| 摘要: |
| 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. |
| 关键词: 高层体系结构 时间管理 GALT 死锁 身高测量法 |
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| 基金项目:Supported by the National High-Tech Research and Development Plan of China under Grant No.2001AA115127 (国家高技术研究发展计划(863)); the National Grand Fundamental Research 973 Program of China under Grant No.G1999032703 (国家重点基础研究发展规划(973)) |
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| A Non-Deadlock Time Management Algorithm |
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LIU Bu-Quan,WANG Huai-Min,YAO Yi-Ping
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| Abstract: |
| HLA (high level architecture) is the standard for modeling and simulation put forward by the American Department of Defense. Time management is an important component of HLA while GALT (greatest available logical time) algorithm is RTI (runtime infrastructure)抯 critical technology in implementing time management. An improper GALT algorithm can easily result in a deadlock so that the whole federation can not advance any more. On the basis of the GALT algorithm introduced by Frederick Kuhl, the principles of deadlock are discussed and some important results are revealed in this paper. If deadlock occurs in a simulation, all federates must have the same GALT and the same output time respectively, and GALT is also equal to output time, and a federate whoselookahead is greater than zero must suspend because of a NMR or NMRA request, other than a TAR, TARA or FQR request. Finally, a GALT algorithm without deadlock is also brought forward in this paper that is calledStature-Measuring, and this algorithm can provide reliable technology support to develop time management services of RTI. |
| Key words: high level architecture time management GALT deadlock stature-measuring |
