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Aeroservoelastic model based active control for large civil aircraft

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science china(Technological sciences) 2010年第4期53卷 1126-1137页

作者： FAN Yong1,ZHU JiHong1,HU ChunHua2,MENG XianYu1,WANG XiangYang2 & GE AiXue1 1 Department of computer science and technology,Tsinghua university,beijing 100084,china 2 school of Astronautics and Aeronautics,Tsinghua university,beijing 100084,china 1. Department of computer science and technology Tsinghua University Beijing 100084 China2. School of Astronautics and Aeronautics Tsinghua University Beijing 100084 China

A modeling and control approach for an advanced configured large civil aircraft with aeroservoelasticity via the LQG method and control allocation is *** models and implementation issues for the multi-input/multi-output(MIMO) aeroservoelastic system simulation developed for a flexible wing with multi control surfaces are described.A fuzzy logic based optimization approach is employed to solve the constrained control allocation problem via intelligently adjusting the components of output vector and find a proper vector in the attainable moment set(AMS) *** basic idea is to minimize the L2 norm of error between the desired moment and achievable moment using the designing freedom provided by redundantly allocated actuators and control *** the constraints of control surfaces,in order to obtain acceptable performance of aircraft such as stability and maneuverability,the fuzzy weights are updated by the learning algorithm,which makes the closed-loop system ***,an application example of flight control designing for the advanced civil aircraft is discussed as a *** studies we have performed showed that the advanced configured large civil aircraft has good performance with the proper designed control law designed via the proposed *** gust alleviation and flutter suppression are applied with the synergetic effects of elevator,ailerons,equivalent rudders and *** results show good closed loop performance and meet the requirement of constraint of control surfaces.

关键词： modeling active control aeroelastic flutter suppression control allocation

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R-calculus without the cut rule

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science china(Information sciences) 2011年第12期54卷 2550-2563页

作者： LUO Jie & LI Wei State Key Laboratory of Software Development Environment, school of computer science and engineering, Beihang university, beijing 100191, china 1. State Key Laboratory of Software Development Environment School of Computer Science and Engineering Beihang University Beijing 100191 China

R-calculus is an inference system for deducing all possible changes when a theory is refuted by the facts. In this paper, we try to eliminate the cut rule in R-calculus by modifying the existing rules and by introducing new rules. The result is the R-calculus without the cut rule, which still preserves the reachability, soundness and completeness as R-calculus does. R-calculus without the cut rule is a formal inference system of logical connective symbols and quantifier symbols solely. It can serve as the theoretical foundation of the automation of revision calculus.

关键词： revision R-calculus cut rule

P2P traffic optimization

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science china(Information sciences) 2012年第7期55卷 1475-1492页

作者： ZHANG GuoQiang 1,2 ,TANG MingDong 3 ,CHENG SuQi 2,4 ,ZHANG GuoQing 2 ,SONG HaiBin 5 ,CAO JiGuang 6 & YANG Jing 7 1 school of computer science and technology,Nanjing Normal university,Nanjing 210046,china 2 Institute of Computing technology,Chinese Academy of sciences,beijing 100190,china 3 school of computer science and engineering,Hunan university of science and technology,Xiangtan 411201,china 4 Graduate university of Chinese Academy of sciences,beijing 100190,china 5 Nanjing R&D Center,Huawei Technologies,Nanjing 210012,china 6 china Academy of Telecommunication Research of MIIT,beijing 100191,china 7 china Mobile Research Institute,beijing 100053,china 1. school of computer science and technology Nanjing Normal University Nanjing 210046 China2. Institute of Computing Technology Chinese Academy of Sciences Beijing 100190 China3. School of Computer Science and Engineering Hunan University of Science and Technology Xiangtan 411201 China4. Graduate University of Chinese Academy of Sciences Beijing 100190 China5. Nanjing R&D Center Huawei Technologies Nanjing 210012 China6. China Academy of Telecommunication Research of MIIT Beijing 100191 China7. China Mobile Research Institute Beijing 100053 China

Peer-to-peer (P2P) based content distribution systems have emerged as the main form for content distribution on the Internet,which can greatly reduce the distribution cost of content providers and improve the overall system ***,the mismatch between the overlay and underlay networks causes large volume of redundant traffic,which intensifies the tension between P2P content providers and ***,how to efficiently use network resources to reduce the traffic burden on the ISPs is crucial for the sustainable development of P2P *** paper surveys the state-of-art P2P traffic optimization technologies from three perspectives:P2P cache,locality-awareness and data *** details,comparison between these technologies and their applicabilities are presented,followed by a discussion of the issues that remain to be addressed and the direction of future content distribution research.

关键词： P2P traffic localization P2P traffic optimization P2P cache locality-awareness network coding content-centric network

Video motion stitching using trajectory and position similarities

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science china(Information sciences) 2012年第3期55卷 600-614页

作者： CHEN XiaoWu, LI Qing , LI Xin & ZHAO QinPing State Key Laboratory of Virtual Reality technology and Systems, school of computer science and engineering, Beihang university, beijing 100191, china 1. State Key Laboratory of Virtual Reality technology and Systems School of Computer Science and Engineering Beihang University Beijing 100191 China

Stitching motions in multiple videos into a single video scene is a challenging task in current video fusion and mosaicing research and film production. In this paper, we present a novel method of video motion stitching based on the similarities of trajectory and position of foreground objects. First, multiple video sequences are registered in a common reference frame, whereby we estimate the static and dynamic backgrounds, with the former responsible for distinguishing the foreground from the background and the static region from the dynamic region, and the latter functioning in mosaicing the warped input video sequences into a panoramic video. Accordingly, the motion similarity is calculated by reference to trajectory and position similarity, whereby the corresponding motion parts are extracted from multiple video sequences. Finally, using the corresponding motion parts, the foregrounds of different videos and dynamic backgrounds are fused into a single video scene through Poisson editing, with the motions involved being stitched together. Our major contributions are a framework of multiple video mosaicing based on motion similarity and a method of calculating motion similarity from the trajectory similarity and the position similarity. Experiments on everyday videos show that the agreement of trajectory and position similarities with the real motion similarity plays a decisive role in determining whether two motions can be stitched. We acquire satisfactory results for motion stitching and video mosaicing.

关键词： video fusion video mosaicing video registration background estimation motion stitching

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Lp shape deformation

science china(Information sciences) 2012年第5期55卷 983-993页

作者： GAO Lin1,ZHANG GuoXin 1 & LAI YuKun 2 1 Department of computer science and technology,Tsinghua university,beijing 100084,china 2 school of computer science and Informatics,Cardiff university,Wales CF24 3AA,UK 1. Department of computer science and technology Tsinghua University Beijing 100084 China2. School of Computer Science and Informatics Cardiff University Wales CF24 3AA UK

Shape deformation is a fundamental tool in geometric *** methods consider preserving local details by minimizing some energy functional measuring local distortions in the L 2 *** strategy distributes distortions quite uniformly to all the vertices and penalizes ***,there is no unique answer for a natural deformation as it depends on the nature of the *** by recent sparse signal reconstruction work with non L 2 norm,we introduce general L p norms to shape deformation;the positive parameter p provides the user with a flexible control over the distribution of unavoidable *** with the traditional L 2 norm,using smaller p,distortions tend to be distributed to a sparse set of vertices,typically in feature regions,thus making most areas less distorted and structures better *** the other hand,using larger p tends to distribute distortions more evenly across the whole *** flexibility is often desirable as it mimics objects made up with different *** specifying varying p over the shape,more flexible control can be *** demonstrate the effectiveness of the proposed algorithm with various examples.

关键词： shape deformation Lp norm geometric modeling

Online approach to feature interaction problems in middleware based system

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science in china(Series F) 2008年第3期51卷 225-239页

作者： HUANG Gang1,2 LIU XuanZhe1,2 & MEI Hong1,2 1 Key Laboratory of High Confidence Software Technologies, Ministry of Education, Peking university, beijing 1000871, china 2 school of Electronics engineering and computer science, Peking university, beijing 100871, china Key Laboratory of High Confidence Software Technologies Ministry of Education Peking University Beijing 1000871 China school of Electronics engineering computer science Peking University Beijing 100871 China

As a popular infrastructure for distributed systems running on the Internet, middleware has to support much more diverse and complex interactions for coping with the drastically increasing demand on information technology and the extremely open and dynamic nature of the Internet. These supporting mechanisms facilitate the development, deployment, and integration of distributed systems, as well as increase the occasions for distributed systems to interact in an undesired way. The undesired interactions may cause serious problems, such as quality violation, function loss, and even system crash. In this paper, the problem is studied from the perspective of the feature interaction problem （FIP） in telecom, and an online approach to the detection and solution on runtime systems is proposed. Based on a classification of middleware enabled interactions, the existence of FIP in middleware based systems is illustrated by four real cases and a conceptual comparison between middleware based systems and telecom systems. After that, runtime software architecture is employed to facilitate the online detection and solution of FIP. The approach is demonstrated on J2EE （Java 2 Platform Enterprise Edition） and applied to detect and resolve all of the four real cases.

关键词： feature interaction middleware reflective software architecture

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An architecture for mobile database management system

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Journal of university of science and technology beijing 2002年第2期9卷 156-160页

作者： Dong Li and Yucai Feng computer school, Huazhong university of science and technology, Wuhan 430074, china computer school Huazhong University of Science and Technology Wuhan 430074 China

In order to design a new kind of mobile database management system (DBMS)more suitable for mobile computing than the existent DBMS, the essence of database systems in mobilecomputing is analyzed. An opinion is introduced that the mobile database is a kind of dynamicdistributed database, and the concept of virtual servers to translate the clients' mobility to theservers' mobility is proposed. Based on these opinions, a kind of architecture of mobile DBMS, whichis of versatility, is presented. The architecture is composed of a virtual server and a local DBMS,the virtual server is the kernel of the architecture and its functions are described. Eventually,the server kernel of a mobile DBMS prototype is illustrated.

关键词： mobile database dynamic distributed database DBMS architecture virtual server data region

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Selection of unitary operations in quantum secret sharing without entanglement

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science china(Information sciences) 2011年第9期54卷 1837-1842页

作者： XU Juan 1,CHEN HanWu 1,LIU WenJie 1,2 & LIU ZhiHao 1 1 school of computer science and engineering,Southeast university,Nanjing 210096,china 2 school of computer and Software,Nanjing university of Information science and technology,Nanjing 210044,china 1. school of computer science and engineering Southeast University Nanjing 210096 China2. School of Computer and Software Nanjing University of Information Science and Technology Nanjing 210044 China

We propose a substitute-Bell-state attack strategy for quantum secret sharing schemes without entanglement,as well as a definition of the minimum failure probability of such attack strategy.A quantitative analysis of security degrees corresponding to different unitary operations is also provided,when the secret sharing schemes without entanglement are stricken by substitute-Bell-state *** a result,the relation between the selection of unitary operations and the effect of substitute-Bell-state attack is shown,which can serve as an important guidance for the selection of unitary operations in designing and implementing quantum secret sharing schemes.

关键词： quantum secret sharing substitute-Bell-state attack unitary operation minimum failure probability

Prediction of Dynamic Wellbore Pressure in Gasified Fluid Drilling

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Petroleum science 2007年第4期4卷 66-73页

作者： Wang Zhiming1,Ping Liqiu2 and Zou Ke2 (1. school of Petroleum engineering,Petroleum university of china,beijing 102249,china) (2. Institute of Drilling engineering technology,CNPC,beijing 100097,china) Petr Univ china Sch Petr Engn Beijing 102249 Peoples R China CNPC Inst Drilling Engn Technol Beijing 100097 Peoples R China

The basis of designing gasified drilling is to understand the behavior of gas/liquid two-phase flow in the wellbore. The equations of mass and momentum conservation and equation of fluid flow in porous media were used to establish a dynamic model to predict wellbore pressure according to the study results of Ansari and Beggs-Brill on gas-liquid two-phase flow. The dynamic model was solved by the finite difference approach combined with the mechanistic steady state model. The mechanistic dynamic model was numerically implemented into a FORTRAN 90 computer program and could simulate the coupled flow of fluid in wellbore and reservoir. The dynamic model revealed the effects of wellhead back pressure and injection rate of gas/liquid on bottomhole pressure. The model was validated against full-scale experimental data,and its 5.0% of average relative error could satisfy the accuracy requirements in engineering design.

关键词： Gasified fluid drilling dynamic model pressure prediction model validation