The ORIS Tool: Quantitative Evaluation of Non-Markovian Systems

Abstract

We present the next generation of ORIS, a toolbox for quantitative evaluation of concurrent models with non-Markovian timers. The tool shifts its focus from timed models to stochastic ones, it includes a new graphical user interface, new analysis methods and a Java Application Programming Interface (API). Models can be specified as Stochastic Time Petri Nets (STPNs) through the graphical editor, validated using an interactive token game, and analyzed through several techniques to compute instantaneous or cumulative rewards. STPNs can also be exported as Java code to conduct extensive parametric studies through the Java library, now distributed as open-source. A well-engineered software architecture allows the user to implement new features for STPNs, new modeling formalisms, and new analysis methods. The most distinctive features of ORIS include transient and steady-state analysis of STPNs modeling Markov Regenerative Processes (MRPs), and transient analysis of STPNs modeling generalized semi-Markov processes. ORIS also supports state-space analysis of Time Petri Nets (TPNs), simulation of STPNs, and standard analysis techniques for continuous-time Markov chains or MRPs with at most one non-exponential timer in each state. We illustrate the general workflow for the application of ORIS to the modeling and evaluation of non-functional requirements of software-intensive systems.