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11th Annual International Symposium on Algorithms and Computation, ISAAC 2000

作者： Kubo, Norihiro Muramoto, Katsuhiro Shimozono, Shinichi School of Computer Science and Systems Enginieering Kyushu Inst. of Tech Iizuka820-8502 Japan FAD Iwashita Engineering Inc Nakahara Shinmachi 2-3 Tobata-ku Kitakyushu804-0003 Japan Dept. of Artificial Intelligence Kyushu Inst. of Tech Iizuka820-8502 Japan

ISBN: (纸本)3540412557

We present a quite simple, fast and practical algorithm to find a short cyclic tour that visits a set of points distributed on the plane. The algorithm runs in O(n log n) time with O(n) space, and is simple enough to easily implement on resource restricted machines. It constructs a tour essentially by axis-sorts of the points and takes a kind of the ‘fixed dissection strategy,’ though it neither tries to find best tours in subregions nor optimizes the order among subregions. As well as the worst-case approximation ratio of produced tours, we show that the algorithm is a ‘probabilistic’ constant-ratio approximation algorithm for uniform random distributions. We made computational comparisons of our algorithm, Karp’s partitioning algorithm, Lin-Kernighan local search, Arora’s randomized PTAS, etc. The results indicate that in running time our algorithm overwhelms existing ones, and the average approximation ratio is better or competitive. © Springer-Verlag Berlin Heidelberg 2000.

关键词： Approximation algorithms

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Complexity scalable audio coding algorithm based on wavelet packet decomposition

Complexity scalable audio coding algorithm based on wavelet ...

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International Conference on Signal Processing Proceedings (ICSP)

作者： He Dongmei Gao Wen Wu Jiangqin Dept. of Comput. Sci. & Eng. Harbin Inst. of Technol. China Department of Computer Science and Engineering Harbin Institute of Technology Harbin

In this paper, a complexity scalable audio coding algorithm based on wavelet packet decomposition is proposed. The incomplete wavelet packet decomposition with the property of complexity scalability to the signals is described in this paper. The zerotree coding of the coefficients is implemented which uses the characteristics of human ears and the self-similarity among different subbands wavelet coefficients. This algorithm cannot only be used to achieve transparent quality reconstruction audio at low bit rate, but also enable to support complexity scalable coding and multirate scalable coding. Audio encoding and decoding can be realized in real-time utilizing this algorithm on computers with different levels of computational power. The experimental results indicate that this algorithm is of practical value to the real-time multimedia applications.

关键词： Audio coding Wavelet packets Scalability Humans Ear Wavelet coefficients Bit rate Encoding Decoding Application software

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An environment adaptation method for robust speech recognition

An environment adaptation method for robust speech recogniti...

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International Conference on Signal Processing Proceedings (ICSP)

作者： Han Ji Qing Zhang Lei Wang Chengfa Dept. of Comput. Sci. & Eng. Harbin Inst. of Technol. China Department of Computer Science and Engineering Harbin Institute of Technology China

It is well known that differences between training and testing environments seriously affect speech recognition accuracy. Several environment adaptation techniques have been proposed for eliminating environmental difference, and they are effective when the adaptation data in the testing environment is available beforehand. However, testing environments are not always known beforehand. Therefore, a new framework, which uses testing utterances themselves for adaptation, is effective to cope with such variation. In this paper, a method of testing environment adaptation is proposed, which gradually learns the features of testing environment as the testing procedure, and does not need to get some testing samples beforehand.

关键词： Robustness Speech recognition Acoustic testing Nonlinear distortion Acoustic distortion Additive noise Cepstral analysis Speech enhancement Working environment noise Training data

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Control of electromagnetic environment in low frequency band-harmonics suppression project

Control of electromagnetic environment in low frequency band...

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Annual Conference of Industrial Electronics Society

作者： N. Matsui T. Takeshita Dept. of Electr. & Comput. Eng. Nagoya Inst. of Technol. Japan Department of Electrical and Computer Engineering Nagoya Institute of Technology Nagoya Japan

This paper describes a research project on "Control of electromagnetic environment in low frequency band less than 100 kHz" under the financial support of Japan Society of the Promotion of Science (JSPS). The goal of this research project is in the analysis of harmonic generation mechanism and the effective suppression of harmonics in the field of power electronics.

关键词： Frequency Harmonics suppression Power harmonic filters Power system harmonics Power distribution lines Electromagnetic devices Power generation Control systems Satellites Harmonic analysis

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Verification of a wireless ATM medium-access protocol

Verification of a wireless ATM medium-access protocol

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Asia-Pacific Conference on Software engineering

作者： N. Sidorova M. Steffen Dept. of Mathematics and Computer Science Eindhovan University of Technology Eindhoven Netherlands Inst. für angewandte Mathematik und Informatik Christian-Albrechts-Universität Kiel Kiel Germany

We report on a model checking case study of an industrial medium access protocol for wireless ATM. Since the protocol is too large to be verified by any of the existing checkers as a whole, the verification exploits the layered and modular structure of the protocol's SDL specification and proceeds in a bottom-up, compositional way. The compositional arguments are used in combination with abstraction techniques to further reduce the state space of the system. The verification is primarily aimed at debugging the system. After correcting the specification step by step and validating various untimed and time-dependent properties, a model of the whole control component of the medium-access protocol is built and verified. The significance of the case study is in demonstrating that verification tools can handle complex properties of a model as large as shown.

关键词： Wireless application protocol Debugging State-space methods Electrical equipment industry Error correction Mathematics computer science Access protocols Automatic logic units Context modeling

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Open and safe nested transaction model: Concurrency and recovery

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Journal of Systems and Software 2000年第2期55卷 151-165页

作者： Madria, Sanjay Kumar Maheshwari, S.N. Chandra, B. Bhargava, Bharat Department of Computer Science Purdue University West Lafayette IN 47907 United States Dept. of Comp. Sci. and Engineering Indian Inst. of Technol. New Delhi Hauz Khas India Department of Mathematics Indian Inst. of Technol. New Delhi Hauz Khas India

In this paper, we present an open and safe nested transaction model. We discuss the concurrency control and recovery algorithms for our model. Our nested transaction model uses the notion of a recovery point subtransaction in the nested transaction tree. It incorporates a prewrite operation before each write operation to increase the potential concurrency. Our transaction model is termed `open and safe' as prewrites allow early reads (before writes are performed on disk) without cascading aborts. The systems restart and buffer management operations are also modeled as nested transactions to exploit possible concurrency during restart. The concurrency control algorithm proposed for database operations is also used to control concurrent recovery operations. We have given a snapshot of complete transaction processing, data structures involved and, building the restart state in case of crash recovery.

关键词： Database systems

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Photonic crystal defect microcavities with indium arsenide quantum dots

Photonic crystal defect microcavities with indium arsenide q...

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IEEE Photonics Conference (IPC)

作者： T. Yoshie O. Painter A. Scherer D. Huffaker D. Deppe Dept. of Electr. Eng. California Inst. of Technol. Pasadena CA USA Department of Electrical Engineering California Institute of Technology Pasadena CA USA Microelectronics research Center Department of Electrical and Computer Engineering University of Texas Austin Austin TX USA

The coupling of InAs QDs emission to the two dimensional photonic crystal defect cavity has been demonstrated for the first time and a narrow filtered emission linewidth could be observed. We describe the emission from 2D photonic crystals that contain an InAs QDs active layer. The epitaxial layers were grown on [001] GaAs by molecular beam epitaxy.

关键词： Photonic crystals Microcavities Indium Quantum dots US Department of Transportation Optical pumping Resonance Anisotropic magnetoresistance Etching Superlattices

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Normalized training for HMM-based visual speech recognition

Normalized training for HMM-based visual speech recognition

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IEEE International Conference on Image Processing

作者： Y. Nankaku K. Tokuda T. Kitamura T. Kobayashi Dept. of Comput. Sci. Nagoya Inst. of Technol. Japan Department of Computer Science Nagoya Institute of Technology Nagoya Japan Nagoya Kogyo Daigaku Nagoya Aichi JP Tokyo Institute of Technology Interdisciplinary Graduate School of Science and Engineering Yokohama Japan

This paper presents an approach to estimating the parameters of continuous density HMMs for visual speech recognition. One of the key issues of image-based visual speech recognition is normalization of lip location and lighting conditions prior to estimating the parameters of HMMs. We presented a normalized training method in which the normalization process is integrated in the model training. This paper extends it for contrast normalization in addition to average-intensity and location normalization. The proposed method provides a theoretically-well-defined algorithm based on a maximum likelihood formulation, hence the likelihood for the training data is guaranteed to increase at each iteration of the normalized training. Experiments on the M2VTS database show that the recognition performance can be significantly improved by the normalized training.

关键词： Hidden Markov models Speech recognition Lips Pixel Mouth Maximum likelihood estimation Training data Data mining Databases Vectors

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Stripe-based SPHIT lossy compression of volumetric medical images for low memory usage and uniform reconstruction quality

Stripe-based SPHIT lossy compression of volumetric medical i...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Y. Kim W.A. Pearlman Dept. of Electr. Comput. & Syst. Eng. Rensselaer Polytech. Inst. Troy NY USA Computer and Systems Engineering Department Rensselaer Polytechnic Institute RPI Troy NY USA

This paper presents a low memory implementation of efficient lossy volumetric medical image compression using the set partitioning in hierarchical trees (SPIHT) algorithm. The coding units in this three-dimensional wavelet transform and compression method are short sequences of horizontal stripes cut from the sequence of slices in the volumetric image. As the compression degree increases, the boundaries between adjacent coding units became increasingly visible. Unlike video, where image frames are viewed under dynamic conditions, the volume image is examined under static conditions and must not exhibit such boundary artifacts. In order to eliminate them, we utilize overlapping and averaging both at the intra-slice and inter-slice boundaries between adjacent and successive stripe sequences. Our low memory implementation smooths out considerably the variation in mean squared error among different slices and suffers only an insignificant loss in performance from that of a full memory implementation.

关键词： Image coding Biomedical imaging Image reconstruction Wavelet transforms Medical diagnostic imaging Image generation Hospitals Material storage Image segmentation Kilns

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Tunable red vertical cavity surface emitting lasers using electrostatic actuation

Tunable red vertical cavity surface emitting lasers using el...

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Conference on Optoelectronic and Microelectronic Materials and Devices

作者： J.A. Lott E.M. Ochoa W.J. Siskaninetz M.J. Noble Computer Electrical Engineering Electrical Engineering of Institute Technology OH USA Dept. of Electr. & Comput. Eng. Air Force Inst. of Technol. Wright-Patterson AFB OH USA Air Force Research Laboratory OH USA Air Force Electronic Systems Center MA USA

We report a tunable red vertical cavity surface emitting laser (VCSEL) with a flexible micro-electro-mechanical (MEM) top distributed Bragg reflector. The peak emission wavelength is electrically tunable over a range ... 详细信息

ISBN: (纸本)0780366980

关键词： Vertical cavity surface emitting lasers Tunable circuits and devices Surface emitting lasers Electrostatic actuators Distributed Bragg reflectors Optical surface waves Laser tuning Threshold current RNA Gallium arsenide

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