IPv4/IPv6混合网络中一种过渡拓扑发现技术

由于IPv4网络的广泛影响,其向IPv6网络的过渡需要很长一段时间.在此期间,IPv4协议和IPv6协议长期共存,过渡网络的管理是亟待解决的重要问题.针对此问题,分析了拓扑发现的一般方法和在IPv4/IPv6混合网络环境下拓扑发现需要解决的问题,提出了一种解决方案.方案综合了SNMP网络管理模式和traceroute6网络管理技术,解决了匿名路由器和交叉链路的发现等问题.实验表明该方案工作效率较高,结果令人满意.     

A Multiobjective Optimization Algorithm for QoS-Aware Path Selection in DiffServ and MPLS Networks

Introduction The enlargement of the Internet user commu-nity has generated the need for IP-based applica-tions requiring guaranteed quality of service (QoS)characteristics. For providing per-flow serviceguarantees without a per-flow state in the corerouters, the integration of DiffServ and multi-pro-tocol label switching (MPLS)[1]architecture hasbeen proposed. The MPLS architecture provides adistributed way for resource reservation and QoSpath setup through the use of a Label Distribut…     

CDMA 网络中基于 QoS 保证的呼叫接纳控制策略

基于CDMA（code division multipleaccess）系统接纳控制（call admission control，CAC）机制没有完全考虑各种多媒体业务的现状，研究了CDMA系统中剩余容量的计算方法，采用更加符合目前无线多媒体网络中业务实际情况的业务模型，给出了一种针对多媒体业务的基于QoS（quality of service）保证的动态CAC算法．分析与仿真结果表明，该算法在保证各种业务QoS要求的情况下，可以显著改善CDMA系统的呼叫等待延时和中断率等性能，提高系统资源的利用率．     

A QoS aware service composition protocol in mobile ad hoc networks

A novel decentralized service composition protocol was presented based on quality of service (QoS) for mobile ad hoc networks (MANETs). A service composition in MANETs is considered as a service path discovery in a service network. Based on the concept of source routing, the protocol integrates route discovery, service discovery and service composition and utilizes a constrained flooding approach to discover the optimal service path. A service path maintenance mechanism was exploited to recover broken service paths. Simulation experiments demonstrate that the proposed protocol outperforms existing service composition protocols.     

A simulation study of service differentiation for the bandwidth request scheme in fixed IEEE 802.16 network

Various flexible mechanisms related to quality of service (QoS) provisioning have been specified for uplink traffic at the medium access control (MAC) layer in the IEEE 802.16 standards. Among the mechanisms, contention based bandwidth request scheme can be used to indicate bandwidth demands to the base station for the non-real-time polling and best-effort services. These two services are used for most applications with unknown traffic characteristics. Due to the diverse QoS requirements of those applications, service differentiation (SD) is anticipated over the contention based bandwidth request scheme. In this paper we investigate the SD with the bandwidth request scheme by means of assigning different channel access parameters and bandwidth allocation priorities at different packets arrival probability. The effectiveness of the differentiation schemes is evaluated by simulations. It is observed that the initial backoff window can be efficient in SD, and if combined with the bandwidth allocation priority, the SD performances will be better. Foundation item: the National Basic Research Program (973) of China (No. 2005C13321804)     

mTOR/P70S6K信号通路在宫颈癌组织中的表达及其临床意义

目的 研究mTOR/P70S6K信号通路中哺乳动物雷帕霉素靶蛋白(mTOR)及其底物激酶(P70S6K)在宫颈癌中的表达及其在宫颈癌发生发展中的作用.方法 用RT-PCR和免疫组织化学法检测正常宫颈、宫颈癌中mTOR和P70S6K激酶的表达.结果 与正常组织相比,宫颈癌中的mTOR和P70S6K激酶在mRNA及蛋白水平表达均显著增加(P<0.05),且两者的表达具有显著的正相关性(r=0.746,P<0.001).结论 mTOR/P70S6K信号转导通路在介导宫颈癌的发生、发展的过程中起到重要作用.     

公路交通服务能力的绿色安全指标研究

国际上公路交通服务能力皆以道路拥堵情况(V/C 值)及行车顺畅程度为评估 标准,缺乏对交通安全潜在社会成本、时间成本及环境保护的测量.根据国际社会对绿色 经济、绿色交通运输的重视与发展趋势,本文以台湾电子收费系统的数据为基础,针对不 同交通流需求量、路段平均行驶速率衍生的时间成本与污染排放、交通安全等因子,分别 构建出行时间延滞成本、碳排放增量成本、潜在肇事概率成本等3 个参数指标,利用这3 个指标构建综合型绿色安全交通服务指标(Green and Safety Index for traffic levels of service, GSI),作为划分交通服务水平的评估标准,并通过实时在线软件,提供出行者道路 出行延滞、碳排放及安全等社会成本信息.