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Articles 11191 - 11220 of 11490
Full-Text Articles in Engineering
Life Cycle Costs Of The C-130 Electrical Power System Upgrade, Theodore D. Seymour
Life Cycle Costs Of The C-130 Electrical Power System Upgrade, Theodore D. Seymour
Theses and Dissertations
This research investigated the life cycle costs of three alternative electrical power systems for a planned electrical system upgrade to the C-130 transport aircraft. Research identified the contractors as (1) Sundstrand, (2) Westinghouse, and (3) Leland. The literature review included discussions on the C-130, electrical power systems and the proposed alternatives, and the elements of life cycle cost analysis. In the discussion on supportability issues, this research evaluated changes in mission capable rates and the needed fleet size to perform the current mission. In estimating Operating and Support costs, this research used the analogy approach. Analogies were based on expert …
Efficient Aircrew Scheduling In An Operational Test And Evaluation Organization, Charles P. Modrich
Efficient Aircrew Scheduling In An Operational Test And Evaluation Organization, Charles P. Modrich
Theses and Dissertations
The original intent of this research was to locate or develop tools which would improve the efficiency of the aircrew scheduling process in the 4950 Test Wing. However, late in the research it became apparent that several factors observed by the researcher complicate the implementation of more efficient methods. Therefore, the focus of the research became the documentation of those factors. A case study methodology was used in answering the investigative questions. This was an exploratory study conducted in a field setting environment. Direct observation and the use of structural interviews with scheduling personnel were the methods of data collection. …
An Analysis Of Total Quality Management In Aeronautical Systems Division, Mark D. Caudle
An Analysis Of Total Quality Management In Aeronautical Systems Division, Mark D. Caudle
Theses and Dissertations
This study investigated the major schools of thought on various aspects of quality management and quality improvement. Areas covered included definitions of waste and quality, views on the cost of quality, tools and techniques used for quality improvement, and management philosophies and frameworks for continuous improvement. In addition, this study analyzed the structure and training content of the current Total Quality Management program at Aeronautical Systems Division (ASD). Pre- and post-test surveys on employee attitudes toward organizational effective were analyzed from the Advanced Cruise Missile System Program Office (SPO), the F-15 SPO, and the ASD Deputy Chief of Staff for …
Model Identification And Control System Design For The Lambda Unmanned Research Vehicle, Gerald A. Swift
Model Identification And Control System Design For The Lambda Unmanned Research Vehicle, Gerald A. Swift
Theses and Dissertations
Research for this thesis centered on the Lambda Unmanned Research Vehicle (URV), an asset of the Flight Dynamics Directorate, Wright Laboratory Patterson AFB. The following tasks were accomplished: (1) a linear, state-space, small perturbation model was developed for both the longitudinal and lateral directional dynamics of the vehicles, and (2) pitch rate roll rate, and yaw rate flight controllers were designed using classical and multivariable feedback methods. The parameters of the linear, state space, small perturbation model were estimated from actual flight test data. Digital Datcom was first used to estimate stability and control derivatives from the vehicle's geometry. Maximum …
A Microcomputer Program For Estimating Production Costs Of Injection Molded Plastic Structures, Kyle F. Byard
A Microcomputer Program For Estimating Production Costs Of Injection Molded Plastic Structures, Kyle F. Byard
Theses and Dissertations
The job of estimating the production costs of injection molded thermoplastic structures requires designers and analysts to produce detailed preliminary drawings and consult machinists with expertise in mold production. Interviews with injection molding experts produced a scale of part complexity and associated range of labor hours for mold production. This scale is incorporated into a cost estimating methodology which allows the analyst to estimate the cost of the structure without the aid of technicians. The resulting cost model for the injection molding process is then programmed into an interactive Pascal computer program for ease of use and documentation.
Higher-Order Thickness Expansions For Cylindrical Shells, Randy A. Smith
Higher-Order Thickness Expansions For Cylindrical Shells, Randy A. Smith
Theses and Dissertations
Eight variations of higher-order transverse shear deformation (HTSD) theory were developed for composite shells. Three attributes were varied to produce the eight variations. These attributes include the order of the thickness expansions used to approximate the shell shape factors and the assumed linear displacement field and the nonlinearity of transverse shear strain. Several cylindrical shell problems were investigated using SHELL, a finite- element code with a 36 degree of freedom cylindrical shell element. MACSYMA, a symbolic manipulation code, was used to formulate the element independent stiffness arrays for each variation of the theory. When all nonlinear strain- displacement terms for …
An Analysis Of Base Level Environmental Organizations, John F. Akers Jr.
An Analysis Of Base Level Environmental Organizations, John F. Akers Jr.
Theses and Dissertations
The purpose of this thesis was to try and determine if there was one type of environmental organization which was truly so much more effective than the others that all bases should have it, or if the decision of which type of environmental organization to have should be left entirely to the bases. In addition, I hoped to discover the advantages and disadvantages of each type of organizational structure. I feel that knowing these advantages and disadvantages will greatly aid those individuals making the decisions on environmental organizational structure. In completing this study I turned to the only place the …
The Operation Of Military Family Housing As A Business Enterprise. A Case Study At Langley Air Force Base, Virginia, Michael T. Ray
The Operation Of Military Family Housing As A Business Enterprise. A Case Study At Langley Air Force Base, Virginia, Michael T. Ray
Theses and Dissertations
The focus of this research was to determine the feasibility of operating Military Family Housing (MFH) as a business enterprise, based on rental income. A case study of the Langley AFB Military Family Housing operation during FY 90 was used to determine if housing allowances forfeited by residents of base housing would provide sufficient rental income for the annual operations, maintenance and capital improvement of the MFH assets. It further compared the descriptive data from Langley AFB, Virginia, to USAF averages to determine if the findings at Langley were generalizable across the Air Force. The case study showed that Basic …
Evaluation Of Managerial Challenges Created By Acceleration Of The Installation Restoration Program, Robert L. Vinson Iii
Evaluation Of Managerial Challenges Created By Acceleration Of The Installation Restoration Program, Robert L. Vinson Iii
Theses and Dissertations
This study investigates the distribution of managerial tasks related to the Installation Restoration Program (IRP). Initiated in 1986, the IRP is the DoD program to identify and clean-up hazardous waste sites. Study areas include current distribution of managerial tasks, changes in task distribution needed to accelerate the program, and potential resource constraints. Additionally, the study considers how acceleration of Army and Navy restoration programs could impact the Air Force IRP. The study reveals IRP management is heavily centralized at MAJCOM with most technical work being performed through contracts with service centers. Individual bases have little direct involvement in the program. …
Industrial Wastewater Management Practices In Air Force Logistics Command, Patrick J. Smith
Industrial Wastewater Management Practices In Air Force Logistics Command, Patrick J. Smith
Theses and Dissertations
The selection of a model plant was based upon criteria established by a review of current literature. The criteria were permit compliance, plant performance, and the adoption of pollution prevention as a corporate environmental philosophy. In this study, private sector firms were examined to identify the best industrial wastewater management practices using a Total Quality Management (TQM) tool called benchmarking. The data gathering process consisted a survey of water pollution control organizations, and a survey of benchmark candidates. The purpose of surveying water pollution control organizations was to objectively identify possible benchmark candidates. A questionnaire was then used to gather …
Applying The Theory Of Constraints To A Base Civil Engineering Operations Branch, Bryan K. Zachmeier
Applying The Theory Of Constraints To A Base Civil Engineering Operations Branch, Bryan K. Zachmeier
Theses and Dissertations
The purpose of this thesis is to introduce the Civil Engineering manager to the Theory of Constraints management philosophy and to show how to apply this process of ongoing improvement to the Operations Branch. One of the reasons for the success of Theory of Constraints in commercial firms is that it provides all levels of management the ability to find simple solutions for bridging the gap between local and global issues. This 'bridge' is built by clearly defining the goal of the organization and using performance measurements capable of predicting the effect of local decisions and actions on the goal. …
A Comparative Analysis Of Three Water Treatment Programs For Cooling Tower Systems, Jeffry W. Shea
A Comparative Analysis Of Three Water Treatment Programs For Cooling Tower Systems, Jeffry W. Shea
Theses and Dissertations
This study investigated the cost and effectiveness of three cooling tower water treatment programs. The programs studied were an acid program developed at WPAFB, a commercial solubilizer program manufactured by Lombardi, Inc, and a crystal modifier program developed by Dias, Inc. The experiment ran for 60 days at which time cost and effectiveness data were collected. Cost comparison was evaluated on the basis of tower performance in MBtu. The costs considered in this experiment were water costs, sewer costs, and chemical costs. All costs were recorded and totaled, then divided by the tower's performance. The effectiveness of each treatment method …
Impacts Of Biomonitoring Requirements On Dod Wastewater Treatment Facilities, James R. Brady
Impacts Of Biomonitoring Requirements On Dod Wastewater Treatment Facilities, James R. Brady
Theses and Dissertations
Legislative emphasis on reducing the toxicity of wastewater effluent has resulted in increasingly sophisticated methods of determining toxicity. The purpose of this research project is to assess the impacts on DoD wastewater treatment facilities of one new monitoring method, biomonitoring. Biomonitoring has impacted DoD wastewater treatment facilities, however not to the degree anticipated. For bases that have been impacted, cost of contracting the tests is the primary problem associated with biomonitoring. Many bases have not been impacted because wastewater reuse has negated the need for discharge permits, and the inherent monitoring requirements. Bases subject to biomonitoring should assess water reuse …
An Expert System Solution For The Quantitative Condition Assessment Of Electrical Distribution Systems In The United States Air Force, David O. Paine
An Expert System Solution For The Quantitative Condition Assessment Of Electrical Distribution Systems In The United States Air Force, David O. Paine
Theses and Dissertations
Faced with a rapidly decreasing budget, the Air Force is in need of a method to objectively evaluate its aging utility infrastructure assets. This objective evaluation could be used to compare similar facility infrastructure systems for identification of possible problem areas and prioritization of major repair projects. This thesis developed a component model which can be used to objectively evaluate a typical electrical distribution system. The Delphi process was used to gather expert opinions regarding three areas: (1) the critical components which should be included in the model, (2) the relative importance of each selected critical component, and (3) the …
Investigation Of Advanced Aircraft Performance Measures Of Merit Including New Agility Metrics, Bruce A. Fox
Investigation Of Advanced Aircraft Performance Measures Of Merit Including New Agility Metrics, Bruce A. Fox
Theses and Dissertations
Advanced aircraft performance measures of merit have been proposed and individually analyzed by various researchers. These metrics have been consolidated into a single computer code as part of this research effort. This code was used to study the relationships between the advanced metrics, aircraft design metrics and an aircraft's trajectory performance. The study found a linear relationship existed between the advanced metrics and the design metrics. This relationship was used to quantify the required levels of the advanced metrics which would give desired changes in trajectory performance. The results showed that advanced metrics could be applied only to very specific …
Analysis Of Department Of Defense Organic Depot Maintenance Capacity Management And Facility Utilization Factors, Marlies Dewoody
Analysis Of Department Of Defense Organic Depot Maintenance Capacity Management And Facility Utilization Factors, Marlies Dewoody
Theses and Dissertations
This study investigated the effects of mandated depot capacity utilization rates on throughput, inventory, and operating expense. The measures of merit analyzed were work in process inventories, leadtime, and throughput. Since the services do not use a common computer system to track/compute capacity data, a computer simulation provided the data used to meet the research objectives. The simulation modeled a serially interdependent system subject to statistical fluctuations. Variability in the system was reduced by reducing the spread around the processing time mean. Buffer inventories were placed in front of each process to protect the process from variability. Constrained systems were …
Determining Production Capability In Aircraft Maintenance: A Regression Analysis, Charles R. Jung
Determining Production Capability In Aircraft Maintenance: A Regression Analysis, Charles R. Jung
Theses and Dissertations
This research analyzed twenty-three maintenance constraint and three production output performance measures for nine SAC aircraft systems. SAS System for Elementary Statistical Analysis is used to analyze twenty-one months of ex post facto maintenance data. Correlation analysis is used to identify maintenance constraints that assist in explaining aircraft maintenance production capability. Forward stepwise regression is used to build predictive models of maintenance production capability for each of the nine aircraft systems. The twenty-three maintenance constraint measures are regressed against three productivity output measures: Mission Capable Rate, Total Not Mission Capable Supply Rate and Total Not Mission Capable Maintenance Rate. The …
An Analysis Of Measures Used To Evaluate The Air Force Critical Item Program, Robert R. Lee
An Analysis Of Measures Used To Evaluate The Air Force Critical Item Program, Robert R. Lee
Theses and Dissertations
The purpose of this study was to evaluate the potential of two measures, percent defects and cycle time, to measure the overall performance of the Air Force Critical Item Program (CIP). The need for such study was generated from the current absence of any measurement system available to evaluate the CIP. This research used these two measures with actual data, evaluated the correlation between aircraft availability and percent defects and cycle time, and analyzed management perceptions addressing the usefulness of these measures for field use. Performance of this analysis resulted in support for these measures by over two thirds of …
The Effect Of Defense Management Review Decision 904, Stock Funding Depot Level Reparables, On Cash Flow Within The Reparable Support Division Of The Air Force Stock Fund, Deborah A. Elliot
The Effect Of Defense Management Review Decision 904, Stock Funding Depot Level Reparables, On Cash Flow Within The Reparable Support Division Of The Air Force Stock Fund, Deborah A. Elliot
Theses and Dissertations
This study investigated what the potential cash flow condition of the Reparable Support Division of the Air Force Stock Fund might be after final implementation of the procedures outlined in Defense Management Review Decision 904, Stock Funding Depot Level Reparables. The operation of the future Reparable Support Division was modelled using the General Purpose Simulation Software (GPSS/H) package and future cash flow conditions were projected through use of this model. Recommendations were then made based on the results of these projections and based on other data gathered during the course of the research process.
High Frequency Scattering Code In A Distributed Processing Environment, Scott Suhr
High Frequency Scattering Code In A Distributed Processing Environment, Scott Suhr
Theses and Dissertations
Government agencies and academic institutions are very interested programming for concurrent processing to cut computer processing time. However, many of the world's problems have already been coded for conventional serial computers. This research demonstrates the feasibility of modifying existing serial codes for execution in a concurrent processing environment. A electromagnetic scattering prediction code known as NECBSC is incrementally modified to incorporated various levels of concurrent computing. The data processed by the code are completely independent, providing an avenue for data decomposition of the process. Portions of the data set are processed on each mode and the results combined for final …
Investigation Of Adaptive Controllers For Puma Trajectory Tracking, Daniel J. Sims
Investigation Of Adaptive Controllers For Puma Trajectory Tracking, Daniel J. Sims
Theses and Dissertations
Two robust model-based controllers and two decentralized adaptive controllers are experimentally evaluated. Algorithm evaluation is motivated by the need for controllers with good high speed tracking under varying payload conditions. The test case is a PUMA-560 robotic manipulator operating over the standard test suite. The model-based controllers are made robust by the addition of either an auxiliary input term or an adaptive feedforward compensator based on Lyapunov Theory. The model-based auxiliary input controller (MBAIC) adapts the gain matrices used in computing an additional torque to be combined with model-based feedforward and PD feedback torques. The adaptive model-based controllers adapt the …
A Multiple Model Adaptive Estimator Using First And Second-Order Acceleration Models For Use In A Forward-Looking Infrared Tracker, Barbara J. Niblett
A Multiple Model Adaptive Estimator Using First And Second-Order Acceleration Models For Use In A Forward-Looking Infrared Tracker, Barbara J. Niblett
Theses and Dissertations
The performance of a multiple model adaptive estimator (MMAE) for an enhanced correlator/forward-looking-infrared tracker for airborne targets is analyzed in order to improve its performance. Performance evaluation is based on elemental filter selection and MMAE estimation error sizes and trends. The elemental filters are based on either first or second-order acceleration models. Improved filter selection is achieved by using acceleration models that separate the frequency content of acceleration power spectral densities into non- overlapping regions with second-order models versus the more traditional overlapping regions with first-order models. A revised tuning method is presented. The maximum a posteriori (MAP) versus the …
An Alternative Algorithm For Discrete-Time Filtering, Frederick H. Zeitz Iii
An Alternative Algorithm For Discrete-Time Filtering, Frederick H. Zeitz Iii
Theses and Dissertations
The discrete-time Kalman filter is a conditional mean estimator of the states of a linear stochastic process, conditioned on the previous state and current measurements. It assumes that the states and noise inputs can be represented as jointly Gaussian random variables. The influence diagram is a decision analysis tool. Under certain conditions, it can represent continuous, jointly Gaussian random variables. The conditioning order of the random variables may be changed (using Bayes' rule) so that any random variable can be conditioned on any other subset of random variables in the diagram. Under these conditions, an influence diagram can represent the …
Development Of A Personal Computer Simulation Program Of The Ln-94 Inertial Navigation System, Thomas E. Flynn
Development Of A Personal Computer Simulation Program Of The Ln-94 Inertial Navigation System, Thomas E. Flynn
Theses and Dissertations
This thesis develops a simulation that emulates a Litton LN-94 INS. Real time simulation is achieved for a stationary navigation case and a straight-and-level flight trajectory are provided to exercise the simulation dynamics. The user interface is simple and requires little previous knowledge to operate. The communication link with the MILSTD 1553B bus provide a realistic environment in which to collect and analyze data. The simulation is processed on an 80386 IBM compatible personal computer. A 23-state INS error model is implemented and integration is performed by a fifth-order Kutta-Merson routine. The simulation is interfaced to a plotting routine and …
Experimental Evaluation Of Design Variables For Two-Dimensional Confined Jet Thrust Vector Control Nozzles, Timothy M. Hawkes
Experimental Evaluation Of Design Variables For Two-Dimensional Confined Jet Thrust Vector Control Nozzles, Timothy M. Hawkes
Theses and Dissertations
An experimental study of the axial and vectoring performance of two - dimensional (2-D) confined jet thrust vector control (CJTVC) nozzles was performed. The effects of adding secondary injection ports and changing exit height and secondary injection port location were studied on several 2-D CJTVC nozzles. The axial and vectoring performance results for these nozzles were measured over a range of pressure ratios. An analytical method for predicting flow separation was found to be applicable to these nozzles. Guidelines for designing 2-D CJTVC nozzles, that can be vectored using secondary injection, were established.
Operations Research In A New Spanish Air Force Planning System, Antonio Valderrabano
Operations Research In A New Spanish Air Force Planning System, Antonio Valderrabano
Theses and Dissertations
The focus of this research effort was to determine a new Spanish Air Force Planning System. Today's highly technological weapon systems are very expensive, and resources are very scarce. So its selection has to be done very carefully. This process can allow high flexibility, be helpful facing the budgetary problems for all the Air Forces, and also can be easily integrated in a joint defense system. The path defined in this thesis is able to be adapted for different situations. It can be useful for other Services or countries, when their own peculiarities have been set up on the defined …
A Vision System Model, Erik J. Fretheim
A Vision System Model, Erik J. Fretheim
Theses and Dissertations
This dissertation provides four major contributions to the field of vision research. The first contribution is a general vision system model. The model, which blends biological as well as technological methods into a coherent approach to vision, will provide a basis for implementing vision systems. The second contribution of this dissertation is to demonstrate particular implementations of portions of the model. These implementations will include methods for using Gabor wavelets in edge detection, in preprocessing images for use as feature vectors in backpropagation neural networks, and as basis functions in a recognition/reconstruction network, as well as methods for integrating color …
A Simulation Analysis Of The Usaf Commissary Customer Service Environment In Support Of Afcoms Store-Level Staff Sizing, Bruce H. Fritz Ii
A Simulation Analysis Of The Usaf Commissary Customer Service Environment In Support Of Afcoms Store-Level Staff Sizing, Bruce H. Fritz Ii
Theses and Dissertations
This Thesis sought to determine the probable impact of the proposed Air Force Commissary Service (AFCOMS) manpower standard for customer service (manpower standard) upon commissary operating environments and to investigate the sensitivity of performance parameters within the customer service system. Specific problems addressed were: (1) Comparison of the cashier manpower requirements calculated by the proposed AFCOMS manpower standard to those determined by a simulation model under similar conditions; (2) Calculation of the expected mean and maximum waiting times in the commissary given the proposed standard; and (3) Determination of the sensitivity of customer waiting time performance measures to variations in …
Transient Heat Transfer Measurements On A Film Cooled Flat Plate In A Shock Tube, Rakhman Gul
Transient Heat Transfer Measurements On A Film Cooled Flat Plate In A Shock Tube, Rakhman Gul
Theses and Dissertations
During this study a simple model of a flat plate was chosen to determine heat flux from a high speed flow behind a shock wave into the film cooled flat plate. An electrical analog was used to convert the output of the heat flux gages into heat flux. Free stream turbulence within the flow behind the shock wave and that generated by a turbulence generator was determined and its effects on the heat transfer data were then studied for comparison with previous experimental work. The thin-film heat flux gages were calibrated and their calibration constants were then used to determine …
A Navigation Reference System (Nrs) Using Global Positioning System (Gps) Aiding, Richard D. Stacey
A Navigation Reference System (Nrs) Using Global Positioning System (Gps) Aiding, Richard D. Stacey
Theses and Dissertations
To quantify the performance abilities of existing or proposed navigation systems, the U.S. Air Force has for the last several years compared the performance of the system under test to the performance of a baseline navigation system known as the Completely Integrated Reference Instrumentation System (CIRIS). CIRIS obtains a highly accurate navigation solution by combining the output from three major subsystems: inertial navigation system (INS) information, barometric altitude information, and range and range-rate data from ground transponders which have been precisely surveyed. Although the navigation solution produced by CIRIS is highly accurate, it will soon be inadequate as the standard …