Thesis (M.S.)--Auburn University, 2007. / Abstract. Vita. Includes bibliographic references (ℓ. 51-55)

Thesis (Ph.D.)--George Mason University, 2008. / Vita: p. 152. Thesis director: Robert Simon. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Science. Title from PDF t.p. (viewed Jan. 8, 2009). Includes bibliographical references (p. 144-151). Also issued in print.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2010. / Title from title screen (site viewed July 8, 2010). PDF text: 179 p. : col. ill. ; 13 Mb. UMI publication number: AAT 3397143. Includes bibliographical references. Also available in microfilm and microfiche formats.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Steganography and covert-communications represent a great and real threat today more than ever due to the evolution of modern communications. This doctoral work proposes defenses against such covert-communication techniques in two threatening but underdeveloped domains. Indeed, this work focuses on the novel problem of visual sensor network steganalysis but also proposes one of the first solutions against video steganography. The first part of the dissertation looks at covert-communications in videos. The contribution of this study resides in the combination of image processing using motion vector interpolation and non-traditional detection theory to obtain better results in identifying the presence of embedded messages in videos compared to what existing still-image steganalytic solutions would offer. The proposed algorithm called MoViSteg utilizes the specifics of video, as a whole and not as a series of images, to decide on the occurrence of steganography. Contrary to other solutions, MoViSteg is a video-specific algorithm, and not a repetitive still-image steganalysis, and allows for detection of embedding in partially corrupted sequences. This dissertation also lays the foundation for the novel study of visual sensor network steganalysis. We develop three different steganalytic solutions to the problem of covert-communications in visual sensor networks. Because of the inadequacy of the existing steganalytic solutions present in the current research literature, we introduce the novel concept of preventative steganalysis, which aims at discouraging potential steganographic attacks. We propose a set of solutions with active and passive warden scenarii using the material made available by the network. To quantify the efficiency of the preventative steganalysis, a new measure for evaluating the risk of steganography is proposed: the embedding potential which relies on the uncertainty of the image’s pixel values prone to corruption.

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Philosophiae Doctor - PhD / Wireless sensor networks (WSNs) have become a popular research area that is widely gaining the attraction from both the research and the practitioner communities due to their wide area of applications. These applications include real-time sensing for audio delivery, imaging, video streaming, and remote monitoring with positive impact in many fields such as precision agriculture, ubiquitous healthcare, environment protection, smart cities and many other fields. While WSNs are aimed to constantly handle more intricate functions such as intelligent computation, automatic transmissions, and in-network processing, such capabilities are constrained by their limited processing capability and memory footprint as well as the need for the sensor batteries to be cautiously consumed in order to extend their lifetime. This thesis revisits the issue of the energy efficiency in sensor networks by proposing a novel clustering approach for routing the sensor readings in wireless sensor networks. The main contribution of this dissertation is to 1) propose corrective measures to the traditional energy model adopted in current sensor networks simulations that erroneously discount both the role played by each node, the sensor node capability and fabric and 2) apply these measures to a novel hierarchical routing architecture aiming at maximizing sensor networks lifetime. We propose three energy models for sensor network: a) a service-aware model that account for the specific role played by each node in a sensor network b) a sensor-aware model and c) load-balancing energy model that accounts for the sensor node fabric and its energy footprint. These two models are complemented by a load balancing model structured to balance energy consumption on the network of cluster heads that forms the backbone for any cluster-based hierarchical sensor network. We present two novel approaches for clustering the nodes of a hierarchical sensor network: a) a distanceaware clustering where nodes are clustered based on their distance and the residual energy and b) a service-aware clustering where the nodes of a sensor network are clustered according to their service offered to the network and their residual energy. These approaches are implemented into a family of routing protocols referred to as EOCIT (Energy Optimization using Clustering Techniques) which combines sensor node energy location and service awareness to achieve good network performance. Finally, building upon the Ant Colony Optimization System (ACS), Multipath Routing protocol based on Ant Colony Optimization approach for Wireless Sensor Networks (MRACO) is proposed as a novel multipath routing protocol that finds energy efficient routing paths for sensor readings dissemination from the cluster heads to the sink/base station of a hierarchical sensor network. Our simulation results reveal the relative efficiency of the newly proposed approaches compared to selected related routing protocols in terms of sensor network lifetime maximization.

<p>Communication in a sensor network needs guaranteed reception of data without fail and providing security to it. The authenticity and confidentiality of the data has to be ensured as sensors have limited hardware resources as well as the bandwidth. This thesis addresses the security aspects in wireless sensor networks. The main task of the project is to identify the critical security parameters for these distributed embedded systems. The sensors have extremely limited resources: small amount of memory, low computation capability and poor bandwidth. For example, a sensor platform can have 8KB of flash memory, a 4MHz 8-bit Atmel processor, and a 900MHz radio interface. Various security threats posed to these small wireless sensor networks has been made and solutions proposed. Secure communication between these communicating partners is to be achieved using cryptography.</p>

<p>In the recent past, wireless sensor networks have been introduced to use in many applications. To </p><p>design the networks, the factors needed to be considered are the coverage area, mobility, power </p><p>consumption, communication capabilities etc. The challenging goal of our project is to create a </p><p>simulator to support the wireless sensor network simulation. The network simulator (NS-2) which </p><p>supports both wire and wireless networks is implemented to be used with the wireless sensor </p><p>network. This implementation adds the sensor network classes which are environment, sensor </p><p>agent and sensor application classes and modifies the existing classes of wireless network in NS- </p><p>2. This NS-2 based simulator is used to test routing protocols – Destination-Sequenced Distance </p><p>Vector (DSDV), and Ad-Hoc On-Demand Distance Vector (AODV) as one part of simulations. </p><p>Finally, the sensor network application models and the extension methods of this NS-2 based </p><p>simulator for simulations in specific wireless sensor network applications are proposed.</p>

CytoSensor system integration and design is driven by requirements generated by the need to complete biological experiment operations. The system is used for toxin-based detection which will identify and quantify unknown input toxins by using a biosensor based on a living fish chromatophore. The system consists of 3 main parts: biosensor, data acquisition and data interpretation. This thesis is focused on data acquisition. Acquisition, in this case, is via a color camera since the cells have an easily measurable visual output. The major initial task is to select the hardware specifications that satisfy user requirements. Components are obtained from different vendors. The understanding of each component is, therefore, very important to maximize the system performance and compatibility. The second major task is to design the software interface and components to manage the data acquisition. This can be separated into 2 parts. The first part is acquisition management and control. The second part is the human interface. This thesis focuses on the human interface. The human interface is the part that communicates between the user and the system. The system will send the system status to the user. The user will then direct the system through the operation. Operators may not be familiar with complicated computerized systems. A user-friendly interface is important to reduce mistakes and to facilitate the operation. The goal of this design is to direct the user from a single look at the interface. The interface should therefore contain all the useful and necessary information. The design of the user interface begins with gathering the necessary information and making a decision about which information is important to deliver to the user. A clean, tidy and informative user interface will lead to efficient operation. The design methodology is to group the same information within the same area and be consistent. Machine operation is very important, as well. In order to reduce the confusion in system operation, the machine operating protocol is designed to be very similar to the traditional protocol. Design of the machine operation is through interactions with the user. Sending user information to the machine will be handled by the system management program. By simulating the user scenario, each state change will lead to changing of the state of the machine, as well. The scenario is implemented in a state-like diagram. This state diagram must be implemented carefully in order to be able to handle all the cases and exceptions. The last and most important part is putting all the components together and testing the system. All possible scenarios and features listed before designing will be tested at this point. The last test is to run actual experiments with the system. After all the tests are satisfied, the system is delivered to the user. At this time, the user might give more feedback on the system. In conclusion, the overall goal of designing this system is not only to make the system for this specific application. However, the goal is to design a general application that will be able to apply to different sensor application. By changing the core management and hardware, the software can easily fit another sensor application. / Graduation date: 2003