15,448 research outputs found
Sleep scheduling for energy conservation in wireless sensor networks with partial coverage
Cataloged from PDF version of article.Wireless sensor networks, which consist of many sensor devices communicating
with each other in order to sense the environment, is an emerging field in the
area of wireless networking. The primary objective in these wireless networks
is the efficiency of energy consumption. Since these networks consist of a large
number of sensors, allowing some of the nodes to sleep intermittently can greatly
increase the network lifetime. Furthermore, some applications do not require
100% coverage of the network field and allowing the coverage to drop below
100%, i.e., partial coverage, can further increase the network lifetime.
A sleep scheduling algorithm must be distributed, simple, scalable and energy
efficient. In this thesis, the problem of designing such an algorithm which
extends network lifetime while maintaining a target level of partial coverage is
investigated. An algorithm called Distributed Adaptive Sleep Scheduling Algorithm
(DASSA) which does not require location information is proposed. The
performance of DASSA is compared with an integer linear programming (ILP)
based optimum sleep scheduling algorithm, an oblivious algorithm and with an
existing algorithm in the literature. DASSA attains network lifetimes up to 89%
of the optimum solution, and it achieves significantly longer lifetimes compared
with the other two algorithms.
Furthermore, the minimum number of sensors that should be deployed in
order to satisfy a given partial coverage target with a certain probability while
maintaining connectivity is computed and an ILP formulation is presented for
finding the minimum number of sensors that should be activated within the set
of deployed sensors.Yardibi, TarıkM.S
A Coverage Monitoring algorithm based on Learning Automata for Wireless Sensor Networks
To cover a set of targets with known locations within an area with limited or
prohibited ground access using a wireless sensor network, one approach is to
deploy the sensors remotely, from an aircraft. In this approach, the lack of
precise sensor placement is compensated by redundant de-ployment of sensor
nodes. This redundancy can also be used for extending the lifetime of the
network, if a proper scheduling mechanism is available for scheduling the
active and sleep times of sensor nodes in such a way that each node is in
active mode only if it is required to. In this pa-per, we propose an efficient
scheduling method based on learning automata and we called it LAML, in which
each node is equipped with a learning automaton, which helps the node to select
its proper state (active or sleep), at any given time. To study the performance
of the proposed method, computer simulations are conducted. Results of these
simulations show that the pro-posed scheduling method can better prolong the
lifetime of the network in comparison to similar existing method
Markov Decision Processes with Applications in Wireless Sensor Networks: A Survey
Wireless sensor networks (WSNs) consist of autonomous and resource-limited
devices. The devices cooperate to monitor one or more physical phenomena within
an area of interest. WSNs operate as stochastic systems because of randomness
in the monitored environments. For long service time and low maintenance cost,
WSNs require adaptive and robust methods to address data exchange, topology
formulation, resource and power optimization, sensing coverage and object
detection, and security challenges. In these problems, sensor nodes are to make
optimized decisions from a set of accessible strategies to achieve design
goals. This survey reviews numerous applications of the Markov decision process
(MDP) framework, a powerful decision-making tool to develop adaptive algorithms
and protocols for WSNs. Furthermore, various solution methods are discussed and
compared to serve as a guide for using MDPs in WSNs
Locating sensors with fuzzy logic algorithms
In a system formed by hundreds of sensors deployed
in a huge area it is important to know the position where every
sensor is.
This information can be obtained using several methods.
However, if the number of sensors is high and the deployment
is based on ad-hoc manner, some auto-locating techniques must
be implemented.
In this paper we describe a novel algorithm based on fuzzy
logic with the objective of estimating the location of sensors
according to the knowledge of the position of some reference
nodes.
This algorithm, called LIS (Localization based on Intelligent
Sensors) is executed distributively along a wireless sensor network
formed by hundreds of nodes, covering a huge area.
The evaluation of LIS is led by simulation tests. The result
obtained shows that LIS is a promising method that can easily
solve the problem of knowing where the sensors are located.Junta de AndalucÃa P07-TIC-0247
Design of Combined Coverage Area Reporting and Geo-casting of Queries for Wireless Sensor Networks
In order to efficiently deal with queries or other location dependent information, it is key that the wireless sensor network informs gateways what geographical area is serviced by which gateway. The gateways are then able to e.g. efficiently route queries which are only valid in particular regions of the deployment. The proposed algorithms combine coverage area reporting and geographical routing of queries which are injected by gateways.\u
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