Application of Markov renewal theory and semi-Markov decision processes in maintenance modeling and optimization of multi-unit systems

In this paper, a condition-based maintenance model for a multi-unit production system is proposed and analyzed using Markov renewal theory. The units of the system are subject to gradual deterioration, and the gradual deterioration process of each unit is described by a three-state continuous time homogeneous Markov chain with two working states and a failure state. The production rate of the system is influenced by the deterioration process and the demand is constant. The states of the units are observable through regular inspections and the decision to perform maintenance depends on the number of units in each state. The objective is to obtain the steady-state characteristics and the formula for the long-run average cost for the controlled system. The optimal policy is obtained using a dynamic programming algorithm. The result is validated using a semi-Markov decision process formulation and the policy iteration algorithm. Moreover, an analytical expression is obtained for the calculation of the mean time to initiate maintenance using the first passage time theory.     

基于循环子空间理论的线性系统测试矩阵优化

研究了线性定常系统在循环指数大于1(即其约当标准形不同的约当块有重根)的情况下测试矩阵的优化方法.以循环子空间相关定理的证明为基础,根据根向量链的相关特性,得到了测试向量的线性和与系统观测性的直接关系,给出了在保证系统可观测性的同时,使得测试代价最小的测试矩阵优化方法.算例表明,提出的方法简单直观,对配置测试向量具有良好的工程价值.     

关于独立学院教学体制的构建

独立学院作为一种新型的办学模式，是高教改革的战略抉择，对我国高等教育向“大众化教育”转变具有重要的意义。构建合理的独立学院教学体制是实现人才培养的关键。对此，独立学院必须以培养应用型专门人才为目标，以市场为导向，科学确定学生的知识结构和能力体系，构建合理的人才培养模式；应根据独立学院的特点，以教学运行管理为重点，加强教学管理的规范化建设，构建合理的教学管理机制；以提高教学质量为目标，构建合理的教学质量监控与保障体系；充分运用独立学院灵活的办学机制，构建一支由母体高校教师、专任教师和兼职教师三部分组成的，适应独立学院教学工作需要的教师队伍。     

电磁场的对称性与左性电磁波

根据对称性原理，在假设磁单极存在条件下，对Maxwell方程的不对称性进行了改进推导，提出与右性电磁波相对称的左性电磁波，讨论左性电磁波出现的必然性、产生方法及其主要特性。     

和谐思维与部队思想政治教育职能优化

军队思想政治教育要适应和谐社会的要求,一方面深化调节,注重满足军人自身发展的需要,引导官兵建立与和谐社会相融合的人际关系;另一方面,运用“和”的思想解决矛盾和问题,达到对官兵负面思想的有效控制。     

车辆悬挂系统的主动优化控制器设计及仿真

基于特征结构配置参数化结果,提出了车辆悬挂系统的主动优化控制器设计方法。该方法直接基于车辆悬挂系统的参数矩阵,便于工程应用。车辆悬挂系统的仿真实例表明所提主动优化控制器设计方法简单且有效。     

谈峨眉山景区消防规划编制

针对世界自然和文化双遗产的峨眉山景区的消防安全现实情况，分析了该景区主要面临的消防安全问题，提出了在编制自然和文化遗产地自然消防规划时应注意的问题及解决办法。     

关于奥运临时用房消防设计问题的技术探讨

由于奥运临时用房项目建设的临时性、特殊性、紧迫性，导致了部分项目的消防设计存在难以满足现行规范的问题。笔者作为消防设计审核人员，以“为建筑内人员提供安全保障；为消防人员提供消防条件，保障其生命安全；尽量减少财产损失；保护结构安全；尽量减少对正常营运的干扰。”为安全目标，利用消防性能化设计，完善了消防设计中的火灾防控技术措施。     

The building evacuation problem with shared information

In this article, the Building Evacuation Problem with Shared Information (BEPSI) is formulated as a mixed integer linear program, where the objective is to determine the set of routes along which to send evacuees (supply) from multiple locations throughout a building (sources) to the exits (sinks) such that the total time until all evacuees reach the exits is minimized. The formulation explicitly incorporates the constraints of shared information in providing online instructions to evacuees, ensuring that evacuees departing from an intermediate or source location at a mutual point in time receive common instructions. Arc travel time and capacity, as well as supply at the nodes, are permitted to vary with time and capacity is assumed to be recaptured over time. The BEPSI is shown to be NP‐hard. An exact technique based on Benders decomposition is proposed for its solution. Computational results from numerical experiments on a real‐world network representing a four‐story building are given. Results of experiments employing Benders cuts generated in solving a given problem instance as initial cuts in addressing an updated problem instance are also provided. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

一种改进的事件驱动系统框架

在给出事件驱动系统安全漏洞的基础上,指出了产生漏洞的根本原因是:系统忽视了输入系统的事件序列之间存在的相关性;系统无条件信任任何事件源产生的事件.针对这两个原因,相应提出了事件序列形式安全分析模型及基于事件源的可信度评估模型,依据这两个模型,构建了一种改进的事件驱动系统框架.