Interactive configuration : a logic programming-based approach

Abstract

The key component of an interactive configurator is the constraint manager which is responsible for incrementally maintaining the relationship between choices and constraint violations. As the user makes or modifies choices, the constraint manager makes accessible the violated constraints and the relevant alternatives that the user may consider to move forward toward a solution. The requirement to deliver meaningful and timely feedback imposes significant demands on the flexibility, efficiency and explainability of constraint management.

Admitting a strong commitment to Logic Programming (LP) as a fundamental paradigm for developing configuration systems, this thesis contributes a LP-based representation for configuration knowledge which uniquely integrates support for object-oriented modeling, dynamic default inheritance, negation as inconsistency and a three-value logic. Additionally, it provides the design, implementation and evaluation of a novel constrain manager which admits performance trade-off flexibility in the delivery of constraint management in LP.

Knowledge-based configuration has been an active and important research area since the triumphs of the computer-system configurator known as XCON developed by John McDermott in 1982. Configuration systems rely heavily on the representation of parts and their associated connectivity. this knowledge is often conceptualized in terms of configuration compnents, their properties, and constraints that govern their inter-connectivity. Purely automate configurators search for valid configurations given initial parameters and a body of constraints. These systems ignore the user's tacit requirements; those requirements which are not well understood at the outset, and may be best realized as the user is interactively exposed to the effects of different constraints on key choices.

Interactive configuration is a view of the configuration task which includes the user as an essential component of a dynamic process. The interactive configurator is designed to assist the user in an interactive and incremental exploration of the configuration space. It may guide or advise the user's decision making but it must communicate requirements or inconsistencies effected by the constraints in response to the user's choices. this feedback helps the user to refine the configuration space toward a satisfying solution.