基于路由热点循迹修正的WSN发射功率优化调度

无线传感器网络WSN发射功率的优化调度是决定WSN使用寿命和提高WSN性能的关键,WSN路由节点的在进行数据转发时会导致热点随机扩散,发射功率无法难以实现最大化。提出一种基于路由热点循迹修正的WSN发射功率调度算法。设计了WSN节点路由热点循迹数据传输模型,对发射功率消耗能量模型采用一个高斯衰减信道建模,采用直线反馈线性化补偿方式对路由热点的偏移轨迹进行超负荷状态评估,采用贪婪算法生成一条多分簇路由链,对路由循迹轨迹进行修正,得到WSN优化发射功率的调度递推公式,实现能耗最佳的功率优化调度。实验结果表明,采用该优化调度方法,在准确实现热点循迹修正,传输功率较传统方法稳定,波动较小,WSN可靠性和生存性增强。     

基于链路同态解析的WSN路由选择算法

通过优化无线传感器网络(WSN)的路由选择算法,实现负载均衡,节省WSN节点的能量开销。传统的路由选择算法使用基于汇聚节点随机链路分析的路由选择算法,控制网络中节点的密度实现路由选择,算法受到外界干扰较大,性能不好。提出一种基于链路同态解析的WSN路由选择算法。设计WSN节点的能量调度算法,提取网络传输的数据多路复用器输出端口的数据,找到经过最短路径数目最多的边并将它从网络中移除,采用能量剩余度同态解析模型,把WSN的能量节点变换到链路同态解析波束域中,实现WSN路由选择算法改进,实现WSN节点的能量调度,提高WSN的负载均衡能力。仿真结果表明,该算法能优化WSN的路由选择,节点的平均能量消耗最低,提高了WSN的可靠性和生存周期。     

基于负载-功耗特征测试的WSN配网路由修复方法

为了增强无线传感网络(WSN)的自适应性,降低WSN功耗,需要进行配网路由修复。传统的路由修复算法采用能量感知模型,设置负载平衡的CTP路由协议估算剩余能量,算法没有考虑路由最大角度的负载平衡问题,路由修复性能不好。提出一种基于负载-功耗联合特征测试的WSN配网路由修复算法,设计了基于ICTP协议的WSN网络模型框架,综合考虑簇头的剩余能量及其与Sink的距离对它的生命周期的影响,进行路由选择设计,采用负载-功耗联合特征测试方法,实现WSN配网路由修复改进。实验结果表明,该算法进行WSN路由修复设计,节点剩余能量方差一直维持在最低,有效地均衡了网络负载,平衡了网络能量消耗,节点生存性较大,提高能量的有效利用率。     

剩余能量相干均衡分簇能耗双阈值分配算法

在计算机多分簇任务执行中,由于初始能量有限,需要对网络分簇能耗进行优化分配,提高任务执行效率。提出基于剩余能量相干均衡的网络分簇能耗双阈值分配算法,算法考虑了节点当前能量、簇成员数量、簇首与节点间距离,设计了能耗指导的分布式网络能量采集和消耗均衡模型,采用收敛性度量值进行路由分配,实现能耗的双阈值分配,在系统的全局任务调度中心将所有任务进行融合,输入系统总调度器,设计剩余能量相干均衡算法,构建能耗分配的双阈值模型,实现网络分簇能耗双阈值分配。实验结果表明,算法能够降低任务调度关键路径延时,提高low-Vt单元使用率,降低相干功耗,形成最优化能耗管理输出,使得系统更加稳定。     

矿井长直巷道中WSN的LEACH路由协议研究

LEACH路由协议具有层次化、自组织分簇的优点。本文针对矿井长直巷道环境下LEACH协议的不足,提出一种可靠的能量均衡路由算法LEACH-TLLEB。该算法采用线性网络拓扑结构合理部署Sink节点,局部区域节点结合位置均衡和能量均衡选举簇头。仿真结果证明,该算法改善了矿井下长直巷道WSN网络的可扩展性和能耗不均衡等问题,延长了网络的生命周期。     

基于反馈约束改进蚁群算法的网络路由优化

通过优化网络路由,提高网络的拓扑性能,实现网络的能量平衡。传统的网络路由算法采用能量平衡环形路由算法,出现网络能耗不均衡。提出一种基于反馈约束改进蚁群算法的网络路由优化方法。采用区域分割处理办法,得到分簇路由任务概率随机分布模式下的置信概率,通过蚁群反馈约束,提高信息正确传输的概率,根据贝叶斯定理,得到路由现成路由子节点定位和扑救路径方位置信度的递归计算式,实现网络路由优化。仿真实验表明,算法能有效提高网络信息正确传输的概率,可靠性较高,几乎能达到无失真传输,随着路由跳数的增加,设计的路由算法的优势愈发明显,提高了信息传输的通信质量。     

基于链路不对称性预测的机会网络路由设计

机会网络的混合路由优化设计可以有效降低冗余开销,提高数据传递成功率。传统方法采用链路代价评估和能量节省延迟容忍算法实现机会网络的路由设计,当在移动自组织网络中出现节点稀疏化调度下链路具有不对称性,降低了路由分配质量。提出一种基于改进的OLSRv2算法的链路不对称性预测控制机会网络混合路由优化算法,定义机会网络中混合置信因子概念,研究路由优化检验统计量的确定和判别系统的设计,通过OLSRv2算法引入了概率路由,在当前连通域的路由信息进行地址压缩得到最优传送概率值。仿真实验表明,采用该算法设计的机会网络路由进行网络通信,得到较小的控制开销,提高通信成功率,网络负载大幅降低。     

基于云计算技术的电力系统无线激光通信网络路由

为提高电力系统无线激光通信网络的数据传输质量、降低路由能量开销,提出基于云计算技术的电力系统无线激光通信网络路由算法研究。在云计算的框架下,构建一种节点间的能量消耗模型,基于云计算技术强大的运算能力,确定激光通信网络内有效的通信距离和节点位置;分析节点间的数据传输速率,预估激光通信网络中最优的总跳数,并选定能耗最低的后续节点,组成整条路径。仿真实验结果证明,提出的路由算法设计能够有效提高通信网络的数据传输质量、缓解网络时延,同时还可以降低节点能耗、延长无线激光通信网络的使用寿命。     

基于LEACH协议的WSN改进分簇算法的理论分析

基于LEACH协议,提出WSN改进分簇路由算法。该算法能根据节点的剩余能量和节点到基站的距离在无线传感器网络中选出簇头,再由接受信号的强度确定成簇规模不超过最大成员数的簇成员节点,并依据所选簇头的自身条件动态决定是否需要在簇内产生助理簇头,进而在需要的簇内选择合适的节点作为助理簇头。根据理论分析,改进算法能均衡网络负载,降低网络能耗,延长网络生存时间以及提高网络运行周期。     

干扰避免的认知无线电图着色频谱分配算法

对传统的认知无线电图着色频谱分配算法进行了改进。在分配过程中动态更新干扰矩阵,使更多节点共享同一频段而不相互干扰,以此提高频谱利用率,对授权用户的干扰也可通过发射功率门限的设置来避免。在此基础上算法以最大化认知网络吞吐量为优化目标,仿真结果表明,采用新算法后,在无干扰条件下的网络吞吐量和信道传输速率都明显高于同类算法。     

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.     

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.     

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     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.