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A note on the 2-connectivity in one-dimensional ad hoc networks

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science china(Information sciences) 2011年第1期54卷 123-128页

作者： SHANG YiLun department of Mathematics,shanghai jiao tong university, shanghai 200240,{3. 1. department of Mathematics Shanghai Jiao Tong University Shanghai 200240 China

2-connectivity is the basic graph theoretical metric for fault tolerance to node failures,and it is an extremely desirable property in network *** a one-dimensional finite ad hoc network formed by n nodes uniformly and independently distributed in a closed interval[0,z](z∈R+),we give a closed form expression for the probability that a connected one-dimensional finite ad hoc network becomes disconnected after removing a *** also sketch a procedure of finding the exact formula for 2-connectivity in a one-dimensional ad hoc network.

关键词： ad hoc network one-dimensional network 2-connectivity

A RHEOLOGICAL MODEL FOR POLYMER MELTS WITH INTERNAL STRUCTURE IN FLOW FIELDS

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Chinese Journal of Polymer science 1999年第2期17卷 151-158页

作者： Chi-Xing Zhou department of Polymeric Materials science and Engineering, shanghai jiao tong university, {3., china shanghai jiao tong Univ Dept Polymer Mat Sci & Engn Shanghai 200240 Peoples R China

Conceptually, an imagined conformation ellipsoid is supposed to represent the shape of a polymer chain for polymer melts in flow fields and to be equivalent to the volume element in a mathematical sense in continuum mechanics. A power law dependence of shear modulus of polymer melts on detC, referred to as envelope volume, is proposed. Based on those assumptions and the non-linear relation of shear modulus, a phenomenological viscoelastic model is derived. The model is tested in simple shear flow, simple elongational flow, oscillatory shear flow, and relaxation process after flow suddenly stopped. The results show that the model works well to predict the change of internal structure and viscoelastic performance of polymer melts in flow fields.

关键词： polymer melts rheological model polymer conformation flow fields

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 department of computer science and Engineering,East china university of science and Technology,shanghai 20023.,china 3.department 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

Identity based signature scheme based on cubic residues

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science china(Information sciences) 2011年第10期54卷 2001-2012页

作者： XING DongSheng,CAO ZhenFu & DONG XiaoLei department of computer science and Engineering,{3.,shanghai 200240,china 1. department of computer science and Engineering Shanghai Jiao Tong University Shanghai 200240 China

We propose a novel method to compute a cubic root of a cubic residue in Eisenstein *** applying our method,a new identity based signature scheme is proposed based on cubic *** formally prove that our scheme is secure against existential forgery on the adaptive chosen message and identity attacks assuming the hardness of *** scheme is the first identity based signature scheme based on cubic residues.

关键词： Eisenstein ring identity based signature cubic residue factoring random oracle proven security

WATER ENTRY OF A WEDGE BASED ON SPH MODEL WITH AN IMPROVED BOUNDARY TREATMENT

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Journal of Hydrodynamics 2009年第6期21卷 750-757页

作者： GONG Kai LIU Hua WANG Ben-long department of Engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200240 China

The hydrodynamic problem of a two-dimensional wedge entering water is studied based on Smoothed Particle Hydrodynamics （SPH） model. A non-reflection boundary treatment for SPH method is proposed to reduce the reflection of sound waves. The boundary pressure is obtained using an improved coupling boundary treatment approach, which is validated by comparing the simulation results with experimental and analytical results in literature. A series of cases with different initial entering velocities are simulated. The maximum force on the wedge and the corresponding time required to reach it for the different cases of initial entering velocities of the wedge are obained and fitted into formulas against the initial entering velocity of the wedge. The maximum drag coefficients of the wedge for the different cases with Froude number greater than 2 are all near the value of 0.91.

关键词： water entry Smoothed Particle Hydrodynamics (SPH) non-reflection boundary

CALCULATION OF ADDED MASS OF A VEHICLE RUNNING WITH CAVITY

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Journal of Hydrodynamics 2010年第3期22卷 312-318页

作者： LI Jie LU Chuan-jing HUANG Xuan department of Engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China department of Engineering Mechanics Shanghai Jiao Tong University Shanghai 200240 China State Key Laboratory of Ocean Engineering Shanghai Jiao Tong University Shanghai 200030 China

A numerical method is developed to obtain the added mass coefficients of a vehicle running with cavity in numerical simulation for the multiphase flow of the vehicle which is imposed an added vibration and analyzing its hydrodynamic loads. The method is verified through the cases of non-cavitating sphere and ellipsoid. The changing rule of the added mass of a sphere during water exit is gained. Then the influence of cavitation on the added mass of a cylinder is studied. The results show that λ 11, λ22, λ26, λ66 all decrease as the cavitation number reduces and the length of the attached cavity increases. There is almost a linear relationship between the cavity length and λ22 .The base cavity has great influence on λ11 its contribution decreases more than 60%, when the cavitation number changes from 0.6 to 0.2.

关键词： added mass cavity carrying forced vibration method

Data fusion for target tracking in wireless sensor networks using quantized innovations and Kalman filtering

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science china(Information sciences) 2012年第3期55卷 530-544页

作者： XU Jian1,2 , LI JianXun1,2 & XU Sheng3.1department of Automation, science and Technology on Avionics Integration Laboratory, shanghai jiao tong university, {3., china 2department of Automation, System Control and Information Processing, Ministry of Education of china, shanghai jiao tong university, {3., china 3.chool of Mechanical Engineering, shanghai jiao tong university, {3., china 1. department of Automation Science and Technology on Avionics Integration Laboratory Shanghai Jiao Tong University Shanghai 200240 China2. Department of Automation System Control and Information Processing Ministry of Education of China Shanghai Jiao Tong University Shanghai 200240 China3. School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China

A novel networked data-fusion method is developed for the target tracking in wireless sensor networks (WSNs). Specifically, this paper investigates data fusion scheme under the communication constraint between the fusion center and each sensor. Such a message constraint is motivated by the bandwidth limitation of the communication links, fusion center, and by the limited power budget of local sensors. In the proposed scheme, each sensor collects one noise-corrupted sample, performs a quantizing operation, and transmits quantized message to the fusion center. Then the fusion center combines the received quantized messages to produce a final estimate. The novel data-fusion method is based on the quantized measurement innovations and decentralized Kalman filtering (DKF) with feedback. For the proposed algorithm, the performance analysis of the estimation precision is provided. Finally, Monte Carlo simulations show the effectiveness of the proposed scheme.

关键词： data fusion target tracking limited bandwidth quantized innovation Kalman filtering

Seamlet carving for shape-aware image resizing

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science china(Information sciences) 2012年第5期55卷 1073-1081页

作者： LIN Xiao 1,2,SHENG Bin 1,MA LiZhuang 1,SHEN Yang 1 & CHEN ZhiHua 3.1 department of computer science and Engineering,{3.,shanghai 200240,china 2 Academy of Information Technology,Luoyang Normal university,Luoyang 471022,china 3.department of computer science and Engineering,East china university of science and Technology,shanghai 20023.,china 1. department of computer science and Engineering Shanghai Jiao Tong University Shanghai 200240 China2. Academy of Information Technology Luoyang Normal University Luoyang 471022 China3. Department of Computer Science and Engineering East China University of Science and Technology Shanghai 200237 China

In this paper we propose an optimized seam-carving approach for anti-shearing image *** image/video seam-carving strategy only focuses on deleting the pixels along 8-connected seams,which may lead to the obvious information loss during *** the traditional seam-carving methods,our approach can construct a seamlet to handle the discontinuous pixels and further achieve an optimized image resizing results with *** particular,to suppress zigzag artifacts,we introduce the anti-shearing energy into the seamlet generation,which includes two steps:1) the energy map is formalized by using Gabor filtering and the saliency map;2) The energy computation is optimized in Gabor feature space to obtain the resizing results without the connectivity *** experimental results and comparisons show the effectiveness of our method.

关键词： image resizing seamlet carving saliency map

Computational model for perception of objects and motions

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science china(Life sciences) 2008年第6期51卷 526-536页

作者： YANG WenLu1,2, ZHANG LiQing1 & MA LiBo1 1 department of computer science and Engineering, {3., shanghai 200240, china 2 department of Electronic Engineering, shanghai Maritime university, shanghai 20013., china 1. department of computer science and Engineering Shanghai Jiao Tong University Shanghai 200240 China 2. department of Electronic Engineering Shanghai Maritime University Shanghai 200135 China

Perception of objects and motions in the visual scene is one of the basic problems in the visual system. There exist 'What' and 'Where' pathways in the superior visual cortex, starting from the simple cells in the primary visual cortex. The former is able to perceive objects such as forms, color, and texture, and the latter perceives 'where', for example, velocity and direction of spatial movement of objects. This paper explores brain-like computational architectures of visual information processing. We propose a visual perceptual model and computational mechanism for training the perceptual model. The compu- tational model is a three-layer network. The first layer is the input layer which is used to receive the stimuli from natural environments. The second layer is designed for representing the internal neural information. The connections between the first layer and the second layer, called the receptive fields of neurons, are self-adaptively learned based on principle of sparse neural representation. To this end, we introduce Kullback-Leibler divergence as the measure of independence between neural responses and derive the learning algorithm based on minimizing the cost function. The proposed algorithm is applied to train the basis functions, namely receptive fields, which are localized, oriented, and bandpassed. The resultant receptive fields of neurons in the second layer have the characteristics resembling that of simple cells in the primary visual cortex. Based on these basis functions, we further construct the third layer for perception of what and where in the superior visual cortex. The proposed model is able to perceive objects and their motions with a high accuracy and strong robustness against additive noise. computer simulation results in the final section show the feasibility of the proposed perceptual model and high efficiency of the learning algorithm.

关键词： visual perception visual cortex computational model receptive fields simple cells complex cells