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11th IEEE International Symposium on Multimedia, ISM 2009

作者： Chen, Shi-Huang Wang, Jhing-Fa Chen, Miao-Hai Sun, Zheng-Wei Liao, Min-Jian Lin, Shun-Chieh Chang, Shyang-Jye Dept. of Computer Science and Information Engineering Shu-Te University Taiwan Dept. of Electrical Engineering National Cheng Kung University China Home Networking Technology Center Industrial Technology Research Institute Taiwan Micro System Technology Center Indust. Technol. Res. Inst. Taiwan

ISBN: (纸本)9780769538907

In this paper, we propose a design of far-field single speaker localization system including noisy speech separation and enhancement with two separated channel microphones. First, we perform noisy speech separation simulations using a Fast-ICA (independent component analysis) with subspacebased speech enhancement. The Fast-ICA can be used to separate the two original source signals - noise and speech from their mixtures. Subspace-based speech enhancement is then utilized to reduce the residual background noise of the separated speech. Second, we calculate time-difference-of-arrival (TDOA) estimation for five directions of both right and left sides in the horizontal plane to realize speaker localization. The TDOA method estimates the time delay difference between the incoming speech signals to microphones using the average magnitude difference function (AMDF) algorithm. Finally we evaluate the localization system under various noisy environments. The experimental results reveal that the applicability of a system with noisy speech separation and enhancement, particularly for the front directions. © 2009 IEEE.

关键词： Time difference of arrival

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Numerical analysis of one-shot full-range FD-OCT system based on orthogonally polarized light

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Optics Communications 2009年第14期282卷 3040-3045页

作者： Cheng, Hsu-Chih Huang, Jen-Fa Hsieh, Yi-Hua Dept. of Electro-Optics Engineering National Formosa University No. 64 Wunhua Rd Huwei Township Yunlin County 63201 Taiwan Advanced Optoelectronic Technology Center National Cheng Kung University Tainan Taiwan Institute of Computer and Communications National Cheng Kung University Tainan Taiwan Dept. of Electrical Engineering National Cheng Kung University Tainan Taiwan

Full-range Fourier domain optical coherence tomography (FD-OCT) is generally achieved using a phase shifting algorithm. A novel design is presented for a one-shot full-range Fourier domain optical coherence tomography (FD-OCT) system utilizing orthogonally polarized light. The phase-shifted interferograms required to reconstruct the sample structure are obtained using an apochromatic quarter-wave retarder rather than a mechanical scanning operation, and thus the imaging results are free of vibrational-induced errors. The numerical analysis shows that it enhances the quality of high resolution FD-OCT and reduces the acquisition time. Moreover, the simulation results show that the proposed system is robust toward both the presence of noise in the power spectrum of the super luminescent diode (SLD) and a slight non-orthogonality of the two light beams incident on the spectrum analyzers, respectively. © 2009 Elsevier B.V. All rights reserved.

关键词： Light polarization

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Neuroadaptive model following controller design for non-affine non-square aircraft system

Neuroadaptive model following controller design for non-affi...

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作者： Rajagopal, Karthikeyan Mannava, Anusha Balakrishnan, S.N. Nguyen, Nhan Krishnakumar, Kalmanje Dept. of Mechanical and Aerospace Engineering Missouri University of Science and Technology United States Dept. of Electrical and Computer Engineering Missouri University of Science and Technology United States IRAC Project NASA Ames Research Center United States

ISBN: (纸本)9781563479786

Aircrafts with high performance requirements or structural damage, often operate in conditions characterized by rapidly changing nonlinear aerodynamic phenomena. A neural network based model-following adaptive control design is proposed in this paper for stable control of aircrafts in such scenarios. These systems have control dependent nonlinearities making their mathematical characterization non-affine in control and they are usually nonsquare too. The uncertainties that occur during the flight are estimated online with weight update adaptation laws derived by using the Lyapunov theory to ensure boundedness of the estimation errors and the weights. The nonsquare system model is re-structured by using slack variables to facilitate the design of control using the dynamic inversion technique. Typically, when large changes appear in the aerodynamic derivatives, fast adaptation is required to ensure the system stability. But the drawback with using high adaptive gains is that they could result in high frequency oscillations in the control signal that excite the unmodeled dynamics of the plant. A novel observer structure is employed in this paper that enables fast adaptation without inducing any high frequency oscillations. The proposed method is applied to the short period dynamics of a fighter aircraft and is compared with the recently popular L1 adaptive control technique. Simulation results demonstrate the potential of the proposed method. Copyright © 2009 by S.N. Balakrishnan and K. Rajagopal.

关键词： System stability

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Sub-picosecond optical switching in the near-infrared using negative index metamaterials

Sub-picosecond optical switching in the near-infrared using ...

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International Quantum Electronics Conference, IQEC 2009

作者： Dani, Keshav M. Ku, Zahyun Upadhya, Prashanth C. Prasankumar, Rohit P. Brueck, S.R.J. Taylor, Antoinette J. Center for Integrated Nanotechnologies Los Alamos National Laboratory Los Alamos NM 87545 United States Center for High Technology Materials and Electrical and Computer Engineering Dept. Univ. of New Mexico United States

We study the ultrafast non-linear optical properties of a negative-index metamaterial. In particular, we achieve sub-picosecond optical switching allowing for terabits per second modulation at telecommunication wavele... 详细信息

ISBN: (纸本)9781557528698

关键词： Infrared devices

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Translation corpus source and size in bilingual retrieval

Translation corpus source and size in bilingual retrieval

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2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, NAACL-HLT 2009

作者： McNamee, Paul Mayfield, James Nicholas, Charles Human Language Technology Center of Excellence Johns Hopkins University BaltimoreMD21218 United States Dept. of Computer Science and Electrical Engineering UMBC BaltimoreMD21250 United States

ISBN: (纸本)9781932432428

This paper explores corpus-based bilingual retrieval where the translation corpora used vary by source and size. We find that the quality of translation alignments and the domain of the bitext are important. In some settings these factors are more critical than corpus size. We also show that judicious choice of tokenization can reduce the amount of bitext required to obtain good bilingual retrieval performance. © 2009 Association for Computational Linguistics

关键词： Translation (languages)

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Autonomously normalized horizontal differentials as features for HMM-based omni font-written OCR systems for cursively scripted languages

Autonomously normalized horizontal differentials as features...

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2009 IEEE International Conference on Signal and Image Processing Applications, ICSIPA09

作者： Attia, Mohamed Rashwan, Mohsen A.A. El-Mahallawy, Mohamed S.M. Engineering Company for the Development of Computer Systems RDI Egypt Dept. of Electronics and Electrical Communication Faculty of Eng. Cairo Univ. Egypt Arab Academy for Science and Technology and Maritime Transport AAST-MT Egypt

ISBN: (纸本)9781424455614

Automatic font-written Optical Character Recognition (OCR) is highly desirable for numerous modern information technology (IT) applications. Reliable font-written OCR's for Latin scripts are readily in use since long. For cursively scripted languages, that are the mother tongues of over one fourth of the world population, such OCR's are however not available at a robust and reliable performance. In this regard, the main challenge is the mandatory connectivity of characters/ligatures (i.e. graphemes) that has to be resolved simultaneously upon the recognition of these graphemes. Among the various approaches tried over decades, Hidden Markov Models (HMM)-based OCR's seem to be the most promising as they capitalize on the ability of HMM decoders to achieve segmentation and recognition simultaneously similar to the widely used HMM-based automatic speech recognition (ASR). Unlike ASR's, what is missing in HMM-based OCR's is the definition of a rigorously founded features vector capable to robustly achieving minimal "font type/size-independent" (omnifont) word error rates comparable to those realized with Latin scripts. Here comes the contribution of this paper that introduces such a sound features vector design, and experimentally shows its superiority in this regard.

关键词： Optical character recognition

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Instantaneous baseline damage detection using a low power guided waves system 7

Instantaneous baseline damage detection using a low power gu...

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7th International Workshop on Structural Health Monitoring: From System Integration to Autonomous systems, IWSHM 2009

作者： Park, S. Anton, S.R. Inman, D.J. Kim, J.-K. Ha, D.S. Department of Civil and Environmental Engineering Sungkyunkwan University Suwon Gyeonggi440-746 Korea Republic of Center for Intelligent Material Systems and Structures Dept. of Mechanical Engineering Virginia Tech BlacksburgVA24061 United States VTVT Laboratory Dept. of Electrical and Computer Engineering Virginia Tech BlacksburgVA24061 United States

ISBN: (纸本)9781605950075

In recent years, new structural health monitoring (SHM) methodologies with a concept of "instantaneous baseline damage detection" are being developed by many researchers, since it has been found that the most of SHM technologies are too vulnerable to environmental and/or operational variations. In this context, this paper presents online instantaneous baseline structural damage detection using a low cost and low power, in-situ guided waves-SHM system. Firstly, four small, low cost and light weight smart piezoelectric ceramic (PZT) patches are surface-mounted and assumed to have the same bonding conditions to detect structural defects on an aluminum plate. Then, a miniaturized low power guided waves-SHM system with a digital signal processing (DSP) module is employed for signal generation/excitation, signal sensing, and data processing. The instantaneous baseline damage detection based on discrete wavelet transform (DWT) analysis is carried out on the DSP module. Finally, effects of Lamb waves due to artificial "cut-damage' with different locations are investigated using both "pitch-catch" and "pulse-echo" wave propagation schemes. Conclusively, this study shows a good potential for online and in-situ crack monitoring on panel structures such as an aircraft wing.

关键词： Damage detection

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A Simulation Study of Consensus Speed over Scale-Free Networks

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IFAC Proceedings Volumes 2009年第22期42卷 74-79页

作者： Wei Sun YangQuan Chen Dept. of Automatic Control Beijing Institute of Technology Beijing 100081 China Center for Self-Organizing and Intelligent Systems (CSOIS) Dept. of Electrical and Computer Engineering Utah State University Logan UT 84322 USA

Scale-free network and consensus among multiple agents have both drawn quite much attention. To investigate the consensus speed over scale-free networks is the main topic in this paper. Given a set of different values for the power-law distribution parameter γ, and a set of different values for the minimum degree ( d min ) for the nodes, the algebraic connectivity (λ 2 ) of the network topology is studied, as well as the time ( t c ) (or iteration ( k c ), for discrete algorithm) taken to reach consensus. The results exhibit that λ 2 decreases while γ increases. The λ 2 increases monotonically as d min grows, and they fit very well in a linear relationship. t c (or k c ) decreases as γ reduces and d min increases. Via observing the behavior of the largest eigenvalue (λ n ) of the Laplacian of the network topology, we draw the conclusion that the robustness over time delays declines while the robustness over node-failures and edge-failures increases.

关键词： Scale-free network consensus algebraic connectivity network robustness

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On global clustering algorithm: Layer-oriented approach for first/last node dying applications in wireless sensor networks

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International Review on computers and Software 2009年第2期4卷 229-240页

作者： Mazinani, S.M. Yaghmaee, M.H. Tashtarian, F. Honary, M.T. Chitizadeh, J. Computer and Communication Research Center Mashhad Iran Dept. of Electrical Engineering Ferdowsi University of Mashhad Iran Dept. of Computer Engineering Ferdowsi University of Mashhad Iran Dept. of Computer and Information Technology Islamic Azad University of Qazvin Iran

Clustering methods are potentially the framework for power-conserving wireless sensor networks. These methods are among the most effective approaches aiming for prolonging the lifetime. Power-limited nature of the employed devices in wireless networks made the conventional clustering approaches to mainly focus on selecting cluster heads -which are the central points within a cluster- among the nodes with more remaining energy. Periodic rotation of this task -being a cluster head- between nodes leads to distribute the energy consumption. In singlehop wireless sensor network, Hot-Spot problem arises when the further cluster heads to the base station excessively utilize their energy due to the distant communications. The main purpose of this paper is to provide a layering-based clustering algorithm that aims at directly optimizing the nodes' longevity by considering the application in which they operate and the relationship between the width of each layer and its overall lifetime. Two main types of applications are dealt with;First node dying and Last node dying applications. Analytical methods are employed to study the impacts of intra-cluster and singlehop communication traffic loads on the average layer's lifetime that is formulated as an optimization problem. © 2009 Praise Worthy Prize S.r.l. - All rights reserved.

关键词： Clustering algorithms

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A new middleware for multipurpose applications in wireless sensor networks

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International Review on computers and Software 2009年第2期4卷 241-253页

作者： Mazinani, S.M. Yaghmaee, M.H. Honary, M.T. Tashtarian, F. Chitizadeh, J. Computer and Communication Research Center Mashhad Iran Dept. of Electrical Engineering Ferdowsi University of Mashhad Iran Dept. of Computer Engineering Ferdowsi University of Mashhad Iran Dept. of Computer and Information Technology Islamic Azad University of Qazvin Iran

Dramatic development of the wireless sensor networks (WSNs) in several applications is seeking for multi-application implementation of such networks. In this way, the middlewares contain a runtime environment that supports and coordinates multiple applications. In this paper, a middleware is proposed to support multi-application network that simultaneously satisfies the quality of service (QoS) requirements of users, that is the response time and data accuracy, and that of network that is optimizing the network resources (i.e. energy) utilization. Organizing nodes into clusters and preparing them to efficiently report data of any detected event, the middleware features an inheritance pattern among nodes that trains them to support multiple events. More over, employing the Data Integration among nodes not only reduces the energy consumptions for data reporting but also increases the data accuracy of every detected event. © 2009 Praise Worthy Prize S.r.l. - All rights reserved.

关键词： Quality of service

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