9～500kHz PLC信道噪声测量与分析

为研究智能用电9～500kHz PLC频段内信道噪声随频率和地点的变化特性,讨论了窄带噪声测量方案和噪声功率谱分析方法,并对4个地区的低压电力线信道噪声进行测量和分析。分析结果表明在9～500kHz频段内的噪声幅度从十几db到上百db之间变化,总体上随频率的增加呈下降趋势;9～250kHz之间背景噪声比较严重;同一地点A相、B相、C相的信道背景噪声相对一致,脉冲噪声不同。     

QoS guarantee in telecommunication networks: technologies and solutions

The aim of this paper is to show the effect of the presence of specific management functions within a network that offers quality of service (QoS). The objective is not privileging a particular technology but to highlight the importance to know which control functions a solution may use, which performance limits the functions have and what can be a realistic user expectation. The paper focuses on the meaning of QoS and on the applications requiring quality, then describes QoS solutions including transport technologies, QoS‐oriented technologies, parameters and management functions. In more detail, the effect on QoS provision of the following issues is investigated and discussed concerning the possibility (or not) to aggregate and differentiate traffic, the implementation of call admission control and of traffic filtering to limit flows to their committed rates. Again, the conclusions should not be considered a merit mark about technology, but only an investigation about: what users and customers should expect by the technologies using specific control functions evidencing that the real limitations are not imposed by a specific technology, whose features may be changed and extended, but by the application of control functions that can guarantee requirements' matching. Copyright © 2004 John Wiley & Sons, Ltd.     

Metaproject analysis: multiagent virtual project networks for strategic decisions in preplanning

The paper describes metaproject analysis, a new scenario method. It is a systemic methodological aid for decision making in midterm and long-term strategic planning. It uses advanced techniques of modelling and simulating stochastic project-planning networks. This methodological approach describes the evolution from present to future (towards the achievement of a preestablished goal, for example the market introduction of a new public service or system) as a multiagent and cooperative virtual project plan (metaproject). Such a metaproject must be formally translated into a metaproject network (scenario), assembling the significant activities of all the agents involved, which are supposedly cooperating. An example case study related to telecommunications and a home-banking service is presented.     

面向21世纪的中国电信发展

本文介绍了我国电信事业的发展现状，面临的机遇和挑战，以及未来的发展目标。     

基于电力线通信的信息家电网络系统

在分析电力线通信技术的基础上,指出了电力线通信用于信息家电联网所具有的明显优势.提出了基于电力线通信技术构建信息家电网络平台的设想,给出了网络系统结构模型,并详尽阐述了网内接口协议.     

车载自组网与通用移动通信系统混杂网络技术

当车载自组网(Vehicular ad-hoc network,VANET)网络节点访问Internet获取服务时,传统的无线接入点因其覆盖范围有限和地理位置的局限性限制了VANET与Internet的无缝互连。基于OPNET仿真平台,本文扩展了传统的移动自组网网关,新网关支持与通用移动通信系统(Universal mobile telecommunications system,UMTS)核心网建立连接,形成混杂网络,使VANET网络中节点可以通过UMTS网络访问Internet,依托UMTS网络覆盖范围的优势,弥补VANET网络的不足。     

New approach to return-oriented programming exploitation mitigation

Preventing software exploitation is an incredibly important goal for cyber security professionals, and huge amounts of time, effort, and money are devoted to this cause worldwide. A key stage of the exploitation process is gaining control of the execution flow of a target process so as to redirect it to the attacker’s illicit shellcode; most of the exploit mitigations currently in use are targeted at increasing the difficulty of this act. This article presents a new method for preventing control flow hijacking that provides a more robust defensive posture than existing options and is achieved by dereferencing function and return pointers to evaluate their contents rather than the extant approach of evaluating the pointers themselves.     

湖南省各市州邮电业务年度发展水平的因子分析

文章对湖南省各地州市2006年的邮电业务发展情况进行综合评价,建立了评价指标体系,用因子分析法对原始数据进行数学处理。根据不同因子代表的业务类别对各市州进行排名,分析各市州在不同业务类别上的发展水平及发展优势,并针对这些特点就如何进一步提高湖南省邮电业务提出一点建议。     

电信企业出勤管理系统设计与实现

为了简化电信企业内部的出勤管理,提高部门工作效率,在对相关需求进行详细分析的基础上,设计和实现基于．NET平台的电信企业出勤管理系统,包括用户管理、业务的申请、业务的审核等功能模块,详细介绍其主要技术特点和模块功能。     

A decomposition algorithm for the ring spur assignment problem

This paper describes the ring spur assignment problem (RSAP), a new problem arising in the design of next generation networks. The RSAP complements the sonet ring assignment problem (SRAP). We describe the RSAP, positioning it in relation to problems previously addressed in the literature. We decompose the problem into two IP problems and describe a branch‐and‐cut decomposition heuristic algorithm suitable for solving problem instances in a reasonable time. We present promising computational results.