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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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This study explored how members of competing host communities may endorse different acculturation orientations towards valued and devalued immigrants settled in the bilingual city of Montreal. Francophone (N=422) and Anglophone (N=401) host community students from low-, medium- and high-ethnic diversity colleges completed the host community acculturation scale (HCAS) along with a questionnaire monitoring a range of social psychological correlates of acculturation orientations. Results showed that Anglophones were more integrationist and individualist and less assimilationist than Francophones. Both Francophones and Anglophones were more integrationist and individualist and less assimilationist, segregationist and exclusionist toward valued than devalued immigrants. Attending a multiethnic college had no influence on respondents’ acculturation orientations. The more welcoming acculturation orientations of Anglophones compared to Francophones was corroborated by results obtained with immigrants attending the French and the English colleges. Social psychological profiles of the respective acculturation orientations were similar across both host communities thus supporting the construct validity of the HCAS. Attitude toward co-national outgroup was a significant determinant of each acculturation orientations, suggesting that intergroup relations between rival host communities has an impact on acculturation orientations toward immigrants. 相似文献
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V. J. Hinton D. C. De Vivo R. Fee E. Goldstein Y. Stern 《Learning disabilities research & practice》2004,19(3):146-154
Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disorder that presents with progressive muscular weakness. It is caused by a mutation in a gene that results in the absence of specific products that normally localize to muscle cells and the central nervous system (CNS). The majority of affected individuals have IQs within the normal range, generally with lower verbal than performance IQ scores. Prior work has demonstrated selective deficits on tests of verbal span and immediate memory. For the current study, 26 boys with DMD (and normal intellectual function) and their unaffected siblings were evaluated. Paired comparisons demonstrated that the children with DMD had significantly poorer academic achievement scores than their siblings, even though their vocabulary levels and home and educational environments were comparable. Children with DMD also had more behavioral concerns, physical disabilities, and poorer verbal memory spans. Linear regression indicated that behavioral concerns, executive function, and physical disability did not contribute substantially to academic performance, whereas performance on verbal span did. DMD presents with a selective developmental aberration in verbal span that has wide‐ranging consequences on learning skills. 相似文献
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Grace Y T Cheng 《Journal of the Medical Library Association》2004,92(4):445-458
OBJECTIVE: This article presents the results of complementary research studies on the behaviors of hospital clinicians in asking clinical questions and the relationship between asking of questions, outcome of information searches, and success in problem solving. METHODS: Triangulation in research methods--a combination of mailed questionnaires, interviews, and a randomized controlled study--was employed to provide complementary views of the research problems under study. RESULTS: The survey and interviews found that clinical problems (concerned mainly with therapy and equipment or technology) were expressed as statements rather than questions (average number of concepts = 1.7), that only slightly more than half (higher for doctors) of problems could be solved, and that the majority of clinical questions were not well formed. An educational workshop however improved clinicians' formulation of questions, but the use of structured prompting was found to improve building of hypotheses in the doctors' group without training. The workshop also improved satisfaction with the obtained information and success in problem solving. Nonetheless, for both the experimental and control groups, more structured and complete questions or statements did not mean higher success rates in problem solving or higher satisfaction with obtained information. CONCLUSION: The triangulation methods have gathered complementary evidence to reject the hypothesis that building well-structured clinical questions would mean higher satisfaction with obtained information and higher success in problem solving. 相似文献
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The purpose of this study was to assess receptivity to peer teaching and peer learning about the safe and appropriate use of medications among communitydwelling older adults. The sample was predominately White (88.5%), female (75.9%) older adults with an average age of 80.2 ( - 9.1) years. On average, the participants perceived their health status as good (2.8 - 0.6). In addition, participants reported using an average number of 4.4 ( - 3.3) prescribed medications. The majority (75%) of participants also reported no problems with their medications. With respect to receptivity to peer teaching and peer learning, the participants, on average, were neutral to peer teaching (6.0 - 2.4), but were somewhat receptive to peer learning (6.7 - 2.2). The number of prescribed medications that a participant reported taking and the age of a participant were identified as significant predictors of receptivity to peer teaching and accounted for 14.5% of the total variance ( F = 5.84, df = 2, p = 0.005). For receptivity to peer learning, the number of prescribed medications also was a significant predictor ( F = 7.50, df = 1, p = 0.008). This study provides the initial step to identifying community-dwelling older adults who would be receptive to peer teaching and peer learning about the safe and appropriate use of medications. 相似文献