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Annual IEEE Conference on Applied Power Electronics Conference and Exposition (APEC)

作者： Zhuxian Xu Fred Wang Center for Ultra-wide-area Resilient Electric Energy Transmission Networks Department of Electrical Engineering and Computer Science University of Tennessee Knoxville TN USA National Transportation Research Center Oak Ridge National Laboratory Knoxville TN USA

This paper investigates the short-circuit capability and the failure mechanisms of Si trench gate field-stop IGBT under high temperature operation conditions through experiments. First, the test circuits are proposed for IGBT short circuit capability evaluation in different types of short circuit conditions. A hardware setup is built accordingly, and used to evaluate experimentally the IGBT short circuit failures caused by thermal destruction, thermal runaway and latch-up at both 25°C and 200°C. The critical short circuit time is given for high temperature operation under different short circuit conditions. The experimental results show that although the critical short circuit time is reduced at 200°C operation, it is still adequate for the protection circuit to shut down the devices safely. The Si trench gate field-stop IGBT exhibits good short circuit ruggedness at 200°C operation.

关键词： Insulated gate bipolar transistors Logic gates Circuit faults Integrated circuits Inductance Silicon Temperature measurement

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Integrated Approach to Hypersonic Vehicle Modeling

Integrated Approach to Hypersonic Vehicle Modeling

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Chinese Control Conference

作者： Xiaofeng Su Yingmin Jia Junping Du Fashan Yu The Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Key Laboratory of Mathematics Informatics and Behavioral Semantics (LMIB) Ministry of Education SMSS Beihang University (BUAA) Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications School of Electrical Engineering and Automation Henan Polytechnic University

ISBN: (纸本)9781467325813

This paper is devoted to the modeling problem of hypersonic vehicle with significant couplings. An integrated approach is developed to analytically model the dynamics of hypersonic vehicle, in which the effects of variable mass, spherical rotating earth, and couplings among the sub-models are considered. Furthermore, a preliminary analysis is conducted using the general data of a hypersonic vehicle. The simulation results show that the maximum of the Coriolis force can reach values up to 7.02% of the vehicle weight, and that the thermal load determined by the nonuniform aerodynamic heating and the properties of the structure has a significant influence on the elastic deformation.

关键词： Hypersonic vehicle modeling Inertial dynamics Aerodynamics Elasticity Heating hypersonic vehicles Aerodynamics elasticity Coriolis force Vehicle weight Heating Couplings Thermal loading elastic deformation

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Generating emphasis from neutral speech using hierarchical perturbation model by decision tree and support vector machine

Generating emphasis from neutral speech using hierarchical p...

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International Conference on Audio, Language and Image Processing, ICALIP

作者： Fanbo Meng Zhiyong Wu Helen Meng Jia Jia Lianhong Cai Tsinghua National Laboratory for Information Science and Technology (TNList) Department of Computer Science and Technology Tsinghua University Beijing China Department of Systems Engineering and Engineering Management The Chinese University of Hong Kong Hong Kong China Tsinghua-CUHK Joint Research Center for Media Sciences Technologies and Systems Graduate School at Shenzhen Tsinghua University Shenzhen China Tsinghua University Beijing Beijing CN

In a computer-aided pronunciation training (CAPT) system, corrective feedback is desired to provide contrastive comparisons between user's and canonical pronunciations. This paper presents a hierarchical perturbation model to generate emphasis for English by modifying acoustic features of neutral speech to highlight such important speech segments. Synthesis of emphasis needs to be realized hierarchically at word, syllable and phone layers. A two-pass decision tree is constructed to cluster acoustic variations between emphatic and neutral speeches. The questions for decision tree construction are designed according to the above layers. The questions related to word and syllable layers are used to construct the main tree and then the questions related to phone layer are used to expand the leaves of main tree (deriving a set of subtrees). Support vector machines (SVMs) are used to predict acoustic variations for all the leaves of main tree (at word and syllable layers) and sub-trees (at phone layer). Experiments indicate that the proposed hierarchical perturbation model can generate emphatic speech with high quality for both naturalness and emphasis.

关键词： Speech Acoustics Decision trees Support vector machines Training Feature extraction Reactive power

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Stochastic H_2 Optimal Control of Discrete-Time Markov Jump systems with Periodic Coefficients

Stochastic H_2 Optimal Control of Discrete-Time Markov Jump ...

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American Control Conference

作者： Hongji Ma Yingmin Jia Junping Du Fashan Yu Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Beijing 100191 China Beijing Key Laboratory of Intelligent Telecommunications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo 454000 Henan China

ISBN: (纸本)9781457710957

In this paper, the H_2 optimal state-feedback control problem is investigated for discrete-time Markov jump systems subject to periodic coefficients and multiplicative noise. First of all, an exhaustive analysis is pursued to set up an H_2 performance criterion (H_2 norm), which can be characterized by the periodic solutions of two generalized Lyapunov equations. Based on the obtained H_2 norm, the H_2 optimal state-feedback controller is designed in terms of the stabilizing solution of a discrete-time generalized Riccati equation with periodic coefficients. Moreover, this stabilizing solution can be computed efficiently by the available iterative algorithm.

关键词： Markov processes Noise Educational institutions Riccati equations Optimal control

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Bayesian tomographic reconstruction for high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM)

Bayesian tomographic reconstruction for high angle annular d...

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IEEE/SP Workshop on Statistical Signal Processing (SSP)

作者： Singanallur Venkatakrishnan Lawrence Drummy Michael Jackson Marc De Graef Jeff Simmons Charles Bouman Purdue University School of Electrical and Computer Engineering West Lafayette IN USA Wright-Patterson Air Force Base Air Force Research Lab Dayton OH BlueQuartz Software Springboro OH USA Department of Material Science and Engineering Carnegie Mellon University Pittsburgh PA USA Air Force Research Laboratory Dayton OR USA

HAADF-STEM data is increasingly being used in the physical sciences to study materials in 3D because it is free from the diffraction effects seen in Bright Field STEM data and satisfies the projection requirement for tomography. Typically, reconstruction is performed using Filtered Back Projection (FBP) or the SIRT algorithm. In this paper, we develop a Bayesian reconstruction algorithm for HAADF-STEM tomography which models the image formation, the noise characteristics of the measurement, and the inherent smoothness in the object. Reconstructions of polystyrene functionalized Titanium dioxide nano particle assemblies show results that are qualitatively superior to FBP and SIRT reconstructions, significantly suppressing artifacts and enhancing contrast.

关键词： Signal processing Conferences Image reconstruction Abstracts Nickel Estimation

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Detection and emphatic realization of contrastive word pairs for expressive text-to-speech synthesis

Detection and emphatic realization of contrastive word pairs...

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International Symposium on Chinese Spoken Language Processing

作者： Chunrong Li Zhiyong Wu Fanbo Meng Helen Meng Lianhong Cai Tsinghua-CUHK Joint Research Center for Media Sciences Technologies and Systems Graduate School at Shenzhen Tsinghua University Shenzhen China Tsinghua National Laboratory for Information Science and Technology (TNList) Department of Computer Science and Technology Tsinghua University Beijing China Department of Systems Engineering and Engineering Management Chinese University of Hong Kong Shatin New Territories Hong Kong China Tsinghua University Beijing Beijing CN

This paper addresses the problem of automatic detection of contrastive word pairs and their acoustic realization in emphasis for expressive text-to-speech (TTS) synthesis in English. Support vector machines (SVMs) have been used to automatically detect contrastive word pairs from lexical features, syntactic dependencies and semantic relations. A much better performance is achieved by adding accent ratio and word identity features. Hidden Markov model (HMM) based speech synthesis is then used to generate emphatic speeches by putting emphasis on the detected contrastive word pairs. Subjective experiments show that most of the listeners consider putting emphasis on contrastive word pairs is more acceptable than on non-contrastive word pairs. This indicates the importance of the accurate detection of contrastive word pairs.

关键词： Hidden Markov models Speech Feature extraction Semantics Speech synthesis Support vector machines Syntactics

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Lane Keeping Control for Autonomous 4WS4WD Vehicles Subject to Wheel Slip Constraint

Lane Keeping Control for Autonomous 4WS4WD Vehicles Subject ...

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American Control Conference

作者： Changfang Chen Yingmin Jia Junping Du Fashan Yu Seventh Research Division and the Department of Systems and Control Beihang University (BUAA) Beijing 100191 China Beijing Key Laboratory of Intelligent Telecom-munications Software and Multimedia School of Computer Science and Technology Beijing University of Posts and Telecommunications Beijing 100876 China School of Electrical Engineering and Automation Henan Polytechnic University Jiaozuo 454000 Henan China

ISBN: (纸本)9781457710957

This paper proposes a robust control scheme that prevents an autonomous 4WS4WD vehicle from lane departure and wheel skidding in presence of road curvature and aerodynamic drag. The control objectives can be specified as various closed-loop specifications, such as lane keeping, wheel slip constraint and disturbance attenuation. An LMI approach is used to deal with these objectives simultaneously, which combines the quadratic stabilization technique with constraints on inputs. Simulation results show that the proposed controller effectively limits the combined wheel slip and improves the lane keeping performance.

关键词： Wheels Vehicles Roads Tires Friction Aerodynamics Vehicle dynamics

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A model-based method with joint sparsity constraint for direct diffusion tensor estimation

A model-based method with joint sparsity constraint for dire...

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IEEE International Symposium on Biomedical Imaging

作者： Yanjie Zhu Yin Wu Yuanjie Zheng Ed X. Wu Leslie Ying Dong Liang Paul C. Lauterbur Research Centre for Biomedical Imaging Shenzhen Institutes of Advanced Technology Key Laboratory of Health Informatics Chinese Academy of Sciences Shenzhen China Department of Radiology University of Pennsylvania PA USA Laboratory of Biomedical Imaging and Signal Processing Department of Electrical and Electronic Engineering University of Hong Kong Pokfulam Hong Kong China Department of Electrical Engineering and Computer Science University of Wisconsin Milwaukee Milwaukee WI USA

Diffusion tensor imaging (DTI) has been widely used for nondestructive characterization of microstructures of myocardium or brain connectivity. It requires repeated acquisition with different diffusion gradients. The long acquisition time greatly limits the clinical application of DTI. In this paper, a novel method, named model-based method with joint sparsity constraint (MB-JSC), effectively incorporates the prior information on the joint sparsity of different diffusion-weighted images in direct estimation of the diffusion tensor from highly undersampled k-space data. Experimental results demonstrate that the proposed method is able to estimate the diffusion tensors more accurately than the existing method when a high net reduction factor is used.

关键词： Tensile stress Diffusion tensor imaging Image reconstruction Joints Compressed sensing Biological system modeling

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Strategic Robust Mixed Model Assembly Line Balancing Based on Scenario Planning

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Tsinghua science and Technology 2011年第3期16卷 308-314页

作者：徐炜达肖田元 National Laboratory for Information Science and Technology National Computer Integrated Manufacturing Systems Engineering Research CenterDepartment of AutomationTsinghua University

Assembly line balancing involves assigning a series of task elements to uniform sequential stations with certain restrictions. Decision makers often discover that a task assignment which is optimal with respect to a deterministic or stochastic/fuzzy model yields quite poor performance in reality. In real environments, assembly line balancing robustness is a more appropriate decision selection guide. A robust model based on the α worst case scenario is developed to compensate for the drawbacks of traditional robust criteria. A robust genetic algorithm is used to solve the problem. Comprehensive computational experiments to study the effect of the solution procedure show that the model generates more flexible robust solutions. Careful tuning the value of α allows the decision maker to balance robustness and conservativeness of as- sembly line task element assignments.

关键词： mixed model assembly line balancing robust scenario planning genetic algorithm

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Cervical inlet patch-optical coherence tomography imaging and clinical significance

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World Journal of Gastroenterology 2012年第20期18卷 2502-2510页

作者： Chao Zhou Tejas Kirtane Tsung-Han Tsai Hsiang-Chieh Lee Desmond C Adler Joseph M Schmitt Qin Huang James G Fujimoto Hiroshi Mashimo Department of Electrical Engineering and Computer Science Research Laboratory of Electronics Massachusetts Institute of Technology 77 Massachusetts Avenue Cambridge MA 02139-4307 United States Gastroenterology Section VA Boston Healthcare System/Harvard School of Medicine 150 S. Huntington Avenue Boston MA 02131 United States Light Lab Imaging-St Jude Medical Inc. Westford MN 55117-9983 United States

AIM:To demonstrate the feasibility of optical coherence tomography(OCT)imaging in differentiating cervical inlet patch(CIP)from normal esophagus,Barrett'sesophagus(BE),normal stomach and duodenum. METHODS:This study was conducted at the Veterans Affairs Boston Healthcare System(VABHS).Patients undergoing standard esophagogastroduodenoscopy at VABHS,including one patient with CIP,one representative patient with BE and three representative normal subjects were *** light video endoscopy was performed and endoscopic 3D-OCT images were obtained in each patient using a prototype OCT *** OCT imaging probe passes through the working channel of the endoscope to enable simultaneous video endoscopy and 3D-OCT examination of the human gastrointestinal(GI)*** hematoxylin and eosin(H and E)histology was performed on biopsy or endoscopic mucosal resection specimens in order to compare and validate the 3D-OCT data. RESULTS:CIP was observed from a 68-year old male with gastroesophageal reflux *** CIP region appeared as a pink circular lesion in the upper esophagus under white light *** imaging over the CIP region showed columnar epithelium structure,which clearly contrasted the squamous epithelium structure from adjacent normal esophagus.3D-OCT images obtained from other representative patients demonstrated distinctive patterns of the normal esophagus,BE,normal stomach,and normal duodenum ***,such as squamous epithelium,lamina propria, muscularis mucosa,muscularis propria,esophageal glands,Barrett's glands,gastric mucosa,gastric glands, and intestinal mucosal villi were clearly observed with OCT and matched with H and E *** results demonstrated the feasibility of using OCT to evaluate GI tissue morphology in situ and in real-time. CONCLUSION:We demonstrate in situ evaluation of CIP microstructures using 3D-OCT,which may be a useful tool for future diagnosis and follow-up of patients with CIP.

关键词： Cervical inlet patch Heterotopic gastric mucosa Optical coherence tomography Optical biopsy Barrett’s esophagus

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