Qualitative & Semi-Quantitative Reasoning Techniques for Engineering Projects at Conceptual Stage

During the development of engineering projects, the level of uncertainty is not static. The level of uncertainty typically diminishes from the early, conceptual stages of the project to the latter, detailed stages. At the present time there are many tools available to the engineer for reasoning with relatively low levels of uncertainty. Unfortunately there are few resources available for drawing sound conclusions from information that is characterized by a high level of uncertainty. Since decisions made early in the project cycle generally have a greater financial impact than those made later, it is worthwhile to investigate tools which are able to provide  systematic and logical evaluation of preliminary or conceptual designs. This paper investigates sound techniques for evaluating projects at the early stages, including qualitative reasoning and semi-quantitative reasoning. The paper shows that qualitative analysis methods enable the engineer to reason with a high level of abstraction. As a normal engineering project progresses, more numeric information becomes available, and the results of semi-quantitative reasoning become more useful.