View All Items

Title: High Volume Fraction Mg-based Nanocomposites: Processing, Microstructure and Mechanical Behavior.
Creator: Liu, Jinling, An, Linan, Suryanarayana, Challapalli, Fang, Jiyu, Bai, Yuanli, Lin, Kuo-Chi, University of Central Florida
Abstract / Description: Mg-based metal matrix nanocomposites (MMNCs) with mechanical properties, superior to those of coarse-grained composites, are promising structural materials for applications in the automotive and aerospace industries. The research in this area was primarily focused earlier on either micro-scaled reinforcements or nano-scaled reinforcements with very low volume fractions. MMNCs with high volume fractions have not been explored yet. In this research, we study the processing, microstructures and...
Show moreMg-based metal matrix nanocomposites (MMNCs) with mechanical properties, superior to those of coarse-grained composites, are promising structural materials for applications in the automotive and aerospace industries. The research in this area was primarily focused earlier on either micro-scaled reinforcements or nano-scaled reinforcements with very low volume fractions. MMNCs with high volume fractions have not been explored yet. In this research, we study the processing, microstructures and properties of MMNCs containing ceramic nanoparticles up to 30 vol.%.We first investigated the mechanical alloying of Al2O3 nanoparticles and pure Mg under high-energy ball milling conditions. The phase evolution and their distribution were evaluated as a function of milling time. Then, the thermal stability of the formed nanocomposites was investigated by annealing it at high temperatures. It indicated that an exchange reaction had occurred to a large extent between Mg and Al2O3 resulting in the formation of Al and MgO phases. Additionally, the reaction between Al and un-reacted Mg led to the formation of Mg-Al intermetallics.Due to the reaction between Mg and Al2O3 during the milling and annealing process, we attempted to synthesize Mg/SiC nanocomposites. The mixed powders containing 0, 5, 10 and 15 vol.% SiC were produced by high energy ball milling and then the powders were consolidated via spark plasma sintering. The phase constitutions and microstructures of the Mg/SiC nanocomposites were characterized. SiC nanoparticles (average particle size ~14 nm) appear to be homogeneously dispersed within the matrix, and the average inter-particle spacings of all the Mg/SiC nanocomposites were smaller than 50 nm. Microscopic methods, even at high magnifications did not reveal any significant porosity in the as-processed MMNCs.Mechanical characterization of the Mg/SiC nanocomposites was conducted using the microindentation test. Besides the microhardness test, different intermediate pause times and loading rates were used to evaluate the stiffness and loading rate sensitivity of our samples. The abnormal microhardness and loading rate sensitivity were showed for the Mg-15 vol.% SiC samples. At the same time, the monotonic increase of stiffness with volume fraction was exhibited in the Mg/SiC nanocomposites.Finally, we investigated the quasi-static and dynamic response of Mg/SiC nanocomposites and microcomposites, and discussed the underlying mechanisms. Strain softening was noticed in the milled Mg sample under quasi-static compression. Similarly, the strengthening effect leveling off was also observed in the Mg-15 vol.% SiC samples under either quasi-static or high-strain rate uniaxial compression conditions. No significant plastic deformation was observed in the Mg/SiC nanocomposites. The estimated strain rate sensitivity of all the Mg/SiC nanocomposites in this work was around 0.03, which is much smaller than 0.3 and 0.6, observed for 100 nm and 45 nm grain size pure Mg individually. In particular, the existing models fail in predicting the inverse volume fraction effect, and other mechanisms are yet to be explored. The presence of SiC nanoparticles may play an important role that leads to this difference.
Show less
Date Issued: 2013
Identifier: CFE0004879, ucf:49672
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004879

Title: An investigation into a least squares method for image registration.
Creator: Cordon, Ernest William, Patz, B.W., Engineering
Abstract / Description: Florida Technological University College of Engineering Thesis; One of the problems associated with the automatic image processing of satellite photographs such as weather maps is the need for image registration; that is, the fitting of a map that has some translational and rotational bias to a known data base. This paper investigates a least square method of image registration using an image that has been converted into a boundary map with a pixel representation 1 for land, -1 for water and...
Show moreFlorida Technological University College of Engineering Thesis; One of the problems associated with the automatic image processing of satellite photographs such as weather maps is the need for image registration; that is, the fitting of a map that has some translational and rotational bias to a known data base. This paper investigates a least square method of image registration using an image that has been converted into a boundary map with a pixel representation 1 for land, -1 for water and zero for cloud pixels. A sampled correlation array is constructed by shifting the weather map to locations on a given grid, centered around a sampled correlation peak, and performing an accumulation of the pixel-by-pixel comparisons between the weather map and its data base over the whole map or a smaller search window. A least square approximation 0 f the translational and rotational bias is performed using the data from this sampled correlation array, fitted against the shape of an elliptical cone.
Show less
Date Issued: 1978
Identifier: CFR0003516, ucf:53005
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0003516

Title: A microcomputer implementation of real time, continuously programmable digital filters.
Creator: Storma, William Edward, Simmons, Fred O., Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; When a filter transfer function in s is replaced with the bilinear transform in z, t he resulting discrete model represents the original continuous model within a second order accuracy of integration. A unique set of recently discovered minimum memory algorithms that perform the bilinear transform on a continuous transfer function are implemented on an INTEL 8080 microprocessor system. Scal1ng techniques are used to frequency scale...
Show moreUniversity of Central Florida College of Engineering Thesis; When a filter transfer function in s is replaced with the bilinear transform in z, t he resulting discrete model represents the original continuous model within a second order accuracy of integration. A unique set of recently discovered minimum memory algorithms that perform the bilinear transform on a continuous transfer function are implemented on an INTEL 8080 microprocessor system. Scal1ng techniques are used to frequency scale all transfer functions to a standardized frequency. All data words are represented in a signed binary double precision format to maintain higher calculation speed and accuracy. Three test case transfer functions of different order are implemented using the bilinear transform algorithms. First, the algorithms are used to generate the three discrete models. Second, the continuous time models are driven by a step input function, generating a continuous time output. Third, the step function input is discretized and used to drive the bilinear algorithm derived models. Finally, the discrete outputs are compared with the continuous time outputs to validate and evaluate the software techniques used to implement the bilinear algorithms, which imply that the techniques provide a basis for new hardware designs.
Show less
Date Issued: 1979
Identifier: CFR0003497, ucf:53140
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0003497

Title: An analytical model for evaluating database update schemes.
Creator: Kinsley, Kathryn C., Hughes, Charles E., Arts and Sciences
Abstract / Description: University of Central Florida College of Arts and Sciences Thesis; A methodology is presented for evaluating the performance of database update schemes. The methodology uses the M/Hr/1 queueing model as a basis for this analysis and makes use of the history of how data is used in the database. Parameters have been introduced which can be set based on the characteristics of a specific system. These include update to retrieval ratio, average file size, overhead, block size and the expected...
Show moreUniversity of Central Florida College of Arts and Sciences Thesis; A methodology is presented for evaluating the performance of database update schemes. The methodology uses the M/Hr/1 queueing model as a basis for this analysis and makes use of the history of how data is used in the database. Parameters have been introduced which can be set based on the characteristics of a specific system. These include update to retrieval ratio, average file size, overhead, block size and the expected number of items in the database. The analysis is specifically directed toward the support of derived data within the relational model. Three support methods are analyzed. These are first examined in a central database system. The analysis is then extended in order to measure performance in a distributed system. Because concurrency is a major problem in a distributive system, the support of derived data is analyzed with respect to three distributive concurrency control techniques -- master/slave, distributed and synchronized. In addition to its use as a performance predictor, the development of the methodology serves to demonstrate how queueing theory may be used to investigate other related database problems. This is an important benefit due to this lack of fundamental results in the area of using queueing theory to analyze database performance.
Show less
Date Issued: 1983
Identifier: CFR0011600, ucf:53041
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011600

Title: Realization of a fast automatic correlation algorithm for registration of satellite images.
Creator: Kassak, John E., Patz, B.W., Engineering
Abstract / Description: Florida Technological University College of Engineering Thesis; The requirement for a fast automated correlation algorithm for registration of satellite images is discussed. An overview of current registration techniques is presented indicating a correlator, matching binary maps compressed from the original imagery, may provide the required throughput when implemented with a dedicated hardware/processor. An actual registration problem utilizing GOES digitally processed imagery is chosen and...
Show moreFlorida Technological University College of Engineering Thesis; The requirement for a fast automated correlation algorithm for registration of satellite images is discussed. An overview of current registration techniques is presented indicating a correlator, matching binary maps compressed from the original imagery, may provide the required throughput when implemented with a dedicated hardware/processor. An actual registration problem utilizing GOES digitally processed imagery is chosen and defined. The realization of a fast correlator, matching image input data with sampled data base reference image data in real time is considered.
Show less
Date Issued: 1978
Identifier: CFR0003495, ucf:53010
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0003495

Title: Computer Method for Airport Noise Exposure Forecast.
Creator: Bateman, John M., Ventre, Gerald G., Engineering
Abstract / Description: Florida Technological University College of Engineering Thesis; The major problem facing air transportation for the next decade is aircraft noise. The noise level due to the operation of large jet aircraft has created a very serious annoyance problem to the people living near of adjacent to jet airports. The noise problem has developed both for take-off and landing operations of these aircraft with take -off noise causing the greatest annoyance factor. A technique called Noise Exposure...
Show moreFlorida Technological University College of Engineering Thesis; The major problem facing air transportation for the next decade is aircraft noise. The noise level due to the operation of large jet aircraft has created a very serious annoyance problem to the people living near of adjacent to jet airports. The noise problem has developed both for take-off and landing operations of these aircraft with take -off noise causing the greatest annoyance factor. A technique called Noise Exposure Forcast (NEF) has been developed to identify the annoyance factor of these noises to people and activities on the ground. With these NEF ratings or numbers, planners can better determined the type of buildings and activities to locate in the vicinity of airports. This paper presents a computer method for determining NEF areas or contours which eliminate the necessity of performing laborous hand calculations and iterations normally required to determine a given NEF locus about an airport. A land use compatability table showing land use versus NEF numbers is given on page 3. A sample computer program is given on pages 21 through 25 of teh appendix and a sample computer output page is given on page 26. The computer technique developed for this paper can be used for any airport.
Show less
Date Issued: 1972
Identifier: CFR0012156, ucf:53130
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0012156

Title: Beyond Compliance: Examining the Role of Motivation in Vigilance Performance.
Creator: Dewar, Alexis, Szalma, James, Sims, Valerie, Hancock, Peter, Matthews, Gerald, University of Central Florida
Abstract / Description: Vigilance, or sustained attention, is the capacity to attend to information for a prolonged period of time (Davies (&) Parasuraman, 1982; Jerison, 1970; Warm, 1977). Due to limitations of the human nervous system, as well as the environmental context, attention can begin to wane over time. This results in a phenomenon referred to as the vigilance decrement, or a decline in vigilance performance as a function of time. The vigilance decrement can manifest as poorer attention and is thusly...
Show moreVigilance, or sustained attention, is the capacity to attend to information for a prolonged period of time (Davies (&) Parasuraman, 1982; Jerison, 1970; Warm, 1977). Due to limitations of the human nervous system, as well as the environmental context, attention can begin to wane over time. This results in a phenomenon referred to as the vigilance decrement, or a decline in vigilance performance as a function of time. The vigilance decrement can manifest as poorer attention and is thusly associated with poor performance, which is defined behaviorally as more lapses in the detection of critical signals and an increase in response time to these signals during watch. Given this, the present dissertation seeks to systematically examine the impact of two types of motivation (i.e., achievement motivation, autonomous motivation) on vigilance performance across four experiments. The present experiments manipulate information processing type, source complexity, and motivational task demands. Three hundred and ninety-eight participants completed either a cognitive task or sensory task, which were psychophysically equated in previous studies (Szalma (&) Teo, 2012; Teo, Szalma, (&) Schmidt, 2011), with or without motivational instructions, and with either low, medium, or high source complexity. Performance measures, perceived stress and workload, and changes to state motivation and engagement at pre-task and post-task are interpreted across three theories of information processing: resource-depletion theory, mind-wandering theory, and mindlessness theory. The results of each of the four studies are discussed in terms of overall support for the resource-depletionist account. The limitations of the present set of experiments and the future directions for research on motivation and sustained attention are also discussed.
Show less
Date Issued: 2017
Identifier: CFE0006582, ucf:51312
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006582

Title: Identity construction and information processing in a coaching relationship: The effects of coach behavior on coachee goal-setting and commitment.
Creator: Coultas, Christopher, Salas, Eduardo, Salazar, Maritza, Burke, Shawn, Fritzsche, Barbara, University of Central Florida
Abstract / Description: Coaching (professional, business, executive, leadership) has been shown to be effective generally speaking, but questions remain regarding the explanatory mechanisms underlying coaching. I first propose a context-general model that unpacks the sociocognitive dynamics within coaching. The model explains the emergence of different types of coaching relationships, and how the nature of these relationships differentially determine coaching outcomes. Research and theory on social identity...
Show moreCoaching (professional, business, executive, leadership) has been shown to be effective generally speaking, but questions remain regarding the explanatory mechanisms underlying coaching. I first propose a context-general model that unpacks the sociocognitive dynamics within coaching. The model explains the emergence of different types of coaching relationships, and how the nature of these relationships differentially determine coaching outcomes. Research and theory on social identity construction and information processing in dyads provides the foundation upon which I outline a model describing the process and dynamics of coaching identity emergence. Beyond this emergence, my proposed model states that the coachee's understanding of appropriate interpersonal relations and division of labor between coach and coachee (i.e., his/her situated coaching identity or coaching structure schema) should partially dictate the focus and depth of the coachee's information processing during a coaching engagement. Past research has shown information processing to be a key determinant of decision-making and goal commitment, both of which are desirable outcomes within the coaching domain.To explore these issues, I developed a coaching exercise which simulated some of the early aspects of business, leadership, or executive coaching. During this simulation, participants were guided through a process which enabled them to think and talk about their strengths and weaknesses when using different conflict management behaviors. In discussing these aspects of conflict management, participants and coaches (i.e., trained research associates) walked through a supplementary process to facilitate the development of a series of goals (an (")action plan(")) that would enable the participant to improve his or her conflict management behaviors. At the end of the coaching session, participants were asked to what extent they felt committed to the goals they had developed and whether or not they expected them to be efficacious. Throughout the coaching session, participants were also asked at designated break points to report their levels of information processing and their understanding of the coaching structure schema for that particular coaching relationship. The experimental manipulation was presented at the beginning of the session, wherein the coach would explain to the coachee what the ideal nature of coaching should be. These explanations varied in terms of ascribing responsibility and division of labor (-) either to a generic coaching process, to the skill and ability of the coach, to the creativity of the participant, or to the joint interaction between coach and participant. Among other things, I hypothesized that coaching structure schemas that emphasized the participant's role in the coaching process would encourage more information processing, and consequently higher levels of goal commitment. Hypotheses were largely confirmed, showing that information processing and coaching structure schemas are important predictors of goal commitment at the end of one coaching session. The effects of the manipulation were mixed. Claiming behaviors (-) that is, the coach ascribing responsibility for coaching effectiveness to him/herself (-) were only marginally effective in shaping participants' coaching structure schemas. Granting behaviors (-) communicating to the participant that they are responsible for coaching effectiveness (-) were much more effective in facilitating helpful information processing and driving higher levels of goal commitment. One possible explanation for the relative effectiveness of granting over claiming may be that claiming requires a degree of credibility which the coach (again, a trained research associate) had not attained with the participants. Other findings pertain to: (1) the unique variance that independent measures of coach- and coachee-relevant structure schemas contribute to models predicting information processing and goal commitment, (2) the importance of identifying the type or focus of coachee information processing, and (3) the role that psychological mindedness may play in characterizing a more (")coachable(") coachee. Implications include: (1) measuring coachees' coaching structure schemas, (2) intentionally encouraging a more appropriate schema, (3) measuring coachees' psychological mindedness prior to coaching, and (4) dynamically monitoring coachees' schema and their information processing in order to assure better coaching effectiveness. Future researchers should explore ways to enact these implications and also to further explore the theoretical components of these practical implications, such as: (1) measurement methods for better assessing coaching schemas and information processing, (2) what the ideal timings are for different kinds of coaching schemas, and (3) different ways to encourage maximally adaptive and appropriate coaching structure schemas.
Show less
Date Issued: 2014
Identifier: CFE0005319, ucf:50523
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005319

Title: Managerial process of discount decision-making in the lodging industry: The role of human agency.
Creator: Lee, Seung Hyun, Croes, Robertico, Kwun, David, Rivera, Manuel, Sivo, Stephen, Bai, Xiucheng, University of Central Florida
Abstract / Description: Management faces a paradox in managing discrepancies between actual demand and expected demand in daily operations, thereby requiring constant adjustments in pricing under the supervision of management in the short term. The purpose of this study is to determine how discount choices are created and to understand information processing related to the pricing and discounting decision-making process as well as narrating the events, stages, and cycles of choices made by hotel managers. This study...
Show moreManagement faces a paradox in managing discrepancies between actual demand and expected demand in daily operations, thereby requiring constant adjustments in pricing under the supervision of management in the short term. The purpose of this study is to determine how discount choices are created and to understand information processing related to the pricing and discounting decision-making process as well as narrating the events, stages, and cycles of choices made by hotel managers. This study also determines the role of human judgment based on contextual factors in the decision-making process. This mixed methods research design consists of three steps: observation, classification, and association. First, the observation stage includes the careful observation, documentation, and measurement of the phenomena within the social and institutional context through structured interviews with hotel managers. Second, abstractions are classified into categories based on the attributes of the phenomena. Information attributes are categorized into static and dynamic information, and the source of information is characterized in external and internal sources. Third, the association between the category-defining attributes and the outcome observed (discount or not) is explored using conjoint analysis. This last stage attempts to investigate not only the importance of information attributes, but also the role of social-, institution-, and human agency-related influences in managers' discounting decisions.The major findings of the study are as follows. First, habitual practices are identified to show how the classification of events, activities, and institutions are put into practice as managers have developed their own knowledge and practices over time. Such practices become routine over time when managers encounter a similar problem, disequilibrium. Conventions such as the (")less than 35 rule,(") the (")80:20 rule,(") the call around, following suit, and trial and error are manifestations of the coping strategy for the hamstrung complexity in the hospitality industry. Human agency and its perception of reality within a specific context infuse meaning into business practices. The critical role of managers is recognized in making discount decisions as they use a collection of complex patterns in the lodging industry to perceive meaningful patterns in the environment to make a final judgment.The focus on the process of discount decision making allows for detecting how environmental stimuli are watched by managers with deeply held views. Managers use certain rules and patterns to complete their information search. Hotel managers place different values on the information attributes in making a discount choice. The average importance of an attribute represents how important it is to managers when making their discount choices. The results indicate that managers consider the booking window to be the most preferred information, followed by competitors' room rates, the potential for cancelation, and occupancy rate.A discount choice is the product of human agency and social forces over time, distinct from the rational model. Different hotel operation structures and human agencies seek to make a difference in the process of discount decision making. Hotels in Road Warriors, which are smaller in size, are not located near major attractions but seem to fill the need for leisure travelers passing by the highways. Less competition exists because the regional area does not serve as a main attraction. These hotels in Road Warriors thus place great importance on the booking window and potential for cancellation when considering offering a discount. If they do not see enough reservations in the short term and foresee the potential for cancellation, hotels in Road Warriors tend to make a discount choice. These hotels do not seem to indulge in implementing other pricing strategies, but do drop the rate. Hotels in Stars in the Universe, which are larger in size and affiliated with chains/brands, are located near the main attractions (e.g., beach, downtown, or convention center). Hotels in Stars in the Universe consider the booking window to be the most critical information, followed by competitors' room rates, occupancy rate, and potential for cancellation. The extent of how much time is left before an arrival date serves as the most important piece of information in making a discount choice. These hotels emphasize knowledge of competitors' room rates as these hotels have many competitors around and consistently compete for more market shares in the area. Moreover, human agency, mostly grounded in industry tenure and age, determines how managers process discount choices. Market Movers consists of more experienced and educated, older, and predominantly male experts. These general managers, assistant general managers, or revenue managers have gained knowledge and know-how during their extended experience in the industry. Managers in Market Movers focus importance on the booking window, followed by competitors' room rates, occupancy rate, and potential for cancellation. They monitor bookings ahead of time and consider offering a discount as the arrival nears. Managers in Market Movers also show great concern for competitors' room rates. They compare their rates to competitors' in order to ensure that their own rates do not go over competitors' room rates. Managers in Entourage are considered to be younger, less experienced, and less educated. Most managers in Entourage work in marketing/sales or front desk/operations and tend to follow and attend to the industry leaders. These novices try several trials and make errors along the way, but become rising stars in the industry when their trial-and-error approach succeeds. Entourage's discount choice is influenced more by the booking window, followed by potential for cancellation, competitors' room rates, and occupancy rate. Managers in Entourage consider the booking window to be the most critical in making a discount choice, and they act quickly to offer a discount when an arrival date nears. They tend to respond to immediate changes in booking; thus, the potential for cancellation determines the discount choice among Entourage managers. The main theoretical contribution of this study is to demonstrate that managerial frameworks based on a rational premise are not complete. These frameworks should be complemented with a human judgment framework, which provides a richer account of how managers in the lodging industry approach complex price-setting situations. Managerial discounting decision making often falls short of the purely rational model for managers and is bounded by nature. Managers are not always rational in compiling and assessing information leading to discounting that is compatible with the accessibility to information and the computational capacity. The human judgment process, discovered and examined in this study, provides a richer understanding of the process of discounting in the lodging industry. This process is featured by a non-conscious processing of information; the retrieval of the information is based on associations of patterns; the context in which this processing occurs is high paced; and the outcome of the decision is imbued with judgments.In terms of managerial implications, this study enables hotel managers to learn under what conditions other managers consider making discount choices. Information attributes such as the booking window and competitors' room rates are thought to be more valuable than other information. Managers should observe booking windows carefully when making a discount choice. Managers should pay close attention to bookings more in advance so that they detect discrepancies between forecasting and reality in a timely manner. If so, managers can make operational adjustments to rate strategies by controlling not only room rates, but also length of stay (LOS) and channels. Limitations and suggestions for future research are also discussed.
Show less
Date Issued: 2014
Identifier: CFE0005196, ucf:50645
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005196

Title: DEVELOPMENT OF THEORETICAL AND COMPUTATIONAL METHODS FOR FEW-BODY PROCESSES IN ULTRACOLD QUANTUM GASES.
Creator: Blandon, Juan, Kokoouline, Viatcheslav, University of Central Florida
Abstract / Description: We are developing theoretical and computational methods to study two related three-body processes in ultracold quantum gases: three-body resonances and three-body recombination. Three-body recombination causes the ultracold gas to heat up and atoms to leave the trap where they are confined. Therefore, it is an undesirable effect in the process of forming ultracold quantum gases. Metastable three-body states (resonances) are formed in the ultracold gas. When decaying they also give additional...
Show moreWe are developing theoretical and computational methods to study two related three-body processes in ultracold quantum gases: three-body resonances and three-body recombination. Three-body recombination causes the ultracold gas to heat up and atoms to leave the trap where they are confined. Therefore, it is an undesirable effect in the process of forming ultracold quantum gases. Metastable three-body states (resonances) are formed in the ultracold gas. When decaying they also give additional kinetic energy to the gas, that leads to the heating too. In addition, a reliable method to obtain three-body resonances would be useful in a number of problems in other fields of physics, for example, in models of metastable nuclei or to study dissociative recombination of H3 +. Our project consists of employing computer modeling to develop a method to obtain three-body resonances. The method uses a novel two-step diagonalization approach to solve the three-body Schrödinger equation. The approach employs the SVD method of Tolstikhin et al. coupled with a complex absorbing potential. We tested this method on a model system of three identical bosons with nucleon mass and compared it to the results of a previous study. This model can be employed to understand the 3He nucleus . We found one three-body bound state and four resonances. We are also studying Efimov resonances using a 4He-based model. In a system of identical spinless bosons, Efimov states are a series of loosely bound three-body states which begin to appear as the energy of the two-body bound state approaches zero . Although they were predicted 35 years ago, recent evidence of Efimov states found by Kraemer et al. in a gas of ultracold Cs atoms has sparked great interest by theorists and experimentalists. Efimov resonances are a kind of pre-dissociated Efimov trimer. To search for Efimov resonances we tune the diatom interaction potential, V(r): V(r) → λV(r) as Esry et al. did . We calculated the first two values of λ for which there is a "condensation" (infinite number) of Efimov states. They are λEfimov1 = 0.9765 and λEfimov2 = 6.834. We performed calculations for λ = 2.4, but found no evidence of Efimov resonances. For future work we plan to work with λ ≈ 4 and λ ≈ λEfimov2 where we might see d-wave and higher l-wave Efimov resonances. There is also a many-body project that forms part of this thesis and consists of a direct diagonalization of the Bogolyubov Hamiltonian, which describes elementary excitations of a gas of bosons interacting through a pairwise interaction. We would like to reproduce the corresponding energy spectrum. So far we have performed several convergence tests, but have not observed the desired energy spectrum. We show preliminary results.
Show less
Date Issued: 2006
Identifier: CFE0001320, ucf:47026
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001320

Title: DISCUSSION ON EFFECTIVE RESTORATION OF ORAL SPEECH USING VOICE CONVERSION TECHNIQUES BASED ON GAUSSIAN MIXTURE MODELING.
Creator: Alverio, Gustavo, Mikhael, Wasfy, University of Central Florida
Abstract / Description: Today's world consists of many ways to communicate information. One of the most effective ways to communicate is through the use of speech. Unfortunately many lose the ability to converse. This in turn leads to a large negative psychological impact. In addition, skills such as lecturing and singing must now be restored via other methods. The usage of text-to-speech synthesis has been a popular resolution of restoring the capability to use oral speech. Text to speech synthesizers convert...
Show moreToday's world consists of many ways to communicate information. One of the most effective ways to communicate is through the use of speech. Unfortunately many lose the ability to converse. This in turn leads to a large negative psychological impact. In addition, skills such as lecturing and singing must now be restored via other methods. The usage of text-to-speech synthesis has been a popular resolution of restoring the capability to use oral speech. Text to speech synthesizers convert text into speech. Although text to speech systems are useful, they only allow for few default voice selections that do not represent that of the user. In order to achieve total restoration, voice conversion must be introduced. Voice conversion is a method that adjusts a source voice to sound like a target voice. Voice conversion consists of a training and converting process. The training process is conducted by composing a speech corpus to be spoken by both source and target voice. The speech corpus should encompass a variety of speech sounds. Once training is finished, the conversion function is employed to transform the source voice into the target voice. Effectively, voice conversion allows for a speaker to sound like any other person. Therefore, voice conversion can be applied to alter the voice output of a text to speech system to produce the target voice. The thesis investigates how one approach, specifically the usage of voice conversion using Gaussian mixture modeling, can be applied to alter the voice output of a text to speech synthesis system. Researchers found that acceptable results can be obtained from using these methods. Although voice conversion and text to speech synthesis are effective in restoring voice, a sample of the speaker before voice loss must be used during the training process. Therefore it is vital that voice samples are made to combat voice loss.
Show less
Date Issued: 2007
Identifier: CFE0001793, ucf:47286
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001793

Title: FINDERS KEEPERS: A COMPARATIVE STUDY INVESTIGATING TEACHING THE FLORIDA RESEARCH PROCESS FINDS MODEL THROUGH THREE DIFFERENT APPROACHES AT THE ELEMENTARY SCHOOL LEVEL.
Creator: Serrell, Karen, Beile, Penny, University of Central Florida
Abstract / Description: The children's taunt "Finders Keepers, Losers Weepers" gives new credence to the information search process at the elementary school level. Children keep what they find, claim it as their own, and accept information without discernment or critique. This study examines the effectiveness of teaching information literacy skills through three different approaches. The first curricular approach uses direct instruction to teach children how to do research using the Florida Research Process...
Show moreThe children's taunt "Finders Keepers, Losers Weepers" gives new credence to the information search process at the elementary school level. Children keep what they find, claim it as their own, and accept information without discernment or critique. This study examines the effectiveness of teaching information literacy skills through three different approaches. The first curricular approach uses direct instruction to teach children how to do research using the Florida Research Process FINDS Model. The second approach pairs the FINDS Model with a unit of study that is related to classroom curriculum. The third approach examines the FINDS Model in conjunction with project learning, a constructivist model based on student interest. One hundred twenty- eight third grade students attending a public elementary school in Southwest Florida during the 2008-2009 school year participated in the study. A mixed-methods research approach was used to gather data. Quantitative data was collected with an information literacy pre and post test, and an anonymous media lessons' survey about student preferences. Qualitative data were gathered through a review of student work samples and student interviews. Statistically significant gains were found between the pre to post test scores for all three groups, however no statistically significant differences were found among groups. Although quantitative data did not reveal differences among the treatment groups, qualitative findings revealed that the group taught research skills through the connection to classroom curriculum approach performed better. Thus the findings of this study support existing research which proposes that the best practice for teaching research skills to young children is through a connection to classroom curriculum.
Show less
Date Issued: 2009
Identifier: CFE0002957, ucf:47963
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002957

Title: Reliability and Robustness Enhancement of Cooperative Vehicular Systems: A Bayesian Machine Learning Perspective.
Creator: Nourkhiz Mahjoub, Hossein, Pourmohammadi Fallah, Yaser, Vosoughi, Azadeh, Yuksel, Murat, Atia, George, Eluru, Naveen, University of Central Florida
Abstract / Description: Autonomous vehicles are expected to greatly transform the transportation domain in the near future. Some even envision that the human drivers may be fully replaced by automated systems. It is plausible to assume that at least a significant part of the driving task will be done by automated systems in not a distant future. Although we are observing a rapid advance towards this goal, which gradually pushes the traditional human-based driving toward more advanced autonomy levels, the full...
Show moreAutonomous vehicles are expected to greatly transform the transportation domain in the near future. Some even envision that the human drivers may be fully replaced by automated systems. It is plausible to assume that at least a significant part of the driving task will be done by automated systems in not a distant future. Although we are observing a rapid advance towards this goal, which gradually pushes the traditional human-based driving toward more advanced autonomy levels, the full autonomy concept still has a long way before being completely fulfilled and realized due to numerous technical and societal challenges. During this long transition phase, blended driving scenarios, composed of agents with different levels of autonomy, seems to be inevitable. Therefore, it is critical to design appropriate driving systems with different levels of intelligence in order to benefit all participants. Vehicular safety systems and their more advanced successors, i.e., Cooperative Vehicular Systems (CVS), have originated from this perspective. These systems aim to enhance the overall quality and performance of the current driving situation by incorporating the most advanced available technologies, ranging from on-board sensors such as radars, LiDARs, and cameras to other promising solutions e.g. Vehicle-to-Everything (V2X) communications. However, it is still challenging to attain the ideal anticipated benefits out of the cooperative vehicular systems, due to the inherent issues and challenges of their different components, such as sensors' failures in severe weather conditions or the poor performance of V2X technologies under dense communication channel loads. In this research we aim to address some of these challenges from a Bayesian Machine- Learning perspective, by proposing several novel ideas and solutions which facilitate the realization of more robust, reliable, and agile cooperative vehicular systems. More precisely, we have a two-fold contribution here. In one aspect, we have investigated the notion of Model-Based Communications (MBC) and demonstrated its effectiveness for V2X communication performance enhancement. This improvement is achieved due to the more intelligent communication strategy of MBC in comparison with the current state-of-the-art V2X technologies. Essentially, MBC proposes a conceptual change in the nature of the disseminated and shared information over the communication channel compared to what is being disseminated in current technologies. In the MBC framework, instead of sharing the raw dynamic information among the network agents, each agent shares the parameters of a stochastic forecasting model which represents its current and future behavior and updates these parameters as needed. This model sharing strategy enables the receivers to precisely predict the future behaviors of the transmitter even when the update frequency is very low. On the other hand, we have also proposed receiver-side solutions in order to enhance the CVS performance and reliability and mitigate the issues caused by imperfect communication and detection processes. The core concept for these solutions is incorporating other informative elements in the system to compensate for the lack of information which is lost during the imperfect communication or detection phases. For proof of concept, we have designed an adaptive FCW framework which considers the driver's feedbacks to the CVS system. This adaptive framework mitigates the negative impact of imperfectly received or detected information on system performance, using the inherent information of these feedbacks and responses. The effectiveness and superiority of this adaptive framework over traditional design has been demonstrated in this research.
Show less
Date Issued: 2019
Identifier: CFE0007845, ucf:52807
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007845

Title: MODIFICATIONS TO THE FUZZY-ARTMAP ALGORITHM FOR DISTRIBUTED LEARNING IN LARGE DATA SETS.
Creator: Castro, Jose R, Georgiopoulos, Michael, University of Central Florida
Abstract / Description: The Fuzzy-ARTMAP (FAM) algorithm is one of the premier neural network architectures for classification problems. FAM can learn on line and is usually faster than other neural network approaches. Nevertheless the learning time of FAM can slow down considerably when the size of the training set increases into the hundreds of thousands. We apply data partitioning and networkpartitioning to the FAM algorithm in a sequential and parallel settingto achieve better convergence time and to efficiently...
Show moreThe Fuzzy-ARTMAP (FAM) algorithm is one of the premier neural network architectures for classification problems. FAM can learn on line and is usually faster than other neural network approaches. Nevertheless the learning time of FAM can slow down considerably when the size of the training set increases into the hundreds of thousands. We apply data partitioning and networkpartitioning to the FAM algorithm in a sequential and parallel settingto achieve better convergence time and to efficiently train withlarge databases (hundreds of thousands of patterns).Our parallelization is implemented on a Beowulf clusters of workstations. Two data partitioning approaches and two networkpartitioning approaches are developed. Extensive testing of all the approaches is done on three large datasets (half a milliondata points). One of them is the Forest Covertype database from Blackard and the other two are artificially generated Gaussian data with different percentages of overlap between classes.Speedups in the data partitioning approach reached the order of the hundreds without having to invest in parallel computation. Speedups onthe network partitioning approach are close to linear on a cluster of workstations. Both methods allowed us to reduce the computation time of training the neural network in large databases from days to minutes. We prove formally that the workload balance of our network partitioning approaches will never be worse than an acceptable bound, and also demonstrate the correctness of these parallelization variants of FAM.
Show less
Date Issued: 2004
Identifier: CFE0000065, ucf:46092
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000065

Title: ACCOMPLISHMENT OF DUAL FOCUS IN EXPLORATION AND EXPLOITATION: THE INFLUENTIAL ROLE OF THE CUSTOMER RELATIONSHIP MANAGEMENT (CRM) PROCESS.
Creator: Tinoco, Janet, Ganesh, Jai, University of Central Florida
Abstract / Description: Organizations that can successfully develop both radical and incremental innovations positively impact sustained competitive advantage, dramatically improving their chances of survival and success in both dynamic and stable environments (Han et al. 2001; Tushman and O'Reilly 1996). Experimentation and radical innovation are mandatory knowledge assets for competitive play in emerging markets, but efficiency and incremental innovation are essential for mature markets (He and Wong 2004;...
Show moreOrganizations that can successfully develop both radical and incremental innovations positively impact sustained competitive advantage, dramatically improving their chances of survival and success in both dynamic and stable environments (Han et al. 2001; Tushman and O'Reilly 1996). Experimentation and radical innovation are mandatory knowledge assets for competitive play in emerging markets, but efficiency and incremental innovation are essential for mature markets (He and Wong 2004; Tushman and O'Reilly 1996). The attainment of dual focus between radical and incremental innovation is challenging and calls for organizational architectures of sometimes conflicting processes, structure, and culture (cf, Tushman and O'Reilly 1996; Wind and Mahajan 1997). While prior research has investigated the structural and cultural determinants (Duncan 1976; Gibson and Birkenshaw 2004), there is a significant lack of research addressing the third major element of business processes. Without winning business processes in place that influence both exploration and exploitation, a successful portfolio mix of radical and incremental product innovations that maximize customer value and benefits will not be fully realized, and firm performance will suffer. Through core business processes, marketing's role and influence is significant in increasing customer value creation in the resulting product innovations. By mapping the "inside-out" and "outside-in" processes of a market-driven organization (Day 1994) into the Srivastava et al. (1999) core business process framework, this dissertation develops and tests a model of business process influence on dual focus in innovation strategies in the context of the high technology manufacturing environment. Each of these processes is critical in generating maximum customer value and is an explicit input into strategic choices and decisions (Srivastava et al. 1999). Specifically, it is argued and proposed that the Product Development Management (PDM) process, comprised of the processes of market experimentation, technology monitoring, and technology competence, predominantly influences exploration while the Supply Chain Management (SCM) process, comprised of the processes of channel bonding and quality process management, predominantly influences exploitation. The Customer Relationship Management (CRM) process, encompassing the processes of lead user collaboration, competitor benchmarking, and current customer knowledge process, acts as a moderator to add dual focus to these extremes by interacting with PDM processes to enhance exploitation and with SCM processes to enhance exploration. Furthermore, it is proposed that firms successfully achieving a dual focus have greater firm performance than firms entrenched in either extreme. Hypotheses were tested with data collected from a nationwide sample of high technology manufacturers. The results largely supported the main effect hypotheses of the PDM processes and SCM processes on exploration and exploitation. Additionally, the hypothesis of a positive interaction between exploration and exploitation on firm performance was also supported, however no visible support was garnered for the moderating impacts of CRM processes on PDM and SCM processes as hypothesized. Post hoc analyses were performed, bringing additional insight into dual focus based on the successful implementation of opposing businesses processes. Specifically, dual focus firms were shown to have multiple processes in place that impact both types of innovation strategies and that these firms implement these processes to a greater extent than those firms operating in the more extreme positions. Academic and managerial implications are discussed, as well as study limitations and exciting future research directions.
Show less
Date Issued: 2007
Identifier: CFE0001573, ucf:47114
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001573

Title: A METHOD OF CONTENT-BASED IMAGE RETRIEVAL FOR THE GENERATION OF IMAGE MOSAICS.
Creator: Snead, Michael, Richie, Samuel, University of Central Florida
Abstract / Description: An image mosaic is an artistic work that uses a number of smaller images creatively combined together to form another larger image. Each building block image, or tessera, has its own distinctive and meaningful content, but when viewed from a distance the tesserae come together to form an aesthetically pleasing montage. This work presents the design and implementation of MosaiX, a computer software system that generates these image mosaics automatically. To control the image mosaic creation...
Show moreAn image mosaic is an artistic work that uses a number of smaller images creatively combined together to form another larger image. Each building block image, or tessera, has its own distinctive and meaningful content, but when viewed from a distance the tesserae come together to form an aesthetically pleasing montage. This work presents the design and implementation of MosaiX, a computer software system that generates these image mosaics automatically. To control the image mosaic creation process, several parameters are used within the system. Each parameter affects the overall mosaic quality, as well as required processing time, in its own unique way. A detailed analysis is performed to evaluate each parameter individually. Additionally, this work proposes two novel ways by which to evaluate the quality of an image mosaic in a quantitative way. One method focuses on the perceptual color accuracy of the mosaic reproduction, while the other concentrates on edge replication. Both measures include preprocessing to take into account the unique visual features present in an image mosaic. Doing so minimizes quality penalization due the inherent properties of an image mosaic that make them visually appealing.
Show less
Date Issued: 2007
Identifier: CFE0001585, ucf:47115
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001585

Title: OPTIMIZING THE HIGH DYNAMIC RANGE IMAGING PIPELINE.
Creator: Akyuz, Ahmet, Reinhard, Erik, University of Central Florida
Abstract / Description: High dynamic range (HDR) imaging is a rapidly growing field in computer graphics and image processing. It allows capture, storage, processing, and display of photographic information within a scene-referred framework. The HDR imaging pipeline consists of the major steps an HDR image is expected to go through from capture to display. It involves various techniques to create HDR images, pixel encodings and file formats for storage, tone mapping for display on conventional display devices and...
Show moreHigh dynamic range (HDR) imaging is a rapidly growing field in computer graphics and image processing. It allows capture, storage, processing, and display of photographic information within a scene-referred framework. The HDR imaging pipeline consists of the major steps an HDR image is expected to go through from capture to display. It involves various techniques to create HDR images, pixel encodings and file formats for storage, tone mapping for display on conventional display devices and direct display on HDR capable screens. Each of these stages have important open problems, which need to be addressed for a smoother transition to an HDR imaging pipeline. We addressed some of these important problems such as noise reduction in HDR imagery, preservation of color appearance, validation of tone mapping operators, and image display on HDR monitors. The aim of this thesis is thus, to present our findings and describe the research we have conducted within the framework of optimizing the HDR imaging pipeline.
Show less
Date Issued: 2007
Identifier: CFE0001875, ucf:47404
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001875

Title: AUTONOMOUS ROBOTIC AUTOMATION SYSTEMWITH VISION FEEDBACK.
Creator: Rosino, Jeffery, Qu, Zhihua, University of Central Florida
Abstract / Description: In this thesis, a full design, development and application of an autonomous robotic automation system using vision feedback is performed. To realize this system, a cylindrical manipulator configuration is implemented, using a personal computer (PC) based PID controller from National Instruments. Full autonomous control will be achieved via a programmable human machine interface (HMI) developed on a PC using Borland C++ Builder. The vision feedback position control is accomplished using an...
Show moreIn this thesis, a full design, development and application of an autonomous robotic automation system using vision feedback is performed. To realize this system, a cylindrical manipulator configuration is implemented, using a personal computer (PC) based PID controller from National Instruments. Full autonomous control will be achieved via a programmable human machine interface (HMI) developed on a PC using Borland C++ Builder. The vision feedback position control is accomplished using an ordinary "off-the-shelf" web camera. The manuscript is organized as follows; After Chapter 1, an introduction to automation history and its role in the manufacturing industry, Chapter 2 discusses and outlines the development of the robotic kinematics and dynamics of the system. A control strategy is also developed and simulated in this chapter. Chapter 3 discusses color image processing and shows the development of the algorithm used for the vision feedback position control. Chapter 4 outlines the system development, which includes the hardware and software. Chapter 5 concludes with a summary, and improvement section. The process used as a basis for the design and development of this thesis of this thesis topic was constructed from a manual capacitor orientation check test station. A more detailed definition and objective is presented in the introduction.
Show less
Date Issued: 2004
Identifier: CFE0000277, ucf:46220
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000277

Title: A STUDY OF SEMANTIC PROCESSING PERFORMANCE.
Creator: Dever, Daryn A, Szalma, James, Neigel, Alexis, University of Central Florida
Abstract / Description: Examining the role of individual differences, especially variations in human motivation, in vigilance tasks will result in a better understanding of sustained semantic attention and processing, which has, to date, received limited study in the literature (see Fraulini, Hancock, Neigel, Claypoole, & Szalma, 2017; Epling, Russell, & Helton, 2016; Thomson et al., 2016). This present study seeks to understand how individual differences in intrinsic motivation affect performance in a short...
Show moreExamining the role of individual differences, especially variations in human motivation, in vigilance tasks will result in a better understanding of sustained semantic attention and processing, which has, to date, received limited study in the literature (see Fraulini, Hancock, Neigel, Claypoole, & Szalma, 2017; Epling, Russell, & Helton, 2016; Thomson et al., 2016). This present study seeks to understand how individual differences in intrinsic motivation affect performance in a short semantic vigilance task. Performance across two conditions (lure vs. standard condition) were compared in the present study of 79 undergraduate students at the University of Central Florida. The results indicated significant main effects of intrinsic motivation on pre- and post-task stress factors, workload, and performance measures, which included correct detections, false alarms, and response time. Sensitivity and response bias, which are indices of signal detection theory, were also examined in the present study. Intrinsic motivation influenced sensitivity, but not response bias, which was affected by period on watch. The theoretical and practical implications of this research are also discussed.
Show less
Date Issued: 2017
Identifier: CFH2000245, ucf:45984
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH2000245

Title: DECREASING ALCOHOL USE AMONG HIGH SCHOOL STUDENTS BY CHALLENGING ALCOHOL EXPECTANCIES.
Creator: Cruz, Iris, Dunn, Michael, University of Central Florida
Abstract / Description: Altering alcohol expectancies has reduced alcohol use among college students and may lead to successful prevention of alcohol use among high school students. We randomly assigned 379 12th-grade students to an expectancy challenge, traditional alcohol information, or control condition, and used Individual Differences Scaling to map expectancies into memory network format with Preference Mapping to model likely paths of association. After expectancy and traditional alcohol interventions, higher...
Show moreAltering alcohol expectancies has reduced alcohol use among college students and may lead to successful prevention of alcohol use among high school students. We randomly assigned 379 12th-grade students to an expectancy challenge, traditional alcohol information, or control condition, and used Individual Differences Scaling to map expectancies into memory network format with Preference Mapping to model likely paths of association. After expectancy and traditional alcohol interventions, higher drinking male participants exhibited a greater likelihood to associate alcohol use with negative and sedating consequences and a decreased likelihood to associate alcohol with positive and arousing consequences. Drinking decreases paralleled the magnitude of changes in their likely path of expectancy activation. Children and adults who emphasize negative and sedating effects have been found to be less likely to use alcohol. Therefore, expectancy challenge interventions that have been successful at modifying expectancies and subsequently decreasing alcohol consumption among heavy drinking college students may be useful in the development of prevention curricula for high school students.
Show less
Date Issued: 2006
Identifier: CFE0001232, ucf:46887
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001232

natural language processing (5)	+ -
Image Processing (4)	+ -
process (4)	+ -
processing (4)	+ -
Image processing (3)	+ -

Musical Theatre (3)	+ -
Optical data processing (3)	+ -
Performance (3)	+ -
Signal Processing (3)	+ -
information processing (3)	+ -
Academic (2)	+ -
Academic -- Engineering (2)	+ -
Actor's Process (2)	+ -
Big Data (2)	+ -
Coherence (2)	+ -
Digital Signal Processing (2)	+ -
Discrete Event Simulation (2)	+ -
Dissertations (2)	+ -
ECG (2)	+ -
Engineering -- Dissertations (2)	+ -
Entanglement (2)	+ -
Image processing -- Digital techniques (2)	+ -
Imaging systems in meteorology (2)	+ -
Information Processing (2)	+ -
Lapine (2)	+ -
Machine Learning (2)	+ -
Military art and science -- Data processing (2)	+ -
Modeling (2)	+ -
NASA (2)	+ -
Optical Fiber Communication (2)	+ -

ETD Collection (167)	+ -
Honors Collection (10)	+ -

English (176)	+ -
Engilsh (1)	+ -

University of Central Florida (159)	+ -
Engineering (15)	+ -
Turgut, Damla (6)	+ -
Atia, George (5)	+ -
Bowers, Clint (5)	+ -

Search In

Pages

Pages

Sort Results By:

Narrow results by:

Topical Subject

Collection

Type of Resource

Language

Creator

Format

Owner