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作者： Panayiotou, Christos G. Howell, William C. Fu, Michael Department of Electrical and Computer Engineering University of Cyprus Nicosia Cyprus Applied Mathematics Scientific Computation Program Department of Mathematics University of Maryland College Park MD 20742 United States Smith School of Business and Institute for Systems Research University of Maryland College Park MD 20742 United States

ISBN: (纸本)008045108X

in this paper, we consider the problem of dynamically regulating the timing of traffic light controllers in busy cities. We use a Stochastic Fluid Model (SFM) to model the dynamics of the queues formed at an intersection. Based on this model, we derive gradients of the queue lengths with respect to the green/red light lengths within a signal cycle. We report preliminary numerical results comparing the performance of the estimates with finite-difference and smoothed perturbation analysis estimates. Then all estimators are used to optimize the traffic system via Stochastic Approximation. Copyright © 2005 IFAC.

关键词： Stochastic systems

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Transistor characteristics of thermal chemical vapor deposition carbon nanotubes field emission triode

Journal of Vacuum Science & Technology B: Microelectronics a...

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Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena 2005年第2期23卷 868-873页

作者： Y. M. Wong W. P. Kang J. L. Davidson W. Hofmeister S. Wei J. H. Huang Department of Electrical Engineering and Computer Science Vanderbilt University Nashville Tennessee 37235 Interdisciplinary Graduate Program in Material Science Vanderbilt University Nashville Tennessee 37235 Department of Materials Science and Engineering National Tsing Hua University Hsinchu 300 Taiwan Republic of China

A study of thermal chemical vapor deposition (CVD) grown carbon nanotubes (CNTs) field emitters in a triode amplifier configuration is reported. The CNT transistor characteristics were examined by integrating gate and anode with CNT cathode in two structural forms, utilizing a TEM grid (transmission electron microscope specimen holder) as the gate electrode and a micropatterned CNT with self-aligned gate. The TEM-grid CNT triode displayed clearly gate-controlled current modulation behavior with distinct cutoff, linear, and saturation regions, and a reasonable gate turn-on field of ∼5.4V∕μm despite a large cathode-gate spacing of ∼120μm . The field emission result established the basic transistor characteristics of CNTs in a triode configuration. A CNT triode construct with a self-aligned gated fabrication technique was also developed to realize a monolithic triode structure with shorter gate-cathode spacing, lowering gate voltage, and enhancing emission current. The triode exhibited a significantly lower gate turn-on voltage of ∼40V , and gate-controlled modulation of the emission current. An anode current density of ∼30mA∕cm2 was achieved at a gate voltage of ∼80V and an anode voltage of ∼200V . The dc characteristics for both of the CNT triodes were investigated, including Ia versus Va for different Vg . Moreover, dc parameters such as transconductance, amplification factors, and anode resistance of the triode amplifier were determined. The CNT triodes exhibited useful amplification factor and high output impedance.

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Wireless hearing aid system simulations using advanced design system™: A behavioral modeling approach

Wireless hearing aid system simulations using advanced desig...

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2005 27th Annual International Conference of the engineering in Medicine and Biology Society, IEEE-EMBS 2005

作者： Rana, Ram Singh Tang, Bin Zhang, Liang Krishna, Garg Hari Wang, Yun Institute of Microelectronics Singapore Science Park II 11 Science Park Road Singapore 117685 Singapore Graduate Program in Bioengineering National University of Singapore Singapore 117597 Singapore Department of Electrical and Computer Engineering National University of Singapore Singapore 119260 Singapore Department of Otolaryngology Faculty of Medicine National University of Singapore Singapore 119074 Singapore

ISBN: (纸本)0780387406

The stringent requirements on size and power consumption constrain the conventional hearing aid devices from providing the patients an economic and user friendly solution, specifically for better noise cancellation. With the advancements in technologies such as integrated circuits design, wireless communications and digital signal processing techniques, the wireless hearing aids having multi-microphones, analog, digital and mixed signals and radio frequency signals processing circuits, DSP and programmable units seem to be promising to provide enhanced performance. The focus of this paper is about the system simulation of a typical wireless hearing aid using Agilent Advanced Design System™. The behavioral modeling features are exploited to enable the whole system simulations including electro-acoustic transducers. A few system level simulation results are included. © 2005 IEEE.

关键词： Hearing aids

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Wireless Hearing Aids System Simulation

Wireless Hearing Aids System Simulation

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Asilomar Conference on Signals, Systems & computers

作者： H.K. Garg Tang Bin Zhang Liang R.S. Rana Department of Electrical & Computer Engineering National University of Singapore Singapore 11 Science Park Road Institute of Microelectronics Singapore Graduate Program in Bioengineering National University of Singapore Singapore

Although wireless hearing aid systems have been proposed by several research groups, no viable whole-system simulation results have been reported so far for better evaluation of this advanced hearing device. In this paper, a system-level simulation using ADStrade is presented based on one of the typical wireless hearing aid architecture. The results show that the wireless hearing aid system function can be simulated and verified. And from these results, we can get a very promising performance which can be used for further design

关键词： Hearing aids Auditory system Circuit simulation Radio frequency Noise cancellation Mathematical model Costs RF signals Signal processing Computational modeling

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A Formal Approach for Component Based Embedded Software Modelling and Analysis

A Formal Approach for Component Based Embedded Software Mode...

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IEEE International Symposium on Industrial Electronics (ISIE)

作者： H.O. Almeida L. Dias da Silva E. Oliveira A. Perkusich Department of Electrical Engineering Federal University of Campina Grande Campina Grande Paraiba Brazil Graduate Program in Computer Science Federal University of Campina Grande Campina Grande Paraiba Brazil

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Vertically aligned carbon nanotubes field emission devices fabricated by furnace thermal CVD at atmospheric pressure

Vertically aligned carbon nanotubes field emission devices f...

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International Conference on Vacuum Nanoelectronics (IVNC)

作者： S. Wei W.P. Kang J.L. Davidson W.H. Hofmeister B.K. Choi J.H. Huang Program in Materials Science Vanderbilt University Nashville TN USA Department of Electrical Engineering and Computer Science Vanderbilt University Nashville TN USA Department of Materials Science and Engineering National Tsing Hua University Hsinchu Taiwan

In this paper, vertically aligned carbon nanotubes field emission devices were fabricated from the as grown carbon nanotubes (CNTs) by furnace thermal CVD at atmospheric pressure. The device was tested in vacuum (/spl sim/10/sup -6/ torr) for field emission characterization. The turn-on field was about 3 V//spl mu/m, which is comparable to data reported elsewhere.

关键词： Carbon nanotubes Furnaces Temperature Raman scattering Chemical vapor deposition Cathodes Diodes Morphology Scanning electron microscopy Spectroscopy

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Enhancement of light extraction GaN light-emitting diodes by omni-directional reflectors with ITO nanorod low-refractive-index layer

Enhancement of light extraction GaN light-emitting diodes by...

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Fifth International Conference on Solid State Lighting

作者： Kim, Jong Kyu Xi, J.-Q. Luo, Hong Cho, Jaehee Sone, Cheolsoo Park, Yongjo Fred Schubert, E. Electrical Computer and Systems Engineering Dept. Rensselaer Polytechnic Institute 110 Eighth Street Troy NY 12180 United States Dept. of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute 110 Eighth Street Troy NY 12180 United States Photonics Program Team Samsung Advanced Institute of Technology Suwon 440-600 Korea Republic of

Enhancement of light extraction in GaN light-emitting diodes (LEDs) employing omnidirectional reflectors (ODRs) is presented. The ODR consists of GaN, ITO nanorod low-refractive-index layer, and an Ag layer. An array of ITO nanorods is deposited by oblique-angle deposition using e-beam evaporation. The refractive index of the ITO nanorods is 1.34 at 461 nm, significantly lower that that of dense ITO, which is n = 2.06 at 461 nm. It is experimentally shown that the GaN LED with GaN/ITO nanorods/Ag ODR show much better electrical properties and higher light-extraction efficiency than LEDs with Ag contact. This is attributed to enhanced reflectivity of the ODR by using an ITO low-refractive-index layer with high transparency, high conductivity, and low refractive index.

关键词： Light emitting diodes

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ONLINE TRAFFIC LIGHT CONTROL THROUGH GRADIENT ESTIMATION USING STOCHASTIC FLUID MODELS

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IFAC Proceedings Volumes 2005年第1期38卷 90-95页

作者： Christos G. Panayiotou William C. Howell Michael Fu Department of Electrical and Computer Engineering University of Cyprus Nicosia Cyprus Department of Mathematics Applied Mathematics Scientific Computation Program University of Maryland College Park MD 20742 USA Smith School of Business and Institute for Systems Research University of Maryland College Park MD 20742 USA

In this paper, we consider the problem of dynamically regulating the timing of traffic light controllers in busy cities. We use a Stochastic Fluid Model (SFM) to model the dynamics of the queues formed at an intersection. Based on this model, we derive gradients of the queue lengths with respect to the green/red light lengths within a signal cycle. We report preliminary numerical results comparing the performance of the estimates with finite-difference and smoothed perturbation analysis estimates. Then all estimators are used to optimize the traffic system via Stochastic Approximation.

关键词： Traffic control perturbation analysis stochastic approximation

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Effects of deposition and synthesis parameters on size, density, structure, and field emission properties of Pd-catalyzed carbon nanotubes synthesized by thermal chemical vapor deposition

Journal of Vacuum Science & Technology B: Microelectronics a...

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Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena 2005年第2期23卷 793-799页

作者： S. Wei W. P. Kang W. H. Hofmeister J. L. Davidson Y. M. Wong J. H. Huang Interdisciplinary Program in Materials Science Vanderbilt University Nashville Tennessee 37235 USA Department of Electrical and Computer Engineering Vanderbilt University Box 1661-B Vu Station B Nashville Tennessee 37235 USA Department of Chemical Engineering Vanderbilt University Nashville Tennessee 37235 USA Department of Materials Science and Engineering National Tsing Hua University Hsinchu 300 Taiwan Republic of China

The effects of deposition parameters and NH3 pretreatment on the size and distribution of Pd catalytic particles and subsequently their effects on the characteristics of the synthesized carbon nanotubes (CNTs) were systematically investigated. It was found that the size of Pd particles decreases and the particle density (total number of Pd particles per unit area) increases as the Pd film thickness decreases. Moreover, pretreatment of Pd film in NH3 gas promotes smaller Pd particles and higher particle density which is beneficial for CNT growth. The CNTs were synthesized by thermal chemical vapor deposition at 750 °C using methane (CH4) as the carbon source, and a mixture of Ar/H2 (80 vol %: 20 vol %) as a carrier gas with NH3 serving as a processing reagent. The incorporation of NH3 in CNT synthesis, per the specific pretreatment of catalytic film, has a distinct effect on the size and morphology of CNTs produced. The interrelation between processing, structure and emission behavior of CNTs produced with different synthesis conditions was examined by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and field emission measurements.

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Journal of Information Science and engineering: Editorial notice

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Journal of Information Science and engineering 2005年第5期21卷 i-ii页

作者： Lee, Der-Tsai Amato, Nancy M. Chang, Shih-Fu Chen, Homer H. Chen, Tsuhan Hsu, Tsan-Sheng Hwang, Jenq-Neng Kuo, Sy-Yen Kuo, Tei-Wei Li, Chung-Sheng Tokuyama, Takeshi Wing, Jeannette Wu, Tzong-Chen Yen, John Computer Science at Texas A and M University United States Parasol Laboratory United States IEEE Transactions on Parallel and Distributed Systems Computing Research Association's Committee on the Status of Women in Computing Research CRA-W's Distributed Mentor Program United States Department of Electrical Engineering Columbia University United States Lab. United States College of Electrical Engineering and Computer Science National Taiwan University Taiwan IEEE Transactions on Circuits and Systems for Video Technology IEEE Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA United States ACM ACM SIGACT IEEE Computer Society IICM Austria Research and Development of the Department Multimedia Signal Processing Technical Committee IEEE Signal Processing Society United States IEEE Transactions on Circuits and systems for Video Technology College of Electrical Engineering and Computer Science National Taiwan Ocean University Keelung Taiwan Department of Electrical Engineering National Taiwan University Taiwan Department of Computer Science and Information Engineering National Taiwan University Taipei Taiwan IEEE Technical Committee on Real-Time Systems Computer Science Division IBM T.J. Watson Research Center United States IBM Research Division Graduate School of Information Sciences Tohoku University Japan ACM IPSJ Mathematical Society of Japan Japan Department of Computer Science Computer Science Department Carnegie Mellon University United States National Academies of Science's Computer Science and Telecommunications Board United States Microsoft's Trustworthy Academic Advisory Board Intel Research Pittsburgh's Advisory Board United States Dartmouth's Institute for Security Technology Studies Advisory Committee Canada Sloan Research Fellowships Program Committee United States ACM Taiwan China Information Sciences and Technology Pennsylvania State University United States Laboratory for Intelligent Agents Penn State's School of Info

No abstract available

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