The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Jean-loup Guillaume - One of the best experts on this subject based on the ideXlab platform.
-
Temporal Reachability Graphs
2012Co-Authors: John Whitbeck, Vania Conan, Marcelo Dias De Amorim, Jean-loup GuillaumeAbstract:While a natural fit for modeling and understanding mobile networks, time-varying Graphs remain poorly understood. Indeed, many of the usual concepts of static Graphs have no obvious counterpart in time-varying ones. In this paper, we introduce the notion of temporal Reachability Graphs. A (τ, δ)-Reachability Graph is a time-varying directed Graph derived from an existing connectivity Graph. An edge exists from one node to another in the Reachability Graph at time t if there exists a journey (i.e., a spatiotemporal path) in the connectivity Graph from the first node to the second, leaving after t, with a positive edge traversal time τ , and arriving within a maximum delay δ. We make three contributions. First, we develop the theoretical framework around temporal Reachability Graphs. Second, we harness our theoretical findings to propose an algorithm for their efficient computation. Finally, we demonstrate the analytic power of the temporal Reachability Graph concept by applying it to synthetic and real-life datasets. On top of defining clear upper bounds on communication capabilities, Reachability Graphs highlight asymmetric communication opportunities and offloading potential.
-
Temporal Reachability Graphs
arXiv: Networking and Internet Architecture, 2012Co-Authors: John Whitbeck, Marcelo Dias De Amorim, Vania Conan, Jean-loup GuillaumeAbstract:While a natural fit for modeling and understanding mobile networks, time-varying Graphs remain poorly understood. Indeed, many of the usual concepts of static Graphs have no obvious counterpart in time-varying ones. In this paper, we introduce the notion of temporal Reachability Graphs. A (tau,delta)-Reachability Graph} is a time-varying directed Graph derived from an existing connectivity Graph. An edge exists from one node to another in the Reachability Graph at time t if there exists a journey (i.e., a spatiotemporal path) in the connectivity Graph from the first node to the second, leaving after t, with a positive edge traversal time tau, and arriving within a maximum delay delta. We make three contributions. First, we develop the theoretical framework around temporal Reachability Graphs. Second, we harness our theoretical findings to propose an algorithm for their efficient computation. Finally, we demonstrate the analytic power of the temporal Reachability Graph concept by applying it to synthetic and real-life datasets. On top of defining clear upper bounds on communication capabilities, Reachability Graphs highlight asymmetric communication opportunities and offloading potential.
-
MobiCom - Temporal Reachability Graphs
Proceedings of the 18th annual international conference on Mobile computing and networking - Mobicom '12, 2012Co-Authors: John Whitbeck, Marcelo Dias De Amorim, Vania Conan, Jean-loup GuillaumeAbstract:While a natural fit for modeling and understanding mobile networks, time-varying Graphs remain poorly understood. Indeed, many of the usual concepts of static Graphs have no obvious counterpart in time-varying ones. In this paper, we introduce the notion of temporal Reachability Graphs. A (tau,delta)-Reachability Graph is a time-varying directed Graph derived from an existing connectivity Graph. An edge exists from one node to another in the Reachability Graph at time t if there exists a journey (i.e., a spatiotemporal path) in the connectivity Graph from the first node to the second, leaving after t, with a positive edge traversal time tau, and arriving within a maximum delay delta. We make three contributions. First, we develop the theoretical framework around temporal Reachability Graphs. Second, we harness our theoretical findings to propose an algorithm for their efficient computation. Finally, we demonstrate the analytic power of the temporal Reachability Graph concept by applying it to synthetic and real-life datasets. On top of defining clear upper bounds on communication capabilities, Reachability Graphs highlight asymmetric communication opportunities and offloading potential.
John Whitbeck - One of the best experts on this subject based on the ideXlab platform.
-
Temporal Reachability Graphs
2012Co-Authors: John Whitbeck, Vania Conan, Marcelo Dias De Amorim, Jean-loup GuillaumeAbstract:While a natural fit for modeling and understanding mobile networks, time-varying Graphs remain poorly understood. Indeed, many of the usual concepts of static Graphs have no obvious counterpart in time-varying ones. In this paper, we introduce the notion of temporal Reachability Graphs. A (τ, δ)-Reachability Graph is a time-varying directed Graph derived from an existing connectivity Graph. An edge exists from one node to another in the Reachability Graph at time t if there exists a journey (i.e., a spatiotemporal path) in the connectivity Graph from the first node to the second, leaving after t, with a positive edge traversal time τ , and arriving within a maximum delay δ. We make three contributions. First, we develop the theoretical framework around temporal Reachability Graphs. Second, we harness our theoretical findings to propose an algorithm for their efficient computation. Finally, we demonstrate the analytic power of the temporal Reachability Graph concept by applying it to synthetic and real-life datasets. On top of defining clear upper bounds on communication capabilities, Reachability Graphs highlight asymmetric communication opportunities and offloading potential.
-
Temporal Reachability Graphs
arXiv: Networking and Internet Architecture, 2012Co-Authors: John Whitbeck, Marcelo Dias De Amorim, Vania Conan, Jean-loup GuillaumeAbstract:While a natural fit for modeling and understanding mobile networks, time-varying Graphs remain poorly understood. Indeed, many of the usual concepts of static Graphs have no obvious counterpart in time-varying ones. In this paper, we introduce the notion of temporal Reachability Graphs. A (tau,delta)-Reachability Graph} is a time-varying directed Graph derived from an existing connectivity Graph. An edge exists from one node to another in the Reachability Graph at time t if there exists a journey (i.e., a spatiotemporal path) in the connectivity Graph from the first node to the second, leaving after t, with a positive edge traversal time tau, and arriving within a maximum delay delta. We make three contributions. First, we develop the theoretical framework around temporal Reachability Graphs. Second, we harness our theoretical findings to propose an algorithm for their efficient computation. Finally, we demonstrate the analytic power of the temporal Reachability Graph concept by applying it to synthetic and real-life datasets. On top of defining clear upper bounds on communication capabilities, Reachability Graphs highlight asymmetric communication opportunities and offloading potential.
-
MobiCom - Temporal Reachability Graphs
Proceedings of the 18th annual international conference on Mobile computing and networking - Mobicom '12, 2012Co-Authors: John Whitbeck, Marcelo Dias De Amorim, Vania Conan, Jean-loup GuillaumeAbstract:While a natural fit for modeling and understanding mobile networks, time-varying Graphs remain poorly understood. Indeed, many of the usual concepts of static Graphs have no obvious counterpart in time-varying ones. In this paper, we introduce the notion of temporal Reachability Graphs. A (tau,delta)-Reachability Graph is a time-varying directed Graph derived from an existing connectivity Graph. An edge exists from one node to another in the Reachability Graph at time t if there exists a journey (i.e., a spatiotemporal path) in the connectivity Graph from the first node to the second, leaving after t, with a positive edge traversal time tau, and arriving within a maximum delay delta. We make three contributions. First, we develop the theoretical framework around temporal Reachability Graphs. Second, we harness our theoretical findings to propose an algorithm for their efficient computation. Finally, we demonstrate the analytic power of the temporal Reachability Graph concept by applying it to synthetic and real-life datasets. On top of defining clear upper bounds on communication capabilities, Reachability Graphs highlight asymmetric communication opportunities and offloading potential.
R. Zurawski - One of the best experts on this subject based on the ideXlab platform.
-
Scheduling approaches for robotic assembly tasks
Proceedings 1996 IEEE Conference on Emerging Technologies and Factory Automation. ETFA '96, 1Co-Authors: S. Sutdhiraksa, R. ZurawskiAbstract:In this paper, we present an approach to robotic assembly task scheduling which yields suboptimal solutions. The robotic assembly system involves two robot arms working in the same workspace. The collision free operation of the two robot arms is guaranteed by the use of the uniform cell decomposition approach. Timed Petri nets are used to model the assembly activities. The execution times of the assembly activities are determined during the generation of the Reachability Graph. Several approaches used to generate the Reachability Graph and determine the minimum-time paths are proposed.
-
Scheduling robotic assembly tasks using Petri nets
Proceedings of IEEE International Symposium on Industrial Electronics, 1Co-Authors: S. Sutdhiraksa, R. ZurawskiAbstract:In this paper, the authors present an approach to robotic assembly task scheduling which yields suboptimal solutions. The robotic assembly system involves two robots working in the same workspace. Collision between the two robot arms is avoided by the use of the uniform cell decomposition approach. Timed Petri nets are used to model the operations performed by the two robot arms. The execution times of the operations are determined during the generation of the Reachability Graph. Approaches which are used to partially generate the Reachability Graph and determine the minimum-time paths are proposed.
-
Evaluation of scheduling approaches for robotic assembly tasks using Petri nets
Proceedings of the 1996 IEEE IECON. 22nd International Conference on Industrial Electronics Control and Instrumentation, 1Co-Authors: S. Sutdhiraksa, R. ZurawskiAbstract:In this paper, we present an approach to robotic assembly task scheduling which yields suboptimal solutions. The robotic assembly system involves two robot arms working in the same workspace. Collision avoidance between the two robot arms is guaranteed by the use of the uniform cell decomposition approach. Timed Petri nets are used to model the assembly activities. The execution times of the assembly activities are determined during the generation of the Reachability Graph. Several approaches used to generate the Reachability Graph and determine the minimum-time paths are proposed.
Belhassen Zouari - One of the best experts on this subject based on the ideXlab platform.
-
symbolic Reachability Graph and partial symmetries
Applications and Theory of Petri Nets, 1995Co-Authors: Serge Haddad, Jean-michel Ilié, Mohamed Taghelit, Belhassen ZouariAbstract:The construction of symbolic Reachability Graphs is a useful technique for reducing state explosion in High-level Petri nets. Such a reduction is obtained by exploiting the symmetries of the whole net [1]. In this paper, we extend this method to deal with partial symmetries. In a first time, we introduce an example which shows the interest and the principles of our method. Then we develop the general algorithm. Lastly we enumerate the properties of this Extended Symbolic Reachability Graph, including the Reachability equivalence.
-
Application and Theory of Petri Nets - Symbolic Reachability Graph and Partial Symmetries
Lecture Notes in Computer Science, 1995Co-Authors: Serge Haddad, Jean-michel Ilié, Mohamed Taghelit, Belhassen ZouariAbstract:The construction of symbolic Reachability Graphs is a useful technique for reducing state explosion in High-level Petri nets. Such a reduction is obtained by exploiting the symmetries of the whole net [1]. In this paper, we extend this method to deal with partial symmetries. In a first time, we introduce an example which shows the interest and the principles of our method. Then we develop the general algorithm. Lastly we enumerate the properties of this Extended Symbolic Reachability Graph, including the Reachability equivalence.
Harro Wimmel - One of the best experts on this subject based on the ideXlab platform.
-
Optimal Label Splitting for Embedding an LTS into an arbitrary Petri Net Reachability Graph is NP-complete.
arXiv: Computational Complexity, 2020Co-Authors: Uli Schlachter, Harro WimmelAbstract:For a given labelled transition system (LTS), synthesis is the task to find an unlabelled Petri net with an isomorphic Reachability Graph. Even when just demanding an embedding into a Reachability Graph instead of an isomorphism, a solution is not guaranteed. In such a case, label splitting is an option, i.e. relabelling edges of the LTS such that differently labelled edges remain different. With an appropriate label splitting, we can always obtain a solution for the synthesis or embedding problem. Using the label splitting, we can construct a labelled Petri net with the intended bahaviour (e.g. embedding the given LTS in its Reachability Graph). As the labelled Petri net can have a large number of transitions, an optimisation may be desired, limiting the number of labels produced by the label splitting. We show that such a limitation will turn the problem from being solvable in polynomial time into an NP-complete problem.
-
RP - Plain, Bounded, Reversible, Persistent, and k-marked Petri Nets Have Marked Graph Reachability Graphs
Lecture Notes in Computer Science, 2016Co-Authors: Eike Best, Harro WimmelAbstract:In workflow specifications, it is desirable that k customers can use a system interference-freely, so that no customer is disturbed by other activities on the same workflow. In a Petri net representation of a workflow, this corresponds to allowing initial k-markings, in which the number of tokens on each place is a multiple of k, and to require that every global activity is separable, that is, can be viewed as k individual activities, each acting as if the initial marking had one k’th of its values. In this paper, it is shown that, if \(k\ge 2\), if such a Petri net is plain, and if its Reachability Graph is finite, reversible, and persistent, then the latter is isomorphic to the Reachability Graph of a marked Graph.
