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.     

论高校体育教学中学生创新思维能力的培养

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浅析足球运动员意志品质及培养方法

阐述了足球运动中意志品质的作用和地位、培养足球运动员意志品质的意义及各种方法.     

体育技术课教学中的测量与评价

体育技术的教学,是以身体素质为基础,运动能力和大脑思维为主导的复杂过程.应该遵循人体生长发育的规律,采取因势利导的原则,运用体育测量的科学性和体育评价的方法指导体育技术的教学.     

浅谈影响竞技体操裁判客观公正的若干因素及改进意见

文章分析论述了影响竞技体操裁判工作客观公正的若干因素及其改进意见.利用高科技手段,完善现代化的裁判系统,建立比赛规则模式系统是解决体操裁判工作客观公正的必由之路和最终目标.     

gn During Xinhai Revolution Ti

of Politics And Law,Beijing 102249,China; 2.the First Department of Law,Hebei Professional College of Politics And Law,Hebei Shijiazhang050091,Chian)Xinhai Revolution ended the feudal mo