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SEKHAR, SANDHYAA DISTANCE BASED SLEEP SCHEDULE ALGORITHM FOR ENHANCED LIFETIME OF HETEROGENEOUS WIRELESS SENSOR NETWORKS
MS, University of Cincinnati, 2005, Engineering : Computer Engineering
This thesis describes the concept of sensor networks which has been made viable by the convergence of MEMS system technology and efficient routing protocols. Sensor nodes possess finite, non-renewable energy that they expend in sensing a multitude of modalities including temperature, moisture, pressure, light and infrared radiation. A radio-interconnected collection of such sensors forms a sensor network and the information collected from the network is transmitted for analysis at a distant location termed as the sink. The main purpose of a sensor network is to gather information about the various parameters of the area in which it is deployed and to transmit this information to the sink for appropriate utilization. A wireless sensor node is capable of only a limited amount of communication and processing. Therefore, unlike traditional networks, where the objective is to maximize channel throughput, the chief consideration in a sensor network is to extend the system lifetime as well as system robustness. Wireless ad hoc and sensor networks are comprised of energy–constrained nodes. This limitation has led to the dire need for energy-aware protocols to produce an efficient network. Heterogeneity is introduced in a wireless sensor network by having a large number of low power sensor nodes and a small number of more powerful nodes to serve as cluster heads. We propose a self-tuning scheme that improves the lifetime of a heterogeneous wireless sensor network by appropriately scheduling the transmission rate of individual sensor nodes in the network. We consider a distance based sleep scheduling problem for equal energy consumption rates in low power sensor nodes and evaluate the optimal settings required in a heterogeneous sensor network. We evaluate the efficiency of our proposed algorithm based on an analytical model and perform simulations to verify the adequacy of our scheme in terms of important network parameters and compare with existing heterogeneous sensor networks. We provide an estimate of the optimal number of clusters required, expected energy in a cluster head and the extent of network coverage. The proposed scheme is observed to improve network lifetime while conserving energy and maximizing information gathering at the sink.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

Energy-aware systems; Low-power design; Mobile environments; Heterogeneous Sensor networks; Wireless Sensor Networks

Fan, Kai-WeiOn Structure-less and Everlasting Data Collection in Wireless Sensor Networks
Doctor of Philosophy, The Ohio State University, 2008, Computer and Information Science

Computing and maintaining network structures for efficient data aggregation incurs high overhead for dynamic events where the set of nodes sensing an event changes with time. Prior works on data aggregation protocols have focused on tree-based or cluster-based structured approaches. Although structured approaches are suited for data gathering applications, they incur high maintenance overhead in dynamic scenarios for event-based applications. The goal of this dissertation is to design techniques and protocols that lead to efficient data aggregation without explicit maintenance of a structure.

We propose the first structure-free data aggregation technique that achieves high efficiency. Based on this technique, we propose two semi-structured approaches to support scalability. We conduct large scale simulations and real experiments on a testbed to validate our design. The results show that our protocols can perform similar to an optimum structured approach which has global knowledge of the event and the network.

In addition to conserving energy through efficient data aggregation, renewable energy sources are required for sensor networks to support everlasting monitoring services. Due to low recharging rates and the dynamics of renewable energy such as solar and wind power, providing data services without interruptions caused by battery runouts is non-trivial. Moreover, most environment monitoring applications require data collection from all nodes at a steady rate. The objective is to design a solution for fair and high throughput data extraction from all nodes in the network in presence of renewable energy sources. Specifically, we seek to compute the lexicographically maximum data collection rate for each node in the network, such that no node will ever run out of energy. We propose a centralized algorithm and an asynchronous distributed algorithm that can compute the optimal lexicographic rate assignment for all nodes. The centralized algorithm jointly computes the optimal data collection rate for all nodes along with the flows on each link, while the distributed algorithm computes the optimal rate when the routes are pre-determined. We prove the optimality for both the centralized and the distributed algorithms, and use a testbed with 158 sensor nodes to validate the distributed algorithm.

Committee:

Prasun Sinha (Advisor); Anish Arora (Committee Member); David Lee (Committee Member)

Subjects:

Computer Science

Keywords:

Data Aggregation; Sensor Networks; Structure-less; Rechargeable Sensor Networks

Basheer, Al-QassabReliability of Data Collection and Transmission in Wireless Sensor Networks
Master of Science in Engineering, Youngstown State University, 2013, Department of Electrical and Computer Engineering
A network of wireless sensor nodes that are connected to a centralized base station is presented to conduct a study on reliability of data collection and transmission in wireless sensor networks (WSNs) with focus on data loss and data duplication. Software applications for specific sensor nodes called Sun SPOTs are presented, and programming techniques, for example packet transmitting time delay and data checking for loss and duplication, are implemented in these software applications to improve the functionality of the network. Acceleration data on a vibration plate are collected at sampling frequency of 100 Hz to validate the operation of the network. Additionally, the wireless sensor network is optimized to enhance the synchronization of data collection from different nodes. The result of this research shows that the reliability of the network is related to data sampling frequency, synchronization of the wireless data traffic, wireless sensor node signal strength, and wireless data routing protocols. The indoor tests on signal strength show the limitation of -70 dBm and higher for optimum data collection without data or packet loss.

Committee:

Li Frank, Ph.D. (Advisor); Munro Philip, Ph.D. (Committee Member); Mossayebi Faramarz, Ph.D. (Committee Member)

Subjects:

Computer Engineering; Electrical Engineering; Engineering; Information Technology

Keywords:

Wireless sensor networks; WSN; data collection; data transmission; reliability of wireless sensor networks

Li, HailongAnalytical Model for Energy Management in Wireless Sensor Networks
PhD, University of Cincinnati, 2013, Engineering and Applied Science: Computer Science and Engineering
Wireless sensor networks (WSNs) are one type of ad hoc networks with data-collecting function. Because of the low-power, low-cost features, WSN attracts much attention from both academia and industry. However, since WSN is driven by batteries and the multi-hop transmission pattern introduces energy hole problem, energy management of WSN became one of fundamental issues. In this dissertation, we study the energy management strategies for WSNs. Firstly, we propose a packets propagation scheme for both deterministic and random deployment of WSNs so to prolong their lifetime. The essence of packets propagation scheme is to control transmission power so as to balance the energy consumption for the entire WSN. Secondly, a characteristic correlation based data aggregation approach is presented. Redundant information during data collection can be effectively mitigated so as to reduce the packets transmission in the WSN. Lifetime of WSN is increased with limited overhead. Thirdly, we also provide a two-tier lifetime optimization strategy for wireless visual sensor network (VSN). By deploying redundant cheaper relay nodes into existing VSN, the lifetime of VSN is maximized with minimal cost. Fourthly, our two-tier visual sensor network deployment is further extended considering multiple base stations and image compression technique. Last but not the least, description of UC AirNet WSN project is presented. At the end, we also consider future research topics on energy management schemes for WSN.

Committee:

Dharma Agrawal, D.Sc. (Committee Chair); Kenneth Berman, Ph.D. (Committee Member); Yizong Cheng, Ph.D. (Committee Member); Chia Han, Ph.D. (Committee Member); Wen Ben Jone, Ph.D. (Committee Member)

Subjects:

Computer Engineering

Keywords:

Wireless Sensor Networks;Wireless Visual Sensor Network;Energy Management;Data Aggregation;Gaussian Random Distribution;Lifetime Optimization;

Scherer, Drew P.Urban Free Agents: Active Territories Through Nascent Ubiquitous Networks
MARCH, University of Cincinnati, 2012, Design, Architecture, Art and Planning: Architecture

The main investigation of this thesis questions the predefined territories within the downtown urban infrastructure of Cincinnati in an attempt to redefine the normative paths of play and interaction through evolving growths and swells of activity. These formations will be investigated and determined through the redevelopment of neglected infrastructure and their influence on local nodes within the urban setting. As the city has continued to thin in pedestrian attraction and vacancies increase, these broken and under- utilized properties can be used to inject new life and density into the city. These territories will be used as an intensifier in creating a remapping of the city and how it evolves through an open-content model.

This interaction will be activated by modern ubiquitous virtual networks that draw populations of all scales and backgrounds together. By harnessing the collective power of personal electronic networked devices the anonymous public becomes agent in directing the swell of content within these armatures. The goal is to introduce a new architype wherein the separation between virtual and physical realms are blurred, and a more dynamic social space is derived.

Committee:

George Bible, MCiv.Eng (Committee Chair); Rebecca Williamson, PhD (Committee Member)

Subjects:

Architecture

Keywords:

Mobile Technology;Sensor Networks;Active Typologies;Temporal Space;Open Content;;

VENUTURUMILLI, ABHINAYACHIEVING ROBUST WIRELESS SENSOR NETWORKS THROUGH SELF ORGANIZATION OF HETEROGENEOUS CONNECTIVITY
MS, University of Cincinnati, 2006, Engineering : Electrical Engineering
Wireless sensor networks with randomly deployed nodes are becoming increasingly viable for several applications. The nodes in these networks communicate wirelessly. Most models for wireless sensor networks have used homogeneous nodes with the same communication range. These networks have symmetric connectivity, which makes them easier to analyze using percolation models. It is well-known that heterogeneous networks, where each node can customize its transmission radius, potentially provide many advantages. However, devising algorithms for such reconfiguration has proved to be difficult. Scalability requires that any configuration process be completely distributed, which presents the classic problem confronting all self-organized systems: How to obtain global optimality from local adaptation. We present a heuristic for the self-organization of heterogeneous networks with the explicit goal of producing robust networks that minimize energy consumption. The results show that the heuristic networks are both effective and efficient than the homogeneous networks in all the measures considered.

Committee:

Dr. Ali Minai (Advisor)

Subjects:

Computer Science

Keywords:

heterogeneous; sensor networks; distributed; robust; connectivity; topology control

ARUMUGAM, RAJKUMARSCRIBE: SELF-ORGANIZED CONTENTION AND ROUTING IN INTELLIGENT BROADCAST ENVIRONMENTS
MS, University of Cincinnati, 2002, Engineering : Electrical Engineering
With advances in miniaturization, wireless communication, and the theory of self-organizing systems, it has become possible to consider scenarios where a very large number of networkable sensors are deployed randomly over an extended environment and organize themselves into a network. Such networks, which we term large-scale sensor networks (LSSN's), can be useful in many situations, including military surveillance, environmental monitoring, disaster relief, etc. The idea is that, by deploying an LSSN, an extended environment can be rendered observable for an external user (e.g., a monitoring station) or for users within the system (e.g., persons walking around with palm-sized devices or other nodes in the system). Unlike custom-designed networks, these randomly deployed networks need no pre-design and configure themselves through a process of self-organization. The sensor nodes themselves are typically anonymous, and information is addressed by location or attribute rather than by node ID. This approach provides several advantages, including: 1) Scalability; 2) Robustness; 3) Flexibility; 4) Expandability; and 5) Versatility. Indeed, this abstraction is implicit in such ideas as smart paint, smart dust, and smart matter. In this thesis, we present a well-developed paradigm for random LSSN's, including a model for the nodes and viable broadcast-based protocols for channel access and network organization. We explore methods for intelligent broadcast where the efficiency in the messaging process is created by a node's decision to rebroadcast a message. This allows the communication process to utilize redundant paths without unnecessary messaging. We evaluate the performance of the network as the degree of sophistication of the underlying ommunication mechanism grows. We explore a range of methods, starting with simple flooding and going up to unicast communication. We also study the robustness of each of these protocols when subjected to random failures.

Committee:

Dr. Ali A. Minai (Advisor)

Keywords:

self-organization; sensor networks; broadcast; redundancy routing

JAIN, NEHAENERGY AWARE AND ADAPTIVE ROUTING PROTOCOLS IN WIRELESS SENSOR NETWORKS
PhD, University of Cincinnati, 2004, Engineering : Computer Science and Engineering
Recent technological advances have enabled distributed micro-sensing for large scale information gathering through a network of tiny, low power devices or nodes equipped with programmable computing, multiple sensing and communication capabilities. This network of sensor nodes, known as a wireless sensor network, has revolutionized remote monitoring applications because of its ease of deployment, ad hoc connectivity and cost-effectiveness. In this dissertation, we design distributed routing protocols for minimizing energy consumption in a sensor network. There are two main contributions of this work. The first contribution is the design of an energy aware multiple path routing protocol to route heavy data traffic between a source and a destination node in a sensor network. The protocol spreads the routing load between the source and destination nodes over a large number of sensor nodes to minimize disparity in the energy levels of the sensor nodes. We also grade the multiple paths based on their route length to support time critical queries on the shortest available paths. The second contribution is the design of a communication architecture that supports distributed query processing to evaluate spatio-temporal queries within the network. We represent these queries by query trees and distribute query operators to appropriate sensor nodes. As operator execution demands high computation capability, we propose use of a heterogenous sensor network where query operators are assigned to sparsely deployed resource-rich nodes within a dense network of low power sensor nodes. We design an adaptive, decentralized, low communication overhead algorithm to determine an operator placement on the resource-rich nodes in the network to minimize cost of transmitting data in the routing tree constructed to continuously retrieve data from a set of spatially distributed geographical regions to the sink. To the best of our knowledge, this is the first attempt to build an energy aware routing infrastructure to enable in-network processing of spatio-temporal queries. In order to maximize energy savings the proposed multiple path routing protocol can be used to route data between the nodes that form the routing tree.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

Wireless Sensor Networks; Routing Protocols; Energy Aware; Decentralized algorithms

Yoon, Suk-UnDynamic Radio Resource Allocation in Wireless Sensor and Cognitive Radio Networks
Master of Science, The Ohio State University, 2009, Electrical and Computer Engineering

In wireless networks, it is required to change an operating frequency as part of the radio resource management due to strong interference or system requirements of accessing radio resources. In this thesis, we propose two radio resource management schemes in wireless sensor networks and cognitive radio networks. In the proposed schemes, sensor networks switch to a new channel when they detect strong interference and a secondary user in cognitive radio networks moves to a new spectrum when it detects or predicts the presence of a primary user.

In the first part of the thesis, we propose a channel hopping scheme which can be used for interfered wireless networks. With the additive functionality of a channel hopping mechanism on the sensor network stack, we aim to avoid the interference from other sensor nodes and wireless technologies on ISM band as well as avoid narrow-band jamming. For simple and reliable channel hopping, we introduce an Adaptive Channel Hopping scheme, a spectrum environment aware channel hopping scheme, for interference robust wireless sensor networks. When the channel status becomes suboptimal to communicate, the adaptive channel hopping lets the sensors switch to a new clean channel. To generate channel selection/scanning orders which minimize channel hopping latency, we use two parameters which are link quality indicator (LQI) and channel weighting. The proposed adaptive channel hopping scheme is evaluated through simulations. Simulation results indicate that the proposed scheme significantly reduces the channel hopping latency and selects the best quality channel.

In the second part of the thesis, we propose a novel approach to spectrum management in cognitive radio networks. To support flexible use of spectrum, cognitive radio networks employ spectrum mobility management schemes, including spectrum handoff, which refers to the switching of the operating spectrum due to changes in licensed (primary) user activity. Spectrum handoff inevitably results in temporary disruption of communication for the unlicensed (secondary) user operating in a licensed band opportunistically. Minimization of secondary user service disruption is an important objective of spectrum handoff schemes. In this thesis, we introduce a new type of spectrum handoff called Voluntary Spectrum Handoff assisted by a primary user spectrum usage estimation scheme. The two mechanisms proposed under voluntary spectrum handoff method estimate opportune times to initiate unforced spectrum handoff events to facilitate setup and signaling of alternative channels without having communication disruption, which occurs when a secondary user is forced out of an operating spectrum due to primary user activity. To estimate primary user spectrum usage, channel usage information is continuously updated with a fixed spectrum sensing window and a variable history window. Proposed voluntary spectrum handoff and primary usage estimation schemes are evaluated through extensive simulations. Simulation results indicate that the proposed schemes significantly reduce the communication disruption duration due to handoffs.

Committee:

Eylem Ekici (Advisor); Bradley Clymer, D. (Committee Member)

Subjects:

Engineering

Keywords:

Channel Hopping; Wireless Sensor Networks; Spectrum Handoff; Cognitive Radio Networks

Sang, LifengDesigning Physical Primitives For Secure Communication In Wireless Sensor Networks
Doctor of Philosophy, The Ohio State University, 2010, Computer Science and Engineering

A sensor network typically refers to a collection of sensor nodes equipped with sensing, communication and processing capabilities. It brings an opportunity to solve many difficult problems including real time monitoring, tracking, and controlling. While the applications of sensor networking become many and varied, security has always been one of the major concerns in real deployments. In this dissertation, we design physical primitives for secure communication in wireless sensor networks, and develop a wireless security framework to provide conventional security services.

We investigate the feasibility of achieving perfect secrecy and information authenticity without shared secrets via two physical primitives: (i) cooperative jamming primitive, where we introduce a secure coding problem in which not only the sender but also the receiver participates in the coding. In essence, the receiver’s role is to selectively jam the sender’s transmission at the level of bits, bytes, or packets. We then design a class of secure codes, called “dialog codes”, for diverse channel models and receiver models. (ii) spatial verification primitive, where we exploit the spatial signature induced by the radio communications of a node on its neighboring nodes, and design a spatial primitive that robustly and efficiently validates the authenticity of the source of messages. To address trust initialization, we propose a zero knowledge proof alternative that allows bootstrapping trust among individuals in a distributed way.

Based on the cooperative jamming primitive and spatial verification primitive, we develop a framework for wireless security that provides conventional security services that include confidentiality, identity authentication, message authentication, integrity, sender non-repudiation, receiver non-repudiation and anonymity, not only for single-hop and end-to-end communications, but unicast and broadcast contexts as well. We show for the first time that a wide variety of security services are possible without any shared secrets and with only a small basis of physical primitives.

Committee:

Anish Arora (Advisor); David Lee (Committee Member); Dong Xuan (Committee Member)

Subjects:

Computer Science

Keywords:

wireless security; physical primitive; sensor networks

Naik, Vinayak ShashikantReliable and secure data transport in large scale wireless networks of embedded devices
Doctor of Philosophy, The Ohio State University, 2006, Computer and Information Science
Recent advances in semiconductor technology have resulted in techniques that can build miniaturized radios and sensor-actuators, which can be deployed in the physical world in a large scale. These inexpensive devices can be used to provide coordinated dense sensing, processing, and communicating. Combining these capabilities with robust system software will empower physical sciences with real-time data of high fidelity. To realize this opportunity, computer scientists must address new challenges posed for development of robust system software for the large scale resource constrained wireless networks of embedded devices (sensors). These devices have limited resources in terms of processing, memory, radio bandwidth, and energy. Further, once deployed these devices will necessarily remain untouched and expect to work for an extended period of time. All though Internet is a large scale network, all of the above mentioned constrained do not apply to the nodes in the Internet. Therefore, network services must be designed specifically for the large scale wireless sensor networks. The network services for large scale sensor network must have low time complexity and memory complexity. We provide low complexity reliable and secure data transport for large scale wireless networks of embedded devices. We focus on bulk data transport for two of the most commonly used services, viz. data dissemination and data collection. Our services are better than the state-of-the-art. We address the problem of key maintenance for providing secured communication in the presence of key compromise and denial-of-service attacks. We also investigate the use of testbed to facilitate experimentations for large scale wireless networks.

Committee:

Anish Arora (Advisor)

Subjects:

Computer Science

Keywords:

Network protocols; Real-time systems and embedded systems; Wireless; Wireless sensor networks; Computer security

Chakraborty, SuryadipData Aggregation in Healthcare Applications and BIGDATA set in a FOG based Cloud System
PhD, University of Cincinnati, 2016, Engineering and Applied Science: Computer Science and Engineering
The Wireless Body Area Sensor Network (WBASN) is a wireless network of wearable computing devices including few medical body sensors which capture and transmit different physiological data wirelessly to a monitoring base station. When a physiological sensor continuously senses and generates huge amount of data, the network might become congested due to heavy traffic and it might lead to starvation and ineffectiveness of the WBASN system. This had led to the beginning of our first problem in this research which is the use of aggregation of data so as to reduce the traffic, enhancing the network life time, and saving the network energy. This research also focuses on dealing with huge amount of healthcare data which is widely known today as `BIGDATA’. Our research investigates the use of BIGDATA and ways to analyze them using a cloud based architecture that we have proposed as FOG Networks which improves the use of cloud architecture. During the work of data aggregation, we propose to use of the statistical regression polynomial of the order 4, and 8. Due to computation, we performed the 6th order coefficient computation and analyzed our results with real-time patient data with compression ratio and correlation coefficients. We also focus on studying the energy saving scenarios using our method and investigate how the node failure scheme would be handled. While focusing on building a polynomial based data aggregation approach in the WBASN system which involves summing and aggregating of wireless body sensors data of the patient's, we noticed the problem of dealing with thousand and millions of patients data when we run a WBASN system for continuous monitoring purpose. We could not also deal with such big amount of data in the small storage of the physiological sensors with small computation abilities of them. So, there is an immediate necessity of an architecture and tools to deal with these thousands of data commonly known today as the BIGDATA. To analyze the BIGDATA, we propose to implement a robust cloud-based structure that uses Hadoop based map reduce system and get some meaningful interpretation of the patient's monitoring data for the medical practitioners, doctors and medical representatives in a very time-efficient manner. As getting thousands of BIGDATA with patient’s secured health information is a proprietary and licensed issue, we examined our cloud based BIGDATA architecture using the Twitter and Google N-gram data which are freely available in public domain. In our next proposed task, we plan to implement a robust and scalable architecture of the existing cloud system which itself takes care of the short comings of the public cloud architecture such as Amazon S3, Microsoft Azure etc. Therefore, we propose to use of a newly introduced system known as the FOG networks that significantly helps the clients (medical workers monitoring the patient’s vital parameters) to easily assess, interpret and analyze the patient’s data of injuries, health parameter performance, and improvement in the health condition, associated vital parameters and emergency data arise very efficiently and more effectively.

Committee:

Dharma Agrawal, D.Sc. (Committee Chair); Amit Bhattacharya, Ph.D. (Committee Member); Rui Dai, Ph.D. (Committee Member); Chia Han, Ph.D. (Committee Member); Carla Purdy, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless body area sensor networks;Data aggregation;Cloud computing;Fog computing

Vural, SerdarInformation propagation in wireless sensor networks using directional antennas
Doctor of Philosophy, The Ohio State University, 2007, Electrical Engineering
The information propagation capability of Wireless Sensor Networks (WSN) is directly related with the properties of multihop paths. Two main measures of the multihop data propagation capability are the maximum Euclidean distance that can be covered in a multihop path and the effectiveness of the medium access control (MAC) protocol. To achieve high propagation capacity, MAC protocols should enhance the channel use by maximizing simultaneous traffics and reducing end-to-end delay in high data load scenarios often encountered in WSN data collection applications. In this regards, directional antennas offer various benefits such as the extended communication ranges, spatial reuse capability, and reduced interference patterns that enable higher network performance compared to omnidirectional antennas. In this thesis, the maximum multihop Euclidean distance covered by directional packet transmissions is evaluated for both linear and planar WSNs using analytical modeling of distance distributions. Expressions for calculating the distribution parameters are derived and provided. Comparison of experimental and analytical results demonstrate the high accuracy of the proposed models in estimating distance distributions. Furthermore, a WSN security application which utilizes the derived models for verifying sensor locations is presented. The second contribution of this thesis is the Smart Antenna-Based MAC (SAMAC) protocol designed for multihop data collection applications for WSNs with sectored antennas. A detailed protocol description as well as performance evaluation results are provided. Simulation results demonstrate that SAMAC with sectored antennas improves end-to-end delay, data throughput, and data delivery ratio under high data generation rates and highly loaded traffic conditions compared to IEEE 802.11 with omnidirectional antennas.

Committee:

Eylem Ekici (Advisor)

Keywords:

wireless sensor networks; directional antennas; information propagation

Chellappan, SriramOn deployment and security in mobile wireless sensor networks
Doctor of Philosophy, The Ohio State University, 2007, Computer and Information Science

Wireless sensor networks have become increasingly pervasive with promises to fulfill many of our critical necessities today. One issue that has permeated sensor networks recently is mobility. Broadly, mobility in sensor networks can be categorized into two classes: Internal mobility and External mobility. Internal mobility is the class where sensors themselves can move from one location to another, while external mobility is the class where certain external agents (not sensors) move in the network. Both mobility classes have patent and significant impacts to sensor networks operation. However, being an emerging topic, a clear understanding of opportunities and challenges of sensor networks mobility is lacking today, and hence is an important need of the hour. In this dissertation, we make contributions in both classes of sensor networks mobility.

First, we study the issue of how sensors can use their mobility to enhance quality of network deployment. We define two representative mobility assisted sensor network deployment problems. In our mobility model, there are hard limitations in both sensors' mobility pattern and distance. Such limitations are natural due to constraints on sensors' form-factor and energy. We identify critical challenges arising in deployment under such hard mobility limitations. We then propose a suit of sensor mobility algorithms for our deployment problems, and demonstrate their performance using theoretical analysis and extensive simulations.

Second, we study the issue of external mobility in sensor networks from a security perspective. We identify a unique security threat in sensor networks called physical attacks. We define a representative model of physical attacks, wherein an external mobile agent (human being or robot) moves in the network detecting inherent physical/ electronic sensor signals to localize sensors, and then physically destroys them. We formally model such attacks in sensor networks, demonstrate their destruction potential, identify variations, and finally propose countermeasure guidelines against them.

With the emergence of mobility in wireless sensor networks, coupled with its significances, we hope that our work in this dissertation can provide strong foundations and further motivations for researchers to explore this topic that promises to revolutionarize sensor networks research in the near future and beyond.

Committee:

Dong Xuan (Advisor); Eylem Ekici (Other); Ten Lai (Other)

Subjects:

Computer Science

Keywords:

Wireless Sensor Networks;

Bender, Paul AnthonyEnergy efficient Image Video Sensor Networks
Doctor of Philosophy (PhD), Wright State University, 2008, Computer Science and Engineering PhD

Image Video Sensor Networks are emerging applications for sensor network technologies. The relatively large size of the data collected by image video sensors presents new challenges for the sensor network in terms of energy consumption and channel capacity. We address each of these issues through the use of a high density network deployment utilizing some nodes as dedicated relay nodes.

A high density network allows network nodes to reduce their transmission power. This reduction in transmission power allows each node to conserve power and simultaneously increases the potential for spatially concurrent transmissions within the network, resulting in improved network throughputs. The use of additional relay nodes may further increase the potential for such spatially concurrent transmissions, without increasing the relay burden for each node by maintaining the same number of data generating sources in the network.

In this work, we show analytically how a high density network effects energy consumption and network capacity. We discuss the constraints placed on a high density sensor network deployment due to application latency requirements, sensor coverage requirements, connectivity requirements, and node costs.

Furthermore, we implement an Image/Video Sensor Web, an Internet enabled testbed for studying the implementation of a high density network deployment for Image/Video Sensor Networks. We utilize this testbed to verify our analytical energy results, and to study the reliable data delivery requirements necessary to successfully deploy an Image/Video Sensor Network.

Committee:

Yong Pei, PhD (Advisor); Bin Wang, PhD (Committee Member); Soon Chung, PhD (Committee Member); Zhiqiang Wu, PhD (Committee Member); Shih-Ta Hsiang, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Sensor Networks; Multimedia; Energy Efficiency

MANJESHWAR, ARATI BHATENERGY EFFICIENT ROUTING PROTOCOLS WITH COMPREHENSIVE INFORMATION RETRIEVAL FOR WIRELESS SENSOR NETWORKS
MS, University of Cincinnati, 2001, Engineering : Computer Science
Wireless sensor networks are expected to find wide applicability and increasing deployment in coming years, as they enable reliable monitoring and analysis of the environment. Users of such a system will expect to get a real time warning when time-critical situations occur in the network and also to be able to retrieve any required information by issuing queries to the network. In this thesis, we propose a formal classification of sensor networks, based on their mode of functioning, as proactive and reactive networks. In proactive networks data is collected at pre-specified, fixed intervals while reactive strategy requires the nodes to respond immediately ton changes in the relevant parameters of interest. We are able to combine the best features of proactive and reactive networks while minimizing their limitations to create a new type of network called a Hybrid network which not only reacts to time-critical situations, but also gives an overall picture of the network at periodic intervals in a very energy efficient manner. We introduce two new energy efficient protocols, TEEN (Threshold-sensitive Energy Efficient sensor Network protocol) for reactive networks and APTEEN (Adaptive Periodic Threshold-sensitive Energy Efficient sensor Network protocol) for hybrid networks. We have also proposed a third protocol for routing queries in hybrid networks. This protocol provides the user, flexibility to request either past, present or future data from the network in the form of historical, one-time and persistent queries respectively. We have also analytically determined the delay incurred in handling the various types of queries. To our knowledge, such an analytical modeling has been done for the first time for sensor network queries. These three protocols offer versatility to the users while consuming energy very efficiently by minimizing non-critical data transmissions. We evaluated the performance of these protocols for a simple temperature sensing application with a Poisson arrival rate for queries. In terms of energy efficiency, these protocols have been observed to outperform existing conventional warehousing sensor network protocols.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

sensor networks; wireless; query

Chowdhury, Tashnim Jabir ShovonA distributed cooperative algorithm for localization in wireless sensor networks using Gaussian mixture modeling
Master of Science, University of Toledo, 2016, Electrical Engineering
Wireless sensor networks are defined as spatially distributed autonomous sensors to monitor certain physical or environmental conditions like temperature, pressure, sound, etc. and incorporate the collected data to pass to a central location through a network. Multifarious applications including cyber-physical systems, military, eHealth, environmental monitoring, weather forecasting, etc. make localization a crucial part of wireless sensor networks. Since accuracy and low computational time of the localization, in case of some applications like emergency police or medical services, is very important, the main objective of any localization algorithm should be to attain more accurate and less time consuming scheme. This thesis presents a cooperative sensor network localization scheme that approximates measurement error statistics by Gaussian mixture. Expectation Maximization (EM) algorithm has been implemented to approximate maximum-likelihood estimator of the unknown sensor positions and Gaussian mixture model (GMM) parameters. To estimate the sensor positions we have adopted several algorithms including Broyden-Fletcher-Goldfarb-Shanno (BFGS) Quasi-Newton (QN), Davidon-Fletcher-Powell (DFP), and Cooperative Least Square (LS) algorithm. The distributive form of the algorithms meet the scalability requirements of sparse sensor networks. The algorithms have been analyzed for different number of network sizes. Cramer Rao Lower Bound (CRLB) has been presented and utilized to evaluate the performance of the algorithms. Through Monte Carlo simulation we show the superior performance of BFGS-QN over DFP and cooperative LS in terms of localization accuracy. Moreover the results demonstrate that Root Mean Square Error (RMSE) of BFGS-QN is closer to derived CRLB than both DFP and cooperative LS.

Committee:

Jared Oluoch (Committee Chair); Vijay Devabhaktuni (Committee Co-Chair); Junghwan Kim (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Localization; wireless sensor networks; Gaussian mixture modeling; EM algorithm

Katneni, NarendranadDeployment Strategies and Mechanisms for Intrusion Detection In Wireless Sensor Networks
MS, University of Cincinnati, 2012, Engineering and Applied Science: Computer Science

Wireless Sensor Networks (WSNs) play a big role in many real life scenarios and are used in a wide range of applications. That includes military, industrial and civilian security and this requires stability, performance and affordability of WSNs. Deployment schemes of sensors play an important role in the design of WSN and contribute to improving its security. There are various deployment schemes that have their own strengths and weaknesses and each one suits best for a particular set of applications.

In this thesis, we focus particularly on “Intrusion Detection”, which is an application of WSNs. We study the existing deployment schemes such as Uniform, Gaussian and identify their strengths and limitations. We then propose two new deployment techniques called Hybrid Gaussian-Ring Deployment and Reverse Gaussian Deployment. Hybrid Gaussian-Ring offers better border protection and network connectivity, whereas Reverse Gaussian performs better in protecting multiple facilities located within the area protected by the WSN.

Subsequently, we study about Regular Deployment schemes, their applications and their differences from the probabilistic deployment schemes. These are more useful when the area of deployment of WSN is more accessible and non-hostile. We then analyze the performance of various regular deployment schemes and establish which of these is best suited for intrusion detection.

Committee:

Dharma Agrawal, DSc (Committee Chair); Yizong Cheng, PhD (Committee Member); Yiming Hu, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless Sensor Networks; Intrusion Detection; Sensor Deployment; Gaussian Deployment; Regular Deployment; Security

Kulathumani, VinodkrishnanNetwork Abstractions for Designing Reliable Applications Using Wireless Sensor Networks
Doctor of Philosophy, The Ohio State University, 2008, Computer and Information Science

Applications of wireless sensor networks are moving from simply monitoring based to control based ones and from static network based to pervasive and mobility-centric ones. But while the applications are rising in scale and complexity, the underlying network is still resource-constrained and bandwidth limited, prone to contention and fading. Thus the demands of applications are growing at a faster rate than the resources in the underlying network. My thesis has addressed the challenge of reliable application design using wireless sensor networks, by the design and implementation of network abstractions that bridge the gap between the application and the network and provide performance guarantees to applications.

My dissertation considers the reliable design of 4 wireless sensor network applications: (1) distributed pursuer evader tracking with requirement of eventual catch, (2) distributed pursuer evader tracking with optimal interception, (3) object classification and track monitoring and (4) distributed control of flexible structures. For each of these applications, we come up with an appropriate design considering limitations of the underlying network and characterize the network abstractions that meet application requirements. The network abstractions are then implemented appropriately sometimes using middle-ware services running in the form distributed / centralized programs, sometimes by suitably designing the network with the right density, placement of sensors or sometimes using both.

Committee:

Anish Arora (Advisor); Prasun Sinha (Committee Member); Paul Sivilotti (Committee Member); Tamal Dey (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless sensor networks; middleware services; network abstractions; application; tracking; classification; distributed control

Thomas, Richie JEXPERIMENTAL EVALUATION OF EMULI: A TOOL FOR SENSOR ABSTRACTION IN WIRELESS SENSOR NETWORKS
MS, Kent State University, 2007, College of Arts and Sciences / Department of Computer Science
Wireless sensor networks have found a wide range of applications – from environmental monitoring to automation systems. Developing applications using wireless sensor platforms involves intensive experimentation and testing. Building the experimental system with actual physical components like sensors may not be practical due to high cost or unavailability of the sensors. This problem can be solved by implementing virtual sensors that mimic the real sensors but which are implemented in software. The virtual sensors are abstractions of the physical sensors. They mimic the real sensors in all their functionality but is available at a fraction of the cost. In this thesis we describe Emuli — a method of effectively substituting sensor data by synthetic data on physical wireless nodes (motes). The sensor application is oblivious to this substitution. Emuli generates data on demand from the application. The replies are based on the sensor model which is driven by the data preloaded to the mote before the experiment. Since the preloaded data is an approximation of the sensor behavior rather than raw sensor readings, it is rather compact. Therefore it can be stored in the memory of each individual device. The emulated stimuli can be synchronized and coordinated across multiple motes which allows to experiment with distributed events. Emuli abstracts the sensing component of a complete application and allows the experimenter to focus only on processing and transport function of a wireless sensor networks. We demonstrate statistical and deterministic sensor models. We showcase the use of Emuli in a light measurement and industrial automation system implementation.

Committee:

Mikhail Nesterenko (Advisor)

Subjects:

Computer Science

Keywords:

SENSOR; motes; EMULI; node; sensor value; SENSOR NETWORKS; WIRELESS SENSOR

Gaur, AmitSecured Communication in Wireless Sensor Network (WSN) and Authentic Associations in Wireless Mesh Networks
MS, University of Cincinnati, 2010, Engineering and Applied Science: Computer Science
Wireless sensors are low power devices with small transmission range, restricted computation power, limited amount of memory and with portable power supply. Wireless Sensor Network (WSN) is a collection of such sensors where the number of sensors can vary from few hundreds to thousands. Performing secure pair-wise communication between sensors is a really difficult task due to inherent characteristics such as lack of any fixed infrastructure. As memory and power consumption are most stringent requirements for these devices, use of conventional techniques for secured communication are totally out of question. This thesis introduces scheme that enables a complete pair-wise secure connectivity between any two adjacent sensor nodes in spite of using small key ring (KR) for sensors. The Proposed Scheme (ELKPD) doesn't require any additional hardware while providing keys to the sensors irrespective of their location. Also, proposed scheme is easily scalable which allows enables addition of sensor nodes without any computational or hardware overheads. Due to the varying degree of mobility of Mesh Clients has provided much more flexibility in Wireless Mesh Networks. And establishing an Authentic Association among entities is a non -trivial problem. In this thesis, we introduce a Polynomial Based scheme which not only provides high pair-wise connectivity, low communication and storage overhead and high scalability but also makes on the fly Authentic Association feasible. The proposed scheme is also observed to be resilient against both the traffic analysis and the node capture attacks.

Committee:

Dharma Agrawal, DSc (Committee Chair); Raj Bhatnagar, PhD (Committee Member); Carla Purdy, C, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

security;wireless sensor networks;key-predistribution;wireless mesh networks;bi-variate polynomials

Zheng, ZizhanSparse Deployment of Large Scale Wireless Networks for Mobile Targets
Doctor of Philosophy, The Ohio State University, 2010, Computer Science and Engineering

Deploying wireless networks at large scale is challenging. Despite various effort made in the design of coverage schemes and deployment algorithms with static targets in mind, how to deploy a wireless network to achieve a desired quality of service for mobile targets moving in a large region without incurring prohibitive cost largely remains open. To address this issue, this dissertation proposes Sparse Coverage, a deployment scheme that provides guaranteed service to mobile targets while trading off service quality with cost in a deterministic way.

The first part of this dissertation discusses two sparse coverage models for deploying WiFi access points (APs) along a city-wide road network to provide data service to mobile vehicles. The first model, called Alpha Coverage, ensures that a vehicle moving through a path of length α is guaranteed to have a contact with some AP. This is the first partial coverage model (in contrast to the more expensive full coverage model) that provides a performance guarantee to disconnection-tolerant mobile users. We show that under this general definition, even to verify whether a given deployment provides Alpha Coverage is co-NPC. Thus, we propose two practical metrics as approximations, and design efficient approximation algorithms for each of them. The concept of Alpha Coverage is then extended by taking connectivity into account. To characterize the performance of a roadside WiFi network more accurately, we propose the second sparse coverage model, called Contact Opportunity, which measures the fraction of distance or time that a mobile user is in contact with some AP. We present an efficient deployment method that maximizes the worst-case contact opportunity under a budget constraint by exploiting submodular optimization techniques. We further extend this notion to the more intuitive metric -- average throughput -- by taking various uncertainties involved in the system into account.

The second part of this dissertation studies sparse deployment techniques for placing sensor nodes in a large 2-d region for tracking movements. We propose a sparse coverage model called Trap Coverage, which provides a bound on the largest gap that a mobile target, e.g., an intruder or a dynamic event, is missed by any sensor node. In contrast to the current probabilistic partial coverage models, this is the first 2-d coverage model that can trade off the quality of tracking with network lifetime in a deterministic way. For an arbitrarily deployed sensor network, we propose efficient algorithms for determining the level of Trap Coverage even if the sensing regions have non-convex or uncertain boundaries. We then discuss a roadmap assisted geographic routing protocol to support efficient pairwise routing in large sensor networks with holes, which embodies a novel hole approximation technique and makes desired tradeoff between route-stretch and control overhead.

Committee:

Prasun Sinha (Advisor); Ness Shroff (Committee Member); Yusu Wang (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless networks; sensor networks; coverage; sparse coverage; approximation algorithms

Ramakrishnan, NaveenDistributed Learning Algorithms for Sensor Networks
Doctor of Philosophy, The Ohio State University, 2010, Electrical and Computer Engineering

Wireless sensor networks have received significant attention in the last decade owing to their widespread use not only in monitoring the physical world but also in surveillance. The energy and communication constraints of sensor nodes, coupled with distributed processing of sensed signals, lead to challenges in developing effective methods to perform desired inference tasks such as object detection or classification. Further, the lack of well-calibrated sensors is a major obstacle for the rapid deployment of sensor networks.

This dissertation develops gossip-based learning algorithms for distributed signal processing in sensor networks. In gossip-based algorithms, sensor nodes share information with local neighbors to converge upon common knowledge about the sensed environment. Gossip-based methods allow for manageable communication among energy-constrained nodes and also accommodate changing network communication topologies.

We consider three related problems and develop gossip-based processing solutions. We first consider the problem of joint signature estimation and node calibration using distributed measurements over a large-scale sensor network. We develop a new Distributed Signature Learning and Node Calibration algorithm, called D-SLANC, which estimates the signature of a commonly-sensed source signal and simultaneously estimates calibration parameters local to each sensor node. The approach we take is to model the sensor network as a connected graph and make use of the gossip-based distributed consensus to update the estimates at each iteration of the algorithm. We prove convergence of the algorithm to the centralized data pooling solution. We also compare its performance with the Cramér-Rao bound (CRB), and study the scaling performance of both the CRB and the D-SLANC algorithm.

Secondly, we develop a gossip-based algorithm for distributed 1-optimization in a large-scale sensor network setting. Specifically, we consider sensor nodes which can measure only a part of the entire measurement vector. We formulate the 1-optimization problem as quadratic optimization and develop a distributed, gossip-based algorithm using the projected-gradient approach. We analyze the performance of the proposed algorithm using synthetic data and compare it with a standard 1 solver.

Third, we consider the problem of distributed classifier learning in a large-scale sensor network setting. We adopt a machine learning approach to the problem and develop a distributed, gossip-based algorithm that learns the optimal (large-margin) hyperplane separating the two classes, using the projected-gradient approach. We illustrate the performance of the proposed algorithm using both synthetic and real-world datasets.

Committee:

Randolph Moses (Advisor); Emre Ertin (Advisor); Lee Potter (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Sensor Networks; Machine Learning; Gossip; Distributed algorithms; Classification

Mishra, AmitabhModeling and Performance Evaluation of Wireless Body Area Networks for Healthcare Applications
PhD, University of Cincinnati, 2015, Engineering and Applied Science: Computer Science and Engineering
Wireless Body Area Network (WBAN) is a low-power Personal Area Network involving sensor nodes (SNs) that sense and relay physiological data to a central station. WBANs are new and still evolving. We try to address three open research areas involving WBANs. The limited energy budget in WBANs necessitates energy conservation to prolong the network lifetime. The first challenge we try to address is related to improvement of the lifetime of a WBAN, given the small sizes of body sensor nodes (SNs) and the limited battery power that they run on. We proposed a dual-prediction framework for improvement of network lifetime. The framework allows for minimizing data transmission involving four important body parameters by reconstructing their information by time series prediction at reception. A sample elimination algorithm further optimizes the framework performance. We enhanced the framework by reducing the sampling frequency and implementing the algorithm on top, increasing the network lifetime further. The missing samples were reconstructed by interpolation at the receiver. We probed the effects of adaptive sampling and evaluated the increase in battery lifetime in WBANs. We then tried to test the behavior of a WBAN in the presence of other WBANs around it and check the issues faced by WBANs. Wireless systems can face severe interference problems if they use the same communication channels at a time. There are issues related to data routing because the critical nature of WBAN data requires assured communication of body data. For optimum network utilization, efficient scheduling of transmissions in multiple co-existing WBANs is important in order to avoid intra and inter-WBAN interference and for a graceful coexistence. We propose that inter-WBAN interference can be avoided by a QoS based MAC scheduling approach and that intra-WBANs interference can be circumvented by fuzzy scheduling of intra-WBAN transmissions. We also propose to use interference to the benefit of WBANs through a framework in which neighboring WBANs communicate for cooperative packet routing. This lets the WBANs use some spare transmission iii slots from their neighbor WBANs when required. This can happen when a WBAN with more or sudden, emergency data is strapped for transmission slots while its neighbor has some to spare. A routing tree is created using a weighted two-pass algorithm involving an assisting WBAN that can accommodate routing requests from its neighbor WBAN. We further evaluated the possibility of relaying data from a mobile WBAN through small scale networks for voice communication. The scheme uses dynamic virtual cells that grow and shrink in order to provide uninterrupted service, while reducing handovers. Although wireless systems are reliable in conveying sensor data but their use for control applications is still nascent. We tried to probe if WSNs in general or WBANs in particular could be used for wireless control. We have evaluated the performance of ON-OFF control involving a wireless sensor network for musical entertainment applications. We further extended our work and tested the feasibility of control in WSNs and in more critical real life applications in WBANs.

Committee:

Dharma Agrawal, D.Sc. (Committee Chair); Raj Bhatnagar, Ph.D. (Committee Member); Prabir Bhattacharya, Ph.D. (Committee Member); Chia Han, Ph.D. (Committee Member); Marepalli Rao, Ph.D. (Committee Member)

Subjects:

Computer Science

Keywords:

Wireless Body Area Networks;Wireless Body Sensor Networks;Energy Efficiency;QoS based MAC;Interference in WBANs

Abuaitah, Giovani RimonANOMALIES IN SENSOR NETWORK DEPLOYMENTS: ANALYSIS, MODELING, AND DETECTION
Doctor of Philosophy (PhD), Wright State University, 2013, Computer Science and Engineering PhD
A sensor network serves as a vital source for collecting raw sensory data. Sensor data are later processed, analyzed, visualized, and reasoned over with the help of several decision making tools. A decision making process can be disastrously misled by a small portion of anomalous sensor readings. Therefore, there has been a vast demand for mechanisms that identify and then eliminate such anomalies in order to ensure the quality, integrity, and/or trustworthiness of the raw sensory data before they can even be interpreted. Prior to identifying anomalies, it is essential to understand the various anomalous behaviors prevalent in a sensor network deployment. Therefore, we begin this work by providing a comprehensive study of anomalies that exist in a sensor network deployment, or are likely to exist in future deployments. After this thorough systematic analysis, we identify those anomalies that, in fact, hinder the quality and/or trustworthiness of the collected sensor data. One approach towards the reduction of the negative impact of misleading sensor readings is to perform off-line analysis after storing a large amount of sensor data into a centralized database. To this end, in this work, we propose an off-line abnormal node detection mechanism rooted in machine learning and data mining. Our proposed mechanism achieves high detection accuracy with low false positives. The major disadvantage of a centralized architecture is the tremendous amount of energy wasted while communicating the sensor readings. Therefore, we further propose an on-line distributed anomaly detection framework that is capable of accurately and rapidly identifying data-centric anomalies in-network, while at the same time maintaining a low energy profile. Unlike previous approaches, our proposed framework utilizes a very small amount of data memory through on-line extraction of few statistical features over the sensor data stream. In addition, previous detection mechanisms leverage sensor datasets obtained from an earlier deployment or use synthetic data to test their effectiveness. Our framework, on the other hand, has been entirely implemented in TinyOS as a prototype readily deployable into existing sensor networks, alongside other essential protocols such as sensor data collection protocols. An advantage of our system is the fact that it relies on supervised learning. Supervised machine learning algorithms usually achieve higher accuracy than their unsupervised counterparts given a highly representative common ground truth. Thus, in this work, we also design highly expressive anomaly models that may be leveraged to inject anomalous readings into existing sensor network deployments. In order to do so, we have developed a tool called SNMiner which enables us not only to inject anomalies into a network of sensors, but also to extract important statistical features and evaluate the accuracy of a number of supervised machine learning algorithms.

Committee:

Bin Wang, Ph.D. (Advisor); Yong Pei, Ph.D. (Committee Member); Keke Chen, Ph.D. (Committee Member); Shu Schiller, Ph.D. (Committee Member)

Subjects:

Computer Engineering; Computer Science

Keywords:

anomaly detection; online anomaly detection; anomaly analysis; anomaly modeling; SNMiner; ABANDON; POND; sensor network deployments; wireless sensor networks

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