We present the PHATT algorithm for plan recognition. Unlike previous approaches to plan recognition, PHATT is based on a model of plan execution. We show that this clarifies several difficult issues in plan recognition including the execution of multiple interleaved root goals, partially ordered plans, and failing to observe actions. We present the PHATT algorithm’s theoretical basis, and an im...

Madsen, Sarah; Evans, Diane; Hamer, Thomas; Henson, Paul; Miller, Sherri; Nelson, S. Kim; Roby, Daniel; Stapanian, Martin. 1999. Marbled murrelet effectiveness monitoring plan for the Northwest Forest Plan. Gen. Tech. Rep. PNW-GTR-439. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 51 p. This report describes options for effectiveness monitorin...

ion and Indexing Although the intermediate states are very helpful when recognizing plans with incomplete plan libraries, the statespace for a given planning domain may be quite large (Kerkez and Cox, 2001). A large number of possible situations negatively affect the retrieval efficiency of the recognizer. We developed an indexing and retrieval scheme based on the concept of state abstraction t...

introduction: breast conserving radiotherapy is one of the most common procedures performed in any radiation oncology department. a tangential parallel-opposed pair is usually used for this purpose. this technique is performed using 2d or 3d treatment planning systems. the aim of this study was to compare 2d treatment planning with 3d treatment planning in tangential irradiation in breast conse...

The ability of a planner to reuse parts of old plans is hypothesized to be a valuable tool for improving eeciency of planning by avoiding the repetition of the same planning eeort. We test this hypothesis from an analytical and empirical point of view. A comparative worst-case complexity analysis of generation and reuse under diierent assumptions reveals that it is not possible to achieve a pro...

While most plan recognition systems make use of a plan library that contains the set of available plan hypotheses, little effort has been devoted to the question of how to create such a library. This problem is particularly difficult to deal with when only little domain knowledge is available—a common situation when e.g. developing a help system for an already existing software system. This pap...

Intelligent agents are often called upon to form plans that direct their own or other agents' activities. For these systems, the ability to describe plans to people in natural ways is an essential aspect of their interface. In this paper, we present the Cooperative Plan Identi cation (CPI) architecture, a computational model that generates concise, e ective textual descriptions of plan data str...

Terminological Plan Recognition Diane Litman, AT&T Bell Laboratories, USA Description logics are widely used in AI to construct concept taxonomies based on subsumption inferences. However, current description logics are unable to handle complex compositions of concepts, for example constraint networks where each node is described by an associated concept. Plans can be thought of as constraint n...

A significant amount of prior research effort in the field of Artificial Intelligence has gone into the design and analysis of planning algorithms. For the most part, this work has been guided by several strong, simplifying assumptions, most notably, that the plans will be performed in static, deterministic environments. Although these assumptions have made rigorous formal analysis possible, th...