Thesis (M.Sc.)--York University, 2008. Graduate Programme in Computer Science. / Typescript. Includes bibliographical references (leaves 147-152). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR51580

Thesis (Ph. D.)--University of Louisville, 2008. / Department of Electrical and Computer Engineering. Vita. "December 2008." Includes bibliographical references (leaves 110-116).

Thesis (M.S.)--University of Missouri-Columbia, 2005. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (July 17, 2006) Includes bibliographical references.

Thesis (M.S.)--Washington State University, December 2007. / Includes bibliographical references (p. 72-77).

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

AN ABSTRACT OF THE THESIS OF ISMAIL GUNEYDAS, for the Master of Science degree in Computer Science, presented on 5th November 2008, at Southern Illinois University Carbondale. TITLE: ACTOR POSITIONING IN WIRELESS SENSOR AND ACTOR NETWORKS USING MATCHING THEORY. MAJOR PROFESSOR: Dr. KEMAL AKKAYA In most of the Wireless sensor and actor network (WSAN) applications, the locations for the actors are determined autonomously by the collaboration of actors and/or sensors in order to eliminate human intervention as much as possible. Particularly, sensors can collaborate in a distributed manner and elect cluster-heads (CHs) among them which will be taking into account the distribution of the sensors within the region. In such cases, the actors can then move to such sensor locations (i.e., replace them as cluster-heads) as they have the ability to move by talking to nearby sensors/actors. Such movement, however, should be done wisely in order to minimize the total distance that will be traveled by the actors so that their lifetimes can be extended. Nevertheless, this may not be possible since not all the actor and CH locations will be known to each actor. In addition, the actors may not be reachable to each other and thus conflicts in assignments can easily occur. In this thesis, we propose an actor-CH location matching algorithm which will detect the CH locations and assign the actors to such locations in a distributed manner with the minimized travel distance. We adapt the Gale-Shapley (G-S) stable matching algorithm from Matching Theory in order to prevent conflicts and minimize the travel distance. In this matching algorithm, actors are regarded as men and CHs are regarded as women. First, we detect the CH locations through running a quorum-based search within the sensor network. Later, G-S is run on actor and CH locations. Once the locations are determined, each actor moves to that location. We evaluated the performance of our approach through simulation and have shown that our approach can produce results very close to the brute force approach.

Wireless sensor network has been an area of interest among researchers. Designing a wireless sensor network involves multiple issues such as size and processing capacity of the sensors, number of the cluster heads, number of the base stations, routing protocols, battery of the nodes, layout of the system, etc. Battery is a critical factor, since sensor networks do not involve maintenance as they are situated in remote places. Hence the available battery must be utilized effectively to increase the efficiency. In our study we address issues associated with battery such that to increase the lifetime of the system. Existing standards for the sensors are implemented with each node having equal battery level `B' referred to as `Uniform system' in our study. Thus total amount of battery consumed by N nodes is `N * B'. In our approach we study the distribution of this `N * B' battery in non-uniform manner, referred as `Non-uniform system', such that each node would be allocated with different battery level depending upon its position and amount of information it receives and transmits. Initially we commence with the observation of the behavior of this approach on a chain of nodes. These nodes generate information at constant rate and transmit per cycle. We observed that there is a huge amount of increase in the lifetime as compared to lifetime of the uniform system. We step further in our experimentation by restricting the amount of battery each node can have and then quantizing it. Results indicate that only 3 levels of batteries instead of N, give us significant increase in the lifetime. These results validate our approach for practical implementation. We progressed by observing success of our approach on random topology where nodes are laid randomly in the area of experimentation. Approximately same increase in the lifetime as achieved initially without restricting battery levels can be achieved. Simulation results show that non-uniform system performs much better than uniform system. This approach of non uniform battery levels can be implemented in sensor networks such that system lives longer giving more throughput and thus increasing efficiency.

Wireless sensor networks (WSNs) are systems of resource-constrained sensor nodes (SNs), distributed throughout a sensor field. Energy limitations persist due to the wireless nature of SNs and an interest in minimizing the cost and physical footprint of SNs. Due to the resource-constrained nature of SNs, much WSN research has focused on energy-efficient communication algorithms. Communication algorithms are necessary for energy-efficient data transmission between SNs and the transmission of data collected by SNs to a base station. A popular algorithm known as Low-Energy Adaptive Clustering Hierarchy (LEACH) achieves more energy-efficient communication by organizing SNs into clusters for localized communication. When SNs are mobile, the energy efficiency of LEACH is degraded because of geographic dispersion of SN clusters. This thesis proposes LEACH-Centered Cluster-head (LEACH-CCH), a clustering algorithm aimed at improving WSN lifetime in cases of stationary and mobile sensor nodes. Mobile sensor network applications are explored including vehicle-to-infrastructure communication networks.

Resource constraints and wireless nature of communication render the securing of wireless sensor networks (WSNs) challenging. Ad hoc deployment of sensors make key pre distribution schemes (KPSs) more suitable for establishing security associations between resource constrained sensors. Specifically, probabilistic key pre distribution schemes (PKPSs) which mandate very low computational complexity, are good choices for securing WSNs. In this thesis we examine the suitability of PKPSs for sensor networks and propose several improvements to PKPSs for their use in WSNs. The specific contributions of this thesis are fourold: ? Strategies to improve trade-offs between connectivity and collusion resistance. ? Enumeration of the need for authentication, and strategies to improve the strength of authentication. ? Exploiting imbalances between costs of different resources (computation, storage), and ? Taking advantage of external storage resources to improve security of WSNs.

No description available.