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 Title
 Stability of an elliptical vortex in a timedependent strain field.
 Creator
 Marshall, Marilyn P., Florida Atlantic University, Dhanak, Manhar R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

A theoretical study of the stability of twodimensional elliptical vortices in a timedependent, periodically varying external straining flow was conducted. The mean value of the oscillating straining flow was chosen so that the vortex would be stationary in the absence of fluctuations of the external field about the mean. If the frequency of straining is near to the natural frequency of the vortex for smallamplitude oscillations of the vortex core, so that the vortex is forced near its...
Show moreA theoretical study of the stability of twodimensional elliptical vortices in a timedependent, periodically varying external straining flow was conducted. The mean value of the oscillating straining flow was chosen so that the vortex would be stationary in the absence of fluctuations of the external field about the mean. If the frequency of straining is near to the natural frequency of the vortex for smallamplitude oscillations of the vortex core, so that the vortex is forced near its natural frequency, a resonance occurs such that the aspect ratio of the elliptical core boundary initially oscillates with an amplitude that increases linearly with time. After an initial period of growth, the aspect ratio will either follow a bounded limit cycle at large time or it will elongate exponentially with time. The nonlinear evolution of the vortex at large time is studied numerically, and distinct regions of behavior in the parameter space for the vortex are obtained.
Show less  Date Issued
 1992
 PURL
 http://purl.flvc.org/fcla/dt/14817
 Subject Headings
 VortexMotion, Fluid dynamicsMathematical models
 Format
 Document (PDF)
 Title
 Stochastical aspects of neuronal activity, neural networks, and communication.
 Creator
 De Groff, Dolores F., Florida Atlantic University, Neelakanta, Perambur S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
 Abstract/Description

By revisiting the popular framework of depicting neuronal (collective) activities as analogous to Ising's spinglass theory of interacting magnetic spins, the contradictions that coexist with such an analogy are extracted and discussed. To alleviate such contradictions, an alternative strategy of equating the neuronal interactions to the partially anisotropic nematic phase of disorder pertaining to liquid crystals is proposed. Hence, the extent of anisotropy in the neuronal system, quantified...
Show moreBy revisiting the popular framework of depicting neuronal (collective) activities as analogous to Ising's spinglass theory of interacting magnetic spins, the contradictions that coexist with such an analogy are extracted and discussed. To alleviate such contradictions, an alternative strategy of equating the neuronal interactions to the partially anisotropic nematic phase of disorder pertaining to liquid crystals is proposed. Hence, the extent of anisotropy in the neuronal system, quantified in terms of an orderfunction, is specified to elucidate the nonlinear squashing action of the inputoutput relations in a neuronal cell. The relevant approach thereof, is based on Langevin's theory considerations as applied to dipole molecules. Further, in view of the stochastical properties due to the inherent disorder associated with the neuronal assembly, the progression of statetransitions across the interconnected cells is modeled as a momentum flow relevant to particle dynamics. Hence, corresponding wave mechanics attributions of such a collective movement of statetransition activity are described in terms of a probabilistic wave function. Lastly, the stochastical aspects of noiseperturbed neuronal dynamics are studied via FokkerPlanck equation representing the Langevintype relaxational (nonlinear) process associated with the neuronal states. On each of these topics portraying the stochastical characteristics of the neuronal assembly and its activities, newer and/or more exploratory inferences are made, logical conclusions are enumerated and relevant discussions are presented along with the scope for future research to be pursued.
Show less  Date Issued
 1993
 PURL
 http://purl.flvc.org/fcla/dt/12326
 Subject Headings
 NeuronsMathematical models, Stochastic processes, Neural networks (Computer science)
 Format
 Document (PDF)
 Title
 Transforming directed graphs into uncertain rules.
 Creator
 Lantigua, Jose Salvador., Florida Atlantic University, Hoffman, Frederick, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
 Abstract/Description

The intent of this thesis is to show how rule structures can be derived from influence diagrams and how these structures can be mapped to existing rulebased shell paradigms. We shall demonstrate this mapping with an existing shell having the Evidence (E) > Hypothesis (H), Certainty Factor (CF) paradigm structure. Influence diagrams are graphical representations of hypothesis to evidence, directed forms of Bayesian influence networks. These allow for inferencing about both diagnostic and...
Show moreThe intent of this thesis is to show how rule structures can be derived from influence diagrams and how these structures can be mapped to existing rulebased shell paradigms. We shall demonstrate this mapping with an existing shell having the Evidence (E) > Hypothesis (H), Certainty Factor (CF) paradigm structure. Influence diagrams are graphical representations of hypothesis to evidence, directed forms of Bayesian influence networks. These allow for inferencing about both diagnostic and predictive (or causal) behavior based on uncertain evidence. We show how this can be implemented through a Probability (P) to CF mapping algorithm and a ruleset conflict resolution methodology. The thesis contains a discussion about the application of probabilistic semantics from Bayesian networks and of decision theory, to derive qualitative assertions about the likelihood of an occurrence; the sensitivity of a conclusion; and other indicators of usefulness. We show an example of this type of capability by the addition of a probability range function for the premise clause in our shell's rule structure.
Show less  Date Issued
 1989
 PURL
 http://purl.flvc.org/fcla/dt/14570
 Subject Headings
 DecisionmakingMathematical models, Probabilities, Expert systems (Computer science)
 Format
 Document (PDF)
 Title
 THE USE OF CERTAINTY EQUIVALENCE FOR LOCATION AND ECONOMIC GROWTH DECISIONS.
 Creator
 WONSETLER, ELIZABETH ANN., Florida Atlantic University, Scheidell, John M., College of Business, Department of Economics
 Abstract/Description

This study was prepared to analyze the use of the firstperiod certainty equivalence procedure in location decisions. Certainty equivalence is a mathematical technique which explicitly incorporates probablistic uncertainty in the decision making process. The feasible location of an international jetport which would service the South Florida region is used to illustrate this decision making technique.
 Date Issued
 1972
 PURL
 http://purl.flvc.org/fcla/dt/13473
 Subject Headings
 DecisionmakingMathematical models, Uncertainty (Information theory)
 Format
 Document (PDF)
 Title
 Transfer effects of a high school computer programming course on mathematical modeling, procedural comprehension, and verbal problem solution.
 Creator
 Bernardo, Madeline Ann, Florida Atlantic University, Morris, John D., Weppner, Daniel B.
 Abstract/Description

Computers are becoming an integral part of our high school curriculum. Students use computers for computerassisted instruction (CAI), word processing, spreadsheet and database applications, and computer programming. It is important to know the cognitive effects of each mode of computer use. The purpose of this study was to investigate transfer effects of a high school BASIC programming course on students' skills in mathematical modeling, procedural comprehension, and verbal problem solution....
Show moreComputers are becoming an integral part of our high school curriculum. Students use computers for computerassisted instruction (CAI), word processing, spreadsheet and database applications, and computer programming. It is important to know the cognitive effects of each mode of computer use. The purpose of this study was to investigate transfer effects of a high school BASIC programming course on students' skills in mathematical modeling, procedural comprehension, and verbal problem solution. The sample consisted of 44 BASIC I students, 44 computer literacy students, and 44 students who had no computer training. Groups were matched on years of mathematics and on the grade received in the last mathematics course taken. Pretests and posttests were administered. Results indicated no significant differences in scores among groups for mathematical modeling or procedural comprehension; however, a significant difference was found among groups for verbal problem solution. The BASIC group scored significantly higher than the computer literacy group and the group with no exposure (p < .01). Auxiliary hypotheses examined possible interactions of group with gender, student level, prior grade received in mathematics, and years of high school mathematics. Significant main effects were found for both prior grade (p < .05) and years of mathematics (p < .05) with achievement directly related to excellence of grades and magnitude of coursework. Neither gender x treatment interaction, nor gender alone was found to be a significant source of score variance. Although the variance caused by student grade level was not significant, a significant interaction was found between group membership and grade level with respect to verbal problems. Sophomores in the literacy group scored higher than did sophomores in the nonexposure group; juniors in the nonexposure group scored higher than juniors in the computer literacy group. Suggestions for future research include studying effects (a) over an entire district, (b) on lower level mathematics students, and (c) on lower socioeconomic groups. Recommendations for computer education include teaching algebraic problem solving by computer and exposure of programming coursework to a wider population.
Show less  Date Issued
 1992
 PURL
 http://purl.flvc.org/fcla/dt/12302
 Subject Headings
 Computerassisted instruction, Verbal learning, Mathematical models, Comprehension
 Format
 Document (PDF)
 Title
 Dynamics of twoactor cooperation–competition conflict models.
 Creator
 Liebovitch, Larry S., Naudot, Vincent, Vallacher, Robin R., Nowak, Andrzej, BuiWrzosinska, Lan, Coleman, Peter T.
 Date Issued
 20081101
 PURL
 http://purl.flvc.org/fau/165475
 Subject Headings
 Nonlinear theories, Social systemsMathematical models, Conflict management, Cooperativeness, Differential equations, Competition, DynamicsMathematical models
 Format
 Document (PDF)
 Title
 Selforganizing dynamics of coupled map systems.
 Creator
 Liebovitch, Larry S., Zochowski, Michal
 Date Issued
 199903
 PURL
 http://purl.flvc.org/fau/165481
 Subject Headings
 DynamicsMathematical models, Chaotic behavior in systems, Selforganizing maps, Selforganizing systemsMathematical models
 Format
 Document (PDF)
 Title
 Nonlinearity and entrepreneurship.
 Creator
 Pflaum, Blaine., Harriet L. Wilkes Honors College
 Abstract/Description

Entrepreneurship occupies a curious place in economic theory. On one hand, the importance of entrepreneurship is widely recognized, particularly as it pertains to economic growth. However, the entrepreneur lacks a broadly accepted economic theory, and suffers from a dearth of literature on the subject. We believe that this is due to economics' heavy reliance on linear mathematical theory. In this thesis, we use nonlinear mathematics to construct a model of the entrepreneur that captures the...
Show moreEntrepreneurship occupies a curious place in economic theory. On one hand, the importance of entrepreneurship is widely recognized, particularly as it pertains to economic growth. However, the entrepreneur lacks a broadly accepted economic theory, and suffers from a dearth of literature on the subject. We believe that this is due to economics' heavy reliance on linear mathematical theory. In this thesis, we use nonlinear mathematics to construct a model of the entrepreneur that captures the sudden destabilization of a steady state, the unpredictability of a creative action, the possibility of entrepreneurial failure, and sensitivity to small changes in environment.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/FAU/3335458
 Subject Headings
 Economics, Mathematical, Nonlinear theories, Entrepreneurship, Mathematical models, New business enterprises, Econometric models, Statics and dynamics (Social sciences)
 Format
 Document (PDF)
 Title
 Analysis of ship hull and plate vibrations caused by wave forces.
 Creator
 Lakitosh, Fnu, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

In the present dissertation, the hydrodynamic and hydroelastic characteristics of ship hull and plate vibrations are analyzed using theoretical and numerical methods. The wave forces are determined using a suite of methods which include the FroudeKrylov method for incident wave forces, Wagner's method and ABS rules for the slamming wave force, and numerical methods for nonlinear wave radiation forces. Finite difference methods are developed to determine the wave forced vibrations of ship...
Show moreIn the present dissertation, the hydrodynamic and hydroelastic characteristics of ship hull and plate vibrations are analyzed using theoretical and numerical methods. The wave forces are determined using a suite of methods which include the FroudeKrylov method for incident wave forces, Wagner's method and ABS rules for the slamming wave force, and numerical methods for nonlinear wave radiation forces. Finite difference methods are developed to determine the wave forced vibrations of ship hull plates which are modeled using a range of plate theories including nonlinear plate theory with and without material damping and orthotropic plate theory for stiffened hull plates. For small amplitude deformation of thin plates, a semitheoretical superposition method is used to determine the free and forced vibrations. The transient ship hull vibration due to whipping is also analyzed using the finite difference method. Results, in the form of deformations and stress distributions, are obtained for a range of scantling and wave parameters to identify key parameters to consider in ship structural design.
Show less  Date Issued
 2012
 PURL
 http://purl.flvc.org/FAU/3342196
 Subject Headings
 Vibration (Marine engineering), Hulls (Naval architecture), Ships, Hydraulic impact, Ocean waves, Mathematical models, Fluid dynamics, Mathematical models
 Format
 Document (PDF)
 Title
 Fatigue modeling of composite ocean current turbine blade.
 Creator
 Akram, Mohammad Wasim, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The success of harnessing energy from ocean current will require a reliable structural design of turbine blade that is used for energy extraction. In this study we are particularly focusing on the fatigue life of a 3m length ocean current turbine blade. The blade consists of sandwich construction having polymeric foam as core, and carbon/epoxy as face sheet. Repetitive loads (Fatigue) on the blade have been formulated from the randomness of the ocean current associated with turbulence and...
Show moreThe success of harnessing energy from ocean current will require a reliable structural design of turbine blade that is used for energy extraction. In this study we are particularly focusing on the fatigue life of a 3m length ocean current turbine blade. The blade consists of sandwich construction having polymeric foam as core, and carbon/epoxy as face sheet. Repetitive loads (Fatigue) on the blade have been formulated from the randomness of the ocean current associated with turbulence and also from velocity shear. These varying forces will cause a cyclic variation of bending and shear stresses subjecting to the blade to fatigue. Rainflow Counting algorithm has been used to count the number of cycles within a specific mean and amplitude that will act on the blade from random loading data. Finite Element code ANSYS has been used to develop an SN diagram with a frequency of 1 Hz and loading ratio 0.1 Number of specific load cycles from Rainflow Counting in conjunction with SN diagram from ANSYS has been utilized to calculate fatigue damage up to 30 years by PalmgrenMiner's linear hypothesis.
Show less  Date Issued
 2010
 PURL
 http://purl.flvc.org/FAU/2867332
 Subject Headings
 Turbines, Blades, Materials, Fatigue, Marine turbines, Mathematical models, Structural dynamics, Composite materials, Mathematical models, Sandwich construction, Fatigue
 Format
 Document (PDF)
 Title
 Numerical Assessment of EddyViscosity Turbulence Models of an AxialFlow Turbine at a Low Reynolds Number.
 Creator
 Estrada, Nick Dagoberto, Moslemian, Davood, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The flow field behavior of axial flow turbines is of great importance, especially in modern designs that may operate at a low Reynolds number. At these low Reynolds numbers, the efficiency loss is significantly augmented compared to higher Reynolds number flows. A detailed incompressible numerical study of a single stage axialflow turbine at a low Reynolds number is investigated with the use of multiple eddyviscosity turbulence models. The study includes epistemic uncertainty quantification...
Show moreThe flow field behavior of axial flow turbines is of great importance, especially in modern designs that may operate at a low Reynolds number. At these low Reynolds numbers, the efficiency loss is significantly augmented compared to higher Reynolds number flows. A detailed incompressible numerical study of a single stage axialflow turbine at a low Reynolds number is investigated with the use of multiple eddyviscosity turbulence models. The study includes epistemic uncertainty quantification as a form of numerical error estimation. The numerical results show good qualitative and quantitative agreement with experimental data. It was found that the shear stress transport (SST) k  ω turbulence model with rotation/curvature correction and inclusion of transition modeling is most capable at predicting the mean velocity distribution, which is further enhanced when the URANS formulation is employed. However, all the cases indicate a large variation in the prediction of the rootmeansquared of the turbulent velocity fluctuations.
Show less  Date Issued
 2016
 PURL
 http://purl.flvc.org/fau/fd/FA00004587, http://purl.flvc.org/fau/fd/FA00004587
 Subject Headings
 TurbomachinesFluid dynamics., TurbulenceMathematical models., Structural dynamics., Viscous flowMathematical models., Reynolds number., Axial flow.
 Format
 Document (PDF)
 Title
 Predicting the flow & noise of a rotor in a turbulent boundary layer using an actuator disk – Rans approach.
 Creator
 Buono, Armand C., Glegg, Stewart A. L., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

The numerical method presented in this study attempts to predict the mean, nonuniform flow field upstream of a propeller partially immersed in a thick turbulent boundary layer with an actuator disk using CFD based on RANS in ANSYS FLUENT. Three different configurations, involving an infinitely thin actuator disk in the freestream (Configuration 1), an actuator disk near a wall with a turbulent boundary layer (Configuration 2), and an actuator disk with a hub near a wall with a turbulent...
Show moreThe numerical method presented in this study attempts to predict the mean, nonuniform flow field upstream of a propeller partially immersed in a thick turbulent boundary layer with an actuator disk using CFD based on RANS in ANSYS FLUENT. Three different configurations, involving an infinitely thin actuator disk in the freestream (Configuration 1), an actuator disk near a wall with a turbulent boundary layer (Configuration 2), and an actuator disk with a hub near a wall with a turbulent boundary layer (Configuration 3), were analyzed for a variety of advance ratios ranging from J = 0.48 to J =1.44. CFD results are shown to be in agreement with previous works and validated with experimental data of reverse flow occurring within the boundary layer above the flat plate upstream of a rotor in the Virginia Tech’s Stability Wind Tunnel facility. Results from Configuration 3 will be used in future aeroacoustic computations.
Show less  Date Issued
 2014
 PURL
 http://purl.flvc.org/fau/fd/FA00004269, http://purl.flvc.org/fau/fd/FA00004269
 Subject Headings
 Aeroelasticity, Computational fluid dynamics, Fluid dynamic measurements, Fluid mechanics  Mathematical models, Turbomachines  Fluid dynamics, Turbulence  Mathematical models
 Format
 Document (PDF)
 Title
 The Effect of Stereoscopic Cues on Multiple Object Tracking in a 3D Virtual Environment.
 Creator
 Oliveira, Steven Milanez, Barenholtz, Elan, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Psychology
 Abstract/Description

Research on Multiple Object Tracking (MOT) has typically involved 2D displays where stimuli move in a single depth plane. However, under natural conditions, objects move in 3D which adds complexity to tracking. According to the spatial interference model, tracked objects have an inhibitory surround that when crossed causes tracking errors. How do these inhibitory fields translate to 3D space? Does multiple object tracking operate on a 2D planar projection, or is it in fact 3D? To investigate...
Show moreResearch on Multiple Object Tracking (MOT) has typically involved 2D displays where stimuli move in a single depth plane. However, under natural conditions, objects move in 3D which adds complexity to tracking. According to the spatial interference model, tracked objects have an inhibitory surround that when crossed causes tracking errors. How do these inhibitory fields translate to 3D space? Does multiple object tracking operate on a 2D planar projection, or is it in fact 3D? To investigate this, we used a fully immersive virtualreality environment where participants were required to track 1 to 4 moving objects. We compared performance to a condition where participants viewed the same stimuli on a computer screen with monocular depth cues. Results suggest that participants were more accurate in the VR condition than the computer screen condition. This demonstrates interference is negligent when the objects are spatially distant, yet proximate within the 2D projection.
Show less  Date Issued
 2017
 PURL
 http://purl.flvc.org/fau/fd/FA00004943, http://purl.flvc.org/fau/fd/FA00004943
 Subject Headings
 Pattern perception., Virtual reality., Interactive multimedia., Computer simulation., Computer visionMathematical models., Automatic trackingMathematical models.
 Format
 Document (PDF)
 Title
 Wave Ship Interaction in Transforming Seas.
 Creator
 Gong, Fuxian, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
 Abstract/Description

In nearshore transforming seas, as waves approach the shoreline, wave shoaling and sometimes wave breaking take place due to the decreasing water depth. When a ship advances through the transforming seas, the ship body and waves interact with each other substantially and can lead to unknown motions of the ship hull. The physical process of how the wave transforms in the surf zone and how the vehicle actually behaves when it passes through the transforming seas is a complicated issue that...
Show moreIn nearshore transforming seas, as waves approach the shoreline, wave shoaling and sometimes wave breaking take place due to the decreasing water depth. When a ship advances through the transforming seas, the ship body and waves interact with each other substantially and can lead to unknown motions of the ship hull. The physical process of how the wave transforms in the surf zone and how the vehicle actually behaves when it passes through the transforming seas is a complicated issue that triggers considerable research interest. The goal of my research is to characterize the dynamics of a highspeed surface ship model in transforming seas through a parametric numerical study of the shipwave interactions. In this study, the vehicle of interest is a surface effect ship (SES) and we aim to contribute to developing a methodology for simulating the transforming wave environment, including wave breaking, and its interactions with the SES. The thesis work uses a commercial software package ANSYS Fluent to generate numerical waves and model the interface between water and air using the volume of fluid (VoF) method. A ship motion solver and the dynamic mesh are used to enable the modeled ship to perform three degreeoffreedom (DoF) motion and the nearregion of the ship hull to deform as well as remesh. Nonconformal meshes with hybrid compositions of different cell types and various grid sizes are used in the simulations for different purposes. Five userdefined functions (UDFs) are dynamically linked with the flow solver to incorporates ship/grid motions, wave damping and output of the numerical results. A series of steps were taken sequentially: 1) validation for ship motions including simulation of a static Wigley hull under steady flows to compare against previous experimental results by other researchers, and the comparison between the static SES model under steady flows and the moving SES model advancing in the calm water; 2) study of the ship with 3 DoF advancing in calm water of both constant depth and varying depth; 3) validation for numerical waves, including predictions of numerically progressive waves in both a regular tank and a tank with a sloped fringing reef to compare with theoretical and experimental results, respectively; 4) investigation of the transforming characteristics of the wave traveling over the sloped fringing reef, which mimics the nearshore wave environment and a study of the dynamics of the SES through transforming waves. We find that the flow solver used in this study reliably models the wave profiles along the ship hull. The comparison between a static SES in a current and a moving SES in calm water at the same Froude number shows that although the velocity fields around the vehicle are significantly different, the wave profiles inside and outside the rigid cushion of the vehicle are similar and the resistance force experienced by the vehicle in the two scenarios agree well over time. We conducted five numerical simulations of the vehicle traveling from shallow water to deep water across the transition zone for different Froude numbers. From the results, we find that as the Froude number increases, the wave resistance force on the vehicle becomes larger in both shallow water and deep water. In addition, the overall mean resistance force experienced by the vehicle over the whole trip increases with the Froude number. Statistical analysis of the wave motions suggests that the energy flux decreases dramatically in the onshore direction as the waves break. The more severe the wavebreaking process, the greater the decrease in energy flux. Both the increase of Froude number and the wave steepness apparently increase the resistance force on the vehicle in the shallow water. This thesis work captures the impact of the transforming characteristics of the waves and closely replicates the behavior of how waves interact with a ship in transforming seas through numerical modeling and simulation.
Show less  Date Issued
 2017
 PURL
 http://purl.flvc.org/fau/fd/FA00004916, http://purl.flvc.org/fau/fd/FA00004916
 Subject Headings
 HydrodynamicsMathematical models., Fluid dynamicsMathematical models., Ocean wavesMeasurement., Water wavesMeasurement., Coastal engineering.
 Format
 Document (PDF)
 Title
 Kicks and Maps A different Approach to Modeling Biological Systems.
 Creator
 Ippolito, Stephen Anthony, Naudot, Vincent, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
 Abstract/Description

Modeling a biological systems, is a cyclic process which involves constructing a model from current theory and beliefs and then validating that model against the data. If the data does not match, qualitatively or quantitatively then there may be a problem with either our beliefs or the current theory. At the same time directly finding a model from the existing data would make generalizing results difficult. A considerable difficultly in this process is how to specify the model in the first...
Show moreModeling a biological systems, is a cyclic process which involves constructing a model from current theory and beliefs and then validating that model against the data. If the data does not match, qualitatively or quantitatively then there may be a problem with either our beliefs or the current theory. At the same time directly finding a model from the existing data would make generalizing results difficult. A considerable difficultly in this process is how to specify the model in the first place. There is a need to be practice which accounts for the growing use of mathematical and statistical methods. However, as a systems becomes more complex, standard mathematical approaches may not be sufficient. In the field of ecology, the standard techniques involve discrete maps, and continuous models such as ODE's. The intent of this work is to present the mathematics necessary to study hybrids of these two models, then consider two case studies. In first case we con sider a coral reef with continuous change, except in the presence of hurricanes. The results of the data are compared quantitatively and qualitatively with simulation results. For the second case we consider a model for rabies with a periodic birth pulse. Here the analysis is qualitative as we demonstrate the existence of a strange attractor by looking at the intersections of the stable and unstable manifold for the saddle point generating the attractor. For both cases studies the introduction of a discrete event into a continuous system is done via a Dirac Distribution or Measure.
Show less  Date Issued
 2015
 PURL
 http://purl.flvc.org/fau/fd/FA00004508, http://purl.flvc.org/fau/fd/FA00004508
 Subject Headings
 Artificial intellligence  Biological applications, Biology  Mathematical models, Computational intelligence, Differential dynamical systems, Nonliner mechanics  Mathematical models
 Format
 Document (PDF)
 Title
 Short sea shipping cost benefit analysis using mathematical modeling.
 Creator
 Galletebeitia, Alvaro., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
 Abstract/Description

With congestion, environmental Impact, and the price of oil becoming topics that influence businesses and individuals in a daily basis, measures need to be undertaken in order to accommodate the growing demand for freight transportation. By directing many of the trucks travelling along the National Highways Systems to the Marine Highway corridors developed by the U.S. Maritime Administrations, many of the problems can be addressed in the Short and Medium terms. In order to do so, Short Sea...
Show moreWith congestion, environmental Impact, and the price of oil becoming topics that influence businesses and individuals in a daily basis, measures need to be undertaken in order to accommodate the growing demand for freight transportation. By directing many of the trucks travelling along the National Highways Systems to the Marine Highway corridors developed by the U.S. Maritime Administrations, many of the problems can be addressed in the Short and Medium terms. In order to do so, Short Sea Shipping, through the use of Ro/Ro (Rollon/Rolloff) Vessels, needs to be implemented. Although the environmental and congestion reducing benefits are considerable, the profitability of this transportation mode needs to be considered. A cost benefit analysis can determine the margin of profit, and attract investors and businesses. By developing a mathematical model that accounts the costs associated with transporting trucks along a particular corridor, the competitiveness of Short Sea Shipping can be determined.
Show less  Date Issued
 2011
 PURL
 http://purl.flvc.org/FAU/3332259
 Subject Headings
 Coastwise shipping, Mathematical models, Shipment of goods, Mathematical models, Freight and freightage, Management, Shipping, Economic aspects
 Format
 Document (PDF)
 Title
 StormInduced Neashore Sediment Transport.
 Creator
 Warren, William F., Briggs, Tiffany Roberts, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Geosciences
 Abstract/Description

Each year storms impact coastal areas, sometimes causing significant morphologic change. Cold fronts are associated with increased wave energy and frequently occur during the winter months along many coasts, such as the Atlantic and Gulf of Mexico. The higher wave energy can be responsible for a large quantity of the sediment transport resulting in rapid morphologic change. Using streamer traps, the vertical distribution of onshoredirected sediment transport during two different cold fronts...
Show moreEach year storms impact coastal areas, sometimes causing significant morphologic change. Cold fronts are associated with increased wave energy and frequently occur during the winter months along many coasts, such as the Atlantic and Gulf of Mexico. The higher wave energy can be responsible for a large quantity of the sediment transport resulting in rapid morphologic change. Using streamer traps, the vertical distribution of onshoredirected sediment transport during two different cold fronts on two lowwave energy beaches (i.e., along the northern Yucatan and southeast Florida) were compared with the resulting morphologic change. The objectives of this study are to: 1) analyze the grain size distribution (statistics) of sediment transported during a cold front, 2) compare the vertical sediment distribution throughout the water column, and 3) compare characteristics of bed sediment to the sediment within the water column. Understanding the changing grain size distribution of bottom sediments in comparison to directional transport (throughout the water column) should help determine the sediment fraction(s) being eroded or deposited, which could greatly improve predictions of storminduced morphology change.
Show less  Date Issued
 2017
 PURL
 http://purl.flvc.org/fau/fd/FA00004830, http://purl.flvc.org/fau/fd/FA00004830
 Subject Headings
 Coast changesMathematical models., Coastal zone management., Geomorphology., Sediment transportAnalysis., Coastal engineeringMathematical models.
 Format
 Document (PDF)
 Title
 Modeling strategic resource allocation in probabilistic global supply chain system with genetic algorithm.
 Creator
 Damrongwongsiri, Montri., Florida Atlantic University, Han, Chingping (Jim), College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
 Abstract/Description

Effective and efficient supply chain management is essential for domestic and global organizations to compete successfully in the international market. Superior inventory control policies and product distribution strategies along with advanced information technology enable an organization to collaborate distribution and allocation of inventory to gain a competitive advantage in the world market. Our research establishes the strategic resource allocation model to capture and encapsulate the...
Show moreEffective and efficient supply chain management is essential for domestic and global organizations to compete successfully in the international market. Superior inventory control policies and product distribution strategies along with advanced information technology enable an organization to collaborate distribution and allocation of inventory to gain a competitive advantage in the world market. Our research establishes the strategic resource allocation model to capture and encapsulate the complexity of the modern global supply chain management problem. A mathematical model was constructed to depict the stochastic, multipleperiod, twoechelon inventory with the manytomany demandsupplier network problem. The model simultaneously constitutes the uncertainties of inventory control and transportation parameters as well as the varying price factors. A genetic algorithm (GA) was applied to derive optimal solutions through a twostage optimization process. Practical examples and solutions from three sourcing strategies (single sourcing, multiple sourcing, and dedicated system) were included to illustrate the GA based solution procedure. Our model can be utilized as a collaborative supply chain strategic planning tool to efficiently determine the appropriate inventory allocation and a dynamic decision making process to effectively manage the distribution plan.
Show less  Date Issued
 2003
 PURL
 http://purl.flvc.org/fcla/dt/12056
 Subject Headings
 Business logisticsMathematical models, Physical distribution of goodsManagement, Inventory controlMathematical models, Genetic algorithms
 Format
 Document (PDF)
 Title
 A structural equations model of organizational commitment, job satisfaction as its covariate, and their antecedent variables.
 Creator
 McFarland, Michael Allen, Florida Atlantic University, Mendell, Jay S.
 Abstract/Description

This academic exercise in organizational commitment research explores the causal relationships between organizational commitment, job satisfaction as its covariate latent exogenous variable and nine manifest endogenous variables: (a) organizational conflict, (b) personal values/role conflict, (c) cognitive/affective attitude, (d) intention to leave the organization, (e) job security, (f) role ambiguity, (g) job satisfaction, (h) organizational commitment and, (i) the deficiency in meeting...
Show moreThis academic exercise in organizational commitment research explores the causal relationships between organizational commitment, job satisfaction as its covariate latent exogenous variable and nine manifest endogenous variables: (a) organizational conflict, (b) personal values/role conflict, (c) cognitive/affective attitude, (d) intention to leave the organization, (e) job security, (f) role ambiguity, (g) job satisfaction, (h) organizational commitment and, (i) the deficiency in meeting basic Maslovian needs. This data sample of 400 (faculty members from four public community college districts in southcentral Florida) represented urban and nonurban community colleges, large and small campuses, east and westcoast community colleges, and both full and parttime faculty. The covariance matrix based on complete data for the sample (n = 400), along with information of the estimated reliabilities, were analyzed using EzPATH, the SYSTAT implementation of structured equations modeling. GFI criteria accompanied diagnostic output and are provided. The path coefficients of the primary model and their respective standard errors complied with accepted statistical methods in most cases. Also, the root mean square residual of the primary model was .0180. The pvalue for the primary model was 0.4506 which was supported by a chisquare (χ2) divided by DOF equating to 1.00513. The determined AGFI and GFI indices were .9755 and .9897 respectively. Only the psychological attitudes of conflict, either conflicting standards of the organization or personal values with the organization, and role ambiguity, showed any direct influence by satisfaction and nonsignificant influence by commitment. Only the psychological attitudes of cognitive/affective attitude, intention to leave the organization, and job security showed any direct influence by commitment and nonsignificant influence by satisfaction. In this study, job satisfaction and commitment show a mutual causal relationship with each other (represented by the high mutual causation coefficient of 0.94556 SE = 0.02163). The primary model was modified to address both the path of satisfaction being a precedent of commitment (SAT > COM) and commitment being a precedent of satisfaction (COM > SAT). Neither of these two models demonstrated goodness of fit criteria as strong as the primary model. This dissertation has shown that by using carefully collected data, it is possible to construct structural equation models consisting entirely of psychologicalsocial variables in a model as large as nine manifest endogenous variables.
Show less  Date Issued
 1994
 PURL
 http://purl.flvc.org/fcla/dt/12394
 Subject Headings
 Job satisfactionMathematical models, Organizational behaviorMathematical models, Organizational change, Personnel management, Employee motivation, Commitment (Psychology)
 Format
 Document (PDF)
 Title
 SHORTTERM FORECASTING METHODS WITH REFERENCE TO MONROE COUNTY.
 Creator
 PEREZ, JOSE RAMON., Florida Atlantic University, Stronge, William B., College of Business, Department of Economics
 Abstract/Description

This thesis is a study of shortterm forecasting models within the reference area of Monroe County. Its main concern being the nature of the models, and the accuracy of predictions rather than the actual forecast. The results are of interest to the student of forecasting and of Monroe County. A proxy model is introduced as an alternative to other methods of regional analysis with the intention of inducing further research on the field.
 Date Issued
 1972
 PURL
 http://purl.flvc.org/fcla/dt/13515
 Subject Headings
 Economic forecastingMathematical models, Economic forecastingFloridaMonroe County, Monroe County (Fla)Economic conditionsMathematical models
 Format
 Document (PDF)