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1.
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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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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Herbert C. Rudman 《Educational Measurement》1993,12(3):5-9
Are two national reports on standardized testing realistic or simplistic? What is the difference between “political” testing and conventional testing? What are some likely consequences of politicizing school testing? 相似文献
7.
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
8.
C. Addison Stone 《Learning disabilities research & practice》2002,17(3):201-203
The four articles on instructional discourse contributed by the members of the REACH project offer rich examples of the learning opportunities for students with learning disabilities (LD) in upper‐elementary and middle‐school content classrooms. In this commentary, I highlight possible reasons for variations in instructional engagement within and across the studies, discuss the challenges to engaging students with LD in discipline‐based instruction, and stress the value for the LD field of greater attention to instructional discourse. 相似文献
9.
H.C.K. Alewell 《Higher Education Quarterly》1990,44(2):123-141
Financing universities in times of increasing demands in all fields of public expenditure is a problem of nearly all European counnies not least because of the ongoing process of European integration. Comparing the different national systems of financing universities may be a means to foster cooperation and competition in a step by step growing network of universities in the European Community. This paper tries to give some insights into the German system; special considerotion is given to its federal structure and its implications for the universities' financthg system, because these problems may be of interest to other countries also. Of course this survey cannot be complete; details must be left to detailed information. The first part of the paper gives a survey of the higher education system in the Federal Republic of Gennany. The second part deals with the sources of funds, including the structure of mong streams to the universities. The third part refffs to the restrictions in using state money in the universities and the problems resulting; the fourth and final part concentrates on problems of the future, especially getring third party finds, and the diversifiation. of financing. 相似文献
10.
S Grant T Hasler C Davies T C Aitchison J Wilson A Whittaker 《Journal of sports sciences》2001,19(7):499-505
There is limited information on the anthropometry, strength, endurance and flexibility of female rock climbers. The aim of this study was to compare these characteristics in three groups of females: Group 1 comprised 10 elite climbers aged 31.3 +/- 5.0 years (mean +/- s) who had led to a standard of 'hard very severe'; Group 2 consisted of 10 recreational climbers aged 24.1 +/- 4.0 years who had led to a standard of 'severe'; and Group 3 comprised 10 physically active individuals aged 28.5 +/- 5.0 years who had not previously rock-climbed. The tests included finger strength (grip strength, finger strength measured on climbing-specific apparatus), flexibility, bent arm hang and pull-ups. Regression procedures (analysis of covariance) were used to examine the influence of body mass, leg length, height and age. For finger strength, the elite climbers recorded significantly higher values (P < 0.05) than the recreational climbers and non-climbers (four fingers, right hand: elite 321 +/- 18 N, recreational 251 +/- 14 N, non-climbers 256 +/- 15 N; four fingers, left hand: elite 307 +/- 14 N, recreational 248 +/- 12 N, non-climbers 243 +/- 11 N). For grip strength of the right hand, the elite climbers recorded significantly higher values than the recreational climbers only (elite 338 +/- 12 N, recreational 289 +/- 10 N, non-climbers 307 +/- 11 N). The results suggest that elite climbers have greater finger strength than recreational climbers and non-climbers. 相似文献