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Articles 571 - 600 of 793

Full-Text Articles in Physical Sciences and Mathematics

Gain Of A Single Gas Electron Multiplier, Mythra Varun Nemallapudi Aug 2012

Gain Of A Single Gas Electron Multiplier, Mythra Varun Nemallapudi

Graduate Theses and Dissertations

Gas Electron Multiplier (GEM) is a gaseous detector used in particle detection and is

known for its high rate capability. Ever since its invention in 1997, GEM was applied in

many areas and recently has been proposed to be installed in the CMS high η regions for

upgrade at LHC, CERN. A complete understanding of the working and gain behaviour does

not exist. GEM gain is influenced by charging up and this has been variedly interpreted

in literature lacking consensus. I have attempted in this work through simulations and

measurements to achieve a better understanding of single GEM gain and …


Fast And Efficient Classification, Tracking, And Simulation In Wireless Sensor Networks, Hao Jiang Aug 2012

Fast And Efficient Classification, Tracking, And Simulation In Wireless Sensor Networks, Hao Jiang

All Dissertations

Wireless sensor networks are composed of large numbers of resource-lean sensors that collect low-level inputs from the physical world. The applications present challenges for programmers. On the one hand, lightweight algorithms are required given the limited capacity of the constituent devices. On the other, the algorithms must be scalable to accommodate large networks. In this thesis, we focus on the design and implementation of fast and lean (yet scalable) algorithms for classification, simulation, and target tracking in the context of wireless sensor networks. We briefly consider each of these challenges in turn.
The first challenge is to achieve high precision …


Precis: A Design-Time Precision Analysis Tool, Mark L. Chang, Scott Hauck Jul 2012

Precis: A Design-Time Precision Analysis Tool, Mark L. Chang, Scott Hauck

Mark L. Chang

Currently, few tools exist to aid the FPGA developer in translating an algorithm designed for a general-purpose-processor into one that is precision-optimized for FPGAs. This task requires extensive knowledge of both the algorithm and the target hardware. We present a design-time tool, Precis, which assists the developer in analyzing the precision requirements of algorithms specified in MATLAB. Through the combined use of simulation, user input, and program analysis, we demonstrate a methodology for precision analysis that can aid the developer in focusing their manual precision optimization efforts.


Management Of Land Use Land Cover Through The Application Of Remote Sensing, Geographic Information Systems And Simulation, Praveen Jha Jun 2012

Management Of Land Use Land Cover Through The Application Of Remote Sensing, Geographic Information Systems And Simulation, Praveen Jha

Graduate Doctoral Dissertations

Deforestation and degradation of forest areas, including those in the Protected Areas (PAs), are major concerns in India. There were 2 broad objectives of the study: the technological objective pertained to the development of state-of-art programs that could serve as Decision Support Systems while finalizing plans and policy interventions, while the other objective aimed at generating geo-spatial data in 2 PAs. A part of the Eastern Himalaya biodiversity hotspot, Manas Tiger Reserve (MTR), Assam, India having an area of 2837.12 sq km and an important part of Rajaji-Corbett Tiger Conservation Unit, Rajaji National Park (RNP), Uttarakhand, India, having an area …


Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew Mccarty, Chris Rasmussen Jun 2012

Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew Mccarty, Chris Rasmussen

Aerospace Engineering

This report details the research, design, construction, and testing of a pyrotechnic shock simulation apparatus for spacecraft applications. The apparatus was developed to be used in the Space Environments Lab at California Polytechnic State University. It will be used for testing spacecraft components with dimensions up to 24”x12”x12” as well as CubeSats. Additionally, it may be used as an instructional or demonstrational tool in the Aerospace Department’s space environments course. The apparatus functions by way of mechanical impact of an approximately 20 lb stainless steel swinging hammer. Tests were performed to verify the simulator’s functionality. Suggestions for improvement and further …


Modeling The Effect Of Environmental Factors On The Spread Of Bacterial Disease In An Economically Structured Population, Ram Naresh, Surabhi Pandey Jun 2012

Modeling The Effect Of Environmental Factors On The Spread Of Bacterial Disease In An Economically Structured Population, Ram Naresh, Surabhi Pandey

Applications and Applied Mathematics: An International Journal (AAM)

We have proposed and analyzed a nonlinear mathematical model for the spread of bacterial disease in an economically structured population (rich and poor) including the role of vaccination. It is assumed that rich susceptible get infected through direct contact with infectives in the same class and with infectives from the poor class who work as service providers in the houses of rich people, living in much cleaner environment. The susceptible in the poor class are assumed to become infected through direct contact with infectives in the same class as well as by bacteria present in their own environment, degraded due …


Light Field And Water Clarity Simulation Of Natural Environments In Laboratory Conditions, Shachak Pe'eri, Glenn T. Shwaery Jun 2012

Light Field And Water Clarity Simulation Of Natural Environments In Laboratory Conditions, Shachak Pe'eri, Glenn T. Shwaery

Center for Coastal and Ocean Mapping

Simulation of natural oceanic conditions in a laboratory setting is a challenging task, especially when that environment can be miles away. We present an attempt to replicate the solar radiation expected at different latitudes with varying water clarity conditions up to 30 m in depth using a 2.5 m deep engineering tank at the University of New Hampshire. The goals of the study were: 1) to configure an underwater light source that produced an irradiance spectrum similar to natural daylight with the sun at zenith and at 60° under clear atmospheric conditions, and 2) to monitor water clarity as a …


Point-Spread Function Assessment Of Sg-Dbr Based Swept Source For Oct Imaging, David Wilkey Gilbert Jun 2012

Point-Spread Function Assessment Of Sg-Dbr Based Swept Source For Oct Imaging, David Wilkey Gilbert

Master's Theses

Swept Source Optical Coherence Tomography (SS-OCT) is a medical imaging technique that requires high repetition rate, widely-tunable coherent laser sources. Sampled grating distributed Bragg reflector (SG-DBR) lasers are proven in telecom applications and are expected to fulfill the requirements for SS-OCT at a significantly lower cost than alternative solutions.

Constructed entirely on a semiconductor substrate, SG-DBR lasers require four synchronized waveforms to modulate the output wavelength and intensity. Because of this unique tuning mechanism, there are a number of systematic and noise sources that can affect the quality of the OCT point-spread function (PSF). Based on these noise sources, software …


Simulating Non-Normal Distributions With Specified L-Moments And L-Correlations, Todd C. Headrick, Mohan D. Pant May 2012

Simulating Non-Normal Distributions With Specified L-Moments And L-Correlations, Todd C. Headrick, Mohan D. Pant

Mohan Dev Pant

This paper derives a procedure for simulating continuous non-normal distributions with specified L-moments and L-correlations in the context of power method polynomials of order three. It is demonstrated that the proposed procedure has computational advantages over the traditional product-moment procedure in terms of solving for intermediate correlations. Simulation results also demonstrate that the proposed L-moment-based procedure is an attractive alternative to the traditional procedure when distributions with more severe departures from normality are considered. Specifically, estimates of L-skew and L-kurtosis are superior to the conventional estimates of skew and kurtosis in terms of both relative bias and relative standard error. …


Using The R Library Rpanel For Gui-Based Simulations In Introductory Statistics Courses, Ryan M. Allison May 2012

Using The R Library Rpanel For Gui-Based Simulations In Introductory Statistics Courses, Ryan M. Allison

Statistics

As a student, I noticed that the statistical package R (http://www.r-project.org) would have several benefits of its usage in the classroom. One benefit to the package is its free and open-source nature. This would be a great benefit for instructors and students alike since it would be of no cost to use, unlike other statistical packages. Due to this, students could continue using the program after their statistical courses and into their professional careers. It would be good to expose students while they are in school to a tool that professionals use in industry. R also has powerful …


Statistical Inferences For Lomax Distribution Based On Record Values (Bayesian And Classical), Parviz Nasiri, Saman Hosseini May 2012

Statistical Inferences For Lomax Distribution Based On Record Values (Bayesian And Classical), Parviz Nasiri, Saman Hosseini

Journal of Modern Applied Statistical Methods

A maximum likelihood estimation (MLE) based on records is obtained and a proper prior distribution to attain a Bayes estimation (both informative and non-informative) based on records for quadratic loss and squared error loss functions is also calculated. The study considers the shortest confidence interval and Highest Posterior Distribution confidence interval based on records, and using Mean Square Error MSE criteria for point estimation and length criteria for interval estimation, their appropriateness to each other is examined.


Retention Of Statistical Concepts In A Preliminary Randomization-Based Introductory Statistics Curriculum, Nathan L. Tintle, Kylie Topliff, Jill Vanderstoep, Vicki-Lynn Holmes, Todd Swanson May 2012

Retention Of Statistical Concepts In A Preliminary Randomization-Based Introductory Statistics Curriculum, Nathan L. Tintle, Kylie Topliff, Jill Vanderstoep, Vicki-Lynn Holmes, Todd Swanson

Faculty Work Comprehensive List

Previous research suggests that a randomization-based introductory statistics course may improve student learning compared to the consensus curriculum. However, it is unclear whether these gains are retained by students post-course. We compared the conceptual understanding of a cohort of students who took a randomization-based curriculum (n = 76) to a cohort of students who used the consensus curriculum (n = 79). Overall, students taking the randomization-based curriculum showed higher conceptual retention in areas emphasized in the curriculum, with no significant decrease in conceptual retention in other areas. This study provides additional support for the use of randomization-methods in teaching introductory …


A Radio Link Quality Model And Simulation Framework For Improving The Design Of Embedded Wireless Systems, Sally Wahba May 2012

A Radio Link Quality Model And Simulation Framework For Improving The Design Of Embedded Wireless Systems, Sally Wahba

All Dissertations

Despite the increasing application of embedded wireless systems, developers face numerous challenges during the design phase of the application life cycle. One of the critical challenges is ensuring performance reliability with respect to radio link quality. Specifically, embedded links experience exaggerated link quality variation, which results in undesirable wireless performance characteristics. Unfortunately, the resulting post-deployment behaviors often necessitate network redeployment.
Another challenge is recovering from faults that commonly occur in embedded wireless systems, including node failure and state corruption. Self-stabilizing algorithms can provide recovery in the presence of such faults. These algorithms guarantee the eventual satisfaction of a given state …


Peer-To-Peer Simulation Of Massive Virtual Environments, James Dean Mathias May 2012

Peer-To-Peer Simulation Of Massive Virtual Environments, James Dean Mathias

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Massively multiplayer games make up a large and growing segment of the computer game industry. One of the best known examples of these games is World of Warcraft, developed and published by Activision Blizzard. World of Warcraft boasts a subscriber base of over eleven million active subscribers, earning an estimated $1 billion dollars in 2010.

Some of the core issues for companies that publish these games are the cost of the computers, Internet bandwidth usage, and supporting technical staff. These costs easily reach hundreds of thousands of dollars each month, and in the case of World of Warcraft, millions of …


Parallel Diffusion-Limited Aggregation, H Kaufman, A Vespignani, B B. Mandelbrot, L Woog Apr 2012

Parallel Diffusion-Limited Aggregation, H Kaufman, A Vespignani, B B. Mandelbrot, L Woog

Alessandro Vespignani

We present methods for simulating very large diffusion-limited aggregation (DLA) clusters using parallel processing (PDLA). With our techniques, we have been able to simulate clusters of up to 130 million particles. The time required for generating a 100 million particle PDLA is approximately 13 h. The fractal behavior of these ''parallel'' clusters changes from a multiparticle aggregation dynamics to the usual DLA dynamics. The transition is described by simple scaling assumptions that define a characteristic cluster size separating the two dynamical regimes. We also use DLA clusters as seeds for parallel processing. In this case, the transient regime disappears and …


Performance Evaluation Of Optimal Rate Allocation Models For Wireless Networks, Ryan Michael Padilla Apr 2012

Performance Evaluation Of Optimal Rate Allocation Models For Wireless Networks, Ryan Michael Padilla

Theses and Dissertations

Convex programming is used in wireless networks to optimize the sending or receiving rates of links or flows in a network. This kind of optimization problem is formulated into a rate allocation problem, where each node in the network will distributively solve the convex problem and all links or flows will converge to their optimal rate. The objective function and constraints of these problems are represented in a simplified model of contention, interference, and sending or receiving rates. The Partial Interference model is an optimal rate allocation model for use in wireless mesh networks that has been shown to be …


Simulation Chamber For Space Environment Survivability Testing, Lisa Montierth, Robert H. Johnson, John R. Dennison, James Dyer Mar 2012

Simulation Chamber For Space Environment Survivability Testing, Lisa Montierth, Robert H. Johnson, John R. Dennison, James Dyer

All Physics Faculty Presentations

A vacuum chamber was designed and built that simulates the space environment making possible the testing of material modification due to exposure of solar radiation. Critical environmental components required include an ultra high vacuum (10-9 Torr), a UV/VIS/NIR solar spectrum source, an electron gun and charge plasma, temperature extremes, and long exposure duration. To simulate the solar spectrum, a solar simulator was attached to the chamber with a range of 200nm to 2000nm. The exposure time can be accelerated by scaling the solar intensity up to four suns. A Krypton lamp imitates the 120 nm ultraviolet hydrogen Lymann alpha emission …


Using Agent-Based Models To Understand Multi-Operator Supervisory Control, Yisong Guo Mar 2012

Using Agent-Based Models To Understand Multi-Operator Supervisory Control, Yisong Guo

Theses and Dissertations

As technology advances, many practical applications require human-controlled robots. For such applications, it is useful to determine the optimal number of robots an operator should control to maximize human efficiency given different situations. One way to achieve this is through computer simulations of team performance. In order to factor in various parameters that may affect team performance, an agent-based model will be used. Agent-based modeling is a computational method that enables a researcher to create, analyze, and experiment with models composed of agents that interact within an environment [12]. We construct an agent-based model of humans interacting with robots, and …


Sample Size Calculations For Roc Studies: Parametric Robustness And Bayesian Nonparametrics, Dunlei Cheng, Adam J. Branscum, Wesley O. Johnson Jan 2012

Sample Size Calculations For Roc Studies: Parametric Robustness And Bayesian Nonparametrics, Dunlei Cheng, Adam J. Branscum, Wesley O. Johnson

Dunlei Cheng

Methods for sample size calculations in ROC studies often assume independent normal distributions for test scores among the diseased and non-diseased populations. We consider sample size requirements under the default two-group normal model when the data distribution for the diseased population is either skewed or multimodal. For these two common scenarios we investigate the potential for robustness of calculated sample sizes under the mis-specified normal model and we compare to sample sizes calculated under a more flexible nonparametric Dirichlet process mixture model. We also highlight the utility of flexible models for ROC data analysis and their importance to study design. …


The Inexorable Resistance Of Inertia Determines The Initial Regime Of Drop Coalescence, Joseph Paulsen, Justin C. Burton, Sidney R. Nagel, Santosh Appathurai, Michael T. Harris, Osman A. Basaran Jan 2012

The Inexorable Resistance Of Inertia Determines The Initial Regime Of Drop Coalescence, Joseph Paulsen, Justin C. Burton, Sidney R. Nagel, Santosh Appathurai, Michael T. Harris, Osman A. Basaran

Physics - All Scholarship

Drop coalescence is central to diverse processes involving dispersions of drops in industrial, engineering, and scientific realms. During coalescence, two drops first touch and then merge as the liquid neck connecting them grows from initially microscopic scales to a size comparable to the drop diameters. The curvature of the interface is infinite at the point where the drops first make contact, and the flows that ensue as the two drops coalesce are intimately coupled to this singularity in the dynamics. Conventionally, this process has been thought to have just two dynamical regimes: a viscous and an inertial regime with a …


Simulating Non-Normal Distributions With Specified L-Moments And L-Correlations, Todd C. Headrick, Mohan D. Pant Jan 2012

Simulating Non-Normal Distributions With Specified L-Moments And L-Correlations, Todd C. Headrick, Mohan D. Pant

Todd Christopher Headrick

This paper derives a procedure for simulating continuous non-normal distributions with specified L-moments and L-correlations in the context of power method polynomials of order three. It is demonstrated that the proposed procedure has computational advantages over the traditional product-moment procedure in terms of solving for intermediate correlations. Simulation results also demonstrate that the proposed L-moment-based procedure is an attractive alternative to the traditional procedure when distributions with more severe departures from normality are considered. Specifically, estimates of L-skew and L-kurtosis are superior to the conventional estimates of skew and kurtosis in terms of both relative bias and relative standard error. …


Data Envelopment Analysis In The Presence Of Measurement Error: Case Study From The National Database Of Nursing Quality Indicators (Ndnqi), Byron J. Gajewski, Robert Lee, Nancy Dunton Jan 2012

Data Envelopment Analysis In The Presence Of Measurement Error: Case Study From The National Database Of Nursing Quality Indicators (Ndnqi), Byron J. Gajewski, Robert Lee, Nancy Dunton

Byron J Gajewski

Data envelopment analysis (DEA) is the most commonly used approach for evaluating healthcare efficiency [B. Hollingsworth, The measurement of efficiency and productivity of health care delivery. Health Economics 17(10) (2008), pp. 1107–1128], but a long-standing concern is that DEA assumes that data are measured without error. This is quite unlikely, and DEA and other efficiency analysis techniques may yield biased efficiency estimates if it is not realized [B.J. Gajewski, R. Lee, M. Bott, U. Piamjariyakul, and R.L. Taunton, On estimating the distribution of data envelopment analysis efficiency scores: an application to nursing homes’ care planning process. Journal of Applied Statistics …


The Quotient Of The Beta-Weibull Distribution, Nonhle Channon Mdziniso Jan 2012

The Quotient Of The Beta-Weibull Distribution, Nonhle Channon Mdziniso

Theses, Dissertations and Capstones

A new class of distributions recently developed involves the logit of the beta distribution. Among this class of distributions are, the beta-Normal (Eugene et al. [15]); beta-Gumbel (Nadarajah and Kotz [18]); beta-Exponential (Nadarajah and Kotz [19]); beta-Weibull (Famoye et al. [6]); beta-Rayleigh (Akinsete and Lowe [3]); beta-Laplace (Kozubowshi and Nadarajah [20]); and beta-Pareto (Akinsete et al. [4]), among a few others. Many useful statistical properties arising from these distributions and their applications to real life data have been discussed in literature. One approach by which a new statistical distribution is generated is by the transformation of random variables having known …


Simulation And Phases Of Macroscopic Particles In Vortex Flow, Heath Eric Rice Jan 2012

Simulation And Phases Of Macroscopic Particles In Vortex Flow, Heath Eric Rice

Electronic Theses and Dissertations

Granular materials are an interesting class of media in that they exhibit many disparate characteristics depending on conditions. The same set of particles may behave like a solid, liquid, gas, something in-between, or something completely unique depending on the conditions. Practically speaking, granular materials are used in many aspects of manufacturing, therefore any new information gleaned about them may help refine these techniques. For example, learning of a possible instability may help avoid it in practical application, saving machinery, money, and even personnel. To that end, we intend to simulate a granular medium under tornado-like vortex airflow by varying particle …


Parameters Controlling Emission Of Terahertz Frequency Electromagnetic Radiation From Inas And Gaas: An Ensemble Monte Carlo Simulation Study, David Laurence Cortie, Roger A. Lewis Jan 2012

Parameters Controlling Emission Of Terahertz Frequency Electromagnetic Radiation From Inas And Gaas: An Ensemble Monte Carlo Simulation Study, David Laurence Cortie, Roger A. Lewis

Australian Institute for Innovative Materials - Papers

The generation, manipulation and detection of terahertz-frequency electromagnetic radiation are topics of great current theoretical and experimental interest. In particular, the coherent generation and detection of ultrashort pulses of terahertz radiation has opened up the field of terahertz time-domain spectroscopy, which permits the simultaneous measurement of amplitude and phase of the terahertz electric field. In this paper, the emission of terahertz radiation from bare semiconductor surfaces following photoexcitation by ultrashort pulses of near-infrared radiation is studied using ensemble Monte Carlo simulations. The simulation allows us to examine separately distinct scattering mechanisms and to vary the materials parameters of bandgap, absorption …


Discrete Event Simulation Of Elevator Systems, Sasi Bharath Desai Jan 2012

Discrete Event Simulation Of Elevator Systems, Sasi Bharath Desai

CMC Senior Theses

The intent of this paper is to present the reader with a simple comparison of two systems of vertical transportation. Vertical transportation is a a relatively new field and is the subject of much interest in today's world. As buildings get taller and real estate becomes more expensive, the need to find a quick, efficient system with a small footprint becomes important. By performing a simulation and subjecting the two systems under study to similar traffic conditions, one can determine the effectiveness of one system relative to the other. Additionally, we look at the effects of changing various system attributes …


Parsing The Relationship Between Baserunning And Batting Abilities Within Lineups, Ben S. Baumer, James Piette, Brad Null Jan 2012

Parsing The Relationship Between Baserunning And Batting Abilities Within Lineups, Ben S. Baumer, James Piette, Brad Null

Statistical and Data Sciences: Faculty Publications

A baseball team's offensive prowess is a function of two types of abilities: batting and baserunning. While each has been studied extensively in isolation, the effects of their interaction is not well understood. We model offensive output as a scalar function f of an individual player's batting and baserunning profile z. Each of these profiles is in turn estimated from Retrosheet data using heirarchical Bayesian models. We then use the SimulOutCome simulation engine as a method to generate values of f(z) over a fine grid of points. Finally, for each of several methods of taking the extra base, we graphically …


Small Scale Simulation Chamber For Space Environment Survivability Testing, Robert H. Johnson, Lisa D. Montierth, John R. Dennison, James S. Dyer, Ethan Lindstrom, Alex Chanson Jan 2012

Small Scale Simulation Chamber For Space Environment Survivability Testing, Robert H. Johnson, Lisa D. Montierth, John R. Dennison, James S. Dyer, Ethan Lindstrom, Alex Chanson

All Physics Faculty Publications

A versatile vacuum system for long duration testing of materials modifications due to exposure to simulated space environment conditions has been designed and built. The chamber is particularly well suited for cost-effective tests of multiple small scale materials samples over prolonged exposure. Critical environmental components simulated include neutral gas [ultrahigh vacuum (10-7 Pa) to ambient], FUV/UV/VIS/NIR solar spectrum, electron plasma fluxes, and temperature. The UV/VIS/NIR solar spectrum is simulated using an external, normally incidence and collimated class AAA Solar Simulator source, with standard Air Mass Zero (AM0) filters to shape the incident radiation spectrum. This Xe arc discharge tube source …


Modelling Β2ar Regulation, Sharat J. Vayttaden Dec 2011

Modelling Β2ar Regulation, Sharat J. Vayttaden

Dissertations & Theses (Open Access)

The β2 adrenergic receptor (β2AR) regulates smooth muscle relaxation in the vasculature and airways. Long- and Short-acting β-agonists (LABAs/SABAs) are widely used in treatment of chronic obstructive pulmonary disorder (COPD) and asthma. Despite their widespread clinical use we do not understand well the dominant β2AR regulatory pathways that are stimulated during therapy and bring about tachyphylaxis, which is the loss of drug effects. Thus, an understanding of how the β2AR responds to various β-agonists is crucial to their rational use. Towards that end we have developed deterministic models that explore the mechanism of drug- induced β2AR regulation. These mathematical models …


Six D.O.F Haptic Rendered Simulation Of The Peg-In-Hole Assembly, Shen Dong, Fazel Naghdy, Yan Chen Oct 2011

Six D.O.F Haptic Rendered Simulation Of The Peg-In-Hole Assembly, Shen Dong, Fazel Naghdy, Yan Chen

Professor Fazel Naghdy

A new paradigm for programming of robotics manipulator to perform complex constrained motion tasks is being studied. The teaching of the manipulation skills to the machine starts by demonstmting those skills in a haptic -rendered virtual environment. Position and contact force and torque data generated in the virtual environment combined with a priori knowledge about the task is used to identify and learn the skills in the newly demonstrated tasks and then to reproduce them in the robotics system. The peg-in-hole insertion problem is used as a case study. In the ftrst implementation of the virtual manipulahon envlfonment, a three …