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ScienceDirect Procedia Engineering 87 (2014) 524 – 527
EUROSENSORS 2014, the XXVIII edition of the conference series
Wireless Sensor Network for Environmental Monitoring with 3G Connectivity Thomas Posnicek*, Karlheinz Kellner, Martin Brandl Center for Integrated Sensor Systems, Danube University Krems, 3500 Krems, Austria
Abstract Today wireless sensor networks gain more and more relevance in measuring and recording of various physical or chemical parameters. For an independent a flexible operation all sensor nodes are equipped with batteries. All sensor nodes together are building a self-sustaining wireless network and directing all measured data via an on-demand routing algorithm to the base station. A source driven, data centric on-demand routing protocol was developed [1] for an efficient transmission of data sets via the network in direction of the base station. The routing protocol is based on the local attractiveness of each sensor node where for the next hop the neighboring node with the highest attractiveness will be chosen. The attractiveness of each node is calculated from several parameters like the distance to the base station, the actual energy etc. All data sets are transmitted via multiple hops in direction of increasing attractiveness where the base station is set to the highest value. The base station collects all data sets and enables a transmission via a mobile data connection (3G) to a server. By a smartphone the data sets can be easily accessed and displayed. © byby Elsevier Ltd.Ltd. This is an open access article under the CC BY-NC-ND license © 2014 2014The TheAuthors. Authors.Published Published Elsevier (http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the scientific committee of Eurosensors 2014. Peer-review under responsibility of the scientific committee of Eurosensors 2014 Keywords: Wireless sensor network; environmental monitoring
1. Introduction Attractiveness based -routing is a source-initiated on-demand routing mechanism which considers the actual energy states of neighbor nodes for the routing decision and therefore ensures energy aware operation. The hierarchy is flat.
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1877-7058 © 2014 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license
(http://creativecommons.org/licenses/by-nc-nd/3.0/). Peer-review under responsibility of the scientific committee of Eurosensors 2014 doi:10.1016/j.proeng.2014.11.539
Thomas Posnicek et al. / Procedia Engineering 87 (2014) 524 – 527
Some other protocols use a hierarchical topology, which means they form groups for the purpose of communication. On-demand routing creates routes only when desired by the source node. When a node requires a route to a destination, it initiates a route discovery process within the network by choosing the next hop node by the highest node attractiveness-level. To start a route discovery, or any other communication, all neighbors must first be synchronized. This means that all communicating nodes need one common active time, which can be used for communication. The rest of the time the nodes are in a low power mode (sleep mode). Every node periodically wakes up to communicate with its neighbors, and then goes back to sleep until the next frame. Meanwhile, new messages are queued. After the synchronization process, the node updates its attractiveness-level by choosing the highest received attractiveness-level from the neighbor nodes and calculates its own attractiveness-level by the routing algorithm [1]. 2. Routing Fig. 1 shows an example about the routing principle where node 4 requests a routing decision. The routing decision is done by evaluating the neighbor’s attractiveness level which is influenced by all nodes of the path (Fig. 1a-c).
Fig. 1: Example of next hop decision. The energy of the nodes influence the pheromone/ attractiveness level of the nodes and its neighbors.
3. Results In Fig. 2 a practical application of the wireless network in the field of environmental monitoring is presented. To test the long term stability and the performance of the attractiveness based routing algorithm, we placed several nodes for local temperature and humidity monitoring in wine yards. The downy mildew fungi plasmopara viticola is one of the most problematic infections in wine yards and can conclude in a total loss of wine grapes. The growth of downy mildew is manly given at temperatures and humidity’s where the dew point (humidity is 100%) is reached but this can be locally very different and makes therefore the preventive application of fungicides very difficult. The sensor network can help the farmers to detect the regions in which the growth of downy mildew has high probability and makes a local application of fungicides necessary.
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Thomas Posnicek et al. / Procedia Engineering 87 (2014) 524 – 527
Fig. 2: a) Base Station; b) Downy mildew infection on grapes, c) User interface for measured data
All system simulations were done in NetLogo, a multi-agent cross-platform modeling- and simulationenvironment for simulating complex systems over time (Fig. 3).
Fig. 3: Simulations were done in the multi-agent simulation environment NetLogo. The simulation tool offers an easy to design graphical user interface comprising action buttons, sliders for the adjustment of variables, a simulation window where the turtles (nodes) are randomly placed and numerical and graphical windows representing the output variables. The used simulation tool is open to compare the performance of different routing algorithms in complex scenarios.
Thomas Posnicek et al. / Procedia Engineering 87 (2014) 524 – 527
Acknowledgements The authors would like to thank the government of Lower Austria and the European Commission (EFRE) for financially supporting the project (WST3-T-91/026-2013). References [1] Brandl M, Kos A, Kellner K, Mayerhofer C, Posnicek T, Fabian C: A Source Based On-Demand Data Forwarding Scheme for Wireless Sensor Networks. International Journal of Wireless Networks and Broadband Technologies, 2011;1(3):49-70.
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