work contained in this document has been submitted in support of an application for a degree or qualification of this or any other university or other institution of learning. All verbatim extracts have been distinguished by quotation marks, and all sources of information have been specifically acknowledged. Signed: Date: January 2005 This thesis describes a model of norm-governed practical reasoning agents and demonstrates the implementation of this model in the form of the NoA Normative Agent language and architecture. The introduction of normative concepts such as obligations, permissions and prohibitions into the practical reasoning of an agent is motivated by the need for effective coordination mechanisms in open systems. These are typically “multi-vendor ” scenarios, where independently designed agents, as representatives of human organisations and individuals, form short to medium term coalitions and collaborate in the performance of specific tasks. Electronic commerce is one of the most prominent examples of such scenarios. The use of autonomous software agents provides the

Current collaborative work environments are characterized by dynamically changing organizational structures. Although there have been several efforts to refine work distribution, especially in workflow management, most literature assumes a static database approach which captures organizational roles, groups and hierarchies and implements a dynamic roles based agent assignment protocol. However, in practice only partial information may be available for organizational models, and in turn a large number of exceptions may emerge at the time of work assignment. In this paper we present an organizational model based on a policy based normative system. The model is based on a combination of an intensional logic of agency and a flexible, but computationally feasible, non-monotonic formalism (Defeasible Logic). Although this paper focuses on the model specification, the proposed approach to modelling agent societies provides a means of reasoning with partial and unpredictable information as is typical of organizational agents in workflow systems. 1

Abstract. This paper provides a computational framework, based on Defeasible Logic, to capture some aspects of institutional agency. Our background is Kanger-Lindahl-Pörn account of organised interaction, which describes this interaction within a multi-modal logical setting. This work focuses in particular on the notions of counts-as link and on those of attempt and of personal and direct action to realise states of affairs. We show how standard Defeasible Logic can be extended to represent these concepts: the resulting system preserves some basic properties commonly attributed to them. In addition, the framework enjoys nice computational properties, as it turns out that the extension of any theory can be computed in time linear to the size of the theory itself.

Abstract. Starting from a general definition of how to model the organisation of multiagent systems with the aid of holonic structures, we discuss design parameters for such structures. These design parameters can be used to model a wide range of different organisational types. The focus of this contribution is to link these design parameters with a taxonomy of different types of autonomy relevant in multiagent organisation. We also discuss the constraining effect of autonomy on the recursive nesting of multiagent organisation. As the domain for applying multiagent systems we choose a general view on multiagent task-assignment. 1

with love and gratitude Will it be possible to create a self-aware and reasoning entity that has the capacity for decision making similar to that we ascribe to human beings? Modern agent systems, although used today in various applications wherever intelligence is required, are not ready for applications where human rationalities are usually the only option in making important decisions in critical or sensitive situations. This thesis is a contribution to this area: a decision-making methodology is introduced to address the different characteristics that an agent should have in order to be better trusted with such critical decisions. The work begins with a study of philosophy in the literature (Chapter 2), which reveals that trust is based on emotions and faith in performance. The study concludes that a trustworthy decision has five main elements: it considers options and their likely effects; it predicts how the environment and other agents

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