1,481 research outputs found

    Coverage Protocols for Wireless Sensor Networks: Review and Future Directions

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    The coverage problem in wireless sensor networks (WSNs) can be generally defined as a measure of how effectively a network field is monitored by its sensor nodes. This problem has attracted a lot of interest over the years and as a result, many coverage protocols were proposed. In this survey, we first propose a taxonomy for classifying coverage protocols in WSNs. Then, we classify the coverage protocols into three categories (i.e. coverage aware deployment protocols, sleep scheduling protocols for flat networks, and cluster-based sleep scheduling protocols) based on the network stage where the coverage is optimized. For each category, relevant protocols are thoroughly reviewed and classified based on the adopted coverage techniques. Finally, we discuss open issues (and recommend future directions to resolve them) associated with the design of realistic coverage protocols. Issues such as realistic sensing models, realistic energy consumption models, realistic connectivity models and sensor localization are covered

    On the design of smart parking networks in the smart cities: an optimal sensor placement model

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    Smart parking is a typical IoT application that can benefit from advances in sensor, actuator and RFID technologies to provide many services to its users and parking owners of a smart city. This paper considers a smart parking infrastructure where sensors are laid down on the parking spots to detect car presence and RFID readers are embedded into parking gates to identify cars and help in the billing of the smart parking. Both types of devices are endowed with wired and wireless communication capabilities for reporting to a gateway where the situation recognition is performed. The sensor devices are tasked to play one of the three roles: (1) slave sensor nodes located on the parking spot to detect car presence/absence; (2) master nodes located at one of the edges of a parking lot to detect presence and collect the sensor readings from the slave nodes; and (3) repeater sensor nodes, also called ''anchor'' nodes, located strategically at specific locations in the parking lot to increase the coverage and connectivity of the wireless sensor network. While slave and master nodes are placed based on geographic constraints, the optimal placement of the relay/anchor sensor nodes in smart parking is an important parameter upon which the cost and e ciency of the parking system depends. We formulate the optimal placement of sensors in smart parking as an integer linear programming multi-objective problem optimizing the sensor network engineering e ciency in terms of coverage and lifetime maximization, as well as its economic gain in terms of the number of sensors deployed for a specific coverage and lifetime. We propose an exact solution to the node placement problem using single-step and two-step solutions implemented in the Mosel language based on the Xpress-MPsuite of libraries. Experimental results reveal the relative e ciency of the single-step compared to the two-step model on di erent performance parameters. These results are consolidated by simulation results, which reveal that our solution outperforms a random placement in terms of both energy consumption, delay and throughput achieved by a smart parking network

    PERFORMANCE & SIMULATION ANALYSIS OF SENSOR AREA COVERAGE

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    Wireless sensor networks (WSNs) have been employed in numerous military and civilian applications. Some application areas are in battlefield, surveillance, biological detection, and environmental monitoring. A major challenge to such applications is the sensor areacoverage (SAC), which refers to the techniques and mechanisms of placing sensors and their coordination in a mission space (field) to monitor the physical environment in such a way to achieve the application coverage objectives. This thesis develops a sensor area coverage package (SACPac) that simulates some selected coverage algorithms and their enhancements, and analyzes their performance parameters under various scenarios. The performance parameters considered include coverage ratio, resiliency of the field coverage against sensor failures, energy efficiency, and security of communication among sensors. The thesis also develops a prototype of communication for sending the position of an object via a mobile device to the server on which SACPac runs, so that the object trajectory can be displayed. SACPac provides the foundation for further enhancements and future research. It can also be used as an educational tool for those interested in the SAC problem

    Strategies for coverage and focus on event for robotic swarms with limited sensing capabilities

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    We consider the problem of coverage in Robotic Networks: developing an efficient algorithm which is able to perform a deployment in static-obstacle-structured environments focusing on events is our main idea. We are interested on the trade-off between local communication and optimal coverage, therefore we are going to present an algorithm based on article: "Sensor Coverage Robot Swarms Using Local Sensing without Metric Information", using its similar scenario types

    Effiziente Lokalisierung von Nutzern und Geräten in Smarten Umgebungen

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    The thesis considers determination of location of sensors and users in smart environments using measurements of Received Signal Strength (RSS). The first part of the thesis focuses on localization in Wireless Sensor Networks and contributes two fully distributed algorithms which address the Sensor Selection Problem and provide the best trade-off between energy consumption and localization accuracy among the algorithms considered. Furthermore, the thesis contributes to Device Free Localization an indoor localization concept providing scalable and highly accurate location estimates (prototype: 0.36m² MSE) while using a COTS passive RFID-System and not relying on user-carried sensors
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