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620
Tractable Multiagent Planning for Epistemic Goals
 In Proceedings of the First International Joint Conference on Autonomous Agents and Multiagent Systems (AAMAS2002
, 2002
"... agent or group of agents. In this paper, we address the problem of how plans might be developed for a group of agents to cooperate to bring about such a goal. We present a novel approach to this problem, in which the problem is formulated as one of model checking in Alternating Temporal Epistemic Lo ..."
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Cited by 87 (11 self)
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agent or group of agents. In this paper, we address the problem of how plans might be developed for a group of agents to cooperate to bring about such a goal. We present a novel approach to this problem, in which the problem is formulated as one of model checking in Alternating Temporal Epistemic Logic (ATEL). After introducing this logic, we present a model checking algorithm for it, and show that the model checking problem for this logic is tractable. We then show how multiagent planning can be treated as a model checking problem in ATEL, and discuss the related issue of checking knowledge preconditions for multiagent plans. We illustrate the approach with an example. We then describe how this example was implemented using the MOCHA model checking system, and conclude by discussing the relationship of our work with that of others in the planning and speech acts communities.
Branching vs. Linear Time: Final Showdown
 Proceedings of the 2001 Conference on Tools and Algorithms for the Construction and Analysis of Systems, TACAS 2001 (LNCS Volume 2031
, 2001
"... The discussion of the relative merits of linear versus branchingtime frameworks goes back to early 1980s. One of the beliefs dominating this discussion has been that "while specifying is easier in LTL (lineartemporal logic), verification is easier for CTL (branchingtemporal logic)". ..."
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Cited by 80 (8 self)
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The discussion of the relative merits of linear versus branchingtime frameworks goes back to early 1980s. One of the beliefs dominating this discussion has been that "while specifying is easier in LTL (lineartemporal logic), verification is easier for CTL (branchingtemporal logic)". Indeed, the restricted syntax of CTL limits its expressive power and many important behaviors (e.g., strong fairness) can not be specified in CTL. On the other hand, while model checking for CTL can be done in time that is linear in the size of the specification, it takes time that is exponential in the specification for LTL. Because of these arguments, and for historical reasons, the dominant temporal specification language in industrial use is CTL.
LTL with the freeze quantifier and register automata
 In LICS’06
, 2006
"... Temporal logics, firstorder logics, and automata over data words have recently attracted considerable attention. A data word is a word over a finite alphabet, together with a datum (an element of an infinite domain) at each position. Examples include timed words and XML documents. To refer to the d ..."
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Cited by 75 (7 self)
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Temporal logics, firstorder logics, and automata over data words have recently attracted considerable attention. A data word is a word over a finite alphabet, together with a datum (an element of an infinite domain) at each position. Examples include timed words and XML documents. To refer to the data, temporal logics are extended with the freeze quantifier, firstorder logics with predicates over the data domain, and automata with registers or pebbles. We investigate relative expressiveness and complexity of standard decision problems for LTL with the freeze quantifier (LTL ↓), 2variable firstorder logic (FO 2) over data words, and register automata. The only predicate available on data is equality. Previously undiscovered connections among those formalisms, and to counter automata with incrementing errors, enable us to answer several questions left open in recent literature. We show that the futuretime fragment of LTL ↓ which corresponds to FO 2 over finite data words can be extended considerably while preserving decidability, but at the expense of nonprimitive recursive complexity, and that most of further extensions are undecidable. We also prove that surprisingly, over infinite data words, LTL ↓ without the ‘until’ operator, as well as nonemptiness of oneway universal register automata, are undecidable even when there is only 1 register. 1.
A GameBased Verification of NonRepudiation and Fair Exchange Protocols
, 2001
"... . In this paper, we report on a recent work for the verication of nonrepudiation ..."
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Cited by 72 (3 self)
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. In this paper, we report on a recent work for the verication of nonrepudiation
Concurrent Reachability Games
, 2008
"... We consider concurrent twoplayer games with reachability objectives. In such games, at each round, player 1 and player 2 independently and simultaneously choose moves, and the two choices determine the next state of the game. The objective of player 1 is to reach a set of target states; the objecti ..."
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Cited by 68 (22 self)
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We consider concurrent twoplayer games with reachability objectives. In such games, at each round, player 1 and player 2 independently and simultaneously choose moves, and the two choices determine the next state of the game. The objective of player 1 is to reach a set of target states; the objective of player 2 is to prevent this. These are zerosum games, and the reachability objective is one of the most basic objectives: determining the set of states from which player 1 can win the game is a fundamental problem in control theory and system verification. There are three types of winning states, according to the degree of certainty with which player 1 can reach the target. From type1 states, player 1 has a deterministic strategy to always reach the target. From type2 states, player 1 has a randomized strategy to reach the target with probability 1. From type3 states, player 1 has for every real ε> 0 a randomized strategy to reach the target with probability greater than 1 − ε. We show that for finite state spaces, all three sets of winning states can be computed in polynomial time: type1 states in linear time, and type2 and type3 states in quadratic time. The algorithms to compute the three sets of winning states also enable the construction of the winning and spoiling strategies.
A static compliancechecking framework for business process models
, 2007
"... Regulatory compliance of business operations is a critical problem for enterprises. As enterprises increasingly use business process management systems to automate their business processes, technologies to automatically check the compliance of process models against compliance rules are becoming im ..."
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Cited by 64 (0 self)
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Regulatory compliance of business operations is a critical problem for enterprises. As enterprises increasingly use business process management systems to automate their business processes, technologies to automatically check the compliance of process models against compliance rules are becoming important. In this paper, we present a method to improve the reliability and minimize the risk of failure of business process management systems from a compliance perspective. The proposed method allows separate modeling of both process models and compliance concerns. Business process models expressed in the Business Process Execution Language are transformed into picalculus and then into finite state machines. Compliance rules captured in the graphical Business Property Specification Language are translated into linear temporal logic. Thus, process models can be verified against these compliance rules by means of modelchecking technology. The benefit of our method is threefold: Through the automated verification of a large set of business process models, our approach increases deployment efficiency and lowers the risk of installing noncompliant processes; it reduces the cost associated with inspecting business process models for compliance; and compliance checking may ensure compliance of new process models before their execution and thereby increase the reliability of business operations in general.
Discounting the future in systems theory
 In Automata, Languages, and Programming, LNCS 2719
, 2003
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The Element of Surprise in Timed Games
"... We consider concurrent twoperson games played in real time, in which the players decide both which action to play, and when to play it. Such timed games differ from untimed games in two essential ways. First, players can take each other by surprise, because actions are played with delays that canno ..."
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Cited by 58 (13 self)
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We consider concurrent twoperson games played in real time, in which the players decide both which action to play, and when to play it. Such timed games differ from untimed games in two essential ways. First, players can take each other by surprise, because actions are played with delays that cannot be anticipated by the opponent. Second, a player should not be able to win the game by preventing time from diverging. We present a model of timed games that preserves the element of surprise and accounts for time divergence in a way that treats both players symmetrically and applies to all !regular winning conditions.
On The Logic Of Cooperation And Propositional Control
, 2005
"... Cooperation logics have recently begun to attract attention within the multiagent systems community. Using a cooperation logic, it is possible to represent and reason about the strategic powers of agents and coalitions of agents in gamelike multiagent systems. These powers are generally assumed t ..."
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Cited by 57 (23 self)
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Cooperation logics have recently begun to attract attention within the multiagent systems community. Using a cooperation logic, it is possible to represent and reason about the strategic powers of agents and coalitions of agents in gamelike multiagent systems. These powers are generally assumed to be implicitly defined within the structure of the environment, and their origin is rarely discussed. In this paper, we study a cooperation logic in which agents are each assumed to control a set of propositional variablesthe powers of agents and coalitions then derive from the allocation of propositions to agents. The basic modal constructs in this Coalition Logic of Propositional Control (CLPC) allow us to express the fact that a group of agents can cooperate to bring about a certain state of affairs. After motivating and introducing CLPC, we provide a complete axiom system for the logic, investigate the issue of characterising control in CLPC with respect to the underlying power structures of the logic, and formally investigate the relationship between CLPC and Pauly's Coalition Logic. We then show that the model checking and satisfiability problems for CLPC are both PSPACEcomplete, and conclude by discussing our results and how CLPC sits in relation to other logics of cooperation.