12 research outputs found

    ParaPlan: A Tool for Parallel Reachability Analysis of Planar Polygonal Differential Inclusion Systems

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    Andrei Sandler, and Olga Tveretina, ‘ParaPlan: A Tool for Parallel Reachability Analysis of Planar Polygonal Differential Inclusion Systems’, in Patricia Bouyer, Andrea Orlandini and Pierluigi San Pietro, eds. Proceedings Eight International Symposium on Games, Automata, Logics and Formal Verification (GandALF 2017), Rome, Italy, 20-22 September 2017, Electronic Proceedings in Theoretical Computer Science, Vol. 256: 283-296, September 2017. © 2017 The Author(s). This work is licensed under the Creative Commons Attribution License CC BY 4.0 https://creativecommons.org/licenses/by/4.0/We present the ParaPlan tool which provides the reachability analysis of planar hybrid systems defined by differential inclusions (SPDI). It uses the parallelized and optimized version of the algorithm underlying the SPeeDI tool. The performance comparison demonstrates the speed-up of up to 83 times with respect to the sequential implementation on various benchmarks. Some of the benchmarks we used are randomly generated with the novel approach based on the partitioning of the plane with Voronoi diagrams

    Supervisão, comando e controlo para sistemas robóticos

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    Mestrado em Engenharia Electrotécnica e de Computadores. Área de Especialização em Sistemas AutónomosEsta dissertação aborda a temática da interacção homem-máquina no controlo, comando e supervisão de veículos autónomos. O tópico de Supervisão tem vindo a ganhar importância com o surgimento de novos e florescentes nichos de mercado para aplicação de sistemas robóticos tais como a monitorização ambiental e a monitorização de infra-estruturas, onde se destaca, a t´titulo de exemplo, a robótica submarina que tem sido impulsionada pela indústria extractiva em off-shore e pela indústria da construção de infraestruturas costeiras ou em off-shore. As funcionalidades apresentadas por estes sistemas ainda dependem fortemente da supervisão do utilizador humano. As características da supervisão, por sua vez, dependem do grau de autonomia com que estes sistemas são capazes de desempenhar as tarefas que lhes são atribuídas. As questões de supervisão já há algum tempo têm despertado em si alguma atenção por parte da comunidade robótica motivo pelo qual se assiste `a transferência de projectos do seio da comunidade de ”I&D” para a comunidade de desenvolvimento e serviços, onde a problemática da supervisão assume um papel fundamental para o sucesso das aplicações dos sistemas robóticos. O trabalho desenvolvido permitiu a apresentação de uma arquitectura para a supervisão de sistemas autónomos. O contributo do trabalho apresentado nesta dissertação alicerça-se numa abordagem experimental, que através da análise de casos de estudo, ocorre ao longo de duas linhas de trabalho: uma de carácter conceptual dirigida ao projecto e que resulta numa proposta de arquitectura orientada para a supervisão; e outra que resulta em linhas orientadoras das interfaces de comando homem-máquina. A motivação para este trabalho surge como resposta aos desafios colocados pelos projectos que ocorrem no LSA/ISEP/IPP que protagonizam um papel relevante na interacção homem máquina, e que são por exemplo o futebol robótico, a recolha de dados oceanográficos (batimetria) executada por um ASV (Veículo Autónomo de Superfície) e a localização de tags”(dispositivos identificadores) dentro de edifícios fechados usando pontos de acesso de redes sem fio. Complementarmente `a solução conceptual para a supervisão desenvolvemos diferentes e variadas interfaces gráficas como elementos integrantes da interacção homem - sistema autónomo e que resultaram na implementação do sistema de supervisão da equipa de futebol robótico ISePorto e do sistema de batimetria com o veículo ROAZ. Os resultados obtidos, confirmaram que os paradigmas de supervisão tendo em conta a iniciativa mista, promovem soluções mais versáteis e operacionalmente mais eficazes.The main focus of this dissertation is the man-machine interaction problem in autonomous vehicles control and supervision. The Supervision topic has been gaining importance with the arise of new and growing market niches for robotic systems applications in environmental and infrastructures monitoring like submarine robotics supported by both off-shore extractive industry and off-shore and coast infrastructure construction industry. The systems functionalities are still strongly dependent on human supervision. The supervision characteristics are, in return, dependent on the autonomy degree of the systems capability of performing the designated tasks. The supervision problematic have gathered the attention of the robotics community for some time, in terms of the project transfer from the R&D community to service and development community, where supervision takes a fundamental role in robotic systems applications success. This dissertation’s contribute is based in an experimental approach, by analysis of study cases, along two work lines: one, of conceptual character and project driven, results in a supervision guided architecture proposal; and the other results in man-machine command interfaces guidelines. This works’ motivation comes as an answer to the challenges placed by the projects in LSA/ISEP/IPP that take a relevant part in man-machine interaction, like robotics football, ocean data recovery (bathymetry) executed by an ASV (Autonomous Surface Vehicle) and the localization of tags (identifying devices) inside closed buildings using wireless net points. Complementary to the conceptual solution for supervision were developed several different graphical interfaces as integration elements in a human-autonomous system interaction and that result from ISePorto robotic football team supervision systems and the bathymetry systems with the vehicle ROAZ. The results obtained have confirmed that the supervision paradigms, considering a mixed initiative, promote more versatile and operationally more effective solutions

    Relaxing goodness is still good for SPDIs

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    Polygonal hybrid systems (SPDIs) are planar hybrid systems, whose dynamics are defined in terms of constant differential inclusions, one for each of a number of polygonal regions partitioning the plane. The reachability problem for SPDIs is known to be decidable, but depends on the goodness assumption — which states that the dynamics do not allow a trajectory to both enter and leave a region through the same edge. In this paper we extend the decidability result to generalised SPDIs (GSPDI), SPDIs not satisfying the goodness property, and give an algorithmic solution to decide reachability of such systems.peer-reviewe

    Nutzerfreundliche Modellierung mit hybriden Systemen zur symbolischen Simulation in CLP

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    Die Dissertation beinhaltet die Sprachen MODEL-HS und VYSMO zur modularen, deklarativen Beschreibung hybrider Systeme, die dem Nachweis zeit- und sicherheitskritischer Eigenschaften für die symbolische Simulation in CLP dienen. Zum Erlangen sprachtheoretischer Erkenntnisse wie Entscheidbarkeit wurden hybride Systeme neu unter formal nachweisbaren Akzeptanzbedingungen definiert, welche durch praktische Beispiele belegt sind. Weitere Ergebnisse sind eine neue Klassifikation hybrider Systeme, ein Werkzeug ROSSY, Anfragebeschreibungen und deren Transformation in temporal-logische Ausdrücke, Anfragemasken und Anwendungen für Studiensysteme und parallele Programme.The dissertation includes the languages MODEL-HS and VYSMO for modular, declarative description of hybrid systems that serve the proof of time- and safety-critical properties for symbolic simulation in CLP. For coming to language-theoretical conclusions like decidability hybrid systems are newly defined under acceptance conditions that can be formally proved and for which practical examples bear witness. A new classification of hybrid systems, a tool ROSSY, query descriptions and their transformation into temporal-logic expressions, query forms and applications for study systems and parallel programs are further results

    Relaxing goodness is still good for SPDIs

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    Polygonal hybrid systems (SPDIs) are planar hybrid systems, whose dynamics are defined in terms of constant differential inclusions, one for each of a number of polygonal regions partitioning the plane. The reachability problem for SPDIs is known to be decidable, but depends on the goodness assumption — which states that the dynamics do not allow a trajectory to both enter and leave a region through the same edge. In this paper we extend the decidability result to generalised SPDIs (GSPDI), SPDIs not satisfying the goodness property, and give an algorithmic solution to decide reachability of such systems.peer-reviewe

    Static analysis of SPDIs for state-space reduction

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    Polygonal hybrid systems (SPDI) are a subclass of planar hybrid automata which can be represented by piecewise constant differential inclusions. The reachability problem as well as the computation of certain objects of the phase portrait, namely the viability, controllability and invariance kernels, for such systems is decidable. In this paper we show how to compute another object of an SPDI phase portrait, namely semi-separatrix curves and show how the phase portrait can be used for reducing the state-space for optimizing the reachability analysis.peer-reviewe

    Model checking polygonal differential inclusions using invariance kernels

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    Polygonal hybrid systems are a subclass of planar hybrid automata which can be represented by piecewise constant differential inclusions. Here, we identify and compute an important object of such systems’ phase portrait, namely invariance kernels. An invariant set is a set of initial points of trajectories which keep rotating in a cycle forever and the invariance kernel is the largest of such sets. We show that this kernel is a non-convex polygon and we give a non-iterative algorithm for computing the coordinates of its vertices and edges. Moreover, we present a breadth-first search algorithm for solving the reachability problem for such systems. Invariance kernels play an important role in the algorithm.peer-reviewe

    Computer-aided verification : how to trust a machine with your life

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    Mathematical predictive analysis of the behaviour of circuits and computer pro- grams is a core problem in computer science. Research in formal verification and semantics of programming languages has been an active field for a number of decades, but it was only through techniques developed over these past twenty years that they have been scaled up to work on non-trivial case-studies. This report gives an overview of a number of computer- aided formal verification areas I have been working on over these past couple of years in such a way to be accessible to computer scientists in other disciplines. Brief mention is made of problems in these areas I am actively working on. It does not purport to be an overview of the whole field of computer-aided formal verification or a detailed technical account of my research.peer-reviewe

    SPeeDI - a verification tool for polygonal hybrid systems

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    Hybrid systems combining discrete and continuous dynamics arise as mathematical models of various artificial and natural systems, and as an approximation to complex continuous systems. A very important problem in the analysis of the behavior of hybrid systems is reachability. It is well-known that for most non-trivial subclasses of hybrid systems this and all interesting verification problems are undecidable. Most of the proved decidability results rely on stringent hypothesis that lead to the existence of a finite and computable partition of the state space into classes of states which are equivalent with respect to reachability. This is the case for classes of rectangular automata [1] and hybrid automata with linear vector fields [2]. Most implemented computational procedures resort to (forward or backward) propagation of constraints, typically (unions of convex) polyhedra or ellipsoids [3, 4, 5]. In general, these techniques provide semi-decision procedures, that is, if the given final set of states is reachable, they will terminate, otherwise they may fail to. Maybe the major drawback of set-propagation, reachset approximation procedures is that they pay little attention to the geometric properties of the specific (class of) systems under analysis.peer-reviewe
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