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11.
建立正确、有效的任务模型是正确引导出信息系统需求的关键步骤。文中针对任务间时序依赖关系,给出与任务建模相关的若干形式定义和命题,帮助分析人员判断任务间的并发和死锁。给出任务间时序依赖关系建模的详细步骤,并根据时序依赖关系的传递性质,给出一种任务关系图上的传递闭包方法,可以帮助分析人员直观地判断任务间时序依赖关系的问题和错误,科学、合理地标记各个任务的时序等级属性,帮助建模人员从全局上明确各个任务在执行时所处的相对位置,以及在每个阶段需要同时展开哪些任务。  相似文献   
12.
We consider the scheduling of large‐scale projects to maximize the project net present value given temporal and resource constraints. The net present value objective emphasizes the financial aspects of project management. Temporal constraints between the start times of activities make it possible to handle practical problem assumptions. Scarce resources are an expression of rising cost. Since optimization techniques are not expedient to solve such problems and most heuristic methods known from literature cannot deal with general temporal constraints, we propose a new bidirectional priority‐rule based method. Scheduling activities with positive cash flows as early and activities with negative cash flows as late as possible results in a method which is completed by unscheduling techniques to cope with scarce resources. In a computational experiment, we compare the well‐known serial generation scheme where all activities are scheduled as early as possible with the proposed bidirectional approach. On the basis of a comprehensive data set known from literature containing instances with up to 1002 activities, the efficiency of the new approach is demonstrated. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2003  相似文献   
13.
Command and Control (C2) in a military setting can be epitomized in battles‐of‐old when commanders would seek high ground to gain superior spatial‐temporal information; from this vantage point, decisions were made and relayed to units in the field. Although the fundamentals remain, technology has changed the practice of C2; for example, enemy units may be observed remotely, with instruments of varying positional accuracy. A basic problem in C2 is the ability to track an enemy object in the battlespace and to forecast its future position; the (extended) Kalman filter provides a straightforward solution. The problem changes fundamentally if one assumes that the moving object is headed for an (unknown) location, or waypoint. This article is concerned with the new problem of estimation of such a waypoint, for which we use Bayesian statistical prediction. The computational burden is greater than an ad hoc regression‐based estimate, which we also develop, but the Bayesian approach has a big advantage in that it yields both a predictor and a measure of its variability. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004  相似文献   
14.
本文综述了致伤因素对目标的致伤效果,取决于击中的部位和释放能量的多少,且随着击中部位和因素的改变而不同。指出各因素对目标的致伤作用既有相互影响又有其独立性。并给出了致伤因素对目标综合效应的估算公式。  相似文献   
15.
时态逻辑形式化描述并发系统性质   总被引:1,自引:0,他引:1  
时态逻辑是一种描述反应式(并发)系统中状态迁移序列的形式化方法,用于刻画并发系统所需验证的性质,是模型检测的基础.阐述了时态逻辑CTL 及其子逻辑CTL、LTL的语法及语义,然后分析运用时态逻辑描述并发系统性质,最后给出一个应用实例.  相似文献   
16.
用形式化规范语言Z定义了多A gen t协作模型的基本元素,包括:A gen t、目标、角色、交互协议和过程,给出了应满足的一致性约束,并通过城市区域的连锁超市物流调度系统说明了该形式化规范为多A gen t协作提供了一致性和连贯性。  相似文献   
17.
Earlier research on the effects of nonoverlapping temporal aggregation on demand forecasting showed the benefits associated with such an approach under a stationary AR(1) or MA(1) processes for decision making conducted at the disaggregate level. The first objective of this note is to extend those important results by considering a more general underlying demand process. The second objective is to assess the conditions under which aggregation may be a preferable approach for improving decision making at the aggregate level as well. We confirm the validity of previous results under more general conditions, and we show the increased benefit resulting from forecasting by temporal aggregation at lower frequency time units. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 489–500, 2014  相似文献   
18.
非形式化/半形式化模型到形式化模型之间的转换是当前软件工程领域的研究热点。根据异构模型转换,提出了基于MDA的MARTE模型到Object-Z规约之间的转换方法。针对Object-Z在实时领域表达能力不足的问题,首先扩展Object-Z元模型;然后在MDA的元元模型体系下,定义了MARTE元模型和扩展的Object-Z元模型之间的转换规则。MARTE模型可以重用这些转换规则以实现到Object-Z形式化描述之间的转换,进而可以对模型进行形式化验证;最后通过一个实例使用该方法完成模型转换,具体说明了转换规则的应用。  相似文献   
19.
对战场目标战术意图的快速、准确和自动识别,是智能决策的前提和基础。目标战术意图通常由多个战术动作组合完成,因而目标状态呈现动态、时序变化特征。本文针对目标意图识别问题的特点,提出一种基于栈式自编码器( SAE)的智能识别模型,设计智能识别模型的基本框架,提出一种基于时序特征的输入信号编码方法及相应的模式解析机制,通过将目标状态在多个时刻的时序特征和战场环境、目标属性等信息统一编码为输入信号,将军事专家的知识经验封装为模式标签,模拟人的推理模式与认知经验,实现对目标战术意图的智能识别。最后通过实验,分析预训练过程和网络深度对算法性能的影响,并通过与多层感知机(MLP)和逻辑回归分类器(LRC)识别准确率的比较,验证所提SAE算法的有效性。  相似文献   
20.
本文从信号处理设备对输入信号进行时域和频域数字信号处理的角度,论述了采用抗混滤波器进行抗混滤波的必要性.经论证提出了抗混滤波器的设计指标,进行了切比雪夫抗混滤波器的设计计算.最后对实现的抗混滤波器进行了性能测试,取得了满意结果.  相似文献   
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