Two-queue polling systems with switching policy based on the queue that is not being served

We study a system of two non-identical and separate M/M/1/? queues with capacities (buffers) C₁ < ∞ and C₂ = ∞, respectively, served by a single server that alternates between the queues. The server’s switching policy is threshold-based, and, in contrast to other threshold models, is determined by the state of the queue that is not being served. That is, when neither queue is empty while the server attends Q_i (i = 1, 2), the server switches to the other queue as soon as the latter reaches its threshold. When a served queue becomes empty we consider two switching scenarios: (i) Work-Conserving, and (ii) Non-Work-Conserving. We analyze the two scenarios using Matrix Geometric methods and obtain explicitly the rate matrix R, where its entries are given in terms of the roots of the determinants of two underlying matrices. Numerical examples are presented and extreme cases are investigated.     

基于solaris平台的DNS服务器侦测和阻止DOS攻击的实现

DNS服务器所面临的威胁集中表现出了互连网的脆弱性,针对DNS服务器的拒绝服务攻击是DNS服务器面临的最大威胁.提出了一种针对查询攻击进行侦测和阻止的思路,并且在solaris的平台上用perl语言来实现,能够保证DNS服务器有效地抵御常规攻击,为正常用户提供及时的服务.同时,本文也对伪造源IP的分布式拒绝服务攻击提出了一种解决方案.     

网络游戏“私服”、“外挂”行为的民事法律责任研究

“私服”、“外挂”行为严重威胁和冲击着网络游戏产业的健康发展。界定了“私服”、“外挂’’行为，指出了“私服”、“外挂”行为的危害性．并在此基础上进一步研究了“私服”、“外挂”行为构成要件内容的特殊性、承担民事责任的方式和损害赔偿数额的确定，最后提出了“私服”、“外挂”的立法建议。这有利于网络游戏产业的健康发展，净化网络文化环境，打击“私服”、“外挂”行为。     

Polynomial Factorization for Servers with Semi-Markovian Workload: Performance and Numerical Aspects of a Verified Solution Technique

Abstract

We investigate polynomial factorization as a classical analysis method for servers with semi-Markov arrival and service processes. The modeling approach is directly applicable to queueing systems and servers in production lines and telecommunication networks, where the flexibility in adaptation to autocorrelated processes is essential.

Although the method offers a compact form of the solution with favourable computation time complexity enabling to consider large state spaces and system equations of high degree, numerical stability is not guaranteed for this approach. Therefore we apply interval arithmetic in order to get verified results for the workload distributions, or otherwise to indicate that the precision of the computation has to be improved. The paper gives an overview of numerical and performance aspects of factorization in comparison to alternative methods.     

SOCKS协议在防火墙中的应用研究

阐述了采用实现SOCKS协议的一种新型防火墙系统，较为详细地论述了其架构与功能，分析了SOCKS协议实现原理和过程。围绕SOCKS客户机与SOCKS服务器，给出了请求与响应格式及其建立连接实现功能的详细步骤，对比说明了SOCKS与Proxy的区别，突出了该系统的特点及其优越性。     

Non-linear models 1

This is the first application of a new method for testing stationary random point processes. Consider the class of all stationary ergodic point processes on the real line with arbitrary dependences among the inter–point distances (spacing).The hypothesis is :The observed process φ is a homogeneous Poisson process or more (resp.less) regular than a Poisson process.The sample is the vector of the first n points t₁, …,t_n.There is a close relation between our method for testing and queueing theory: For finding an appropriate test statistic, we observe the behaviour of a single server queue with the input φ.A table of critical values is given.     

共享存储型MIMD的几个问题

并行处理是提高计算机性能的有效手段,也是新一代计算机的结构特征,本文详细分析了共享存储型MIMD的几个问题,即:互连方式、cache一致性、可伸缩性等。     

无线视频服务器在ADSP-BF5614的研究与实现

通过对视频服务器相关资料的研究,提出了一种基于ADI公司专用DSP芯片ADSP-BF561的无线视频服务器的解决方案。硬件设计采用SAA7113芯片完成输入视频A/D转换,以ADSP-BF561芯片为核心硬件平台实现视频压缩编码,利用相应外围设备实现网络控制和传输。该方案由于使用了H.264视频编码标准、G729音频编码标准和基于CDMA1X无线网络技术的CDMA无线网络作为音视频数据的传输途径,具有良好的稳定性和可实现性。     

基于Web的企业管理CAI系统设计与开发

本文提出了一种基于Web的企业经营管理CAI系统,该系统尽可能真实地模拟了市场经济条件下实际企业竞争与经营管理的内、外部环境,为学习者提供了一个综合应用管理类知识的教育和实战环境。