HLA/RTI中的时间管理机制分析

RTI是HLA的核心，时间管理服务作为RTI提供的六大类服务之一，按照HLA接口规范说明来管理各类消息的发送和接收，并协调不同的时间推进机制，以保证分布式仿真的逻辑正确性。详细描述了HLA／RTI的时间管理机制。     

基于HLA的潜艇作战仿真系统时间管理研究

时间管理服务是运行支撑系统(run-time infrastructure,RTI)提供的6类服务之一,它按照高层体系结构接口规范来管理各类消息的发送和接收,并协调不同的时间推进机制,以保证分布式仿真的逻辑正确性.针对仿真驱动的潜艇实装作战仿真训练系统,结合HLA时间管理常见问题,从开发基于HLA仿真应用的角度分析了时间管理机制,重点研究了潜艇作战仿真训练系统中的推演时间管理方法.     

基于CORBA的HLA/RTI时间管理的实现

时间管理是HLA／RTI中重要的服务之一，时间管理服务的目的是保证RTI能在适当的时间以适当的方式和顺序将来自盟员的消息转发给相应的盟员，主要包括时间较准约束机制，逻辑时间推进和相关时间请求3部分，HLA时间管理由RTI和盟员共同完成，RTI提供相应的接口，以实现有效信息交换，该文提出了一个基于CORBA的时间管理实现方案。     

关于HLA中时间推进机制的研究

时间管理是HLA接口规范中重要的一类服务,它管理各类消息的发送和接收并协调不同的时间推进机制,以确保分布仿真的逻辑正确性。文章对时间推进机制进行了研究,并给出了乐观时间推进机制的实现方法。     

一种无死锁的时间管理算法

高层体系结构HLA(high level architecture)是美国国防部提出的建模和仿真的标准,时间管理服务是其重要的组成部分,而GALT(greatest available logical time)的计算是RTI(runtime infrastructure)时间管理服务实现的核心技术.GALT算法容易导致死锁,继而导致整个仿真无法推进.在Frederick Kuhl算法的基础上探讨了死锁产生时系统所特有的一些规律,得出了一些重要结论:如果系统处于死锁状态,则所有盟员的GALT和输出时间一定分别相等,并且GALT一定等于输出时间;所有Lookahead大于0的盟员一定处于NMR/NMRA推进状态而不会处于其他推进状态(TAR/TARA/FQR).最后提出了基于"身高测量法"的无死锁的GALT算法,"身高测量法"为RTI中时间管理模块的实现提供了可靠保证.     

基于MOM的HLA/RTI管理盟员的设计与实现

为了在仿真运行过程中对联盟、盟员以及RTI进行监控，HLA中引入了管理对象模型(MOM)，该模型是HLA／RTI架构中的重要组成部分。该文介绍了IEEEl516规范中定义的MOM，并在此基础上对其进行了扩展。结合我们StarLink RTI的开发实践，提出了通过代理盟员实现MOM的设计方案，在该RTI中实现了对MOM的支持。最后在此基础上，设计并实现了管理盟员StarFM。     

基于同步和异步时间管理的混合时间管理算法

基于HLA的并行分布式仿真是目前仿真的一种趋势.HLA的接口规范中定义了六类服务,其中时间管理服务是保证联邦成员之间正确交互的基础.时间管理服务保证了在仿真过程中所发生的事件在逻辑上的正确性,以及所发送的消息在逻辑上的有序性.实现该管理机制有两种方法:保守时间推进算法和乐观时间推进算法.而保守时间推进又可以通过异步时间管理算法或同步时间管理算法来实现,异步和同步算法各有优缺点,这使得它们的运用具有一定的局限性.文中全面分析了异步和同步时间管理算法的优缺点,在此基础上提出了一种将两者结合,进行优缺点互补的混合时间管理算法,以此来提高保守时间推进算法的效率,使其能更好地运用于RTI中.并通过实验验证了该混合算法的有效性.     

一种基于历史的DDM实现方法

DDM是HLA接口规范中定义的六大服务之一。它允许盟员声明其在路由空间中的更新区域和定购区域,从而达到减少HLA盟员间数据交换量的目的。它是RTI服务实现效率的关键,其核心问题是如何减少需要匹配的区域,以减少计算量。文章简要介绍了现有的几种方法,并分析了其各自的特点,在此基础上提出了一种基于历史的DDM方法。     

基于HLA时间管理的仿真程序实现

论文就HLA/RTI的时间管理服务,从仿真程序设计者的角度出发,介绍了HLA中诸如事件、消息、时间、时戳和消息顺序等概念,针对保守的时间推进机制的推进策略、推进原则以及推进原语进行了阐述。最后,文章较为详细地探讨了基于时间推进的仿真程序框架,以及程序的执行流程。     

基于桥接盟员的异类RTI和多联盟互连技术研究

高层体系结构(high level architecture,HLA)的互操作模式基于单一的联盟执行上下文,并未涉及不同RTI(run-time infrastructure)和联盟间的互操作及联盟级的互操作和重用 .提出一种基于桥接盟员的异类RTI和多联盟的互连体系结构,据此设计实现了RTIBridge桥接软件,详细介绍其软件结构以及其中的关键技术问题,分析了桥接盟员执行RTI服务的典型流程,提出一种异类RTI和多联盟互连开发和执行过程模型,最后进行了实验与结果分析 .     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Call for Papers The 6^th International Conference on Grid and Cooperative Computing

Recent years have seen rapid advances in various grid-related technologies, middleware, and applications. The GCC conference has become one of the largest scientific events worldwide in grid and cooperative computing. The 6th international conference on grid and cooperative computing (GCC2007) Sponsored by China Computer Federation (CCF),Institute of Computing Technology, Chinese Academy of Sciences (ICT) and Xinjiang University ,and in Cooperation with IEEE Computer Soceity ,is to be held from August 16 to 18, 2007 in Urumchi, Xinjiang, China.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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