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...ots, sensor network. I. INTRODUCTION THE COVERAGE problem has been defined [3] as the maximization of the total area covered by robot’s sensors. The static coverage problem is addressed by algorithms =-=[4]-=-–[6] which are designed to deploy robot(s) in a static configuration, such that every point in the environment is under the robots’ sensor shadow (i.e., covered) at every instant of time. For complete...

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...nsing and local interactions between the robot and the sensor network. The problem of coverage and deployment in the sensor network community was considered from a different perspective. For example, =-=[21]-=- considers quality of service of the deployed network, [22] discusses algorithms to achieve low energy deployment. Collaborative target tracking and surveillance is considered in [23] and [24]. Algori...

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... is analyzed to locate the “frontiers” between the free and unknown space. Exploration proceeds in the direction of the closest “frontier.” The multirobot version of the same problem was addressed in =-=[11]-=-. Our algorithm differs from these approaches in a number of ways. We use neither a map, nor localization in a shared frame of reference. Our algorithm is based on the deployment of static, communicat...

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... obstacle on its way. DeployBeacon behavior forces the robot to deploy a new node, which becomes a current node for the robot. VII. SIMULATION EXPERIMENTS In our experiments, we used the Player/Stage =-=[29]-=-, [30] simulation engine populated with a simulated Pioneer 2DX mobile robot equipped with two 180 field-of-view planar laser range finders positioned back-to-back (equivalent to a 2-D omnidirectional...

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...t), followed by the directions with least last update value (least value of C). Note that this algorithm does not use inter-node communication. The robot is programmed using a behavior-based approach =-=[27]-=- with arbitration [28] for behavior coordination. Priorities are assigned to every behavior a priori. As shown in Fig. 15, the robot executes four behaviors: ObstacleAvoidance, AtBeacon, DeployBeacon,...

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... approximated by a grid of equally spaced cells, and exact decomposition, where the free space is exactly partitioned. Exploration, a problem closely related to coverage, has been extensively studied =-=[9]-=-, [10]. The frontier-based approach [9] concerns itself with incrementally constructing a global occupancy map of the environment. The map is analyzed to locate the “frontiers” between the free and un...

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...scuss the implementation of LRV in simulation and in real hardware. Index Terms—Coverage, deployment, exploration, mobile robots, sensor network. I. INTRODUCTION THE COVERAGE problem has been defined =-=[3]-=- as the maximization of the total area covered by robot’s sensors. The static coverage problem is addressed by algorithms [4]–[6] which are designed to deploy robot(s) in a static configuration, such ...

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...or network. The problem of coverage and deployment in the sensor network community was considered from a different perspective. For example, [21] considers quality of service of the deployed network, =-=[22]-=- discusses algorithms to achieve low energy deployment. Collaborative target tracking and surveillance is considered in [23] and [24]. Algorithm 1 Least Recently Visited (LRV) Algorithm—Robot Loop —cu...

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...overage and exploration algorithm, not an entity used by the algorithm itself. qThe problem of exploration using passive nodes (READ-only devices) was considered from the graph theoretic viewpoint in =-=[12]-=- and [13]. In both cases the authors studied the problem of dynamic single robot coverage on a graph world. The key result was that the ability to tag a limited number of vertices (in some cases, only...

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...ve. For example, [21] considers quality of service of the deployed network, [22] discusses algorithms to achieve low energy deployment. Collaborative target tracking and surveillance is considered in =-=[23]-=- and [24]. Algorithm 1 Least Recently Visited (LRV) Algorithm—Robot Loop —current node and suggested direction; —set containing data received from nodes in robot’s vicinity (node id, signal strength, ...

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...xample, [21] considers quality of service of the deployed network, [22] discusses algorithms to achieve low energy deployment. Collaborative target tracking and surveillance is considered in [23] and =-=[24]-=-. Algorithm 1 Least Recently Visited (LRV) Algorithm—Robot Loop —current node and suggested direction; —set containing data received from nodes in robot’s vicinity (node id, signal strength, suggested...

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...simulation examples of LRV when an obstacle avoidance is used in the deployment cycle. An environment used in this section was also used in a more elaborate series of experiments with LRV reported in =-=[31]-=- that modify the environment in the real time, while the robot is successfully executing coverage and exploration tasks. VIII. IMPLICIT SENSOR NETWORK REPAIR AND MAINTENANCE An emergent property of LR...

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... sensor network. I. INTRODUCTION THE COVERAGE problem has been defined [3] as the maximization of the total area covered by robot’s sensors. The static coverage problem is addressed by algorithms [4]–=-=[6]-=- which are designed to deploy robot(s) in a static configuration, such that every point in the environment is under the robots’ sensor shadow (i.e., covered) at every instant of time. For complete sta...

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...oximated by a grid of equally spaced cells, and exact decomposition, where the free space is exactly partitioned. Exploration, a problem closely related to coverage, has been extensively studied [9], =-=[10]-=-. The frontier-based approach [9] concerns itself with incrementally constructing a global occupancy map of the environment. The map is analyzed to locate the “frontiers” between the free and unknown ...

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...in order to observe all points in the environment frequently. In other words, we address the dynamic coverage problem with a single robot. A recent survey of coverage algorithms is provided by Choset =-=[8]-=-. This survey distinguishes between online algorithms, in which the map of the environment is not available a priori, and offline algorithms, in which the map is available (hence, an optimal assignmen...

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...nor communicate. 4) We do not assume that nodes need to be retrieved; in [12] and [13], retrieval and reuse of nodes by the robot is implied. Our paper is closely related to the ant robots literature =-=[14]-=-–[20], where the idea of a node with decaying intensity (a semi-active node) is used. The robots sense the change in intensity and are able to change the direction of exploration to cover environment ...

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... work was supported in part by the National Science Foundation under Grant ANI-0082498, Grant IIS-0133947, Grant EIA-0121141, and Grant CCR-0120778. Portions of this paper have appeared previously in =-=[1]-=- and [2]. The authors are with the University of California, Los Angeles, CA 90095 USA (e-mail: maxim@cens.ucla.edu) and the University of Southern California, Los Angeles, CA 90089 USA (e-mail: gaura...

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...unknown a priori. Dynamic coverage, on the other hand, is addressed by algorithms which explore and hence “cover” the environment with constant motion and neither settle to a particular configuration =-=[7]-=-, nor necessarily to a particular pattern of traversal. Manuscript received December 14, 2005; revised October 6, 2006. This paper was recommended for publication by Associate Editor J. Wen and Editor...

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...s supported in part by the National Science Foundation under Grant ANI-0082498, Grant IIS-0133947, Grant EIA-0121141, and Grant CCR-0120778. Portions of this paper have appeared previously in [1] and =-=[2]-=-. The authors are with the University of California, Los Angeles, CA 90095 USA (e-mail: maxim@cens.ucla.edu) and the University of Southern California, Los Angeles, CA 90089 USA (e-mail: gaurav@usc.ed...

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...ommunicate. 4) We do not assume that nodes need to be retrieved; in [12] and [13], retrieval and reuse of nodes by the robot is implied. Our paper is closely related to the ant robots literature [14]–=-=[20]-=-, where the idea of a node with decaying intensity (a semi-active node) is used. The robots sense the change in intensity and are able to change the direction of exploration to cover environment effic...

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...g performance metrics. Definition (Coverage on a Graph) 1: Coverage on a graph is the act of visiting every vertex of a graph. The performance of a coverage algorithm is measured using the cover time =-=[25]-=- defined as follows. Definition (Cover Time) 2: Cover time is the number of edges traversed such that every vertex of a graph is visited at least once, i.e., the graph is covered. In order to cover a ...

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...ver time achieved by our algorithm is clearly better. However, if the nodes are a precious resource, the algorithm described in [12] would be preferred. Another algorithm we compare LRV to is 1-LRTA* =-=[26]-=-. 1-LRTA* is a well known graph search algorithm that can be applied to graph coverage. Algorithm 4 shows the details of 1-LRTA*. In 1-LRTA*, a weight is associated with a node. The edge to traverse i...

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...rections with least last update value (least value of C). Note that this algorithm does not use inter-node communication. The robot is programmed using a behavior-based approach [27] with arbitration =-=[28]-=- for behavior coordination. Priorities are assigned to every behavior a priori. As shown in Fig. 15, the robot executes four behaviors: ObstacleAvoidance, AtBeacon, DeployBeacon, and SearchBeacon. In ...

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...cle on its way. DeployBeacon behavior forces the robot to deploy a new node, which becomes a current node for the robot. VII. SIMULATION EXPERIMENTS In our experiments, we used the Player/Stage [29], =-=[30]-=- simulation engine populated with a simulated Pioneer 2DX mobile robot equipped with two 180 field-of-view planar laser range finders positioned back-to-back (equivalent to a 2-D omnidirectional laser...