Nonperiodic preventive maintenance for repairable systems

As a complex system with multiple components usually deteriorates with age, preventive maintenance (PM) is often performed to keep the system functioning in a good state to prolong its effective age. In this study, a nonhomogeneous Poisson process with a power law failure intensity is used to describe the deterioration of a repairable system, and the optimal nonperiodic PM schedule can be determined to minimize the expected total cost per unit time. However, since the determination of such optimal PM policies may involve numerous uncertainties, which typically make the analyses difficult to perform because of the scarcity of data, a Bayesian decision model, which utilizes all available information effectively, is also proposed for determining the optimal PM strategies. A numerical example with a real failure data set is used to illustrate the effectiveness of the proposed approach. The results show that the optimal schedules derived by Bayesian approach are relatively more conservative than that for non‐Bayesian approach because of the uncertainty of the intensity function, and if the intensity function are updated using the collected data set, which indicates more severe deterioration than the prior belief, replacing the entire system instead of frequent PM activities before serious deterioration is suggested. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

Analytic solution for the nucleolus of a three‐player cooperative game

The nucleolus solution for cooperative games in characteristic function form is usually computed numerically by solving a sequence of linear programing (LP) problems, or by solving a single, but very large‐scale, LP problem. This article proposes an algebraic method to compute the nucleolus solution analytically (i.e., in closed‐form) for a three‐player cooperative game in characteristic function form. We first consider cooperative games with empty core and derive a formula to compute the nucleolus solution. Next, we examine cooperative games with nonempty core and calculate the nucleolus solution analytically for five possible cases arising from the relationship among the value functions of different coalitions. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

Supply chain coordination with shelf‐space and retail price dependent demand and heterogeneous retailers

We consider supply chain coordination in which a manufacturer supplies some product to multiple heterogeneous retailers and wishes to coordinate the supply chain via wholesale price and holding cost subsidy. The retail price is either exogenous or endogenous. The market demand is described by the market share attraction model based on all retailers'shelf‐spaces and retail prices. We obtain optimal solutions for the centralized supply chain, where the optimal retail pricing is a modified version of the well‐known cost plus pricing strategy. We further get feasible contracts for the manufacturer to coordinate the hybrid and decentralized supply chains. The manufacturer can allocate the total profit free to himself and the retail market via the wholesale price when the retail price is exogenous, but otherwise he cannot. Finally, we point out that different characteristics of the retail market are due to different powers of the manufacturer, and the more power the manufacturer has, the simpler the contract to coordinate the chain will be. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

基于fMRI的静息状态脑功能复杂网络分析

分析静息状态下人脑中不同区域之间的功能连接模式对研究静息状态下人脑正常功能活动具有重要意义。基于复杂网络理论对脑功能网络进行建模,考察静息状态脑功能网络的结构和拓扑特性。结果显示,网络具有小世界性质和无标度特性。进一步引入一种概率混合模型分析网络社团结构,得到的10个子网络中包含视觉系统、听觉系统、运动系统、默认网络以及与执行和工作记忆相关的脑区。推测出静息状态脑功能网络是由这些相对独立又彼此关联的子网络组成,其中楔前叶和扣带回作为网络的关键节点,在信息调度和传递中占据重要地位。     

基于条件熵的不完备信息系统属性约简算法

在相容关系下定义了三种不完备条件熵——H′条件熵、E′条件熵和I′条件熵,并对它们的性质进行了分析比较,研究发现,H′条件熵和I′条件熵不适用于相容关系下信息观点的约简。利用E′条件熵刻画信息系统中属性的相对重要性,设计了一种新的基于信息论观点的启发式约简算法,它统一了完备信息系统与非完备信息系统中的约简方法。通过实例说明,该算法能得到决策表的相对约简。     

从评价系统看小说人物刻画——以《傲慢与偏见》的两封信为例

本文以系统功能和评价系统理论为依据,分析《傲慢与偏见》中两封信的表现态度系统的语义资源。经过分析笔者发现两封信截然不同的语言表达方式是小说中不同人物性格的外在表现。小说是很好的语言学习材料,我们在分析小说的同时,也让我们欣赏到了作者刻画小说人物的精湛处理。     

地理信息系统专业实践教学体系研究

实践教学是GIS专业教学至关重要的环节。结合GIS知识体系结构、专业特点和社会需求,讨论了GIS专业实践教学体系的基本框架及其依托。     

建设社会主义核心价值体系大力弘扬时代精神

社会主义核心价值体系是社会主义意识形态的本质体现。马克思主义指导思想是社会主义核心价值体系的旗帜与灵魂。社会主义核心价值体系是中国共产党领导人民建设中国特色社会主义的共同价值追求;以爱国主义为核心的民族精神和以改革创新为核心的时代精神是社会主义核心价值体系的精髓;弘扬以改革创新为核心的时代精神是建设社会主义核心价值体系的根本途径;大力弘扬以改革创新为核心的时代精神是实现中华民族伟大复兴的强大动力。     

线性相依风险下的超额赔款再保险

本文从保险人的角度研究对两类相依风险的超额赔款再保险的最优自留额问题。考虑指数效用函数的货币期望效用原则和自留累积损失的调节系数原则,得到关于这两个问题的最优解的方程。     

基于层间嵌入式多级支持向量机的特征选择

针对多故障样本一次性映射之后分类不理想,研究了多级层次式支持向量机,应用UCI数据仿真,结果表明该方法缩短了训练时间、提升了测试准确率、改善了样本的可分类性。由于误差积累,在此基础上,提出了层间嵌入式多级支持向量机,采用Abalone数据仿真,结果表明分类精度有所提高并减少了分类步骤。结合ReliefF算法,对制导设备的故障特征参数进行了选择。