Ren(c)e Elio
Department of Computing Science
University of Alberta







Current Research My current research ranges from agent communication to computational models of human cognition. My past work has included empirical and theoretical analyses of human belief revision, non-monotonic reasoning, expert systems, and machine learning. I bring to these studies a strong interdisciplinary perspective that unites elements of artificial intelligence, philosophy, and  cognitive psychology. Common Sense, Reasoning, and Rationality explores themes of rationality for both humans and machines, from these interdisciplinary views.

Agent Communication for Cooperative Action This research project is concerned with the design and implementation of models for normative agent communication, from which error conditions for agent communication can be defined—cases in which an agent generates a not-understood or error message. Such a model specifies task and agent interdependencies, agent roles, and predicate properties at a domain-independent level of abstraction. The theoretical perspective taken here is that communication acts are actions upon a state, and that agent state is usefully modeled as consisting of beliefs, desires, and intentions. In the case of agent communication, the state is the internal state of the receiving agent.  The normative communication model defines what are legal actions upon specific elements of this state, and hence define which agent ‘beliefs’ are allowed to be updated, revised, or accessed via a communication act. The interaction model can also set policies for belief revision as a response to a not-understood message, which may be necessary when task allocation or coordination relationships change during run time.  Recent research work has extended and applied this framework to the web services domain.

Cognitive architectures, deliberation, and action The term belief-desire-intention (BDI) has been used to denote a position on theoretically useful mental state distinctions, particular models of how these mental states affect reasoning, and a genre of architectures or frameworks for developing software agents. Beyond the software agent community, elements of this BDI perspective receive a distinctly different realization in computational theories of human cognition. My interest in this area considers whether and how a general cognitive architecture achieves the functionality attributed to a BDI model of agency, particularly in matters related to deliberation, goal formation, goal values, and the meta-level choice between deliberation and action. Finding the same themes of rational agency emerging at architectures specified at different levels of abstraction reinforces the intuitions driving these theories and provides new insights into how these intuitions translate into process models of cognition. Students with a strong background and interest in cognitive science should contact me about possible work in this area and are encouraged to explore the ACT-R architecture.

Belief Revision When a reasoner recognizes that some newly-acquired information causes a conflict with a set of currently-held beliefs, there may be different ways of resolving that conflict, and these different ways correspond to abandoning (or at least calling into question) different ones of the currently-held beliefs. One issue that arises under this characterization concerns the principles by which such a decision is made, i.e., the decision to abandon belief i rather than belief j, so that the new information can be incorporated into a consistent situational model. Belief revision is a crucial part of everyday reasoning, scientific reasoning, and even agent communication. My objective in this line of work is to understand how relevant knowledge is brought to bear in constructing alternative accounts or belief sets; There are various metrics to choosing among alternative belief sets once they are constructed. It is the controlled construction of these states that is most interesting to me, for without specifying the process of belief state construction and how it stops, a reasoner will be forever mired in deliberation. Hence, belief revision is strongly related to control issues for intention setting and re-deliberation.

Previous Research Areas My previous work has included experimental and systems work related to belief revision, case based learning, inductive reasoning, and other issues in cognitive science. I was also a principal investigator on the Orlando Project