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1.
《科技通报》2015,(10)
设计高速网络流路由修复算法,提高网络的生命周期,降低路由节点能耗。传统的路由修复算法采用阈值分割路由冲突分解算法,采用阈值分割判断实现路由修复,无法有效满足高速网络流路由修复的应用环境。提出一种基于断点损耗预测的高速网络流路由修复方法。计算通信节点的衰减性能,绘制出符合高速移动环境移动节点衰减曲线,根据欧氏距离公式计算出随机分布的路由节点的路径链接的稳定性,对多角度系数进行修订,采用断点损耗预测方法,进行功耗损失修订,实现路由修复。仿真实验表明,该算法实现高速网络流路由修复。有效地控制簇头的数量和分布、节约能量、均衡网络负载,提高了高速网络流路由的生命周期,单个节点能耗大幅降低,在高速移动大规模网络流维护和路由控制优化中具有较好的应用价值。 相似文献
2.
基于链路同态解析的WSN路由选择算法 总被引：3，自引：0，他引：3
《科技通报》2015,(8)
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。 相似文献
3.
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。 相似文献
4.
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。 相似文献
5.
提出了一种改进型LEACH算法。将能量因素加入到阈值计算公式中,均衡了节点的能耗。同时,针对重要参数难以通过实验的方式进行评估的问题,基于改进型LEACH算法建立了无线传感器煤矿安全监控网络的仿真模型,利用NS2仿真平台对其重要参数进行了仿真分析。分析结果表明,改进型LEACH算法能均衡节点的能量消耗,有效延长网络的运行时间,并且,通过仿真实现了系统模型参数的优化,验证了安全监控网络实施的可行性。 相似文献
6.
提出一种面向无线Ad Hoc与传感器网络的基于自适应能量阈值的按需节能组播路由协议EMRP.该协议能根据网络能量状态和节点保护比例,自适应地确定能量保护阈值.在按需构造组播路由树的过程中,该阈值抑制网络中能量过低的节点参与组播,从而实现网络能耗均衡.EMRP同时引入目标驱动的策略,以尽量减小组播结构的规模、降低组播代价.EMRP协议执行过程中,不要求节点保存任何全局或局部网络拓扑信息,开销低,实现简单.仿真结果表明,与已有工作相比,EMRP协议能大大降低组播路由的每分组传输能耗,显著延长网络寿命. 相似文献
7.
根据无线传感网络中簇头点生成过程中的多径能量特性,提出一种基于自适应均衡抵消的相位检波能量检测算法。建立无线传感器网络信号与信道系统模型,设计无线传感器网络信道自适应均衡算法,采用横行型自适应FIR滤波器进行自适应降噪滤波处理。使用相位检波方法对UWB无线传感器网络通信信道进行能量检测和优化设计。实验结果表明通过自适应相位检波能量检测方法,能最大程度上削弱无线传感网络信道慢衰落影响,降低网络功耗,提高能量检测性能和信道传输效率,实现了无线传感器网络信道优化设计。 相似文献
8.
基于对LEACH算法的研究,提出助理簇头ASCH算法。该算法能够在无线传感器网络中,根据簇头节点所处的地理位置、剩余能量及簇内成员节点数目,动态决定是否需要在簇内产生助理簇头,并在需要产生助理簇头的簇内选择合适的节点来减少簇头通信能耗,同时解决某些簇头与基站通信可能存在困难的问题,从仿真结果可见此算法能有效均衡及降低网络能耗,达到延长网络的生存时间的目的。 相似文献
9.
由于WSN节点能量有限,为了均衡整个网络的能耗,延长WSN的生命周期,针对LEACH算法,提出一种改进的协议。该协议基本思想以LEACH算法为基础,结合节点的能量、位置及其分布密度,修改了簇头选举公式;在多跳传输时综合考虑下一跳节点的剩余能量及其到基站的距离。 相似文献
10.
Linux虚拟服务器(LVS)是一个虚拟的服务器集群系统。在大功率干扰下,LVS集群的抗扰动性能不好,无法有效实现IP负载均衡和任务调度。提出一种基于功率自激的大功率干扰下LVS负载均衡集群抗扰动算法。采用自适应神经模糊系统网络动态干扰监测模型构建网络信息鲁棒性评价模型及Linux嵌入式用户信任感知网络信息信任度评价,计算MAC层两个模糊概念之间的相似度。得到大功率干扰监测数学模型,假设干扰信号表现为一种动态随机噪声信号,实现对大功率干扰下的LVS网络的扰动容错方案设计,对簇节点的接收信号强度(RSSI)信息没有合理开发应用,在簇头生成过程中形成的帧没能实现自适应均衡处理,分析节点之间发射和接收信号的耦合效应,需要实现算法上的改进。仿真结果表明,该算法有效实现IP负载均衡和任务调度,延迟了网络生命周期,提高Linux虚拟服务器的抗扰动性能。 相似文献
11.
A research 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 in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
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. 相似文献
12.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
13.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
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. 相似文献
14.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
15.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US 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 the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
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. 相似文献
16.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
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. 相似文献
17.
Active biological molecules 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 therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
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. 相似文献
18.
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. 相似文献
19.
Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
20.
Puay Tang 《The Information Society》1998,14(1):19-31
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. 相似文献