Multi-Physics Modeling Of Induction-Based Additive Manufacturing Of Metals,
2012
University of Texas at El Paso
Multi-Physics Modeling Of Induction-Based Additive Manufacturing Of Metals, Danny W. Muse
Open Access Theses & Dissertations
The shift towards 3D printing of functional products has provided a glimpse of the future in terms of manufacturing technologies and the creation of volumetrically complex structures made possible only through these technologies. 3D printing has emerged from the culmination of several technologies covering multiple industries and a myriad of materials. Unlike subtractive technologies such as mills, lathes and CNC machines, where material is removed from a bulk slab or billet to produce a desired part, 3D printing uses an additive layered approach to deposit material based on cross sections of the desired part. Both approaches produce parts based on …
Modeling Power Consumption Of High Performance Computer Clusters,
2012
University of Texas at El Paso
Modeling Power Consumption Of High Performance Computer Clusters, Mario Caire
Open Access Theses & Dissertations
This dissertation describes a utilization-based power modeling approach that makes use of the /proc file system and is applied to estimating power load and energy consumption of high performance computer clusters. A full cluster power model is specified that meets the following conditions: 1) provides accurate energy estimates; 2) consists of a minimal number of variables; and 3) the selected variables provide a sufficient degree of explanation of the primary OS level contributors to power consumption. The cluster power model is based on analysis at the system or compute-node level, where various models are developed and evaluated. All models described …
On The Development Of A Digital Forensics Curriculum,
2012
Purdue University, Calumet
On The Development Of A Digital Forensics Curriculum, Manghui Tu, Dianxiang Xu, Samsuddin Wira, Cristian Balan, Kyle Cronin
Journal of Digital Forensics, Security and Law
Computer Crime and computer related incidents continue their prevalence and frequency, resulting in losses approaching billions of dollars. To fight against these crimes and frauds, it is urgent to develop digital forensics education programs to train a suitable workforce that can effectively investigate computer crimes and incidents. There is presently no standard to guide the design of digital forensics curriculum for an academic program. In this research, previous work on digital forensics curriculum design and existing education programs are thoroughly investigated. Both digital forensics educators and practitioners were surveyed and results were analyzed to determine the industry and law enforcement …
Modeling And Control Of Discrete Event Systems Using Finite State Machines With Variables And Their Applications In Power Grids,
2012
University of New Haven
Modeling And Control Of Discrete Event Systems Using Finite State Machines With Variables And Their Applications In Power Grids, Junhui Zhao, Le Yi Wang, Zhong Chen, Feng Lin, Hongwei Zhang
Electrical & Computer Engineering and Computer Science Faculty Publications
Control theories for discrete event systems modeled as finite state machines have been well developed to address various fundamental control issues. However, finite state machine model has long suffered from the problem of state explosion that renders it unsuitable for some practical applications. In an attempt to mitigate the state explosion problem, we propose an efficient representation that appends finite sets of variables to finite state machines in modeling discrete event systems. We also present the control synthesis techniques for such finite state machines with variables (FSMwV). We first present our notion and means of control under this representation. We …
Characterizing Metal-Insulator-Transition (Mit) Phase Change Materials (Pcm) For Rf And Dc Micro-Switching Elements,
2012
Air Force Institute of Technology
Characterizing Metal-Insulator-Transition (Mit) Phase Change Materials (Pcm) For Rf And Dc Micro-Switching Elements, Brent L. Danner, Ronald A. Coutu Jr.
Electrical and Computer Engineering Faculty Research and Publications
Metal-insulator transition (MIT) phase-change materials (PCM) are material compounds that have the ability to be either conductors or insulators depending on external stimuli. A micromachined test structure for applying external electric fields across MIT wire segments was designed and fabricated. Using this novel test structure, Germanium Telluride (GeTe) and Vanadium Oxide (VOx) were successfully transitioned from a conductor to an insulator. The resistivity of the GeTe wire segments increased three to five orders of magnitude with ∼40 V applied to the parallel plates of the test structure. The VOx wires exhibited an order of magnitude transition in resistivity with ∼20 …
A Mems Photoacoustic Detector Of Terahertz Radiation For Chemical Sensing,
2012
Air Force Institute of Technology
A Mems Photoacoustic Detector Of Terahertz Radiation For Chemical Sensing, Nathan Glauvitz, S. Blazevic, Ronald A. Coutu Jr., Michael Kistler, Ivan R. Medvedev, Douglas T. Petkie
Electrical and Computer Engineering Faculty Research and Publications
A piezoelectric Microelectromechanical system (MEMS) cantilever pressure sensor was designed, modeled, fabricated, and tested for sensing the photoacoustic response of gases to terahertz (THz) radiation. The sensing layers were comprised of three thin films; a lead zirconate titanate (PZT) piezoelectric layer sandwiched between two metal contact layers. The sensor materials were deposited on the silicon device layer of a silicon-on-insulator (SOI) wafer, which formed the physical structure of the cantilever. To release the cantilever, a hole was etched through the backside of the wafer and the buried oxide was removed with hydrofluoric acid. Devices were then tested in a custom …
Multiplication Theory For Dynamically Biased Avalanche Photodiodes: New Limits For Gain Bandwidth Product,
2012
Marquette University
Multiplication Theory For Dynamically Biased Avalanche Photodiodes: New Limits For Gain Bandwidth Product, Majeed M. Hayat, David A. Ramirez
Electrical and Computer Engineering Faculty Research and Publications
Novel theory is developed for the avalanche multiplication process in avalanche photodiodes (APDs) under time-varying reverse-biasing conditions. Integral equations are derived characterizing the statistics of the multiplication factor and the impulse-response function of APDs, as well as their breakdown probability, all under the assumption that the electric field driving the avalanche process is time varying and spatially nonuniform. Numerical calculations generated by the model predict that by using a bit-synchronous sinusoidal biasing scheme to operate the APD in an optical receiver, the pulse-integrated gain-bandwidth product can be improved by a factor of 5 compared to the same APD operating under …
A Suspended Nanogap Formed By Field-Induced Atomically Sharp Tips,
2012
Marquette University
A Suspended Nanogap Formed By Field-Induced Atomically Sharp Tips, Jun Hyun Han, Kyung Song, Shankar Radhakrishnan, Sang Ho Oh, Chung Hoon Lee
Electrical and Computer Engineering Faculty Research and Publications
A sub-nanometer scale suspended gap (nanogap) defined by electric field-induced atomically sharp metallic tips is presented. A strong local electric field (>109 V=m) across micro/nanomachined tips facing each other causes the metal ion migration in the form of dendrite-like growth at the cathode. The nanogap is fully isolated from the substrate eliminating growth mechanisms that involve substrate interactions. The proposed mechanism of ion transportation is verified using real-time imaging of the metal ion transportation using an in situ biasing in transmission electron microscope (TEM). The configuration of the micro/nanomachined suspended tips allows nanostructure growth of a wide variety of …
Effects Of Visual Interaction Methods On Simulated Unmanned Aircraft Operator Situational Awareness,
2012
Rockwell Collins Simulation & Training Solutions, Orlando, FL
Effects Of Visual Interaction Methods On Simulated Unmanned Aircraft Operator Situational Awareness, Brent A. Terwilliger
Publications
The limited field of view of static egocentric visual displays employed in unmanned aircraft controls introduces the soda straw effect on operators, which significantly affects their ability to capture and maintain situational awareness by not depicting peripheral visual data. The problem with insufficient operator situational awareness is the resulting increased potential for error and oversight during operation of unmanned aircraft, leading to accidents and mishaps costing United States taxpayers between $4 million to $54 million per year. The purpose of this quantitative experimental completely randomized design study was to examine and compare use of dynamic eyepoint to static visual interaction …
A Design Tool For Wsn Design In Buildings,
2012
Department of Electronic Engineering, Cork Institute of Technology, Cork, Ireland.
A Design Tool For Wsn Design In Buildings, Antony Guinard
Theses
The combination of sensing, processing, communication and actuation has made the monitoring and operation of buildings a significant emerging application area for Wireless Sensor Networks (WSN). The design, implementation and management of WSN is a complex task requiring a broad spectrum of disciplines such as networking and protocols, information management and embedding engineering to be successful. Indoor environments in particular pose a number of challenges that make the design of wireless networks a difficult task. These include the influence of obstacles and people on radio propagation, ever evolving building layout and interference from other wireless networks. The large-scale adoption of …
Strategies For The Intelligent Selection Of Components,
2012
Edith Cowan University
Strategies For The Intelligent Selection Of Components, Valerie Maxville
Theses: Doctorates and Masters
It is becoming common to build applications as component-intensive systems - a mixture of fresh code and existing components. For application developers the selection of components to incorporate is key to overall system quality - so they want the `best'. For each selection task, the application developer will de ne requirements for the ideal component and use them to select the most suitable one. While many software selection processes exist there is a lack of repeatable, usable, exible, automated processes with tool support. This investigation has focussed on nding and implementing strategies to enhance the selection of software components. The …
Continuous Time-Varying Biasing Approach For Spectrally Tunable Infrared Detectors,
2012
University of New Mexico
Continuous Time-Varying Biasing Approach For Spectrally Tunable Infrared Detectors, Woo-Yong Jang, Majeed M. Hayat, Payman Zarkesh-Ha, Sanjay Krishna
Electrical and Computer Engineering Faculty Research and Publications
In a recently demonstrated algorithmic spectral-tuning technique by Jang et al. [Opt. Express 19, 19454-19472, (2011)], the reconstruction of an object’s emissivity at an arbitrarily specified spectral window of interest in the long-wave infrared region was achieved. The technique relied upon forming a weighted superposition of a series of photocurrents from a quantum dots-in-a-well (DWELL) photodetector operated at discrete static biases that were applied serially. Here, the technique is generalized such that a continuously varying biasing voltage is employed over an extended acquisition time, in place using a series of fixed biases over each sub-acquisition time, which totally …
New Perspective On Passively Quenched Single Photon Avalanche Diodes: Effect Of Feedback On Impact Ionization,
2012
University of New Mexico
New Perspective On Passively Quenched Single Photon Avalanche Diodes: Effect Of Feedback On Impact Ionization, David A. Ramirez, Majeed M. Hayat, Graham J. Rees, Xudong Jiang, Mark A. Itzler
Electrical and Computer Engineering Faculty Research and Publications
Single-photon avalanche diodes (SPADs) are primary devices in photon counting systems used in quantum cryptography, time resolved spectroscopy and photon counting optical communication. SPADs convert each photo-generated electron hole pair to a measurable current via an avalanche of impact ionizations. In this paper, a stochastically self-regulating avalanche model for passively quenched SPADs is presented. The model predicts, in qualitative agreement with experiments, three important phenomena that traditional models are unable to predict. These are: (1) an oscillatory behavior of the persistent avalanche current; (2) an exponential (memoryless) decay of the probability density function of the stochastic quenching time of the …
A New Ensemble Learning Method For Temporal Pattern Identification,
2012
Marquette University
A New Ensemble Learning Method For Temporal Pattern Identification, Wenjing Zhang, Xin Feng
Electrical and Computer Engineering Faculty Research and Publications
In this paper we present a method for identification of temporal patterns predictive of significant events in a dynamic data system. A new hybrid model using Reconstructed Phase Space (MRPS) and Hidden Markov Model (HMM) is applied to identify temporal patterns. This method constructs phase space embedding by using individual embedding of each variable sequences. We also employ Hidden Markov Models (HMM) to the multivariate sequence data to categorize multi-dimensional data into three states, e.g. normal, patterns and events. A support vector machine optimization method is used to search an optimal classifier to identify temporal patterns that are predictive of …
A Very Robust Algan/Gan Hemt Technology To High Forward Gate Bias And Current,
2012
United States Air Force Institute of Technology
A Very Robust Algan/Gan Hemt Technology To High Forward Gate Bias And Current, Bradley D. Christiansen, Eric R. Heller, Ronald A. Coutu Jr., Ramakrishna Vetury, Jeffrey B. Shealy
Electrical and Computer Engineering Faculty Research and Publications
Reports to date of GaN HEMTs subjected to forward gate bias stress include varied extents of degradation. We report an extremely robust GaN HEMT technology that survived—contrary to conventional wisdom—high forward gate bias (+6 V) and current (>1.8 A/mm) for >17.5 hours exhibiting only a slight change in gate diode characteristic, little decrease in maximum drain current, with only a 0.1 V positive threshold voltage shift, and, remarkably, a persisting breakdown voltage exceeding 200 V.
A Simulation Analysis Of Photovoltaic Ac Module Integrated Converters In Parallel, Under Controlled Edge Shading Conditions,
2012
Technological University Dublin
A Simulation Analysis Of Photovoltaic Ac Module Integrated Converters In Parallel, Under Controlled Edge Shading Conditions, Lynette O'Callaghan, Mick Mckeever, Brian Norton
Conference Papers
A DC and AC power simulation comparison of: a Photovoltaic (PV) array with a modular, parallel, AC converter configuration; and a series, string configuration with a central AC converter, is presented. The systems are simulated using a comprehensive range of edge shading scenarios and irradiance conditions. Power control and transformation circuitry must be designed for shade and module mismatch tolerance to prevent over-proportional power to shade losses, as average losses from Building Integrated PV (BIPV) systems are approximately 20 to 25%, due to shade, mismatch, differences in orientation and inclination, and temperature effects. 59.4% of the simulations showed gains in …
Distributed Formal Concept Analysis Algorithms Based On An Iterative Mapreduce Framework,
2012
Technological University Dublin
Distributed Formal Concept Analysis Algorithms Based On An Iterative Mapreduce Framework, Ruairí De Fréin, Biao Xu, Eric Robson, Mícheál Ó Fóghlú
Conference papers
While many existing formal concept analysis algorithms are efficient, they are typically unsuitable for distributed implementation. Taking the MapReduce (MR) framework as our inspiration we introduce a distributed approach for performing formal concept mining. Our method has its novelty in that we use a light-weight MapReduce runtime called Twister which is better suited to iterative algorithms than recent distributed approaches. First, we describe the theoretical foundations underpinning our distributed formal concept analysis approach. Second, we provide a representative exemplar of how a classic centralized algorithm can be implemented in a distributed fashion using our methodology: we modify Ganter’s classic algorithm …
Development Of Student Centred Knowledge Management System Based In A Higher Education Institution,
2012
Technological University Dublin
Development Of Student Centred Knowledge Management System Based In A Higher Education Institution, Chong Liu
Dissertations
With the emergence of a knowledge society and of information technology, knowledge has become a key resource to develop a sustained economy. It is a vital word in the Knowledge Management area (Awad & Ghaziri, 2004). Knowledge Management has also become vital to help knowledge organizations seek a competitive advantage. It also encourages members of organization to share knowledge and improve the organization‘s efficiency, performance, and competitiveness (Shin, 2004). Therefore, an increasing number of organizations have realized the necessity of knowledge management. Especially, the Higher Education Institute (HEI) as the extraordinary ―business‖ will be suitable for implementing knowledge management approaches …
E-Learning And Knowledge Management: The Development Of An E-Learning System For Organisational Training,
2012
Technological University Dublin
E-Learning And Knowledge Management: The Development Of An E-Learning System For Organisational Training, Alan Muhire
Dissertations
Information technology has major role in most successful companies and organisations around the world, most companies are using IT to reduce operation cost, while improving customer service by providing service twenty four hours, seven days a week and improving communication that helps keep pace with competitors. In most companies and organisation training is a process carried out on a regular basis; the quality of training offered to employee will be reflected on how knowledgeable the staff will become resulting in the organisation becoming more successful. As organisations and companies are currently interested in improving knowledge management, employees are equally working …
An Investigation Into Obstacles Effecting The Use Of Support Technology For Accommodation Facilitation In Third Level Education,
2012
Technological University Dublin
An Investigation Into Obstacles Effecting The Use Of Support Technology For Accommodation Facilitation In Third Level Education, Conor Brennan
Dissertations
The profile of students attending third level education in Ireland has changed over the past number of years. More non-traditional students have entered mainstream education. These non-traditional students may be mature students, students whose first language is not English and students with disabilities. In the 2010-2011 academic session 6,932 students with disabilities were enrolled in third level education. This represent 3.9%(AHEAD 2011) of all students enrolled in third level education, which constitutes a 10% increase on 2009-2010. This increase is putting pressure on an already strained system. Efforts have been made to educate and inform lecturers and teaching staff on …
