GOOSE报文在数字化变电站中的应用

通过对数字化变电站相关知识的学习,结合本局数字化变电站的建设情况,对面向通用对象的变电站事件(GOOSE)报文模型进行分析,对 GOOSE 报文通信传输的方式,GOOSE 通讯要求及其实时性的要求进行介绍,认识到在数字化化变电站中采用 GOOSE 报文传输信息的必要性和重要性.     

基于UDP协议的气象数据通信软件的设计与实现

介绍了基于UDP的高效的气象数据通信的设计与实现.为提高UDP报文的传输效率,提出了一种应用层选择重传协议;针对数据源种类繁多、来源多样的特点,设计并实现了高效的被动式目录监控方法;为有效利用带宽,采用了增量式方式提高了实时报文的传输效率.     

一种基于优先级发送的GOOSE网络数据实时传输方法

研究IEC61850标准下GOOSE报文的采集、转换和传输的相关问题,提出一种新的报文发送方式.GOOSE网络报文依据优先级高低依次发送,在硬件方面采用一种基于FPGA+ARM的系统架构,成功解决发送端GOOSE报文发送具有延迟和传输不确定的问题,测试结果表明,系统性能稳定,实现GOOSE网络数据的实时传输.     

网络通信的安全加密技术初探

随着计算机技术应用的日益广泛,计算机通信链路的脆弱性成为计算机网络系统的重要安全威胁.简要探讨了采用链路加密设备的方式来加强传输信息的私密性,在数据报文后增加MAC处理以确保通信信息的完整性.     

基于XML的EDI报文处理模型

本文介绍了目前常用的EDI标准格式报文处理情况,总结基于XML格式的EDI报文在商业传输上的优势,提出JDOM+Hibernate模型作为解析XML报文并将其导入关系型数据库的解决方案。     

集控站网络化数据采集及规约的探讨

介绍了集控站通信结构和通信规约,分析讨论集控站网络化数据的传输特点及优先级,论述了集控站网络化数据采集传输结构,并对远动信息网络传输进行了详细描述。最后,具体分析了规约在实际应用中出现的数据传输优先级。     

点对点报文传输系统的开发

对采用MODEM传输报文系统的开发方法进行具体介绍。     

激光雷达深度信息安全传输端口设计

用于激光雷达数据信息传输的端口是雷达系统的关键组成部分,详细阐述了基于3.0总线的激光雷达深度信息安全传输端口的软硬件设计。接口的硬件部分由电路、3.0芯片、单片机等单元构成,介绍了传输端口单片机主程序及应用程序,提出以傅里叶变换为基础的动态向量端口算法,可以满足激光雷达信号数据传输实时性的要求。仿真实验证明,提出端口设计硬件开销低,同时具有良好的稳定性和安全性,可以有效提升数据传输量。     

智能变电站过程层组网方式与报文传播策略分析

为保证智能变电站过程层网络传输的实时可靠性,合理的组网方式和报文传播策略尤为关键。本文通过分析智能变电站过程层网络特点及基本组网方式差别,剖析了SV/GOOSE星形分网的组网方案在网络传输性能方面的优势。并在此组网方式的基础上,研究分析VLAN、动态组播和静态组播三种报文传播策略,提出星形分网和静态组播相结合的组网策略,满足现阶段智能变电站过程层报文传输实时性和可靠性的应用需求,并以琴韵变电站现场应用案例验证了该结论的合理有效性。     

一种改进的AODV安全路由协议

针对Ad Hoc网络的黑洞攻击问题,基于AODV协议提出一种采用“逆向逐节点验证”的解决方案.本方案使用控制报文和数据报文检查网络中是否存在黑洞节点,确定黑洞节点的位置并进行排除.中间节点也对可疑节点进行验证,将黑洞攻击危害降到最低.与现有其他方案的比较表明,改进的方案在有效抵御针对Ad Hoc网络黑洞攻击的同时,具有更低的网络开销和网络延迟.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

Low doses of a red wine ingredient figh diabetes in mice

Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Molecular motor assembly of a biomimetic system

Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence