22 Result(s)
within
Stefan Dobrev
Computer Science
English
Computer Communication Networks
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Chapter and Conference Paper
Graph Exploration by Energy-Sharing Mobile Agents
We consider the problem of collective exploration of a known n-node edge-weighted graph by k mobile agents that have limited energy but are capable of energy transfers. The agents are initially placed at an arbit...
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Chapter and Conference Paper
Improved Spanners in Networks with Symmetric Directional Antennas
Consider a set \(S\) of sensors in a plane, each equipped with a directional antenna of beamwidth \(\frac{\pi }{2}\) and radius ...
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Chapter and Conference Paper
Complexity of Barrier Coverage with Relocatable Sensors in the Plane
We consider several variations of the problems of covering a set of barriers (modeled as line segments) using sensors that can detect any intruder crossing any of the barriers. Sensors are initially located in...
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Chapter and Conference Paper
Optimal Sensor Networks for Area Monitoring Using Rotating and Beam Sensors
We consider the problem of monitoring the Euclidean plane using rotating sensors with detection sectors and beam sensors. We assume that intruders can appear anywhere at any time and move arbitrarily fast, and...
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Chapter and Conference Paper
Approximating the Edge Length of 2-Edge Connected Planar Geometric Graphs on a Set of Points
Given a set P of n points in the plane, we solve the problems of constructing a geometric planar graph spanning P 1) of minimum degree 2, and 2) which is 2-edge connected, respectively, and has max edge length bo...
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Chapter and Conference Paper
Online Graph Exploration with Advice
We study the problem of exploring an unknown undirected graph with non-negative edge weights. Starting at a distinguished initial vertex s, an agent must visit every vertex of the graph and return to s. Upon visi...
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Chapter and Conference Paper
Asynchronous Exploration of an Unknown Anonymous Dangerous Graph with O(1) Pebbles
We consider the a team of asynchronous agents that must explore an unknown graph in presence of a black hole, a node which destroys all incoming agents without leaving any observable trace. Communication is ac...
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Chapter and Conference Paper
Routing in Carrier-Based Mobile Networks
The past years have seen an intense research effort directed at study of delay/disruption tolerant networks and related concepts (intermittently connected networks, opportunistic mobility networks). As a funda...
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Chapter and Conference Paper
Black Hole Search in Directed Graphs
We consider the problem of cooperative network exploration by agents under the assumption that there is a harmful host present in the network that destroys the incoming agents without outside trace – the so-ca...
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Chapter and Conference Paper
More Efficient Periodic Traversal in Anonymous Undirected Graphs
We consider the problem of periodic graph exploration in which a mobile entity with (at most) constant memory, an agent, has to visit all n nodes of an arbitrary undirected graph G in a periodic manner. Graphs ar...
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Chapter and Conference Paper
Strong Connectivity in Sensor Networks with Given Number of Directional Antennae of Bounded Angle
Given a set S of n sensors in the plane we consider the problem of establishing an ad hoc network from these sensors using directional antennae. We prove that for each given integer 1 ≤ k ≤ 5 there is a strongly ...
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Chapter and Conference Paper
How Much Information about the Future Is Needed?
We propose a new way of characterizing the complexity of online problems. Instead of measuring the degradation of output quality caused by the ignorance of the future we choose to quantify the amount of additi...
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Chapter and Conference Paper
The Power of Tokens: Rendezvous and Symmetry Detection for Two Mobile Agents in a Ring
Rendezvous with detection differs from the usual rendezvous problem in that two mobile agents not only accomplish rendezvous whenever this is possible, but can also detect the impossibility of rendezvous (e.g....
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Chapter and Conference Paper
Local Edge Colouring of Yao-Like Subgraphs of Unit Disk Graphs
The focus of the present paper is on providing a local deterministic algorithm for colouring the edges of Yao-like subgraphs of Unit Disc Graphs. These are geometric graphs such that for some positive integers l,
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Article
Searching for a black hole in arbitrary networks: optimal mobile agents protocols
Consider a networked environment, supporting mobile agents, where there is a black hole: a harmful host that disposes of visiting agents upon their arrival, leaving no observable trace of such a destruction. T...
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Chapter and Conference Paper
Half-Space Proximal: A New Local Test for Extracting a Bounded Dilation Spanner of a Unit Disk Graph
We give a new local test, called a Half-Space Proximal or HSP test, for extracting a sparse directed or undirected subgraph of a given unit disk graph. The HSP neighbors of each vertex are unique, given a fixed u...
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Chapter and Conference Paper
On Fractional Dynamic Faults with Threshold
Unlike localized communication failures that occur on a fixed (although a priori unknown) set of links, dynamic faults can occur on any link. Known also as mobile or ubiquitous faults, their presence makes many t...
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Chapter and Conference Paper
Finding Short Right-Hand-on-the-Wall Walks in Graphs
We consider the problem of perpetual traversal by a single agent in an anonymous undirected graph G. Our requirements are: (1) deterministic algorithm, (2) each node is visited within O(n) moves, (3) the agent us...
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Chapter and Conference Paper
Improved Bounds for Optimal Black Hole Search with a Network Map
A black hole is a harmful host that destroys incoming agents without leaving any observable trace of such a destruction. The black hole search problem is to unambiguously determine the location of the black hole....
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Chapter and Conference Paper
Multiple Agents RendezVous in a Ring in Spite of a Black Hole
The Rendezvous of anonymous mobile agents in a anonymous network is an intensively studied problem; it calls for k anonymous, mobile agents to gather in the same site. We study this problem when in the network th...
