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Tolga Yilmaz Rifat Ozcan Ismail Sengor Altingovde Özgür Ulusoy 《Information processing & management》2019,56(1):228-246
Students use general web search engines as their primary source of research while trying to find answers to school-related questions. Although search engines are highly relevant for the general population, they may return results that are out of educational context. Another rising trend; social community question answering websites are the second choice for students who try to get answers from other peers online. We attempt discovering possible improvements in educational search by leveraging both of these information sources. For this purpose, we first implement a classifier for educational questions. This classifier is built by an ensemble method that employs several regular learning algorithms and retrieval based approaches that utilize external resources. We also build a query expander to facilitate classification. We further improve the classification using search engine results and obtain 83.5% accuracy. Although our work is entirely based on the Turkish language, the features could easily be mapped to other languages as well. In order to find out whether search engine ranking can be improved in the education domain using the classification model, we collect and label a set of query results retrieved from a general web search engine. We propose five ad-hoc methods to improve search ranking based on the idea that the query-document category relation is an indicator of relevance. We evaluate these methods for overall performance, varying query length and based on factoid and non-factoid queries. We show that some of the methods significantly improve the rankings in the education domain. 相似文献
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Ismail Sengor Altingovde Özlem Nurcan Subakan Özgür Ulusoy 《Information processing & management》2013
In-memory nearest neighbor computation is a typical collaborative filtering approach for high recommendation accuracy. However, this approach is not scalable given the huge number of customers and items in typical commercial applications. Cluster-based collaborative filtering techniques can be a remedy for the efficiency problem, but they usually provide relatively lower accuracy figures, since they may become over-generalized and produce less-personalized recommendations. Our research explores an individualistic strategy which initially clusters the users and then exploits the members within clusters, but not just the cluster representatives, during the recommendation generation stage. We provide an efficient implementation of this strategy by adapting a specifically tailored cluster-skipping inverted index structure. Experimental results reveal that the individualistic strategy with the cluster-skipping index is a good compromise that yields high accuracy and reasonable scalability figures. 相似文献
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Mustafa Ulusoy 《Teaching in Higher Education》2016,21(5):532-544
This study aimed to evaluate the Pre-service Teachers’ (PSTs’) field experience-related perceptions and the qualities of their written reflections. Two thousand four hundred journal entries written by 75 teacher candidates were analyzed to classify their qualities. In addition, semi-structured interviews were conducted with all of the subjects. The results showed that the largest proportion of the written entries was classified as technical. Only a small percentage of the subjects reached the highest level of reflection called as transformative. During the field experiences, the PSTs had mainly self, cooperating teachers, and student-related issues and perceptions. At the end of the field experiences, they recommended to start the practicum courses from the first year of the faculty and to increase the weekly hours of these courses. It is important to note that the PSTs need additional knowledge and practices about the reflection, reflective writing, and the qualities of reflection. 相似文献
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International Journal of Science and Mathematics Education - This study presents a characterization of prospective early childhood teachers’ (ECEPTs) and prospective elementary school... 相似文献
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This paper explores the nature of prospective teachers’ noticing of students’ understanding as they analyze and discuss middle school students’ understandings of trapezoids in micro-case videos in the context of geometry. In this exploratory study, the data were obtained from eight prospective middle school mathematics teachers through individual video analysis, reflection papers, and group discussions. The results indicated that the use of purposeful micro-case video designs based on prospective teachers’ background knowledge of quadrilaterals allowed them to be productive in video analyses and discussions. In individual video analyses, prospective teachers attended to various mathematical elements to identify students’ responses but did not always use them to make interpretations of each student’s understanding of trapezoid. In the group discussions of the micro-case videos, in contrast, prospective teachers could provide alternative interpretations of students’ understanding by identifying links between the mathematical elements in students’ responses and the characteristics of students’ understandings. In the group discussions, they provided more detailed and specific instructional actions to support each student’s understanding of trapezoid than their individual video analyses. This study suggests practical implications for teacher education programs on how to use video cases (e.g., firstly, working individually and then having group discussions about the videos) to explore prospective teachers’ professional noticing skills. Considering prospective teachers’ background knowledge of related mathematical contents, this study can also inspire future studies on how to design effective videos about students’ mathematical understanding.
相似文献6.
The main purpose of this study was to determine pre-service teachers' use of reading strategies in their own readings. In addition, pre-service teachers' use of these strategies in their future teaching practices was also investigated. The subjects for this study were 505 pre-service teachers enrolled in one of the major universities in Ankara. The results of the study revealed that pre-service teachers employed 28 out of 38 reading strategies most of the time, but interview results illustrated that they reported using very limited scope of reading strategies. An interesting finding in this study was that all subjects accepted the responsibility to teach and improve their future students' reading skills. 相似文献
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Rifat Ozcan I. Sengor Altingovde B. Barla Cambazoglu Flavio P. Junqueira Özgür Ulusoy 《Information processing & management》2012
Caching is a crucial performance component of large-scale web search engines, as it greatly helps reducing average query response times and query processing workloads on backend search clusters. In this paper, we describe a multi-level static cache architecture that stores five different item types: query results, precomputed scores, posting lists, precomputed intersections of posting lists, and documents. Moreover, we propose a greedy heuristic to prioritize items for caching, based on gains computed by using items’ past access frequencies, estimated computational costs, and storage overheads. This heuristic takes into account the inter-dependency between individual items when making its caching decisions, i.e., after a particular item is cached, gains of all items that are affected by this decision are updated. Our simulations under realistic assumptions reveal that the proposed heuristic performs better than dividing the entire cache space among particular item types at fixed proportions. 相似文献
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Ka?an Huysal Yasemin U. Budak Ayse Ulusoy Karaca Murat Aydos Serdar Kahvecio?lu Mehtap Bulut Murat Polat 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(2):211-217
Introduction
Urinary tract infection (UTI) is one of the most common types of infection. Currently, diagnosis is primarily based on microbiologic culture, which is time- and labor-consuming. The aim of this study was to assess the diagnostic accuracy of urinalysis results from UriSed (77 Electronica, Budapest, Hungary), an automated microscopic image-based sediment analyzer, in predicting positive urine cultures.Materials and methods:
We examined a total of 384 urine specimens from hospitalized patients and outpatients attending our hospital on the same day for urinalysis, dipstick tests and semi-quantitative urine culture. The urinalysis results were compared with those of conventional semi-quantitative urine culture.Results:
Of 384 urinary specimens, 68 were positive for bacteriuria by culture, and were thus considered true positives. Comparison of these results with those obtained from the UriSed analyzer indicated that the analyzer had a specificity of 91.1%, a sensitivity of 47.0%, a positive predictive value (PPV) of 53.3% (95% confidence interval (CI) = 40.8–65.3), and a negative predictive value (NPV) of 88.8% (95% Cl = 85.0–91.8%). The accuracy was 83.3% when the urine leukocyte parameter was used, 76.8% when bacteriuria analysis of urinary sediment was used, and 85.1% when the bacteriuria and leukocyturia parameters were combined. The presence of nitrite was the best indicator of culture positivity (99.3% specificity) but had a negative likelihood ratio of 0.7, indicating that it was not a reliable clinical test.Conclusions:
Although the specificity of the UriSed analyzer was within acceptable limits, the sensitivity value was low. Thus, UriSed urinalysis results do not accurately predict the outcome of culture. 相似文献
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