运用SOCKS V5/TLS协议构建VPN的研究与实现

提出了在ＳＯＣＫＳ防火墙之间建立ＶＰＮ的架构与技术的思想，利用ＳＯＣＫＳ Ｖ５对认证方法的可扩充性，采用ｘ，５０９规范与数字签名实现了ＳＯＣＫＳ防火墙之间的证书及身份验证，并运用ＴＬＳ协议协商数据加密算法与密钥对其数据进行加密传送，介绍了其关键技术的实现。     

Flexible Servers in Understaffed Tandem Lines

We study the dynamic assignment of cross‐trained servers to stations in understaffed lines with finite buffers. Our objective is to maximize the production rate. We identify optimal server assignment policies for systems with three stations, two servers, different flexibility structures, and either deterministic service times and arbitrary buffers or exponential service times and small buffers. We use these policies to develop server assignment heuristics for Markovian systems with larger buffer sizes that appear to yield near‐optimal throughput. In the deterministic setting, we prove that the best possible production rate with full server flexibility and infinite buffers can be attained with partial flexibility and zero buffers, and we identify the critical skills required to achieve this goal. We then present numerical results showing that these critical skills, employed with an effective server assignment policy, also yield near‐optimal throughput in the Markovian setting, even for small buffer sizes. Thus, our results suggest that partial flexibility is sufficient for near‐optimal performance, and that flexibility structures that are effective for deterministic and infinite‐buffered systems are also likely to perform well for finite‐buffered stochastic systems.     

数字出版发行平台的运营与功能整合

我国数字出版发行平台主要有传统出版机构主导型、传统发行机构主导型、技术服务商主导型、终端制造商主导型和网络运营商主导型等五种模式。我国数字出版发行平台还面临诸如平台数量不均、内容资源匮乏、平台封闭、读者不习惯、法律滞后等困境,应通过利益整合、平台整合、终端整合、跨行业整合、定制发售、完善盈利模式、加强出版法律法规建设等来解决。     

新的口令认证密钥协商协议

针对服务器泄漏攻击,给出了抵抗这种攻击的方法,提出了一个新的基于口令的认证密钥协商协议。在该方案中,用户记住自己的口令,而服务器仅仅存储与口令对应的验证信息。分析结果表明,该方案可以抵抗服务器泄漏攻击、字典攻击和Denning-Sacco攻击等,并且具有前向安全性等性质。     

Delphi程序对Powerpoint演示文稿操作的实现

介绍如何使用Delphi程序实现Powerpoint演示文稿的创建;幻灯片的插入、删除、移动;幻灯片对象属性值的设置、修改和读取;动画效果设置和幻灯片放映控制等操作的基本方法.     

面向网络的一种新分布式事务处理协议

提出了一种新的适合于当前网络环境，基于客户机／服务器应用方式及远程过程调用（ＲＰＣ）的分布事务处理模型及其实现协议。分析与实验表明它不仅满足网络中客户机／服务器应用的具体特点与要求，而且可以克服各种两段式提交协议中由于协调者故障造成的阻塞，同时避免了三段式提交等协议为解决阻塞而引起的开销过大，实现复杂等问题     

基于代理服务器的计费软件开发

针对广泛使用的基于代理服务器的局域网,利用VB语言开发了流量计费软件,给出了各个主要功能模块的详细程序设计流程,解决了“一台微机,多人上网”的计费问题,突出了只能基于IP地址计费的局限,实现了基于用户的费用计算。     

A characterization of probability distributions similar to the exponential

A concept of the lack-of-memory property at a given time point c > 0 is introduced. It is equivalent to the concept of the almost-lack-of-memory (ALM) property of the random variables. A representation theorem is given for the cumulative distribution function of such random variables as well as for corresponding decompositions in terms of independent random variables. It is shown that a periodic failure rate for a random variable is equivalent to the ALM property. In addition some properties of the service time of an unreliable server are observed.     

A semi-markov approach to stochastic compartmental models

In the past, various methods using either differential equations or differential-difference equations have been used to analyze stochastic compartmental models. In this paper a semi-Markov process approach is used to provide a framework for analyzing such models. The distribution function of the number of particles in each of the compartments is derived along with the stationary distributions. Various models found in the literature arising from biological and reliability applications are analyzed here using the semi-Markov process technique.     

Stationary analysis of a BMAP/R/1 queue with R-type multiple working vacations

We consider an infinite-buffer single server queue with batch Markovian arrival process (BMAP) and exhaustive service discipline under multiple working vacation policy. The service time during a working vacation is generally distributed random variable which is independent of the service times during a normal busy period as well as the arrival process. Duration of service times during a normal busy period and duration of working vacation times follow the class of distributions whose Laplace-Stieltjes transforms are rational functions (R-type distributions). The service time during a normal busy period, working vacation time, and the service time during a working vacation are independent of each other as well as of the arrival process. If a working vacation terminates while service is going on for a customer at head of the queue in vacation mode then, the server switches to normal mode and the customer at head of the queue is entitled to receive a full service time in the normal busy period irrespective of the amount of service received by the customer at head of the queue during the previous working vacation period. We obtain system-length distributions at various epoch, such as post-departure, pre-arrival, arbitrary, and pre-service. The proposed analysis is based on the use of matrix-analytic procedure to obtain system-length distribution at post-departure epoch. Later, we use supplementary variable technique and simple algebraic manipulations to obtain system-length distribution at arbitrary epoch using the system-length distribution at post-departure epoch. Some important performance measures, such as mean system lengths and mean waiting time have been obtained. Finally, some numerical results have been presented in the form of tables and graphs to show the applicability of the results obtained in this article. The model has potential application in areas of computer and communication networks, such as ethernet passive optical network (EPON).