一种基于DHT的Web缓存共享方法*

提出了一种基于DHT技术的Web缓存共享方法。该方法使得企业网络中所有节点能够相互共享浏览器中的本地缓存,从而形成一个高效的、大规模的分布式缓存共享系统。针对Web缓存共享的系统响应迅速的要求提出一种路由步长为O(2)的路由协议,保证Web查询请求最多只经过一次转发就可到达目标节点。性能分析和仿真实验的结果证明其在路由可靠性、命中率、系统响应和缓存代价方面均有满意的效果。     

决策支持系统中的分布式缓存机制

从如何提高DSS中查询的响应时间出发，提出了一种具有分布式缓存机制的决策支持系统，给出了系统的工作流程，并且介绍了系统中的缓存替换算法。实验表明这种系统的性能是良好的。     

气象OLAP系统数据显示的解决方案

基于B／S模式的系统架构中的图形信息的传递和缓存是实现分布式信息共享及显示的关键，采用MapXtreme for Java可以简化空间分析；将XML文件用于非结构化空间信息的存储与检索；使用servlet端的session技术缓存多用户使用的空间数据。这些技术气象数据挖掘处理系统的数据显示方案中，构成了基于浏览器的空间信息处理与显示的核心。     

数据网格中一种基于副本和缓存的元数据管理系统

元数据管理是数据网格的关键技术之一．对全局分布式存储系统GDSS(global distributed storage system)中的元数据管理进行了改进，提出了一种基于副本和缓存的分布式元数据管理系统RCMMS(replication and cache based distributed metadata management system)，缓存设置在GDSS系统中的存储服务点SSP(storage senice point)端．还讨论了RCMMS的设计、实现以及测试．RCMMS提供了动态管理元数据副本的有效算法．分析和测试表明，副本结合缓存的元数据管理方案在性能上超过了GDSS现有的元数据管理系统，有着较好的可靠性．     

分布式数据缓存技术研究

缓存技术在系统中的应用越来越广泛.主要对数据缓存进行研究,着重研究了分布式模式下的数据缓存技术.将数据缓存技术应用到社区平台的开发中,增加分布式解决方案.实验证明,分布式数据缓存技术能优化系统性能,提升数据访问效率.     

集中管理式Web缓存系统及性能分析

共享缓存文件是减少网络通信量和服务器负载的重要方法，本文在介绍Web Caching技术及流行的Web缓存通信协议ICP的基础上，提出了一种集中管理式Web缓存系统，该系统通过将用户的HTTP请求，按照一定的算法分发到系统中某一合适的缓存服务器上，从而消除了缓存系统内部服务器之间庞大的通信开销及缓存处理负担，减少了缓存内容的冗余度．通过分析，证明了集中管理式Web缓存系统比基于ICP的简单缓存系统具有缓存效率高、处理开销低、延迟小等优点，并且该系统具有良好的可扩展性．     

基于缓存的分布式统一身份认证优化机制研究

企业在进行应用系统集成时,普遍使用独立的身份认证系统来实现平台中身份信息的交换和共享。如何应对高并发、大用户流量的用户请求,是保障认证系统稳定、高效运行的重要问题。针对单认证中心负载过重,容易出现单点失效及系统响应慢的问题,提出了将认证服务器集群化的方案;将认证票据存储在缓存使得多个认证节点共享认证信息,并将重要且频繁使用的数据预存到缓存中以提高响应速度;结合复杂多样的用户行为提出了基于Hybrid的多因素缓存替换算法。实验结果表明,所采用的基于缓存的分布式认证架构能够保证系统的稳定性,提高系统的响应速度,改进的缓存替换算法提高了缓存命中率。     

GCaching--一种网格协同缓存系统

协同缓存通过多个代理缓存服务器的协同工作,可以充分利用各服务器的缓存空间,提高缓存命中率．网格技术可以方便地共享和整合异构的服务器资源．结合网格和协同技术,提出了一种网格协同缓存系统Gcaching,它将地域上分布的多个代理缓存服务器组成缓存池,充分利用缓存资源,协同工作,为用户提供更好的服务能力．Gcaching系统设计并实现了一种缓存放置和替换算法GCPR,它使用周期缓存更新策略,根据用户访问模式自适应地调整缓存数据的分布．仿真实验表明,GCPR算法的缓存命中率和平均访问跳数都优于传统的LRU等算法．     

云计算中一种分布式缓存加密存取方法

分布式缓存是云计算系统中提高应用程序性能的重要手段,针对云计算环境中分布式缓存的隐私问题,提出一种基于中国剩余定理的轻量级分布式缓存数据加密存取方法。该方法能够保护缓存数据的机密性,防止云计算环境中的其他用户、平台提供商或者攻击者获取明文缓存数据,且能够较好地保证缓存系统的性能,最后通过实验证明了该方法的有效性。     

基于J2EE平台集群服务的分布式缓存队列模型

集群缓存足提高J2FE(Java 2 Entcrprisc Edition)应用程序可扩展性能的关键技术，但目前J2EE提供的集群技术对于集群缓存的性能处理还存在一定的不足，该文在分析、12EE集群缓存技术的应用基础上，提出一种分布式缓存队列模型，可以有效地解决集群中的可靠性、可扩展性和失败转发等问题。实验表明，采用分布式缓存队列模型能提高集群的访问效率，是一种可行的解决方案。     

Latency-sensitive hashing for collaborative Web caching

Many geographically distributed proxies are increasingly used for collaborative Web caching to improve performance. In hashing-based collaborative Web caching, the response times can be negatively impacted for those URL requests hashed into geographically distant or overloaded proxies. In this paper, we present and evaluate a latency-sensitive hashing scheme for collaborative Web caching. It takes into account latency delays due to both geographical distances and dynamic load conditions. Each URL request is first hashed into an anchor hash bucket, with each bucket mapping to one of the proxies. Secondly, a number of nearby hash buckets are examined to select the proxy with the smallest latency delay to the browser. Trace-driven simulations are conducted to evaluate the performance of this new latency-sensitive hashing. The results show that (1) with the presence of load imbalance due to skew in request origination or hot-spot references, latency-sensitive hashing effectively balances the load by hashing into geographically distributed proxies for collaborative Web caching, and (2) when the overall system is lightly loaded, latency-sensitive hashing effectively reduces latency delays by directing requests to geographically closer proxies.     

一种有效的混合式P2P Web缓存系统HCache

针对当前P2P Web 缓存系统中副本过多的问题,提出了一种有效的混合式P2P Web缓存系统：HCache。HCache根据用户对网页的访问特点及网页的优先级,对网页进行有选择的缓存,进而减少P2P Web缓存系统中的副本个数。根据Web对象当前的流行度,对LRU替换策略进行了改进(ELRU),提高了P2P Web缓存的命中率。在日志驱动的模拟实验表明,HCache缓存系统提高了Web缓存的命中率和性能。     

Scalable Federation of Web Cache Servers

Web caches are traditionally organised in a simple tree like hierarchy. In this paper, a new architecture is proposed, where federations of caches are distributed globally, caching data partially. The advantages of the proposed system are that contention on global caches is reduced, while at the same time improving the scalability of the system since extra cache resources can be added on the fly. Among other topics discussed in this papers, is the scalability of the proposed system, the algorithms used to control the federation of Web caches and the approach used to identify the potential Web cache partners. In order to obtain a successful collaborative Web caching system, the formation of federations must be controlled by an algorithm that takes the dynamics of the Internet traffic into consideration. We use the history of Web cache access in order to determine how federations should be formed. Initial performance results of a simulation of a number of nodes are promising.     

Integrating Web Prefetching and Caching Using Prediction Models

Web caching and prefetching have been studied in the past separately. In this paper, we present an integrated architecture for Web object caching and prefetching. Our goal is to design a prefetching system that can work with an existing Web caching system in a seamless manner. In this integrated architecture, a certain amount of caching space is reserved for prefetching. To empower the prefetching engine, a Web-object prediction model is built by mining the frequent paths from past Web log data. We show that the integrated architecture improves the performance over Web caching alone, and present our analysis on the tradeoff between the reduced latency and the potential increase in network load.     

A locality aware cache diffusion system

Web caching is a widely deployed technique to reduce the load to web servers and to reduce the latency for web browsers. Peer-to-Peer (P2P) web caching has been a hot research topic in recent years as it can create scalable and robust designs for decentralized internet-scale applications. However, many P2P web caching systems suffer expensive overheads such as lookup and publish messages, and lack locality awareness. In this paper, we present the development of a locality aware cache diffusion system that makes use of routing table locality, aggregation, and soft state to overcome these limitations. The analysis and experiments show that our cache diffusion system reduces the amount of information processed by nodes, reduces the number of index messages sent by nodes, and improves the locality of cache pointers.     

A Scalable Web Server Architecture

This paper describes a scalable architecture for Web servers designed to cope with the ongoing increase of the Internet requirements. In the paper, first the drawbacks of the traditional Web server architecture are discussed, and the need for an innovative solution is described. The proposed design addresses two of the parameters that can dramatically impact the performance of Web servers: (1) the need for a powerful data management system to cope with the increase in the complexity of users' requests; and (2) an efficient caching mechanism to reduce the amount of redundant traffic. In this direction, a scalable solution based on distributed database technology to replace the file system is described, and performance test results of the system are provided. This architecture is further extended by a collaborative caching system that builds up an adaptive hierarchy of caches for Web servers, which allows them to keep up with the changes in the traffic generated by the applications they are running. Finally, some improvements to the proposed architecture are addressed.     

适应性Web缓存的研究

近年来,由于Web缓存技术对缓解因特网上热点现象的有效性,它已迅速得到了研究人员和业界的关注。适应性Web缓存(adaptive Web caching)由于能够根据用户的不同访问模式,自适应地调整热点数据在缓存系统中的分布,自动均衡整个缓存系统的负载,因而成为了缓存技术研究的一个新的热点。本文介绍了适应性Web缓存领域的研究状况,详细分析了基于组播和基于单播这两种主要的适应性缓存技术。最后,指出了适应性Web缓存研究存在的问题和值得进一步改进的方向。     

用自适应机制改进Web信息缓存管理的性能

目前,各种缓存（ｃａｃｈｉｎｇ）技术被广泛应用于Ｗｅｂ信息获取过程中,以求减少Ｉｎｔｅｒｎｅｔ的网络负载和提高响应速度,如何改进缓存技术从某种意义上成为制约Ｗｅｂ信息获取中的特点,然后提出了采用自适应机制改进Ｗｅｂ信息缓存管理性能的方法,同时给出了该方法的一些具体实现细节,该方法被应用于基于企业主题的Ｗｅｂ信息获取系统（ＷｅｂＣａｐｔｕｒｅ）的设计开发过程中,自适应机制的Ｗｅｂ信息缓存管理主要采用     

企业环境P2P模型下的合作式Web缓存系统研究

提出了一种高性能的合作式Web缓存系统(WebRing),包括一种基于连续哈希的Web对象路由模式,保证了对任意Web请求经过一次哈希计算且至多经过一次转发就可到达目标节点。同时,基于节点状态标记切割哈希空间的系统负载均衡算法大大提高了系统的吞吐量。解决了传统合作式缓存系统中多级转发和多重哈希计算造成的高时延和单点失效问题。     

Alternative Architectures and Protocols for Providing Strong Consistency in Dynamic Web Applications

Dynamic Web applications have gained a great deal of popularity. Improving the performance of these applications has recently attracted the attention of many researchers. One of the most important techniques proposed for this purpose is caching, which can be done at different locations and within different stages of the process of generating a dynamic Web page. Most of the caching schemes proposed in literature are lenient about the issue of consistency; they assume that users can tolerate receiving stale data. However, an important class of dynamic Web applications are those in which users always expect to get the freshest data available. Any caching scheme has to incur a significant overhead to be able to provide this level of consistency (i.e., strong consistency); the overhead may be so much that it neutralizes the benefits of caching. In this paper, three alternative architectures are investigated for dynamic Web applications that require strong consistency. A proxy caching scheme is designed and implemented, which performs caching at the level of database queries. This caching system is used in one of the alternative architectures. The performance experiments show that, despite the high overhead of providing strong consistency in database caching, this technique can improve the performance of dynamic Web applications, especially when there is a long network latency between clients and the (origin) server.