Engineering Commons^™

Numerical Modeling Of Wave Propagation In Nonlinear Photonic Crystal Fiber, Md. Kaisar Khan

Electronic Theses and Dissertations

In this dissertation, we propose numerical techniques to explain physical phenomenon of nonlinear photonic crystal fiber (PCF). We explain novel physical effects occurred in PCF subjected to very short duration pulses including soliton. To overcome the limitations in the analytical formulation for PCF, an accurate and efficient numerical analysis is required to explain both linear and nonlinear physical characteristics. A vector finite element based model was developed to precisely synthesize the guided modes in order to evaluate coupling coefficients, nonlinear coefficient and higher order dispersions of PCFs. This finite element model (FEM) is capable of evaluating coupling length of directional …

Stochastic Gaussian And Non-Gaussian Signal Modeling, Madhu Kishore Yerramothu

Open Access Theses & Dissertations

This thesis introduces a methodology for modeling stochastic signals that have either Gaussian or approximately bell-shaped non-Gaussian distribution. The synthesized model can be used to generate stochastic signals that approximate both the power spectral density (PSD) and the probability density function (pdf) of the original stochastic signal. The new methodology is based on non-linear transformations, filter banks and autoregressive-moving average (ARMA) models. Because the stochastic signals modeled can have Gaussian distribution or approximately bell shaped non-Gaussian distribution, normality tests such as sample skewness, sample kurtosis, Kolmogorov-Smirnov test, and Shapiro-Wilk test are also used.

Many methods have been proposed in the …

Design, Implementation And Evaluation Of A Networking Context Aware Policy Environment, Asanga Dhammika Udugama

Theses

Future mobile networks are anticipated to have support to access heterogeneous access technologies. An important question in such environments is the decisions on when to use what access network. These decisions must take the users and mobile network operators’ perspectives into consideration. The operators usually have a focus of always-best-managed networks while the users have an always-best-connected focus. A key enabler of such environments is the use of policies to perform these handover decisions. These policies, which must be dynamic in nature, should be configurable when the requirements change. Policy decisions are always made based on the current context of …

Elliptic Curve Cryptography Security On Restricted Mobile Devices, Debbie Mccann

Theses

Mobile technologies with limited resources, such as smart phones or PDAs, have increased dramatically in popularity. However, the level of security provided for these technologies has not kept pace with the value of the data that they contain or transmit.

Wireless networks usually provide some security, in the form of encryption. GSM and GPRS use different forms of the A5 algorithm, and Wi-Fi uses WEP or WPA. These encryption algorithms have proven weaknesses and in some cases have been efficiently cracked. To improve the security of wireless networks, stronger encryption algorithms need to be developed. One of the most attractive …

A Distributed Ai Approach For Large-Scale Wlan Design, Alan Mcgibney

Theses

The recent dramatic trend towards always-on-connectivity has driven the need for mobile ubiquitous computing environments with the advent of the Wireless Local Area Network (WLAN) seeing a shift from traditional wired networks to wireless networking. A WLAN typically contains a number of access points that allow wireless enabled clients access information and network resources such as the internet without the need for wires, offering flexibility and mobility to the users. Initial wireless networks were convenience based allowing users access to the primary wired network, and involved little planning prior to roll-out. The proliferation of low cost wireless devices combined wdth …

High Temperature Packaging For Wide Bandgap Semiconductor Devices, Brian Grummel

Electronic Theses and Dissertations

Currently, wide bandgap semiconductor devices feature increased efficiency, higher current handling capabilities, and higher reverse blocking voltages than silicon devices while recent fabrication advances have them drawing near to the marketplace. However these new semiconductors are in need of new packaging that will allow for their application in several important uses including hybrid electrical vehicles, new and existing energy sources, and increased efficiency in multiple new and existing technologies. Also, current power module designs for silicon devices are rife with problems that must be enhanced to improve reliability. This thesis introduces new packaging that is thermally resilient and has reduced …

Phonon-Energy-Coupling-Enhancement Effect And Its Applications, Pang-Leen Ong

University of Kentucky Doctoral Dissertations

Silicon Oxide/Oxynitride (SiO₂/SiON) has been the mainstream material used for gate dielectric for MOS transistors for the past 30 years. The aggressive scaling of the feature size of MOS transistor has limited the ability of SiO₂/SiON to work effectively as the gate dielectric to modulate the conduction of current of MOS transistors due to excess leakage current dominated by direct quantum tunneling. Due to this constraint, alternative gate dielectric/high-k is being employed to reduce the leakage current in order to maintain the rate of scaling of MOS transistors. However, the cost involved in the implementation of …

Teaching And Assessment Of Students Taking A First Year, Level 7 Subject: Analysis And Actions, Aidan O'Dwyer

Conference papers

This contribution critically analyses the teaching and assessment strategies used on the core Electrical Systems subject in the first year of a three-year, Level 7, degree programme in Electrical Engineering at Dublin Institute of Technology. The author has the responsibility for development and instruction in the subject since 2004. In the 2004-5 and 2005-6 academic years, the didactic teaching approach and the assessment strategy ensured good educational outcomes. This was not the case in the 2006-7 academic year. The contribution will analyse the reasons for this, taking an evidence-based approach (i.e. analysing the assessment data in detail). Two conclusions that …

Dual Bypass Gas Metal Arc Welding Process And Control, Xiaopei Liu

University of Kentucky Doctoral Dissertations

GMAW (Gas Metal Arc Welding) is one of the most important arc welding processes being adopted in modern manufacturing industry due to its advantages in productivity, energy efficiency and automation. By monitoring and improving some of the important properties of GMAW such as production rate, metal transfer and base metal heat input, researchers could bring the process efficiency and stability to a new level. In recent years, some innovative modifications of GMAW such as Twins, Tandem and laser-MIG hybrid welding have been adopted into many industrial applications for better productivity.

In this dissertation, a novel GMAW called DB-GMAW (Dual Bypass …

Evaluation Of An Image Processing Algorithm For Scene Change Detection, Daniel Flores

Open Access Theses & Dissertations

Despite the efforts to reduce traffic accidents by government entities and automobile manufactures, the numbers of accidents are not considerably reduced. An evaluation of an algorithm based on the fly's eye is done on this research applying its principles to detect scene change on images for printed circuit boards providing initial steps to implement this algorithm on vehicular traffic to keep track of objects moving on the field for collision avoidance purposes. The effectiveness of the algorithm is addressed through a comparison of its performance with that found in experimental data.

Zinc Telluride Deposition Using Close Space Sublimation, Luis Carlos Romo

Open Access Theses & Dissertations

This thesis presents the optimization process of the close space sublimation (CSS) technique to deposit zinc telluride (ZnTe) on thin-film cadmium telluride (CdTe) solar cells. Previous research has demonstrated that creating a heavily doped ZnTe intermediate layer between the absorber-CdTe and the back contacts produces low-resistive CdTe contacts that overcome the Schottky barrier created at the interface of a metal and a semiconductor [11]. ZnTe interlayer forms a tunnel barrier at the contact interface so the positive charges created at the p-CdTe/n-cadmium sulfide (CdS) junction can be easily collected at the back contact maximizing the current collection process. However, ZnTe …

A Novel Expanded 16-Dimensional Constant Envelope Q2psk Constellation, Milton I. Quinteros, Kenneth V. Cartwright, Edit J. Kaminsky, Ricardo U. Gallegos

Electrical Engineering Faculty Publications

We introduce a 16-dimensional constant-amplitude constellation that is generated by concatenating either four constant envelope quadrature-quadrature phase shift keying (CEQ2PSK) symbols from Saha and Birdsall or four CEQ2PSK symbols recently discovered by Cartwright and also introduced here. Our new constellation doubles the number of points available for data transmission without decreasing the distance between points or increasing energy, and may therefore be used in a trellis coded modulation (TCM) system without constellation expansion penalty. Because the new constellation has constant envelope, the modulation scheme becomes very attractive for nonlinear channels such as the magnetic recording channel or the satellite channel …

Classification Of Cylindrical Targets Buried In Seafloor Sediments, Edit J. Kaminsky, Madalina Barbu

Electrical Engineering Faculty Publications

This paper presents the development and evaluation of a time-frequency processing technique for detection and classification of buried cylindrical targets from chirpbased parametric sonar data. The software is designed to discriminate between cylindrical targets —such as cables— of different diameters, which need to be identified as different from other strong reflectors or point targets. The method is evaluated on synthetic data generated with an acoustic scattering model for elastic cylinders for seven different diameters. The model generates characteristic responses of targets acquired by a parametric sonar system. The signal at the sonar receiver hydrophones is first windowed to reduce the …

Antennas For Portable Communications In The Uwb And Gps Spectra., Giuseppe Ruvio

Doctoral

The thesis describes a study of antennas for solutions in emerging systems. An account of the fundamental principles of these antennas is given together with an outline of the basic electromagnetic theory on which the designs are based. While the main focus is on antennas for Ultra Wideband (UWB) systems, some additional work was carried out on enhancing performance of circularly polarised antennas for satellite navigation systems. The study focussed on the design of highly efficient broadband antennas with particular requirements for size compactness, gain stability, phase-linearity, and the use of low-cost materials. These requirements are particularly important for UWB …

A Mobile Ecg Monitoring System With Context Collection, Jin Peng Li

Masters

An objective of a health process is one where patients can stay healthy with the support of expert medical advice when they need it, at any location and any time. An associated aim would be the development of a system which places increased emphasis on preventative measures as a first point of contact with the patient. This research is a step along the road towards this type of preventative healthcare for cardiac patients. It seeks to develop a smart mobile ECG monitoring system that requests and records context information about what is happening around the subject when an arrhythmia event …

Guidelines For Deploying Wireless Sensor Network In Manufacturing: Star Topology Study Using The Rssi To Test The Network Performance, A. Hameed Madwar

Dissertations and Theses @ UNI

Wireless Sensor Networks (WSNs) are varying in kinds and can be used for many purposes. It can be extensively used in monitoring, reporting, and decision routines. Therefore, WSNs are very important to integrate with manufacturing since they can help not only in monitoring and decision making but also they can increase productivity and decrease the wiring costs. However, WSNs are facing some challenges in manufacturing as they need to resist the interferences that could be generated by the electrical and mechanical fields created during the manufacturing processes. Some of these interferences could be due to the high temperatures, blocks of …

Performance Comparison Of Pb(Zr0.52Ti0.48)O3-Only And Pb(Zr0.52Ti0.48)O3-On-Silicon Resonators, Hengky Chandrahalim, Sunil A. Bhave, Ronald G. Polcawich, Jeff Pulskamp, Dan Judy, Roger Kaul, Madan Dubey

Faculty Publications

This paper provides a quantitative comparison and explores the design space of lead zirconium titanate (PZT)–only and PZT-on-silicon length-extensional mode resonators for incorporation into radio frequency microelectromechanical system filters and oscillators. We experimentally measured the correlation of motional impedance (R_X) and quality factor (Q) with the resonators’ silicon layer thickness (t_Si). For identical lateral dimensions and PZT-layer thicknesses (t_PZT), the PZT-on-silicon resonator has higher resonant frequency (f_C), higher Q (5100 versus 140), lower R_X (51 Ω versus 205 Ω), and better linearity [third-order input intercept …

Drop Photometer Design., Kevin Tiernan

Doctoral

The tensiograph drop analyser, operating in the mode of ultraviolet-visual absorption photometer, was re-engineered to improve measurement accuracy. As well as instrumentation re-design, the other objective of the research was to analyse tensiograph signals to explore how their features are defined by drop properties. Using fibre optic technology, the tensiograph emits a light beam into a growing pendant drop whereupon it undergoes a number of internal reflections. A portion of the reflected light energy is coupled to a photodiode producing a proportional current that is electronically processed and transferred to a computer for analysis. The signal produced, known as the …

A Nondestructive Technique For Determining Complex Permittivity And Permeability Of Magnetic Sheet Materials Using Two Flanged Rectangular Waveguides, Milo W. Hyde Iv, Michael J. Havrilla

Faculty Publications

In this paper, a nondestructive technique for determining the complex permittivity and permeability of magnetic sheet materials using two flanged rectangular waveguides is presented. The technique extends existing single probe methods by its ability to simultaneously measure reflection and transmission coefficients imperative for extracting both permittivity and permeability over all frequencies. Using Love’s Equivalence Principle, a system of coupled magnetic field integral equations (MFIEs) is formed. Evaluation of one of the two resulting spectral domain integrals via complex plane integration is discussed. The system, solved via the Method of Moments (MoM),yields theoretical values for the reflection and transmission coefficients. These …

Trajectory Shaping Of Surface-To-Surface Missile With Terminal Impact Angle Constraint, S. Subchan

Makara Journal of Technology

This paper presents trajectory shaping of a surface-to-surface missile attacking a fixed with terminal impact angle constraint. The missile must hit the target from above, subject to the missile dynamics and path constraints. The problem is reinterpreted using optimal control theory resulting in the formulation of minimum integrated altitude. The formulation entails nonlinear, two-dimensional missile flight dynamics, boundary conditions and path constraints. The generic shape of optimal trajectory is: level flight, climbing, diving; this combination of the three flight phases is called the bunt manoeuvre. The numerical solution of optimal control problem is solved by a direct collocation method. The …

Limiting Maximum Drag Reduction Asymptote For The Moment Coefficient Of An Enclosed Rotating Disk With Fine Spiral Grooves, Budiarso Budiarso, Keizo Watanabe, Satoshi Ogata

Makara Journal of Technology

In this study, the limiting maximum drag reduction asymptote for the moment coefficient of an enclosed rotating disk with fine spiral grooves in turbulent flow region were obtained analytically. Analysis which were based on an assumption for a simple parabolic velocity distribution of turbulent pipe flow to represent relative tangential velocity, was carried out using momentum integral equations of the boundary layer. For a certain K- parameter the moment coefficient results agree well with experimental results for maximum drag reduction in an enclosed rotating disk with fine spiral grooves and drag reduction ratio approximately was 15 %. Additionally, the experimental …

Co2 Absorption From Its Mixture With Ch4 Or N2 Through Hollow Fiber Membrane Contactor Using Water As Solvent, Sutrasno Kartohardjono, Anggara Anggara, Subihi Subihi, Yuliusman Yuliusman

Makara Journal of Technology

CO2 Absorption from Its Mixture with CH4 or N2 through Hollow Fiber Membrane Contactor using Water as Solvent. Hollow fiber membrane contactors have been widely used as gas-liquid contactors recently such as in the CO2 absorption process from gas stream. This research aims to evaluate the effectiveness of hollow fiber membrane contactor to absorb CO2 from its mixture with CH4 or N2 using water through mass transfer and hydrodynamic tests. There are 3 membrane modules used in this research with shell diameter of 1.9 cm, length of 40 cm, outer fiber diameter of 2.7 mm and fiber number in the …

Reverse Link Cdma System Capacity Evaluation For Stratospheric Platform Mobile Communications, Iskandar Iskandar

Makara Journal of Technology

We propose an analysis of reverse link CDMA multispot beam stratospheric platforms (SPF) in this paper. The SPF is currently proposed as a novel wireless technology for the development of the next generation fixed and mobile communications. The geometry of this technology is different from that of the terrestrial but rather similar to the satellite based cellular system. However, evaluation on the CDMA system capacity of this technology has not been much reported. This paper addresses all possible multiple access interference analyses including the effects of channel fading and shadowing in order to evaluate the system capacity. Single SPF and …

The Potency Of Fire And Explosion Hazard On Premium Oil Storage Tank At Depot X 2007, Fatma Lestari, Warid Nurdiansyah

Makara Journal of Technology

The Potency of Fire and Explosion Hazard on Premium Oil Storage Tank at Depot X 2007. Premium oil storage tanks have fire and explosion risk because Premium oil is flammable liquid. Because of that, fire and explosion risk assessment on Premium oil storage tank at Depot X is needed as foundation to fire and explosion risk management, and comply with regulations. Method of this research is Dow’s Fire and Explosion Index. This research indicate that F&EI value for Premium oil storage tank is 118,82. Based on that F&EI value, level of risk at Premium oil storage tank is intermediate risk.

Analysis Of Three Phase Controlled Rectifier With The Same Distance Control As Compared To The Same Angle Control, Sudirman S., Sri Kurniati A.

Makara Journal of Technology

Analysis of three phase controlled rectifier with the same distance control as compared to the same angle control. This research aim to compare the firing of the same distance and the same angle control at three phase controlled rectifier with seen generated harmonic at input (AC side). Then calculate of rectifier efficiency and power factor comparison from both the control type. The rectifier use passive filter with resistance 11 ohm and is analysed with program simulation using PSPICE version 7.1. Result of research indicate that use of the same distance control generates the 5th and 7th harmonics, while the same …

The Use Of Red Cabbage’S Anthocyanine Extract As A Photosensitizer On A Dye-Sensitized Nanocrystalline Tio2 Solar Cell, Akhiruddin Maddu, Mahfuddin Zuhri, Irmansyah Irmansyah

Makara Journal of Technology

The use of Red Cabbage’s anthocyanine extract as a photosensitizer on a Dye-Sensitized Nanocrystalline TiO2 Solar Cell. A solid-state dye-sensitized nanocrystalline TiO2 solar cell utilizing anthocyanin extract form red cabbage as photosensitizer was fabricated. The solar cell was formed in sandwich structure, which two electrodes sandwiching polymer electrolyte containing a redox couple (I-/I3 -). One of the electrodes, namely working electrode, TiO2 layer on TCO (transparent conducting oxide) coated glass substrate was sensitized with anthocyanin dye as electron donor in the system. Another electrode was a carbon sheet as a counter electrode. Gel electrolyte based on PEG (polyethylene glycol) containing …

Effect Of Contact Time On Interface Reaction Between Aluminum Silicon (7% And 11%) Alloy And Steel Dies Skd 61, Bambang Suharno, Neni Octapiani Nurhayati, Bustanul Arifin, Sri Harjanto

Makara Journal of Technology

Effect of Contact Time on Interface Reaction between Aluminum Silicon (7% and 11%) Alloy and Steel Dies SKD 61. Die soldering (die sticking) is a defect of metal casting in which molten metal “welds” to the metallic die mold surface during casting process. Die soldering is the result of an interface reaction between the molten aluminum and the die material. Aluminum alloy with 7 and 11% silicon and SKD 61 die steel are the most common melt and die material used in aluminum die casting. This research is done to study the morphology and the characteristics of the formed AlxFeySiz …

Sub-Bottom Profiling Using Time-Frequency Analysis, William Sanders, Dale Bibee, Edit J. Kaminsky

Electrical Engineering Faculty Publications

No abstract provided.

The Capability Of The Edca Mechanism To Support Voice Traffic In A Mixed Voice/Data Transmission Over 802.11e Wlans: An Experimental Investigation, Miroslaw Narbutt, Mark Davis

Conference papers

In this paper we experimentally evaluate the capability of the EDCA mechanism to support voice traffic in a mixed voice/data transmission over 802.11e WLANs. In particular we investigate how real-time voice transmission can be supported by tuning four EDCA parameters, namely AIFSN, CWmin, CWmax and TXOP and how this impacts on background data transmission. The experimental set-up involves fifteen VoIP terminals sending bi-directional traffic between wired and wireless subnets and another station injecting various types of heavy background load to the wireless subnet. End-to-end voice transmission quality is predicted from time-varying transmission impairments with the use of the latest Appendix …

Embedded Centrosymmetric Multilayer Stacks As Complete-Transmission Quarter-Wave And Half-Wave Retarders Under Conditions Of Frustrated Total Internal Reflection, S. R. Perla, R. M.A. Azzam

Electrical Engineering Faculty Publications

A centrosymmetric multilayer stack of two transparent materials, which is embedded in a high-index prism, can function as a complete-transmission quarter-wave or half-wave retarder (QWR or HWR) under conditions of frustrated total internal reflection. The multilayer consists of a high-index center layer sandwiched between two identical low-index films with high-index–low-index bilayers repeated on both sides of the central trilayer, maintaining the symmetry of the entire stack and constituting a QWR ( Δt=90° or 270°) or HWR (Δt=180°) in transmission. A QWR design at wavelengthλ=1.55 μm is presented that employs an 11-layer stack of Si and SiO2 thin films, which is …