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A flexible framework for HMM based noise robust speech recognition using generalized parametric space polynomial regression

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Science China(Information Sciences) 2011年第12期54卷 2501-2511页

作者： CHENG Ning 1., LIU XunYing 1.2 & WANG Lan 1.1.Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences/The Chinese University of Hong Kong, Hong Kong, China 2 cambridge University{1., cambridge cb2 1.z, uk 1. Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences/The Chinese University of Hong Kong Hong Kong China2. Cambridge University Engineering Department Cambridge CB2 1PZ UK

Handling variable, non-stationary ambient noise is a challenging task for automatic speech recognition (ASR) systems. To address this issue, multi-style, noise condition independent (CI) model training using speech data collected in diverse noise environments, or uncertainty decoding techniques can be used. An alternative approach is to explicitly approximate the continuous trajectory of Gaussian component mean and variance parameters against the varying noise level, for example, using variable parameter hidden Markov model (VP-HMM). This paper investigates a more generalized form of variable parameter HMMs (GVP-HMM). In addition to Gaussian component means and variances, it can also provide a more compact trajectory modeling for tied linear transformations. An alternative noise condition dependent (CD) training algorithm is also proposed to handle the bias to training noise condition distribution. Consistent error rate gains were obtained over conventional VP-HMM mean and variance only trajectory modeling on a media vocabulary Mandarin Chinese in-car navigation command recognition task.

关键词： non-stationary noise generalized variable parameter HMM noise robust speech recognition

Thermoelastic properties of sandwich materials with pin-reinforced foam cores

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Science China(Technological Sciences) 2008年第12期51卷 2059-2074页

作者： LU TianJian1.LIU Tao2,3 & DENG ziChen2,4 1.MOE Key Laboratory of Strength and Vibration,School of Aerospace,Xi’an Jiaotong University,Xi’an 71.049,China 2 department of {1. Mechanics,Northwestern Polytechnical University,Xi’an 71.072,China 3 department of {1.,University of cambridge,cambridge cb2 1.z,uk 4 State Key Laboratory of Structural Analysis of Industrial Equipment,Dalian University of Technology,Dalian 1.6024,China MOE Key Laboratory of Strength and Vibration School of Aerospace Xi’an Jiaotong University Xi’an 710049 China department of {1. Mechanics Northwestern Polytechnical University Xi’an 710072 China department of {1. University of Cambridge Cambridge CB2 1PZ UK State Key Laboratory of Structural Analysis of Industrial Equipment Dalian University of Technology Dalian 116024 China

Pin-reinforced foam is a novel type of sandwich core materials formed by inserting pins(trusses) into a foam matrix to create a truss-like network reinforced foam *** loading,the pins deform predominantly by local stretching whilst the deformation of foam is governed by local *** paper presents a theoretical study on the thermoelasticity of pin-reinforced foam sandwich *** calculate the effective thermoelastic properties of pin-reinforced foam cores,the energy-based homogenization approach is employed to develop a micromechanics-based model,calibrated by the existing experimental *** is found that the stiffness of the sandwich core is mainly governed by pin reinforcements:the foam matrix contributes little to sandwich *** with traditional foam cores without pin reinforcements,the changes in inplane thermal expansion coefficients are not vigorous as a result of pin reinforcements,while the through-thickness thermal expansion coefficient changes *** is also demonstrated that it is possible to design materials with zero or negative thermal expansion coefficients under such a context.

关键词： sandwich panel pin reinforcement analytical solutions homogenization thermoelasticity thermal expansion

An improved approach to the efficient construction of and search operations in motion graphs

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Science China(Information Sciences) 2012年第5期55卷 1042-1051页

作者： GAO Yan 1.CHEN zhiHua 2,CHEN MinGang 3 & SHEN Yang 3 1.Software engineering Institute,East China Normal University,Shanghai 200062,China 2 {1. of Computer Science and engineering,East China University of Science and Technology,Shanghai 200237,China 3 {1. of Computer Science and engineering,Shanghai Jiao Tong University,Shanghai 200240,China 1. Software engineering Institute East China Normal University Shanghai 200062 China2. Department of Computer Science and Engineering East China University of Science and Technology Shanghai 200237 China3. Department of Computer Science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

Motion graphs have been widely used as an effective technique in the synthesis of human *** synthesize well-formed motions,motion graphs require smooth transitions and good ***,the time and costs grow quadratically as the graph size *** this paper,we present a method to set up a hierarchical structure,called a structure *** coarse level of this graph models different motion categories and their transitions,and the fine level mainly captures different motion *** interpolation space method is used to improve the graph connectivity at the fine *** structure guides the establishment of a faster and more realistic graphical *** the building process,this structure also helps with searching the motion graph,by performing a traverse search and placing the findings into a direct look-up table or local search ***,when there is no direct link between the different motions,a navigation map is introduced to conduct an appropriate search path via a series of transition motion *** experimental results indicate that our approach could lower the computation time in construction and searching,while simultaneously providing a richer variety of motion styles.

关键词： motion graph structure table registration curve motion interpolation

Study on H atoms diffusion and adsorption properties of MgH_2-V systems

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Science China(Technological Sciences) 2008年第7期51卷 979-988页

作者： zHOU DianWu1.2, LIU JinShui3 & PENG Ping3 1.State Key Laboratory of Advanced design and Manufacturing for Vehicle Body, Hunan University, Changsha 41.082, China 2 College of Mechanical and Automatic {1., Hunan University, Changsha 41.082, China 3 College of Materials Science and {1., Hunan University, Changsha 41.082, China 1. State Key Laboratory of Advanced design and Manufacturing for Vehicle Body Hunan University Changsha 410082 China 2. College of Mechanical and Automatic engineering Hunan University Changsha 410082 China 3. College of Materials Science and engineering Hunan University Changsha 410082 China

Based on experimental results that VH0.81.MgH2 interface was found during the process of mechanically milling MgH2+5at.%V nanocomposite, H atoms diffusion and adsorption properties of MgH2-V systems have been investigated by using a first-principles plane-wave pseudopotential method based on the density functional theory. The results are as follows. When VH/MgH2 interface is formed due to V alloying MgH2 phase, the vacancy formed by H atoms near VH phase region is more stable than that without V alloying, while vacancy near MgH2 phase region is less stable than that without V alloying. During the process of H atoms diffusion after V alloying, the max migration barrier energy of H atoms in MgH2-V systems is reduced compared with that of MgH2 phase, which means that H atoms diffuse easily. When H diffuses into VH from MgH2 across VH/MgH2 interface, among three substitutions such as the replacement of H for V vacancy, or interstitial site or V atoms, the replacement of H for V vacancy has the strongest diffusion ability, next interstitial site, and finally V atoms site. As far as H adsorbed on different surfaces of VH phase is concerned, physical adsorption is carried out more easily than chemical adsorption, and the behavior of H atoms adsorbed on the surface near VH phase region can be found more easily than that near MgH2 phase region.

关键词： plane-wave pseudopotential theory magnesium hydride diffusion adsorption

Parameter identification theory of a complex model based on global optimization method

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Science China(Physics,Mechanics & Astronomy) 2008年第11期51卷 1722-1732页

作者： QU Jie1. JIN QuanLin2 & XU BingYe3 1.College of Automotive engineering, South China University of Technology, Guangzhou 51.640, China 2 Beijing Research Institute of Mechanical and Electrical Technology, Beijing 1.0083, China 3 {1. of engineering Mechanics, Tsinghua University, Beijing 1.0084, China 1. College of Automotive engineering South China University of Technology Guangzhou 510640 China 2. Beijing Research Institute of Mechanical and Electrical Technology Beijing 100083 China 3. department of {1. Mechanics Tsinghua University Beijing 100084 China

With the development of computer technology and numerical simulation technology, computer aided engineering (CAE) technology has been widely applied to many fields. One of the main obstacles, which hinder the further application of CAE technology, is how to successfully identify the parameters of the selected model. An elementary framework for parameter identification of a complex model is provided in this paper. The framework includes the construction of objective function, the {1. of the optimization method and the evaluation of the identified results, etc. The parameter identification process is described in this framework, taking the parameter identification of the superplastic constitutive model considering grain growth for Ti-6Al-4V at 927°C as an example. The objective function is the weighted quadratic sums of the difference between the experimental and computational data for the stress-strain relationship and the grain growth relationship; the {1.ed optimization method is a hybrid global optimization method, which is based on the feature of the objective function and incorporates the strengths of genetic algorithm (GA), the Levenberg-Marquardt algorithm and the augmented Gauss-Newton algorithm. The reliability evaluation of parameter identification result is made through the comparison between the calculated and experimental results and between the theoretical values of the parameters and the identified ones.

关键词： constitutive model parameter identification theory inverse analysis global optimization

Efficient video cutout based on adaptive multilevel banded method

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Science China(Information Sciences) 2012年第5期55卷 1082-1092页

作者： CHEN MinGang 1.SUI BoCong 1.GAO Yan 2 & MA Lizhuang 1.1.department of Computer Science and {1.,Shanghai Jiao Tong University,Shanghai 200240,China 2 Software {1. Institute,East China Normal University,Shanghai 200062,China 1. department of Computer Science and {1. Shanghai Jiao Tong University Shanghai 200240 China2. Software Engineering Institute East China Normal University Shanghai 200062 China

Although many efficient image cutout approaches have been proposed,it is still a challenge to cut out foreground objects from a video clip because of the costs of time and memory consumption and the difficulty in maintaining temporal coherence for the cutout *** this paper,we propose a novel and efficient video cutout approach by extending a multilevel banded image segmentation method to video *** our method,the segmentation results are propagated frame by frame at the lowest resolution level based on optical flow,and are refined in image pyramids level by level through banded graph *** construct an adaptive narrow band to ensure that the segmentation result falls exactly into the narrow band during *** results show that the video cutout approach based on adaptive multilevel bands dramatically reduces time and memory costs,and achieves ideal segmentation results.

关键词： video object cutout multilevel band graph cuts video segmentation

Asymptotic SEP of MIMO beamforming in two-hop AF relaying systems

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Science China(Information Sciences) 2012年第2期55卷 377-383页

作者： FU YouHua1.HAN YuJie2,YANG LvXi2,zHU WeiPing3 & LIU Chen1.1.chool of Electronic Science and engineering,Nanjing University of Posts and Telecommunications,Nanjing 21.003,China 2School of Information Science and engineering,Southeast University,Nanjing 21.096,China 3department of Electrical and Computer engineering,Concordia University,Montreal H3G 1.8,Canada 1. School of Electronic Science and engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China2. School of Information Science and Engineering Southeast University Nanjing 210096 China3. Department of Electrical and Computer Engineering Concordia University Montreal H3G 1M8 Canada

This paper derives an asymptotic average symbol error probability(SEP)expression for multiple-input multiple-output(MIMO)two-hop amplify-and-forward(AF)relay systems with optimal *** analysis at high signal-to-noise ratio(SNR)quantifies the diversity order and array gain,which are valid for any antenna numbers of the terminals and arbitrary channel fading *** is also proved that the system performance is dominated by the relatively degraded one of the two-hop *** results based on the simple expressions provide valuable insights into the performance and practical design considerations of MIMO AF networks.

关键词： MIMO relay networks optimal beamforming symbol error probability(SEP) diversity order

Target tracking in wireless sensor networks using adaptive measurement quantization

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Science China(Information Sciences) 2012年第4期55卷 827-838页

作者： zHOU Yan 1.2,LI JianXun 2 & WANG DongLi 1.1.Colleage of Information engineering,Xiangtan University,Xiangtan 41.1.5,China 2 {1. of Automation,Shanghai Jiao Tong University,Shanghai 200240,China 1. Colleage of Information engineering Xiangtan University Xiangtan 411105 China2. Department of Automation Shanghai Jiao Tong University Shanghai 200240 China

Quantization/compression is usually adopted in wireless sensor networks (WSNs) since each sensor node typically has very limited power supply and communication *** consider the problem of target tracking in a WSN with quantized measurements in this *** is focused on the design of measurement quantizer with adaptive *** on the probability density function (PDF) of the signal amplitude measured at a random location and by maximizing the entropy,an adaptive design method for quantization thresholds is *** to the nonlinear measuring and quantization models,particle filtering (PF) is adopted in the fusion center (FC) to estimate the target *** Cram'er-Rao lower bounds (CRLBs) for tracking accuracy using quantized measurements are also ***,a simulation example on tracking single target with noisy circular trajectories is provided to illustrate the effectiveness of the proposed approach.

关键词： target tracking wireless sensor network adaptive quantization posterior Cram’er-Rao lower bound

In situ experiments on width and evolution characteristics of excavation damaged zone in deeply buried tunnels

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Science China(Technological Sciences) 2011年第S1期54卷 167-174页

作者： LI ShaoJun 1.FENG XiaTing 1.LI zhanHai 3,CHEN BingRui 1.JIANG Quan 1.WU ShiYong 2,HU Bin 2 &XU JinSong 2 1.State Key Laboratory of Geomechanics and Geotechinical engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071.China 2 Ertan Hydropower Development Company,Ltd.,Chengdu 61.051.China 3 School of Resources and Civil engineering,Northeastern University,Shenyang 1.0004,China 1. State Key Laboratory of Geomechanics and Geotechinical engineering Institute of Rock and Soil Mechanics Chinese Academy of Sciences Wuhan 430071 China3. School of Resources and Civil Engineering Northeastern University Shenyang 110004 China2. Ertan Hydropower Development Company Ltd. Chengdu 610051 China

The seven long tunnels of Jinping II hydropower station are deeply *** width and evolution characteristics of excavation damaged zone(EDz) are the key problem to the design of tunnels excavation and *** order to study this problem,several specific experimental tunnels with different overburden and geometric sizes were excavated at this *** borehole camera,sliding micrometer,cross-hole acoustic wave equipment and acoustic emission apparatus were *** paper introduced the comprehensive in situ experimental methods through pre-installed facilities and pre-drilled *** properties of the surrounding rock mass,including cracks,deformation,elastic wave and micro fractures,were measured during the whole process of the tunnel *** width and characteristics of formation and evolution of tunnels EDz were analyzed under different construction methods involving of TBM and drilling and blasting,the test tunnels were excavated by full-face or two *** relationships between EDz and tunnel geometry sizes,overburden and excavation method were described as *** results will not only contribute a great deal to the analysis of rock mass behavior in deeply buried rock mass,but also provide direct data for support design and rockburst prediction.

关键词： deeply buried tunnel excavation damaged zone evolution characteristics in situ experiments