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2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05

作者： Lima, A. Zen, H. Nankaku, Y. Tokuda, K. Kitamura, T. Resende, F.G. Nagoya Institute of Technology Department of Computer Science and Engineering Nagoya 466-8555 Japan Federal University of Rio de Janeiro Dept. of Electronics and Computer Engineering/EPoli Program of Electrical Engineering/COPPE Rio de Janeiro 21945-970 Brazil

ISBN: (纸本)0780388747

This paper presents an analysis of the applicability of Sparse Kernel Principal Component Analysis (SKPCA) for feature extraction in speech recognition, as well as, a proposed approach to make the SKPCA technique realizable for a large amount of training data, which is an usual context in speech recognition systems. Although the KPCA (Kernel Principal Component Analysis) has proved to be an efficient technique for being applied to speech recognition, it has the disadvantage of requiring training data reduction, when its amount is excessively large. The standard approach to perform this data reduction is to randomly choose frames from the original data set, which does not necessarily provide a good statistical representation of the original data set. In order to solve this problem a likelihood related re-estimation procedure was applied to the KPCA framework, thus creating the SKPCA. The experimental results show the efficiency of SKPCA technique with the proposed approach over the KPCA with the standard sparse solution using randomly chosen frames and the standard feature extraction techniques. © 2005 IEEE.

关键词： Speech recognition

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The bias of the MVDR beamformer outputs under diagonal loading

The bias of the MVDR beamformer outputs under diagonal loadi...

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2005 IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP '05

作者： Nadakuditi, Raj Rao Edelman, Alan Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science MIT/WHOI Joint Program Cambridge MA 02139 United States Massachusetts Institute of Technology Department of Mathematics Cambridge MA 02139 United States

ISBN: (纸本)0780388747

The MVDR beamformer is the most extensively used array processing algorithm and involves inverting the sample covariance matrix. In the snapshot deficient scenario, when the number of sensors is greater than or approximately equal to the number of snapshots, the eigenvalues of the resulting sample covariance matrix are poorly conditioned. Diagonal loading is then applied to the sample covariance matrix. Expressions for the bias of the resulting MVDR beamformer outputs in the sidelobe region are presented that are exact for asymptotically large arrays. Numerical simulations confirm the accuracy of these asymptotic expressions when predicting the bias of the outputs of moderately large arrays. © 2005 IEEE.

关键词： Signal processing

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Applications and economic analysis of a high reward, low risk cogeneration system

Applications and economic analysis of a high reward, low ris...

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2005 IEEE Power engineering Society General Meeting

作者： Ratajczak, Thomas J. Li, Zuyi IEEE Electrical and Computer Engineering Department Illinois Institute of Technology Chicago IL 60616 United States Masters of Electricity Markets Program Illinois Institute of Technology Chicago Commonwealth Edison Company Chicago ECE Department IIT

ISBN: (纸本)078039156X

The use of a cogeneration system would lead to higher energy efficiencies. The U.S. has seen declined interest before 1978 and renewed interest since then due to the enactment of PURPA. This paper discusses the working principles and cost-effect of cogeneration. Based on an economic analysis, this paper proposes an application of a high reward, low risk cogeneration system for a small food processing plant. Sensitivity analyses are performed, which can be used by site managers to determine a suitable configuration and appropriate operating mode. A system similar to the proposed system appears to have the greatest potential for future use in industrial and commercial applications. ©2005 IEEE.

关键词： Cogeneration plants

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A wheelchair navigation system as a collaborative senior project

A wheelchair navigation system as a collaborative senior pro...

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2005 ASEE Annual Conference and Exposition: The Changing Landscape of engineering and technology Education in a Global World

作者： Burbank, Kenneth Holcomb, John Cooper-Duffy, Karena Prohn, Ken Western Carolina University Cullowhee NC 28723 United States Electrical and Computer Engineering Technology Western Carolina University United States FOCUS Program Meridian Behavioral Health Services Cherokee County NC United States Special Education Program Western Carolina University United States Western Carolina University Teacher Support Program United States

The design of a wheelchair navigation system as a collaborative senior project was discussed. A system was designed using four ultrasonic sensors controlled by a microcontroller board. In this design, a vibrating motor from a cell phone provided the alarm. As an electrical engineering technology senior project, the wheelchair navigation system required the WCU senior to integrate microcontrollers, sensors, programming, power supplies, and to consider the packaging issues.

关键词： Wheelchairs

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High-power packages for phosphor-based white-light-emitting diode lamps

High-power packages for phosphor-based white-light-emitting ...

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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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Reduced-order model-based feedback controller design for subsonic cavity flows

Reduced-order model-based feedback controller design for sub...

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43rd AIAA Aerospace Sciences Meeting and Exhibit

作者： Yuan, X. Caraballo, E. Yan, P. Özbay, H. Serrani, A. DeBonis, J. Myatt, J.H. Samimy, M. Collaborative Center of Control Science Ohio State University United States Department of Electrical and Computer Engineering Department of Mechanical Engineering United States Bilkent Univ. Dept. of Electrical and Electronics Eng. Ankara Turkey NASA Glenn's Quiet Aircraft Technology Program United States Air Force Research Laboratory Air Vehicles Directorate WPAFB United States

This paper explores feedback controller design for cavity flows based on reduced-order models derived using Proper Orthogonal Decomposition (POD) along with Galerkin projection method. Our preliminary analysis shows that the equilibrium of the POD model is unstable and a static output feedback controller cannot stabilize it. We develop Linear Quadratic (LQ) optimal state feedback controllers and LQ optimal observers for the linearized models. The linear controllers and observers are applied to the nonlinear system using simulations. The controller robustness is numerically tested with respect to different POD models generated at different forcing frequencies. An estimation for the region of attraction of the linear controllers is also provided.

关键词： Subsonic flow

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Modeling of spatially periodic dielectric sensors in the presence of a top ground plane bounding the test dielectric

Modeling of spatially periodic dielectric sensors in the pre...

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作者： Sheiretov, Y. Zahn, M. JENTEK Sensors Inc. 110-1 Clematis Ave. Waltham MA 02451-7013 United States Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139 United States Eta Kappa Nu Honor Society Department of Electrical Engineering MIT MIT Course VI-A Electrical Engineering Computer Science Internship Program Liquid Dielectrics Committee International Advisory Committee International Conference on Dielectric Liquids

Semi-analytical models are used to simulate the response of periodic-field electro quasistatic dielectrometry sensors. Due to the periodic structure of the sensors it is possible to use Fourier series methods in combination with collocation point numerical techniques to generate accurate sensor simulations much more efficiently than with the more general finite-element methods. Previously, collocation-point models used to compute the response of periodic field dielectric sensors, also known as Interdigitated Electrode Dielectrometers (IDED), have ignored the contribution of the constant (zero-order) term in the Fourier series expansion of the physical quantities. This is justifiable if the top dielectric material layer under test is infinitely thick, with any top ground plane bounding the dielectric removed too far from the sensor to influence its response. This is the assumption generally made until now in the application of these models. In practice, however, it is impossible to eliminate the cumulative effect of objects at ground potential in the vicinity of the sensor, which in general manifests itself as a ground plane electrode positioned at some effective distance within the top dielectric layer (usually air). In order to eliminate this source of uncertainty in the measurements, we suggest that a grounded electrode be explicitly placed at the top of the dielectric layer in the experimental setup, and its presence be accounted for in the models. Furthermore, in many cases, such as measurements on ceramic thermal barrier coatings, a metal layer is already present behind the material under test. In this paper we present how the models must be modified to account for this ground plane, and what effect it has on the dependence of the sensor response on the material properties. For example, the sensor transcapacitance may no longer be a monotonically increasing function of the material's permittivity, leading to nonuniqueness in permittivity measurements, as some f

关键词： Dielectric devices

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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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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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Adaptive source and channel re-encoding to maximize tandem link performance

Adaptive source and channel re-encoding to maximize tandem l...

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2004 First International Symposium on Control, Communications and Signal Processing, ISCCSP 2004

作者： Gibson, Jerry D. Wei, Bo Media Arts Technology Program Electrical and Computer Engineering Univ. of California Santa Barbara Santa Barbara CA 93106-6065 Department of Electrical Engineering Southern Methodist University Dallas TX 75275

ISBN: (纸本)0780383796

We investigate the issues in voice communications over tandem heterogeneous network connections which require multiple source decoding/encoding operations. While it is known from speech coding research that tandem connections of different speech coders can extract a substantial performance penalty, it is shown that the use of error concealment and source re-encoding can improve system performance in the presence of channel impairments such as bit errors and packet losses. A new protocol is proposed for wireless LANs that reduces retransmissions and discarded packets, and hence reduces system delay and facilitates packet loss concealment.

关键词： Signal encoding

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