title: Effective Intentions: Reasoning Effectively with the Effects of Behaviours in International Agents
Creators: name: Cleaver, Timothy William
Publisher: name: Griffith University
Year: 2010
Subjects: subject: AgentSpeak agent-oriented programming language
subject: Practical reasoning
subject: Causal knowledge

description: Practical reasoning encapsulates all thought towards behaviour and action. Central to this lies the relationship between decisions towards behaviour and the establishment of the optimal commitment towards the outcomes of these decisions. A core element in these decisions are the eects actions and behaviours cause. Traditionally, study of causation has not been undertaken from the wider perspective of practical reasoning and bounded rationality. It is fromthis broader view that this thesis progresses. Given agents with commitments towards ongoing behaviours in complex and dynamic environments, roles that causal knowledge pertaining to these commitments play in thewider practical reasoning of such agents are investigated. ree such roles are identi‚ed. e utilization of behavioural knowledge in the maintenance of the validity and the recognition of the success or failure of behaviour is studied. In particular, mechanisms for the resolution of con…icting evidence for the success or failure of behaviours are evaluated. e trade-o between optimal reasoning and optimal behaviour towards monitoring for such evidence is then examined. e role of such behavioural knowledge in the revision of an agent’s beliefs is then investigated. It is argued that the eect of such belief revisions on the commitments held is a more crucial metric in determining optimal revisions than the informational content retained by the options under consideration. e rationality of such revisions fromthe traditional belief dynamics perspective is then established. Causal knowledge is then utilized in the consistency maintenance of the commitments an agent makes. is consistency maintenance leads to dependencies between the commitments held. ese dependencies are then used to construct techniques for both the quanti‚cation of the commitment an agent places in a given intention and mechanisms for the rational propagation of intention revision. is thesismakes numerous contributions subsequent to the investigations detailed above. A model of actions, eects and maintenance conditions is formalized. e syntax of the AgentSpeak agent-oriented programming language is then extended to integrate an equivalent representation. emeaning of this additional syntax is then made clear by a corresponding extension to the semantics of the AgentSpeak language. is extension is concerned with the maintenance of the validity of the behaviours under execution and the recognition of their success or failure. It is done in such a way as to facilitate customizable con…ict resolution mechanisms and monitoring strategies. c e aforementioned formalmodel of action, validity and eects lies at the heart of a number of new belief revision operators. ese operators are de‚ned in a similar style to those of traditional belief revision and their rationality is proved within the AGM framework. It is shown that the operators proposed both maximize the bene‚cial eect on the agent’s commitments while also being rational revisions from the belief dynamics perspective. By maintaining the consistency of the behaviours adopted by way of their outcome conditions, dependencies between intentions arise. A formal theory of commitment is developed based on these dependencies. Central to this formal theory is the intuition that the commitment an agent should hold in a given intention is proportional to the cost of dropping or revising it. is theory is then utilized to develop a number of intention revision propagation strategies. ese strategies balance the need for stability against optimality. It is then demonstrated how this theory can be extended to capture the additional relationships between intentions inherent in the AgentSpeak model.