Measuring Search Engine Quality

The effectiveness of twenty public search engines is evaluated using TREC-inspired methods and a set of 54 queries taken from real Web search logs. The World Wide Web is taken as the test collection and a combination of crawler and text retrieval system is evaluated. The engines are compared on a range of measures derivable from binary relevance judgments of the first seven live results returned. Statistical testing reveals a significant difference between engines and high intercorrelations between measures. Surprisingly, given the dynamic nature of the Web and the time elapsed, there is also a high correlation between results of this study and a previous study by Gordon and Pathak. For nearly all engines, there is a gradual decline in precision at increasing cutoff after some initial fluctuation. Performance of the engines as a group is found to be inferior to the group of participants in the TREC-8 Large Web task, although the best engines approach the median of those systems. Shortcomings of current Web search evaluation methodology are identified and recommendations are made for future improvements. In particular, the present study and its predecessors deal with queries which are assumed to derive from a need to find a selection of documents relevant to a topic. By contrast, real Web search reflects a range of other information need types which require different judging and different measures.     

利用三大检索查询收录/引用的方法与技巧

三大检索工具的各种版本在收录范围、检索性能上各不相同, 著者字段使用方法比较复杂。本文研究了各种版本的差异, 以及具体检索个人文章被收录、引用情况的方法与技巧, 最后介绍其它几种常用于科学评价的检索工具。     

中文搜索引擎检索语言研究

中文搜索引擎在很大程度上满了用户检索中文网络信息资源的要求，但也存在检索效果不够理想等问题，本文人检索语言的角度对现有中文搜索引擎进行分析，指出将检索语言的原理与方法应用于中文搜索引擎，必然极大地提高搜索引擎的检索效率。     

图书馆如何构筑自己的搜索引擎

主要由计算机和网络工作者设计开发的搜索引擎，经过一段时间的运行和实践，其弊端已越来越明显。专家们呼吁用“图书馆员的思维”来管理网上信息资源，这明网络信息的组织和管理呼唤以知识组织的理论来指导，才能达到高有序化。因此，图书馆应在网络信息时代抓住机遇，构筑自己的搜索引擎。     

专业搜索引擎在高校图书馆个性化信息服务中的应用

阐述了专业搜索引擎及其技术特点,针对高校图书馆个性化信息服务中科研和专业学科的特殊需要,运用专业搜索引擎的技术优势和特点,为用户提供专业学科信息资源的搜集,进一步增强高校图书馆个性化信息系统的服务能力.参考文献4.     

中外搜索引擎的比较研究

从信息产业发展角度对中外搜索引擎进行比较研究，剖析了中外搜索引擎的研制人员、商业运作机制等方面的差异，提出中文搜索引擎发展的建议。     

Analyzing imbalance among homogeneous index servers in a web search system

The performance of parallel query processing in a cluster of index servers is crucial for modern web search systems. In such a scenario, the response time basically depends on the execution time of the slowest server to generate a partial ranked answer. Previous approaches investigate performance issues in this context using simulation, analytical modeling, experimentation, or a combination of them. Nevertheless, these approaches simply assume balanced execution times among homogeneous servers (by uniformly distributing the document collection among them, for instance)—a scenario that we did not observe in our experimentation. On the contrary, we found that even with a balanced distribution of the document collection among index servers, correlations between the frequency of a term in the query log and the size of its corresponding inverted list lead to imbalances in query execution times at these same servers, because these correlations affect disk caching behavior. Further, the relative sizes of the main memory at each server (with regard to disk space usage) and the number of servers participating in the parallel query processing also affect imbalance of local query execution times. These are relevant findings that have not been reported before and that, we understand, are of interest to the research community.     

改进搜索引擎及其数据结构的设计

针对传统搜索引擎在搜索过程中产生的临时文件多、占用磁盘空间大的问题,本文改进了搜索引擎的数据结构,采用索引压缩技术减少了临时文件,提高了检索效率。     

基于模式识别理论的内燃机状态识别研究

用模式识别的理论和方法，对内燃机气门间隙的识别问题进行了探讨。在分析气门振动力学模型的基础上，通过测取振动信号获得故障特征信息，用模式识别的理论和方法，在建立状态特征模式空间的基础上实现对故障的分类识别。考虑到内燃机振动信号的复杂性，采用了外触发采样和有效截取的方法进行信号的数据采集和分析。     

WWW检索工具比较研究

近年来,随着ＷＷＷ技术的广泛应用,使得Ｉｎｔｅｒｎｅｔ迅速发展。作为Ｉｎｔｅｒｎｅｔ网上的信息查找途径,ＷＷＷ检索站点已成为Ｉｎｔｅｒｎｅｔ网上最繁忙的站点之一。本文选取了Ｙａｈｏｏ、ＡｌｔａＶｉｓｔａ、Ｅｘｃｉｔｅ、ＨｏｔＢｏｔ、Ｉｎｆｏｓｅｋ、Ｌｙｃｏｓ、ＯｐｅｎＴｅｘｔ、ＷｅｂＣｒａｗｌｅｒ及ＭｅｔａＣｒａｗｌｅｒ等九个著名的ＷＷＷ检索工具,通过上网实验,分析比较各工具检索引擎的特点,并从用户角度指出检索引擎现阶段存在的问题。最后对开发我国的ＷＷＷ检索工具提出了建议