Towards a Model-Based Framework for Integrating Usability and Software   Engineering Life Cycles
  In this position paper we propose a process model that provides a development infrastructure in which the usability engineering and software engineering life cycles co-exist in complementary roles. We describe the motivation, hurdles, rationale, arguments, and implementation plan for the need, specification, and the usefulness of such a model. 
Pardha S. Pyla, Manuel A. Perez-Quinones, James D. Arthur & H. Rex   Hartson