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2005 International Semiconductor Device Research Symposium

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

ISBN: (纸本)1424400848

With the rapid development of high-power white light-emitting diodes (LEDs), advances in packaging are required to further improve the device performance. In this work, an optimized packaging configuration for high power LED lamps with enhanced phosphorescence efficiency is presented based on ray-tracing simulations and experimental results. Figure 1 shows two phosphor arrangements, namely a "proximate phosphor" and a "remote phosphor" arrangement. The surface of the reflector cup is assumed to be either specular or diffuse. Three different encapsulant geometries, i.e., a "flat" (no cap), "convex" (spherical cap with height h = r/2), and "hemispherical" (h = r) top surface, are used in the simulations. Figure 2 shows phosphorescence efficiency with different packaging configurations obtained by ray-tracing simulation. The packaging configuration with remote phosphor, diffuse reflector cup and hemispherical encapsulation shows a 50% enhancement of phosphorescence efficiency compared to conventional packaging configuration. This improvement is attributed to reduced absorption of the phosphorescence by the LED chip and the reduction of deterministic optical modes trapped inside the encapsulant of remote-phosphor and diffuse reflector cup configuration. The angular dependence of the reflectivity for a diffuse Ag reflector and a specular Ag reflector is measured and shown in Figure 3. The roughened Ag reflector has a more than two orders of magnitude higher diffusely reflected power compared with the specular Ag reflector, which leads to the extraction of the trapped optical modes occurring in packaging structures with specular reflector cups. Dichromatic LED lamps comprising an ultraviolet GaN LED (λ = 400 nm) with a blue phosphor and a blue GaInN LED (λ = 470 nm) with a yellow phosphor are fabricated with different phosphor arrangements and reflector cups. The emission spectra of the reference primary LED emitters and of the dichromatic lamps operating at 20 mA are mea

关键词： Chip scale packages

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Online traffic light control through gradient estimation using stochastic fluid models

Online traffic light control through gradient estimation usi...

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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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Deadline spanning: a graph based approach

Deadline spanning: a graph based approach

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IEEE International Conference on Embedded and Real-Time Computing systems and Applications (RTCSA)

作者： S.M. Petters School for Computer Science and Engineering University of New South Wales Sydney Australia Embedded Real-Time Operating Systems Program NICTA Sydney Australia

Microkernel based systems tend to depend heavily on IPC. This paper addresses the problem of a system response spanning more than one task in an embedded real-time system. The approach is based on a mix of classical response time analysis equations and a graph based approach to estimate the impact of different parts of the system on the time needed by the system to respond. This approach has the major advantage of being intuitive.

关键词： Delay Real time systems Yarn Kernel Operating systems computer science Differential equations Embedded system Australia Council Control systems

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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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Appointments for 2005-2006 term

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IEEE Transactions on Very Large Scale Integration (VLSI) systems 2005年第7期13卷 773-782页

作者： Ranganathan, Nagarajan Agrawal, Vishwani D. Chakradhar, Srimat T. Chakrabarty, Krishnendu Courtois, Bernard DeMara, Ronald Hu, Xiaobo Sharon Ismail, Yehea I. Jha, Niraj K. John, Lizy Kurian Ker, Ming-Dou Koren, Israel Liu, Bin-Da Marculescu, Diana Marculescu, Radu Narayanan, Vijaykrishnan Nassif, Sani R. Nowick, Steven M. Sapatnekar, Sachin S. Sherlekar, Sunil Sylvester, Dennis Vemuri, Ranga Pham, Michael Department of Computer Science and Engineering University of South Florida Tampa FL 33620 United States Department of Computer Science and Engineering Nanomaterials and Nanomanufacturing Research Center University of South Florida Tampa United States IEEE United States Systems United States Department of Electrical and Computer Engineering Rutgers University New Brunswick NJ United States IETE India ACM NEC Laboratories America Inc. Princeton NJ United States Duke University Durham NC United States ACM SIGDA Sigma Xi United States Laboratory of Techniques of Informatics and Microelectronics for Computer Architectecture ASME IMAPS IEEE Computer Society University of Central Florida Orlando United States Computer Engineering Program SEECS Department of Computer Science and Engineering University of Notre Dame Notre Dame IN United States Northwestern University Evanston IL United States Department of Electrical Engineering Princeton University Princeton NJ United States Association for Computing Machinery Austin United States UT Austin Engineering Foundation United States Department of Electronics Engineering National Chiao-Tung University Taiwan Department of Electrical and Computer Engineering University of Massachusetts Amherst United States Department of Electrical Engineering Department of Electrical and Computer Engineering Carnegie Mellon University Pittsburgh PA United States Electrical and Computer Engineering Faculty Carnegie Mellon University Pittsburgh PA United States Computer Science and Engineering Department Pennsylvania State University University Park United States IBM Austin Research Laboratory Austin TX United States Columbia University New York NY United States Department of Electrical and Computer Engineering University of Minnesota Minneapolis United States Tata Consultancy Services Centre of Excellence for Embedded Systems India Department of Electrical Engineering IIT Bombay India Department of Electrical Engineering Uni

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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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Scientific models management in computational grids

Scientific models management in computational grids

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17th International Conference Scientific and Statistical Database Management, SSDBM 2005

作者： De Brito, Halisson Matos Strauch, Julia De Souza, Jano Moreira Osthoff, Carla COPPE/UFRJ Systems Engineering and Computer Science Program Federal University of Rio de Janeiro PO Box 68511 ZIP Code: 21945-970 Rio de Janeiro RJ Brazil ENCE /IBGE National School of Statistical Sciences 106 S. 401 ZIP Code: 20231-050 R. André Cavalcanti Rio de Janeiro RJ Brazil LNCC National Laboratory for Scientific Computing Av. Getulio 333 Quitandinha Vargas Petrópolis RJ Brazil IM/UFRJ Institute of Mathematics Federal University of Rio de Janeiro PO Box 68511 ZIP Code: 21945-970 Rio de Janeiro RJ Brazil

This paper presents MODENA, an architecture for scientific models management using Computational Grid platform. This architecture is comprised of two systems: ModManager and ModRunner. ModManager deals with knowledge management about scientific models, acting as a scientific models library allowing for cataloguing, searching, reutilization and generation of new models. To achieve this, a metamodel is proposed to classify models, in order to support the organization, searching and retrieving of models. ModRunner manages the execution of models in a Grid environment allowing for model composition to generate a scientific Grid Workflow to be executed by distributed services offered by Grid Services. An initial prototype of ModManager is presented.

关键词： Knowledge management

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New class of the FPGA efficient cryptographic primitives

New class of the FPGA efficient cryptographic primitives

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IEEE International Symposium on Circuits and systems (ISCAS)

作者： N.A. Moldovyan M.A. Eremeev N. Sklavos O. Koufopavlou Specialized Center of Program Systems SPECTR Saint Petersburg Russia Electrical & Computer Engineering Department University of Patras Patras Greece

This work focuses the problem of further development of the approach to the fast cipher design, based on data-dependent (DD) permutations (DDP). A new class of the DDP-like operations is described. New DD operations (DDO) are constructed replacing the switching element in the DDP boxes by different controlled elements (CE) having the same size. Full classification of CE with two non-linear outputs is presented. Two subclasses of nonlinear CE, with the best differential characteristics are recommended for the use in the non-linear DDO-boxes synthesis. The non-linear CE boxes are implemented in FPGA modules using the same hardware resources as switching elements. It is shown that the use of the nonlinear DDO, instead of DDP allows one to reduce the number of rounds. With this technique higher Performance/Cost ratio is achieved, while designing fast hardware suitable ciphers.

关键词： Field programmable gate arrays Cryptography Hardware Data security Size control Data engineering Design engineering Costs Design optimization Boolean functions

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Minimum size primitives for efficient VLSI implementation of DDO-based ciphers

Minimum size primitives for efficient VLSI implementation of...

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Mediterranean Electrotechnical Conference (MELECON)

作者： A.A. Moldovyan N.A. Moldovyan N. Sklavos Specialized Center of Program Systems SPECTR Saint Petersburg Russia Electrical & Computer Engineering Department University of Patras Patras Greece

This work focuses the problem of increasing the performance of the ciphers based on data-dependent (DD) operations (DDO) for VLSI implementations. New minimum size primitives are proposed to design DDOs. Using advanced DDOs instead of DD permutations (DDP) in the DDP-based iterative ciphers Cobra-H64 and Cobra H128 the number of rounds has been significantly reduced yielding enhancement of the "performance per cost" value. To obtain further enhancement of this parameter a new crypto-scheme based on the advanced DDOs is proposed. The FPGA implementation of the proposed crypto-scheme achieves higher throughput value and minimizes the allocated resources than the conventional designs.

关键词： Very large scale integration Cryptography Field programmable gate arrays Communication system security Information security Hardware Data security Data engineering Throughput Resource management

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