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Now showing items 11-20 of 39
Aufsatz
Mining minimal non-redundant association rules using frequent closed itemsets
(2000)
The problem of the relevance and the usefulness of extracted association rules is of primary importance because, in the majority of cases, real-life databases lead to several thousands association rules with high confidence and among which are many redundancies. Using the closure of the Galois connection, we define two new bases for association rules which union is a generating set for all valid association rules with support and confidence. These bases are characterized using frequent closed itemsets and their ...
Aufsatz
CEM - a conceptual Email manager
(2000)
CEM is an email management system which stores its email in a concept lattice rather than in the usual tree structure. By using such a conceptual multi-hierarchy, the system provides more flexibility in retrieving stored emails. The paper presents the underlying mathematical structures, discusses requirements for their maintenance and presents their implementation.
Aufsatz
Exploration tools in formal concept analysis
(1996)
The development of conceptual knowledge systems specifically requests knowledge acquisition tools within the framework of formal concept analysis. In this paper, the existing tools are presented, and furhter developments are discussed.
Aufsatz
CEM - visualization and discovery in Email
(2000)
This paper presents a lattice-based visual metaphor for knowledge discovery in electronic mail. It allows a user to navigate email using a visual lattice metaphor rather than a tree structure. By using such a conceptual multi-hierarchy, the content and shape of the lattice can be varied to accommodate any number of queries against the email collection. The system provides more flexibility in retrieving stored emails and can be generalised to any electronic documents. The paper presents the underlying mathematical ...
Aufsatz
Hierarchies of conceptual scales
(1999)
Formal Concept Analysis allows to derive conceptual hierarchies from data tables. Formal Concept Analysis is applied in various domains, e.g., data analysis, information retrieval, and knowledge discovery in databases. In order to deal with increasing sizes of the data tables (and to allow more complex data structures than just binary attributes), conceputal scales habe been developed. They are considered as metadata which structure the data conceptually. But in large applications, the number of conceptual scales ...
Aufsatz
A geometrical heuristic for drawing concept lattices
(1995)
Concept lattices are used in formal concept analysis to represent data conceptually so that the original data are still recognizable. Their line diagrams should reflect the semantical relationships within the data. Up to now, no satisfactory automatic drawing programs for this task exist. The geometrical heuristic is the most successful tool for drawing concept lattices manually. It ueses a geometric representation as intermediate step between the list of upper covers and the line diagram of the lattice.
Aufsatz
Visuelle Transaktionen: Kontrolle der Nebenläufigkeit bei synchroner Gruppenarbeit
(2004)
Vortragsfolien eines im Mai 1999 auf einem Datenbankseminar (intern) gehaltenen Vortrags.
Zusammenfassung:
Der Vortrag fasst anschaulich einige der Themen zusammen, an denen das FG Datenbanken/Interaktive Systeme um das Jahr 2000 (und einige Jahre davor und danach) gearbeitet hat: Navigieren und Editieren von NF2-Tabellen mit dem DB-Editor ESCHER, das Fingerkonzept, Focus/Nimbus-Fragen, erweiterte Transaktionskonzepte für datenbankgestützte synchrone Gruppenarbeit. Die im Ausblick aufgestellte These, wonach visuelle ...
Aufsatz
Pointer Swizzling: Unterbrechung erwünscht!
(1995)
Vortragsfolien eines auf dem SAP ABAP-Jahrestreffen 20.-22.9.1995 in Ottrott/Elsaß gehaltenen Vortrags. -
Zusammenfassung:
Unter Pointer Swizzling versteht man eine Technik, persistente Zeiger in Datenbeständen zur Laufzeit so geschickt durch Hauptspeicherzeiger zu ersetzen, dass schnelles Durchlaufen komplexer Objektstrukturen möglich wird. Den Begriff umgibt ein Hauch von „Magie“, vielleicht auch wegen der Geheimniskrämerei, mit der eine Firma diese Technik in ihrem Datenbankprodukt umgibt.
Der Vortrag soll ...