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Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh Dec 1994

Analysis Of Instability Growth And Collisionless Relaxation In Thermionic Converters Using 1-D Pic Simulations, Bret B. Kreh

Theses and Dissertations

This work investigates the role that the beam-plasma instability may play in a thermionic converter. The traditional assumption of collisionally dominated relaxation is questioned, and the beam-plasma instability is proposed as a possible dominant relaxation mechanism. Theory is developed to describe the beam-plasma instability in the cold-plasma approximation, and the theory is tested with two common Particle-in- Cell (PIC) simulation codes. The theory is first confirmed using an unbounded plasma PIC simulation employing periodic boundary conditions, ES1. The theoretically predicted growth rates are on the order of the plasma frequencies, and ESl simulations verity these predictions within the order of …

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Feasibility Exploration Of Throughfold As A Predictor For Target Loading And Associated Error Bounds, Kris G. Rongone Dec 1994

Feasibility Exploration Of Throughfold As A Predictor For Target Loading And Associated Error Bounds, Kris G. Rongone

Theses and Dissertations

Various applications of the Fredholm integral equation appear m different fields of study. An application of particular interest to the Air Force arises in determination of target loading from nuclear effects simulations. Current techniques first unfold the incident spectrum then determine target loading; resulting spectrum and loading are assumed exact. This study investigates the feasibility of a new method, through-fold, for directly determining defensible error bounds on target loading. Through-fold uses a priori information to define input data and represents target response with a linear combination of instrument responses plus a remainder to derive a quadratic expression for exact target …

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Generation Of A Single-Lobe, Far-Field Intensity Pattern From A Laser Diode Array Using An Optical Delay Line, Thomas A. Summers Dec 1994

Generation Of A Single-Lobe, Far-Field Intensity Pattern From A Laser Diode Array Using An Optical Delay Line, Thomas A. Summers

Theses and Dissertations

A simple and practical technique is demonstrated to generate a stable, single-lobe, far-field intensity pattern from a one-dimensional, antiphased, laser diode array with gain-guided elements. The two far-field lobes of the array are combined after introducing an optical delay line into the path of one of the lobes to make the lobes mutually incoherent. The incoherent superposition of intensities produces a near-diffraction-limited, single-lobe, far-field intensity pattern containing 84% of the power, exceeding any previous (known) phase control experiments. This technique compares favorably with more elaborate schemes advanced previously using integrated phase plates, etc. The method is directly applicable to one-dimensional …

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Artificially Intelligent Air Combat Simulation Agents, Daniel E. Gisselquist Dec 1994

Artificially Intelligent Air Combat Simulation Agents, Daniel E. Gisselquist

Theses and Dissertations

The Advanced Research Projects Agency (ARPA), in an effort to improve military simulations, has proposed a standard for Distributed Interactive Simulation (DIS). This network protocol will allow dissimilar applications to communicate simulation information. In the field of air combat, this will allow pilots in remote simulators to fly in a common simulation. The success of this standard is dependent on applications being able to work within that standard, as well as a large variety of Computer Generated Forces (CGFs) to complement interactive forces. CGFs are needed to help simulate the large combat scenarios that can only occur in wartime. By …

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Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Larch Perspective, Catherine J. Lin Dec 1994

Unification Of Larch And Z-Based Object Models To Support Algebraically-Based Design Refinement: The Larch Perspective, Catherine J. Lin

Theses and Dissertations

This research describes the feasibility of developing object-oriented LARCH specifications, part of a dual approach for formally extending object-oriented analysis models using LARCH and Z. The first phase consisted of two steps establishing a set of transformation heuristics for algebraically representing object models and implementing a robust LARCH parser. The LARCH parser produced abstract syntax trees ASTs of objects forming the basis for analyzing the similarities and differences between Z-based and LARCH-based object representations. The second phase used the analysis of LARCH and Z to identify fundamental core constructs in the languages and abstract syntax trees. These core constructs consisted …

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Next Generation Real-Time Systems: Investigating The Potential Of Partial-Solution Tasks, Robert E. J. Caley Dec 1994

Next Generation Real-Time Systems: Investigating The Potential Of Partial-Solution Tasks, Robert E. J. Caley

Theses and Dissertations

While the cyclic executive and fixed-priority scheduling strategies have been sufficient to handle traditional real- time requirements. they are insufficient for dealing with the complexities of next-generation real-time systems. New methods of intelligent control must be developed for guaranteeing on-time task completion for real-time systems that are faced with unpredictable and dynamically changing requirements. Implementing real-time processes as partial-solution tasks is one technique that may be beneficial. This type of task. when combined with intelligent control, has the potential for increasing pre-runtime schedulability, system maintainability. and runtime robustness. This research investigates the benefits of partial-solution tasks by experimentally measuring the …

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The Photo-Realistic Afit Virtual Cockpit, Milton E. Diaz Dec 1994

The Photo-Realistic Afit Virtual Cockpit, Milton E. Diaz

Theses and Dissertations

The Air Force Institute of Technology (AFIT) has pursued research in virtual environments since 1988. This research expands the current capabilities of the AFIT Virtual Cockpit (VC) by increasing the realism of the cockpit environment and improving the pilot's command interface. Realism is improved creating console elements from texture maps and polygonal models; these elements include working dials, switches and circuit breakers. The pilot command interface is improved in part by adapting the AFIT Information Pod using a two-dimensional mouse input to the virtual three-dimensional environment. This immersive virtual environment is also improved by modifications to the Head Mounted Display …

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Predicting Protein Structure Using Parallel Genetic Algorithms, George H. Gates Jr. Dec 1994

Predicting Protein Structure Using Parallel Genetic Algorithms, George H. Gates Jr.

Theses and Dissertations

The protein folding problem is a biochemistry Grand Challenge problem. The challenge is to reliably predict natural three-dimensional structures of polypeptides. Genetic algorithms (GAs) are robust, semi-optimal search techniques modeling natural evolutionary processes. Fast messy GAs (fmGAs) are variants of messy GAs that reduce the exponential time complexity to polynomial. This investigation evaluates the merits of parallel SGAs and fmGAs for minimizing the potential energy of a pentapeptide, (Met)-enkephalin. AFIT's energy model is compared to a similar model in a commercial package called QUANTA. Differences between the two models are identified and resolved to enhance GAs' abilities to correctly fold …

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Enhanced Visual User Interface Support For Domain-Oriented Application Composition Systems, Richard A. Guinto Dec 1994

Enhanced Visual User Interface Support For Domain-Oriented Application Composition Systems, Richard A. Guinto

Theses and Dissertations

This research refined the functionality and usability of a previously developed visual interface for a domain-oriented application composition system. The refinements incorporated more sophisticated user interface design concepts1 to reduce user workload. User workload was reduced through window reordering, menu redesign, and Human Computer Interaction techniques such as; combining repetitive procedures into single commands, reusing composition information whenever possible and deriving new information from existing information. The Software Refinery environment, including its visual interface tool INTERVISTA, was used to develop techniques for visualizing and manipulating objects contained in a formal knowledge base of objects. The interface was formally validated with …

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Design And Implementation Of Tools To Increase User Control And Knowledge Elicitation In A Virtual Battlespace, Jim J. Rohrer Nov 1994

Design And Implementation Of Tools To Increase User Control And Knowledge Elicitation In A Virtual Battlespace, Jim J. Rohrer

Theses and Dissertations

AFIT's Synthetic BattleBridge is an immersive command observatory for viewing large-area activity within a virtual environment. Three basic areas for improvement are addressed: (1) an improved, immersive, user interface, (2) direct control of atmospheric effects, and (3) improved knowledge elicitation by means of remote viewers, a new space scope, and an enhanced RADAR scope. These requirements are analyzed and implemented. Some functionality was lost but the results show a general improvement of environmental control and knowledge elicitation.

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Analysis Of Modal Behavior At Frequency Cross-Over, Robert N. Costa Jr. Nov 1994

Analysis Of Modal Behavior At Frequency Cross-Over, Robert N. Costa Jr.

Theses and Dissertations

The existence of the mode crossing condition is detected and analyzed in the Active Control of Space Structures Model 4 (ACOSS4). The condition is studied for its contribution to the inability of previous algorithms to successfully optimize the structure and converge to a feasible solution. A new algorithm is developed to detect and correct for mode crossings. The existence of the mode crossing condition is verified in ACOSS4 and found not to have appreciably affected the solution. The structure is then successfully optimized using new analytic methods based on modal expansion. An unrelated error in the optimization algorithm previously used …

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Empiricism, Anatomy, Reality: Reading Herman Melville In The Menippean Tradition., Francis Carter Kaplan Sep 1994

Empiricism, Anatomy, Reality: Reading Herman Melville In The Menippean Tradition., Francis Carter Kaplan

Theses and Dissertations

The purpose of the study is to draw together the art of Herman Melville, Menippean satire, and the empirical tradition in English and Scottish philosophy. Historical and biographical concerns serve as a background for exploring Melville's satire of Platonism, transcendentalism, and hermeneutic apriority. Nathaniel Hawthorne, Edgar Allan Poe, and Washington Irving are discussed in this respect. The dissertation also contains related fiction pieces.The dissertation develops several intertwined conceptions of analysis, drawing together an empirical critical basis derived from Ludwig Wittgenstein and "ordinary language philosophy," the notion of satire as criticism, and the exploration of these concepts through an examination of …

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Reproductive Ecology Of Bighorn Sheep In Alpine And Desert Environments., Christine C. Hass Sep 1994

Reproductive Ecology Of Bighorn Sheep In Alpine And Desert Environments., Christine C. Hass

Theses and Dissertations

This study examines reproductive patterns of two herds of bighorn sheep (Ovis canadensis) in contrasting and extreme environments, to look at the range of variability that exists in certain reproductive traits. Desert bighorn sheep (O. c. nelsoni) were studied in the River Mountains of Nevada, an area characterized by hot, dry summers and mild winters. Rocky Mountain bighorn sheep (O. c. canadensis) were studied in the Pecos Wilderness of New Mexico, an area characterized by cool, wet summers and cold, snowy winters. The objective of the study was to determine lamb production and survival, lamb birth dates, and postnatal maternal …

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The Relationship Between Parental Restrictions And The Occurrence Of Aggressive Behavior In Pre-Adolescent Males., Mary Kathryn Zielinski Sep 1994

The Relationship Between Parental Restrictions And The Occurrence Of Aggressive Behavior In Pre-Adolescent Males., Mary Kathryn Zielinski

Theses and Dissertations

Aggression is one of the most prevalent childhood behavior problems and makes up a large percentage of referrals to psychological clinics. Mental health professionals are likely to recommend that parents of aggressive children set firm rules for their children and that the parents be consistent in enforcing these rules. While this recommendation is suggested by research on parental discipline, there is a relative dearth of information on the relationship between the number of perceived parental rules, the perceived consistency of their enforcement, and the level of aggressive behavior in boys.This study attempted to confirm the importance of consistency in rule …

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Effects Of Alcohol And Attentional Capacity Demands During Picture Viewing., Arlinda Faye Kristjanson Sep 1994

Effects Of Alcohol And Attentional Capacity Demands During Picture Viewing., Arlinda Faye Kristjanson

Theses and Dissertations

Prior research suggests that performing concurrent listening tasks while viewing pictures limits the area of the picture subjects view and the amount they remember. Intoxicated subjects fixate moving objects ignoring other objects more than sober subjects. Both situations demonstrate reduced visual attention. The purpose of this study was to evaluate the effects of alcohol and capacity demands on visual attention by recording the eye movements of sober and intoxicated subjects viewing static scenes while performing a concurrent listening task. Two groups of eighteen subjects (12 male and 6 females each) were tested after they ingested either a lemonade beverage mixed …

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Experiment Using Infrared Spectroscopy To Study The Effect Of Soil Characteristics Upon The Rate Of Trichloroethylene Desorption, Benjamin T. Kindt Sep 1994

Experiment Using Infrared Spectroscopy To Study The Effect Of Soil Characteristics Upon The Rate Of Trichloroethylene Desorption, Benjamin T. Kindt

Theses and Dissertations

This research investigated the influence of soil characteristics on the desorption of trichloroethylene (TCE). TCE is one of the most common contaminants at Superfund sites. Unfortunately, extraction of TCE from contaminated soils has been hindered by its slow and poorly understood desorption from soil particles. The rate and progress of desorption of TCE from seven types of soil with varying particle diameters and elemental compositions was measured using optical absorption techniques. Fitting the data to the Langmuir Isotherm functional form predicted in the literature yielded parameters for the desorption rate and total amount desorption each soil type. These parameters were …

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Modeling Trihalomethane Formation Potential From Wastewater Chlorination, Carol A. Mccormick Sep 1994

Modeling Trihalomethane Formation Potential From Wastewater Chlorination, Carol A. Mccormick

Theses and Dissertations

The deletion of federally mandated fecal coliform limits has led many states to review and modify their wastewater disinfection requirements. One issue in analyzing wastewater disinfection is the discharge of potentially carcinogenic halogenated organics formed during the chlorination process. This research investigates the formation of one class of the halogenated organics, the trihalomethanes. The applicability of using drinking water trihalomethane formation models for use with wastewater effluent is examined. Three models are compared for predictive capability by using measured trihalomethane values from previous research data. The results show that a previously developed model is applicable for use based on assumptions …

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Economics Of Chlorofluorocarbon (Cfc) Machine Replacement, Geoffrey D. Rudderow Sep 1994

Economics Of Chlorofluorocarbon (Cfc) Machine Replacement, Geoffrey D. Rudderow

Theses and Dissertations

Continued use of chlorofluorocarbon CFC refrigerants may have a severe financial as well as operational impact on the users of air-conditioning and other refrigeration equipment as price increases continue and production is phased out. With production of CFCs coming to a halt on 31 December 1995, the two major refrigerants that have been used in commercial and industrial cooling applications will no longer be available. The phase out of production is a result of national and international agreement that these, as well as other CFCs, are a primary cause of the depletion of the stratospheric ozone layer. To help the …

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A Numerical Analysis Of Smoothed Particle Hydrodynamics, David A. Fulk Sep 1994

A Numerical Analysis Of Smoothed Particle Hydrodynamics, David A. Fulk

Theses and Dissertations

This dissertation studies the numerical method of Smoothed Particle Hydrodynamics SPH as a technique for solving systems of conservation equations. The research starts with a detailed consistency analysis of the method. Higher dimensions and non-smooth functions are considered in addition to the smooth one dimensional case. A stability analysis is then performed. Using a linear technique, an instability is found. Solutions are proposed to resolve the instability. Also a total variation stability analysis is performed leading to a monotone form of SPH. The concepts of consistency and stability are then used in a convergence proof. This proof uses lemmas derived …

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Optimal Pulsed Pumping For Aquifer Remediation When Contaminant Transport Is Affected By Rate-Limited Sorption: A Calculus Of Variation Approach, Richard T. Hartman Sep 1994

Optimal Pulsed Pumping For Aquifer Remediation When Contaminant Transport Is Affected By Rate-Limited Sorption: A Calculus Of Variation Approach, Richard T. Hartman

Theses and Dissertations

The remediation of groundwater contamination continues to persist as a social and economic problem due to increased governmental regulations and public health concerns. Additionally, the geochemistry of the aquifer and the contaminant transport within the aquifer complicates the remediation process to restore contaminated aquifers to conditions compatible with health-based standards. Currently, the preferred method for aquifer cleanup pump-and-treat has several limitations including, the persistence of sorbed chemicals on soil matrix and the long term operation and maintenance expense. The impetus of this research was to demonstrate that a calculus of variations approach could be applied to a pulsed pumping aquifer …

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A Retrospective Quantitative Assessment Of Trichloroethylene Exposure Of Workers At Aircraft Maintenance Facilities At Hill Air Force Base Through The Use Of Modeling, Anthony O. Copeland Sep 1994

A Retrospective Quantitative Assessment Of Trichloroethylene Exposure Of Workers At Aircraft Maintenance Facilities At Hill Air Force Base Through The Use Of Modeling, Anthony O. Copeland

Theses and Dissertations

Monte Carlo simulation and source-receptor modeling are used to estimate the TCE exposures encountered by select workers at aircraft maintenance facilities at Hill Air Force Base between 1955 and 1979. An epidemiological study of this group, a retrospective cohort study of 14,457 workers who were employed at the base for a minimum of one year between 1952 and 1956, was headed by Dr. R. Spirtas of the National Cancer Institute to evaluate mortality associated with occupational exposure. One of the major conclusions of the study was that TCE 'probably does not pose a strong carcinogenic risk for man.' In the …

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Cost Management Competencies For Department Of Defense Program Managers, Brent R. Baxter, Kurt R. Bolin Sep 1994

Cost Management Competencies For Department Of Defense Program Managers, Brent R. Baxter, Kurt R. Bolin

Theses and Dissertations

The magnitude of money involved in the acquisition of defense systems and the public scrutiny resulting from cost overruns and program failures make cost management competence critical to program success. This research examined the cost management competencies required of defense program managers. A cost management competency model was developed from a foundation of past research. The model was evaluated through a mail survey of 682 intermediate and senior level military program managers in Air Force Materiel Command. The results provided by the 330 respondents indicate that 29 of the 47 competencies in the model were valuable to the program managers. …

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An Analysis Of Iso 9000'S Applicability To Worldwide Warehouse Quality Assurance, Anthony T. Dyess, Henry E. E. Stish Sep 1994

An Analysis Of Iso 9000'S Applicability To Worldwide Warehouse Quality Assurance, Anthony T. Dyess, Henry E. E. Stish

Theses and Dissertations

This study examines the applicability of ISO 9000, a world-wide quality standard, to the quality assurance procedures being built into a new Foreign Military Sales FMS program. This new program, the Worldwide Warehouse, is an Air Force Security Assistance Center AFSAC attempt to assist FMS customers in reducing excess materiel inventories. Areas of investigation include ISO 9000s international acceptance, its ability to ensure quality products, and a case study of SHARE, a NATO initiative which employs ISO 9000 in quality assurance and is dramatically similar to the Worldwide Warehouse. The researchers conduct an exploratory study using a literature review and …

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Mitigating The Effects Of Manpower Reductions At A Central Issue Facility By Improving The Allocation Of Servers: A Simulation Study, Michael K. Garrity, Christopher J. Wicker Sep 1994

Mitigating The Effects Of Manpower Reductions At A Central Issue Facility By Improving The Allocation Of Servers: A Simulation Study, Michael K. Garrity, Christopher J. Wicker

Theses and Dissertations

The purpose of this research was to determine a preferred server allocation and a preferred customer batch size for processing customers at an Army Central Issue Facility CIF under various manpower levels. The CIF is a retail warehouse which issues tactical clothing and equipment to individual soldiers. It is facing potential manpower reductions from the current level of 19 servers. The CIF exhibits flow shop characteristics. An assembly line balancing approach was used with the objective of reducing the customers average time-in-system. Five server allocation heuristics and three customer batch sizes were examined. The evaluation tool was a computer simulation …

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An Analysis Of The Effects Of Lean Logistics On The Current Air Force Reparable Pipeline: A Simulation Study, Tracey L. Hill, William N. Walker Sep 1994

An Analysis Of The Effects Of Lean Logistics On The Current Air Force Reparable Pipeline: A Simulation Study, Tracey L. Hill, William N. Walker

Theses and Dissertations

This research investigates the effect of Lean Logistics proposals on the current Air Force repairables pipeline. Lean Logistics proposes reducing reparable asset levels at operating bases, reducing transportation time between bases and depots, and reducing depot repair times. Computer simulation is used as a tool to perform a 3X3X3 full factorial experiment to determine the effects of the Lean Logistics proposals on fully mission capable aircraft and transportation cost. Results indicate that lean Logistics outperforms the current repairables pipeline in term of fully mission capable aircraft. A cost benefit analysis is performed to determine the trade offs between transportation costs …

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An Assessment Of Factors That Affect The Employment Of Alternative Dispute Resolution Techniques To Resolve Contract Disputes, Jeffrey T. Journey, Bradley T. Riddle Sep 1994

An Assessment Of Factors That Affect The Employment Of Alternative Dispute Resolution Techniques To Resolve Contract Disputes, Jeffrey T. Journey, Bradley T. Riddle

Theses and Dissertations

This study investigated the factors which potentially influence contracting and legal professionals’ decisions to employ Alternative Dispute Resolution ADR techniques to resolve contract disputes. A literature review revealed that unawareness, excessive oversight, lack of management support, over-regulation, and interdisciplinary conflict on acquisition teams are or have been the most prominent factors discouraging the use of ADR. An additional background investigation determined that the United States Army, the Army Corps of Engineers, and the Navy had extensive experience and expertise regarding ADR use. Therefore, surveys over 250 were administered to various contracting and legal offices throughout these agencies, of which 57 …

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Worldwide Warehouse: A Customer Perspective, Hugo A. Quintero, Carlos A. Valadares Sep 1994

Worldwide Warehouse: A Customer Perspective, Hugo A. Quintero, Carlos A. Valadares

Theses and Dissertations

Under a global climate of increasing economic difficulties and declining defense budget, every opportunity for better use of available resources must be explored. The Worldwide Warehouse WWW Program is being developed as a solution for the excess inventory problem experienced by the Foreign Military Sales FMS countries. The rationale behind the program includes the idea of releasing resources tied to inactive inventory so those resources can be used to improve support and readiness of active inventory. The purpose of this study us to determine to what extent the WWW Program, as initially defined, is perceived by its intended customer the …

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Analysis Of The Jplan Exercise As An Experimental Learning Tool, Mark J. Lynch, Michael E. Washington Sep 1994

Analysis Of The Jplan Exercise As An Experimental Learning Tool, Mark J. Lynch, Michael E. Washington

Theses and Dissertations

The purpose of this study is to develop an effective educational tool for the Combat Logistics course offered at the Air Force Institute of Technology. The current tool being used, the JPLAN Exercise, was identified as outdated in several areas. The research focused upon four investigative questions what makes an effective educational tool, should the existing exercise be revised or replaced, which logistics principles are essential for incorporation into the educational tool, and is the updated tool significantly different from the original. To answer these questions, we conducted an extensive literature review that focused on two areas. The first area …

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Analysis Of The Effects Of Fixed Costs On Learning Curve Calculations, Charles B. Shea, Kenneth P. Thomson Sep 1994

Analysis Of The Effects Of Fixed Costs On Learning Curve Calculations, Charles B. Shea, Kenneth P. Thomson

Theses and Dissertations

The goal of this research was to analyze the effect of fixed costs on learning curve calculations. The research focused on two general research areas. The first area addressed the identification of current cost analysis practice for handling fixed costs in learning curve calculations. After identification of current practice, the unit learning curve models AXb ability to estimate total production run costs for a new production run when the slope was derived from both total cost and variable cost historical lot data was examined. Historical lot cost data was simulated for both the total cost and variable cost cases under …

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Technology Competencies Of Beginning Teachers: A Challenge And Opportunity For Teacher Preparation Programs., Michael Brian Clay Sep 1994

Technology Competencies Of Beginning Teachers: A Challenge And Opportunity For Teacher Preparation Programs., Michael Brian Clay

Theses and Dissertations

This study examined whether teacher preparation programs were producing teachers with appropriate technological skills to compete successfully in the educational marketplace. The research questions were (1) What were the self-reported technology competency levels of teacher preparation program graduates? (2) What were the current expectations by prospective employers of beginning teachers using educational technology? (3) How comparable were the results between the beginning teachers' self-reported technology competencies and the prospective employers' expectations?The 146 beginning teachers in this study were from two teacher preparation (preservice) programs, at Bemidji State University - Bemidji, Minnesota, and at Winona State University - Winona, Minnesota. The …

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