Mechanisms for answering 'why not' questions in rule- and object-based systems

One type of question that has largely been avoided in explanation facilities for expert systems is the negative, “Why not” type of question. This question asks the intelligent system why a user-anticipated conclusion was not realized by the system.; There have been some systems that have dealt with this type of question, but the knowledge representations in these systems are limited. The mechanisms developed for this dissertation are an attempt to overcome the limitations of these past systems at least in part by furnishing tools that assist in more cooperative answers to “Why not” types of questions for systems whose conditions and actions are both more complex (utilizing more complex objects and continuously varying values) and more general (utilizing variables). The mechanisms developed were implemented in a problem-practice system for entity relationship diagrams for database management systems. An initial protocol analysis of user interaction with the developed system was performed to provide a preliminary qualitative look at how users interact with the facilities provided and to collect their comments about the environment. Results of the analyses were somewhat mixed but were promising, and the observations and comments provide insight into future development directions for the system.