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
Knowledge Management Research & Practice - Being competitive entails continuously performing product and process innovations. The acquisition of externally generated R&D is therefore... 相似文献
The sustainable development (SD) concept is based on the idea that economic and social development should be linked to the environment. However, controversies about various associated issues often arise due to the differences in protagonists’ viewpoints, depending partly on whether they focus mainly on environmental, economic, or social dimensions and partly on ideological stances related (for instance) to the optimal ways of promoting economic growth and social justice. This study investigates views of 638 Swedish upper secondary students who responded to a questionnaire probing their views of SD from two perspectives. In the first, the dimensions were separately introduced, so the respondents only had to consider one dimension at a time. In the second, the dimensions were introduced in an integrated fashion, so the respondents had to consider effects related to all three dimensions. The results strongly indicate that the students’ views and priorities concerning the dimensions depend on both the perspective and the context. Implications for teaching and learning are discussed. 相似文献
Genetic determinism can be described as the attribution of the formation of traits to genes, where genes are ascribed more causal power than what scientific consensus suggests. Belief in genetic determinism is an educational problem because it contradicts scientific knowledge, and is a societal problem because it has the potential to foster intolerant attitudes such as racism and prejudice against sexual orientation. In this article, we begin by investigating the very nature of belief in genetic determinism. Then, we investigate whether knowledge of genetics and genomics is associated with beliefs in genetic determinism. Finally, we explore the extent to which social factors such as gender, education, and religiosity are associated with genetic determinism. Methodologically, we gathered and analyzed data on beliefs in genetic determinism, knowledge of genetics and genomics, and social variables using the “Public Understanding and Attitudes towards Genetics and Genomics” (PUGGS) instrument. Our analyses of PUGGS responses from a sample of Brazilian university freshmen undergraduates indicated that (1) belief in genetic determinism was best characterized as a construct built up by two dimensions or belief systems: beliefs concerning social traits and beliefs concerning biological traits; (2) levels of belief in genetic determination of social traits were low, which contradicts prior work; (3) associations between knowledge of genetics and genomics and levels of belief in genetic determinism were low; and (4) social factors such as age and religiosity had stronger associations with beliefs in genetic determinism than knowledge. Although our study design precludes causal inferences, our results raise questions about whether enhancing genetic literacy will decrease or prevent beliefs in genetic determinism. 相似文献
This paper presents empirical evidence on the adoption, implementation and the perceived effectiveness of quality management in teaching and learning in German higher education institutions. Theoretically, the article combines two new institutionalist approaches: institutional isomorphism and institutional entrepreneurship. Empirically, the study refers to qualitative interview data and quantitative survey data. The analysis reveals that isomorphism is a leading driver behind the adoption of quality management in German higher education institutions, whereas institutional entrepreneurship plays an important role in quality management implementation. While isomorphism can be regarded as a conclusive reason behind the absence of a perception of quality management’s effectiveness, institutional entrepreneurship may function as a corrective towards the overall negative impact of isomorphic conformity by institutionalizing quality management in a sustainable manner.
The present study reports an empirical investigation into concept formation of young children. Based on interviews conducted before and after participating in a playfully enacted chemistry lesson at a culture center, it is analyzed how 6-year-old children conceptualize water, molecule, and chemistry. Theoretically, the study is informed by Vygotsky’s cultural-historical perspective on concept formation. The empirical data consist of pre- and post-interviews with children and documentation of their participation in the intermediate activity. This documentation is used in the post-interviews as a mutual ground for talking with the children about what they remember and how they understand the activity they participated in and what the activity intended to illustrate. The results are presented in terms of three inductively generated categories: ‘everyday’, ‘experientially-based’, and ‘generalized experiences’ concepts, respectively. The implications of these findings for early childhood chemistry (science) education are discussed.
This study examined the psychometric properties of the Sexual Orientation Counselor Competency Scale (SOCCS), an instrument that measures the attitudes, skills, and knowledge of counselors who work with lesbian, gay, and bisexual individuals. Internal consistency of the SOCCS was .90, and 1‐week test‐retest reliability was .84. Criterion, concurrent, and divergent validity tests established the SOCCS as a psychometrically sound instrument. 相似文献
Skiing manufacturers depend on the development of new skis on trial and error cycles and extensive product testing. Simulation
tools, such as the finite element method, might be able to reduce the number of required testing cycles. However, computer
programs simulating a ski in the situation of a turn so far lack realistic ski–snow interaction models. The aim of this study
was to (a) implement a finite element simulation of a ski in a carved turn with an experimentally validated ski–snow interaction
model, and (b) comparison of the simulation results with instantaneous turn radii determined for an actual carved turn. A
quasi-static approach was chosen in which the ski–snow interaction was implemented as a boundary condition on the running
surface of the ski. A stepwise linear function was used to characterise the snow pressure resisting the penetration of the
ski. In a carved turn the rear section of the ski interacts with the groove that forms in the snow. Two effects were incorporated
in the simulation to model this situation: (a) the plasticity of the snow deformation, (b) the influence of the ski’s side-cut
on the formation and shape of this groove. The simulation results agreed well with experiments characterising snow penetration.
Implementation of the groove in the ski–snow interaction model allowed calculation of the instantaneous turn radii measured
in actual turns, but also caused significant numerical instability. The simulation contributes to the understanding of the
mechanical aspects of the ski–snow interaction in carved turns and can be used to evaluate new ski designs. 相似文献
Instructional Science - Extensive research has established that successful learning from an example is conditional on an important learning activity: self-explanation. Moreover, a model for... 相似文献
Decades of research produced inconsistent findings on whether study time can lead to achievement gains in mathematics. Data generated by more than six thousand students from three different countries who solved more than 1.1 million problem sets using a dedicated mathematics software are analyzed regarding the effect of study time on students’ achievements in mathematics. Results showed that more study time led to higher performance scores in mathematics. Further analyses revealed that low-performing students in the first school year (2017-2018) who increased their study time in the following year (2018-2019) revealed greatest gains in performance in the same school year (2018-2019) and even in the year after (2019-2020). Finally, results replicated previous observations of robust performance scores within students over the three school years, with performance scores in 2017-2018 predicting those of 2018-2019 which predicted those of 2019-2020. These results support the idea that students, in particular low-performing students, can boost their academic abilities to upper levels when increasing their study time.
