基于LVS的高性能邮件防病毒系统的研究与实现

本文分析了高性能邮件系统防病毒的需求，在现有邮件防病毒技术的基础上着重研究了邮件防病毒的高性能技术，并提出了在邮件防病毒子系统中引入并发、负载平衡等高性能集群技术来解决防病毒系统与新型高性能邮件系统性能匹配问题的思想。在该思想指导下，实现了基于LVS的高性能邮件防病毒系统。     

Web邮件系统的设计和实现

ＷＥＢ邮件服务系统的原理、特点和它与非ＷＥＢ邮件服务的区别，并探讨了基于ＩＩＳ的ＷＥＢ邮件服务系统的设计和实现     

一种垃圾邮件过滤网关的设计

介绍了一种垃圾邮件过滤网关的设计方案，该系统应用于邮件服务器的前端，不依赖于所采用的邮件服务器系统。该系统按其功能可以划分为邮件采集模块、邮件过滤模块、数据库和邮件分析模块等四个部分。     

一种异构的Linux集群解决方案

简要介绍了集群的技术及其在Linux上的发展现状,分析了桌子新的集群实现技术,并且指出实用的集群系统的不足,提出一种强化了可管理性和数据一致性的异构Linux集群解决方案,以邮件集群系统为例进一步阐明异构集群系统的特性。     

最安全的邮件服务VisNetic MailServer

一套优秀的邮件服务系统，不仅是简单地提供收发邮件的功能，还应该具备高效的管理和安全方面的功能，如配置是否简单易行，SMTP路POP3连接服务是否快速高效、是否内置防火墙等，都是管理员在选择邮件服务系统时应考虑的问题！     

嵌入式系统下的邮件服务器的设计

目前Linux作为一种源码开放、安全可靠的系统平台，已成为嵌入式系统的首选操作系统。文中主要介绍嵌入式系统Linux下邮件收发系统的设计与开发。该邮件系统按照SMTP和POP3协议的规范，实现邮件系统的收发功能，包括邮件服务器和邮件客户端两部分。邮件服务器实现邮件的保存和传送功能。客户端可以执行邮件编辑、发送邮件和接收邮件等操作。该系统的设计坚持以方便用户为原则，它的逻辑清晰、界面简单友好，便于使用。     

基于校园网的I-office邮件服务的研究与实现

I-office系统是一个基于Internet的协同办公系统。邮件服务是I-office中的一个基础服务,它为用户和I-office中其它子系统提供邮件服务,包括收发邮件、通讯录维护等。通过独立的组织结构子系统实现联系人组的维护,通过I-office统一身份认证系统实现身份认证和身份漫游I。-office邮件服务支持任何遵循IMAP和SMTP协议的邮件服务器,并可以同用户个人办公系统中的邮件系统进行数据同步,协同工作。     

基于Mobile Agent的协作式反垃圾邮件系统设计

提出一种基于Mobile Agent技术的协作式反垃圾邮件体系结构，并对由代理服务器、反垃圾邮件客户端、动态负载均衡层、Mobile Agent层及反垃圾邮件服务器组成的五层结构进行阐述；代理服务器用来解决对邮件服务器的统一访问，降低由邮件服务器及客户端的多样性带来的系统复杂度；使用Nilsimsa算法实现相似邮件Hash过滤；最后对协作式反垃圾系统进行测试。     

Web邮件系统的设计和实现

电子邮件服务是一种重要的网络服务。本文介绍了ＷＥＢ邮件服务系统的原理、特点及其与非ＷＥＢ邮件服务的区别。并探讨了基于ＩＩＳ的ＷＥＢ邮件服务系统的设计和实现。     

反垃圾邮件网格系统的设计与实现

设计和实现了一种基于OGSA的反垃圾邮件网格系统，该系统解决了目前主流反垃圾邮件技术中存在的过于依赖服务器的缺点，通过网格对计算资源的强大整合和利用能力，为大量的反垃圾邮件计算服务。     

Dynamic configuration management in reliable distributed real-timeinformation systems

A new architecture for large-scale information systems is presented. The original aspects of the architecture are mainly: (1) the time-triggered, message-triggered object (TMO) structuring of the middleware and the application software of distributed real-time information systems; and (2) the dynamic configuration management subsystem (DCMS), based on the supervisor-based network surveillance (SNS) scheme. The positive impacts of this TMO structuring on maintainability and service interruption bounds are first discussed, with distributed replicated information service systems and other systems as examples. The main discussion is on the DCMS architecture. As a component of the DCMS, the network surveillance (NS) subsystem enables fast learning, by each interested fault-free node in the system, of the faults or repair completion events occurring in other parts of the system. Currently, concrete real-time NS schemes that are effective in distributed systems based on point-to-point network architectures are scarce. The SNS scheme presented in this paper is a semi-centralized real-time NS scheme which is effective in a variety of point-to-point networks. This scheme is highly scalable. An efficient implementation model for the SNS scheme is presented that can be easily adapted to various commercial operating system kernels. This paper also presents a formal analysis of the SNS scheme, on the basis of the implementation model, to obtain its strongly competitive tight bounds on the fault detection latency. Finally, some DCMS implementation issues are discussed that remain to be addressed in future research     

基于能量优化的无线传感器网络动态分簇目标跟踪

针对无线传感器网络动态分簇目标跟踪中的数据碰撞与簇首选择过程导致能耗过高问题,提出一种基于能量优化的无线传感器网络动态分簇方法。首先,构建时分竞选传输模型,主动避免动态簇内数据碰撞,降低节点能耗;然后,基于能量信息与跟踪质量,提出能量均衡的最远节点调度策略,优化簇头节点调度;最后,根据加权质心定位算法,完成目标跟踪任务。实验结果表明：在节点随机部署的环境下,所提方法对于非线性运动目标的平均跟踪精度为0.65 m,与多目标跟踪动态簇员选择方法（DCMS）相当,比分布式事件定位动态分簇目标跟踪算法（DELTA）提高了45.8%;能量消耗方面,与DCMS和DELTA相比,所提方法的动态跟踪簇能量消耗有效降低了61.1%,延长了网络寿命。     

Decentralized resource management for a distributed continuous media server

Distributed continuous media server (DCMS) architectures are proposed to minimize the communication-storage cost for those continuous media applications that serve a large number of geographically distributed clients. Typically, a DCMS is designed as a pure hierarchy (tree) of centralized continuous media servers. In an earlier work, we proposed a redundant hierarchical topology for DCMS networks, termed RedHi, which can potentially result in higher utilization and better reliability over pure hierarchy. We focus on the design of a resource management system for RedHi that can exploit the resources of its DCMS network to achieve these performance objectives. Our proposed resource management system is based on a fully decentralized approach to achieve optimal scalability and robustness. In general, the major drawback of a fully decentralized design is the increase in latency time and communication overhead to locate the requested object. However, as compared to the typically long duration and high resource/bandwidth requirements of continuous media objects, the extra latency and overhead of a decentralized resource management approach become negligible. Moreover, our resource management system collapses three management tasks: (1) object location, (2) path selection, and (3) resource reservation, into one fully decentralized object delivery mechanism, reducing the latency even further. In sum, decentralization of the resource management satisfies our scalability and robustness objectives, whereas collapsing the management tasks helps alleviate the latency and overhead constraints.     

数据中心能耗有效性系统框架构建

为降低数据中心的能量消耗,提出一个具有2层能耗模块结构的数据中心能耗有效性系统框架EADC,其中,虚拟环境管理子系统通过节点状态的按需变化降低能耗,数据中心管理子系统通过控制节点在应用间的按需切换满足其所有的服务需求。测试结果表明,ECDA可在满足能耗与性能要求的前提下实现能耗最低。     

Dr. Hadoop: an infinite scalable metadata management for Hadoop—How the baby elephant becomes immortal

In this Exa byte scale era, data increases at an exponential rate. This is in turn generating a massive amount of metadata in the file system. Hadoop is the most widely used framework to deal with big data. Due to this growth of huge amount of metadata, however, the efficiency of Hadoop is questioned numerous times by many researchers. Therefore, it is essential to create an efficient and scalable metadata management for Hadoop. Hash-based mapping and subtree partitioning are suitable in distributed metadata management schemes. Subtree partitioning does not uniformly distribute workload among the metadata servers, and metadata needs to be migrated to keep the load roughly balanced. Hash-based mapping suffers from a constraint on the locality of metadata, though it uniformly distributes the load among NameNodes, which are the metadata servers of Hadoop. In this paper, we present a circular metadata management mechanism named dynamic circular metadata splitting (DCMS). DCMS preserves metadata locality using consistent hashing and locality-preserving hashing, keeps replicated metadata for excellent reliability, and dynamically distributes metadata among the NameNodes to keep load balancing. NameNode is a centralized heart of the Hadoop. Keeping the directory tree of all files, failure of which causes the single point of failure (SPOF). DCMS removes Hadoop’s SPOF and provides an efficient and scalable metadata management. The new framework is named ‘Dr. Hadoop’ after the name of the authors.     

一种DCMS系统的设计与实现

介绍了基于POS,ATM机等DCMS(DeviceControlManagementSystem)的设备管理系统的设计过程,提出了一种针对现有业务管理的可扩展模型,使监控管理与设备完全分隔,从而既保障了现有设备日常的业务交易处理的正常运行,又增加了设备的动态管理,提高了设备的服务水平和利用效率,使该行业的管理上了一个新的台阶。     

Phoenix集群操作系统Web Portal的设计与实现

随着集群技术的普及，集群系统如何对外提供服务成为十分重要的课题。Phoenix是一体化、高可靠、高可扩展的集群操作系统。PWP（Phoenix Web Portal）位于Phoenix系统的最上层，旨在为各类用户访问Phoenix系统提供一站式的服务。该文介绍了PWP的设计与实现。     

‘First do no harm’: Factors influencing teachers’ ability and willingness to use ICT in their subject teaching

The paper reports on a Department of Culture, Museums and Sport (DCMS) funded project which provided modest amounts of time for teachers to be freed from their classroom teaching to explore the use of information and communications technology (ICT) in their subject teaching, and to meet up together to discuss their use of new technology. The funding was sufficient to provide a day of supply cover for two groups of secondary teachers in different curriculum subjects (history and science) to meet towards the start of the academic year to discuss their use of ICT, a day of supply cover to work on their ideas and interests, and a day to meet together again towards the end of the year to share ideas and experiences.     

Solving a group layout design model of a dynamic cellular manufacturing system with alternative process routings,lot splitting and flexible reconfiguration by simulated annealing

This paper presents a novel mixed-integer non-linear programming model for the layout design of a dynamic cellular manufacturing system (DCMS). In a dynamic environment, the product mix and part demands are varying during a multi-period planning horizon. As a result, the best cell configuration for one period may not be efficient for successive periods, and thus it necessitates reconfigurations. Three major and interrelated decisions are involved in the design of a CMS; namely cell formation (CF), group layout (GL) and group scheduling (GS). A novel aspect of this model is concurrently making the CF and GL decisions in a dynamic environment. The proposed model integrating the CF and GL decisions can be used by researchers and practitioners to design GL in practical and dynamic cell formation problems. Another compromising aspect of this model is the utilization of multi-rows layout to locate machines in the cells configured with flexible shapes. Such a DCMS model with an extensive coverage of important manufacturing features has not been proposed before and incorporates several design features including alternate process routings, operation sequence, processing time, production volume of parts, purchasing machine, duplicate machines, machine capacity, lot splitting, intra-cell layout, inter-cell layout, multi-rows layout of equal area facilities and flexible reconfiguration. The objective of the integrated model is to minimize the total costs of intra and inter-cell material handling, machine relocation, purchasing new machines, machine overhead and machine processing. Linearization procedures are used to transform the presented non-linear programming model into a linearized formulation. Two numerical examples taken from the literature are solved by the Lingo software using a branch-and-bound method to illustrate the performance of this model. An efficient simulated annealing (SA) algorithm with elaborately designed solution representation and neighborhood generation is extended to solve the proposed model because of its NP-hardness. It is then tested using several problems with different sizes and settings to verify the computational efficiency of the developed algorithm in comparison with the Lingo software. The obtained results show that the proposed SA is able to find the near-optimal solutions in computational time, approximately 100 times less than Lingo. Also, the computational results show that the proposed model to some extent overcomes common disadvantages in the existing dynamic cell formation models that have not yet considered layout problems.     

基于集群技术的Linux虚拟服务器

Linux虚拟服务器的目标是把很多实际服务器集中在一起组成一个可扩展和高可靠性的虚拟服务器。论文阐述了其工作原理,三种基于IP层负载平衡调度的方法和六种连接调度算法,并通过一个实例强调了Linux虚拟服务器的目的和设计。