eLearning and Semantic Web

Semantic Web: Software agents on the Semantic Web may use commonly agreed service language, which enables co-ordination between agents and proactive delivery of learning materials in the context of actual problems. The vision is that each user has his own personalized agent that communicates with other agents.

Automatische Dienstvermittlung in dienstorientierten Architekturen

Die Technologie dienstorientierter Architekturen (Service-oriented Architectures, kurz SOA) weckt große Visionen auf Seiten der Industrie wie auch der Forschung. Sie hat sich als derzeit ideale Lösung für Umgebungen, in denen sich die Anforderungen an die IT-Bedürfnisse rapide ändern, erwiesen. Heutige IT-Systeme müssen Managementaufgaben wie Softwareinstallation, -anpassung oder -austausch erlauben, ohne dabei den laufenden Betrieb wesentlich zu stören. Die dafür nötige Flexibilität bieten dienstorientierte Architekturen, in denen Softwarekomponenten in Form von Diensten zur Verfügung stehen. Ein Dienst bietet über seine Schnittstelle lokalen wie entfernten Applikationen einen Zugang zu seiner Funktionalität. Wir betrachten im Folgenden nur solche dienstorientierte Architekturen, in denen Dienste zur Laufzeit dynamisch entdeckt, gebunden, komponiert, verhandelt und adaptiert werden können. Eine Applikation kann mit unterschiedlichen Diensten arbeiten, wenn beispielsweise Dienste ausfallen oder ein neuer Dienst die Anforderungen der Applikation besser erfüllt. Eine unserer Grundvoraussetzungen lautet somit, dass sowohl das Dienstangebot als auch die Nachfrageseite variabel sind. Dienstorientierte Architekturen haben besonderes Gewicht in der Implementierung von Geschäftsprozessen. Im Rahmen des Paradigmas Enterprise Integration Architecture werden einzelne Arbeitsschritte als Dienste implementiert und ein Geschäftsprozess als Workflow von Diensten ausgeführt. Eine solche Dienstkomposition wird auch Orchestration genannt. Insbesondere für die so genannte B2B-Integration (Business-to-Business) sind Dienste das probate Mittel, um die Kommunikation über die Unternehmensgrenzen hinaus zu unterstützen. Dienste werden hier in der Regel als Web Services realisiert, welche vermöge BPEL4WS orchestriert werden. Der XML-basierte Nachrichtenverkehr und das http-Protokoll sorgen für eine Verträglichkeit zwischen heterogenen Systemen und eine Transparenz des Nachrichtenverkehrs. Anbieter dieser Dienste versprechen sich einen hohen Nutzen durch ihre öffentlichen Dienste. Zum einen hofft man auf eine vermehrte Einbindung ihrer Dienste in Softwareprozesse. Zum anderen setzt man auf das Entwickeln neuer Software auf Basis ihrer Dienste. In der Zukunft werden hunderte solcher Dienste verfügbar sein und es wird schwer für den Entwickler passende Dienstangebote zu finden. Das Projekt ADDO hat in diesem Umfeld wichtige Ergebnisse erzielt. Im Laufe des Projektes wurde erreicht, dass der Einsatz semantischer Spezifikationen es ermöglicht, Dienste sowohl im Hinblick auf ihre funktionalen als auch ihre nicht-funktionalen Eigenschaften, insbesondere die Dienstgüte, automatisch zu sichten und an Dienstaggregate zu binden [15]. Dazu wurden Ontologie-Schemata [10, 16], Abgleichalgorithmen [16, 9] und Werkzeuge entwickelt und als Framework implementiert [16]. Der in diesem Rahmen entwickelte Abgleichalgorithmus für Dienstgüte beherrscht die automatische Aushandlung von Verträgen für die Dienstnutzung, um etwa kostenpflichtige Dienste zur Dienstnutzung einzubinden. ADDO liefert einen Ansatz, Schablonen für Dienstaggregate in BPEL4WS zu erstellen, die zur Laufzeit automatisch verwaltet werden. Das Vorgehen konnte seine Effektivität beim internationalen Wettbewerb Web Service Challenge 2006 in San Francisco unter Beweis stellen: Der für ADDO entwickelte Algorithmus zur semantischen Dienstkomposition erreichte den ersten Platz. Der Algorithmus erlaubt es, unter einer sehr großenMenge angebotener Dienste eine geeignete Auswahl zu treffen, diese Dienste zu Dienstaggregaten zusammenzufassen und damit die Funktionalität eines vorgegebenen gesuchten Dienstes zu leisten. Weitere Ergebnisse des Projektes ADDO wurden auf internationalen Workshops und Konferenzen veröffentlicht. [12, 11]

The Courseware Watchdog: an ontology-based tool for finding and organizing learning material

Topics in education are changing with an ever faster pace. E-Learning resources tend to be more and more decentralised. Users need increasingly to be able to use the resources of the web. For this, they should have tools for finding and organizing information in a decentral way. In this, paper, we show how an ontology-based tool suite allows to make the most of the resources available on the web.

Ontology merging with formal concept analysis

Ontologies have been established for knowledge sharing and are widely used as a means for conceptually structuring domains of interest. With the growing usage of ontologies, the problem of overlapping knowledge in a common domain becomes critical. In this short paper, we address two methods for merging ontologies based on Formal Concept Analysis: FCA-Merge and ONTEX. --- FCA-Merge is a method for merging ontologies following a bottom-up approach which offers a structural description of the merging process. The method is guided by application-specific instances of the given source ontologies. We apply techniques from natural language processing and formal concept analysis to derive a lattice of concepts as a structural result of FCA-Merge. The generated result is then explored and transformed into the merged ontology with human interaction. --- ONTEX is a method for systematically structuring the top-down level of ontologies. It is based on an interactive, top-down- knowledge acquisition process, which assures that the knowledge engineer considers all possible cases while avoiding redundant acquisition. The method is suited especially for creating/merging the top part(s) of the ontologies, where high accuracy is required, and for supporting the merging of two (or more) ontologies on that level.

Managing Quality Properties of Web Service Compositions

Web services from different partners can be combined to applications that realize a more complex business goal. Such applications built as Web service compositions define how interactions between Web services take place in order to implement the business logic. Web service compositions not only have to provide the desired functionality but also have to comply with certain Quality of Service (QoS) levels. Maximizing the users' satisfaction, also reflected as Quality of Experience (QoE), is a primary goal to be achieved in a Service-Oriented Architecture (SOA). Unfortunately, in a dynamic environment like SOA unforeseen situations might appear like services not being available or not responding in the desired time frame. In such situations, appropriate actions need to be triggered in order to avoid the violation of QoS and QoE constraints. In this thesis, proper solutions are developed to manage Web services and Web service compositions with regard to QoS and QoE requirements. The Business Process Rules Language (BPRules) was developed to manage Web service compositions when undesired QoS or QoE values are detected. BPRules provides a rich set of management actions that may be triggered for controlling the service composition and for improving its quality behavior. Regarding the quality properties, BPRules allows to distinguish between the QoS values as they are promised by the service providers, QoE values that were assigned by end-users, the monitored QoS as measured by our BPR framework, and the predicted QoS and QoE values. BPRules facilitates the specification of certain user groups characterized by different context properties and allows triggering a personalized, context-aware service selection tailored for the specified user groups. In a service market where a multitude of services with the same functionality and different quality values are available, the right services need to be selected for realizing the service composition. We developed new and efficient heuristic algorithms that are applied to choose high quality services for the composition. BPRules offers the possibility to integrate multiple service selection algorithms. The selection algorithms are applicable also for non-linear objective functions and constraints. The BPR framework includes new approaches for context-aware service selection and quality property predictions. We consider the location information of users and services as context dimension for the prediction of response time and throughput. The BPR framework combines all new features and contributions to a comprehensive management solution. Furthermore, it facilitates flexible monitoring of QoS properties without having to modify the description of the service composition. We show how the different modules of the BPR framework work together in order to execute the management rules. We evaluate how our selection algorithms outperform a genetic algorithm from related research. The evaluation reveals how context data can be used for a personalized prediction of response time and throughput.

Instant Storyboarding

This thesis aims at empowering software customers with a tool to build software tests them selves, based on a gradual refinement of natural language scenarios into executable visual test models. The process is divided in five steps: 1. First, a natural language parser is used to extract a graph of grammatical relations from the textual scenario descriptions. 2. The resulting graph is transformed into an informal story pattern by interpreting structurization rules based on Fujaba Story Diagrams. 3. While the informal story pattern can already be used by humans the diagram still lacks technical details, especially type information. To add them, a recommender based framework uses web sites and other resources to generate formalization rules. 4. As a preparation for the code generation the classes derived for formal story patterns are aligned across all story steps, substituting a class diagram. 5. Finally, a headless version of Fujaba is used to generate an executable JUnit test. The graph transformations used in the browser application are specified in a textual domain specific language and visualized as story pattern. Last but not least, only the heavyweight parsing (step 1) and code generation (step 5) are executed on the server side. All graph transformation steps (2, 3 and 4) are executed in the browser by an interpreter written in JavaScript/GWT. This result paves the way for online collaboration between global teams of software customers, IT business analysts and software developers.

Reasoning about Temporal Context using Ontology and Abductive Constraint Logic Programming

The underlying assumptions for interpreting the meaning of data often change over time, which further complicates the problem of semantic heterogeneities among autonomous data sources. As an extension to the COntext INterchange (COIN) framework, this paper introduces the notion of temporal context as a formalization of the problem. We represent temporal context as a multi-valued method in F-Logic; however, only one value is valid at any point in time, the determination of which is constrained by temporal relations. This representation is then mapped to an abductive constraint logic programming framework with temporal relations being treated as constraints. A mediation engine that implements the framework automatically detects and reconciles semantic differences at different times. We articulate that this extended COIN framework is suitable for reasoning on the Semantic Web.

Reasoning about Temporal Context using Ontology and Abductive Constraint Logic Programming

The underlying assumptions for interpreting the meaning of data often change over time, which further complicates the problem of semantic heterogeneities among autonomous data sources. As an extension to the COntext INterchange (COIN) framework, this paper introduces the notion of temporal context as a formalization of the problem. We represent temporal context as a multi-valued method in F-Logic; however, only one value is valid at any point in time, the determination of which is constrained by temporal relations. This representation is then mapped to an abductive constraint logic programming framework with temporal relations being treated as constraints. A mediation engine that implements the framework automatically detects and reconciles semantic differences at different times. We articulate that this extended COIN framework is suitable for reasoning on the Semantic Web.

Reasoning about Temporal Context using Ontology and Abductive Constraint Logic Programming

The underlying assumptions for interpreting the meaning of data often change over time, which further complicates the problem of semantic heterogeneities among autonomous data sources. As an extension to the COntext INterchange (COIN) framework, this paper introduces the notion of temporal context as a formalization of the problem. We represent temporal context as a multi-valued method in F-Logic; however, only one value is valid at any point in time, the determination of which is constrained by temporal relations. This representation is then mapped to an abductive constraint logic programming framework with temporal relations being treated as constraints. A mediation engine that implements the framework automatically detects and reconciles semantic differences at different times. We articulate that this extended COIN framework is suitable for reasoning on the Semantic Web.

Reasoning about Temporal Context using Ontology and Abductive Constraint Logic Programming

The underlying assumptions for interpreting the meaning of data often change over time, which further complicates the problem of semantic heterogeneities among autonomous data sources. As an extension to the COntext INterchange (COIN) framework, this paper introduces the notion of temporal context as a formalization of the problem. We represent temporal context as a multi-valued method in F-Logic; however, only one value is valid at any point in time, the determination of which is constrained by temporal relations. This representation is then mapped to an abductive constraint logic programming framework with temporal relations being treated as constraints. A mediation engine that implements the framework automatically detects and reconciles semantic differences at different times. We articulate that this extended COIN framework is suitable for reasoning on the Semantic Web.

COMP3016 Web Technology - Strand 3 "History" Lecture 4

Lecture 4: Ontological Hypertext and the Semantic Web Contains Powerpoint Lecture slides and Hypertext Research Papers: Conceptual linking: Ontology-based Open Hypermedia (Carr et al. 2001); CS AKTiveSpace: Building a Semantic Web Application (Glaser et al., 2004); The Semantic Web Revisited (Shadbolt, Hall and Berners-Lee, 2006); Mind the Semantic Gap (Millard et al., 2005).

TU Graz: Course: 707.000 Web Science and Web Technology: Lecture 13: Web Technologies 2 - The Semantic Web

The semantic web represents a current research effort to increase the capability of machines to make sense of content on the web. In this class, Peter Scheir will give a guest lecture on the basic principles underlying the semantic web vision, including RDF, OWL and other standards.

INFO2009 2012-13 Resource Group 13

This contains files from the resource: Semantic Web Explained by Group 13: Web Club 7 Further instructions in readme.txt