004 Datenverarbeitung; Informatik
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We aim to demonstrate that automated deduction techniques, in particular those following the model computation paradigm, are very well suited for database schema/query reasoning. Specifically, we present an approach to compute completed paths for database or XPath queries. The database schema and a query are transformed to disjunctive logic programs with default negation, using a description logic as an intermediate language. Our underlying deduction system, KRHyper, then detects if a query is satisfiable or not. In case of a satisfiable query, all completed paths -- those that fulfill all given constraints -- are returned as part of the computed models. The purpose of our approach is to dramatically reduce the workload on the query processor. Without the path completion, a usual XML query processor would search the database for solutions to the query. In the paper we describe the transformation in detail and explain how to extract the solution to the original task from the computed models. We understand this paper as a first step, that covers a basic schema/query reaÂsoning task by model-based deduction. Due to the underlying expressive logic formalism we expect our approach to easily adapt to more sophisticated problem settings, like type hierarchies as they evolve within the XML world.
We present the user-centered, iterative design of Mobile Facets, a mobile application for the faceted search and exploration of a large, multi-dimensional data set of social media on a touchscreen mobile phone. Mobile Facets provides retrieval of resources such as places, persons, organizations, and events from an integration of different open social media sources and professional content sources, namely Wikipedia, Eventful, Upcoming, geo-located Flickr photos, and GeoNames. The data is queried live from the data sources. Thus, in contrast to other approaches we do not know in advance the number and type of facets and data items the Mobile Facets application receives in a specific contextual situation. While developingrnMobile Facets, we have continuously evaluated it with a small group of fifive users. We have conducted a task-based, formative evaluation of the fifinal prototype with 12 subjects to show the applicability and usability of our approach for faceted search and exploration on a touchscreen mobile phone.
The way information is presented to users in online community platforms has an influence on the way the users create new information. This is the case, for instance, in question-answering fora, crowdsourcing platforms or other social computation settings. To better understand the effects of presentation policies on user activity, we introduce a generative model of user behaviour in this paper. Running simulations based on this user behaviour we demonstrate the ability of the model to evoke macro phenomena comparable to the ones observed on real world data.
Colonoscopy is one of the best methods for screening colon cancer. As the automatic detection of polyps in endoscopic images is a challenging task for image processing, a variety of research groups have proposed methods that try to fulfill this task to develop a system which supports the doctors during examination. However, the problem is still "at least partially" not solved. This paper gives a summary of 16 different polyp detection methods published in the last ten years. We found out that the major draw-back of many approaches is the lack of representative video data, which hinders comparison and evaluation of the published methods.
Various best practices and principles guide an ontology engineer when modeling Linked Data. The choice of appropriate vocabularies is one essential aspect in the guidelines, as it leads to better interpretation, querying, and consumption of the data by Linked Data applications and users.
In this paper, we present the various types of support features for an ontology engineer to model a Linked Data dataset, discuss existing tools and services with respect to these support features, and propose LOVER: a novel approach to support the ontology engineer in modeling a Linked Data dataset. We demonstrate that none of the existing tools and services incorporate all types of supporting features and illustrate the concept of LOVER, which supports the engineer by recommending appropriate classes and properties from existing and actively used vocabularies. Hereby, the recommendations are made on the basis of an iterative multimodal search. LOVER uses different, orthogonal information sources for finding terms, e.g. based on a best string match or schema information on other datasets published in the Linked Open Data cloud. We describe LOVER's recommendation mechanism in general and illustrate it alongrna real-life example from the social sciences domain.
In this paper we describe a series of projects on location based and personalised information systems. We start wit a basic research project and we show how we came with the help of two other more application oriented project to a product. This is developed by a consortium of enterprises and it already is in use in the city of Koblenz.
The Living Book is a system for the management of personalized and scenario specific teaching material. The main goal of the system is to support the active, explorative and selfdetermined learning in lectures, tutorials and self study. The Living Book includes a course on 'logic for computer scientists' with a uniform access to various tools like theorem provers and an interactive tableau editor. It is routinely used within teaching undergraduate courses at our university. This paper describes the Living Book and the use of theorem proving technology as a core component in the knowledge management system (KMS) of the Living Book. The KMS provides a scenario management component where teachers may describe those parts of given documents that are relevant in order to achieve a certain learning goal. The task of the KMS is to assemble new documents from a database of elementary units called 'slices' (definitions, theorems, and so on) in a scenario-based way (like 'I want to prepare for an exam and need to learn about resolution'). The computation of such assemblies is carried out by a model-generating theorem prover for first-order logic with a default negation principle. Its input consists of meta data that describe the dependencies between different slices, and logic-programming style rules that describe the scenario-specific composition of slices. Additionally, a user model is taken into account that contains information about topics and slices that are known or unknown to a student. A model computed by the system for such input then directly specifies the document to be assembled. This paper introduces the elearning context we are faced with, motivates our choice of logic and presents the newly developed calculus used in the KMS.
Knowledge compilation is a common technique for propositional logic knowledge bases. A given knowledge base is transformed into a normal form, for which queries can be answered efficiently. This precompilation step is expensive, but it only has to be performed once. We apply this technique to concepts defined in the Description Logic ALC. We introduce a normal form called linkless normal form for ALC concepts and discuss an efficient satisability test for concepts given in this normal form. Furthermore, we will show how to efficiently calculate uniform interpolants of precompiled concepts w.r.t. a given signature.
Der Fachbereich 4: Informatik der Universität Koblenz-Landau bietet seit seiner Gründung 1990 wissenschaftliche Studiengänge (Diplom) in Informatik mit verschiedenen Schwerpunkten, darunter Wirtschaft- und Verwaltungsinformatik an, dem nach und nach weitere Studiengänge zur Seite gestellt wurden: seit 1997 Computervisualistik (Diplom) und seit 2000 Informationsmanagement (Bachelor und Master). Der Fachbereich 4: Informatik hat zum Wintersemester 2006/2007 sein Lehrangebot in den Nicht-Lehramtsstudiengängen vollständig auf konsekutive Bachelor- und Masterstudiengänge umgestellt. Die Akkreditierung erfolgte über die Akkreditierungsagentur ASIIN. Die Aufnahme von Studienanfängern für die bis dahin angebotenen Diplomstudiengänge "Informatik" bzw. "Computervisualistik" wurde gleichzeitig eingestellt, und diese wurden durch ein integriertes Programm mit zwei konsekutiven Bachelor-Master-Studienprogrammen in "Informatik" und "Computervisualistik" ersetzt. Das bereits bestehende Bachelor-Master-Programm in "Informationsmanagement" wurde reformiert, und ein weiterer Masterstudiengang in "Wirtschaftsinformatik" wurde eingerichtet. Bei der Konzeption dieser sieben Studiengänge wurde auf eine hohe Integration und Studiengangs-übergreifende Wiederverwendung von Modulen geachtet. Die in diesem Papier vorgestellten Studiengänge für das Lehramt wurden schon bei der damaligen Planung mit einbezogen. Da mit Prof. Dr. Stefan Müller der Leiter der Landesarbeitsgruppe zur Erarbeitung der curricularen Standards für das Fach Informatik bei der Planung eng mit eingebunden war, konnten die Module der Bachelor- und Masterstudiengänge von Anfang an im Hinblick auf eine spätere Verwendung auch im Lehramt konzipiert werden.
ERP-Systeme stellen einen wichtigen Kompetenzbereich der Forschungsgruppe Betriebliche Anwendungssysteme (FG BAS) am Institut für Wirtschafts- und Verwaltungsinformatik (IWVI) der Universität Koblenz-Landau dar. In enger Zusammenarbeit mit Partnern aus Wirtschaft und Wissenschaft vermittelt die Forschungsgruppe sowohl Grundlagenforschung als auch praxisbezogenes Wissen an Studierende und Unternehmen. Der vorliegende Arbeitsbericht "Künftige Anforderungen an ERP-Systeme: Deutsche Anbieter im Fokus" beleuchtet auf vier Ebenen die Architektur, die verwendete Technologie, die praktischen Einsatzmöglichkeiten und die allgemeine Marktsituation aktueller ERP-Systeme auf dem deutschsprachigen Markt. Ein besonderer Dank geht in diesem Zusammenhang an Peter Herzog (zum damaligen Zeitpunkt Marketingleiter der Bison AG), der die Idee einer solchen Untersuchung hatte und die FG BAS mit deren Durchführung betraute. Die Studie wurde vom Sommer 2007 bis zum Frühling 2008 von Norbert Frick im Rahmen seiner Diplomarbeit im Fach Informatik durchgeführt. Die Auswertung der Ergebnisse wurde inhaltlich und wissenschaftlich betreut von Prof. Dr. Petra Schubert. Die Arbeit entstand aufgrund von Literaturrecherchen, schriftlichen Umfragen und Telefoninterviews mit ERPAnbietern.
Dieses Dokument schlägt ein Konzept für eine Personal Key Infrastruktur in iCity vor. Über ein Trust Center (TC) ausgestellte Zertiffkate gewährleisten einen sicheren Schlüsselaustausch mit nachweisbarer Authentisierung des Kommunikationspartners, Abhörsicherheit sowie Unverf älschtheit und Nachweisbarkeit der Nachrichten. Das gemeinsam vertrauensw ürdige TC muss während der Kommunikation nicht erreichbar sein. Es erhält lediglich öffentliche Informationen. Das Konzept stellt mehrere Sicherheitsstufen vor, die sichere Identiffkation und Anonymität unterschiedlich gewichten.
Knowledge compilation is a common technique for propositional logic knowledge bases. The idea is to transform a given knowledge base into a special normal form ([MR03],[DH05]), for which queries can be answered efficiently. This precompilation step is very expensive but it only has to be performed once. We propose to apply this technique to knowledge bases defined in Description Logics. For this, we introduce a normal form, called linkless concept descriptions, for ALC concepts. Further we present an algorithm, based on path dissolution, which can be used to transform a given concept description into an equivalent linkless concept description. Finally we discuss a linear satisfiability test as well as a subsumption test for linkless concept descriptions.
Iterative Signing of RDF(S) Graphs, Named Graphs, and OWL Graphs: Formalization and Application
(2013)
When publishing graph data on the web such as vocabulariesrnusing RDF(S) or OWL, one has only limited means to verify the authenticity and integrity of the graph data. Today's approaches require a high signature overhead and do not allow for an iterative signing of graph data. This paper presents a formally defined framework for signing arbitrary graph data provided in RDF(S), Named Graphs, or OWL. Our framework supports signing graph data at different levels of granularity: minimum self-contained graphs (MSG), sets of MSGs, and entire graphs. It supports for an iterative signing of graph data, e. g., when different parties provide different parts of a common graph, and allows for signing multiple graphs. Both can be done with a constant, low overhead for the signature graph, even when iteratively signing graph data.
IT-Sicherheitsmodelle
(2008)
Es wird erklärt, was ein Beschreibungsmodell ist, wie IT-Sicherheitsmodelle grundsätzlich aufgebaut sind und welchem Zweck sie dienen. Zur Illustration werden vier verschiedene IT-Sicherheitsmodelle vorgestellt, die historisch zu unterschiedlichen Zeiten entstanden sind. Sie passen zu vier verschiedenen typischen Anwendungsumgebungen und charakterisieren die zugehörigen Sicherheitsanforderungen. Vorgestellt werden das Bell-LaPadula-Modell zum Vertraulichkeitsschutz in hierarchischen Institutionen, das Clark-Wilson-Modell zum Integri-tätsschutz von Geschäftsanwendungen, das Chinese-Wall-Modell zum Konkurrentenschutz von Unternehmen und das Gleichgewichtsmodell zum Schutz verbindlichen Handelns im offenen Internet.
Integration von CRM-Systemen mit Kollaborations-Systemen am Beispiel von DocHouse und Lotus Quickr
(2012)
Der vorliegende Arbeitsbericht "Integration von CRM-Systemen mit Kollaborations-Systemen am Beispiel von DocHouse/ BRM und IBM Lotus Quickr" ist Ergebnis einer studentischen Projektarbeit. Ziel des Projekts war es Integrationsszenarien zwischen einem CRM-System und einem Kollaborati-onssystem zu erarbeiten und eine prototypische Schnittstelle mit entsprechender Funktion zwischen den Systemen DocHouse/ BRM und IBM Lotus Quickr zu implementieren.
Ein besonderer Dank geht in diesem Zusammenhang an Herr Wolfgang Brugger (Geschäftsführer der DocHouse GmbH), der die Idee einer solchen Entwicklung hatte und die FG BAS mit deren Durchführung betraute. Die Erstellung des Konzepts und des Prototyps wurde vom Winter 2010 bis Sommer 2011 von den Studenten Björn Lilge, Ludwig Paulsen, Marco Wolf, Markus Aldenhövel, Martin Surrey und Mike Reuthers im Rahmen ihres Projektpraktikums durchgeführt. Das Projektteam wurde bei der Konzeption und Implementierung inhaltlich und organisatorisch von Dipl.-Wirt.-Inform. Roland Diehl betreut.
With the Multimedia Metadata Ontology (M3O), we have developed a sophisticated model for representing among others the annotation, decomposition, and provenance of multimedia metadata. The goal of the M3O is to integrate the existing metadata standards and metadata formats rather than replacing them. To this end, the M3O provides a scaffold needed to represent multimedia metadata. Being an abstract model for multimedia metadata, it is not straightforward how to use and specialize the M3O for concrete application requirements and existing metadata formats and metadata standards. In this paper, we present a step-by-step alignment method describing how to integrate and leverage existing multimedia metadata standards and metadata formats in the M3O in order to use them in a concrete application. We demonstrate our approach by integrating three existing metadata models: the Core Ontology on Multimedia (COMM), which is a formalization of the multimedia metadata standard MPEG-7, the Ontology for Media Resource of the W3C, and the widely known industry standard EXIF for image metadata