The study of frameworks and formalisms for reasoning about action and change [67, 58, 61, 65, 70, 3, 57] has been central to the knowledge representation field almost from the inception of Artificial Intelligence as a general field of research [52, 56]. The phrase “Temporal Action Logics” represents a class of logics for reasoning about action and change that evolved from Sandewall’s book on Fe...

Solvation effects play a profound role in the energetics of protein folding. While a continuum dielectric model of solvation may provide a sufficiently accurate estimate of the solvation effects, until now this model was too computationally expensive and unstable for folding simulations. Here we proposed a fast yet accurate and robust implementation of the boundary element solution of the Poiss...

Typically agents have obligations of diiering importance. Consequently we give a hierarchical deenition of obligations, according to which an agent's obligations form a coherent hierarchy and new obligations are de-ned with reference to it. We then show how preferential entailment can be used to formalise the persistence and revision of obligation hierarchies.

Mechanical systems, of the kinds which are of interest for qualitative reasoning, are characterized by a set of real-valued parameters, each of which is a piecewise continuous function of real-valued time. A temporal logic is introduced which allows the description of parameters, both in their continuous intervals and around their breakpoints, and which also allows the description of actions be...

Modelling the beliefs of an agent who lacks logical omniscience has been a major concern recently. While most of the work has concentrated on propositional logics of belief, this paper primarily addresses issues raised by adding quantifiers to such logics. In particular, we are focusing on quantifying in and the distinction between "knowing what" and "knowing that". After arguing why a model of...

In this paper we introduce and formalise dynamic goal hierarchies. We begin with a formal definition of goals, according to which they are rational desires. In particular, we require that an agent’s goals are coherent; that is, that the agent believes that each goal is jointly realisable with all of the goals which the agent considers to be more important. Thus an agent’s goals form a hierarchy...

This memo presents current research in our laboratory. We address the following research topics: 1. Semantics-based assessment of nonmonotonic entailment methods for actions and change. 2. Implementation techniques for nonmonotonic entailment methods. 3. Algorithmic methods for planning and temporal reasoning. 4. Hybrid modelling of physical systems. 5. Design methodology for intelligent autono...

Ž . The electronic excited-state solvation dynamics of coumarin 314 C314 adsorbed at the airrwater interface was Ž . investigated by femtosecond time-resolved surface second-harmonic generation TRSHG . This Letter presents the first use of TRSHG to measure solvation dynamics and presents the theoretical basis for monitoring electronic excited-state solvation with TRSHG. The interfacial electron...