• Corpus ID: 17678819

Heracles : Hierarchical Dynamic Constraint Networks for Interactive Planning

@inproceedings{AmbiteHeraclesH,
  title={Heracles : Hierarchical Dynamic Constraint Networks for Interactive Planning},
  author={J. Ambite and Craig A. Knoblock and Maria Muslea}
}

• J. Ambite, Craig A. Knoblock, Maria Muslea
• Computer Science

For any human activity there is a wealth of information available in the Internet and in corporate intranets. Unfortunately , such information is distributed among many sites, with different data formats, schemas, and semantics. Moreover , information access per se is of limited value. What is needed is a system that integrates and structures diverse information in support of the user tasks and goals. The system must focus on the relevant information, evaluate tradeoffs, and suggest courses of action to the user. In this demo, we we present Heracles, a constraint-based framework to easily develop such systems. As an example consider travel planning. There are numerous sites with relevant travel information: flight schedules and fares needs to be integrated with user preferences, such as preferred airlines or flying times (e.g. avoid red-eye flights), cost constraints, and company policies, such as allowable airlines, expenses caps, per-diem or mileage reimbursement rates. Although the user could visit these sites and take into accounts all the constraints and preferences, it is extremely tedious, error-prone, and time-consuming. A system that queries these the remote sites, access local information, and enforces the constraints and preferences is much more desirable. Heracles models each piece of information as a variable in a constraint network. The different pieces of information are integrated using constraints. The resulting constraint network provides a coherent view of the user activities and captures the relevant information and user preferences. For any non-trivial user activity the number of variables and constraints is very large. So we do not propose a monolythic constraint network, but we partition the network hierarchically. This hierarchy corresponds to the task structure of the application domain, in a manner similar to Hierarchical Task Network planning (Erol, Hendler, & Nau 1994). The application designer groups variables and constraint related to a distinct task into a package that we call a template. For example, in travel planning we would have a top-level template that contains the most important information, such as who is traveling, the dates of travel, and the origin and destination. The next layer of decisions include the alternative means of transportation, such as flying, taking a train, renting a car, driving the user's own car, or taking a taxi; and choices of accommodation at the destination. The variables and constraint related to flying would constitute a template. Task/Templates are further decomposed into smaller units. For example, once that the user …