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14
Keeping Track of the Latest Gossip in a Distributed System
 DISTRIBUTED COMPUTING
, 1997
"... We tackle a natural problem from distributed computing, involving timestamps. Let P = fp 1 ; p 2 ; : : : ; p N g be a set of computing agents or processes which synchronize with each other from time to time and exchange information about themselves and others. The gossip problem is the following: W ..."
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Cited by 11 (2 self)
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We tackle a natural problem from distributed computing, involving timestamps. Let P = fp 1 ; p 2 ; : : : ; p N g be a set of computing agents or processes which synchronize with each other from time to time and exchange information about themselves and others. The gossip problem is the following: Whenever a set P ` P meets, the processes in P must decide amongst themselves which of them has the latest information, direct or indirect, about each agent p in the system. We propose an algorithm to solve this problem which is finitestate and local. Formally, this means that our algorithm can be implemented as an asynchronous automaton.
Team Formation by SelfInterested Mobile Agents
 In Proc. 4th Australian DAIWorkshop
, 1998
"... . A process of team formation by autonomous agents in a distributed environment is presented. Since the environment is distributed, there are serious problems with communication and consistent decision making inside a team. To deal with these problems, the standard technique of token passing in ..."
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Cited by 9 (8 self)
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. A process of team formation by autonomous agents in a distributed environment is presented. Since the environment is distributed, there are serious problems with communication and consistent decision making inside a team. To deal with these problems, the standard technique of token passing in a computer network is applied. The passing cycle of the token serves as the communication route. It assures consistent decision making inside the team maintaining its organizational integrity. On the other hand it constitutes a component of the plan of the cooperative work performed by a complete team. Two algorithms for team formation are given. The first one is based on simple selfinterested agents that still can be viewed as reactive agents (see [14]) although augmented with knowledge, goal, and cooperation mechanisms. The second one is based on sophisticated selfinterested agents. Moreover, the algorithm based on fully cooperative agents, which is an adaptation of the static ...
Determinizing Asynchronous Automata
 Proceedings of the 21st International Colloquium on Automata, Languages and Programming (ICALP'94), Jerusalem (Israel) 1994, number 820 in Lecture
, 1993
"... A concurrent version of a finitestate automaton is a set of processes that cooperate in processing letters of the input. Each letter read prompts some of the processes to synchronize and decide on a joint move according to a nondeterministic transition relation. Such automata are known as asynchro ..."
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Cited by 8 (1 self)
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A concurrent version of a finitestate automaton is a set of processes that cooperate in processing letters of the input. Each letter read prompts some of the processes to synchronize and decide on a joint move according to a nondeterministic transition relation. Such automata are known as asynchronous automata. The question whether these automata can be determinized while retaining the synchronization structure has already been answered in the positive, but indirectly, by means of sophisticated algebraic techniques. In this paper we present an elementary proof, which generalizes the classic subset construction for finitestate automata. The proof uses in an essential way an earlier finitestate construction by Mukund and Sohoni for maintaining each process's latest knowledge about other processes. Our construction is only doubleexponential and thus is the first to essentially match the lower bound. Computer Science Department, Aarhus University, Ny Munkegade, DK 8000 Aarhus C, ...
Temporal Logic of Causal Knowledge
 Proc. of WoLLiC '98
, 1998
"... . Temporal logic of causal knowledge over general partially ordered structures is defined. The definition of knowledge captures the change of state due to action executions. The structures are a variant of flow event structures including prime event structures and branching processes of Petri Ne ..."
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Cited by 7 (3 self)
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. Temporal logic of causal knowledge over general partially ordered structures is defined. The definition of knowledge captures the change of state due to action executions. The structures are a variant of flow event structures including prime event structures and branching processes of Petri Nets. Modalities corresponding to the causality, independency, and indistinguishability relations are used. Formulas are interpreted over local state occurrences. The logic is proved to be decidable and a complete axiomatization is provided. Keywords: multiagent systems, knowledge, temporal logic, causality, partially ordered sets. 1 Introduction Reasoning about knowledge is one of the fundamental problems in multiagent systems. Usually, dynamic global state spaces partitioned w.r.t. the agents' information are considered [3]. In the theory of distributed systems, knowledge formulas are interpreted over infinite linear or branching runs of the systems [4, 5, 3, 9, 15, 16]. It is clear ...
Regular Trace Event Structures
, 1996
"... We propose trace event structures as a starting point for constructing effective branching time temporal logics in a noninterleaved setting. ..."
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Cited by 7 (0 self)
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We propose trace event structures as a starting point for constructing effective branching time temporal logics in a noninterleaved setting.
Gossiping, Asynchronous Automata and Zielonka's Theorem
 SCHOOL OF MATHEMATICS, SPIC SCIENCE FOUNDATION
, 1994
"... In this paper, we first tackle a natural problem from distributed computing, involving timestamps. We then show that our solution to this problem can be applied to provide a simplified proof of Zielonka's theorema fundamental result in the theory of concurrent systems. Let P = fp 1 ; p ..."
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Cited by 3 (2 self)
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In this paper, we first tackle a natural problem from distributed computing, involving timestamps. We then show that our solution to this problem can be applied to provide a simplified proof of Zielonka's theorema fundamental result in the theory of concurrent systems. Let P = fp 1 ; p 2 ; : : : ; p N g be a set of computing agents or processes which synchronize with each other from time to time and exchange information about themselves and others. The gossip problem is the following: Whenever a set P ` P meets, the processes in P must decide amongst themselves which of them has the latest information, direct or indirect, about each agent p in the system. We propose an algorithm to solve this problem which is finitestate and local. Formally, this means that our algorithm can be implemented as an asynchronous automaton. Solving the gossip problem appears to be a basic step in tackling other problems involving asynchronous automata. Here, we apply our solution to derive...
Temporal Approach to Causal Knowledge
, 2000
"... Temporal logic of causal knowledge over general partially ordered structures of local states is dened. The denition of knowledge captures the change of state due to action executions. The structures are a variant of ow event structures including prime event structures and branching processes of Petr ..."
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Cited by 3 (1 self)
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Temporal logic of causal knowledge over general partially ordered structures of local states is dened. The denition of knowledge captures the change of state due to action executions. The structures are a variant of ow event structures including prime event structures and branching processes of Petri Nets. Modalities corresponding to the causality, concurrency, and indistinguishability relations are used. Formulas are interpreted over local state occurrences. The logic is proved to be decidable and a complete axiomatization is provided. 1 Keywords: multiagent systems, knowledge, temporal logic, causality, partially ordered sets. 1 Introduction Reasoning about knowledge is one of the fundamental problems in multiagent systems. Usually, dynamic global state spaces partitioned w.r.t. the agents' information are considered [5]. In the theory of distributed systems, knowledge formulas are interpreted over innite linear or branching runs of the systems [8, 9, 5, 13, 20, 21]. It is cle...
Towards Formal Specification and Verification in Cyberspace
 5  7 April 2000, NASA Goddard Space Flight
, 2000
"... A formal framework for specification and verification of multiagent systems is developed. Specification of an infrastructure created by a mobile agent platform is presented. On the basis of the specification, the notions of common ontology core, and agent's knowledge are introduced. A simple a ..."
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Cited by 3 (3 self)
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A formal framework for specification and verification of multiagent systems is developed. Specification of an infrastructure created by a mobile agent platform is presented. On the basis of the specification, the notions of common ontology core, and agent's knowledge are introduced. A simple agent architecture is presented. Given agents' knowledge and decision mechanisms, model checking method is applied to verify whether the agents can realize their goals. 1
Model Checking of Causal Knowledge Formulas
, 1999
"... A model checking algorithm for a variant of the temporal logic of causal knowledge [25] is given. The temporal language is interpreted over labelled prime event structures. Knowledge operators express agents' history knowledge and the knowledge acquired about other agents. The temporal modaliti ..."
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Cited by 2 (0 self)
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A model checking algorithm for a variant of the temporal logic of causal knowledge [25] is given. The temporal language is interpreted over labelled prime event structures. Knowledge operators express agents' history knowledge and the knowledge acquired about other agents. The temporal modalities correspond to the immediate causality and causality. For systems represented by deterministic Asynchronous Automata we prove that the complexity of the model checking algorithm for formula ' over automaton A of Nagents is j'j \Theta jAj \Theta jGA j \Theta 2 O(N 3 logN) , where jGA j is the size of the global state space of A and A is the alphabet of actions. Partial order reductions are used in order to make the model checking algorithm more efficient. 1 Introduction In the theory of distributed systems, knowledge formulas are usually interpreted over infinite linear or branching runs of global states of the systems [12,13,11,16,26,27]. It is clear that capturing changes in state due t...
Local Interactions, Explicit Communication And Causal Knowledge In Games And MultiAgent Systems
"... . In this paper we suggest new structures for modeling games (multiagent systems). We use prime event structures as the branching runs representing all the possible plays in games. Event structures have been already successfully applied in the theory of distributed systems [18] and several temporal ..."
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Cited by 1 (0 self)
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. In this paper we suggest new structures for modeling games (multiagent systems). We use prime event structures as the branching runs representing all the possible plays in games. Event structures have been already successfully applied in the theory of distributed systems [18] and several temporal logics have adopted them as frames. We show that a prime event structure extended with a utility function defined on the terminal nodes can be naturally considered as distributed game in extensive form. The notion of passing knowledge introduces a novel concept to the standard definition of games in extensive form. As well, the notion of information sets (corresponding to agent's knowledge) gets new insight, because now the information sets cannot be defined in an arbitrary way, i.e., they must correspond to causal dependencies in the system. Key words: Multiagent systems, games, even structures, causality, knowledge. 1 Introduction It is intuitively clear that games are closely relat...