排序方式： 共有16条查询结果，搜索用时 15 毫秒
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Olivier Chapelle Shihao Ji Ciya Liao Emre Velipasaoglu Larry Lai Su-Lin Wu 《Information Retrieval》2011,14(6):572-592
We study the problem of web search result diversification in the case where intent based relevance scores are available. A
diversified search result will hopefully satisfy the information need of user-L.s who may have different intents. In this
context, we first analyze the properties of an intent-based metric, ERR-IA, to measure relevance and diversity altogether.
We argue that this is a better metric than some previously proposed intent aware metrics and show that it has a better correlation
with abandonment rate. We then propose an algorithm to rerank web search results based on optimizing an objective function
corresponding to this metric and evaluate it on shopping related queries. 相似文献
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Popularity bias is an undesirable phenomenon associated with recommendation algorithms where popular items tend to be suggested over long-tail ones, even if the latter would be of reasonable interest for individuals. Such intrinsic tendencies of the recommenders may lead to producing ranked lists, in which items are not equally covered along the popularity tail. Although some recent studies aim to detect such biases of traditional algorithms and treat their effects on recommendations, the concept of popularity bias remains elusive for group recommender systems. Therefore, in this study, we focus on investigating popularity bias from the view of group recommender systems, which aggregate individual preferences to achieve recommendations for groups of users. We analyze various state-of-the-art aggregation techniques utilized in group recommender systems regarding their bias towards popular items. To counteract possible popularity issues in group recommendations, we adapt a traditional re-ranking approach that weighs items inversely proportional to their popularity within a group. Also, we propose a novel popularity bias mitigation procedure that re-ranks items by incorporating their popularity level and estimated group ratings in two distinct strategies. The first one aims to penalize popular items during the aggregation process highly and avoids bias better, while the second one puts more emphasis on group ratings than popularity and achieves a more balanced performance regarding conflicting goals of mitigating bias and boosting accuracy. Experiments performed on four real-world benchmark datasets demonstrate that both strategies are more efficient than the adapted approach, and empowering aggregation techniques with one of these strategies significantly decreases their bias towards popular items while maintaining reasonable ranking accuracy. 相似文献
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Homework is an important component of most physics courses. One of the functions it serves is to provide meaningful formative assessment in preparation for examinations. However, correlations between homework and examination scores tend to be low, likely due to unproductive student behavior such as copying and random guessing of answers. In this study, we attempt to model these two counterproductive learner behaviors within the framework of Item Response Theory in order to provide an ability measurement that strongly correlates with examination scores. We find that introducing additional item parameters leads to worse predictions of examination grades, while introducing additional learner traits is a more promising approach. 相似文献
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Emre Özçelik 《Research Policy》2004,33(3):409-424
We examine the determinants of export performance of firms in the Turkish manufacturing industry. Prominent differences show up between innovator and non-innovator firms in terms of the impacts of such variables as firm size, advertisement intensities, ownership structures, and composition of employees. Importance of innovations and R&D activities, conduciveness of capital intensity, and insignificance of the real wage are meaningful as far as a rational international competition policy is concerned. Results are suggestive of a technology-oriented and capital-formative development path, if Turkey is to come up with the international competitive standards. 相似文献
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Judith Lederman Norman Lederman Selina Bartels Juan Jimenez Mark Akubo Shereen Aly Chengcheng Bao Estelle Blanquet Ron Blonder Mariana Bologna Soares de Andrade Catherine Buntting Mustafa Cakir Heba EL-Deghaidy Ahmed ElZorkani Estelle Gaigher Shuchen Guo Arvi Hakanen Soraya Hamed Al-Lal Cigdem Han-Tosunoglu Annemarie Hattingh Anne Hume Serhat Irez Gillian Kay Ozgur Kivilcan Dogan Kerstin Kremer Pi-Chu Kuo Jari Lavonen Shu-Fen Lin Cheng Liu Enshan Liu Shiang-Yao Liu Bin Lv Rachel Mamlok-Naaman Christine McDonald Irene Neumann Yaozhen Pan Eric Picholle Ana Rivero García Carl-Johan Rundgren David Santibáñez-Gómez Kathy Saunders Renee Schwartz Frauke Voitle Jakob von Gyllenpalm Fangbing Wei Jocelyn Wishart Zhifeng Wu Huang Xiao Yalcin Yalaki Qiaoxue Zhou 《科学教学研究杂志》2019,56(4):486-515
Although understandings of scientific inquiry (as opposed to conducting inquiry) are included in science education reform documents around the world, little is known about what students have learned about inquiry during their elementary school years. This is partially due to the lack of any assessment instrument to measure understandings about scientific inquiry. However, a valid and reliable assessment has recently been developed and published, Views About Scientific Inquiry (VASI; Lederman et al. [2014], Journal of Research in Science Teaching, 51, 65–83). The purpose of this large-scale international project was to collect the first baseline data on what beginning middle school students have learned about scientific inquiry during their elementary school years. Eighteen countries/regions spanning six continents including 2,634 students participated in the study. The participating countries/regions were: Australia, Brazil, Chile, Egypt, England, Finland, France, Germany, Israel, Mainland China, New Zealand, Nigeria, South Africa, Spain, Sweden, Taiwan, Turkey, and the United States. In many countries, science is not formally taught until middle school, which is the rationale for choosing seventh grade students for this investigation. This baseline data will simultaneously provide information on what, if anything, students learn about inquiry in elementary school, as well as their beginning knowledge as they enter secondary school. It is important to note that collecting data from all of the approximately 200 countries globally was not humanly possible, and it was also not possible to collect data from every region of each country. The results overwhelmingly show that students around the world at the beginning of grade seven have very little understandings about scientific inquiry. Some countries do show reasonable understandings in certain aspects but the overall picture of understandings of scientific inquiry is not what is hoped for after completing 6 years of elementary education in any country. 相似文献
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The UK's Research Excellence Framework (REF) is a system that is intended to evaluate the quality of the research produced by higher education institutes (HEIs) in the UK in three areas: quality of research outputs; impact of this research beyond academia; and research environment. For the next REF, the funding bodies have reviewed the importance of the three assessment elements and decided to increase the weight of ‘impact’ to 25% (from 20% in REF2014) and decrease the weight of ‘outputs’ to 60% (from 65% in REF2014). This article first examines the relevance of some factors for the quality of impact submissions in REF2014 and finds that larger submissions and institutes with higher external research income received better impact scores in the REF. The article then examines the units of assessment (UoAs) and HEIs that benefitted from the inclusion of the impact agenda as part of REF2014 by examining the distribution of the quality-related research (QR) funding in the 2017–2018 period and finds that the QR funding gap among different UoAs tends to decrease but the gap among HEIs in most of the UoAs increased. With the increased importance of the impact agenda as a criterion for funding bodies, it is expected that research income will be concentrated in fewer universities in the future, with the increased importance of non-academic impact. This article also discusses some of the gaming strategies and long-term investment priorities that HEIs may engage in based on the new submission rules of the next REF. 相似文献
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The present study aims to identify first year Turkish Science undergraduates’ understandings and misconceptions of the concept
of light and its propagation. For this purpose, an instrument composed of four open-ended questions was developed by the researchers.
The diagnostic test was piloted with twenty students and modifications were made prior to the final administration of the
test. The content validity of the test questions was assessed by two physics researchers and one lecturer. These questions
were administered to a hundred first year undergraduates (aged 16–18) enrolled in the Science Teacher Training Department
in Ataturk University in Turkey. In addition, the semi-structured interviews of 30–40 min were conducted with the four students
whose responses involved common misunderstanding. All interview records were transcribed and analysed. The findings showed
that undergraduates’ understanding of light is poor and also they have important and prevalent misconceptions. Identified
misconceptions, some of which have been reported in the literature, are discussed qualitatively. The misunderstandings identified
were compared with those in the literature. The results have some implications for teaching light, suggesting that a substantial
revision of teaching strategies is needed.
相似文献
| Mehmet YalcinEmail: |
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Since Proportional?+?Integral?+?Derivative (PID) controller is still the workhorse in taking over the workload of process control systems, this article introduces a new design methodology toward improving the performance of such controller. After a PI control law with windup protection is given, it is combined with a derivative path employing a first-order low pass filter in an innovative way to develop a performant controller called PI?+?DF controller. In attempting to attain a high level of control performance, gains of this controller including proportional, integral, derivative and filter gains are tuned choosing the recently introduced Stochastic Fractal Search (SFS) algorithm owing to its superiority to many state-of-the-art algorithms considering convergence, accuracy and robustness. To evaluate the efficacy of SFS, Particle Swarm Optimization (PSO) is also applied to the case study. Furthermore, the presented SFS optimized PI?+?DF controller is compared to a recently reported control scheme through simulation and experimental tests on an identical DC servo system. After providing the stability proof, SFS tuned PI?+?DF controller is found to be the pioneer in exhibiting the most accurate speed response profile under complicated scenarios, which is followed by PSO tuned PI?+?DF controller and the existing control approach, respectively. 相似文献