Abstract
Agile methodologies and Extreme programming are the new and highly promising endeavors in Software Engineering. By addressing the important issue of dealing with continuously changing requirements we are faced with panoply of new problems and a genuine need to revisit some principles and classic models of software developments. When it comes to the management of software projects and a way in which we are looking at the software processes and underlying practices, it becomes apparent that in the management practices the issue of uncertainty needs to be quantified and fully addressed. Similarly, it becomes of interest to develop lightweight models of software quality and software processes that are easy to construct and modify as well are transparent to the developer and manager. Given these arguments, in this study we propose logic models based upon the mechanisms of multivalued and fuzzy logic. The realization of such models gives rise to so-called logic networks that are easy to construct, calibrate and interpret.