Planning is an integral part of many behavioural aspects related to transportation: residential relocation, activity and travel scheduling, route choice, etc. People make plans and then select actions to execute those plans. The plans are inherently dynamic. They evolve due to situational constraints and contextual factors, experience, inertia, or changing preferences. As a result, the chosen a...

My research on algorithms applies to two general areas, mathematical biology and number theory. My switch to biological problems is recent. The broader impact of extracting information from biological sequences is great, despite the difficulty of precise problem definition. My graduate thesis develops a specialized number theory algorithm which converts a question about modular forms into a com...

Recognition of goals and plans using incomplete evidence from action execution can be done efficiently by using planning techniques. In many applications it is important to recognize goals and plans not only accurately, but also quickly. In this paper, we develop a heuristic approach for recognizing plans based on planning techniques that rely on ordering constraints to filter candidate goals f...

We discuss the application of model based diagnosis to (multi-)agent based planning. First, we model a plan as a system to be diagnosed, taking into account the behavioural relations that might exist between several instances of actions occurring in a plan. Then we consider the case of a spatially distributed agent planning system where different agents are responsible for a part of the total p...

Partially ordered plans have several useful properties, such as exhibiting the structure of the plan more clearly which facilitates post-plan generation tasks like scheduling the plan, explaining it to a user, or breaking it into subplans for distributed execution. The standard interpretation of partial ordering implies that whenever two subplans are unordered, every interleaving of steps from ...

The security architecture of the Plan 9" operating system has recently been redesigned to address some technical shortcomings. This redesign provided an opportunity also to make the system more conve­ nient to use securely. Plan 9 has thus improved in two ways not usually seen together: it has become more secure and easier to use. The central component of the new architecture is a per-user self...

This paper proposes that a comprehensive theory of stories must include components that deal with: (a) plan understanding, (b) narrative comprehension, and (c) the unique structural and affective aspects of the subclass of narratives that are stories.