Significant documents I wrote during my undergraduate studies at Penn State University (1999 - 2003) and my graduate studies at Old Dominion University (2004 - 2007) are posted below in reverse chronological order. These papers are intended for academic and informational use only.

    Standardized patients are actors used in medical training to teach and evaluate clinical skills of students prior to their using these skills on an actual patient. Augmented Reality is a relatively new technology that can be used to augment standardized patients with abnormalities and pathologies that they cannot portray themselves as normal healthy human beings. In our project, we sought to augment standardized patients with a 12-week-old fetus in order to train and possibly evaluate medical students and professionals in performing obstetric ultrasound procedures and interpreting the corresponding ultrasound image results. The software library ARToolkit provided the framework for our computer application, utilizing a visual tracking system that consisted of merely a single webcam and several black and white pattern targets. OpenGL functions were used to render three-dimensional virtual objects and apply two-dimensional textures. More complex anatomical shapes were created and modified using 3ds Max software and then imported into our program during execution. Our final application featured one view displaying the video frames with superimposed virtual objects, another view exposing all of the virtual objects in three-dimensional space, and a final view showing two-dimensional ultrasound output. We conducted a demonstration and evaluation session using our system with several professionals in the medical education field. While they suggested some refinements to our ultrasound output and real-time processing, their feedback led us to conclude that augmenting standardized patients to appear to be carrying a fetus is possible. The potential to incorporate a wide variety of pathologies into our application provides an additional benefit to the medical education field.

    Abstract – Augmented reality (AR) is the accurate superposition of virtual computer graphics on top of real world images. It can be accomplished through a variety of hardware and software means, relying heavily on visual, magnetic, inertial, or other types of tracking systems to register the virtual objects correctly with real ones. The medical field in particular has found numerous applications for AR technology and in recent years has seen some developmental research projects begin to migrate into actual clinical and surgical use. Our own research pertains to the training and evaluation of medical students performing standard pregnancy sonograms on standardized patients, for which we have begun to develop a training simulation that utilizes the benefits of AR.
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    Introduction - Humans receive visual and auditory sensations from specific organs, namely their eyes and ears. Typical personal computers provide visual and auditory interaction and feedback as their interface. Sensations of force, however, can theoretically come from any part of body. A computer’s interaction with sensations such as these is handled by haptic interfaces. Because of their many uses and many different means of implementation, haptic interfaces can take on a wide variety of shapes and forms, several of which are discussed in this paper. Haptic user interfaces are specifically gaining popularity among the blind and visually impaired, as they enable them to interface with computer through more intuitive means than were traditionally available. Blind people can now learn mathematics by tracing touchable curves, play haptic computer games, and gain better access to graphics user interfaces like Windows and its numerous supporting applications. Because many current screen readers (tools that convert digital text to auditory words) cannot handle graphics, the benefits of the World Wide Web have been largely unavailable to blind and visually impaired people. Those computer tools that are capable of handling graphics are often too expensive for the common user. New advances in haptic interfaces, however, are lowering the price of such hardware and software and are allowing users to actually feel features on a webpage such as links and images while gathering a clearer mental picture of the page’s layout. As will be presented in this paper, haptic interfaces are often combined with auditory interfaces to provide blind and visually impaired people with the most complete computer experience possible. Defining the role of each of these two modalities presents a challenge to the human-computer interface designer [1]. Indeed, making internet content accessible to the blind and visually impaired relies heavily on individual website developers to provide products that are universally accessible. Captology may play a role here as some website developers push to make their site as accessible as possible, persuading others in the open market to do the same.
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    Abstract - Since they were first extensively studied in the sixties, genetic algorithms have demonstrated their innate ability to optimize highly discontinuous, noisy, and non-linear objective functions, particularly those previously found to be unsolvable by traditional means. Through mimicking the processes that biological evolution induces upon chromosomes, genetic algorithms can evolve vast sets of potential solutions in parallel, randomly selecting, mutating, and recombining their data to practically always produce at least one very good solution to the problem at hand. Even though the initial solution set of a genetic algorithm is typically generated randomly, the end result of the simulation process after many iterations, or generations, is distinctly non-random (better than random). While genetic algorithms will never replace traditional optimization methods, it can be used very effectively as both an alternative to and in conjunction with gradient-based means.
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    Abstract - Food is moved from the mouth to the stomach by contractions of circular muscles in the esophageal wall. Traditionally it has been thought that this muscle squeeze was a continuous process. More recent studies have shown that esophageal transport is divided into two primary contraction-wave structures. The goal of this research was to identify further structural divisions in esophageal muscle squeeze and to quantify statistically the characteristics of the secondary contractile structure. Pressures were collected manometrically at 21 locations through the esophageal lumen in 18 healthy subjects by Drs. Janiak and Schwizer in Switzerland. Animations of temporal changes in the spatial distributions of pressure along the esophagus were made using specially designed software within Matlab. “Secondary” pressure waves (SPWs) were found to exist in all subjects, superposed over the primary wave structure and separated by short segmental contractions. SPW speed was half the primary wave speed, on average. SPW and segment lengths were 2-5 cm and 2-4 cm, on average. We conclude that the neurophysiological structure of esophageal muscle contractions is significantly more complex than previously thought and is manifested by a series of shorter contractile segments separated by the SPW structure.
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    Abstract - Tissue engineering today is helping millions of people worldwide combat heart disease through the implantation of vascular grafts. The use of small-intestine submucosa (SIS) in an acellular approach to small-diameter vascular grafts has shown promise in previous experiments. It was analyzed experimentally by outside authors (Roeder et al.) for compliance, modulus of elasticity, and burst pressure and analyzed theoretically here for the same factors plus viscoelasticity and immune response. This study tested for compliance by measuring pressure using fluid-filled pressure transducers while adding fluid volume in controlled increments. In the same process, the drop in pressure over a time period as the graft "adjusts" to the volume rise was recorded. Also, burst pressure was found for various test grafts by connecting a fluid-filled pressure transducer to the grafts and increasing the internal fluid pressure until the grafts rupture. A mathematical model was then developed using graphical analysis and engineering stress and strain equations. It predicted relationships between the graft's internal pressure and diameter and the graft's modulus of elasticity and internal pressure. Maximum, minimum, and mean values for the graft's burst pressure were found, and viscoelasticity was predicted by deriving creep and stress relaxation equations for diameter as a function of pressure and time. Comparisons were drawn between the outside authors' work and the propositions made here. For example, both addressed compliance matching and high burst pressure, but the outside authors did not address viscoelasticity and immune response. Suggestions for improving the work of the outside authors and concurrent reasoning were provided.
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    Executive Summary - The United States Navy has plans for constructing many new nuclear submarines over the next decade. These submarines, while extremely effective throughout the Cold War, may no longer provide the Navy with the mobility, stealth, and cost effectiveness that it desires. For these reasons, non-nuclear submarines may soon replace their nuclear brethren in the production line and the question arises as to what type of non-nuclear submarine such replacements will be. Submarines powered by diesel-electric systems with battery-driven propulsion are quiet beneath the surface, but require a noisy recharging process if battery power runs out. They can reportedly reach underwater sprint speeds around 25 knots and dive to depths of about 400 meters. Construction costs $250 million and maintenance adds significantly more. At over 40%, engine efficiencies are relatively high, allowing diesel-electric submarines to stay submerged for over a month. Stirling engine submarines provide quiet propulsion underwater with no need for noisy battery recharging. They are limited to a speed of 20 knots submerged and can reportedly dive below 450 meters. They cost $100 million to build and rarely require engine maintenance. Submerged endurance lasts several weeks running on Stirling engines with astounding efficiencies of 50% or more. Despite their slower speeds, Stirling engine powered submarines provide more stealth, almost equal endurance, and higher engine efficiencies at a significantly reduced cost.
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    Introduction - Chances are you have never heard of the Stirling Engine, the simple, efficient alternative to the popular Internal Combustion Engine (ICE). Yet it has been around for some time now and has shown numerous benefits and promise in many areas of society. Stirlings are able to operate in any kind of temperature difference, hot or cold, and have been shown to create less pollution and save energy, a major concern with fossil fuel supplies running out. Indeed, with these facts and more, the Stirling Engine appears as something of a modern marvel to engineers. So it seems, at first glance, that the Stirling Engine would be a great alternative across the board to replace the ICE’s that pollute our air and rapidly consume our fuel. But still the ICE is used every day in automobiles, airplanes, lawn mowers, power plants, and other practical applications. The Stirling Engine is not used for any of these. Obviously, there have been some drawbacks to its use in everyday society. So what really are the advantages of the Stirling Engine, particularly over the popular ICE, and why has it not taken a larger role in our society? These questions are what this report intends to answer. The operation, advantages and limitations of the Stirling engine are all addressed so that an appreciation for it and its potential uses can be reached.
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    Abstract - In this project, a simple shock tube was constructed from materials bought at the local plumbing store and found in the fluids laboratory. A shock tube works by raising the pressure on one side of a diaphragm until it ruptures, at which time a shock wave is formed that moves down the remainder of the tube and out the exit. The shock tube made for this experiment was new and needed to be tested many times. It was checked thoroughly for leaks and any other flaws. A suitable diaphragm needed to be found and many different materials were tested for such. After several test runs it was determined from recorded rupture pressures that clear package tape would make the best diaphragm. Due to the length of time it took for the shock tube to be built and tested, shadowgraph imaging that had been planned to take place did not. Calculations of pressure ratios, mach numbers, and velocities of the shock wave and the air behind it were performed.
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    Introduction - Magnetic recording is by far one of the greatest achievements of the past century. It has enabled people to conveniently record on low-cost magnetic tapes or disks, which just as easily as they can be recorded, can be erased and reused numerous times. Believe it or not, the technology for magnetic recording has been around since the turn of the twentieth century when Valdemar Poulsen invented the first recording machine.1 It was not until the German military began employing it in World War II, however, that its use became widespread. Since then the original version has been modified many times to improve both the length of the tape and the quality of the recording.
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    Introduction - Lightning is everywhere in our atmosphere. Scientific estimates say that lightning strikes the earth about one hundred times each second. However, this cloud-to-ground lightning only accounts for about one fifth of the total amount of lightning that takes place each and every day. The majority occurs high above our heads where lightning flashes rapidly from cloud to cloud. Cloud-to-ground lightning, which we see and often measure, contains some phenomenal statistics. The typical downward leader and return stroke (both defined and explored later) travel at an average speed of 243 and 61,400 miles per second respectively. A single stroke of lightning like this can bring an average of 25 coulombs or 156 billion, billion electrons to the earth all at once. The word average is important in this sentence because some recorded flashes have brought close to eight times as much. All of this electrical activity builds up an enormous potential between the thundercloud the ground that is usually somewhere in the vicinity of 10 to 100 million volts. All in all, a single stroke of lightning packs enough power to run a 100-watt light bulb for three months straight. As noted by its speed, lightning is very, very quick. It does not take very long at all, somewhere around a hundredth of a second, for lightning to strike the earth. But so much happens physically in that short time span that it is more than worth our time to investigate exactly how lightning occurs.
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    Introduction - The construction of the ancient Egyptian pyramids is not a matter that can be explained by facts, but must be explained by numerous extensive theories. Of the many theories that are explained in this paper, some provide more factual support than others and are therefore more credible. The many beliefs presented by modern Egyptologists sometimes overlap, but many times do not. Because of the lack of concrete evidence concerning the pyramids' construction, it is impossible to prove any one theory to be correct. It is much more possible and plausible to present some of the more popular and understandable theories on the subject. By generalizing in this way, the process becomes more vague, but it also becomes more realistic. Because it is highly unlikely that any one pyramid was constructed in an identical way to another, all of the theories presented here could have been put to use at some time or another.
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    Introduction - Do a little test for me if you will. Ask your parents how they spent their afternoons after they were let out of elementary school. They will probably tell you about a sandlot baseball game, playing in the creek, or riding their bike around the neighborhood with their friends. And then ask yourself what you remember doing after school. For most of us, we all reluctantly have the same answer: homework. That's because we have grown up in a different generation where what was once considered a supplement to learn-ing in primary schools has since com-pletely taken it over. Some people may find this statement to be extreme, but the truth is, it's not. Elementary school children today are coming home with more and more homework--homework that may be supplementing their immediate academic achievement, but is wearing them down internally in the long run.
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