Verteilte Metadatenverwaltung und Anfragebearbeitung für Internet-Datenquellen

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.     

ASSESSING STUDENTS’ EXPERIMENTATION PROCESSES IN <Emphasis Type="Italic">GUIDED INQUIRY</Emphasis>

In recent science education, experimentation features ever more strongly as a method of inquiry in science classes rather than as a means to illustrate phenomena. Ideas and materials to teach inquiry abound. Yet, tools for assessing students’ achievement in their processes of experimentation are lacking. The present study assumes a basal, non-exclusive process model of inquiry in experimentation that can be considered a consensus from multiple approaches: (1) finding an idea/hypothesis, (2) planning and conducting an experiment, and (3) drawing conclusions from evidence. The study confronted 339 secondary level students with three guided inquiry experimentation tasks on 3 days. Selected working groups were videotaped while experimenting. All the students reported their processes in a structured report form simultaneous to their progress. The generated videos and reports were analysed in a two-stepped way: (1) Experimentation was coded according to the process model into process plots; on basis of these, (2) process-focused performance scores were calculated considering logical coherence and immediacy of the inquiry processes. Correlative analyses show for two of the tasks that the report format yielded comparable performance scores to those generated from video data after students have had opportunity to learn the surveying formats (r _S?>?.80). A first suggestion of a process-oriented assessment tool for inquiry in experimentation can be drawn from this study. It might be used to inform and complement secondary science instruction.     

The psycho-social adjustment of gifted children in middle-childhood

The psycho-social adjustment of 50 gifted (mean IQ=127) and 50 German ten-year-olds of average intelligence (mean IQ=106, matched individually on socio-economic status and gender) was compared. Data from different sources (children, parents, teachers) on social behaviour, (therapy-relevant) behaviour problems, and emotional stability revealed no significant differences between the two ability groups. Gifted elementary-school children are socially and emotionally at least as well adjusted as their non-gifted age-mates.     

Notes on Authors

In research on giftedness, small samples are the rule rather than the exception. Such samples require an especially meticulous research design. The absence of power‐analytical considerations (Le., defining the minimal sample sizes according to a‐ and β ‐error and expected effects) prior to data gathering can easily lead to false conclusions based on faulty data interpretation. Especially with smaller samples, it is strongly recommended that practical relevance (employing a suitable index of effect strength) be taken into consideration when interpreting observed group differences. This is better than relying on “statistical significance” alone. Group studies should not be conducted with extremely small samples. According to a proven “rule of thumb”, each subgroup tested should be comprised of at least 20 to 25 subjects. Because of the prevalence of small sample studies in research on giftedness (gifted individuals are by definition rare), it is important that statistical analyses be conducted in ways which are capable of detecting “significant” effects and which are not, for instance because of small sample size, predestined to conclude that no effects are present, even when they are (i.e., to accept the null hypothesis, even when it is false). The nature of the problem can be made more concrete by looking at a practical example taken from an article of Gefferth and Herskovits (1991).     

Reading comprehension: skill or skills?

Research on the complexity of reading comprehension is highly controversial. In spite of the evidence for a holistic reading comprehension of skilled readers, reading specialists and teachers argue that early reading comprehension is composed of different separate subskills. To investigate this, 38 German reading tests (covering many different aspects of reading comprehension), one spelling test and one speed-of-information-processing test were administered to 220 German second graders (114 girls, 106 boys). The frequency distribution of the 780 correlation coefficients indicated a very homogeneous structure. Taking into account critical points in the design of dimension analytical studies, a principal component analysis (principal axis extraction) led to only one broad general reading comprehension component, accounting for 61% of the total variance (56% for girls, 65% for boys). Reading comprehension of early readers thus appears to be holistic, closely related to general intelligence and verbal problem solving.     

Undisclosed desires: quality managers’ normative notions regarding the implementation of quality management

Following decades of quality management featuring in higher education settings, questions regarding its implementation, impact and outcomes remain. Indeed, leaving aside anecdotal case studies and value-laden documentaries of best practice, current research still knows very little about the implementation of quality management in teaching and learning within higher education institutions. Referring to data collected from German higher education institutions in which a quality management department or functional equivalent was present, this article theorises and provides evidence for the supposition that the implementation of quality management follows two implicit logics. Specifically, it tends either towards the logic of appropriateness or, contrastingly, towards the logic of consequentialism. This study’s results also suggest that quality managers’ socialisation is related to these logics and that it influences their views on quality management in teaching and learning.     

Teacher humor: longitudinal effects on students’ emotions

European Journal of Psychology of Education - Characteristics of teaching are associated with the emotions students experience in the classroom; however, empirical evidence regarding longitudinal...     

STUDENTS’ WAYS OF REASONING ABOUT NONLINEAR FUNCTIONS IN GUESS-MY-RULE GAMES

There is a growing movement toward the introduction of algebra in early grades. This is supported by an increasing number of research studies that have reported success in getting young students to “do” mathematics considered beyond their reach. Yet, the consensus is that more research is needed to provide insights into the processes by which students make sense of algebraic ideas. In particular, more studies are needed on how nonlinear functions can be introduced in early grades. This article reports an algebra research strand that introduced seventh grade students to quadratic functions using Guess-My-Rule games. The article describes several instances of the students engaging successfully with ideas and forms of reasoning involving quadratic functions. The purpose is to contribute to the debate on the introduction of algebra in early grades by providing further evidence of young students’ ability to engage with algebraic ideas usually considered to be beyond their reach.     

Active ingredients and factors for deep processing during an example-based training intervention

Learning Environments Research - In two experiments with German secondary school students (N1 = 43; N2 = 41), we aimed to analyze and optimize an effective learning...     

Dimensional comparisons in subject-specific academic self-concepts and achievements: A quasi-experimental approach

Even though marks in different subjects are substantially correlated, the corresponding self-concepts often display a very weak association. The “Internal–External Frame of Reference Model” (I/E-model; Marsh, H. W. (1986). Verbal and math self-concepts: an internal/external frame of reference model. American Educational Research Journal, 23, 129–149) explains this finding: social comparisons (resulting in positive correlations of the self-concepts) and dimensional comparisons (resulting in negative correlations of the self-concepts) are confounded. A rarely tested hypothesis derived from the I/E-model is that the dimensional comparison process only affects the self-concepts, if the students achieve differently in the corresponding subjects. In a sample of N = 1508 students (grades 7 and 8), low correlations of the self-concepts for four subjects could be observed only in students displaying different school-marks in the corresponding subjects. In students who have the same marks in different subjects, the self-concepts showed a substantial positive correlation.