关于取绝对值的函数可微性的讨论

求绝对值函数的导数是高等数学的一个难点。本文证明了一个公式,能较全面地解决绝对值函数的求导问题。     

一种齿轮箱振动控制方法

从机械结构的振动控制理论出发 ,提出了一种齿轮箱振动控制方法 ,研究并讨论几种齿轮箱箱体以及齿轮本体的结构参数对动态特性的影响 ,其结论可以为齿轮箱的振动设计提供参考依据     

载流管道在基础振动下的振动控制

根据舰船管道的实际情况 ,在载流管系的动态响应分析中引入基础振动的影响 .计算分析了舰船管道系统在流体激励、外部干扰力和基础振动情况下的动态响应 .研究了如何减小基础振动对管路系统振动的影响 ,通过计算分析 ,提出了比较有效的减振措施 .     

自适应数据库应用系统的开发方法与实现

在数据库应用系统开发过程中 ,往往需要考虑系统的自适应性。介绍用PowerBuilder实现动态修改表结构、数据处理界面和打印表格格式的方法 ,从而达到使系统具有自适应性的目的。     

用于动平衡测试的MDAC窄带跟踪滤波器

为了从强干扰噪声中提取出与转速同频的振动分量,且适应转速波动时的情形,利用互相关原理导出了跟踪滤波方法,并采用乘法数模转换器(MDAC)设计并实现了窄带跟踪滤波器。实验结果表明,其增益相对误差优于0.2%,相位绝对误差优于0.4°,当转速变化率不超过9000r/min2时,滤波器的输出能够跟踪转速的变化。该滤波器能较好地满足动平衡测试的需要。     

Scheduling stochastic jobs with asymmetric earliness and tardiness penalties

We consider a stochastic counterpart of the well-known earliness-tardiness scheduling problem with a common due date, in which n stochastic jobs are to be processed on a single machine. The processing times of the jobs are independent and normally distributed random variables with known means and known variances that are proportional to the means. The due dates of the jobs are random variables following a common probability distribution. The objective is to minimize the expectation of a weighted combination of the earliness penalty, the tardiness penalty, and the flow-time penalty. One of our main results is that an optimal sequence for the problem must be V-shaped with respect to the mean processing times. Other characterizations of the optimal solution are also established. Two algorithms are proposed, which can generate optimal or near-optimal solutions in pseudopolynomial time. The proposed algorithms are also extended to problems where processing times do not satisfy the assumption in the model above, and are evaluated when processing times follow different probability distributions, including general normal (without the proportional relation between variances and means), uniform, Laplace, and exponential. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44, 531–557, 1997.     

分布式虚拟环境中环境信息动态更新研究

环境信息动态更新是分布式虚拟环境的一个主要特点,如何使环境信息更新更活跃、更反应实际情况,一直是分布式虚拟环境研究的重点。在典型的分布式交互环境中,环境信息动态更新是基于协议数据单元(PDU),它不提供数据可靠性传输保证。如何保证分布式环境中各结点环境信息一致性,本文提出了一种信息校验和协议,它通过极少的信息传输就可保证各结点环境信息高度一致。文中定义了保证分布式环境信息动态一致性更新的协议数据单元,并在试验环境中证明了协议的可靠性。     

空陆攻防博弈的动态武器目标分配

大规模作战具有高动态、非完全信息和不确定性,在分析归纳目前解决动态武器目标分配问题的一系列方法的基础上,尝试构建基于双方动态博弈的攻防对抗综合数学模型,并利用纳什均衡和帕累托最优算法进行分阶段求解。结果表明,该数学模型和博弈论方法结合能够有效解决武器目标动态分配问题。     

备件保障效能动态评估方法

针对目前效能评估方法多重视效能指标的静态观测值,对时序状态数据所蕴含的趋势信息关注较少的缺点,提出基于灰色聚类-粗糙集和集对分析的备件保障效能动态评估方法。针对主客观赋权方法各自的优缺点,引入依赖度和重要度的概念,建立灰色聚类-粗糙集组合赋权模型;将指标权重引入集对理论,提出集对同势、均势和反势的定义,描述备件保障效能的变化规律,构建基于马尔可夫链的集对分析动态模型。实例分析结果表明,该方法可以有效反映备件保障效能的动态变化特征,为决策者制定备件保障长期计划提供科学依据。     

Shortest path interdiction problem with arc improvement recourse: A multiobjective approach

We consider the shortest path interdiction problem involving two agents, a leader and a follower, playing a Stackelberg game. The leader seeks to maximize the follower's minimum costs by interdicting certain arcs, thus increasing the travel time of those arcs. The follower may improve the network after the interdiction by lowering the costs of some arcs, subject to a cardinality budget restriction on arc improvements. The leader and the follower are both aware of all problem data, with the exception that the leader is unaware of the follower's improvement budget. The effectiveness of an interdiction action is given by the length of a shortest path after arc costs are adjusted by both the interdiction and improvement. We propose a multiobjective optimization model for this problem, with each objective corresponding to a different possible improvement budget value. We provide mathematical optimization techniques to generate a complete set of strategies that are Pareto‐optimal. Additionally, for the special case of series‐parallel graphs, we provide a dynamic‐programming algorithm for generating all Pareto‐optimal solutions.