Plan recognition, activity recognition, and intent recognition all involve making inferences about other actors from observations of their behavior, i.e., their interaction with the environment and with each other. The observed actors may be software agents, robots, or humans. This synergistic area of research combines and unifies techniques from user modeling, machine vision, intelligent user interfaces, human/computer interaction, autonomous and multi-agent systems, natural language understanding, and machine learning. It plays a crucial role in a wide variety of applications including:

* assistive technology
* software assistants
* computer and network security
* behavior recognition
* coordination in robots and software agents
* e-commerce and collaborative filtering

This diversity of applications and disciplines, while producing a wealth of ideas and results, has contributed to fragmentation in the field, as researchers publish relevant results in a wide spectrum of journals and conferences.

This workshop seeks to bring together researchers and practitioners from diverse backgrounds, to share in ideas and recent results. It aims to identify important research directions and opportunities for synthesis and unification. Contributions are sought in the following areas of research:

* Plan, activity, intent, or behavior recognition
* Adversarial planning, opponent modeling
* Modeling multiple agents, modeling teams
* User modeling on the web and in intelligent user interfaces
* Acquaintance models
* Plan recognition and user modeling in marketplaces and e-commerce
* Intelligent tutoring systems (ITS)
* Machine learning for plan recognition and user modeling
* Personal software assistants
* Social network learning and analysis
* Monitoring agent conversations (overhearing)
* Observation-based coordination and collaboration (teamwork)
* Multi-agent plan recognition
* Observation-based failure detection
* Monitoring multi-agent interactions
* Uncertainty reasoning for plan recognition
* Commercial applications of user modeling and plan recognition
* Representations for agent modeling
* Modeling social interactions
* Inferring emotional states
* Reverse engineering and program recognition
* Programming by demonstration
* Imitation

Due to the diversity of disciplines engaging in this area, related contributions in other fields, are also welcome.