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WIKIPDF - A TOOL TO HELP SCIENTISTS UNDERSTAND THE LITERATURE OF THE BIOLOGICAL, HEALTH, AND LIFE SCIENCES
Title
WIKIPDF - A TOOL TO HELP SCIENTISTS UNDERSTAND THE LITERATURE OF THE BIOLOGICAL, HEALTH, AND LIFE SCIENCES.
Creator
Calloway, David, Parkinson, Christopher, University of Central Florida
Abstract / Description
Biological sciences literature can be extraordinarily difficult to understand. Papers are commonly filled with terminology unique to a particular sub-discipline. Readers with expertise outside that sub-discipline often have difficulty understanding information the author is trying to convey. The WikiPDF project that is the subject of this thesis helps readers understand the biological sciences literature by automatically generating a customized glossary for each page of any technical paper...
Show moreBiological sciences literature can be extraordinarily difficult to understand. Papers are commonly filled with terminology unique to a particular sub-discipline. Readers with expertise outside that sub-discipline often have difficulty understanding information the author is trying to convey. The WikiPDF project that is the subject of this thesis helps readers understand the biological sciences literature by automatically generating a customized glossary for each page of any technical paper available in Adobe Portable Document Format (PDF) format. WikiPDF relies on the Wikipedia®, an on-line encyclopedia created and supported by a host of volunteers, as a source of definitions used in its glossaries. WikiPDF uses the National Institutes of Health (NIH) Medline/PubMed database of journal papers to organize, index, and locate WikiPDF glossaries. Design and implementation of this project relied exclusively on open-source software, including the Linux operating system, the Apache Tomcat web server, and the MySQL relational database system.
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Date Issued
2006
Identifier
CFE0001084, ucf:46782
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001084
IMPACT OF HURRICANES ON STRUCTURES – A PERFORMANCE BASED ENGINEERING VIEW
Title
IMPACT OF HURRICANES ON STRUCTURES – A PERFORMANCE BASED ENGINEERING VIEW.
Creator
Mishra, Vijay, Mackie, Kevin, University of Central Florida
Abstract / Description
The magnitude of damage caused to the United States (US) coast due to hurricanes has increased significantly in the last decade. During the period 2004-2005, the US experienced seven of the costliest hurricanes in the countryÂÂ's history (NWS TPC-5, 2007) leading to an estimated loss of ~ $158 billion. The present method for predicting hurricane losses, HAZUS (HAZard US), is solely based on hurricane hazard and damage caused to building envelopes only and not to...
Show moreThe magnitude of damage caused to the United States (US) coast due to hurricanes has increased significantly in the last decade. During the period 2004-2005, the US experienced seven of the costliest hurricanes in the countryÂÂ's history (NWS TPC-5, 2007) leading to an estimated loss of ~ $158 billion. The present method for predicting hurricane losses, HAZUS (HAZard US), is solely based on hurricane hazard and damage caused to building envelopes only and not to structural systems (Vickery et al., 2006). This method does not take into account an intermediate step that allows for better damage estimates, which is structural response to the hazards that in turn can be mapped to the damage. The focus of this study was to quantify the uncertainty in response of structures to the hurricane hazards associated with hurricanes from performance based engineering perspective. The study enumerates hazards associated with hurricanes events. The hazards considered can be quantified using a variety of measures, such as wind speed intensities, wave and surge heights. These hazards are quantified in terms of structural loads and are then applied to a structural system. Following that, structural analysis was performed to estimate the response from the structural system for given loads. All the possible responses are measured and they are fitted with suitable probability distribution to estimate the probability of a response. The response measured then can be used to understand the performance of a given structure under the various hurricane loads. Dynamic vs. static analysis was performed and results were compared. This will answer a few questions like, if there is any need to do both static and dynamic analysis and how hurricane loads affect the structural material models. This being an exploratory study, available resources, research, and models were used. For generation of annual or extreme values of hazard, various available wind speed, storm surge, and wave height models were studied and evaluated. The wind field model by Batts et al. (1980) was selected for generation of annual wind speed data. For calculation of maximum storm surge height, the Sea, Lake Overland Surges from Hurricane (SLOSH, Jelesnianski et al., 1992) program was used. Wave data was acquired from a National Oceanic and Atmospheric Administration (NOAA) database. The (extreme or annual) wind speed, surge height, and wave height generated were then fitted by suitable probability distributions to find the realizations of hazards and their probabilities. The distribution properties were calculated, correlations between the data were established, and a joint probability distribution function (PDF) of the parameters (wind speed, wave height, and storm surge) was generated. Once the joint distribution of extreme loads was established, the next step was to measure the dynamic response of the structural system to these hazards. To measure the structural response, a finite element model of three-story concrete frame were constructed. Time histories of wind load were generated from wind net pressure coefficients recorded in a wind tunnel test (Main and Fritz, 2006). Wave load time histories were generated using laboratory basin test (HawkeÂÂ's et al., 1993) wave height time history data and were converted into wave loads using BernoulliÂÂ's equation. Surge height was treated as a hydrostatic load in this analysis. These load time histories were then applied to the finite element model and response was measured. Response of the structural system was measured in terms of the mean and maximum displacements recorded at specific nodes of model. Response was calculated for loads having constant mean wind speed and surge/wave and different time histories. The dominant frequency in the wind load time histories was closer to the natural frequency of the structural model used than the dominant frequency in the wave height time histories. Trends in the response for various combinations of mean wind speed, wave height, and surge heights were analyzed. It was observed that responses are amplified with increase in the mean wind speed. Less response was measured for change in mean surge/wave height as the tributary area for wave forces was less compared to wind force. No increase in dynamic amplification factor was observed for increase in force time histories case.
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Date Issued
2010
Identifier
CFE0003162, ucf:48612
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003162
FADE STATISTICS FOR A LASERCOM SYSTEM AND THE JOINT PDF OF A GAMMA-GAMMA DISTRIBUTED IRRADIANCE AND ITS TIME DERIVATIVE
Title
FADE STATISTICS FOR A LASERCOM SYSTEM AND THE JOINT PDF OF A GAMMA-GAMMA DISTRIBUTED IRRADIANCE AND ITS TIME DERIVATIVE.
Creator
Stromqvist Vetelino, Frida, Young, Cynthia, University of Central Florida
Abstract / Description
The performance of lasercom systems operating in the atmosphere is reduced by optical turbulence, which causes irradiance fluctuations in the received signal. The result is a randomly fading signal. Fade statistics for lasercom systems are determined from the probability density function (PDF) of the irradiance fluctuations. The expected number of fades per second and their mean fade time require the joint PDF of the fluctuating irradiance and its time derivative. Theoretical integral...
Show moreThe performance of lasercom systems operating in the atmosphere is reduced by optical turbulence, which causes irradiance fluctuations in the received signal. The result is a randomly fading signal. Fade statistics for lasercom systems are determined from the probability density function (PDF) of the irradiance fluctuations. The expected number of fades per second and their mean fade time require the joint PDF of the fluctuating irradiance and its time derivative. Theoretical integral expressions, as well as closed form, analytical approximations, were developed for the joint PDF of a gamma-gamma distributed irradiance and its time derivative, and the corresponding expression for the expected number of fades per second. The new approximation for the conditional PDF of the time derivative of a gamma-gamma irradiance is a zero mean Gaussian distribution, with a complicated irradiance depending variance. Fade statistics obtained from experimental data were compared to theoretical predictions based on the lognormal and gamma-gamma distributions. A Gaussian beam wave was propagated through the atmosphere along a horizontal path, near ground, in the moderate-to-strong optical turbulence. To characterize the propagation path, a new method that infers atmospheric propagation parameters was developed. Scintillation theory combined with a numerical scheme was used to infer the structure constant, Cn2, the inner scale and the outer scale from the optical measurements. The inferred parameters were used in calculations for the theoretical PDFs. It was found that fade predictions made by the gamma-gamma and lognormal distributions provide an upper and lower bound, respectively, for the probability of fade and the number of fades per second for irradiance data collected in the moderate-to-strong fluctuation regime. Aperture averaging effects on the PDF of the irradiance fluctuations were investigated by comparing the irradiance distributions for the three receiver apertures at two different values of the structure parameter and, hence, different values of the coherence radius. For the moderate-to-strong fluctuation regime, the gamma-gamma distribution provides a good fit to the irradiance fluctuations collected by finite-sized apertures that are significantly smaller than the coherence radius. For apertures larger than or equal to the coherence radius, the irradiance fluctuations appear to be lognormally distributed.
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Date Issued
2006
Identifier
CFE0001440, ucf:47069
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0001440
THE PDF OF IRRADIANCE FOR A FREE-SPACE OPTICAL COMMUNICATIONS CHANNEL: A PHYSICS BASED MODEL
Title
THE PDF OF IRRADIANCE FOR A FREE-SPACE OPTICAL COMMUNICATIONS CHANNEL: A PHYSICS BASED MODEL.
Creator
Wayne, David, Phillips, Ronald, University of Central Florida
Abstract / Description
An accurate PDF of irradiance for a FSO channel is important when designing a laser radar, active laser imaging, or a communications system to operate over the channel. Parameters such as detector threshold level, probability of detection, mean fade time, number of fades, BER, and SNR are derived from the PDF and determine the design constraints of the receiver, transmitter, and corresponding electronics. Current PDF models of irradiance, such as the Gamma-Gamma, do not fully capture the...
Show moreAn accurate PDF of irradiance for a FSO channel is important when designing a laser radar, active laser imaging, or a communications system to operate over the channel. Parameters such as detector threshold level, probability of detection, mean fade time, number of fades, BER, and SNR are derived from the PDF and determine the design constraints of the receiver, transmitter, and corresponding electronics. Current PDF models of irradiance, such as the Gamma-Gamma, do not fully capture the effect of aperture averaging; a reduction in scintillation as the diameter of the collecting optic is increased. The Gamma-Gamma PDF of irradiance is an attractive solution because the parameters of the distribution are derived strictly from atmospheric turbulence parameters; propagation path length, Cn2, l0, and L0. This dissertation describes a heuristic physics-based modeling technique to develop a new PDF of irradiance based upon the optical field. The goal of the new PDF is three-fold: capture the physics of the turbulent atmosphere, better describe aperture averaging effects, and relate parameters of the new model to measurable atmospheric parameters. The modeling decomposes the propagating electromagnetic field into a sum of independent random-amplitude spatial plane waves using an approximation to the Karhunen-Loeve expansion. The scattering effects of the turbulence along the propagation path define the random-amplitude of each component of the expansion. The resulting PDF of irradiance is a double finite sum containing a Bessel function. The newly developed PDF is a generalization of the Gamma-Gamma PDF, and reduces to such in the limit. An experiment was setup and performed to measure the PDF of irradiance for several receiver aperture sizes under moderate to strong turbulence conditions. The propagation path was instrumented with scintillometers and anemometers to characterize the turbulence conditions. The newly developed PDF model and the GG model were compared to histograms of the experimental data. The new PDF model was typically able to match the data as well or better than the GG model under conditions of moderate aperture averaging. The GG model fit the data better than the new PDF under conditions of significant aperture averaging. Due to a limiting scintillation index value of 3, the new PDF was not compared to the GG for point apertures under strong turbulence; a regime where the GG is known to fit data well.
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Date Issued
2010
Identifier
CFE0003209, ucf:48576
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0003209
ANALYSIS OF TIME SYNCHRONIZATION ERRORS IN HIGH DATA RATE ULTRAWIDEBAND ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING DATA LINKS
Title
ANALYSIS OF TIME SYNCHRONIZATION ERRORS IN HIGH DATA RATE ULTRAWIDEBAND ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING DATA LINKS.
Creator
Bates, Lakesha, Jones, W. Linwood, University of Central Florida
Abstract / Description
Emerging Ultra Wideband (UWB) Orthogonal Frequency Division Multiplexing (OFDM) systems hold the promise of delivering wireless data at high speeds, exceeding hundreds of megabits per second over typical distances of 10 meters or less. The purpose of this Thesis is to estimate the timing accuracies required with such systems in order to achieve Bit Error Rates (BER) of the order of magnitude of 10-12 and thereby avoid overloading the correction of irreducible errors due to misaligned timing...
Show moreEmerging Ultra Wideband (UWB) Orthogonal Frequency Division Multiplexing (OFDM) systems hold the promise of delivering wireless data at high speeds, exceeding hundreds of megabits per second over typical distances of 10 meters or less. The purpose of this Thesis is to estimate the timing accuracies required with such systems in order to achieve Bit Error Rates (BER) of the order of magnitude of 10-12 and thereby avoid overloading the correction of irreducible errors due to misaligned timing errors to a small absolute number of bits in error in real-time relative to a data rate of hundreds of megabits per second. Our research approach involves managing bit error rates through identifying maximum timing synchronization errors. Thus, it became our research goal to determine the timing accuracies required to avoid operation of communication systems within the asymptotic region of BER flaring at low BERs in the resultant BER curves. We propose pushing physical layer bit error rates to below 10-12 before using forward error correction (FEC) codes. This way, the maximum reserve is maintained for the FEC hardware to correct for burst as well as recurring bit errors due to corrupt bits caused by other than timing synchronization errors.
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Date Issued
2004
Identifier
CFE0000197, ucf:46173
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0000197
Exploring the Innovation Environment within the Systems Engineering Context of a Defense Organization: A Preliminary Framework
Title
Exploring the Innovation Environment within the Systems Engineering Context of a Defense Organization: A Preliminary Framework.
Creator
Odeh, Khaled, Rabelo, Luis, Elshennawy, Ahmad, Lee, Gene, Karwowski, Waldemar, Uddin, Nizam, University of Central Florida
Abstract / Description
Innovation may involve the introduction of ideas for designing or producing new products, or introducing improvements to products, processes, services or any other aspect of an organization to the market place. A major element for measuring organizational strength is its perception of innovation and the ability of the organization to build on and sustain such strength. While there is no shortage of research and study materials on innovation, there is, however, a shortage of thorough and...
Show moreInnovation may involve the introduction of ideas for designing or producing new products, or introducing improvements to products, processes, services or any other aspect of an organization to the market place. A major element for measuring organizational strength is its perception of innovation and the ability of the organization to build on and sustain such strength. While there is no shortage of research and study materials on innovation, there is, however, a shortage of thorough and realistic analysis of the intersection of innovation management, and measurement of innovation within the systems engineering context of defense organizations. In addition, while most research studies seem to adopt strictly quantitative innovation factors in determining innovation success and performance, they seem to have overlooked the qualitative side of it. An objective of this research study is to address the need for exploring the innovation environment within the systems engineering context of a defense organization. In addition, the research presents a new model for exploring innovation factors within the examined environment, using both quantitative and qualitative factors. The research uses a number of data collection instruments that include a survey construct to gather quantitative and qualitative data. The study identified significant factors that could be used to properly determine innovation within the systems engineering context of defense organizations using traditional statistics and data mining modeling. New indicators such as security and organizational leadership are discovered as important to define, monitor, and assess the innovation of the defense industry within the context of systems engineering.
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Date Issued
2013
Identifier
CFE0004903, ucf:49643
Format
Document (PDF)
PURL
http://purl.flvc.org/ucf/fd/CFE0004903