We propose a methodology to automatically generate plans for a robot excavator like a bucket loader or a backhoe. The task is formulated as one of constrained optimization in an action space that is spanned by the parameters of a prototypical digging plan. We show how geometric and force constraints are imposed on the action space to build the set of feasible plans, and discuss methods to optim...

In this paper we present an algorithm for planning in nondeterministic domains. Our algorithm C-SHOP extends the successful classical HTN planner SHOP, by introducing new mechanisms to handle situations where there is incomplete and uncertain information about the state of the environment. Being an HTN planner, C-SHOP supports coding domain-dependent knowledge in a powerful way that describes h...

This study used 3T MRI to elucidate the functional role of supplementary motor area (SMA) in relation to visuo-spatial processing. A localizer task contrasting sequential number subtraction and repetitive button pressing was used to functionally delineate non-motor sequence processing in pre-SMA, and activity in SMA-proper associated with motor sequencing. Patterns of BOLD responses in these re...

In many robotic industrial applications, a manipulator should move among obstacles and reach a set of task-points in order to perform a pre-defined task. It is quite important as well as very complicated to determine the time-optimum sequence of the task-points visited by the end-effector's tip only once assuring that the manipulator's motion through the successive task-points is collision-free...

We recently showed how counterexample-guided abstraction refinement can be used to derive informative heuristics for optimal classical planning. In this work we introduce an algorithm for building additive abstractions and demonstrate that they outperform other state-of-the-art abstraction heuristics on many benchmark domains. Introduction Recently, we presented a new algorithm for deriving adm...

Deformations that occur between pre-operative scans and the intra-operative setup can render pre-operative plans inaccurate or even unusable. It is therefore important to predict such deformations and account for them in pre-operative planning. This paper examines two different, yet related methodologies for this task, both of which collect statistical information from a training set in order t...

This study examines the effects of age, cognitive resources, and task familiarity on planning performance. Fifty-two young and 52 old adults completed one of two errand-planning tasks. The tasks were matched for structure, difficulty, and format, but differed in content, such that one planning task required planning a real-world shopping tour whereas the other involved planning an unfamiliar sp...

The smooth transitions between turns in natural conversation suggest that speakers often begin to plan their utterances while listening to their interlocutor. The presented study investigates whether this is indeed the case and, if so, when utterance planning begins. Two hypotheses were contrasted: that speakers begin to plan their turn as soon as possible (in our experiments less than a second...