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Title: ROLLBACK-ABLE RANDOM NUMBER GENERATORS FOR THE SYNCHRONOUS PARALLEL ENVIRONMENT FOR EMULATION AND DISCRETE-EVENT SIMULATION (SPEEDES).
Creator: Narayanan, Ramaswamy Karthik, Rabelo, Luis, University of Central Florida
Abstract / Description: Random Numbers form the heart and soul of a discrete-event simulation system. There are few situations where the actions of the entities in the process being simulated can be completely predicted in advance. The real world processes are more probabilistic than deterministic. Hence, such chances are represented in the system by using various statistical models, like random number generators. These random number generators can be used to represent a various number of factors, such as length of...
Show moreRandom Numbers form the heart and soul of a discrete-event simulation system. There are few situations where the actions of the entities in the process being simulated can be completely predicted in advance. The real world processes are more probabilistic than deterministic. Hence, such chances are represented in the system by using various statistical models, like random number generators. These random number generators can be used to represent a various number of factors, such as length of the queue. However, simulations have grown in size and are sometimes required to run on multiple machines, which share the various methods or events in the simulation among themselves. These Machines can be distributed across a LAN or even the internet. In such cases, to keep the validity of the simulation model, we need rollback-able random number generators. This thesis is an effort to develop such rollback able random number generators for the Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES) environment developed by NASA. These rollback-able random number generators will also add several statistical distribution models to the already rich SPEEDES library.
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Date Issued: 2005
Identifier: CFE0000328, ucf:46292
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000328

Title: DEVELOPING AN OBJECT-ORIENTED APPROACH FOR OPERATIONS SIMULATION IN SPEEDES.
Creator: Wasadikar, Amit, Rabelo, Luis, University of Central Florida
Abstract / Description: Using simulation techniques, performance of any proposed system can be tested for different scenarios with a generated model. However, it is difficult to rapidly create simulation models that will accurately represent the complexity of the system. In recent years, Object-Oriented Discrete-Event Simulation has emerged as the potential technology to implement rapid simulation schemes. A number of software based on programming languages like C++ and Java are available for carrying out Object...
Show moreUsing simulation techniques, performance of any proposed system can be tested for different scenarios with a generated model. However, it is difficult to rapidly create simulation models that will accurately represent the complexity of the system. In recent years, Object-Oriented Discrete-Event Simulation has emerged as the potential technology to implement rapid simulation schemes. A number of software based on programming languages like C++ and Java are available for carrying out Object Oriented Discrete-Event Simulation. These software packages establish a general framework for simulation in computer programs, but need to be further customized for desired end-use applications. In this thesis, a generic simulation library is created for the distributed Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES). This library offers classes to model the functionality of servers, processes, resources, transporters, and decisions. The library is expected to produce efficient simulation models in less time and with a lesser amount of coding. The class hierarchy is modeled using the Unified Modeling Language (UML). To test the library, the existing SPEEDES Space Shuttle Model is enhanced and recreated. This enhanced model is successfully validated against the original Arena model.
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Date Issued: 2005
Identifier: CFE0000332, ucf:46278
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000332

Title: SPEEDES: A CASE STUDY OF SPACE OPERATIONS.
Creator: Paruchuri, Amith, Rabelo, Luis, University of Central Florida
Abstract / Description: This thesis describes the application of parallel simulation techniques to represent the structured functional parallelism present within the Space Shuttle Operations Flow using the Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES), an object-oriented multi-computing architecture. SPEEDES is a unified parallel simulation environment, which allocates events over multiple processors to get simulation speed up. Its optimistic processing capability minimizes...
Show moreThis thesis describes the application of parallel simulation techniques to represent the structured functional parallelism present within the Space Shuttle Operations Flow using the Synchronous Parallel Environment for Emulation and Discrete-Event Simulation (SPEEDES), an object-oriented multi-computing architecture. SPEEDES is a unified parallel simulation environment, which allocates events over multiple processors to get simulation speed up. Its optimistic processing capability minimizes simulation lag time behind wall clock time, or multiples of real-time. SPEEDES accommodates an increase in process complexity with additional parallel computing nodes to allow sharing of processing loads. This thesis focuses on the process of translating a model of Space Shuttle Operations from a procedural oriented and single processor approach to one represented in a process-driven, object-oriented, and distributed processor approach. The processes are depicted by several classes created to represent the operations at the space center. The reference model used is the existing Space Shuttle Model created in ARENA by NASA and UCF in the year 2001. A systematic approach was used for this translation. A reduced version of the ARENA model was created, and then used as the SPEEDES prototype using C++. The prototype was systematically augmented to reflect the entire Space Shuttle Operations Flow. It was then verified, validated, and implemented.
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Date Issued: 2005
Identifier: CFE0000330, ucf:46286
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000330

Title: EVOLUTIONARY OPTIMIZATION OF SUPPORT VECTOR MACHINES.
Creator: Gruber, Fred, Rabelo, Luis, University of Central Florida
Abstract / Description: Support vector machines are a relatively new approach for creating classifiers that have become increasingly popular in the machine learning community. They present several advantages over other methods like neural networks in areas like training speed, convergence, complexity control of the classifier, as well as a stronger mathematical background based on optimization and statistical learning theory. This thesis deals with the problem of model selection with support vector machines, that is...
Show moreSupport vector machines are a relatively new approach for creating classifiers that have become increasingly popular in the machine learning community. They present several advantages over other methods like neural networks in areas like training speed, convergence, complexity control of the classifier, as well as a stronger mathematical background based on optimization and statistical learning theory. This thesis deals with the problem of model selection with support vector machines, that is, the problem of finding the optimal parameters that will improve the performance of the algorithm. It is shown that genetic algorithms provide an effective way to find the optimal parameters for support vector machines. The proposed algorithm is compared with a backpropagation Neural Network in a dataset that represents individual models for electronic commerce.
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Date Issued: 2004
Identifier: CFE0000244, ucf:46251
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000244

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: VALUE MAPPING FRAMEWORK INVOLVING STAKEHOLDERS FOR SUPPLY CHAIN IMPROVEMENT WHEN IMPLEMENTING INFORMATION TECHNOLOGY PROJECTS.
Creator: Moore, Karla, Rabelo, Luis, University of Central Florida
Abstract / Description: Successful Supply Chain Management (SCM) depends on how well an organization performs internal and external communications with trading partners, executes the logistics component, and understands/monitors related costs of conducting its business. The use of information technology (IT) is considered a prerequisite for the effective control of today's complex supply chains. Increased communication technology has redefined how businesses work together, raised customer expectations, and...
Show moreSuccessful Supply Chain Management (SCM) depends on how well an organization performs internal and external communications with trading partners, executes the logistics component, and understands/monitors related costs of conducting its business. The use of information technology (IT) is considered a prerequisite for the effective control of today's complex supply chains. Increased communication technology has redefined how businesses work together, raised customer expectations, and placed new demands on supply chain performance. IT components with proven and rapid return-on-investment are favored to support critical supply chain processes such as leaner manufacturing processes, consumer-driven supply chains, and customer responsiveness. The use of IT in the digital era has become critical and it is treated as a major competitive tool for success. Complex and comprehensive IT infrastructures support the firm's communications network, databases, and operating systems. Information technology facilitates the creation of value. However, the creation of value is defined by the different groups of stakeholders. Therefore, stakeholders must be integrated into this process of change management that uses IT as the enabler. Supply chains are due to change when higher levels of performance and/or adaptation are required as mandated by changes in the business structure and/or benchmarking and/or regulations. One of the major problems for any supply chain executive is to understand and manage these changes. These changes usually require the implementation of an IT project. Therefore, the successful design, execution, and completion of these IT projects are important for the supply chain. SCM is now a strategic function addressed at the highest levels of the organization in concert with multiple stakeholders on both the supplier and customer side of the table. The aim of this dissertation is to develop a value mapping framework involving stakeholders to improve supply chain performance when implementing IT projects. The framework has components that help define the supply chain, measure the size of the issues, identify necessary changes in the metrics to improve performance, measure the organizational consequences of these changes, and develop and follow a plan to implement IT projects to achieve the new goals of performance. Through this new framework, these IT projects will be able to bring the supply chain from a current state "As is" to a future state "To be"; capturing the existing and desired states of the proposed changes which are aligned with the objectives and goals of the organization. Therefore, the IT project can be designed, executed, and completed. One unique component of this framework is the inclusion of the stakeholders at different stages. This framework identifies the group of stakeholders to be taken into consideration in order to define the future "To be" state. In addition, the framework identifies the value creation of the "To be" system as seen by the stakeholders.
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Date Issued: 2008
Identifier: CFE0002108, ucf:47541
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002108

Title: A FRAMEWORK FOR THE ASSESSMENT AND ANALYSIS OF MULTI-HAZARDSINDUCED RISK RESULTING FROM SPACE VEHICLES OPERATIONS.
Creator: Sala-Diakanda, Serge, Rabelo, Luis, University of Central Florida
Abstract / Description: With the foreseeable increase in traffic frequency to and from orbit, the safe operation of current and future space vehicles at designated spaceports has become a serious concern. Due to their high explosive energy potential, operating those launch vehicles presents a real risk to: (1) the spaceport infrastructure and personnel, (2) the communities surrounding the spaceport and (3) the flying aircrafts whose routes could be relatively close to spaceport launch and reentry routes. Several...
Show moreWith the foreseeable increase in traffic frequency to and from orbit, the safe operation of current and future space vehicles at designated spaceports has become a serious concern. Due to their high explosive energy potential, operating those launch vehicles presents a real risk to: (1) the spaceport infrastructure and personnel, (2) the communities surrounding the spaceport and (3) the flying aircrafts whose routes could be relatively close to spaceport launch and reentry routes. Several computer models aimed at modeling the effects of the different hazards generated by the breakup of such vehicles (e.g., fragmentation of debris, release of toxic gases, propagation of blast waves, etc.) have been developed, and are used to assist in Go-No Go launch decisions. They can simulate a total failure scenario of the vehicle and, estimate a number of casualties to be expected as a result of such failure. However, as all of these models – which can be very elaborate and complex – consider only one specific explosion hazard in their simulations, the decision of whether or not a launch should occur is currently based on the evaluation of several estimates of an expected number of casualties. As such, current practices ignore the complex, nonlinear interactions between the different hazards as well as the interdependencies between the estimates. In this study, we developed a new framework which makes use of information fusion theory, hazards' dispersion modeling and, geographical statistical analysis and visualization capabilities of geographical information systems to assess the risk generated by the operation of space launch vehicles. A new risk metric, which effectively addresses the lack of a common risk metric with current methods, is also proposed. A case study, based on a proposed spaceport in the state of Oklahoma showed that the estimates we generate through our framework consistently outperform estimates provided by any individual hazard, or by the independent combination of those hazards. Furthermore, the study revealed that using anything else than fusion could provide seriously misleading results, with potentially catastrophic consequences.
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Date Issued: 2007
Identifier: CFE0001606, ucf:47178
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001606

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: ASSESSMENT FRAMEWORK FOR THE EVALUATION AND PRIORITIZATION OF UNIVERSITY TECHNOLOGIES FOR LICENSING AND COMMERCIALIZATION.
Creator: Rahal, Ahmad, Rabelo, Luis, University of Central Florida
Abstract / Description: US corporations have long recognized university related scientific research as an important source of long term economic growth and technological innovation. This dynamic involvement with industry has drastically increased the university technology transfer and licensing activities, and has stretched the human and financial resources of Technology Management and Licensing Offices of many US universities. This research provides a mechanism that can aid in the complex process of properly...
Show moreUS corporations have long recognized university related scientific research as an important source of long term economic growth and technological innovation. This dynamic involvement with industry has drastically increased the university technology transfer and licensing activities, and has stretched the human and financial resources of Technology Management and Licensing Offices of many US universities. This research provides a mechanism that can aid in the complex process of properly assessing university-owned technologies and intellectual properties, to identify those with licensing and commercialization potential for the pursuit of truly important breakthrough discoveries. This research focuses on the university technology licensing and commercialization process from the perspectives of those licensing professionals whose firms' activities are engaged in licensing-in university technologies. The objectives of this research are to: 1.Identify the decision factors and licensing determinants that influence or impact the licensing and commercialization of university technologies. 2.Build and conduct a survey among those licensing professionals involved in the technology licensing process to determine the relative importance of each of the licensing determinants identified in the literature review, and their most current and up to date selection criteria for technologies they license. 3.Develop a framework to assist the University Technology Management & Transfer Office's personnel and other stakeholders in the assessment of the potential viability of the university technologies for licensing and commercialization.
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Date Issued: 2005
Identifier: CFE0000659, ucf:46505
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000659

Title: USING THE SOFTWARE ADAPTER TO CONNECT LEGACY SIMULATION MODELS TO THE RTI.
Creator: Rachapalli, Deepak Kumar, Rabelo, Luis, University of Central Florida
Abstract / Description: The establishment of a network of persistent shared simulations depends on the presence of a robust standard for communicating state information between those simulations. The High Level Architecture (HLA) can serve as the basis for such a standard. While the HLA is architecture, not software, use of Run Time Infrastructure (RTI) software is required to support operations of a federation execution. The integration of RTI with existing simulation models is complex and requires a lot of...
Show moreThe establishment of a network of persistent shared simulations depends on the presence of a robust standard for communicating state information between those simulations. The High Level Architecture (HLA) can serve as the basis for such a standard. While the HLA is architecture, not software, use of Run Time Infrastructure (RTI) software is required to support operations of a federation execution. The integration of RTI with existing simulation models is complex and requires a lot of expertise. This thesis implements a less complex and effective interaction between a legacy simulation model and RTI using a middleware tool known as Distributed Manufacturing Simulation (DMS) adapter. Shuttle Model, an Arena based discrete-event simulation model for shuttle operations, is connected to the RTI using the DMS adapter. The adapter provides a set of functions that are to be incorporated within the Shuttle Model, in a procedural manner, in order to connect to RTI. This thesis presents the procedure when the Shuttle Model connects to the RTI, to communicate with the Scrub Model for approval of its shuttle's launch.
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Date Issued: 2006
Identifier: CFE0000922, ucf:46764
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000922

Title: A HOLISTIC USABILITY FRAMEWORK FOR DISTRIBUTED SIMULATION SYSTEMS.
Creator: Dawson, Jeffrey, Rabelo, Luis, University of Central Florida
Abstract / Description: This dissertation develops a holistic usability framework for distributed simulation systems (DSSs). The framework is developed considering relevant research in human-computer interaction, computer science, technical writing, engineering, management, and psychology. The methodology used consists of three steps: (1) framework development, (2) surveys of users to validate and refine the framework, and to determine attribute weights, and (3) application of the framework to two real-world systems...
Show moreThis dissertation develops a holistic usability framework for distributed simulation systems (DSSs). The framework is developed considering relevant research in human-computer interaction, computer science, technical writing, engineering, management, and psychology. The methodology used consists of three steps: (1) framework development, (2) surveys of users to validate and refine the framework, and to determine attribute weights, and (3) application of the framework to two real-world systems. The concept of a holistic usability framework for DSSs arose during a project to improve the usability of the Virtual Test Bed, a prototypical DSS, and the framework is partly a result of that project. In addition, DSSs at Ames Research Center were studied for additional insights. The framework has six dimensions: end user needs, end user interface(s), programming, installation, training, and documentation. The categories of participants in this study include managers, researchers, programmers, end users, trainers, and trainees. The first survey was used to obtain qualitative and quantitative data to validate and refine the framework. Attributes that failed the validation test were dropped from the framework. A second survey was used to obtain attribute weights. The refined framework was used to evaluate two existing DSSs, measuring their holistic usabilities. Ensuring that the needs of the variety of types of users who interact with the system during design, development, and use are met is important to launch a successful system. Adequate consideration of system usability along the several dimensions in the framework will not only ensure system success but also increase productivity, lower life cycle costs, and result in a more pleasurable working experience for people who work with the system.
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Date Issued: 2006
Identifier: CFE0001256, ucf:46906
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001256

Title: A REAL OPTION STRATEGIC SCORECARD DECISION FRAMEWORK FOR IT PROJECT SELECTION.
Creator: Munoz, Cesar, Rabelo, Luis, University of Central Florida
Abstract / Description: ABSTRACT The problem of project selection is of significant importance in management of information systems. Almost $2 trillion is spent worldwide every year on IT projects, with over $600 billion spent in the US alone. Traditionally, managers have being using the classical net present value (NPV) method in conjunction with multicriteria scoring models for ROI analysis and selection of IT project investments The multicriteria models use ad-hoc evaluation criteria to assign priority weights...
Show moreABSTRACT The problem of project selection is of significant importance in management of information systems. Almost $2 trillion is spent worldwide every year on IT projects, with over $600 billion spent in the US alone. Traditionally, managers have being using the classical net present value (NPV) method in conjunction with multicriteria scoring models for ROI analysis and selection of IT project investments The multicriteria models use ad-hoc evaluation criteria to assign priority weights and then rate the alternatives against each criterion. These models have two limitations. First, the criteria and weights are based on subjective judgments, allowing the introduction of politics in the information management decision process and the generation of arbitrary results. Second, the classical approach uses deterministic estimations of the cost, benefits and the returns of the projects, without considering the impact of uncertainty and risk in the business decisions. This research proposed a better alternative for ROI analysis and selection of IT projects using a real option strategic scorecard (ROSS) approach. In contrast with traditional methodologies and previous research work, the ROSS decision framework uses a more comprehensive, axiomatic approach for systematically measuring both the business value and the strategic implications of IT project investments. The ROSS approach integrates in a unified IT project management decision framework the best elements of real option theory, strategic balanced scorecards, Monte Carlo simulations and analytical network processes to fully analyzes the effect of uncertainty and risk in the IT investment decisions. In addition, the ROSS approach complies with the critical success factors that have being identified in the literature for validation of IT decision frameworks. The main benefit of the ROSS approach is to enable managers to better compare and rank projects in the IT portfolio, optimizing the ROI analysis and selection of information system projects.
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Date Issued: 2006
Identifier: CFE0001331, ucf:46975
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001331

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: 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: Data Mining Models for Tackling High Dimensional Datasets and Outliers.
Creator: Panagopoulos, Orestis, Xanthopoulos, Petros, Rabelo, Luis, Zheng, Qipeng, Dechev, Damian, University of Central Florida
Abstract / Description: High dimensional data and the presence of outliers in data each pose a serious challenge in supervised learning.Datasets with significantly larger number of features compared to samples arise in various areas, including business analytics and biomedical applications. Such datasets pose a serious challenge to standard statistical methods and render many existing classification techniques impractical. The generalization ability of many classification algorithms is compromised due to the so...
Show moreHigh dimensional data and the presence of outliers in data each pose a serious challenge in supervised learning.Datasets with significantly larger number of features compared to samples arise in various areas, including business analytics and biomedical applications. Such datasets pose a serious challenge to standard statistical methods and render many existing classification techniques impractical. The generalization ability of many classification algorithms is compromised due to the so-called curse of dimensionality. A new binary classification method called constrained subspace classifier (CSC) is proposed for such high dimensional datasets. CSC improves on an earlier proposed classification method called local subspace classifier (LSC) by accounting for the relative angle between subspaces while approximating the classes with individual subspaces. CSC is formulated as an optimization problem and can be solved by an efficient alternating optimization technique. Classification performance is tested in publicly available datasets. The improvement in classification accuracy over LSC shows the importance of considering the relative angle between the subspaces while approximating the classes. Additionally, CSC appears to be a robust classifier, compared to traditional two step methods that perform feature selection and classification in two distinct steps.Outliers can be present in real world datasets due to noise or measurement errors. The presence of outliers can affect the training phase of machine learning algorithms, leading to over-fitting which results in poor generalization ability. A new regression method called relaxed support vector regression (RSVR) is proposed for such datasets. RSVR is based on the concept of constraint relaxation which leads to increased robustness in datasets with outliers. RSVR is formulated using both linear and quadratic loss functions. Numerical experiments on benchmark datasets and computational comparisons with other popular regression methods depict the behavior of our proposed method. RSVR achieves better overall performance than support vector regression (SVR) in measures such as RMSE and $R^2_{adj}$ while being on par with other state-of-the-art regression methods such as robust regression (RR). Additionally, RSVR provides robustness for higher dimensional datasets which is a limitation of RR, the robust equivalent of ordinary least squares regression. Moreover, RSVR can be used on datasets that contain varying levels of noise.Lastly, we present a new novelty detection model called relaxed one-class support vector machines (ROSVMs) that deals with the problem of one-class classification in the presence of outliers.
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Date Issued: 2016
Identifier: CFE0006698, ucf:51920
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006698

Title: A framework for prioritizing opportunities of improvement in the context of business excellence model in healthcare organization.
Creator: Aldarmaki, Alia, Elshennawy, Ahmad, Lee, Gene, Rabelo, Luis, Darwish, Mohammed, University of Central Florida
Abstract / Description: In today's world, the healthcare sector is facing challenges to improve the efficiency and effectiveness of its operations. More and more improvement projects are being adopted to enhance healthcare services, making it more patient-centric, and enabling better cost control. Healthcare organizations strive to identify and carry out such improvement initiatives to sustain their businesses and gain competitive advantage. Seeking to reach a higher operational level of excellence, healthcare...
Show moreIn today's world, the healthcare sector is facing challenges to improve the efficiency and effectiveness of its operations. More and more improvement projects are being adopted to enhance healthcare services, making it more patient-centric, and enabling better cost control. Healthcare organizations strive to identify and carry out such improvement initiatives to sustain their businesses and gain competitive advantage. Seeking to reach a higher operational level of excellence, healthcare organizations utilize business excellence criteria to conduct assessment and identify organizational strengths and weaknesses. However, while such assessments routinely identify numerous areas for potential improvement, it is not feasible to conduct all improvement projects simultaneously due to limitations in time, capital, and personnel, as well as conflict with other organization's projects or strategic objectives. An effective prioritization and selection approach is valuable in that it can assist the organization to optimize its available resources and outcomes. This study attempts to enable such an approach by developing a framework to prioritize improvement opportunities in healthcare in the context of the business excellence model through the integration of the Fuzzy Delphi Method and Fuzzy Interface System. To carry out the evaluation process, the framework consists of two phases. The first phase utilizes Fuzzy Delphi Method to identify the most significant factors that should be considered in healthcare for electing the improvement projects. The FDM is employed to handle the subjectivity of human assessment. The research identifies potential factors for evaluating projects, then utilizes FDM to capture expertise knowledge. The first round in FDM is intended to validate the identified list of factors from experts; which includes collecting additional factors from experts that the literature might have overlooked. When an acceptable level of consensus has been reached, a second round is conducted to obtain experts' and other related stakeholders' opinions on the appropriate weight of each factor's importance. Finally, FDM analyses eliminate or retain the criteria to produce a final list of critical factors to select improvement projects. The second phase in the framework attempts to prioritize improvement initiatives using the Hierarchical Fuzzy Interface System. The Fuzzy Interface System combines the experts' ratings for each improvement opportunity with respect to the factors deemed critical to compute the priority index. In the process of calculating the priority index, the framework allows the estimation of other intermediate indices including: social, financial impact, strategical, operational feasibility, and managerial indices. These indices bring an insight into the improvement opportunities with respect to each framework's dimensions. The framework allows for a reduction of the bias in the assessment by developing a knowledge based on the perspectives of multiple experts.
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Date Issued: 2018
Identifier: CFE0007304, ucf:52158
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007304

Title: Factors Affecting Systems Engineering Rigor in Launch Vehicle Organizations.
Creator: Gibson, Denton, Karwowski, Waldemar, Rabelo, Luis, Kotnour, Timothy, Kern, David, University of Central Florida
Abstract / Description: Systems engineering is a methodical multi-disciplinary approach to design, build, and operate complex systems. Launch vehicles are considered by many extremely complex systems that have greatly impacted where the systems engineering industry is today. Launch vehicles are used to transport payloads from the ground to a location in space. Satellites launched by launch vehicles can range from commercial communications to national security payloads. Satellite costs can range from a few million...
Show moreSystems engineering is a methodical multi-disciplinary approach to design, build, and operate complex systems. Launch vehicles are considered by many extremely complex systems that have greatly impacted where the systems engineering industry is today. Launch vehicles are used to transport payloads from the ground to a location in space. Satellites launched by launch vehicles can range from commercial communications to national security payloads. Satellite costs can range from a few million dollars to billions of dollars. Prior research suggests that lack of systems engineering rigor as one of the leading contributors to launch vehicle failures. A launch vehicle failure could have economic, societal, scientific, and national security impacts. This is why it is critical to understand the factors that affect systems engineering rigor in U.S. launch vehicle organizations.The current research examined organizational factors that influence systems engineering rigor in launch vehicle organizations. This study examined the effects of the factors of systems engineering culture and systems engineering support on systems engineering rigor. Particularly, the effects of top management support, organizational commitment, systems engineering support, and value of systems engineering were examined. This research study also analyzed the mediating role of systems engineering support between top management support and systems engineering rigor, as well as between organizational commitment and systems engineering rigor. A quantitative approach was used for this. Data for the study was collected via survey instrument. A total of 203 people in various systems engineering roles in launch vehicle organizations throughout the United States voluntarily participated. Each latent construct of the study was validated using confirmatory factor analysis (CFA). Structural equation modeling (SEM) was used to examine the relationships between the variables of the study. The IBM SPSS Amos 25 software was used to analyze the CFA and SEM.
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Date Issued: 2019
Identifier: CFE0007806, ucf:52348
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007806

Title: The Challenges and Barriers Facing Successful Lean Implementation in the Qatari Manufacturing Organizations.
Creator: Alyousef, Abdulwahab, Elshennawy, Ahmad, Rabelo, Luis, Lee, Gene, University of Central Florida
Abstract / Description: The success of Toyota, the inventor of Lean Systems has drawn the attention of academics, researchers, and executives in the last decades. However, existing lean research is largely focused on developed economies in Europe, the Americas, and in Southeast Asia with little focus on the Arab world in general and Qatar specifically. There has been an emergence of manufacturing organizations and Small and Medium- sized Enterprises (SME) in Qatar recently which was the focus of this research....
Show moreThe success of Toyota, the inventor of Lean Systems has drawn the attention of academics, researchers, and executives in the last decades. However, existing lean research is largely focused on developed economies in Europe, the Americas, and in Southeast Asia with little focus on the Arab world in general and Qatar specifically. There has been an emergence of manufacturing organizations and Small and Medium- sized Enterprises (SME) in Qatar recently which was the focus of this research. Despite the many attempts to implement lean in organizations, there have been a large number of failed attempts. This research aims to study the Qatari Manufacturing Organizations attempts in implementing lean. The main goal of the thesis is to shed a light on the current state of awareness of lean in Qatari Manufacturing Industry and SME and the potential barriers and challenges that prevent the successful adoption of lean. In order to do so, an online survey was designed through the SurveyMonkey tool and organizations were asked to participate.Numerical and statistical results from the survey are discussed along with Pareto charts and two hypothesis tests. The finding indicates that there is no difference between ISO certified and Non-ISO certified organizations in lean implementation. Further, it is understood that most of the manufacturing organizations in Qatar have some level of awareness of lean concepts/tools and practices. The results also show that organizations are not implementing lean concepts and are not using quality management practices effectively. The main obstacle that manufacturing organizations in Qatar face when implementing lean is (")Lack of Employee Engagement(") and (")Unsupportive Organization Culture("). However, it is noted that the research has some limitations such as having most participating organizations in the survey from specific sectors.
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Date Issued: 2019
Identifier: CFE0007778, ucf:52368
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007778

Title: Methods for online feature selection for classification problems.
Creator: Razmjoo, Alaleh, Zheng, Qipeng, Rabelo, Luis, Boginski, Vladimir, Xanthopoulos, Petros, University of Central Florida
Abstract / Description: Online learning is a growing branch of machine learning which allows all traditional data miningtechniques to be applied on an online stream of data in real-time. In this dissertation, we presentthree efficient algorithms for feature ranking in online classification problems. Each of the methodsare tailored to work well with different types of classification tasks and have different advantages.The reason for this variety of algorithms is that like other machine learning solutions, there is...
Show moreOnline learning is a growing branch of machine learning which allows all traditional data miningtechniques to be applied on an online stream of data in real-time. In this dissertation, we presentthree efficient algorithms for feature ranking in online classification problems. Each of the methodsare tailored to work well with different types of classification tasks and have different advantages.The reason for this variety of algorithms is that like other machine learning solutions, there is usuallyno algorithm which works well for all types of tasks. The first method, is an online sensitivitybased feature ranking (SFR) which is updated incrementally, and is designed for classificationtasks with continuous features. We take advantage of the concept of global sensitivity and rankfeatures based on their impact on the outcome of the classification model. In the feature selectionpart, we use a two-stage filtering method in order to first eliminate highly correlated and redundantfeatures and then eliminate irrelevant features in the second stage. One important advantage of ouralgorithm is its generality, which means the method works for correlated feature spaces withoutpreprocessing. It can be implemented along with any single-pass online classification method withseparating hyperplane such as SVMs. In the second method, with help of probability theory wepropose an algorithm which measures the importance of the features by observing the changes inlabel prediction in case of feature substitution. A non-parametric version of the proposed methodis presented to eliminate the distribution type assumptions. These methods are application to alldata types including mixed feature spaces. At last, we present a class-based feature importanceranking method which evaluates the importance of each feature for each class, these sub-rankingsare further exploited to train an ensemble of classifiers. The proposed methods will be thoroughlytested using benchmark datasets and the results will be discussed in the last chapter.
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Date Issued: 2018
Identifier: CFE0007584, ucf:52567
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007584

Title: Development of an MRM federation system using COTS simulations.
Creator: Kim, Jaeho, Lee, Gene, Elshennawy, Ahmad, Rabelo, Luis, University of Central Florida
Abstract / Description: The goal of this research is to build an experimental environment for the Simulation Interoperability Laboratory (SIL) of the University of Central Florida (UCF). The Simulation Interoperability Laboratory (SIL) is researching about multi-resolution modeling(MRM), with a focus on military field uses. This thesis proposes steps to develop an MRM federation system and build two different MRM systems using COTS simulations (SIMBox, VR-Forces, and MASA Sword). This report is written to provide...
Show moreThe goal of this research is to build an experimental environment for the Simulation Interoperability Laboratory (SIL) of the University of Central Florida (UCF). The Simulation Interoperability Laboratory (SIL) is researching about multi-resolution modeling(MRM), with a focus on military field uses. This thesis proposes steps to develop an MRM federation system and build two different MRM systems using COTS simulations (SIMBox, VR-Forces, and MASA Sword). This report is written to provide the basis for a time-based MRM federation study in the Simulation Interoperability Laboratory. The report describes many definitions and notions related to Multi-Resolution Modeling(MRM) and discusses examples to make better understanding for further research. MRM is relatively new research, and there are high demands for integrating simulators running in military field purposes. Most military-related research is based on simulators currently being used in the military; this poses a problem for research because the data is classified, resulting in many limitations for outside researchers to see the military's process for building an MRM system or the results of the research. Therefore, development of the MRM federation using COTS simulations can provide many examples of MRM issues for future research.Keywords: Multi-Resolution Modeling, MRM, aggregation, disaggregation, MRE, MRM approach.
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Date Issued: 2018
Identifier: CFE0007576, ucf:52565
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007576

System Dynamics (8)	+ -
Machine Learning (4)	+ -
Simulation (4)	+ -
DFSS (3)	+ -
HLA (3)	+ -

Healthcare (3)	+ -
Industrial Engineering (3)	+ -
SPEEDES (3)	+ -
Agent Based Simulation (2)	+ -
Balanced Scorecard (2)	+ -
Change Management (2)	+ -
Customer Satisfaction (2)	+ -
Data Mining (2)	+ -
Engineering Management (2)	+ -
Hybrid Simulation (2)	+ -
Internet of Things (2)	+ -
LVC simulation (2)	+ -
Leadership (2)	+ -
Live (2)	+ -
Performance Excellence (2)	+ -
RTI (2)	+ -
Real Options Analysis (2)	+ -
Stakeholders (2)	+ -
Supply Chain Management (2)	+ -
Virtual (2)	+ -
Virtual Reality (2)	+ -
genetic algorithms (2)	+ -
interoperability (2)	+ -
lean (2)	+ -
manufacturing (2)	+ -

University of Central Florida (68)	+ -
Rabelo, Luis (67)	+ -
Elshennawy, Ahmad (35)	+ -
Lee, Gene (29)	+ -
Xanthopoulos, Petros (11)	+ -

Karwowski, Waldemar (8)	+ -
Rahal, Ahmad (7)	+ -
Kincaid, John (6)	+ -
Zheng, Qipeng (6)	+ -
Ajayi, Richard (5)	+ -
Ahmad, Ali (4)	+ -
McCauley, Pamela (4)	+ -
Pazour, Jennifer (4)	+ -
Darwish, Mohammed (2)	+ -
Ferreras, Ana (2)	+ -
Mollaghasemi, Mansooreh (2)	+ -
O'Neal, Thomas (2)	+ -
Porter, Robert (2)	+ -
Sarmiento, Alfonso (2)	+ -
Thompson, William (2)	+ -
Williams, Kent (2)	+ -
Abboodi, Mohammed (1)	+ -
Al-Foraih, Saleh (1)	+ -
Al-Shamkhani, Maher T. (1)	+ -
Albar, Abdulrahman (1)	+ -
Aldarmaki, Alia (1)	+ -
Alexander, Tiffaney (1)	+ -
Alghamdi, Mohammed (1)	+ -
Ali, Abdulelah (1)	+ -
Almalki, Hamed (1)	+ -

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