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Title: A COMPARISON AND EVALUATIONOFCOMMON PID TUNING METHODS.
Creator: Youney, Justin, Haralambous, Michael, University of Central Florida
Abstract / Description: The motivation behind this thesis is to consolidate and evaluate the most common Proportional Integral Derivative (PID) controller tuning techniques used in industry. These are the tuning techniques used when the plant transfer function is not known. Many of these systems are poorly tuned because such consolidated information is not easily found in one single source such as this thesis. Once one of the tuning methods are applied almost always there will be further fine tuning needed to bring...
Show moreThe motivation behind this thesis is to consolidate and evaluate the most common Proportional Integral Derivative (PID) controller tuning techniques used in industry. These are the tuning techniques used when the plant transfer function is not known. Many of these systems are poorly tuned because such consolidated information is not easily found in one single source such as this thesis. Once one of the tuning methods are applied almost always there will be further fine tuning needed to bring the system into the required design criteria. The purpose here is to find out which tuning technique will yield the lowest percent overshoot and the shortest settling time for all situations. This will give the engineer a good starting point; to minimally further adjust parameters to achieve the desired design criteria. There will also be discussion on the various algorithms used in industry. Four tuning methods will be evaluated based on their ability to control different style plants. The comparison criteria will be percent overshoot and settling time for an applied step input. The tuning methods chosen were the Ziegler-Nichols Open Loop method, the CHR method for 0% overshoot, the Ziegler-Nichols Closed Loop method, and the Rule of Thumb method. It is shown that for a second order plant with a lag and pure integration in its transfer function, the Open Loop method yielded the lowest results in terms of percent overshoot, yet the Closed Loop method had the shortest settling time. For systems of higher order than two it was shown that the CHR method gave the best performance however as the order increased the Closed Loop method gave a shorter settling time. For systems of higher order with varying lags in series the CHR method gave the best results. The Rule of thumb method usually gave similar results to that of the Closed Loop method; however for higher order systems the Rule of Thumb method gave less percent overshoot but with a longer settling time than the Closed Loop method. Since these tuning methods are used when the plant transfer function is not known, and none of the rules were found to give consistently the lowest percent overshoot, and settling time for all plants tested, there can not be a recommendation as to which method an engineer should choose to use. If the plant transfer function is known or can be reasonably modeled then the following recommendations can be followed. When tuning systems with pure integrations in their transfer function the Open Loop or Closed Loop method be used. When tuning systems of order higher than two the CHR or Closed Loop method should be used, however with high order systems with varying lags the CHR method should be used. It is the responsibility of the engineer to know how and when to implement each of the tuning rules properly.
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Date Issued: 2007
Identifier: CFE0001716, ucf:47301
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001716

Title: DESIGN OF AN ADAPTIVE AUTOPILOT FOR AN EXPENDABLE LAUNCH VEHICLE.
Creator: Plaisted, Clinton, Leonessa, Alexander, University of Central Florida
Abstract / Description: This study investigates the use of a Model Reference Adaptive Control (MRAC) direct approach to solve the attitude control problem of an Expendable Launch Vehicle (ELV) during its boost phase of flight. The adaptive autopilot design is based on Lyapunov Stability Theory and provides a useful means for controlling the ELV in the presence of environmental and dynamical uncertainties. Several different basis functions are employed to approximate the nonlinear parametric uncertainties in the...
Show moreThis study investigates the use of a Model Reference Adaptive Control (MRAC) direct approach to solve the attitude control problem of an Expendable Launch Vehicle (ELV) during its boost phase of flight. The adaptive autopilot design is based on Lyapunov Stability Theory and provides a useful means for controlling the ELV in the presence of environmental and dynamical uncertainties. Several different basis functions are employed to approximate the nonlinear parametric uncertainties in the system dynamics. The control system is designed so that the desire dresponse to a reference model would be tracked by the closed-loop system. The reference model is obtained via the feedback linearization technique applied to the nonlinear ELV dynamics. The adaptive control method is then applied to a representative ELV longitudinal motion, specifically the 6th flight of Atlas-Centaur launch vehicle (AC-6) in 1965. The simulation results presented are compared to that of the actual AC-6 post-flight trajectory reconstruction. Recommendations are made for modification and future applications of the method for several other ELV dynamics issues, such as control saturation, engine inertia, flexible body dynamics, and sloshing of liquid fuels.
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Date Issued: 2008
Identifier: CFE0002006, ucf:47616
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002006

Title: DIGITAL CONTROLLER IMPLEMENTATION FOR DISTURBANCE REJECTION IN THE OPTICAL COUPLING OF A MOBILE EXPERIMENTAL LASER TRACKING SYSTEM.
Creator: Rhodes, Matthew, Richie, Samuel, University of Central Florida
Abstract / Description: Laser tracking systems are an important aspect of the NASA space program, in particular for conducting research in relation to satellites and space port launch vehicles. Often, launches are conducted at remote sites which require all of the test equipment, including the laser tracking systems, to be portable. Portable systems are more susceptible to environmental disturbances which affect the overall tracking resolution, and consequently, the resolution of any other experimental data being...
Show moreLaser tracking systems are an important aspect of the NASA space program, in particular for conducting research in relation to satellites and space port launch vehicles. Often, launches are conducted at remote sites which require all of the test equipment, including the laser tracking systems, to be portable. Portable systems are more susceptible to environmental disturbances which affect the overall tracking resolution, and consequently, the resolution of any other experimental data being collected at any given time. This research characterizes the optical coupling between two systems in a Mobile Experimental Laser Tracking system and evaluates several control solutions to minimize disturbances within this coupling. A simulation of the optical path was developed in an extensible manner such that different control systems could be easily implemented. For an initial test, several PID controllers were utilized in parallel in order to control mirrors in the optical coupling. Despite many limiting factors of the hardware, a simple proportional control performed to expectations. Although a system implementation was never field tested, the simulation results provide the necessary insight to develop the system further. Recommendations were made for future system modifications which would allow an even higher tracking resolution.
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Date Issued: 2006
Identifier: CFE0001168, ucf:46873
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001168

Title: Decentralized Power Management in Microgrids.
Creator: Bhattacharjee, Amit, Das, Tuhin, Simaan, Marwan, Kassab, Alain, University of Central Florida
Abstract / Description: A large number of power sources, operational in a microgrid, optimum power sharing andaccordingly controlling the power sources along with scheduling loads are the biggest challenges in modern power system. In the era of smart grid, the solution is certainly not simple paralleling. Hence it is required to develop a control scheme that delivers the overall power requirements while also adhering to the power limitations of each source. As the penetration of distributed generators increase and...
Show moreA large number of power sources, operational in a microgrid, optimum power sharing andaccordingly controlling the power sources along with scheduling loads are the biggest challenges in modern power system. In the era of smart grid, the solution is certainly not simple paralleling. Hence it is required to develop a control scheme that delivers the overall power requirements while also adhering to the power limitations of each source. As the penetration of distributed generators increase and are diversified, the choice of decentralized control becomes preferable. In this work, a decentralized control framework is conceived. The primary approach is taken where a small hybrid system is investigated and decentralized control schemes were developed and subsequently tested in a hardware in the loop in conjunction with the hybrid power system setup developed at the laboratory. The control design approach is based on the energy conservation principle. However, considering the vastness ofthe real power network and its complexity of operation along with the growing demand ofsmarter grid operations, called for a revamp in the control framework design. Hence, in thelater phase of this work, a novel framework is developed based on the coupled dynamicalsystem theory, where each control node corresponds to one distributed generator connectedto the microgrid. The coupling topology and coupling strengths of individual nodes aredesigned to be adjustable. The layer is modeled as a set of coupled differential equationsof pre-assigned order. The control scheme adjusts the coupling weights so that steady stateconstraints are met at the system level, while allowing flexibility to explore the solutionspace. Additionally, the approach guarantees stable equilibria during power redistribution.The theoretical development is verified using simulations in matlab simulink environment.
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Date Issued: 2014
Identifier: CFE0005465, ucf:50386
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005465

Title: DELAY MODELING AND LONG-RANGE PREDICTIVE CONTROL OF CZOCHRALSKI GROWTH PROCESS.
Creator: Shah, Dhaval, Klemenz, Christine, University of Central Florida
Abstract / Description: This work presents the Czochralski growth dynamics as time-varying delay based model, applied to the growth of La3Ga5.5Ta0.5O14 (LGT) piezoelectric crystals. The growth of high-quality large-diameter oxides by Czochralski technique requires the theoretical understanding and optimization of all relevant process parameters, growth conditions, and melts chemistry. Presently, proportional-integral- derivative (PID) type controllers are widely accepted for constant-diameter crystal growth by...
Show moreThis work presents the Czochralski growth dynamics as time-varying delay based model, applied to the growth of La3Ga5.5Ta0.5O14 (LGT) piezoelectric crystals. The growth of high-quality large-diameter oxides by Czochralski technique requires the theoretical understanding and optimization of all relevant process parameters, growth conditions, and melts chemistry. Presently, proportional-integral- derivative (PID) type controllers are widely accepted for constant-diameter crystal growth by Czochralski. Such control systems, however, do not account for aspects such as the transportation delay of the heat from crucible wall to the crystal solidification front, heat radiated from the crucible wall above the melt surface, and varying melt level. During crystal growth, these time delays play a dominant role, and pose a significant challenge to the control design. In this study, a time varying linear delay model was applied to the identification of nonlinearities of the growth dynamics. Initial results reveled the benefits of this model with actual growth results. These results were used to develop a long-range model predictive control system design. Two different control techniques using long range prediction are studied for the comparative study. Development and testing of the new control system on real time growth system are discussed in detail. The results are promising and suggest future work in this direction. Other discussion about the problems during the crystal growth, optimization of crystal growth parameters are also studied along with the control system design.
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Date Issued: 2009
Identifier: CFE0002581, ucf:48250
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002581

Title: Lyapunov-Based Robust and Adaptive Control Design for nonlinear Uncertain Systems.
Creator: Zhang, Kun, Behal, Aman, Haralambous, Michael, Xu, Yunjun, Boloni, Ladislau, Marzocca, Piergiovanni, University of Central Florida
Abstract / Description: The control of systems with uncertain nonlinear dynamics is an important field of control scienceattracting decades of focus. In this dissertation, four different control strategies are presentedusing sliding mode control, adaptive control, dynamic compensation, and neural network for a nonlinear aeroelastic system with bounded uncertainties and external disturbance. In Chapter 2, partial state feedback adaptive control designs are proposed for two different aeroelastic systems operating in...
Show moreThe control of systems with uncertain nonlinear dynamics is an important field of control scienceattracting decades of focus. In this dissertation, four different control strategies are presentedusing sliding mode control, adaptive control, dynamic compensation, and neural network for a nonlinear aeroelastic system with bounded uncertainties and external disturbance. In Chapter 2, partial state feedback adaptive control designs are proposed for two different aeroelastic systems operating in unsteady flow. In Chapter 3, a continuous robust control design is proposed for a class of single input and single output system with uncertainties. An aeroelastic system with a trailingedge flap as its control input will be considered as the plant for demonstration of effectiveness of the controller. The controller is proved to be robust by both athematical proof and simulation results. In Chapter 3, a robust output feedback control strategy is discussed for the vibration suppression of an aeroelastic system operating in an unsteady incompressible flowfield. The aeroelastic system is actuated using a combination of leading-edge (LE) and trailing-edge (TE) flaps in the presence of different kinds of gust disturbances. In Chapter 5, a neural-network based model-free controller is designed for an aeroelastic system operating at supersonic speed. The controller is shown to be able to effectively asymptotically stabilize the system via both a Lyapunov-based stability proof and numerical simulation results.
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Date Issued: 2015
Identifier: CFE0005748, ucf:50110
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005748

Title: Stability and Control in Complex Networks of Dynamical Systems.
Creator: Manaffam, Saeed, Vosoughi, Azadeh, Behal, Aman, Atia, George, Rahnavard, Nazanin, Javidi, Tara, Das, Tuhin, University of Central Florida
Abstract / Description: Stability analysis of networked dynamical systems has been of interest in many disciplines such as biology and physics and chemistry with applications such as LASER cooling and plasma stability. These large networks are often modeled to have a completely random (Erd\"os-R\'enyi) or semi-random (Small-World) topologies. The former model is often used due to mathematical tractability while the latter has been shown to be a better model for most real life networks.The recent emergence of cyber...
Show moreStability analysis of networked dynamical systems has been of interest in many disciplines such as biology and physics and chemistry with applications such as LASER cooling and plasma stability. These large networks are often modeled to have a completely random (Erd\"os-R\'enyi) or semi-random (Small-World) topologies. The former model is often used due to mathematical tractability while the latter has been shown to be a better model for most real life networks.The recent emergence of cyber physical systems, and in particular the smart grid, has given rise to a number of engineering questions regarding the control and optimization of such networks. Some of the these questions are: \emph{How can the stability of a random network be characterized in probabilistic terms? Can the effects of network topology and system dynamics be separated? What does it take to control a large random network? Can decentralized (pinning) control be effective? If not, how large does the control network needs to be? How can decentralized or distributed controllers be designed? How the size of control network would scale with the size of networked system?}Motivated by these questions, we began by studying the probability of stability of synchronization in random networks of oscillators. We developed a stability condition separating the effects of topology and node dynamics and evaluated bounds on the probability of stability for both Erd\"os-R\'enyi (ER) and Small-World (SW) network topology models. We then turned our attention to the more realistic scenario where the dynamics of the nodes and couplings are mismatched. Utilizing the concept of $\varepsilon$-synchronization, we have studied the probability of synchronization and showed that the synchronization error, $\varepsilon$, can be arbitrarily reduced using linear controllers.We have also considered the decentralized approach of pinning control to ensure stability in such complex networks. In the pinning method, decentralized controllers are used to control a fraction of the nodes in the network. This is different from traditional decentralized approaches where all the nodes have their own controllers. While the problem of selecting the minimum number of pinning nodes is known to be NP-hard and grows exponentially with the number of nodes in the network we have devised a suboptimal algorithm to select the pinning nodes which converges linearly with network size. We have also analyzed the effectiveness of the pinning approach for the synchronization of oscillators in the networks with fast switching, where the network links disconnect and reconnect quickly relative to the node dynamics.To address the scaling problem in the design of distributed control networks, we have employed a random control network to stabilize a random plant network. Our results show that for an ER plant network, the control network needs to grow linearly with the size of the plant network.
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Date Issued: 2015
Identifier: CFE0005834, ucf:50902
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005834

Title: Synchronous Communication System for SAW Sensors Interrogation.
Creator: Troshin, Maxim, Malocha, Donald, Jones, W, Gong, Xun, University of Central Florida
Abstract / Description: During past two decades a variety of SAW based wireless sensors were invented and research is still in progress. As different frequencies, varied bandwidths, coding techniques and constantly changing post processing algorithms are being implemented, there is a constant need for a universal and adjustable synchronous communication system able to interrogate new generations of SAW sensors. This thesis presents the design of a multiple FPGA based communication system with an operational...
Show moreDuring past two decades a variety of SAW based wireless sensors were invented and research is still in progress. As different frequencies, varied bandwidths, coding techniques and constantly changing post processing algorithms are being implemented, there is a constant need for a universal and adjustable synchronous communication system able to interrogate new generations of SAW sensors. This thesis presents the design of a multiple FPGA based communication system with an operational frequency range of 450MHz-2.2GHz capable of producing user programmed modulated signal. The synchronous receiver is designed to have interchangeable chip, replacement of which would allow adjustment of the receiver's bandwidth. Within this paper the performance of the system is only evaluated at 915MHz centered 20MHz bandwidth region. An OFC temperature sensor was interrogated. Post-processing algorithms, measurement results, and proposals for the future use of the system are presented. Detailed overview of the structure and performance of every functional block along with design considerations are analyzed. Previously designed Matlab based software was adapted for post processing of the received signal. New software with simplified GUI was designed for programming of the desired signal.
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Date Issued: 2012
Identifier: CFE0004270, ucf:49543
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004270

Title: The Diffusion of Digital Dashboards: An Examination of Dashboard Utilization and the Managerial Decision Environment.
Creator: Reinking, Jeffrey, Arnold, Vicky, Roberts, Robin, Sutton, Steven, Hampton, Clark, University of Central Florida
Abstract / Description: This dissertation consists of three related studies examining the diffusion of digital dashboard technology throughout today's organizations. Dashboards, once reserved for the executive level, are now available to managers at the lower levels of the organization. For these managers, dashboards have become an integral part of their work life to support their decision environment, to provide consistency in measures, to monitor performance, and to communicate information throughout the...
Show moreThis dissertation consists of three related studies examining the diffusion of digital dashboard technology throughout today's organizations. Dashboards, once reserved for the executive level, are now available to managers at the lower levels of the organization. For these managers, dashboards have become an integral part of their work life to support their decision environment, to provide consistency in measures, to monitor performance, and to communicate information throughout the organization. Prior research in the practice literature has shown that dashboards improve managerial performance and organizational performance as well as communicate organizational goals and objectives; however, empirical research has not been conducted in this area to confirm this anecdotal evidence. Using three theories, the phenomenon surrounding the diffusion of dashboards to the lower levels of the organization are examined based on 1) dashboards as a source of interactive management control and strategy alignment, 2) the impact of dashboard quality on strategy alignment, decision environment, and performance, and 3) the impacts on dashboard utilization from the antecedents of information content and task uncertainty and the consequences of user satisfaction and managerial performance. The first study investigates why dashboards have been diffused to the lowers levels of today's organizations. The primary focus of this study is to develop an understanding about the extent of dashboard utilization by decision-makers and the antecedents and consequences of utilization that is responsible for the widespread acceptance of this technology. The data for this study is collected and analyzed through an explanatory cross-sectional field study utilizing a semi-structured questionnaire. Using data from interviews with 27 managers, a framework is developed that indicates strategy alignment and dashboards associated with interactive management control are the primary antecedents that drive dashboard diffusion. The dimensions of dashboard system quality and dashboard information quality mediate the relationship between an interactive dashboard and the extent of dashboard utilization, which leads to higher levels of managerial performance and organizational performance. This study contributes to the dashboard, strategy, and MCS literature by revealing that dashboards are not isolated technologies, rather they play an important role in the execution of strategy at the operational levels of an organization. In addition, dashboards can also function as an interactive management control, which leads to high levels of diffusion of dashboards throughout organizations. Prior strategy literature has examined strategy alignment at the higher levels and this study extends this research stream by investigating strategy alignment at the lower operational levels of the organization.The second study utilizes the IS Success Model to explore the impacts of the antecedents of dashboard system quality and dashboard information quality on the managerial decision environment in addition to the resulting consequences or 'net benefit' of managerial performance and organizational performance. A field survey is used to collect data from 391 dashboard using managers to enable the analysis of the relationships predicted in the theoretical model. The theoretical model is analyzed utilizing PLS. The results show that two dimensions of dashboard quality, system flexibility and information currency, have a positive effect the managerial decision environment. The model indicates support for the consequences of managerial performance and organizational performance resulting from higher levels of decision quality in the managerial decision environment. The model also reveals that when the dashboard measures are strategy aligned, lower levels of dashboard system flexibility are associated with improved managerial decision environment. Therefore, when organizations design their dashboard systems to support strategy alignment, managers should not be afforded high levels of system flexibility to maintain their attention on the key performance indicators selected to align with strategy. This result is a primary contribution to the strategy literature that reveals that strategy aligned dashboards are more effective in environments where the dashboard flexibility is lower. Additionally, study two also extends the strategy literature by examining strategy alignment at the lower levels of the organization, since prior research has concentrated on the higher level strategic outcomes.As dashboards become highly diffused and more managers utilize the technology, the likelihood that dashboard designers cannot provide dashboard content that fits the tasks performed by managers is higher. The third study investigates this fit between dashboard information content and task uncertainty to understand if the fit between the technology and task impacts the extent of dashboard utilization by managers based on the theory of task-technology fit (TTF). TTF predicts higher levels of utilization will increase user satisfaction and managerial performance. Data is collected from 391 managers that utilize dashboards in their weekly work life to analyze the relationships predicted in the theoretical model. PLS is utilized to analyze the theoretical model and indicates weak support of TTF impacting the extent of dashboard utilization. The model supports the hypotheses for the links between the extent of dashboard utilization and user satisfaction and managerial performance. Based on the weak findings from this theoretical model, a second model is developed and analyzed. The second model measures TTF through the mediation of task uncertainty between dashboard information content and the extent of dashboard utilization, while the first model measured TTF through interacting task uncertainty and dashboard information content. The results of the second model show strong support that TTF, as measured through mediation, increases the extent of dashboard utilization. This study contributes to the literature by empirically showing that more extensive levels of dashboard utilization are achieved through the antecedent of TTF, resulting in increased managerial satisfaction and managerial performance.
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Date Issued: 2013
Identifier: CFE0005052, ucf:49969
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005052

Title: CONTROL OF NONHOLONOMIC SYSTEMS.
Creator: Yuan, Hongliang, Qu, Zhihua, University of Central Florida
Abstract / Description: Many real-world electrical and mechanical systems have velocity-dependent constraints in their dynamic models. For example, car-like robots, unmanned aerial vehicles, autonomous underwater vehicles and hopping robots, etc. Most of these systems can be transformed into a chained form, which is considered as a canonical form of these nonholonomic systems. Hence, study of chained systems ensure their wide applicability. This thesis studied the problem of continuous feed-back control of the...
Show moreMany real-world electrical and mechanical systems have velocity-dependent constraints in their dynamic models. For example, car-like robots, unmanned aerial vehicles, autonomous underwater vehicles and hopping robots, etc. Most of these systems can be transformed into a chained form, which is considered as a canonical form of these nonholonomic systems. Hence, study of chained systems ensure their wide applicability. This thesis studied the problem of continuous feed-back control of the chained systems while pursuing inverse optimality and exponential convergence rates, as well as the feed-back stabilization problem under input saturation constraints. These studies are based on global singularity-free state transformations and controls are synthesized from resulting linear systems. Then, the application of optimal motion planning and dynamic tracking control of nonholonomic autonomous underwater vehicles is considered. The obtained trajectories satisfy the boundary conditions and the vehicles' kinematic model, hence it is smooth and feasible. A collision avoidance criteria is set up to handle the dynamic environments. The resulting controls are in closed forms and suitable for real-time implementations. Further, dynamic tracking controls are developed through the Lyapunov second method and back-stepping technique based on a NPS AUV II model. In what follows, the application of cooperative surveillance and formation control of a group of nonholonomic robots is investigated. A designing scheme is proposed to achieves a rigid formation along a circular trajectory or any arbitrary trajectories. The controllers are decentralized and are able to avoid internal and external collisions. Computer simulations are provided to verify the effectiveness of these designs.
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Date Issued: 2009
Identifier: CFE0002683, ucf:48220
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002683

Title: Optimization and design of photovoltaic micro-inverter.
Creator: Zhang, Qian, Batarseh, Issa, Shen, Zheng, Wu, Xinzhang, Lotfifard, Saeed, Kutkut, Nasser, University of Central Florida
Abstract / Description: To relieve energy shortage and environmental pollution issues, renewable energy, especially PV energy has developed rapidly in the last decade. The micro-inverter systems, with advantages in dedicated PV power harvest, flexible system size, simple installation, and enhanced safety characteristics are the future development trend of the PV power generation systems. The double-stage structure which can realize high efficiency with nice regulated sinusoidal waveforms is the mainstream for the...
Show moreTo relieve energy shortage and environmental pollution issues, renewable energy, especially PV energy has developed rapidly in the last decade. The micro-inverter systems, with advantages in dedicated PV power harvest, flexible system size, simple installation, and enhanced safety characteristics are the future development trend of the PV power generation systems. The double-stage structure which can realize high efficiency with nice regulated sinusoidal waveforms is the mainstream for the micro-inverter.This thesis studied a double stage micro-inverter system. Considering the intermittent nature of PV power, a PFC was analyzed to provide additional electrical power to the system. When the solar power is less than the load required, PFC can drag power from the utility grid.In the double stage micro-inverter, the DC/DC stage was realized by a LLC converter, which could realize soft switching automatically under frequency modulation. However it has a complicated relationship between voltage gain and load. Thus conventional variable step P(&)O MPPT techniques for PWM converter were no longer suitable for the LLC converter. To solve this problem, a novel MPPT was proposed to track MPP efficiently. Simulation and experimental results verified the effectiveness of the proposed MPPT.The DC/AC stage of the micro-inverter was realized by a BCM inverter. With duty cycle and frequency modulation, ZVS was achieved through controlling the inductor current bi-directional in every switching cycle. This technique required no additional resonant components and could be employed for low power applications on conventional full-bridge and half-bridge inverter topologies. Three different current mode control schemes were derived from the basic theory of the proposed technique. They were referred to as Boundary Current Mode (BCM), Variable Hysteresis Current Mode (VHCM), and Constant Hysteresis Current Mode (CHCM) individually in this paper with their advantages and disadvantages analyzed in detail. Simulation and experimental results demonstrated the feasibilities of the proposed soft-switching technique with the digital control schemes.The PFC converter was applied by a single stage biflyback topology, which combined the advantages of single stage PFC and flyback topology together, with further advantages in low intermediate bus voltage and current stresses. A digital controller without current sampling requirement was proposed based on the specific topology. To reduce the voltage spike caused by the leakage inductor, a novel snubber cell combining soft switching technique with snubber technique together was proposed. Simulation and experimental waveforms illustrated the same as characteristics as the theoretical analysis.In summary, the dissertation analyzed each power stage of photovoltaic micro-inverter system from efficiency and effectiveness optimization perspectives. Moreover their advantages were compared carefully with existed topologies and control techniques. Simulation and experiment results were provided to support the theoretical analysis.
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Date Issued: 2013
Identifier: CFE0005286, ucf:50540
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005286

Title: Differential Games for Multi-Agent Systems under Distributed Information.
Creator: Lin, Wei, Qu, Zhihua, Simaan, Marwan, Haralambous, Michael, Das, Tuhin, Yong, Jiongmin, University of Central Florida
Abstract / Description: In this dissertation, we consider differential games for multi-agent systems under distributed information where every agent is only able to acquire information about the others according to a directed information graph of local communication/sensor networks. Such games arise naturally from many applications including mobile robot coordination, power system optimization, multi-player pursuit-evasion games, etc. Since the admissible strategy of each agent has to conform to the information...
Show moreIn this dissertation, we consider differential games for multi-agent systems under distributed information where every agent is only able to acquire information about the others according to a directed information graph of local communication/sensor networks. Such games arise naturally from many applications including mobile robot coordination, power system optimization, multi-player pursuit-evasion games, etc. Since the admissible strategy of each agent has to conform to the information graph constraint, the conventional game strategy design approaches based upon Riccati equation(s) are not applicable because all the agents are required to have the information of the entire system. Accordingly, the game strategy design under distributed information is commonly known to be challenging. Toward this end, we propose novel open-loop and feedback game strategy design approaches for Nash equilibrium and noninferior solutions with a focus on linear quadratic differential games. For the open-loop design, approximate Nash/noninferior game strategies are proposed by integrating distributed state estimation into the open-loop global-information Nash/noninferior strategies such that, without global information, the distributed game strategies can be made arbitrarily close to and asymptotically converge over time to the global-information strategies. For the feedback design, we propose the best achievable performance indices based approach under which the distributed strategies form a Nash equilibrium or noninferior solution with respect to a set of performance indices that are the closest to the original indices. This approach overcomes two issues in the classical optimal output feedback approach: the simultaneous optimization and initial state dependence. The proposed open-loop and feedback design approaches are applied to an unmanned aerial vehicle formation control problem and a multi-pursuer single-evader differential game problem, respectively. Simulation results of several scenarios are presented for illustration.
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Date Issued: 2013
Identifier: CFE0005025, ucf:49991
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005025

Title: Suction Detection and Feedback Control for the Rotary Left Ventricular Assist Device.
Creator: Wang, Yu, Simaan, Marwan, Qu, Zhihua, Haralambous, Michael, Kassab, Alain, Divo, Eduardo, University of Central Florida
Abstract / Description: The Left Ventricular Assist Device (LVAD) is a rotary mechanical pump that is implanted in patients with congestive heart failure to help the left ventricle in pumping blood in the circulatory system. The rotary type pumps are controlled by varying the pump motor current to adjust the amount of blood flowing through the LVAD. One important challenge in using such a device is the desire to provide the patient with as close to a normal lifestyle as possible until a donor heart becomes available...
Show moreThe Left Ventricular Assist Device (LVAD) is a rotary mechanical pump that is implanted in patients with congestive heart failure to help the left ventricle in pumping blood in the circulatory system. The rotary type pumps are controlled by varying the pump motor current to adjust the amount of blood flowing through the LVAD. One important challenge in using such a device is the desire to provide the patient with as close to a normal lifestyle as possible until a donor heart becomes available. The development of an appropriate feedback controller that is capable of automatically adjusting the pump current is therefore a crucial step in meeting this challenge. In addition to being able to adapt to changes in the patient's daily activities, the controller must be able to prevent the occurrence of excessive pumping of blood from the left ventricle (a phenomenon known as ventricular suction) that may cause collapse of the left ventricle and damage to the heart muscle and tissues.In this dissertation, we present a new suction detection system that can precisely classify pump flow patterns, based on a Lagrangian Support Vector Machine (LSVM) model that combines six suction indices extracted from the pump flow signal to make a decision about whether the pump is not in suction, approaching suction, or in suction. The proposed method has been tested using in vivo experimental data based on two different LVAD pumps. The results show that the system can produce superior performance in terms of classification accuracy, stability, learning speed, and good robustness compared to three other existing suction detection methods and the original SVM-based algorithm. The ability of the proposed algorithm to detect suction provides a reliable platform for the development of a feedback control system to control the current of the pump (input variable) while at the same time ensuring that suction is avoided.Based on the proposed suction detector, a new control system for the rotary LVAD was developed to automatically regulate the pump current of the device to avoid ventricular suction. The control system consists of an LSVM suction detector and a feedback controller. The LSVM suction detector is activated first so as to correctly classify the pump status as No Suction (NS) or Suction (S). When the detection is (")No Suction("), the feedback controller is activated so as to automatically adjust the pump current in order that the blood flow requirements of the patient's body at different physiological states are met according to the patient's activity level. When the detection is (")Suction("), the pump current is immediately decreased in order to drive the pump back to a normal No Suction operating condition. The performance of the control system was tested in simulations over a wide range of physiological conditions.
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Date Issued: 2013
Identifier: CFE0005070, ucf:49956
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0005070

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: ON THE NATURE OF THE FLOW IN A SEPARATED ANNULAR DIFFUSER.
Creator: Dunn, Jason, Kapat, Jayanta, University of Central Florida
Abstract / Description: The combustor-diffuser system remains one of the most studied sections of the turbomachine. Most of these investigations are due to the fact that quite a bit of flow diffusion is required in this section as the high speed flow exits the compressor and must be slowed down to enter the combustor. Like any diffusion process there is the chance for the development of an unfavorable adverse pressure gradient that can lead to flow separation; a cause of drastic losses within a turbine. There are...
Show moreThe combustor-diffuser system remains one of the most studied sections of the turbomachine. Most of these investigations are due to the fact that quite a bit of flow diffusion is required in this section as the high speed flow exits the compressor and must be slowed down to enter the combustor. Like any diffusion process there is the chance for the development of an unfavorable adverse pressure gradient that can lead to flow separation; a cause of drastic losses within a turbine. There are two diffusion processes in the combustor-diffuser system: The flow first exits the compressor into a pre-diffuser, or compressor discharge diffuser. This diffuser is responsible for a majority of the pressure recovery. The flow then exits the pre-diffuser by a sudden expansion into the dump diffuser. The dump diffuser comprises the majority of the losses, but is necessary to reduce the fluid velocity within acceptable limits for combustion. The topic of active flow control is gaining interest in the industry because such a technique may be able to alleviate some of the requirements of the dump diffuser. If a wider angle pre-diffuser with separation control were used the fluid velocity would be slowed more within that region without significant losses. Experiments were performed on two annular diffusers to characterize the flow separation to create a foundation for future active flow control techniques. Both diffusers had the same fully developed inlet flow condition, however, the expansion of the two diffusers differed such that one diffuser replicated a typical compressor discharge diffuser found in a real machine while the other would create a naturally separated flow along the outer wall. Both diffusers were tested at two Reynolds numbers, 5x104 and 1x105, with and without a vertical wall downstream of the exit to replicate the dump diffuser that re-directs the flow from the pre-diffuser outlet to the combustor. Static pressure measurements were obtained along the OD and ID wall of the diffusers to determine the recovered pressure throughout the diffuser. In addition to these measurements, tufts were used to visualize the flow. A turbulent CFD model was also created to compare against experimental results. In the end, the results were validated against empirical data as well as the CFD model. It was shown that the location of the vertical wall was directly related to the amount of separation as well as the separation characteristics. These findings support previous work and help guide future work for active flow control in a separated annular diffuser both computationally and experimentally.
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Date Issued: 2009
Identifier: CFE0002953, ucf:47944
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0002953

Title: EFFECT OF OPERATOR CONTROL CONFIGURATION ON UNMANNED AERIAL SYSTEM TRAINABILITY.
Creator: Neumann, John, Kincaid, Peter, University of Central Florida
Abstract / Description: Unmanned aerial systems (UAS) carry no pilot on board, yet they still require live operators to handle critical functions such as mission planning and execution. Humans also interpret the sensor information provided by these platforms. This applies to all classes of unmanned aerial vehicles (UAV's), including the smaller portable systems used for gathering real-time reconnaissance during military operations in urban terrain. The need to quickly and reliably train soldiers to control small...
Show moreUnmanned aerial systems (UAS) carry no pilot on board, yet they still require live operators to handle critical functions such as mission planning and execution. Humans also interpret the sensor information provided by these platforms. This applies to all classes of unmanned aerial vehicles (UAV's), including the smaller portable systems used for gathering real-time reconnaissance during military operations in urban terrain. The need to quickly and reliably train soldiers to control small UAS operations demands that the human-system interface be intuitive and easy to master. In this study, participants completed a series of tests of spatial ability and were then trained (in simulation) to teleoperate a micro-unmanned aerial vehicle equipped with forward and downward fixed cameras. Three aspects of the human-system interface were manipulated to assess the effects on manual control mastery and target detection. One factor was the input device. Participants used either a mouse or a specially programmed game controller (similar to that used with the Sony™ Playstation 2 video game console). A second factor was the nature of the flight control displays as either continuous or discrete (analog v. digital). The third factor involved the presentation of sensor imagery. The display could either provide streaming video from one camera at a time, or present the imagery from both cameras simultaneously in separate windows. The primary dependent variables included: 1) time to complete assigned missions, 2) number of collisions, 3) number of targets detected, and 4) operator workload. In general, operator performance was better with the game controller than with the mouse, but significant improvement in time to complete occurred over repeated trials regardless of the device used. Time to complete missions was significantly faster with the game controller, and operators also detected more targets without any significant differences in workload compared to mouse users. Workload on repeated trials decreased with practice, and spatial ability was a significant covariate of workload. Lower spatial ability associated with higher workload scores. In addition, demographic data including computer usage and video gaming experience were collected and analyzed, and correlated with performance. Higher video gaming experience was also associated with lower workload.
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Date Issued: 2006
Identifier: CFE0001496, ucf:47080
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001496

Title: IMPACT OF ZINC ORTHOPHOSPHATE INHIBITOR ONDISTRIBUTION SYSTEM WATER QUALITY.
Creator: Guan, Xiaotao, Taylor, James, University of Central Florida
Abstract / Description: This dissertation consists of four papers concerning impacts of zinc orthophosphate (ZOP) inhibitor on iron, copper and lead release in a changing water quality environment. The mechanism of zinc orthophosphate corrosion inhibition in drinking water municipal and home distribution systems and the role of zinc were investigated. Fourteen pilot distribution systems (PDSs) which were identical and consisted of increments of PVC, lined cast iron, unlined cast iron and galvanized steel pipes were...
Show moreThis dissertation consists of four papers concerning impacts of zinc orthophosphate (ZOP) inhibitor on iron, copper and lead release in a changing water quality environment. The mechanism of zinc orthophosphate corrosion inhibition in drinking water municipal and home distribution systems and the role of zinc were investigated. Fourteen pilot distribution systems (PDSs) which were identical and consisted of increments of PVC, lined cast iron, unlined cast iron and galvanized steel pipes were used in this study. Changing quarterly blends of finished ground, surface and desalinated waters were fed into the pilot distribution systems over a one year period. Zinc orthophosphate inhibitor at three different doses was applied to three PDSs. Water quality and iron, copper and lead scale formation was monitored for the one year study duration. The first article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on surface characteristics of iron corrosion products in a changing water quality environment. Surface compositions of iron surface scales for iron and galvanized steel coupons incubated in different blended waters in the presence of ZOP inhibitor were investigated using X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM) / Energy Dispersive X-ray Spectroscopy (EDS). Based on surface characterization, predictive equilibrium models were developed to describe the controlling solid phase and mechanism of ZOP inhibition and the role of zinc for iron release. The second article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on total iron release in a changing water quality environment. Development of empirical models as a function of water quality and ZOP inhibitor dose for total iron release and mass balances analysis for total zinc and total phosphorus data provided insight into the mechanism of ZOP corrosion inhibition regarding iron release in drinking water distribution systems. The third article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on total copper release in a changing water quality environment. Empirical model development was undertaken for prediction of total copper release as a function of water quality and inhibitor dose. Thermodynamic models for dissolved copper based on surface characterization of scale that were generated on copper coupons exposed to ZOP inhibitor were also developed. Surface composition was determined by X-ray Photoelectron Spectroscopy (XPS). The fourth article describes the effects of zinc orthophosphate (ZOP) corrosion inhibitor on total lead release in a changing water quality environment. Surface characterization of lead scale on coupons exposed to ZOP inhibitor by X-ray Photoelectron Spectroscopy (XPS) was utilized to identify scale composition. Development of thermodynamic model for lead release based on surface analysis results provided insight into the mechanism of ZOP inhibition and the role of zinc.
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Date Issued: 2007
Identifier: CFE0001931, ucf:47453
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001931

Title: Analysis of Remote Tripping Command Injection Attacks in Industrial Control Systems Through Statistical and Machine Learning Methods.
Creator: Timm, Charles, Caulkins, Bruce, Wiegand, Rudolf, Lathrop, Scott, University of Central Florida
Abstract / Description: In the past decade, cyber operations have been increasingly utilized to further policy goals of state-sponsored actors to shift the balance of politics and power on a global scale. One of the ways this has been evidenced is through the exploitation of electric grids via cyber means. A remote tripping command injection attack is one of the types of attacks that could have devastating effects on the North American power grid. To better understand these attacks and create detection axioms to...
Show moreIn the past decade, cyber operations have been increasingly utilized to further policy goals of state-sponsored actors to shift the balance of politics and power on a global scale. One of the ways this has been evidenced is through the exploitation of electric grids via cyber means. A remote tripping command injection attack is one of the types of attacks that could have devastating effects on the North American power grid. To better understand these attacks and create detection axioms to both quickly identify and mitigate the effects of a remote tripping command injection attack, a dataset comprised of 128 variables (primarily synchrophasor measurements) was analyzed via statistical methods and machine learning algorithms in RStudio and WEKA software respectively. While statistical methods were not successful due to the non-linearity and complexity of the dataset, machine learning algorithms surpassed accuracy metrics established in previous research given a simplified dataset of the specified attack and normal operational data. This research allows future cybersecurity researchers to better understand remote tripping command injection attacks in comparison to normal operational conditions. Further, an incorporation of the analysis has the potential to increase detection and thus mitigate risk to the North American power grid in future work.
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Date Issued: 2018
Identifier: CFE0007257, ucf:52193
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0007257

Title: The Impact of Technology on Management Control: Degradation, Empowerment, or Technology Dominance?.
Creator: Canada, Joseph, Arnold, Vicky, Roberts, Robin, Sutton, Steven, Benford, Tanya, University of Central Florida
Abstract / Description: The evolution of technology brings with it the evolution of business processes. Without a doubt, technology changes how work is performed. At first glance, workplace technology appears to be a great boon to society. However, research presents opposing views on how workplace technologies impact the individual. One perspective argues that organizations utilize technology to redesign work processes, such that the worker requires less skill, autonomy, and compensation. The opposing perspective...
Show moreThe evolution of technology brings with it the evolution of business processes. Without a doubt, technology changes how work is performed. At first glance, workplace technology appears to be a great boon to society. However, research presents opposing views on how workplace technologies impact the individual. One perspective argues that organizations utilize technology to redesign work processes, such that the worker requires less skill, autonomy, and compensation. The opposing perspective argues that organizations utilize technology to empower employees to improve efficiency and profits. This dissertation consists of three interrelated studies examining workplace technology's impact on decision makers. The first study examines the capability of an enterprise system to increase the application of scientific management techniques to middle management and, consequently, to degrade middle management's work by limiting their autonomy. The second study investigates the capability of an enterprise system to facilitate the empowerment of managers via mutual monitoring and social identification. The third study builds upon the first study by examining how limiting autonomy through technology impacts the intrinsic motivation of decision makers and, as a result, affects the decision making process. Study one applies labor process theory to explain how enterprise systems can degrade the work of middle management via scientific management techniques. The purpose of this study is to test if the expectations of labor process theory can be applied to enterprise systems. In order to test this assertion, a field survey utilizing 189 middle managers is employed and the data is analyzed using component based structural equation modeling. The results indicate that enterprise system integration increases two scientific management techniques, formalization and performance measurement, but do not reveal a significant relationship between enterprise system integration and routinization. Interestingly, the results also indicate that routinization is the only scientific management technique, of the three studied, that directly limits the autonomy of the middle managers. Although performance measurement does not reduce autonomy directly, performance measurement interacts with routinization to reduce autonomy. This study contributes to the enterprise system literature by demonstrating enterprise systems' ability to increase the degree of scientific management applied to middle management. It also contributes to labor process theory by revealing that routinization may be the scientific management technique that determines whether other control techniques are utilized in a manner consistent with labor process theory. The ability of an enterprise system to facilitate the application of Mary Parker Follett's managerial control concepts are investigated in the second study. Specifically, Follett theorizes that information sharing facilitates the internalization of group goals and empowers individuals to have more influence and be more effective. This study employs a survey of 206 managers to test the theoretical relationships. The results indicate that enterprise system integration increases information sharing in the form of mutual monitoring, consequently, leading to social identification among peer managers. Additionally, social identification among peer managers empowers managers to have more influence over the organization. The study contributes to empowerment research by acknowledging and verifying the role that social identification plays in translating an empowering work climate into empowered managers. The study's conclusion that enterprise system integration facilitates the application of Follett's managerial control concepts extends both enterprise system and managerial control literature. The third study builds upon study one by examining the affect that autonomy has upon the decision maker. This study marries self-determination theory and technology dominance theory to understand the role that self-determination, intrinsic motivation, and engagement have upon technology dominance. Self-determination theory asserts that higher degrees of self-determination increase intrinsic motivation. Furthermore, self-determination research finds that intrinsic motivation increases engagement, while technology dominance research indicates that lack of engagement is an antecedent of technology dominance. Thus, applying self-determination theory as a predictor of technology dominance suggests that autonomy and relatedness associated with a task increase the intrinsic motivation to complete that task and consequently increase engagement in the task. Task engagement, in turn, reduces the likelihood of technology dominance. The proposed theoretical model is tested experimentally with 83 junior level business students. The results do not support the theoretical model, however the findings reveal that intrinsic motivation does reduce the likelihood of technology dominance. This indicates that intrinsic motivation as a predictor of technology dominance should be further investigated. Additionally, the study contributes to technology dominance literature by exhibiting a more appropriate operationalization of the inappropriate reliance aspect of technology dominance. This dissertation reveals that various theories concerning workplace technology and management control techniques have both validity and limitations. Labor process theorists cannot assume that all technologies and management control techniques are utilized to undermine the employee's value to the organization, as Study 2 reveals that enterprise systems and mutual monitoring lead to empowered managers. Likewise, proponents of enterprise systems cannot assume that the integrated nature of enterprise systems is always utilized in an empowering manner, as Study 1 reveals the increased performance measurement through enterprise systems can be utilized to limit managers in a routinized job environment. While the third study was unable to determine that the control features in technology affect the intrinsic motivation to complete a task, the findings do reveal that intrinsic motivation is directly related to technology dominance. The findings and theoretical refinements demonstrate that workplace technology and management control have a complicated relationship with the employee and that the various theories concerning them cannot be applied universally.
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Date Issued: 2013
Identifier: CFE0004980, ucf:49569
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004980

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

Control Systems (3)	+ -
simulation (3)	+ -
Adaptive Control (2)	+ -
Synchronization (2)	+ -
control system (2)	+ -

modeling (2)	+ -
ACLU (1)	+ -
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Adaptive Traffic Control System (1)	+ -
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Angle of Arrival (1)	+ -
Automatic Detection of Abnormal Behaviour and Threats in crowded Spaces (1)	+ -
Average-car Method (1)	+ -
Before-after Study (1)	+ -
BlueMAC (1)	+ -
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University of Central Florida (30)	+ -
Das, Tuhin (5)	+ -
Haralambous, Michael (5)	+ -
Qu, Zhihua (4)	+ -
Simaan, Marwan (4)	+ -

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