A quadratic time exact algorithm for continuous connected 2-facility location problem in trees

This paper studies the continuous connected 2-facility location problem (CC2FLP) in trees. Let \(T = (V, E, c, d, \ell , \mu )\) be an undirected rooted tree, where each node \(v \in V\) has a weight \(d(v) \ge 0\) denoting the demand amount of v as well as a weight \(\ell (v) \ge 0\) denoting the cost of opening a facility at v, and each edge \(e \in E\) has a weight \(c(e) \ge 0\) denoting the cost on e and is associated with a function \(\mu (e,t) \ge 0\) denoting the cost of opening a facility at a point x(e, t) on e where t is a continuous variable on e. Given a subset \(\mathcal {D} \subseteq V\) of clients, and a subset \(\mathcal {F} \subseteq \mathcal {P}(T)\) of continuum points admitting facilities where \(\mathcal {P}(T)\) is the set of all the points on edges of T, when two facilities are installed at a pair of continuum points \(x_1\) and \(x_2\) in \(\mathcal {F}\), the total cost involved in CC2FLP includes three parts: the cost of opening two facilities at \(x_1\) and \(x_2\), K times the cost of connecting \(x_1\) and \(x_2\), and the cost of all the clients in \(\mathcal {D}\) connecting to some facility. The objective is to open two facilities at a pair of continuum points in \(\mathcal {F}\) to minimize the total cost, for a given input parameter \(K \ge 1\). This paper focuses on the case of \(\mathcal {D} = V\) and \(\mathcal {F} = \mathcal {P}(T)\). We first study the discrete version of CC2FLP, named the discrete connected 2-facility location problem (DC2FLP), where two facilities are restricted to the nodes of T, and devise a quadratic time edge-splitting algorithm for DC2FLP. Furthermore, we prove that CC2FLP is almost equivalent to DC2FLP in trees, and develop a quadratic time exact algorithm based on the edge-splitting algorithm. Finally, we adapt our algorithms to the general case of \(\mathcal {D} \subseteq V\) and \(\mathcal {F} \subseteq \mathcal {P}(T)\).     

Availability analysis for general repairable systems with repair time threshold

Availability analysis is an important issue in many practical fields. This paper investigates the availability for general repairable systems with repair time threshold. Based on practical applications, a repair time threshold is introduced. If the period of a repair is less than a predefined time threshold, then the system may be considered as working during this period, i.e., the effect of the repair could be neglected. Otherwise, if the period of a repair is longer than the given threshold, then the system is considered as working from the beginning of the system failure until the repair time exceeding the threshold, i.e., the time point of the system down could be delayed. We consider both constant and random repair time threshold. This paper valuates the user-perceived availability, when the user does not experience any service interruption because the duration of repair is too short. The results can be applied in reliability engineering, queueing theory and many other fields. A numerical example for ventilator system is presented to demonstrate the application of the developed approach.     

论黑龙江省地名与古代民族的关系

本文论述了黑龙江省地名学与古代民族的历史关系。     

属性关系与诊断测验分类影响的探讨

认知诊断模型-DINA模型假定属性之间是相互独立、非补偿的关系,但在实际应用中,属性之间有可能存在补偿关系.文章探讨了在不同的被试总体下,DINA模型在属性之间独立和存在补偿关系时作答数据上的表现,结果表明,当测验中有部分属性间存在补偿关系时,会给DINA模型诊断分布带来较大的影响,在固定其他条件(被试人数、随机因子)条件下,存在和不存在补偿作用所导致的诊断分类率之间有显著差异,且在不同大小补偿作用下,诊断分类率之间的差异显著;随着随机因子的增加,不同大小的补偿因子所导致的诊断分类率之间的差异会变小,补偿因子和随机因子之间存在着显著的交互作用.     

青少年公民教育的发展脉络、现实问题与未来方向

青少年公民教育是新时期促进国家发展,增加国家实力的基本保障。由于相关概念内涵的模糊不清、推行机制的不完善等原因,导致了我国青少年公民教育的理论体系和实施体系建设的相对滞后。直至20世纪90年代以后在国际和国内环境的双重推动下。青少年公民教育才开始有了实质性的发展和推进:同时也存在着理论体系建构滞缓、教学理念混淆、课程衔接乏力、教育内容知行脱节等现实问题。构建一个适应时代发展需求,符合青少年身心发展特征。校内外有机结合的积极有效的青少年公民教育体系成为了新时期发展青少年公民教育的重要任务。     

课堂场域中的矛盾冲突及其因应方略

教师主体与学生主体在课堂教学场域的时空里通过交往和对话形成了由低级到高级的"自在性共同体"、"群集性共同体"和"自为性共同体"三种具体形态的共同体。不管以哪一种形态的共同体为中心来设定课堂教育教学活动,其教育教学实践中的人际关系、文化知识学习等方面都具有显著的自身特点,存在不同的教育教学实践的矛盾冲突。解决课堂教育教学实践中矛盾冲突引发的困境应当从掌握教育教学内容、维护课堂秩序、适应习惯、评价与认可四个范畴入手,制定因应的方略,经营课堂教育教学活动,才能更好地传承文化意识、优化师生关系、彰显教育教学情境中和谐的动态的生命力。     

An improved two-stage procedure to compare hazard curves

Qiu and Sheng has proposed a powerful and robust two-stage procedure to compare two hazard rate functions. In this paper we improve their method by using the Fisher test to combine the asymptotically independent p-values obtained from the two stages of their procedure. In addition, we extend the procedure to situations with multiple hazard rate functions. Our comprehensive simulation study shows that the proposed method has a good performance in terms of controlling the type I error rate and of detecting power. Three real data applications are considered for illustrating the use of the new method.     

布朗功能学派理论对林耀华东南宗族研究的影响

通过比较林耀华早期的经验研究和1936年拉德克里夫-布朗（A .R .Radcliffe-Brown）在燕京大学的讲学课程，发现了二者在社区研究等理论方面的相通之处。林耀华通过在东南宗族乡村作出的实地调查，发现宗族的社会学特点：宗族的经济功能基于血亲间的分工合作，其情感结构面向祖先和国家，是开放而又复合的。在面对市场时，宗族作为整体积极参与其中。在面对国家时，宗族接纳了国家的权力系统。宗族即是布朗所讲的“活”的功能体，具备适应现代化的能力。因此，林耀华一直坚持用宗族作为中国社会现代化问题的研究单位。