Results 1 
5 of
5
Hierarchical Visibility for Guaranteed Search in LargeScale Outdoor Terrain
 AUTONOMOUS AGENTS AND MULTIAGENT SYSTEMS
"... ..."
Solving PursuitEvasion Problems on Height Maps
"... Abstract — In this paper we present an approach for a pursuitevasion problem that considers a 2.5d environment represented by a height map. Such a representation is particularly suitable for largescale outdoor pursuitevasion. By allowing height information we not only capture some aspects of 3d v ..."
Abstract

Cited by 4 (0 self)
 Add to MetaCart
(Show Context)
Abstract — In this paper we present an approach for a pursuitevasion problem that considers a 2.5d environment represented by a height map. Such a representation is particularly suitable for largescale outdoor pursuitevasion. By allowing height information we not only capture some aspects of 3d visibility but can also consider target heights. In our approach we construct a graph representation of the environment by sampling points and their detection sets which extend the usual notion of visibility. Once a graph is constructed we compute strategies on this graph using a modification of previous work on graphsearching. This strategy is converted into robot paths that are planned on the height map by classifying the terrain appropriately. In experiments we investigate the performance of our approach and provide examples including a map of a small village with surrounding hills and a sample map with multiple loops and elevation plateaus. Experiments are carried out with varying sensing ranges as well as target and sensor heights. To the best of our knowledge the presented approach is the first viable solution to 2.5d pursuitevasion with height maps. I.
Connected searching of weighted trees
"... In this paper we consider the problem of connected edge searching of weighted trees. Barrière et al. claim in [Capture of an intruder by mobile agents, SPAA’02 (2002) 200209] that there exists a polynomialtime algorithm for finding an optimal search strategy, that is, a strategy that minimizes th ..."
Abstract
 Add to MetaCart
(Show Context)
In this paper we consider the problem of connected edge searching of weighted trees. Barrière et al. claim in [Capture of an intruder by mobile agents, SPAA’02 (2002) 200209] that there exists a polynomialtime algorithm for finding an optimal search strategy, that is, a strategy that minimizes the number of used searchers. However, due to some flaws in their algorithm, the problem turns out to be open. It is proven in this paper that the considered problem is strongly NPcomplete even for nodeweighted trees (the weight of each edge is 1) with one vertex of degree greater than 2. It is also shown that there exists a polynomialtime algorithm for finding an optimal connected search strategy for a given bounded degree tree with arbitrary weights on the edges and on the vertices. This is an FPT algorithm with respect to the maximum degree of a tree.
Solving Pursuitevasion Problems with GraphClear: an Overview
"... Abstract—This paper presents an overview of the numerous results we recently published for the problem of multirobot pursuit evasion. We review the GraphClear formalism we introduced, we summarize the variants we studied, and the main results we derived. Finally, we outline directions for future r ..."
Abstract
 Add to MetaCart
(Show Context)
Abstract—This paper presents an overview of the numerous results we recently published for the problem of multirobot pursuit evasion. We review the GraphClear formalism we introduced, we summarize the variants we studied, and the main results we derived. Finally, we outline directions for future research both in GraphClear and for pursuitevasion and search problems in general. I.
Editorial Manager(tm) for Journal of Autonomous Agents and MultiAgent Systems Manuscript Draft Manuscript Number: Title: Hierarchical Visibility for Guaranteed Search in LargeScale Outdoor Terrain Article Type: Manuscript
"... To search for moving targets in a large area is a challenging task that is relevant in several problem domains, such as capturing an invader in a camp, guarding security facilities, and searching for victims in largescale search and rescue scenarios. The guaranteed search problem is to coordinate t ..."
Abstract
 Add to MetaCart
(Show Context)
To search for moving targets in a large area is a challenging task that is relevant in several problem domains, such as capturing an invader in a camp, guarding security facilities, and searching for victims in largescale search and rescue scenarios. The guaranteed search problem is to coordinate the search of a team of agents in a way that all targets are guaranteed to be found. In this paper we present a selfcontained solution to this problem in threedimensional realworld domains represented by digital elevation models (DEMs). We introduce hierarchical sampling on DEMs for selecting strategical valuable locations from which larger parts of the map are visible. These locations are utilized to form a search graph from which search schedules are deduced, and agent paths that are directly executable in the terrain, are computed. Presented experimental results indicate that the proposed method leads to schedules requiring a significantly low number of agents for the search. The practical feasibility of our approach has been validated during a field experiment at the Gascola robot training site, where teams of humans equipped with IPads successfully searched for adversarial and omniscient evaders.