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Publications dans les journaux scientifiques dans le domaine de l'ingénierie : 02-2010 trié par par titre, page: 6
» Final TerraSAR-X Calibration Results Based on Novel Efficient Methods
Résumé:
TerraSAR-X is a satellite mission for scientific and commercial applications operating a highly flexible X-band synthetic aperture radar (SAR) instrument with a multitude of different operation modes. As product quality is of crucial importance, the success or failure of the mission depends essentially on the method of calibrating TerraSAR-X in an efficient way during commissioning the entire system in a restricted time. Only then, product quality and the correct in-orbit operation of the entire SAR system can be ensured. This paper describes the in-orbit calibration method for TerraSAR-X and dedicated activities performed during the commissioning phase as well as final results derived from all calibration procedures.
Auteurs: Schwerdt, M.;Brautigam, B.;Bachmann, M.;Doring, B.;Schrank, D.;Hueso Gonzalez, J.;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2010, volume: 48, issue:2, pages: 677 - 689
Editeur: IEEE
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» Fine patterning of glycerol-doped PEDOT:PSS on hydrophobic PVP dielectric with ink jet for source and drain electrode of OTFTs
Résumé:
This report describes the fabrication and the electrical characteristics of pentacene OTFTs that use the conducting PEDOT:PSS for the source and drain (S/D) electrodes. By adding a controlled amount (10~20 wt%) of glycerol the conductivity of the PEDOT:PSS ink enhanced to 450 S/cm, and the viscosity of the ink was reduced to less than 20 cps in order for it to be suitable for ink jet printing. In order to create a patterned PEDOT:PSS layer for the S/D electrode on a hydrophobic polyvinylephenol (PVP) gate dielectric, oxygen plasma was applied to control the surface energy of S/D electrode area on...
Auteurs: Myung-Won, Lee , Mi-Young, Lee , Jae-Cheol, Choi , Jong-Seung, Park , Chung-Kun, Song
Apparue dans: Organic Electronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Fingerprint Matching
Résumé:
Fingerprint matching has been successfully used by law enforcement for more than a century. The technology is now finding many other applications such as identity management and access control. The authors describe an automated fingerprint recognition system and identify key challenges and research opportunities in the field.
Auteurs: Jain, Anil K.;Feng, Jianjiang;Nandakumar, Karthik;
Apparue dans: Computer
Date publication: 02.-2010, volume: 43, issue:2, pages: 36 - 44
Editeur: IEEE
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» First Analysis of TerraSAR-X Along-Track InSAR-Derived Current Fields
Résumé:
We present the first analysis of surface current fields derived from TerraSAR-X along-track interferometric synthetic aperture radar (along-track InSAR, ATI) data. The images were acquired over the mouth of the Elbe river (Germany) during six satellite overpasses in spring and summer 2008, using the experimental “aperture switching” mode of TerraSAR-X. In this mode, the phased-array synthetic aperture radar (SAR) antenna is split into two halves for receiving, but in contrast to the “dual receive antenna” mode, which uses two independent receivers in parallel, a single receiver is multiplexed to process signals from the two antenna halves in an alternating manner at a doubled pulse repetition frequency. The effective ATI baseline is on the order of 0.8 m. The SAR/ATI raw data processing is described in another paper in this issue. This paper focuses on the conversion of the basic interferograms into line-of-sight surface current fields, which includes an elimination of ship signatures, identification, and correction (as far as possible) of imaging artifacts, additional filtering and smoothing, and a subtraction of contributions of wave motions to detected velocities according to a theoretical model. We evaluate the quality of the results by comparison with current fields from a numerical flow model and with available in situ data. The ATI performance of TerraSAR-X is found to be basically consistent with theoretical expectations. After applying the same data processing algorithms to all six images, mean differences between TerraSAR-X-derived currents and reference currents in our main test area range from 0.11 to 0.08 m/s in five of the six cases with one outlier at 0.42 m/s. The- spatial current variations within the TerraSAR-X-derived current fields are consistent with the model in three cases, but unrealistically strong variations across the images are found in the other three cases. We attribute this to shortcomings of our preliminary raw data processing algorithms, which can probably be fixed after some more detailed analysis and testing. The results obtained so far encourage us to believe that our internal performance goal of a typical current measuring accuracy of 0.1 m/s at an effective spatial resolution better than 1 km can be met.
Auteurs: Romeiser, R.;Suchandt, S.;Runge, H.;Steinbrecher, U.;Grunler, S.;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2010, volume: 48, issue:2, pages: 820 - 829
Editeur: IEEE
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» First Commercial Deployment of a Colorless Gigabit WDM/TDM Hybrid PON System Using Remote Protocol Terminator
Résumé:
Colorless gigabit wavelength-division-multiplexing (WDM)/time-division-multiplexing (TDM) hybrid passive optical network (PON) using a remote protocol terminator is proposed and experimentally demonstrated. The system consists of reflective semiconductor optical amplifier-based WDM-PON and a legacy TDM-PON, combined with a simple and efficient remote node structure in order to provide high-speed fiber-to-the-home service to a large area with a high population density. The demonstrated system can support 512 subscribers with a single feeder fiber. The performance and feasibility of the system were evaluated by transmitting gigabit per second data including the effects of Rayleigh backscattering and 20 km attenuation. The system has been used by Korea Telecom to provide commercial services in Gwangju, Korea, since March 2009, after successfully passing through the benchmark test. This is the first commercial deployment of a WDM/TDM hybrid PON. It can accommodate field-deployed TDM-PON link without any modification and extend the maximum total reach of PON link by the use of remote protocol termination. Number of subscribers and the allocated bandwidth to the subscribers can be designed by simply changing the splitting ratio.
Auteurs: Lee, J. H.;Cho, S.-H.;Lee, H.-H.;Jung, E.-S.;Yu, J.-H.;Kim, B.-W.;Lee, S.-H.;Koh, J.-S.;Sung, B.-H.;Kang, S.-J.;Kim, J.-H.;Jeong, K.-T.;Lee, S. S.;
Apparue dans: Journal of Lightwave Technology
Date publication: 02.-2010, volume: 28, issue:4, pages: 344 - 351
Editeur: IEEE
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» First operation of the charge-breeder electron-cyclotron-resonance ion source at the Texas A&M Cyclotron Institute
Résumé:
The 14.5 GHz electron-cyclotron-resonance ion source (ECRIS) designed and fabricated specifically for charge breeding has been installed at the Texas A&M University Cyclotron Institute for use in the institute's ongoing radioactive-ion-beam upgrade. The initial testing of the source has just begun with magnetic analysis of the ECRIS beam. The source has only been conditioning for a brief time at low microwave power, and it is continuing to improve. After the source has been conditioned and characterized, charge-breeding trials with stable beams from a singly ionizing source will begin.
Auteurs: May, D. P.;Tabacaru, G.;Abegglen, F. P.;Cornelius, W. D.;
Apparue dans: Review of Scientific Instruments
Date publication: 02.-2010, volume: 81, issue:2, pages: 02A901 - 02A901-2
Editeur: IEEE
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» First-Principles Simulation on Piezoresistive Properties in Doped Silicon Nanosheets
Résumé:
We have simulated the electronic states and piezoresistance coefficients in single-crystal silicon (Si) nanosheets on the basis of first-principles calculations of model structures. The carrier conductivities of the hydrogen-terminated Si nanosheet models with (001) surface orientation have been calculated using band carrier densities and their corresponding effective mass tensors derived from the two-dimensional (2D) band diagram by our original approach for a small amount of carrier occupation. The [110] uniaxial tensile stress causes band deformation, leading to the redistribution of carriers, and a drastic change of conductivity can be observed for nanosheet models. The p-type longitudinal and transverse piezoresistance coefficients about the [110] tensile stress swell up as the nanosheet becomes thinner, and we have obtained high piezoresistance coefficients of 343 × 10-11 Pa-1 of [pi]l[110] and - 141 × 10-11 Pa-1 of [pi]t [110] for about 1 nm thickness. It is expected that p-type ultra-thin Si(001) nanosheet will be a suitable candidate for nanoscale piezoresistors due to its giant piezoresistivity. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Auteurs: Koichi Nakamura, Toshiyuki Toriyama, Susumu Sugiyama
Apparue dans: IEEJ Transactions on Electrical and Electronic Engineering
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Fisher Information-Based Evaluation of Image Quality for Time-of-Flight PET
Résumé:
The use of time-of-flight (TOF) information during positron emission tomography (PET) reconstruction has been found to improve the image quality. In this work we quantified this improvement using two existing methods: 1) a very simple analytical expression only valid for a central point in a large uniform disk source and 2) efficient analytical approximations for postfiltered maximum likelihood expectation maximization (MLEM) reconstruction with a fixed target resolution, predicting the image quality in a pixel or in a small region of interest based on the Fisher information matrix. Using this latter method the weighting function for filtered backprojection reconstruction of TOF PET data proposed by C. Watson can be derived. The image quality was investigated at different locations in various software phantoms. Simplified as well as realistic phantoms, measured both with TOF PET systems and with a conventional PET system, were simulated. Since the time resolution of the system is not always accurately known, the effect on the image quality of using an inaccurate kernel during reconstruction was also examined with the Fisher information-based method. First, we confirmed with this method that the variance improvement in the center of a large uniform disk source is proportional to the disk diameter and inversely proportional to the time resolution. Next, image quality improvement was observed in all pixels, but in eccentric and high-count regions the contrast-to-noise ratio (CNR) increased less than in central and low- or medium-count regions. Finally, the CNR was seen to decrease when the time resolution was inaccurately modeled (too narrow or too wide) during reconstruction. Although the maximum CNR is not very sensitive to the time resolution error, using an inaccurate TOF kernel tends to introduce artifacts in the reconstructed image.
Auteurs: Vunckx, K.;Zhou, L.;Matej, S.;Defrise, M.;Nuyts, J.;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2010, volume: 29, issue:2, pages: 311 - 321
Editeur: IEEE
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» Flat Dry Elastomer Adhesives as Attachment Materials for Climbing Robots
Résumé:
In this paper, flat elastomers are proposed as an attachment material for climbing robots on less than a few micrometer-scale rough surfaces due to their energy-efficient, quiet, and residue-free characteristics. The proper elastomer is chosen by the use of the current adhesion, friction, and peeling elastomer-contact-mechanics models. Then, adhesion and friction properties of the chosen dry flat-elastomer thick films (Vytaflex-10) are characterized on acrylic and smooth and rough glass surfaces for variations in preloads, speeds, contact times, and elastomer thicknesses. A climbing robot with four-bar-based legged-body kinematics is designed and fabricated as simple and lightweight as possible to demonstrate the feasibility of the elastomers as attachment materials on relatively smooth surfaces. The robot utilizes a passive alignment system to make the footpads parallel to the surface on light contact, a peeling mechanism to minimize the detachment vibration, and a passive tail to minimize the pitch-back moment. Experimental results showed that the robot can climb stably on vertical, smooth surfaces in any direction and can walk inverted for a limited amount of time.
Auteurs: Unver, O.;Sitti, M.;
Apparue dans: IEEE Transactions on Robotics
Date publication: 02.-2010, volume: 26, issue:1, pages: 131 - 141
Editeur: IEEE
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» Flexible Circuits and Architectures for Ultralow Power
Résumé:
Subthreshold digital circuits minimize energy per operation and are thus ideal for ultralow-power (ULP) applications with low performance requirements. However, a large range of ULP applications continue to face performance constraints at certain times that exceed the capabilities of subthreshold operation. In this paper, we give two different examples to show that designing flexibility into ULP systems across the architecture and circuit levels can meet both the ULP requirements and the performance demands. Specifically, we first present a method that expands on ultradynamic voltage scaling (UDVS) to combine multiple supply voltages with component level power switches to provide more efficient operation at any energy-delay point and low overhead switching between points. This system supports operation across the space from maximum performance, when necessary, to minimum energy, when possible. It thus combines the benefits of single- , multi- , and dynamic voltage scaling (DVS) while improving on them all. Second, we propose that reconfigurable subthreshold circuits can increase applicability for ULP embedded systems. Since ULP devices conventionally require custom circuit design but the manufacturing volume for many ULP applications is low, a subthreshold field programmable gate array (FPGA) offers a cost-effective custom solution with hardware flexibility that makes it applicable across a wide range of applications. We describe the design of a subthreshold FPGA to support ULP operation and identify key challenges to this effort.
Auteurs: Calhoun, B. H.;Ryan, J. F.;Khanna, S.;Putic, M.;Lach, J.;
Apparue dans: Proceedings of the IEEE
Date publication: 02.-2010, volume: 98, issue:2, pages: 267 - 282
Editeur: IEEE
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» Flexible On-Board Stream Processing for Automotive Sensor Data
Résumé:
Vehicle testing and diagnosis requires huge amounts of data to be gathered and analyzed. Not all possibly interesting data can be stored because of the limited memory available in a tested vehicle. On-board preprocessing of data and decisions about which information has to be kept or omitted is thus vital for vehicle testing routines. This paper introduces a method for flexible on-board processing of sensor data of a vehicle. The approach is motivated by sensor network ideas and makes use of stream processing techniques. A processing graph model for automotive applications is proposed, which consists of operator nodes and connecting data streams. This model supplies both recording and processing functionality together. To account for dynamic changes of conditions within a vehicle—most of the time only a small portion of the vehicle states are interesting for diagnosis—both the model and actual software are built in such a way that the whole system can automatically be adapted at runtime whenever certain conditions are detected. The proposed stream processing model has been implemented in a proof-of-concept industrial application, that was deployed to an automotive on-board unit. Results show that this approach effectively trades a little more on-board processing power for a large data volume, that does not need to be saved and transmitted for off-board usage anymore.
Auteurs: Schweppe, H.;Zimmermann, A.;Grill, D.;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2010, volume: 6, issue:1, pages: 81 - 92
Editeur: IEEE
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» Flexible Silk-Inorganic Nanocomposites: From Transparent to Highly Reflective
Résumé:
A novel type of all-natural, biocompatible, and very robust nanoscale free-standing biohybrids are reported. They are obtained by integrating a silk fibroin matrix with functional inorganic nanoplatelets using a spin-assisted layer-by-layer assembly. The organized assembly of the silk fibroin with clay (montmorillonite) nanosheets results in highly transparent nanoscale films with significantly enhanced mechanical properties, including strength, toughness, and elastic modulus, as compared to those for the pristine silk nanomaterials. Moreover, replacing clay nanoplatelets with a highly reflective Langmuir monolayer of densely packed silver nanoplates causes a similar enhancement of the mechanical properties, but in contrast to the materials above, highly reflective, mirror-like, nanoscale flexible films are created. This strategy offers a new perspective for the fabrication of robust all-natural flexible nanocomposites with exceptional mechanical properties important for biomedical applications, such as reinforced tissue engineering. On the other hand, the ability to convert silk-based nanoscale films into mirror-like biocompatible flexible films can be intriguing for prospective photonics and optical exploitation of these nanobiohybrids.
Auteurs: Eugenia Kharlampieva, Veronika Kozlovskaya, Ray Gunawidjaja, Valeriy V. Shevchenko, Richard Vaia, Rajesh R. Naik, David L. Kaplan, Vladimir V. Tsukruk
Apparue dans: Advanced Functional Materials
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Flipping the CMOS Switch
Résumé:
Wireless communication has become increasingly popular due to its accessibility by anyone at anytime, anywhere. To a great extent, the success of wireless communications has been achieved through the rapid progress in semiconductor technologies, particularly in complementary metal oxide semiconductor (CMOS) technology. Indeed, CMOS has made it possible to integrate radio-frequency (RF), intermediatefrequency (IF) and baseband blocks on the same die at low cost for wireless communication applications. Consequently, this attracts more subscribers to enjoy affordable wireless communication services.
Auteurs: Li, X. Jun;Zhang, Y. Ping;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2010, volume: 11, issue:1, pages: 86 - 96
Editeur: IEEE
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» FLO Corporation partners with Cogent
Résumé:
FLO Corporation, a US company offering registered traveller services, has announced an agreement with Cogent Systems. Under the terms of the agreement the companies will work together to leverage Cogent's national network of over 1,000 biometric enrolment locations for frequent travellers to enrol in the TSA-sponsored RT program. Additionally, Cogent and FLO are working together with airports to restore RT services and develop next-generation solutions for travellers.
Auteurs: [No author name available]
Apparue dans: Biometric Technology Today
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Flood Detection in Urban Areas Using TerraSAR-X
Résumé:
Flooding is a major hazard in both rural and urban areas worldwide, but it is in urban areas that the impacts are most severe. An investigation of the ability of high-resolution TerraSAR-X synthetic aperture radar (SAR) data to detect flooded regions in urban areas is described. The study uses a TerraSAR-X image of a one-in-150-year flood near Tewkesbury, U.K., in 2007, for which contemporaneous aerial photography exists for validation. The German Aerospace Center (DLR) SAR end-to-end simulator (SETES) was used in conjunction with airborne scanning laser altimetry (LiDAR) data to estimate regions of the image in which water would not be visible due to shadow or layover caused by buildings and taller vegetation. A semiautomatic algorithm for the detection of floodwater in urban areas is described, together with its validation using aerial photographs. Of the urban water pixels that are visible to TerraSAR-X, 76% were correctly detected, with an associated false positive rate of 25%. If all the urban water pixels were considered, including those in shadow and layover regions, these figures fell to 58% and 19%, respectively. The algorithm is aimed at producing urban flood extents with which to calibrate and validate urban flood inundation models, and these findings indicate that TerraSAR-X is capable of providing useful data for this purpose.
Auteurs: Mason, D. C.;Speck, R.;Devereux, B.;Schumann, G. J.-P.;Neal, J. C.;Bates, P. D.;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2010, volume: 48, issue:2, pages: 882 - 894
Editeur: IEEE
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» Flying mathematician
Résumé:
His adventure flights over rough mountains yield stunningly accurate maps. Rick Armstrong is snuggled up with a laptop in the cluttered space that was once the backseat of a six-­ passenger Cessna 206. Twenty-­five hundred meters below, sun-­splashed Portland, Ore., slowly dissolves into the Tolkienesque foothills of Mount Hood. It's some beautiful scenery. But right now, Armstrong's eyes are fixed on his computer, which monitors the images that are streaming in from a camera mounted under the belly of the little plane.
Auteurs: Adee, S.;
Apparue dans: IEEE Spectrum
Date publication: 02.-2010, volume: 47, issue:2, pages: 34 - 35
Editeur: IEEE
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» Focused Issue on RFIC [From the Guest Editor's Desk]
Résumé:
The term radio frequency integrated circuit (RFIC) has been widely used in the past ten years. Another term, microwave/millimeter-wave monolithic integrated circuit (MMIC) was utilized much earlier. In fact, radio frequency includes microwave frequencies and millimeterwave frequencies, and therefore RFIC seems to be more general than MMIC. However, these two terms can be used equivalently these days. From the historical point of view, the earliest MMICs were demonstrated using GaAs material in the 1970s, and the III-V compound semiconductor based (GaAs or InP) MMIC technologies became mature during big programs funded by DARPA in the United States, that is, the MIMIC Program (Phase I to III) and its follow-on the MAFET Program, with the time span from 1987 to 1998. The developed MMICs in the MIMIC and MAFET programs cover the frequency range from microwave frequency to about 200 GHz, mostly for military applications. On the other hand, silicon-based integrated circuits (CMOS and/or SiGe HBT), together with the wireless business boom, started to demonstrate microwave performance in the late 1990s. These silicon circuits were the fi rst to be called RFICs. Since the silicon world is much larger than the world of III-V compound semiconductors, people quickly accepted this term. For instance, the current most important IEEE annual conference on RFIC, the IEEE RFIC Symposium, was named the IEEE Microwave and Millimeterwave Monolithic Circuit Symposium (MMWMCS) be fore 1996.
Auteurs: Wang, H.;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2010, volume: 11, issue:1, pages: 10 - 26
Editeur: IEEE
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» Following virtual trails
Résumé:
We are on our way to a mountain top, negotiating the terrain, finding our way up steep cliffs, forcing through the vegetation, and following the bank of a river to locate a place to ford. Then, suddenly, we find a trail going in the right direction. Now everything becomes easier. The trail offers the best route, avoiding all the difficult spots. Coming to the next river, the trail leads us directly to the best place to cross.
Auteurs: Olsen, A.;Malizia, A.;
Apparue dans: IEEE Potentials
Date publication: 02.-2010, volume: 29, issue:1, pages: 24 - 28
Editeur: IEEE
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» Fore and Aft Channel Reconstruction in the TerraSAR-X Dual Receive Antenna Mode
Résumé:
The TerraSAR-X satellite is a high-resolution synthetic aperture radar (SAR) system launched in June 2007 which provides the option to split the antenna in along-track direction and sample two physical channels separately. Modern SARs are equipped with active phased array antennas and multiple channels. In order to keep costs low, TerraSAR-X uses the redundant receiver unit for the second channel such that fore and aft channel signals are combined by a hybrid coupler to form sum and difference channel data. The dual receive antenna (DRA) mode can either be used to acquire along-track interferometric data or to acquire signals with different polarizations at the same time (Quad-Pol). Fore and aft channel reconstruction is necessary if ground moving target indication (GMTI) algorithms such as the displaced phase center antenna technique or along-track interferometry shall be applied, and in order to separate the horizontally and vertically polarized received signal components. The proposed approach uses internal calibration pulses from different calibration beams in order to estimate and compensate the hardware impact. The theoretical framework together with the results from the experimental data evaluation for the fore and aft channel reconstruction of the TerraSAR-X DRA mode are presented. The impact of the receive hardware transformation matrix estimation accuracy on errors in the reconstructed fore and aft channel image data is studied, and first examples on the GMTI capability of the TerraSAR-X DRA mode are given.
Auteurs: Gabele, M.;Brautigam, B.;Schulze, D.;Steinbrecher, U.;Tous-Ramon, N.;Younis, M.;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2010, volume: 48, issue:2, pages: 795 - 806
Editeur: IEEE
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» Foreword to the Special Issue on TerraSAR-X: Mission, Calibration, and First Results
Résumé:
The 34 papers in this special issue provide an overview of the TerraSAR-X mission, commissioning phase, calibration, data processing, and applications.
Auteurs: Moreira, A.;Bamler, R.;
Apparue dans: IEEE Transactions on Geoscience and Remote Sensing
Date publication: 02.-2010, volume: 48, issue:2, pages: 603 - 604
Editeur: IEEE
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» Four Trends Leading to Java Runtime Bloat
Résumé:
The drive to rapidly develop layered, interconnected, and flexible systems has eclipsed consideration of resource costs. Consequently, large Java applications suffer from runtime bloat: a large and pervasive infrastructure tax, where simple transactions require a few hundred thousand method calls, and a server with 1 Gbyte of memory sometimes can only support a few hundred users. Current Java optimizers and garbage collectors are of little help for these systemic problems. Enterprises face greatly reduced scalability, increased power consumption, and missed deliveries. In this article, the authors detail four global software development trends, along with some widely held myths, that lead to bloat in Java applications. They illustrate their consequences with anecdotes drawn from real applications suffering severe performance and memory issues. While these trends are inevitable, runtime bloat is not. Understanding the sources of bloat can help programmers craft appropriate solutions for the future.
Auteurs: Mitchell, Nick;Schonberg, Edith;Sevitsky, Gary;
Apparue dans: IEEE Software
Date publication: 02.-2010, volume: 27, issue:1, pages: 56 - 63
Editeur: IEEE
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» Fractional Differential Mask: A Fractional Differential-Based Approach for Multiscale Texture Enhancement
Résumé:
In this paper, we intend to implement a class of fractional differential masks with high-precision. Thanks to two commonly used definitions of fractional differential for what are known as GrÜmwald–Letnikov and Riemann–Liouville, we propose six fractional differential masks and present the structures and parameters of each mask respectively on the direction of negative x-coordinate, positive x-coordinate, negative y-coordinate, positive y-coordinate, left downward diagonal, left upward diagonal, right downward diagonal, and right upward diagonal. Moreover, by theoretical and experimental analyzing, we demonstrate the second is the best performance fractional differential mask of the proposed six ones. Finally, we discuss further the capability of multiscale fractional differential masks for texture enhancement. Experiments show that, for rich-grained digital image, the capability of nonlinearly enhancing complex texture details in smooth area by fractional differential-based approach appears obvious better than by traditional intergral-based algorithms.
Auteurs: Pu, Y.-F.;Zhou, J.-L.;Yuan, X.;
Apparue dans: IEEE Transactions on Image Processing
Date publication: 02.-2010, volume: 19, issue:2, pages: 491 - 511
Editeur: IEEE
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» Fractional modelling and identification of thermal systems
Résumé:
Heat transfer in homogeneous media obeys to diffusion phenomenon which can be modeled with the help of fractional systems. In this paper, we use a parsimonious black box model based on an original fractional integrator whose order1/2 acts only over a limited spectral band. We carried out simulations of front face thermal experimentations which consist in measuring the temperature at the surface of a material where a random heat flux is applied. We consider the characterization of the thermal behaviour of a wall or a sphere. These simulations show the ability of the fractional model, thanks to an output error...
Auteurs: J.D., Gabano , T., Poinot
Apparue dans: Signal Processing
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Frame-Loss-Free Optical Line Switching System for In-Service Optical Network
Résumé:
Fiber-to-the-home (FTTH) has now reached the stage where it is providing real-time broadband services. Since even a temporary suspension of broadcasting and telephone services cannot be permitted, it has become important to improve the reliability of FTTH network operation. We have developed an advanced optical line switching system that diverts transmission signals from an in-service line to a spare line without interrupting communication. This system is realized by equalizing the transmission times of the signals sent through dualized lines composed of an in-service line and a spare line. The transmission times are equalized by employing two techniques in the dualized lines. One is a technique that uses a free space optics system to tune the optical line length continuously. The other is a technique for measuring a wide range of time differences between signals transmitted through the dualized lines. Since the dualized lines have a Mach–Zehnder interference structure, the differences can be detected with high accuracy by employing dual-light interferometry. We applied this switching system to a gigabit Ethernet passive optical network (GE-PON) during transmission and succeeded in switching in-service lines without inducing any frame loss.
Auteurs: Tanaka, K.;Tsujimura, T.;Yoshida, K.;Katayama, K.;Azuma, Y.;Shimizu, M.;
Apparue dans: Journal of Lightwave Technology
Date publication: 02.-2010, volume: 28, issue:4, pages: 539 - 546
Editeur: IEEE
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» Free-Standing Lithium Niobate Microring Resonators for Hybrid Integrated Optics
Résumé:
We report on the fabrication of free-standing microrings using ion-sliced lithium niobate thin films bonded by benzocyclobutene on a lithium niobate substrate. The microrings can be detached from the benzocyclobutene layer using standard clean-1 solution and transferred onto any host substrate. This approach is suitable for building hybrid integrated optics devices with laterally and vertically coupled lithium niobate microring resonators. Gallium nitride was identified as a suitable material for the port waveguides in such a device due to the refractive index similar to lithium niobate. In our study, we transferred lithium niobate microrings on top of gallium nitride waveguides and aligned them for vertical coupling using a micropositioning tool. Transverse-electric-wave transmission spectra of the microring resonators with a radius of 20 m exhibited a free spectral range of 8.1 nm and a finesse of 23 at 1.55- m wavelength. The resonance dips in these spectra showed an extinction ratio of up to 12 dB.
Auteurs: Koechlin, M.;Sulser, F.;Sitar, Z.;Poberaj, G.;Gunter, P.;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2010, volume: 22, issue:4, pages: 251 - 253
Editeur: IEEE
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» Frequency and Polarization Characteristics of Correlated Photon-Pair Generation Using a Silicon Wire Waveguide
Résumé:
We report the frequency and polarization characteristics of correlated photon pairs generated in a Si wire waveguide (SWW). We confirmed that the bandwidth for correlated photon-pair generation was at least >2.8 THz. Moreover, we carried out a classical four-wave mixing experiment using strong pump and idler lights to estimate the bandwidth for correlated photon-pair generation. The results indicated that it is possible to generate photon pairs over a bandwidth as large as 12 THz. We also showed that the generation efficiencies of the signal and idler photons for the horizontal polarization mode were much higher than those for the vertical polarization mode. This is probably caused by the large efficiencies in the group indexes and the effective cross-sectional areas for the two polarization modes. Furthermore, the bandwidth for the correlated photon-pair generation in the vertical polarization mode was 1 THz, and this was much narrower than that for the horizontal polarization mode. The difference between the bandwidths of the two polarization modes indicates that the SWW dispersion for the vertical polarization mode is significantly larger than that for the horizontal polarization mode. We then confirmed that the noise photons generated by spontaneous Raman scattering in an SWW were suppressed to below the detection limit of our setup.
Auteurs: Harada, K.-i.;Takesue, H.;Fukuda, H.;Tsuchizawa, T.;Watanabe, T.;Yamada, K.;Tokura, Y.;Itabashi, S.-i.;
Apparue dans: IEEE Journal of Selected Topics in Quantum Electronics
Date publication: 02.-2010, volume: 16, issue:1, pages: 325 - 331
Editeur: IEEE
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» Frequency and temporal coherence properties of distributed Bragg reflector laser
Résumé:
This article presents the investigation of frequency and temporal coherence properties of distributed Bragg reflector laser. In this scheme, a square-waveform voltage is applied to the phase section of the laser to tune optical wavelength, and delayed optical heterodyne technique is used for the analysis of spectral characteristics. Experiments show that lightwaves emitted from the same active region asynchronously are partially frequency and temporal coherent. When the two wavelengths are closer, the two waves are strongly coherent, and the coherence properties get weak as the delay time increases. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:822-825, 2010; DOI 10.1002/mop.25031
Auteurs: Jian Hong Ke, Ning Hua Zhu, Hong Guang Zhang, Jiang Wei Man, Ling Juan Zhao, Wei Chen, Xin Wang, Yu Liu, Hai Qing Yuan, Liang Xie, Wei Wang
Apparue dans: Microwave and Optical Technology Letters
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Frequency Characteristics of 1-D Periodic Structures with Tapered Microstrip Lines
Résumé:
The electromagnetic bandgap (EBG) structure is a kind of photonic crystal that can be used in microwave and millimeter-wave frequency regions. In this paper, we present the analysis and design of two types of periodic structure circuit with one-dimensional (1-D) EBG structures using alternately arranged, linear, tapered microstrip line (MSL) elements. In order to design the circuits, we calculated their frequency characteristics on the basis of transmission line models. First, we found an ABCD matrix using a model consisting of very short, series-connected MSL elements. Thereafter, we converted these ABCD matrices into S matrices. Based on the theoretical analyses, we fabricated two types of circuits on printed circuit boards (PCBs) and evaluated their frequency characteristics. The results of evaluation showed that one of the circuits had a stopband of 2 GHz bandwidth and the other had a passband in the center of the stopband. The measured and calculated results were found to be in good agreement. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Auteurs: Kenji Matsushita, Makoto Fukuda
Apparue dans: IEEJ Transactions on Electrical and Electronic Engineering
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Frequency Effect on Voltage Linearity of -Based RF Metal–Insulator–Metal Capacitors
Résumé:
This letter deals with the electrical and wideband frequency characterizations of metal–insulator–metal capacitors integrating medium- material, . In particular, this letter focuses on the frequency effect on the voltage linearity of these capacitors and material. The dependence of the voltage–capacitance coefficient (VCC) is, for the first time, studied from 1 kHz to 1 GHz. Intrinsic or extrinsic material origin of the VCC are discussed.
Auteurs: Bertaud, T.;Blonkowski, S.;Bermond, C.;Vallee, C.;Gonon, P.;Gros-Jean, M.;Flechet, B.;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2010, volume: 31, issue:2, pages: 114 - 116
Editeur: IEEE
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» Frequency estimation of real-valued single-tone in colored noise using multiple autocorrelation lags?
Résumé:
The problem of frequency estimation of a real-valued sinusoid in colored noise is addressed. A new estimator using higher-order lags of the sample autocorrelation is proposed, and a statistical analysis is provided. Computer simulations are included to validate the theoretical development and to demonstrate that the proposed approach outperforms several existing frequency estimators in terms of estimation accuracy.
Auteurs: Rim, Elasmi-Ksibi , Hichem, Besbes , Roberto, López-Valcarce , Sofiane, Cherif
Apparue dans: Signal Processing
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Frequency Estimation of Three-Phase Power System Using Weighted-Least-Square Algorithm and Adaptive FIR Filtering
Résumé:
A new technique for estimation of the instantaneous frequency based on simultaneous sampling of three-phase voltage signals is presented. The structure consists of two decoupled modules: the first is for adaptive filtering of input signals, and the second is for frequency estimation. A suitable and robust algorithm for frequency estimation is obtained. This technique provides better performance, compared with the technique based on a single-phase signal in relation to waveforms with noise. The technique is particularly important when asymmetric sags generate zero voltage in one of the three phases. In addition, it allows the measurement of the instantaneous frequency value of real signals for single- or three-phase systems. To demonstrate the performance of the developed algorithm, computer-simulated data records and calibrator-generated signals are processed. The proposed algorithm has been put to test with distorted three-phase voltage signals.
Auteurs: Kusljevic, M. D.;Tomic, J. J.;Jovanovic, L. D.;
Apparue dans: IEEE Transactions on Instrumentation and Measurement
Date publication: 02.-2010, volume: 59, issue:2, pages: 322 - 329
Editeur: IEEE
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» Frequency induced risk assessment for a power system accounting uncertainties in operation of protective equipments
Résumé:
A simple deterministic frequency stability model is developed in this work together with its stochastic counterpart. While the deterministic model captures the fundamental characteristics of short-term frequency dynamics such as abnormal frequency tripping of generators, the stochastic model further maintains the probabilistic characteristics of frequency dynamics, such as stochastic characteristics of frequency relays. The models are particularly suitable for studying system cascading failures introduced by frequency distortions. Our simulation results reveal that the relationship between blackout power loss and frequency has the characteristics of power law.
Auteurs: Y., Yu , D., Gan , H., Wu , Z., Han
Apparue dans: International Journal of Electrical Power & Energy Systems
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Frequency-Shift Acceleration Control for Anti-Islanding of a Distributed-Generation Inverter
Résumé:
This paper proposes frequency-shift acceleration control for anti-islanding of an inverter-based distributed generator. The proposed control is based on frequency positive feedback in the synchronous frame. Overall, the scheme of the proposed control is described. The design methodology of the frequency-shift acceleration gain is presented based on small-signal stability and step input response. The proposed control is intended for zero nondetection zone, noncompromised power quality, and easy implementation without additional devices required. Simulation and experimental results verify that the proposed anti-islanding scheme and the gain design approach are effective and useful in real applications.
Auteurs: Kim, S.-K.;Jeon, J.-H.;Ahn, J.-B.;Lee, B.;Kwon, S.-H.;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 02.-2010, volume: 57, issue:2, pages: 494 - 504
Editeur: IEEE
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» From One Key Member to All Key Members [Microwave Musings]
Résumé:
Auteurs: Remley, K.;Tomiyasu, K.;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2010, volume: 11, issue:1, pages: 152 - 150
Editeur: IEEE
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» From power to applications---A two-year journey
Résumé:
Perhaps few people know the origin of the IEEE Industry Applications Society (IAS) Electric Machines Committee (EMC). EMC is one of the most active committees in the IAS. It sponsored 44 technical papers at the 2008 IAS Annual Meeting, and, as of September 2009, it had received 140 manuscript submissions to the IAS ScholarOne Manuscripts site, making it the most prolific technical committee in IAS. Many of these papers originated at cosponsored technical conferences held by non-IEEE organizations outside North America. Figure 1 depicts the global reach of EMC as measured in the list of countries from which papers have been received for review within the past year. Typically, each year, one or two papers are awarded prizes for their originality, technical content, and expertise.
Auteurs: Johnson, J.H.;
Apparue dans: IEEE Industry Applications Magazine
Date publication: 02.-2010, volume: 16, issue:1, pages: 7 - 9
Editeur: IEEE
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» From the Editor
Résumé:
Auteurs: Farris, George F.;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 02.-2010, volume: 57, issue:1, pages: 2 - 3
Editeur: IEEE
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» From the editors' desk
Résumé:
Auteurs: Cherney, E.;Fleming, R.;Audrieth, L.;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 02.-2010, volume: 26, issue:1, pages: 5 - 6
Editeur: IEEE
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» Fuel cells and HVDC [review of Modeling and Control of Fuel Cells: Distributed Generation Applications (M. H. Nehrir and Caisheng Wang; 2009)] [Book Reviews]
Résumé:
This book is a good introductory text for a course on fuel cells (FCs) in the graduate power engineering curriculum and a handy reference for practicing engineers working in FCs and their integration to power grids as distributed generation (DG) sources.
Auteurs: Lee, K.Y.;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2010, volume: 8, issue:1, pages: 78 - 80
Editeur: IEEE
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» Fuell cells and HVDC [review of HVDC Transmission: Power Conversion Applications in Power Systems by C.-K. Kim et al.; 2009)] [Book Reviews]
Résumé:
This book succeeds in providing a comprehensive textbook on HVDC system design, planning, and application issues. A wide range of subjects including power electronics, power systems, substation design, and control system design are covered. A second edition of the book could benefit from an increased number of references, the quotation of the references in the body text, the provision of time-domain plots for power system integration performance of the HVDC, and the inclusion of a more detailed discussion on power system integration performance of VSC HVDC.
Auteurs: Badrzadeh, B.;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2010, volume: 8, issue:1, pages: 80 - 82
Editeur: IEEE
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» Full band waveguide turnstile junction orthomode transducer with phase matched outputs
Résumé:
A >40% bandwidth fully scalable turnstile-based waveguide orthomode transducer having excellent phase performance is described for the WR75 standard rectangular waveguide. Flexible bandwidth tuning is achieved through the use of an interchangeable stepped scattering element. Reduced height waveguide topology provides a simple, compact, and robust design against mechanical tolerances. The intrinsic broadband nature of half-height E-plane bends and single-step power combiners assures high order mode free increased bandwidth in balanced phase operation. The designed orthomode transducer exhibits a return loss better than 23 dB at any port, an insertion loss less than 0.06 dB, and an isolation of 50 dB over the full bandwidth. Moreover, the phase difference between orthogonal polarizations is lower than 0.7° over the band, thus enabling applications where phase-matched outputs are required. This design has been chosen for the QUIJOTE cosmic microwave background experiment due to its cost-effective, compact design, and high-quality performance as well as being readily scalable to the WR51 and WR28 waveguide bands. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010.
Auteurs: Juan L. Cano, Abdelwahed Tribak, Roger Hoyland, Angel Mediavilla, Eduardo Artal
Apparue dans: International Journal of RF and Microwave Computer-Aided Engineering
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Full horizon optimal FIR estimator of clock state employing measurement of time errors
Résumé:
This paper addresses a p-shift full horizon optimal finite impulse response (FIR) estimator of clock state employing all the measurement data available of the time interval error (TIE). A solution proposed is general for filtering (p=0), prediction (p>0), and smoothing (p<0) of discrete time clock models in state space. The optimal estimator self-determines the clock initial mean square state by solving the discrete algebraic Riccati equation on a measurement interval of N points. Noise is allowed to be zero-mean with arbitrary distribution and covariance functions. The unbiased FIR estimator is proposed in the batch form producing near optimal estimates when...
Auteurs: Yuriy S., Shmaliy
Apparue dans: AEU - International Journal of Electronics and Communications
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Full Sheet Control Using Steerable Nips
Résumé:
This paper describes the mechatronics design, prototype testing, and control of a steerable nips component for paper path mechanisms in high-speed color printers and photocopiers. When placed upstream from the image transfer station along the paper path, this device precisely controls the longitudinal, lateral, and skew directions of papers sheets, as they arrive to the image transfer station. The paper also presents a complete kinematic and dynamic analysis of the paper sheet steering mechanism, which is validated by experimental results. It is shown that the dynamics of a sheet under the control of the steerable nips mechanism are nonlinear and subject to nonholonomic constraints. A feedback linearization control strategy that includes dynamic surface control is developed and implemented to control the sheet's position and angular orientation under the condition that the sheet's speed in the longitudinal direction remains positive at all times. Experimental results verify that the steerable nips mechanism under the proposed feedback linearization control strategy is able to meet or exceed all design performance requirements for deployment as a component of an actual printer paper path control mechanism.
Auteurs: Sanchez, R.;Horowitz, R.;Tomizuka, M.;
Apparue dans: IEEE/ASME Transactions on Mechatronics
Date publication: 02.-2010, volume: 15, issue:1, pages: 48 - 58
Editeur: IEEE
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» Full-order observer design for a class of port-Hamiltonian systems?
Résumé:
We consider a special class of port-Hamiltonian systems for which we propose a design methodology for constructing globally exponentially stable full-order observers using a passivity based approach. The essential idea is to make the augmented system consisting of the plant and the observer dynamics to become strictly passive with respect to an invariant manifold defined on the extended state-space, on which the state estimation error is zero. We first introduce the concept of passivity of a system with respect to a manifold by defining a new input and output on the extended state-space and then perform a partial state feedback...
Auteurs: A., Venkatraman , A.J., van der Schaft
Apparue dans: Automatica
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Full-Wafer Characterization of AlGaN/GaN HEMTs on Free-Standing CVD Diamond Substrates
Résumé:
We report on electrical characterization and uniformity measurements of the first conventionally processed AlGaN/GaN high electron mobility transistors (HEMTs) on free-standing chemical-vapor-deposited (CVD) diamond substrate wafers. DC and RF device performance is reported on HEMTs fabricated on -thick and 30-mm round CVD diamond substrates without mechanical carrying wafers. A measured product of 12.5 is the best reported data for all GaN-on-diamond technology. X-band power performance of AlGaN/GaN HEMTs on diamond is reported to be 2.08 W/mm and 44.1% power added efficiency. This letter demonstrates the potential for GaN HEMTs to be fabricated on CVD diamond substrates utilizing contact lithography process techniques. Further optimization of the epitaxy and diamond substrate attachment process could provide for improvements in thermal spreading while preserving the electrical properties.
Auteurs: Chabak, K. D.;Gillespie, J. K.;Miller, V.;Crespo, A.;Roussos, J.;Trejo, M.;Walker, D. E.;Via, G. D.;Jessen, G. H.;Wasserbauer, J.;Faili, F.;Babic, D. I.;Francis, D.;Ejeckam, F.;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2010, volume: 31, issue:2, pages: 99 - 101
Editeur: IEEE
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» Fully Transparent Non-volatile Memory Thin-Film Transistors Using an Organic Ferroelectric and Oxide Semiconductor Below 200 °C
Résumé:
A fully transparent non-volatile memory thin-film transistor (T-MTFT) is demonstrated. The gate stack is composed of organic ferroelectric poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] and oxide semiconducting Al-Zn-Sn-O (AZTO) layers, in which thin Al2O3 is introduced between two layers. All the fabrication processes are performed below 200 °C on the glass substrate. The transmittance of the fabricated device was more than 90% at the wavelength of 550 nm. The memory window obtained in the T-MTFT was 7.5 V with a gate voltage sweep of -10 to 10 V, and it was still 1.8 V even with a lower voltage sweep of -6 to 6 V. The field-effect mobility, subthreshold swing, on/off ratio, and gate leakage currents were obtained to be 32.2 cm2 V-1 s-1, 0.45 V decade-1, 108, and 10-13 A, respectively. All these characteristics correspond to the best performances among all types of non-volatile memory transistors reported so far, although the programming speed and retention time should be more improved.
Auteurs: Sung-Min Yoon, Shinhyuk Yang, Chunwon Byun, Sang-Hee K. Park, Doo-Hee Cho, Soon-Won Jung, Oh-Sang Kwon, Chi-Sun Hwang
Apparue dans: Advanced Functional Materials
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Functionalized Dithieno[2,3-b:3',2'-d]thiophenes (DTTs) for Organic Thin-Film Transistors
Résumé:
A series of dithieno[2,3-b:3',2'-d]thiophene (DTT; 1) derivatives were synthesized and characterized. Facile, one-pot [2+1] and [1+1+1] synthetic methods of DTT were developed, which enabled the efficient realization of a new DTT-based semiconductor series for organic thin-film transistors (OTFTs). These DTTs are end-functionalized with perfluorophenyl (FP-), perfluorobenzoyl (FB-), benzoyl (B-), 2-naphthylcarbonyl (Np-), 2-benzothiazolyl (BS-), 2-thienylcarbonyl (T-), and 2-(5-hexyl)thienylcarbonyl (HT-) groups. The molecular structures of DFP-DTT (3), DFB-DTT (4), FBB-DTT (5), DB-DTT (6), and DNp-TT (7) were determined via single-crystal X-ray diffraction. Our studies reveal that the majority of these carbonyl-containing derivatives exhibit p-channel transport with hole mobilities of up to 0.01...
Auteurs: Choongik, Kim , Ming-Chou, Chen , Yen-Ju, Chiang , Yue-Jhih, Guo , Jangdae, Youn , ...
Apparue dans: Organic Electronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Funnel Control With Saturation: Linear MIMO Systems
Résumé:
Tracking—by the system output—of a reference signal (assumed bounded with essentially bounded derivative) is considered in the context of linear -input, -output systems subject to input saturation. The system is assumed to have strict relative degree one with stable zero dynamics. Prespecified is a performance funnel, within which the tracking error is required to evolve: transient and asymptotic behavior of the tracking error is influenced through choice of parameter values which define the funnel. The control structure is a saturating error feedback with a gain function designed to evolve so as to preclude contact with the funnel boundary. A feasibility condition (formulated in terms of the system data, the saturation bounds, the funnel data, bounds on the reference signal, and the initial state) is presented under which the tracking objective is achieved, whilst maintaining boundedness of all signals.
Auteurs: Hopfe, N.;Ilchmann, A.;Ryan, E. P.;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2010, volume: 55, issue:2, pages: 532 - 538
Editeur: IEEE
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» Further Improvements in Real-Time Load-Pull Measurement Accuracy
Résumé:
This letter proposes a new solution to improve the accuracy of real-time load-pull measurement systems. Since it is well known that load-pull measurement accuracy depends on the calibration residual uncertainty, the presented solution uses a new algorithm to reduce it. Measurement results that corroborate the proposed solution, with respect to the previous one, show the improvements that have been achieved.
Auteurs: Bonino, S.;Teppati, V.;Ferrero, A.;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 02.-2010, volume: 20, issue:2, pages: 121 - 123
Editeur: IEEE
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» FUZZ-IEEE 2009 Conference Report [Conference Report]
Résumé:
Auteurs: Rhee, F. C.-H.;
Apparue dans: IEEE Computational Intelligence Magazine
Date publication: 02.-2010, volume: 5, issue:1, pages: 8 - 9
Editeur: IEEE
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» Fuzzy Arithmetic for the DC Load Flow
Résumé:
The consideration of uncertainties in the future system operation is a key aspect in current planning methodologies. In this context, load flow studies based on probabilistic theory, fuzzy numbers, and Monte Carlo simulations have been proposed in the literature. This work analyzes in a novel way the application of fuzzy number arithmetic for the DC load flow problem. In this sense, fuzzy sets theory is reviewed and is showed that there are two alternative and valid procedures to perform a subtraction. A key aspect for the right selection of one of these procedures is the independency or dependency among the involved variables. Assuming input data as independent variables, this work is focused on analyzing the fuzzy subtraction between dependent state variables of the system, such as voltage phase angle. Accordingly, two new valid alternative methodologies are proposed and applied to case studies. Results are compared to previous related works showing the consistency of the proposed methodologies. Future research will be focused on the consideration of ohmic losses and AC network modeling in the field of expansion planning studies.
Auteurs: Cortes-Carmona, M.;Palma-Behnke, R.;Jimenez-Estevez, G.;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 02.-2010, volume: 25, issue:1, pages: 206 - 214
Editeur: IEEE
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» Fuzzy Filtering for Physiological Signal Analysis
Résumé:
This study suggests the use of fuzzy-filtering algorithms to deal with the uncertainties associated to the analysis of physiological signals. The signal characteristics, for a given situation or physiological state, vary for an individual over time and also vary among the individuals with the same state. These random variations are due to the several factors related to the physiological behavior of individuals, which cannot be taken into account in the interpretation of signal characteristics. Our approach is to reduce the effect of random variations on the analysis of signal characteristics via filtering out randomness or uncertainty from the signal using a nonlinear fuzzy filter. A fuzzy-filtering algorithm, which is based on a modification of filtering algorithm of Kumar et al. [M. Kumar, N. Stoll, and R. Stoll, IEEE Trans. Fuzzy Syst., vol. 17, no. 1, pp. 150–166, Feb. 2009], is proposed for an improved performance. The method is illustrated by studying the effect of head-up tilting on the heart-rate signal of 40 healthy subjects.
Auteurs: Kumar, M.;Weippert, M.;Arndt, D.;Kreuzfeld, S.;Thurow, K.;Stoll, N.;Stoll, R.;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2010, volume: 18, issue:1, pages: 208 - 216
Editeur: IEEE
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» Fuzzy PCA-Guided Robust -Means Clustering
Résumé:
This paper proposes a new approach to robust clustering, in which a robust -means partition is derived by using a noise-rejection mechanism based on the noise-clustering approach. The responsibility weight of each sample for the -means process is estimated by considering the noise degree of the sample, and cluster indicators are calculated in a fuzzy principal-component-analysis (PCA) guided manner, where fuzzy PCA-guided robust -means is performed by considering responsibility weights of samples. Then, the proposed method achieves cluster-core estimation in a deterministic way. The validity of the derived cluster cores is visually assessed through distance-sensitive ordering, which considers responsibility weights of samples. Numerical experiments demonstrate that the proposed method is useful for capturing cluster cores by rejecting noise samples, and we can easily assess cluster validity by using cluster-crossing curves.
Auteurs: Honda, K.;Notsu, A.;Ichihashi, H.;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2010, volume: 18, issue:1, pages: 67 - 79
Editeur: IEEE
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» Gas sensing with self-assembled monolayer field-effect transistors
Résumé:
A new sensitive gas sensor based on a self-assembled monolayer field-effect transistor (SAMFET) was used to detect the biomarker nitric oxide. A SAMFET based sensor is highly sensitive because the analyte and the active channel are separated by only one monolayer. SAMFETs were functionalized for direct NO detection using iron porphyrin as a specific receptor. A threshold voltage shift towards positive gate biases with increasing NO content was observed. The sensor response was examined as a function of NO concentration. High sensitivity has been demonstrated by detection of ppb concentrations of NO. Preliminary measurements have been performed to determine the...
Auteurs: Anne-Marije, Andringa , Mark-Jan, Spijkman , Edsger C.P., Smits , Simon G.J., Mathijssen , Paul A. van, Hal , ...
Apparue dans: Organic Electronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Gate leakage lowering and kink current suppression for antimonide-based field-effect transistors
Résumé:
Conventional InAs/AlSb HEMTs suffer from chemical instability in materials and high kink current. To avoid these drawbacks, this work proposes a novel layer structure of an InAsSb/AlSb HEMT and a novel two-step passivation process. Performance improvements are reduced dc output conductance by approximately 4.6 times at VDS=0.5V and ID=100mA/mm, and gate leakage to 1×10-3mA/mm from 4 at VGS=-1.2V and VDS=0.8V compared with those of two InAs/AlSb HEMTs, one with the conventional one-step and the other with the proposed two-step passivation process. Both dc and rf performances show strong evidences of impact ionization suppression.
Auteurs: H.-K., Lin , Y.-C., Lin , F.-H., Huang , T.-W., Fan , P.-C., Chiu , ...
Apparue dans: Solid-State Electronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Gate tunneling leakage current behavior of 40nm PD SOI NMOS device considering the floating body effect
Résumé:
This paper reports an analysis of floating body effect related gate tunneling leakage current behavior of the 40nm PD SOI NMOS device using bipolar/MOS equivalent circuit approach. As confirmed by the experimentally measured data, the bipolar/MOS equivalent circuit approach could predict the gate tunneling leakage current behavior, which is strongly affected by the parasitic bipolar device in the floating body as observed from the perpendicular electric field along the path of the U-shaped edges of the polysilicon gate.
Auteurs: H.J., Hung , J.B., Kuo , D., Chen , C.S., Yeh
Apparue dans: Microelectronics Reliability
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» General Bond Graph model for piezoelectric actuators and methodology for experimental identification
Résumé:
Piezoelectric actuators are becoming very popular in applications such as nanopositioning, active vibration control or noise reduction, sometimes as part of so called smart structures. The possibility of accurately moving big loads on a micrometric scale and over a wide range of frequencies has resulted in an intense growth of this technology. This interest has prompted the development of a wide variety of mathematical models available for describing their behaviour, whose suitability depends on the specific application involved. This work overcomes this limitation by unifying the different modelization options for stack and stack-based actuators in a general Bond Graph model...
Auteurs: J.M., Rodriguez-Fortun , J., Orus , F., Buil , J.A., Castellanos
Apparue dans: Mechatronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» General design of the International Fusion Materials Irradiation Facility deuteron injector: Source and beam line
Résumé:
In the framework of the International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities (IFMIF-EVEDA) project, CEA/IRFU is in charge of the design and realization of the 140 mA cw deuteron Injector. The electron cyclotron resonance ion source operates at 2.45 GHz and a 4 electrode extraction system has been chosen. A 2 solenoid beam line, together with a high space charge compensation have been optimized for a proper beam injection in the 175 MHz radio frequency quadrupole. The injector will be tested with proton and deuteron beam production either in pulsed mode or in cw mode on the CEA-Saclay site before to be shipped to Japan. Special attention was paid to neutron emission due to (d,D) reaction. In this paper, the general IFMIF Injector design is reported, pointing out beam dynamics, radioprotection, diagnostics, and mechanical aspects.
Auteurs: Gobin, R.;Blideanu, V.;Bogard, D.;Bourdelle, G.;Chauvin, N.;Delferriere, O.;Girardot, P.;Jannin, J. L.;Langlois, S.;Loiseau, D.;Pottin, B.;Rousse, J.-Y.;Senee, F.;
Apparue dans: Review of Scientific Instruments
Date publication: 02.-2010, volume: 81, issue:2, pages: 02B301 - 02B301-3
Editeur: IEEE
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» Generalization of order distribution concept use in the fractional order system identification
Résumé:
In this paper, the order distribution concept in the frequency domain identification has been extended to include fractional order systems having poles and zeros simultaneously. The existing nonlinear optimization problem appeared when both poles and zeros exist is changed to a quadratic problem that can be solved using least squares algorithms. To collect the required data, system is excited by a multi sine input signal with appropriately selected frequencies. Then a nonparametric identification in frequency domain is accomplished to calculate the Empirical Transfer Function Estimate (ETFE). This estimate is then used to implement the frequency domain identification on all defined...
Auteurs: Peyman, Nazarian , Mohammad, Haeri
Apparue dans: Signal Processing
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Generalized MIMO transmit preprocessing using pilot symbol assisted rateless codes
Résumé:
In this paper, we propose a generalized multipleinput multiple-output (MIMO) transmit preprocessing system, where both the channel coding and the linear MIMO transmit precoding components exploit the knowledge of the channel. This was achieved by exploiting the inherently flexible nature of a specific family of rateless codes that are capable of modifying their code-rate as well as their degree distribution based on the channel state information (CSI), in an attempt to adapt to the time-varying nature of the channel. Moreover, we also propose a novel technique, hereby referred to as pilot symbol assisted rateless (PSAR) coding, where a predetermined fraction of binary pilot symbols is interspersed with the channel-coded bits at the channel coding stage, instead of multiplexing the pilots with the data symbols at the modulation stage, as in classic pilot symbol assisted modulation (PSAM). We will subsequently demonstrate that the PSAR code-aided transmit preprocessing scheme succeeds in gleaning more beneficial knowledge from the inserted pilots, because the pilot bits are not only useful for estimating the channel at the receiver, but they are also beneficial in terms of significantly reducing the computational complexity of the rateless channel decoder. Our results suggest that more than a 30% reduction in the decoder¿s computational complexity can be attained by the proposed system, when compared to a corresponding benchmarker scheme having the same pilot overhead but using the PSAM technique.
Auteurs: Bonello, N.;Yang, D.;Chen, S.;Hanzo, L.;
Apparue dans: IEEE Transactions on Wireless Communications
Date publication: 02.-2010, volume: 9, issue:2, pages: 754 - 763
Editeur: IEEE
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» Generalized Triangular Decomposition in Transform Coding
Résumé:
A general family of optimal transform coders (TCs) is introduced here based on the generalized triangular decomposition (GTD) developed by Jiang This family includes the Karhunen–Loeve transform (KLT) and the generalized version of the prediction-based lower triangular transform (PLT) introduced by Phoong and Lin as special cases. The coding gain of the entire family, with optimal bit allocation, is equal to that of the KLT and the PLT. Even though the original PLT introduced by Phoong is not applicable for vectors that are not blocked versions of scalar wide sense stationary processes, the GTD-based family includes members that are natural extensions of the PLT, and therefore also enjoy the so-called MINLAB structure of the PLT, which has the unit noise-gain property. Other special cases of the GTD-TC are the geometric mean decomposition (GMD) and the bidiagonal decomposition (BID) transform coders. The GMD-TC in particular has the property that the optimum bit allocation is a uniform allocation; this is because all its transform domain coefficients have the same variance, implying thereby that the dynamic ranges of the coefficients to be quantized are identical.
Auteurs: Weng, C.-C.;Chen, C.-Y.;Vaidyanathan, P. P.;
Apparue dans: IEEE Transactions on Signal Processing
Date publication: 02.-2010, volume: 58, issue:2, pages: 566 - 574
Editeur: IEEE
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» Generating Capacity Reliability Evaluation Based on Monte Carlo Simulation and Cross-Entropy Methods
Résumé:
This paper presents a new Monte Carlo simulation (MCS) approach based on cross-entropy (CE) method to evaluate generating capacity reliability (GCR) indices. The basic idea is to use an auxiliary importance sampling density function, whose parameters are obtained from an optimization process that minimizes the computational effort of the MCS estimation approach. In order to improve the performance of the CE-based method as applied to the GCR assessment, various aspects are considered: system size, rarity of the failure event, number of different units, unit capacity sizes, and load shape. The IEEE Reliability Test System is used to test the proposed methodology, and also various modifications of this system are created to fully verify the ability of the proposed approach against both, a crude MCS and an extremely efficient analytical technique based on discrete convolution. A configuration of the Brazilian South-Southeastern generating system is also used to demonstrate the capability of the proposed CE-based MCS method in real applications.
Auteurs: Leite da Silva, A. M.;Fernandez, R. A. G.;Singh, C.;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 02.-2010, volume: 25, issue:1, pages: 129 - 137
Editeur: IEEE
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» Generating Event Sequence-Based Test Cases Using GUI Runtime State Feedback
Résumé:
This paper presents a fully automatic model-driven technique to generate test cases for Graphical user interfaces (GUIs)-based applications. The technique uses feedback from the execution of a “seed test suite,” which is generated automatically using an existing structural event interaction graph model of the GUI. During its execution, the runtime effect of each GUI event on all other events pinpoints event semantic interaction (ESI) relationships, which are used to automatically generate new test cases. Two studies on eight applications demonstrate that the feedback-based technique 1) is able to significantly improve existing techniques and helps identify serious problems in the software and 2) the ESI relationships captured via GUI state yield test suites that most often detect more faults than their code, event, and event-interaction-coverage equivalent counterparts.
Auteurs: Yuan, Xun;Memon, Atif M.;
Apparue dans: IEEE Transactions on Software Engineering
Date publication: 02.-2010, volume: 36, issue:1, pages: 81 - 95
Editeur: IEEE
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» Generation NXT: Building Young Engineers With LEGOs
Résumé:
This paper describes key success factors for the implementation and development of a LEGO robotics engineering outreach program for elementary school students in West Texas. The outreach program not only aims at getting young students excited about engineering but at the same time aims at improving retention rates among electrical and computer engineering freshman-level college students by involving them as paid mentors. It particularly takes into consideration the rural character of West Texas, which provides hardly any electrical and computer engineering job opportunities, and the fact that a university with a college of engineering serves as academic hub for the area.
Auteurs: Karp, T.;Gale, R.;Lowe, L. A.;Medina, V.;Beutlich, E.;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2010, volume: 53, issue:1, pages: 80 - 87
Editeur: IEEE
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» Generation self-scheduling with partial information on the probability distribution of prices
Résumé:
Recent research has shown that generation self-scheduling in electricity markets can be approached using conditional value-at-risk (CVaR). This study considers a worst-case CVaR methodology applicable to cases where only partial information on the underlying probability distribution of prices is given. In particular, the probability distribution is considered under box and ellipsoidal uncertainty structures. It is shown that both structures result in self-scheduling problems that can be formulated as a quadratic cone program. The cone program can be used to (i) compute the worst-case conditional robust profit with probability level β and (ii) optimise the self-schedule for a pre-specified probability β of the corresponding worst-case conditional robust profit. Simulation results are used to demonstrate the self-scheduling model based on the worst-case CVaR. The usefulness of the proposed model is established by contrasting it with the CVaR approach.
Auteurs: Jabr, R.A.;
Apparue dans: IET Generation, Transmission & Distribution
Date publication: 02.-2010, volume: 4, issue:2, pages: 138 - 149
Editeur: IEEE
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» Giant anisotropic magnetoresistance in insulating ultrathin (Ga,Mn)As
Résumé:
Molecular-beam epitaxy grown, 5 nm thick annealed Ga0.95Mn0.05As films demonstrate transition from metallic to insulating state for sheet resistances near resistance quantum, which we connect with the two-dimensional hole localization. Below the metal-insulator transition we found the giant anisotropic magnetoresistance (GAMR) effect, which depends on the orientation of magnetization to crystallographic axes and demonstrates the twofold symmetry angular dependence. The GAMR manifests itself in positive magnetoresistance near 50% at T=1.7 K for H//[110] crystallographic direction in contrast to smaller negative magnetoresistance for H//[110] direction. We connect the GAMR with formation of high- and low-resistance states with different localization due to anisotropic spin-orbit interaction.
Auteurs: Gareev, R. R.;Petukhov, A.;Schlapps, M.;Sadowski, J.;Wegscheider, W.;
Apparue dans: Applied Physics Letters
Date publication: 02.-2010, volume: 96, issue:5, pages: 052114 - 052114-3
Editeur: IEEE
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» Global Communications Newsletter
Résumé:
Includes: International Conference on Regulatory Activities in the Telecommunications Sector 28-29 September 2009, Budva, Montenegro; 2010: An Expected Appointment for DVB-H in Spain and Europe; Recent Activities of the Vietnam Chapter; Activities of the IEEE ComSoc Xi¿an Chapter.
Auteurs: Jevric, B.;Alejos, A.V.;Sanchez, M.G.;Cuinas, I.;Nam, T.X.;Li, J.;
Apparue dans: IEEE Communications Magazine
Date publication: 02.-2010, volume: 48, issue:2, pages: 1 - 4
Editeur: IEEE
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» Global R&D Alliances in China: Collaborations With Universities and Research Institutes
Résumé:
A learning perspective was applied to examining when multinational corporations select universities rather than local firms as partners in international R&D alliances. Data were collected on 327 international R&D alliances established over the 1995--2001 period in China, an emerging economy where intellectual property rights protection is still far from adequate, over the 1995–2001 period. The effects of factors such as the international investor's host country R&D experience and the venture's research objectives on the selection of universities or research institutes as local partners for R&D alliances were analyzed. Analysis using logistic regression models suggests that the contribution of local universities and research institutes to such R&D collaborations is likely to be high when foreign investors have had abundant prior R&D experience in the host country and when the alliance has been established primarily for research rather than development purposes. The implications for theory, practice, and policymaking are discussed.
Auteurs: Li, J. J.;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 02.-2010, volume: 57, issue:1, pages: 78 - 87
Editeur: IEEE
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» Global Transient Stability-Constrained Optimal Power Flow Using an OMIB Reference Trajectory
Résumé:
This paper presents a new approach to transient stability control using global transient stability-constrained optimal power flow (TSC-OPF) methods. Its novelty consists in using the single machine equivalent (SIME) method to perform (and improve) two main important functions of global TSC-OPF approaches: first, SIME is used to efficiently perform the power system transient stability analysis; second, SIME determines a stable one machine infinite bus equivalent rotor angular trajectory that is used as the reference stability constraint, at one specific integration step. In this way, the stability constraint is adjusted by SIME, at each iteration of the TSC-OPF method, in order to accurately reflect power system dynamic behavior. The prowess and main characteristics of the proposed approach are shown by numerical examples.
Auteurs: Pizano-Martianez, A.;Fuerte-Esquivel, C. R.;Ruiz-Vega, D.;
Apparue dans: IEEE Transactions on Power Systems
Date publication: 02.-2010, volume: 25, issue:1, pages: 392 - 403
Editeur: IEEE
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» Glucose biosensor of ruthenium-doped TiO2 sensing electrode by co-sputtering system
Résumé:
In this study, the ruthenium-doped titanium dioxide (TiO2:Ru) sensing film is fabricated by co-sputtering system. The TiO2:Ru sensing film is treated by thermal annealing process at 600°C for 1h in atmosphere. We present a TiO2:Ru-based pH sensor which can obtain the higher sensing value at 64.58mV/pH for the super-Nernstian response. The enzyme composite solution is dropped on the TiO2:Ru sensing film as a glucose biosensor. In the concentration ranging from 100 to 500 (mg/dL) of glucose solution, the sensitivity and linearity of TiO2:Ru sensing film after thermal annealing are 0.320mV(mg/dL)-1 and 0.995, respectively, which is better than non-annealing TiO2:Ru sensing...
Auteurs: Jung-Chuan, Chou , Hung-Yu, Yang , Cheng-Wei, Chen
Apparue dans: Microelectronics Reliability
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» Gold-Nanocluster-Based Fluorescent Sensors for Highly Sensitive and Selective Detection of Cyanide in Water
Résumé:
A novel, gold-nanocluster-based fluorescent sensor for cyanide in aqueous solution, which is based on the cyanide etching-induced fluorescence quenching of gold nanoclusters, is reported. In addition to offering high selectivity due to the unique Elsner reaction between cyanide and the gold atoms of gold nanoclusters, this facile, environmentally friendly and cost-effective method provides high sensitivity. With this sensor, the lowest concentration to quantify cyanide ions could be down to 200 × 10-9 M, which is approximately 14 times lower than the maximum level (2.7 × 10-6 M) of cyanide in drinking water permitted by the World Health Organization (WHO). Furthermore, several real water samples spiked with cyanide, including local groundwater, tap water, pond water, and lake water, are analyzed using the sensing system, and experimental results show that this fluorescent sensor exhibits excellent recoveries (over 93%). This gold-nanocluster-based fluorescent sensor could find applications in highly sensitive and selective detection of cyanide in food, soil, water, and biological samples.
Auteurs: Yanlan Liu, Kelong Ai, Xiaoli Cheng, Lihua Huo, Lehui Lu
Apparue dans: Advanced Functional Materials
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Goodbye, Hello
Résumé:
In this article, IEEE Computer Graphics and Applications' current editor in chief (EIC), Maureen C. Stone, introduces the incoming EIC, Gabriel Taubin.
Auteurs: Stone, Maureen;Taubin, Gabriel;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 02.-2010, volume: 30, issue:1, pages: 6 - 7
Editeur: IEEE
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» GPU-Based Shooting and Bouncing Ray Method for Fast RCS Prediction
Résumé:
The shooting and bouncing ray (SBR) method is highly effective in the radar cross section (RCS) prediction. For electrically large and complex targets, computing scattered fields is still time-consuming in many applications like range profile and ISAR simulation. In this paper, we propose a GPU-based SBR that is fully implemented on the graphics processing unit (GPU). Based on the stackless kd-tree traversal algorithm, the ray tube tracing can rapidly evaluate the exit position in a single pass on the GPU. We also present a technique for fast electromagnetic computing that allows the geometric optics (GO) and Physical optics (PO) integral to be carried out on the GPU efficiently during the ray tube tracing. Numerical experiments demonstrate that the GPU-based SBR can significantly improve the computational efficiency of the RCS prediction, about 30 times faster, while providing the same accuracy as the CPU-based SBR.
Auteurs: Tao, Y.;Lin, H.;Bao, H.;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2010, volume: 58, issue:2, pages: 494 - 502
Editeur: IEEE
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» Gradient-based shape optimisation of conformal array antennas
Résumé:
We present and test a gradient-based shape optimisation method for the minimisation of the active reflection coefficient for conformal array antennas. The goal function is an average of the active reflection coefficient with respect to all antenna elements, a prespecified frequency interval, and a set of excitation modes. The sensitivity of the goal function with respect to changes of the antenna's shape is based on the continuum form of Maxwell's equations, which provides good flexibility for the choice of field solver. The sensitivity is formulated in terms of the field solution of the original antenna problem and a similar adjoint field problem, which gives the sensitivity for an arbitrary number of design parameters given the solution of Maxwell's equations. We test the optimisation method in two dimensions for array antennas that conform to a circular cylinder, where both uniform arrays and arrays that occupy a part of the cylinder's circumference are considered. For some cases, we find that it is feasible to reduce the active reflection coefficient for arrays that partially cover the circumference of the cylinder by means of end elements that differ from the bulk elements of the array. In general, substantial reductions in the active reflection coefficient can be achieved by relatively small shape changes of the antenna elements. For the test cases considered in this article, the optimisation method typically converges to an optimised design within 5-15 iterations.
Auteurs: Jacobsson, P.;Rylander, T.;
Apparue dans: IET Microwaves, Antennas & Propagation
Date publication: 02.-2010, volume: 4, issue:2, pages: 200 - 209
Editeur: IEEE
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» Gradient-Like Observers for Invariant Dynamics on a Lie Group
Résumé:
This paper proposes a design methodology for non-linear state observers for invariant kinematic systems posed on finite dimensional connected Lie groups, and studies the associated fundamental system structure. The concept of synchrony of two dynamical systems is specialized to systems on Lie groups. For invariant systems this leads to a general factorization theorem of a nonlinear observer into a synchronous (internal model) term and an innovation term. The synchronous term is fully specified by the system model. We propose a design methodology for the innovation term based on gradient-like terms derived from invariant or non-invariant cost functions. The resulting nonlinear observers have strong (almost) global convergence properties and examples are used to demonstrate the relevance of the proposed approach.
Auteurs: Lageman, C.;Trumpf, J.;Mahony, R.;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2010, volume: 55, issue:2, pages: 367 - 377
Editeur: IEEE
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» Graphene-Polymer Nanofiber Membrane for Ultrafast Photonics
Résumé:
A freestanding membrane composed of a nanofiber network of a graphene-polymer nanocomposite is fabricated by electrospinning and applied as an optical element in fiber lasers. The functionalization of graphene with conjugated organic molecules provides a handle for improving mechanical and thermal properties as well as tuning the optical properties. A small loading (0.07 wt%) of functionalized graphene enhances the total optical absorption of poly(vinyl acetate) (PVAc) by 10 times. The electrospun graphene-polymer nanocomposites exhibit wideband saturable absorbance for laser pulse shaping, and attain a larger modulation depth and smaller nonsaturable loss than single-walled carbon nanotubes. The results show that electrospun graphene nanocomposites are promising candidates as practical and efficient photonic materials for the generation of ultrashort pulses in fiber lasers.
Auteurs: Qiaoliang Bao, Han Zhang, Jia-xiang Yang, Shuai Wang, Ding Yuan Tang, Rajan Jose, Seeram Ramakrishna, Chwee Teck Lim, Kian Ping Loh
Apparue dans: Advanced Functional Materials
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Green-building guru
Résumé:
He works with architects to design sustainable buildings. Henrik Sorensen was 25 years old when a career counselor asked him to describe his dream job to a room full of unemployed engineers. "To work in solar energy on the southern part of Fyn,"Sørensen replied, referring to the Danish island where his father was born.
Auteurs: Upson, S.;
Apparue dans: IEEE Spectrum
Date publication: 02.-2010, volume: 47, issue:2, pages: 38 - 39
Editeur: IEEE
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» Greetings from the 2010 President [Presidents Column]
Résumé:
It is a great honor for me to serve as the 2010 MTT-S president! It is a nice surprise too. As I sat down to write this column, I could not help but to reminisce about my first involvement with the MTT Society.
Auteurs: El-Ghazaly, S.;
Apparue dans: IEEE Microwave Magazine
Date publication: 02.-2010, volume: 11, issue:1, pages: 18 - 22
Editeur: IEEE
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» Greetings [President's Perspectives]
Résumé:
I am honored to serve as president of the IEEE Instrumentation and Measurement (I&M) Society. I follow in the giant footsteps of very capable presidents, vice presidents, and members of the Administrative Committee (AdCom). I count the recent past presidents, Alessandro Ferrero, Steve Dyer, Bob Rassa, and Brian Wadell, as mentors and friends. They represent just a few of the folks that I highly esteem as insightful, caring, and dedicated volunteers within our society. Our society has a storied past, a vibrant present, and a hopeful future. I am delighted to have been and to be involved with you in all three eras.
Auteurs: Fowler, K.;
Apparue dans: IEEE Instrumentation & Measurement Magazine
Date publication: 02.-2010, volume: 13, issue:1, pages: 6 - 6
Editeur: IEEE
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» Griffiths phase and exchange bias in La1-xCaxMnO3 (x=0.50, 0.67, and 0.75) nanoparticles
Résumé:
The magnetic properties of La1-xCaxMnO3 (x=0.50, 0.67, and 0.75) nanoparticles have been systemically investigated in this work. It is found that although their bulk counterparts have different magnetic and charge ordered states, the nanoparticles show no long-range charge ordered transition but very similar magnetic behaviors, i.e., a Griffiths phase appearing below ∼300 K and a ferromagnetic ordered state present below ∼270 K. The similarity suggests that the enhanced ferromagnetic behavior at low temperatures in the nanoparticles may originate from the development of the ferromagnetic correlations already present at high temperature upon cooling due to the suppression of the charge ordered state. Moreover, the field-cooling magnetic hysteresis loops reveal that exchange bias phenomena are present in the nanoparticles, which is of special interest for potential applications.
Auteurs: Zhou, S. M.;Zhao, S. Y.;Guo, Y. Q.;Zhao, J. Y.;Shi, L.;
Apparue dans: Journal of Applied Physics
Date publication: 02.-2010, volume: 107, issue:3, pages: 033906 - 033906-5
Editeur: IEEE
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» Growing Self-Reconstruction Maps
Résumé:
In this paper, we propose a new method for surface reconstruction based on growing self-organizing maps (SOMs), called growing self-reconstruction maps (GSRMs). GSRM is an extension of growing neural gas (GNG) that includes the concept of triangular faces in the learning algorithm and additional conditions in order to include and remove connections, so that it can produce a triangular two-manifold mesh representation of a target object given an unstructured point cloud of its surface. The main modifications concern competitive Hebbian learning (CHL), the vertex insertion operation, and the edge removal mechanism. The method proposed is able to learn the geometry and topology of the surface represented in the point cloud and to generate meshes with different resolutions. Experimental results show that the proposed method can produce models that approximate the shape of an object, including its concave regions, boundaries, and holes, if any.
Auteurs: Rego, R. L. M. E.;Araujo, A. F. R.;de Lima Neto, F. B.;
Apparue dans: IEEE Transactions on Neural Networks
Date publication: 02.-2010, volume: 21, issue:2, pages: 211 - 223
Editeur: IEEE
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» Growth and characterization of In-polar and N-polar InAlN by metal organic chemical vapor deposition
Résumé:
InxAl1-xN layers, with 0.09≤x≤0.23, were grown on GaN on both the In-polar and N-polar orientations by metal organic chemical vapor deposition. The impact of growth conditions, including temperature and the group-III flow rates, on the surface morphology and indium mole fraction was investigated. In-polar layers had a smooth surface morphology characterized by mounds which decreased in size with increasing supersaturation during growth. Smooth N-polar InAlN was achieved through the use of vicinal sapphire substrates with misorientation angles of 3°–5° toward <1010>GaN, and a trend of an increase in step bunching with decreasing supersaturation was observed for N-polar InAlN layers. The indium incorporation increased with decreasing growth temperature and increasing growth rate for both In-polar and N-polar layers. The indium incorporation was similar for both orientations on samples which were coloaded in our reactor.
Auteurs: Brown, David F.;Keller, Stacia;Mates, Thomas E.;Speck, James S.;DenBaars, Steven P.;Mishra, Umesh K.;
Apparue dans: Journal of Applied Physics
Date publication: 02.-2010, volume: 107, issue:3, pages: 033509 - 033509-7
Editeur: IEEE
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» Growth of GaN LED Structure on Si Substrate by MBE and Monolithic Fabrication of GaN LED Cooling System
Résumé:
GaN-based light emitting diodes (LEDs) were fabricated by molecular beam epitaxy (MBE) on a GaN/Si substrate prepared by metal organic chemical vapor deposition (MOCVD). Blue light emission was obtained at the peak wavelength of 410 nm. An integration of GaN LEDs and a cooling system is proposed. GaN membrane structure with Si microchannels was fabricated from the GaN/Si substrate. A preliminary experiment for the proposed device was carried out. Copyright © 2010 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Auteurs: Masashi Wakui, Fang-Ren Hu, Hidehisa Sameshima, Kazuhiro Hane
Apparue dans: IEEJ Transactions on Electrical and Electronic Engineering
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Guest Editor's Introduction: Renewing the Software Project Management Life Cycle
Résumé:
When a project has concluded, the computers turned off, the source files archived, and the personnel reassigned, how do you measure its success? IT managers have suspected for a long time that a successful software project doesn't just deliver the right system built the right way, but rather makes other kinds of contributions to enriching the enterprise, such as providing personnel with valuable training and experience. Much of the renewed interest in project retrospectives is rooted in the realization that success isn't just about building the system, but learning from the experience, and managers haven't done their jobs if they haven't captured those benefits, too. The idea that a successful software project also generates intangible benefits for the enterprise has been around for a while, but we're seeing renewed interest in the discipline of intellectual capital reporting. The New Club of Paris is bringing intellectual capital reporting to the attention of IT managers and even national governments as a fundamental tool in their strategies for remaining competitive in the knowledge society. These new approaches to software project evaluation and measurement illustrate how some of our most sacred tenets are coming under scru-tiny-including the very principle of software measurement itself. Last year, Tom de Marco wondered whether his influential management maxim, "you can't control what you can't measure," introduced over three decades ago, needs revision in view of today's value-oriented IT environment.
Auteurs: Favaro, J.;
Apparue dans: IEEE Software
Date publication: 02.-2010, volume: 27, issue:1, pages: 17 - 19
Editeur: IEEE
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» Guest Editorial
Résumé:
Auteurs: Nam, G.-J.;Saxena, P.;
Apparue dans: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Date publication: 02.-2010, volume: 29, issue:2, pages: 169 - 170
Editeur: IEEE
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» Guest Editorial
Résumé:
The 12 papers in this special section were originally presented at the 13th International EPE-PEMC Conference in Poznan, Poland, in September 2008.
Auteurs: Kazmierkowski, M. P.;Nagy, I.;Zawirski, K.;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 02.-2010, volume: 57, issue:2, pages: 466 - 467
Editeur: IEEE
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» Guest Editorial Data Communication Techniques for Storage Channels and Networks
Résumé:
Since the inception of direct access magnetic storage about 55 years ago, data storage has both benefited from and given rise to extraordinary progress in many technological areas, including materials science, tribology, servo control and actuation, and signal processing and coding. The number of data bits that can be stored in a unit area ¿ the areal recording density ¿ has increased by eight orders of magnitude for harddisk magnetic storage, with compound annual growth rates at times exceeding 100%. Moreover, the cost of this form of storage has dropped by about seven orders of magnitude. For this reason, data storage has been one of the main enablers of the information technology revolution. According to a recent estimation by the technology analysis firm IDC, the amount of data created worldwide has now started to exceed the capacity of storage that is physically available. This so-called digital universe is forecasted to grow explosively and reach more than 1021 bytes (1 ZB) in 2011.
Auteurs: Olcer, S.;Kavcic, A.;Vasic, B.;Wilson, B.;Xu, L.;
Apparue dans: IEEE Journal on Selected Areas in Communications
Date publication: 02.-2010, volume: 28, issue:2, pages: 129 - 134
Editeur: IEEE
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» Guest Editorial Special Section on Industrial Control
Résumé:
Auteurs: Ho, W. K.;Qin, S. J.;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2010, volume: 6, issue:1, pages: 1 - 2
Editeur: IEEE
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» Guest editorial: Special issue on neuroimaging
Résumé:
No abstract.
Auteurs: Dae-Shik Kim
Apparue dans: International Journal of Imaging Systems and Technology
Date publication: 02.-2010
Editeur: Wiley InterScience
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» Guest Editorial: Special Issue on Outreach to Prospective Electrical, Electronics, and Computer Engineering Students
Résumé:
Auteurs: Tan, K. K.;Genalo, L. J.;Verner, I. M.;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2010, volume: 53, issue:1, pages: 1 - 2
Editeur: IEEE
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» Guest Editors' Introduction: Confronting the Hardware Trustworthiness Problem
Résumé:
The emergence of a globalized, horizontal semiconductor business model raises concerns involving the security and trust of the information systems on which modern society is increasingly reliant for mission-critical functionality. Traditionally, hardware-based security techniques and countermeasures modify hardware to prevent attacks and to protect IP blocks or secret keys. Some of the emerging types of attacks covered by this special issue are fundamentally different: the attacker is assumed to maliciously alter the design before or during fabrication.
Auteurs: Tehranipoor, Mohammad;Koushanfar, Farinaz;
Apparue dans: IEEE Design & Test of Computers
Date publication: 02.-2010, volume: 27, issue:1, pages: 8 - 9
Editeur: IEEE
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» Guest Editors' Introduction: Knowledge-Assisted Visualization
Résumé:
This special issue presents four articles demonstrating a first step from traditional interactive visualization to knowledge-assisted visualization. Knowledge-assisted visualization's objectives include sharing domain knowledge among different users and reducing the burden on users to acquire knowledge about complex visualization techniques. The four articles address this new challenge from different perspectives, including methodologies, systems, and applications.
Auteurs: Chen, Min;Hagen, Hans;
Apparue dans: IEEE Computer Graphics and Applications
Date publication: 02.-2010, volume: 30, issue:1, pages: 15 - 16
Editeur: IEEE
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» Guidelines for the placement of fiducial points in image-guided neurosurgery
Résumé:
Point-pair registration is widely used to register the patient and the image space in image-guided neurosurgery. The registration accuracy at the target point is influenced by the distribution of the fiducial points, and it is not always easy to achieve a good distribution in clinical practice.We propose one original configuration and three variants of the distribution of the fiducial points, in which each fiducial point has a definite position on the head surface. These configurations are conceived by considering both the theoretical value of the target registration error (TRE) and practical constraints on the positioning of the fiducial points. These configurations can guide the surgeon to place fiducial points directly onto the patient's head.Experiments with real clinical data showed that when using the original configuration, the TRE in the whole skull was < 2 mm and the TRE in the whole brain was < 1.5 mm if the fiducial registration error was 2.5 mm. When using variants of the original configuration, small TRE can also be achieved in the corresponding surgical field.This study provides an easy-to-use approach to achieving good distribution of fiducial points in image-guided neurosurgery. Copyright © 2010 John Wiley & Sons, Ltd.
Auteurs: Manning Wang, Zhijian Song
Apparue dans: The International Journal of Medical Robotics and Computer Assisted Surgery
Date publication: 02.-2010
Editeur: Wiley InterScience
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» H-Infinity State Feedback Control for a Class of Networked Cascade Control Systems With Uncertain Delay
Résumé:
Based on practical industrial process control, a typical configuration for networked cascade control systems (NCCSs) is analyzed. This kind of NCCSs with state feedback controllers, in which the network-induced delay is uncertain and less than a sampling period, is studied. The sufficient condition for the stabilizability of the NCCSs without disturbances is proposed, and the state feedback stabilization control laws are derived via Lyapunov stability theory and linear matrix inequality (LMI) approach. For the NCCSs with disturbances, the criterion of its robust asymptotically stability is derived and the -suboptimal state feedback control laws are designed. The -optimal state feedback control laws are also put forward by optimizing a set of LMIs. A simulation example of a NCCS for the main steam temperature in a power plant is given to demonstrate the effectiveness of the proposed approaches.
Auteurs: Huang, C.;Bai, Y.;Liu, X.;
Apparue dans: IEEE Transactions on Industrial Informatics
Date publication: 02.-2010, volume: 6, issue:1, pages: 62 - 72
Editeur: IEEE
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» Hacking for humanity
Résumé:
He brings the hacker ethic and Internet access to the far corners of the globe. He attained geek immortality by coinventing the Sol-­20 personal computer in the mid-­1970s. He was a key member of the legendary Homebrew Computer Club and a recurring character in Steven Levy's 1984 book, Hackers. So you'd think that nowadays Bob Marsh might be tripping the light fantastic like fellow personal-­computer pioneer Steve Wozniak, or at least kicking back and enjoying retirement.
Auteurs: Goldstein, H.;
Apparue dans: IEEE Spectrum
Date publication: 02.-2010, volume: 47, issue:2, pages: 33 - 34
Editeur: IEEE
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» Hands-On Experience in HPC With Secondary School Students
Résumé:
It is a global concern that the number of students in computing-related fields has been decreasing in the last few years. As a way to improve this situation, several institutions have been implementing programs to attract and keep students in science and technology majors. This work describes a high-performance computing (HPC) course intended for secondary school students, which requires only the most basic infrastructure. In this hands-on workshop, the students learn how to assemble, install, and test a cluster. In parallel, students are exposed to a complete new area of knowledge, obtaining a more accurate view of the discipline of computer science and increasing their confidence in their ability to follow computer science. This course also provides opportunities for students to meet scientists and lose any misconceptions and negative stereotypes about science in general and computer science in particular. The aim of this paper is to detail the key concepts conveyed to students, share the course organization, materials, and examples used, and describe the overall experience.
Auteurs: Fernandez Slezak, D.;Turjanski, P. G.;Montaldo, D.;Mocskos, E. E.;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2010, volume: 53, issue:1, pages: 128 - 135
Editeur: IEEE
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» Hands-On Summer Camp to Attract K–12 Students to Engineering Fields
Résumé:
This paper explains the organization and execution of a summer engineering outreach camp designed to attract and motivate high school students as well as increase their awareness of various engineering fields. The camp curriculum included hands-on, competitive design-oriented engineering projects from several disciplines: the electrical, environmental, mechanical, civil, and chemical engineering fields. The camp also provided additional information on financial aid, the academic programs in the fields of science, technology, engineering, and math (STEM) offered at Texas A&M University–Kingsville (TAMUK), as well as various career options for prospective engineers. The implementation of the camp activities and the well-designed hands-on projects not only increased the students' satisfaction, but also improved their self-confidence and their interest toward engineering disciplines. The engineering outreach camp survey results clearly indicated the success of the camp and the effectiveness of the hands-on, competitive engineering design experiences to attract students to engineering professions. Thus, it demonstrated an effective, feasible, and sustainable engineering recruitment approach.
Auteurs: Yilmaz, M.;Ren, J.;Custer, S.;Coleman, J.;
Apparue dans: IEEE Transactions on Education
Date publication: 02.-2010, volume: 53, issue:1, pages: 144 - 151
Editeur: IEEE
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» Hardware Trojans in Wireless Cryptographic ICs
Résumé:
Editor's note:This article studies the problem of hardware Trojans in wireless cryptographic ICs. The objective is to design Trojans to leak secret information through the wireless channel. The authors investigate challenges related to detection for such Trojans and propose using statistical analysis of the side-channel signals to help detect them.&#x2014;Mohammad Tehranipoor, University of Connecticut
Auteurs: Jin, Yier;Makris, Yiorgos;
Apparue dans: IEEE Design & Test of Computers
Date publication: 02.-2010, volume: 27, issue:1, pages: 26 - 35
Editeur: IEEE
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» Hardware/Software Codesign of a Low-Cost Rate Control Scheme for H.264/AVC
Résumé:
This paper presents a low-complexity rate control (RC) framework for H.264/advanced video coding (AVC) encoders on embedded systems. We consider not only the rate-distortion performance but also its implementation complexity using an efficient hardware/software codesign. The proposed cost-effective macroblock level RC module works in hardware, and the frame-level RC is executed on the system CPU as software. It is less complex than the RC module adopted by H.264/AVC JM reference software, making it more suitable for embedded systems. Experiment results show that the proposed RC outperforms H.264/AVC JM, and the hardware implementation cost is low for an H.264/AVC video encoder.
Auteurs: Kuo, C.-H.;Chang, L.-C.;Fan, K.-W.;Liu, B.-D.;
Apparue dans: IEEE Transactions on Circuits and Systems for Video Technology
Date publication: 02.-2010, volume: 20, issue:2, pages: 250 - 261
Editeur: IEEE
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» Hazard-Based Detection Conditions for Improved Transition Fault Coverage of Scan-Based Tests
Résumé:
We define a new type of detection conditions for delay faults, referred to as hazard-based detection conditions, to enhance the coverage of delay faults using the standard scan test application methods. Some delay faults, including irredundant faults, may be undetectable under the conventional detection conditions. These faults may be detectable under the hazard-based detection conditions. The use of hazard-based detection conditions thus improves the delay fault coverage achievable for a circuit. We consider transition faults under standard scan for the study in this paper.
Auteurs: Pomeranz, I.;Reddy, S. M.;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 02.-2010, volume: 18, issue:2, pages: 333 - 337
Editeur: IEEE
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» Hermite-Rodriguez UWB Circular Arrays
Résumé:
Pulsed circular arrays are collecting growing interest in radar applications such as automotives and indoor navigations. This contribution presents the analytic derivation of the space-time and energy patterns of pulsed circular arrays in terms of geometrical and electrical parameters as well as of the signal distortion produced by the antennas' response. It is shown that the field emitted by circular arrays with many elements can be represented as a summation of a practically finite set of high-order Hermite-Rodriguez waveforms, while the energy pattern is a generalized Hypergeometric Function. The angular and temporal resolutions are finally related, through handy formulas, to the array size, the input signals and to the antenna types.
Auteurs: Marrocco, G.;Galletta, G.;
Apparue dans: IEEE Transactions on Antennas and Propagation
Date publication: 02.-2010, volume: 58, issue:2, pages: 381 - 390
Editeur: IEEE
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» Heterogeneous Networking: An Enabling Paradigm for Ubiquitous Wireless Communications
Résumé:
Auteurs: Akhtman, J.;Hanzo, L.;
Apparue dans: Proceedings of the IEEE
Date publication: 02.-2010, volume: 98, issue:2, pages: 135 - 138
Editeur: IEEE
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» Hierarchical Cluster-Based Multispecies Particle-Swarm Optimization for Fuzzy-System Optimization
Résumé:
This paper proposes a hierarchical cluster-based multispecies particle-swarm optimization (HCMSPSO) algorithm for fuzzy-system optimization. The objective of this paper is to learn Takagi–Sugeno–Kang (TSK) type fuzzy rules with high accuracy. In the HCMSPSO-designed fuzzy system (FS), each rule defines its own fuzzy sets, which implies that the number of fuzzy sets for each input variable is equal to the number of fuzzy rules. A swarm in HCMSPSO is clustered into multiple species at an upper hierarchical level, and each species is further clustered into multiple subspecies at a lower hierarchical level. For an FS consisting of rules, species (swarms) are formed in the upper level, where one species optimizes a single fuzzy rule. Initially, there are no species in HCMSPSO. An online cluster-based algorithm is proposed to generate new species (fuzzy rules) automatically. In the lower layer, subspecies within the same species are formed adaptively in each iteration during the particle update. Several simulations are conducted to verify HCMSPSO performance. Comparisons with other neural learning, genetic, and PSO algorithms demonstrate the superiority of HCMSPSO performance.
Auteurs: Juang, C.-F.;Hsiao, C.-M.;Hsu, C.-H.;
Apparue dans: IEEE Transactions on Fuzzy Systems
Date publication: 02.-2010, volume: 18, issue:1, pages: 14 - 26
Editeur: IEEE
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» Hierarchical Segmentation of R&D Process and Intellectual Property Protection: Evidence From Multinational R&D Laboratories in China
Résumé:
This paper examines how multinational corporations (MNCs) protect their intellectual property (IP) when they conduct R&D in countries with weak IP rights (IPRs) protection. Findings from a small-scale survey and three case studies in China show that hierarchical segmentation of the R&D process can provide an effective way for IPR protection. Furthermore, a modular R&D structure adopted by many information technology companies can facilitate the hierarchical segmentation. Because R&D is becoming distributed across locations with varying levels of IPR protection, a center-peripheral R&D organizational structure is emerging within MNCs as R&D globalization proceeds.
Auteurs: Quan, X.;Chesbrough, H.;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 02.-2010, volume: 57, issue:1, pages: 9 - 21
Editeur: IEEE
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» High capacity lossless data embedding technique for palette images based on histogram analysis
Résumé:
Recently data embedding over images has drawn tremendous interest, using either lossy or lossless techniques. Although lossy techniques can allow large hiding capacity, host image cannot be recovered with high fidelity. Some applications require exact recovery of the host image, i.e. in medicine patient data can be embedded without affecting the medical image. In general lossless data hiding techniques suffer from limited capacity as the host image should be kept intact. In this paper a lossless embedding technique is proposed. In this technique image histograms are analyzed to identify the embedding capacity of different image types. Histogram maxima and minima...
Auteurs: Noura A., Saleh , Hoda N., Boghdady , Samir I., Shaheen , Ahmed M., Darwish
Apparue dans: Digital Signal Processing
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» High capacity SMVQ-based hiding scheme using adaptive index
Résumé:
This paper proposes a high-capacity image-hiding scheme based on an adaptive index. Data-hiding based on vector quantization (VQ) is a technique for hiding data in the VQ index code. Data-hiding based on side match vector quantization (SMVQ) has been proposed for improving the compression rate of VQ-based data-hiding schemes. However, the hiding capacity of an SMVQ-based data-hiding scheme is very low since, at most, only one secret bit is hidden in one index code. To overcome this drawback and increase capacity, the proposed method uses an adaptive index to hide more bits in one index code. The weighted squared Euclidean...
Auteurs: Chang-Chu, Chen , Chin-Chen, Chang
Apparue dans: Signal Processing
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» High density conics in a magnetically expanding helicon plasma
Résumé:
A two-dimensional mapping of ion density and plasma potential in a diverging magnetized low pressure (0.4 mTorr) carbon dioxide helicon plasma containing a double layer reveals the presence of high density conics (∼7×109 cm-3) along the most diverging magnetic field lines exiting the helicon source and connecting with the grounded expansion chamber. The density in the conic is about 30% greater than the density at the double layer and this results from local ionization associated with the presence of a high energy tail in the electron energy probability function. The plasma potential along the conic is constant at about 30 V.
Auteurs: Charles, C.;
Apparue dans: Applied Physics Letters
Date publication: 02.-2010, volume: 96, issue:5, pages: 051502 - 051502-3
Editeur: IEEE
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» High efficient organic ultraviolet photovoltaic devices based on gallium complex
Résumé:
High efficient organic ultraviolet (UV) photovoltaic devices comprising 4,4?,4?-tri-(2-methylphenyl phenylamino) triphenylamine (m-MTDATA) and tris-(8-hydroxyquinoline) gallium (Gaq3) as the electron donor and acceptor, respectively, are demonstrated. The m-MTDATA/Gaq3 bilayer device shows a short-circuit current density of 59.3?A/cm2, a open-circuit voltage of 1.85V, a fill factor of 0.41, and a power conversion efficiency of 3.74% under illumination of a 1.2mW/cm2 365nm UV light. And this power conversion efficiency is superior than that of the device based on tris-(8-hydroxyquinoline) aluminum with the same device structure, which is attributed to the high electron mobility of Gaq3 and the low exciton loss via radiation decay...
Auteurs: Zisheng, Su , Bei, Chu , Wenlian, Li
Apparue dans: Solid-State Electronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» High Ge Content of SiGe Channel pMOSFETs on Si (110) Surfaces
Résumé:
The characteristics of channel PFETs fabricated directly on Si (110) surfaces have been investigated. The saturation drain current and the hole mobility of a (110) PFET are enhanced by 70% and by 80% for the channel, as compared with that of a bulk Si (110) PFET. For comparison with a Si (100) PFET, a SiGe PFET has 200% hole mobility enhancement. The performance difference of the and PFET is about 2.7 times when considering mobility, and these effects are explained.
Auteurs: Lee, M. H.;Chang, S. T.;Maikap, S.;Peng, C.-Y.;Lee, C.-H.;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2010, volume: 31, issue:2, pages: 141 - 143
Editeur: IEEE
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» High Microwave-Noise Performance of AlGaN/GaN MISHEMTs on Silicon With Gate Insulator Grown by ALD
Résumé:
High microwave-noise performance is realized in AlGaN/GaN metal–insulator semiconductor high-electron mobility transistors (MISHEMTs) on high-resistivity silicon substrate using atomic-layer-deposited (ALD) as gate insulator. The ALD MISHEMT with a 0.25- gate length shows excellent microwave small signal and noise performance. A high current-gain cutoff frequency of 40 GHz and maximum oscillation frequency of 76 GHz were achieved. At 10 GHz, the device exhibits low minimum-noise figure of 1.0 dB together with high associate gain of 10.5 dB and low equivalent noise resistance of 29.2 . This is believed to be the first report of a 0.25- gate-length GaN MISHEMT on silicon with such microwave-noise performance. These results indicate that the AlGaN/GaN MISHEMT with ALD gate insulator on high-resistivity Si substrate is suitable for microwave low-noise applications.
Auteurs: Liu, Z. H.;Ng, G. I.;Arulkumaran, S.;Maung, Y. K. T.;Teo, K. L.;Foo, S. C.;Sahmuganathan, V.;Xu, T.;Lee, C. H.;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2010, volume: 31, issue:2, pages: 96 - 98
Editeur: IEEE
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» High Microwave-Noise Performance of AlGaN/GaN MISHEMTs on Silicon With Gate Insulator Grown by ALD
Résumé:
High microwave-noise performance is realized in AlGaN/GaN metal–insulator semiconductor high-electron mobility transistors (MISHEMTs) on high-resistivity silicon substrate using atomic-layer-deposited (ALD) as gate insulator. The ALD MISHEMT with a 0.25- gate length shows excellent microwave small signal and noise performance. A high current-gain cutoff frequency of 40 GHz and maximum oscillation frequency of 76 GHz were achieved. At 10 GHz, the device exhibits low minimum-noise figure of 1.0 dB together with high associate gain of 10.5 dB and low equivalent noise resistance of 29.2 . This is believed to be the first report of a 0.25- gate-length GaN MISHEMT on silicon with such microwave-noise performance. These results indicate that the AlGaN/GaN MISHEMT with ALD gate insulator on high-resistivity Si substrate is suitable for microwave low-noise applications.
Auteurs: Liu, Z. H.;Ng, G. I.;Arulkumaran, S.;Maung, Y. K. T.;Teo, K. L.;Foo, S. C.;Sahmuganathan, V.;Xu, T.;Lee, C. H.;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2010, volume: 31, issue:2, pages: 96 - 98
Editeur: IEEE
Document complet vers site de l'éditeur
 
» High Microwave-Noise Performance of AlGaN/GaN MISHEMTs on Silicon With Gate Insulator Grown by ALD
Résumé:
High microwave-noise performance is realized in AlGaN/GaN metal–insulator semiconductor high-electron mobility transistors (MISHEMTs) on high-resistivity silicon substrate using atomic-layer-deposited (ALD) as gate insulator. The ALD MISHEMT with a 0.25- gate length shows excellent microwave small signal and noise performance. A high current-gain cutoff frequency of 40 GHz and maximum oscillation frequency of 76 GHz were achieved. At 10 GHz, the device exhibits low minimum-noise figure of 1.0 dB together with high associate gain of 10.5 dB and low equivalent noise resistance of 29.2 . This is believed to be the first report of a 0.25- gate-length GaN MISHEMT on silicon with such microwave-noise performance. These results indicate that the AlGaN/GaN MISHEMT with ALD gate insulator on high-resistivity Si substrate is suitable for microwave low-noise applications.
Auteurs: Liu, Z. H.;Ng, G. I.;Arulkumaran, S.;Maung, Y. K. T.;Teo, K. L.;Foo, S. C.;Sahmuganathan, V.;Xu, T.;Lee, C. H.;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2010, volume: 31, issue:2, pages: 96 - 98
Editeur: IEEE
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» High mobility orthogonal frequency division multiple access channel estimation using basis expansion model
Résumé:
Owing to the loss of subcarrier orthogonalities in high-speed applications, the use of conventional frequency-domain-based channel estimation in high mobility orthogonal frequency division multiple access (OFDMA) systems such as mobile WiMax may give rise to an unacceptable high channel estimation error floor. To alleviate this problem, the authors develop some basis expansion model (BEM)-based estimation schemes for the OFDMA uplink. Specifically, the authors express the time-varying channel as a superposition of a small number of complex exponential basis functions spanning the entire Doppler range, and then formulate least square (LS) and linear minimum mean square error (LMMSE) algorithms to estimate the basis coefficients for two different types of pilot patterns. The authors also derive the respective Cramer-Rao lower bounds for these estimators. It has been shown that the time domain BEM using a pilot scheme where pilots are placed over time axis will give better performance under a high Doppler scenario. Lastly, using simulation results, the proposed algorithms have been found to have better estimation accuracy over current frequency domain estimation techniques. This is in addition to the advantage that the proposed algorithms have in general a lower computational complexity.
Auteurs: Rabbi, M.F.;Hou, S.-W.;Ko, C.C.;
Apparue dans: IET Communications
Date publication: 02.-2010, volume: 4, issue:3, pages: 353 - 367
Editeur: IEEE
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» High speed infrared camera diagnostic for heat flux measurement in NSTX
Résumé:
A new high speed infrared camera has been successfully implemented and produced first set of heat flux measurements on the lower divertor tiles in the NSTX tokamak. High spatial and temporal resolutions, 6.4 mm and 1.6–6.3 kHz, respectively, enable us to investigate detailed structure of heat flux deposition pattern caused by transient events such as edge localized modes. A comparison of the data with a slow infrared camera viewing the same region of interest shows good agreement between the two independent measurements. Data analysis for various plasma conditions is in progress.
Auteurs: Ahn, J.-W.;Maingi, R.;Mastrovito, D.;Roquemore, A. L.;
Apparue dans: Review of Scientific Instruments
Date publication: 02.-2010, volume: 81, issue:2, pages: 023501 - 023501-4
Editeur: IEEE
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» High TX-to-RX Isolation in UHF RFID Using Narrowband Leaking Carrier Canceller
Résumé:
Ultra-high frequency (UHF) radio frequency identification (RFID) system suffers from large leakage of the carrier due to insufficient TX-to-RX isolation. A narrowband leaking carrier canceller (LCC) for UHF RFID is proposed to enhance the isolation. Hardware realization is carried out based on simulation model in ADS (Advanced Design System). Measurement results indicate that the TX-to-RX isolation is improved from 20 dB to above 40 dB within UHF RFID frequency band of 920–925 MHz. Upper limit of increase in isolation versus amplitude and phase distortion are also presented and discussed.
Auteurs: Xiong, T.;Tan, X.;Xi, J.;Min, H.;
Apparue dans: IEEE Microwave and Wireless Components Letters
Date publication: 02.-2010, volume: 20, issue:2, pages: 124 - 126
Editeur: IEEE
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» High- RF-MEMS 4–6-GHz Tunable Evanescent-Mode Cavity Filter
Résumé:
This paper presents a miniature high- tunable evanescent-mode cavity filter using planar capacitive RF microelectromechanical system (MEMS) switch networks and with a frequency coverage of 4.07–5.58 GHz. The two-pole filter, with an internal volume of 1.5 cm , results in an insertion loss of 4.91–3.18- and a 1-dB bandwidth of 17.8–41.1 MHz, respectively, and an ultimate rejection of 80 dB. RF-MEMS switches with digital/analog tuning capabilities were used in the tunable networks so as to align the two poles together and result in a near-ideal frequency response. The measured of the filter is 300–500 over the tuning range, which is the best reported using RF-MEMS technology. The filter can withstand an acceleration of 55–110 g without affecting its frequency response. The topology can be extended to a multiple-pole design with the use of several RF-MEMS tuning networks inside the evanescent-mode cavity. To our knowledge, these results represent the state-of-the-art in RF-MEMS tunable filters.
Auteurs: Park, S.-J.;Reines, I.;Patel, C.;Rebeiz, G. M.;
Apparue dans: IEEE Transactions on Microwave Theory and Techniques
Date publication: 02.-2010, volume: 58, issue:2, pages: 381 - 389
Editeur: IEEE
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» High-Efficiency Isolated Boost DC–DC Converter for High-Power Low-Voltage Fuel-Cell Applications
Résumé:
A new design approach achieving very high conversion efficiency in low-voltage high-power isolated boost dc–dc converters is presented. The transformer eddy-current and proximity effects are analyzed, demonstrating that an extensive interleaving of primary and secondary windings is needed to avoid high winding losses. The analysis of transformer leakage inductance reveals that extremely low leakage inductance can be achieved, allowing stored energy to be dissipated. Power MOSFETs fully rated for repetitive avalanches allow primary-side voltage clamp circuits to be eliminated. The oversizing of the primary-switch voltage rating can thus be avoided, significantly reducing switch-conduction losses. Finally, silicon carbide rectifying diodes allow fast diode turn-off, further reducing losses. Detailed test results from a 1.5-kW full-bridge boost dc–dc converter verify the theoretical analysis and demonstrate very high conversion efficiency. The efficiency at minimum input voltage and maximum power is 96.8%. The maximum efficiency of the proposed converter is 98%.
Auteurs: Nymand, M.;Andersen, M. A. E.;
Apparue dans: IEEE Transactions on Industrial Electronics
Date publication: 02.-2010, volume: 57, issue:2, pages: 505 - 514
Editeur: IEEE
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» High-Efficiency Soft-Error-Tolerant Digital Signal Processing Using Fine-Grain Subword-Detection Processing
Résumé:
The soft error problem in digital circuits is becoming increasingly important as the IC fabrication technology progresses from the deep submicrometer scale to the nanometer scale. This paper proposes a subword-detection processing (SDP) technique and a fine-grain soft-error-tolerance (FGSET) architecture to improve the performance of the digital signal processing circuit. In the SDP technique, the logic masking property of the soft error in the combinational circuit is utilized to mask the single-event upset (SEU) caused by disturbing particles in the inactive area. To further improve the performance, the masked portion of the datapath can be used as the estimation redundancy in the algorithmic soft-error-tolerance (ASET) technique. This technique is called subword-detection and redundant processing (SDRP). In the FGSET architecture, the soft error in each processing element (fine grain) can be recovered by the arithmetic datapath-level ASET technique. Analysis of the fast Fourier transform processor example shows that the proposed FGSET architecture can improve the performance of the coarse-grain SET (CGSET) by 8.5 dB. The low-cost SDP technique (1.03 ) yields a noise reduction of 5.3 dB over the CGSET approach (1.40 ), while the efficient SDRP I (1.57 ) and SDRP II (1.88 ) techniques outperform the CGSET approach by 24.5 and 30.5 dB, respectively.
Auteurs: Huang, Y.-H.;
Apparue dans: IEEE Transactions on Very Large Scale Integration Systems
Date publication: 02.-2010, volume: 18, issue:2, pages: 291 - 304
Editeur: IEEE
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» High-Performance Al–Sn–Zn–In–O Thin-Film Transistors: Impact of Passivation Layer on Device Stability
Résumé:
We fabricated high-performance thin-film transistors (TFTs) with an amorphous-Al–Sn–Zn–In–O (a-AT-ZIO) channel deposited by cosputtering using a dual Al–Zn–O and In–Sn–O target. The fabricated AT-ZIO TFTs, which feature a bottom-gate and bottom-contact configuration, exhibited a high field-effect mobility of 31.9 , an excellent subthreshold gate swing of 0.07 V/decade, and a high ratio of , even below the process temperature of 250 . In addition, we demonstrated that the temperature and bias-induced stability of the bottom-gate TFT structure can significantly be improved by adopting a suitable passivation layer of atomic-layer-deposition-derived thin film.
Auteurs: Yang, S.;Cho, D.-H.;Ryu, M. K.;Park, S.-H. K.;Hwang, C.-S.;Jang, J.;Jeong, J. K.;
Apparue dans: IEEE Electron Device Letters
Date publication: 02.-2010, volume: 31, issue:2, pages: 144 - 146
Editeur: IEEE
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» High-Performance Modulators and Switches for Silicon Photonic Networks-on-Chip
Résumé:
The stringent on- and off-chip communications demands of future-generation chip multiprocessors require innovative and potentially disruptive technology solutions, such as chip-scale photonic transmission systems. A space-switched, wavelength-parallel photonic network-on-chip has been shown to equip users with high-bandwidth, low-latency links in an energy-efficient manner. Here, experimental measurements on fabricated silicon photonic devices verify a large set of the components needed to construct these networks. The proposed system architecture is reviewed to motivate the demanding performance requirements of the components. Then, systems-level investigations are delineated for multiwavelength electrooptic modulators and photonic switching elements arranged in 1 2, 2 2, and 4 4 formations. Compact ( 10 m), high-speed (4 Gb/s) modulators, having a large degree of channel scalability (four channels demonstrated), are demonstrated with excellent data integrity (bit error ). Meanwhile, switches are shown to transfer extensive throughput bandwidths (250 Gb/s) with fast switching speeds (<1 ns) and sufficient extinction ratios (>10 dB). Data integrity is also verified for the switches ( ) with power penalty measurements amid dynamic operation. These network component demonstrations verify the feasibility of the proposed system architecture, while previous works have - verified its efficacy.
Auteurs: Lee, B. G.;Biberman, A.;Chan, J.;Bergman, K.;
Apparue dans: IEEE Journal of Selected Topics in Quantum Electronics
Date publication: 02.-2010, volume: 16, issue:1, pages: 6 - 22
Editeur: IEEE
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» High-performance surface-enhanced Raman scattering sensors based on Ag nanoparticles-coated Si nanowire arrays for quantitative detection of pesticides
Résumé:
A surface-enhanced Raman scattering (SERS) sensor made of Ag nanoparticles-coated Si nanowire (SiNW) arrays was fabricated for the quantitative detection of Carbaryl (an important nitrogen pesticide). H-terminated SiNWs were capable of reducing silver ions, leading to uniform deposition of silver nanoparticles on SiNW arrays. Such wire arrays exhibited a superior detection sensitivity of 10-17 M Rodamine 6G with high reproducibility. The sensor also enabled high sensitivity, reproducibility, and stability detection of Carbaryl. Significantly, the linear relation between the logarithmic concentrations and Raman peak intensities provided quantitative detection of Carbaryl.
Auteurs: Wang, X. T.;Shi, W. S.;She, G. W.;Mu, L. X.;Lee, S. T.;
Apparue dans: Applied Physics Letters
Date publication: 02.-2010, volume: 96, issue:5, pages: 053104 - 053104-3
Editeur: IEEE
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» High-performance W-band MMIC mixer module using GaAs metamorphic HEMT
Résumé:
In this letter, we report on a high-performance 94-GHz millimeter-wave monolithic integrated circuit (MMIC) mixer module using 0.1-[mu]m metamorphic high electron mobility transistors. A modified resistive mixer with a RF amplifier was proposed in this work for low conversion loss and high LO-RF isolation. The MMIC mixer module was fabricated using a MMIC chip and CPW-waveguide transitions. The fabricated mixer chip and module showed a low conversion loss of 6.3 and 9.5 dB, and LO-RF isolations of 24.8 and 30.4 dB at 94 GHz, respectively. This results are superior to those of previously W-band (75-110 GHz) MMIC mixers. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:815-817, 2010; DOI 10.1002/mop.25081
Auteurs: Dan An, Sung-Chan Kim, Jin-Koo Rhee
Apparue dans: Microwave and Optical Technology Letters
Date publication: 02.-2010
Editeur: Wiley InterScience
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» High-power broad-area InGaNAs/GaAs quantum-well lasers in the 1200nm range
Résumé:
High-power broad-area InGaNAs/GaAs quantum-well (QW) edge-emitting lasers on GaAs substrates in the 1200nm range are reported. The epitaxial layers of the InGaNAs/GaAs QW laser wafers were grown on n+-GaAs substrates by using metal-organic chemical vapor deposition (MOCVD). The thickness of the InGaNAs/GaAs QW layers is 70Å/1200Å. The indium content (x) of the InxGa1-xNyAs1-y QW layers is estimated to be 0.35-0.36, while the nitrogen content (y) is estimated to be 0.006-0.009. More indium content (In) and nitrogen content (N) in the InGaNAs QW layer enables the laser emission up to 1300nm range. The epitaxial layer quality, however, is limited by the...
Auteurs: Hung-Pin D., Yang , Chih-Tsung, Shih , Su-Mei, Yang , Tsin-Dong, Lee
Apparue dans: Microelectronics Reliability
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» High-Power Integrated Stimulator Output Stages With Floating Discharge Over a Wide Voltage Range for Nerve Stimulation
Résumé:
Two integrated nerve stimulator circuits are described. Both generate passively charge-balanced biphasic stimulating pulses of 1 to 16 mA with 10- s to 1-ms widths from 6- to 24-V supplies for implanted book electrodes. In both circuits, the electrodes are floating during the passive discharge anywhere within the range of the power rails, which may be up to 24 V. The first circuit is used for stimulation only. It uses a floating depletion transistor to enable continuous discharge of the electrodes, except when stimulating, without using power. The second circuit also allows neural signals to be recorded from the same tripole. It uses a modified floating complementary metal–oxide semiconductor (CMOS) discharge switch capable of operating over a range beyond the gate-to-source voltage limits of its transistors. It remains off for long periods using no power while recording. A 0.6- m silicon-on-insulator CMOS technology has been used. The measured performance of the circuits has been verified using multiple tripoles in saline.
Auteurs: Langlois, P. J.;Demosthenous, A.;Pachnis, I.;Donaldson, N.;
Apparue dans: IEEE Transactions on Biomedical Circuits and Systems
Date publication: 02.-2010, volume: 4, issue:1, pages: 39 - 48
Editeur: IEEE
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» High-resolution harmonic retrieval using the full fourth-order cumulant
Résumé:
R., van Vossen , H.W.L., Naus , A.P.M., Zwamborn
Auteurs: Source: Signal Processing, In Press, Accepted Manuscript, Available online 1 February 2010
Apparue dans: Signal Processing
Date publication: 02.-2010
Editeur: Elsevier B.V.
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» High-Speed Transmission in Multimode Fibers
Résumé:
High-speed transmission in multimode fibers (MMF) is becoming attractive for the realization of high-capacity transmission systems at low cost. This paper discusses the theoretical background of MMF transmission and gives an overview on system characterization and existing standards. The authors review latest achievements in component development for highest-speed MMF systems and discuss the challenges on reach, speed, and capacity-extension techniques for next generations of MMF systems.
Auteurs: Freund, R. E.;Bunge, C.-A.;Ledentsov, N. N.;Molin, D.;Caspar, C.;
Apparue dans: Journal of Lightwave Technology
Date publication: 02.-2010, volume: 28, issue:4, pages: 569 - 586
Editeur: IEEE
Document complet vers site de l'éditeur
 
» High-Technology Entrepreneurship in Emerging Economies: Firm Informality and Contextualization of Resource-Based Theory
Résumé:
High-technology entrepreneurship in emerging economies takes place in a context very different from that of developed economies. In large measure, this difference is due to greater resource constraints and higher levels of firm informality in emerging economies. In this study, we examine formal versus informal young high-technology ventures, assessing the extent to which firm informality moderates the relationship between technology investments and firm performance in an emerging economy. We find that technology investments are positively related to firm performance. Yet, firm informality positively moderates the relationship between resources and firm performance. The effect of resources tends to be contingent on the level of firm informality in an emerging economy. Greater resource constraints and higher levels of firm informality not only represent critical factors in emerging economies, but also are essential for contextualizing resource-based theory.
Auteurs: Siqueira, A. O.;Bruton, G. D.;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 02.-2010, volume: 57, issue:1, pages: 39 - 50
Editeur: IEEE
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» High-Throughput Continuous Beam Steering Using Rotating Polarization Gratings
Résumé:
A new beam steering concept comprising independently rotating, inline polarization gratings (PGs) is experimentally demonstrated. The approach, which we term Risley gratings, achieves high steering throughput within a large field-of-regard (FOR) in a fashion similar to Risley prisms, composed of wedged prisms. However, because PGs are patterned in thin liquid crystal layers, they enable a system with far less thickness, weight, and beam walk-off. Furthermore, large apertures are feasible and wavelengths from visible to infrared can be chosen. Any direction within a solid angle defined by twice the diffraction angle of each PG can be addressed mechanically. Here we demonstrate a Risley grating system with a 62 FOR and 89%–92% transmittance at 1550-nm wavelength, using two PGs with 6- grating period.
Auteurs: Oh, C.;Kim, J.;Muth, J.;Serati, S.;Escuti, M. J.;
Apparue dans: IEEE Photonics Technology Letters
Date publication: 02.-2010, volume: 22, issue:4, pages: 200 - 202
Editeur: IEEE
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» High-wire act
Résumé:
This paper discusses how Energy Reliability Council of Texas (ERCOT) balances transmission flows for Texas-size savings using its dynamic thermal ratings application. Competition in a deregulated environment requires companies to take advantage of all their transmission resources to the fullest extent possible to maximize profits.
Auteurs: Kyeon Hur;Boddeti, M.;Sarma, N.D.R.;Dumas, J.;Adams, J.;Soon-Kin Chai;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2010, volume: 8, issue:1, pages: 37 - 45
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Highly Efficient Blue-Emitting Materials Based on 10-Naphthylanthracene Derivatives for OLEDs
Résumé:
A series of new blue-emitting materials: 2-(10-(naphthalen-2-yl)anthracen-9-yl)pyridine (1); 1-(10-(naphthalen-2-yl)anthracen-9-yl)isoquinoline (2); 9-(3-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-9H-carbazole (3); 9-(4-(10-(naphthalen-2-yl)anthracen-9-yl)phenyl)-9H-carbazole (4); 9-(4-(10-(naphthalen-1-yl)anthracen-9-yl)phenyl)-9H-carbazole (5); 9-(4'-(10-(naphthalen-2-yl)anthracen-9-yl)biphenyl-4-yl)-9H-carbazole (6); and 9-(4'-(10-(naphthalen-1-yl)anthracen-9-yl)biphenyl-4-yl)-9H-carbazole (7) were designed and synthesized via the Suzuki cross-coupling reaction. To explore the electroluminescent properties of these materials, multilayer OLEDs were fabricated in the following sequence: ITO /4,4'-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB) (50 nm) /blue-emitting materials (1 - 7) (30 nm) /4,7-diphenyl-1,10-phenanthroline (Bphen) (30 nm) /lithium quinolate (Liq) (2 nm) /Al (100 nm). Among those, a device using 6 as an emitter exhibited a high external quantum efficiency of 3.83% (3.20% at 20 mA/cm2) with CIE coordinates of (0.152, 0.114). In order to...
Auteurs: Jeong Keun, Park , Kum Hee, Lee , Sunwoo, Kang , Jin Yong, Lee , Jung Sun, Park , ...
Apparue dans: Organic Electronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
Document complet vers site de l'éditeur
 
» Highly efficient undoped deep-blue electroluminescent device based on a novel pyrene derivative
Résumé:
A novel pyrene derivative 1,6-bis(9,9-dimethylfluorenyl)pyrene (DFP) was synthesized and characterized by 1H NMR spectrum, high resolution mass spectrum and elemental analysis. DFP exhibits bright blue emission both in solution and in solid thin film. Theoretical calculations show that the material has a non-coplanar structure and a high HOMO energy level. The undoped device based on DFP shows a stable deep-blue emission at 456nm under different voltage (up to 10V). The 1931 CIE coordinates (x=0.15,y=0.12) of the device are very close to the National Television Standards Committee's (NTSC) blue standard. The device achieves a maximum external quantum efficiency of 4.3% (current...
Auteurs: Zhiqiang, Wang , Chen, Xu , Weizhou, Wang , Weijun, Fu , Lianbin, Niu , ...
Apparue dans: Solid-State Electronics
Date publication: 02.-2010
Editeur: Elsevier B.V.
Document complet vers site de l'éditeur
 
» Highly selective separation of DNA fragments using optically directed transport
Résumé:
We present a design that allows selective separation of biomolecules of a particular size without performing complete separation of the sample by size. By focusing a laser beam onto a photoelectrode in contact with an electrolyte medium, a highly localized and optically controlled photoelectrophoretic trap is created. Moving the light beam along the photoelectrode consequently moves the trap. We demonstrate that by manipulating the speed of the photoelectrophoretic trap biomolecules of a particular size can be selectively separated from the mixture. We achieve a qualitative agreement between our experimental results and numerical simulations.
Auteurs: Braiman, Avital;Rudakov, Fedor;Thundat, Thomas;
Apparue dans: Applied Physics Letters
Date publication: 02.-2010, volume: 96, issue:5, pages: 053701 - 053701-3
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Highly Spectrally Efficient DWDM Transmission at 7.0 b/s/Hz Using 8 65.1-Gb/s Coherent PDM-OFDM
Résumé:
In this paper, we discuss the realization of wavelength-division multiplexing (WDM) transmission at high spectral efficiency. For this experiment, coherent polarization-division multiplexing--orthogonal frequency-division multiplexing (PDM-OFDM) is used as a modulation format. PDM-OFDM uses training symbols for channel estimation. This makes OFDM easily scalable to higher level modulation formats as channel estimation is realized with training symbols that are independent of the constellation size. Furthermore, because of its well-defined spectrum OFDM requires only a small guard band between WDM channels. The dependence of the number of OFDM subcarriers is investigated with respect to the interchannel linear crosstalk. At a constant data rate the number of OFDM subcarriers is estimated to achieve lower linear crosstalk in order to achieve higher spectral efficiency. We then experimentally demonstrate dense WDM (DWDM) transmission with 7.0-b/s/Hz net spectral efficiency using 8 65.1-Gb/s coherent PDM-OFDM signals with 8-GHz WDM channel spacing utilizing 32-quadrature-amplitude-modulation subcarrier modulation. Successful transmission is achieved over 240 km standard single-mode fiber (SSMF) spans with hybrid erbium-doped fiber amplifiers/Raman amplification.
Auteurs: Takahashi, H.;Al Amin, A.;Jansen, S. L.;Morita, I.;Tanaka, H.;
Apparue dans: Journal of Lightwave Technology
Date publication: 02.-2010, volume: 28, issue:4, pages: 406 - 414
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Historical introduction to capacitor technology
Résumé:
Over the next several years, this magazine will publish a series of papers, hopefully one per issue, on the subject of capacitor technology. The intention is to cover all important areas of the technology in some detail, including film, ceramic, electrolytic, and double-layer capacitors. One of the authors (S. B.) will edit the series.
Auteurs: Ho, J.;Jow, T.R.;Boggs, S.;
Apparue dans: IEEE Electrical Insulation Magazine
Date publication: 02.-2010, volume: 26, issue:1, pages: 20 - 25
Editeur: IEEE
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» Hollow Cathode Effect in Cold Cathode Fluorescent Lamps: A Review
Résumé:
Various efforts within the cold cathode fluorescent lamp (CCFL) industry are underway to decrease costs and increase electrode performance. In order to understand the impact that the choice of gas mixtures and pressures, cathode shape and material might have on the lamp's operation requires a knowledge of the underlying principles governing the glow discharge. We present a review of the literature on the hollow cathode effect and glow discharges, which has particular relevance to the design of CCFL lamp electrodes used in liquid crystal displays. We show that industry-wide standard gas pressures and electrode designs cannot operate in the hollow cathode regime.
Auteurs: Alberts, I. L.;Barratt, D. S.;Ray, A. K.;
Apparue dans: Journal of Display Technology
Date publication: 02.-2010, volume: 6, issue:2, pages: 52 - 59
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Hollow-core resonator based on out-of-plane two-dimensional photonic band-gap crystal cladding at microwave frequencies
Résumé:
We report on the demonstration of a resonator based on electromagnetic field confinement in a hollow-core by implementing an out-of-plane two-dimensional (2D) photonic band-gap (PBG) crystal cladding. In contrast with in-plane 2D PBG crystal devices, the PBG crystal studied here is perpendicular to the propagation axis. A resonator was constructed with silica rods to prove the concept at frequencies around 30 GHz. We show that the technique has the potential to reach quality factors (Q) of 5×105.
Auteurs: Humbert, Georges;Le Floch, Jean-Michel;Mouneyrac, David;Ferachou, Denis;Aubourg, Michel;Tobar, Michael E.;Cros, Dominique;Blondy, Jean-Marc;
Apparue dans: Applied Physics Letters
Date publication: 02.-2010, volume: 96, issue:5, pages: 051108 - 051108-3
Editeur: IEEE
Document complet vers site de l'éditeur
 
» HOSM Observer for a Class of Non-Minimum Phase Causal Nonlinear MIMO Systems
Résumé:
A higher order sliding mode observer is proposed for asymptotic identification of the full state vector and the vector of unknown inputs for MIMO nonlinear causal systems with unstable internal dynamics. The problem is addressed via consistent application of exact higher order sliding mode differentiators in conjunction with the method of stable system center. A numerical example illustrates the performance of the proposed algorithm.
Auteurs: Shtessel, Y. B.;Baev, S.;Edwards, C.;Spurgeon, S.;
Apparue dans: IEEE Transactions on Automatic Control
Date publication: 02.-2010, volume: 55, issue:2, pages: 543 - 548
Editeur: IEEE
Document complet vers site de l'éditeur
 
» How Developers' Experience and Ability Influence Web Application Comprehension Tasks Supported by UML Stereotypes: A Series of Four Experiments
Résumé:
In recent years, several design notations have been proposed to model domain-specific applications or reference architectures. In particular, Conallen has proposed the UML Web Application Extension (WAE): a UML extension to model Web applications. The aim of our empirical investigation is to test whether the usage of the Conallen notation supports comprehension and maintenance activities with significant benefits, and whether such benefits depend on developers ability and experience. This paper reports and discusses the results of a series of four experiments performed in different locations and with subjects possessing different experience—namely, undergraduate students, graduate students, and research associates—and different ability levels. The experiments aim at comparing performances of subjects in comprehension tasks where they have the source code complemented either by standard UML diagrams or by diagrams stereotyped using the Conallen notation. Results indicate that, although, in general, it is not possible to observe any significant benefit associated with the usage of stereotyped diagrams, the availability of stereotypes reduces the gap between subjects with low skill or experience and highly skilled or experienced subjects. Results suggest that organizations employing developers with low experience can achieve a significant performance improvement by adopting stereotyped UML diagrams for Web applications.
Auteurs: Ricca, Filippo;Di Penta, Massimiliano;Torchiano, Marco;Tonella, Paolo;Ceccato, Mariano;
Apparue dans: IEEE Transactions on Software Engineering
Date publication: 02.-2010, volume: 36, issue:1, pages: 96 - 118
Editeur: IEEE
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» How do Latecomer Firms Capture Value From Disruptive Technologies? A Secondary Business-Model Innovation Perspective
Résumé:
To fill the research gap between extant theory of disruptive technology and latecomer firms’ business-model innovation practices in emerging economies, we explore the new latecomer advantage implied in the phenomena of overshooting and nonconsuming. Based on inductive theory building with a comparative case study, we find that latecomer firms, though disadvantaged in technological capabilities and market resources, can successfully introduce disruptive technologies from advanced economies into emerging economies through secondary business-model innovations. They provide cheaper, simpler, but good enough products or services that ordinary citizens in emerging economies can easily afford and access. How do latecomer firms capture value from disruptive technologies within the emerging economies context? While articulating an appropriate value proposition that is attractive for local customers is of great importance for those latecomer firms, they should also fully utilize strategic partners’ complementary assets to build a unique value network embedded within local infrastructure. Thus, those latecomer firms tactfully bypass the substantial first-mover advantages and global advantages of multinational incumbents, and leverage their latecomer advantages such as low price and local savvy. Thus, latecomer firms should not ignore those disruptive growth opportunities within the large population of mass customers and nonconsumers in emerging economies.
Auteurs: Wu, X.;Ma, R.;Shi, Y.;
Apparue dans: IEEE Transactions on Engineering Management
Date publication: 02.-2010, volume: 57, issue:1, pages: 51 - 62
Editeur: IEEE
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» How Internet Security Breaches Harm Market Value
Résumé:
Decision-tree induction is an effective technique for examining the factors influencing abnormal stock market returns when security breaches are announced in the public media. In this article, the authors extend a previous study, specifically identifying new relationships between abnormal returns and firm and attack characteristics and subject them to traditional statistical testing. They relate their results to the confidential, integrity, and availability dimensions of information security and discuss the findings' technical and managerial implications. The Web extra for this article presents detailed event data.
Auteurs: Andoh-Baidoo, Francis Kofi;Amoako-Gyampah, Kwasi;Osei-Bryson, Kweku-Muata;
Apparue dans: IEEE Security & Privacy
Date publication: 02.-2010, volume: 8, issue:1, pages: 36 - 42
Editeur: IEEE
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» How Internet Users' Privacy Concerns Have Evolved since 2002
Résumé:
In 2002, the authors established a baseline for Internet users' online privacy values, finding information transfer, notice/awareness, and information storage were the top online privacy concerns. Since this survey, many privacy-related events have occurred, including changes in online trends and the creation of laws, prompting the authors to rerun the survey in 2008 to examine how these events might have affected users' online privacy concerns. In this article, they discuss the 2008 survey, which revealed that US Internet users' top three privacy concerns didn't change over the course of six years, although their level of concern did. The authors also examine differences in privacy concerns between US and international respondents. The Web extra groups the survey statements according to six dimensions of privacy concerns based on the following classifications—personalization, notice/awareness, information transfer, information collection, information storage, and access/participation.
Auteurs: Antón, Annie I.;Earp, Julia B.;Young, Jessica D.;
Apparue dans: IEEE Security & Privacy
Date publication: 02.-2010, volume: 8, issue:1, pages: 21 - 27
Editeur: IEEE
Document complet vers site de l'éditeur
 
» How many surface plasmons are locally excited on the ridges of metallic lamellar gratings?
Résumé:
In contrast to earlier classical studies that analyze the surface Bloch modes supported by metallic gratings composed of slits as collective surface-plasmon-polaritons (SPPs) resonances (or poles) of the entire periodic problem, we study the normalized rate of SPPs that are locally launched on every individual ridge of metallic lamellar gratings. With this “microscopic” description at the unit-cell level, we further explain how these individual SPPs constructively interfere to build up the classical collective resonances. The approach, which combines analytical treatments and fully-vectorial computations, shines new light on an important and classical phenomenon of grating diffraction.
Auteurs: Wang, B.;Lalanne, P.;
Apparue dans: Applied Physics Letters
Date publication: 02.-2010, volume: 96, issue:5, pages: 051115 - 051115-3
Editeur: IEEE
Document complet vers site de l'éditeur
 
» How Pair Programming Really Works
Résumé:
Pair programming has generated considerable controversy: some developers are enthusiastic about it, almost evangelical; others are dubious, even hostile. However, a large factor in this controversy is that programmers label a wide variety of practices under the "pair programming" umbrella. Thus, before our community can sensibly discuss how pair programming works, we first need to establish exactly what it is.
Auteurs: Wray, S.;
Apparue dans: IEEE Software
Date publication: 02.-2010, volume: 27, issue:1, pages: 50 - 55
Editeur: IEEE
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» Howard Street Tunnel [History]
Résumé:
The paper gives an overview on the historical development of electric railway transportation in the United States. It focuses on the construction of the Howard street tunnel in Baltimore, Maryland that spans 2.3 kilometers.
Auteurs: Cunningham, J.J.;
Apparue dans: IEEE Power and Energy Magazine
Date publication: 02.-2010, volume: 8, issue:1, pages: 62, 64 - 71
Editeur: IEEE
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» Huber-based unscented filtering and its application to vision-based relative navigation
Résumé:
A new algorithm called Huber-based unscented filtering (UF) is derived and applied to estimate the precise relative position, velocity and attitude of two unmanned aerial vehicles in the formation flight. The relative states are estimated using line-of-sight measurements between the vehicles along with acceleration and angular rate measurements of the follower. By making use of the Huber technique to modify the measurement update equations of standard UF, the new filtering could exhibit robustness with respect to deviations from the commonly assumed Gaussian error probability, for which the standard unscented filtering would exhibit severe degradation in estimation accuracy. Furthermore, contrast to standard extended Kalman filtering, more accurate estimation and faster convergence could be achieved from inaccurate initial conditions. During filter design, the global attitude parameterisation is given by a quaternion, whereas a generalised three-dimensional attitude representation is used to define the local attitude error. A multiplicative quaternion-error approach is used to guarantee that quaternion normalisation is maintained in the filter. Simulation results are shown to compare the performance of the new filter with standard UF and standard extended Kalman filtering for non-Gaussian case.
Auteurs: Wang, X.;Cui, N.;Guo, J.;
Apparue dans: IET Radar, Sonar & Navigation
Date publication: 02.-2010, volume: 4, issue:1, pages: 134 - 141
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Human-robot communication for collaborative decision making -- A probabilistic approach
Résumé:
Humans and robots need to exchange information if the objective is to achieve a task collaboratively. Two questions are considered in this paper: what and when to communicate. To answer these questions, we developed a human-robot communication framework which makes use of common probabilistic robotics representations. The data stored in the representation determines what to communicate, and probabilistic inference mechanisms determine when to communicate. One application domain of the framework is collaborative human-robot decision making: robots use decision theory to select actions based on perceptual information gathered from their sensors and human operators. In this paper, operators are regarded as...
Auteurs: Tobias, Kaupp , Alexei, Makarenko , Hugh, Durrant-Whyte
Apparue dans: Robotics and Autonomous Systems
Date publication: 02.-2010
Editeur: Elsevier B.V.
Document complet vers site de l'éditeur
 
» Hunting Down the Bubble Makers in Fabs
Résumé:
Based on a simulated Non Volatile Memory fab, we employ data-mining to identify and quantify the apparent causes of work in process bubbles along the process. The chosen bubble formalization methods proved able to detect the phenomenon and enabled its occurrence frequency to be forecasted. In the chosen environment, bubbles seem to be highly correlated with the utilization patterns of the process segment considered.
Auteurs: Hassoun, M.;Rabinowitz, G.;
Apparue dans: IEEE Transactions on Semiconductor Manufacturing
Date publication: 02.-2010, volume: 23, issue:1, pages: 13 - 20
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Hybrid connection of RF MEMS and SMT components in an impedance tuner
Résumé:
This paper presents a systematic construction of a model for a hybrid connected RF MEMS and SMT components in a reconfigurable impedance tuner. The double stub hybrid impedance tuner which employs a high number of MEMS switches is selected to demonstrate the feasibility of the connections. In the hybrid tuner, MEMS switches are actuated with DC bias signals, where SMT resistors de-couple RF from the DC lines. The hybrid tuner is realized in two steps, where the MEMS impedance tuner is fabricated on a glass substrate using an in-house surface micromachining process, and the SMT resistors are mounted on the...
Auteurs: Mehmet, Unlu , Kagan, Topalli , Halil, Ibrahim Atasoy , Simsek, Demir , Ozlem, Aydin Civi , ...
Apparue dans: AEU - International Journal of Electronics and Communications
Date publication: 02.-2010
Editeur: Elsevier B.V.
Document complet vers site de l'éditeur
 
» Hybrid System for Simultaneous Fluorescence and X-Ray Computed Tomography
Résumé:
A hybrid imaging system for simultaneous fluorescence tomography and X-ray computed tomography (XCT) of small animals has been developed and presented. The system capitalizes on the imaging power of a 360 -projection free-space fluorescence tomography system, implemented within a microcomputed tomography scanner. Image acquisition is based on techniques that automatically adjust a series of imaging parameters to offer a high dynamic range dataset. Image segmentation further allows the incorporation of structural priors in the optical reconstruction problem to improve the imaging performance. The functional system characteristics are showcased, and images from a brain imaging study are shown, which are reconstructed using XCT-derived priors into the optical forward problem.
Auteurs: Schulz, R. B.;Ale, A.;Sarantopoulos, A.;Freyer, M.;Soehngen, E.;Zientkowska, M.;Ntziachristos, V.;
Apparue dans: IEEE Transactions on Medical Imaging
Date publication: 02.-2010, volume: 29, issue:2, pages: 465 - 473
Editeur: IEEE
Document complet vers site de l'éditeur
 
» Hydrodynamics of a dual fluidized bed gasifier
Résumé:
The hydrodynamics of a circulating fluidized bed gasification system with dual fluidized bed concept has been studied through a cold model investigation. The article focuses on the axial voidage, the pressure drops across various components and the solid circulation under different operating conditions. The control of solids circulation between the dual fluidized beds has been done through an L-valve system. A mathematical model of hydrodynamic behavior of the system has been presented. It is observed from the investigated operating parameters that the aeration flow, the secondary air flow and particle diameter have the strongest influence on system pressure drop and...
Auteurs: M.K., Karmakar , A.B., Datta
Apparue dans: Advanced Powder Technology
Date publication: 02.-2010
Editeur: Elsevier B.V.
Document complet vers site de l'éditeur
 
» Hydrogen and inert species in solid phase epitaxy
Résumé:
The incorporation of hydrogen during deposition of amorphous germanium can influence solid phase epitaxy in many ways. We show that Ge–H bonds are not important during the crystallization process. However, atomic hydrogen is important during deposition to obtain a highly disordered layer. We have found that highly disordered layers can also be obtained when using a beam of inert gas species during ultrahigh vacuum deposition. These inert species effectively increase the disorder of the layer by limiting the surface mobility of adsorbed germanium atoms. In this way subsequent solid phase epitaxy can be improved significantly.
Auteurs: Lieten, R. R.;Degroote, S.;Clemente, F.;Leys, M.;Borghs, G.;
Apparue dans: Applied Physics Letters
Date publication: 02.-2010, volume: 96, issue:5, pages: 052109 - 052109-3
Editeur: IEEE
Document complet vers site de l'éditeur
 


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