Ontology-Based Information Sharing in Weakly Structured Environments

Harmelen, F.A.H. van [Promotor]Herzog, O. [Copromotor

Organising knowledge in the age of the semantic web: a study of the commensurability of ontologies

 This study is directed towards the problem of conceptual translation across different data management systems and formats, with a particular focus on those used in the emerging world of the Semantic Web. Increasingly, organisations have sought to connect information sources and services within and beyond their enterprise boundaries, building upon existing Internet facilities to offer improved research, planning, reporting and management capabilities. The Semantic Web is an ambitious response to this growing demand, offering a standards-based platform for sharing, linking and reasoning with information. The imagined result, a globalised knowledge network formed out of mutually referring data structures termed "ontologies", would make possible new kinds of queries, inferences and amalgamations of information. Such a network, though, is premised upon large numbers of manually drawn links between these ontologies. In practice, establishing these links is a complex translation task requiring considerable time and expertise; invariably, as ontologies and other structured information sources are published, many useful connections are neglected. To combat this, in recent years substantial research has been invested into "ontology matching" - the exploration of algorithmic approaches for automatically translating or aligning ontologies. These approaches, which exploit the explicit semantic properties of individual concepts, have registered impressive precision and recall results against humanly-engineered translations. However they are unable to make use of background cultural information about the overall systems in which those concepts are housed - how those systems are used, for what purpose they were designed, what methodological or theoretical principles underlined their construction, and so on. The present study investigates whether paying attention to these sociological dimensions of electronic knowledge systems could supplement algorithmic approaches in some circumstances. Specifically, it asks whether a holistic notion of commensurability can be useful when aligning or translating between such systems.      The first half of the study introduces the problem, surveys the literature, and outlines the general approach. It then proposes both a theoretical foundation and a practical framework for assessing commensurability of ontologies and other knowledge systems. Chapter 1 outlines the Semantic Web, ontologies and the problem of conceptual translation, and poses the key research questions. Conceptual translation can be treated as, by turns, a social, philosophical, linguistic or technological problem; Chapter 2 surveys a correspondingly wide range of literature and approaches.      The methods employed by the study are described in Chapter 3. Chapter 4 critically examines theories of conceptual schemes and commensurability, while Chapter 5 describes the framework itself, comprising a series of specific dimensions, a broad methodological approach, and a means for generating both qualitative and quantitative assessments. The second half of the study then explores the notion of commensurability through several empirical frames. Chapters 6 to 8 applies the framework to a series of case studies. Chapter 6 presents a brief history of knowledge systems, and compares two of these systems - relational databases and Semantic Web ontologies. Chapter 7, in turn, compares several "upper-level" ontologies - reusable schematisations of abstract concepts like Time and Space . Chapter 8 reviews a recent, widely publicised controversy over the standardisation of document formats. This analysis in particular shows how the opaque dry world of technical specifications can reveal the complex network of social dynamics, interests and beliefs which coordinate and motivate them. Collectively, these studies demonstrate the framework is useful in making evident assumptions which motivate the design of different knowledge systems, and further, in assessing the commensurability of those systems. Chapter 9 then presents a further empirical study; here, the framework is implemented as a software system, and pilot tested among a small cohort of researchers. Finally, Chapter 10 summarises the argumentative trajectory of the study as a whole - that, broadly, an elaborated notion of commensurability can tease out important and salient features of translation inscrutable to purely algorithmic methods - and suggests some possibilities for further work

Modeling assembly program with constraints. A contribution to WCET problem

Dissertação para obtenção do Grau de Mestre em Lógica ComputacionalModel checking with program slicing has been successfully applied to compute Worst Case Execution Time (WCET) of a program running in a given hardware. This method lacks path feasibility analysis and suffers from the following problems: The model checker (MC) explores exponential number of program paths irrespective of their feasibility. This limits the scalability of this method to multiple path programs. And the witness trace returned by the MC corresponding to WCET may not be feasible (executable). This may result in a solution which is not tight i.e., it overestimates the actual WCET. This thesis complements the above method with path feasibility analysis and addresses these problems. To achieve this: we first validate the witness trace returned by the MC and generate test data if it is executable. For this we generate constraints over a trace and solve a constraint satisfaction problem. Experiment shows that 33% of these traces (obtained while computing WCET on standard WCET benchmark programs) are infeasible. Second, we use constraint solving technique to compute approximate WCET solely based on the program (without taking into account the hardware characteristics), and suggest some feasible and probable worst case paths which can produce WCET. Each of these paths forms an input to the MC. The more precise WCET then can be computed on these paths using the above method. The maximum of all these is the WCET. In addition this, we provide a mechanism to compute an upper bound of over approximation for WCET computed using model checking method. This effort of combining constraint solving technique with model checking takes advantages of their strengths and makes WCET computation scalable and amenable to hardware changes. We use our technique to compute WCET on standard benchmark programs from M¨alardalen University and compare our results with results from model checking method

2019-2020, University of Memphis bulletin

University of Memphis bulletin containing the graduate catalog for 2019-2020.https://digitalcommons.memphis.edu/speccoll-ua-pub-bulletins/1439/thumbnail.jp

2018-2019, University of Memphis bulletin

University of Memphis bulletin containing the graduate catalog for 2018-2019.https://digitalcommons.memphis.edu/speccoll-ua-pub-bulletins/1438/thumbnail.jp

Management of Knowledge Representation Standards Activities

This report describes the efforts undertaken over the last two years to identify the issues underlying the current difficulties in sharing and reuse, and a community wide initiative to overcome them. First, we discuss four bottlenecks to sharing and reuse, present a vision of a future in which these bottlenecks have been ameliorated, and describe the efforts of the initiative's four working groups to address these bottlenecks. We then address the supporting technology and infrastructure that is critical to enabling the vision of the future. Finally, we consider topics of longer-range interest by reviewing some of the research issues raised by our vision

Semantically-enriched business process modeling and management

Business Process Modeling is a means to intuitively describe the enterprise\u27s organizational structure and interrelated business processes with the help of diagrams that are composed of Business Objects and that are stored in a dedicated database, the Business Object Repository. A large set of Business Objects that occur in the process models is labeled in natural language expressions. These object labels are neither checked in terms of language competence nor in terms of their business performance. This dissertation describes innovative solutions which cover the topics that are not exhaustively handled like the verification on language level as well as the better alignment between modeling levels and implementation levels. The solution creates and employs a knowledge matrix that adds a machine processable semantic layer on top of the Business Repository.Die Geschäftsprozessmodellierung ist eine Methode um intuitiv die Organisationsstrukturen und die abhängigen Geschäftsprozesse mit Hilfe von Modellen zu beschreiben. Die Modelle bestehen aus Geschäftsobjekten und werden in einer dedizierten Datenbank abgelegt, dem Business Repository. Ein großer Teil der Geschäftsobjekte sind mit natürlich sprachlichen Ausdrücken benannt. Die neuen Aufgabenstellungen sind die Prüfungen aller vorliegenden sprachabhängigen Arbeitsergebnisse von BPM auf Sprachkompetenz und auf Geschäftsperformanz. Die vorliegende Dissertation enthält innovative Lösungen zu bisher nicht vollständig behandelten Aufgabenstellungen wie der Verifizierung der Sprachebenen sowie einem besseren Alignment zwischen Modellierungsebenen und Umsetzungsebenen. Sie lässt eine Wissensmatrix entstehen, die dem klassischen BPM eine automatisierte, maschinenverarbeitbare neue Schicht - die semantische Ebene - oberhalb des Business Repository hinzufügt

2020-2021, University of Memphis bulletin

University of Memphis bulletin containing the graduate catalog for 2020-2021.https://digitalcommons.memphis.edu/speccoll-ua-pub-bulletins/1440/thumbnail.jp

2021-2022, University of Memphis bulletin

University of Memphis bulletin containing the graduate catalog for 2021-2022.https://digitalcommons.memphis.edu/speccoll-ua-pub-bulletins/1441/thumbnail.jp