Engineering Commons^™

Vcare: A Personal Emergency Response System To Promote Safe And Independent Living Among Elders Staying By Themselves In Community Or Residential Settings, Priyankar Bhattacharjee

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

‘Population aging’ is a growing concern for most of us living in the twenty first century, primarily because many of us in the next few years will have a senior person to care for - spending money towards their healthcare expenditures AND/OR having to balance a full-time job with the responsibility of care-giving, travelling from another city to be with this elderly citizen who might be our parent, grand-parent or even community elders. As informal care-givers, if somehow we were able to monitor the day-to-day activities of our elderly dependents, and be alerted when wrong happens to them that would …

Energy Harvesting And Storage: The Catalyst To The Power Constraint For Leveraging Internet Of Things (Iot) On Trains, Kelechi Nwogu

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

The success of Wireless Sensor Networks is heavily constrained by its reliance on storage technology like batteries, which are a finite resource. Whilst the number of transistors in an IC doubles every 18 months, the energy density of batteries is relatively flat during the same time period. This is a key challenge in leveraging the Internet of Things on trains.

The gravity of this problem is increased by an order of magnitude when the network is to be scaled up to hundreds or thousands of nodes. Comprehensive research and development efforts have been devoted to building ultra-low power sensors. These …

A Performance Study Of Genetic Algorithm-Assisted Beamforming In Distributed Cognitive Radio Networks, Andrew Minturn

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Cognitive Radio (CR) is a technology that has gained much interest recently due to the increasing scarcity of the radio frequency spectrum. Large portions of the radio frequency spectrum are licensed to users who then have exclusive access to the bandwidth, and unlicensed bands can be a challenge to use due to interference from unlicensed users. Despite the seeming scarcity, tests of bands allocated by the Federal Communications Committee (FCC) to licensed and unlicensed user have shown that many are underutilized and often unoccupied by the user to whom they are licensed. CR aims to exploit this unused spectrum and …

Performance Analysis Of Mobile Ad-Hoc Routing Protocols By Varying Mobility, Speed And Network Load, Nilotpal Sarmah

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

One of the most promising network that has emerged from the technology world is the mobile ad-hoc network or MANET. It is a type of multi-hop network. Wireless by nature, MANETs do not have a specific network infrastructure. It is a collection of wireless mobile devices that communicate with each other without the help of any third party backbone like a base-station or a router. It can be hard to imagine how every node in this type of network communicate with one another without having a router. In MANETs, nodes change locations with time, configure themselves and get the information …

Security Analysis Of Phasor Measurement Units In Smart Grid Communication Infrastructures

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Phasor Measurement Units (PMUs), or synchrophasors, are rapidly being deployed in the smart grid with the goal of measuring phasor quantities concurrently from wide area distribution substations. By utilizing GPS receivers, PMUs can take a wide area snapshot of power systems. Thus, the possibility of blackouts in the smart grid, the next generation power grid, will be reduced. As the main enabler of Wide Area Measurement Systems (WAMS), PMUs transmit measured values to Phasor Data Concentrators (PDCs) by the synchrophasor standard IEEE C37.118. IEC 61850 and IEC 62351 are the communication protocols for the substation automation system and the security …

A Study On Countermeasures Against Steganography: An Active Warden Approach, Qilin Qi

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Digital steganography is a method used for hiding information in digital images. It can be used for secure communication. There have been many robust digital steganography methods invented in recent decades. The steganographic message can be inserted in multimedia cover signal such as audio, image and video. However, this technique also may be used by malicious users to transmit dangerous information through the Internet beyond the control of security agencies. How to detect and/or block potentially dangerous information transmission on the Internet through billions of multimedia files while not affecting innocent multimedia communications becomes a challenging problem. Existing steganalysis methods …

Adaptive Co-Scheduler For Highly Dynamic Resources, Kartik Vedalaveni

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

There are many kinds of scientific applications that run on high throughput computational (HTC) grids. HTC may utilize clusters opportunistically, only running on a given cluster when it is otherwise idle. These widely dispersed HTC clusters are heterogeneous in terms of capability and availability, but can provide significant computing power in aggregate. The scientific algorithms run on them also vary greatly. Some scientific algorithms might use high rates of disk I/O and some might need large amounts of RAM. Most schedulers only consider cpu availability, but unchecked demand on these associated resources that aren’t managed by resource managers may give …

Cross-Layer Optimized Wireless Video Surveillance, Yun Ye

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

A wireless video surveillance system contains three major components, the video capture and preprocessing, the video compression and transmission over wireless sensor networks (WSNs), and the video analysis at the receiving end. The coordination of different components is important for improving the end-to-end video quality, especially under the communication resource constraint. Cross-layer control proves to be an efficient measure for optimal system configuration. In this dissertation, we address the problem of implementing cross-layer optimization in the wireless video surveillance system.

The thesis work is based on three research projects. In the first project, a single PTU (pan-tilt-unit) camera is used …

Design And Implementation Of A Hybrid Technology Networking System, Sushanta Mohan Rakshit

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

The safety of rail transport has always been the top priority for the Federal
Railroad Administration (FRA). Legacy technology, like wayside monitoring, is still
in place and is largely relied upon for detection of faults. Modern technology like
Radio Frequency Identification (RFID) has been introduced recently. However, this
is largely used to detect a particular railcar rather than to monitor it for problems.
Wireless Sensor Network (WSN) technology is being evaluated by the railroads for real-time or near real-time monitoring of the status of railcars for timely response to problems and also for trend analysis.

ZigBee has been the networking …

Analysis Of The Feasibility Of Utilizing Wakeup Radios To Optimize Energy And Latency Performance Of Wireless Sensor Networks, Benjamin D. Parks

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Wireless sensor networks (WSNs) have the potential to radically improve our lives by pervasive environmental monitoring in many applications. However, there are many applications that would be ideal for WSNs, but where reportable events occur with long (days, weeks) or unpredictable durations between occurrences. These uses are hampered by the high energy and latency costs of always-on and periodic wakeup networks, which waste energy on node synchronization and idle monitoring of the RF channel, and exhibit unacceptably high latency for urgent events, e.g., alarms. This thesis proposes, designs, assembles and tests, in a multi-hop WSN test bed, a wakeup receiver …

An Ultra-Low Power Communication Protocol For A Self-Powered Wireless Sensor Based Animal Monitoring System, Tao Ma

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

To prevent and control the outbreak of contagious animal disease, many countries have developed animal identification and tracking systems. However, the current animal identification and tracking system, which is based on passive RFID technology, has many limitations such as the short communication range and incapability of automatically monitoring the animal. To overcome these limitations, our Advanced Telecommunications Engineering Laboratory (TEL) in Department of Computer and Electronics Engineering (CEEN), University of Nebraska-Lincoln took the mission of developing a more advanced monitoring system for animal identification and tracking. This dissertation work as a part of this mission was focusing on developing an …

Energy Efficiency Analysis And Optimization On Mobile Video Wireless Delivery, Jianxin Sun

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Micro-electronic industry has been boosting the capability of wireless mobile devices on full-scale. However, battery, as the only power source of most mobile devices, is experiencing a relatively slow development. Therefore, how to optimally utilize the limited battery energy on mobile devices under a predefined performance requirement becomes a critical issue. On the other hand, it is still unclear that how the battery capacity consumption is allocated on different working pattern of a specific video codec under various tempo-spatial scales and parameters, which has posed a design challenge on power management on multimedia communication system. Furthermore, an optimization method is …

A Multi-Modal Sensing And Communication Platform For Continental-Scale Migratory Bird Tracking, David J. Anthony

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

This thesis presents a novel platform for tracking migratory birds on a continental scale. Cellular technology is used to augment the short-range radios that have traditionally been used in wireless sensor networks. The platform utilizes multiple sensors, including a GPS and solid state compass. By using these sensors, the platform is capable of not only tracking a bird’s migration path, but also provides information on a bird’s behavior during its life-cycle. Testing methodology utilizing simulations and aspect-oriented programming is used to reveal faults in the platform prior to deployment on wild animals. In collaboration with the International Crane Foundation, and …

A Study Of Correlations Between The Definition And Application Of The Gene Ontology, Yuji Mo

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

When using the Gene Ontology (GO), nucleotide and amino acid sequences are annotated by terms in a structured and controlled vocabulary organized into relational graphs. The usage of the vocabulary (GO terms) in the annotation of these sequences may diverge from the relations defined in the ontology. We measure the consistency of the use of GO terms by comparing GO's defined structure to the terms' application. To do this, we first use synthetic data with different characteristics to understand how these characteristics influence the correlation values determined by various similarity measures. Using these results as a baseline, we found that …

A Novel Telecommunications-Based Approach To Mathematical Modeling Of Hiv Infection, Aaron T. Sharp

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

It is well known that biological systems utilize communication in some form, one prolific example of this is the propagation of HIV (Human Immunodeficiency Virus) in the human body. By modeling HIV infection as a communication system, we hope to gain a unique insight into HIV and biological communication systems in general. Such a model would provide researchers a platform for experimenting and simulating various biological communication systems. We have previously developed a layered communication protocol for interpreting biological communication systems using telecommunications paradigms and will apply said model to HIV proliferation. We will also demonstrate the effectiveness of the …

A Quantitative Performance Analysis Of 2.5 Ghz And 3.65 Ghz Mobile Wimax, Pradhumna L. Shrestha

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Mobile WiMAX has emerged as a prime contender for the de-facto ITU’s 4G standard. It provides high data rate with large coverage and vehicular mobility support. It has been, and is being, widely deployed in diverse applications like video streaming, broadcasting and data service. The FCC (Federal Communications Commission) issues licenses to operate Mobile WiMAX services in several spectrums, among which 2.5 GHz and 3.65 GHz are the most common. Because the 2.5 GHz spectrum suffers the least propagation losses, it has been widely applied commercially. For this reason, academic and industrial researchers have given it particular attention. However, in …

Study Of Cellular Phone Detection Techniques, Nicholas W. Scott

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

This thesis studies techniques for detecting cellular phones. It examines existing technology currently available on the open market, an existing design that utilizes mostly discrete components, and a design approach using a down converter in conjunction with a bandpass filter.

The existing technologies available on the open market are examined and discussed. These technologies are not adequate, because they are inaccurate and expensive.

The first signal detection technique, an existing design utilizing discrete components is difficult to implement. They are very affordable to construct, but require precision tuning. This design is analyzed and found to be inaccurate.

The second signal …

Exploration Of Spatial Diversity In Multi-Antenna Wireless Communication Systems, Shichuan Ma

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

With increasing demand on wireless internet and personal multimedia, the data rate of wireless communications is expected to increase dramatically. Future wireless networks face challenges of supporting data rates higher than one gigabits per second. Among various technologies, multi-antennas, also known as multiple-input multiple-output (MIMO), are undoubtedly the most promising to enable higher data rates. By employing the extra degrees of freedom in the spatial domain, multi-antenna techniques enhance the wireless communication systems through array gain, spatial diversity, and spatial multiplexing. Although multi-antenna systems have been utilized for more than ten years, a thorough analysis of various aspects of multi-antenna …

Optimized Delay-Sensitive Multimedia Communications Over Wireless Networks, Haiyan Luo

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Multimedia communication is expected to be the major application of the next-generation wireless networks. However, providing delay-sensitive, loss-tolerant and resource-guzzling multimedia services over the current resource-limited wireless networks is still a very challenging task. In addition to their heterogeneous nature and resource limitation, wireless networks also suffer from channel variations and environmental changes. In this dissertation, we study the optimization techniques for wireless multimedia communications and address the issues from different theoretical and practical perspectives.

To solve the issues resulting from the increasingly heterogeneous wireless networks, we propose a framework for error resilient source coding and distributed application-layer error control, …

A Comprehensive Analysis Of Lte Physical Layer, Fahimeh Rezaei

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

The 3rd Generation Partnership Project (3GPP) introduced Long Term Evolution (LTE) as the 3rd generation of mobile communication standards. LTE Release 8 describes a mobile communication standard which supports up to 300 Mbps of data transmission in downlink using the OFDM scheme as well as up to 75 Mbps throughput for uplink using the SC-FDMA modulation. In this thesis, an in-depth study of LTE performance based on Release 8 is conducted for uplink and downlink under different scenarios. The main objective of this study is to investigate a comprehensive analysis of physical layer throughput of LTE Release8 based on standard …

Cross-Layer Optimized Wireless Multimedia Networking, Dalei Wu

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Multimedia communications, especially real-time video communications, is expected to be the major application of the next-generation wireless networks. However, bringing delay-sensitive and loss-tolerant multimedia services based on the current wireless Internet is a very challenging task. In this dissertation, we address cross-layer optimized wireless multimedia networking from both theoretical and practical perspectives. In the first part of the dissertation, we propose cross-layer optimization frameworks for real-time video communications over wireless networks, where the expected received video quality is adopted as the objective function. With the user-centric objective function, we first study content-aware video communications in single-hop wireless networks by exploring …

Study Of Physical Layer Security In Wireless Communications, Mustafa Duruturk

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

This thesis has investigated security in wireless communications at physical layer. Security is an important issue for wireless communications and poses many challenges. Most security schemes have been applied to the upper layers of communications networks. Since in a typical wireless communication, transmission of data is over the air, third party receiver(s) may have easy access to the transmitted data. This work discusses a new security technique at the physical layer for the MIMO (802.11n) transmitters. For this project, the wireless medium is secured by transmitting a noise signal that is only recoverable by the receiver. This report includes an …

Performance Of Self-Encoded Spread Spectrum Under Worst-Case Jamming, Casey L. Deyle

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

Performance of Self-Encoded Spread Spectrum Under Worst-Case Jamming Casey Deyle, M.S University of Nebraska 2009 Advisor: Lim Nguyen Spread Spectrum Communications uses m-sequences (sometimes referred to as Pseudo Noise or PN sequences) modulated with a data signal to create a transmission signal that takes up more bandwidth than the original information signal. Self-Encoded Spread Spectrum (SESS) uses spreading codes generated by the transmitted signal, eliminating the need to synchronize m-sequences between the transmitter and receiver, thus making the channel more secure. This paper will discuss the performance of SESS system in Additive White Gaussian Noise (AWGN) and Rayleigh fading channels, …

Quality-Driven Cross Layer Design For Multimedia Security Over Resource Constrained Wireless Sensor Networks, Wei Wang

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

The strong need for security guarantee, e.g., integrity and authenticity, as well as privacy and confidentiality in wireless multimedia services has driven the development of an emerging research area in low cost Wireless Multimedia Sensor Networks (WMSNs). Unfortunately, those conventional encryption and authentication techniques cannot be applied directly to WMSNs due to inborn challenges such as extremely limited energy, computing and bandwidth resources. This dissertation provides a quality-driven security design and resource allocation framework for WMSNs. The contribution of this dissertation bridges the inter-disciplinary research gap between high layer multimedia signal processing and low layer computer networking. It formulates the …

Robust Image And Video Coding With Adaptive Rate Control, Hongqiang Wang

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

This dissertation is focused on the problem of rate allocation in a resource constrained environment and robustness of video coding over noise channels. A new rate allocation scheme that combines the traditional PCRD-Opt algorithm with the rho domain analysis is proposed for wavelet based image coders. The proposed scheme provides competitive performance as compared with the optimal PCRD-Opt algorithm, while with great reduction on complexity and computational costs. Rate allocation is developed for the Region-Of-Interest (ROI) in the wavelet transform domain for image coding. A recursive region growing method that deter mines the ROI in the transform domain is proposed. …

Self-Encoded Spread Spectrum Synchronization And Cooperative Diversity, Kun Hua

Computer and Electronics Engineering: Dissertations, Theses, and Student Research

This dissertation research concerns a novel self-encoded spread spectrum. It provides a feasible practical implementation for random spreading codes. The traditional transmit and receive PN code generators are not needed. Instead, the spreading codes are extracted from the user's information bits itself. Comparing to conventional CDMA, SESS completely abandons the use of pseudo-random spreading codes. The code variability doesn't depend on the spreading length like pseudo-random codes.

But because the self-encoded spreading sequence is random and time varying, data recovery requires that the despreading sequence be identical with the spreading sequence at the start of the transmission. Synchronization is one …