基于网络传播特性的配电网电压暂降随机预估方法

敏感负荷的大量投运使得用户对电能质量的要求不断提高,电压暂降的快速有效预估成为当前电压暂降研究的一项重要内容。提出了一种基于网络传播特性的配电网电压暂降随机预估方法。首先基于配电网拓扑搜索电压暂降传播路径,通过序分量法获得不同路径下电压暂降的垂直/水平传播特性。进而根据路径搜索结果建立故障源至负荷侧的配电网电压暂降传播方程。最后结合不同故障类型及线路故障率计算暂降凹陷域和相应预估指标。对某实例配电网系统开展算例分析,验证了所提方法的有效性与优越性。     

Application of ontology in vulnerability analysis of metro operation systems

Vulnerability analysis plays a key role in the metro operation system, since the metro operation security has become more important than ever. The vulnerability management is a systems engineering, it covers different departments of the metro operation company. A successful vulnerability management needs the close cooperation and coordination between them. However, it has blocked a successful vulnerability management due to lack of the common knowledge basis. This paper applies ontology into the vulnerability analysis of the metro operation system and illustrated the major design ideas of the ontology model. Examples are given as well to demonstrate the implementation of knowledge reasoning based on the ontology. The ontology was also evaluated through expert evaluation for further improvement. By using this technology, a common knowledge base of the vulnerability management in the metro operation system can be built. It provides information sharing, communication and collaboration for all the participants in the system for decision-making. Moreover, further development of the intelligent application can be built based on it, efficiently increasing the management level of the vulnerability.     

A combined methodology for the hydraulic rehabilitation of urban drainage networks

During medium and high intensity storm events, urban drainage networks can rapidly reach their maximum capacity, and subsequently floods can occur. Owing to the non-linearity of the processes involved, it is evident that the return period of a rainfall is different from the return period of the generated overflows. Therefore, the assessment of the maximum overflow volume related to a given return period is a key element in the management of urban drainage networks, since it may cause problems to infrastructure and economic losses. In this paper, a combined methodology for the hydraulic rehabilitation of such networks is proposed, by expressing their hydraulic critical conditions in terms of overflow volumes rather than rainfall volumes and considering both observed rainfall data and synthetic hyetographs derived from statistical analysis. The first application of the proposed methodology to the sewer network of the Mesola Municipality is presented and commented on.     

基于业务的电力通信网络脆弱性分析评价方法

为解决传统复杂网络理论脆弱性分析的局限性并改善网络性能,提出了一种基于业务的电力通信网络脆弱性分析方法。利用复杂网络理论构建网络模型,将业务重要度和业务流量作为网络参数,在蓄意攻击和随机攻击的策略下,以链路或节点失效所造成的业务量损失大小来描述网络的脆弱性,并找出网络中相应的脆弱部位。以电力IEEE30节点测试系统作为仿真实例,结果表明,网络业务分布越不均匀,网络脆弱性就会越高,进而网络抵御级联故障的能力就越差。而且在蓄意攻击的情况下,网络脆弱性极高。得出结论,网络业务分布越均匀,网络脆弱性就会越低。针对结论,提出了改进业务路由策略的方法以降低网络的脆弱性。仿真证明了该方法的有效性和可用性,并可为电力通信网络规划和维护提供参考,具有现实意义。     

穿甲弹对均质装甲板毁伤效能的数学研究

为了讨论用数学方法研究穿甲体毁伤效能、靶板结构易损性和毁伤程度之间关系的可行性。以特定的弹目系统为例,结合穿甲体毁伤效能、靶板结构易损性和毁伤程度的数学定义,对不同着速时穿甲体毁伤效能、靶板结构易损性和毁伤程度进行了计算和数值拟合。结果表明穿甲体毁伤效能、靶板结构易损性和毁伤程度之间有明显的函数关系,可以用数学的方法进行研究。     

Disaster Recovery Among Multiethnic Immigrants: A Case Study of Southeast Asians in Bayou La Batre (AL) After Hurricane Katrina

Problem, research strategy, and findings: Immigrants suffer disproportionately from disasters because they have limited capacity to prepare for, respond to, or recover from a disaster. Unfortunately, planners and emergency managers are often inadequately trained or educated about the unique sociocultural needs and assets among immigrant groups. Hurricane Katrina exposed challenges to long-term recovery among Southeast Asian immigrants in Bayou La Batre (AL). We employ qualitative research methods, including in-depth interviews, focus groups with immigrants, and site visits, to better understand the barriers to disaster recovery and to inform local, state, federal, and nongovernmental agencies on how to better prepare disaster plans that would improve disaster recovery for multiethnic, multicultural, immigrant populations. We find four significant categories of sociocultural barriers to disaster recovery for Southeast Asian immigrants in Bayou La Batre: 1) language, literacy, and communication; 2) cultural differences in help-seeking; 3) inability to navigate the disaster recovery bureaucracy; and 4) and lack of leadership. Despite these barriers to recovery, immigrant groups can also teach us about resiliency in the face of disaster. The levels of trust, cooperation, and collaboration within the ethnic immigrant community help to buffer the damaging effects during the response and recovery period.

Takeaway for practice: Our study reveals that cultural competency among staff members engaged in preparedness, response, and recovery is essential for an effective disaster recovery process. Furthermore, engaging immigrant groups in long-term recovery requires trust and relationship building prior to a disaster. In doing so, more culturally appropriate and effective disaster recovery plans can be developed.     

A decision-making framework for justifying a portfolio of IT projects

This paper presents a comprehensive decision-making framework for evaluating a portfolio of IT projects. A problem of IT project selection with and without project interdependencies is considered. The problem is subject to maximum project funding budget constraint. When IT project portfolio contains independent projects, a dynamic programming (DP) solution procedure is proposed to efficiently solve the portfolio of IT projects' problem. However, when IT project portfolio contains project interdependencies, a mixed integer programming (MIP) approach is needed to solve the problem optimally. Experiments and results using simulated data using Monte Carlo simulation are provided. The results indicate that a large set of project selection problems containing up to 60 projects can be solved easily using the proposed decision-making framework.     

节点变形对在役混凝土框架地震易损性影响分析

在设计中按照"强节点、弱构件"的原则进行结构设计,地震作用下,节点区域的变形很小,因此在结构分析中节点通常假定为刚性。随着结构龄期变化,结构将产生耐久性损伤,节点区域变形增大,此时要通过节点区域的直接建模来考虑其变形对结构抗震性能的影响。以典型6层混凝土框架为例,用两种不同节点建模方法建立整体结构模型,对不同龄期的结构进行易损性分析,建立了结构的时变易损性模型。研究表明,考虑节点区域变形的结构失效概率偏大,其偏差幅度和速率随着龄期和峰值加速度的增大而增大。     

基于节点集合的PMU优化配置方法

同步相量测量单元(PMU)的最优配置要求在全局可观的前提下所配置的PMU最少。0-1线性整数规划在分析求解多目标PMU最优配置有极大的优势。在实际电力系统中存在一定数量的零注入节点。作为虚拟测量数据,虽然有利于PMU最优配置,然而引入到整数规划进行计算时,将使模型非线性化而难以求解。给出了考虑零注入功率节点情况下的条件函数,该函数能够有效保持函数的线性性从而仍能适用于0-1整数规划。当考虑N-1情况下的PMU最优布点时,该方法具有很强的继承能力,有效解决了传统方法无法解决的N-1优化配置问题。最后将该方法应用于IEEE14节点以及IEEE39节点的算例,相对于其他配置方法,减少了PMU配置数量,从而体现了该方法的优越性。     

基于0-1整数规划算法的PMU量测点优化配置新方法

为了提高同步相量测量装置的优化配置速度,提出了基于0-1整数规划算法的PMU量测点优化配置方法。在0-1整数规划算法的基础上,根据节点的可观测性建立数学模型,考虑节点间的相互关系构建邻接矩阵并进行分析,求解量测点模型获得量测配置优化位置。对IEEE-14和IEEE-18节点系统进行实验仿真,并利用Lingo工具验证所提0-1整数规划算法,获取PMU优化位置和速度。该算法与未改进的0-1整数规划算法相对比,结果表明,该方法减少了变量数目,简化了约束条件,减少了迭代次数,提高了收敛速度,验证了所提方法的有效性和实用性。