Perimeter coverage scheduling in wireless sensor networks using sensors with a single continuous cover range

In target monitoring problem, it is generally assumed that the whole target object can be monitored by a single sensor if the target falls within its sensing range. Unfortunately, this assumption becomes invalid when the target object is very large that a sensor can only monitor part of it. In this paper, we study the perimeter coverage problem where the perimeter of a big object needs to be monitored, but each sensor can only cover a single continuous portion of the perimeter. We describe how to schedule the sensors so as to maximize the network lifetime in this problem. We formally prove that the perimeter coverage scheduling problem is NP-hard in general. However, polynomial time solution exists in some special cases. We further identify the sufficient conditions for a scheduling algorithm to be a 2-approximation solution to the general problem, and propose a simple distributed 2-approximation solution with a small message overhead. Copyright © 2010 K.-S. Hung and K.-S. Lui.published_or_final_versio

Computing Approximate Solutions to the Art Gallery Problem and Watchman Route Problem by Means of Photon Mapping

Wireless sensor networks (WSNs) can be partitioned component sensor nodes (SNs) who are meant to operate and sense information arriving from multiple spectra in their environment. Determining where to place a single SN or multiple SNs such that the amount of information gained is maximized while the number of SNs used to gain that information is minimized is an instance of solving the art gallery problem (AGP). In order to solve the AGP, we present the Sensor Placement Optimization via Queries (SPOQ) algorithm that uses level sets populated by queries to a photon map in order to find observation points that sense as many photons as possible. Since we are using photon mapping as our means of modeling how information is conveyed, SPOQ can then take into account static or dynamic environmental conditions and can use exploratory or precomputed sensing. Unmanned vehicles can be designated more generally as UxVs where “x” indicates the environment they are expected to operate – either in the air, on the ground, underwater or on the water’s surface. Determining how to plan an optimal route by a single UxV or multiple UxVs operating in their environment such that the amount of information gained is maximized while the cost of gaining that information is minimized is an instance of solving the watchman route problem (WRP). In order to solve the WRP, we present the Photon-mapping-Informed active-Contour Route Designator (PICRD) algorithm. PICRD heuristically solves the WRP by utilizing SPOQ’s AGP-solving vertices and connecting them with the high visibility vertices provided by a photon-mapping informed Chan-Vese segmentation mesh using a shortest-route path-finding algorithm. Since we are using photon-mapping as our foundation for determining sensor coverage by the PICRD algorithm, we can then take into account the behavior of photons as they propagate through the various environmental conditions that might be encountered by a single or multiple UxVs

QoS Provision for Wireless Sensor Networks

Wireless sensor network is a fast growing area of research, receiving attention not only within the computer science and electrical engineering communities, but also in relation to network optimization, scheduling, risk and reliability analysis within industrial and system engineering. The availability of micro-sensors and low-power wireless communications will enable the deployment of densely distributed sensor/actuator networks. And an integration of such system plays critical roles in many facets of human life ranging from intelligent assistants in hospitals to manufacturing process, to rescue agents in large scale disaster response, to sensor networks tracking environment phenomena, and others. The sensor nodes will perform significant signal processing, computation, and network self-configuration to achieve scalable, secure, robust and long-lived networks. More specifically, sensor nodes will do local processing to reduce energy costs, and key exchanges to ensure robust communications. These requirements pose interesting challenges for networking research. The most important technical challenge arises from the development of an integrated system which is 1)energy efficient because the system must be long-lived and operate without manual intervention, 2)reliable for data communication and robust to attackers because information security and system robustness are important in sensitive applications, such as military. Based on the above challenges, this dissertation provides Quality of Service (QoS) implementation and evaluation for the wireless sensor networks. It includes the following 3 modules, 1) energy-efficient routing, 2) energy-efficient coverage, 3). communication security. Energy-efficient routing combines the features of minimum energy consumption routing protocols with minimum computational cost routing protocols. Energy-efficient coverage provides on-demand sensing and measurement. Information security needs a security key exchange scheme to ensure reliable and robust communication links. QoS evaluation metrics and results are presented based on the above requirements

Design and analysis of sensing scheduling algorithms under partial coverage for object detection in sensor networks

Abstract—Object detection quality and network lifetime are two conflicting aspects of a sensor network, but both are critical to many sensor applications such as military surveillance. Partial coverage, where a sensing field is partially sensed by active sensors at any time, is an appropriate approach to balancing the two conflicting design requirements of monitoring applications. Under partial coverage, we develop an analytical framework for object detection in sensor networks, and mathematically analyze average-case object detection quality in random and synchronized sensing scheduling protocols. Our analytical framework facilitates performance evaluation of a sensing schedule, network deployment, and sensing scheduling protocol design. Furthermore, we propose three wave sensing scheduling protocols to achieve bounded worst-case object detection quality. We justify the correctness of our analyses through rigorous proof, and validate the effectiveness of the proposed protocols through extensive simulation experiments. Index Terms—Sensor networks, object detection quality, system lifetime.

Arquitectura multi-agente y protocolo de comunicación para dar soporte a sistemas basados en conocimiento en redes de sensores inalámbricos

[ES] En la presente tesis se presenta una arquitectura multi-agente, cuya finalidad es la de conseguir la gestión autónoma de los recursos energéticos de un nodo en una red de sensores inalámbricos, a través de sistemas borrosos basados en reglas, apoyándose en la capacidad de comunicación que aportaría un nuevo protocolo de aplicación. Así pues, en la arquitectura multi-agente desarrollada, los agentes son modelados a través de sistemas borrosos basados en reglas cuya función es la de conseguir una gestión eficiente del ciclo de trabajo de un sensor. Así mismo, un nuevo protocolo de aplicación específico da soporte a toda la red de sensores, haciéndola además, disponible desde Internet. Los resultados obtenidos muestran que la integración propuesta, así como el protocolo de comunicación desarrollado, cumplen satisfactoriamente con los objetivos marcados, pudiéndose concluir que los sistemas borrosos basados en reglas permiten modelar efectivamente el comportamiento de estos agentes.[EN]n this thesis it is presented a multi-agent architecture whose purpose is to achieve the autonomous management of the resources of a sensor through fuzzy rule-based systems. Moreover, those systems would rely on the communication services that bring a new application protocol. Therefore, those agents are modelled by fuzzy rule-based systems to achieve an efficient management of the duty cycle of a sensor. In addition, a new specific application protocol that supports the entire sensors network has been developed, making the network available from the Internet, too. The obtained results show that the proposed integration satisfactorily meets the objectives. Thus, it can be concluded that fuzzy rule-based systems can effectively model the behaviour of an agent in charge of managing the energy resources of a sensor. Moreover, thanks to the use of a specific application protocol, those agents can be managed within a sensor network.Tesis Univ. Jaén. Departamento de Ingeniería Telemática, leída el 1 de diciembre de 201