuracy of skin detection despite wide variation in ethnicity and illumination. To the best of our knowledge, this is the first method to employ fusion strategy for this purpose. Qualitative and quantitative results on three standard public datasets and a comparison with state-of-the-art methods have shown the effectiveness and robustness of the proposed approach. |
| Auteurs: Tan, W. R.;Chan, C. S.;Yogarajah, P.;Condell, J.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 138 - 147 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A GA-API Solution for the Economic Dispatch of Generation in Power System Operation |
Résumé:
This work proposes a novel heuristic-hybrid optimization method designed to solve the nonconvex economic dispatch problem in power systems. Due to the fast computational capabilities of the proposed algorithm, it is envisioned that it becomes an operations tool for both the generation companies and the TSO/ISO. The methodology proposed improves the overall search capability of two powerful heuristic optimization algorithms: a special class of ant colony optimization called API and a real coded genetic algorithm (RCGA). The proposed algorithm, entitled GAAPI, is a relatively simple but robust algorithm, which combines the downhill behavior of API (a key characteristic of optimization algorithms) and a good spreading in the solution space of the GA search strategy (a guarantee to avoid being trapped in local optima). The feasibility of the proposed method is first tested on a number of well-known complex test functions, as well as on four different power test systems having different sizes and complexities. The results are analyzed in terms of both quality of the solution and the computational efficiency; it is shown that the proposed GAAPI algorithm is capable of obtaining highly robust, quality solutions in a reasonable computational time, compared to a number of similar algorithms proposed in the literature. |
| Auteurs: Ciornei, I.;Kyriakides, E.; |
| Apparue dans: IEEE Transactions on Power Systems |
| Date publication: 02.-2012, volume: 27, issue:1, pages: 233 - 242 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Graphic Representation of the Necessary Condition for the MAFA Method |
Résumé:
The modified ambiguity function approach (MAFA) is one of the integer least square estimation methods. Although it is a simple and efficient method, it has a significant limitation. This limitation is formulated and analyzed in this paper. A graphical representation of the necessary condition for the MAFA method is presented by plots of Voronoi cells and error ellipsoids, along with a detailed procedure for constructing these plots. It is shown that the necessary condition for the MAFA method is not satisfied in some cases. To overcome this problem, a solution is presented in the final section of this paper. |
| Auteurs: Cellmer, S.; |
| Apparue dans: IEEE Transactions on Geoscience and Remote Sensing |
| Date publication: 02.-2012, volume: 50, issue:2, pages: 482 - 488 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Hierarchical Model Incorporating Segmented Regions and Pixel Descriptors for Video Background Subtraction |
Résumé:
Background subtraction is important for detecting moving objects in videos. Currently, there are many approaches to performing background subtraction. However, they usually neglect the fact that the background images consist of different objects whose conditions may change frequently. In this paper, a novel hierarchical background model is proposed based on segmented background images. It first segments the background images into several regions by the mean-shift algorithm. Then, a hierarchical model, which consists of the region models and pixel models, is created. The region model is a kind of approximate Gaussian mixture model extracted from the histogram of a specific region. The pixel model is based on the cooccurrence of image variations described by histograms of oriented gradients of pixels in each region. Benefiting from the background segmentation, the region models and pixel models corresponding to different regions can be set to different parameters. The pixel descriptors are calculated only from neighboring pixels belonging to the same object. The experimental results are carried out with a video database to demonstrate the effectiveness, which is applied to both static and dynamic scenes by comparing it with some well-known background subtraction methods. |
| Auteurs: Chen, S.;Zhang, J.;Li, Y.;Zhang, J.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 118 - 127 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A High-Performance Three-Dimensional Microheater-Based Catalytic Gas Sensor |
Résumé:
We report a high-performance catalytic gas sensor based on a 3-D microheater. Two catalytic gas sensors were fabricated by sol-gel process, respectively based on a 3-D microheater with a concave active membrane and a comparative 2-D microheater with a rectangular active membrane, introducing Pd–Pt as catalytic material. Test results of the sensor response to methane indicate that the output signal $) , sensitivity, and signal-to-noise ratio of the 3-D microheater-based gas sensor were more than twice of those of the 2-D microheater-based gas sensor. Moreover, it had a higher output signal-to-power ratio $) . |
| Auteurs: Xu, L.;Li, T.;Gao, X.;Wang, Y.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 284 - 286 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Highly Scalable Interface Fuse for Advanced CMOS Logic Technologies |
Résumé:
In this letter, we propose a novel interface fuse (iFuse) for low-power electrically programmable fuses in advanced CMOS applications. With an offset-landed metal-to-contact or contact-to-polysilicon structure, the iFuse can be programmed by substantially reduced current as compared to conventional fuses. A diagonal contact layout and the optical pattern correction scheme can further improve the cell stability as well as its programming characteristics. |
| Auteurs: Yang, L.-Y.;Hsieh, M.-C.;Liu, J.-S.;Chin, Y.-W.;Lin, C. J.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 245 - 247 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Kalman-Filtering Approach to High Dynamic Range Imaging for Measurement Applications |
Résumé:
High dynamic range imaging (HDRI) methods in computational photography address situations where the dynamic range of a scene exceeds what can be captured by an image sensor in a single exposure. HDRI techniques have also been used to construct radiance maps in measurement applications; unfortunately, the design and evaluation of HDRI algorithms for use in these applications have received little attention. In this paper, we develop a novel HDRI technique based on pixel-by-pixel Kalman filtering and evaluate its performance using objective metrics that this paper also introduces. In the presented experiments, this new technique achieves as much as 9.4-dB improvement in signal-to-noise ratio and can achieve as much as a 29% improvement in radiometric accuracy over a classic method. |
| Auteurs: Dedrick, E.;Lau, D.; |
| Apparue dans: IEEE Transactions on Image Processing |
| Date publication: 02.-2012, volume: 21, issue:2, pages: 527 - 536 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Lifting Based Approach to Observer Based Fault Detection of Linear Periodic Systems |
Résumé:
In this note, an approach based on lifting is introduced for the observer based fault detection (FD) of linear discrete-time periodic systems. The main contribution of this note is to give an analytic expression to transform the linear time-invariant (LTI) observer based residual generator designed based on the lifted LTI reformulation of the periodic system into a periodic observer based residual generator to reduce detection delay. The result enables a systematic transfer of the existing observer based FD methods for discrete LTI systems to discrete-time periodic systems. |
| Auteurs: Zhang, P.;Ding, S. X.;Liu, P.; |
| Apparue dans: IEEE Transactions on Automatic Control |
| Date publication: 02.-2012, volume: 57, issue:2, pages: 457 - 462 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Local Discontinuous Galerkin Method for Eddy Current Field Analysis in High-Speed Moving Conductors |
Résumé:
A numerical method for analyzing eddy current magnetic field in high-speed moving conductors using local discontinuous Galerkin (LDG) method is presented. A typical numerical example is chosen to illustrate the accuracy and nonoscillatory nature of the method for a convection dominated case. The simulation results using the proposed algorithm are validated using standard finite element method (FEM). As an application of LDG method in engineering problems, the TEAM workshop problem 9 is studied and solved by the proposed method with second order rectangular discontinuous elements. Numerical results show that the method can solve eddy current problems with high speed moving conductors accurately. |
| Auteurs: Zhao, Y.;Zhang, X.;Ho, S. L.;Fu, W. N.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 251 - 254 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Local Discontinuous Galerkin Method for Numerical Computation of Waveguide Eigenvalue Problems in Polar Coordinates |
Résumé:
A numerical method for symmetric cylindrical and spherical waveguide eigenvalue problems is presented using local discontinuous Galerkin (LDG) method based on polar coordinates. The method has the merit of having high accuracy without geometrical triangulation errors on the curved boundaries of the solution domain. As an illustration, the formulation of the LDG schemes in both cylindrical polar coordinates and spherical polar coordinates are derived and several numerical examples are presented. Numerical results reported demonstrate that the proposed LDG method can be used readily to solve waveguide eigenvalue problems accurately. |
| Auteurs: Ho, S. L.;Zhao, Y.;Fu, W. N.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 255 - 258 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Low-Frequency Approximation to the Maxwell Equations Simultaneously Considering Inductive and Capacitive Phenomena |
Résumé:
For many technical examples, low-frequency approximations to the full set of the Maxwell equations are applicable. Commonly, either the displacement current density or the induced current density are neglected depending on a priori knowledge about the dominating effects for a specific problem setup. This leads to different subsets of the Maxwell equations describing inductive-resistive or capacitive-resistive systems, respectively. In this paper, a formulation combining both scenarios while maintaining the quasistationary assumption, i.e., without modeling wave propagation and radiation, is presented. The formulation is applied to a simple test model consisting of a bounded massive conductor embedded in a dielectric insulation. |
| Auteurs: Koch, S.;Schneider, H.;Weiland, T.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 511 - 514 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Low-Power BiCMOS 4-Element Phased Array Receiver for 76–84 GHz Radars and Communication Systems |
Résumé:
This paper presents a 76–84 GHz low-power 4- element phased array receiver built using a 0.13 m BiCMOS process. The power consumption is reduced by using a single-ended design and alternating the amplifiers and phase shifter cells to result in a low noise figure at a low power consumption. A variable gain amplifier and an 11 trim bit are used to correct for the rms gain and phase errors at different operating frequencies. The phased array consumes 32 mW per channel and results in a gain of 10–19 dB at 76–84 GHz, a noise figure of 10.5 0.5 dB at 80 GHz and an rms gain and phase error  0.8 dB and  7.2 , respectively, up to 81 GHz, and 1.1 dB and 10.4 up to 84 GHz. The phased array also shows a channel to channel coupling of  30 dB up to 84 GHz. To our knowledge, this work presents state-of-the-art on-chip performance at W-band frequencies. |
| Auteurs: Kim, S. Y.;Rebeiz, G. M.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 359 - 367 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Low-Power Single-Phase Clock Multiband Flexible Divider |
Résumé:
In this paper, a low-power single-phase clock multiband flexible divider for Bluetooth, Zigbee, and IEEE 802.15.4 and 802.11 a/b/g WLAN frequency synthesizers is proposed based on pulse-swallow topology and is implemented using a 0.18-  CMOS technology. The multiband divider consists of a proposed wideband multimodulus 32/33/47/48 prescaler and an improved bit-cell for swallow (S) counter and can divide the frequencies in the three bands of 2.4–2.484 GHz, 5.15–5.35 GHz, and 5.725–5.825 GHz with a resolution selectable from 1 to 25 MHz. The proposed multiband flexible divider is silicon verified and consumes power of 0.96 and 2.2 mW in 2.4- and 5-GHz bands, respectively, when operated at 1.8-V power supply. |
| Auteurs: Manthena, V. K.;Do, M. A.;Boon, C. C.;Yeo, K. S.; |
| Apparue dans: IEEE Transactions on Very Large Scale Integration Systems |
| Date publication: 02.-2012, volume: 20, issue:2, pages: 376 - 380 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Lyapunov Function-Based Robust Direct Torque Controller for a Switched Reluctance Motor Drive System |
Résumé:
A novel Lyapunov function-based direct torque controller for minimization of torque ripples in a switched reluctance motor (SRM) drive system is reported in this paper. SRM magnetization characteristics are highly nonlinear, where torque is a complex and coupled function of the phase currents and rotor position. The direct torque control (DTC) scheme avoids the complex process of torque-to-current conversion as required in indirect torque control scheme. The traditional DTC scheme uses a hysteresis-type torque controller and it leads to large amount of torque ripples when implemented digitally. The proposed controller is intended to take care of the nonlinear system dynamics of magnetic characteristics associated with accurate torque control using DTC scheme for the SRM drive system. In the Lyapunov function-based controller, the feedback gain is varied using a heuristic technique. The stability of the proposed controller is ensured by the direct method of Lyapunov. Experimental results for a 1-hp, 4-phase SRM are provided to demonstrate the efficacy of the proposed torque control scheme. |
| Auteurs: Sahoo, S.K.;Dasgupta, S.;Panda, S.K.;Jian-Xin Xu; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 555 - 564 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Matrix-Based Approach to Unsupervised Human Action Categorization |
Résumé:
Human action, as the basic unit of most human-relevant video content, bridges the gap between low-level visual features and high-level semantics. Human action recognition is of great significance in the applications of human-computer interaction, intelligent video surveillance, video retrieval and search. In this paper, we propose a novel unsupervised approach to mining categories from action video sequences, which consists of two modules: action representation for video data structurization and learning model for unsupervised categorization. In action representation, a novel view of video decomposition is presented. Videos are regarded as spatially distributed dynamic pixel time series, and these dynamic pixels are first quantized into pixel prototypes. After replacing the pixel time series with their corresponding prototype labels, the video sequences are compressed into two-dimensional action matrices. In the learning model, we put these matrices together to form an multi-action tensor, and propose the joint matrix factorization method to simultaneously cluster the pixel prototypes into pixel signatures, and matrices into action classes with the consideration of the duality between pixel clustering and action clustering. The approach is tested on public and popular Weizmann, and KTH datasets, and promising results are achieved. |
| Auteurs: Cui, P.;Wang, F.;Sun, L.-F.;Zhang, J.-W.;Yang, S.-Q.; |
| Apparue dans: IEEE Transactions on Multimedia |
| Date publication: 02.-2012, volume: 14, issue:1, pages: 102 - 110 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Maximum Entropy Enhancement for a Family of High-Resolution Spectral Estimators |
Résumé:
Structured covariances occurring in spectral analysis, filtering and identification need to be estimated from a finite observation record. The corresponding sample covariance usually fails to possess the required structure. This is the case, for instance, in the Byrnes–Georgiou–Lindquist THREE-like tunable, high-resolution spectral estimators. There, the output covariance  of a linear filter is needed to initialize the spectral estimation technique. The sample covariance estimate  , however, is usually not compatible with the filter. In this paper, we present a new, systematic way to overcome this difficulty. The new estimate  is obtained by solving an ancillary problem with an entropic-type criterion. Extensive scalar and multivariate simulation shows that this new approach consistently leads to a significant improvement of the spectral estimators performances. |
| Auteurs: Ferrante, A.;Pavon, M.;Zorzi, M.; |
| Apparue dans: IEEE Transactions on Automatic Control |
| Date publication: 02.-2012, volume: 57, issue:2, pages: 318 - 329 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Maximum Likelihood Approach to Estimation of Vector Velocity in Doppler Radar Networks |
Résumé:
In this paper, a vector velocity estimation approach based on the maximum likelihood technique operating on moment data within the overlapping area of a network of Doppler radars is presented. The relationships between the estimated vector velocity, the statistics of the measured signal, the characteristics of the observing geometry and volume, and the hardware and signal processing parameters are all derived. The most relevant error sources to the network measurements are derived and incorporated into the overall estimation process. The relationship between the measurement and estimation errors is identified, and exploited, so that estimation performance can be measured and, if necessary, improved through the means of error norm minimization. Techniques for mitigating errors in the synthesized reflectivity and velocity folding are presented as well. Results with error metrics are shown for several typical weather observation scenarios that include error sources and simulated data. Finally, it is shown how the technique may be used to provide useful information for the design and intercomparison of various Doppler radar network geometries. |
| Auteurs: Insanic, E.;Siqueira, P. R.; |
| Apparue dans: IEEE Transactions on Geoscience and Remote Sensing |
| Date publication: 02.-2012, volume: 50, issue:2, pages: 553 - 567 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Mesh-Insensitive Methodology for Magnetic Force Computation in Finite-Element Analysis |
Résumé:
A novel mesh-insensitive methodology for magnetic force computation is presented. The force value is obtained by integration on several layers of mesh elements around the objects on which the force needs to be computed. The number of layers can be automatically determined during computation and the force computation on objects touching each other can also be evaluated accurately. The computation results are compared with those obtained using traditional Maxwell stress tensor method and normal virtual work method. The results confirm that the sensitivity of the computed force to the mesh quality is greatly reduced and the accuracy of the force computation is increased. |
| Auteurs: Ho, S. L.;Niu, S.;Fu, W. N.;Zhu, J.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 287 - 290 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Miniature Vibrotactile Sensory Substitution Device for Multifingered Hand Prosthetics |
Résumé:
A multisite, vibrotactile sensory substitution system, that could be used in conjunction with artificial touch sensors in multifingered prostheses, to deliver sensory feedback to upper limb amputees is presented. The system is based on a low cost/power/size smart architecture of off-the-shelf miniaturized vibration motors; the main novelty is that it is able to generate stimuli where both vibration amplitude and frequency as well as beat interference can be modulated. This paper is aimed at evaluating this system by investigating the capability of healthy volunteers to perceive—on their forearms—vibrations with different amplitudes and/or frequencies. In addition, the ability of subjects in spatially discriminating stimulations on three forearm sites and recognizing six different combinations of stimulations was also addressed. Results demonstrate that subjects were able to discriminate different force amplitudes exerted by the device (accuracies greater than 75%); when both amplitude and frequency were simultaneously varied, the pure discrimination of amplitude/frequency variation was affected by the variation of the other. Subjects were also able to discriminate with an accuracy of 93% three different sites and with an accuracy of 78% six different stimulation patterns. |
| Auteurs: Cipriani, C.;D’Alonzo, M.;Carrozza, M. C.; |
| Apparue dans: IEEE Transactions on Biomedical Engineering |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 400 - 408 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Model-Based Shot Boundary Detection Technique Using Frame Transition Parameters |
Résumé:
We have presented a unified model for detecting different types of video shot transitions. Based on the proposed model, we formulate frame estimation scheme using the previous and the next frames. Unlike other shot boundary detection algorithms, instead of properties of frames, frame transition parameters and frame estimation errors based on global and local features are used for boundary detection and classification. Local features include scatter matrix of edge strength and motion matrix. Finally, the frames are classified as no change (within shot frame), abrupt change, or gradual change frames using a multilayer perceptron network. The proposed method is relatively less dependent on user defined thresholds and is free from sliding window size as widely used by various schemes found in the literature. Moreover, handling both abrupt and gradual transitions along with non-transition frames under a single framework using model guided visual feature is another unique aspect of the work. |
| Auteurs: Mohanta, P. P.;Saha, S. K.;Chanda, B.; |
| Apparue dans: IEEE Transactions on Multimedia |
| Date publication: 02.-2012, volume: 14, issue:1, pages: 223 - 233 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Modified Imperialist Competitive Algorithm for Optimization in Electromagnetics |
Résumé:
Recently, a new kind of socio-politically motivated global search metaheuristic called imperialist competitive algorithm (ICA) was proposed. ICA is based on a form of imperialistic competition in which the populations are represented by countries divided among imperialists and colonies. In this paper, a modified ICA (MICA) approach based on concepts of attraction and repulsion between the colony and its imperialist is introduced during the search for better solutions. A brushless direct current wheel motor benchmark problem is used to investigate the performance of the classical ICA and the proposed MICA and results are shown to be competitive with those of other well-established optimization methods. |
| Auteurs: Coelho, L. D. S.;Afonso, L. D.;Alotto, P.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 579 - 582 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Multi-Objective Evolutionary Algorithm Based on Decomposition for Optimal Design of Yagi-Uda Antennas |
Résumé:
This paper presents a multi-objective evolutionary algorithm based on decomposition (MOEA/D) to design broadband optimal Yagi-Uda antennas. A multi-objective problem is formulated to achieve maximum directivity, minimum voltage standing wave ratio and maximum front-to-back ratio. The algorithm was applied to the design of optimal 3 to 10 elements Yagi-Uda antennas, whose optimal Pareto fronts are provided in a single picture. The multi-objective problem is decomposed by Chebyshev decomposition, and it is solved by differential evolution (DE) and Gaussian mutation operators in order to provide a better approximation of the Pareto front. The results show that the implemented MOEA/D is efficient for designing Yagi-Uda antennas. |
| Auteurs: Carvalho, R.;Saldanha, R. R.;Gomes, B. N.;Lisboa, A. C.;Martins, A. X.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 803 - 806 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Multiaperture Bioinspired Sensor With Hyperacuity |
Résumé:
We have developed a multiaperture sensor based on the visual system of the common housefly (Musca domestica). The Musca domestica insect has compound eyes, which have been shown to exhibit the ability to detect object motion much finer than their photoreceptor spacing suggests, a phenomenon often called motion hyperacuity. We describe how such motion hyperacuity can be achieved through a controlled preblurring of an optical imaging system. We used this method to develop a software model of a new fly eye sensor and to optimize its motion hyperacuity. Finally, we compare the completed sensor to previously developed fly eye sensors. The new design shows a threefold improvement in signal-to-noise ratio and motion acuity. |
| Auteurs: Luke, G.P.;Wright, C.H.G.;Barrett, S.F.; |
| Apparue dans: IEEE Sensors Journal |
| Date publication: 02.-2012, volume: 12, issue:2, pages: 308 - 314 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Negative Sequence Compensation Method Based on a Two-Phase Three-Wire Converter for a High-Speed Railway Traction Power Supply System |
Résumé:
This paper presents a negative sequence compensation system based on a novel two-phase three-wire converter to eliminate a negative sequence current for the high-speed railway traction power system with a three-phase V/V traction transformer. In this compensation system, the proposed two-phase three-wire converter is fed by two single-phase power sources formed with two step-down transformers connecting to the two feeder sections. The proposed converter contains three switch legs, one of which is connected to the common ground wire of two single-phase voltages. Hence, a switch leg is saved compared with two conventional single-phase converters, and the ratings of the power switches are not increased. In order to enhance the dynamic and steady-state performances of the compensation system, a compound control method composed of hysteresis control and dividing frequency control is presented. Simulation and experimental results are presented to demonstrate that the proposed compensator and its control strategy are very effective. |
| Auteurs: Chuanping Wu;An Luo;Shen, J.;Fu Jun Ma;Shuangjian Peng; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 706 - 717 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Acceleration Factor Decision Method for ICCG Method Based on Condition Number |
Résumé:
The ICCG method is widely used to solve a sparse symmetric linear system which results from the finite element method. In order to improve the convergence property of the ICCG method, the introduction of the acceleration factor was proposed. The automatic acceleration factor decision method, using the incomplete Cholesky decomposition of a coefficient matrix, has been previously proposed. However, when employing the previously proposed automatic decision method, much more iterations of ICCG method are sometimes necessary, compared with using the optimum acceleration factor, which minimizes the number of ICCG iterations. In this paper, we propose a new acceleration factor decision method. The proposed method takes into account the condition number of the coefficient matrix. It is well known that the condition number represents the quality of the matrix, so the optimum acceleration factor should be decided to minimize the condition number of the coefficient matrix. However, the condition number of the coefficient matrix is not almost available due to requiring a large memory in computing. Therefore, we develop a new method using submatrix, that does not need a large memory. The procedure and demonstration of the proposed method are described in this paper. |
| Auteurs: Takada, A.;Noguchi, S.;Igarashi, H.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 519 - 522 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Adaptive Line Enhancer Based on Singular Spectrum Analysis |
Résumé:
Original adaptive line enhancer (ALE) is used for denoising periodic signals from white noise. ALE, however, relies mainly on second order similarity between the signal and its delayed version and is more effective when the signal is narrowband. A new ALE based on singular spectrum analysis (SSA) is proposed here. In this approach in the reconstruction stage of SSA, the eigentriples are adaptively selected (filtered) using the delayed version of the data. Unlike the conventional ALE where (second) order statistics are taken into account, here the full eigen-spectrum of the embedding matrix is exploited. Consequently, the system works for non-Gaussian noise and wideband periodic signals. By performing some experiments on synthetic signals it is demonstrated that the proposed system is very effective for separation of biomedical data, which often have some periodic or quasi-periodic components, such as EMG affected by ECG artefacts. This data are examined here. |
| Auteurs: Sanei, S.;Lee, T. K. M.;Abolghasemi, V.; |
| Apparue dans: IEEE Transactions on Biomedical Engineering |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 428 - 434 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Approach to Implementing High-Frequency Correlated Noise for Bipolar Transistor Compact Modeling |
Résumé:
A new approach to implementing correlated high-frequency noise in bipolar junction transistor (BJT) large-signal compact models is developed by placing an  -delayed noise current between the base and collector nodes. The approach reproduces the two stages of noise transport in a BJT, i.e., noise generation in the base and emitter and transportation through the collector–base junction space-charge region (CB SCR). The frequency dependence of the intrinsic noise sources due to the CB SCR is fully described with an accuracy value up to the second order of  . As an example, the negative frequency dependence of  is correctly described for the first time. The approach is applicable to any large-signal compact model, and it is demonstrated using measurement data in both InGaP/GaAs heterojunction bipolar transistors (HBTs) and SiGe HBTs. |
| Auteurs: Xia, K.;Niu, G.;Xu, Z.; |
| Apparue dans: IEEE Transactions on Electron Devices |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 302 - 308 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Dual Current-Mode Controller Improves Power Regulation in Electrosurgical Generators |
Résumé:
A new dual current-mode controller produces a fast, accurate constant-power high-frequency ac output, with maximum current and voltage limits for an electrosurgical generator. The regulation of ac output power is achieved with near-deadbeat control, without measurement or feedback of the output voltage or current. Compared to existing technology, the prototype generator reduces unintended tissue damage by significantly improving regulation of output power, while reducing complexity and parts count. |
| Auteurs: Friedrichs, D. A.;Erickson, R. W.;Gilbert, J.; |
| Apparue dans: IEEE Transactions on Biomedical Circuits and Systems |
| Date publication: 02.-2012, volume: 6, issue:1, pages: 39 - 44 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New High Efficiency Current Source Driver With Bipolar Gate Voltage |
Résumé:
A novel bipolar current source driver (CSD) for power MOSFETs is proposed in this paper. The proposed bipolar CSD alleviates the gate current diversion problem of the existing CSDs by clamping the gate voltage to a flexible negative value (such as -3.5 V) during turn-off transition. Therefore, the proposed driver is able to turn off the MOSFET much faster with a higher effective gate current. The idea presented in this paper can also be extended to other CSDs to further improve the efficiency with high output currents. The experimental results verify the benefits of the proposed CSD. For buck converters with 12 V input at 1 MHz switching frequency, the proposed driver improves the efficiency from 80.5% using the existing CSD to 82.5% (an improvement of 2%) at 1.2 V/30 A, and at 1.3 V/30 A output, from 82.5% using the existing CSD to 83.9% (an improvement of 1.4%). |
| Auteurs: Jizhen Fu;Zhiliang Zhang;Yan-Fei Liu;Sen, P.C.;Lusheng Ge; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 985 - 997 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Index and Classification Approach for Load Pattern Analysis of Large Electricity Customers |
Résumé:
Conducting load pattern analysis is an important task in obtaining typical load profiles (TLPs) of customers and grouping them into classes according to their load characteristics. When using clustering techniques to obtain the load patterns of electricity customers, choosing a suitable clustering algorithm and determining an appropriate cluster number are always important and difficult issues. Therefore, this paper proposes a stability index for choosing the most suitable clustering algorithm and a priority index (based on the stability index) for determining the priority rank of clusters. Based on three known clustering algorithms, an analysis approach is presented to demonstrate the use of these indices. In the approach, all load curves of customers are first clustered with the clustering algorithms under a serial given number of clusters. The two above-mentioned indices are then calculated. Following this, the most suitable clustering algorithm is chosen and the optimal number of clusters can be determined from the rank list for special application purposes. A case study with large electricity customers connected to a distribution network in Northern China illustrates the approach. The results prove the efficiency of the approach using the proposed indices in the classification and generation of the TLPs of large electricity customers. |
| Auteurs: Zhang, T.;Zhang, G.;Lu, J.;Feng, X.;Yang, W.; |
| Apparue dans: IEEE Transactions on Power Systems |
| Date publication: 02.-2012, volume: 27, issue:1, pages: 153 - 160 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Integral Formulation for Eddy Current Computation in Thin Conductive Shells |
Résumé:
In order to compute eddy current distributions in thin conductive nonmagnetic shells, a new integral formulation is proposed. The method is based on a surface impedance condition which takes into account the field variation through depth due to skin effect. It is general and enables the modeling of various problems whatever their skin-depth and avoiding the meshing of the air region. |
| Auteurs: Le-Duc, T.;Meunier, G.;Chadebec, O.;Guichon, J.-M.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 427 - 430 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Method for Spatial Power Network Planning in Complicated Environments |
Résumé:
This paper presents a novel methodology for the spatial power network planning problem based on the raster map in geographic information systems (GIS). Considering candidate lines and cell linkages, the proposed spatial power network planning model integrates the optimal electric line routing and the power network evaluation, with the objective of the minimum line investment cost. The network connectivity with candidate line routes and the hourly network evaluation for peak power loads are considered to ensure the feasibility of the line path and the security of power systems. The derived mixed-integer nonlinear programming (MINLP) formulation is transformed into a mixed-integer linear programming (MILP) problem by integer algebra techniques. Furthermore, in order to improve the computational efficiency, a tighter MILP formulation with the proposed enhanced line routing constraints is proposed. Numerical case studies illustrate the effectiveness of the proposed approach for the spatial power network planning problem. |
| Auteurs: Shu, J.;Wu, L.;Li, Z.;Shahidehpour, M.;Zhang, L.;Han, B.; |
| Apparue dans: IEEE Transactions on Power Systems |
| Date publication: 02.-2012, volume: 27, issue:1, pages: 381 - 389 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Methodology for Early Stage Magnetic Modeling and Simulation of Complex Electronic Systems |
Résumé:
This paper presents a new methodology called Flex-CM for Flexible Compact Modeling to generate and reuse compact models, in order to build a full model of a complex electronic system at an early stage of the design flow. The system is split into independent parts. Each part is numerically modeled using a discrete approach then reduced to save memory and time at the simulation stage. The resulting pluggable and reduced model is called a micro-model. Then, a fast-to-simulate macro-model of a full system can be obtained by assembling the micro-models. The Flex-CM model is presented as a trade-off between reluctance networks and numerical models to perform a magnetic analysis at an early stage of the system design. The Flex-CM models are found to have number of advantages over both methods, resulting however on larger models than reluctance networks. |
| Auteurs: Martins, O.;Guedon, S.;Marechal, Y.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 319 - 322 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Optimal Design Method of Rotor Slot of Three-Phase Squirrel Cage Induction Motor for NEMA Class D Speed-Torque Characteristic Using Multi-Objective Optimization Algorithm |
Résumé:
This paper presents a systematic optimal design algorithm to design the shape of rotor slot to get a specific speed-torque characteristic in three-phase squirrel cage induction motor for the application to motor operated valve (MOV) actuator. The developed method consists of three steps: design based on equivalent circuit method (ECM) utilizing multi-objective formulation, selection of the strongly influential geometric parameters of rotor slot, and precise design based on finite element method (FEM). The validity of the suggested design method is demonstrated through applications to rotor slot design of three-phase induction motor to achieve a NEMA class D speed-torque characteristic. |
| Auteurs: Zhang, D.;Park, C. S.;Koh, C. S.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 879 - 882 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A New Year |
Résumé:
Editor in Chief Gabriel Taubin discusses the Meet the Editors panel discussion he participated in at VisWeek and IEEE Computer Graphics and Applications' new best article award. He encourages people to submit full-length articles for peer review as well as shorter articles for CG&A's departments. |
| Auteurs: Taubin, Gabriel; |
| Apparue dans: IEEE Computer Graphics and Applications |
| Date publication: 02.-2012, volume: 32, issue:1, pages: 6 - 6 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Nonintrusive Winding Heating Method for Induction Motor Using Soft Starter for Preventing Moisture Condensation |
Résumé:
Moisture condensation may cause degradation of key motor components when a motor is de-energized. To prevent moisture condensation, a motor's temperature must be maintained higher than the ambient temperature when de-energized. This paper proposes a nonintrusive motor heating technique using soft starters. By controlling the operation of the solid-state switches in soft starters, adjustable ac current can be injected into the three phases of the stator windings without inducing any output torque. The motor temperature can therefore be maintained at a desired temperature due to the heat dissipation during current injection. In addition, two motor temperature control approaches are proposed in this paper to minimize the required energy consumption for preventing moisture condensation. The proposed technique is experimentally validated on a 7.5-hp ODP (open drip proof) induction motor. The experimental results show that the average stator winding temperature can reach 9 above the ambient temperature with acceptable current magnitudes. In addition, it is shown that the motor temperature rise can be controlled by adjusting the operation of the solid-state switches in soft starters. The importance of the proposed technique lies in its noninvasive nature: the technique only uses the existing hardware of soft starters; the motor's condition is not interrupted since no output torque is induced during the current injection. The proposed winding heating technique can be easily extended to other types of ac machines or inverter-fed applications. |
| Auteurs: Zhang, P.;Du, Y.;Habetler, T. G.;Lu, B.; |
| Apparue dans: IEEE Transactions on Industry Applications |
| Date publication: 02.-2012, volume: 48, issue:1, pages: 117 - 123 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Nonlocal SAR Image Denoising Algorithm Based on LLMMSE Wavelet Shrinkage |
Résumé:
We propose a novel despeckling algorithm for synthetic aperture radar (SAR) images based on the concepts of nonlocal filtering and wavelet-domain shrinkage. It follows the structure of the block-matching 3-D algorithm, recently proposed for additive white Gaussian noise denoising, but modifies its major processing steps in order to take into account the peculiarities of SAR images. A probabilistic similarity measure is used for the block-matching step, while the wavelet shrinkage is developed using an additive signal-dependent noise model and looking for the optimum local linear minimum-mean-square-error estimator in the wavelet domain. The proposed technique compares favorably w.r.t. several state-of-the-art reference techniques, with better results both in terms of signal-to-noise ratio (on simulated speckled images) and of perceived image quality. |
| Auteurs: Parrilli, S.;Poderico, M.;Angelino, C. V.;Verdoliva, L.; |
| Apparue dans: IEEE Transactions on Geoscience and Remote Sensing |
| Date publication: 02.-2012, volume: 50, issue:2, pages: 606 - 616 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Nonpiecewise Model for Long-Channel Junctionless Cylindrical Nanowire FETs |
Résumé:
A nonpiecewise drain current model is formulated for long-channel junctionless (JL) cylindrical nanowire (CN) FETs. It is obtained by using the Pao–Sah integral and a continuous charge model, which is derived by extending the parabolic potential approximation in all regions of the device operation. The proposed nonpiecewise model analytically describes the bulk and surface current mechanisms in JL CN FETs from the subthreshold region through the linear region to the saturation region without any fitting parameters. In addition, for each of these operation regions, the model reduces to simple expressions that explain the working principle of JL CN FETs. The model is compared with numerical simulations and shows good agreement. |
| Auteurs: Duarte, J. P.;Choi, S.-J.;Moon, D.-I.;Choi, Y.-K.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 155 - 157 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Novel Data Embedding Method Using Adaptive Pixel Pair Matching |
Résumé:
This paper proposes a new data-hiding method based on pixel pair matching (PPM). The basic idea of PPM is to use the values of pixel pair as a reference coordinate, and search a coordinate in the neighborhood set of this pixel pair according to a given message digit. The pixel pair is then replaced by the searched coordinate to conceal the digit. Exploiting modification direction (EMD) and diamond encoding (DE) are two data-hiding methods proposed recently based on PPM. The maximum capacity of EMD is 1.161 bpp and DE extends the payload of EMD by embedding digits in a larger notational system. The proposed method offers lower distortion than DE by providing more compact neighborhood sets and allowing embedded digits in any notational system. Compared with the optimal pixel adjustment process (OPAP) method, the proposed method always has lower distortion for various payloads. Experimental results reveal that the proposed method not only provides better performance than those of OPAP and DE, but also is secure under the detection of some well-known steganalysis techniques. |
| Auteurs: Hong, W.;Chen, T.-S.; |
| Apparue dans: IEEE Transactions on Information Forensics and Security |
| Date publication: 02.-2012, volume: 7, issue:1, pages: 176 - 184 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Novel Extraction Method and Compact Model for the Steepness Estimation of FDSOI TFET Lateral Junction |
Résumé:
There are several techniques for junction profiling available in literature, yet none of them are practically suitable for the accurate determination of the lateral junction steepness in TFET devices, which is the most important parameter influencing TFET performance. In this work, a simple physics-based compact analytical model has been developed for the junction steepness as a function of the doping concentration and the maximum electric field at the junction. Using the underlying physics, we report a novel yet simple method to estimate the lateral junction steepness using only the –  measurements on a  tunnel diode test structure fabricated on the same wafer as the TFET with common process steps. Assuming that doping concentration, Si thin-film thickness, and buried-oxide thickness are known from the fabrication process, this algorithm uses the maximum electric field extracted from the – measurements and applies the analytical model to estimate the junction steepness. It has been observed that the estimations based on this method have a maximum deviation of sub-0.2 nm/decade from the actual junction steepness of the investigated devices. |
| Auteurs: Dan, S. S.;Biswas, A.;Royer, C. L.;Grabinski, W.;Ionescu, A. M.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 140 - 142 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Novel Hierarchical Bayesian Approach for Sparse Semisupervised Hyperspectral Unmixing |
Résumé:
In this paper the problem of semisupervised hyperspectral unmixing is considered. More specifically, the unmixing process is formulated as a linear regression problem, where the abundance's physical constraints are taken into account. Based on this formulation, a novel hierarchical Bayesian model is proposed and suitable priors are selected for the model parameters such that, on the one hand, they ensure the nonnegativity of the abundances, while on the other hand they favor sparse solutions for the abundances' vector. Performing Bayesian inference based on the proposed hierarchical Bayesian model, a new low-complexity iterative method is derived, and its connection with Gibbs sampling and variational Bayesian inference is highlighted. Experimental results on both synthetic and real hyperspectral data illustrate that the proposed method converges fast, favors sparsity in the abundances' vector, and offers improved estimation accuracy compared to other related methods. |
| Auteurs: Themelis, K. E.;Rontogiannis, A. A.;Koutroumbas, K. D.; |
| Apparue dans: IEEE Transactions on Signal Processing |
| Date publication: 02.-2012, volume: 60, issue:2, pages: 585 - 599 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Novel Large-Scale Digital Forensics Service Platform for Internet Videos |
Résumé:
The increasing transmission of illegal videos over the Internet imposes the needs to develop large-scale digital video forensics systems for prosecuting and deterring digital crimes in the Internet. In this paper, we propose, design, and implement a novel large-scale Digital Forensics Service Platform (DFSP) that can effectively detect illegal content from Internet videos. More specifically, we propose a distributed architecture by taking advantage of Content Delivery Network (CDN) to improve scalability, which can process enormous number of Internet videos in real time. We propose CDN-based Resource-Aware Scheduling (CRAS) algorithm, which schedules the tasks efficiently in the DFSP according to resource parameters, such as delay and computation load. We deploy the DFSP system in the Internet, which integrates the CDN-based distributed architecture and CRAS algorithm with a large-scale video detection algorithm, and evaluate the deployed system. Our evaluation results demonstrate the effectiveness of the platform. |
| Auteurs: Yin, H.;Hui, W.;Li, H.;Lin, C.;Zhu, W.; |
| Apparue dans: IEEE Transactions on Multimedia |
| Date publication: 02.-2012, volume: 14, issue:1, pages: 178 - 186 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A novel optimization based method for separation of periodic signals |
Résumé:
In the present paper a new method is proposed for separating the individual periodic components of a mixed signal. The method is capable to extract not only a harmonic but an anharmonic signal component from the mixture. To achieve this, the component is extracted by a FIR narrowband filter, which can modulate the output harmonic signal by an appropriate time-shift function. The search for this function is based on the minimization of a functional, which is calculated as the sum of the unsigned differences of the separated signal in a certain time window. The theoretical basis of this optimization method is that the functional above has global minimum if the separation is complete. The introduced tests show that the proposed method is more robust than the matrix algebraic separation (MAS) system in the case of a slightly frequency-modulated test signal. |
| Auteurs: Tamás Kovács |
| Apparue dans: Digital Signal Processing |
| Date publication: 02.-2012 |
| Editeur: Elsevier B.V. |
| Document complet vers site de l'éditeur |
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|
| » A Novel Rotor Configuration and Experimental Verification of Interior PM Synchronous Motor for High-Speed Applications |
Résumé:
On account of high efficiency and high power density, permanent-magnet synchronous motors (PMSMs) are mainly applied to a high-speed machine. Especially, because of relatively easy magnetic circuit design and control, a surface-mounted PMSM of them is adopted in almost the entire high-speed applications. However, the surface-mounted PMSM has some weak points due to a sleeve, which is nonmagnetic steel used in order to maintain the mechanical integrity of a rotor assembly in high-speed rotation. The sleeve causes additional eddy current loss in the rotor besides permanent magnet and increases not only magnetic air-gap length but manufacturing costs by raw material purchase and shrink fitting. Thus, in this paper, a new rotor shape for a high-speed interior permanent-magnet synchronous motor (IPMSM) is presented in order to resolve the faults of the surface-mounted PMSM. Moreover, the amount of permanent magnet employed in the IPMSM is decreased by approximately 53% than that of the surface-mounted PMSM. Except for the rotor configuration, all design conditions of the IPMSM are identical compared with the surface-mounted PMSM. Finally, the IPMSM is fabricated, and its superiority and reliability in high-speed operation are verified by test. |
| Auteurs: Kim, S.-I.;Kim, Y.-K.;Lee, G.-H.;Hong, J.-P.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 843 - 846 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Novel Sinusoidal Pressure Generator Based on Magnetic Liquid |
Résumé:
A novel sinusoidal pressure generator with low frequency(0.1 Hz  100 Hz) based on magnetic liquid is proposed in this paper. Magnetic liquid possess both magnetism characteristic of solid magnetic material and fluidity of the liquid. The magnetic liquid acts as a reciprocating piston, when it is placed in the alternating magnetic field. Based on this, we devised a setup use of magnetic liquid to generate micro differential pressure, which varies sinusoidal and has the same frequency with the exciting current. The relation between input current and output pressure was also analyzed in this paper. Magnetic field and magnetic force is calculated. Meanwhile, the experimental platform was built for testing the performance of the setup and some experimental is performed. Both the theoretical analysis and the experiment results prove that this kind of new sinusoidal pressure generator satisfies the design demand. |
| Auteurs: Yang, W.;Wang, F.;Yang, Q.;Zhang, W.;Zhang, B.;Wang, Y.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 575 - 578 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Novel Slow-Wave Structure—Folded Rectangular Groove Waveguide for Millimeter-Wave TWT |
Résumé:
A novel slow-wave structure (SWS) called the folded rectangular groove guide, its electromagnetic characteristics, and the beam-wave interaction are presented. This structure, evolved from a conventional rectangular groove guide by bending the groove along its longitudinal direction, can operate with the sheet electron beam or the circular electron beam. From our calculations, this SWS possesses larger interaction impedance and lower ohmic loss than those of a folded rectangular waveguide with the same size. This circuit can produce output power of over 260 W with a sheet electron beam in the 3-dB bandwidth range of 88.5.5–98.5 GHz when the cathode voltage and beam current are set to 19.45 kV and 150 mA, respectively, whereas the folded rectangular waveguide can produce output power over 245 W in the 3-dB bandwidth range of 84–89 GHz. |
| Auteurs: Tian, Y.;Yue, L.;Xu, J.;Wang, W.;Wei, Y.;Gong, Y.;Feng, J.; |
| Apparue dans: IEEE Transactions on Electron Devices |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 510 - 515 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Novel Thermoelectric and Capacitive Power Sensor With Improved Dynamic Range Based on GaAs MMIC Technology |
Résumé:
A novel thermoelectric and capacitive power sensor with improved dynamic range based on GaAs monolithic microwave integrated circuit (MMIC) technology is proposed in this letter. This power sensor is designed and fabricated using GaAs MMIC process and MEMS technology. A MEMS cantilever beam is introduced and monolithically integrated as a capacitive power sensor to improve the overload capacity and the dynamic range at the cost of sensitivity. The measurement results verify the role of the MEMS cantilever beam. Another advantage of this power sensor consists in compatibility with MMIC devices and other planar connecting circuit structures with zero dc power consumption. |
| Auteurs: De Bo, W.;Ping, L. X.;Tong, L.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 269 - 271 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
» A Novel Wide-Temperature-Range, 3.9 ppm/  C CMOS Bandgap Reference Circuit |
Résumé:
This paper presents an innovative CMOS Bandgap Reference Generator topology that leads to an improved curvature compensation method over a very wide temperature range. The proposed design was implemented in a standard 0.35 CMOS process. The compensation is performed by using only poly-silicon resistors. This is achieved by using a second Op-amp that generates a CTAT current, which is subsequently used to enhance the curvature compensation method. The performance of the circuit was verified experimentally. Measured results have shown temperature coefficients as low as 3.9  over a temperature range of 165 (  to 150 ) and temperature coefficients as low as 13.7 over an extended temperature range of 200 (  to 150 ). In addition the circuit demonstrated very good line regulation performance for a broad range of supply voltages. The measured line regulation at room temperature is 0.039% V. |
| Auteurs: Andreou, C. M.;Koudounas, S.;Georgiou, J.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 574 - 581 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Numerical Study of Line-Edge Roughness Scattering in Graphene Nanoribbons |
Résumé:
The role of line-edge roughness scattering on the electronic properties of graphene nanoribbons is numerically investigated. The nonequilibrium Green function formalism, along with an atomistic tight-binding model, is employed. Our results indicate that, depending on the geometrical and roughness parameters, the transport of carriers can be in the diffusive or localization regime. We extract the mean free path and the localization length, which characterize the diffusive and localization regimes, respectively. In the diffusive regime, the conductance linearly decreases with length, whereas in the localization regime, it exponentially decreases with length. However, as the localization length depends on the carrier energy, an effective transport gap in this regime can be defined. This gap is evaluated as a function of the geometrical and roughness parameters, and its impact on the device performance is discussed. |
| Auteurs: Yazdanpanah, A.;Pourfath, M.;Fathipour, M.;Kosina, H.;Selberherr, S.; |
| Apparue dans: IEEE Transactions on Electron Devices |
| Date publication: 02.-2012, volume: 59, issue:2, pages: 433 - 440 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Parameterized Mesh Generation and Refinement Method for Finite Element Parameter Sweeping Analysis of Electromagnetic Devices |
Résumé:
A parameterized mesh generation and refinement method is presented for parameter sweeping analysis of electromagnetic designs. The advantages of the method are distinct in that the method is remeshing-free, thus it can significantly reduce the numerical simulation time during the finite element analysis (FEA) process. The refinement procedure is accomplished in an adaptive manner to concentrate the mesh vertices to regions with large solution variations. A high quality mesh can be obtained and kept by using this method with triangular finite elements. An example of parameter sweeping for optimal electric motor design is given to showcase the effectiveness of the proposed method. |
| Auteurs: Zhao, Y.;Niu, S.;Ho, S. L.;Fu, W. N.;Zhu, J.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 239 - 242 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Particle Swarm Optimization Algorithm With Novel Expected Fitness Evaluation for Robust Optimization Problems |
Résumé:
In this paper, an improved particle swarm optimization (PSO) algorithm for robust optimization problems is proposed. The new algorithm, named robust particle swarm optimization (RPSO), deeps basic concepts of the PSO, results in dynamic determination of the robust optimal solution by using a  -quadrant-longest-distance expected fitness evaluation strategy in  -D space, and obtains robustness against the perturbation of design variables. The efficiency and advantages of the proposed algorithm are verified by the application to a mathematical function and a practical electromagnetic problem. |
| Auteurs: Luan, F.;Choi, J.-H.;Jung, H.-K.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 331 - 334 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A perfect storm of planetary proportions |
Résumé:
How a solar superstorm could take down power grids everywhere. — L uminous fingers of intense red, green, and violet light flicker and pulse across the northern and southern skies like a vast cosmic conflagration. Within minutes, millions of people are tweeting, texting, and blogging about the wondrous sight. But then the sky turns a deep blood red, and fascination turns to panic. Linked to the celestial spectacle are enormous fluctuations ofthe magnetic field in Earth's magnetosphere, which are causing immense flows of electric current in the upper atmosphere over much of the planet. Those huge currents disturb Earth's normally quiescent magnetic field, which in turn induces surges of current in electrical, telecommunications, and other networks across entire continents. Streetlights flicker out; electricity is lost. A massive planetary blackout has occurred, leaving vast swaths of North and South America, Europe, Australia, and Asia without power. |
| Auteurs: Kappenman, J.; |
| Apparue dans: IEEE Spectrum |
| Date publication: 02.-2012, volume: 49, issue:2, pages: 26 - 31 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Position Detection Strategy for Sensorless Surface Mounted Permanent Magnet Motors at Low Speed Using Transient Finite-Element Analysis |
Résumé:
A novel solution for sensorless starting of conventional surface mounted PM motors is proposed. The strategy of the proposed scheme is to creatively formulate a combination of electromagnetic field with transient finite element method (FEM). The proposed solution is an improvement over and above conventional methods in that it is based on rotor position detection at zero speed with high frequency signal injection and back EMF detection. Previous researches tend to consider the induced signal from different winding terminals independently. The proposed methodology however exploits the induced voltage signals from two of the motor winding terminals, using the third terminal as the signal injection point. The strategy also eliminates the process of polarity tests. The relationship between the dependency of induced signals and the rotor position angle is summarized, and a simple motor starting scheme is proposed. Effects arising from the transient characteristics of the injected/induced signals are fully addressed using FEM. |
| Auteurs: Wang, Z.;Niu, S.;Ho, S. L.;Fu, W. N.;Zhu, J.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 1003 - 1006 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Power-Balanced Time-Stepping Finite Element Method for Transient Magnetic Field Computation |
Résumé:
Conventional transient finite-element methods (FEM) of magnetic field and electric circuit coupled problems often result in unbalanced power computation. In the worst case, the output power may be even miscomputed to be larger than the input power which violates all fundamental laws of physics. Eddy-current loss computation in laminated iron cores is usually carried out in a postprocessing algorithm, and thus the effect of eddy-current on both the system equations and other physical quantities cannot be included conveniently. This paper studies the power-balanced computation in FEM from two important aspects, which are, namely, the time integration algorithms and the inclusion of eddy-current loss in laminated iron cores of the system equations. A novel approach is presented, which retains the power balance property (i.e., all power, including the losses, are considered and balanced in both input and output) in the time integration process, to include the eddy-current loss effect in the FEM system equations. It also insures the solution is stable. Consequently, the input power, losses, and output power of the electromagnetic systems are balanced, and the accuracy of the solutions, especially the efficiency, is guaranteed. A numerical experiment is carried out on a laminated transformer to verify the accuracy of the proposed method. |
| Auteurs: Ho, S. L.;Niu, S.;Fu, W. N.;Zhu, J.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 291 - 294 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Power-Efficient Receiver Architecture Employing Bias-Current-Shared RF and Baseband With Merged Supply Voltage Domains and 1/f Noise Reduction |
Résumé:
A power-efficient quadrature receiver employing a down-converter that uses a passive current-commutating mixer for frequency translation is presented. The architecture uses bias-current sharing between the RF and baseband stages while making the full supply voltage available to either stage. An input transconductor, realized using a differential common-source stage, converts the RF signal into a current, while baseband amplification is achieved using a transimpedance amplifier. Active noise shaping networks are implemented for reducing low-frequency noise at the output that can arise from the RF and baseband transconductors. Linearity is enhanced by synthesizing a nonlinear gain in the transimpedance amplifier to compensate for baseband compression. The design includes variable gain capability. An on-chip divider is employed to synthesize quadrature LO signals. Noise and linearity performance of the core down-converter is analyzed. The receiver is implemented in a 0.18 CMOS technology. The prototype achieves a maximum conversion gain of 44.5 dB, NF of 4.3 dB, in-channel OIP3 of 20 dBV while consuming 2.2 mA in each of the quadrature paths from a 1.8 V supply. This performance is achieved without the use of integrated inductors, which allows for a small die area of 0.5 mm  . |
| Auteurs: Ghosh, D.;Gharpurey, R.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 381 - 391 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
» A Probabilistic Model of ) Visual Cryptography Scheme With Dynamic Group |
Résumé:
The $) visual cryptography (VC) is a secret sharing scheme where a secret image is encoded into transparencies, and the stacking of any  out of transparencies reveals the secret image. The stacking of  or fewer transparencies is unable to extract any information about the secret. We discuss the additions and deletions of users in a dynamic user group. To reduce the overhead of generating and distributing transparencies in user changes, this paper proposes a VC scheme with unlimited based on the probabilistic model. The proposed scheme allows to change dynamically in order to include new transparencies without regenerating and redistributing the original transparencies. Specifically, an extended VC scheme based on basis matrices and a probabilistic model is proposed. An equation is derived from the fundamental definitions of the VC scheme, and then the $) VC scheme achieving maximal contrast can be designed by using the derived equation. The maximal contrasts with  to  are explicitly solved in this paper. |
| Auteurs: Lin, S.-J.;Chung, W.-H.; |
| Apparue dans: IEEE Transactions on Information Forensics and Security |
| Date publication: 02.-2012, volume: 7, issue:1, pages: 197 - 207 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A PWM Harmonics Elimination Method in Simultaneous Estimation of Magnetic Field and Displacements in Bearingless Induction Motors |
Résumé:
This paper introduces a novel method for simultaneous estimation of the revolving magnetic field and rotor radial displacements in bearingless induction motors. Four auxiliary windings, i.e., search coils, are wound around the stator teeth in an induction-type bearingless motor. The coils are connected to a high-frequency voltage source. The middle-point voltages between two search coils are processed with simple analog circuits to obtain radial rotor displacements. These middle-point voltages are affected by harmonic voltages generated by a general-purpose PWM inverter connected to motor terminals. Two methods of noise elimination are proposed and tested. The theoretical analysis and the successful experimental results validate the proposed approach. |
| Auteurs: Chiba, A.;Santisteban, J. A.; |
| Apparue dans: IEEE Transactions on Industry Applications |
| Date publication: 02.-2012, volume: 48, issue:1, pages: 124 - 131 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Recursive Sparsification of the Inverse Hodge Matrix |
Résumé:
When applying the theory of differential forms to solve wave propagation problems in time domain, we must solve at each time step a sparse linear system defined by the insertion of constitutive laws via the mass matrices. In this paper, we describe a recursive technique to efficiently calculate the approximated inverse of Hodge matrix. The fundamental idea is to recursively decompose the mass matrix in to a decreasing size sequence of matrices using block matrix inversion. During the recomposition process, the matrix is sparsified. Numerical results are presented to validate our approach. |
| Auteurs: Moura, A. S.;Saldanha, R. R.;Silva, E. J.;Lisboa, A. C.;Facco, W. G.;Facco, N. Z.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 611 - 614 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Review of Ammonia-Based Thermochemical Energy Storage for Concentrating Solar Power |
Résumé:
The development of a thermochemical energy storage system based on ammonia, for use with concentrating solar power is discussed in this paper. This is one of a number of storage options for concentrating solar power, including molten-salt storage, which is already operating commercially. The ammonia storage development has involved prototype solar receiver/reactors operated in conjunction with a 20-m dish concentrator, as well as closed-loop storage demonstrations. An ongoing computational study deals with the performance of an ammonia receiver for a 489-m dish concentrator. The ammonia storage system could employ industry-standard ammonia synthesis converters for superheated steam production. A standard 1500 t/day ammonia synthesis reactor would suffice for a 10-MW  baseload plant with 330 large 489-m dishes. At this stage, an updated economic assessment of the system would be valuable. |
| Auteurs: Dunn, R.;Lovegrove, K.;Burgess, G.; |
| Apparue dans: Proceedings of the IEEE |
| Date publication: 02.-2012, volume: 100, issue:2, pages: 391 - 400 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Review of Nonimaging Stand-Off Concealed Threat Detection with Millimeter-Wave Radar [Application Notes] |
Résumé:
There is now, more than ever before, a need for technologies that enable the screening of people from a distance. A wide variety of weapons can be easily concealed under clothing and carried into crowded public sites to target national infrastructure, spread fear, and infl ict mass murder and casualties. The most feared and devastating terrorist weapon is the suicide bomb or person borne improvised explosive device (PBIED). Such devices are relatively simple to conceal on the body, and successful detection is required at considerable distance or stand-off range before the bomber reaches the target area. |
| Auteurs: Harmer, S.;Bowring, N.;Andrews, D.;Rezgui, N.;Southgate, M.;Smith, S.; |
| Apparue dans: IEEE Microwave Magazine |
| Date publication: 02.-2012, volume: 13, issue:1, pages: 160 - 167 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Robust Adaptive Control Strategy of Active Power Filters for Power-Factor Correction, Harmonic Compensation, and Balancing of Nonlinear Loads |
Résumé:
This paper introduces a robust adaptive control strategy of shunt active power filters (SAPF) for power-factor correction, harmonic compensation, and balancing of nonlinear loads. The proposed control scheme is implemented without load harmonic detection. The compensation constraints are obtained by regulating indirectly the currents of the power mains. The reference currents of are generated by the dc-link voltage controller based on the active power balance of system. They are aligned to the phase angle of the power mains voltage vector, by using a phase-locked loop system. The current control strategy is implemented by an adaptive pole-placement control strategy integrated to a variable structure control scheme. This control scheme uses the internal model principle of reference currents for achieving the zero steady-state tracking error. Experimental results are shown for determining the effectiveness of an -proposed control system. |
| Auteurs: de Araujo Ribeiro, R.L.;de Azevedo, C.C.;de Sousa, R.M.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 718 - 730 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Robust Physical Unclonable Function With Enhanced Challenge-Response Set |
Résumé:
A Physical Unclonable Function (PUF) is a promising solution to many security issues due its ability to generate a die-unique identifier that can resist cloning attempts as well as physical tampering. However, the efficiency of a PUF depends on its implementation cost, its reliability, its resiliency to attacks, and the amount of entropy in it. PUF entropy is used to construct cryptographic keys, chip identifiers, or challenge-response pairs (CRPs) in a chip authentication mechanism. The amount of entropy in a PUF is limited by the circuit resources available to build a PUF. As a result, generating longer keys or larger sets of CRPs may increase PUF circuit cost. We address this limitation in a PUF by proposing an identity-mapping function that expands the set of CRPs of a ring-oscillator PUF (RO-PUF) with low area cost. The CRPs generated through this function exhibit strong PUF qualities in terms of uniqueness and reliability. To introduce the identity-mapping function, we formulate a novel PUF system model that uncouples PUF measurement from PUF identifier formation. We show the enhanced CRP generation capability of the new function using a statistical hypothesis test. An implementation of our technique on a low-cost FPGA platform shows at least 2 times savings in area compared to the traditional RO-PUF. The proposed technique is validated using a population of 125 chips, and its reliability over varying environmental conditions is shown. |
| Auteurs: Maiti, A.;Kim, I.;Schaumont, P.; |
| Apparue dans: IEEE Transactions on Information Forensics and Security |
| Date publication: 02.-2012, volume: 7, issue:1, pages: 333 - 345 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Saturated Light Correction Method for DMSP/OLS Nighttime Satellite Imagery |
Résumé:
Several studies have clarified that electric power consumption can be estimated from the Defense Meteorological Satellite Program/Operational Linescan System (DMSP/OLS) stable light imagery. As digital numbers (DNs) of stable light images are often saturated in the center of city areas, we developed a saturated light correction method for the DMSP/OLS stable light image using the nighttime radiance calibration image of the DMSP/OLS. The comparison between the nonsaturated part of the stable light image for 1999 and the radiance calibration image for 1996–1997 in major areas of Japan showed a strong linear correlation $) between the DNs of both images. Saturated DNs of the stable light image could therefore be corrected based on the correlation equation between the two images. To evaluate the new saturated light correction method, a regression analysis is performed between statistic data of electric power consumption from lighting and the cumulative DNs of the stable light image before and after correcting for the saturation effects by the new method, in comparison to the conventional method, which is, the cubic regression equation method. The results show a stronger improvement in the determination coefficient with the new saturated light correction method $) than with the conventional method $) from the initial correlation with the uncorrected data $) . The new method proves therefore to be very efficient for saturated light correction. |
| Auteurs: Letu, H.;Hara, M.;Tana, G.;Nishio, F.; |
| Apparue dans: IEEE Transactions on Geoscience and Remote Sensing |
| Date publication: 02.-2012, volume: 50, issue:2, pages: 389 - 396 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Scalable Distributed Architecture for Intelligent Vision System |
Résumé:
The complexity of intelligent computer vision systems demands novel system architectures that are capable of integrating various computer vision algorithms into a working system with high scalability. The real-time applications of human-centered computing are based on multiple cameras in current systems, which require a transparent distributed architecture. This paper presents an application-oriented service share model for the generalization of vision processing. Based on the model, a vision system architecture is presented that can readily integrate computer vision processing and make application modules share services and exchange messages transparently. The architecture provides a standard interface for loading various modules and a mechanism for modules to acquire inputs and publish processing results that can be used as inputs by others. Using this architecture, a system can load specific applications without considering the common low-layer data processing. We have implemented a prototype vision system based on the proposed architecture. The latency performance and 3-D track function were tested with the prototype system. The architecture is scalable and open, so it will be useful for supporting the development of an intelligent vision system, as well as a distributed sensor system. |
| Auteurs: Wang, G.;Tao, L.;Di, H.;Ye, X.;Shi, Y.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 91 - 99 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A self-seeded tunable multiwavelength erbium-doped fiber ring laser with fiber bending scheme |
Résumé:
Highlights? A new tunable multiwavelength fiber laser is implemented with a fiber bending scheme. ? The wavelength tuning is controlled by bending a section of fiber in the laser cavity. ? Tuning range for single wavelength lasing is 20 nm. |
| Auteurs: A new tunable multiwavelength fiber laser is proposed. Such a laser contains a homogeneous and inhomogeneous broadening media, i.e., a Fabry-Perót laser diode and an erbium-doped fiber amplifier, in the laser cavity. The Fabry-Perót laser diode is us |
| Apparue dans: Optical Fiber Technology |
| Date publication: 02.-2012 |
| Editeur: Elsevier B.V. |
| Document complet vers site de l'éditeur |
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|
| » A Semitransparency-Based Optical-Flow Method With a Point Trajectory Model for Particle-Like Video |
Résumé:
This paper proposes a new semitransparency-based optical-flow model with a point trajectory (PT) model for particle-like video. Previous optical-flow models have used ranging from image brightness constancy to image brightness change models as constraints. However, two important issues remain unsolved. The first is how to track/match a semitransparent object with a very large displacement between frames. Such moving objects with different shapes and sizes in an outdoor scene move against a complicated background. Second, due to semitransparency, the image intensity between frames can also violate a previous image brightness-based optical-flow model. Thus, we propose a two-step optimization for the optical-flow estimation model for a moving semitransparent object, i.e., particle. In the first step, a rough optical flow between particles is estimated by a new alpha constancy constraint that is based on an image generation model of semitransparency. In the second step, the optical flow of a particle with a continuous trajectory in a definite temporal interval based on a PT model can be refined. Many experiments using various falling-snow and foggy scenes with multiple moving vehicles show the significant improvement of the optical flow compared with a previous optical-flow model. |
| Auteurs: Sakaino, H.; |
| Apparue dans: IEEE Transactions on Image Processing |
| Date publication: 02.-2012, volume: 21, issue:2, pages: 441 - 450 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Sensitivity Analysis Method for Equivalent Parameter Extraction of Transient Magnetic Field With Internal Circuits |
Résumé:
A sensitivity analysis method for the equivalent parameter extraction of transient magnetic field problems with internally coupled circuits is presented. In contrast to conventional methods using physical meaning and physical relationships for parameter extraction, this method is based on a collection of mathematical system equations which include transient magnetic field equations and internal circuit equations. The extracted parameters include the collective effects of eddy currents, internal circuits, and mechanical motion. Compared with previous sensitivity analysis methods which extract only the equivalent inductance, the proposed algorithm extracts also the equivalent resistance. A laminated transformer with internal circuit is reported to validate and showcase the proposed method. |
| Auteurs: Ho, S. L.;Niu, S.;Fu, W. N.;Zhu, J.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 295 - 298 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Shift-Tolerant Dissimilarity Measure for Surface Defect Detection |
Résumé:
Template matching has been widely used in image processing for visual inspection of complicated, patterned surfaces. The currently existing methods such as golden template matching and normalized cross correlation are very sensitive to the displacement even the object under test is carefully aligned with respect to the template. This paper proposes a dissimilarity measure based on the optical-flow technique for surface defect detection, and aims at light-emitting diode (LED) wafer die inspection. The dissimilarity measure of each pixel derived from the optical flow field does not represent the true translation distance, but is reliable enough to indicate the degree of difference between an image pair. It is well tolerated to misalignment and random product variation. The integral image technique is applied to replace the sum operations in optical flow computation, and speeds up the intensive computation. We also point out the pitfall of the Lucas–Kanade optical flow when it is applied for defect detection, and propose a swapping process to tackle the problem. The experiment on LED wafer dies has shown that the proposed method can achieve a 100% recognition rate based on a test set of 357 die images. |
| Auteurs: Tsai, D.-M.;Chiang, I.-Y.;Tsai, Y.-H.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 128 - 137 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Simple and Robust Feature Point Matching Algorithm Based on Restricted Spatial Order Constraints for Aerial Image Registration |
Résumé:
Accurate point matching is a critical and challenging process in feature-based image registration. In this paper, a simple and robust feature point matching algorithm, called Restricted Spatial Order Constraints (RSOC), is proposed to remove outliers for registering aerial images with monotonous backgrounds, similar patterns, low overlapping areas, and large affine transformation. In RSOC, both local structure and global information are considered. Based on adjacent spatial order, an affine invariant descriptor is defined, and point matching is formulated as an optimization problem. A graph matching method is used to solve it and yields two matched graphs with a minimum global transformation error. In order to eliminate dubious matches, a filtering strategy is designed. The strategy integrates two-way spatial order constraints and two decision criteria restrictions, i.e., the stability and accuracy of transformation error. Twenty-nine pairs of optical and Synthetic Aperture Radar (SAR) aerial images are utilized to evaluate the performance. Compared with RANdom SAmple Consensus (RANSAC), Graph Transformation Matching (GTM), and Spatial Order Constraints (SOC), RSOC obtained the highest precision and stability. |
| Auteurs: Liu, Z.;An, J.;Jing, Y.; |
| Apparue dans: IEEE Transactions on Geoscience and Remote Sensing |
| Date publication: 02.-2012, volume: 50, issue:2, pages: 514 - 527 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Simple Sag Generator Using SSRs |
Résumé:
Power line voltage sags are among the most frequent and costly power quality problems. Most equipment must be designed such that they can tolerate voltage sags (within limits defined according to some standards). Furthermore, some equipment must continue proper operation even under extreme sag conditions (critical loads); this property often may not be accommodated inside the device itself, and sag-compensating power conditioners have been developed for such purposes. While, in practice, voltage sags are not wanted, generating sags becomes necessary for the purpose of experimentally verifying the performances of the equipment (both the equipment under sag condition and the sag-compensating power conditioner) under sag conditions. In this paper, a simple and economical, yet highly performing, sag generator is developed, its design is discussed, and its feasibility is demonstrated by experiments. The proposed solid-state relay (a semiconductor power module of triac characteristics) and variable transformer (variac)-based sag generator is built for three-phase 10-kVA ratings, and balanced/imbalanced voltage sags are demonstrated in the laboratory. The performance under resistive, inductive, and nonlinear loads is evaluated, and finally, the utilization of the sag generator in the test of a series-active-filter-based power quality conditioner is demonstrated. The proposed approach provides a very simple, yet highly effective, solution for voltage sag generation. |
| Auteurs: Senturk, O. S.;Hava, A. M.; |
| Apparue dans: IEEE Transactions on Industry Applications |
| Date publication: 02.-2012, volume: 48, issue:1, pages: 172 - 180 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Soft Switching Three-phase Current-fed Bidirectional DC-DC Converter With High Efficiency Over a Wide Input Voltage Range |
Résumé:
In this paper, a three-phase current-fed dual-active-bridge (DAB) bidirectional DC-DC converter is presented. Compared to the voltage source DAB converter, the proposed converter allows low RMS current and maintains zero voltage switching (ZVS) in the whole operating range by keeping the ratio between primary side and secondary side DC-link voltage constant, leading to high efficient energy conversion over a wide input voltage range. In addition, the ZVS conditions can be maintained using small DC inductors and the input current ripple still remains small because of high DC inductor current ripples being alleviated by three-phase interleaving structure. Furthermore, the proposed topology with Y-Y connected transformers is proven to have better current sharing capability compared with other three-phase topologies with different transformer connections. The operation mode analysis, soft switching conditions, and hardware design guidelines are derived in this paper. A 6-kW hardware prototype with input voltage range of 24~48 V and rated 288 V output voltage is developed and tested in the laboratory. The experimental results verified that the proposed converter could maintain high efficiency over a wide input voltage and power range. |
| Auteurs: Zhan Wang;Hui Li; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 669 - 684 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A soft touch [Tools & Toys] |
Résumé:
Telikin's new touchscreen desktop computer targets seniors—and runs Linux |
| Auteurs: Teasley, H.; |
| Apparue dans: IEEE Spectrum |
| Date publication: 02.-2012, volume: 49, issue:2, pages: 22 - 23 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Solution to the Unit Commitment Problem Using Imperialistic Competition Algorithm |
Résumé:
This paper presents a new approach via a new evolutionary algorithm known as imperialistic competition algorithm (ICA) to solve the unit commitment (UC) problem. In ICA the initial population individuals (countries) are in two types: imperialists and colonies that all together form some empires. Imperialistic competitions among these empires converge to a state in which there exists only one empire. In the proposed ICA for the UC problem, the scheduling variables are coded as integers; therefore, the minimum up/down-time constraints can be handled directly. A new method for initializing the countries is proposed. To verify the performance of the proposed algorithm, it is applied to systems with number of generating units in range of 10 up to 100 in one-day scheduling period. |
| Auteurs: Moghimi Hadji, M.;Vahidi, B.; |
| Apparue dans: IEEE Transactions on Power Systems |
| Date publication: 02.-2012, volume: 27, issue:1, pages: 117 - 124 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Spectrally-Accurate FVTD Technique for Complicated Amplification and Reconfigurable Filtering EMC Devices |
Résumé:
The consistent and computationally economical analysis of demanding amplification and filtering structures is introduced in this paper via a new spectrally-precise finite-volume time-domain algorithm. Combining a family of spatial derivative approximators with controllable accuracy in general curvilinear coordinates, the proposed method employs a fully conservative field flux formulation to derive electromagnetic quantities in areas with fine structural details. Moreover, the resulting 3-D operators assign the appropriate weight to each spatial stencil at arbitrary media interfaces, while for periodic components the domain is systematically divided to a number of nonoverlapping subdomains. Numerical results from various real-world configurations verify our technique and reveal its universality. |
| Auteurs: Kantartzis, N. V.;Assimonis, S. D.;Lalas, A. X.;Scott, J. B.;Antonopoulos, C. S.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 383 - 386 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Statistical Method for 2-D Facial Landmarking |
Résumé:
Many facial-analysis approaches rely on robust and accurate automatic facial landmarking to correctly function. In this paper, we describe a statistical method for automatic facial-landmark localization. Our landmarking relies on a parsimonious mixture model of Gabor wavelet features, computed in coarse-to-fine fashion and complemented with a shape prior. We assess the accuracy and the robustness of the proposed approach in extensive cross-database conditions conducted on four face data sets (Face Recognition Grand Challenge, Cohn–Kanade, Bosphorus, and BioID). Our method has 99.33% accuracy on the Bosphorus database and 97.62% accuracy on the BioID database on the average, which improves the state of the art. We show that the method is not significantly affected by low-resolution images, small rotations, facial expressions, and natural occlusions such as beard and mustache. We further test the goodness of the landmarks in a facial expression recognition application and report landmarking-induced improvement over baseline on two separate databases for video-based expression recognition (Cohn–Kanade and BU-4DFE). |
| Auteurs: Dibeklioglu, H.;Salah, A. A.;Gevers, T.; |
| Apparue dans: IEEE Transactions on Image Processing |
| Date publication: 02.-2012, volume: 21, issue:2, pages: 844 - 858 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Stochastic Collocation Method Combined With a Reduced Basis Method to Compute Uncertainties in Numerical Dosimetry |
Résumé:
A reduced basis method is introduced to deal with a stochastic problem in a numerical dosimetry application in which the field solutions are computed using an iterative solver. More precisely, the computations already performed are used to build an initial guess for the iterative solver. It is shown that this approach significantly reduces the computational cost. |
| Auteurs: Drissaoui, M. A.;Lanteri, S.;Leveque, P.;Musy, F.;Nicolas, L.;Perrussel, R.;Voyer, D.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 563 - 566 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Survey on the Electrification of Transportation in a Smart Grid Environment |
Résumé:
Economics and environmental incentives, as well as advances in technology, are reshaping the traditional view of industrial systems. The anticipation of a large penetration of plug-in hybrid electric vehicles (PHEVs) and plug-in electric vehicles (PEVs) into the market brings up many technical problems that are highly related to industrial information technologies within the next ten years. There is a need for an in-depth understanding of the electrification of transportation in the industrial environment. It is important to consolidate the practical and the conceptual knowledge of industrial informatics in order to support the emerging electric vehicle (EV) technologies. This paper presents a comprehensive overview of the electrification of transportation in an industrial environment. In addition, it provides a comprehensive survey of the EVs in the field of industrial informatics systems, namely: 1) charging infrastructure and PHEV/PEV batteries; 2) intelligent energy management; 3) vehicle-to-grid; and 4) communication requirements. Moreover, this paper presents a future perspective of industrial information technologies to accelerate the market introduction and penetration of advanced electric drive vehicles. |
| Auteurs: Su, W.;Eichi, H. R.;Zeng, W.;Chow, M.-Y.; |
| Apparue dans: IEEE Transactions on Industrial Informatics |
| Date publication: 02.-2012, volume: 8, issue:1, pages: 1 - 10 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
» A Switchless,  -Band Bidirectional Transceiver in 0.12- m SiGe BiCMOS Technology |
Résumé:
A fully-integrated  -band (40–45 GHz) bidirectional transceiver is demonstrated in a 0.12- SiGe BiCMOS technology. The RF front-end design eliminates the need for transmit/receive switches by demonstrating a novel PA/LNA circuit. The transceiver has a transmit conversion gain of 35 dB with a 3-  bandwidth of 4 GHz. The OP1dB is 8.5 dBm and Psat is 9.5 dBm. The transceiver has a receive conversion gain of 34 dB with a 3- bandwidth of 3 GHz. The noise figure is 4.7 dB and OP1dB is  5 dBm at 43 GHz. The chip consumes 119.4 mW when transmitting and 54 mW when receiving, and overall chip size is 1.6 mm  0.8 mm including pads. To the author's knowledge, this work represents the first switchless millimeter-wave bidirectional transceiver in a CMOS or BiCMOS process. |
| Auteurs: Kim, J.;Buckwalter, J. F.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 368 - 380 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Symmetric-Rate, Extended-Reach 40 Gb/s CWDM-TDMA PON With Downstream and Upstream SOA-Raman Amplification |
Résumé:
We demonstrate an extended reach 60 km coarse wavelength division multiplexing (CWDM)-time division multiple access (TDMA) passive optical network (PON) with 40 Gb/s capacity for both down and upstream directions. The system leverages existing 10 Gb/s TDMA PON technologies and incorporates various subsystems such as volume manufacturable optical transmitters, a prototype 10 Gb/s burst-mode receiver, hybrid semiconductor optical amplifier-Raman amplifiers, and a cyclic CWDM multiplexer. We confirm that this 32-user system has sufficient power margin to accommodate 128 users. |
| Auteurs: Reichmann, K. C.;Iannone, P. P.;Brinton, C.;Nakagawa, J.;Cusick, T.;Kimber, E. M.;Doerr, C.;Buhl, L. L.;Cappuzzo, M.;Chen, E. Y.;Gomez, L.;Johnson, J.;Kanan, A. M.;Lentz, J.;Chang, Y. F.;Palsdottir, B.;Tokle, T.;Spiekman, L.; |
| Apparue dans: Journal of Lightwave Technology |
| Date publication: 02.-2012, volume: 30, issue:4, pages: 479 - 485 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Systematic Method for Constructing Feasible Solution to SCUC Problem With Analytical Feasibility Conditions |
Résumé:
Obtaining high-quality feasible solution is the core and the major difficulty in solving security-constrained unit commitment (SCUC) problems. This paper presents a systematic method for constructing feasible solutions to SCUC problem based on a group of analytical feasibility conditions. The feasibility check is performed based on the analytical necessary conditions such that most of infeasible UC states can be identified without solving LP problem. If a UC state is infeasible, it is adjusted with the possibly minimal operating cost increase based on the cost information. This UC adjusting issue is formulated as a zero-one programming problem and a branch and bound (B&B) method is established based on these feasibility conditions. Numerical testing is performed for a 31-bus system, an IEEE 24-bus system, and an IEEE 118-bus system. The testing results suggest that over 95% of infeasible UC states are identified by the analytical necessary conditions. The near-optimal feasible schedules for SCUC problem can be obtained efficiently by the proposed method. The feasible schedules obtained are compared with those obtained from mixed integer programming-based method in the IEEE 118-bus system. It is shown that the new method can produce competitive results in terms of solution quality and computational efficiency. |
| Auteurs: Wu, H.;Guan, X.;Zhai, Q.;Ye, H.; |
| Apparue dans: IEEE Transactions on Power Systems |
| Date publication: 02.-2012, volume: 27, issue:1, pages: 526 - 534 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A tale of two Neptunes |
Résumé:
The Canadian undersea observatory recovers from an outage, and its U.S. counterpart finally gets started. |
| Auteurs: Fairley, P.; |
| Apparue dans: IEEE Spectrum |
| Date publication: 02.-2012, volume: 49, issue:2, pages: 11 - 12 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Thermal Improvement Technique for the Phase Windings of Electrical Machines |
Résumé:
In electrical machines, a higher torque/force density can usually be achieved by increasing the current density in the windings. However, the resulting increase in copper losses leads to higher temperatures in the coils, particularly in the center of the slots where the thermal resistance to the ambient/cooling surfaces is highest. In this paper, a novel, simple technique is presented in which a higher thermal conductivity path between the center of the slot and the cooling arrangement is created, thus increasing the heat flow away from the slot center. A lumped-parameter thermal model is presented and used along with finite-element analysis to investigate the effectiveness of the proposed technique. The lumped-parameter model is also used for optimizing the high conductivity path for maximum air-gap shear stress and to obtain a compromise between the reduced slot area and the improved temperature distribution. Experimental validation is then presented to compare the predicted results with the measured results on a purposely built instrumented setup. |
| Auteurs: Galea, M.;Gerada, C.;Raminosoa, T.;Wheeler, P.; |
| Apparue dans: IEEE Transactions on Industry Applications |
| Date publication: 02.-2012, volume: 48, issue:1, pages: 79 - 87 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Thermodynamic Analysis of Multistage Adiabatic CAES |
Résumé:
Adiabatic compressed air energy storage (A-CAES) represents a valuable and environmentally friendly option for massive energy storage. Existing examples of CAES refer to underground storage at medium pressure level. But for widespread utilization, independent from the availability of underground storage volumes, artificial reservoirs would be required. This requires rather high air pressure within the storage, which in turn will demand a carefully optimized recovery of the thermal energy released in the compression phase. Starting from a detailed thermodynamic analysis of the relevant design parameters and their influence on the system efficiency, we propose a comprehensive set of criteria for the design of the system, with particular attention to heat transfer devices. |
| Auteurs: Grazzini, G.;Milazzo, A.; |
| Apparue dans: Proceedings of the IEEE |
| Date publication: 02.-2012, volume: 100, issue:2, pages: 461 - 472 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Thermoelectric Energy Harvester Directly Embedded Into Casted Aluminum |
Résumé:
A thermoelectric generator (TG) directly embedded in aluminum is described. The device has been realized using a new silicon thermocouple process with very high temperature stability. It is integrated by direct embedding in the liquid aluminum during casting. The TG generates up to 500  of external electric power. The new technology also opens the path to a new generation of sensors and microsystems embedded in metals during primary shaping. |
| Auteurs: Ibragimov, A.;Pleteit, H.;Pille, C.;Lang, W.; |
| Apparue dans: IEEE Electron Device Letters |
| Date publication: 02.-2012, volume: 33, issue:2, pages: 233 - 235 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Three-Dimensional Electromagnetic Shell Finite Element for Coupled Vector-Scalar Potential Formulations |
Résumé:
In many eddy current problems solved by FEM, meshing of the skin depth leads to CAD difficulties and large computing. In order to avoid such problems, one currently use surface impedance conditions: boundary conditions in the case of massive conductors or transmission conditions or shell elements in the case of thin conducting layers. In this paper, we propose a new shell finite element with arbitrary thickness that is compatible with the $) and $) formulations. Both formulations exist in some general purpose finite element electromagnetic codes like Code_Carmel3D. To validate the approach, two elementary numerical tests are treated. |
| Auteurs: Thomas, P.;Le Menach, Y.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 823 - 826 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Time-Coordination Approach for Regenerative Energy Saving in Multiaxis Motor-Drive Systems |
Résumé:
An analytical approach for the management of regenerative energies in multiaxis servo-motor-drives, which can operate in parallel packaging/assembly/manufacturing lines, is presented in this paper. This energy management is achieved through a proper time-coordination between the speed commands of multiaxis drives. Moreover, the proposed approach significantly limits the peak value of the ac input current in these systems. It is mathematically proved that a time-delay can significantly increase the amount of utilized regenerative energy, and consequently decreases the amount of dissipated energy. In this paper, a set of closed-form formulas is developed for different acceleration-deceleration time ratios, where motor losses are neglected. The findings of this investigation were experimentally verified using a two-axis permanent-magnet motor-drive system, and the results are presented in this paper. The experimental results are in remarkable agreement with the developed closed-form formulas. |
| Auteurs: Kaviani, A.K.;Hadley, B.;Mirafzal, B.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 931 - 941 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Time-Efficient Method for the Simulation of Ion Flow Field of the AC-DC Hybrid Transmission Lines |
Résumé:
The ac-dc hybrid transmission line is an effective way to enhance the transmission capacity of a power corridor. However, the corona discharge of ac and the dc transmission lines may interact with each other, which makes the electric field at the ground level difficult to be predicted. This paper presents a simulation method for the calculation of the field effects caused by the corona activities of hybrid ac-dc transmission lines. This approach can simulate the convection and recombination of the space charge generated by ac or dc corona without improper simplifications, and the conductor surface gradient strictly kept to the onset value. The calculated electric field and ion current density at the ground level agree well with the measurement results of a hybrid line model. |
| Auteurs: Zhou, X.;Cui, X.;Lu, T.;Zhen, Y.;Luo, Z.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 731 - 734 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Translational Coupled Electromagnetic and Thermal Innovative Model for Induction Welding of Tubes |
Résumé:
In the paper, a novel approach to numerical modeling of tube induction welding is proposed. The coupled electromagnetic and thermal model must take into account also the movement of the metal strip: in order to make possible this kind of simulation in reasonable computation time, a simplified approach to the modeling is presented and discussed. |
| Auteurs: Dughiero, F.;Forzan, M.;Pozza, C.;Sieni, E.; |
| Apparue dans: IEEE Transactions on Magnetics |
| Date publication: 02.-2012, volume: 48, issue:2, pages: 483 - 486 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Translinear, Log-Domain FPAA on Standard CMOS Technology |
Résumé:
A field-programmable analog array (FPAA) using a standard-CMOS wide-dynamic-range translinear element (TE) is introduced. The FPAA configurable analog blocks (CABs) are based on a reconfigurable translinear cell (RTC), capable of implementing the basic circuit elements required by translinear and log-domain circuit design. The interfacing is provided by an I/O programmable cell, which allows for easier connectivity between the signal-processing core and the external circuitry. As a proof-of-concept, a 5  5 RTC FPAA testchip was implemented in 0.35- CMOS technology. A set of various circuit primitives, such as one- and four-quadrant multipliers, an Euclidean distance operator and a fourth-order log-domain filter, were mapped on the chip in order to demonstrate the versatility of the approach. FPAA bandwidth reaches 20 MHz with a power consumption of 30  and precision errors below 3%. |
| Auteurs: Fernandez, D.;Martinez-Alvarado, L.;Madrenas, J.; |
| Apparue dans: IEEE Journal of Solid-State Circuits |
| Date publication: 02.-2012, volume: 47, issue:2, pages: 490 - 503 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Two-Dimensional Low-Diameter Scalable On-Chip Network for Interconnecting Thousands of Cores |
Résumé:
This paper introduces the Spidergon-Donut (SD) on-chip interconnection network for interconnecting 1,000 cores in future MPSoCs and CMPs. Unlike the Spidergon network, the SD network which extends the Spidergon network into the second dimension, significantly reduces the network diameter, well below the popular 2D Mesh and Torus networks for one extra node degree and roughly 25 percent more links. A detailed construction of the SD network and a method to reshuffle the SD network's nodes for layout onto the 2D plane, and simple one-to-one and broadcast routing algorithms for the SD network are presented. The various configurations of the SD network are analyzed and compared including detailed area and delay studies. To interconnect a thousand cores, the paper concludes that a hybrid version of the SD network with smaller SD instances interconnected by a crossbar is a feasible low-diameter network topology for interconnecting the cores of a thousand core system. |
| Auteurs: Sibai, F.N.; |
| Apparue dans: IEEE Transactions on Parallel and Distributed Systems |
| Date publication: 02.-2012, volume: 23, issue:2, pages: 193 - 201 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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|
| » A Unified Approach to Reliability Assessment of Multiphase DC–DC Converters in Photovoltaic Energy Conversion Systems |
Résumé:
A systematic framework for reliability assessment and fault-tolerant design of multiphase dc-dc converters deployed in photovoltaic applications is presented. System-level steady-state models allow a detailed specification of component failure rates, and in turn establish the effects of ambient conditions and converter design on reliability. Markov reliability models are derived to estimate the mean time to system failure. Case studies applied to two- and three-phase, 250-W converters demonstrate that topological redundancy does not necessarily translate to improved reliability for all choices of switching frequency and capacitance. Capacitor voltage rating is found to be the dominant factor that affects system reliability. |
| Auteurs: Dhople, S.V.;Davoudi, A.;Domínguez-García, A.D.;Chapman, P.L.; |
| Apparue dans: IEEE Transactions on Power Electronics |
| Date publication: 02.-2012, volume: 27, issue:2, pages: 739 - 751 |
| Editeur: IEEE |
| Document complet vers site de l'éditeur |
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