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Communication network designing:Transmission capacity,cost and scalability

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science china(Information sciences) 2012年第11期55卷 2454-2465页

作者： ZHANG GuoQiang1,2,3 & ZHANG GuoQing1 1Institute of Computing technology,Chinese Academy of sciences,Beijing 100190,china 2school of computer science and technology,nanjing Normal university,nanjing 210046,china 3Provincial Key Laboratory for computer Information Processing technology,Soochow university,Suzhou 215000,china Institute of Computing technology Chinese Academy of Sciences Beijing China school of computer science and technology Nanjing Normal University Nanjing China Provincial Key Laboratory for computer Information Processing technology Soochow University Suzhou China

Despite the growing number of works centering around the traffic dynamics on complex networks,these researches still have some common shortcomings,e.g.,too simple traffic flow model and lack of considerations for the designing cost and scalability *** paper builds on a more realistic traffic flow model,and offers a holistic view on the network designing *** addition to the extensively studied transmission capacity,this paper takes designing cost and scalability as two other designing objectives,and presents a quantitative study of how different designing choices independently and collectively influence these objectives by the introduction of a cartesian coordinate *** is shown that different kinds of network topologies display different shapes of achievable solution spaces and exhibit different abilities to achieve cost-effective and scalable *** particular,we find the philosophy underlying empirical network designing and engineering today fails to meet the cost-effective and scalable designing requirements,and propose a cost-effective and scalable designing scheme for BA-like networks,i.e.,the efficient routing combined with effective betweenness based link bandwidth *** addition,when designing a thoroughly new network from the beginning,we find that ER network is a good candidate to achieve cost-effective and scalable designing in most settings.

关键词： cost-effective communication network designing network transmission efficiency network topology traffic dynamics next generation network scalable network designing

Technical framework for Internetware: An architecture centric approach

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science in china(Series F) 2008年第6期51卷 610-622页

作者： YANG FuQing1,2, Lü Jian3,4 & MEI Hong1,2 1 Key Laboratory of High Confidence Software Technologies (Peking university), Ministry of Education, Beijing 100871, china 2 school of Electronics Engineering and computer science, Peking university, Beijing 100871, china 3 State Key Laboratory for Novel Software technology, nanjing 210093, china 4 Department of computer science and technology, nanjing university, nanjing 210093, china Key Laboratory of High Confidence Software Technologies (Peking university) Ministry of Education Beijing China school of Electronics Engineering and computer science Peking University Beijing China State Key Laboratory for Novel Software technology Nanjing China Department of computer science and technology Nanjing University Nanjing China

Being a new software paradigm evolved by the Internet, Internetware brings many challenges to the traditional software methods and techniques. Sponsored by the national basic research program （973）, researchers in china have developed an architecture centric technical framework for the definition, incarnation and engineering of Internetware. First of all, a software model for Internetware is defined for what to be, including that Internetware entities should be packaged as components, behaving as agents, interoperating as services, collaborating in a structured and on demand manner, etc. Secondly, a middleware for Internetware is designed and implemented for how to be, including that Internetware entities are incarnated by runtime containers, structured collaborations are enabled by runtime software architecture, Internetware can be managed in a reflective and autonomic manner, etc. Thirdly, an engineering methodology for Internetware is proposed for how to do, including the way to develop Internetware entities and their collaborations by transforming and refining a set of software architectures which cover all the phases of software lifecycle, the way to identify and organize the disordered software assets by domain modeling, etc.

关键词： Internetware component software architecture agent middleware

A relative local variational principle for topological pressure

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science china Mathematics 2010年第6期53卷 1491-1506页

作者： MA XianFeng1,CHEN ErCai2,3,& ZHANG AiHua2,4 1Department of Mathematics,East china university of science and technology,Shanghai 200237,china 2school of Mathematics and computer science,nanjing Normal university,nanjing 210097,china 3Center of Nonlinear science,nanjing university,nanjing 210093,china 4College of Mathematics and Physics,nanjing university of Posts and Telecommunications,nanjing 210046,china Department of Mathematics East China University of Science and Technology Shanghai China school of Mathematics and computer science Nanjing Normal University Nanjing China Center of Nonlinear science Nanjing University Nanjing China College of Mathematics and Physics Nanjing University of Posts and Telecommunications Nanjing China

We define the relative local topological pressure for any given factor map and open cover,and prove the relative local variational principle of this *** precisely,for a given factor map π:(X,T)→(Y,S) between two topological dynamical systems,an open cover U of X,a continuous,real-valued function f on X and an S-invariant measure ν on Y,we show that the corresponding relative local pressure P(T,f,U,y) satisfies sup μ∈M(X,T){ hμ(T,U|Y)+∫X f(x)dμ(x) :πμ=ν}=∫Y P(T,f,U,y)dν(y),where M(X,T) denotes the family of all T-invariant measures on ***,the supremum can be attained by a T-invariant measure.

关键词： pressure conditional entropy relative local variational principle

A RELAXATION RESULT OF FUNCTIONALS IN THE SPACE SBD(Ω)

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Acta Mathematica Scientia 2008年第4期28卷 770-778页

作者：吕中学杨孝平 school of Mathematical science Xuzhou Normal University school of sciences Nanjing University of Science and Technology

In this article,the authors obtain an integral representation for the relaxation of the functionalF（x,u,Ω）：={∫^f（x,u（x）,εu（x））dx Ω if u∈W^1,1（Ω,R^N）, ＋∞ otherwise, in the space of functions of bounded deformation,with respect to L^*** Eu represents the absolutely continuous part of the symmetrized distributional derivative Eu.f（x,p,ξ）satisfying weak convexity assumption.

关键词： Integral representation relaxation special functions with bounded deformation

One-step estimation for varying coefficient models

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science china Mathematics 2005年第2期48卷 198-213页

作者： TANG Qingguo & WANG Jinde Department of Mathematics, nanjing university, nanjing 210093, china Institute of sciences, PLA university of science and technology, nanjing 210007, china Department of Mathematics Nanjing University Nanjing China Institute of sciences PLA University of Science and Technology Nanjing China

A one-step method is proposed to estimate the unknown functions in the varying coefficient models, in which the unknown functions admit different degrees of smoothness. In this method polynomials of different orders are used to approximate unknown functions with different degrees of smoothness. As only one minimization operation is employed, the required computation burden is much less than that required by the existing two-step estimation method. It is shown that the one-step estimators also achieve the optimal convergence rate. Moreover this property is obtained under conditions milder than that imposed in the two-step estimation method. More importantly, as only one minimization operation is employed, the full asymptotic properties, not only the asymptotic bias and variance, but also the asymptotic distributions of the estimators can be derived. The asymptotic distribution results will play a key role for making statistical inference.

关键词： varying coefficient model, one-step estimation, asymptotic distribution, optimal convergence rate.

Decentralized H-infinity state feedback control for discrete-time singular large-scale systems

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控制理论与应用（英文版） 2010年第2期8卷 200-204页

作者： Songlin WO 1 , Yun ZOU 2 , Shengyuan XU 2 (1.school of Electrical and Information Engineering, Jiangsu Teachers university of technology, Changzhou Jiangsu 213001, china 2.school of Automation, nanjing university of science and technology, nanjing Jiangsu 210094, china) school of Electrical and Information Engineering Jiangsu Teachers University of Technology Changzhou Jiangsu China school of Automation Nanjing University of Science and Technology Nanjing Jiangsu China

The decentralized H-infinity control problem for discrete-time singular large-scale systems is considered. Based on the bounded real lemma of discrete-time singular systems, a sufficient condition for the existence of decentralized H-infinity controller for discrete-time singular large-scale systems is presented in terms of the solvability to a certain system of linear matrix inequalities by linear matrix inequality (LMI) approach, and the feasible solutions to the system of LMIs provide a parameterized representation of a set of decentralized H-infinity controller. The given example shows the application of the method.

关键词： Discrete-time singular large-scale system Linear matrix inequality (LMI) Decentralized H-infinity control

Stability of a linear oscillator with damping force of the fractional-order derivative

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science china(Physics,Mechanics & Astronomy) 2010年第2期53卷 345-352页

作者： WANG ZaiHua1,2 & HU HaiYan1 1 Institute of Vibration Engineering Research,nanjing university of Aeronautics and Astronautics,nanjing 210016,china 2 Institute of science,PLA university of science and technology,nanjing 211101,china Institute of Vibration Engineering Research Nanjing University of Aeronautics and Astronautics Nanjing China Institute of science PLA University of Science and Technology Nanjing China

It begins with the study of damping representation of a linear vibration system of single degree of freedom (SDOF),from the view point of fractional calculus. By using the idea of stability switch,it shows that the linear term involving the fractional-order derivative of an order between 0 and 2 always acts as a damping force,so that the unique equilibrium is asymp-totically stable. Further,based on the idea of stability switch again,the paper proposes a scheme for determining the stable gain region of a linear vibration system under a fractional-order control. It shows that unlike the classical velocity feedback which can adjust the damping force only,a fractional-order feedback can adjust not only the damping force,but also the elastic re-storing force,and in addition,a fractional-order PDα control can either enlarge the stable gain region or narrow the stable gain region. For the dynamic systems described by integer-order derivatives,the asymptotical stability of an equilibrium is guaranteed if all characteristic roots stay in the open left half-plane,while for the systems with fractional-order derivatives,the asymptotical stability of an equilibrium is guaranteed if all characteristic roots stay within a sector in the complex plane. Analysis shows that the proposed method,based on the idea of stability switch,works effectively in the stability analysis of dynamical systems with fractional-order derivatives.

关键词： vibration system fractional-order derivative asymptotical stability stability switch

Microstructure and Properties of Mg-12Gd-3Y-0.5Zr Alloys Processed by ECAP and Extrusion

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Journal of Wuhan university of technology(Materials science) 2011年第6期26卷 1128-1132页

作者：朱荣 Department of Materials science and Engineering Nanjing University of Science and Technology

Equal channel angular pressing （ECAP） processing and conventional extrusion （Ex） were applied to the Mg-12Gd-3Y-0.5Zr （wt%） magnesium alloy in order to evaluate the potential improvement in the mechanical properties. The ECAP experiment was conducted at 380 ℃ in a die having an included angle of 90° between two channels by the Bc route with the billet rotated by 90° about its longitudinal axis. Subsequently, some billets were processed by conventional extrusion at 300 ℃. The microstructures were examined by X-ray diffraction （XRD）, optical microscopy and transmission electron microscopy （TEM）. The experimental results indicate that the grain size is refined effectively, but the basal planes are highly inclined （about 40o） from the extrusion axis introduced by ECAP, which impairs the grain boundary strengthening effect. The conventional extrusion, following the ECAP, can modify the grains in hard orientation. Based on grain boundary strengthening due to ECAP and texture strengthening due to Ex, the strength is improved effectively. The enhanced activity of the non-basal slips, due to the refined grains and the reduction in c/a ratio, is responsible for good ductility and high strain hardening rate in samples obtained by the two-step process.

关键词： magnesium alloy equal channel angular pressing thermomechanical processing texture

Delayed Hopf bifurcation in time-delayed slow-fast systems

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science china(Technological sciences) 2010年第3期53卷 656-663页

作者： ZHENG YuanGuang1 & WANG ZaiHua1,2 1 Institute of Vibration Engineering Research,nanjing university of Aeronautics and Astronautics,nanjing 210016,china 2 Institute of science,PLA university of science and technology,nanjing 211101,china Institute of Vibration Engineering Research Nanjing University of Aeronautics and Astronautics Nanjing China Institute of science PLA University of Science and Technology Nanjing China

This paper presents an investigation on the phenomenon of delayed bifurcation in time-delayed slow-fast differential *** the two delayed's have different *** delayed bifurcation means that the bifurcation does not happen immediately at the bifurcation point as the bifurcation parameter passes through some bifurcation point,but at some other point which is above the bifurcation point by an obvious *** a time-delayed system,the evolution of the system depends not only on the present state but also on past *** this paper,the time-delayed slow-fast system is firstly simplified to a slow-fast system without time delay by means of the center manifold reduction,and then the so-called entry-exit function is defined to characterize the delayed bifurcation on the basis of Neishtadt's *** shows that delayed Hopf bifurcation exists in time-delayed slow-fast systems,and the theoretical prediction on the exit-point is in good agreement with the numerical calculation,as illustrated in the two illustrative examples.

关键词： time delay delayed bifurcation Hopf bifurcation slow-fast systems exit-point entry-exit function