Tsinghua Science and Technology

Supply Chain Coordination of Loss-Averse Newsvendor with Contract

Long Zhang, Shiji Song, Cheng Wu

2005, 10(2): 133-140. doi:10.1016/S1007-0214(05)70044-4

Abstract ( 138 ) ( 425 )

This paper studies a supply chain model in which a single supplier sells a single product to a single retailer who faces the newsvendor problem. The retailer is loss averse. The results show that the optimal production quantity with decentralized decision making with a wholesale price contract is less than that with centralized decision making. The supply chain can achieve channel coordination with buy back and target rebate contracts. With buy back contracts, the supply chain system profits can...

Stream Weight Training Based on MCE for Audio-Visual LVCSR

Peng Liu, Zuoying Wang

2005, 10(2): 141-144. doi:10.1016/S1007-0214(05)70045-6

Abstract ( 205 ) ( 404 )

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In this paper we address the problem of audio-visual speech recognition in the framework of the multi-stream hidden Markov model. Stream weight training based on minimum classification error criterion is discussed for use in large vocabulary continuous speech recognition (LVCSR). We present the lattice re-scoring and Viterbi approaches for calculating the loss function of continuous speech. The experimental results show that in the case of clean audio, the system performance can be improved by 3...

Isomorphism and Generation of Montgomery-Form Elliptic Curves Suitable for Cryptosystems

Duo Liu, Tao Song, Yiqi Dai

2005, 10(2): 145-151. doi:10.1016/S1007-0214(05)70046-8

Abstract ( 189 ) ( 399 )

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Many efficient algorithms of Montgomery-form elliptic curve cryptology have been investigated recently. At present, there are no reported studies of the isomorphic class of the Montgomery-form elliptic curve over a finite field. This paper investigates the isomorphism of Montgomery-form elliptic curves via the isomorphism of Weierstrass-form elliptic curves and gives a table of (nearly) all the forms of Montgomery-form elliptic curves suitable for cryptographic usage. Then, an algorithm for gene...

Real-Time Multi-View Face Detection and Pose Estimation Based on Cost-Sensitive AdaBoost

Yong Ma, Xiaoqing Ding

2005, 10(2): 152-157. doi:10.1016/S1007-0214(05)70047-X

Abstract ( 133 ) ( 395 )

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Locating multi-view faces in images with a complex background remains a challenging problem. In this paper, an integrated method for real-time multi-view face detection and pose estimation is presented. A simple-to-complex and coarse-to-fine view-based detector architecture has been designed to detect multi-view faces and estimate their poses efficiently. Both the pose estimators and the view-based face/nonface detectors are trained by a cost-sensitive AdaBoost algorithm to improve the generaliz...

Improved MFCC-Based Feature for Robust Speaker Identification

Zunjing Wu, Zhigang Cao

2005, 10(2): 158-161. doi:10.1016/S1007-0214(05)70048-1

Abstract ( 181 ) ( 383 )

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The Mel-frequency cepstral coefficient (MFCC) is the most widely used feature in speech and speaker recognition. However, MFCC is very sensitive to noise interference, which tends to drastically degrade the performance of recognition systems because of the mismatches between training and testing. In this paper, the logarithmic transformation in the standard MFCC analysis is replaced by a combined function to improve the noisy sensitivity. The proposed feature extraction process is also combined ...

Auto-Regressive Models of Non-Stationary Time Series with Finite Length

Wanchun Fei, Lun Bai

2005, 10(2): 162-168. doi:10.1016/S1007-0214(05)70049-3

Abstract ( 142 ) ( 426 )

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To analyze and simulate non-stationary time series with finite length, the statistical characteristics and auto-regressive (AR) models of non-stationary time series with finite length are discussed and studied. A new AR model called the time varying parameter AR model is proposed for solution of non-stationary time series with finite length. The auto-covariances of time series simulated by means of several AR models are analyzed. The result shows that the new AR model can be used to simulate and...

Key Frame Extraction Using Unsupervised Clustering Based on a Statistical Model

Shuping Yang, Xinggang Lin

2005, 10(2): 169-173. doi:10.1016/S1007-0214(05)70050-X

Abstract ( 162 ) ( 420 )

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This paper proposes a novel algorithm for extracting key frames to represent video shots. Regarding whether, or how well, a key frame represents a shot, different interpretations have been suggested. We develop our algorithm on the assumption that more important content may demand more attention and may last relatively more frames. Unsupervised clustering is used to divide the frames into clusters within a shot, and then a key frame is selected from each candidate cluster. To make the algorithm ...

Peripheral Nonlinear Time Spectrum Features Algorithm for Large Vocabulary Mandarin Automatic Speech Recognition

Fadhil H.T. Al-dulaimy, Zuoying Wang

2005, 10(2): 174-182. doi:10.1016/S1007-0214(05)70051-1

Abstract ( 194 ) ( 439 )

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This work describes an improved feature extractor algorithm to extract the peripheral features of point x(ti,fj) using a nonlinear algorithm to compute the nonlinear time spectrum (NL-TS) pattern. The algorithm observes n×n neighborhoods of the point in all directions, and then incorporates the peripheral features using the Mel frequency cepstrum components (MFCCs)-based feature extractor of the Tsinghua electronic engineering speech processing (THEESP) for Mandarin automatic speech recognition ...

Hybrid Decomposition Method in Parallel Molecular Dynamics Simulation Based on SMP Cluster Architecture

Bing Wang, Jiwu Shu, Weimin Zheng, Jinzhao Wang, Min Chen

2005, 10(2): 183-188. doi:10.1016/S1007-0214(05)70052-3

Abstract ( 148 ) ( 393 )

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A hybrid decomposition method for molecular dynamics simulations was presented, using simultaneously spatial decomposition and force decomposition to fit the architecture of a cluster of symmetric multi-processor (SMP) nodes. The method distributes particles between nodes based on the spatial decomposition strategy to reduce inter-node communication costs. The method also partitions particle pairs within each node using the force decomposition strategy to improve the load balance for each node. ...

Modified Diffusion Flux Model for Analysis of Turbulent Gas-Particle Two-Phase Flows

Ruichang Yang, Weiduo Zhou, Kenji Fukuda, Zejian Ju, Zhi Shang

2005, 10(2): 189-195. doi:10.1016/S1007-0214(05)70053-5

Abstract ( 171 ) ( 421 )

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A modified diffusion flux model (DFM) was developed to analyze turbulent multi-dimensional gas-particle two-phase flows. In the model, the solid particles move in a modified acceleration field, g″, which includes the effects of various forces on the particles as if all the forces have the same effect on the particles as the gravity. The accelerations due to various forces are then taken into account in the calculation of the diffusion velocities of the solid particles in the gas-particle two-pha...

Eccentricity Effects on the Crushing History and Energy Absorption of Metal Tubes Collapsed in Concertina Mode

Hongwei Song, Zijie Fan, Huifeng Tan, Qingchun Wang

2005, 10(2): 196-203. doi:10.1016/S1007-0214(05)70054-7

Abstract ( 109 ) ( 411 )

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The classical problem of a round metal tube collapsing in concertina mode when subjected to axial compressive loading has been reexamined both theoretically and experimentally. The model including an eccentricity factor proposed by Wierzbicki et al. and modified by Singace et al. has been taken one step further to obtain the real load-displacement history and to investigate eccentricity effects. The influence of the eccentricity parameter m on the mean crushing load was discussed according to th...

Artificial Neural Network Maximum Power Point Tracker for Solar Electric Vehicle

Theodore Amissah Ocran, Junyi Cao, Binggang Cao, Xinghua Sun

2005, 10(2): 204-208. doi:10.1016/S1007-0214(05)70055-9

Abstract ( 185 ) ( 862 )

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This paper proposes an artificial neural network maximum power point tracker (MPPT) for solar electric vehicles. The MPPT is based on a highly efficient boost converter with insulated gate bipolar transistor (IGBT) power switch. The reference voltage for MPPT is obtained by artificial neural network (ANN) with gradient descent momentum algorithm. The tracking algorithm changes the duty-cycle of the converter so that the PV-module voltage equals the voltage corresponding to the MPPT at any given ...

Project Boundary Setting and Leakage Treatment in CDM Project

Chen Zou, Shujuan Wang, Maosheng Duan, Changhe Chen

2005, 10(2): 209-215. doi:10.1016/S1007-0214(05)70056-0

Abstract ( 128 ) ( 381 )

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Project boundary setting and leakage treatment are two important issues to be considered when a clean development mechanism (CDM) project is being designed. There are still many uncertainties concerning these two issues. This paper reviews the concepts of project boundary setting and leakage in CDM projects, cites the types and sources of leakage, discusses the principles for determining leakage, and gives some proposed methods for dealing with leakage. A case study, using several steps to solve...

Mechanical Characteristics of Oil-Damping Shock Absorber for Protection of Electronic-Packaging Components

Ping Yang

2005, 10(2): 216-220. doi:10.1016/S1007-0214(05)70057-2

Abstract ( 100 ) ( 397 )

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A microstructure oil-damping shock absorber was designed for the protection of electronic-packaging components in vibration-impact environments. The nonlinearity of the oil viscosity, the oil flow characteristics, and the coupling between the oil and the physical structure were included in a mathematical model of the oil-damping shock absorber to attenuate vibrations. The results of multi-parameter-coupled dynamic tests show that the mathematical model accurately simulates the actual physical sy...

A Coupling Model of the Discontinuous Deformation Analysis Method and the Finite Element Method

Ming Zhang, Heqing Yang, Zhongkui Li

2005, 10(2): 221-226. doi:10.1016/S1007-0214(05)70058-4

Abstract ( 165 ) ( 434 )

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Neither the finite element method nor the discontinuous deformation analysis method can solve problems very well in rock mechanics and engineering due to their extreme complexities. A coupling method combining both of them should have wider applicability. Such a model coupling the discontinuous deformation analysis method and the finite element method is proposed in this paper. In the model, so-called line blocks are introduced to deal with the interaction via the common interfacial boundary of ...

Prediction of Perceived Air Quality for Personalized Ventilation Systems

Qingfan Zeng, Rongyi Zhao

2005, 10(2): 227-232. doi:10.1016/S1007-0214(05)70059-6

Abstract ( 246 ) ( 425 )

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The characteristics of the air jet from the outlet of a personalized ventilation system were related to the perceived air quality and ventilation rate. The perceived air quality was expressed as percentage of dissatisfied people for a system supplying isothermal fresh air. The relationship was verified using a thermal manikin with a breathing function in a climate chamber sitting by a desk equipped with a personalized ventilation system. A trace gas was introduced into the climate chamber and fu...

Samples Selection for Artificial Neural Network Training in Preliminary Structural Design

Fei Tong, Xila Liu

2005, 10(2): 233-239. doi:10.1016/S1007-0214(05)70060-2

Abstract ( 198 ) ( 501 )

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An artificial neural network (ANN) is applied in the preliminary structural design of reticulated shells. Major efforts are made to enhance the generalization ability of networks through well-selected training samples. Number-theoretic methods (NTMs) are adopted to generate samples with low discrepancy, i.e., uniformly scattered in the domain, where discrepancy is a quantitative measurement of the uniformity. The discrepancy of the NTM-based sample set is 1/6-1/7 that of samples with equal spaci...

Dispatch Liquidity Theory in a Deregulated Environment

Yu Shen, Qing Xia, Chongqing Kang

2005, 10(2): 240-246. doi:10.1016/S1007-0214(05)70061-4

Abstract ( 167 ) ( 428 )

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Power system security and reliability are more complex issues in a deregulated environment. Various criteria have been considered for power system reliability. In the day-ahead market, a successful trade schedule should be able to accept various disturbances with sufficient flexibility to be adjusted during the re-dispatch process. This paper describes the dispatch liquidity theory and some liquidity indices. The liquidity indices evaluate the effective operating reserves with the network constr...

Application of Six-Sequence Fault Components in Fault Location for Joint Parallel Transmission Line

Chunju Fan, Huarong Cai, Weiyong Yu

2005, 10(2): 247-253. doi:10.1016/S1007-0214(05)70062-6

Abstract ( 218 ) ( 327 )

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A new fault location method based on six-sequence fault components was developed for parallel lines based on the fault analysis of a joint parallel transmission line. In the six-sequence fault network, the ratio of the root-mean square value of the fault current from two terminals is the function of the line impedance, the system impedance, and the fault distance away from the buses. A fault location equation is given to relate these factors. For extremely long transmission lines, the distribute...

Upper Bounds for Ruin Probability with Stochastic Investment Return

Lihong Zhang

2005, 10(2): 254-258. doi:10.1016/S1007-0214(05)70063-8

Abstract ( 176 ) ( 349 )

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Risk models with stochastic investment return are widely held in practice, as well as in more challenging research fields. Risk theory is mainly concerned with ruin probability, and a tight bound for ruin probability is the best for practical use. This paper presents a discrete time risk model with stochastic investment return. Conditional expectation properties and martingale inequalities are used to obtain both exponential and non-exponential upper bounds for the ruin probability.

Ruin Probability in Linear Time Series Model

Lihong Zhang

2005, 10(2): 259-264. doi:10.1016/S1007-0214(05)70064-X

Abstract ( 283 ) ( 322 )

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This paper analyzes a continuous time risk model with a linear model used to model the claim process. The time is discretized stochastically using the times when claims occur, using Doob's stopping time theorem and martingale inequalities to obtain expressions for the ruin probability as well as both exponential and non-exponential upper bounds for the ruin probability for an infinite time horizon. Numerical results are included to illustrate the accuracy of the non-exponential bound.

Area Logistics System Based on System Dynamics Model

Shouping Gui, Qiang Zhu, Lifang Lu

2005, 10(2): 265-269. doi:10.1016/S1007-0214(05)70065-1

Abstract ( 193 ) ( 383 )

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At present, there are few effective ways to analyze area logistics systems. This paper uses system dynamics to analyze the area logistics system and establishes a system dynamics model for the area logistics system based on the characteristics of the area logistics system and system dynamics. Numerical simulations with the system dynamic model were used to analyze a logistic system. Analysis of the Guangzhou economy shows that the model can reflect the actual state of the system objectively and ...

Thermochemical Water Splitting for Hydrogen Production Utilizing Nuclear Heat from an HTGR

Xinxin Wu, Kaoru Onuki

2005, 10(2): 270-276. doi:10.1016/S1007-0214(05)70066-3

Abstract ( 144 ) ( 340 )

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A very promising technology to achieve a carbon free energy system is to produce hydrogen from water, rather than from fossil fuels. Iodine-sulfur (IS) thermochemical water decomposition is one promising process. The IS process can be used to efficiently produce hydrogen using the high temperature gas-cooled reactor (HTGR) as the energy source supplying gas at 1000癈. This paper describes that demonstration experiment for hydrogen production was carried out by an IS process at a laboratory scale....

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