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In this paper, Petri nets technique is introduced into mobile ad hoc networks (MANET) and a packet-flow parallel scheduling scheme is presented using Stochastic Petri Nets (SPN). The flowing of tokens is used in graphics mode to characterize dynamical features of sharing a single wireless channel. Through SPN reachability analysis and isomorphic continuous time Markov process equations, some network parameters, such as channel efficiency and, one-hop transmission delay, can be obtained. Compared with Those of The conventional performance evaluation methods, the above parameters are mathematical expressions instead of test results from simulator. 相似文献
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结合目前国产数控相贯线切割机普遍配备双倾角构型割炬的技术特点,对传统管材切割工艺进行了改进.通过对传统切割工艺中的几何近似部分进行精确几何建模,获得精确几何解,并通过双旋转自由度构型的割炬,完成基于该精确几何解的切割角精确切割.仿真实验表明:相对于传统的近似切割工艺,该切割角精确切割工艺可有效减少管件端面的有效切割长度,提高了切割速度和时间效率,且切割出的管材端面更符合曲面的几何性质,有利于焊接面之间的曲面匹配度. 相似文献
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随着形式化方法和技术的日趋完善,网络协议的开发已逐步从非形式化描述、手工方法实现过渡到已形式化描述技术为基础,渗透到网络协议分析、综合、测试等各环节的软件工程方法。本文从网络协议的基本要素、协议的形式化模型介绍了网络协议,并从协议的性质描述、不变性分析、可达性分析、基于有序二叉判决图的符号模型检验对网络协议进行了形式化设计与验证,最后进行了测试。 相似文献
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浅谈排球扣球教学中助跑与起跳技术 总被引:1,自引:0,他引:1
扣球是排球的基本技术之一,也是排球中攻击性最强的一项技术,在比赛中占有十分重要的地位。扣球是得分的主要手段,也是取胜的关键。在扣球的教学中助跑与起跳的衔接是重要的一个环节!是否掌握正确的助跑步伐,是否有效的衔接起跳显得尤为重要!在此基础上才能使进攻更富有变化和威胁。 相似文献
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Research infrastructure is crucial for development of research,and thus the evaluation of its performance is important.However,existing researches mostly focus on its past observations,lacking of a prediction for future. In this paper, procedures are proposed to predict the distribution for the number of papers published in a certain future year. The publication reliability,which is defined as the probability that the number of published papers in the future year is bigger than a pre-specified number,is evaluated. Illustrative examples are proposed to show the applications of the model. 相似文献
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研究了SOA 有源光开关原理与光开关矩阵的基本构成,给出了相关的主要性能参数,包括开关速度、消光比、噪声指数、动态范围以及开关增益等,实际制备了一个有源光开关基本单元矩阵,并给出初步实验结果 相似文献
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The research infrastructure is very crucial for the development of some fundamental research. However,it is costly to buy,install and operate the infrastructure. This paper analyzes the costs and benefits of research infrastructure using a concept termed as investment reliability. Both the costs and the outputs are represented by a cash flow diagram,and the investment reliability is modeled. Different types of outputs are taken into concern in the model formulation. Illustrative examples are proposed to show how to apply the model. 相似文献