Search Results (1 - 8 of 8 Results)

Sort By  
Sort Dir
 
Results per page  

Sridharan, MukundanDesign of Mobile and Static Sensor Fabrics
Doctor of Philosophy, The Ohio State University, 2011, Computer Science and Engineering

Over the last few years, two fundamental changes have happened in the domain of Wireless Sensor Networks (WSN). One, the applications have ceased to be edge-alone and have morphed into a edge-enterprise co-design. Two, sensor networks are beginning to be shared by a number of stake holders, with varied requirements. This translates into three key requirements for today's WSNs. One, the networks to be designed should be customizable and repurposeable on short notice. Two, the networks should be sliceable--the ability to deploy and run multiple applications simultaneously. Three, the networks need to be designed in such a way as to enable interaction, collaboration and federation with other networks or agents outside of the network to achieve some common goal. This has led to the re-examination of the application development model for WSNs.

This dissertation proposes an architecture called the fabric model for designing WSN as generic sensing networks, on which applications can be tailored. The model focuses on standardizing services and APIs that are common to most sensor fabrics, so that the common services can be reused across fabrics.

We illustrate the usefulness of the fabric model by specifying and building three different fabrics, but by reusing a number of common services. The three fabrics, Kansei--a sensor testbed with a wired control channel, PeopleNet--a mobile wireless network and VillageNet--an intermittently-connected mobile network, use the same fault-tolerant fabric manager and I/O services. As one of the key contributions we present the architecture for a fault-tolerant, scalable and autonomous fabric manager that can manage thousands of sensor nodes.

While we reuse a number of services in PeopleNet and VillageNet from Kansei, a few significant challenges remain in designing mobile WSN fabrics. An energy constrained multi-hop mobile network, such as, PeopleNet and VillageNet, needs an efficient and reliable routing protocol. Thus, we make two key contributions in the mobile routing space. We have designed & implemented the Asymmetric Event-driven Routing (AER) service, which provides energy efficient messaging service in a slowly mobile network, and the Reliable Energy Aware Predictive Routing (REAPER) service, which provides end-to-end messaging for intermittently-connected mobile networks.

The fabric model provides a number of advantages in designing customizable fabrics and its services based design lends itself to WSN federations naturally. But, a number of other challenges remain in federating WSN fabrics. We present KanseiGenie, a GENI-compliant software architecture for federating geographically separated sensor fabrics and to provide the user with a common interface to program across the federated fabrics. KansiGenie, builds on top of the fabric model and tackles issues related to resource and experiment specification in federating sensor fabrics. We also demonstrate through WEAVE--a domain specific service--how a federated application can be stitched using multiple sensor fabrics.

As sensor networks become ubiquitous and federated, we hope and believe that our work in this dissertation will serve as one of the cornerstones, which will encourage further research in the design and integration of sensor networks.

Committee:

Anish Arora, PhD (Committee Chair); Prasu Sinha, PhD (Committee Member); Rajiv Ramnath, PhD (Committee Member)

Subjects:

Communication; Computer Engineering; Computer Science; Experiments; Information Science

Keywords:

WSN; sensor fabric; fabric model; Asymmetric Event-Driven Routing; DTN; REAPER; invariant-based fault model; autonomic manager; WSN federation; GENI

Fiske, Robert M.Implementation and Evaluation of a TDMA Based Protocol for Wireless Sensor Networks
Master of Science in Software Engineering, Cleveland State University, 2010, Fenn College of Engineering
When evaluating MAC layer network protocols for wireless sensor networks performing simulations of a protocol’s operation can provide great insight into the performance of the protocol. In order to prove that a protocol will work in a real setting and not just at the theoretical level, however, there is no substitute for evaluation with a physical implementation. This thesis discusses a physical implementation and evaluation of the Many-to-One-Sensor-to-Sink (MOSS) MAC layer protocol for sink based wireless sensor networks using the MAC Layer Architecture for TinyOS. MOSS is a Time Division Multiple Access (TDMA) based protocol first proposed in an earlier work. MOSS aims to utilize the strengths and alleviate the weaknesses of TDMA. In addition to discussing and evaluating the physical MOSS implementation, the process of developing MAC layer protocol implementations with MLA is also discussed.

Committee:

Chansu Yu, PhD (Committee Chair); Wenbing Zhao, PhD (Committee Member); Nigamanth Sridhar, PhD (Committee Member)

Subjects:

Computer Engineering; Engineering

Keywords:

TDMA; WSN; Wireless Sensor Network; MAC; MLA; Mac Layer Architecture; MOSS; Many-to-One-Sensor-to-Sink;

WANG, XIAODONGQoS ISSUES AND QoS CONSTRAINED DESIGN OF WIRELESS SENSOR NETWORKS
PhD, University of Cincinnati, 2006, Engineering : Computer Science and Engineering
Most existing research in wireless sensor networks (WSNs) has been focused on proposing protocols to facilitate either energy effient communication or sensing operation in WSNs. We believe that there exist fundamental limits in the operations and the parameters of WSNs. Characterizing these fundamental limits, establishing the relationships between the parameters and the WSN performance, and identifying the tradeoffs among different performance measures can provide us insights in designing sensor networks. In this dissertation, the QoS properties of WSNs, including the coverage, reachability, and delay, are analyzed in an analytical framework. How the network parameters, such as the node density, sensing range, transmission range, impact the aforementioned QoS properties are investigated by abstracting the randomly deployed WSNs as random geometric graphs. Both homogenous and heterogenous sensor networks are addressed. Based on the analytical model, optimal sensor network parameters can be chosen to improve the network performance while achieving pre-specified QoS constraints. Besides this abstraction, practical issues affecting the QoS performance of WSNs are also examined by doing extensive simulations in this dissertation. Specifically, results are obtained for the QoS properties in the flooding of WSN when a cross-layer approach is adopted, and other practical issues such as channel fading and MAC layer contention are taken into account. The results show that exchanging more information across the layers can help improve effciency of the protocol. It is further shown that wireless fading helps to reduce the hop count, although it makes the transmission range less predictable and limits the improvement in the performance of such cross-layer design in WSNs.

Committee:

Dr. Dharma Agrawal (Advisor)

Subjects:

Computer Science

Keywords:

coverage; connectivity; delay; energy efficiency; QoS; WSN

Abuaitah, Giovani RimonTrusted Querying over Wireless Sensor Networks and Network Security Visualization
Master of Science in Computer Engineering (MSCE), Wright State University, 2009, Computer Engineering

Wireless sensor networks (WSNs) as an emerging technology faces numerous challenges. Sensor nodes are usually resource constrained. Sensor nodes are also vulnerable to physical attacks or node compromises. Answering queries over data is one of the basic functionalities of WSNs. Both resource constraints and security issues make designing mechanisms for data aggregation particularly challenging. In this thesis, we first explore the various security techniques for data aggregation in WSNs then we design and demonstrate the feasibility of an innovative reputation-based framework rooted in rigorous statistical theory and belief theory to characterize the trustworthiness of individual nodes and data queries in WSNs.

Detecting security vulnerabilities is an imperative task. Visualization techniques have been developed over decades and are powerful when employed in the field of network security. In this thesis, we present a novel security visualization tool called “SecVizer”.

Committee:

Bin Wang, PhD (Advisor); Yong Pei, PhD (Committee Member); Thomas Wischgoll, PhD (Committee Member)

Subjects:

Computer Science

Keywords:

trusted querying; spatial and temporal correlated wireless sensor network; WSN security; node compromise; network security visualization; parallel coordinate plot; SecVizer

Reddy, Prashanth G.EFFICIENT TIME OF ARRIVAL CALCULATION FOR ACOUSTIC SOURCE LOCALIZATION USING WIRELESS SENSOR NETWORKS
Master of Science in Electrical Engineering, Cleveland State University, 2011, Fenn College of Engineering
Acoustic source localization is a very useful tool in surveillance and tracking applications. Potential exists for ubiquitous presence of acoustic source localization systems. However, due to several significant challenges they are currently limited in their applications. Wireless Sensor Networks (WSN) offer a feasible solution that can allow for large, ever present acoustic localization systems. Some fundamental challenges remain. This thesis presents some ideas for helping solve the challenging problems faced by networked acoustic localization systems. We make use of a low-power WSN designed specifically for distributed acoustic source localization. Our ideas are based on three important observations. First, sounds emanating from a source will be free of reflections at the beginning of the sound. We make use of this observation by selectively processing only the initial parts of a sound to be localized. Second, the significant features of a sound are more robust to various interference sources. We perform key feature recognition such as the locations of significant zero crossings and local peaks. Third, these features which are compressed descriptors, can also be used for distributed pattern matching. For this we perform basic pattern analysis by comparing sampled signals from various nodes in order to determine better Time Of Arrivals (TOA). Our implementation tests these ideas in a predictable test environment. A complete system for general sounds is left for future work.

Committee:

Nigamanth Sridhar, PhD (Committee Chair); Murad Hizlan, PhD (Committee Member); Wenbing Zhao, PhD (Committee Member)

Subjects:

Electrical Engineering

Keywords:

Localization;TOA;TDOA;Wireless Sensor Networks;WSN;Acoustic;Time of Arrival;Acoustic Source Localization

CHENG, YISecurity Mechanisms for Mobile Ad Hoc and Wireless Sensor Networks
PhD, University of Cincinnati, 2008, Engineering : Computer Science and Engineering

Wireless Ad Hoc Networks have emerged as an advanced networking paradigm based on collaborative efforts among multiple self-organized wireless communication devices. Without the requirement of a fixed infrastructure support, wireless ad hoc networks can be quickly deployed anywhere at any time when needed. The decentralized nature, minimal configuration and quick deployment of wireless ad hoc networks make them suitable for various applications, from disaster rescue, target tracking to military conflicts. Wireless ad hoc networks can be further categorized into mobile ad hoc networks (MANETs), wireless sensor networks (WSNs), and wireless mesh networks (WMNs) depending on their applications.

Security is a big challenge in wireless ad hoc networks due to the lack of any infrastructure support, dynamic network topology, shared radio medium, and resource-constrained wireless users. Most existing security mechanisms applied for the Internet or traditional wireless networks are neither applicable nor suitable for wireless ad hoc network environments. In MANETs, routing security is an extremely important issue, as the majority of the standard routing protocols assume non-hostile environments. Once deployed in a hostile environment and working in an unattended mode, existing routing protocols are vulnerable to various attacks. To address these concerns, we propose an anonymous secure routing protocol for MANETs in this dissertation, which can be incorporated with existing routing protocols and achieve enhanced routing security with minimum additional overheads.

In WSNs, key distribution and management is the core issue of any security approaches. Due to extremely resource-constrained sensor nodes and lack of any infrastructure support, traditional public-key based key distribution and management mechanisms are commonly considered as too expensive to be employed in WSNs. In this dissertation, we propose two efficient pairwise key pre-distribution and management mechanisms for both distributed and hierarchical large-scale WSNs, which enable establishing secure links between any two sensor nodes located within their communication range. As we know, sensing and communication are two fundamental characteristics of WSNs, and they cannot be addressed separately. Existing work on sensing coverage mainly focus on how to use the minimum number of sensors to achieve a required coverage, while security constraints are not sufficiently addressed. We propose an effective key distribution approach for randomly deployed WSNs, based on random graph theory and a realistic random key pre-distribution mechanism, in order to achieve both robust sensing coverage and secure connectivity simultaneously in a hostile deployment environment.

Committee:

Dharma Agrawal (Committee Chair); Jerome Paul (Committee Member); Wen-Ben Jone (Committee Member); Chia-Yung Han (Committee Member); Ernest Hall (Committee Member)

Subjects:

Communication; Computer Science

Keywords:

Wireless Ad Hoc Network; Mobile Ad Hoc Network (MANET); Wireless Sensor Network (WSN); Routing; Security; Cryptography; Key Management; Distributed Wireless Network; Hierarchical Wireless Network; Sensing Coverage; Secured Connectivity

Yan, ChunpengAsynchronous Localization for Wireless Sensor Networks
PhD, University of Cincinnati, 2009, Engineering : Electrical Engineering

Large clock offsets and clock drifts impose many difficulties on wireless sensor network localization. Radio frequency (RF) ranging methods such as time-of-arrival (TOA) and time-difference-of-arrival (TDOA) are difficult to be implemented in such cases due to tight timing synchronization requirements. The differential-time- difference-of-arrival (dTDOA) method is proposed to overcome the problem of asynchronous clock offsets and clock drifts.

Using the underlying dTDOA method, this thesis investigates two kinds of sensor localization applications that differ in system settings and RF ranging signals: wireless sensor network self-localization and non-GNSS (Global Navigation Satellite System) localization using signals of opportunity.

For wireless sensor network self-localization, a number of theorems and a set of methods for determination of relative locations of all sensors are proposed. A linearization method and maximum likelihood estimation (MLE) methods for sensor location estimation are derived, and the linear approximate solution given by the linearization method is used to initialize the MLEs. The methods can achieve sensor localization using a single round of asynchronous TOA measurements, and thus greatly reduces the communication burden and timing constraint.

Non-GNSS localization techniques that use signals of opportunity (e.g. TV/AM broadcast signals with known locations) without aid of satellite-based location systems (e.g. GPS) are promising, since they use readily available strong signals in a wide frequency range that are not susceptible to blockage or jamming. However, problems such as large asynchronous clock offsets among receivers and large broadcast signal frequency offsets arise because commercial broadcast signals are not dedicated for ranging purposes. The dTDOA positioning method is used to overcome the problems of biased broadcast signal frequencies and asynchronous receiver clocks. The proposed method eliminates the need for synchronous receiver clocks and mitigates the effects of broadcast signal frequency offsets. Furthermore, a method for TOA estimation using digital TV signals in multipath propagation is proposed. This method extends the classical ESPRIT method by integrating an optimal threshold determination algorithm and is capable of mitigating the effects of multipath and non-line-of-sight (NLOS) in broadcasting channels, provided that the statistical characteristics of the multipath and NLOS channel are known a priori.

The thesis also proposes a robust non-line-of-sight (NLOS) multipath mitigation method for TOA estimation when the statistical characteristics of the multipath and NLOS channel are unknown a priori, based on a technique that consists of correlation followed by thresholding. This technique is widely used to mitigate multipath effects, especially in the presence of NLOS effects. However, in practice, an accurate threshold that the technique relies on is difficult to obtain, since optimizing the threshold requires prior knowledge of channel statistics and signal/noise power, which are not always known a priori nor are easy to estimate. The proposed method does not rely on such prior knowledge and is robust against an inaccurate threshold.

Theoretical analyses and computer simulations are presented to support the performance of the proposed methods.

Committee:

H. Howard Fan, PhD (Committee Chair); Ali Minai, PhD (Committee Member); Dharma Agrawal, PhD (Committee Member); Qing-An Zeng, PhD (Committee Member); Patrick Garrett, PhD (Committee Member)

Subjects:

Electrical Engineering

Keywords:

TOA; TDOA; localization; GPS; WSN; non-line-of-sight

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