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11.
Lucijanic M Petrovecki M 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2012,22(2):151-155
Analyzing events over time is often complicated by incomplete, or censored, observations. Special non-parametric statistical methods were developed to overcome difficulties in summarizing and comparing censored data. Life-table (actuarial) method and Kaplan-Meier method are described with an explanation of survival curves. For the didactic purpose authors prepared a workbook based on most widely used Kaplan-Meier method. It should help the reader understand how Kaplan-Meier method is conceptualized and how it can be used to obtain statistics and survival curves needed to completely describe a sample of patients. Log-rank test and hazard ratio are also discussed. 相似文献
12.
Dragan Antić Bratislav Danković Saša Nikolić Marko Milojković Zoran Jovanović 《Journal of The Franklin Institute》2012,349(1):323-336
In this paper, we define a class of almost orthogonal rational functions of Legendre type in a new manner. Relations of these functions with classical exponentional functions orthogonal over interval (0, ∞), as well as classical polynomials orthogonal over (0, 1) are explained. Defining relations of these functions can be used for designing almost orthogonal filters. These filters are generators of orthogonal signals and can be successfully applied in finding the best signal approximation in the sense of the mean square error. The filters orthogonal property enables building of physical (in this case electrical) models of dynamical systems (the sources of signals to be approximated) either with less components for the same model accuracy or higher accuracy for the same number of components than the other known models. New filters represent further improvement of previously designed filters, by the same authors, in the sense of simplicity, higher accuracy, lesser approximation time and even a possibility to approximate signals generated by systems with built-in imperfections. Series of experiments were performed to analyze the dependence of approximation accuracy and the number of filters sections. 相似文献
13.
To reduce sensory uncertainty, humans combine cues from multiple senses. However, in everyday life, many co‐occurring cues are irrelevant to the task at hand. How do humans know which cues to ignore? And does this ability change with development? This study shows the ability to ignore cross‐modal irrelevant information develops late in childhood. Participants performed a sound discrimination task, with or without an irrelevant visual flash, presented synchronously in front of them. Adults ignored the irrelevant visual information, while 7‐ to 10‐year‐olds' responses were biased toward the flash location. The findings show that acquiring mature cue combination mechanisms is a multifaceted process that includes learning to ignore irrelevant cues, as well as to optimally combine relevant cues. 相似文献
14.
Hanna Dumont Kai Maaz Marko Neumann Michael Becker 《Zeitschrift für Erziehungswissenschaft》2014,17(2):141-165
Based on a theoretical model, which distinguishes between primary and secondary effects following Boudon, the present paper summarizes empirical evidence regarding the impact of family background on the transition from elementary into secondary school. In doing so, three types of secondary effects are distinguished: secondary effects of school grades, teacher recommendations, and the transition itself. The empirical literature suggests that both primary and secondary effects exist in the German school system: In addition to having lower achievement, children from disadvantaged backgrounds receive lower grades and fewer recommendations for higher tracks and are less likely to attend a high track even when controlling for their achievement. The paper closes by presenting findings from studies analyzing the relative importance of primary and secondary effects and a discussion on how effects of family background on the transition into secondary school can be reduced. 相似文献
15.
The article focuses on the question how competencies of students with different social backgrounds develop during elementary and secondary school. In particular, it addresses if achievement disparities which exist before school entrance increase, remain stable, or even diminish during schooling. The article draws on both national and international studies with longitudinal designs examining the achievement development of students of different social backgrounds during primary or secondary school. Although the results are mixed to some extent, a large part indicates that differences in achievement increase during the time of schooling. The evidence seems more consistent for achievement development during elementary school. Additionally, there is some indication that schools and features of the educational system contribute to increasing achievement disparities between students of different social backgrounds. 相似文献
16.
In a hierarchical XML structure, surrounding elements form the context of an XML element. In document-oriented XML, the context is a part of the semantics of the element and augments its textual information. The process of taking the context of the element into account in element scoring is called contextualization. This study extends the concept of contextualization and presents a classification of contextualization models. In an XML collection, elements are of different granularity, i.e. lower level elements are shorter and carry less textual information. Thus, it seems credible that contextualization interacts differently with diverse elements. Even if it is known that contextualization leads to improved effectiveness in element retrieval, the improvement on different granularity levels has not been investigated. This study explores the effect of contextualization on these levels. Further, a parameterized framework for testing contextualization is presented. 相似文献
17.
Josefine Lühe Michael Becker Marko Neumann Kai Maaz 《Zeitschrift für Erziehungswissenschaft》2017,20(3):499-519
Gender differences in educational outcomes are often reported. However, some evidence suggests that these differences are not consistent but vary with social background. In quantitative research, however, the interaction between gender and social background has been underinvestigated. The present study investigates whether the effect of gender on achievement is moderated by socio-economic status (SES). The sample consists of N = 3935 primary school-children in Berlin (6th grade). The results show that the effect of gender on achievement varies with SES, with a stronger correlation between the achievement of boys and their SES. Taken together, the results of the study suggest a differentiated consideration of the achievement of boys and girls and the importance of considering multiple group identities. 相似文献
18.
Marko Neumann Inge Schnyder Ulrich Trautwein Alois Niggli Oliver Lüdtke Rico Cathomas 《Zeitschrift für Erziehungswissenschaft》2007,10(3):399-420
Auf der Basis von zwei repr?sentativen Schülerstichproben der Schweizer Kantone Wallis (N = 926) und Fribourg (N = 778), die
w?hrend der 8. Jahrgangsstufe im Fach Franz?sisch als Fremdsprache unterrichtet wurden, geht der vorliegende Beitrag der Frage
nach, ob Schülerinnen und Schüler je nach besuchtem Bildungsgang unterschiedliche Fortschritte in der Entwicklung ihrer Fachleistungen
machen. Von besonderem Interesse ist dabei, ob und in welchem Ausma? die Zusammensetzung der Schülerschaft (Kompositions-effekte)
und m?glicherweise auch institutionell differierende didaktische und curriculare Angebote zwischen den Bildungsg?ngen (Institutionseffekte)
als lernmilieupr?gende Faktoren von Bedeutung für die Entwicklung der Fachleistungen sind. In Mehrebenenanalysen zeigten sich
auch nach Kontrolle der individuellen Eingangsvoraussetzungen (einschlie?lich des Vorwissens) bedeutsame Unterschiede in den
Lernzuw?chsen an den verschiedenen Bildungsg?ngen. Die weiteren Analysen lassen darauf schlie?en, dass sowohl von kompositionellen
als auch institutionellen Effekten auf die Leistungsentwicklung auszugehen ist. 相似文献
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20.
In 2011, the Finnish National Board of Education assessed the learning outcomes of history with a study whose results raised doubts about the fulfilment of the goals of history education. This article seeks to expand awareness about Finnish adolescents’ understanding of historical empathy. The study assessed twenty-two 16–17-year-old high school students’ ability to understand predecessors’ actions in particular historical situations. The study also examined how well a simulation exercise works as a tool of empathy teaching and evaluation. Students participated in the simulation and afterwards the students were interviewed. They also participated in a survey that measured their attitudes before and after the exercise, and wrote an essay at the end of the course. The results of the study show that most of the high school students did not reach the goals set for history teaching. The weak performance of students is explained by the strong tradition of history teaching which has been continuing in Finnish schools despite the curriculum reform. Teaching still concentrates on passing a meta-narrative on to students who have not yet enough experience of explaining historical events from a multiperspective point of view. 相似文献