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Air Force Institute of Technology

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Power Analysis In Flexible Automation, Nathan A. Titus Dec 1992

Power Analysis In Flexible Automation, Nathan A. Titus

Theses and Dissertations

The performance of an automation or robotic device can be measured in terms of its power efficiency. Screw theory is used to mathematically define the task instantaneously with two screws. The task wrench defines the effect of the device on its environment, and the task twist describes the motion of the device. The tasks can be separated into three task types: kinetic, manipulative, and reactive. Efficiency metrics are developed for each task type. The output power is strictly a function of the task screws, while device input power is shown to be a function of the task, the device Jacobian, …

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Data Reduction With Least Squares Differential Correction Using Equinoctial Elements, Michael S. Wasson Dec 1992

Data Reduction With Least Squares Differential Correction Using Equinoctial Elements, Michael S. Wasson

Theses and Dissertations

This study investigates earth satellite orbit estimation on a track of range, azimuth, and elevation data from a single tracking station. The estimation routine is a least squares batch filter based solely on two-body orbital motion. Using equinoctial elements for the reference orbit avoids the numerical difficulties of the classical elements at eccentricities near zero and inclinations near zero or 90 degrees. Orbits for Mir, DMSP, Explorer, Cosmos, and GPS are investigated. The goal of this study is to reduce orbit information from observations (range, azimuth, and elevation) to an element set and a covariance matrix without considering perturbation effects. …

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Stratified Plate Model For Composite Plate Analysis, Richard A. Coveno Dec 1992

Stratified Plate Model For Composite Plate Analysis, Richard A. Coveno

Theses and Dissertations

This study continues the investigation of the stratified plate model for the analysis of composites plates. The strata theory models a composite plate as a stack of isotropic matrix and orthotropic, fiber dominated layers. Energy methods are used to derive a set of partial differential equations and boundary conditions as a function of the displacement. An assumed displacement field, of a polynomial in z and a Sine/Cosine function in x and y, generates a solution to a simply supported composite plate with cross plies. A cylindrical bending example is also solved with a polynomial in z and Sine/Cosine function in …

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The Non-Linear Dynamics Of Composite Cylindrical Shells, James M. Greer Jr. Dec 1992

The Non-Linear Dynamics Of Composite Cylindrical Shells, James M. Greer Jr.

Theses and Dissertations

The non-linear dynamic behavior of suddenly loaded composite shells is the subject of this research. The objective of research is two-fold: (1) to characterize the apparently random physical behavior sometimes observed in the finite element analysis as either numerical instability, chaotic behavior, or both; and (2) to develop criteria for choosing time steps for the finite element model, referred to as DSHELL. This displacement based finite element code is capable of dynamic analysis of plates, arches, and cylindrical shells undergoing large displacements and moderately large rotations during deformation. DSHELL uses a 36-DOF isoparametric shell element to obtain numerical results. A …

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Experimental Investigation Of The Aerodynamics Of Independently Rotating Cylindrical Shells, Walter C. Howerton Dec 1992

Experimental Investigation Of The Aerodynamics Of Independently Rotating Cylindrical Shells, Walter C. Howerton

Theses and Dissertations

The purpose of this thesis was to investigate experimentally the aerodynamic forces on two adjacent, independently rotating cylinders in a cross- flow. This investigation involved a force measurement setup which had the two cylinders mounted on a common support shaft, extending beyond the span of the wind tunnel test section, and supported by spoke rings with strain gages in the vertical and horizontal directions. This setup proved capable of measuring aerodynamic forces. The lift on the independently rotating cylinders was found to increase as one cylinder's angular speed increased while the other's remained constant, and decrease as the relative angular …

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Optimal Control Of The Starfire Beam Director, Troy V. Lanier Dec 1992

Optimal Control Of The Starfire Beam Director, Troy V. Lanier

Theses and Dissertations

The Starfire Beam Director (SBD) is located at the Starfire Optical Range at Kirtland Air Force Base in Albuquerque, New Mexico. The SBD capabilities include tracking celestial objects and active or passive tracking of artificial satellites to support the Phillips Laboratory Ground Based Laser Acquisition, Tracking, and Pointing (GBL ATP) program. The pointing and tracking accuracy needed to support such experiments is micron rad to sub-grad level. To accomplish this goal requires precise pointing of the massive 6 ton 1 -meter clear aperture coelostat. The purpose of this thesis is to use optimal control design techniques to develop a controller …

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Vibration Suppression In Large Flexible Space Structures Using Active Control Techniques, Chad T. Matheson Dec 1992

Vibration Suppression In Large Flexible Space Structures Using Active Control Techniques, Chad T. Matheson

Theses and Dissertations

This report investigates the use of active vibration control techniques applied to the PACOSS Dynamic Test Article as an experimental structure. In the course of the research, a mathematical model of the lightly damped experimental structure was created based on experimental data. This model was used in the design of two classes of controllers. The first class is pure rate feedback of the structure's measured states such that global stability is insured. The second type of controller investigated was an optimal controller (LQG) that was created using the truncated mathematical model. The rate feedback controller showed significant improvements in the …

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The Influence Of Structural Optimization On The Aeroelastic Properties Of A Vertical Tail, David G. Miller Dec 1992

The Influence Of Structural Optimization On The Aeroelastic Properties Of A Vertical Tail, David G. Miller

Theses and Dissertations

The purpose of this thesis is to investigate the influence of structural optimization parameters on the structural and aeroelastic behavior of a vertical tail. The outside geometry of the tail is assumed fixed. The objective of the optimization is to reduce the structural member sizes so that the overall weight of the tail is minimized. The influence that design loads, design constraints, design variable linking has on the optimal design is observed examining several design cases. The static aeroelastic properties a flutter speeds of the various design cases are then compared. The doublet lattice method is used to calculate the …

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Application Of The Program Profile For The Design Of Low-Speed, Low- Observable Configuration Airfoils, Gregory A. Sharp Dec 1992

Application Of The Program Profile For The Design Of Low-Speed, Low- Observable Configuration Airfoils, Gregory A. Sharp

Theses and Dissertations

This study investigated-the use of the program PROFILE for the design of low-speed, low-observable configuration airfoils. For our purposes, low- observable configuration is defined as being characterized by a small leading- edge radius of less than 1.18 percent chord and a thickness-to-chord ratio of 2. 5 to 5.5 percent. A methodology was developed whereby the input parameters to prescribe the velocity distribution over the airfoil could be determined by a power law relationship. This relationship enables the designer to develop symmetric airfoils with the desired thickness-to-chord and leading-edge radius within the stated constraints. The resulting symmetric airfoils compared very well …

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Helicopter Flight Control System Design Using The Linear Quadratic Regulator For Robust Eigenstructure Assignment, Dempsey D. Solomon Dec 1992

Helicopter Flight Control System Design Using The Linear Quadratic Regulator For Robust Eigenstructure Assignment, Dempsey D. Solomon

Theses and Dissertations

This thesis applied modern, multi-variable control design techniques, via a FORTRAN computer algorithm, to U.S. Army helicopter models in hovering flight conditions. Eigenstructure assignment and Linear Quadratic Regulator (LQR) theory are used to achieve enhanced closed loop performance and stability characteristics with full state feedback. The addition of cross coupling weights to the standard LQR performance index is specifically addressed. A desired eigenstructure is chosen with a goal of reduced pilot workload via performance qualities requirements. Cross coupling weighting is shown to provide greater flexibility in achieving a desired closed loop eigenstructure. While the addition of cross coupling weighting is …

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Computational And Experimental Investigation Into Fracture Of Brittle Fiber - Brittle Matrix Composite Systems, James P. Solti Dec 1992

Computational And Experimental Investigation Into Fracture Of Brittle Fiber - Brittle Matrix Composite Systems, James P. Solti

Theses and Dissertations

Experimental and computational analyses provided an improved understanding of quasi-static fracture in model composite systems. Constant displacement compression tests using borosilicate glass double cleavage drilled compression test templates provided qualitative assessments of localized toughening for crack growth near cylindrical inclusions. Large crack-tip stress fields induced interfacial slip and separation prior to arrival of the main crack. Debonding and the proliferation of secondary matrix cracks characterized the role of bridging fibers along weak interfaces. Strong residual normal compressive interfacial stresses diminished the influence of crack-tip stresses; however, slip was still observed. VHS tape and computer enhanced photos record a history of …

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Behavior Of A Centrally Notched Cross-Ply And Unidirectional Ceramic Matrix Composite In Tension-Compression Fatigue, William A. Weidenaar Dec 1992

Behavior Of A Centrally Notched Cross-Ply And Unidirectional Ceramic Matrix Composite In Tension-Compression Fatigue, William A. Weidenaar

Theses and Dissertations

Centrally notched (hole), cross-ply, ((0/90)2)s, and unidirectional, (0)8 laminates of Silicon Carbide fiber-reinforced Aluminosilicate glass, SiC/1723, were fatigue tested under tension-compression loading with a load ratio of -1. Damage accumulated continuously for both lay- ups, leading to eventual failure and a reduced fatigue life. Critical damage in the cross-ply consisted of longitudinal cracks in the 90° plies growing and combining with transverse cracks to effectively eliminate the 90° plies' load carrying capability and allowing the specimen to buckle. Critical damage in the unidirectional lay-up consisted of longitudinal cracks which initiated at the shear stress concentration …

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Object-Oriented Analysis, Design, And Implementation Of The Saber Wargame, David S. Douglass Dec 1992

Object-Oriented Analysis, Design, And Implementation Of The Saber Wargame, David S. Douglass

Theses and Dissertations

Saber is a two-sided, air and land war game that simulates decisions made of commanders at the theater-level. It is being developed by the Air Force Institute of Technology for the Air Force Wargaming center at Maxwell AFB, Alabama. Saber models conventional, chemical, and nuclear warfare between aggregated air and land forces. It also portrays the effects of logistics, satellites, weather, terrain, and intelligence which add to the realism of the Saber war game. The Saber war game has three main components, the preprocessor. which is responsible for scenario development and pregame activities, the simulation. the guts of the war …

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A Vhdl Interpreter For Model-Based Diagnoses, David R. Griffin Dec 1992

A Vhdl Interpreter For Model-Based Diagnoses, David R. Griffin

Theses and Dissertations

Model-based reasoning permits diagnostic applications to be written without waiting for someone to become an 'expert' of the system. For model-based diagnostics, there must be a model to reason from. This thesis explores using a VHDL description of the system as that model. A system based around a VHDL interpreter was written specifically for a model-based diagnostic algorithm. Currently, the diagnostic system uses an algorithm by Dries. This algorithm was derived from Scarl's Full Consistency Algorithm. The system was designed to be modular so that different diagnostic techniques could be implemented. It is divided into three parts: a VHDL parser, …

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Design And Development Of A High-Speed Winograd Fast Fourier Transform Processor Board, James F. Herron Dec 1992

Design And Development Of A High-Speed Winograd Fast Fourier Transform Processor Board, James F. Herron

Theses and Dissertations

Since 1985, the Air Force Institute of Technology has pursued a project to develop a 4080-point Discrete Fourier Transform processor using the Winograd Fourier Transform Algorithm (WFTA) and Good-Thomas Prime Factoring Algorithm (PFA). In the first attempt to build a working system, this research effort designed and constructed, in part, a modified single processor architecture in order to demonstrate the proof of concept of the WFTA system design. This prototype architecture is simpler in implementation but uses the same principles and procedures as those of the 4080-point WFTA design. The design developed in this thesis was validated using the Very …

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A User Interface To A True 3-D Display Device, Bruce A. Hobbs Dec 1992

A User Interface To A True 3-D Display Device, Bruce A. Hobbs

Theses and Dissertations

This thesis describes an interactive interface to a true three dimensional, real-dm dynamic graphic display, the TI Omniview™. The system generates true 3-D images of volumetric data and objects. The TI Omniview is a cylindrical volumetric laser display that uses a rotating double-helix translucent disk to fill the display cylinder. Voxels are illuminated on the 2-D surface. The rotational speed of the disk allows the viewer to fuse the 2-D images into a true 3-D image. The interface provides the user with a quick and flexible means of manipulating the image generated, the sub-volume displayed, and the resulting 3-D image. …

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An Investigation Of Discovery-Based Learning In The Route Planning Domain, Freeman A. Kilpatrick Jr. Dec 1992

An Investigation Of Discovery-Based Learning In The Route Planning Domain, Freeman A. Kilpatrick Jr.

Theses and Dissertations

This thesis presents MAVERICK, a Discovery-Based learning (DBL) system designed to learn maneuvers in the route planning domain. DBL was originally designed to learn in domains for which little domain knowledge exists. This thesis proposes using it in domains for which knowledge exists, but the acquisition of this knowledge is difficult or time-consuming because of the knowledge acquisition bottleneck. The operation of the DBL process in MAVERICK was investigated to determine the potential utility of such a system to a real- world Air Force problem in the domain of aircraft route planning. MAVERICK worked well in its limited domain, and …

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Generalization And Parallelization Of Messy Genetic Algorithms And Communication In Parallel Genetic Algorithms, Laurence D. Merkle Dec 1992

Generalization And Parallelization Of Messy Genetic Algorithms And Communication In Parallel Genetic Algorithms, Laurence D. Merkle

Theses and Dissertations

Genetic algorithms (GA) are highly parallelizable, robust semi- optimization algorithms of polynomial complexity. The most commonly implemented GAs are 'simple' GAs (SGAs). Reproduction, crossover, and mutation operate on solution populations. Deceptive and GA-hard problems are provably difficult for simple GAs. Messy GAs (MGA) are designed to overcome these limitations. The MGA is generalized to solve permutation type optimization problems. Its performance is compared to another MGA's, an SGA's, and a permutation SGA's. Against a fully deceptive problem the generalized MGA (GMGA) consistently performs better than the simple GA. Against an NP-complete permutation problem, the GMGA performs better than the other …

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Examining A Layered Approach To Function And Design Representation For Reusable Software Components, Paul D. Siebels Dec 1992

Examining A Layered Approach To Function And Design Representation For Reusable Software Components, Paul D. Siebels

Theses and Dissertations

This effort examined ways to improve the effectiveness of reusable software libraries. The main area of investigation was in improving the user interface by finding better ways to present the software components to potential re-users. The first aspect which was considered was finding an effective representation for reusable software components. A set of criteria was developed for evaluating the effectiveness of software representations. The criteria consisted of generality, expressiveness, understandability, consistency, and resolution. The second aspect which was considered was how to present the software component information to the user to facilitate finding the appropriate component for reuse. A representation …

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An Intelligent Real-Time System Architecture Implemented In Ada, Michael A. Whelan Dec 1992

An Intelligent Real-Time System Architecture Implemented In Ada, Michael A. Whelan

Theses and Dissertations

Conventional real-time systems are fully deterministic allowing for off-line, optimal, task scheduling under all circumstances. Real-time intelligent systems add non-deterministic task execution times and non- deterministic task sets for scheduling purposes. Non-deterministic task sets force intelligent real-time systems to trade-off execution time with solution quality during run-time and perform dynamic task scheduling. Four basic design considerations addressing those tradeoffs have been identified: control reasoning, focus of attention, parallelism, and algorithm efficacy. Non-real- time intelligent systems contain an environment sensor, a model of the environment, a reasoning process, and a large collection of procedural processes. Real-time intelligent systems add to these …

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Creating And Manipulating Formalized Software Architectures To Support A Domain-Oriented Application Composition System, Cynthia G. Anderson Dec 1992

Creating And Manipulating Formalized Software Architectures To Support A Domain-Oriented Application Composition System, Cynthia G. Anderson

Theses and Dissertations

This research investigated technology which enables sophisticated users to specify, generate, and maintain application software in domain-oriented terms. To realize this new technology, a development environment, called Architect, was designed and implemented. Using canonical formal specifications of domain objects, Architect rapidly composes these specifications into a software application and executes a prototype of that application as a means to demonstrate its correctness before any programming language specific code is generated. Architect depends upon the existence of a formal object base (or domain model) which was investigated by another student in related research. The research described in this thesis relied on …

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A Model For Determining Task Set Schedulability In The Presence Of System Effects, Rusty O. Baldwin Dec 1992

A Model For Determining Task Set Schedulability In The Presence Of System Effects, Rusty O. Baldwin

Theses and Dissertations

This research developed a parameterized model that accounts for system overhead and determines when an Ada runtime environment can no longer successfully execute a given Ada task set and still meet all deadlines. The Ada Compiler Evaluation Capability benchmark was used to characterize an actual runtime environment. Using that data, a generic model of a preemptive, rate monotonic priority based runtime system was developed which accounts for overhead due to clock updates, context switching, task suspension, and synchronization. Validation was based on the Hartstone benchmark. First, the benchmark was executed using, the actual runtime environment. Then, those results were compared …

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Spatial Partitioning Of A Battlefield Parallel Discrete-Event Simulation, Kenneth C. Bergman Dec 1992

Spatial Partitioning Of A Battlefield Parallel Discrete-Event Simulation, Kenneth C. Bergman

Theses and Dissertations

This thesis describes a method for spatially partitioning a battlefield into units known as sectors to achieve speedup two ways: through the reduction of each battlefield object's next event search space, and lowering the amount of message-passing required. Each sector is responsible for tracking and controlling access to all objects within its boundaries. A distributed proximity detection algorithm employing boundary-crossing events is used to control player movement between sectors. Each object's state information is replicated in all sectors it has sensor capability for the minimum time required; -this ensures that each object's next event is properly determined based upon interactions …

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Formalization And Transformation Of Informal Analysis Models Into Executive Refine™ Specifications, Mary M. Boom, Bradley D. Mallare Dec 1992

Formalization And Transformation Of Informal Analysis Models Into Executive Refine™ Specifications, Mary M. Boom, Bradley D. Mallare

Theses and Dissertations

This research developed and implemented an automated technique for translating informal specifications into formal, executable specifications. A unified Abstract Model (UAM) was developed to combine the information contained in Entity Relationship, State Transition, and Data Flow Models into a concise, object-based representation. The UAM forms the basis for defining a formal language, the Object Modeling Language (OML), used to capture the information contained in the UAM. By using OML, we were able to develop an automated translation process to convert informal specifications into executable, formal specifications. The Software Refinery Development Environment enabled us to easily develop a parser that translates …

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Version And Transaction Management In Osmagic: An Object-Oriented Database Implementation Of The Magic Vlsi Layout Design Tool, Gary M. Lightner Dec 1992

Version And Transaction Management In Osmagic: An Object-Oriented Database Implementation Of The Magic Vlsi Layout Design Tool, Gary M. Lightner

Theses and Dissertations

The goal of this thesis was to study the feasibility of using an object-oriented database management system to provide the functionality and performance needed to support a complex computer-aided design tool. We do this by modifying OSMagic, a prototype system of the Magic very large scale integrated (VLSI) circuit design tool implemented on the ObjectStore object- oriented database management system. OSMagic was changed to support three different interfaces to ObjectStore and to work in a networking environment. We then designed and examined the use of version and transaction management models as a means of addressing the weaknesses of the prototype …

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A Unified Model Of Program Behavior, Douglas T. Michel Dec 1992

A Unified Model Of Program Behavior, Douglas T. Michel

Theses and Dissertations

This thesis is an attempt to account for and unify the three types of locality: temporal, spatial, and structural. A diverse sample of traces are used in measuring program behavior with respect to these localities and a model is presented which represents the memory references a program generates as it goes through execution. The model is validated by estimating, the entropy of a synthetically generated trace and comparing it with actual traces. The results indicate that there is more predictability contained in the original trace than what the model was able to capture. Different variations of the model were tried …

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An Enhanced User Interface For The Saber Wargame, Donald R. Moore Dec 1992

An Enhanced User Interface For The Saber Wargame, Donald R. Moore

Theses and Dissertations

This thesis is part of an on-going effort by the Air Force Institute of Technology to develop a computer-based, theater-level wargame for the Air Force Wargaming Center at Maxwell AFB, AL. The wargame, Saber, is intended to augment the education the students receive at the Air War College and the Air Command and Staff College in the employment of air and ground power. This thesis documents the integrated design and implementation of the two components of the Saber user interface: the pre-processor and the post-processor. Although previous thesis students designed and implemented substantial portions of the user interface, a fully …

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Creating And Manipulating A Domain-Specific Formal Object Base To Support A Domain-Oriented Application Composition System, Mary Anne Randour Dec 1992

Creating And Manipulating A Domain-Specific Formal Object Base To Support A Domain-Oriented Application Composition System, Mary Anne Randour

Theses and Dissertations

This research investigated technology which enables sophisticated users to specify, generate, and maintain application software in domain-oriented terms. To realize this new technology, a development environment, called Architect, was designed and implemented. Using canonical formal specifications of domain objects, Architect rapidly composes these specifications into a software application and executes a prototype of that application as a means to demonstrate is correctness before any programming language specific code is generated. This thesis investigated populating and manipulating the formal object base required by Architect. This object base is built using a domain- specific language (DSL) which serves as an interface between …

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Management Of Simnet And Dis Entities In Synthetic Environments, Steven M. Sheasby Dec 1992

Management Of Simnet And Dis Entities In Synthetic Environments, Steven M. Sheasby

Theses and Dissertations

This thesis describes the techniques used to create an object manager utilized by an application program during a distributed interactive simulation. This work is currently utilized by a number of AFIT synthetic environment applications for use during a SIMNET exercise. An extensive review of distributed interactive simulations is presented. A discussion of the current distributed simulation protocol, SIMNET, is presented along with the future protocol standard, DIS. Finally, a brief discussion on dead reckoning and its importance during an exercise is presented. An analysis of the SIMNET and DIS protocols provided the basis for the creation of a series of …

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A Synthetic Environment Flight Simulator: The Afit Virtual Cockpit, John C. Switzer Dec 1992

A Synthetic Environment Flight Simulator: The Afit Virtual Cockpit, John C. Switzer

Theses and Dissertations

This thesis describes the design and implementation of a part of the Virtual Cockpit: a synthetic environment, distributed network flight simulator. The goal of the project was to prove the concept that this type of flight simulator could fill the gap between high-end, very expensive flight simulators and low-end game quality flight simulators. Discussed are: object-oriented design techniques, multi-processor utilization, the flight dynamics model, synthetic environment technology, the frame-rate vs. realism issue, and the interfaces to a realistic joystick and throttle.

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