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Title: ASCERTAINING THE GROWTH OF A COMPANYA SYSTEM DYNAMICS APPRAOCH.
Creator: Noor Mohideen, Fakir Mohideen, Rabelo, Luis, University of Central Florida
Abstract / Description: Business is often about creating change for other businesses. At times, these changes affect only the company and at other times they affect the entire industry. There is a time in the life of a business when its fundamental way of functioning is questioned and is subjected to change. That change can mean an opportunity to rise to new heights, or it might even signal the beginning of the end. This fundamental change in any business is known as an inflection point. Understanding the nature of...
Show moreBusiness is often about creating change for other businesses. At times, these changes affect only the company and at other times they affect the entire industry. There is a time in the life of a business when its fundamental way of functioning is questioned and is subjected to change. That change can mean an opportunity to rise to new heights, or it might even signal the beginning of the end. This fundamental change in any business is known as an inflection point. Understanding the nature of its inflection point and responding to that point suitably will help to safeguard a company's growth. So today's managers, when faced with such changes, have to be equipped with the adequate tools to guide the company out of troubles and to place it in a position where it can prosper. The fundamental changes can be scrutinized by studying the internal dynamic behavior of the system. Therefore, the managers are required to be systems thinkers so that they can study the internal dynamic behavior of the company and maneuver the inflection point successfully. System dynamics is an effective tool, which helps the managers to understand the structure and internal dynamic behaviors of a large and complex system. System dynamics models are developed to assist the management to navigate its way through the inflection point. This thesis focuses on how system dynamics model-analysis and model based policy development process can help a company to overcome an inflection point. Further enhancements and calibrations can be done to the model to provide industry specific solutions.
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Date Issued: 2005
Identifier: CFE0000335, ucf:46300
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000335

Title: A METHODOLOGY FOR MINIMIZING THE OSCILLATIONS IN SUPPLY CHAINS USING SYSTEM DYNAMICS AND GENETIC ALGORITHMS.
Creator: LAKKOJU, RAMAMOORTHY, RABELO, LUIS, University of Central Florida
Abstract / Description: Supply Chain Management (SCM) is a critically significant strategy that enterprises depend on to meet challenges that they face because of highly competitive and dynamic business environments of today. Supply chain management involves the entire network of processes from procurement of raw materials/services/technologies to manufacturing or servicing intermediate products/services to converting them into final products or services and then distributing and retailing them till they reach final...
Show moreSupply Chain Management (SCM) is a critically significant strategy that enterprises depend on to meet challenges that they face because of highly competitive and dynamic business environments of today. Supply chain management involves the entire network of processes from procurement of raw materials/services/technologies to manufacturing or servicing intermediate products/services to converting them into final products or services and then distributing and retailing them till they reach final customers. A supply chain network by nature is a large and complex, engineering and management system. Oscillations occurring in a supply chain because of internal and/or external influences and measures to be taken to mitigate/minimize those oscillations are a core concern in managing the supply chain and driving an organization towards a competitive advantage. The objective of this thesis is to develop a methodology to minimize the oscillations occurring in a supply chain by making use of the techniques of System Dynamics (SD) and Genetic Algorithms (GAs). System dynamics is a very efficient tool to model large and complex systems in order to understand their complex, non-linear dynamic behavior. GAs are stochastic search algorithms, based on the mechanics of natural selection and natural genetics, used to search complex and non-linear search spaces where traditional techniques may be unsuitable.
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Date Issued: 2005
Identifier: CFE0000683, ucf:46489
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000683

Title: Dynamic Modeling Approach to Quantify Change Orders Impact on Labor Productivity.
Creator: Al-Kofahi, Zain, Oloufa, Amr, Tatari, Omer, Uddin, Nizam, Xanthopoulos, Petros, University of Central Florida
Abstract / Description: In construction projects, change orders are commonly faced. These change orders, which are issued by the owner, may cause interruption to the contractor's work, resulting in damages such as loss of labor productivity, delay damages, and cost overruns which may lead to claims. The relationship between change orders and loss of labor productivity is not well understood because of the difficulty in linking the cause of the productivity loss to the change order. So, to receive compensation, the...
Show moreIn construction projects, change orders are commonly faced. These change orders, which are issued by the owner, may cause interruption to the contractor's work, resulting in damages such as loss of labor productivity, delay damages, and cost overruns which may lead to claims. The relationship between change orders and loss of labor productivity is not well understood because of the difficulty in linking the cause of the productivity loss to the change order. So, to receive compensation, the contractor needs to prove with a credible calculation that the productivity loss was a result of the change order issued by the owner. Compared to all available productivity loss quantification methods, the (")Measured Mile(") approach is considered the most acceptable and popular approach in litigation. In this study, loss of labor productivity due to change orders is studied using a system dynamics method. A system dynamics model is developed using Vensim Software, validated, and utilized to quantitatively measure the impact of the change in the project scope on labor productivity. Different road construction projects were analyzed using both methods: measured mile analysis and system dynamics model; then, the results from those two approaches were compared
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Date Issued: 2016
Identifier: CFE0006430, ucf:51448
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006430

Title: A Framework For Workforce Management An Agent Based Simulation Approach.
Creator: Marin, Mario, Rabelo, Luis, Lee, Gene, Elshennawy, Ahmad, Kincaid, John, University of Central Florida
Abstract / Description: In today's advanced technology world, enterprises are in a constant state of competition. As the intensity of competition increases the need to continuously improve organizational performance has never been greater. Managers at all levels must be on a constant quest for finding ways to maximize their enterprises' strategic resources. Enterprises can develop sustained competitiveness only if their activities create value in unique ways. There should be an emphasis to transfer this...
Show moreIn today's advanced technology world, enterprises are in a constant state of competition. As the intensity of competition increases the need to continuously improve organizational performance has never been greater. Managers at all levels must be on a constant quest for finding ways to maximize their enterprises' strategic resources. Enterprises can develop sustained competitiveness only if their activities create value in unique ways. There should be an emphasis to transfer this competitiveness to the resources it has on hand and the resources it can develop to be used in this environment. The significance of human capital is even greater now, as the intangible value and the tacit knowledge of enterprises' resources should be strategically managed to achieve a greater level of continuous organizational success. This research effort seeks to provide managers with means for accurate decision making for their workforce management. A framework for modeling and managing human capital to achieve effective workforce planning strategies is built to assist enterprise in their long term strategic organizational goals.
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Date Issued: 2014
Identifier: CFE0005375, ucf:50439
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005375

Title: A HYBRID SYSTEM DYNAMICS-DISCRETE EVENT SIMULATIONAPPROACH TO SIMULATING THE MANUFACTURING ENTERPRISE.
Creator: Helal, Magdy, Rabelo, Luis, University of Central Florida
Abstract / Description: With the advances in the information and computing technologies, the ways the manufacturing enterprise systems are being managed are changing. More integration and adoption of the system perspective push further towards a more flattened enterprise. This, in addition to the varying levels of aggregation and details and the presence of the continuous and discrete types of behavior, created serious challenges for the use of the existing simulation tools for simulating the modern manufacturing...
Show moreWith the advances in the information and computing technologies, the ways the manufacturing enterprise systems are being managed are changing. More integration and adoption of the system perspective push further towards a more flattened enterprise. This, in addition to the varying levels of aggregation and details and the presence of the continuous and discrete types of behavior, created serious challenges for the use of the existing simulation tools for simulating the modern manufacturing enterprise system. The commonly used discrete event simulation (DES) techniques face difficulties in modeling such integrated systems due to increased model complexity, the lack of data at the aggregate management levels, and the unsuitability of DES to model the financial sectors of the enterprise. System dynamics (SD) has been effective in providing the needs of top management levels but unsuccessful in offering the needed granularity at the detailed operational levels of the manufacturing system. On the other hand the existing hybrid continuous-discrete tools are based on certain assumptions that do not fit the requirements of the common decision making situations in the business systems. This research has identified a need for new simulation modeling approaches that responds to the changing business environments towards more integration and flattened enterprise systems. These tools should be able to develop comprehensive models that are inexpensive, scalable, and able to accommodate the continuous and discrete modes of behavior, the stochastic and deterministic natures of the various business units, and the detail complexity and dynamic complexity perspectives in decision making. The research proposes and develops a framework to combine and synchronize the SD and DES simulation paradigms to simulate the manufacturing enterprise system. The new approach can respond to the identified requirements in simulating the modern manufacturing enterprise systems. It is directed toward building comprehensive simulation models that can accommodate all management levels while explicitly recognizing the differences between them in terms of scope and frequency of decision making as well as the levels of details preferred and used at each level. This SDDES framework maintains the integrity of the two simulation paradigms and can use existing/legacy simulation models without requiring learning new simulation or computer programming skills. The new framework uses a modular structure by which the SD and DES models are treated as members of a comprehensive simulation. A new synchronization mechanism that that maintains the integrity of the two simulation paradigms and is not event-driven is utilized to coordinate the interactions between the simulation modules. It avoids having one simulation paradigm dominating the other. For communication and model management purposes the SDDES formalism provides a generic format to describe, specify, and document the simulation modules and the information sharing processes. The SDDES controller which is the communication manager, implements the synchronization mechanism and manages the simulation run ensuring correct exchange of data in terms of timeliness and format, between the modules. It also offers the user interface through which users interact with the simulation modules.
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Date Issued: 2008
Identifier: CFE0002264, ucf:47835
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002264

Title: Modeling the innovation ecosystem and development of a dynamic innovation index.
Creator: Schoen, Henriette, Karwowski, Waldemar, Hoekstra, Robert, Shumaker, Randall, Akbas, Mustafa, University of Central Florida
Abstract / Description: The topic of innovation currently generates a tremendous amount of interest around the world. Innovation is considered an essential part of the solution to creating more jobs and improving the socio-economic conditions of many countries around the globe. Innovation comes about through the existence of many interrelated solutions to socio-economic problems in an extensively interconnected network, which create value for each other. Such a complex creativity and innovation value-creating...
Show moreThe topic of innovation currently generates a tremendous amount of interest around the world. Innovation is considered an essential part of the solution to creating more jobs and improving the socio-economic conditions of many countries around the globe. Innovation comes about through the existence of many interrelated solutions to socio-economic problems in an extensively interconnected network, which create value for each other. Such a complex creativity and innovation value-creating network is here called an Innovation Ecosystem (IE). The main objective of this dissertation research is to improve the current understanding of the IE by developing a simulation model that uses a broad set of relevant static and dynamic variables and incorporates the principles of system dynamics (SD). The proposed model, which is named the IECO-model is based on the relationships between 91 variables and the combined influences of the 43 parameters. Available data for 32 countries, representing a full span of GDP worldwide, was used to study the level of innovation in each of these countries. The result of the developed IECO-model is a novel ranking of the level of innovation through a dynamic innovation index, called the DII. The DII is a new tool to evaluate the innovation and entrepreneurship level of a given country in the context of the global economy. The most significant differentiator from other existing indices of innovation is that the DII is focusing more on the entrepreneurship qualities in 19 of the 43 parameters by looking at cultural values and belief systems, the social context, existing entrepreneurial culture, innovation attitudes, and mentality of each of the considered countries. According to DII-based ranking, the ten most innovative countries in the world are 1. Switzerland, 2. USA, 3. Finland, 4. Netherlands, 5. Iceland, 6. Sweden, 7. Germany, 8. Denmark, 9. The United Kingdom, and 10. Austria.
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Date Issued: 2018
Identifier: CFE0007586, ucf:52537
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007586

Title: A HYBRID SIMULATION METHODOLOGY TO EVALUATE NETWORK CENTRICDECISION MAKING UNDER EXTREME EVENTS.
Creator: Quijada, Sergio, Sepulveda, Jose, University of Central Florida
Abstract / Description: Currently the network centric operation and network centric warfare have generated a new area of research focused on determining how hierarchical organizations composed by human beings and machines make decisions over collaborative environments. One of the most stressful scenarios for these kinds of organizations is the so-called extreme events. This dissertation provides a hybrid simulation methodology based on classical simulation paradigms combined with social network analysis for...
Show moreCurrently the network centric operation and network centric warfare have generated a new area of research focused on determining how hierarchical organizations composed by human beings and machines make decisions over collaborative environments. One of the most stressful scenarios for these kinds of organizations is the so-called extreme events. This dissertation provides a hybrid simulation methodology based on classical simulation paradigms combined with social network analysis for evaluating and improving the organizational structures and procedures, mainly the incident command systems and plans for facing those extreme events. According to this, we provide a methodology for generating hypotheses and afterwards testing organizational procedures either in real training systems or simulation models with validated data. As long as the organization changes their dyadic relationships dynamically over time, we propose to capture the longitudinal digraph in time and analyze it by means of its adjacency matrix. Thus, by using an object oriented approach, three domains are proposed for better understanding the performance and the surrounding environment of an emergency management organization. System dynamics is used for modeling the critical infrastructure linked to the warning alerts of a given organization at federal, state and local levels. Discrete simulations based on the defined concept of "community of state" enables us to control the complete model. Discrete event simulation allows us to create entities that represent the data and resource flows within the organization. We propose that cognitive models might well be suited in our methodology. For instance, we show how the team performance decays in time, according to the Yerkes-Dodson curve, affecting the measures of performance of the whole organizational system. Accordingly we suggest that the hybrid model could be applied to other types of organizations, such as military peacekeeping operations and joint task forces. Along with providing insight about organizations, the methodology supports the analysis of the "after action review" (AAR), based on collection of data obtained from the command and control systems or the so-called training scenarios. Furthermore, a rich set of mathematical measures arises from the hybrid models such as triad census, dyad census, eigenvalues, utilization, feedback loops, etc., which provides a strong foundation for studying an emergency management organization. Future research will be necessary for analyzing real data and validating the proposed methodology.
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Date Issued: 2006
Identifier: CFE0001243, ucf:46926
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001243

Title: SOLITARY WAVE FAMILIES IN TWO NON-INTEGRABLE MODELS USING REVERSIBLE SYSTEMS THEORY.
Creator: Leto, Jonathan, Choudhury, S. Roy, University of Central Florida
Abstract / Description: In this thesis, we apply a recently developed technique to comprehensively categorize all possible families of solitary wave solutions in two models of topical interest. The models considered are: a) the Generalized Pochhammer-Chree Equations, which govern the propagation of longitudinal waves in elastic rods, and b) a generalized microstructure PDE. Limited analytic results exist for the occurrence of one family of solitary wave solutions for each of these equations. Since, as mentioned...
Show moreIn this thesis, we apply a recently developed technique to comprehensively categorize all possible families of solitary wave solutions in two models of topical interest. The models considered are: a) the Generalized Pochhammer-Chree Equations, which govern the propagation of longitudinal waves in elastic rods, and b) a generalized microstructure PDE. Limited analytic results exist for the occurrence of one family of solitary wave solutions for each of these equations. Since, as mentioned above, solitary wave solutions often play a central role in the long-time evolution of an initial disturbance, we consider such solutions of both models here (via the normal form approach) within the framework of reversible systems theory. Besides confirming the existence of the known family of solitary waves for each model, we find a continuum of delocalized solitary waves (or homoclinics to small-amplitude periodic orbits). On isolated curves in the relevant parameter region, the delocalized waves reduce to genuine embedded solitons. For the microstructure equation, the new family of solutions occur in regions of parameter space distinct from the known solitary wave solutions and are thus entirely new. Directions for future work, including the dynamics of each family of solitary waves using exponential asymptotics techniques, are also mentioned.
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Date Issued: 2008
Identifier: CFE0002151, ucf:47930
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002151

Title: A System Dynamics Approach on Sustainability Assessment of the United States Urban Commuter Transportation.
Creator: Ercan, Tolga, Tatari, Omer, Oloufa, Amr, Eluru, Naveen, Xanthopoulos, Petros, University of Central Florida
Abstract / Description: Transportation sector is one of the largest emission sources and is a cause for human health concern due to the high dependency on personal vehicle in the U.S. Transportation mode choice studies are currently limited to micro- and regional-level boundaries, lacking of presenting a complete picture of the issues, and the root causes associated with urban passenger transportation choices in the U.S. Hence, system dynamics modeling approach is utilized to capture complex causal relationships...
Show moreTransportation sector is one of the largest emission sources and is a cause for human health concern due to the high dependency on personal vehicle in the U.S. Transportation mode choice studies are currently limited to micro- and regional-level boundaries, lacking of presenting a complete picture of the issues, and the root causes associated with urban passenger transportation choices in the U.S. Hence, system dynamics modeling approach is utilized to capture complex causal relationships among the critical system parameters affecting alternative transportation mode choices in the U.S. as well as to identify possible policy areas to improve alternative transportation mode choice rates for future years up to 2050. Considering the high degree of uncertainties inherent to the problem, multivariate sensitivity analysis is utilized to explore the effectiveness of existing and possible policy implications in dynamic model in the terms of their potential to increase transit ridership and locating critical parameters that influences the most on mode choice and emission rates. Finally, the dissertation advances the current body of knowledge by integrating discrete event simulation (multinomial fractional split model) and system dynamics for hybrid urban commuter transportation simulation to test new scenarios such as autonomous vehicle (AV) adoption along with traditional policy scenarios such as limiting lane-mile increase on roadways and introducing carbon tax policy on vehicle owners. Overall, the developed simulation models clearly indicate the importance of urban structures to secure the future of alternative transportation modes in the U.S. as the prevailing policy practices fail to change system behavior. Thus, transportation system needs a paradigm shift to radically change current impacts and the market penetration of AVs can be one of the reforms to provoke this transition since it is expected to revolutionize mode choice, emission trends, and the built environment.
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Date Issued: 2019
Identifier: CFE0007626, ucf:52554
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007626

Title: ALGEBRAIC ASPECTS OF (BIO) NANO-CHEMICAL REACTION NETWORKS AND BIFURCATIONS IN VARIOUS DYNAMICAL SYSTEMS.
Creator: Chen, Teng, Brennan, Joseph, University of Central Florida
Abstract / Description: The dynamics of (bio) chemical reaction networks have been studied by different methods. Among these methods, the chemical reaction network theory has been proven to successfully predicate important qualitative properties, such as the existence of the steady state and the asymptotic behavior of the steady state. However, a constructive approach to the steady state locus has not been presented. In this thesis, with the help of toric geometry, we propose a generic strategy towards this question...
Show moreThe dynamics of (bio) chemical reaction networks have been studied by different methods. Among these methods, the chemical reaction network theory has been proven to successfully predicate important qualitative properties, such as the existence of the steady state and the asymptotic behavior of the steady state. However, a constructive approach to the steady state locus has not been presented. In this thesis, with the help of toric geometry, we propose a generic strategy towards this question. This theory is applied to (bio)nano particle con gurations. We also investigate Hopf bifurcation surfaces of various dynamical systems.
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Date Issued: 2011
Identifier: CFE0003933, ucf:48689
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003933

Title: Strategic Improvement: A Systems Approach using the Balanced Scorecard Methodology to Increase Federally Financed Research at the University of Central Florida.
Creator: Walters, Joseph, Rabelo, Luis, Ajayi, Richard, Calabrese, Mark, University of Central Florida
Abstract / Description: The University of Central Florida has many successful measures to reflect on as it celebrates its 50th year in 2013. It is the university with the 2nd largest student population in the U. S. and its overall ranking in the U.S. News (&) World Report has improved 4 years in a row. However, with respect to research, the federally funded research and development for the University of Central Florida (UCF) has remained flat. In addition, when compared to other schools, its portion of those federal...
Show moreThe University of Central Florida has many successful measures to reflect on as it celebrates its 50th year in 2013. It is the university with the 2nd largest student population in the U. S. and its overall ranking in the U.S. News (&) World Report has improved 4 years in a row. However, with respect to research, the federally funded research and development for the University of Central Florida (UCF) has remained flat. In addition, when compared to other schools, its portion of those federal research dollars is small. This thesis lays the groundwork for developing a model for improving the federally financed academic research and development. A systems approach using the balanced scorecard methodology was used to develop causal loop relationships between the many factors that influence the federal funding process. Measures are proposed that link back to the objectives and mission of the university. One particular measure found in the literature was refined to improve its integration into this model. The resulting work provides a framework with specific measures that can be incorporated at the university to improve their share of the federally financed research and development. Although developed for UCF this work could be applied to any university that desires to improve their standing in the federal financed academic research and development market.
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Date Issued: 2013
Identifier: CFE0005069, ucf:49955
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005069

Title: Computational Fluid Dynamics Uncertainty Analysis for Payload Fairing Spacecraft Environmental Control Systems.
Creator: Groves, Curtis, Kassab, Alain, Das, Tuhin, Kauffman, Jeffrey, Moore, Brian, University of Central Florida
Abstract / Description: Spacecraft thermal protection systems are at risk of being damaged due to airflow produced from Environmental Control Systems. There are inherent uncertainties and errors associated with using Computational Fluid Dynamics to predict the airflow field around a spacecraft from the Environmental Control System. This paper describes an approach to quantify the uncertainty in using Computational Fluid Dynamics to predict airflow speeds around an encapsulated spacecraft without the use of test data...
Show moreSpacecraft thermal protection systems are at risk of being damaged due to airflow produced from Environmental Control Systems. There are inherent uncertainties and errors associated with using Computational Fluid Dynamics to predict the airflow field around a spacecraft from the Environmental Control System. This paper describes an approach to quantify the uncertainty in using Computational Fluid Dynamics to predict airflow speeds around an encapsulated spacecraft without the use of test data. Quantifying the uncertainty in analytical predictions is imperative to the success of any simulation-based product. The method could provide an alternative to traditional (")validation by test only(") mentality. This method could be extended to other disciplines and has potential to provide uncertainty for any numerical simulation, thus lowering the cost of performing these verifications while increasing the confidence in those predictions.Spacecraft requirements can include a maximum airflow speed to protect delicate instruments during ground processing. Computational Fluid Dynamics can be used to verify these requirements; however, the model must be validated by test data. This research includes the following three objectives and methods. Objective one is develop, model, and perform a Computational Fluid Dynamics analysis of three (3) generic, non-proprietary, environmental control systems and spacecraft configurations. Several commercially available and open source solvers have the capability to model the turbulent, highly three-dimensional, incompressible flow regime. The proposed method uses FLUENT, STARCCM+, and OPENFOAM. Objective two is to perform an uncertainty analysis of the Computational Fluid Dynamics model using the methodology found in (")Comprehensive Approach to Verification and Validation of Computational Fluid Dynamics Simulations("). This method requires three separate grids and solutions, which quantify the error bars around Computational Fluid Dynamics predictions. The method accounts for all uncertainty terms from both numerical and input variables. Objective three is to compile a table of uncertainty parameters that could be used to estimate the error in a Computational Fluid Dynamics model of the Environmental Control System /spacecraft system.Previous studies have looked at the uncertainty in a Computational Fluid Dynamics model for a single output variable at a single point, for example the re-attachment length of a backward facing step. For the flow regime being analyzed (turbulent, three-dimensional, incompressible), the error at a single point can propagate into the solution both via flow physics and numerical methods. Calculating the uncertainty in using Computational Fluid Dynamics to accurately predict airflow speeds around encapsulated spacecraft in is imperative to the success of future missions.
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Date Issued: 2014
Identifier: CFE0005174, ucf:50662
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005174

Title: A Holistic Framework for Transitional Management.
Creator: Elattar, Ahmed, Rabelo, Luis, Pazour, Jennifer, Mollaghasemi, Mansooreh, Ajayi, Richard, University of Central Florida
Abstract / Description: For all business organizations, there comes a time when a change must take place within their eco-system. It consumes a great deal of thought and planning to ensure that the right decision is made as it could alter the entire course of their business for a number of years to come. This change may appear in the form of a brilliant CEO reaching the age of retirement, or an unsuccessful Managing Director being asked to leave before fulfilling the term of her contract. Regardless of the cause, a...
Show moreFor all business organizations, there comes a time when a change must take place within their eco-system. It consumes a great deal of thought and planning to ensure that the right decision is made as it could alter the entire course of their business for a number of years to come. This change may appear in the form of a brilliant CEO reaching the age of retirement, or an unsuccessful Managing Director being asked to leave before fulfilling the term of her contract. Regardless of the cause, a transition must occur in which a suitable successor is chosen and put into place while minimizing costs, satisfying stakeholders, ensuring that the successor has been adequately prepared for their new position, and minimizing work place gossip, among other things. It is also important to understand how the nature of the business, as well as its financial standing, effects such a transition.Engineering and management principles come together in this study to ensure that organizations going through such a change are on the right course. As the problem of transitional management is not one of concrete values and contains many ambiguous concepts, one way to tackle the problem is by utilizing various industrial engineering methodologies that allow these companies to systematically begin preparing for such a change. By default, organizational strategy has to change, technology is continually being renewed and it becomes very hard for the same leader to constantly implement new and innovative developments.Organizations today have a very poor understanding of where they currently stand and as a result the cause for a company's lack of profitability is often overlooked with time and money being wasted in an attempt to fix something that is not broken. To be able to look at the bigger picture of an organization and from there begin to close in on the main problems causing a negative impact, the Matrix of Change is used and takes in many factors to layout an accurate representation of the direction in which an organization should be headed and how it can continue to grow and remain successful. The Theory of Constraints on the other hand is used here as a step-by-step guide allowing companies to be better organized during times of change. And System Dynamics modeling is where these companies can begin to simulate and solve the dilemma of transitional management using causal loop diagrams and stock and flow diagrams.Through such tools a framework can begin to be developed, one that is valued by corporations and continually reviewed. Several case studies, simulation modeling, and a panel of experts were used in order to demonstrate and validate this framework.
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Date Issued: 2014
Identifier: CFE0005160, ucf:50708
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005160

Title: A METHODOLOGY TO STABILIZE THE SUPPLY CHAIN.
Creator: Sarmiento, Alfonso, Rabelo, Luis, University of Central Florida
Abstract / Description: In todayÃ‚Â's world, supply chains are facing market dynamics dominated by strong global competition, high labor costs, shorter product life cycles, and environmental regulations. Supply chains have evolved to keep pace with the rapid growth in these business dynamics, becoming longer and more complex. As a result, supply chains are systems with a great number of network connections among their multiple components. The interactions of the network components with respect...
Show moreIn todayÃ‚Â's world, supply chains are facing market dynamics dominated by strong global competition, high labor costs, shorter product life cycles, and environmental regulations. Supply chains have evolved to keep pace with the rapid growth in these business dynamics, becoming longer and more complex. As a result, supply chains are systems with a great number of network connections among their multiple components. The interactions of the network components with respect to each other and the environment cause these systems to behave in a highly nonlinear dynamic manner. Ripple effects that have a huge, negative impact on the behavior of the supply chain (SC) are called instabilities. They can produce oscillations in demand forecasts, inventory levels, and employment rates and, cause unpredictability in revenues and profits. Instabilities amplify risk, raise the cost of capital, and lower profits. To reduce these negative impacts, modern enterprise managers must be able to change policies and plans quickly when those consequences can be detrimental. This research proposes the development of a methodology that, based on the concepts of asymptotic stability and accumulated deviations from equilibrium (ADE) convergence, can be used to stabilize a great variety of supply chains at the aggregate levels of decision making that correspond to strategic and tactical decision levels. The general applicability and simplicity of this method make it an effective tool for practitioners specializing in the stability analysis of systems with complex dynamics, especially those with oscillatory behavior. This methodology captures the dynamics of the supply chain by using system dynamics (SD) modeling. SD was the chosen technique because it can capture the complex relationships, feedback processes, and multiple time delays that are typical of systems in which oscillations are present. If the behavior of the supply chain shows instability patterns, such as ripple effects, the methodology solves an optimization problem to find a stabilization policy to remove instability or minimize its impact. The policy optimization problem relies upon a theorem which states that ADE convergence of a particular state variable of the system, such as inventory, implies asymptotic stability for that variable. The stabilization based on the ADE requires neither linearization of the system nor direct knowledge of the internal structure of the model. Moreover, the ADE concept can be incorporated easily in any SD modeling language. The optimization algorithm combines the advantage of particle swarm optimization (PSO) to determine good regions of the search space with the advantage of local optimization to quickly find the optimal point within those regions. The local search uses a Powell hill-climbing (PHC) algorithm as an improved procedure to the solution obtained from the PSO algorithm, which assures a fast convergence of the ADE. The experiments showed that solutions generated by this hybrid optimization algorithm were robust. A framework built on the premises of this methodology can contribute to the analysis of planning strategies to design robust supply chains. These improved supply chains can then effectively cope with significant changes and disturbances, providing companies with the corresponding cost savings.
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Date Issued: 2010
Identifier: CFE0002986, ucf:47977
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002986

Title: Development of an Adaptive Restoration Tool For a Self-Healing Smart Grid.
Creator: Golshani, Amir, Sun, Wei, Qu, Zhihua, Vosoughi, Azadeh, Zhou, Qun, Zheng, Qipeng, University of Central Florida
Abstract / Description: Large power outages become more commonplace due to the increase in both frequency and strength of natural disasters and cyber-attacks. The outages and blackouts cost American industries and business billions of dollars and jeopardize the lives of hospital patients. The losses can be greatlyreduced with a fast, reliable and flexible restoration tool. Fast recovery and successfully adapting to extreme events are critical to build a resilient, and ultimately self-healing power grid. This...
Show moreLarge power outages become more commonplace due to the increase in both frequency and strength of natural disasters and cyber-attacks. The outages and blackouts cost American industries and business billions of dollars and jeopardize the lives of hospital patients. The losses can be greatlyreduced with a fast, reliable and flexible restoration tool. Fast recovery and successfully adapting to extreme events are critical to build a resilient, and ultimately self-healing power grid. This dissertation is aimed to tackle the challenging task of developing an adaptive restoration decisionsupport system (RDSS). The RDSS determines restoration actions both in planning and real-time phases and adapts to constantly changing system conditions. First, an efficient network partitioning approach is developed to provide initial conditions for RDSS by dividing large outage network into smaller islands. Then, the comprehensive formulation of RDSS integrates different recovery phases into one optimization problem, and encompasses practical constraints including AC powerflow, dynamic reserve, and dynamic behaviors of generators and load. Also, a frequency constrained load recovery module is proposed and integrated into the RDSS to determine the optimal location and amount of load pickup. Next, the proposed RDSS is applied to harness renewable energy sources and pumped-storage hydro (PSH) units by addressing the inherent variabilities and uncertainties of renewable and coordinating wind and PSH generators. A two-stage stochastic and robust optimization problem is formulated, and solved by the integer L-shaped and column-and-constraintsgeneration decomposition algorithms. The developed RDSS tool has been tested onthe modified IEEE 39-bus and IEEE 57-bus systems under different scenarios. Numerical results demonstrate the effectiveness and efficiency of the proposed RDSS. In case of contingencies or unexpected outages during the restoration process, RDSS can quickly update the restoration plan and adapt to changing system conditions. RDSS is an important step toward a self-healing power grid and its implementation will reduce the recovery time while maintaining system security.
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Date Issued: 2017
Identifier: CFE0007284, ucf:52169
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007284

Title: MOBILITY AND SAFETY EVALUATION OF INTEGRATED DYNAMIC MERGE AND SPEED CONTROL STRATEGIES IN WORK ZONES.
Creator: Zaidi, Syed, Radwan, Essam, University of Central Florida
Abstract / Description: There has been a considerable increase in the amount of construction work on the U.S. national highways. Due to the capacity drop, which is the result of lane closure in work zone area, congestion occurs with a high traffic demand. The congestion increases number and severity of traffic conflicts which raise the potential for accidents; furthermore traffic operational properties of roadway in work zone area become worse. Intelligent Transportation System technologies have been developed and...
Show moreThere has been a considerable increase in the amount of construction work on the U.S. national highways. Due to the capacity drop, which is the result of lane closure in work zone area, congestion occurs with a high traffic demand. The congestion increases number and severity of traffic conflicts which raise the potential for accidents; furthermore traffic operational properties of roadway in work zone area become worse. Intelligent Transportation System technologies have been developed and are being deployed to improve the safety and mobility of traffic in and around work zones. The use of Dynamic Merge Controls (dynamic early merge and dynamic late merge) have been initiated to enhance traffic safety and to smooth traffic operations in work zone areas. The use of variable speed limit (VSL) systems at work zones is also one of those measures. VSL systems improve safety by helping the driver in determining the maximum speed that drivers should travel. Besides adding improvement to safety, they are also expected to improve mobility at the work zones. The main goal of this study was to evaluate the safety and operational effectiveness of the dynamic merge systems in the presence of VSL controls. VISSIM model is utilized to simulate a two-to-one lane configuration when one out of the two lanes in the work zone is closed for traffic. Two scenarios each for early and late simplified dynamic lane merge system (SDLMS) with and without VSLs, whereas one scenario each for the current Motorist Awareness System (MAS) and VSL alone were adopted to assess the effectiveness of these scenarios under different traffic demand volumes and different driversÃƒÂƒÃ‚Â‚ÃƒÂ‚Ã‚Â' compliance rates to the messages displayed by the systems. Mean throughputs and travel time were operational measures of effectiveness whereas speed variance and deceleration means were taken as safety surrogate measures. Three different logics were coded each for VSL alone, early SDLMS+VSL and late SDLMS+VSL in calibrated and validated VISSIM model for SDLMS through Vehicle Actuated Programming (VAP) code. It is found that for low and medium volume levels (V0500, V1000 and V1500), there is no significant difference between the Maintenance of Traffic (MOT) plans for mean throughputs. For higher volume levels (V2000 and V2500), late SDLMS with and without VSL produced significantly higher mean throughputs for all compliance rates and truck percentages. This study revealed that VSL increases travel time through the work zone. It is also found out that VSL makes the system safer at higher volumes (2,000 vph and 2,500 vph). Another outcome of this study is that the addition of VSL to the dynamic merge systems helps in improving the overall safety of the system by lowering speed variances and deceleration means of the vehicles travelling through the work zone. The passage of traffic through the work zone is made safer when a speed control is integrated to a dynamic merge system.
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Date Issued: 2010
Identifier: CFE0003519, ucf:48974
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003519

Title: A Framework for Measuring the Value-Added of Knowledge Processes with Analysis of Process Interactions and Dynamics.
Creator: Cintron, Jose, Rabelo, Luis, Elshennawy, Ahmad, Thompson, William, Ajayi, Richard, University of Central Florida
Abstract / Description: The most known and widely used methods use cash flows and tangible assets to measure the impact of investments in the organization's outputs. But in the last decade many newer organizations whose outputs are heavily dependent on information technology utilize knowledge as their main asset. These organizations' market values lie on the knowledge of its employees and their technological capabilities. In the current technology-based business landscape the value added by assets utilized for...
Show moreThe most known and widely used methods use cash flows and tangible assets to measure the impact of investments in the organization's outputs. But in the last decade many newer organizations whose outputs are heavily dependent on information technology utilize knowledge as their main asset. These organizations' market values lie on the knowledge of its employees and their technological capabilities. In the current technology-based business landscape the value added by assets utilized for generation of outputs cannot be appropriately measured and managed without considering the role that intangible assets and knowledge play in executing processes. The analysis of processes for comparison and decision making based on intangible value added can be accomplished using the knowledge required to execute processes. The measurement of value added by knowledge can provide a more realistic framework for analysis of processes where traditional cost methods are not appropriate, enabling managers to better allocate and control knowledge-based processes. Further consideration of interactions and complexity between proposed process alternatives can yield answers about where and when investments can improve value-added while dynamically providing higher returns on investment.
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Date Issued: 2013
Identifier: CFE0004983, ucf:49585
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004983

Title: OPTIMIZED MARKET INTRODUCTION OF LARGE CAPITAL PRODUCTS WITH LONG DEVELOPMENT AND LEARNING CYCLES.
Creator: Lembcke, Antje, Malone, Linda, University of Central Florida
Abstract / Description: Any product sold is expected to be reliable and available when the customer wants to operate it. Companies that produce large capital products (LCP), such as rockets, satellites, or large gas turbines to generate electrical energy, tend to shy away from extending their testing and validation method above the requirements by law, mainly due to the very high costs of each additional test and the uncertain return on investment. This research shows that todayÃ‚Â's state of...
Show moreAny product sold is expected to be reliable and available when the customer wants to operate it. Companies that produce large capital products (LCP), such as rockets, satellites, or large gas turbines to generate electrical energy, tend to shy away from extending their testing and validation method above the requirements by law, mainly due to the very high costs of each additional test and the uncertain return on investment. This research shows that todayÃ‚Â's state of the art validation methods for LCP, required by law, or suggested in literature, and adapted by these industries, are not capable of capturing all significant failure modes (or even enough failure modes), with the consequence that the subsequently sold commercial products will still experience failures with significant effects on product reliability, and subsequently on the companiesÃ‚Â' bottom line earnings projections. The research determines the type of data (significant variables) necessary to correlate a companyÃ‚Â's validation policy to product failures after commercialization, and predicts the financial impact of the current validation policy on the companyÃ‚Â's profitability. A systems dynamics model to assess a company's testing policy is developed and an optimized product validation plan is suggested, and its impact on a companyÃ‚Â's profitability is demonstrated through simulation. A generic methodology is derived and its viability is illustrated using a specific product and a dynamic model developed with data available to the researcher. The generic method can be applied by any company to develop its own model for optimizing product reliability prior to market introduction.
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Date Issued: 2010
Identifier: CFE0003413, ucf:48404
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003413

Title: NUTRIENT AND PATHOGEN REMOVAL IN A SUBSURFACE UPFLOW WETLAND SYSTEM USING GREEN SORPTION MEDIA.
Creator: Xuan, Zhemin, Chang, Ni-Bin, University of Central Florida
Abstract / Description: Due to environmental health and nutrient impact concerns, the conventional on-site sewage collection, treatment, and disposal systems are no longer able to meet the nutrient reduction requirements for wastewater effluent and may represent a large fraction of pollutant loads. The loads include not only nitrogen (N) and phosphorus (P), but also pathogens such as fecal coliform and E. coli which indicate the presence of other disease-causing bacteria flowing into aquatic system that adversely...
Show moreDue to environmental health and nutrient impact concerns, the conventional on-site sewage collection, treatment, and disposal systems are no longer able to meet the nutrient reduction requirements for wastewater effluent and may represent a large fraction of pollutant loads. The loads include not only nitrogen (N) and phosphorus (P), but also pathogens such as fecal coliform and E. coli which indicate the presence of other disease-causing bacteria flowing into aquatic system that adversely affect public health. A subsurface upflow wetland, which is an effective small-scale wastewater treatment system with low energy and maintenance requirements and operational costs, fits the current nutrient and pathogen removal situation having received wide attention throughout the world. Within this research study, a subsurface upflow wetland system (SUW), including four parallel SUW (three planted versus one unplanted), were constructed as a key component of the septic tank system receiving 454 liters per day (120 GPD) influent using the green sorption media along with selected plant species. It was proved effective in removing both nutrients and pathogens. During a one month test run, the planted wetlands achieved a removal efficiency of 84.2%, 97.3 %, 98.93 % and 99.92%, compared to the control wetland, 10.5%, 85.7 %, 99.74 % and 100.0 %, in total nitrogen (TN), total phosphorus (TP), fecal coli and E.Coli, respectively. Denitrification was proved to be the dominant pathway for removing N as evidenced by the mass balance and real-time PCR analyses. A simplified compartmental dynamics simulation model of constructed subsurface upflow wetlands was also developed to provide a dependable reference and tool for design of constructed subsurface upflow wetland.
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Date Issued: 2009
Identifier: CFE0002967, ucf:47964
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002967

Title: Team Interaction Dynamics during Collaborative Problem Solving.
Creator: Wiltshire, Travis, Fiore, Stephen, Jentsch, Florian, Salas, Eduardo, Wiegand, Rudolf, University of Central Florida
Abstract / Description: This dissertation contributes an enhanced understanding of team cognition, in general, and collaborative problem solving (CPS), specifically, through an integration of methods that measure team interaction dynamics and knowledge building as it occurs during a complex CPS task. The need for better understanding CPS has risen in prominence as many organizations have increasingly worked to address complex problems requiring the combination of diverse sets of individual expertise to achieve...
Show moreThis dissertation contributes an enhanced understanding of team cognition, in general, and collaborative problem solving (CPS), specifically, through an integration of methods that measure team interaction dynamics and knowledge building as it occurs during a complex CPS task. The need for better understanding CPS has risen in prominence as many organizations have increasingly worked to address complex problems requiring the combination of diverse sets of individual expertise to achieve solutions for novel problems. Towards this end, the present research drew from theoretical and empirical work on Macrocognition in Teams that describes the knowledge coordination arising from team communications during CPS. It built from this by incorporating the study of team interaction during complex collaborative cognition. Interaction between team members in such contexts has proven to be inherently dynamic and exhibiting nonlinear patterns not accounted for by extant research methods. To redress this gap, the present research drew from work in cognitive science designed to study social and team interaction as a nonlinear dynamical system. CPS was examined by studying knowledge building and interaction processes of 43 dyads working on NASA's Moonbase Alpha simulation, a CPS task. Both non-verbal and verbal interaction dynamics were examined. Specifically, frame-differencing, an automated video analysis technique, was used to capture the bodily movements of participants and content coding was applied to the teams' communications to characterize their CPS processes. A combination of linear (i.e., multiple regression, t-test, and time-lagged cross-correlation analysis), as well as nonlinear analytic techniques (i.e., recurrence quantification analysis; RQA) were applied. In terms of the predicted interaction dynamics, it was hypothesized that teams would exhibit synchronization in their bodily movements and complementarity in their communications and further, that teams more strongly exhibiting these forms of coordination will produce better problem solving outcomes. Results showed that teams did exhibit a pattern of bodily movements that could be characterized as synchronized, but higher synchronization was not systematically related to performance. Further, results showed that teams did exhibit communicative interaction that was complementary, but this was not predictive of better problem solving performance. Several exploratory research questions were proposed as a way of refining the application of these techniques to the investigation of CPS. Results showed that semantic code-based communications time-series and %REC and ENTROPY recurrence-based measures were most sensitive to differences in performance. Overall, this dissertation adds to the scientific body of knowledge by advancing theory and empirical knowledge on the forms of verbal and non-verbal team interaction during CPS, but future work remains to be conducted to identify the relationship between interaction dynamics and CPS performance.
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Date Issued: 2015
Identifier: CFE0005907, ucf:50867
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005907

System Dynamics (16)	+ -
Simulation (5)	+ -
Industrial Engineering (3)	+ -
system dynamics (3)	+ -
Agent Based Simulation (2)	+ -

Hybrid Simulation (2)	+ -
Modeling (2)	+ -
ANOVA (1)	+ -
Agaent-Based (1)	+ -
Agent Based (1)	+ -
Agent-Based (1)	+ -
Alternative Vehicle Technologies (1)	+ -
Aquatic Plants (1)	+ -
Balanced Scorecard (1)	+ -
Block hankel matrices (1)	+ -
Built-In Photovoltaics (1)	+ -
Business Models (1)	+ -
CFD (1)	+ -
COMPUTATIONAL FLUID DYNAMICS (1)	+ -
Change Management (1)	+ -
Change Orders (1)	+ -
Cinematographic Techniques (1)	+ -
Co-Flow (1)	+ -
Coanda Effects (1)	+ -
Complex Event recognition (1)	+ -
Complexity (1)	+ -
Corporate Organizations (1)	+ -
Covariance Matrices (1)	+ -
Demand forecast (1)	+ -
Diffusion Modeling (1)	+ -

University of Central Florida (38)	+ -
Rabelo, Luis (8)	+ -
Kincaid, John (7)	+ -
Karwowski, Waldemar (6)	+ -
Xanthopoulos, Petros (6)	+ -

Oloufa, Amr (5)	+ -
Tatari, Omer (5)	+ -
Ajayi, Richard (4)	+ -
Elshennawy, Ahmad (3)	+ -
Moore, Brian (3)	+ -
Shah, Mubarak (3)	+ -
Ahram, Tareq (2)	+ -
Akbas, Ilhan (2)	+ -
Al-Deek, Haitham (2)	+ -
Chang, Ni-bin (2)	+ -
Geiger, Christopher (2)	+ -
Lee, Gene (2)	+ -
Mollaghasemi, Mansooreh (2)	+ -
Pazour, Jennifer (2)	+ -
Uddin, Nizam (2)	+ -
Wiegand, Rudolf (2)	+ -
Zheng, Qipeng (2)	+ -
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Ahmed, Kareem (1)	+ -
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Basharat, Arslan (1)	+ -
Bhattacharya, Samik (1)	+ -
Bhattacharya, Subhabrata (1)	+ -

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