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Exact state set representations in the verification of linear hybrid systems with large discrete state space
 In Automated Technology for Verification and Analysis, ATVA’07, volume 4762 of LNCS
, 2007
"... Copyright c © June 2007 by the author(s) ..."
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Symbolic reachability analysis of lazy linear hybrid automata
 in FORMATS, ser. Lecture Notes in Computer Science, J.F. Raskin and
, 2007
"... Abstract. Lazy linear hybrid automata (LLHA) model the discrete time behavior of control systems containing finiteprecision sensors and actuators interacting with their environment under bounded inertial delays. In this paper, we present a symbolic technique for reachability analysis of lazy linear ..."
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Cited by 14 (8 self)
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Abstract. Lazy linear hybrid automata (LLHA) model the discrete time behavior of control systems containing finiteprecision sensors and actuators interacting with their environment under bounded inertial delays. In this paper, we present a symbolic technique for reachability analysis of lazy linear hybrid automata. The model permits invariants and guards to be nonlinear predicates but requires flow values to be constants. Assuming finite precision, flows represented by uniform linear predicates can be reduced to those containing values from a finite set of constants. We present an abstraction hierarchy for LLHA. Our verification technique is based on bounded model checking and kinduction for reachability analysis at different levels of the abstraction hierarchy within an abstractionrefinement framework. The counterexamples obtained during BMC are used to construct refinements in each iteration. Our technique is practical and compares favorably with stateoftheart tools, as demonstrated on examples that include the Air Traffic Alert and Collision Avoidance System (TCAS). 1
Undecidability of quantized state feedback control for discrete time linear hybrid systems
 In Proc. of ICTAC, LNCS 7521
, 2012
"... Abstract. We show that the existence of a quantized controller for a given Discrete Time Linear Hybrid System (DTLHS) is undecidable. This is a relevant class of controllers since control software always implements a quantized controller. Furthermore, we investigate the relationship between dense ..."
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Cited by 6 (5 self)
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Abstract. We show that the existence of a quantized controller for a given Discrete Time Linear Hybrid System (DTLHS) is undecidable. This is a relevant class of controllers since control software always implements a quantized controller. Furthermore, we investigate the relationship between dense time modelling and discrete time modelling by showing that any Rectangular Hybrid Automaton (and thus, any Timed Automaton) can be modelled as a DTLHS. 1
OntheFly Control Software Synthesis ⋆
"... Abstract. The Model Based Design approach for Hybrid Systems control software synthesis is particularly appealing since Formal System Level Specifications are usually much easier to define than the control software itself. In this setting, Design Space Exploration has the goal to find a suitable (wi ..."
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Cited by 1 (0 self)
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Abstract. The Model Based Design approach for Hybrid Systems control software synthesis is particularly appealing since Formal System Level Specifications are usually much easier to define than the control software itself. In this setting, Design Space Exploration has the goal to find a suitable (with respect to costs and performance) choice for system design parameters. Unfortunately, a substantial part of the time devoted to design space exploration is spent trying to solve control software synthesis problems that do not have a solution. We present an onthefly algorithm to control software synthesis that enables effective design space exploration by speedingup termination when no controller is found. Our experimental results show the effectiveness of our approach and how it can support a concrete realizability and schedulability analysis. 1
permission. Reachability Analysis of Lazy Linear Hybrid Automata
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permission. Symbolic Reachability Analysis of Lazy Linear Hybrid Automata
"... personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires pri ..."
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personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific
ModelBased Design of Control Software
"... Many Embedded Systems are indeed Software Based Control Systems, that is control systems whose controller consists of control software running on a microcontroller device. This motivates investigation on Formal Model Based Design approaches for automatic synthesis of embedded systems control softwar ..."
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Many Embedded Systems are indeed Software Based Control Systems, that is control systems whose controller consists of control software running on a microcontroller device. This motivates investigation on Formal Model Based Design approaches for automatic synthesis of embedded systems control software. We present an algorithm, along with a tool QKS implementing it, that from a formal model (as a Discrete Time Linear Hybrid System) of the controlled system (plant), implementation specifications (that is, number of bits in the AnalogtoDigital, AD, conversion) and System Level Formal Specifications (that is, safety and liveness requirements for the closed loop system) returns correctbyconstruction control software that has a Worst Case Execution Time (WCET) linear in the number of AD bits and meets the given specifications. We show feasibility of our approach by presenting experimental results on using it to synthesize control software for a buck DCDC converter, a widely used mixedmode analog circuit, and for the inverted pendulum.
Synthesis of Implementable Control Strategies for Lazy Linear Hybrid Automata
"... Abstract—In the last few years hybrid automata have been widely applied in the modeling and verification of hybrid systems, but their related formal verification techniques usually rely on unimplementable assumptions to which a concrete control strategy cannot adhere. For this reason, once a hybrid ..."
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Abstract—In the last few years hybrid automata have been widely applied in the modeling and verification of hybrid systems, but their related formal verification techniques usually rely on unimplementable assumptions to which a concrete control strategy cannot adhere. For this reason, once a hybrid model of the system has been proved to be correct with respect to the desired properties, it would be valuable to derive a correctbyconstruction implementable control strategy for such a model. This work discusses a new methodology and a corresponding toolchain that allows to synthesize an implementable control strategy for the class of hybrid automata named Lazy Linear Hybrid Automata (LLHA). LLHA model the discrete time behavior of control systems containing finiteprecision sensors and actuators interacting with their environment under bounded delays. I.
Publisher: Sonderforschungsbereich/Transregio 14 AVACS (Automatic Verification and Analysis of Complex Systems)
, 2011
"... PTIME parametric verification of safety properties for reasonable linear hybrid automata by ..."
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PTIME parametric verification of safety properties for reasonable linear hybrid automata by