HLA_ACTOR_REPAST: An approach to distributing RePast models for high-performance simulations

RePast is a popular agent toolkit with proven capabilities to fulfil the modelling challenges of large multi-agent systems (MASs). The toolkit, though, is normally used on a standalone workstation and therefore its practical use can be constrained (in space and time) by the limited available computing resources. This paper proposes an original approach – HLA_ACTOR_REPAST – aimed to distributing RePast models for high-performance simulation of complex scalable models. Novel in HLA_ACTOR_REPAST is an exploitation of a lean actor infrastructure implemented in Java. Actors bring to RePast agents such features as migration, location-transparent naming, efficient communications, and a control-centric framework. Actors can be orchestrated by an in-the-large custom control structure which is in charge of ensuring the necessary message causality constraints. Distribution and time management concerns depend on the IEEE standard HLA middleware. The paper first discusses details of the software engineering process underlying the development of HLA_ACTOR_REPAST. The mapping techniques, assisted by Java text annotations and aspect-oriented programming, try to minimize “code intrusions” in the original model and favour model transparency. The paper then furnishes some experimental data which witness the good performance results achieved by applying HLA_ACTOR_REPAST to a distributed version of a classic MAS benchmark model.     

基于HLA的卫星分布仿真系统设计与实现

基于HLA(高层体系结构)规范，利用自主版权的AST-RTI(运行时间框架)软件，设计并实现了具有开放性、可扩展性、稳定性的卫星分布仿真系统。该系统完成了卫星侦察、通讯的过程仿真以及数据处理评估。解决了一系列关键技术，如时钟同步、大数据量信息传输、第3方软件集成、仿真Agent技术等。     

基于HLA的卫星通信链路分布式仿真的研究

该文首先对HLA进行了概述。其次介绍了卫星通信链路仿真系统的功能,该功能是由10个模型构成的基础模块和应用模块实现的;在此基础上提出了一种基于HLA的卫星通信链路分布式仿真系统的设计框架,构建了由11个联邦成员组成的卫星通信链路仿真联邦,并较为详细地阐述了仿真系统的联邦成员的设计和联邦成员间信息交互的设计,给出了联邦成员间信息传递关系的示意图,较好地解决了仿真系统各功能模型的同步、并行运行的问题;最后通过仿真得出了有关结论,为卫星通信链路、通信网络的设计与性能评估奠定了基础。     

基于多物品拍卖的网格映射算法设计与模拟

由于网格底层资源的异构、广域分布、自治等特性和网格高层的服务质量 (QoS)要求,使得网格资源映射算法的设计和模拟具有相当的难度。提出了基于多物品拍卖的网格资源映射算法,解决了网格系统中相互独立任务模式的资源映射问题。同时对比了当前的网格资源映射模拟工具,阐述了利用GridSim建立基于多物品拍卖的资源映射算法模拟平台的主要步骤。最后模拟实验表明此算法具有优良性能。     

协同软件开发工具集综述

该文在分析协同软件开发工具的需求和关键技术的基础上,介绍并讨论了一些协同软件的研究状况和国外的系统、研究趋势,力图在高度概括的基础上对每个研究的热点给予一定的介绍和剖析。对国外系统的介绍中突出了各个系统的特点和优点,形成了一定的比较。     

Event‐Triggered Iterative Learning Control for Multi‐Agent Systems with Quantization

The emergence of networked control systems urges the digital control design to integrate communication constraints efficiently. In order to accommodate this requirement, this paper investigates the joint design of tracking problem for multi‐agent system (MAS) in the presence of resource‐limited communication channel and quantization. An event‐triggered robust learning control with quantization is firstly proposed and employed for MAS in this paper. The new event‐triggered distributed robust learning control system with the introduction of logarithmic quantization guarantees the asymptotic tracking property on the finite interval. Convergence analysis is given based on the Lyapunov direct method. Finally, numerical simulations are given to illustrate the efficacy of the event‐triggered approach compared with time‐triggered controllers.     

高层体系结构与多智能体仿真集成研究

对于复杂大系统的建模与仿真,多智能体系统可以提供并行逻辑的支持,而高层体系结构(HLA)则可以提供公共的技术框架.两者的结合能有效地提高系统仿真与建模的效果,但是HLA/RTI的规范对多智能体系统的灵活性与开放性有一定的限制,不能充分发挥智能体在推理交互和协商合作等高层次通信方面的优秀特性.在高层体系结构下利用JADE平台工具对多智能体仿真环境进行了研究,提出了集成系统的总体架构和具体方法,并建立了原型系统,通过实验验证了集成方案的可行性,为进一步的研究奠定了基础.     

基于STKX和HLA的空天仿真系统研究

在运用STK与HLA进行分布式空天仿真时缺少应用集成框架。为此,提出基于STKX和HLA的空天仿真系统。研制支持可变参数,且覆盖所有CONNECT命令的STKX适配器,对基本RTI进行面向对象封装,以实现包括运行库与辅助支持工具的HLA适配器,运用两级适配器搭建系统集成框架,并将其投入应用。结果表明,该框架能简化调用流程,提高执行效率。     

基于Agent的Repast仿真分析与实现

基于复杂适应系统(CAS)理论在计算机上建立模型是研究社会复杂系统的一个基本方法.选择一个合适的基于A-gent的建模与仿真平台能降低社会科学工作者的研究难度.Repast是目前使用较多的基于Agent的建模与仿真平台之一,主要应用于社会科学仿真领域.简要介绍了Repast平台的背景,从建模与仿真的两个角度分析了Repast仿真的特点,并介绍了Repast的主要类库.从仿真实现的基本步骤,Repast内含的时间表机制和显示机制,仿真程序框架几方面探讨了Repast仿真模型的设计与实现流程.从CarryDrop模型的实现结果,能看出基于Repast平台能较方便地实现基于Agent的仿真.最后指出Repast平台突出的特点是能充分利用.Net和Java类库的众多功能.     

大型分布式仿真环境下的负载平衡策略

在大型分布式仿真环境下,仿真的顺利推进取决于每一个邦员的健康运行,负载不平衡会对仿真性能造成严重的影响。作为分布式仿真事实上的标准,HLA仿真框架主要关注于解决分布式仿真的互操作和可重用问题,而没有提供对可伸缩性、动态负载平衡以及容错的支持。通过分析HLA仿真框架的不足,提出了一个基于网格服务的先进分布式仿真框架GADS,并在此基础上设计了一个负载平衡解决方案,随后重点描述了其中的负载平衡策略和基于仿真代理的高效邦员迁移算法。利用在GADS框架中引入的仿真代理层,该迁移方案大大降低了迁移开销,并实现了真正的“免冻结”迁移。     

Revisiting conservative time synchronization protocols in parallel and distributed simulation

Computer simulations have become an indispensable tool for the empirical study of large‐scale systems. The timely simulation of these systems, however, is not without its challenges. Simulators have to be able to harness the full computational power of modern multicore architectures through parallel execution and overcome the memory limitations of a single computer. In this paper, we evaluate the performance of a parallel and distributed simulator using several conventional time synchronization protocols executed on modern multicore hardware. In addition, we comprehensively analyze a hybrid approach, combining two traditional protocols, increasing robustness, and enabling improved performance in a wider range of simulation scenarios. Finally, an adaptive algorithm to automatically configure this hybrid protocol is introduced and evaluated, eliminating manual user intervention and further improving robustness with respect to varying simulation conditions. Copyright © 2013 John Wiley & Sons, Ltd.     

HLA与MAS在分布式仿真领域的应用比较

高层体系结构(HLA)和多Agent系统(MAS)是目前分布式仿真领域的两个研究热点。两者适用性如何,各方面有何异同之处,在具体的仿真应用中如何来选择这两个不同的系统构架来作为技术路线,了解这两种不同技术的特点和它们之间的差异性是首要前提。该文通过介绍HLA和MAS在个体结构、通信和模型建立等各方面的优势和不足,系统地比较了它们之间的性能差异。结果表明两者都是分布式仿真应用的优选方案,HLA侧重资源重用,MAS更具自主性,需要根据具体仿真应用的要求来选择。     

基于HLA的多agent虚拟环境表现机制

高层体系结构（HLA）是美国国防部提出的新一代仿真技术框架,它具有高度的互操作性和可重用性。为大规模、分布式的具有复杂交互行为的多agent虚拟环境提供了良好的底层框架。本文针对基于HLA／RTI规范的多agent虚拟战场环境（MAVE－HLA）,提出了基于层次结构的动态实体的多媒体表现框架和相应的行为表现机制,它支持可重用、可扩展,同时实时性和交互性易于实现。     

Modeling and simulating software acquisition process architectures

In this paper, we describe our efforts to support the modeling and simulation of processes associated with software system acquisition activities. Software acquisition is generally a multi-organization endeavor concerned with the funding, management, engineering, system integration, deployment and long-term support of large software systems. We first describe our approach supporting the modeling and simulation of software acquisition processes using a software process architecture (SPA). We then introduce how we support the distribution, concurrent execution and interoperation of multiple software process simulations using the high-level architecture (HLA) and run-time infrastructure (RTI) to address the complexity of software acquisition process architectures. To illustrate this, we provide examples from the design and prototyping of a Web-based environment that supports the modeling and simulation of acquisition process architectures. This environment thus serves as a new kind of software process test-bed that can demonstrate and support experiments incorporating multiple software process simulation systems that interoperate in a distributed and concurrent manner across a network.     

复杂机械产品多Agent协同仿真研究

协同仿真是协同设计过程中的重要组成部分,成为检验、指导和优化设计的重要手段。车辆动力系统是一种典型的复杂机械产品。文章为解决协同仿真中复杂的交互通信问题,以动力系统为例,应用多Agent技术,研究复杂机械产品多Agent协同仿真的模型和方法。在分析了动力系统协同仿真的业务需求的基础上,提出了一种适合动力系统协同仿真的多Agent结构模型,Agent之间的通信方式采用KQML/XML,并以曲轴的静力学分析为例说明实现方法。     

iJob: an Internet-based job execution environment using asynchronous messaging

Various toolkits exist today for the distributed execution of computational algorithms on clusters of machines. These toolkits are often referred to by the terms ‘Grid Toolkits’, ‘Job Execution Environments’, and ‘Problem Solving Environments (PSEs)’. Here, we introduce iJob—an Internet-based job execution environment that sets out to meet many of the goals of PSEs, such as providing facilities and services to solve a class of problems. In addition, the iJob software allows execution of computational algorithms utilizing standard Internet technologies such as Java, XML, and asynchronous communication protocols. The goals of this project include: (1) deploying the toolkit easily to multiple platforms using the Java technologies; (2) running multiple types of algorithms and supporting multiple users simultaneously; (3) providing a web-based GUI for monitoring and controlling the status of jobs; and (4) providing security at both the user-level and at the network-level. The toolkit has been tested using several simulation codes on pools of Windows 2000 and Solaris systems.     

Average Consensus for Multi‐Agent System with Measurement Noise and Binary‐Valued Communication

This paper considers the average consensus problems of a class of multi‐agent systems (MAS) with binary‐valued communication. Each agent can only obtain its neighbor's binary‐valued information under measurement noise because of limited bandwidth in communication channels. To seek consensus, we propose a two‐scale multi‐agent consensus algorithm with distributed strategy by combining state estimation and control design alternately. An exponential step size is chosen in the state estimation process and the estimation method can be proved to be asymptotically efficient. Additionally, by utilizing a distributed control law designed based on the estimates of the neighbors' states with a constant gain, we further prove that the proposed average consensus algorithm is convergent. Furthermore, the proposed average consensus algorithm is given and proved. Finally, some simulation results, which illustrate the effectiveness of the obtained results, are also given in the paper.     

Toolkit design for interactive structured graphics

Here, we analyze toolkit designs for building graphical applications with rich user interfaces, comparing polylithic and monolithic toolkit-based solutions. Polylithic toolkits encourage extension by composition and follow a design philosophy similar to 3D scene graphs supported by toolkits including JavaSD and Openlnventor. Monolithic toolkits, on the other hand, encourage extension by inheritance, and are more akin to 2D graphical user interface toolkits such as Swing or MFC. We describe Jazz (a polylithic toolkit) and Piccolo (a monolithic toolkit), each of which we built to support interactive 2D structured graphics applications in general, and zoomable user interface applications in particular. We examine the trade offs of each approach in terms of performance, memory requirements, and programmability. We conclude that a polylithic approach is most suitable for toolkit builders, visual design software where code is automatically generated, and application builders where there is much customization of the toolkit. Correspondingly, we find that monolithic approaches appear to be best for application builders where there is not much customization of the toolkit.     

具有迁移能力的基于Agent分布仿真中的通信系统

对基于Agent系统的分布仿真是仿真领域的重要研究和应用方向，而分布仿真中的通信系统是其中的基础部分．提出并实现了一种支持基于Agent系统分布仿真的通信系统．该系统除了提供基本的仿真通信支持外，还能够有效地支持仿真中Agent的迁移，具有对应用系统透明、通信效率高等优点．首先给出了通信系统的结构及其基本思想，对局部服务Agent和通信过程进行了详细的描述；从应用系统级和分布仿真级两个层次，给出了结构化的通信协议；在此基础之上，给出了完整的Agent迁移支持方案，包括迁移过程、迁移过程中的消息处理和迁移后的通信；最后对通信系统的性能进行了测试．     

Extending process automation systems with multi-agent techniques

This paper presents a design of a process automation system extended with multi-agent systems (MAS) and experiments with its implementation. According to this design, MAS can be used to extend the functionality of ordinary process automation systems at higher levels of control. Anticipated benefits of this include enhanced reconfigurability, responsiveness and flexibility of the resulting automation system. The design also takes into account particular characteristics of process automation. An agent platform for process automation is presented as a basis for applying MAS. A FIPA-compliant agent platform is extended with process automation specific functionality. The platform utilizes a hierarchical agent organization and a BDI-agent model. Two applications are implemented using the platform. One of these shows how the techniques of distributed planning can be applied in discrete control. The other provides a model for supervisory continuous control using the techniques of distributed search. Experiments performed with a laboratory test environment using the applications are presented. They are able to demonstrate the feasibility of the approach in test scenarios.