Hierarchies in nucleation transitions

We discuss the hierarchy of subphase transitions in first-order-like nucleation processes for an exemplified aggregation transition of heteropolymers. We perform an analysis of the microcanonical entropy, i.e., the density of states is considered as the central statistical system quantity since it connects system-specific entropic and energetic information in a natural and unique way.     

Evolutionary Approaches to Figure-Ground Separation

The problem of figure-ground separation is tackled from the perspective of combinatorial optimization. Previous attempts have used deterministic optimization techniques based on relaxation and gradient descent-based search, and stochastic optimization techniques based on simulated annealing and microcanonical annealing. A mathematical model encapsulating the figure-ground separation problem that makes explicit the definition of shape in terms of attributes such as cocircularity, smoothness, proximity and contrast is described. The model is based on the formulation of an energy function that incorporates pairwise interactions between local image features in the form of edgels and is shown to be isomorphic to the interacting spin (Ising) system from quantum physics. This paper explores a class of stochastic optimization techniques based on evolutionary algorithms for the problem of figure-ground separation. A class of hybrid evolutionary stochastic optimization algorithms based on a combination of evolutionary algorithms, simulated annealing and microcanonical annealing are shown to exhibit superior performance when compared to their purely evolutionary counterparts and to classical simulated annealing and microcanonical annealing algorithms. Experimental results on synthetic edgel maps and edgel maps derived from gray scale images are presented.     

Event-triggered-based finite-time cooperative path following control for underactuated multiple marine surface vehicles

This paper develops an event-triggered-based finite-time cooperative path following (CPF) control scheme for underactuated marine surface vehicles (MSVs) with model parameter uncertainties and unknown ocean disturbances. First, a finite-time extended state observer (FTESO) is proposed, in which the FTESO can estimate the velocities and compound disturbances in finite time. Then, the finite-time LOS guidance law based on velocity estimation values is designed to obtain the desired surge velocity and the desired yaw rate. In order to realize the cooperative control of multiple paths in finite time, the cooperative control law for the path variable is designed. In addition, the relative threshold event-triggered control (ETC) mechanism is incorporated into the formation control algorithm, and an event-triggered-based finite-time CPF controller is designed, which not only effectively reduces the update frequency of controller and the mechanical loss of actuator but also improves the control performance of system. Furthermore, by using homogeneous method, Lyapunov theory, and finite-time stability theory, it is proved that under the proposed finite-time CPF control scheme, the formation errors can converge to a small neighborhood around origin in finite time. Finally, numerical simulation results illustrate the effectiveness of the proposed control scheme.     

一种基于3APL的多agent合作系统*

提出了一种新的基于3APL的多agent合作系统.引入合作规划表达式给出基于扩展巴克斯范式(EBNF)个体agent的3APL语法.利用推理规则、结构结合变换规则等概念提出新的多agent合作操作语义.并深入研究多agent合作慎思循环过程,通过例子说明了多agent间如何合作产生和修正规划的过程.     

基于对象的扩展Petri网协同设计过程分析

针对协同设计中任务的执行流程缺乏柔性,不利于分析实际设计过程的现状,提出一种单元调用变迁对与决策变迁相集成的基于对象的扩展Petri网,扩展了Petri网的可达图以适应分析OEPNs模型.采用OEPNs中的过程网和单元阿对协同设计过程楚模,利用模型中的单元调用变迁对和决策变迁对过程本身和可能状态进行分析.最后与相关的研究工作进行比较并给出了结论.     

On the analysis of cooperation and antagonism in networks of communicating processes

We propose a new method for the analysis of cooperative and antagonistic properties of communicating finite state processes (FSPs). This algebraic technique is based on a composition operator and on the notion of possibility equivalence among FSPs. We demonstrate its utility by showing that potential blocking, termination, and lockout can be decided in polynomial time for loosely connected networks of tree FSPs. Potential blocking and termination are examples of cooperative properties, while lockout is an antagonistic one. For loosely connected networks of (the more general) acyclic FSPs, the cooperative properties become NP-complete and the antagonistic ones PSPACE-complete. For tightly coupled networks of tree FSPs, we also have NP-completeness for the cooperative properties. For the harder case of FSPs with cycles, we provide a natural extension of the method.     

含攻击角约束的网络化弹药分布式模糊协同制导律

在舰炮网络化弹药打击近岸机动目标的末制导段,提出了一种考虑攻击角约束的有限时间分布式模糊协同制导律.构建网络化弹药–目标相对运动模型,设计扩张状态观测器估计目标的切向、法向加速度.在视线切向,为保证命中时刻在有限时间内趋于一致,采用积分滑模设计分布式有限时间协同制导律;在视线法向,为在有限时间内零化视线角误差、视线角速率并改善控制指令终端发散现象,采用非奇异终端滑模设计两阶段制导律.为削弱控制指令抖振、补偿干扰,设计模糊自适应系统,并通过Lyapunov理论证明了全系统状态的一致最终有界性与有限时间收敛性.仿真实验表明:该制导律使网络化弹药在打击机动形式不同的目标时,均具备较好的协同制导性能.     

Strongly Subgame-Consistent Core in Stochastic Games

This paper investigates stochastic games on finite tree graphs. A given n-player normal-form game is defined at each node of a tree. Transition to a next node of the tree is random and depends on the strategy profile realized in a current game. We construct a cooperative solution of the game by maximizing the total expected payoff of the players. The core is used as the solution concept of the cooperative game. We introduce the definition of a strongly subgame-consistent (strongly time-consistent) core. Finally, we suggest a method for designing a cooperative distribution procedure of an imputation from the core that guarantees its strong subgame consistency.     

一种协同式安全事件处理系统

对事件响应进行了理论分析，给出了事件定义、事件分类、基于XML式的事件描述和交换格式、事件的生命周期和状态转换和事件响应的协同处理方式等一套完整的规范。针对大规模网络环境设计了一个协同式事件响应系统来实现网络安全事件的协同处理。并介绍了CIRS的系统结构及其组成部分。     

Finite‐time formation control of multiple nonholonomic mobile robots

This paper considers finite‐time formation control problem for a group of nonholonomic mobile robots. The desired formation trajectory is represented by a virtual dynamic leader whose states are available to only a subset of the followers and the followers have only local interaction. First of all, a continuous distributed finite‐time observer is proposed for each follower to estimate the leader's states in a finite time. Then, a continuous distributed cooperative finite‐time tracking control law is designed for each mobile robot. Rigorous proof shows that the group of mobile robots converge to the desired geometric formation pattern in finite time. At the same time, all the robots can track the desired formation trajectory in finite time. Simulation example illustrates the effectiveness of our method. Copyright © 2012 John Wiley & Sons, Ltd.     

有限时间内异构多智能体系统的协同输出调节

针对异构多智能体系统有限时间输出调节问题,本文提出了分布式有限时间状态观测器控制算法和相应的输出反馈控制策略.应用图论、Lyapunov稳定性理论证明了所设计的观测器能够在有限时间内估计出外部系统状态,同时可以保证系统在有限时间内的稳定性,很好的解决了当部分跟随者无法获取外部命令时的有限时间输出调节问题.最后,通过MATLAB数值仿真验证了该协议的有效性和正确性,仿真结果表明系统除了在有限时间内获得更快的收敛速度外,还具有良好的暂态性能.     

Semi-tensor product of matrices approach to reachability of finite automata with application to language recognition

This paper investigates the transition function and the reachability conditions of finite automata by using a semitensor product of matrices, which is a new powerful matrix analysis tool. The states and input symbols are first expressed in vector forms, then the transition function is described in an algebraic form. Using this algebraic representation, a sufficient and necessary condition of the reachability of any two states is proposed, based on which an algorithm is developed for discovering all the paths from one state to another. Furthermore, a mechanism is established to recognize the language acceptable by a finite automaton. Finally, illustrative examples show that the results/algorithms presented in this paper are suitable for both deterministic finite automata (DFA) and nondeterministic finite automata (NFA).     

Chromosome Reconstruction from Physical Maps Using a Cluster of Workstations

Ordering clones from a genomic library into physical maps of whole chromosomes presents a central computational problem in genetics. Chromosome reconstruction via clone ordering is shown to be isomorphic to the classical NP-complete Optimal Linear Arrangement problem. Parallel algorithms for simulated annealing and microcanonical annealing based on Markov chain decomposition are proposed and applied to the problem of chromosome reconstruction via clone ordering. These algorithms are implemented on a cluster of UNIX workstations using the Parallel Virtual Machine (PVM) system. PVM is a software system that permits a heterogeneous collection of networked computers to be viewed by a user's program as a single monolithic parallel computing resource. The parallel algorithms are implemented and tested on clonal data derived from Chromosome IV of the fungus Asperigillus nidulans Perturbation methods and problem-specific annealing heuristics for the parallel simulated annealing and parallel microcanonical annealing algorithms are proposed and described. Convergence, speedup and scalability characteristics of the various parallel algorithms are analyzed and discussed. This revised version was published online in June 2006 with corrections to the Cover Date.     

Figure-ground discrimination: a combinatorial optimization approach

The figure-ground discrimination problem is considered from a combinatorial optimization perspective. A mathematical model encoding the figure-ground discrimination problem that makes explicit a definition of shape based on cocircularity, smoothness, proximity, and contrast is presented. This model consists of building a cost function on the basis of image element interactions. This cost function fits the constraints of an interacting spin system that, in turn, is a well suited physical model that solves hard combinatorial optimization problems. Two combinatorial optimization methods for solving the figure-ground problem, namely mean field annealing, which combines mean field approximation theory and annealing, and microcanonical annealing, are discussed. Mean field annealing may be viewed as a deterministic approximation of stochastic methods such as simulated annealing. The theoretical bases of these methods are described, and the computational models are derived. The efficiencies of mean field annealing, simulated annealing, and microcanonical annealing algorithms are compared. Within the framework of such a comparison, the figure-ground problem may be viewed as a benchmark     

Cooperative Tasking for Deterministic Specification Automata

This paper proposes necessary and sufficient conditions for task decomposability with respect to an arbitrary finite number of agents. It is furthermore shown that fulfilling the decomposed local tasks by individual agents guarantees the satisfaction of the original global decomposable task. A divide‐and‐conquer approach for cooperative tasking among multi‐agent systems is proposed. The basic idea is to decompose an assigned global specification (given as a deterministic automaton) into subtasks for individual concurrent agents such that the fulfillment of these subtasks by each individual agent leads to the satisfaction of the global specification as a team. A cooperative scenario involving three robots has been implemented to illustrate the proposed technique. This work provides insights into what kinds of tasks can be achieved distributively, which helps designers specify achievable global tasks for a group of agents and design necessary information sharing among each other for a particular task.     

基于super-twisting算法的多航天器姿态有限时间分布式协同控制

针对受外界干扰和执行器故障影响的多航天器姿态协同控制问题,本文设计了一种基于干扰观测器的分布式协同supper-twisting滑模控制器.首先,将各航天器的外界干扰和执行器故障看作一个集总干扰,设计自适应滑模干扰观测器对其进行估计.其次,将supper-twisting算法和积分滑模面相结合,设计一种基于多航天器姿态...     

Complexity of evolution in maximum cooperative P systems

We introduce a variant of P systems called maximum cooperative P systems; it consists of transition P systems with cooperative rules that evolve at each step by consuming the maximum number of objects. The problem of distributing objects to rules in order to achieve a maximum consuming evolution is studied by introducing the resource mapping problem. The decision version of this optimization problem is proved to be NP-complete. We describe a new simulation technique for the evolution of the maximum cooperative P systems based on integer linear programming. Finally we illustrate the evolution by an example.     

On the analysis of cooperation and antagonism in networks of communicating processes

We propose a new method for the analysis of cooperative and antagonistic properties of communicating finite state processes (FSPs). This algebraic technique is based on a composition operator and on the notion of possibility equivalence among FSPs. We demonstrate its utility by showing that potential blocking, termination, and lockout can be decided in polynomial time for loosely connected networks of tree FSPs. Potential blocking and termination are examples of cooperative properties, while lockout is an antagonistic one. For loosely connected networks of (the more general) acyclic FSPs, the cooperative properties become NP-complete and the antagonistic ones PSPACE-complete. For tightly coupled networks of tree FSPs, we also have NP-completeness for the cooperative properties. For the harder case of FSPs with cycles, we provide a natural extension of the method.A preliminary version of this paper appeared as an extended abstract in theProceedings of the Fourth Annual ACM Symposium on Principles of Distributed Computing, August, 1985, pp. 23–38. P. C. Kanellakis was supported by ONR-DARPA Grant N00014-83-K-0146, NSF Grant DCR-8302391, and by the Office of Army Research under contract DAAG29-84-K-0058. S. A. Smolka was supported by National Science Foundation Grant DCR-8505873.     

<Emphasis FontCategory="SansSerif">VeriSiMPL</Emphasis> 2: An open-source software for the verification of max-plus-linear systems

This work presents a technique to generate finite abstractions of autonomous Max-Plus-Linear (MPL) systems, a class of discrete-event systems employed to characterize the dynamics of the timing related to the synchronization of successive events. Abstractions of MPL systems are derived as finite-state transition systems. A transition system is obtained first by partitioning the state space of the MPL system into finitely many regions and then by associating a unique state of the transition system to each partitioning region. Relations among the states of the transition system are then set up based on the underlying dynamical transitions between the corresponding partitioning regions of the MPL state space. In order to establish formal equivalences, the obtained finite abstractions are proven either to simulate or to bisimulate the original MPL system. The approach enables the study of general properties of the original MPL system formalized as logical specifications, by verifying them over the finite abstraction via model checking. The article presents a new, extended and improved implementation of a software tool (available online) for the discussed formal abstraction of MPL systems, and is tested on a numerical benchmark against a previous version.