An Individual-based Probabilistic Model for Fish Stock Simulation

We define an individual-based probabilistic model of a sole (Solea solea) behaviour. The individual model is given in terms of an Extended Probabilistic Discrete Timed Automaton (EPDTA), a new formalism that is introduced in the paper and that is shown to be interpretable as a Markov decision process. A given EPDTA model can be probabilistically model-checked by giving a suitable translation into syntax accepted by existing model-checkers. In order to simulate the dynamics of a given population of soles in different environmental scenarios, an agent-based simulation environment is defined in which each agent implements the behaviour of the given EPDTA model. By varying the probabilities and the characteristic functions embedded in the EPDTA model it is possible to represent different scenarios and to tune the model itself by comparing the results of the simulations with real data about the sole stock in the North Adriatic sea, available from the recent project SoleMon. The simulator is presented and made available for its adaptation to other species.Comment: In Proceedings AMCA-POP 2010, arXiv:1008.314

A Survey on IT-Techniques for a Dynamic Emergency Management in Large Infrastructures

This deliverable is a survey on the IT techniques that are relevant to the three use cases of the project EMILI. It describes the state-of-the-art in four complementary IT areas: Data cleansing, supervisory control and data acquisition, wireless sensor networks and complex event processing. Even though the deliverable’s authors have tried to avoid a too technical language and have tried to explain every concept referred to, the deliverable might seem rather technical to readers so far little familiar with the techniques it describes

Design Environments for Complex Systems

The paper describes an approach for modeling complex systems by hiding as much formal details as possible from the user, still allowing verification and simulation of the model. The interface is based on UML to make the environment available to the largest audience. To carry out analysis, verification and simulation we automatically extract process algebras specifications from UML models. The results of the analysis is then reflected back in the UML model by annotating diagrams. The formal model includes stochastic information to handle quantitative parameters. We present here the stochastic -calculus and we discuss the implementation of its probabilistic support that allows simulation of processes. We exploit the benefits of our approach in two applicative domains: global computing and systems biology

An executable Theory of Multi-Agent Systems Refinement

Complex applications such as incident management, social simulations, manufacturing applications, electronic auctions, e-institutions, and business to business applications are pervasive and important nowadays. Agent-oriented methodology is an advance in abstractionwhich can be used by software developers to naturally model and develop systems for suchapplications. In general, with respect to design methodologies, what it may be important tostress is that control structures should be added at later stages of design, in a natural top-downmanner going from specifications to implementations, by refinement. Too much detail (be itfor the sake of efficiency) in specifications often turns out to be harmful. To paraphrase D.E.Knuth, “Premature optimization is the root of all evil” (quoted in ‘The Unix ProgrammingEnvironment’ by Kernighan and Pine, p. 91).The aim of this thesis is to adapt formal techniques to the agent-oriented methodologyinto an executable theory of refinement. The justification for doing so is to provide correctagent-based software by design. The underlying logical framework of the theory we proposeis based on rewriting logic, thus the theory is executable in the same sense as rewriting logicis. The storyline is as follows. We first motivate and explain constituting elements of agentlanguages chosen to represent both abstract and concrete levels of design. We then proposea definition of refinement between agents written in such languages. This notion of refinement ensures that concrete agents are correct with respect to the abstract ones. The advantageof the definition is that it easily leads to formulating a proof technique for refinement viathe classical notion of simulation. This makes it possible to effectively verify refinement bymodel-checking. Additionally, we propose a weakest precondition calculus as a deductivemethod based on assertions which allow to prove correctness of infinite state agents. Wegeneralise the refinement relation from single agents to multi-agent systems in order to ensure that concrete multi-agent systems refine their abstractions. We see multi-agent systemsas collections of coordinated agents, and we consider coordination artefacts as being basedeither on actions or on normative rules. We integrate these two orthogonal coordinationmechanisms within the same refinement theory extended to a timed framework. Finally, wediscuss implementation aspects.LEI Universiteit LeidenFoundations of Software Technolog