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1999

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Transforming Cobol Legacy Software To A Generic Imperative Model, Dina L. Moraes Mar 1999

Transforming Cobol Legacy Software To A Generic Imperative Model, Dina L. Moraes

Theses and Dissertations

Legacy COBOL code presents challenges for organizations wishing to increase their effectiveness and improve their efficiency. The systems that utilize this code are vital to enterprise operations, yet maintenance of code is expensive. This research presents an alternative that overcomes some of the problems of legacy COBOL code through the use of software reengineering techniques. This research develops a transformation system to convert COBOL code into a generic imperative model, recapturing the initial design and deciphering the requirements implemented by the legacy code, thereby making possible the documentation of legacy systems, design restructuring, and the re-design of a new, enhanced …

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A Structured Approach To Software Tool Integration, Penelope A. Noe Mar 1999

A Structured Approach To Software Tool Integration, Penelope A. Noe

Theses and Dissertations

As the trend towards commercial off-the-shelf (COTS) software continues, civilian companies and government agencies alike are battling with the challenge of making multiple software packages and applications work together. Many of these companies and agencies have attempted to integrate the software tools to form a coherent system that satisfies their goals, often without the use of a step by step approach guiding the effort. Many researchers in the field of software tool integration have determined the areas that need to be addressed when tools are integrated. Some researchers have developed and expanded upon a theoretical model for integration. This model …

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Incorporating Scene Mosaics As Visual Indexes Into Uav Video Imagery Databases, Timothy I. Page Mar 1999

Incorporating Scene Mosaics As Visual Indexes Into Uav Video Imagery Databases, Timothy I. Page

Theses and Dissertations

The rise of large digital video archives has strengthened the need for more efficient ways of indexing video files an accessing the information contained in them. Reconnaissance platforms, such as the Predator UAV, are contributing thousands of hours of video footage that require analysis, storage, and retrieval. A process is proposed for converting a video stream into a series of mosaic and selected still images that provide complete coverage of the original video. The video mosaic images can be utilized as visual indexes into a video database. In addition, mosaic images contain information from an entire sequence of video frames …

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Generating Executable Code From Formal Specifications Of Primitive Objects, Travis W. Tankersley Mar 1999

Generating Executable Code From Formal Specifications Of Primitive Objects, Travis W. Tankersley

Theses and Dissertations

The concept of developing a model for producing compilable and executable code from formal software specifications has long been a goal of software engineers. Previous research at the Air Force Institute of Technology (AFIT) has been focused on specification and domain analysis. An analysis model is populated using specifications written in Z. Then, a set of preliminary design transforms refines the specification in the analysis model. This research bridges the gap between analysis and design, allowing source code to be produced from formal specifications of primitive objects using transformational programming. The contribution of this thesis is to transform the analysis …

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A Refinement And Cross-Validation Of The Special Sensor Microwave Imager (Ssm/I) Calibration-Validation (Cv) Brightness Temperature Algorithm, Mark R. Adair Mar 1999

A Refinement And Cross-Validation Of The Special Sensor Microwave Imager (Ssm/I) Calibration-Validation (Cv) Brightness Temperature Algorithm, Mark R. Adair

Theses and Dissertations

The Air Force Weather Agency (AFWA) currently uses an algorithm to calculate surface temperatures from microwave observations taken by the Special Sensor Microwave Imager (SSM/I) aboard the orbiting platforms of the Defense Meteorological Satellite Program (DMSP). This algorithm, called the Calibration-Validation (CV) algorithm, used multiple linear regression to calculate coefficients relating microwave brightness temperatures and land surface temperatures. Because the coefficients in this algorithm do not take into account the identity of the individual satellite, the question arose whether this assumption was valid. This thesis used multiple linear regression, stepwise linear regression, and qualitative regression on 3700 data sets from …

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A Comparison Of Horizontal Cloud-To-Ground Lightning Flash Distance Using Weather Surveillance Radar And The Distance Between Successive Flashes Method, Christopher C. Cox Mar 1999

A Comparison Of Horizontal Cloud-To-Ground Lightning Flash Distance Using Weather Surveillance Radar And The Distance Between Successive Flashes Method, Christopher C. Cox

Theses and Dissertations

On April 29th, 1996 an airman servicing a C-130 aircraft on Huriburt AFB Florida was struck and killed by a lightning flash that traveled an estimated 7 to 10 miles from storms south of the airfield. Ten other workers were injured in the incident. The fatal flash occurred just 8 minutes after the base weather station allowed a lightning advisory to expire. The incident brought to question the adequacy of lightning advisory criteria. Very little research has been done on the horizontal distance that cloud-to-ground lightning flashes occurs from the center of a thunderstorm. This thesis used the WSR-88D method, …

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Improving Cape Canaveral's Next-Day Thunderstorm Forecasting Using A Meso-Eta Model-Based Index, John C. Crane Mar 1999

Improving Cape Canaveral's Next-Day Thunderstorm Forecasting Using A Meso-Eta Model-Based Index, John C. Crane

Theses and Dissertations

Reliable thunderstorm forecasts are essential to safety and resource protection at Cape Canaveral. Current methods of forecasting day-2 thunderstorms provide little improvement over forecasting by persistence alone and are therefore in need of replacement. This research focused on using the mesoscale eta model to develop an index for improved forecasting of day-2 thunderstorms. Logistic regression techniques were used to regress the occurrence of a thunderstorm at Cape Canaveral against day-2 forecast variables output, or derived, from the mesoscale eta model. Accuracy and bias scores were calculated for the forecasts made by the regression equations, and the forecast results were compared …

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Evaluation Of Barnes' Method And Kriging For Estimating The Low Level Wind Field, Michael W. Engel Mar 1999

Evaluation Of Barnes' Method And Kriging For Estimating The Low Level Wind Field, Michael W. Engel

Theses and Dissertations

This thesis evaluates two different methods of estimating a three dimensional wind field based upon a limited number of irregularly-spaced observations. This work was performed for the 45th Weather Squadron to determine how well the two methods worked and their potential for use in a visualization program. The two methods evaluated were Barnes' method and a method called Kriging, which is commonly used in geostatistics. Both of these estimation techniques were implemented and then evaluated to determine how accurate the estimates were that they created. The methods' accuracies were determined by withholding an observation from the observed wind field data …

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An Improved Thunderstorm Forecast Index For Cape Canaveral, Florida, James A. Everitt Mar 1999

An Improved Thunderstorm Forecast Index For Cape Canaveral, Florida, James A. Everitt

Theses and Dissertations

This thesis creates a new algorithm to replace the Neumann-Pfeffer Thunderstorm Index (NPTI). The 45th Weather Squadron at Patrick AFB, Florida, uses the NPTI as an objective means of determining the probability of thunderstorm occurrence at Cape Canaveral. The probability is used for mission planning and resource protection, and increasing the accuracy of NPTI can potentially save billions of dollars for the United States space program. Stratified logistical regressions are performed and probability equations are derived for May through September using upper air data and surface observations for Cape Canaveral. A logistical regression of NPTI was also performed. Variables include …

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A Validation Study Of Cloud Scene Simulation Model Temporal Performance, Glenn Kerr Mar 1999

A Validation Study Of Cloud Scene Simulation Model Temporal Performance, Glenn Kerr

Theses and Dissertations

Cloud Scene Simulation Model (CSSM) temporal performance was validated by comparing the cloud forcing signatures on observed radiometric time series with those derived from CSSM output for initial conditions similar to that for the observed data. Observed radiometric data was collected by a normal incidence pyraheliometer sensitive to wavelengths in the range .3mm to 3mm. Simulation radiometric time series data was derived by applying the following process to each case study. CSSM cloud liquid water content (CLWC) grids were converted to grids of slant path optical depth values by the Fast Map post processor to the CSSM. A ray tracing …

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Forecasting Downdraft Wind Speeds Associated With Airmass Thunderstorms For Peterson Air Force Base, Colorado, Using The Wsr-88d, Travis A. Steen Mar 1999

Forecasting Downdraft Wind Speeds Associated With Airmass Thunderstorms For Peterson Air Force Base, Colorado, Using The Wsr-88d, Travis A. Steen

Theses and Dissertations

During the period Jun-Aug 96, four Air Force installations suffered over $4.8 million in damage from convective winds. During the same summer, Air Force Space Command units issued nearly 65% of their weather warnings for convective winds, making the forecasting of convective winds the most frequent challenge to forecasters. This thesis seeks to assist Air Force forecasters at Peterson Air Force Base (PAFB), Colorado, in forecasting airmass thunderstorm downdraft wind speeds using the Weather Surveillance Radar-1988 Doppler (WSR-88D). To accomplish this purpose, several existing potential downdraft wind speed prediction techniques were evaluated against the observed wind speeds of nineteen airmass …

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Predicting Launch Pad Winds At The Kennedy Space Center With A Neural Network Model, Steven J. Storch Mar 1999

Predicting Launch Pad Winds At The Kennedy Space Center With A Neural Network Model, Steven J. Storch

Theses and Dissertations

This thesis uses neural networks to forecast winds at the Kennedy Space Center and the Cape Canaveral Air Station launch pads. Variables are developed from WINDS tower observations, surface and buoy observations, and an upper-air sounding. From these variables, a smaller set of predictive inputs is chosen using a signal-to-noise variable screening method. A neural network is then trained to forecast launch pad winds from the inputs. The network forecasts are compared to persistence, and peak wind predictions are found skillful compared to persistence. An ensemble modeling technique using Toth's and Kalnay's breeding of growing modes method is explored with …

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Using The Wsr-88d To Forecast Downburst Winds At Cape Canaveral Air Station And The Kennedy Space Center (Ccas/Ksc), Gerald D. Sullivan Jr. Mar 1999

Using The Wsr-88d To Forecast Downburst Winds At Cape Canaveral Air Station And The Kennedy Space Center (Ccas/Ksc), Gerald D. Sullivan Jr.

Theses and Dissertations

The 45 Weather Squadron is tasked with providing several convective wind warnings in support of the U. S. Space Program. The forecasters use a radar-based forecast technique to determine if a thunderstorm has the potential to produce a gust that meets warning criteria. This technique, the Echo Top/Vertically Integrated Liquid Wind Gust Potential (ET/VIL WGP), has not previously been evaluated for use in the Cape Canaveral Air Station and Kennedy Space Center (CCAS/KSC) locale. Additionally, there are two other radar-based forecast techniques that required evaluation for possible inclusion into the 45 WS forecast process. These are the Maximum Reflectivity / …

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An Improved Asynchronous Implementation Of A Fast Fourier Transform Architecture For Space Applications, David J. Barnhart Mar 1999

An Improved Asynchronous Implementation Of A Fast Fourier Transform Architecture For Space Applications, David J. Barnhart

Theses and Dissertations

A second-generation fully asynchronous Fast Fourier Transform (FFT) processor for space applications is developed in this thesis. A high-performance patented FFT architecture invented by Suter and Stevens was used as the basis for a 16-point FFT (FFT-16) processor design. A brief derivation of the architecture, the asynchronous design methodologies used and space-based integrated circuit issues are presented. The Synopsys VLSI CAD system and a radiation tolerant design library developed by the Air Force Research Laboratory were used to implement the design. A critical building block of the FFT-16, the FFT-4, was fabricated as a cost-effective method to validate the cell …

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Asymmetric Load Balancing On A Heterogeneous Cluster Of Pcs, Christopher A. Bohn Mar 1999

Asymmetric Load Balancing On A Heterogeneous Cluster Of Pcs, Christopher A. Bohn

Theses and Dissertations

In recent years, high performance computing with commodity clusters of personal computers has become an active area of research. Many organizations build them because they need the computational speedup provided by parallel processing but cannot afford to purchase a supercomputer. With commercial supercomputers and homogenous clusters of PCs, applications that can be statically load balanced are done so by assigning equal tasks to each processor. With heterogeneous clusters, the system designers have the option of quickly adding newer hardware that is more powerful than the existing hardware. When this is done, the assignment of equal tasks to each processor results …

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An Efficient Gps Position Determination Algorithm, Carlos R. Colon Mar 1999

An Efficient Gps Position Determination Algorithm, Carlos R. Colon

Theses and Dissertations

The use of detect, or closed-form solutions of the trilateration equations used to obtain the position fix in GPS receivers is investigated. The paper is concerned with the development of an efficient new position determination algorithm that uses the closed-form solution of the trilateration equations and works in the presence of pseudorange measurement noise and for an arbitrary number of satellites. in addition, an initial position guess is not required and good estimation performance is achieved even under high GDOP conditions. A two step GPS position determination algorithm which 1) entails the solution of a linear regression problem and, 2) …

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Te Scattering From Bubbles In Ram, John G. Cochran Mar 1999

Te Scattering From Bubbles In Ram, John G. Cochran

Theses and Dissertations

This research looks at various bubble sizes in one particular magnetic RAM (MAURAM) type, from grazing incidence (00) to 450 and at a frequency range from 2-18 GHz, TE polarization. The results from the absolute RCS measurement of the various sized RAM bubbles are discussed in terms of a frequency dependent increase in RCS. In the frequency band of interest, 2-18GHz, a RAM bubble increases the RCS at all angles, from grazing incidence (00) to 450. From 10-18GHz the RAM bubble does not cause an increase in RCS. In general the highest RCS is at 2GHz and tapers down as …

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An Empirical Prediction Model Of The Performance Impacts Of Material Tolerances In Frequency Selective Surfaces Using The Monte Carlo Method, Matthew D. Craig Mar 1999

An Empirical Prediction Model Of The Performance Impacts Of Material Tolerances In Frequency Selective Surfaces Using The Monte Carlo Method, Matthew D. Craig

Theses and Dissertations

Standard computational tools predicting frequency selective surface (FSS) performance model periodic structures as an infinite-by-infinite array of perfectly placed elements with perfect, identical dimensions, and with dielectric layers of uniform thickness and material composition. These models do not address perturbations caused by manufacturing tolerances of elements and dielectric layers, nor do they address edge effects caused by finite-by-finite dimensional arrays. The Monte Carlo Method was used to determine the effects of random variations in element dimension, placement, dielectric thickness, and dielectric material on FSS performance. A full-factorial experimental design was applied, and eight hundred twenty-five unique finite arrays of elements …

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Trade-Off Analysis Of Communications Capabilities Of Inter-Satellite Links, Andrew J. Feltman Mar 1999

Trade-Off Analysis Of Communications Capabilities Of Inter-Satellite Links, Andrew J. Feltman

Theses and Dissertations

This thesis designs, develops, and uses software Graphical User Interfaces (GUIs) to analyze the communications capabilities of Radio Frequency (RF) Inter-Satellite Links (ISLs). The GUIs are geared towards analyzing the proposed ISLs of the Discoverer II program, but are general enough to permit analysis of any free-space RF ISLs. Discoverer II is a demonstration program of low-earth orbiting satellites and is primarily focused on satellite-based sensor technology. This thesis shows RF ISLs can meet the program requirement to broadcast the sensor data back to CONUS in near-real-time. The GUIs operate in real-time and explore trade-offs in the communications capability by …

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Computation Of Scattering From Bodies Of Revolution Using An Entire-Domain Basis Implementation Of The Moment Method, Arthur P. Ford Iv Mar 1999

Computation Of Scattering From Bodies Of Revolution Using An Entire-Domain Basis Implementation Of The Moment Method, Arthur P. Ford Iv

Theses and Dissertations

Research into improved calibration targets for measurement of radar cross-section has created a need for the ability to accurately compute the scattering from perfectly conducting bodies of revolution. Common computational techniques use Moment Method codes that employ subdomain basis functions to expand the unknown current density. This approach has its shortcomings. Large numbers of basis functions are required, and increasing the number of basis functions to improve accuracy after an initial computation requires re-computation of previous results and lost processing time. This research involves using basis functions that have as their domain the entire length of the surface. Entire-domain basis …

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Non Co-Operative Detection Of Lpi/Lpd Signals Via Cyclic Spectral Analysis, Andrew M. Gillman Mar 1999

Non Co-Operative Detection Of Lpi/Lpd Signals Via Cyclic Spectral Analysis, Andrew M. Gillman

Theses and Dissertations

This research proposes and evaluates a novel technique for detecting LPI/LPD communication signals using a digital receiver primarily designed to detect radar signals, such as a Radar Warning Receiver (RWR) or an Electronic Support Measures (ESM) receiver. The proposed Cyclic Spectrum Analysis (CSA) receiver is a robust detector that takes advantage of the spectral correlation properties of second-order cyclostationary signals. A computationally efficient algorithm is used to estimate the Spectral Correlation Function (SCF). Using state-of-the-art FFT processing, it is expected that the proposed CSA receiver architecture could estimate the entire cyclic spectrum m approximately 0.6 ms. The estimate is then …

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Optimal Wavelet Denoising For High Range Resolution Radar Classification, Brian M. Huether Mar 1999

Optimal Wavelet Denoising For High Range Resolution Radar Classification, Brian M. Huether

Theses and Dissertations

Noncooperative identification (NCTI) of airborne targets is a top priority for the Air Force and this thesis makes a significant contribution to that area. High range resolution radar (HRR) provides an attractive means to perform NCTI. When measured HRR data is used, classification performance is excellent. However, it is often not feasible to acquire measured HRR signatures for a wide set of targets, thus necessitating the use of synthetically generated HRR data. Classification performance suffers severe degradation when using synthetic data. This thesis suggests that a large portion of HRR signature content is non-discriminatory and that this content is a …

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Graphical User Interface And Microprocessor Control Enhancement Of A Pseudorandom Code Generator, John M. Kos Mar 1999

Graphical User Interface And Microprocessor Control Enhancement Of A Pseudorandom Code Generator, John M. Kos

Theses and Dissertations

Modern digital communication techniques often require the generation of pseudorandom numbers or sequences. The ability to quickly and easily produce various codes such as maximal length codes, Gold codes, Jet Propulsion Laboratory ranging codes, syncopated codes, and non-linear codes in a laboratory environment is essential. This thesis addresses the issue of providing automated computer control to previously built, manually controlled hardware incorporating the Stanford Telecom STEL-1032 Pseudo-Random Number (PRN) Coder. By incorporating a microcontroller into existing hardware, the STEL-1032 can now be conveniently controlled from a MATLAB Graphical User Interface (GUI). The user can quickly create, save, and recall various …

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Terrain Backscattering Coefficient Generator, Ricardo Mediavilla Mar 1999

Terrain Backscattering Coefficient Generator, Ricardo Mediavilla

Theses and Dissertations

Using already available data, a backscattering coefficient generator (BCG) for several types of terrain and measurement conditions is developed. The types of terrain are: (1) soils and rocks, (2) trees, (3) grasses, (4) shrubs, (5) short vegetation, (6) roads, (7) urban areas, (8) dry snow, and (9) wet snow. These data sets typically cover incidence angles ranging between 0 and 80 degrees where 0 is normal to the terrain. Measurement conditions are defined by: (1) incidence angle, (2) wave polarizations configuration (HH, HV, or VV), and (3) radar band (L, C, S, X, Ku, Ka, or W). The BCG output …

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The Effect Of Registration Errors On Tracking In A Networked Radar System, Bradley J. Mortenson Mar 1999

The Effect Of Registration Errors On Tracking In A Networked Radar System, Bradley J. Mortenson

Theses and Dissertations

To successfully combine information from distributed radar sensors, it is essential that each sensor be correctly referenced in a global coordinate system. If there are biases in the reported position of these sensors, the reported target position will also be biased and the ensuing global estimate of the target position will be degraded. Furthermore, any biases in range or azimuth measurements of these sensors will likewise be reflected in the degradation of global estimate of target position. Registration is the process of ensuring that these errors do not result in the creation of an additional redundant target when only a …

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A Constructive Induction Approach To Computer Immunology, Kelley J. Cardinale, Hugh M. O'Donnell Mar 1999

A Constructive Induction Approach To Computer Immunology, Kelley J. Cardinale, Hugh M. O'Donnell

Theses and Dissertations

With the increasing birth rate of new viruses and the rise in interconnectivity and interoperability among computers, the burden of detecting and destroying computer viruses is severe. This research integrated four domains: computer virus detection, human immunology, computer immunology and an automated form of machine learning called constructive induction. First, a Computer Health System, based on the public health system, was defined to improve the 'global' approach to computer virus protection. Second, a computer immune model, based on the human immune system, was defined to improve the 'local' approach to virus detection. Third, the detection component of this computer immune …

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High-Grade Paper Recycling: A Program Management Perspective, Rodger L. Carter Mar 1999

High-Grade Paper Recycling: A Program Management Perspective, Rodger L. Carter

Theses and Dissertations

Recycling of high-grade paper is one method of reducing the use of natural resources and the amount of waste being emitted into the environment, both in the process of manufacturing and in the disposal of unneeded documents. The Air Force Materiel Command (AFMC) is a significant user of high-grade paper, thus recycling represents a potential saving to society in the form of lessened negative impact on the environment as the result of AFMC operations. The possibility also exists for AFMC to reduce operating costs. The purpose of this study is to explore means of reducing high-grade paper disposal by AFMC, …

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Multi-Discipline Network Vulnerability Assessment, Karilynne Wallace Mar 1999

Multi-Discipline Network Vulnerability Assessment, Karilynne Wallace

Theses and Dissertations

Air Force Space Command has a mission to provide real-time, survivable, and enduring communications, surveillance, environmental monitoring, navigation, and warning....according to Air Force Space Handbook - A War Fighters Guide to Space. In order to prevent disruption of the critical networks in Space Command, a vulnerability assessment must be performed. The set of components called a vulnerability set, which could cause network disruption, must be identified and prioritized. In order to move beyond subjective prioritization, implementation of a quantitative methodology that measures the value of each vulnerability set is needed. This thesis proposes a technique for vulnerability assessment of a …

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Structural Emergence And The Collaborative Behavior Of Autonomous Nano-Satellites, Daniel J. Petrovich Mar 1999

Structural Emergence And The Collaborative Behavior Of Autonomous Nano-Satellites, Daniel J. Petrovich

Theses and Dissertations

The collaborative behavior of nano-satellites in a zero-gravity environment is explored, and satellite characteristics are proposed that maximize constellation robustness and minimize manufacturing costs. Behavioral algorithms are proposed to facilitate both swarming and structural formation and are validated using the Structural Emergence Simulator (STEMS) Graphical User Interface (GUl). A payload of multiple satellites is placed in a zero-gravity environment and released to re-configure autonomously into a pre-designed structure. Data transmission between satellites is not permitted during the swarming phase of the structure formation mission. A binary behavior algorithm is invented that produces a direction and magnitude solution to the satellite …

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A Climatology-Based Model For Long-Term Prediction Of Radar Beam Refraction, Todd S. Pittman Mar 1999

A Climatology-Based Model For Long-Term Prediction Of Radar Beam Refraction, Todd S. Pittman

Theses and Dissertations

The National Air Intelligence Center, WPAFB, OH, needs more accurate predictions of radar beam refraction. A new mode was developed for this thesis replacing the standard atmosphere approach with raytracing and climatology. Usually a microwave radio beam bends towards the earth with a radius of curvature greater than the earth's surface. However, seasonal and climatic variations influence the bending, and at times create temperature or moisture inversions that redirect the energy along the earth's surface leaving radio holes where there is no coverage. This model uses iterative raytracing to determine the most direct path from radar to target through the …

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