Interaction with users is a key capability of planning systems that are applied in real-world settings. Such a system has to be able to react appropriately to requests issued by its users. Most of these systems are based on a generated plan that is continually criticised by him, resulting in a mixed-initiative planning system. We present several practically relevant requests to change a plan in...

Classical planning is the problem of synthesizing a sequence of actions to reach the goal state starting from the initial state. Hierarchical task networks (HTNs) have been used as a guidance for solving planning problems where tasks are decomposed into subtasks. Recently, both action-based planning as well as HTNbased planning have been east as SAT. The performance of planning as SAT has been ...

This paper describes a collaboration between two PhD students. The first author is developing a course generator (CG) for a Web-based e-learning environments (WBLE) [3]. A CG generates sequences of learning objects according to the learner’s goals and individual properties. The assembling process is knowledge intensive: assembling courses that implement modern pedagogical theories requires a fr...

Considerable work has focused on enhancing the semantics of Hierarchical Task Networks (HTNs) in order to advance the state-of-the-art in hierarchical planning. For instance, the Hierarchical Goal Network (HGN) formalism operates over a hierarchy of goals to facilitate tighter integration of decompositional planning with classical planning. Another example is the Action Notation Markup Language...

Keeping planning problems as small as possible is a must in order to cope with complex tasks and environments. Earlier, we have described a method for cascading Description Logic (dl) representation and reasoning on the one hand, and Hierarchical Task Network (htn) action planning on the other. The planning domain description as well as the fundamental htn planning concepts are represented in d...

In this paper we explore the use of Hierarchical-Task-Network (HTN) representations to model strategic game AI. We will present two case studies. The first one reports on an experiment using HTNs to model strategies for Unreal Tournament® (UT) bots. We will argue that it is possible to encode strategies that coordinate teams of bots in first-person shooter games using HTNs. The second one compa...

Dynamic changes in complex, real-time environments, such as modern video games, can violate an agent’s expectations. We describe a system that responds competently to such violations by changing its own goals, using an algorithm based on a conceptual model for goal driven autonomy. We describe this model, clarify when such behavior is beneficial, and describe our system (which employs an HTN pl...

Constraint satisfaction problems provide strong formalism for modeling variety of real life problems. This paper presents a work currently in progress of which the goal is an application of the CSP formalism on hierarchical task network planning domain. An encoding of HTN planning problems as a dynamic CSP is presented. We suppose that such encoding would provide a way for search space reductio...

We focus on interactive comedy, a relatively new genre in interactive drama, in this study. To be able to maintain the story, we adopt hierarchical task network planning (HTN) for planning of a character agent. We then extend HTN such that the extended HTN allows for the direct use of character failures, higher interactions with the viewer, and more story variations. Our extensions lead to effe...

Adapting plans to changes in the environment by finding alternatives and taking advantage of opportunities is a common human behavior. The need for such behavior is often rooted in the uncertainty produced by our incomplete knowledge of the environment. While several existing planning approaches deal with such issues, artificial agents still lack the robustness that humans display in accomplish...