Digital Commons Network^™

Energy Efficient Organization And Modeling Of Wireless Sensor Networks, Jin Zhu

Dissertations

With their focus on applications requiring tight coupling with the physical world, as opposed to the personal communication focus of conventional wireless networks, wireless sensor networks pose significantly different design, implementation and deployment challenges. Wireless sensor networks can be used for environmental parameter monitoring, boundary surveillance, target detection and classification, and the facilitation of the decision making process. Multiple sensors provide better monitoring capabilities about parameters that present both spatial and temporal variances, and can deliver valuable inferences about the physical world to the end user.

In this dissertation, the problem of the energy efficient organization and modeling of dynamic …

Enhancing End-To-End Quality Of Service Provisioning In Wireless Ad Hoc Networks Using Service Vectors, Didem Gozupek

Theses

A cross-layer architecture that achieves significant power savings, while enhancing the end-to-end QoS provisioning and granularity in wireless ad hoc networks is proposed in this thesis. Recently, a new concept called service vector has been introduced, which enables an end host to choose different service classes along its data path. This scheme enhances the user benefits from the network services and network resource utilization, while maintaining the simplicity and scalability of the current Differentiated Services (DiffServ) network architecture. This thesis explores the application of this concept on wireless ad hoc networks and provides a cross-layer architecture based on the combination …

Automated Liquid Dispensing Pin For Dna Microarray Applications, Suganya Parthasarathy

Theses

This thesis describes the research and development of a new liquid dispensing/aspiring system that is capable of producing micro sized spots/droplets for molecular biology research and analysis. In particular, the application is focused on DNA microarray fabrication with the goals of smaller spot size, higher yield, more efficient usage of biological materials, and capability to handle high viscosity liquids. The new system is based on active sensing and control and it is part of a fully integrated robotic microarray system for genomic and proteomic applications. The prototype system handles water as well as thick liquids such as 100% glycerol and …

Multicodes For Improved Range Resolution In Radar, Rhiya Vitto

Theses

Third generation (3G) wireless systems are required to support a variety of communication services like voice, image, motion picture transmission, etc, each of which requires different transmission rates. Multi-code modulation has been introduced therefore as a means of supporting multi-rate services and operating in multi-cell environments [8, 9, 10]. This multi-rate multi-function capability may be used in Radar related applications, too. For example, a single transmitted waveform consisting of two orthogonal codes can be used to simultaneously track a target and obtain high range resolution. Tracking requires low bandwidth and high resolution needs a high bandwidth signal. Orthogonal codes like …

Deposition Of Tantalum Thin Films By Rf Sputtering With Substrate Bias, Savita Raina

Theses

The effects of energetic ion bombardment on the crystallographic structure of RF sputtered tantalum thin films on different substrates, particularly aluminum and silicon, have been studied. The effect of substrate biasing on ion current and film thickness has been investigated. The study included comparison between substrate ion current of DC sputtering and RF sputtering and also was aimed at finding the process parameters, which could influence the crystallographic phase of Ta film. The characterization of Ta films is carried by RBS and x-ray diffraction techniques.

A magnetron sputtering system with a matching network between the source and the RF generator …

Research Progresses In A Flow Redox Battery, Quan-Feng Dong, Hua-Min Zhang, Ming-Gang Jin, Ming-Sen Zheng, Ya-Ding Zhan, Shi-Gang Sun, Zu-Geng Lin

Journal of Electrochemistry

As a large scale electrochemical storage device, flow redox battery in which the active materials are flowing electrolytes is different from the common batteries employing solid or gas materials as an electrode. In this paper we introduced flow redox battery in brief, reviewed its development and actual state on (study). The main problem existed in the new device was discussed when viewed with its future developments.

The Research Of Nano-Sized Nio Anode Materials For Lithium Ion Batteries, Jun-Mei Yan, Jing Zhang, Yong Yang

Journal of Electrochemistry

The nano-sized NiO materials were synthesized by solid phase method and sol-gel method. The synthesis conditions were optimized by DSC and TG techniques. The sol-gel method was optimized by changing the solvent and regulating the solution's pH for preparing NiO material. The structure and morphology of the materials were also characterized by means of XRD and TEM techniques, and the electrochemical performances of the materials were studied by the galvanostatically charge and discharge experiments.

Keynote: Research And Education In Telecommunication Engineering, Akhtar Kalam

International Conference on Information and Communication Technologies

Telecommunications over the past one hundred years has had a major influence on the development of society. Telecommunications will continue to play an increasingly important role in nearly every human endeavour in all nations of the earth. Telecommunication industry is currently facing a technological revolution. In many countries, the number of cellular radio subscribers exceeds the subscribers of fixed telephony services. Internet technologies, such as VoIP and SIP, allow the convergence of traditional switched telephony services and data services of the internet to converge. New wireless access technologies compete and complete the services provided by the modern cellular radio networks. …

A Chain-Type Wireless Sensor Network For Monitoring Long Range Infrastructures, Chang Wen Chen, Yu Wang, Ivica Kostanic

Electrical Engineering and Computer Science Faculty Publications

We present in this paper an investigation on a special class of wireless sensor networks for monitoring critical infrastructures that may extend for hundreds of miles in distances. Such networks are fundamentally different from traditional sensor networks in that the sensor nodes in this class of networks are deployed along narrowly elongated geographical areas and form a chain-type topology. Based on careful analysis of existing sensor network architectures, we first demonstrate the needs to develop new architecture and networking protocols to match the unique topology of chain-type sensor networks. We then propose hierarchical network architecture that consists of clusters of …

Optical Amplifiers For 10 Gb/S Wdm Recirculating Loop Testbed, Sravanthi Thotakura

Electrical Engineering Theses - Archive

This Master's thesis deals with building experimental setup for characterization of novel nonlinear optical devices for fiber communication. The first part of the thesis deals with the description of the theoretical basis for operation of a particular type of such nonlinear optical devices, namely a parametric amplifier. Document includes deriving and solving the equations for parametric amplification in optical fiber when signal, idler and pump beams are linearly co-polarized. We consider both non-degenerate and degenerate pump cases for arbitrary phase mismatch. In the second part of the thesis we present the design and experimental implementation of electrical interface between commercial …

Effects Of Mutual Coupling On Interference Mitigation With A Focal Plane Array, Michael A. Jensen, Karl F. Warnick

Faculty Publications

A focal plane array feed of electrically small elements has been proposed as a means for achieving high sensitivity for radio astronomy applications in the presence of radio frequency interference (RFI). For a broadband system, mutual coupling effects become significant as the array element spacing becomes small relative to the electromagnetic wavelength. We present a theoretical framework for modeling the effects of mutual coupling and for determining the optimal multiport matching network between array elements and front-end transistor low-noise amplifiers for maximum signal-to-noise ratio (SNR). Numerical results are given for a model scenario including spillover and amplifier thermal noise and …

Distance Estimation Algorithm For Stereo Pair Images, Edwin Tjandranegara

Department of Electrical and Computer Engineering Technical Reports

Various algorithms have been proposed for estimating camera distance from objects in digital stereo pair videos and images. Existing algorithms assume that digital images were taken with pan and tilt cameras or assume that the angles between the cameras and the object are known. The algorithm that we are proposing has the ability to calculate distance from the camera plane to the object plane, where the cameras do not have the ability to pan and tilt nor the angles between the cameras and the object are known beforehand.

Knowledge Representation, Organization, And Formalization For Simulation Modeling Of Discrete Manufacturing System, Jung Hung Ma

All-Inclusive List of Electronic Theses and Dissertations

Simulation is an useful tool that helps managers making decision by designing models for real systems. It helps companies to study behaviors of real systems hy analyzing computer models and improve the systems based on the experiments' results. However, cross-domain knowledge requirement and lack of tools facilitate modeling are the main reasons that make industries hesitate to use simulation to assist making decision. This research is an attempt to develop robust knowledge representations for discrete manufacturing system and conceptual simulation model. A modeling methodology was proposed to utilize these knowledge representations (KRs) for developing conceptual simulation models from application domain …

The Impact Of Antenna And Rf System Characteristics On Mimo System Capacity, Matthew Leon Morris

Theses and Dissertations

The recent growth in demand for wireless services coupled with the limited spectrum available for these services has spawned new efforts to increase the spectral efficiency of wireless links. Recent research has shown that in multipath propagation environments, the spatial characteristics of the propagation channel can be exploited to increase spectral efficiency through the use of multiple antennas at the transmitting and receiving nodes. Such multiple-input multiple-output (MIMO) systems show promise for dramatic performance gains over their single-antenna counterparts. However, MIMO system performance is influenced by many different factors. Antenna array configuration directly contributes to MIMO system performance. The ability …

Reduced Complexity Detection Methods For Continuous Phase Modulation, Erik Samuel Perrins

Theses and Dissertations

Continuous phase modulation (CPM) is often plagued by high receiver complexity. One successful method of dealing with this is the well-known pulse amplitude modulation (PAM) representation of CPM, which was first proposed by Laurent. It is shown that the PAM representation also applies to multi-h CPM and ternary CPM, two previously unconsidered cases. In both cases it is shown that many PAM components may be required to exactly represent the signal. This is especially true of partial-response systems where the memory of the signal is long. Therefore, approximations are proposed which require only a limited number of terms. These extensions …

An Energy-Efficient Media Access Control Protocol For Chain-Type Wireless Sensor Networks, Yu Wang, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

We present in this paper an energy efficient media access control (MAC) protocol for chain-type wireless sensor networks. The chain-type sensor networks are fundamentally different from traditional sensor networks in that the sensor nodes in this class of networks are deployed along narrow and elongated geographical areas and form a chain-type topology. Recently, we have successfully developed hierarchical network architecture, sensor deployment strategy, and corresponding network initialization and operation protocols for this class of sensor networks. In this paper, we present a novel TDMA scheduling protocol that takes full advantages of the available channel reuse inherent in the chain-type sensor …

Application-Specific Routing Scheme For Indoor Wireless Localization Systems, Tamas Kasza, Chang Wen Chen

Electrical Engineering and Computer Science Faculty Publications

The proposed research focuses on the communication in an RF-based indoor wireless localization system. In such a system, wireless badges attached to people or devices report positions to wireless gateway units. Badges have very limited communication, energy, as well as processing capabilities. However, gateways are significantly less constrained by battery than the badges. Wireless gateway units route collected badge information hop-by-hop towards one central unit of the system. We assume that each gateway unit has one transceiver antenna and is able to determine its own relative position in the system. The goal of this research is to develop an application-specific …

A Flexible Infrastructure For Multi-Agent Systems, Gerrit Addison N Sorensen

Theses and Dissertations

Multi-Agent coordination and control has been studied for a long time, but has recently gained more interest because of technology improvements allowing smaller, more versatile robots and other types of agents. To facilitate multi-agent experiments between heterogeneous agents, including robots and UAVs, we have created a test-bed with both simulation and hardware capabilities. This thesis discusses the creation of this unique, versatile test-bed for multi-agent experiments, also a unique graph creation algorithm, and some experimental results obtained using the test-bed.

Developing A Shared Vision: Strategic Planning As A Guide To Technology Funding

ACUTA: Other Publications

In December 2004 ACUTA and WTC sent a survey to 768 ACUTA primary members to determine what issues were important on campuses today and what issues respondents felt will be of importance in the next few years. Questions related to management, strategy, infrastructure, technology, organization, polity, and funding. One of the most interesting observations is that the current and five-year rankings are nearly identical- today's concerns are also your concerns for the future. Here are the highlights of our findings:

A cluster of five management issues were rated very close to the same importance. This cluster included developing a vision …

Performance Evaluation Of Resource Usage For Unicast Video Streaming Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis

Conference papers

Multimedia streaming applications are a demanding and challenging service to deliver over wireless networks. Such services have a large impact on the resource requirements of the WLAN. However, there are many variables involved in video streaming, such as the video content being streamed, how the video is encoded and how it is sent. This makes the role of radio resource management and the provision of QoS guarantees extremely difficult. In this paper we investigate the network resource requirements for three scenarios: a single unicast video streaming session; multiple unicast video streaming sessions and finally multiple unicast streaming sessions in the …

Improved Network Analysis Of Coupled Antenna Diversity Performance, Michael A. Jensen, Matthew L. Morris

Faculty Publications

This paper presents a new framework for the analysis of mutually coupled diversity antennas based on network theory. The network model incorporates the matching network between the antennas and front-end amplifiers and uses a realistic model for the amplifier noise. The resulting analysis includes the impact of the coupled-antenna radiation patterns and impedance characteristics in determining the branch signal-to-noise ratios (SNRs). Application of the formulation to coupled dipole antennas characterized using full-wave electromagnetic analysis illustrates that a matching network providing a minimum amplifier noise figure achieves significantly better diversity performance than one providing maximum power transfer.

The Case For Thoroughly Testing Complex System Dynamic Models, Wayne Wakeland, Megan Hoarfrost

Complex Systems Faculty Publications and Presentations

In order to determine whether model testing is as useful as suggested by modeling experts, the full battery of model tests recommended by Forrester, Senge, Sterman, and others was applied retrospectively to a complex previously-published system dynamics model. The time required to carry out each type of test was captured, and the benefits that resulted from applying each test was determined subjectively. The resulting benefit to cost ratios are reported. These ratios suggest that rather than focusing primarily on sensitivity testing, modelers should consider other types of model tests such as extreme condition tests and family member tests. The study …

Power Transmission Control Using Distributed Max-Flow, Bruce M. Mcmillin, Austin Armbruster, Mariesa Crow, Michael R. Gosnell

Computer Science Faculty Research & Creative Works

Existing maximum flow algorithms use one processor for all calculations or one processor per vertex in a graph to calculate the maximum possible flow through a graph's vertices. This is not suitable for practical implementation. We extend the max-flow work of Goldberg and Tarjan to a distributed algorithm to calculate maximum flow where the number of processors is less than the number of vertices in a graph. Our algorithm is applied to maximizing electrical flow within a power network where the power grid is modeled as a graph. Error detection measures are included to detect problems in a simulated power …

Mobility-Pattern Based Localization Update Algorithm For Mobile Wireless Sensor Networks, Mohammad Yacoub Al-Laho

Electrical & Computer Engineering Theses & Dissertations

In mobile wireless sensor networks, sensors move in the monitored area at any direction and speed. Unlike many other networking hosts, sensor nodes do not have global addresses. They are often identified by using a location-based addressing scheme. Therefore, it is important to have the knowledge of the sensor location indicating where the data came from. In this thesis, three localization update algorithms were designed, Specifically, a sensor movement is divided into three states: Pause, Linear, and Random. Each state adopts different localization update algorithm. Since complex movement involves different mobility patterns, a state transition model is developed to …

Implementation Of Problem-Based Learning In Senior Engineering Design-I (Ece 485w), Fawaz Muzaffer Hussain

Electrical & Computer Engineering Theses & Dissertations

Problem-Based Learning is an approach where knowledge is acquired in the context of the problem. Students are provided with the problem specifications and resources that might prove to be helpful in solving the problem. They attack these real world problems in groups, analogous to the practice in the professional engineering world. This mode of teaching was adopted to deliver the Senior Engineering Design — I course (ECE 485W), offered to freshman engineering undergraduate students in the Electrical and Computer Engineering Department at Old Dominion University, Norfolk. This thesis documents the various pedagogical methods implemented into the course, which were introduced …

Monte Carlo Simulation Analysis Of Electron Bombardment Of Gallium Nitride For Particle Detector Applications, James Gibson Bolitho

Electrical & Computer Engineering Theses & Dissertations

Gallium Nitride (GaN) is a relatively new and promising semiconductor material. It is finding its place in commercial applications such as transistors, light-emitting diodes, and in blue lasers. The large bandgap of GaN allows for very low canier densities and high breakdown voltages. This combination results in a greatly reduced background current and noise, and can withstand large applied voltages. In addition, GaN is sturdy and has strong mechanical properties. These are all ideal characteristics for application in high-energy particle detection.

In this thesis, the central goal is to assess the response of a GaN-based particle detector through numerical modeling. …

Electromagnetic Wave Propagation Prediction For Wireless Networks Inside Boeing Fuselages, Mennatoallah Youssef

Electrical & Computer Engineering Theses & Dissertations

Commercial grade software is intended for electromagnetic predictions within office buildings; it was used to develop models to analyze propagation inside airplane fuselages. This study shows that Wireless XGTD and Insite software can accurately predict power propagation within airplane fuselages. Current work uses fuselage models, which contain additional internal components. A comparison was made between empty and full fuselage to examine the effects of internal components. Two propagation model types [Fast 3D and Full 3D] were also compared for accuracy to experimental study. It was concluded that completed fuselages are suggested for further simulation study as well as that the …

An Assessment Of The Audio Codec Performance In Voice Over Wlan (Vowlan) Systems, Miroslaw Narbutt, Mark Davis

Conference papers

In this paper we present results of experimental investigation into the performance of three audio codecs (ITU-T G.711, G.723.1 and G.729A) under varying load conditions on a Voice over WLAN system utilizing the IEEE 802.11b wireless LAN standard. The analysis is based upon a new technique for estimating user satisfaction of speech quality calculated from packet delay and packet loss/late measurements. We also demonstrate the importance of the de-jitter buffer playout scheme for insuring speech quality. From our results we conclude that the use of the G.711 audio codec in conjunction with the new adaptive playout scheme gives the highest …

Electromagnetic Propagation Prediction Inside Aircraft Cabins, Genevieve Hankins

Electrical & Computer Engineering Theses & Dissertations

Electromagnetic propagation models for signal strength prediction within aircraft cabins are essential for evaluating and designing a wireless communication system to be implemented onboard aircraft. There are many commercially available software packages for predicting wireless system performance in conventional indoor environments. It is of interest to examine the available software to determine if the aircraft's electromagnetic environment (EME) can be modeled successfully without developing an aircraft specific prediction tool. EnterprisePlanner®, a registered product of Wireless Valley Communications, Incorporated, was selected for the present effort. The performance of the prediction model was evaluated through a comparison with field measurements taken on …

A Multiplier-Less Architecture For High Speed Computation Of Multi-Dimensional Convolution, Ming Zhu Zhang

Electrical & Computer Engineering Theses & Dissertations

One of the most computationally intensive operations in digital image/video processing systems is multi-dimensional convolution. Every image/video processor needs the convolution module in its pre-processing stage. Fast and efficient design of the convolution module in an application specific system is a great challenge in VLSI (Very Large Scale Integration) design. Convolution operator requires a large set of multipliers and accumulators. A high precision multiplier takes enormous amount of VLSI area and it consumes more power. Hence reduction of the number of multipliers is another important challenge in VLSI design. A multiplier-less architecture for the design of a multi-dimensional convolution module …