基于台风场景模拟的配电网架空线路薄弱环节辨识方法

为降低台风造成的配电网负荷和经济损失,需对配电网架空线路的薄弱环节进行辨识。首先,考虑台风预报信息及其不确定性,利用Batts模型刻画台风登陆后风场各点风速及其衰减过程;然后,基于电杆风荷载与抗弯强度的关系建立电杆与线路故障率模型;同时,综合考虑线路故障频率及供电负荷重要程度定义线路脆弱度指标,并采用层次分析法确定指标中各因素权重;最后,提出一种台风场景下基于蒙特卡罗法的配电网架空线路薄弱环节辨识方法。典型算例结果表明,以所提方法确定的线路薄弱环节作为加固配电网混凝土电杆、分配应急发电车的依据,可有效降低台风灾害下配电网负荷和经济损失。     

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.     

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.     

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。     

可持续发展视角下 PPP 项目脆弱性研究

在 PPP 项目非理性过热发展中,各种问题如私人资本的短视行为、隐形债务风险增加等弊端屡见不鲜。为了衡量一个 PPP 项目暴露在恶劣环境下发生不利影响的程度、恢复正常功能的能力,促进 PPP 项目的可持续性发展,从大量文献与案例出发,识别 PPP 项目的关键影响因素,从外部环境、项目特征、参与主体与合作机制 4 个方面构建 PPP 项目脆弱性影响因素指标体系。引入系统动力学,深入分析各影响因素的因果关系,运用 Vensim 软件仿真分析各影响因素对整体脆弱性的影响,为 PPP 项目的可持续发展提供决策依据。     

Exogenous pressures and probabilistic assessment of risk and vulnerability of urban water systems in Ghana

ABSTRACT

Risk and vulnerability assessment of urban water systems can be extended to include several components. This work formulates a probable quantitative assessment of risk and vulnerability of urban water system based on climatic conditions and urban population growth. Climate change scenarios and population projections are used to estimate susceptibility to water supply systems’ risk and vulnerability. Quantile regression was used to establish the exponent correlation between the climate variables and population; and evaluate their consequential influences on urban water supply systems. We complemented the analysis with a probabilistic model to assess the robustness of urban water system that depends wholly on the climate for freshwater source. The study established that Climatic conditions, though uncertain, point to freshwater deficiency in the future. Moreover, population trends project a higher urban population thereby increasingly lowering water per capita and subsequently leading to doubtful urban water system’s resilience to the exogenous pressures.     

Regional loss estimation due to hurricane wind and hurricane-induced surge considering climate variability

This paper presents a framework to assess the potential hurricane damage risks to residential construction. Studies show that hurricane wind, frequency and/or hurricane-induced surge may change as a result of climate change; therefore, hurricane risk assessments should be capable of accounting for the impacts climate change. The framework includes a hurricane wind field model, hurricane-induced surge height model and hurricane vulnerability models. Three case study locations (Miami-Dade County, FL; New Hanover County, NC and Galveston County, TX) are presented for two types of analyses: annual regional loss estimation and event-based regional loss estimation. Demographic information, such as median house value and changes in house numbers, and distribution of houses for different exposures, is used to estimate the time-dependent probability of damage with or without possible climate change-induced change in wind speed, frequency and/or surge height. Through both analyses, it was found that climate change may have a significant impact on regional hurricane damage losses.