Current Search: Structural (x)
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- Title
- High-Performance Composable Transactional Data Structures.
- Creator
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Zhang, Deli, Dechev, Damian, Leavens, Gary, Zou, Changchun, Lin, Mingjie, University of Central Florida
- Abstract / Description
-
Exploiting the parallelism in multiprocessor systems is a major challenge in the post ``power wall'' era. Programming for multicore demands a change in the way we design and use fundamental data structures. Concurrent data structures allow scalable and thread-safe accesses to shared data. They provide operations that appear to take effect atomically when invoked individually.A main obstacle to the practical use of concurrent data structures is their inability to support composable operations,...
Show moreExploiting the parallelism in multiprocessor systems is a major challenge in the post ``power wall'' era. Programming for multicore demands a change in the way we design and use fundamental data structures. Concurrent data structures allow scalable and thread-safe accesses to shared data. They provide operations that appear to take effect atomically when invoked individually.A main obstacle to the practical use of concurrent data structures is their inability to support composable operations, i.e., to execute multiple operations atomically in a transactional manner. The problem stems from the inability of concurrent data structure to ensure atomicity of transactions composed from operations on a single or multiple data structures instances. This greatly hinders software reuse because users can only invoke data structure operations in a limited number of ways.Existing solutions, such as software transactional memory (STM) and transactional boosting, manage transaction synchronization in an external layer separated from the data structure's own thread-level concurrency control. Although this reduces programming effort, it leads to significant overhead associated with additional synchronization and the need to rollback aborted transactions. In this dissertation, I address the practicality and efficiency concerns by designing, implementing, and evaluating high-performance transactional data structures that facilitate the development of future highly concurrent software systems.Firstly, I present two methodologies for implementing high-performance transactional data structures based on existing concurrent data structures using either lock-based or lock-free synchronizations. For lock-based data structures, the idea is to treat data accessed by multiple operations as resources. The challenge is for each thread to acquire exclusive access to desired resources while preventing deadlock or starvation. Existing locking strategies, like two-phase locking and resource hierarchy, suffer from performance degradation under heavy contention, while lacking a desirable fairness guarantee. To overcome these issues, I introduce a scalable lock algorithm for shared-memory multiprocessors addressing the resource allocation problem. It is the first multi-resource lock algorithm that guarantees the strongest first-in, first-out (FIFO) fairness. For lock-free data structures, I present a methodology for transforming them into high-performance lock-free transactional data structures without revamping the data structures' original synchronization design. My approach leverages the semantic knowledge of the data structure to eliminate the overhead of false conflicts and rollbacks.Secondly, I apply the proposed methodologies and present a suite of novel transactional search data structures in the form of an open source library. This is interesting not only because the fundamental importance of search data structures in computer science and their wide use in real world programs, but also because it demonstrate the implementation issues that arise when using the methodologies I have developed. This library is not only a compilation of a large number of fundamental data structures for multiprocessor applications, but also a framework for enabling composable transactions, and moreover, an infrastructure for continuous integration of new data structures. By taking such a top-down approach, I am able to identify and consider the interplay of data structure interface operations as a whole, which allows for scrutinizing their commutativity rules and hence opens up possibilities for design optimizations.Lastly, I evaluate the throughput of the proposed data structures using transactions with randomly generated operations on two difference hardware systems. To ensure the strongest possible competition, I chose the best performing alternatives from state-of-the-art locking protocols and transactional memory systems in the literature. The results show that it is straightforward to build efficient transactional data structures when using my multi-resource lock as a drop-in replacement for transactional boosted data structures. Furthermore, this work shows that it is possible to build efficient lock-free transactional data structures with all perceived benefits of lock-freedom and with performance far better than generic transactional memory systems.
Show less - Date Issued
- 2016
- Identifier
- CFE0006428, ucf:51453
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006428
- Title
- Cafeteria Culture: An Anthropological Approach to Lunchtime in a Central Florida Elementary School.
- Creator
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Herrington, Emily, Matejowsky, Ty, Williams, Lana, Geiger, Vance, University of Central Florida
- Abstract / Description
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Public school cafeterias are used by nearly 51 million children (ages 4-17) in the United States every day. With over 40% of the approximately 73 million children (ages 0-17) participating in the National School Lunch Program (NSLP), public school lunches carry resounding nutritional, social, and educational significance for their consumers. This fact, coupled with frequent media attention to school lunch food, notwithstanding, a notable lack of social scientific engagement with both students...
Show morePublic school cafeterias are used by nearly 51 million children (ages 4-17) in the United States every day. With over 40% of the approximately 73 million children (ages 0-17) participating in the National School Lunch Program (NSLP), public school lunches carry resounding nutritional, social, and educational significance for their consumers. This fact, coupled with frequent media attention to school lunch food, notwithstanding, a notable lack of social scientific engagement with both students' perspectives and NSLP operators persists. Divided into two studies, this research utilizes ethnographic methods to explore students' lunchtime experiences within a Central Florida public elementary school cafeteria. Both works are grounded in information collected from 22 semi-structured and unstructured interviews with students, parents, cafeteria workers, school faculty, and a county official while also participating in a one-month lunchtime observation period in Spring 2017. The first study utilizes ethnographic methods to investigate students' food selection, social practices, and mealtime behaviors within the cafeteria. In this work, I argue that student's preferences are most often informed by taste and familiarity, though both age and personal belief systems strongly outline students' experiences. In the second study, I focus on the top-down priorities of nutrition, food production, and student feedback that guide how institutions construct lunch menus for elementary students. Specifically, I investigate what role public institutions play in forming elementary school students' understandings of food and expectations for mealtimes. Synthesizing findings from both studies, I assess how social, economic, and industry pressures are tangible within local cafeteria and governmental contexts. This research contributes to academic scholarship and public policy regarding childhood nutrition in institutionalized settings and advocates for the inclusion of elementary-aged children as important social actors in their call for increased and dietarily-inclusive food options.
Show less - Date Issued
- 2017
- Identifier
- CFE0006882, ucf:51732
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006882
- Title
- A Comparison of Concurrent Correctness Criteria for Shared Memory Based Data Structure.
- Creator
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Bhattacharya, Dipanjan, Dechev, Damian, Leavens, Gary, Bassiouni, Mostafa, University of Central Florida
- Abstract / Description
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Developing concurrent algorithms requires safety and liveness to be defined in order to understand their proper behavior. Safety refers to the correctness criteria while liveness is the progress guarantee. Nowadays there are a variety of correctness conditions for concurrent objects. The way these correctness conditions differ and the various trade-offs they present with respect to performance, usability, and progress guarantees is poorly understood. This presents a daunting task for the...
Show moreDeveloping concurrent algorithms requires safety and liveness to be defined in order to understand their proper behavior. Safety refers to the correctness criteria while liveness is the progress guarantee. Nowadays there are a variety of correctness conditions for concurrent objects. The way these correctness conditions differ and the various trade-offs they present with respect to performance, usability, and progress guarantees is poorly understood. This presents a daunting task for the developers and users of such concurrent algorithms who are trying to better understand the correctness of their code and the various trade-offs associated with their design choices and use. The purpose of this study is to explore the set of known correctness conditions for concurrent objects, find their correlations and categorize them, and provide insights regarding their implications with respect to performance and usability. In this thesis, a comparative study of Linearizability, Sequential Consistency, Quiescent Consistency and Quasi Linearizability will be presented using data structures like FIFO Queues, Stacks, and Priority Queues, and with a case study for performance of these implementations using different correctness criteria.
Show less - Date Issued
- 2016
- Identifier
- CFE0006263, ucf:51046
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006263
- Title
- The relationship among post-traumatic growth, religious commitment, and optimism in adult Liberian former refugees and internally displaced persons traumatized by war-related events.
- Creator
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Acquaye, Hannah, Jones, Dayle, Robinson, Edward, Van Horn, Stacy, Sivo, Stephen, University of Central Florida
- Abstract / Description
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One of the myriad consequences of war is displacement and refugee-ism. People become refugees when they no longer feel safe in their country of origin. Before, during, and after the journey towards safety, refugees and internally displaced persons (IDPs) endure several challenging circumstances which stretch their normal abilities to cope. In their efforts to cope, these people report several mental health challenges like sleeplessness, hypervigilance, anxiety, and depression. The reported...
Show moreOne of the myriad consequences of war is displacement and refugee-ism. People become refugees when they no longer feel safe in their country of origin. Before, during, and after the journey towards safety, refugees and internally displaced persons (IDPs) endure several challenging circumstances which stretch their normal abilities to cope. In their efforts to cope, these people report several mental health challenges like sleeplessness, hypervigilance, anxiety, and depression. The reported mental health challenges are normal in this population; however, when they persist, they result in posttraumatic stress disorder. Surprisingly, some also report obtaining psychological growth due to their challenging circumstances. To examine the interplay of posttraumatic stress disorder and psychological growth in this population, the study was grounded on the cognitive theory of trauma and the broaden-and-build theory of positive emotions. Thus, the relationship among posttraumatic growth, religious commitment, and optimism within adult Liberian former refugees and IDPs traumatized by war-related events became the focus of the investigation. The grounding theories provided four hypotheses that explored the relationship among the constructs, as well as seven exploratory research questions that identified differences among participants. Through purposeful and snowball sampling methods, five hundred participants were selected as the sample; 444 returned the study package. Participants were adult Liberian former refugees and IDPs who could read and understand English at the 8th grade level, and who lived in Monrovia. Participants completed six instruments (-) the Posttraumatic Growth Inventory, the Religious Commitment Inventory, the Revised Life Orientation Test, the War Trauma Screening Index, the Posttraumatic Stress Disorder Checklist for DSM-5, and demographic questionnaire. Results of the study indicated that there was a statistically significant correlation between impact of war-related events and posttraumatic stress disorder, with alterations in arousal and reactivity obtaining the strongest correlation. However, the presence of posttraumatic stress disorder for the Liberian sample could be attributed to the recent reaction to the Ebola virus which re-traumatized adult Liberian former refugees and IDPs. Furthermore, there was a statistically significant relationship between all factors of posttraumatic stress disorder and all factors of posttraumatic growth. The relationship between factors of religious commitment and factors of posttraumatic stress disorder was statistically significant for some posttraumatic stress disorder factors and not significant for others. Similarly, relationship between optimism and posttraumatic stress disorder was statistically significant for some and not significant for others. Finally, a structural equation model was conducted to identify latent variables affecting the relationship. Results indicated, as per the hypothesized model, that war events predicted trauma, which in turn predicted posttraumatic growth. However, even though religiousness and optimism could each predict posttraumatic growth, optimism, more than religiousness provided errors that co-varied with errors of trauma, indicating that with the presence of optimism, a person could move from trauma towards growth. Review of related literature situated the current study in the mental health discourse, especially in providing a voice for mental health on the African continent. Detailed methodology was provided, as were results of findings. Finally, summary, conclusions, and recommendations were provided for both mental health workers, counselor educators, and researchers.
Show less - Date Issued
- 2016
- Identifier
- CFE0006241, ucf:51077
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006241
- Title
- Determinants of Terrorist Target Selection: A Quantitative Analysis.
- Creator
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Haywood, Taylor, Handberg, Roger, Dolan, Thomas, Boutton, Andrew, Vasquez, Joseph, University of Central Florida
- Abstract / Description
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Existing research on the subject of terrorism is vast, spanning causes of terrorism, the membership of terrorist groups, types of terrorist attacks, and more. One area of terrorism research, though, has received only limited consideration: terrorist target selection. What research does exist explains target selection almost exclusively as a function of ideology (Asal et al. 2009, 270 and 274; Drake 1998b, 54-56 and 58). However, such a limited causal focus obscures other possible, and...
Show moreExisting research on the subject of terrorism is vast, spanning causes of terrorism, the membership of terrorist groups, types of terrorist attacks, and more. One area of terrorism research, though, has received only limited consideration: terrorist target selection. What research does exist explains target selection almost exclusively as a function of ideology (Asal et al. 2009, 270 and 274; Drake 1998b, 54-56 and 58). However, such a limited causal focus obscures other possible, and probable, explanations of terrorist target selection. This paper proposes an alternative explanation of terrorist target selection that includes ideological and terrorist group capability variables, as well as a variable measuring the security levels in the geographic areas in which terrorist attacks take place. A research design employing multiple ordinary least squares regression is utilized. The findings demonstrate the importance of the independent variables, as well as the significance of the effects of the two-way and three-way interactions of variables from the three categories. Furthermore, the multiple regression models explain a greater percentage of the effects of the independent variables on the percentage of attacks against civilian targets when the three-way interaction variable is included than when this interaction variable is not included. From these findings, two primary policy implications are derived.
Show less - Date Issued
- 2017
- Identifier
- CFE0006744, ucf:51853
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006744
- Title
- Structural Health Monitoring using Novel Sensing Technologies and Data Analysis Methods.
- Creator
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Malekzadeh, Seyedmasoud, Catbas, Fikret, Yun, Hae-Bum, Tatari, Mehmet, Moslehy, Faissal, Gul, Mustafa, University of Central Florida
- Abstract / Description
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The main objective of this research is to explore, investigate and develop the new data analysis techniques along with novel sensing technologies for structural health monitoring applications. The study has three main parts. First, a systematic comparative evaluation of some of the most common and promising methods is carried out along with a combined method proposed in this study for mitigating drawbacks of some of the techniques. Secondly, non-parametric methods are evaluated on a real life...
Show moreThe main objective of this research is to explore, investigate and develop the new data analysis techniques along with novel sensing technologies for structural health monitoring applications. The study has three main parts. First, a systematic comparative evaluation of some of the most common and promising methods is carried out along with a combined method proposed in this study for mitigating drawbacks of some of the techniques. Secondly, non-parametric methods are evaluated on a real life movable bridge. Finally, a hybrid approach for non-parametric and parametric method is proposed and demonstrated for more in depth understanding of the structural performance. In view of that, it is shown in the literature that four efficient non-parametric algorithms including, Cross Correlation Analysis (CCA), Robust Regression Analysis (RRA), Moving Cross Correlation Analysis (MCCA) and Moving Principal Component Analysis (MPCA) have shown promise with respect to the conducted numerical studies. As a result, these methods are selected for further systematic and comparative evaluation using experimental data. A comprehensive experimental test is designed utilizing Fiber Bragg Grating (FBG) sensors simulating some of the most critical and common damage scenarios on a unique experimental structure in the laboratory. Subsequently the SHM data, that is generated and collected under different damage scenarios, are employed for comparative study of the selected techniques based on critical criteria such as detectability, time to detection, effect of noise, computational time and size of the window. The observations indicate that while MPCA has the best detectability, it does not perform very reliable results in terms of time to detection. As a result, a machine-learning based algorithm is explored that not only reduces the associated delay with MPCA but further improves the detectability performance. Accordingly, the MPCA and MCCA are combined to introduce an improved algorithm named MPCA-CCA. The new algorithm is evaluated through both experimental and real-life studies. It is realized that while the methods identified above have failed to detect the simulated damage on a movable bridge, the MPCA-CCA algorithm successfully identified the induced damage. An investigative study for automated data processing method is developed using non-parametric data analysis methods for real-time condition maintenance monitoring of critical mechanical components of a movable bridge. A maintenance condition index is defined for identifying and tracking the critical maintenance issues. The efficiency of the maintenance condition index is then investigated and demonstrated against some of the corresponding maintenance problems that have been visually and independently identified for the bridge.Finally, a hybrid data interpretation framework is designed taking advantage of the benefits of both parametric and non-parametric approaches and mitigating their shortcomings. The proposed approach can then be employed not only to detect the damage but also to assess the identified abnormal behavior. This approach is also employed for optimized sensor number and locations on the structure.
Show less - Date Issued
- 2014
- Identifier
- CFE0005207, ucf:50648
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005207
- Title
- The Response of American Police Agencies to Digital Evidence.
- Creator
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Yesilyurt, Hamdi, Wan, Thomas, Potter, Roberto, Applegate, Brandon, Lang, Sheau-Dong, University of Central Florida
- Abstract / Description
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Little is known about the variation in digital forensics practice in the United States as adopted by large local police agencies. This study investigated how environmental constraints, contextual factors, organizational complexity, and organizational control relate to the adoption of digital forensics practice. This study integrated 3 theoretical perspectives in organizational studies to guide the analysis of the relations: institutional theory, contingency theory, and adoption-of-innovation...
Show moreLittle is known about the variation in digital forensics practice in the United States as adopted by large local police agencies. This study investigated how environmental constraints, contextual factors, organizational complexity, and organizational control relate to the adoption of digital forensics practice. This study integrated 3 theoretical perspectives in organizational studies to guide the analysis of the relations: institutional theory, contingency theory, and adoption-of-innovation theory. Institutional theory was used to analyze the impact of environmental constraints on the adoption of innovation, and contingency theory was used to examine the impacts of organizational control on the adoption of innovation. Adoption of innovation theory was employed to describe the degree to which digital forensics practice has been adopted by large municipal police agencies having 100 or more sworn police officers.The data set was assembled primarily by using Law Enforcement Management and Administrative Statistics (LEMAS) 2003 and 1999. Dr. Edward Maguire`s survey was used to obtain 1 variable. The joining up of the data set to construct the sample resulted in 345 large local police agencies. The descriptive results on the degree of adoption of digital forensics practice indicate that 37.7% of large local police agencies have dedicated personnel to address digital evidence, 32.8% of police agencies address digital evidence but do not have dedicated personnel, and only 24.3% of police agencies have a specialized unit with full-time personnel to address digital evidence. About 5% of local police agencies do nothing to address digital evidence in any circumstance. These descriptive statistics indicate that digital evidence is a matter of concern for most large local police agencies and that they respond to varying degrees to digital evidence at the organizational level. Agencies that have not adopted digital forensics practice are in the minority. The structural equation model was used to test the hypothesized relations, easing the rigorous analysis of relations between latent constructs and several indicator variables. Environmental constraints have the largest impact on the adoption of innovation, exerting a positive influence. No statistically significant relation was found between organizational control and adoption of digital forensic practice. Contextual factors (task scope and personnel size) positively influence the adoption of digital forensics. Structural control factors, including administrative weight and formalization, have no significant influence on the adoption of innovation. The conclusions of the study are as follows. Police agencies adopt digital forensics practice primarily by relying on environmental constraints. Police agencies exposed to higher environmental constraints are more frequently expected to adopt digital forensics practice. Because organizational control of police agencies is not significantly related to digital forensics practice adoption, police agencies do not take their organizational control extensively into consideration when they consider adopting digital forensics practice. The positive influence of task scope and size on digital forensics practice adoption was expected. The extent of task scope and the number of personnel indicate a higher capacity for police agencies to adopt digital forensics practice. Administrative weight and formalization do not influence the adoption of digital forensics practice. Therefore, structural control and coordination are not important for large local police agencies to adopt digital forensics practice.The results of the study indicate that the adoption of digital forensics practice is based primarily on environmental constraints. Therefore, more drastic impacts on digital forensics practice should be expected from local police agencies' environments than from internal organizational factors. Researchers investigating the influence of various factors on the adoption of digital forensics practice should further examine environmental variables. The unexpected results concerning the impact of administrative weight and formalization should be researched with broader considerations.
Show less - Date Issued
- 2011
- Identifier
- CFE0004181, ucf:49081
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004181
- Title
- Structural Identification through Monitoring, Modeling and Predictive Analysis under Uncertainty.
- Creator
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Gokce, Hasan, Catbas, Fikret, Chopra, Manoj, Mackie, Kevin, Yun, Hae-Bum, DeMara, Ronald, University of Central Florida
- Abstract / Description
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Bridges are critical components of highway networks, which provide mobility and economical vitality to a nation. Ensuring the safety and regular operation as well as accurate structural assessment of bridges is essential. Structural Identification (St-Id) can be utilized for better assessment of structures by integrating experimental and analytical technologies in support of decision-making. St-Id is defined as creating parametric or nonparametric models to characterize structural behavior...
Show moreBridges are critical components of highway networks, which provide mobility and economical vitality to a nation. Ensuring the safety and regular operation as well as accurate structural assessment of bridges is essential. Structural Identification (St-Id) can be utilized for better assessment of structures by integrating experimental and analytical technologies in support of decision-making. St-Id is defined as creating parametric or nonparametric models to characterize structural behavior based on structural health monitoring (SHM) data. In a recent study by the ASCE St-Id Committee, St-Id framework is given in six steps, including modeling, experimentation and ultimately decision making for estimating the performance and vulnerability of structural systems reliably through the improved simulations using monitoring data. In some St-Id applications, there can be challenges and considerations related to this six-step framework. For instance not all of the steps can be employed; thereby a subset of the six steps can be adapted for some cases based on the various limitations. In addition, each step has its own characteristics, challenges, and uncertainties due to the considerations such as time varying nature of civil structures, modeling and measurements. It is often discussed that even a calibrated model has limitations in fully representing an existing structure; therefore, a family of models may be well suited to represent the structure's response and performance in a probabilistic manner.The principle objective of this dissertation is to investigate nonparametric and parametric St-Id approaches by considering uncertainties coming from different sources to better assess the structural condition for decision making. In the first part of the dissertation, a nonparametric St-Id approach is employed without the use of an analytical model. The new methodology, which is successfully demonstrated on both lab and real-life structures, can identify and locate the damage by tracking correlation coefficients between strain time histories and can locate the damage from the generated correlation matrices of different strain time histories. This methodology is found to be load independent, computationally efficient, easy to use, especially for handling large amounts of monitoring data, and capable of identifying the effectiveness of the maintenance. In the second part, a parametric St-Id approach is introduced by developing a family of models using Monte Carlo simulations and finite element analyses to explore the uncertainty effects on performance predictions in terms of load rating and structural reliability. The family of models is developed from a parent model, which is calibrated using monitoring data. In this dissertation, the calibration is carried out using artificial neural networks (ANNs) and the approach and results are demonstrated on a laboratory structure and a real-life movable bridge, where predictive analyses are carried out for performance decrease due to deterioration, damage, and traffic increase over time. In addition, a long-span bridge is investigated using the same approach when the bridge is retrofitted. The family of models for these structures is employed to determine the component and system reliability, as well as the load rating, with a distribution that incorporates various uncertainties that were defined and characterized. It is observed that the uncertainties play a considerable role even when compared to calibrated model-based predictions for reliability and load rating, especially when the structure is complex, deteriorated and aged, and subjected to variable environmental and operational conditions. It is recommended that a family-of-models approach is suitable for structures that have less redundancy, high operational importance, are deteriorated, and are performing under close capacity and demand levels.
Show less - Date Issued
- 2012
- Identifier
- CFE0004232, ucf:48997
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004232
- Title
- APPLICATIONS OF AIRBORNE AND PORTABLE LIDAR IN THE STRUCTURAL DETERMINATION, MANAGEMENT, AND CONSERVATION OF SOUTHEASTERN U.S. PINE FORESTS.
- Creator
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Listopad, Claudia, Weishampel, John, University of Central Florida
- Abstract / Description
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Active remote sensing techniques, such as Light Detection and Ranging (LiDAR), have transformed the field of forestry and natural resource management in the last decade. Intensive assessments of forest resources and detailed structural assessments can now be accomplished faster and at multiple landscape scales. The ecological applications of having this valuable information at-hand are still only being developed. This work explores the use of two active remote sensing techniques, airborne and...
Show moreActive remote sensing techniques, such as Light Detection and Ranging (LiDAR), have transformed the field of forestry and natural resource management in the last decade. Intensive assessments of forest resources and detailed structural assessments can now be accomplished faster and at multiple landscape scales. The ecological applications of having this valuable information at-hand are still only being developed. This work explores the use of two active remote sensing techniques, airborne and portable LiDAR for forestry applications in a rapidly changing landscape, Southeastern Coastal Pine woodlands. Understanding the strengths and weaknesses of airborne and portable LiDAR, the tools used to extract structural information, and how to apply these to managing fire regimes are key to conserving unique upland pine ecosystems. Measuring habitat structure remotely and predicting habitat suitability through modeling will allow for the management of specific species of interest, such as threatened and endangered species. Chapter one focuses on the estimation of canopy cover and height measures across a variety of conditions of secondary upland pine and hardwood forests at Tall Timbers Research Station, FL. This study is unique since it uses two independent high resolution small-footprint LiDAR datasets (years 2002 and 2008) and extensive field plot and transect sampling for validation. Chapter One explores different tools available for metric derivation and tree extraction from discrete return airborne LiDAR data, highlighting strengths and weaknesses of each. Field and LiDAR datasets yielded better correlations for stand level comparisons, especially in canopy cover and mean height data extracted. Individual tree crown extraction from airborne LiDAR data significantly under-reported the total number of trees reported in the field datasets using either Fusion/LVD and LiDAR Analyst (Overwatch). Chapter two evaluates stand structure at the site of one of the longest running fire ecology studies in the US, located at Tall Timbers Research Station (TTRS) in the southeastern U.S. Small footprint high resolution discrete return LiDAR was used to provide an understanding of the impact of multiple disturbance regimes on forest structure, especially on the 3-dimensional spatial arrangement of multiple structural elements and structural diversity indices. LiDAR data provided sensitive detection of structural metrics, diversity, and fine-scale vertical changes in the understory and mid-canopy structure. Canopy cover and diversity indices were shown to be statistically higher in fire suppressed and less frequently burned plots than in 1- and 2-year fire interval treated plots, which is in general agreement with the increase from 2- to 3-year fire return interval being considered an "ecological threshold" for these systems (Masters et al. 2005). The results from this study highlight the value of the use of LiDAR in evaluating disturbance impacts on the three-dimensional structure of pine forest systems, particularly over large landscapes. Chapter three uses an affordable portable LiDAR system, first presented by Parker et al. (2004) and further modified for extra portability, to provide an understanding of structural differences between old-growth and secondary-growth forests in the Red Hills area of southwestern Georgia and North Florida. It also provides insight into the strengths and weaknesses in structural determination of ground-based portable systems in contrast to airborne LiDAR systems. Structural plot metrics obtained from airborne and portable LiDAR systems presented some similarities (i.e. canopy cover), but distinct differences appeared when measuring canopy heights (maximum and mean heights) using these different methods. Both the airborne and portable systems were able to provide gap detection and canopy cover estimation at the plot level. The portable system, when compared to the airborne LiDAR sensor, provides an underestimation of canopy cover in open forest systems (<50% canopy cover), but is more sensitive in detection of cover in hardwood woodland plots (>60% canopy cover). The strength of the portable LiDAR system lies in the detection of 3-dimensional fine structural changes (i.e. recruitment, encroachment) and with higher sensitivity in detecting lower canopy levels, often missed by airborne systems. Chapter four addresses a very promising application for fine-scale airborne LiDAR data, the creation of habitat suitability models for species of management and conservation concerns. This Chapter uses fine scale LiDAR metrics, such as canopy cover at various height strata, canopy height information, and a measure of horizontal vegetation distribution (clumped versus dispersed) to model the preferences of 10 songbirds of interest in southeast US woodlands. The results from this study highlight the rapidly changing nature of habitat conditions and how these impact songbird occurrence. Furthermore, Chapter four provides insight into the use of airborne LiDAR to provide specific management guidance to enhance the suitable habitat for 10 songbird species. The collection of studies presented here provides applied tools for the use of airborne and portable LiDAR for rapid assessment and responsive management in southeastern pine woodlands. The advantages of detecting small changes in three-dimensional vegetation structure and how these can impact habitat functionality and suitability for species of interest are explored throughout the next four chapters. The research presented here provides an original and important contribution in the application of airborne and portable LiDAR datasets in forest management and ecological studies.
Show less - Date Issued
- 2011
- Identifier
- CFE0003697, ucf:48831
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003697
- Title
- Finding Consensus Energy Folding Landscapes Between RNA Sequences.
- Creator
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Burbridge, Joshua, Zhang, Shaojie, Hu, Haiyan, Jha, Sumit, University of Central Florida
- Abstract / Description
-
In molecular biology, the secondary structure of a ribonucleic acid (RNA) molecule is closely related to its biological function. One problem in structural bioinformatics is to determine the two- and three-dimensional structure of RNA using only sequencing information, which can be obtained at low cost. This entails designing sophisticated algorithms to simulate the process of RNA folding using detailed sets of thermodynamic parameters. The set of all chemically feasible structures an RNA...
Show moreIn molecular biology, the secondary structure of a ribonucleic acid (RNA) molecule is closely related to its biological function. One problem in structural bioinformatics is to determine the two- and three-dimensional structure of RNA using only sequencing information, which can be obtained at low cost. This entails designing sophisticated algorithms to simulate the process of RNA folding using detailed sets of thermodynamic parameters. The set of all chemically feasible structures an RNA molecule can assume, as well as the energy associated with each structure, is called its energy folding landscape. This research focuses on defining and solving the problem of finding the consensus landscape between multiple RNA molecules. Specifically, we discuss how this problem is equivalent to the problem of Balanced Global Network Alignment, and what effect a solution to this problem would have on our understanding of RNA.Because this problem is known to be NP-hard, we instead define an approximate consensus on a landscape of reduced size, which dramatically reduces the searching space associated with the problem. We use the program RNASLOpt to enumerate all stable local optimal secondary structures in multiple landscapes within a certain energy and stability range of the minimum free energy (MFE) structure. We then encode these using an extended structural alphabet and perform sequence alignment using a structural substitution matrix to find and rank the best matches between the sets based on stability, energy, and structural distance. We apply this method to twenty landscapes from four sets of riboswitches from Bacillus subtillis in order to predict their native (")on(") and (")off(") structures. We find that this method significantly reduces the size of the list of candidate structures, as well as increasing the ranking of previously obscure secondary structures, resulting in more accurate predictions overall. Advances in the field of structural bioinformatics can help elucidate the underlying mechanisms of many genetic diseases.
Show less - Date Issued
- 2015
- Identifier
- CFE0006210, ucf:51109
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006210
- Title
- CHEMICAL STRUCTURE - NONLINEAR OPTICAL PROPERTY RELATIONSHIPS FOR A SERIES OF TWO-PHOTON ABSORBING FLUORENE MOLECULES.
- Creator
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Hales, Joel McCajah, Van Stryland, Eric W., University of Central Florida
- Abstract / Description
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This dissertation reports on the investigation of two-photon absorption (2PA) in a series of fluorenyl molecules. Several current and emerging technologies exploit this optical nonlinearity including two-photon fluorescence imaging, three-dimensional microfabrication, site-specific photodynamic cancer therapy and biological caging studies. The two key features of this nonlinearity which make it an ideal candidate for the above applications are its quadratic dependence on the incident...
Show moreThis dissertation reports on the investigation of two-photon absorption (2PA) in a series of fluorenyl molecules. Several current and emerging technologies exploit this optical nonlinearity including two-photon fluorescence imaging, three-dimensional microfabrication, site-specific photodynamic cancer therapy and biological caging studies. The two key features of this nonlinearity which make it an ideal candidate for the above applications are its quadratic dependence on the incident irradiance and the improved penetration into absorbing media that it affords. As a consequence of the burgeoning field which exploits 2PA, it is a goal to find materials that exhibit strong two-photon absorbing capabilities. Organic materials are promising candidates for 2PA applications because their material properties can be tailored through molecular engineering thereby facilitating optimization of their nonlinear optical properties. Fluorene derivatives are particularly interesting since they possess high photochemical stability for organic molecules and are generally strongly fluorescent. By systematically altering the structural properties in a series of fluorenyl molecules, we have determined how these changes affect their two-photon absorbing capabilities. This was accomplished through characterization of both the strength and location of their 2PA spectra. In order to ensure the validity of these results, three separate nonlinear characterization techniques were employed: two-photon fluorescence spectroscopy, white-light continuum pump-probe spectroscopy, and the Z-scan technique. In addition, full linear spectroscopic characterization was performed on these molecules along with supplementary quantum chemical calculations to obtain certain molecular properties that might impact the nonlinearity. Different designs in chemical architecture allowed investigation of the effects of symmetry, solvism, donor-acceptor strengths, conjugation length, and multi-branched geometries on the two-photon absorbing properties of these molecules. In addition, the means to enhance 2PA via intermediate state resonances was investigated. To provide plausible explanations for the experimentally observed trends, a conceptually simple three level model was employed. The subsequent correlations found between chemical structure and the linear and nonlinear optical properties of these molecules provided definitive conclusions on how to properly optimize their two-photon absorbing capabilities. The resulting large nonlinearities found in these molecules have already shown promise in a variety of the aforementioned applications.
Show less - Date Issued
- 2004
- Identifier
- CFE0000005, ucf:46103
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000005
- Title
- SOCIAL PATHOGENIC SOURCES OF POOR COMMUNITY HEALTH.
- Creator
-
Smith, Hayden, Wan, Thomas, University of Central Florida
- Abstract / Description
-
The United States currently provides a health care system that is neither efficient nor equitable. Despite outspending the world on health care, over three-fourths of developed countries produce better health outcomes (Auerbach et al., 2000). Simultaneously, the "Ecological School of Thought" has documented the large impact that social, economic, and environmental circumstances play in health outcomes. Unfortunately, these 'ecological" studies are frequently conducted without theoretical...
Show moreThe United States currently provides a health care system that is neither efficient nor equitable. Despite outspending the world on health care, over three-fourths of developed countries produce better health outcomes (Auerbach et al., 2000). Simultaneously, the "Ecological School of Thought" has documented the large impact that social, economic, and environmental circumstances play in health outcomes. Unfortunately, these 'ecological" studies are frequently conducted without theoretical justification, and rely solely on a cross-sectional research design and a myriad of unrelated variables. This study represents an important step towards the development of a true theory of "ecology". More specifically, we argue that the adversity associated with socio-economic disadvantage, social disorganization, and a lack of health care resources, leads to adverse health outcomes, represented by sentinel health events. This research employs both a cross-sectional (2000) and longitudinal designs (1990 2000) to assess the antecedents of sentinel health events in 309 United States counties. Structural Equation Modeling was the statistical technique employed in the study. Findings revealed that socioeconomic disadvantage remains a primary contributor to sentinel health. Indeed the economic growth between 1990 and 2000 was associated with increased rates of sentinel health events. Social disorganization was identified as a primary contributor to sentinel health events at a specific time point (2000), but was not significant over time (1990 -2000). Conversely, the inadequacy of health care resources was non-significant in the cross-sectional model (2000), but significant in the longitudinal model (1990 -2000). In both models, racial characteristics were fundamentally linked to ecological predictors of health We found support for the notion that sentinel health events would be reduced through economic equity and the development of healthy environments where community ties are reinforced. Less support is found for saturating given geographical areas with health care resources in order to reduce sentinel health events. Future research should be directed by the theoretical advancements made by this study. More specifically, future studies should examine independent cross-level effects, that is, through the inclusion of behavior variables as mediating factors for ecological constructs.
Show less - Date Issued
- 2007
- Identifier
- CFE0001577, ucf:47108
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001577
- Title
- A FLUID STRUCTURE INTERACTION MODEL OF INTRACORONARY ATHEROSCLEROTIC PLAQUE RUPTURE.
- Creator
-
TEUMA-MELAGO, Eric, Ilegbusi, Olusegun, University of Central Florida
- Abstract / Description
-
Plaque rupture with superimposed thrombosis is the primary cause of acute coronary syndromes of unstable angina, myocardial infarction and sudden death. Although intensive studies in the past decade have shed light on the mechanism that causes unstable atheroma, none has directly addressed the clinical observation that most myocardial infarction (MI) patients have moderate stenoses (less than 50%). Considering the important role the arterial wall compliance and pulsitile blood flow play in...
Show morePlaque rupture with superimposed thrombosis is the primary cause of acute coronary syndromes of unstable angina, myocardial infarction and sudden death. Although intensive studies in the past decade have shed light on the mechanism that causes unstable atheroma, none has directly addressed the clinical observation that most myocardial infarction (MI) patients have moderate stenoses (less than 50%). Considering the important role the arterial wall compliance and pulsitile blood flow play in atheroma rupture, fluid-structure interaction (FSI) phenomenon has been of interest in recent studies. In this thesis, the impact is investigated numerically of coupled blood flow and structural dynamics on coronary plaque rupture. The objective is to determine a unique index that can be used to characterize plaque rupture potential. The FSI index, developed in this study for the first time derives from the theory of buckling of thin-walled cylinder subjected to radial pressure. Several FSI indices are first defined by normalizing the predicted hemodynamic endothelial shear stress by the structural stresses, specifically, by the maximum principal stress (giving the ratio ), and the Von Mises stress (giving the ratio ). The predicted at the location of maximum (i.e { }) denoted , is then chosen to characterize plaque rupture through systematic investigation of a variety of plaque characteristics and simulated patient conditions. The conditions investigated include varying stenosis levels ranging from 20% to 70%, blood pressure drop ranging from 3125 Pa/m to 9375 Pa/m, fibrous cap thickness ranging from to , lipid pool location ranging from the leading to the trailing edge of plaque, lipid pool volume relative to stenosis volume ranging from 24% to 80%, Calcium volume relative to stenosis volume ranging from 24% to 80% and arterial remodeling. The predicted varies with the stenosis severity and indicates that the plaques investigated are prone to rupture at approximately 40-45% stenosis levels. It predicts that high pressure significantly lowers the threshold stenosis rate for plaque rupture. In addition, the plaque potential to rupture increases for relatively thin fibrous cap, lipid core located near the leading plaque shoulder, and dramatically for relative lipid pool volume above 60%. However, calcium deposit has marginal effect on plaque rupture. Overall, the predicted results are consistent with clinical observations, indicating that the has the potential to characterize plaque rupture when properly established. In the appendix, the unsteady flow in a collapsible tube model of a diseased artery is solved analytically. The novelty of our approach is that the set of governing equations is reduced to a single integro-differential equation in the transient state. The equation was solved using the finite difference method to obtain the pressure and compliant wall behavior. The analytical approach is less computer-intensive than solving the full set of governing equations. The predicted membrane deflection is quite large at low inlet velocity, suggesting possible approach to breakdown in equilibrium. As the transmural pressure increases with wall deflection, bulges appear at the ends of the membrane indicating critical stage of stability, consistent with previous studies. An increase in wall thickness reduces the wall deflection and ultimately results in its collapse. The collapse is due to breakdown in the balance of wall governing equation. An increase in internal pressure is required to maintain membrane stability.
Show less - Date Issued
- 2006
- Identifier
- CFE0001471, ucf:47084
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001471
- Title
- POLICE ORGANIZATIONAL PERFORMANCE IN THE STATE OF FLORIDA:CONFIRMATORY ANALYSIS OF THE RELATIONSHIP OF THE ENVIRONMENT AND DESIGN STRUCTURE TO PERFORMANCE.
- Creator
-
Goltz, Jeffrey, Wan, Thomas, University of Central Florida
- Abstract / Description
-
To date, police organizations have not been rigorously analyzed by organizational scholars and most analysis of these organizations has been captured through a single construct. The purpose of this study is to develop confirmatory police organizational analysis by validating a multi-dimensional conceptual framework that explains the relationships among three constructs: environmental constraints, the design structures of police organizations, and organizational performance indicators. The...
Show moreTo date, police organizations have not been rigorously analyzed by organizational scholars and most analysis of these organizations has been captured through a single construct. The purpose of this study is to develop confirmatory police organizational analysis by validating a multi-dimensional conceptual framework that explains the relationships among three constructs: environmental constraints, the design structures of police organizations, and organizational performance indicators. The modeling is deeply rooted in contingency theory, and the influence of isomorphism and institutional theory on the covariance structure model are investigated. One hundred and thirteen local police organizations from the State of Florida are included in this non-experimental, cross-sectional study to determine the direct effect of the environmental constraints on the performance of police organizations, the indirect effect of environmental constraints on the performance of police organizations via the organizational design structure of police organizations, and the direct affect of organizational design structure on performance of police organizations. For the first time, structural equation modeling and data envelopment analysis are used together to confirm the effects of the environment on police organization structure and performance. The results indicate that environmental social economic disparity indicators have a large positive effect on police resources and a medium effect on police efficiency. Propensity of crime indicators has a large negative effect on police resources, and population density has a small to medium negative effect on crime clearance. Structure has a much smaller effect on performance than the environment. The results of the efficiency analysis revealed unexpected findings. Three of the top five largest police organizations in the study scored maximum efficiency. The cause of this unexpected result is explained and confirmed in the covariance model. The study methodology and results enhances the understanding of the relationship among the constructs while subjecting environmental and police organizational data to two comprehensive analytical techniques. The policy implications and practical contributions of the study provide new knowledge and information to organizational management of police organizations. Furthermore, the study establishes a new approach to police organizational analysis and police services management research called Police Services Management Research (PSMR) that encompasses a variety of disciplines with a primary responsibility of theory building and the selection of theoretical framework.
Show less - Date Issued
- 2006
- Identifier
- CFE0001363, ucf:47000
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001363
- Title
- DISSIPATIVE SOLITONS IN THE CUBICQUINTIC COMPLEX GINZBURGLANDAU EQUATION:BIFURCATIONS AND SPATIOTEMPORAL STRUCTURE.
- Creator
-
Mancas, Ciprian, Choudhury, Roy S., University of Central Florida
- Abstract / Description
-
Comprehensive numerical simulations (reviewed in Dissipative Solitons, Akhmediev and Ankiewicz (Eds.), Springer, Berlin, 2005) of pulse solutions of the cubic--quintic Ginzburg--Landau equation (CGLE), a canonical equation governing the weakly nonlinear behavior of dissipative systems in a wide variety of disciplines, reveal various intriguing and entirely novel classes of solutions. In particular, there are five new classes of pulse or solitary waves solutions, viz. pulsating, creeping,...
Show moreComprehensive numerical simulations (reviewed in Dissipative Solitons, Akhmediev and Ankiewicz (Eds.), Springer, Berlin, 2005) of pulse solutions of the cubic--quintic Ginzburg--Landau equation (CGLE), a canonical equation governing the weakly nonlinear behavior of dissipative systems in a wide variety of disciplines, reveal various intriguing and entirely novel classes of solutions. In particular, there are five new classes of pulse or solitary waves solutions, viz. pulsating, creeping, snake, erupting, and chaotic solitons. In contrast to the regular solitary waves investigated in numerous integrable and non--integrable systems over the last three decades, these dissipative solitons are not stationary in time. Rather, they are spatially confined pulse--type structures whose envelopes exhibit complicated temporal dynamics. The numerical simulations also reveal very interesting bifurcations sequences of these pulses as the parameters of the CGLE are varied. In this dissertation, we develop a theoretical framework for these novel classes of solutions. In the first part, we use a traveling wave reduction or a so--called spatial approximation to comprehensively investigate the bifurcations of plane wave and periodic solutions of the CGLE. The primary tools used here are Singularity Theory and Hopf bifurcation theory respectively. Generalized and degenerate Hopf bifurcations have also been considered to track the emergence of global structure such as homoclinic orbits. However, these results appear difficult to correlate to the numerical bifurcation sequences of the dissipative solitons. In the second part of this dissertation, we shift gears to focus on the issues of central interest in the area, i.e., the conditions for the occurrence of the five categories of dissipative solitons, as well the dependence of both their shape and their stability on the various parameters of the CGLE, viz. the nonlinearity, dispersion, linear and nonlinear gain, loss and spectral filtering parameters. Our predictions on the variation of the soliton amplitudes, widths and periods with the CGLE parameters agree with simulation results. For this part, we develop and discuss a variational formalism within which to explore the various classes of dissipative solitons. Given the complex dynamics of the various dissipative solutions, this formulation is, of necessity, significantly generalized over all earlier approaches in several crucial ways. Firstly, the two alternative starting formulations for the Lagrangian are recent and not well explored. Also, after extensive discussions with David Kaup, the trial functions have been generalized considerably over conventional ones to keep the shape relatively simple (and the trial function integrable!) while allowing arbitrary temporal variation of the amplitude, width, position, speed and phase of the pulses. In addition, the resulting Euler--Lagrange equations are treated in a completely novel way. Rather than consider the stable fixed points which correspond to the well--known stationary solitons or plain pulses, we use dynamical systems theory to focus on more complex attractors viz. periodic, quasiperiodic, and chaotic ones. Periodic evolution of the trial function parameters on stable periodic attractors constructed via the method of multiple scales yield solitons whose amplitudes are non--stationary or time dependent. In particular, pulsating, snake (and, less easily, creeping) dissipative solitons may be treated in this manner. Detailed results are presented here for the pulsating solitary waves --- their regimes of occurrence, bifurcations, and the parameter dependences of the amplitudes, widths, and periods agree with simulation results. Finally, we elucidate the Hopf bifurcation mechanism responsible for the various pulsating solitary waves, as well as its absence in Hamiltonian and integrable systems where such structures are absent. Results will be presented for the pulsating and snake soliton cases. Chaotic evolution of the trial function parameters in chaotic regimes identified using dynamical systems analysis would yield chaotic solitary waves. The method also holds promise for detailed modeling of chaotic solitons as well. This overall approach fails only to address the fifth class of dissipative solitons, viz. the exploding or erupting solitons.
Show less - Date Issued
- 2007
- Identifier
- CFE0001571, ucf:47116
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001571
- Title
- CATEGORICAL PROPERTIES OF LATTICE-VALUED CONVERGENCE SPACES.
- Creator
-
Flores, Paul, Richardson, Gary, University of Central Florida
- Abstract / Description
-
This work can be roughly divided into two parts. Initially, it may be considered a continuation of the very interesting research on the topic of Lattice-Valued Convergence Spaces given by Jäger [2001, 2005]. The alternate axioms presented here seem to lead to theorems having proofs more closely related to standard arguments used in Convergence Space theory when the Lattice is L=.Various Subcategories are investigated. One such subconstruct is shown to be isomorphic to the category of...
Show moreThis work can be roughly divided into two parts. Initially, it may be considered a continuation of the very interesting research on the topic of Lattice-Valued Convergence Spaces given by Jäger [2001, 2005]. The alternate axioms presented here seem to lead to theorems having proofs more closely related to standard arguments used in Convergence Space theory when the Lattice is L=.Various Subcategories are investigated. One such subconstruct is shown to be isomorphic to the category of Lattice Valued Fuzzy Convergence Spaces defined and studied by Jäger . Our principal category is shown to be a topological universe and contains a subconstruct isomorphic to the category of probabilistic convergence spaces discussed in Kent and Richardson when L=. Fundamental work in lattice-valued convergence from the more general perspective of monads can be found in Gähler . Secondly, diagonal axioms are defined in the category whose objects consist of all the lattice valued convergence spaces. When the latter lattice is linearly ordered, a diagonal condition is given which characterizes those objects in the category that are determined by probabilistic convergence spaces which are topological. Certain background information regarding filters, convergence spaces, and diagonal axioms with its dual are given in Chapter 1. Chapter 2 describes Probabilistic Convergence and associated Diagonal axioms. Chapter 3 defines Jäger convergence and proves that Jäger's construct is isomorphic to a bireflective subconstruct of SL-CS. Furthermore, connections between the diagonal axioms discussed and those given by Gähler are explored. In Chapter 4, further categorical properties of SL-CS are discussed and in particular, it is shown that SL-CS is topological, cartesian closed, and extensional. Chapter 5 explores connections between diagonal axioms for objects in the sub construct δ(PCS) and SL-CS. Finally, recommendations for further research are provided.
Show less - Date Issued
- 2007
- Identifier
- CFE0001715, ucf:47292
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001715
- Title
- EXTRACTING QUANTITATIVE INFORMATIONFROM NONNUMERIC MARKETING DATA: AN AUGMENTEDLATENT SEMANTIC ANALYSIS APPROACH.
- Creator
-
Arroniz, Inigo, Michaels, Ronald, University of Central Florida
- Abstract / Description
-
Despite the widespread availability and importance of nonnumeric data, marketers do not have the tools to extract information from large amounts of nonnumeric data. This dissertation attempts to fill this void: I developed a scalable methodology that is capable of extracting information from extremely large volumes of nonnumeric data. The proposed methodology integrates concepts from information retrieval and content analysis to analyze textual information. This approach avoids a pervasive...
Show moreDespite the widespread availability and importance of nonnumeric data, marketers do not have the tools to extract information from large amounts of nonnumeric data. This dissertation attempts to fill this void: I developed a scalable methodology that is capable of extracting information from extremely large volumes of nonnumeric data. The proposed methodology integrates concepts from information retrieval and content analysis to analyze textual information. This approach avoids a pervasive difficulty of traditional content analysis, namely the classification of terms into predetermined categories, by creating a linear composite of all terms in the document and, then, weighting the terms according to their inferred meaning. In the proposed approach, meaning is inferred by the collocation of the term across all the texts in the corpus. It is assumed that there is a lower dimensional space of concepts that underlies word usage. The semantics of each word are inferred by identifying its various contexts in a document and across documents (i.e., in the corpus). After the semantic similarity space is inferred from the corpus, the words in each document are weighted to obtain their representation on the lower dimensional semantic similarity space, effectively mapping the terms to the concept space and ultimately creating a score that measures the concept of interest. I propose an empirical application of the outlined methodology. For this empirical illustration, I revisit an important marketing problem, the effect of movie critics on the performance of the movies. In the extant literature, researchers have used an overall numerical rating of the review to capture the content of the movie reviews. I contend that valuable information present in the textual materials remains uncovered. I use the proposed methodology to extract this information from the nonnumeric text contained in a movie review. The proposed setting is particularly attractive to validate the methodology because the setting allows for a simple test of the text-derived metrics by comparing them to the numeric ratings provided by the reviewers. I empirically show the application of this methodology and traditional computer-aided content analytic methods to study an important marketing topic, the effect of movie critics on movie performance. In the empirical application of the proposed methodology, I use two datasets that combined contain more than 9,000 movie reviews nested in more than 250 movies. I am restudying this marketing problem in the light of directly obtaining information from the reviews instead of following the usual practice of using an overall rating or a classification of the review as either positive or negative. I find that the addition of direct content and structure of the review adds a significant amount of exploratory power as a determinant of movie performance, even in the presence of actual reviewer overall ratings (stars) and other controls. This effect is robust across distinct opertaionalizations of both the review content and the movie performance metrics. In fact, my findings suggest that as we move from sales to profitability to financial return measures, the role of the content of the review, and therefore the critic's role, becomes increasingly important.
Show less - Date Issued
- 2007
- Identifier
- CFE0001617, ucf:47164
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001617
- Title
- EYES IN THE TEXT: SURVEYING THE OCULAR AESTHETIC IN PAT BARKER'S WAR TRILOGY.
- Creator
-
Hammond, James, Campbell, James, University of Central Florida
- Abstract / Description
-
ABSTRACT In 1991, British novelist Patricia Barker published Regeneration, the first of three novels that portrayed the exploits of both factual and fictional characters during the darkest days of WWI. Barker's Eye in the Door (1993), followed by The Ghost Road (1995) for which she won the Booker Prize for Fiction, completed the series that explored the effects of combat on the human psyche. What emerges as a dominant feature of Barker's war novels is her depiction of the ocular sense....
Show moreABSTRACT In 1991, British novelist Patricia Barker published Regeneration, the first of three novels that portrayed the exploits of both factual and fictional characters during the darkest days of WWI. Barker's Eye in the Door (1993), followed by The Ghost Road (1995) for which she won the Booker Prize for Fiction, completed the series that explored the effects of combat on the human psyche. What emerges as a dominant feature of Barker's war novels is her depiction of the ocular sense. Reminiscent of Orwellianism, Barker's texts contain a seemingly ubiquitous ocular presence. For example, neurasthenic patients are scrutinized by army psychiatrists, objectors and subversives are spied upon or imprisoned so that their activities may be observed, and combatants are faced with the challenge of reconciling the horrifying events they have witnessed in combat. This study investigates the role and importance of Pat Barker's depiction of eyes and visuality in her war trilogy. The overreaching goal of the thesis to examine Barker's aestheticized notion of ocularity. It is my aim to come some conclusions about how vision / ocularity signal the emergence of a few central themes in the texts such as power relationships, objectification, exposure and the transgression of boundaries. The social and linguistic theories of Michael Foucault, Roland Barthes, Georges Bataille, Martin Jay and others who have addressed the themes of perception and ocular symbolism will be introduced into my discussion with the aim of providing a theoretic foundation to many of my assertions. Chapters will begin with an interpretation of a piece of theoretical writing by one of these authors followed by an analysis of Barker's texts that incorporates the major tenets of that theory. These tenets will serve as a basis to my discussion and it is my hope that, through the creative application of theoretical writing, I will address a number of aspects of Barker's work, especially in relation to her ocular imagery, that that have thus far gone unexplored.
Show less - Date Issued
- 2005
- Identifier
- CFE0000832, ucf:46681
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0000832
- Title
- SEX EDUCATION OR SELF EDUCATION? LGBT+ EXPERIENCES WITH EXCLUSIONARY CURRICULA.
- Creator
-
Reeves, Karli, Mishtal, Joanna, University of Central Florida
- Abstract / Description
-
Though much research exists on LGBT+ exclusion from school-based sexual and reproductive health (SRH) education, the strategies used by LGBT+ individuals during their search for knowledge regarding the subject are not as widely documented. Using the ethnographic research method of semi-structured interviews, this research explores the experiences of young LGBT+ adults with formal sexual and reproductive health education and examines the self-education methods employed by this population in...
Show moreThough much research exists on LGBT+ exclusion from school-based sexual and reproductive health (SRH) education, the strategies used by LGBT+ individuals during their search for knowledge regarding the subject are not as widely documented. Using the ethnographic research method of semi-structured interviews, this research explores the experiences of young LGBT+ adults with formal sexual and reproductive health education and examines the self-education methods employed by this population in the context of exclusionary and cisheteronormative curricula. This project also functions to contribute to existing literature in the field of anthropology and other social sciences regarding the subject of SRH education, particularly LGBT+ SRH education. Furthermore, this study supports the need for additional research through the use of applied anthropology concerning interactions between institutions, policy and individual experiences of health.
Show less - Date Issued
- 2019
- Identifier
- CFH2000500, ucf:45692
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000500
- Title
- INCREASING ORAL LANGUAGE FLUENCY AND SYNTACTIC STRUCTURE THROUGH A BALANCED READING APPROACH: A CASE STUDY OF A FIVE-YEAR OLD BEGINNING READER OF THE EDGE OF THE AUTISM SPECTRUM.
- Creator
-
Palmer, Kelly, Roberts, Sherron, University of Central Florida
- Abstract / Description
-
In recent years, a significant surge has occurred in the amount of children who are being diagnosed with a disorder on the autism spectrum. Current statistics from the Center for Disease Control and Prevention (2011) show that 1 in 110 children in the United States have an Autism Spectrum Disorder (ASD) and that the diagnosis of such is estimated to grow prodigiously due to a variety of different aspects, such as an ever-increasing broadening definition of autism, an inclusion of autism as a...
Show moreIn recent years, a significant surge has occurred in the amount of children who are being diagnosed with a disorder on the autism spectrum. Current statistics from the Center for Disease Control and Prevention (2011) show that 1 in 110 children in the United States have an Autism Spectrum Disorder (ASD) and that the diagnosis of such is estimated to grow prodigiously due to a variety of different aspects, such as an ever-increasing broadening definition of autism, an inclusion of autism as a disability category under the Individuals with Disabilities Education Act of 1990, improved diagnostic methods, and some other unknown factors (In Nickel's work as cited by Nickels in 2010). Also, because a lack of or weakness in communication skills is a common characteristic for students who have an ASD, receiving early intervention to increase communication is imperative for this population. In consideration of this premise, this study looks at whether using a blended, balanced mode of reading instruction, the Language Experience Approach (Stauffer, 1970; Van Allen, 1970) and the work of Patricia Oelwein (1995), through written means can improve oral language fluency output and syntactical structure concurrently for a student who has suffered from many of the symptoms of ASD, but has not been clinically diagnosed. Along with the collection of qualitative data aggregated throughout this study through observational means, quantitative data was also collected before, during, and after the intervention to measure the effects on the subject. Quantitative data was obtained from a Letter-Identification Assessment (Clay 2005), the QRI-5 (Leslie & Caldwell, 2011), the Peabody Picture Vocabulary Test (Dunn & Dunn, 1997) , and Mean Length of Utterance (MLU). Results obtained from this study showed that the interventions had a positive effect on the subject in terms of listening, speaking, reading, and writing where the fluency and complexity of the subject's speech patterns and ability to read and write improved over the course of the intervention period.
Show less - Date Issued
- 2012
- Identifier
- CFH0004239, ucf:44905
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH0004239