基于分布式多层无线传感器信息融合中的关联算法探索

基于多层无线传感器具有可快速部署、可自组织、隐蔽性强和容错性高的特点,利用多层无线传感器网络能够实现对敌军兵力和装备的监控,战场实时监视,目标定位,战场评估等功能,实现分布式多层无线传感器信息融合中的关联算法研究.     

六边形网格划分的混合传感器网络调度方法

在混合无线传感器网络中,如何对动态节点进行合理调度以降低能耗并延长网络寿命一直是无线传感器网络研究的一个重要课题。本文针对大型的混合无线传感器网络,提出了一个基于正六边形网格划分的动态节点分布式调度方法,即通过网格划分的方式将此调度问题转化为一个多目标规划问题,并改良了方向网格划分下的节点通信机制,在保证各个动态节点能耗尽量均衡的情况下,降低动态节点能耗,减少传感器网络中总的数据包发送量,提高网络的综合性能。与其他的分布式算法和集中式算法的仿真对比表明了本文算法的有效性。     

无线传感器网络的分簇算法建模与OPNET仿真实现

传感器技术、微机电系统、现代网络和无线通信等技术的进步,推动了具有现代意义的无线传感器网络的产生和发展。无线传感器网络能够广泛地应用于恶劣环境和军事领域中。本文通过对无线传感器网络特点的分析,提出了基于信道接入的多跳算法网络结构,给出了OPNET仿真模型,分析了相关仿真结果。     

无线传感器网络安全技术专利申请状况分析

正无线传感器应用在军事、安全监控、环境监控、抗震救灾等多个领域,因而网络安全问题更是无线传感器付诸应用的根本前提,本文从专利申请时间、申请人国别、IPC分类号等方面阐述了无线传感器网络安全技术的发展历程,并从密钥管理、入侵检测、网络协议、安全数据融合几个角度对现有技术的优缺点进行对比,提出了无线传感器网络的安全解决方案。     

基于Mean Shift算法的人脸跟踪

人脸跟踪是视频检索、视觉监控等领域中的一项关键技术,随着机器视觉技术的发展,实现人脸跟踪的算法也是多种多样。将人脸跟踪问题近似于一个meanshift跟踪问题,选取面部的颜色特征作为跟踪模板,并在MATLAB中进行了仿真,得到了良好的实验效果。     

无线传感器网络研究现状与应用

无线传感器是物联网中的主要构成部分,能收集各项活动运行中产生的信息,在社会多个领域有很好应用。本文主要围绕无线传感器网络研究现状、无线传感器网络的应用分析等方面展开讨论,具体分析了无线传感器网络研究现状和关键技术,最后论述了无线传感器在不同领域的应用,以便为之后的理论研究提供参考。     

基于粒子滤波的无线传感器网络目标跟踪

本文首先介绍了PF(Particle Filter)和UPF(Unscented Particle Filter)的基本原理,然后针对无线传感器网络(WSN)目标跟踪这一应用方向,采用等级网络结构,参考分布式粒子滤波算法,将UPF应用于WSN单目标跟踪以提高网络跟踪精度,仿真证明UPF较PF在跟踪精度上确实有明显的提高。     

基于WSN及GIS的区域实时监控构想

在监控区域内广泛布撒无线传感器节点,利用无线传感器网络WSN（Wireless Sensor Network）综合定位获取目标位置信息,并在地理信息系统GIS（Geographic Information System）中显示,实现目标实时可视化的监控。     

基于混合高斯模型与差分法的运动目标检测

视频监控涉及计算机视觉、模式识别和人工智能等多个领域,它是指在不同环境下对人和车辆进行的实时观察,根据观察对象的动作、行为进行分析,为用户提供信息。视频监控过程分为运动目标检测、目标跟踪、目标分类和目标分析。     

基于能耗节约的异构无线传感器网络目标点覆盖算法

提出了一种适用于异构无线传感器网络的目标点节能覆盖算法.本文将传感器的任务调度周期分为初始阶段和工作阶段,在初始阶段计算出无线传感器的感测能力并作出感测元件开启与否的决策,并在工作阶段实现对目标点的覆盖.对于一个给定的无线传感器,根据它的剩余电量及其一跳邻居的电量和所搭载的感测元件类型,对该传感器所搭载的感测元件的开启与否作出决定,并将决策信息广播到它的一跳邻居.仿真实验结果表明,本文算法的性能略低于最优的ILP算法,可以有效降低无线传感器网络目标点覆盖过程中的能量消耗,并有效地延长了无线传感器网络的生存时间.     

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.     

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.     

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.     

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