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Internet users and Web-based applications continue to grow every day. The response time on a Web application really determines the convenience of its users. Caching Web content is one strategy that can be used to speed up response time. This strategy is divided into three main techniques, namely, Web caching, Web prefetching and application-level caching. The purpose of this paper is to put forward a literature review of caching strategy research that can be used in Web-based applications.

The methods used in this paper were as follows: determined the review method, conducted a review process, pros and cons analysis and explained conclusions. The review method is carried out by searching literature from leading journals and conferences. The first search process starts by determining keywords related to caching strategies. To limit the latest literature in accordance with current developments in website technology, search results are limited to the past 10 years, in English only and related to computer science only.

Note in advance that Web caching and Web prefetching are slightly overlapping techniques because they have the same goal of reducing latency on the user’s side. But actually, the two techniques are motivated by different basic mechanisms. Web caching uses the basic mechanism of cache replacement or the algorithm to change cache objects in memory when the cache capacity is full, whereas Web prefetching uses the basic mechanism of predicting cache objects that can be accessed in the future. This paper also contributes practical guidelines for choosing the appropriate caching strategy for Web-based applications.

This paper conducts a state-of-the art review of caching strategies that can be used in Web applications. Exclusively, this paper presents taxonomy, pros and cons of selected research and discusses data sets that are often used in caching strategy research. This paper also provides another contribution, namely, practical instructions for Web developers to decide the caching strategy.

Caching is commonly used to improve the performance of mobile computers. Due to the limitations of wireless networks (e.g. low bandwidth, intermittent connectivity), ensuring the consistency of cached data becomes a difficult issue. Existing research have shown that broadcast‐based cache invalidation techniques can effectively maintain cache consistency for mobile applications. However, most existing performance analysis of cache invalidation algorithms were carried out through simulation. Therefore, an analytical study is important to provide a deeper understanding of broadcast‐based invalidation techniques. In this paper, we present detailed analytical models of the major existing cache invalidation schemes. The models provide a basis to highlight the strengths and weaknesses of the different schemes and facilitate further investigation into cache invalidation for mobile environments. Extensive simulation has also been performed, and verifies the accuracy of the models developed.

XML is becoming one of the most important structures for data exchange on the web. Despite having many advantages, XML structure imposes several major obstacles to large document processing. Inconsistency between the linear nature of the current algorithms (e.g. for caching and prefetch) used in operating systems and databases, and the non‐linear structure of XML data makes XML processing more costly. In addition to verbosity (e.g. tag redundancy), interpreting (i.e. parsing) depthfirst (DF) structure of XML documents is a significant overhead to processing applications (e.g. query engines). Recent research on XML query processing has learned that sibling clustering can improve performance significantly. However, the existing clustering methods are not able to avoid parsing overhead as they are limited by larger document sizes. In this research, We have developed a better data organization for native XML databases, named sibling‐first (SF) format that improves query performance significantly. SF uses an embedded index for fast accessing to child nodes. It also compresses documents by eliminating extra information from the original DF format. The converted SF documents can be processed for XPath query purposes without being parsed. We have implemented the SF storage in virtual memory as well as a format on disk. Experimental results with real data have showed that significantly higher performance can be achieved when XPath queries are conducted on very large SF documents.

This paper investigates query processing in MANETs. Cache techniques and multi‐join database operations are studied. For data caching, a group‐caching strategy is proposed. Using the cache and the index of the cached data, queries can be processed at a single node or within the group containing this single node. For multi‐join, a cost evaluation model and a query plan generation algorithm are presented. Query cost is evaluated based on the parameters including the size of the transmitted data, the transmission distance and the query cost at each single node. According to the evaluations, the nodes on which the query should be executed and the join order are determined. Theoretical analysis and experiment results show that the proposed group‐caching based query processing and the cost based join strategy are efficient in MANETs. It is suitable for the mobility, the disconnection and the multi‐hop features of MANETs. The communication cost between nodes is reduced and the efficiency of the query is improved greatly.

This paper aims to discuss large‐scale operational aspects for network service maps and to present technical solutions and evaluation results.

The paper reviews related work on service discovery specifically for wireless networks and services in, introduces network service maps and their operation in detail and describes their implementation and addresses two specific usage scenarios, based upon which it evaluates its approach through measurements and simulations.

The paper finds that, in the presence of today's ever‐increasing WLAN services, better support for service selection and automated service configuration is an urgent need to enable people to access these new services efficiently and thus increase their value and utilisation further. This is clearly reflected in different solutions being developed by service providers, roaming operators and device manufacturers that aim to facilitate WLAN usage.

The ubiquity of WLAN services, ranging from campus networks to commercial hotspots and community WLAN services, requires a new approach for automatically locating and using services. The paper presents a service selection infrastructure that is independent of a user's current network attachment and location in a way that users can obtain information of a specific network (or any other service) without being required to be connected to a particular one. Information about networks and services are distributed in a way that allows for using this information offline, e.g. when still looking for appropriate network access.

The purpose of this paper is to evaluate how to use nodes in a cluster efficiently by studying the NAS Parallel Benchmarks (NASPB) on Intel Xeon and AMD Opteron dual CPU Linux clusters.

The performance results of the NASPB are presented both with one MPI process per node (1 ppn) and with two MPI processes per node (2 ppn). These benchmark results were analyzed by considering the impact of cache effects, code scalability, memory bandwidth within nodes, and the impact of MPI and the MPI communication network. Memory bandwidth was benchmarked using MPI versions of the Streams benchmarks. The impact of MPI and the MPI communication network are evaluated by benchmarking the performance of MPI sends and receives, MPI broadcast, and the MPI all‐to‐all routines.

The performance results from running the NASPB and from the memory bandwidth benchmarks show that better performance can sometimes be achieved using 1 ppn. Performance results show that the AMD Opteron/Myrinet cluster is able to achieve significantly better utilization of the second processor than the Intel Xeon/Myrinet cluster.

Most Linux clusters are purchased with two processors per node. One would like to run all applications on a cluster with two processors per node using 2 ppn instead of 1 ppn in order to utilize the second processor on each node. However, our results show that this is not always the best choice. Users should always assess their program performance with both 1 ppn and 2 ppn before running production calculations. This issue becomes even more important with the emergence of multi‐core processors.

To the authors' best knowledge, this is the only detailed comparison of AMD Opteron and Intel Xeon dual processor node parallel performance on large Myrinet clusters. The paper should be of value to everybody considering running on or purchasing AMD or Intel‐based Linux cluster.

Identification of topic changes within a user search session is a key issue in content analysis of search engine user queries. Recently, various studies have focused on new topic identification/session identification of search engine transaction logs, and several problems regarding the estimation of topic shifts and continuations were observed in these studies. This study aims to analyze the reasons for the problems that were encountered as a result of applying automatic new topic identification.

Measures, such as cleaning the data of common words and analyzing the errors of automatic new topic identification, are applied to eliminate the problems in estimating topic shifts and continuations.

The findings show that the resulting errors of automatic new topic identification have a pattern, and further research is required to improve the performance of automatic new topic identification.

Improving the performance of automatic new topic identification would be valuable to search engine designers, so that they can develop new clustering and query recommendation algorithms, as well as custom‐tailored graphical user interfaces for search engine users.

Traditionally, file transfer protocol (FTP) servers are major archive providers and users apply the Archie server to locate FTP archives. With the extreme popularity of the WWW, Web servers are now important archive providers and users download archives via HTTP. To reduce HTTP traffic, proxy cache servers are deployed on the Internet. However, we find the hit rate of archives in cache servers is quite low. This study proposes a combination of caching and better searching mechanisms to alleviate the problem. We enable a proxy server to automatically collect WWW and FTP archives from its cache, organize them in the form of an FTP directory, and then offer the directory list to the Archie. Accordingly, users can find archives on WWW and FTP servers through the Archie, and they can directly download archives from the proxy server, thus improving the reuse of cached archives. A system was implemented and operated in a real environment to evaluate the approach and results are discussed.

How can you call yourself a serious computer user if you don't have a 33MHz 486 system with a 16″ 1024×768 Super VGA screen and 300MB disk drive? Run right out and get the new goodies—otherwise, you're wasting your precious time. The above is an extreme position. On the other hand, if you're still using the equivalent of an IBM PC/XT (or, worse yet, an original PC), you're at the other extreme. Quite apart from the hype, you would almost certainly benefit from a more powerful PC. For most of us in the real world who are spending real dollars for equipment to serve real needs, the decisions can be tough: upgrade, replace, or let it be? And, if upgrading is the answer, what should you upgrade? This column deals with hardware questions. While there are few firm rules, there are some reasonable guidelines to consider. The author also provides notes from January‐June 1991 PC literature; it's been a great period for powermongers!