加权的布尔型文本匹配算法研究     

吴柳燕 《柳州职业技术学院学报》2008,8(1):133-136

本文分析了传统的布尔型文本匹配算法的弊端和缺陷,结合图书文本信息的快速、高效的检索匹配要求,提出了加权的布尔型文本匹配算法。该算法对传统的文本匹配算法中漏检、误检和模糊查询等方面的问题进行了加权处理和结果校正,既保证查询算法的高效与全面性,同时又有效地控制了匹配的准确度,为图书信息查询系统的建立提供一种更好的解决方法。  相似文献   

The validity and reliability of a novel indoor player tracking system for use within wheelchair court sports     

James Rhodes  Barry Mason  Bertrand Perrat  Martin Smith 《Journal of sports sciences》2013,31(17):1639-1647

Abstract

The aim of the current study was to investigate the validity and reliability of a radio frequency-based system for accurately tracking athlete movement within wheelchair court sports. Four wheelchair-specific tests were devised to assess the system during (i) static measurements; (ii) incremental fixed speeds; (iii) peak speeds; and (iv) multidirectional movements. During each test, three sampling frequencies (4, 8 and 16 Hz) were compared to a criterion method for distance, mean and peak speeds. Absolute static error remained between 0.19 and 0.32 m across the session. Distance values (test (ii)) showed greatest relative error in 4 Hz tags (1.3%), with significantly lower errors seen in higher frequency tags (<1.0%). Relative peak speed errors of <2.0% (test (iii)) were revealed across all sampling frequencies in relation to the criterion (4.00 ± 0.09 m · sˉ¹). Results showed 8 and 16 Hz sampling frequencies displayed the closest-to-criterion values, whilst intra-tag reliability never exceeded 2.0% coefficient of variation (% CV) during peak speed detection. Minimal relative distance errors (<0.2%) were also seen across sampling frequencies (test (iv)). To conclude, the indoor tracking system is deemed an acceptable tool for tracking wheelchair court match play using a tag frequency of 8 or 16 Hz.  相似文献   

Competition and Instructional Set Effects On the Speed and Accuracy of a Throwing Task     

John B. Gross  Diane L. Gill 《Research quarterly for exercise and sport》2013,84(2):125-132

Abstract

Two experiments were conducted to investigate the effects of competition and instructional sets on the speed and accuracy of a dart-throwing task. In both experiments individuals competed against another subject on one day, and performed under noncompetitive conditions on a second day. The five distinct instructional sets varied from extreme emphasis on speed to extreme emphasis on accuracy. Multivariate analyses of variance revealed main effects for instructional sets on speed and accuracy in both experiments. Strong tradeoffs occurred with speed slowing and accuracy improving as the instructional emphasis changed from speed to accuracy. A competition by instructional sets interaction in Experiment 2 indicated that competition facilitated speed when speed was important, but when instructions emphasized accuracy, speed was slower in competition than in noncompetition. Accuracy was not affected by competition.  相似文献   

Theoretical Analysis of Aggressive Golf Putts     

J. F. Mahoney 《Research quarterly for exercise and sport》2013,84(2):165-171

Abstract

The present study examined the relationship between students' perceptions of the motivational climate and beliefs about the causes of success, preference for challenging tasks, and satisfaction in physical education. Responses of 50 female and 46 male students (M age = 12.08 years; SD = .72) showed that perceptions of a mastery-oriented motivational climate were related to the belief that motivation or effort caused success and satisfaction. In contrast, perceptions of a performance climate were related to the belief that deception caused success and related negatively to the students' preference for challenging tasks. Results of hierarchical regression analyses revealed that perceptions of the motivational climate explained a significant amount of unique variance in the students' responses after controlling for dispositional goal orientations. The results suggest that the teacher can influence the salience of a mastery-oriented climate and, in so doing, optimize a child's motivation in physical education.  相似文献   

Programming Time as a Function of Movement Constraint     

Andrew M. Gordon  Robert W. Christina 《Research quarterly for exercise and sport》2013,84(1):92-97

Abstract

Although the benefits of exercise are well documented, an international problem of physical inactivity exists. More research, especially theory based, has been recommended. One promising approach for studying exercise behavior is that proposed in the Transtheoretical Model (TTM) of behavior change. This model, however, has received minimal cross-cultural attention and, relative to the current study, measurement instruments have only recently been translated into the Finnish language. The purpose of this study was to assess American and Finnish college students' exercise behaviors on the basis of TTM. Participants were American (n = 169) and Finnish (n = 168) college students who completed language-specific measures of exercise behavior, stage of change, processes of change, decisional balance, self-efficacy, and temptation. The only cultural difference observed was that the American participants rated themselves higher on barrier self-efficacy relative to the Finnish participants. Regardless of nationality or gender, participants classified by their stage of change differed on all the core constructs assessed. These results generally support the utility of TTM for understanding American and Finnish college students' exercise behavior.  相似文献   

基于多层约束的叶轮数控进刀精度控制算法     

张云玲 《科技通报》2013,(9)

随着工业生产要求的不断增加,对叶轮的精度要求越来越高,这就给数控生产设备的控制精度提出了更高的要求,为了解决这一问题,提出一种基于多层约束的叶轮数控进刀精度控制算法,通过建立数控进刀控制模型,充分考虑进刀中叶轮的复杂情况。运用多层进刀条件约束模型方法,控制进刀精度,最大程度的满足精度要求,后期的计算机仿真实验证明,这种控制算法能够很好的完成叶轮数控进刀的多个约束条件的最优解计算,控制精度有了明显的提高。  相似文献   

搅拌站中液体外加剂精确计量系统设计     

商义叶  赵磊 《环球赛鸽科技》2013,(22)

高铁对混凝土配方中液体外加剂的用量有时较少,精度要求还很高,要求控制在±1%,且要求每一盘的精度均需达标。本文设计了一套精确的外加剂计量系统,该系统包括粗计量管路和精计量管路,在两套管路上增加电动阀门,通过单片机控制阀门的开关,并在精计量管路上增加球阀,可手动调节精计量的落差值,使外加剂的计量精度达到设定要求。  相似文献   

Accuracy of Estimates and Statistical Power for Testing Meditation in Latent Growth Curve Modeling     

JeeWon Cheong 《Structural equation modeling》2013,20(2):195-211

The latent growth curve modeling (LGCM) approach has been increasingly utilized to investigate longitudinal mediation. However, little is known about the accuracy of the estimates and statistical power when mediation is evaluated in the LGCM framework. A simulation study was conducted to address these issues under various conditions including sample size, effect size of mediated effect, number of measurement occasions, and R ₂ of measured variables. In general, the results showed that relatively large samples were needed to accurately estimate the mediated effects and to have adequate statistical power, when testing mediation in the LGCM framework. Guidelines for designing studies to examine longitudinal mediation and ways to improve the accuracy of the estimates and statistical power were discussed.  相似文献   

Extended essay marking on screen: is examiner marking accuracy influenced by marking mode?     

Martin Johnson  Rebecca Hopkin  Hannah Shiell  John F. Bell 《Educational Research and Evaluation》2013,19(2):107-124

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车载式施肥机肥量控制系统的性能探讨     

王兵利  朱瑞祥 《杨凌职业技术学院学报》2013,(1):11-14,20

通过对步进电机加螺旋装置、电液伺服系统、电动推杆、直流比例电磁铁和步进液压缸五种控制系统进行比较,电液伺服系统简便易行,控制精度高,响应速度快,使用寿命长,成本相对较低,适合在农业生产中推广应用。  相似文献