Restrukturierung objektorientierter Datenbankschemata mittels formaler Begriffsanalyse

Zusammenfassung.   Eine Restrukturierung eines gegebenen Datenbankschemas kann aus unterschiedlichen Gründen notwendig werden. So kann dadurch z.B. die Verst?ndlichkeit des Schemas verbessert werden. Im Bereich der relationalen Datenbanken steht die Normalisierungstheorie zur Verfügung, um z.B. Redundanz zu vermeiden. Der Normalisierung liegt dabei ein Begriff der ?quivalenz von Datenbankschemata zugrunde. Im Bereich der objektorientierten Datenbanken gibt es bislang kaum vergleichbare Ans?tze. In diesem Beitrag pr?sentieren wir daher einen Ansatz, mit dem Klassenhierarchien in objektorientierten Datenbankschemata in eine „normalisierte” Form transformiert werden k?nnen. Dazu mu? zun?chst eine extensionale Analyse durchgeführt werden, die die notwendigen Informationen über extensionale Beziehungen zwischen den gegebenen Klassen liefert. Anschlie?end wenden wir Konzepte der formalen Begriffsanalyse an, um eine „normalisierte” Klassenhierarchie abzuleiten. Eingegangen am 16. Januar 1999 / Angenommen am 3. Oktober 1999     

Fostering multiple text comprehension: How metacognitive strategies and motivation moderate the text-belief consistency effect

Learners often have difficulties comprehending multiple texts about controversial scientific issues. In particular, learners with strong prior beliefs tend to construct a one-sided mental representation that is biased towards belief-consistent information (text-belief consistency effect). In the present study we examined the effectiveness of information of three metacognitive strategies tailored to strengthen the comprehension of belief-inconsistent information during multiple text comprehension. According to theories of self-regulated learning, knowledge about relevant metacognitive strategies improves comprehension only when learners are also motivated to use these strategies. These hypotheses were investigated in an experiment in which 85 participants read one belief-consistent and one belief-inconsistent text about a controversial scientific issue. Participants either received information about three metacognitive strategies or no additional information. In addition, participants’ motivation was manipulated by providing them with either negative or positive performance feedback or no feedback. As predicted, a text-belief consistency effect was found, which was eliminated by strengthening the situation model for the belief-inconsistent text only when learners received information about relevant metacognitive strategies and were motivated to use these strategies after positive performance feedback.     

How to improve argumentation comprehension in university students: experimental test of a training approach

Instructional Science - The ability to comprehend informal arguments is essential for scientific literacy but students often lack structural knowledge about these arguments, especially when the...     

Assessment matters: What are students learning about sustainability?

Kimberly Yousey‐Elsener, Diana Richter Keith, and Staci Lynne Ripkey provide a model to integrate sustainability efforts, student learning, and assessment into one coherent process.     

Student resistance in the classroom—Functional‐instrumentalist,critical‐emancipatory and critical‐functional conceptualisations

The paper provides a systemic literature review and a typology of texts that discuss student resistance in the classroom in Higher Education. Analysing 134 empirical and conceptual studies published between 1988 and 2018 for how student resistance is conceptualised, this review identifies three approaches: functional‐instrumentalist, critical‐emancipatory and critical‐functional. Presenting the three approaches in more depth, the article points to the main tenets, like supposed reasons for and suggested ways of handling student resistance. In the final part of the analysis, the paper discusses the typology in light of the current institutional background of Higher Education, including the managerial university and ambivalences of critical education. Finally, the article offers future research directions.     

Ein Testverfahren für optimierende Codegeneratoren

Die im Rahmen der Modell-basierten Entwicklung eingebetteter Steuerungs- und Regelungssoftware eingesetzten optimierenden Codegeneratoren müssen einer intensiven Qualit?tssicherung unterzogen werden. Dem Einsatz von Testsuiten kommt dabei eine zentrale Rolle zu. Der Beitrag beschreibt den Aufbau einer modularen Testsuite für Codegeneratoren und schl?gt einen Testansatz vor, der eine systematische Prüfung der vom Codegenerator angewendeten Optimierungstechniken erm?glicht.     

Ethanol-glycerin fixation with thymol conservation: a potential alternative to formaldehyde and phenol embalming

Anatomical fixation and conservation are required to prevent specimens from undergoing autolysis and decomposition. While fixation is the primary arrest of the structures responsible for autolysis and decomposition, conservation preserves the state of fixation. Although commonly used, formaldehyde has been classified as carcinogenic to humans. For this reason, an adequate substitute was developed. Ethanol-glycerin fixation and thymol conservation are described and compared with formaldehyde and phenol in this technical report. The setup, tissue qualities, financial aspects, and health concerns of this method are discussed. Ethanol-glycerin fixation and thymol conservation provide outstanding haptic and optic tissue qualities. Typical formaldehyde and phenol effects, such as skin, airway, and eye irritation, as well as carcinogenic effects, can be circumvented by using ethanol-glycerin and thymol instead. Ethanol-glycerin fixation is more expensive than formaldehyde and requires an explosion-proof facility. However, the absence of health effects and its convincing tissue qualities balance these higher costs. Therefore, ethanol-glycerin fixation and thymol conservation provide a potential alternative and complement established fixation techniques. The use of carcinogenic formaldehyde and toxic phenol can be effectively restricted through the use of the described method.