一种考虑节点功率的电网连锁跳闸评估方法

针对电力系统的连锁跳闸问题,结合继电保护的动作行为,研究了一种基于模式识别技术的连锁跳闸评估方法。首先根据电网连锁跳闸的通常表现行为,并结合电流型和距离型后备保护的动作行为,通过分析,论证了电网节点注入功率对于连锁跳闸的决定作用。在此基础上,提出了利用模式识别技术对电网是否发生连锁跳闸进行评估的方法,该评估方法主要针对电网在给定的节点注入功率状态下电网是否会因给定的初始故障发生连锁跳闸,并给出了采用模式识别技术时的样本结构,相应的模式识别技术以及操作流程。IEEE39系统的算例验证了这种评估方法的有效性。     

欺骗邮件横行校园网

本刊讯 近日,有多所学校的邮件服务器被欺骗邮件所困扰。这类采取“社会工程学（social Engineering）”欺骗方式的恶意邮件,骗取内部人员的信任并绕过所有技术上的保护,旨在取得用户的用户名以及密码,从而实施进一步的欺骗行为。     

基于James技术的企业电子邮件附件过滤系统

随着互联网技术的飞速发展,电子邮件已经成为必备的网络服务之一.以Apache开源项目James框架作为邮件收发平台,MySQL完成后台数据库设计,使用基于JavaEE技术的SaStruts框架实现的企业电子邮件附件过滤系统,能够智能区分企业内部邮件和外部邮件,解决邮件服务器上滞留大量附件的问题.     

基于邮件社区的垃圾邮件发现方法

充分考虑了邮件通信网络中社区的性质,并在此基础上提出了一种垃圾邮件发现方法.首先,该方法根据邮件通信行为特征区别垃圾邮件与非垃圾邮件,避免了对邮件正文的操作,在某种程度上保护了用户隐私;其次,该方法可作为现有垃圾邮件处理引擎的补充,组合现有方法提高垃圾邮件处理准确度;最后,为垃圾邮件处理的研究提供了一种新的思路,对于保护邮件机密信息、净化邮件通信环境有十分重要的意义.     

新闻视频图像中的模式识别技术研究

本文概述了新闻视频图像研究中所涉及到的多种模式识别技术,分别对各模式识别技术的发展历史和研究状况作了介绍与评论,剖析了它们的优点和不足.讨论了新闻视频图像中模式识别技术的最新发展方向及其国内的发展情况.     

校园网反垃圾邮件网关部署方案研究

首先介绍了垃圾邮件的概念及发送技术,然后详细阐述了各种反垃圾邮件技术的特点.分析了校园网反垃圾邮件的特点,给出了不同的反垃圾邮件网关部署方案并分析了不同方案的特点与缺陷.     

垃圾邮件过滤系统模型的研究与设计

邮件过滤是反垃圾邮件的一种重要方法,其中基于邮件内容的过滤又是一种重要的、有效的过滤手段.基于电子邮件是一种半结构化的数据,并且,电子邮件中主要包括的是文本信息,因此,本文将文本挖掘的分类技术和方法引入到邮件过滤系统模型中,以实现对垃圾邮件的过滤.     

嵌入式应用系统邮件发送模块的C语言编程

文章阐述用C语言设计实现嵌入式应用系统邮件发送模块的技术要点及关键步骤,包括嵌入式系统对邮件发送功能需求的简要分析、实现邮件发送功能的基本原理、C语言设计实现的具体方法等.最后通过一个小型CGI程序演示其功能,实现基于Web的邮件发送.通过在X86平台和ARM平台分别实验,都达到预期效果.该邮件发送模块在Linux平台用GNU工具链作开发,整个程序小巧简洁、功能独立,可在任何嵌入式应用系统中使用,很有实用价值.     

基于多路复用的群集邮件系统的研究与实践

在分析目前高校邮件系统面临问题及传统解决方案存在不足的基础上,讨论了实现横向可伸缩性,可用于连接到多个邮件服务器的单一域名,以使整个邮件服务器阵列作为一个单一主机呈现给邮件用户的多路复用器技术,并给出了中国农业大学基于此技术的群集邮件系统的应用实践.     

邮件过滤系统的设计与实现

本文介绍了邮件过滤技术,提出了一种邮件过滤系统的设计思想,该系统整合了多种邮件过滤技术,提高了邮件过滤系统的效率。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

Western and Eastern culture differences in commercial field

The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity.     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

风的曲线

Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose.     

团图为数的图中的闭团贯数

Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.