The paper Constraint-Based Runtime Prediction of SLA Violations in Service Orchestrations, co-authored by IMDEA Software Institute and UPM Researchers Dragan Ivanovic, Manuel Carro, and Manuel Hermenegildo, was selected as the Best Paper Award at ICSOC 2011, the 9th International Conference on Service Computing held at the Paphos, Cyprus, Dec 5–8, 2011.
The paper presents and evaluates a technique to detect ahead of time whether there will be or not SLA violations in service orchestrations, and to determine under which conditions these will (or will not) happen. The technique uses a model of the process which can evolve as the process executes, thus making it possible to reflect dynamic changes. At every inspection point, the continuation of the process model is sent to the predictor which produces a constraint model by means of symbolic execution using a constraint-generating interpreter. The constraint system is fed into a Prolog-based constraint solver which is, additionally, given boundary conditions to represent scenarios of failure and non-failure. The results of the constraint solver indicate the cases under which these scenarios will or may occur. Evaluations under realistic conditions obtained using the Microsoft Workflow Engine indicate significant prediction capacity with very small numbers of false positives / negatives.
