LTE系统中一种利用DRX降低UE功耗的视频流调度方法

提出一种利用DRX(discontinuous reception)降低UE(user equipment)功耗的视频流调度方法,该方法在保证数据包时延要求的同时,减少了InactivityTimer的开启次数,增加了UE的休眠时间.仿真结果表明,相比已有的DRX机制下的实时业务调度方法,该方法可以在丢包率相同的情况下,显著降低UE的功耗.     

入侵破坏后的网络信道优化通信模型研究

为了提高入侵破坏后网络信道通信性能,按照入侵破坏后网络信道的衰减特征,融合自适应比特以及功率划分方法,提出基于节点可信度子信道等效改进的网络衰减信道通信优化方法,采用基于节点可信度的信道分配方案,对关键链路优先分配信道,降低链路冲突,实现网络通信信道的初步优化,再通过子信道等效改进方法,在信道已经被入侵破坏的基础上,在传递总比特数一定时,依据发送功率最小化模型,综合分析特性相同或相近的子信道,降低已经被入侵破坏后的网络信道通信信令负荷,完成被破坏网络信道通信的再次优化。仿真结果表明,该方法可有效降低被破坏网络链路冲突率和数据丢包率,提高了衰减网络通信性能。     

基于断点损耗预测的高速网络流路由修复方法

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。     

置信因子链路不对称对抗通信网标准化控制

无线通信信息传输和利用面临丢包率高,安全性受限等难题,通信网络标准化服务控制是互联网与卫星通信互联可靠传输的保证。提出一种基于置信因子链路不对称对抗的通信网标准化服务控制方法,解决网络堵塞、延时、丢包以及泄密等问题,实现网络安全传输和利用。仿真测试表明,新的通信网服务控制方法能使网络负载大幅降低,丢包率降低,用户成功接收率提高。有效解决了网络堵塞、延时、丢包以及泄密等网络不安全因素难题。     

802.11s无线Mesh网络中协作多样性感知的路由度量和协作路由协议

提出了802.11s无线Mesh网络中协作多样性感知的路由度量,并提出了适应无线Mesh网络特点的协作式路由协议(CDARP)与协作媒体访问控制协议(CMAC).通过构建协作虚拟节点、计算协作链路度量,CDARP-CMAC能够选择最合理的路径进行协作数据传输.实验结果表明,与最优路径的协作机制相比,CDARP-CMAC协议提高了网络有效吞吐量5％～13％;同时降低了数据包丢包率5％～10％.     

基于非线性主动队列管理算法的计算机网络拥塞控制研究

针对主队队列管理算法中丢包率与排队长度的关系进行分析,研究发现主队队列管理算法在丢包的过程中具有不够合理的部分,即在最大阈值和最小阈值处出现丢包异常的现象。为了解决这一问题,本文建立了新的数据处理模型,用新模型对丢包率进行分析,以二次函数的形式构建了新的丢包率计算公式,并通过该公式对网络拥塞中队列的丢包算法进行优化,从而使得主队队列管理算法的丢包更加合理,使得系统的公平性与稳定性得到提升,保障了系统的运行。     

基于优先级调度网络冲突避免模型仿真

随着光通信技术近年的迅猛发展,多路由网络不断改善,目前多路由网络构建技术成熟,具有较好的保护倒换机制,以满足广泛应用者的需求。现阶段的多路由网络平台系统只能单一静态运行,且在调度通信任务时,无法选择优先级并产生总线冲突,不能降低能量消耗及节省时间,影响了多路由系统的发展速度。为此,提出多路由网络总线冲突避免调度模型,通过在时间调控下调度通信任务与计算任务来降低能量消耗,有效的节能调度可避免总线冲突,并在时间限制下实现节能消耗。仿真实验表明,多路由网络总线冲突避免调度模型,实现了任务的目标优先级通信任务与任务的协同调度及能量的低消耗性能,为避免多路由网络系统总线冲突提供了帮助。     

二维自由粒子群图像阈值分割算法

根据二维图像阈值分割和ITPSO的理论,提出2D-FPSA。2D-FPSA适用于任何形式的二维图像信息。与传统的二维算法不同,该算法不需要准则函数,通过一个自由运动的粒子群得到最优阈值。实验结果表明,2D-FPSA是稳定、快速和有效的二维图像阈值分割算法。其分割结果优于ITSPO。     

基于3G网络视频传输的一种QoS控制方法

针对3G网络视频传输,提出一种应用层的服务质量(quality of service,QoS)控制方法.该方法采用线性预测算法计算丢包率,并引入严增松减等步长拥塞控制算法对视频输出码率进行自适应调节.实验结果表明,端到端延迟时间和延迟时间抖动等QoS控制参数均符合通信行业对实时业务的指标要求,同时网络利用率也得以提高.该QoS控制方法适用于3G网络视频传输,具有良好的可行性和实用性.     

基于预先地址生成和绑定的异构网络FMIPv6协议

针对异构网络切换中FMIPv6协议存在高延时高丢包,无法满足实时业务对服务质量要求的问题,提出了一种能预先进行地址生成和绑定的FMIPv6协议——PAGB-FMIPv6（Proactive Address Generation and Binding for FMIPv6）。该协议在FMIPv6的基础上,采用预先生成可用转交地址、提前进行新转交地址的绑定更新方法,消除切换过程中重复地址的检测操作,减少新转交地址绑定更新延迟,增加预应式切换的可能性,从而减少切换延迟和丢包。仿真结果显示,新协议在切换延迟、丢包方面优于FMIPv6。     

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