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Articles 1 - 26 of 26
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Concept Vectors: A Synthesis Of Concept Mapping And Matrices For Knowledge Representation In Intelligent Tutoring Systems, Mark L. Dyson
Concept Vectors: A Synthesis Of Concept Mapping And Matrices For Knowledge Representation In Intelligent Tutoring Systems, Mark L. Dyson
Theses and Dissertations
A review of the literature relating to intelligent tutoring systems (ITS) reveals that the bulk of research to date is focused on the student, and on methods for representing the knowledge itself. From student models to learning schemas to presentation methods, comparatively little attention has been paid to the problem of educators attempting to build viable lesson plans for use in an ITS environment--yet when this problem is addressed in the literature, it is recognized as a potentially daunting one. This thesis addresses the problem of ITS lesson plan development by proposing a practical, computable approach for knowledge engineering that …
Applications Of Unsupervised Clustering Algorithms To Aircraft Identification Using High Range Resolution Radar, Dzung Tri Pham
Applications Of Unsupervised Clustering Algorithms To Aircraft Identification Using High Range Resolution Radar, Dzung Tri Pham
Theses and Dissertations
Identification of aircraft from high range resolution (HRR) radar range profiles requires a database of information capturing the variability of the individual range profiles as a function of viewing aspect. This database can be a collection of individual signatures or a collection of average signatures distributed over the region of viewing aspect of interest. An efficient database is one which captures the intrinsic variability of the HRR signatures without either excessive redundancy typical of single-signature databases, or without the loss of information common when averaging arbitrary groups of signatures. The identification of 'natural' clustering of similar HRR signatures provides a …
Microprogramming A Writeable Control Memory Using Very Long Instruction Word (Vliw) Compilation Techniques, Randall S. Whitman
Microprogramming A Writeable Control Memory Using Very Long Instruction Word (Vliw) Compilation Techniques, Randall S. Whitman
Theses and Dissertations
Microprogrammed Digital Signal Processors (DSP) are frequently used as a solution to embedded processor applications. These processors utilize a control memory which permits execution of the processor's instruction set architecture (ISA). The control memory can take the form of a static, read only memory (ROM) or a dynamic, writeable control memory (WCM), or both. Microcoding the WCM permits redefining the processor's ISA and provides speedup due to its instruction level parallelism (ILP) potential. In the past, code generation efforts for microprogrammable processors focused on creating assembly and microcode as two separate steps. In this thesis an alternative approach was chosen …
A Model For Determining Information To Be Captured Regarding Unauthorized Computer Entry Of An Air Force Computer System, Leslie F. Himebrook
A Model For Determining Information To Be Captured Regarding Unauthorized Computer Entry Of An Air Force Computer System, Leslie F. Himebrook
Theses and Dissertations
This thesis presents a model of information to capture regarding unauthorized computer systems access attempts. This model takes a management focus, and incorporates the technical focus, intelligence focus, and legal focus as inputs. The author used an exploratory, qualitative methodology consisting of an extensive literature review and interviews with experts in the field. These efforts produced the proposed model, which was reviewed by experts in the field using a delphi technique. The model consists of information that is divided into the following areas: 1. What information was compromised. 2. What type of intrusion occurred. 3. How the intrusion was attempted. …
Requirements, Design And Prototype Of A Virtual User Interface For The Afit Virtual Spaceplane, John M. Lewis
Requirements, Design And Prototype Of A Virtual User Interface For The Afit Virtual Spaceplane, John M. Lewis
Theses and Dissertations
The United States Air Force is evaluating the feasibility of designing a military spaceplane capable of accomplishing military objectives from a low earth orbit and atmospheric flight regimes. Current efforts are involved in determining the scientific, operational, and budgetary constraints associated with this concept. This thesis looks at the exploration of new interface techniques associated with the design of a virtual spaceplane and is a subset of the overall virtual spaceplane effort which will assist researchers in determining the feasibility of a military spaceplane. Interface techniques are integrated into a virtual user interface that is designed to accommodate expected operations …
Architecture, Design, And Implementation Of A Rapidly Prototyped Virtual Environment For A Military Spaceplane, Scott A. Rothermel
Architecture, Design, And Implementation Of A Rapidly Prototyped Virtual Environment For A Military Spaceplane, Scott A. Rothermel
Theses and Dissertations
The new Global Engagement vision places increased emphasis on the Air Force's ability to control and exploit space. A military spaceplane combining reliable access to space, high operational tempos, and multi-mission capabilities is in conceptual stages of development. Virtual environment technology provides an opportunity to investigate system requirements and unconventional interface paradigms for this unique vehicle. A virtual environment architecture and design based on support for a rapid prototyping development process, separation of concerns, and user interface development is presented. The rapid prototyping process allowed management of changing requirements via an evolutionary approach to implementation. Separation of the activities performed …
Visualization And Animation Of A Missile/Target Encounter, Jeffrey T. Bush
Visualization And Animation Of A Missile/Target Encounter, Jeffrey T. Bush
Theses and Dissertations
Existing missile/target encounter modeling and simulation systems focus on improving probability of kill models. Little research has been done to visualize these encounters. These systems can be made more useful to the engineers by incorporating current computer graphics technology for visualizing and animating the encounter. Our research has been to develop a graphical simulation package for visualizing both endgame and full fly-out encounters. Endgame visualization includes showing the interaction of a missile, its fuze cone proximity sensors, and its target during the final fraction of a second of the missile/target encounter. Additionally, this system displays dynamic effects such as the …
A Modeling And Simulation Approach To Characterize Network Layer Internet Survivability, Leif S. King
A Modeling And Simulation Approach To Characterize Network Layer Internet Survivability, Leif S. King
Theses and Dissertations
The Air Force Core Competency of Information Superiority will be achieved in an age of decreasing AF manpower and corporate expertise. Increased AF reliance on COTS solutions, coupled with nearly ubiquitous points of entry to communication networks, create unique challenges in maintaining the Information Superiority edge. The protection of the internet is part of this equation. The internet supports the daily business traffic of the Air Force. Personnel, finance, and supply data flow through its routers. Controlling an adversary's access to our information systems, either the data, or the hardware and software that control the data and transform it into …
Breast Cancer Mass Detection Using Difference Of Gaussians And Pulse Coupled Neural Networks, Donald A. Cournoyer
Breast Cancer Mass Detection Using Difference Of Gaussians And Pulse Coupled Neural Networks, Donald A. Cournoyer
Theses and Dissertations
CAD, serving as a second reader, has been shown to improve the success of radiologists at detecting breast cancer. This thesis will develop a new algorithm to identify masses in mammograms. The system developed for this thesis will be capable of assisting a radiologist in making decisions.
A Representational Approach To Knowledge And Multiple Skill Levels For Broad Classes Of Computer Generated Forces, Larry J. Hutson
A Representational Approach To Knowledge And Multiple Skill Levels For Broad Classes Of Computer Generated Forces, Larry J. Hutson
Theses and Dissertations
Current computer generated forces (CGFs) in the 'synthetic battlespace', a training arena used by the military, exhibit several deficiencies. Human actors within the battlespace rapidly identify these CGFs and defeat them using unrealistic and potentially fatal tactics, reducing the overall effectiveness of this training arena. Simulators attached to the synthetic battlespace host local threat systems, leading to training inconsistencies when different simulators display the same threat at different levels of fidelity. Finally, current CGFs are engineered 'from the ground up', often without exploiting commonalities with other existing CGFs, increasing development (and ultimately training) costs. This thesis addresses these issues by …
Modeling And Simulation Support For Parallel Algorithms In A High-Speed Network, Dustin E. Yates
Modeling And Simulation Support For Parallel Algorithms In A High-Speed Network, Dustin E. Yates
Theses and Dissertations
This thesis investigates the ability of a simulation model to compare and contrast parallel processing algorithms in a high-speed network. The model extends existing modeling, analysis, and comparison of parallel algorithms by providing graphics based components that facilitate the measurement of system resources. Simulation components are based on the Myrinet local area network standard. The models provide seven different topologies to contrast the performance of five variations of Fast Fourier Transform (FFT) algorithms. Furthermore, the models were implemented using a commercially developed product that facilitates the testing of additional topologies and the investigation of hardware variations. Accurate comparisons are statistically …
An Examination Of Multi-Tier Designs For Legacy Data Access, Michael L. Acker
An Examination Of Multi-Tier Designs For Legacy Data Access, Michael L. Acker
Theses and Dissertations
This work examines the application of Java and the Common Object Request Broker Architecture (CORBA) to support access to remote databases via the Internet. The research applies these software technologies to assist an Air Force distance learning provider in improving the capabilities of its World Wide Web-based correspondence system. An analysis of the distance learning provider's operation revealed a strong dependency on a non-collocated legacy relational database. This dependency limits the distance learning provider's future web-based capabilities. A recommendation to improve operation by data replication is proposed, and the implementation details are provided for two alternative test systems that support …
An Incompleteness Handling Methodology For Validation Of Bayesian Knowledge Bases, David J. Bawcom
An Incompleteness Handling Methodology For Validation Of Bayesian Knowledge Bases, David J. Bawcom
Theses and Dissertations
The PESKI (Probabilities, Expert Systems, Knowledge, and Inference) system attempts to address some of the problems in expert system design through the use of the Bayesian Knowledge Base (BKB) representation. Knowledge gathered from a domain expert is placed into this framework and inferencing is performed over it. However, by the nature of BKBs, not all knowledge is incorporated, i.e. the representation need not be a complete representation of all combinations and possibilities of the knowledge, as this would be impractical in many real-world systems. Therefore, inherent in such a system is the problem of incomplete knowledge, or spaces within the …
Developing A Corpus Specific Stoplist Using Quantitative Comparison, Craig N. Berg
Developing A Corpus Specific Stoplist Using Quantitative Comparison, Craig N. Berg
Theses and Dissertations
We have become overwhelmed with electronic information and it seems our situation is not going to improve. It is becoming increasingly common for people to work with information on a daily basis. We seem to spend more and more time looking for information, and it is taking longer because more information is available. This thesis will look at how we can provide faster access to the information we want to find. Today's requirements are closely related to searching for information using queries. At the heart of the query process is the removal of search terms having little or no significance …
Pseudorandom Code Generation For Communication And Navigation System Applications, John F. Brendle Jr.
Pseudorandom Code Generation For Communication And Navigation System Applications, John F. Brendle Jr.
Theses and Dissertations
This research project investigated the design, construction and evaluation of a pseudorandom code generator for communication and navigation system applications. These types of codes include spreading codes, Gold codes, Jet Propulsion Laboratory (JPL) ranging codes, syncopated codes, and nonlinear codes. Such waveforms are typically used in communication and navigation system applications. The code generator uses the Stanford Telecom STEL-1032 Pseudorandom Number (PRN) coder. A coder interface was designed and constructed for manual data entry to the registers of the PRN coder. The code generator is capable of independently clocking and generating all possible codes with lengths up to 4,294,967,295 bits. …
A Single Chip Low Power Implementation Of An Asynchronous Fft Algorithm For Space Applications, Bruce W. Hunt
A Single Chip Low Power Implementation Of An Asynchronous Fft Algorithm For Space Applications, Bruce W. Hunt
Theses and Dissertations
A fully asynchronous fixed point FFT processor is introduced for low power space applications. The architecture is based on an algorithm developed by Suter and Stevens specifically for a low power implementation. The novelty of this architecture lies in its high localization of components and pipelining with no need to share a global memory. High throughput is attained using large numbers of small, local components working in parallel. A derivation of the algorithm from the discrete Fourier transform is presented followed by a discussion of circuit design parameters specifically, those relevant to space applications. The generic architecture is explained with …
Subjective Quality Of Experience With The Internet: Accounting For Temporal Changes In User Acceptance Of Information Technology, Jason M. Turner
Subjective Quality Of Experience With The Internet: Accounting For Temporal Changes In User Acceptance Of Information Technology, Jason M. Turner
Theses and Dissertations
Contemporary information technology (IT) related research has focused on use as a key dependent measure for valuing IT. By understanding the determinants of IT use, we gain descriptive information about successful IT, and prescriptive information for better deploying IT resources. Although there are several competing theories regarding IT use, research findings often cite their inability to account for temporal changes in usage behaviors. This thesis introduces quality of experience as a potential moderator between the determinants of use and actual usage behaviors. A pilot survey concerning Internet usage generated potentially relevant items which were later refined into a questionnaire assessing …
An Investigation Into The Use Of Software Product Metrics For Cobol Systems, Richard E. Boone
An Investigation Into The Use Of Software Product Metrics For Cobol Systems, Richard E. Boone
Theses and Dissertations
This thesis investigated several hypotheses that specific product measures could be used to predict later software lifecycle process or product measures. It collected software product and process measures from four consecutive major releases of a large Cobol legacy system (400K LOC). The types of product measures used were size and specific complexity measures. A statistical software package was used to calculate sample correlation coefficients between the measures. A 95% confidence interval was computed for each sample correlation coefficient that showed a strong or moderate linear correlation. The maintenance process measures provided were manhours used for each program changed or added, …
Extracting Functionally Equivalent Object-Oriented Designs From Legacy Imperative Code, Ricky E. Sward
Extracting Functionally Equivalent Object-Oriented Designs From Legacy Imperative Code, Ricky E. Sward
Theses and Dissertations
This research defines a methodology for automatically extracting functionally equivalent object-oriented designs from legacy imperative programs. The Parameter-Based Object Identification (PBOI) methodology is based on fundamental ideas that relate programs written in imperative languages such as C or COBOL to objects and classes written in object-oriented languages such as Ada 95 or C ++. Transformations have been developed that formalize the PBOI methodology and a formal proof is provided showing the extracted object-oriented design is functionally equivalent to the legacy imperative system. To focus the task of re-engineering, generic models of imperative programming languages and object-oriented programming languages have been …
Calibration And Validation Of The Checkpoint Model To The Air Force Electronic Systems Center Software Database, Thomas C. Shrum
Calibration And Validation Of The Checkpoint Model To The Air Force Electronic Systems Center Software Database, Thomas C. Shrum
Theses and Dissertations
This research effort focused on the calibration and validation of CHECKPOINT Version 2.3.1, a computerized software cost estimating tool, to the USAF Electronic Systems Center (ESC) software database. This thesis is a direct follow-on to a 1996 CHECKPOINT study at the Air Force Institute of Technology, which successfully calibrated and validated CHECKPOINT to the SMC software database. While this research generally parallels the methodology in the aforementioned study, it offers advancements in the CHECKPOINT calibration and validation procedure, and it refines the data stratification process and the statistical analyses employed. After stratifying the ESC software database into ten usable data …
Autonomous Construction Of Multi Layer Perceptron Neural Networks, Thomas F. Rathbun
Autonomous Construction Of Multi Layer Perceptron Neural Networks, Thomas F. Rathbun
Theses and Dissertations
The construction of Multi Layer Perceptron (MLP) neural networks for classification is explored. A novel algorithm is developed, the MLP Iterative Construction Algorithm (MICA), that designs the network architecture as it trains the weights of the hidden layer nodes. The architecture can be optimized on training set classification accuracy, whereby it always achieves 100% classification accuracies, or it can be optimized for generalization. The test results for MICA compare favorably with those of backpropagation on some data sets and far surpasses backpropagation on others while requiring less FLOPS to train. Feature selection is enhanced by MICA because it affords the …
Physiologically-Based Vision Modeling Applications And Gradient Descent-Based Parameter Adaptation Of Pulse Coupled Neural Networks, Randy P. Broussard
Physiologically-Based Vision Modeling Applications And Gradient Descent-Based Parameter Adaptation Of Pulse Coupled Neural Networks, Randy P. Broussard
Theses and Dissertations
In this research, pulse coupled neural networks (PCNNs) are analyzed and evaluated for use in primate vision modeling. An adaptive PCNN is developed that automatically sets near-optimal parameter values to achieve a desired output. For vision modeling, a physiologically motivated vision model is developed from current theoretical and experimental biological data. The biological vision processing principles used in this model, such as spatial frequency filtering, competitive feature selection, multiple processing paths, and state dependent modulation are analyzed and implemented to create a PCNN based feature extraction network. This network extracts luminance, orientation, pitch, wavelength, and motion, and can be cascaded …
Object Matching Using The Dynamic Programming Algorithm, Rhoda Baggs Koss
Object Matching Using The Dynamic Programming Algorithm, Rhoda Baggs Koss
Theses and Dissertations
A new algorithm for matching objects between images is developed and investigated. Affine transformations, i.e. those with translation, rotation, scaling and shearing between images are considered. Steps along the way include segmentation of the 2 images (referred to as the reference and inspected images), contour tracing of each segment/object in each image, the creation of objects via a new object representation scheme known as length codes (developed in [3]), and the application of the new dynamic warping algorithm. New original concepts include the use of the dynamic warping algorithm on sequences of length codes in order to determine the k …
Analyzing And Improving Stochastic Network Security: A Multicriteria Prescriptive Risk Analysis Model, David L. Lyle
Analyzing And Improving Stochastic Network Security: A Multicriteria Prescriptive Risk Analysis Model, David L. Lyle
Theses and Dissertations
This research optimized two measures of network security by hardening components and improving their reliability. A common measure of effectiveness (MOE) for networks is statistical reliability, which ignores the effects of hostile actions. A new MOE which includes hostile actions was developed. Both measures require component reliability functions, derived using fault trees. Fuzzy Logic and Monte Carlo simulation were used to quantify uncertainty. Results from the model are compared to traditional Risk Assessment results.
Net-Centric Design And Analysis Of Information Systems, Timothy R. Schmoyer
Net-Centric Design And Analysis Of Information Systems, Timothy R. Schmoyer
Theses and Dissertations
This thesis presents a unique methodology merging state of the art Internet and distributed database technology to support distributed simulations with programming language and platform independence. Standardized models of Command, Control, Communications, Computers, and Intelligence (C4I) systems using Integrated Definition (IDEF) models and executable simulation objects are placed in database repositories which can be accessed and implemented over a distributed simulation network using the Common Object Request Broker Architecture (CORBA). The CORBA distributed simulation network accesses heterogeneous distributed databases, performs distributed processes, and supports portability and reuse of simulation objects and interoperability across operating systems and programming languages.
Response Surface Methodology: An Analytical Method For Locating Migrated Contaminant Sources, Orlando J. Dona Jr.
Response Surface Methodology: An Analytical Method For Locating Migrated Contaminant Sources, Orlando J. Dona Jr.
Theses and Dissertations
The use and storage of hazardous chemicals at U.S. military facilities often adversely affect the groundwater when contaminants infiltrate the subsurface as a result of leaks and accidental spills. These contaminants, if not located and remediated in a relatively short time, may move and settle unpredictably, essentially creating a source some distance from the original leak or spill. An example of this phenomenon is found with migrating dense nonaqueous phase liquid (DNAPL) contaminants. Although various methods for estimating the present day locations of these migrated contaminants are in use, accurately pinpointing the source of contaminants remains a difficult problem in …