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Theses and Dissertations

1993

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Articles 61 - 90 of 101

Full-Text Articles in Physical Sciences and Mathematics

Handwritten Word Recognition Based On Fourier Coefficients, Gary F. Shartle Dec 1993

Handwritten Word Recognition Based On Fourier Coefficients, Gary F. Shartle

Theses and Dissertations

A machine which can read unconstrained words remains an unsolved problem. For example, automatic entry o handwritten documents into a computer is yet to be accomplished. Most systems attempt to segment letters o a word and read words one character at a time. Segmenting a handwritten word is very difficult and often, the confidence of the results is low. Another method which avoids segmentation altogether is to treat each word as a whole. This research investigates the use of Fourier Transform coefficients, computed from the whole word, for the recognition of handwritten words. To test this concept, the particular pattern …

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Performance Impacts For Actuator Misalignments And Failures In Large- Aperture Adaptive-Optic Telescopes, Timothy D. Hogan Dec 1993

Performance Impacts For Actuator Misalignments And Failures In Large- Aperture Adaptive-Optic Telescopes, Timothy D. Hogan

Theses and Dissertations

Large-aperture telescopes require adaptive optics in order to compensate for atmospheric turbulence which would otherwise negate the resolution advantages of using large apertures. This investigation analyzes the impacts of misalignments and failures, in the deformable mirror actuators, upon the performance of such systems. A numerical simulation of a standard adaptive optics system is used to generate characteristic optical transfer function OTF and signal-to-noise ratio SNR performance metrics. The performance impacts of the misalignments are shown to be dependent upon the Fried parameter effective telescope diameter, the source object brightness, and the control system time delay. The degree of performance degradation …

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Hyperspectral Analysis Of Space Objects: Signal To Noise Evaluation, Daniel Hrovat Dec 1993

Hyperspectral Analysis Of Space Objects: Signal To Noise Evaluation, Daniel Hrovat

Theses and Dissertations

Hyperspectral analysis of space objects is being considered as a means of enhancing Space Object Identification. SOI capabilities. This study develops a mathematical simulation based on fundamental radiometry principles to evaluate the feasibility of hyperspectral analysis of space objects. The study uses Signal to Noise Ratio SNR as the basis for the feasibility evaluation, and addresses the question Is there enough target signal in narrow wavelength bandwidths to conduct hyperspectral measurements of space objects The analysis characterizes the target signal and noise sources using fundamental radiometry, and develops a flexible radiometry model which calculates the target signal count rate, and …

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System Design Analysis Of A Lightweight Laser Satellite Terminal, Brian C. Page Dec 1993

System Design Analysis Of A Lightweight Laser Satellite Terminal, Brian C. Page

Theses and Dissertations

This study investigated the technological feasibility of a man- portable satellite laser communications system. Areas of interest were an end- to-end system analysis on the communications link evaluation of atmospheric effects and evaluation of semi-conductor lasers as the laser source. A literature search revealed that satellite laser communication research is primarily directed at inter-satellite links. There have been some proposed systems for space-to-ground laser communications systems, but they all utilize large fixed ground stations. The focus of this research effort is directed at a small man-portable ground station capitalizing on recent advances in semiconductor laser devices. Baseline satellite communication systems …

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Object-Oriented Design And Implementation Of A Parallel Ada Simulation System, James T. Belford Nov 1993

Object-Oriented Design And Implementation Of A Parallel Ada Simulation System, James T. Belford

Theses and Dissertations

Simulations which model the behavior real world entities are often large and complex, and require frequent changes to the configuration. This research effort examines the benefits of using object-oriented techniques to develop a distributed simulation environment which supports modularity, modifiability, and portability. The components of the Parallel Discrete Event Simulation PDES environment are identified and modeled using the Rumbaugh modeling technique. From the model, a prototype implementation of a Parallel Ada Simulation Environment PASE is accomplished using Classic Ada. A system interface for the Intel ipsc2 Hypercube was developed to illustrate the concepts of modularity and portability. In addition, the …

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On The Automation Of Object-Oriented Requirements Analysis, Nancy L. Crowley Sep 1993

On The Automation Of Object-Oriented Requirements Analysis, Nancy L. Crowley

Theses and Dissertations

The research investigated the possibility that an object-oriented requirements analysis (OORA) specification model can be represented in a computer system and used as a basis for the elicitation of the information necessary for the development of an object-oriented specification for a particular problem. The proof-of-concept system developed is called the OORA automated Knowledge System (OAKS). OAKS contains a generic domain model that is modified to satisfy a particular problem in the domain. The core of OAKS is a reusable domain model, which represents a domain of interest. The domain model is used as a basis for user changes that are …

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Analytical Modeling Of Aquifer Decontamination By Pulsed Pumping When Contaminant Transport Is Affected By Rate-Limited Sorption And Desorption, Thomas A. Adams, Robert C. Viramontes Sep 1993

Analytical Modeling Of Aquifer Decontamination By Pulsed Pumping When Contaminant Transport Is Affected By Rate-Limited Sorption And Desorption, Thomas A. Adams, Robert C. Viramontes

Theses and Dissertations

This research explores radially convergent contaminated transport in an aquifer towards an extraction well. This thesis presents the equations governing the transport of a contaminant during aquifer remediation by pulsed pumping. Contaminant transport is assumed to be affected by radial advection, dispersion, and sorption/desorption. Sorption is assumed to be either equilibrium or rate-limited, with the rate-limitation described by either a first-order law, or by Fickian diffusion of contaminant through layered, cylindrical, or spherical immobile water regions. The equations are derived using an arbitrary initial distribution of contaminant in both the mobile and immobile regions, and they are analytically solved in …

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Vadose Zone Contamination Measurement And Modeling, Thomas A. Reeder Sep 1993

Vadose Zone Contamination Measurement And Modeling, Thomas A. Reeder

Theses and Dissertations

This thesis investigated the effects of the slow sorption mechanism on the transport of volatile organic contaminants in the vadose zone. Recent research has shown that slow sorption may have a significant impact on the transport of volatile organic compounds in the subsurface. Specifically, this document examined the effects of slow sorption on the Vapor Extraction System (VES) and the Purge and Trap Measurement System. It was found that the slow sorption of organic molecules on soil may profoundly influence the efficiency of VES and purge and trap. In addition, this thesis investigated possible alternatives to purge and trap, including …

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A Plan For Coordinating Department Of Defense Emissions Trading, Charles H. Weir Sep 1993

A Plan For Coordinating Department Of Defense Emissions Trading, Charles H. Weir

Theses and Dissertations

The original purpose of this research was to develop a plan to coordinate emissions trading between DoD installations. During the course of this research, findings indicated that restrictions on emissions trading would make such a plan of limited applicability. However, findings did indicate the need for a tool to assist managers with selecting the netting, offset, and banking emissions trading alternatives. Developing this tool became the objective of this research. This objective was fulfilled by developing a management guide to assist environmental managers with selecting the emissions trading alternatives netting, banking, and offsets. Background information was collected by examining literature …

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A Parametric Regression Of The Cost Of Base Realignment Action (Cobra) Model, Douglas Hardman, Michael Nelson Sep 1993

A Parametric Regression Of The Cost Of Base Realignment Action (Cobra) Model, Douglas Hardman, Michael Nelson

Theses and Dissertations

This study develops a parametric model that is capable of generating accurate estimates of the costs to close Air Force installations. The new model is based upon, but much simpler to use than, the Cost of Base Realignment Action (COBRA) model. COBRA is an economic cost analysis model that requires a minimum of 250 inputs and as many as 700 inputs. The new parametric model requires just 10 input variables and was developed using least squares multiple regression. Comparison of the new parametric model to COBRA indicates that it captures 91 percent of the variance in cost estimates generated by …

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Photoluminescence Spectroscopy Of Zinc Germanium Diphosphide (Zngep2), Jack E. Mccrae Sep 1993

Photoluminescence Spectroscopy Of Zinc Germanium Diphosphide (Zngep2), Jack E. Mccrae

Theses and Dissertations

Zinc germanium diphosphide (ZnGeP2) is a chalcopyrite semiconductor with strong nonlinear optical properties and potential application to Air Force interests. The characteristics of this material have been studied using photoluminescence (PL) spectroscopy. The PL spectrum is dominated by transitions from the conduction band to a deep acceptor level, and features in the spectrum suggest that more than one transition is being observed. The PL is partially polarized, and the degree of polarization appears to differ for each feature in the spectrum. The relative PL intensity of these features are seen to depend upon the wavelength of the excitation …

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Evaluation Of The Total Petroleum Hydrocarbon Standard For Cleanup Of Petroleum Contaminated Sites, Rick A. Blaisdell, Mark E. Smallwood Sep 1993

Evaluation Of The Total Petroleum Hydrocarbon Standard For Cleanup Of Petroleum Contaminated Sites, Rick A. Blaisdell, Mark E. Smallwood

Theses and Dissertations

This study evaluated the TPH (total petroleum hydrocarbon) cleanup standard for petroleum contaminated soils (PCS). A survey of 13 state regulators was performed to characterize current standards and regulatory viewpoints on the use of a TPH versus a BTEX cleanup standard. The regulatory community considers the BTEX constituents the greatest threat to groundwater, yet expressed concern that the use of a compound specific standard, without an accompanying analysis for TPH, might result in residual soil contamination that may present risk. This study also evaluated the ratio of BTEX TPH in soil over time. Based on JP-4 contaminated site soil data, …

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Guidance For The Development Of Air Force Storm Water Sampling Programs, Jerry K. Weldon Iii, Roy T. Willis Sep 1993

Guidance For The Development Of Air Force Storm Water Sampling Programs, Jerry K. Weldon Iii, Roy T. Willis

Theses and Dissertations

The purpose of this research was to develop sampling guidance that will enable Air Force (AF) installations to conduct cost effective storm water sampling in accordance with current storm water regulations. Data on the techniques used by AF bases to obtain storm water samples for the AF group storm water permit application were collected and analyzed. This information was used to outline management and resource requirements associated with the implementation of NPDES storm water regulations. The use of in-house personnel, automatic sampling equipment, or a contractor to perform the field data collection was examined. An in-house manual approach to storm …

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A Decision Criteria To Select An Associative-Memory Organization That Minimizes The Execution Time Of A Mix Of Associative-Search Operations, David W. Banton Jun 1993

A Decision Criteria To Select An Associative-Memory Organization That Minimizes The Execution Time Of A Mix Of Associative-Search Operations, David W. Banton

Theses and Dissertations

The dissertation develops a decision criteria to select an associative-memory organization that minimizes the execution time of a mix of associative-search operations and a decision criteria to estimate the layout dimensions of each organization for a specified memory size. The dissertation reclassifies Feng's associative-search operations into three hardware-influenced categories: bit-position independent (BPI), record-content independent (RCI); bit-position dependent (BPD), RCI; and BPD, record-content dependent (RCD). It develops a relationship between the categories and three associative-memory organizations: the CAM, the bit-serial word-parallel associative memory (BSWPAM) , and the extreme-search associative memory (ESAM). A version of the CAM, three versions of the BSWPAM, …

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Radome Depolarization Effects On Monopulse Receiver Tracking Performance, Michael A. Temple Jun 1993

Radome Depolarization Effects On Monopulse Receiver Tracking Performance, Michael A. Temple

Theses and Dissertations

Boresight Error (BSE), defined as the angular deviation between the true position and the apparent position of a target as indicated by a radar, is an important figure of merit for a tracking radar. A significant contributor to system BSE is the protective radome. This research effort employed a GO technique to investigate the effects of a radome on BSE, expanding previous ray- trace receive techniques to include: (1) a uniquely defined/developed mathematical description for each surface within arbitrary multi-layer tapered radomes, (2) an 'ideal' taper function concept for obtaining optimum BSE prediction performance, (3) a generalized technique for calculating …

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Anns An X Window Based Version Of The Afit Neural Network Simulator, Ching-Seh Wu Jun 1993

Anns An X Window Based Version Of The Afit Neural Network Simulator, Ching-Seh Wu

Theses and Dissertations

This thesis presents an X Window based neural network simulation environment developed at Air Force Institute of Technology (AFIT) using the techniques of modern software engineering. This artificial neural network simulator is a tool running on Sun SPARCstations and supporting two user modes: end-users and client-programmers. End-users interact with neural network paradigms developed by client-programmers for the purpose of studying and analyzing the execution of a particular Neural Network (NN) paradigm, or class of NN algorithms. Client programmers maintain the system and use this environment for the development of new NN paradigms or algorithms for end-users. The development follows a …

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Design And Performance Evaluation Of A Gas Chromatograph Micromachined In A Single Crystal Silicon Substrate, Rocky R. Reston Mar 1993

Design And Performance Evaluation Of A Gas Chromatograph Micromachined In A Single Crystal Silicon Substrate, Rocky R. Reston

Theses and Dissertations

This investigation designed and developed a miniature gas chromatograph (GC) using silicon micromachining techniques. The GC is composed of a miniature sample injector (10 µl sample loop); a 0.9 m long, rectangular-shaped (300 µm width and 10 micrometers height) capillary column coated with a 0.2 µm thick copper phthalocyanine (CuPc) stationary phase; and a dual-detector scheme incorporating a CuPc-coated chemiresistor and a 125 µm diameter thermal conductivity detector bead. Micromachining was employed to fabricate the sample injector interface, the GC column, and the dual-detector cavity. A novel processing technique was developed to sublime the CuPc stationary phase coating on the …

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An Immersive Synthetic Environment For Observation And Interaction With A Large Volume Of Interest, Rex G. Haddix Iii Mar 1993

An Immersive Synthetic Environment For Observation And Interaction With A Large Volume Of Interest, Rex G. Haddix Iii

Theses and Dissertations

This thesis addresses the initial development of a Synthetic Battlebridge System designed to provide the user with a synthetic three- dimensional view of moving and stationary vehicles dispersed over a hundred thousand cubic mile volume. The system contains provisions to allow a user to view the battlefield either in the Polhemus LookingGlass™ fiber optic based high resolution head mounted display, a standard CRT, or through the Fake Space Labs BOOM2M™ high resolution monochrome display. Users can also video tape a session in the Synthetic Battlebridge System. A voice recognition system provides user interaction to the Synthetic Battlebridge System. Using a …

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Toward Reusable Graphics Components In Ada, Sam-Kyu Lim Mar 1993

Toward Reusable Graphics Components In Ada, Sam-Kyu Lim

Theses and Dissertations

This thesis demonstrates and illustrates a way of developing reusable graphics software components in Ada associated with a C++/C library. The work was carried out using object-oriented software development techniques that were used to analyze, design and implement a partial flight simulator. The objective of this thesis was to present a way of building reusable software components with Ada in a graphics application environment. An object-oriented approach was taken in the development of a set of reusable graphics software components for a flight simulator domain. A selection of a set of reusable software components came from domain analysis. These components …

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A Distributed Object-Oriented Database Application Design, Hsin-Feng Edward Wu Mar 1993

A Distributed Object-Oriented Database Application Design, Hsin-Feng Edward Wu

Theses and Dissertations

The purpose of this study is to analyze and develop a distributed object-oriented database management system (DOODBMS) application to support parallel software development of the Parallel Algorithms and Applications Group (PAAG) at AFIT. By following the software lifecycle of object-oriented paradigm, this thesis investigation is intended to generate requirements analysis, design, implementation, user interface design and implementation, and integration of the database application with the user interface. ITASCA, an existing DOODBMS platform, has been chosen to prototype the application for its distribution functionalities and object-oriented modeling power. The user interface of the database application is based on X-window OSF/Motif front-end …

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Development Of A Visual System Interface To Support A Domain-Oriented Application Composition System, Timothy L. Weide Mar 1993

Development Of A Visual System Interface To Support A Domain-Oriented Application Composition System, Timothy L. Weide

Theses and Dissertations

This research designed and prototyped a visual system interface to generate, display, and modify domain-oriented application specifications. A visual system interface, called the Architect Visual System Interface (AVSI), supplements a text-based environment, called Architect, previously developed by two other students. Using canonical formal specifications of domain objects, Architect rapidly composes these specifications into a software application and executes a prototype of that application as a means to demonstrate its correctness before any programming language specific code is generated. This thesis investigates visual techniques for populating, manipulating, viewing, and composing these software application specifications within the formal object base scheme required …

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Object-Oriented Database Access From Ada, Li Chou Mar 1993

Object-Oriented Database Access From Ada, Li Chou

Theses and Dissertations

Ada embodies many modern software engineering principles, namely, modifiability, efficiency, reliability, and understandability. Its powerful data abstraction allows programmers to easily model objects in the real world. A database management system (DBMS) provides long term storage. It provides a convenient and efficient environment to manipulate data. Currently, with Ada access to a DBMS is typically done through the use of a language extension and a preprocessor to convert the extensions to library calls appropriate for the DBMS. However, these systems are limited on more complex applications, such as computer-aided engineering design. Object-oriented design (OOD) is a new way of thinking …

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Self-Referenced Speckle Holography (Srsh) Image Reconstruction Performance, John R. Devey Mar 1993

Self-Referenced Speckle Holography (Srsh) Image Reconstruction Performance, John R. Devey

Theses and Dissertations

The Speckle Holography technique uses a series of short exposure images and associated wave front sensor measurements to reconstruct astronomical images. The reconstruction technique effectively boosts the amplitude of high spatial frequencies to allow for finer resolution of astronomical objects. A simulation package that calculates the optical transfer function (OTF) of a telescopic system was previously developed for the Phillips Laboratory. This software was modified slightly to provide the Speckle Holography system transfer function (STF) for a telescopic system under varying seeing conditions.

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Frequency Domain Speech Compression Using The Karhunen-Loeve Transform, Donald W. Dryley Mar 1993

Frequency Domain Speech Compression Using The Karhunen-Loeve Transform, Donald W. Dryley

Theses and Dissertations

The purpose of this study was test the influence of phase on the quality of speech reproduced by a speaker dependent compression system. The tests consisted of compressing frequency domain speech vectors using the Karhunen-Loeve Transform, with and without phase, then making subjective judgements as to the reproduced quality. Error Metrics were then tested for their suitability as predictors of reproduced quality. The compression software transformed each speech vector into a vector of complex Fourier coefficients (only half of the coefficients are needed as transform is hermitian). Phase was preserved by using the real frequency components to form one vector …

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Identification Of Significant Outliers In Time Series Data, Keri L. Robinson Mar 1993

Identification Of Significant Outliers In Time Series Data, Keri L. Robinson

Theses and Dissertations

This thesis examines the feasibility of using least median of squares (LMS) procedure applied to a reweighted least squares (RLS) autoregression model to identify significant outliers in time series data. The time series were analyzed for data points that were outliers. In order to perform detailed analysis on an outlier. the analyst must be able to determine that an outlier data point is significantly different from normally distributed data. This thesis examines a new method for identifying these outliers. Data from the field were characterized and fit with time series models using an autoregressive reweighted least squares routine (ARRLS) derived …

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Characterization Of Laboratory Generated Turbulence By Optical Phase Measurements, Eric P. Magee Mar 1993

Characterization Of Laboratory Generated Turbulence By Optical Phase Measurements, Eric P. Magee

Theses and Dissertations

The resolution achieved by an optical imaging system in the presence of the random effects of the atmosphere is severely degraded from the theoretical diffraction limit. Techniques exist for recovering near diffraction limited performance of an imaging system in the presence of atmospheric turbulence. As opposed to laboratory testing, testing image enhancement techniques in the Earth's atmosphere imposes many limitations. Unfavorable weather conditions could result in the loss of time and money invested in conducting the experiments. With a properly characterized turbulence generator, with statistics that match those of the atmosphere, experimental testing of image enhancement techniques can be conducted …

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Construction And Testing Of A Neutron And Gamma Spectrometry System Using Pulse Shape Discrimination With An Organic Scintillator, Robert S. Pope Mar 1993

Construction And Testing Of A Neutron And Gamma Spectrometry System Using Pulse Shape Discrimination With An Organic Scintillator, Robert S. Pope

Theses and Dissertations

The goal of this thesis was to construct and test a neutron detector to measure the energy spectrum of 1 to 14-MeV neutrons in the presence of gammas. A spectrometer based on the process of pulse shape discrimination (PSD) was constructed, in which the scintillator NE-213 was used. The primary neutron/ gamma sources used were 78-mCi and 4.7-Ci 239PuBe sources, while 4.7-µCi and 97.6-µCi 22Na gamma sources were used for energy calibration and additional testing of the detector. Proton recoil spectra and Compton electron spectra were unfolded with the neutron and gamma unfolding code FORIST to generate the …

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Rendering The Out-The-Window View For The Afit Virtual Cockpit, W. Dean Mccarty Mar 1993

Rendering The Out-The-Window View For The Afit Virtual Cockpit, W. Dean Mccarty

Theses and Dissertations

The Air Force Institute of Technology (AFIT) is developing a distributed interactive flight simulator, the Virtual Cockpit, using commercial graphics workstations and helmet mounted displays. The Virtual Cockpit communicates with other simulators via local and long-haul networks using the SIMNET protocol. The work reported in this thesis focuses on developing the terrain database for the synthetic environment and on rendering the pilot's view of the database. There are many different file formats for describing 3- dimensional geometric polygonal objects. An analysis of three formats, AFIT GEOM, the Naval Postgraduate School (NPS) DRP, and Software Systems' Flight, is presented. Each file …

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An Analysis Of The Generalized Lambda Distribution, Robert J. Bergevin Mar 1993

An Analysis Of The Generalized Lambda Distribution, Robert J. Bergevin

Theses and Dissertations

The Generalized Lambda Distribution (GLD) is a four parameter function that is capable of mimicking the behavior of a wide range of probability density functions (pdfs). Unfortunately, the GLD presently cannot model every possible type of pdf. Since the reasons for this limitation are unknown, this thesis examines several potential problems in an attempt to expand the range of distributions the GLD can mimic. We first present a discussion of the behavior of the algorithm that is used to search for the appropriate GLD parameter values. In particular, we examine the effect of using an unconstrained search to find the …

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A New Goodness-Of-Fit Test For The Weibull Distribution Based On Spacings, Mark C. Coppa Mar 1993

A New Goodness-Of-Fit Test For The Weibull Distribution Based On Spacings, Mark C. Coppa

Theses and Dissertations

The critical values for a new goodness-of-fit test based on spacings are generated for the Weibull distribution when the shape parameter is known. The critical values are used for testing whether a set of observations follow a Weibull distribution when the scale and location parameters are unknown. A Monte Carlo simulation with 10,000 iterations is used to generate the critical values for sample sizes 5(5)35 at shape parameters k equal to 0.5(0.5)1.5 and for sample sizes 5(5)20 at shape parameters k = 2.0(1.0)4.0. A Monte Carlo power study of the Z* test statistic using 5000 iterations is accomplished using nine …

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