Dependability Evaluation and the Optimization of Performability

A new performance and performability modeling tool is introduced in this paper. PENE-LOPE is the rst tool which incorporates evaluation and optimization algorithms. It is the result of a combination between the performability modeling concept and Markov decision theory. Diierent algorithms are adopted and included in the tool under the unifying paradigm of reconngurability as the basis for adaptation and optimization. In addition to transient and steady-state performability measures, also transient and stationary control functions can be computed and graphically presented. Model speciication and speciication of transient or stationary control functions can be separately performed and deliberately combined with each other. Besides providing a new modeling paradigm, the tool supports model creation, experimentation , storage and presentation of results by means of an easily usable interface and an integrated model data base system.