Integrating Differentiated Services with ATM

IP in the edge and ATM in the core are commonplace in today's internetworks. The IETF has proposed a new Quality of Service (QoS) mechanism namely Differentiated Services (DiffServ) for IP networks. On the other hand, QoS is an inherent feature in ATM. It is imperative that IP and ATM QoS interoperate efficiently to provide an end-to-end service guarantee. DiffServ provides a class of service named Assured Forwarding (AF) that does not exactly correlate to any of the service categories offered by ATM. AF is targeted towards a range of applications, such as real-time (rt) that do not require a constant bit rate service provided by Expedited Forwarding, and other non-real-time (nrt) applications that expect a service better than best effort. In this paper we propose the mapping of AF to the Variable Bit Rate (VBR) service category in ATM. VBR is suitable because it is available in the form of rt-VBR and nrt-VBR and could be translated appropriately based on the applications. The mapping is implemented and verified using the LBNL Network Simulator. The results of the experiments show that VBR is a better match for AF than any other service category in ATM.     

University-based graduate training of community agency workers: A pilot collaboration project.

The 1996 Welfare to Work Mandate has had a significant impact on the lives of families that use public assistance. What role can university counseling and psychology training programs play in the facilitation of this mandate that is intended to return welfare recipients to work? The Welfare Reform Act is discussed in relation to an innovative program that provides graduate-level training for bachelor's-level social service workers to meet the challenges of new service-delivery mandates. Relevance of this collaborative effort to professional psychology is explored, and implications for training master's-level graduate students are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Case study of safe lowering of an in service gas pipeline

This paper describes an experimental investigation carried out involving instrumentation, measurement and monitoring of stresses in a large diameter gas pipeline during its lowering operations. It also highlights the ingenious techniques developed and adopted to overcome the difficulties pertaining to long leadwires, measurement of existing strains on the curved surface of a pipeline and protection of strain gauge installations. These novel methods were used to ensure smooth and proper functioning of strain gauge instrumentation even under the severe field conditions at site for more than two weeks, till the lowering operations and pipeline monitoring was successfully completed.     

A comparison of congestion control and time slot algorithms in Internet transmission performance

The characteristics of TCP and UDP lead to different network transmission behaviours. TCP is responsive to network congestion whereas UDP is not. This paper proposes two mechanisms that operate at the source node to regulate TCP and UDP flows and provide a differential service for them. One is the congestion‐control mechanism, which uses congestion signal detected by TCP flows to regulate the flows at the source node. Another is the time‐slot mechanism, which assigns different number of time slots to flows to control their flow transmission. Based on the priority of each flow, different bandwidth proportions are allocated for each flow and differential services are provided. Simulation results show some insights of these two mechanisms. Moreover, we summarize the factors that may impact the performance of these two mechanisms. Copyright © 2001 John Wiley & Sons, Ltd.     

计算网格环境下以QoS为指导的启发式任务调度

实现用户的服务质量QoS是网格的一个重要特征．网格环境下以服务质量为指导的任务调度是一个非常复杂且具有挑战性的问题，特别是在用户的任务具有多种QoS需求的情况下。利用效用函数对用户的多种QoS进行建模．提出了一个同时兼顾任务完成时间和用户服务质量的目标函数。在此基础上提出了一种计算网格环境下针对一组具有QoS需求的相互独立的计算任务的启发式调度算法。模拟实验结果显示，该算法能较好的满足不同用户的需求并提升系统资源的利用率。     

信息基础设施:支撑电信业务转型的基础平台

本文首先分析了信息基础设施在现代电信运营过程中的重要作用,进而阐明电信支撑系统和信息基础设施的关系,指出影响信息基础设施建设的关键技术和趋势.最后,归纳总结了信息基础设施建设的成功要素.     

对于IPv6网络中服务质量的研究

随着Internet的迅速发展,新型的网络应用对QoS的需求日益迫切,为了使网络能够支持已有的和新出现的多媒体服务与应用,保证通信与服务质量,让网络运营商控制网络资源及其使用,对于QoS的研究越来越重要。首先介绍QoS的相关概念,然后比较IPv4和IPv6对于服务质量的不同支持并具体研究IPv6下对于支持QoS机制的改进。     

浅谈信息服务在招投标工作中的重要地位

在建设工程招投标规范化建设的各项基本对策中,工程招标信息服务占有很重要的地位,本文即基于此做一些有益的探讨。     

房地产项目开发建设中住宅整体质量问题探析

商品住宅的质量关系着国家的未来和房地产业的兴旺,本文试图对住宅产品的质量现状、问题及成因进行分析,在此基础上提出进一步提高品住宅整体质量的看法:     

基于Web Service的分布式电子商务系统设计与实现

文章仔细分析了现有电子商务系统在构架上存在的不足和远程访问协议上存在的局限性，刨设了基于Web Service的分布式构架。该构架充分利用了Web Service的优势，将商务事件逻辑分布在多台服务器上，提高了系统的可靠性、稳定性、可扩展性以及维护性。在现有商务系统设施和技术平台的基础上，该系统充分利用松散耦合的服务程序集成了多种业务活动，初步构建了大型电子商务系统的架构。