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The need to cluster small text corpora composed of a few hundreds of short texts rises in various applications; e.g., clustering top-retrieved documents based on their snippets. This clustering task is challenging due to the vocabulary mismatch between short texts and the insufficient corpus-based statistics (e.g., term co-occurrence statistics) due to the corpus size. We address this clustering challenge using a framework that utilizes a set of external knowledge resources that provide information about term relations. Specifically, we use information induced from the resources to estimate similarity between terms and produce term clusters. We also utilize the resources to expand the vocabulary used in the given corpus and thus enhance term clustering. We then project the texts in the corpus onto the term clusters to cluster the texts. We evaluate various instantiations of the proposed framework by varying the term clustering method used, the approach of projecting the texts onto the term clusters, and the way of applying external knowledge resources. Extensive empirical evaluation demonstrates the merits of our approach with respect to applying clustering algorithms directly on the text corpus, and using state-of-the-art co-clustering and topic modeling methods. 相似文献
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Yuan-feng DUAN Ru ZHANG Yang ZHAO Siu-wing OR Ke-qing FAN Zhi-feng TANG 《浙江大学学报(A卷英文版)》2011,12(12):895-901
Steel structures are widely used in railway infrastructures. Their stress state is the most important determinant of the safety
of these structures. The elasto-magnetic (EM) sensor is the most promising for stress monitoring of in-service steel structures.
Nevertheless, the necessity of magnetic excitation to saturation due to the use of a secondary coil for signal detection,
keeps from its engineering application. In this paper, a smart elasto-magneto-electric (EME) sensor using magneto-electric
(ME) sensing units to take the place of the secondary coil has been exploited for the first time. The ME sensing unit is made
of ME laminated composites, which has an ultrahigh ME voltage coefficient and can measure the magnetic induction simply and
precisely. Theoretical analysis and characterization experiments firstly conducted on the ME laminated composites showed that
the ME sensing units can be applied in the EM sensor for improved performance in stress monitoring. A tension test of a steel
bar was carried out to characterize our smart EME sensor and the results showed high accuracy and sensitivity. The present
smart EME sensor is a promising tool for stress monitoring of steel structures in railway and other civil infrastructures. 相似文献
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Situated Simulation-Based Learning Environment to Improve Proportional Reasoning in Nursing Students
Ilana Dubovi Sharona T. Levy Efrat Dagan 《International Journal of Science and Mathematics Education》2018,16(8):1521-1539
Proportional reasoning is the basis for most medication calculation processes and is fundamental for high-quality care and patient safety. We designed a simulated Medication Mathematics (siMMath) environment to support proportional reasoning in transitioning via concreteness fading between two mediators. The first mediator is simulated nursing tools of medication preparation. The second is a ratio-table setup which is used as a goal representation, which enables one to spatially hold in place different quantities in their relative proportion. We conducted a two-part study with nursing students. Part 1 was a quasi-experimental pretest–intervention–posttest design assessing the effectiveness of learning, by evaluating four categories of medical calculation questionnaire items (solid medications, unit conversion, concentrations, infusion rates). We used the Noelting proportional reasoning test to evaluate the generalizability and abstraction of proportional reasoning. Part 1 included an experimental group (n = 96) learning with siMMath, and a comparison group (n = 73) learning with an equation-based lecture approach. Part 2 employed a case study design to characterize the learning process. The experimental group’s learning gains were significantly higher than the comparison group’s for the two most challenging categories of the medication calculation problems questionnaire, namely concentrations and infusion rates. Furthermore, the experimental group’s learning gains were significantly higher than the comparison group’s for formal operational reasoning on the Noelting test. Students who used a ratio-table setup scored significantly higher on the Noelting posttest questionnaire. Nursing students who learned with the siMMath environment overcame difficulties in proportional reasoning to the highest levels and extended this understanding to other contexts. 相似文献
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The primary purpose of this exploratory field study was to examine the use of cognitive behavioural strategies by highly skilled orienteers prior to and during competition. A secondary purpose of the study was to investigate whether differences in the level of qualification in orienteering is related to state anxiety. The subjects were divided into three classes with respect to their international and national records. The first two classes (A and B) were composed of international and national level athletes. The third class (C) included orienteers with unknown international records. Examination of the use of behavioural cognitive strategies during competition indicated that all orienteers reported a moderate use of mental imagery, above moderate use of inner talk and a focus of attention on present action rather than past or future. The other major findings were that prior to competition, superior orienteers reported use of higher self‐efficacy, more positive outcome expectations and more task demand orientation than their less successful counterparts. Top orienteers coped more successfully with pre‐competition anxiety by lowering their anxiety to a more moderate level prior to the actual performance. 相似文献
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Alejandro?BellogínEmail authorView author&#;s OrcID profile Pablo?Castells Iván?Cantador 《Information Retrieval》2017,20(6):606-634
There is an increasing consensus in the Recommender Systems community that the dominant error-based evaluation metrics are insufficient, and mostly inadequate, to properly assess the practical effectiveness of recommendations. Seeking to evaluate recommendation rankings—which largely determine the effective accuracy in matching user needs—rather than predicted rating values, Information Retrieval metrics have started to be applied for the evaluation of recommender systems. In this paper we analyse the main issues and potential divergences in the application of Information Retrieval methodologies to recommender system evaluation, and provide a systematic characterisation of experimental design alternatives for this adaptation. We lay out an experimental configuration framework upon which we identify and analyse specific statistical biases arising in the adaptation of Information Retrieval metrics to recommendation tasks, namely sparsity and popularity biases. These biases considerably distort the empirical measurements, hindering the interpretation and comparison of results across experiments. We develop a formal characterisation and analysis of the biases upon which we analyse their causes and main factors, as well as their impact on evaluation metrics under different experimental configurations, illustrating the theoretical findings with empirical evidence. We propose two experimental design approaches that effectively neutralise such biases to a large extent. We report experiments validating our proposed experimental variants, and comparing them to alternative approaches and metrics that have been defined in the literature with similar or related purposes. 相似文献
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Shwartz Gabriella Shav-Artza Or Dori Yehudit Judy 《Journal of Science Education and Technology》2021,30(5):692-705
Journal of Science Education and Technology - In response to the realization that qualified applicants’ choice of a career in chemistry is declining, we investigated the factors involved in... 相似文献
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Stein D Pat-Horenczyk R Blank S Dagan Y Barak Y Gumpel TP 《Journal of learning disabilities》2002,35(3):268-275
We evaluated 32 nonmedicated male adolescents diagnosed with attention-deficit/hyperactivity disorder (ADHD) in childhood, 35 male adolescents similarly diagnosed who were receiving methylphenidate (MPH), and 77 control boys. Both ADHD groups completed self-report questionnaires assessing sleep disturbances; weekday and holiday sleep duration; and symptoms of ADHD, anxiety, and depression. Parents and teachers rated the severity of the participants' ADHD. The control group completed self-report questionnaires assessing sleep disturbances. We found that nonmedicated participants and controls did not differ in the severity of sleep disturbance. In contrast, the medicated participants demonstrated a significantly greater severity of sleep disturbance compared with the nonmedicated participants and reported elevated levels of symptoms of ADHD, anxiety, and depression. Specific analyses showed that depressive symptoms contributed significantly to the degree of sleep disturbance when controlling for ADHD diagnosis and MPH treatment. These findings suggest that among adolescents with ADHD symptoms, the severity of symptoms of depression may contribute to the degree of sleep disturbance in addition to the effect of their primary disorder and MPH treatment. 相似文献
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Listening plays a crucial part in the learning of overseas students in the United Kingdom. Students can never follow a lecture or discussion in English without listening. Traditional classroom teaching in listening limits students＇ time and space. However, the Web-based listening course accommodates listeners a great deal, enabling them to access the Internet at their own pace. In this paper, the author would like to study on a language learning Website for developing learners＇ listening skills, designed by the CELE （Centre for English Language Education） at the University of Nottingham. In the first part, the author will review the issues concerning listening, conventional materials design, CALL （computer assisted language learning） and actual Websites established for EAP （English academic purposes）. Through analysis, the author would develop a set of evaluation criteria in order to evaluate the CELE listening Website. These guidelines should also be helpful for teachers and students to select suitable online listening materials. By using these criteria and comparing with other Websites for similar purposes, the author would highlight the strengths and weaknesses of the CELE Website and offer suggestions for its improvement. In the last section, the author would consider the generalisability of the Website in respect of design principles, exercise types and tools, to check whether it is appropriate for teaching listening in a specific context and whether it is applicable for creating a parallel site developing reading skills. 相似文献