Engineering Commons^™

Doppler Spread Estimation In Mobile Fading Channels, Hong Zhang

Dissertations

The Doppler spread, or equivalently, the mobile speed, is a measure of the spectral dispersion of a mobile fading channel. Accurate estimation of the mobile speed is important in wireless mobile applications which require such as knowledge of the rate of channel variations. In this dissertation, first the performance of classical crossing- and covariance-based speed estimators is studied. Next, the problem of mobile speed estimation using diversity combining is investigated. Then, a nonparametric estimation technique is proposed that is robust to different channel variations. Finally, cyclostationarity-based speed estimators which can be applied either blindly or with the aid of pilot …

Reactive Modification And Crystallization Behavior Of Foamed Poly(Butylene Terephthalate), Byeong Joon Jeong

Dissertations

The objective of this study is to investigate the feasibility of preparing low density foams based on poly(butylene terephthalate) (PBT) through modification of its molecular structure and rheological characteristics by reactive extrusion. The scientific and/or engineering interpretation of the experimental data was based on fundamentals of extrusion, crystallization mechanisms, as well as information on reactivity and tendency toward degradation of PBT.

As a preliminary study, the extrusion foaming behavior of a commercial linear semi-crystalline PBT with a chemical blowing agent (CBA) was investigated. Foam characteristics were functions of extrusion operational variables, such as die set temperature and screw speed. Gas …

Flow Characteristics And Phase Interactions Of Evaporating Sprays In Gas-Solid Suspensions, Muhammad Mushahid Rafique Qureshi

Dissertations

Evaporating spray jets have a wide range of applications in many industrial processes such as fluidized catalytic cracking of crude oil in petroleum refinery, coal gasification, fluidized coking to make synthetic crude oil, and condensed mode gas polymerization. The rapid evaporation of spray jets significantly affects the gas-solids mixing, solids concentration, gas/solids temperature and gas/solids velocity acceleration. The complex interactions mechanism of phase change, three phase interaction, heat and mass transfer of gas, solids and evaporating droplets dominate the process efficiency and product quality. In such three-phase flows, the phase transport characteristics are influenced by both droplet-gas interaction and droplet-solid …

Information Architecture For Irish Grocery Retailers Using Business Intelligence Tools, Patrick Doran

Dissertations

Business Intelligence (BI) systems have a pivotal role to play in assisting retail management in the Irish grocery retail sector. The emergence of super chain stores and the increasing competition within this sector only increases their need for an effective and reliable Business Intelligence (BI) system. However, despite this growing need Business Intelligence (BI) systems as they are currently deployed and used are not supplying the various levels of management with the necessary information they require to make effective retail management decisions. The information and reports received from Business Intelligence (BI) systems lack structure, are missing important pieces of information …

A Framework For The Introduction Of Organisational Learning Using Web 2.0 Applications, Joseph M. Reynolds

Dissertations

We are now becoming more and more dependent on web technologies in our personal lives for our communication, information and entertainment needs. But what about using these skills and technologies for our business lives, could they transform the business world in the same way they have transformed our personal world? The purpose of this research was to investigate whether the latest web applications could be successfully implemented into an organisation who wished to transform itself into a modern and flexible organisation. This research was primarily focused on introducing organisational learning into the business through the use of new technology and …

Using Gis To Assess Ireland's Knowledge Economy And Its Readiness For Knowledge Based Activity, Niall Mcguinness

Dissertations

The attractiveness of emerging low wages economics to primary industries such as manufacturing and production is forcing many western economies to transition to knowledge economies. In the absence of many forms of primary industry lost to low wage economies, the European Union and its members are fast realising the importance of attracting knowledge based enterprise in order to maintain Europe’s economic climate. Ireland too has a stated aim to become a knowledge economy by the year 2010. This can be achieved by investing in higher education and attracting knowledge industry to the country. Ireland has made some progress to achieving …

Open Software To Innovation: The Critical Success Factors Of Massively Multiplayer Online Role Playing Games (Mmorpg) In China And Ireland., Wei Chen

Dissertations

This project investigates the factors leading to the success of China’s Massively Multiplayer Online Role Playing Games (MMORPG) market and gives an analysis of how Open source has contributed to these success factors. It then will look at how the use of open source is mirrored in Ireland’s market for example, the software sector to see if the same factors are apparent or there are indicators of these. Knowledge Management plays a very important role for fasten the innovation of Open source software development in China.

Determining The Probability Of The Visual Detection Of Sink Marks On Differently Textured Injection Molded Products, Kurt Frederick Hayden

Dissertations

The injection molding segment of the plastics industry has historically exhibited an environment of intense competition. To remain competitive, manufacturers must ensure that molds will produce defect-free parts without multiple design revisions. Designers often use computer simulations to predict design problems before the construction of tooling. These sophisticated software applications will soon have the ability to simulate the final appearance of products. However, the effects of aesthetic defects such as sink marks and splay are often difficult to simulate accurately and effectively.

It is understood that surface textures can conceal minor aesthetic defects. A well-known example is the concealment of …

Sustainable Barrier Sbs Paperboard Coatings Using Co-Polymerized Shape Engineered Pigments, Lokendra Pal

Dissertations

This study concentrates on the development, application, characterization and optimization of shape engineered pigments and co-polymerized sustainable coatings to provide solid bleached sulfate (SBS) board with a barrier against water, water vapor, and gasses. In contrast to off-line extrusion coating with unsustainable petroleum based products, conventional and co-polymerized shape engineered pigmented dispersion coatings were used to improve barrier, surface, optical and mechanical properties of an SBS board.

It is very important for package and quick-service wares made from coated SBS board to maintain barrier and mechanical properties at high humidity and temperature applications. The coated SBS board package should protect …

Decision Support Systems In Product Development: A Batesian Network Approach For Injection-Molded Products, Jason S. Trahan

Dissertations

Attribute defects cause a majority of the scrap for many manufacturers injection-molding aesthetic parts, yet these defects receive little attention duringproduct development. Methods for preventing attribute defects have been hampered by the inability to quantify complex cause-effect relationships. However, the qualities of a burgeoning branch of knowledge-based systems, called Bayesian networks, have benefited various fields faced with similar circumstances.Bayesian networks have the capability of presenting causal relationships between variables in a graphical structure and quantitatively explaining their effects throughout that structure. These effects can be characterized by probabilities derived from sources, such as equations, historical data, rules-of-thumb or expert knowledge. …

On Mitigating Distributed Denial Of Service Attacks, Zhiqiang Gao

Dissertations

Denial of service (DoS) attacks and distributed denial of service (DDoS) attacks are probably the most ferocious threats in the Internet, resulting in tremendous economic and social implications/impacts on our daily lives that are increasingly depending on the wellbeing of the Internet. How to mitigate these attacks effectively and efficiently has become an active research area. The critical issues here include 1) IP spoofing, i.e., forged source lIP addresses are routinely employed to conceal the identities of the attack sources and deter the efforts of detection, defense, and tracing; 2) the distributed nature, that is, hundreds or thousands of compromised …

Unified Architecture Of Mobile Ad Hoc Network Security (Mans) System, Li Ling

Dissertations

In this dissertation, a unified architecture of Mobile Ad-hoc Network Security (MANS) system is proposed, under which IDS agent, authentication, recovery policy and other policies can be defined formally and explicitly, and are enforced by a uniform architecture. A new authentication model for high-value transactions in cluster-based MANET is also designed in MANS system. This model is motivated by previous works but try to use their beauties and avoid their shortcomings, by using threshold sharing of the certificate signing key within each cluster to distribute the certificate services, and using certificate chain and certificate repository to achieve better scalability, less …

Constitutive Modeling Of The Thermo-Mechanics Associated With Crystallizable Shape Memory Polymers, Gautam Barot

Dissertations

This research addresses issues central to material modeling and process simulations. Here, issues related for developing constitutive model for crystallizable shape memory polymers are addressed in details. Shape memory polymers are novel material that can be easily formed into complex shapes, retaining memory of their original shape even after undergoing large deformations. The temporary shape is stable and return to the original shape is triggered by a suitable mechanism such heating the polymer above a transition temperature. Crystallizable shape memory polymers are called crystallizable because the temporary shape is fixed by a crystalline phase, while return to the original shape …

Characterization Of Hypertension Through Multivariate Analysis Utilizing Linear And Nonlinear Methods, Diane L. Donnelly

Dissertations

Analysis of blood pressure by nonlinear methods is vastly underutilized in current research. As such, 24-hour ambulatory blood pressure data from a small cohort of borderline hypertensive and normotensive subjects were analyzed using linear and nonlinear methods. Data were collected and provided by researchers from Columbia University. The cohort size was twelve subjects, consisting of two groups of six each. Although disease state was known, group membership for individual subjects was not. Therefore, one aspect of this research was to separate the cohort, a-priori, into two distinct, evenly sized groups, based solely on analysis results. Separation was accomplished by the …

Automatic Modulation Classification Of Communication Signals, Zaihe Yu

Dissertations

The automatic modulation recognition (AMR) plays an important role in various civilian and military applications. Most of the existing AMR algorithms assume that the input signal is only of analog modulation or is only of digital modulation. In blind environments, however, it is impossible to know in advance if the received communication signal is analogue modulated or digitally modulated. Furthermore, it is noted that the applications of the currently existing AMR algorithms designed for handling both analog and digital communication signals are rather restricted in practice. Motivated by this, an AMR algorithm that is able to discriminate between analog communication …

Analytical Model For Staging Emergency Evacuations, Vivek V. Korikanthimath

Dissertations

Disaster response in areas of high population density is centered on the efficient evacuation of people and possibly goods. Developing evacuation plans suitable for different levels of urgency based on the intensity of threat is a challenging task. In case of densely populated cities (e.g., New York, Los Angeles), the level of threat is enhanced by the congestion of their transportation systems, and the decision to evacuate a region simultaneously or by dividing it into multiple stages (or zones) affects the required evacuation time and associated delays.

The evolution of the traffic conditions on the evacuation route can vary significantly …

Evaluation Of Environmental Carrying Capacity And Application Of The Sustainability Target Method, Chatpet Yossapol

Dissertations

The environmental carrying capacity (CC) is defined as the capacity of the earth to absorb or tolerate potentially stressful burdens imparted at various scales and locations, that is, to accommodate the ecological stresses without showing permanent damage. The CC can be used as a reference dataset for Life Cycle Assessment (LCA) purposes and as a baseline for other environmental studies.

In this research, a set of impact-oriented U.S. CC is developed for both input- and output-related impacts. CC for eight common impact categories is evaluated: resource depletion, global warming, ozone depletion, acidification, eutrophication, photochemical ozone formation, human toxicity, and eco-toxicity. …

The Impact Of Abiotic And Biogenic Mn Oxide Coatings On Contaminant Mobility, Bioavailability, And Attenuation, Thipnakarin Boonfueng

Dissertations

Abiotic and biogenic manganese oxide coatings significantly impact the mobility and bioavailability of metals in soils and sediments. While sorption to discrete Mn oxides has been investigated in a number of studies, coatings have not received as much attention. Abiotic nanocrystalline (hydrous manganese oxide (HMO)) and crystalline Mn oxides (bimessite and pyrolusite) coated on montmorillonite were studied for formation, structure, stability, and surface properties. Coatings dominated the clay surface characteristics where the surface charge behaved similar to that of the discrete oxide and the local structure was consistent with the pure oxide phase. Furthermore, in sorption studies, Zn and Pb …

The Effects Of Paper Physical Properties On Print Gloss And Ink Mileage, Renmei Xu

Dissertations

Ink film coat weight was measured using an internal tracer method. Commercial toluene based gravure inks were marked with the tracer, which can be detected analytically and used to calculate ink film coat weight. The ink film coat weight versus relative print density data was plotted and curve fitting was performed using six previous proposed models. The models that were used to fit laboratory results were also found useful for pilot plant press results. Oittinen model and Calabro-Savagnone model fitted the experimental data better than the other four models, measured by the sum of the square of residuals and their …

Ink Jet Inks And Substrates - Novel Approaches For Their Physical And Optical Properties Characterization, Veronika Lovell

Dissertations

Undoubtedly, within the last couple of decades, the progress in non impact printing technologies has grown to an enormous level. In order to keep the development of this non impact printing method to grow even more, technicians, researchers and educators must continue in conducting investigation and provoking new ideas and questions that will lead to new outcomes and expansion of ink jet printing.

In this work, a broader area that comprises deep look into the ink jet ink and substrate performance, their physical properties and optical properties when printed is discussed in great details. Innovative techniques, novel materials and novel …

Robust Kanban Design For A Lean Supply Chain, Hardik Shah

Dissertations

This research concentrates on the inventory management decisions within an assembly-type supply chain. The need for this type of investigation is warranted by the fact that intense competition and heightening demand from customers have forced businesses to focus their attention on strengthening their supply chains. The problem is that in any supply chain, there are many factors involved that cause variations and instability within the system. Previous literature indicates that the manipulation of a Kanban system in today's uncertain environment generates unfavorable results. Consequently, the goal is to find a Kanbanmethodology that would produce robust and consistent results even when …

Advanced Methods In Automatic Modulation Classification For Emerging Technologies, Hong Li

Dissertations

Modulation classification (MC) is of large importance in both military and commercial communication applications. It is a challenging problem, especially in non-cooperative wireless environments, where channel fading and no prior knowledge on the incoming signal are major factors that deteriorate the reception performance. Although the average likelihood ratio test method can provide an optimal solution to the MC problem with unknown parameters, it suffers from high computational complexity and in some cases mathematical intractability. Instead, in this research, an array-based quasi-hybrid likelihood ratio test (qHLRT) algorithm is proposed, which depicts two major advantages. First, it is simple yet accurate enough …

Dynamic Bandwidth Management With Service Differentiation Over Ethernet Passive Optical Networks, Yuanqiu Luo

Dissertations

Ethernet passive optical networks (EPONs) address the first mile of the communication infrastructure between the service provider central offices and the customer sites. As a low-cost, high speed technology, EPONs are deemed as the solution to the bottleneck problem of the broadband access network.

A major feature of EPONs is the utility of a shared upstream channel among the end users. Only a single optical network unit (GNU) may transmit during a timeslot to avoid data collisions. In order to provide diverse quality of service (QoS), the bandwidth management of the upstream channel is essential for the successful implementation of …

H-Simd Machine : Configurable Parallel Computing For Data-Intensive Applications, Xizhen Xu

Dissertations

This dissertation presents a hierarchical single-instruction multiple-data (H-SLMD) configurable computing architecture to facilitate the efficient execution of data-intensive applications on field-programmable gate arrays (FPGAs). H-SIMD targets data-intensive applications for FPGA-based system designs. The H-SIMD machine is associated with a hierarchical instruction set architecture (HISA) which is developed for each application. The main objectives of this work are to facilitate ease of program development and high performance through ease of scheduling operations and overlapping communications with computations.

The H-SIMD machine is composed of the host, FPGA and nano-processor layers. They execute host SIMD instructions (HSIs), FPGA SIMD instructions (FSIs) and nano-processor …

Effect Of Polymorphic Phase Transformations Within An Alumina Layer On The Ignition Of Aluminum Particles, Mikhaylo Aleksiyovych Trunov

Dissertations

Experimental measurements of aluminum ignition temperature and models used to describe aluminum ignition are reviewed. It is shown that the current models cannot describe ignition of aluminum powders of different sizes and ignited under various experimental conditions. The properties of and phase changes occurring in the alumina scale existing on the surface of aluminum particles at different temperatures are systematically studied. The mechanism of aluminum oxidation is quantified and a new simplified ignition model is developed.

Thermogravimetry was used to study the oxidation of aluminum powders of various particle sizes and surface morphologies in oxygen at temperatures up to 1500°C. …

Synthesis And Characterization Of Mechanically Alloyed Aluminum-Based Compounds As High Energy Density Materials, Xiaoying Zhu

Dissertations

A new type of metastable reactive powders for potential use as high energy density materials in propellants, explosives, and pyrotechnics was developed. These powders are intended to replace aluminum typically added to energetic formulations to increase reaction enthalpy and temperature. The new materials are metastable aluminum-based alloys, which enable achievement of substantially reduced ignition temperatures and accelerated bulk burn rates compared to aluminum. Titanium and lithium were used as alloying components. The materials properties and characteristics leading to their enhanced combustion performance were investigated. The powders were prepared using mechanical alloying and characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy …

Cross-Layer Design For Wireless Sensor Relay Networks, Lichuan Liu

Dissertations

In recent years, the idea of wireless sensor networks has gathered a great deal of attention. A distributed wireless sensor network may have hundreds of small sensor nodes. Each individual sensor contains both processing and communication elements and is designed in some degree to monitor the environmental events specified by the end user of the network. Information about the environment is gathered by sensors and delivered to a remote collector.

This research conducts an investigation with respect to the energy efficiency and the cross-layer design in wireless sensor networks. Motivated by the multipath utilization and transmit diversity capability of space-time …

Applications Of Room Temperature Ionic Liquids In Interfacial Polymerization, Lining Zhu

Dissertations

Room temperature ionic liquids (ILs), with their unique physical and chemical properties, have been of great interest in various areas of chemical science and engineering during the last decade. In this dissertation, polyurea and polyamide films with surface nanostructures were synthesized by interfacial polymerization (IP) with ILs without stirring. Both polymers were prepared at the interface between n-hexane and a series of 1 -alkyl-3-methylimidazolium ILs.

Nanoporous or nanofibrous polymer morphologies with various sizes ranging from 50 to 500 nm and geometries, depending on the ILs used, were observed by scanning electron microscopy (SEM). A correlation length of ~20nm and a …

Medium Access Control Design For All-Ip And Ad Hoc Wireless Network, Zaihan Jiang

Dissertations

Medium Access Control (MAC) protocol in a wireless network controls the access of wireless medium by mobile terminals, in order to achieve its fair and efficient sharing. It plays an important role in resource management and QoS support for applications. All-IP wireless WAN is fully IP protocol-based and it is a strong candidate beyond 3G (Third Generation Wireless Network). Ad hoc wireless network has recently been the topic of extensive research due to its ability to work properly without fixed infrastructure.

This dissertation is composed of two main parts. The first part pursues a Prioritized Parallel Transmission MAC (PPTM) design …

A Study On Perceptions Of Civil Engineers Regarding Mandatory Continuing Education, Alee A. Sleymann

Dissertations

This study explored the perceptions of civil engineers regarding continuing professional competency requirements for license renewal. In this study,continuing professional competency is assumed to have a direct relationship to public welfare and safety. The policy of mandatory continuing education was adopted primarily for this reason. Currently, mandatory continuing education is adopted by 29 states as the method of assuring continued professional competency.

Many professionals, however, have not welcomed this mandatory continuing education (MCE) policy. The reason for this opposition is the claimed ineffectiveness of this policy in fostering continued competency. In addition, the regulatory boards and policy advocates have not …