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Articles 541 - 570 of 609
Full-Text Articles in Operational Research
Patient Scheduling And Aircraft Routing For Strategic Aeromedical Evacuation, Michael J. Loftus
Patient Scheduling And Aircraft Routing For Strategic Aeromedical Evacuation, Michael J. Loftus
Theses and Dissertations
The objective of this study is to develop an approach that would assign patients to aeromedical evacuation aircraft and route each aircraft to a single CONUS airport. The goal is to minimize total patient wait time. A heuristic algorithm is developed which exploits the structure of the problem. The first subproblem solved is the assignment of aircraft to airports. This subproblem is solved using integer programming and the results are input into the second subproblem. The second subproblem is the patient to aircraft assignment problem. This subproblem minimizes patient wait time and is solved using network flow programming. The two …
An Interactive Life Cycle Cost Forecasting Tool, Nicolas M. Habash
An Interactive Life Cycle Cost Forecasting Tool, Nicolas M. Habash
Theses and Dissertations
This thesis is about computing life cycle cost and culminates with a life cycle cost forecasting tool (software). The software is written in FORTRAN 77 and uses IMSL subroutine extensively for random number generation from various distributions. The algorithm can compute life cycle cost for the following types of cost elements: constant, stochastic, and cost estimating relationships (CERs). The use of a trapezoid approximation of payment allocation is allowed. Percent allocation of payments is also allowed and is recommended where the trapezoid fails to correctly represent the payment schedule. The CER algorithm handles cost data that was estimated in base …
Analysis Of Whole-Sky Imager Data To Determine The Validity Of Pcflos Models, Richard W. Boltz, George R. Kather
Analysis Of Whole-Sky Imager Data To Determine The Validity Of Pcflos Models, Richard W. Boltz, George R. Kather
Theses and Dissertations
Models used to predict the probability of a cloud-free line-of-sight (PCFLOS) from the ground to space have existed since the 1960s. Unfortunately, an adequate data set has not been available to check the validity of these models until the deployment of the Whole-Sky Imager (WSI) system in 1989. Now that a three-year database has been collected from the WSI system, it is possible to validate, or refute, the existing models. This study investigates the most generally accepted models. Specifically, we investigate three questions: (1) Is the Lund and Shank-lin PCFLOS model assumption of azimuthal independence valid; (2) Does the Lund …
Analysis Of Titan Iv Launch Responsiveness, Michael T. Dunn
Analysis Of Titan Iv Launch Responsiveness, Michael T. Dunn
Theses and Dissertations
This research investigates the feasibility of developing responsive space systems through responsive launch operations with the Titan IV, the only expendable heavy-lift launch vehicle in the United States inventory. A definition for responsive launch has not been firmly established by Air Force Space Command for this launch vehicle. For benchmark purposes, this study uses the responsive launch definition contained in the proposal request for the Medium Launch Vehicle Ill: launch vehicle ignition within 60 days of mission need notification. Titan IV launch processing at Cape Canaveral Air Force Station (CCAFS), Florida currently requires in excess of six months, rendering Titan …
Recurrent Neural Networks For Radar Target Identification, Eric T. Kouba
Recurrent Neural Networks For Radar Target Identification, Eric T. Kouba
Theses and Dissertations
A real-time recurrent learning algorithm was applied to a five class radar target identification problem. The wideband radar was assumed to measure both kinematic (tracking information expressed as estimated aspect angles) and high range resolution data from a single, isolated aircraft. The aspect angles (azimuth and elevation) of the aircraft relative to the radar were assumed to be constantly chancing. This created temporal sequences of high range resolution radar signatures that changed as the aspect angles changed. These sequences were used as input features to a recurrent neural network for three radar target identification test cases. The first test case …
Locating An Imaging Radar In Canada For Identifying Spaceborne Objects, William G. Schick
Locating An Imaging Radar In Canada For Identifying Spaceborne Objects, William G. Schick
Theses and Dissertations
This research presents a study of the maximal coverage p-median facility location problem as applied to the location of an imaging radar in Canada for imaging spaceborne objects. The classical mathematical formulation of the maximal coverage p-median problem is converted into network-flow with side constraint formulations that are developed using a scaled down version of the imaging radar location problem. Two types of network-flow with side constraint formulations are developed: a network using side constraints that simulates the gains in a generalized network; and a network resembling a multi-commodity flow problem that uses side constraints to force flow along identical …
Identification Of The Initial Transient In Discrete-Event Simulation Output Using The Kalman Filter, Mark A. Gallagher
Identification Of The Initial Transient In Discrete-Event Simulation Output Using The Kalman Filter, Mark A. Gallagher
Theses and Dissertations
Data truncation is a commonly accepted method of dealing with initialization bias in discrete-event simulation. Algorithms for determining the appropriate initial-data truncation point for univariate and multivariate output are proposed. The techniques entail averaging across replications and estimating a steady-state output model in a state-space framework. Using the estimated model, Multiple Model Adaptive Estimation (MMAE), which uses Kalman filters with different parameter vectors, is applied. Based on the filters' residuals, the conditional probabilities of each filter's specific parameter vector being correct are determined. The MMAE parameter estimates are the probabilistic- weighted average of the filters' assumed parameter vectors. The estimated …
A Model Of Global Positioning System (Gps) Master Control Station (Mcs) Operations, David N. Koster
A Model Of Global Positioning System (Gps) Master Control Station (Mcs) Operations, David N. Koster
Theses and Dissertations
The United States Air Force's Navstar Global Positioning System (GPS) provides high-accuracy space-based navigation and time distribution to suitably- equipped military and civilian users. The system consists of earth-orbiting satellites and a world-wide network of ground stations. A single operational control center, the GPS Master Control Station (MCS) monitors, maintains, and commands the GPS satellite constellation. The on-going deployment of the complete satellite constellation and recent changes in the operational crew structure may invalidate previously used planning and management paradigms. There is currently no analytical method for predicting the impact of these and other environmental changes on system parameters and …
Retinal Modeling: Segmenting Motion From Spatio-Temporal Inputs Using Neural Networks, David E. Swanson
Retinal Modeling: Segmenting Motion From Spatio-Temporal Inputs Using Neural Networks, David E. Swanson
Theses and Dissertations
We applied two first-order, linear, time-varying, differential equations to the task of segmenting motion from sequences of images. The equations are modified Grossberg formulas for long-term and short-term memory models characterizing the neurotransmitter and cell-activity levels of a synapse and neuron. We described how a two layered, sensory, neural network can be built using the equations to simulate the amacrine neurons of the retina. The model is defined using adaptive input nodes (adaptive model) and is compared to a similar model without these nodes (O and G model). By replicating the basic amacrine neuron model to form both one- and …
An Analysis Of Usspacecom's Space Surveillance Network (Ssn) Sensor Tasking Methodology, Jeff M. Berger, Joseph B. Moles, David G. Wisley
An Analysis Of Usspacecom's Space Surveillance Network (Ssn) Sensor Tasking Methodology, Jeff M. Berger, Joseph B. Moles, David G. Wisley
Theses and Dissertations
This study provides the basis for the development of a cost/benefit assessment model to determine the effects of alterations to the Space Surveillance Network (SSN) on orbital element (OE) set accuracy. It provides a review of current methods used by NORAD and the SSN to gather and process observations, an alternative to the current Gabbard classification method, and the development of a model to determine the effects of observation rate and correction interval on OE set accuracy. The proposed classification scheme is based on satellite J2 perturbations. Specifically, classes were established based on mean motion, eccentricity, and inclination Since J2 …
A Methodology For Model Comparison Using The Theater Simulation Of Airbase Resources And All Mobile Tactical Air Force Models, Heston R. Hicks, Lawrence L. Long
A Methodology For Model Comparison Using The Theater Simulation Of Airbase Resources And All Mobile Tactical Air Force Models, Heston R. Hicks, Lawrence L. Long
Theses and Dissertations
This research compares the Theater Simulation of Airbase Resources (TSAR) model to the sortie generation (SORGEN) module of the AH Mobile Tactical Air Force (AMTAF) model, qualitatively and quantitatively, while concurrently developing and proving a model co methodology. The qualitative analysis compares the models' background and documentation, features and databases, and useability. The quantitative analysis statistically compares the models' estimates of sorties generated. For the quantitative study, eight variables are chosen and assigned high and low values for use in a 2' 1/4 fractional factorial experimental design. Equivalent input databases are developed from a TSAR F-15C database and pilot trials …
An Analysis Of The Air Force Enlisted Performance Feedback System, Dee J. Jackson, Mark A. Ward
An Analysis Of The Air Force Enlisted Performance Feedback System, Dee J. Jackson, Mark A. Ward
Theses and Dissertations
This research evaluated the effectiveness of the enlisted evaluation performance feedback system. The Air Force created the feedback system because many airmen, especially those in lower ranks, did not know or did not understand their duties. Therefore, for the purpose of this study, effectiveness was defined as the degree to which the Air Force model mimicked the ideal feedback model as formulated by the researcher's analysis of the literature. The researchers found evidence that the new Air Force feedback system is an improvement over the old design. Under the old system, the only regulated means of providing feedback was a …
Demonstrating The Effects Of Shop Flow Process Variability On The Air Force Depot Level Reparable Item Pipeline, Marvin A. Arostegui Jr., Jon A. Larvick
Demonstrating The Effects Of Shop Flow Process Variability On The Air Force Depot Level Reparable Item Pipeline, Marvin A. Arostegui Jr., Jon A. Larvick
Theses and Dissertations
This study investigated the effects of reducing the mean processing time and variability in the Shop Flow Segment of the Depot Level Reparable Item pipeline. The measure of interest was the average number of units in the pipeline of a particular type of item (referred to as the average pipeline contents). A literature review revealed that process variability in the pipeline has an impact on its effective operation and cost. A simulation model was developed to determine if reducing mean processing time and/or variability in the Shop Flow Segment would result in a reduction in the average pipeline contents. The …
The Theory Of Constraints Applied To Project Scheduling: The Critical Chain Concept Defined, Andrew D. Ingram, Paul E. Scherer
The Theory Of Constraints Applied To Project Scheduling: The Critical Chain Concept Defined, Andrew D. Ingram, Paul E. Scherer
Theses and Dissertations
This research applies the Theory of Constraints' principles to a project management environment. The Constraint Theory developed by Dr. Eliyahu M. Goldratt has been successfully applied in many manufacturing settings. Researchers are now beginning to apply Theory of Constraints' principles and techniques outside the manufacturing environment. Specific objectives of this research effort include: to develop and demonstrate a resource constrained project scheduling algorithm based on the Theory of Constraints' principles and techniques: to perform a detailed comparison of the manufacturing and project scheduling environments designed to support algorithm development; and to lay the foundation for additional research in this area …
A Method For Determining Schedule Delay Information In A Channel Cargo Route Network Schedule, Justin E. Moul
A Method For Determining Schedule Delay Information In A Channel Cargo Route Network Schedule, Justin E. Moul
Theses and Dissertations
This research develops a method for measuring schedule effectiveness by determining the amounts of enroute, cargo delay caused by a given aircraft mission schedule. The method is designed to generate information which helps identify flights for which different scheduling might decrease overall cargo delay in the entire network, given that all non-scheduling factors are held constant. The research uses a simplified twelve-airport cargo route network to test the methodology.
Strategic Deterrence In The Post-Start Era, David C. Mccormick
Strategic Deterrence In The Post-Start Era, David C. Mccormick
Theses and Dissertations
With the Soviet Union's fall there have been widespread calls for drastic reductions in the United States military's strategic nuclear forces. Although a major threat to the United States has been greatly reduced, the number of strategic targets will not decrease as rapidly as the number of available weapons. This research considers how the United States should think about strategic forces in the rapidly changing world order of the 1990s. An extensive literature review of deterrence concepts and conventional weapons capabilities is conducted with special attention paid to the role that precision guided munitions played in the 1991 Persian Gulf …
Transformation Of Combat Data In Support Of Battle Trace, Hyoung-Kyu Choi
Transformation Of Combat Data In Support Of Battle Trace, Hyoung-Kyu Choi
Theses and Dissertations
The purpose of this study was to find an appropriate way of characterizing battle data as a function of time. This study was initially designed to remove the numerical instability problem cited in Barr's battle trace methodology as suggested by TRAC-MTRY. The research focused on the instability problem and identifying/recommending a technique that improved the efficiency of computation, and enhanced an analyst's ability to meaningfully interpret the battle trace. Two Lanchester's Square Law based methodologies are introduced and analyzed. The results of this analysis indicate that the battle trace of a constant value generated by Lanchester's Square Law integration seemed …
Visual Information Processing And Response Time In Traffic-Signal Cognition, Hasan H. Demirarslan
Visual Information Processing And Response Time In Traffic-Signal Cognition, Hasan H. Demirarslan
Theses and Dissertations
In man-machine design, it is important to quantify the reaction time components instead of simply determining the lump-sum reaction time to stimulus. The primary purpose of this thesis was to investigate the reaction time components, such as visual perception and muscle response time, and to quantify them by separating from their aggregated sum. The prime example, traffic-signal cognition simulation was used to examine human reaction time to signal change. With a modified computer program that stimulates the driver's approach to the intersection, we measured the subject's reaction times and examined behavioral patterns. Twelve subjects were involved in the experiment. A …
Multilayer Perceptrons For Classification, Lisa M. Belue
Multilayer Perceptrons For Classification, Lisa M. Belue
Theses and Dissertations
Techniques for training, testing, and validating multilayer perceptrons are thoroughly examined. Results obtained using perceptrons are compared and contrasted with two multivariate discriminant analysis techniques- logistic regression and k neighbor. Methods for determining significant input features are investigated and a procedure for examining the confidence to place in the significance of these features is developed. Procedures to evaluate the applicability of high-order feature inputs are examined. These methods and procedures are applied to two very different applications. The first application concerns the prediction of Air Force pilot retention/separation rates for input to force projection models. The second application concerns the …
Causal Univariate Spatial-Temporal Autoregressive Moving Averages (Starma) Modelling Of Target Information To Generate Tasking Of A World-Wide Sensor System, Kelly A. Greene
Theses and Dissertations
The Department of Defense employs a resource limited world-wide sensor system to detect certain events of interest. The purpose of this research was to establish a methodology using a univariate causal STARMA model for forecasting the relative probability of an event occurring in a geographical location during a time block of the day. These relative probabilities are used as input for a tasking model that assigns the scarce sensor resources so as to optimize the detection of these events. The STARMA model is appropriate for forecasting the relative probabilities because a definite temporal relationship and a definite spatial relationship exists …
Developing Cmmca Flight Profiles For Cruise Missile Tracking, Andrew C. Hachman
Developing Cmmca Flight Profiles For Cruise Missile Tracking, Andrew C. Hachman
Theses and Dissertations
The Air Force has recently acquired two aircraft dedicated for cruise missile tracking. These aircraft, known as the Cruise Missile Mission Control Aircraft (CMMCA), are responsible for collecting data from the missile and United States. Due to tracking and positively controlling the missile during live fire testing over the western the limited tracking radar range and the flight characteristics of the CMMCA, tracking cruise missiles through complex maneuvers is not always possible. A FORTRAN optimization, based on flight simulation and optimal control theory, was written in a prior thesis effort in order to determine optimal CMMCA flight profiles for tracking …
An Analysis Of Escort Formations, Mustafa Ilhan
An Analysis Of Escort Formations, Mustafa Ilhan
Theses and Dissertations
This study used computer simulation to investigate escort fighter formations unknown interceptor threat environment. A USAF computer simulation model, TAC, was used to simulate air combat between the escorts and the interceptors in several different combat scenarios. The escort formations were defined by the vertical and horizontal distances of the escort fighters from the main strike body. Interceptors were characterized as one of two types of fighters with dissimilar aircraft frames and missile firing ranges. A central composite design was used to mathematically model the effect of escort formations and interceptor type on the survivability of the bombers and escorts. …
Automating The Weekly Flight Scheduling Process At The Usaf Test Pilot School, Gary G. Foster
Automating The Weekly Flight Scheduling Process At The Usaf Test Pilot School, Gary G. Foster
Theses and Dissertations
This study investigated different scheduling solution approaches that could be automated and applied at the USAF Test Pilot School (TPS). Currently at the TPS, flight schedules are manually developed on a daily basis. Weekly flight schedules are not developed due to the large quantity of data that must be processed to develop a flight schedule for an entire week. A weekly flight scheduling approach would reduce the occurrence of scheduling problems and unbalanced resource utilization, both of which are often the result of a daily flight scheduling approach. In addition, posting a flight schedule for the entire week would improve …
An A Priori Multiobjective Optimization Model Of A Search And Rescue Network, Joseph C. Imsand Jr.
An A Priori Multiobjective Optimization Model Of A Search And Rescue Network, Joseph C. Imsand Jr.
Theses and Dissertations
The purpose of this study was to determine the most robust frequency assignment for a search and rescue network. The focus was to assign weights to the transmitter areas of the network to determine which weight sequence produced the most robust frequency assignment. The DoD furnished weight sequences for twelve two-hour time blocks. These weight sequences were compared to a weight sequence with all weights having equal value. Network and linear programming were used to-solve this problem and generate frequency assignments for all weight sequences. Classical and tolerance sensitivity analysis were used to analyze the frequency assignments generated by the …
An Investigation Of Modifications To The Tac Campaign Model, Efgan Denguer
An Investigation Of Modifications To The Tac Campaign Model, Efgan Denguer
Theses and Dissertations
This research investigates the cost and budget modifications to Mixmaster which is an aggregate version of the Theater Attack Model (TAM). Seven simple cost employment methods, a goal programming approach, a probabilistic approach for determining cost coefficients, and goal programming version of that probabilistic approach were applied to Mixmaster. Also, Mixmaster was enhanced with an additional leading constraint to incorporate the Air Force tactical considerations in a campaign scenario. The results favor the advantages of the goal programming approaches. In addition, the probabilistic approach introducing the time factor in the computations promises more accurate results, given that the required parameters …
An Analysis Of The Endurance Of Mobile Satellite Command And Control Systems, Steven O. Brown
An Analysis Of The Endurance Of Mobile Satellite Command And Control Systems, Steven O. Brown
Theses and Dissertations
This study investigated the endurance of a single deployed generic mobile space (GMS) command and control (C2) system. Specifically, factors which affect overall system performance were examined. The analysis began with the development of a simulation model for a GMS C2 system. Optimal settings of factor levels were determined by using the model to find peak system endurance and availability. Factors set were field support vehicle (FSV) access, numbers of maintenance personnel, and numbers of spare components available. After optimum values were chosen for these factors, an experimental design was conducted to determine factor effect between maintenance manpower and the …
Modular Simulation Of Hei Fragments And Blast Pressure, Gordon L. Galloway
Modular Simulation Of Hei Fragments And Blast Pressure, Gordon L. Galloway
Theses and Dissertations
The fragmentation and blast pressure of High Explosive Incendiary projectiles are major causes of aircraft fuel fires. Because Halon 1301 is being banned from DoD use as a fire suppressant, alternative fire suppressants must be developed and tested. These new suppressants must counteract the fire directly or eliminate one or more of the factors which cause the fire. To this end, this thesis takes a detailed look at the HEI processes that lead to a fire. A comprehensive review of the current knowledge and understanding of these processes is presented. In addition, hypothesized dependencies between the various processes are stated. …
Confidence Interval Estimation For Output Of Discrete-Event Simulations Using The Kalman Filter, Randall B. Howard
Confidence Interval Estimation For Output Of Discrete-Event Simulations Using The Kalman Filter, Randall B. Howard
Theses and Dissertations
Discrete-event simulation is computer modeling of stochastic, dynamic systems. The Kalman filter is a Bayesian stochastic estimation algorithm. Because of the correlated nature of simulation output, it is difficult to apply the methods of classical statistics directly when constructing confidence intervals of discrete-event simulation parameters. Through the determination of a dynamics equation and application of the Kalman filter to simulation output data, three new confidence interval construction techniques have been developed. One technique obtains an estimate of the mean value and its associated variance from an estimated Kalman filter. The second technique utilizes Multiple Model Adaptive Estimation (MMAE) techniques to …
Effects Of Facility Configurations And Scheduling Techniques On Aircraft Throughput For Warner Robins Alc Paint/Depaint Facilities, David V. Mcelveen
Effects Of Facility Configurations And Scheduling Techniques On Aircraft Throughput For Warner Robins Alc Paint/Depaint Facilities, David V. Mcelveen
Theses and Dissertations
The purpose of this research was to determine the effects of configuration options and dispatching rules on aircraft throughput for the WR- ALC paint/depaint facilities. A simulation model was constructed and used for this analysis as the primary means to conduct the research. The dispatching rules considered were first come first served, largest number in queue, shortest processing time, and a look ahead heuristic. Due to a reduction in the number of paint aircraft, no configuration option differing from the baseline significantly affected aircraft throughput. Dispatching rules were also found to produce no significant differences on aircraft throughput. Configuration options …
Quantifying The Impact Of The Acquisition Professional Development Program Certification Requirements On The Air Force Institute Of Technology, Paul A. Nicholson
Quantifying The Impact Of The Acquisition Professional Development Program Certification Requirements On The Air Force Institute Of Technology, Paul A. Nicholson
Theses and Dissertations
The purpose of this research is to determine the impact of implementing the Acquisition Professional Development Program on the Air Force Institute of Technology. APDP is part of a DOD-wide effort to decrease inefficiency in the procurement process. The program encompasses a tri-level certification process based on experience, training, and educational standards. APDP serves as a guideline for professional development of acquisition personnel from entry to senior level management. Many of the courses required for certification are offered through AFIT School of Systems and Logistics. Integrating the new educational requirements as a standard for career development is expected to produce …