Multimodal Reasoning about Physical Systems

Abstract We present a knowledge representation and reasoning framework that integrates qualitative reasoning, qualitative simulation, numerical simulation, geometric reasoning, constraint reasoning, resolution, reasoning with abstraction levels, declarative meta-level control, and a simple form of truth maintenance. The framework is the core of PRET, a system identification program that automates the process of modeling physical systems. Introduction Models are powerful tools that are used to understand physical systems. The process of inferring an internal model from external observations of a system---often called system identification--is a routine and difficult problem faced by engineers in a variety of domains The program PaET (Bradley & Stolle 1996) automates both stages of the system identification process; its goal is to find a system of ODEs that models

Is There Any Need for Domain-Dependent Control Information? A Reply

In this paper, we consider the role that domaindependent control knowledge plays in problem solving systems. Ginsberg and Geddis (Ginsberg & Geddis 1991) have claimed that domaindependent control information has no place in declarative systems; instead, they say, such information should be derived from declarative facts about the domain plus domain-independent principles. We dispute their conclusion, arguing that it is impractical to generate control knowledge solely on the basis of logical derivations. We propose that simplifying abstractions are crucial for deriving control knowledge, and, as a result, empirical utility evaluation of the resulting rules will frequently be necessary to validate the utility of derived control knowledge. We illustrate our arguments with examples from two implemented systems. Introduction In a AAAI paper entitled "Is there any Need for Domain-Dependent Control Information?" Ginsberg and Geddis (1991) (henceforth G&G) consider whether domain-dependent c..

A microworld model for multiagent computer-aided process planning.

This Thesis proposes and investigates a novel framework for the study of multiagent solutions for computer-aided process planning (CAPP) in manufacturing systems. The framework is based on a domain-specific microworld model of CAPP, called the CAPP World. The motivation comes from the current literature on multiagent systems (MAS) for CAPP, which emphasized the need for comparative studies that would identify the most suitable domain-specific multiagent solutions, and from the observation that a simple, manageable framework for such studies had not been developed. The proposed CAPP World is characterized by a product class, a model of a manufacturing cell, and appropriate adaptation and simplification of CAPP modeling concepts from the literature. These abstractions lead to a collection of specific actions that jointly construct a process plan in CAPP World. The analysis shows that the model meets its design objectives of being: simple integral in the sense of including the main aspects of CAPP representative of properties and difficulties in real-world CAPP and suitable for formulation and investigation of MAS solutions for CAPP. The suitability of CAPP World for domain-specific MAS studies is demonstrated through construction of concrete scenarios addressing topics such as: agent encapsulation, cooperation and coordination among team members, cooperative iterative improvements of process plan, improving the efficiency of process planning through caching of design solutions, team composition, and communication mechanisms. The Thesis also identifies some topics for future research. --P.[i]The original print copy of this thesis may be available here: http://wizard.unbc.ca/record=b164402