Robuste Indizes für Projection Pursuit     

Tobias Rohatsch  Gerhard P?ppel  Heinrich Werner 《Informatik - Forschung und Entwicklung》2002,4(1):53-59

Die moderne und hoch komplexe Fertigung, z.B. in der Halbleiterindustrie, erfordert für die dabei anfallenden Messdaten der Anlagen- bzw. Prozessparameter multivariate Analysemethoden. Eine dieser m?glichen Analysemethoden ist Projection Pursuit (PP). Dieses Verfahren ist durch geschickte Wahl des so genannten Projektionsindex in der Lage, verschiedenste Datencharakteristika zu detektieren und diese auf anschauliche Weise zu visualisieren. Bei den Projektionsindizes handelt es sich um Funktionen, die eine Projektion auf unterschiedliche Merkmale hin bewerten und dabei jeder Projektion einen Funktionswert zuweisen. Dieser Funktionswert spiegelt die Aussagekraft der Projektion (in Abh?ngigkeit vom verwendeten Index) wider. Die Auswahl bzw. der Aufbau dieser Indizes ist hierbei von entscheidender Bedeutung. Alle hier vorgestellten Indizes zeichnen sich vor allem durch ihren robusten Charakter gegenüber durch Ausrei?er kontaminierte Daten, wie sie in realen Datenszenarien vorkommen, aus. Die durch Anwendung dieser Indizes gewonnenen Einblicke in die komplexe Struktur der Daten erm?glichen es, hochdimensionale Parameterabweichungen und komplexe Zusammenh?nge innerhalb der Daten zu finden.  相似文献   

Die Bedeutung von Handlungskonzepten für die Interpretation sportpädagogischer Prozesse     

Gerhard Kaminski 《Sportwissenschaft》1979,9(1):9-28

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Vocational Education and Training: Researching the Relationship between School and Work     

Regina H. Mulder  Gerhard Messmann  Christoph König 《European Journal of Education》2015,50(4):497-512

Researchers and policy makers agree that the relation between school and work is an important characteristic of vocational education and training (VET) and needs attention. The relation itself poses several challenges for research to be successful and useful for policy makers. In this article, we outline these challenges and answer the following question: What needs to be considered when researching the relation between school and work? Our central claim is that research on the relation between school and work needs to (1) take into account contextual conditions of the VET system, including identifying the central actors and their responsibilities within a VET system, (2) take into account the characteristics of VET itself, (3) define the quality of the relation between school and work (depending on the context, characteristics of the VET system and VET itself), and (4) be consistent with respect to chosen research aims and paradigms. To illustrate how these aspects can be taken into account an example of empirical research conducted in the German dual apprenticeship system is described. The readers are provided with guidelines for researchers and policy makers to carry out high quality research on the relation between school and work in VET systems that enables policy makers to make use of the results to improve the relation between school and work in VET systems.  相似文献   

Bookreviews     

Brian Holmes  G. L. de Landsheere  E. Eaglesham  J. Idenburg  H. S. McFarland  R. W. McCulloch  J. B. Biggs  G. Mori  F. Morino  James W. Coulthard  M. J. Langeveld  M. L. Kellmer Pringle  M. A. Brimer  Jesse E. Gordon  T. N. Postlethwaite  W. E. Vliegenthart  Eve Malmquist  B. F. Nel  Gerhard Pause  Kurt Graff  A. Gammie  Dirk Wendt 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1963,9(4):477-506

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Lines of Freedom     

Gerhard Friedrich 《The Educational forum》2013,77(4)

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Portrait of Peter     

Gerhard Friedrich 《The Educational forum》2013,77(2)

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On the Performance of Likelihood-Based Difference Tests in Nonlinear Structural Equation Models     

Carla Gerhard  Andreas G. Klein  Karin Schermelleh-Engel  Helfried Moosbrugger  Jana Gäde  Holger Brandt 《Structural equation modeling》2013,20(2):276-287

This article investigates likelihood-based difference statistics for testing nonlinear effects in structural equation modeling using the latent moderated structural equations (LMS) approach. In addition to the standard difference statistic T_D, 2 robust statistics have been developed in the literature to ensure valid results under the conditions of nonnormality or small sample sizes: the robust T_DR and the “strictly positive” T_DRP. These robust statistics have not been examined in combination with LMS yet. In 2 Monte Carlo studies we investigate the performance of these methods for testing quadratic or interaction effects subject to different sources of nonnormality, nonnormality due to the nonlinear terms, and nonnormality due to the distribution of the predictor variables. The results indicate that T_D is preferable to both T_DR and T_DRP. Under the condition of strong nonlinear effects and nonnormal predictors, T_DR often produced negative differences and T_DRP showed no desirable power.  相似文献   

The contribution of domain-specific knowledge in predicting students' proportional word problem-solving performance     

Asha K. Jitendra  Amy E. Lein  Jon R. Star  Danielle N. Dupuis 《Educational Research and Evaluation》2013,19(8):700-716

This study explored the extent to which domain-specific knowledge predicted proportional word problem-solving performance. We tested 411 seventh-grade students on conceptual and procedural fraction knowledge, conceptual and procedural proportion knowledge, and proportional word problem solving. Multiple regression analyses indicated that all four domain-specific knowledge variables (i.e., conceptual and procedural fraction knowledge, conceptual and procedural proportion knowledge) significantly predicted proportional word problem-solving performance. Conceptual fraction and procedural proportion knowledge contributed the most unique variance (10.0 and 6.7%, respectively, of the total variance) to proportional word problem solving. Procedural fraction and conceptual proportion knowledge each also contributed significant unique variance to proportional word problem solving explaining 5.6 and 2.8%, respectively. The results support the notion that both conceptual fraction and proportion knowledge and procedural fraction and proportion knowledge play a major role in understanding individual differences in proportional word problem-solving performance to inform interventions.  相似文献   

Consultants’ Learning within Academia: Five devices for the design of university-based learning opportunities for management consultants     

Gerhard Smid 《Studies in Continuing Education》2013,35(1):55-70

This paper explores the ways in which it is possible for universities to design learning opportunities for management consultants. Drawing on a successful practice in The Netherlands and using the literature on learning, development of competencies and career theory, it investigates selected aspects of this particular “market”, comparing the conventions governing the practice of consultants with those of academic practice. Its subsequent argument for the successful design of learning opportunities for professional consultants is organised around a discussion of five learning “devices”: (1) a self-reflective design practice; (2) a design process operating along three dimensions - the acquisition of knowledge and/or techniques, development of professional competencies, and personal and professional transitions; (3) treating knowledge as a process rather than a product; (4) building on learning experiences in work and on anticipated performances; and (5) a prohibition of “ego” in consultants' learning. The paper concludes with some reflections on the use of these devices elsewhere.  相似文献   

Biology Curricula at Universities in the European Community     

Gerhard Schaefer 《International Journal of Science Education》2013,35(2):223-230

In literature, several processes have been suggested to describe conceptual changes being undertaken. However, a few parts of studies analyse in great detail which students' learning processes are involved in physics classes during teaching, and how they are used. Following a socio-constructivist approach using tools coming from discourse analysis, we suggest studying three processes of students' learning: (1) establishing links between ideas, (2) increasing the domain of applicability of ideas, or (3) decreasing the domain of applicability of ideas. Our database consists of video data and written worksheets of two students at the upper-secondary school level (Grade 10 [15-year-old students]) during a one-month teaching sequence about gas. Based on semiotic resources contained in oral and written language, we reconstruct in great detail all the ideas about gas expressed by both students during the entire teaching sequence. Our analysis deals with (1) how learning processes are identified based on the ideas expressed by students, and (2) how the three learning processes are used by the two students during teaching. Our results show that during the teaching sequence: (1) the emergence of the networks of three ideas is supported by networks of two ideas expressed previously by students; (2) both students express more networks of two ideas than networks of three ideas; (3) the process ‘increasing the domain of applicability’ of an idea or a network of ideas is very often involved; and (4) the process ‘decreasing the domain of applicability’ of an idea or network of ideas is rarely used by them.  相似文献