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22
Dynamic Shortest Paths Containers
, 2003
"... Using a set of geometric containers to speed up shortest path queries in a weighted graph has been proven a useful tool for dealing with large sparse graphs. Given a layout of a graph G = (V, E), we store, for each edge (u, v) E, the bounding box of all nodes t V for which a shortest utpath ..."
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Cited by 8 (3 self)
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Using a set of geometric containers to speed up shortest path queries in a weighted graph has been proven a useful tool for dealing with large sparse graphs. Given a layout of a graph G = (V, E), we store, for each edge (u, v) E, the bounding box of all nodes t V for which a shortest utpath starts with (u, v). Shortest path queries can then be answered by Dijkstra's algorithm restricted to edges where the corresponding bounding box contains the target. In this
Fully Dynamic Planarity Testing with Applications
"... The fully dynamic planarity testing problem consists of performing an arbitrary sequence of the following three kinds of operations on a planar graph G: (i) insert an edge if the resultant graph remains planar; (ii) delete an edge; and (iii) test whether an edge could be added to the graph without ..."
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Cited by 6 (0 self)
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The fully dynamic planarity testing problem consists of performing an arbitrary sequence of the following three kinds of operations on a planar graph G: (i) insert an edge if the resultant graph remains planar; (ii) delete an edge; and (iii) test whether an edge could be added to the graph without violating planarity. We show how to support each of the above operations in O(n2=3) time, where n is the number of vertices in the graph. The bound for tests and deletions is worstcase, while the bound for insertions is amortized. This is the first algorithm for this problem with sublinear running time, and it affirmatively answers a question posed in [11]. The same data structure has further applications in maintaining the biconnected and triconnected components of a dynamic planar graph. The time bounds are the same: O(n2=3) worstcase time per edge deletion, O(n2=3) amortized time per edge insertion, and O(n2=3) worstcase time to check whether two vertices are either biconnected or triconnected.
A Practical Temporal Constraint Management System for RealTime Applications
"... Abstract. A temporal constraint management system (TCMS) is a temporal network together with algorithms for managing the constraints in that network over time. This paper presents a practical TCMS, called MYSYSTEM, that efficiently handles the propagation of the kinds of temporal constraints commonl ..."
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Abstract. A temporal constraint management system (TCMS) is a temporal network together with algorithms for managing the constraints in that network over time. This paper presents a practical TCMS, called MYSYSTEM, that efficiently handles the propagation of the kinds of temporal constraints commonly found in realtime applications, while providing constanttime access to “allpairs, shortestpath ” information that is extremely useful in many applications. The temporal network in MYSYSTEM includes special timepoints for dealing with the passage of time and eliminating the need for certain common forms of constraint propagation. The constraint propagation algorithm in MYSYSTEM maintains a restricted set of entries in the associated allpairs, shortestpath matrix by incrementally propagating changes to the network either from adding a new constraint or strengthening, weakening or deleting an existing constraint. The paper presents empirical evidence to support the claim that MYSYSTEM is scalable to realtime planning, scheduling and acting applications. 1
Geometric Shortest Path Containers
, 2004
"... In this paper, we consider Dijkstra's algorithm for the single source single target shortest path problem in large sparse graphs. The goal is to reduce the response time for online queries by using precomputed information. Due to the size of the graph, preprocessing space requirements can b ..."
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Cited by 2 (1 self)
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In this paper, we consider Dijkstra's algorithm for the single source single target shortest path problem in large sparse graphs. The goal is to reduce the response time for online queries by using precomputed information. Due to the size of the graph, preprocessing space requirements can be only linear in the number of nodes. We assume that a layout of the graph is given. In the preprocessing, we determine from this layout a geometric object for each edge containing all nodes that can be reached by a shortest path starting with that edge.
Dynamic Controllability of STNUs • 2 • Luke Hunsberger•
, 2013
"... Agent controlling remote spacecraft Fleets of autonomous spacecraft Business manufacturing processes Medical treatment processes ⇒ Temporal constraints among actions ⇒ Actions with uncertain durations ..."
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Agent controlling remote spacecraft Fleets of autonomous spacecraft Business manufacturing processes Medical treatment processes ⇒ Temporal constraints among actions ⇒ Actions with uncertain durations
Performance and Functionality in Overlay Networks by
, 2004
"... Overlay networks create virtual topologies on top of the existing networking infrastructure and come as a middle layer between enduser applications and the basic network services. The main reasons of using an intermediate level of communication are the new service functionality and the improved per ..."
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Overlay networks create virtual topologies on top of the existing networking infrastructure and come as a middle layer between enduser applications and the basic network services. The main reasons of using an intermediate level of communication are the new service functionality and the improved performance offered by application specific protocols that can be deployed in overlay networks. This thesis explores the benefits offered by overlay networks and introduces new mechanisms that improve performance and offer additional functionality to networking applications. Multicast services are rarely used today, mainly due to scalability and security concerns. An overlay architecture addresses these issues by moving the service management and deployment above the network infrastructure. We present an architecture for transparent overlay multicast and an optimal distributed flow control for reliable multicast in overlay networks that scales with the number of participants and groups. Even though capacity grows exponentially over time, latency is difficult to improve. We present an overlay approach that can substantially decrease the number of delayed packets in wide area reliable communication and increase the delivery ratio of best effort communication, leading to improved performance in timesensitive applications such as Voice over IP.
Average Case Analysis of Fully Dynamic Reachability for Directed Graphs
"... We consider the problem of maintaining the transitive closure in a directed graph under edge insertions and deletions from the point of view of average case analysis. Say n the number of nodes and m the number of edges. We present a data structure that supports the report of a path between two no ..."
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We consider the problem of maintaining the transitive closure in a directed graph under edge insertions and deletions from the point of view of average case analysis. Say n the number of nodes and m the number of edges. We present a data structure that supports the report of a path between two nodes in O(n \Delta log n) expected time and O(1) amortized time per update, and reachability queries in O(1) expected time and O(n \Delta log n) expected amortized time per update. If m ? n then reachability queries can be performed in O(1) expected time and O(log n) expected amortized time per update. These bounds compares favorably with the best bounds known using worst case analysis.
Date Author's
, 2005
"... Author's declaration Aware of legal responsibility I hereby declare that I have written this dissertation myself and all the contents of the dissertation have been obtained by legal means. ..."
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Author's declaration Aware of legal responsibility I hereby declare that I have written this dissertation myself and all the contents of the dissertation have been obtained by legal means.