ABSTRACT
In this chapter, we give an example of CIRCSIM-Tutor in action,explain its software architecture, and give a brief description ofthe main components of the system. We then discuss some architectural issues and how the architecture has changed over time in response to these issues. We have attempted to illustrate these changes in Table 11.1. The overriding necessity of performing spelling correction, parsing, modeling, planning the response, and actually generating the output within 2 sec, dominated our thinking as we built the system. Then we briefly recount how the time problem and the natural language problems affected some software engineering decisions and we give a brief history of the system development process. Finally, we close with some lessons learned.
