The Experts below are selected from a list of 54522 Experts worldwide ranked by ideXlab platform
George J. Pappas - One of the best experts on this subject based on the ideXlab platform.
-
robustness of Temporal Logic specifications for continuous time signals
Theoretical Computer Science, 2009Co-Authors: Georgios Fainekos, George J. PappasAbstract:In this paper, we consider the robust interpretation of Metric Temporal Logic (MTL) formulas over signals that take values in metric spaces. For such signals, which are generated by systems whose states are equipped with non-trivial metrics, for example continuous or hybrid, robustness is not only natural, but also a critical measure of system performance. Thus, we propose multi-valued semantics for MTL formulas, which capture not only the usual Boolean satisfiability of the formula, but also topoLogical information regarding the distance, @e, from unsatisfiability. We prove that any other signal that remains @e-close to the initial one also satisfies the same MTL specification under the usual Boolean semantics. Finally, our framework is applied to the problem of testing formulas of two fragments of MTL, namely Metric Interval Temporal Logic (MITL) and closed Metric Temporal Logic (clMTL), over continuous-time signals using only discrete-time analysis. The motivating idea behind our approach is that if the continuous-time signal fulfills certain conditions and the discrete-time signal robustly satisfies the Temporal Logic specification, then the corresponding continuous-time signal should also satisfy the same Temporal Logic specification.
-
Temporal Logic planning for dynamic models
Automatica, 2009Co-Authors: Georgios E. Fainekos, Antoine Girard, Haddas Kress-gazit, George J. PappasAbstract:In this paper, we address the Temporal Logic motion planning problem for mobile robots that are modeled by second order dynamics. Temporal Logic specifications can capture the usual control specifications such as reachability and invariance as well as more complex specifications like sequencing and obstacle avoidance. Our approach consists of three basic steps. First, we design a control law that enables the dynamic model to track a simpler kinematic model with a globally bounded error. Second, we built a robust Temporal Logic specification that takes into account the tracking errors of the first step. Finally, we solve the new robust Temporal Logic path planning problem for the kinematic model using automata theory and simple local vector fields. The resulting continuous time trajectory is provably guaranteed to satisfy the initial user specification.
-
Temporal Logic motion planning for dynamic robots
Automatica, 2009Co-Authors: Georgios E. Fainekos, Antoine Girard, Hadas Kressgazit, George J. PappasAbstract:In this paper, we address the Temporal Logic motion planning problem for mobile robots that are modeled by second order dynamics. Temporal Logic specifications can capture the usual control specifications such as reachability and invariance as well as more complex specifications like sequencing and obstacle avoidance. Our approach consists of three basic steps. First, we design a control law that enables the dynamic model to track a simpler kinematic model with a globally bounded error. Second, we built a robust Temporal Logic specification that takes into account the tracking errors of the first step. Finally, we solve the new robust Temporal Logic path planning problem for the kinematic model using automata theory and simple local vector fields. The resulting continuous time trajectory is provably guaranteed to satisfy the initial user specification.
Yves Bontemps - One of the best experts on this subject based on the ideXlab platform.
-
Temporal Logic for scenario-based specifications
Lecture Notes in Computer Science, 2005Co-Authors: Hillel Kugler, David Harel, Amir Pnueli, Yves BontempsAbstract:We provide semantics for the powerful scenario-based language of live sequence charts (LSCs). We show how the semantics of live sequence charts can be captured using Temporal Logic. This is done by studying various subsets of the LSC language and providing an explicit translation into Temporal Logic. We show how a kernel subset of the LSC language (which omits variables, for example) can be embedded within the Temporal Logic CTL*. For this kernel subset the embedding is a strict inclusion. We show that existential charts can be expressed using the branching Temporal Logic CTL while universal charts are in the intersection of linear Temporal Logic and branching Temporal Logic LTL n CTL. Since our translations are efficient, the work described here may be used in the development of tools for analyzing and executing scenario-based requirements and for verifying systems against such requirements.
-
TACAS - Temporal Logic for scenario-based specifications
Tools and Algorithms for the Construction and Analysis of Systems, 2005Co-Authors: Hillel Kugler, David Harel, Amir Pnueli, Yves BontempsAbstract:We provide semantics for the powerful scenario-based language of live sequence charts (LSCs). We show how the semantics of live sequence charts can be captured using Temporal Logic. This is done by studying various subsets of the LSC language and providing an explicit translation into Temporal Logic. We show how a kernel subset of the LSC language (which omits variables, for example) can be embedded within the Temporal Logic CTL*. For this kernel subset the embedding is a strict inclusion. We show that existential charts can be expressed using the branching Temporal Logic CTL while universal charts are in the intersection of linear Temporal Logic and branching Temporal Logic LTL ∩ CTL. Since our translations are efficient, the work described here may be used in the development of tools for analyzing and executing scenario-based requirements and for verifying systems against such requirements.
Georgios E. Fainekos - One of the best experts on this subject based on the ideXlab platform.
-
Temporal Logic planning for dynamic models
Automatica, 2009Co-Authors: Georgios E. Fainekos, Antoine Girard, Haddas Kress-gazit, George J. PappasAbstract:In this paper, we address the Temporal Logic motion planning problem for mobile robots that are modeled by second order dynamics. Temporal Logic specifications can capture the usual control specifications such as reachability and invariance as well as more complex specifications like sequencing and obstacle avoidance. Our approach consists of three basic steps. First, we design a control law that enables the dynamic model to track a simpler kinematic model with a globally bounded error. Second, we built a robust Temporal Logic specification that takes into account the tracking errors of the first step. Finally, we solve the new robust Temporal Logic path planning problem for the kinematic model using automata theory and simple local vector fields. The resulting continuous time trajectory is provably guaranteed to satisfy the initial user specification.
-
Temporal Logic motion planning for dynamic robots
Automatica, 2009Co-Authors: Georgios E. Fainekos, Antoine Girard, Hadas Kressgazit, George J. PappasAbstract:In this paper, we address the Temporal Logic motion planning problem for mobile robots that are modeled by second order dynamics. Temporal Logic specifications can capture the usual control specifications such as reachability and invariance as well as more complex specifications like sequencing and obstacle avoidance. Our approach consists of three basic steps. First, we design a control law that enables the dynamic model to track a simpler kinematic model with a globally bounded error. Second, we built a robust Temporal Logic specification that takes into account the tracking errors of the first step. Finally, we solve the new robust Temporal Logic path planning problem for the kinematic model using automata theory and simple local vector fields. The resulting continuous time trajectory is provably guaranteed to satisfy the initial user specification.
Patrice Godefroid - One of the best experts on this subject based on the ideXlab platform.
-
Temporal Logic Query Checking (Extended Abstract)
2001Co-Authors: Glenn R. Bruns, Patrice GodefroidAbstract:A Temporal Logic query checker takes as input a Kripke structure and a Temporal Logic formula with a hole, and returns the set of propositional formulas that, when put in the hole, are satisfied by the Kripke structure. By allowing the Temporal properties of a system to be discovered, query checking is useful in the study and reverse engineering of systems. Temporal Logic query checking was first proposed in [2]. In this paper, we generalize and simplify Chan’s work by showing how a new class of alternating automata can be used for query checking with a wide range of Temporal Logics.
-
LICS - Temporal Logic query checking
Proceedings 16th Annual IEEE Symposium on Logic in Computer Science, 1Co-Authors: Glenn Bruns, Patrice GodefroidAbstract:A Temporal Logic query checker takes as input a Kripke structure and a Temporal Logic formula with a hole, and returns the set of propositional formulas that, when put in the hole, are satisfied by the Kripke structure. By allowing the Temporal properties of a system to be discovered, query checking is useful in the study and reverse engineering of systems. Temporal Logic query checking was first proposed by W. Chan (2000). In this paper, we generalize and simplify Chan's work by showing how a new class of alternating automata can be used for query checking with a wide range of Temporal Logics.
Orna Kupferman - One of the best experts on this subject based on the ideXlab platform.
-
Alternating-time Temporal Logic
Proceedings 38th Annual Symposium on Foundations of Computer Science, 2002Co-Authors: Rajeev Alur, Thomas A. Henzinger, Orna KupfermanAbstract:Temporal Logic comes in two varieties: linear-time Temporal Logic assumes implicit universal quantification over all paths that are generated by the execution of a system; branching-time Temporal Logic allows explicit existential and universal quantification over all paths. We introduce a third, more general variety of Temporal Logic: alternating-time Temporal Logic offers selective quantification over those paths that are possible outcomes of games, such as the game in which the system and the environment alternate moves. While linear-time and branching-time Logics are natural specification languages for closed systems, alternating-time Logics are natural specification languages for open systems. For example, by preceding the Temporal operator "eventually" with a selective path quantifier, we can specify that in the game between the system and the environment, the system has a strategy to reach a certain state. The problems of receptiveness, realizability, and controllability can be formulated as model-checking problems for alternating-time formulas. Depending on whether or not we admit arbitrary nesting of selective path quantifiers and Temporal operators, we obtain the two alternating-time Temporal Logics ATL and ATL*.ATL and ATL* are interpreted over concurrent game structures. Every state transition of a concurrent game structure results from a choice of moves, one for each player. The players represent individual components and the environment of an open system. Concurrent game structures can capture various forms of synchronous composition for open systems, and if augmented with fairness constraints, also asynchronous composition. Over structures without fairness constraints, the model-checking complexity of ATL is linear in the size of the game structure and length of the formula, and the symbolic model-checking algorithm for CTL extends with few modifications to ATL. Over structures with weak-fairness constraints, ATL model checking requires the solution of 1-pair Rabin games, and can be done in polynomial time. Over structures with strong-fairness constraints, ATL model checking requires the solution of games with Boolean combinations of Büchi conditions, and can be done in PSPACE. In the case of ATL*, the model-checking problem is closely related to the synthesis problem for linear-time formulas, and requires doubly exponential time.
-
alternating time Temporal Logic
International Symposium on Compositionality: Significant Difference, 1997Co-Authors: Rajeev Alur, Thomas A. Henzinger, Orna KupfermanAbstract:Temporal Logic comes in two varieties: linear-time Temporal Logic assumes implicit universal quantification over all paths that are generated by system moves; branching-time Temporal Logic allows explicit existential and universal quantification over all paths. We introduce a third, more general variety of Temporal Logic: alternating-time Temporal Logic offers selective quantification over those paths that are possible outcomes of games, such as the game in which the system and the environment alternate moves. While linear-time and branching-time Logics are natural specification languages for closed systems, alternating-time Logics are natural specification languages for open systems. For example, by preceding the Temporal operator "eventually" with a selective path quantifier, we can specify that in the game between the system and the environment, the system has a strategy to reach a certain state. Also the problems of receptiveness, realizability, and controllability can be formulated as model-checking problems for alternating-time formulas. Depending on whether we admit arbitrary nesting of selective path quantifiers and Temporal operators, we obtain the two alternating-time Temporal Logics ATL and ATL*. We interpret the formulas of ATL and ATL* over alternating transition systems. While in ordinary transition systems, each transition corresponds to a possible step of the system, in alternating transition systems, each transition corresponds to a possible move in the game between the system and the environment. Fair alternating transition systems can capture both synchronous and asynchronous compositions of open systems. For synchronous systems, the expressive power of ATL beyond CTL comes at no cost: the model-checking complexity of synchronous ATL is linear in the size of the system and the length of the formula. The symbolic model-checking algorithm for CTL extends with few modifications to synchronous ATL, and with some work, also to asynchronous ATL, whose model-checking complexity is quadratic. This makes ATL an obvious candidate for the automatic verification of open systems. In the case of ATL*, the model-checking problem is closely related to the synthesis problem for linear-time formulas, and requires doubly exponential time for both synchronous and asynchronous systems.
-
Alternating-time Temporal Logic
Proceedings 38th Annual Symposium on Foundations of Computer Science, 1997Co-Authors: Rajeev Alur, Thomas A. Henzinger, Orna KupfermanAbstract:Temporal Logic comes in two varieties: linear-time Temporal Logic assumes implicit universal quantification over all paths that are generated by system moves; branching-time Temporal Logic allows explicit existential and universal quantification over all paths. We introduce a third, more general variety of Temporal Logic: alternating-time Temporal Logic offers selective quantification over those paths that are possible outcomes of games, such as the game in which the system and the environment alternate moves. While linear-time and branching-time Logics are natural specification languages for closed systems, alternating-time Logics are natural specification languages for open systems. For example, by preceding the Temporal operator "eventually" with a selective path quantifier, we can specify that in the game between the system and the environment, the system has a strategy to reach a certain state. Also the problems of receptiveness, realizability, and controllability can be formulated as model-checking problems for alternating-time formulas.
-
FOCS - Alternating-time Temporal Logic
Proceedings 38th Annual Symposium on Foundations of Computer Science, 1Co-Authors: Rajeev Alur, Thomas A. Henzinger, Orna KupfermanAbstract:Temporal Logic comes in two varieties: linear-time Temporal Logic assumes implicit universal quantification over all paths that are generated by system moves; branching-time Temporal Logic allows explicit existential and universal quantification over all paths. We introduce a third, more general variety of Temporal Logic: alternating-time Temporal Logic offers selective quantification over those paths that are possible outcomes of games, such as the game in which the system and the environment alternate moves. While linear-time and branching-time Logics are natural specification languages for closed systems, alternating-time Logics are natural specification languages for open systems. For example, by preceding the Temporal operator "eventually" with a selective path quantifier, we can specify that in the game between the system and the environment, the system has a strategy to reach a certain state. Also the problems of receptiveness, realizability, and controllability can be formulated as model-checking problems for alternating-time formulas.