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61.
To evaluate Information Retrieval Systems on their effectiveness, evaluation programs such as TREC offer a rigorous methodology as well as benchmark collections. Whatever the evaluation collection used, effectiveness is generally considered globally, averaging the results over a set of information needs. As a result, the variability of system performance is hidden as the similarities and differences from one system to another are averaged. Moreover, the topics on which a given system succeeds or fails are left unknown. In this paper we propose an approach based on data analysis methods (correspondence analysis and clustering) to discover correlations between systems and to find trends in topic/system correlations. We show that it is possible to cluster topics and systems according to system performance on these topics, some system clusters being better on some topics. Finally, we propose a new method to consider complementary systems as based on their performances which can be applied for example in the case of repeated queries. We consider the system profile based on the similarity of the set of TREC topics on which systems achieve similar levels of performance. We show that this method is effective when using the TREC ad hoc collection.  相似文献   
62.
在达尔文出生的那个年代,没有人会接受关于进化和人类起源的自然主义学说,他在那个时代分享了他关于自然、上帝以及历史的观念。在“贝格尔号”航行之后,他提出的“生命始于同一祖先”理论如何能令人信服,是他面临的巨大挑战。自从达尔文开始进化论的研究之后,他对“我的理论”的推广并非一定意在反驳宗教教义,而是作为宗教和科学的进步。达尔文深信的一条教义,就是人类具有共同祖先或者说所有种族皆兄弟——这可作为废除黑奴制度的一个理论根据。英国已于1838年废除了奴隶制,世界的目光于是转向美国——该国奴隶制正如火如荼,并得到一种支持奴隶制、主张人种多元的新特创论的支持。达尔文的跨洋策略自19世纪50年代开始便深深影响着美国反奴隶制的精英博物学家,他们对共同祖先理论的支持将被用来颠覆这一人种多元特创论——比用《圣经》中那不足凭信的人种同一论更为有效。因此,他的理论可作为道德和科学领域的进步而引起美国基督教世界废奴主义者的兴趣。然而,该策略却从未完全发挥自身所有的潜力,这使特创论在20世纪萌生了新的形式。  相似文献   
63.
English Premiership Academy knee injuries: lessons from a 5 year study   总被引:1,自引:1,他引:0  
This study addresses the epidemiology of knee injuries in adolescent males. Data were collected prospectively from 41 Premiership soccer academies over a 5 year period from July 2000 to June 2005. A total of 12,306 player seasons were registered in the U9 to the U16 age categories with a total of 1750 recordable injuries specific to the knee joint. There was a mean incidence of 0.71 (95% confidence interval ± 0.05) knee injuries per player per year, and a median of 17 (inter-quartile range 9-38) training days and 2 (inter-quartile range 1-4) matches missed per knee injury. Knee injuries were found to be most common in the 14-16 year age group. Six hundred and nine (35% of total) injuries were classed as severe resulting in more than 28 days' absence. Injuries were more likely to be sustained in a competitive or match-play environment (862 or 52%) than in training (796 or 48%), and a non-contact mechanism was implicated in 823 (55%) of recorded cases. Peaks in injury numbers were seen in early season and subsequent to the winter break. Sprain was the most common diagnosis recorded, with the medial collateral ligament affected in 23% of all knee injuries. Knee injuries are common in elite youth footballers. In this uninsured age group, it could be argued that earlier medical intervention may reduce long-term damage to the immature skeleton.  相似文献   
64.
University counseling center clients’ (N = 52) perceptions of precounseling functioning were highly correlated with their actual well‐being scores at intake. The magnitude of change based on perceptions of precounseling functioning to current well‐being was approximately double of what is found from the difference of actual precounseling well‐being to current well‐being scores. Retrospective methods for assessing precounseling functioning are best suited for comparison among clients or counseling processes.  相似文献   
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The Internet has created new opportunities for librarians to develop information systems that are readily accessible at the point of care. This paper describes the multiyear process used to justify, fund, design, develop, promote, and evaluate a rehabilitation prototype of a point-of-care, team-based information system (PoinTIS) and train health care providers to use this prototype for their spinal cord injury and traumatic brain injury patient care and education activities. PoinTIS is a successful model for librarians in the twenty-first century to serve as publishers of information created or used by their parent organizations and to respond to the opportunities for information dissemination provided by recent technological advances.  相似文献   
68.
The typical nursery school in the province of Quebec, Canada, is conducted in French, the official language of schools and business. Even so, it is not unusual to find English- as well as French-speaking students at many of these schools. Both languages are spoken in the province.  相似文献   
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