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Elke Achtert Christian B?hm Peer Kr?ger Peter Kunath Alexey Pryakhin Matthias Renz 《Informatik - Forschung und Entwicklung》2007,15(3):179-195
The reverse k-nearest neighbor (RkNN) problem, i.e. finding all objects in a data set the k-nearest
neighbors of which include a specified query object, has received increasing attention recently. Many
industrial and scientific applications call for solutions of the RkNN problem in arbitrary metric spaces
where the data objects are not Euclidean and only a metric distance function is given for specifying
object similarity. Usually, these applications need a solution for the generalized problem where the
value of k is not known in advance and may change from query to query. In addition, many applications
require a fast approximate answer of RkNN-queries. For these scenarios, it is important to generate
a fast answer with high recall. In this paper, we propose the first approach for efficient approximative
RkNN search in arbitrary metric spaces where the value of k is specified at query time. Our approach
uses the advantages of existing metric index structures but proposes to use an approximation of the
nearest-neighbor-distances in order to prune the search space. We show that our method scales significantly
better than existing non-approximative approaches while producing an approximation of the true query
result with a high recall. 相似文献
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Shmakova Anna Ryzhova Yulia Suhorukhih Alexey 《Education and Information Technologies》2022,27(2):2267-2282
Education and Information Technologies - The aim of the study is to develop an analytical framework to study the effect of Information and Communication Technology (ICT) education on humanistic... 相似文献
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Gender differences in mathematical performance have received considerable scrutiny in the fields of sociology, economics and psychology. We analyse a large data-set of high school graduates who took a standardised mathematical test in Russia in 2011 (n = 738,456) and find no substantial difference in mean test scores across boys and girls. However, boys have a greater variance of scores and are more numerous at the top of the distribution. We apply quantile regression to model the association between school characteristics and gender differences in test scores throughout the distribution of test scores. Male advantage in test scores, particularly at the top of the distribution, is concentrated in cities and in the schools with an advanced curriculum. In other high schools, especially in the countryside, gender differences in all parts of the distribution are small. We suggest several mechanisms based on selection and school effects that account for our findings. 相似文献
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Mikheev Alexey Serkina Yana Vasyaev Alexander 《Education and Information Technologies》2021,26(4):4537-4551
Education and Information Technologies - This research aimed to analyze the current trends in the digital transformation of educational institutions. The investigation lasted from November 2019 to... 相似文献
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Yi Liu Alexey Bessudnov Alison Black Brahm Norwich 《British Educational Research Journal》2020,46(3):532-552
In the past few decades, several countries have introduced reforms aimed at increasing school autonomy. We evaluate the effect of the introduction of autonomous academies in England on the educational trajectories of children with special educational needs. This has been done using longitudinal data on all schoolchildren in state schools in England, from the National Pupil Database. The results show that the effects of school autonomy on educational inclusion are not uniform and depend on schools’ previous performance and socio-economic composition. Schools that obtained autonomy under the control of an external sponsor (sponsored academies) were more likely to decrease the proportion of pupils with special needs and remove additional support for them. We do not observe these effects in the schools that voluntarily applied for the more autonomous status (converter academies). 相似文献
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Alexey Matyushkin 《High Ability Studies》1991,1(1):72-75
The intensive restructuring of Soviet society has led to the decision to establish the National Centre on Creative Giftedness to lead theoretical and applied research on the nature of giftedness both in children and adults. The development of a gifted person is viewed as an ideal model of normal development. The psychology of giftedness includes investigations into the nature of creativity and creative personality growth; the structure and dynamics of general ability and special capacities; the psychophysiology of individual differences; psychogenetic studies. Applied research involves educational practices based on creative problem discovery and problem solving. General giftedness is viewed as primarily expressing itself in problem sensitivity and sensitivity to nonstandard ways of solving them. It also involves a high ability to anticipate and forecast the future. The integral components of giftedness are considered in terms of an evaluation function based on the individual's perspective, intellectual and emotional ‘standards’. Special abilities are viewed as emerging against the framework of general giftedness. 相似文献
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本研究采用元分析方法,梳理分析近十年国内外学习共同体对学习效果影响的35项实验和准实验研究.结果表明:1)学习共同体对学习效果的整体平均效应值经调整后为0.352;2)学习共同体对认知及非认知学习效果均有中等程度的正向促进作用,其中对非认知层面的整体作用效果优于认知层面;3)学习共同体对学习效果的作用受调节变量的影响,学习模式、测量工具、测量方式对学习效果的调节作用组间差异显著;4)控制程度、共同体容量、教学周期、学段、课程类型、学习者类型对学习效果的调节作用组间差异不显著.最后,本研究结合元分析结果,为学习共同体的有效设计和实施提出建议. 相似文献
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在全球不断变暖的大环境下, 中国冻土区受气候影响而产生的各类结构性变化已经对人类生活产生相应的负面影响, 而位于俄罗斯西伯利亚地区的萨哈(雅库特)共和国面临同样的问题, 热喀斯特湖的发育对研究区内的领土开发、农耕地开垦、畜牧业等均已产生破坏性影响.借鉴俄罗斯对冻土的丰富研究, 为我国相关研究提供思路.通过梳理相关资料,... 相似文献
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