70,816 research outputs found
Connectivity-guaranteed and obstacle-adaptive deployment schemes for mobile sensor networks
Mobile sensors can relocate and self-deploy into a network. While focusing on the problems of coverage, existing deployment schemes largely over-simplify the conditions for network connectivity: they either assume that the communication range is large enough for sensors in geometric neighborhoods to obtain location information through local communication, or they assume a dense network that remains connected. In addition, an obstacle-free field or full knowledge of the field layout is often assumed. We present new schemes that are not governed by these assumptions, and thus adapt to a wider range of application scenarios. The schemes are designed to maximize sensing coverage and also guarantee connectivity for a network with arbitrary sensor communication/sensing ranges or node densities, at the cost of a small moving distance. The schemes do not need any knowledge of the field layout, which can be irregular and have obstacles/holes of arbitrary shape. Our first scheme is an enhanced form of the traditional virtual-force-based method, which we term the Connectivity-Preserved Virtual Force (CPVF) scheme. We show that the localized communication, which is the very reason for its simplicity, results in poor coverage in certain cases. We then describe a Floor-based scheme which overcomes the difficulties of CPVF and, as a result, significantly outperforms it and other state-of-the-art approaches. Throughout the paper our conclusions are corroborated by the results from extensive simulations
Optimal coverage multi-path scheduling scheme with multiple mobile sinks for WSNs
Wireless Sensor Networks (WSNs) are usually formed with many tiny sensors which are randomly deployed within sensing field for target monitoring. These sensors can transmit their monitored data to the sink in a multi-hop communication manner. However, the ‘hot spots’ problem will be caused since nodes near sink will consume more energy during forwarding. Recently, mobile sink based technology provides an alternative solution for the long-distance communication and sensor nodes only need to use single hop communication to the mobile sink during data transmission. Even though it is difficult to consider many network metrics such as sensor position, residual energy and coverage rate etc., it is still very important to schedule a reasonable moving trajectory for the mobile sink. In this paper, a novel trajectory scheduling method based on coverage rate for multiple mobile sinks (TSCR-M) is presented especially for large-scale WSNs. An improved particle swarm optimization (PSO) combined with mutation operator is introduced to search the parking positions with optimal coverage rate. Then the genetic algorithm (GA) is adopted to schedule the moving trajectory for multiple mobile sinks. Extensive simulations are performed to validate the performance of our proposed method
Trajectory Aware Macro-cell Planning for Mobile Users
We design and evaluate algorithms for efficient user-mobility driven
macro-cell planning in cellular networks. As cellular networks embrace
heterogeneous technologies (including long range 3G/4G and short range WiFi,
Femto-cells, etc.), most traffic generated by static users gets absorbed by the
short-range technologies, thereby increasingly leaving mobile user traffic to
macro-cells. To this end, we consider a novel approach that factors in the
trajectories of mobile users as well as the impact of city geographies and
their associated road networks for macro-cell planning. Given a budget k of
base-stations that can be upgraded, our approach selects a deployment that
impacts the most number of user trajectories. The generic formulation
incorporates the notion of quality of service of a user trajectory as a
parameter to allow different application-specific requirements, and operator
choices.We show that the proposed trajectory utility maximization problem is
NP-hard, and design multiple heuristics. We evaluate our algorithms with real
and synthetic data sets emulating different city geographies to demonstrate
their efficacy. For instance, with an upgrade budget k of 20%, our algorithms
perform 3-8 times better in improving the user quality of service on
trajectories in different city geographies when compared to greedy
location-based base-station upgrades.Comment: Published in INFOCOM 201
Towards Monocular Vision based Obstacle Avoidance through Deep Reinforcement Learning
Obstacle avoidance is a fundamental requirement for autonomous robots which
operate in, and interact with, the real world. When perception is limited to
monocular vision avoiding collision becomes significantly more challenging due
to the lack of 3D information. Conventional path planners for obstacle
avoidance require tuning a number of parameters and do not have the ability to
directly benefit from large datasets and continuous use. In this paper, a
dueling architecture based deep double-Q network (D3QN) is proposed for
obstacle avoidance, using only monocular RGB vision. Based on the dueling and
double-Q mechanisms, D3QN can efficiently learn how to avoid obstacles in a
simulator even with very noisy depth information predicted from RGB image.
Extensive experiments show that D3QN enables twofold acceleration on learning
compared with a normal deep Q network and the models trained solely in virtual
environments can be directly transferred to real robots, generalizing well to
various new environments with previously unseen dynamic objects.Comment: Accepted by RSS 2017 workshop New Frontiers for Deep Learning in
Robotic
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