Tsinghua Science and Technology

Mobile Police Information System Based on Web Services

Hao Yin, Qiang Fu, Chuang Lin, Zhangxi Tan, Rong Ding, Yishu Lin, Yanxi Li, Yanfei Fan

2006, 11(1): 1-7. doi:10.1016/S1007-0214(06)70146-8

Abstract ( 130 ) ( 205 )

The demand for communications anywhere, anytime, and on any device without recording the date is growing with the development of modern information technologies. Current wireless communications enable people to freely exchange information, while web services provide loosely-coupled, language-neutral, and platform-independent ways of linking applications within organizations, across enterprises, and across the Internet. This paper describes a mobile information system for police service, which in...

Linear-in-dB Variable-Gain Downconversion Mixer for Zero Intermediate Frequency Receivers

Dong Feng, Bingxue Shi

2006, 11(1): 8-11. doi:10.1016/S1007-0214(06)70147-X

Abstract ( 192 ) ( 269 )

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In-phase/quadrature (I/Q) mismatch is a key problem in zero intermediate frequency (ZIF) receiver architectures. Although integration and careful layout can alleviate I/Q mismatch, circuit and system level calibrations are also needed due to process variations and variable operating conditions. The amplitude imbalance between I/Q channels was calibrated using a modified R-2R ladder to achieve fine linear-in-dB variable gain. A downconversion mixer working in the 2.4-GHz band was developed for a ...

A Fast Method for Heuristics in Large-Scale Flow Shop Scheduling

Xiaoping Li, Lianchen Liu, Cheng Wu

2006, 11(1): 12-18. doi:10.1016/S1007-0214(06)70148-1

Abstract ( 140 ) ( 216 )

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Fast computation methods are needed for the heuristics of flow shop scheduling problems in practical manufacturing environments. This paper describes a generalized flow shop model, which is an extension of the classical model, in which not all machines are available at time zero. The general completion-time computing method is used to compute completion time of generalized flow shops. The transform classical flow shop to generalized shop (TCG) method is used to transform classical schedules into...

Performance of Adaptive Subchannel Assignment-Based MIMO/OFDM Systems over Multipath Fading Channels

Yahan Pan, Khaled Ben Letaief, Zhigang Cao

2006, 11(1): 19-24. doi:10.1016/S1007-0214(06)70149-3

Abstract ( 164 ) ( 266 )

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Adaptive antenna arrays at both the base and mobile stations can further increase system capacity and improve the quality of service of conventional orthogonal frequency division multiplexing (OFDM) systems. Conventional adaptive antenna array-based multiple-input multiple-output (MIMO)/OFDM systems use the sub-carriers characterized by the largest eigenvalue to transmit the OFDM symbols. This paper describes the performance of adaptive subchannel assignment-based MIMO/OFDM systems over multipat...

Machine Translation Based on Translation Corresponding Tree Structure

Fai Wong, Mingchui Dong, Dongcheng Hu

2006, 11(1): 25-31. doi:10.1016/S1007-0214(06)70150-X

Abstract ( 147 ) ( 207 )

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A representation schema called translation corresponding tree (TCT) has been applied to a Portuguese to Chinese example-based machine translation system. The translation examples are annotated by the representation of the TCT structure. Each TCT describes not only the syntactic structure of the source sentence (i.e., Portuguese in our system) but also the translation correspondences (i.e., Chinese translation). In addition, the TCT nodes describe the corresponding linguistic relationships betwee...

Performance Analysis of Post-Detection Combining for NFSK and DPSK Systems over Arbitrarily Correlated Nakagami Channels with Distinct Fading Parameters

Daming Hang, Xiaowei Cui, Zhigang Cao

2006, 11(1): 32-37. doi:10.1016/S1007-0214(06)70151-1

Abstract ( 126 ) ( 233 )

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For differential phase shift keying (DPSK) and noncoherent frequency shift keying (NFSK) systems over fading channels, the post-detection combining method is a popular means for improving the bit error performance. However, the bit error performance of such systems over Nakagami channels with an arbitrary covariance matrix and real distinct fading parameters has been seldom described in the literature. This paper studies the problem using a generic correlated Nakagami fading model and presents a...

Design and Implementation of SCSI Target Emulator

Jiaming Pan, Jiwu Shu, Suqin Zhang, Weimin Zheng

2006, 11(1): 38-43. doi:10.1016/S1007-0214(06)70152-3

Abstract ( 174 ) ( 223 )

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A SCSI target emulator is used in a storage area network (SAN) environment to simulate the behavior of a SCSI target for processing and responding to I/O requests issued by initiators. The SCSI target emulator works with general storage devices with multiple transport protocols. The target emulator utilizes a protocol conversion module that translates the SCSI protocols to a variety of storage devices and implements the multi-RAID-level configuration and storage visualization functions. Moreover...

B3A: Prompting Cooperation Among Rational Participants in P2P Bulk File Sharing Environments

Ming Chen, Guangwen Yang, Xuezheng Liu, Weimin Zheng

2006, 11(1): 44-49. doi:10.1016/S1007-0214(06)70153-5

Abstract ( 120 ) ( 223 )

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Peer-to-peer (P2P) file sharing systems assume that their users download files in proportion to their sharing. Unfortunately, users are unlikely to do so without an incentive mechanism. Previous solutions to the problem required some types of centralized control, which strays from the spirit of P2P to provide long-term incentives. This paper presents the balance-based bandwidth allocation, B3A, an incentive framework to inspire participants to share files. In the B3A framework, each peer keeps t...

Fuzzy Clustering with Novel Separable Criterion

Zhonghang Yin, Yuangang Tang, Fuchun Sun, Zengqi Sun

2006, 11(1): 50-53. doi:10.1016/S1007-0214(06)70154-7

Abstract ( 154 ) ( 218 )

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Fuzzy clustering has been used widely in pattern recognition, image processing, and data analysis. An improved fuzzy clustering algorithm was developed based on the conventional fuzzy c-means (FCM) to obtain better quality clustering results. The update equations for the membership and the cluster center are derived from the alternating optimization algorithm. Two fuzzy scattering matrices in the objective function assure the compactness between data points and cluster centers, and also strength...

Analysis of Water Management in Proton Exchange Membrane Fuel Cells

Cheng Bao, Minggao Ouyang, Baolian Yi

2006, 11(1): 54-64. doi:10.1016/S1007-0214(06)70155-9

Abstract ( 152 ) ( 217 )

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A two-dimensional, steady-state, isothermal water-management model for a complete proton exchange membrane fuel cell (PEMFC) was developed. The model includes the transport in the diffusion layer and the proton exchange membrane (PEM) with a pseudo-homogeneous model for the cathode catalyst layer. The predicted fuel cell performance with variable cathode porosities compares well with experimental results. The model is then used to investigate the effects of some structural parameters, such as th...

A Functional Framework for Integrating eCRM with Workflow Management Based on Customer Value

W.H. Ip, Bocheng Chen, Henry C.W. Lau, Bing Liang

2006, 11(1): 65-73. doi:10.1016/S1007-0214(06)70156-0

Abstract ( 134 ) ( 233 )

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eCRM ties customer relationship management with e-business. Very often, eCRM is interfaced with other information systems to form a seamless integration and interchange of information both inside and outside an organization—a work flow management system. This integration of business partners, suppliers, and customers is essential in this global competitive market environment. An effective infrastructure and hence an appropriate framework are required to provide the information exchange and data ...

Terrain Identification for Prosthetic Knees Based on Electromyographic Signal Features*

Dewen Jin, Jiankun Yang, Ruihong Zhang, Rencheng Wang, Jichuan Zhang

2006, 11(1): 74-79. doi:10.1016/S1007-0214(06)70157-2

Abstract ( 157 ) ( 259 )

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The features of electromyographic (EMG) signals were investigated while people walking on different terrains, including up and down slopes, up and down stairs, and during level walking at different speeds. The features were used to develop a terrain identification method. The technology can be used to develop an intelligent transfemoral prosthetic limb with terrain identification capability. The EMG signals from 8 hip muscles of 13 healthy persons were recorded as they walked on the different te...

Estimates of Identification Result Disturbances in Parallel Mechanism Calibration*

Meng Gao, Tiemin Li, Xiaoqiang Tang, Guanghong Duan

2006, 11(1): 80-87. doi:10.1016/S1007-0214(06)70158-4

Abstract ( 179 ) ( 236 )

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General QR decomposition of the observation matrix is used to solve identification functions to evaluate identification results of every parameter in parallel mechanism calibrations. A relationship between measured information and identification results is obtained by analyzing numerous matrix transforms and QR decompositions. When distributions of measurement error are determined, random distributions of identification result disturbances (IRDs) can be obtained from this relationship as a funct...

Electrorheological Effects at High Shear Rate*

Ling Ren, Keqin Zhu

2006, 11(1): 88-95. doi:10.1016/S1007-0214(06)70159-6

Abstract ( 139 ) ( 249 )

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Much attention has been given to electrorheological (ER) fluids because of the ER effect, which has been described by a large number of researchers as a notable increase in the apparent viscosity of a fluid upon the application of an electric field. The description of ER effects is, however, not accurate at high shear rates. To clarify the discrepancy, we analyze and compute the apparent viscosity as a function of shear rate for ER fluid flow between rotating coaxial cylinders in the presence of...

Optimization of Unbalanced Multi-stage Logistics Systems Based on Pr黤er Number and Effective Capacity Coding

Hang Xu, Rong Xu, Qingtai Ye

2006, 11(1): 96-101. doi:10.1016/S1007-0214(06)70160-2

Abstract ( 156 ) ( 251 )

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Unbalanced multi-stage logistics systems are optimized using an improved genetic algorithm based on the Pr黤er number and the effective capacity coding. The improved decoding procedure uses the node capacity of the logistics system as an important factor, which influences the decoding procedure. As a result, any Pr黤er number produced stochastically can be decoded to a feasible logistics pattern, which matchs the node capacities of the logistics system. With effective capacity coding, an unbalance...

Expected Value Method for Fuzzy Multiple Attribute Decision Making

Ling Zeng

2006, 11(1): 102-106. doi:10.1016/S1007-0214(06)70161-4

Abstract ( 171 ) ( 232 )

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This paper presents a fuzzy multiple attribute decision-making (FMADM) method in which the attribute weights and decision matrix elements (attribute values) are fuzzy variables. Fuzzy arithmetic and the expected value operator of fuzzy variables are used to develop the expected value method to solve the FMADM problem. A numerical example is given to demonstrate the feasibility and effectiveness of the method.

Parallel Machine Scheduling with Special Jobs

Zhenbo Wang, Wenxun Xing

2006, 11(1): 107-110. doi:10.1016/S1007-0214(06)70162-6

Abstract ( 145 ) ( 299 )

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This paper considers parallel machine scheduling with special jobs. Normal jobs can be processed on any of the parallel machines, while the special jobs can only be processed on one machine. The problem is analyzed for various manufacturing conditions and service requirements. The off-line scheduling problem is transformed into a classical parallel machine scheduling problem. The on-line scheduling uses the FCFS (first come, first served), SWSC (special window for special customers), and FFFS (f...

On a Reduction of the Kadomtsev-Petviashvili Hierarchy

Ting Xue

2006, 11(1): 111-116. doi:10.1016/S1007-0214(06)70163-8

Abstract ( 130 ) ( 217 )

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This paper analyzes the reduction of the well known Kadomtsev-Petviashvili hierarchy. The reduction yields a previously unknown dispersion counterpart of the dispersionless hierarchy which has a Lax function of the form p+u(x)(p??)?1+v(x)(p??)?2. This paper also describes the bihamiltonian structure of the reduced hierarchy using Dirac reduction and proves that the approximation for the reduced hierarchy up to the second order of the dispersion parameter coincides with the hierarchy of integrabl...

Large Eddy Simulations of Three-Dimensional Flows Around a Spur Dike

Xuelin Tang, Xiang Ding, Zhicong Chen

2006, 11(1): 117-123. doi:10.1016/S1007-0214(06)70164-X

Abstract ( 161 ) ( 266 )

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Large eddy simulations were used to model the three-dimensional flows around a non-submerged spur dike. Based on the rigid lid assumption, all these vortex flows around the spur dike, which probably affected the whole flow field, were numerically simulated and analyzed. The largest circulating flow region caused by the spur dike behind it was weak, which would naturally lead to sedimentation for silt-laden twophase flows. Based on the Smagorinsky model, the finite volume method was used to discr...

Push-Over Analysis of the Seismic Behavior of a Concrete-Filled Rectangular Tubular Frame Structure

Jianguo Nie, Kai Qin, Yan Xiao

2006, 11(1): 124-130. doi:10.1016/S1007-0214(06)70165-1

Abstract ( 202 ) ( 239 )

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To investigate the seismic behavior of concrete-filled rectangular steel tube (CFRT) structures, a push-over analysis of a 10-story moment resisting frame (MRF) composed of CFRT columns and steel beams was conducted. The results show that push-over analysis is sensitive to the lateral load patterns, so the use of at least two load patterns that are expected to bound the inertia force distributions is recommended. The M-? curves and N-M interaction surfaces of the CFRT columns calculated either b...

Three-Dimensional Stress and Stress Intensity for Tensioned Flat Plates with Edge Cracks

Yuanqing Wang, Yanmin Wu, Yongjiu Shi, Jianjing Jiang

2006, 11(1): 131-136. doi:10.1016/S1007-0214(06)70166-3

Abstract ( 114 ) ( 256 )

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The stress in the thickness direction is an important factor influencing the fracture behavior of structural members. A stress σy tensioned flat plate with edge cracks is widely used as an analysis model. The stresses σx and σy for the plate model can be acquired from Neuber's solution. However, the solution is applicable only for a perfect plane stress or plane strain state. As a consequence of the thickness of the plate a three-dimensional (3-D) stress state will arise near the crack tip, resu...

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