Verteilte Metadatenverwaltung und Anfragebearbeitung für Internet-Datenquellen     

Markus Keidl  Alfons Kemper  Donald Kossmann und Alexander Kreutz 《Informatik - Forschung und Entwicklung》2002,17(3):123-134

Zusammenfassung.   Wir pr?sentieren in dieser Arbeit das ObjectGlobe-System, ein offenes und verteiltes Anfragebearbeitungssystem auf Internet-Datenquellen. ObjectGlobe erweitert die begrenzten F?higkeiten des Internets bezüglich Anfragebearbeitung, indem es einen offenen Marktplatz schafft, in dem eine Vielzahl von Anbietern Rechenzeit, Daten und Anfrageoperatoren bereitstellen. Den Schwerpunkt dieses Beitrags bildet die im Rahmen des ObjectGlobe-Projekts entwickelte Metadatenverwaltung MDV, ein verteiltes Metadaten-Management-System. Es besitzt eine 3-schichtige Architektur und unterstützt Caching und Replikation in der Mittelschicht, so dass Anfragen lokal ausgewertet werden k?nnen. Benutzer spezifizieren die Informationen, die sie ben?tigen und die repliziert werden, mit Hilfe einer besonderen Regelsprache. Um Replikate aktuell zu halten und die Replikation von neuen und relevanten Informationen anzusto?en, verwendet das MDV-System einen neuartigen Publish & Subscribe-Algorithmus. Wir beschreiben diesen Algorithmus im Detail und zeigen, wie er mit Hilfe eines normalen relationalen Datenbanksystems implementiert werden kann. Eingegangen am 19. November 2001 / Angenommen am 30. Juli 2002  相似文献   

A topography of free kicks in soccer     

Daniel Link  Otto Kolbinger  Hendrik Weber  Michael Stöckl 《Journal of sports sciences》2016,34(24):2312-2320

ABSTRACT

This study investigates the spatial relationship of performance variables for soccer free kicks. In order to suggest ways in which players might optimise their performance, we collected data from free kicks (<35 m to goal line) of two German Bundesliga seasons (2013/14, 2014/15) (n = 1624). In the analysis, we applied the ISO-map approach using colour gradients to visualise the mean values of a variable on a 2D-map of the pitch. Additionally, variograms were used to describe the degree of spatial dependence of the free kick variables. Results show that DENSITY, TYPE OF PLAY, PLAYERS IN WALL, DISTANCE TO WALL and RULE VIOLATION were strongly spatially dependent. Centrality and proximity to the goal increased the variables PLAYERS IN WALL, RULE VIOLATIONS and INTERRUPTION TIME, and the ratio of goals scored increased from 5.9% (central far) to 10.9% (central near). In 70.9% of the shots, players preferred a switched laterality, which did not result in a higher success rate. Furthermore, there was no statistical advantage for the defensive team when DISTANCE TO WALL was below 9.15 m or when there was a RULE VIOLATION. Crosses had a success rate (i.e., first controlled ball contact after the cross) of 20.8%. Played with natural laterality, they were 5% more successful than with switched laterality. Crosses from the right side outside the penalty box were 10% more successful than from the left side. Therefore, it might be worthwhile practising the defence of balls coming from this side.  相似文献   

Modeling problem solving inquiry processes     

Paul B. Otto 《Journal of Science Teacher Education》1991,2(2):37-39

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Otto Rauh 《Informatik - Forschung und Entwicklung》1995,10(3):128-138

Zusammenfassung. Traditionelle und deduktive Informationssysteme werden heute immer noch isoliert voneinander modelliert und implementiert. Für die meisten Benutzer sind jedoch Systeme wichtig, die ihren allt?glichen Informationsbedarf decken und darüber hinaus deduktive F?higkeiten besitzen. Der bekannte Entity-Relationship-Ansatz zur konzeptionellen Datenmodellierung wird in dieser Arbeit so erweitert, da? damit solche integrierten Systeme modelliert werden k?nnen. Au?erdem wird eine Klassifizierung ableitbarer Daten eingeführt, die dem Analytiker Hilfestellung bei der Frage gibt, welche ableitbaren Daten bei der Modellierung berücksichtigt werden sollen und welche nicht. Eingegangen am 2. November 1994 / Angenommen am 30. M?rz 1995  相似文献   

Subjective reactions of students to a programed workbook for a continental classroom course     

Edward J. Robinson  Otto Lerbinger 《Educational technology research and development : ETR & D》1963,11(6):241-252

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Ball launch conditions for skilled golfers using drivers of different lengths in an indoor testing facility     

Wallace ES  Otto SR  Nevill A 《Journal of sports sciences》2007,25(7):731-737

The displacement of the golf ball struck by a driving club is affected by several player characteristics and equipment parameters and their interrelationships. Some modelling and simulation studies have shown a relationship between shaft length and clubhead speed, supported by a few experimental studies. The aim of the present study was to examine the relationship between driver length and ball launch conditions in an indoor test facility using a ball launch monitor. Nine males considered to be skilled golfers participated in the study. Four driving clubs of total length 117, 119, 124, and 132 cm were assembled from commercially available components and were used to strike golf shots while initial ball velocity, backspin rate, and launch angles were measured. Statistical analysis identified a significant difference in initial launch speed due to club length, a significant difference between participants, but no difference between the trials for a given golfer. A positive trend was noted between backspin and launch angle for all four clubs, and significant inverse associations between initial launch speed and backspin rate and launch angle. However, the combined launch conditions associated with increasing length were not considered optimal, with uncontrolled swingweight and moment of inertia effects considered to be limiting factors.  相似文献   

Curriculum development at the regional level through regional education centres     

Otto Herz 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1973,19(2):232-238

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The criterion of “relevance” in the support of research in the social sciences: 1965–1985     

Cyril S. Smith  Otto N. Larsen 《Minerva》1989,27(4):461-482

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Practical training and internships in engineering education: Educational goals and assessment     

Otto Rompelman  Jan De Vries 《European Journal of Engineering Education》2002,27(2):173-180

In many engineering curricula a period of practical training in industry is either compulsory or advised. Often the educational goals of such a period are defined as 'learning to put knowledge and skills into practice'. The assessment is usually based on a technical report of the activities during the period. In this paper, how the definition of educational objectives led to the introduction of practical training is discussed. These objectives are acquiring insight in the engineering profession, learning to 'survive' in a different culture and learning to apply as well as broadening technical knowledge and skills. Furthermore, an assessment procedure is introduced which allows for testing whether the students have met the objectives.  相似文献   

Collaborative management of business metadata     

Kai M. Hüner^{Author Vitae}  Boris Otto Author VitaeHubert Österle Author Vitae 《International Journal of Information Management》2011,31(4):366-373

Legal provisions, cross-company data exchange and intra-company reporting or planning procedures require comprehensively, timely, unambiguously and understandably specified business objects (e.g. materials, customers, and suppliers). On the one hand, this business metadata has to cover miscellaneous regional peculiarities in order to enable business activities anywhere in the world. On the other hand, data structures need to be standardized throughout the entire company in order to be able to perform global spend analysis, for example. In addition, business objects should adapt to new market conditions or regulatory requirements as quickly and consistently as possible. Centrally organized corporate metadata managers (e.g. within a central IT department) are hardly able to meet all these demands. They should be supported by key users from several business divisions and regions, who contribute expert knowledge. However, despite the advantages regarding high metadata quality on a corporate level, a collaborative metadata management approach of this kind has to ensure low effort for knowledge contributors as in most cases these regional or divisional experts do not benefit from metadata quality themselves. Therefore, the paper at hand identifies requirements to be met by a business metadata repository, which is a tool that can effectively support collaborative management of business metadata. In addition, the paper presents the results of an evaluation of these requirements with business experts from various companies and of scenario tests with a wiki-based prototype at the company Bayer CropScience AG. The evaluation shows two things: First, collaboration is a success factor when it comes to establishing effective business metadata management and integrating metadata with enterprise systems, and second, semantic wikis are well suited to realizing business metadata repositories.  相似文献