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51.
VPDN企业端解决方案 总被引:1,自引:0,他引:1
从虚拟专用拨号网(VPDN)结构的基本原理、隧道协议、认证方式等方面概述了中国联通开展VPDN业务的实施步骤和解决VPDN企业端的5种模式,并介绍了中国石油天然气管道电信公司实现VPDN企业端的具体方案。 相似文献
52.
Soft sediments from the Detroit River were analyzed for the USEPA priority pollutants to generally characterize contaminant distribution. Forty-three were detected. Highest heavy metal concentrations were found in the Trenton Channel and immediately downstream of Grosse Ile. They ranged from an area mean (N = 2) of 0.19 mg/kg mercury to 338.7 mg/kg zinc (dry weight). Polynuclear aromatic hydrocarbons ranged from 0.1 mg/kg to 38.8 mg/kg (mean, N = 2) with the highest levels near Grosse Ile. PCBs ranged from 0.015 mg/kg to 1.7 mg/kg (mean, N = 2). Organochlorine pesticides were not detected except for a trace of heptachlor in one sample. Sediment contamination in the Detroit River is widespread with higher concentrations on the U.S. side downstream of the Rouge River and in the Trenton Channel. The significance of these in-place pollutants to biota and as a source to Lake Erie is still unknown. 相似文献
53.
54.
In this paper we propose a new protocol called time-space label switching protocol (TSL-SP) in optical burst switching (OBS), and define the terms time-space label (TSL) and time-space routing (TSR). An important concept of response time is introduced in the time label mechanism. The TSL-SP is a new technology that can quickly and efficiently forward data with a label on the optical networks. A two-dimension label switched path (TD-LSP) can be set up, that is maintained and deleted by the TSL-SP. For clearly illuminating the operation principles of the TSL-SP, we propose a new approach of orthogonal time-space coordinates in which the vertical coordinate is the space label and the horizontal coordinate is the time label. The proposed TD-LSP can dramatically reduce the routing failure probability and greatly improve the link network efficiency compared with other signaling protocols. Moreover, we define the time-space label control plane that can achieve the higher efficiency. When the TSL-SP is applied to networks, switching performance can be improved by two orders compared to the switching performance with the conventional OBS signaling protocols. The fundamental goal of TSL-SP is to band the signaling and routing functions together closely. Also, the TSL-SP can reduce the complexity of the network, support automatic service offering, and provide traffic engineering. 相似文献
55.
XU Li~ 《中国邮电高校学报(英文版)》2004,11(4)
MANET(Mobile Ad Hoc Network)is a collection of wireless mobile nodes forming a temporary communica-tion network without the aid of any established infrastructure or centralized administration.The lifetime of a MANETdepends on the battery resources of the mobile nodes.So energy consumption may one of important design criterions forMANET.With changing the idle model to sleep model in the grid environment,this paper proposes a new energy-awarerouting protocol.Performance simulation results show that the proposed strategy can dynamic balance the traffic load in-side the whole network,extend the lifetime of a MANET,and without decreasing the throughput ratio. 相似文献
56.
Giovanni Giambene Enrico Zoli 《International Journal of Satellite Communications and Networking》2003,21(2):199-225
In this paper, we investigate a packet access scheme that is able to support mixed traffics in the presence of high propagation delays. Referring to a Time‐Code Division Multiple Access air interface, we propose a Medium Access Control (MAC) protocol based on a random access scheme. A successful attempt grants the use of a slot‐code resource. This protocol is named Adaptive Time Code‐Packet Reservation Multiple Access (ATC‐PRMA), since the access parameters are changed, depending on the traffic load conditions, so as to fulfil Quality of Service requirements. Numerical examples are carried out for the Low Earth Orbit (LEO)‐Mobile Satellite System (MSS) scenario, but all these considerations could be applied to High‐Altitude Platform Stations (HAPSs) as well. In both cases, high propagation delays prevent an immediate feedback to users. An analytical approach is proposed to study the stability of our MAC scheme. Accordingly, we define a criterion for optimizing system performance. The predicted ATC‐PRMA behaviour is supported by simulation results. Finally, we show the performance improvement of ATC‐PRMA with respect to a MAC protocol not employing adaptive parameters. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
57.
Castonguay Louis G.; Schut Alexander J.; Aikens Deane E.; Constantino Michael J.; Laurenceau Jean-Philippe; Bologh Laura; Burns David D. 《Canadian Metallurgical Quarterly》2004,14(1):4
This study is a preliminary investigation of an integrative treatment aimed at improving the efficacy of cognitive therapy (CT) for depression. The development of the treatment protocol was based on process findings, which suggested that strategies used in CT to resolve alliance ruptures may actually exacerbate problems in the therapeutic relationship. The protocol integrates, within the traditional CT treatment manual, procedures to repair alliance ruptures that are derived from or consistent with humanistic and interpersonal therapies. Although conducted by inexperienced therapists, the integrative treatment led to greater improvement than a waiting-list condition. The results also compare favorably to previous findings for CT. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
58.
Michael Angling 《International Journal of Project Management》1985,3(2):114-120
Where there are a large number of projects competing for a limited pool of resources, projects have to be assigned priorities to determine which should proceed and which should be curtailed. The traditional economic procedures for assessing the relative priority of projects are reviewed, and alternative methods of ranking projects are suggested, with particular emphasis on methods that are inexpensive and easy to use. 相似文献
59.
自治Agents的面向服务的协商模型 总被引:3,自引:0,他引:3
提出了一个基于自治Agents的面向服务的协商模型。模型主要包括两大模块:首先定义了一系列的战略和战术过程,使得Agents可以产生初始建议,评价对方的建议,以及在此基础上做出反建议;其次,定义了两个层次的Agent通信机制。二者相辅相成,实现了Agents间合作的动态形成和随机协调,使得Agents可以承担因环境的不确定性而需动态协作的复杂任务。 相似文献
60.
本文先从软件理论的角度对安全协议分析语言CPAL的语法和语义进行分析,指出这种语言控制流的缺陷,在语法和语义方面给出CPAL语言的完善方案,并从信息安全中的协议的广泛性方面说明其必要性。 相似文献