基于堆排序的PQ+CBWFQ路由器排队调度算法

研究具有QoS特征、易于实现的排队算法一直是优化带宽的重要手段,也是提高宽带IP网络性能的主要途径。文章提出基于堆排序的PQ＋CBWFQ网络路由器排队调度算法进行具体实现,并给出低成本的硬件实现方案,对未来的高性能路由器设计具有重要的参考价值。     

Collaboration Through the Exploitation of Local Interactions in Autonomous Collective Robotics: The Stick Pulling Experiment

This article presents an experiment which investigates how collaboration in a group of simple reactive robots can be obtained through the exploitation of local interactions. A test-bed experiment is proposed in which the task of the robots is to pull sticks out of the ground—an action which requires the collaboration of two robots to be successful. The experiment is implemented in a physical setup composed of groups of 2 to 6 Khepera robots, and in Webots, a 3D simulator of Khepera robots.The results using these two implementations are compared with the predictions of a probabilistic modeling methodology (A. Martinoli, A. Ijspeert, and F. Mondada, 1999, Robotics and Autonomous Systems, 29:51–63, 1999; A. Martinoli, A. Ijspeert, and L. Gambardella, 1999, in Proceedings of Fifth European Conference on Artificial Life, ECAL99, Lecture Notes in Computer Science, Springer Verlag: Berlin, pp. 575–584) which is here extended for the characterization and the prediction of a collaborative manipulation experiment. Instead of computing trajectories and sensory information, the probabilistic model represents the collaboration dynamics as a set of stochastic events based on simple geometrical considerations. It is shown that the probabilistic model qualitatively and quantitatively predicts the collaboration dynamics. It is significantly faster than a traditional sensor-based simulator such as Webots, and its minimal set of parameters allows the experimenter to better identify the effect of characteristics of individual robots on the team performance.Using these three implementations (the real robots, Webots and the probabilistic model), we make a quantitative investigation of the influence of the number of workers (i.e., robots) and of the primary parameter of the robots' controller—the gripping time parameter—on the collaboration rate, i.e., the number of sticks successfully taken out of the ground over time. It is found that the experiment presents two significantly different dynamics depending on the ratio between the amount of work (the number of sticks) and the number of robots, and that there is a super-linear increase of the collaboration rate with the number of robots. Furthermore, we investigate the usefulness of heterogeneity in the controllers' parameters and of a simple signalling scheme among the robots. Results show that, compared to homogeneous groups of robots without communication, heterogeneity and signalling can significantly increase the collaboration rate when there are fewer robots than sticks, while presenting a less noticeable or even negative effect otherwise.     

基于风险的供需网契约协调仿真研究

针对供需网的一个典型节点, 研究随机需求情形下零售商主导的供需网契约协调问题。考虑由一个风险厌恶的零售商和一个风险厌恶的制造商构成的两层供需系统, 零售商制定最优批发价, 制造商决定最优供货量, 构建了基于收益共享费用共担的供需网协调模型。仿真分析结果表明, 当整个供需系统的风险厌恶系数高于制造商和零售商的风险厌恶系数时, 收益共享费用共担契约可以实现系统的显著改善甚至完美协调。     

协同办公系统在企业中的设计与应用

协同办公是现代企业管理模式的高级阶段, 研究人员从典型协同办公系统在企业中的技术路线规划和系统搭建入手, 对企业现有的业务流程管理进行优化和电子化, 在分段应用的基础上逐步提高协同办公系统在企业中的应用水平, 最后给出详细分析和应用展望.     

Two Case Studies of Semantics Execution in Maude: CCS and LOTOS

We explore the features of rewriting logic and, in particular, of the rewriting logic language Maude as a logical and semantic framework for representing and executing inference systems. In order to illustrate the general ideas we consider two substantial case studies. In the first one, we represent both the semantics of Milner’s CCS and a modal logic for describing local capabilities of CCS processes. Although a rewriting logic representation of the CCS semantics is already known, it cannot be directly executed in the default interpreter of Maude. Moreover, it cannot be used to answer questions such as which are the successors of a process after performing an action, which is used to define the semantics of Hennessy-Milner modal logic. Basically, the problems are the existence of new variables in the righthand side of the rewrite rules and the nondeterministic application of the semantic rules, inherent to CCS. We show how these problems can be solved in a general, not CCS dependent way by controlling the rewriting process by means of reflection. This executable specification plus the reflective control of rewriting can be used to analyze CCS processes. The same techniques are also used to implement a symbolic semantics for LOTOS in our second case study. The good properties of Maude as a metalanguage allow us to implement a whole formal tool where LOTOS specifications without restrictions in their data types (given as ACT ONE specifications) can be executed. In summary, we present Maude as an executable semantic framework by providing easy-tool-building techniques for a language given its operational semantics.Research supported by CICYT projects Desarrollo Formal de Sistemas Distribuidos (TIC97-0669-C03-01) and Desarrollo Formal de Sistemas Basados en Agentes Móviles (TIC2000-0701-C02-01).     

JSP实现基于中值排序基数法的BBS树状结构

用JSP实现基于中值排序基数法的BBS树状结构,给出数据结构的设计以及具体的算法实现。     

试论DEB协调控制指令限制逻辑的重要性

本文从DEB协调控制系统中锅炉主指令信号运算原理入手,对实际运行中影响信号安全运行的主要因素和指令运算限制逻辑的设计情况展开分析,阐述提高指令可靠性的改进对策和加强指令限制逻辑的调试、维护、管理的重要性.     

Interval Generalization of the Bayesian Model of Collective Decision-Making in Conflict Situations

A constructive interval model of making a collective decision by an independent group of experts is developed. The model is based on a priori information about the frequency of experts' errors in estimating a random state of an object using a finite sample. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 133–144, May–June 2005.     

多Agent系统合作与协调机制研究综述

多Agent间的合作和协调机制是多Agent系统理论的核心问题之一。本文按照协调在合作过程中发生的位置进行分类讨论,结合实例阐述了经典的多Agent系统合作与协调机制的主要原理、适用范围,旨在分析总结现有的多Agent合作和协调机制,为未来的开放、异构、动态环境下多Agent合作与协调机制的发展趋势和进一步研究的方向提供参考。     

有向网络下仿射非线性多个体协同动力学系统的整体行为

本文讨论有向通讯网络条件下仿射非线性多个体动力学系统的结构及其整体行为．系统可以分解为独立基本子系统和非独立基本子系统．每个独立基本子系统将趋于自身的一致状态,非独立子系统的个体状态将趋于独立基本子系统一致状态为顶点的凸集内．系统所有个体的状态趋于一致的充分必要条件是存在唯一的独立基本子系统．这一结果涵盖了线性多个体动力学系统此前的研究结果．     

复杂网络特性对大规模多智能体协同控制的影响

随着分布式多智能体系统应用领域和系统规模的不断扩大,网络特性已成为影响系统性能的一个重要因素.通过研究和分析复杂网络特性对大规模分布式多智能体系统协同控制的影响,对多智能体系统性能的影响做出系统性分析,同时为提出大规模多智能体组织结构的优化算法提供依据.主要针对随机网络、小世界网络、网格网络和无尺度网络这4种典型复杂网络特性,从理论和仿真两方面进行分析.在理论方面,通过基于马尔可夫链的信息传输过程在不同网络结构下的建模,对比分析了信息无偏随机游走模型和智能决策模型下的传输效率.在仿真建模中,主要从智能体间信息传输效率、不同应用领域中集成协同控制效率、对网络故障恢复的影响这3个典型的多智能体系统协同控制应用对比分析复杂网络特性对系统性能的影响.研究结果表明,复杂网络特性如小世界和无尺度特性可以在相同的控制策略下形成明显的性能差异,如果设计合理的控制算法,复杂网络结构将有助于多智能体系统性能的提升.     

Modern Information Infrastructure in the Support of Distributed Collective Practice in Transport

Transport is one of the oldest and most important forms of distributed collective practice. This paper traces the role of information and communication technologies in the transformation of transport-based distributed collective practice, focusing on the evolution of technologies that place control of the transport infrastructure in the hands of end users. Examples of this shift are provided, including an analysis of the events of September 11, 2001 as forms of distributed collective action.     

Collective agility,paradox and organizational improvisation: the development of a particle physics grid

This paper examines systems development in a global collaborative community of high‐energy physics and offers insights and implications for agile systems development in other large scale and distributed settings. The paper studies the ongoing construction of the UK's computing grid for particle physics (GridPP), a grid that is itself part of the world's largest grid, the Large Hadron Collider Computing Grid. We observe in this project a collective, agile and distributed performance through which the Grid is constructed. We express this through the concept of ‘collective agility’ which captures a large distributed performance rather than the more conventional sense of agility as small‐group and deliberate systems development practices. The collective agility of GridPP is analysed as a process of ‘enacted emergence’ expressed through the dynamics of six improvisation paradoxes.     

分布式信息系统中构件计算协调模型的研究-一种求解大型分布式信息系统中特征干扰的方法

介绍了一种利用分布式构件的计算协调模型来解决大型分布式信息系统中特征干扰的方法，并结合具体的分布式信息系统分析了系统中可能存在的各种构件计算关系，研究了分布式构件计算的协调问题，研究了具体的解决方案．     

鱼类群体运动的元胞自动机模型中的最小势能原理

群体运动是自然界中一种常见的生物行为. 在一定的环境条件下, 社会有机体会表现出不同的集体运动形态. 其中, 旋转是鱼群中常见的群体运动. 但是, 虽然研究人员对鱼群的运动进行过一系列的研究, 这种旋转行为的机理尚不清楚. 本研究假定鱼群的运动模式受势能的支配, 相应提出了鱼类个体运动的势函数并将之融合到元胞自动机中以模拟鱼群的运动. 数值模拟表明, 有限空间内鱼群运动时会形成多种形状, 但当此生物系统按照能量最小原则发展时, 其运动形态最终可能演化成为一个漩涡. 数值模拟与针对红斑马鱼的观察之间的比较验证了本模型的合理性. 能量最小原理是自然界的基本定律之一, 而势能函数的建立定义了鱼类个体与环境之间的关系. 因此, 本研究为深入理解群体运动规律提供了新视角, 表明从流体力学上进一步探究鱼群运动的物理机理是一个具有潜力的研究方向.     

Evaluating the CMM Level 3 KPA of Intergroup Coordination: A theory-based approach

This paper examines the Intergroup Coordination key process area (KPA) for theoretical significance and measurability. The Software Engineering Institute (SEI) has developed a framework called the Capability Maturity Model (CMM) which enables organizations to measure their “maturity” in doing software engineering. The CMM is not theoretically derived. It is, however, a result of years of anecdotal evidence collected from practitioners. This paper compares the Intergroup Coordination KPA to the body of literature on coordination and measures it using theoretically derived determinants. These determinants are then evaluated for possible relationships to productivity factors that indicate business process support. This revised version was published online in July 2006 with corrections to the Cover Date.     

Applying an Agent-Oriented Methodology to the Design of Artificial Organizations: A Case Study in Robotic Soccer

The multi-agent paradigm is widely used to provide solutions to a number of organizational problems related to the collective achievement of one or more tasks. All these problems share a common difficulty of design: how to proceed from the global specification of a collective task to the specification of the local behaviors to be provided to the agents? We have defined the Cassiopeia method whose specificity is to articulate the design of a multi-agent system around the notion of organization. This paper reports the use of this method for designing and implementing the organization of a soccer-playing robotic team. We show why we chose this application and how we designed it, and we discuss its interest and inherent difficulties in order to clearly express the needs for a design methodology dedicated to DAI.     

基于Linux操作系统的仿真应用

在有别于Windows操作系统下广泛使用的Matlab仿真软件和昂贵的大型专业仿真软件的基础上,给出了一个基于Linux操作系统的模型直升机仿真程序。结合Lin-ux操作系统的特点,探索在Linux下面编写仿真应用程序的一些值得注意的问题,包括图形化界面编程和进程间通信等一些热门技术。希望对Linux爱好者和程序员有所启发。     

Service contracts: Coordination of user-adaptation in Open Service Architectures

An Open Service Architecture (OSA) is a framework that supports an open set of users to subscribe to, and possibly pay for an open set of services. Today, the World Wide Web (WWW) is the most successful example of an OSA. Nevertheless, the WWW provides poor support for personalised services, since services cannot collaborate unless handcrafted to do so. We present a framework that allows independent, personalised services to coordinate their adaptations to individual users. The framework is described in terms of service contracts in an agent architecture. We first describe the general notion of service contracts, and then the particulars of service contracts used for adaptation coordination. Adaptation coordination addresses a crucial issue for OSAs: that of providing users with homogeneous interaction with heterogeneous services. We suggest that this is done by introducing a separate adaptation coordination agent, which orchestrates how the individual services are personalised.     

Meetings of the Board: The Impact of Scheduling Medium on Long Term Group Coordination in Software Development

Despite a wealth of electronic group tools for coordinating the software development process, instead we find technologically adept groups preferring to use what seem to be outmoded material tools in critical projects. The current ethnographic study investigates this apparent paradox. We begin by building up a detailed picture of the overall software development process and identify critical general problems in achieving coordination. Coordination problems arise in software development not only because of the complex dependencies that hold among the work of different individuals, but also for social and motivational reasons. We identify the central role of the schedule as a coordination device, but find that its value can be undermined because the schedule is often neither accurate, current nor credible. As a result, the schedule is not used as a resource for individual or group planning. We then compare coordination in two development groups, one using electronic and the other material scheduling tools. We found that the medium of the schedule has a major impact on coordination problems. The size, public location and physical qualities of material tools engender certain crucial group processes that current electronic technologies fail to support. A large wallboard located in a public area encouraged greater responsibility, commitment and updating and its material properties served to encourage more reflective planning. As a result the wallboard schedule was both accurate and current. Furthermore, the public nature of the wallboard promoted group interaction around the board, it enabled collaborative problem solving, as well as informing individuals about the local and global progress of the project. Despite these benefits, however, the material tool fell short on several other dimensions such as distribution, complex dependency tracking, and versioning. We make design recommendations about how the benefits of material tools could be incorporated into electronic groupware systems and discuss the theoretical implications of this work.