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Measuring Search Engine Quality 总被引:12,自引:3,他引:9
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. 相似文献
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Peter Davison 《Learned Publishing》2003,16(4):243-247
The Copyright Licensing and Administration Society of Singapore was established in 1999. It is now profitable and commercially significant, perhaps uniquely so in Asia. Critical factors in its growth have included a statutory (non‐voluntary) photocopying licence provision for educational institutions in the Copyright Act; and widespread support from the local and international communities of rightsholders. Tentative consensus has been established with educators over a fair level of remuneration for copying. Further work needs to be done to extend or amend the current model for electronic copying, for the private sector and for other countries in the region. 相似文献
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During the rewriting of its program in the early 1980s, theRassemblement pour la République (RPR) carried out anumber of opinion surveys. The person in charge of this wasnot a member of the inner leadership circle; he warned the partyleader, Jacques Chirac, that themes forming a coherent liberalprogram for the transformation of the relationship between citizens,state, and the economy, were not popular with public opinion,which remained attached to progressive taxation and a comprehensivesocial welfare system. The party leadership ignored these warnings.Rather than attempting to align their policies with voter aspirations,their principal use of political communications techniques aimedat improving their leader's image. The person in charge of thiswork was a stranger to politics whose understanding of the waycultural or political attitudes are changed led him to interpretvery fatalistically the chances of influencing election outcomesby communications techniques. His methods were treated withfrank skepticism by party communications colleagues, his client'spersonality was particularly unamenable to his efforts, andhis one successful initiativethe rejuvenation of theexecutive committeewas operated at the cost of a rowin the party. In the case of the RPR, opinion research seemsto have played no role at all in an important party policy review,the causes of which should be sought elsewhere. 相似文献
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First, I am pleased to note the broad area of agreement amongthe four of us. We concur fully that polls are useful, powerful,and play an important role in contemporary politics. My threeresponders also acknowledge the significance of alternativeways in which citizens can express their opinions and, furthermore,that public opinion is more diverse and nuanced than any dichotomoussplit between the pros and cons on a particular issue recordedat a particular time might suggest. Sir Robert chides me explicitly, and Gary Langer by implication,for failing 相似文献
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从加强学科建设谈高校图书馆数字化信息服务 总被引:9,自引:0,他引:9
从加强高校学科建设、培养和造就高水平学科带头人出发,分析高校图书馆数字化信息服务的现状,论述高校图书馆数字化信息服务的具体措施。 相似文献