Ontologies are widely used as data representations for knowledge bases and marking up data on the emerging Semantic Web. Hence, techniques for managing ontol- ogy come to the centre of any practical and general solution of knowledge-based systems. Challenges arise when we look a step further in order to achieve flexibility and scalability of the ontology management. Previous works in ontology management, primarily for ontology mapping, ontology integration and ontology evolution, have exploited only one form or another of ontology management in restrictive settings. However, a distributed and heterogeneous environment makes it necessary for re- searchers in this field to consider ontology interoperability in order to achieve the vision of the Semantic Web. Several challenges arise when we set our goal to achieve ontology interoperability on the Web. The first one is to decide which soft- ware engineering paradigm to employ. The issue of such a paradigm is the core of ontology management when dynamic property is involved. It should make it easy to model complex systems and significantly improve current practice in software engineering. Moreover, it allows the extension of the range of applications that can feasibly be tackled. The second challenge is to exploit frameworks based on the pro- posed paradigm. Such a framework should make possible flexibility, interactivity, reusability and reliability for systems which are built on it. The third challenge is to investigate suitable mechanisms to cope with ontology mapping, integration and evolution based on the framework. It is known that predefined rules or hypotheses may not apply given that the environment hosting an ontology is changing over time. Fortunately, agents are being advocated as a next generation model for en- gineering complex and distributed systems. Also some researchers in this field have given a qualitative analysis to provide a justification for precisely why the agent-based approach is well suited to engineer complex software systems. From a multi-agent perspective, agent technology fits well in developing applications in uncontrolled and distributed environments which require substantial support for change. Agents in multi-agent systems (MAS) are autonomous and can engage in interactions which are essential for any ongoing agents� actions. A MAS approach is thus regarded as an intuitive and suitable way of modelling dynamic systems. Following the above discussion, an agent-based framework for managing ontology in a dynamic environment is developed. The framework has several key characteris- tics such as flexibility and extensibility that differentiate this research from others. Three important issues of the ontology management are also investigated. It is be- lieved that inter-ontology processes like ontology mapping with logical semantics are foundations of ontology-based applications. Hence, firstly, ontology mapping is discussed. Several types of semantic relations are proposed. Following these, the mapping mechanisms are developed. Secondly, based on the previous mapping results, ontology integration is developed to provide abstract views for participating organisations in the presence of a variety of ontologies. Thirdly, as an ontology is subject to evolution in its life cycle, there must be some kind of mechanisms to reflect their changes in corresponding interrelated ontologies. Ontology refinement is investigated to take ontology evolution into consideration. Process algebra is employed to catch and model information exchanges between ontologies. Agent negotiation strategy is applied to guide corresponding ontologies to react properly. A prototype is built to demonstrate the above design and functionalities. It is applied to ontologies dealing with the subject of beer (type). This prototype con- sists of four major types of agents, ranging from user agent, interface agent, ontology agent, and functionary agent. Evaluations such as query, consistency checking are conducted on the prototype. This shows that the framework is not only flexible but also completely workable. All agents derived from the framework exhibit their behaviours appropriately as expected.

A resurgence of interest in ontology emerged in the 1990s from the field of information systems engineering. From beginnings such as the Cyc project to codify commonsense knowledge and the Stanford Knowledge Sharing Laboratory efforts to build a shareable ontology of terms, emerged a multitude of ontologies, academic contributions, conferences and commercial companies. / However, does "applied ontology", as a joint field between information systems engineering and philosophy, actually exist? A field that equally informs both engineering and philosophical ontology has obstacles to overcome. For example, according to Grüber's (1993) ubiquitous definition, engineering ontology is a "specification of a conceptualization", whereas in philosophy an ontology is "a systematic account of Existence" - a significant difference. Furthermore, there are philosophical objections to ontology that may undermine its practical application. In this dissertation, we aim to overcome these obstacles by approaching engineering requirements analysis through a particularist metaphysics. More specifically, we argue that engineering 'requirements analysis' can be approached through the ontological question "what exists when the requirements are satisfied?" This approach to requirements analysis forms the core of a joint engineering and philosophical ontology. / The argument obligates us to demonstrate an example of the ontological approach to requirements analysis. We select 'Competitive Intelligence' (CI) as a commercial practice where engineering requirements lend themselves to ontological analysis. A working definition for CI emerges as being "the integration of piecemeal information to support organisational strategy". The major part of the dissertation is a formal analysis (using logic programs) that demonstrates a modified version of this definition can be coherently expressed and used to show the existence of CI as such. The logic also shows CI, as defined, supervenes on other information systems, and depends mainly on a strategic framework. / As such, for the research at hand, the analysis suffices as foundation of an ontology of CI, demonstrates the use of ontology as a requirements analysis approach, and develops a practice of applied ontology that equally informs engineering and philosophy.

As information systems become more complex it is infeasible for a non-expert to understand how the information system has evolved. Accurate models of these systems and the changes occurring to them are required for interpreters to understand, reason over, and learn from evolution of these systems. Ontologies purport to model the semantics of the domain encapsulated in the system. Existing approaches to using ontologies do not capture the rationale for change but instead focus on the direct differences between one version of a model and the subsequent version. Some changes to ontologies are caused by a larger context or goal that is temporally separated from each specific change to the ontology. Current approaches to supporting change in ontologies are insufficient for reasoning over changes and allow changes that lead to inconsistent ontologies. / In this thesis we examine the existing approaches and their limitations and present a four-level classification system for models representing change. We address the shortcomings in current techniques by introducing a new approach, augmenting ontologies with operations for capturing and representing change. In this approach changes are represented as a series of connected, related and non-sequential smaller changes. The new approach improves on existing approaches by capturing root causes of change, by representing causal relationships between changes linking temporally disconnected changes to a root cause and by preventing inconsistencies in the evolution of the ontology. The new approach also explicitly links changes in an ontology to the motivating real-world changes. We present an abstract machine that defines the execution of operations on ontologies. A case study is then used to explain the new approach and to demonstrate how it improves on existing ways of supporting change in ontologies. The new approach is an important step towards providing ontologies with the capacity to go beyond representing an aspect of a domain to include ways in which that representation can change.

<p>Due to the explosion of the amount of biomedical data, knowledge and tools that are often publicly available over the Web, a number of difficulties are experienced by biomedical researchers. For instance, it is difficult to find, retrieve and integrate information that is relevant to their research tasks. Ontologies and the vision of a Semantic Web for life sciences alleviate these difficulties. In recent years many biomedical ontologies have been developed and many of these ontologies contain overlapping information. To be able to use multiple ontologies they have to be aligned or merged. A number of systems have been developed for aligning and merging ontologies and various alignment strategies are used in these systems. However, there are no general methods to support building such tools, and there exist very few evaluations of these strategies. In this thesis we give an overview of the existing systems. We propose a general framework for aligning and merging ontologies. Most existing systems can be seen as instantiations of this framework. Further, we develop SAMBO (System for Aligning and Merging Biomedical Ontologies) according to this framework. We implement different alignment strategies and their combinations, and evaluate them in terms of quality and processing time within SAMBO. We also compare SAMBO with two other systems. The work in this thesis is a first step towards a general framework that can be used for comparative evaluations of alignment strategies and their combinations.</p> / Report code: LiU-Tek-Lic-2006:6.

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. / Singapore-MIT Alliance (SMA)

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. / Singapore-MIT Alliance (SMA)

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. / Singapore-MIT Alliance (SMA)

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. / Singapore-MIT Alliance (SMA)

This dissertation examines the possible interchangeable connection between the medieval ontological relationship of essence/existence and the modern epistemological relationship of subject/object. Rather than investigating the many medieval and modern philosophers, this dissertation focuses on two philosophers as study cases: One is the Islamic philosopher Mulla Sadra, and the other is the German philosopher George. W. F. Hegel. While the medieval relationship of essence/existence finds its highest development in Sadra, the modern relationship of subject/object finds its highest summit in Hegel. Sadra's break with the metaphysical essentialism of both Greek philosophy and Arabic philosophy results in the moment of Absolute Existentialism. This moment is not explicitly mentioned by Hegel-- neither in the historical development of the Philosophical Idea in the Lectures on The History of Philosophy, nor in the conceptual development of the Logical Idea in the Science of Logic. If the moment of the Absolute Existentialism is contained within Hegel's Absolute Idealism at all, it is so implicitly, as a moment within the Hegelian Idea's self-dialectical process of determining. In this dissertation, I unveil Sadra's moment of the Absolute Existentialism within Hegel's moment of the Absolute Idealism. I argue that, although Sadra's Absolute Existentialism and Hegel's Absolute Idealism are different, both challenge the traditional views of metaphysical essentialism. I provide the logical connection between Sadra's and Hegel's critiques of metaphysical essentialism. I show that, within Hegel's Absolute Idealism, Sadra's Absolute Existentialism emerges in opposition to quality as affirmative reality in the metaphysical essentialism of the Aristotelian tradition. / McAnulty College and Graduate School of Liberal Arts; / Philosophy / PhD; / Dissertation;

While remaining rooted in a comparison of some of the primary texts of the thinkers under scrutiny, my thesis also discusses several issues which arise in the mutual consideration of Heidegger and Strauss, specifically the questions of the ontological and political status of nature, the problem of ‘first philosophy,’ and the method by which to interpret philosophical texts, as well as a continuous analysis of Strauss’s appellation of ‘modern,’ as opposed to ‘ancient,’ and ‘religious,’ as opposed to ‘philosophical,’ to Heidegger’s thought. I first consider every moment in Strauss’s corpus where he discusses Heidegger’s thought. From this discussion, I identify four main lines of critique which may be extracted from Strauss’s writings on Heidegger. Then, I turn to Heidegger’s texts themselves in order to determine if Strauss’s critique indeed finds purchase there, addressing each of the lines of critique in turn. Finally, I consider Strauss and Heidegger in tandem, in light of the three questions identified above. I show that many of what Strauss determines to be Heidegger’s errors arose as a result of the way that Heidegger read ancient philosophical texts, and I suggest that Strauss’s approach, i.e., to consider the possible esoteric meaning of a text, in fact permits the reader to access an interpretation that is truer to the textual phenomena. This claim, however, is not intended to obscure the remarkable similarities between each thinker’s respective interpretive methods. I conclude that Strauss’s critique of Heidegger, vehement as it is, also indicates Strauss’s dependence on Heidegger’s thought for the inspiration of Strauss’s own philosophical project. The relation between Strauss and Heidegger, then, remains profoundly ambiguous.