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- Title
- Application of MANOVA and Mahalanobis Distance in quality control.
- Creator
- Seth, Mahua., Florida Atlantic University, Mazouz, Abdel Kader, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Many quality control problems are multivariate in nature since multiple process or product variables are measured and monitored in modern industry. Occasionally a multiple population, multi-variable scenario is encountered in parallel line manufacturing system. This work deals with the analysis of such system using multivariate techniques such as Canonical Analysis, MANOVA and Mahalanobis Distance. Using such techniques, the significant differences between the populations and the magnitude...
Show moreMany quality control problems are multivariate in nature since multiple process or product variables are measured and monitored in modern industry. Occasionally a multiple population, multi-variable scenario is encountered in parallel line manufacturing system. This work deals with the analysis of such system using multivariate techniques such as Canonical Analysis, MANOVA and Mahalanobis Distance. Using such techniques, the significant differences between the populations and the magnitude and directions of the variations within and between the populations were determined. Also, elimination/reduction of such variations using multivariate techniques led to a drastic improvement of the production system. A methodology for application of such multivariate techniques for the purpose of quality assurance and improvement was developed here. The application of this methodology was performed on a pager production line and the results obtained show the benefits and the feasibility of the use of multivariate techniques for on-line monitoring and quality control.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15381
- Subject Headings
- Quality control, Beepers--Quality control, Process control
- Format
- Document (PDF)
- Title
- Design and tuning of fuzzy control surface with Bezier functions.
- Creator
- Wongsoontorn, Songwut., Florida Atlantic University, Zhuang, Hanqi, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Design and Tuning a fuzzy logic controller (FLCs) are usually done in two stages. In the first stage, the structure of a FLC is determined based on physical characteristics of the system. In the second stage, the parameters of the FLC are selected to optimize the performance of the system. The task of tuning FLCs can be performed by a number of methods such as adjusting control gains, changing membership functions, modifying control rules and varying control surfaces. A method for the design...
Show moreDesign and Tuning a fuzzy logic controller (FLCs) are usually done in two stages. In the first stage, the structure of a FLC is determined based on physical characteristics of the system. In the second stage, the parameters of the FLC are selected to optimize the performance of the system. The task of tuning FLCs can be performed by a number of methods such as adjusting control gains, changing membership functions, modifying control rules and varying control surfaces. A method for the design and tuning of FLCs through modifying their control surfaces is presented in this dissertation. The method can be summarized as follows. First, fuzzy control surfaces are modeled with Bezier functions. Shapes of the control surface are then adjusted through varying Bezier parameters. A Genetic Algorithm (GA) is used to search for the optimal set of parameters based on the control performance criteria. Then, tuned control surfaces are sampled to create rule-based FLCs. To further improve the system performance, continuity constraints of the curves are imposed. Under the continuity constraints with the same number of tunable parameters, one can obtain more flexible curves that have the potential to improve the overall system performance. An important issue is to develop a new method to self-tune a fuzzy PD controller. The method is based on two building blocks: (I) Bezier functions used to model the control surfaces of the fuzzy PD controller; and, shapes of control surfaces are then adjusted by varying Bezier parameters. (II) The next step involves using a gradient-based optimization algorithm with which the input scaling factors and Bezier parameters are on-line tuned until the controller drives the output of the process as close as possible to the reference position. To protect vendors and consumers from being victimized, various trust models have been used in e-commerce practices. However, a strict verification and authentication process may pose unnecessary heavy cost to the vendor. As an application of the control strategy proposed, this dissertation presents a solution to the reduction of costs of a vendor. With two fuzzy variables (price, credit-history), a trust-surface can be tuned to achieve an optimal solution in terms of profit margin of the vendor. With this new approach, more realistic trust decisions can be reached.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/12172
- Subject Headings
- Fuzzy systems, Nonlinear control theory, Process control--Data processing, Fuzzy logic, Intelligent control systems
- Format
- Document (PDF)
- Title
- Design and implementation of intelligent control methodologies for reverse osmosis plants.
- Creator
- Jafar, Mutaz M., Florida Atlantic University, Zilouchian, Ali, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This dissertation presents the design, implementation and application of soft computing methodologies to Reverse Osmosis (RO) desalination technology. A novel intelligent control scheme based on the integration of Neural Network (NN) and Fuzzy Logic (FL) is presented to optimize plants' performance. In the first part of the research work, two optimal NN predictive models, based on backpropagation and Radial Basis Function Networks (RBFN), were developed for three types of RO feed intakes. The...
Show moreThis dissertation presents the design, implementation and application of soft computing methodologies to Reverse Osmosis (RO) desalination technology. A novel intelligent control scheme based on the integration of Neural Network (NN) and Fuzzy Logic (FL) is presented to optimize plants' performance. In the first part of the research work, two optimal NN predictive models, based on backpropagation and Radial Basis Function Networks (RBFN), were developed for three types of RO feed intakes. The predictive models utilized actual operating data for the three RO plants in order to predict system recovery, total dissolved solids and ion product concentration in brine stream A predictive model is proposed based on redistributed receptive fields of RBFN. The proposed algorithm utilizes integration of supervised learning of centers and unsupervised learning of output layer weights. Extensive simulations are presented to demonstrate the effectiveness of the proposed method for generalization on prediction of nonlinear input-output mappings. In the second part of the study, the design of FL control strategy for direct seawater RO system is carried out. The real-time controller design is based on integration of sensory information, predicted outputs, mathematical calculations, and expert knowledge of the process to yield a constant recovery, constant salt rejection and minimum scaling under variable operating conditions. To implement the designed methodology, a 250/800 Gallon per Day (GPD) prototype RO plant with direct Atlantic Ocean intake is constructed at FAU Gumbo Limbo research laboratory. Two types of membrane modules were used for this study: Spiral Wound (SW) and Hollow Fine Fiber (HFF). The prototype plant indeed demonstrated the effectiveness and optimum performance of the proposed design under variable operating conditions. The system achieved a constant recovery of 30% and salt passage of 1.026% while ion product concentration for six major salts were kept below their solubility limits at all time. The implementation of the proposed intelligent control methodology achieved a 4% increase in availability and a 50% reduction in manpower requirements, as well as reduction in overall chemical consumption of the plant. Therefore, it is expected that the cost of producing fresh water from seawater desalination will be decreased using the proposed intelligent control strategy.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/12650
- Subject Headings
- Saline water conversion--Reverse osmosis process, Intelligent control systems
- Format
- Document (PDF)
- Title
- Nonlinear control of an unmanned amphibious vehicle.
- Creator
- Alvarez, Jose L., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The DUCKW-Ling is an 8.3 foot long, amphibious water plane area twin hull (SWATH) concept vehicle which is propelled by a pair of crawler tracks on land and dual propellers when water-borne. In its operational zone, the vehicle's dynamics change dramatically as it transitions from being completely water-borne and buoyancy supported to being completely land-borne and track supported. In the water environment, a cascaded, first-order sliding mode controller was used to control the surge and...
Show moreThe DUCKW-Ling is an 8.3 foot long, amphibious water plane area twin hull (SWATH) concept vehicle which is propelled by a pair of crawler tracks on land and dual propellers when water-borne. In its operational zone, the vehicle's dynamics change dramatically as it transitions from being completely water-borne and buoyancy supported to being completely land-borne and track supported. In the water environment, a cascaded, first-order sliding mode controller was used to control the surge and heading of the vehicle, and was capable of having a faster response when compared to using a proportional controller. Additionally, field trials of the DUKW-Ling show the capability of the vehicle to navigate and track predetermined waypoints in both terrestrial and aquatic terrains. In the transitional zone, the electric motor current from the tracks was used as the feedback mechanism to adequately actuate the propellers and tracks in the system as the dynamics of the vehicle change.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3362334
- Subject Headings
- Nonlinear control theory, Feedback control systems, Motor vehicles, Amphibious, Design and construction, Adaptive signal processing
- Format
- Document (PDF)
- Title
- Data Quality in Data Mining and Machine Learning.
- Creator
- Van Hulse, Jason, Khoshgoftaar, Taghi M., Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
With advances in data storage and data transmission technologies, and given the increasing use of computers by both individuals and corporations, organizations are accumulating an ever-increasing amount of information in data warehouses and databases. The huge surge in data, however, has made the process of extracting useful, actionable, and interesting knowled_qe from the data extremely difficult. In response to the challenges posed by operating in a data-intensive environment, the fields of...
Show moreWith advances in data storage and data transmission technologies, and given the increasing use of computers by both individuals and corporations, organizations are accumulating an ever-increasing amount of information in data warehouses and databases. The huge surge in data, however, has made the process of extracting useful, actionable, and interesting knowled_qe from the data extremely difficult. In response to the challenges posed by operating in a data-intensive environment, the fields of data mining and machine learning (DM/ML) have successfully provided solutions to help uncover knowledge buried within data. DM/ML techniques use automated (or semi-automated) procedures to process vast quantities of data in search of interesting patterns. DM/ML techniques do not create knowledge, instead the implicit assumption is that knowledge is present within the data, and these procedures are needed to uncover interesting, important, and previously unknown relationships. Therefore, the quality of the data is absolutely critical in ensuring successful analysis. Having high quality data, i.e., data which is (relatively) free from errors and suitable for use in data mining tasks, is a necessary precondition for extracting useful knowledge. In response to the important role played by data quality, this dissertation investigates data quality and its impact on DM/ML. First, we propose several innovative procedures for coping with low quality data. Another aspect of data quality, the occurrence of missing values, is also explored. Finally, a detailed experimental evaluation on learning from noisy and imbalanced datasets is provided, supplying valuable insight into how class noise in skewed datasets affects learning algorithms.
Show less - Date Issued
- 2007
- PURL
- http://purl.flvc.org/fau/fd/FA00000858
- Subject Headings
- Data mining--Quality control, Machine learning, Electronic data processing--Quality control
- Format
- Document (PDF)
- Title
- A simplistic approach to reactive multi-robot navigation in unknown environments.
- Creator
- MacKunis, William Thomas., Florida Atlantic University, Raviv, Daniel, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Multi-agent control is a very promising area of robotics. In applications for which it is difficult or impossible for humans to intervene, the utilization of multi-agent, autonomous robot groups is indispensable. This thesis presents a novel approach to reactive multi-agent control that is practical and elegant in its simplicity. The basic idea upon which this approach is based is that a group of robots can cooperate to determine the shortest path through a previously unmapped environment by...
Show moreMulti-agent control is a very promising area of robotics. In applications for which it is difficult or impossible for humans to intervene, the utilization of multi-agent, autonomous robot groups is indispensable. This thesis presents a novel approach to reactive multi-agent control that is practical and elegant in its simplicity. The basic idea upon which this approach is based is that a group of robots can cooperate to determine the shortest path through a previously unmapped environment by virtue of redundant sharing of simple data between multiple agents. The idea was implemented with two robots. In simulation, it was tested with over sixty agents. The results clearly show that the shortest path through various environments emerges as a result of redundant sharing of information between agents. In addition, this approach exhibits safeguarding techniques that reduce the risk to robot agents working in unknown and possibly hazardous environments. Further, the simplicity of this approach makes implementation very practical and easily expandable to reliably control a group comprised of many agents.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13013
- Subject Headings
- Robots--Control systems, Intelligent control systems, Genetic algorithms, Parallel processing (Electronic computers)
- Format
- Document (PDF)
- Title
- A reduced delay OPAC system.
- Creator
- Kaskawits, Stuart Jay., Florida Atlantic University, Pajunen, Grazyna, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Implementation of the Optimized Policies for Adaptive Control (OPAC) strategy in conjunction with a vehicle velocity controller offers the potential for significantly improving the control strategies used at isolated intersections with respect to measured vehicle delays. The exhaustive sequential search procedure by OPAC provides the optimal switching policies for the intersection while the vehicle velocity controller varies vehicle velocities to reduce vehicle stopping delays. The OPAC...
Show moreImplementation of the Optimized Policies for Adaptive Control (OPAC) strategy in conjunction with a vehicle velocity controller offers the potential for significantly improving the control strategies used at isolated intersections with respect to measured vehicle delays. The exhaustive sequential search procedure by OPAC provides the optimal switching policies for the intersection while the vehicle velocity controller varies vehicle velocities to reduce vehicle stopping delays. The OPAC algorithm implemented with the vehicle velocity controller was found to have substantially lower delays than OPAC alone.
Show less - Date Issued
- 1994
- PURL
- http://purl.flvc.org/fcla/dt/15072
- Subject Headings
- Adaptive control systems, Traffic engineering--Data processing, Traffic flow, Electronic traffic controls
- Format
- Document (PDF)
- Title
- Detection of multiple change-points in hazard models.
- Creator
- Zhang, Wei, Qian, Lianfen, Florida Atlantic University, Charles E. Schmidt College of Science, Department of Mathematical Sciences
- Abstract/Description
-
Change-point detection in hazard rate function is an important research topic in survival analysis. In this dissertation, we firstly review existing methods for single change-point detection in piecewise exponential hazard model. Then we consider the problem of estimating the change point in the presence of right censoring and long-term survivors while using Kaplan-Meier estimator for the susceptible proportion. The maximum likelihood estimators are shown to be consistent. Taking one step...
Show moreChange-point detection in hazard rate function is an important research topic in survival analysis. In this dissertation, we firstly review existing methods for single change-point detection in piecewise exponential hazard model. Then we consider the problem of estimating the change point in the presence of right censoring and long-term survivors while using Kaplan-Meier estimator for the susceptible proportion. The maximum likelihood estimators are shown to be consistent. Taking one step further, we propose an counting process based and least squares based change-point detection algorithm. For single change-point case, consistency results are obtained. We then consider the detection of multiple change-points in the presence of long-term survivors via maximum likelihood based and counting process based method. Last but not least, we use a weighted least squares based and counting process based method for detection of multiple change-points with long-term survivors and covariates. For multiple change-points detection, simulation studies show good performances of our estimators under various parameters settings for both methods. All methods are applied to real data analyses.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004173
- Subject Headings
- Problem solving--Data processing., Process control--Statistical methods., Point processes., Mathematical statistics., Failure time data analysis--Data processing., Survival analysis (Biometry)--Data processing.
- Format
- Document (PDF)
- Title
- Design considerations in high-throughput automation for biotechnology protocols.
- Creator
- Cardona, Aura, Roth, Zvi S., Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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In this dissertation a computer-aided automation design methodology for biotechnology applications is proposed that leads to several design guidelines. Because of the biological nature of the samples that propagate in the automation line, a very specific set of environmental and maximum allowed shelf time conditions have to be followed to obtain good yield. In addition all biotechnology protocols require precise sequence of steps, the samples are scarce and the reagents are costly, so no...
Show moreIn this dissertation a computer-aided automation design methodology for biotechnology applications is proposed that leads to several design guidelines. Because of the biological nature of the samples that propagate in the automation line, a very specific set of environmental and maximum allowed shelf time conditions have to be followed to obtain good yield. In addition all biotechnology protocols require precise sequence of steps, the samples are scarce and the reagents are costly, so no waste can be afforded.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004272, http://purl.flvc.org/fau/fd/FA00004272
- Subject Headings
- Biotechnological process control, Biotechnological process monitoring, Molecular biology -- Automation, Molecular biology -- Technique, Molecular cloning -- Technique, Pharmacognosy
- Format
- Document (PDF)
- Title
- The directionality of noise created by turbulent flow over roughness.
- Creator
- Kaufman, Gerard P., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Flow over a rough surface is known to radiate sound as a dipole source that is directional. In order to better understand this source, measurements are being made in a wind tunnel using a microphone array. The measurements collected by a microphone array are beamformed to give a source image and can be deconvolved with an assumed point spread function in order to obtain the source levels. This thesis considers alternative analysis algorithms that can be used to analyze wind tunnel data. Only...
Show moreFlow over a rough surface is known to radiate sound as a dipole source that is directional. In order to better understand this source, measurements are being made in a wind tunnel using a microphone array. The measurements collected by a microphone array are beamformed to give a source image and can be deconvolved with an assumed point spread function in order to obtain the source levels. This thesis considers alternative analysis algorithms that can be used to analyze wind tunnel data. Only numerical examples of how these algorithms work will be presented and the analysis of real data will be considered in later studies. It will be shown how estimates can be made of the source directivity by comparing the measured data with a theoretical source model and minimizing the error between the model and the measurements.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3171394
- Subject Headings
- Electromagnetic fields, Signal processing, Digital techniques, Noise control, Adaptive signal processing, Acoustic emission, Measurement
- Format
- Document (PDF)
- Title
- Automated Launch and Recovery of an Autonomous Underwater Vehicle from an Unmanned Surface Vessel.
- Creator
- Sarda, Edoardo I, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
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Research on collaboration among unmanned platforms is essential to improve the applications for autonomous missions, by expanding the working environment of the robotic systems, and reducing the risks and the costs associated with conducting manned operations. This research is devoted to enable the collaboration between an Unmanned Surface Vehicle (USV) and an Autonomous Underwater Vehicle (AUV), by allowing the first one to launch and recover the second one. The objective of this...
Show moreResearch on collaboration among unmanned platforms is essential to improve the applications for autonomous missions, by expanding the working environment of the robotic systems, and reducing the risks and the costs associated with conducting manned operations. This research is devoted to enable the collaboration between an Unmanned Surface Vehicle (USV) and an Autonomous Underwater Vehicle (AUV), by allowing the first one to launch and recover the second one. The objective of this dissertation is to identify possible methods to launch and recover a REMUS 100 AUV from a WAM-V 16 USV, thus developing this capability by designing and implementing a launch and recovery system (LARS). To meet this objective, a series of preliminary experiments was first performed to identify two distinct methods to launch and recover the AUV: mobile and semi-stationary. Both methods have been simulated using the Orcaflex software. Subsequently, the necessary control systems to create the mandatory USV autonomy for the purpose of launch and recovery were developed. Specifically, a series of low-level controllers were designed and implemented to enable two autonomous maneuvers on the USV: station-keeping and speed & heading control. In addition, a level of intelligence to autonomously identify the optimal operating conditions within the vehicles' working environment, was derived and integrated on the USV. Lastly, a LARS was designed and implemented on the vehicles to perform the operation following the proposed methodology. The LARS and all subsystems developed for this research were extensively tested through sea-trials. The methodology for launch and recovery, the design of the LARS and the experimental findings are reported in this document.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004631, http://purl.flvc.org/fau/fd/FA00004631
- Subject Headings
- Underwater acoustic telemetry., Fuzzy systems., Nonlinear control theory., Adaptive signal processing., Oceanographic submersibles--Automatic control., Submersibles--Control systems.
- Format
- Document (PDF)
- Title
- A high-level fuzzy logic guidance system for an unmanned surface vehicle (USV) tasked to perform an autonomous launch and recovery (ALR) of an unmanned underwater vehicle (UUV).
- Creator
- Pearson, David, An, Pak-Cheung, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
There have been much technological advances and research in Unmanned Surface Vehicles (USV) as a support and delivery platform for Autonomous/Unmanned Underwater Vehicles (AUV/UUV). Advantages include extending underwater search and survey operations time and reach, improving underwater positioning and mission awareness, in addition to minimizing the costs and risks associated with similar manned vessel operations. The objective of this thesis is to present the design and development a high...
Show moreThere have been much technological advances and research in Unmanned Surface Vehicles (USV) as a support and delivery platform for Autonomous/Unmanned Underwater Vehicles (AUV/UUV). Advantages include extending underwater search and survey operations time and reach, improving underwater positioning and mission awareness, in addition to minimizing the costs and risks associated with similar manned vessel operations. The objective of this thesis is to present the design and development a high-level fuzzy logic guidance controller for a WAM-V 14 USV in order to autonomously launch and recover a REMUS 100 AUV. The approach to meeting this objective is to develop ability for the USV to intercept and rendezvous with an AUV that is in transit in order to maximize the probability of a final mobile docking maneuver. Specifically, a fuzzy logic Rendezvous Docking controller has been developed that generates Waypoint-Heading goals for the USV to minimize the cross-track errors between the USV and AUV. A subsequent fuzzy logic Waypoint-Heading controller has been developed to provide the desired heading and speed commands to the low-level controller given the Waypoint-Heading goals. High-level mission control has been extensively simulated using Matlab and partially characterized in real-time during testing. Detailed simulation, experimental results and findings will be reported in this paper.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004315, http://purl.flvc.org/fau/fd/FA00004315
- Subject Headings
- Adaptive signal processing, Fuzzy sets, Fuzzy systems, Nonlinear control theory, Oceanographic submersibles -- Automatic control, Submersibles -- Control systems, Underwater acoustic telemetry
- Format
- Document (PDF)
- Title
- Wind Feedforward Control of a USV.
- Creator
- Qu, Huajin, von Ellenrieder, Karl, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
In this research, a wind feedforward (FF) controller has been developed to augment closed loop feedback controllers for the position and heading station keeping control of Unmanned Surface Vehicles (USVs). The performance of the controllers was experimentally tested using a 16 foot USV in an outdoor marine environment. The FF controller was combined with three nonlinear feedback controllers, a Proportional–Derivative (PD) controller, a Backstepping (BS) controller, and a Sliding mode (SM)...
Show moreIn this research, a wind feedforward (FF) controller has been developed to augment closed loop feedback controllers for the position and heading station keeping control of Unmanned Surface Vehicles (USVs). The performance of the controllers was experimentally tested using a 16 foot USV in an outdoor marine environment. The FF controller was combined with three nonlinear feedback controllers, a Proportional–Derivative (PD) controller, a Backstepping (BS) controller, and a Sliding mode (SM) controller, to improve the station-keeping performance of the USV. To address the problem of wind model uncertainties, adaptive wind feedforward (AFF) control schemes are also applied to the FF controller, and implemented together with the BS and SM feedback controllers. The adaptive law is derived using Lyapunov Theory to ensure stability. On-water station keeping tests of each combination of FF and feedback controllers were conducted in the U.S. Intracoastal Waterway in Dania Beach, FL USA. Five runs of each test condition were performed; each run lasted at least 10 minutes. The experiments were conducted in Sea State 1 with an average wind speed of between 1 to 4 meters per second and significant wave heights of less than 0.2 meters. When the performance of the controllers is compared using the Integral of the Absolute Error (IAE) of position criterion, the experimental results indicate that the BS and SM feedback controllers significantly outperform the PD feedback controller (e.g. a 33% and a 44% decreases in the IAE, respectively). It is also found that FF is beneficial for all three feedback controllers and that AFF can further improve the station keeping performance. For example, a BS feedback control combined with AFF control reduces the IAE by 25% when compared with a BS feedback controller combined with a non-adaptive FF controller. Among the eight combinations of controllers tested, SM feedback control combined with AFF control gives the best station keeping performance with an average position and heading error of 0.32 meters and 4.76 degrees, respectively.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004623, http://purl.flvc.org/fau/fd/FA00004623
- Subject Headings
- Wind turbines--Control., Adaptive control systems., Adaptive signal processing., Intelligent control systems., Wind-pressure., Intelligent sensors.
- Format
- Document (PDF)
- Title
- Spectral refinement to speech enhancement.
- Creator
- Charoenruengkit, Werayuth., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The goal of a speech enhancement algorithm is to remove noise and recover the original signal with as little distortion and residual noise as possible. Most successful real-time algorithms thereof have done in the frequency domain where the frequency amplitude of clean speech is estimated per short-time frame of the noisy signal. The state of-the-art short-time spectral amplitude estimator algorithms estimate the clean spectral amplitude in terms of the power spectral density (PSD) function...
Show moreThe goal of a speech enhancement algorithm is to remove noise and recover the original signal with as little distortion and residual noise as possible. Most successful real-time algorithms thereof have done in the frequency domain where the frequency amplitude of clean speech is estimated per short-time frame of the noisy signal. The state of-the-art short-time spectral amplitude estimator algorithms estimate the clean spectral amplitude in terms of the power spectral density (PSD) function of the noisy signal. The PSD has to be computed from a large ensemble of signal realizations. However, in practice, it may only be estimated from a finite-length sample of a single realization of the signal. Estimation errors introduced by these limitations deviate the solution from the optimal. Various spectral estimation techniques, many with added spectral smoothing, have been investigated for decades to reduce the estimation errors. These algorithms do not address significantly issue on quality of speech as perceived by a human. This dissertation presents analysis and techniques that offer spectral refinements toward speech enhancement. We present an analytical framework of the effect of spectral estimate variance on the performance of speech enhancement. We use the variance quality factor (VQF) as a quantitative measure of estimated spectra. We show that reducing the spectral estimator VQF reduces significantly the VQF of the enhanced speech. The Autoregressive Multitaper (ARMT) spectral estimate is proposed as a low VQF spectral estimator for use in speech enhancement algorithms. An innovative method of incorporating a speech production model using multiband excitation is also presented as a technique to emphasize the harmonic components of the glottal speech input., The preconditioning of the noisy estimates by exploiting other avenues of information, such as pitch estimation and the speech production model, effectively increases the localized narrow-band signal-to noise ratio (SNR) of the noisy signal, which is subsequently denoised by the amplitude gain. Combined with voicing structure enhancement, the ARMT spectral estimate delivers enhanced speech with sound clarity desirable to human listeners. The resulting improvements in enhanced speech are observed to be significant with both Objective and Subjective measurement.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/186327
- Subject Headings
- Adaptive signal processing, Digital techniques, Spectral theory (Mathematics), Noise control, Fuzzy algorithms, Speech processing systems, Digital techniques
- Format
- Document (PDF)
- Title
- Wind effect on super-tall buildings using computational fluid dynamics and structural dynamics.
- Creator
- Assaad, Bilal, Arockiasamy, Madasamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
Super-tall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 7-10 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of...
Show moreSuper-tall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 7-10 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of Computational Fluid Dynamics has created an additional layer of analysis and loading prediction alternative to conventional methods. The present document uses turbulence modeling and numerical algorithms by means of Reynolds-averaged Navier-Stokes and Large Eddy Simulation equations applied to a square prismatic prototype structure in which its dynamic properties have also been investigated. With proper modeling of the atmospheric boundary layer flow, these numerical techniques reveal important aerodynamic properties and enhance flow visualization to structural engineers in a virtual environment.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004343, http://purl.flvc.org/fau/fd/FA00004343
- Subject Headings
- Boundary layer control, Buildings -- Aerodynamics, Computational fluid dynamics, Structural dynamics -- Data processing, Vortex motion
- Format
- Document (PDF)
- Title
- Content-based image retrieval using relevance feedback.
- Creator
- Marques, Oge, Florida Atlantic University, Furht, Borko, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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This dissertation presents the results of research that led to the development of a complete, fully functional, image search and retrieval system with relevance feedback capabilities, called MUSE (MUltimedia SEarch and Retrieval Using Relevance Feedback). Two different models for searching for a target image using relevance feedback have been proposed, implemented, and tested. The first model uses a color-based feature vector and employs a Bayesian learning algorithm that updates the...
Show moreThis dissertation presents the results of research that led to the development of a complete, fully functional, image search and retrieval system with relevance feedback capabilities, called MUSE (MUltimedia SEarch and Retrieval Using Relevance Feedback). Two different models for searching for a target image using relevance feedback have been proposed, implemented, and tested. The first model uses a color-based feature vector and employs a Bayesian learning algorithm that updates the probability of each image in the database being the target based on the user's actions. The second model uses cluster analysis techniques, a combination of color-, texture-, and edge(shape)-based features, and a novel approach to learning the user's goals and the relevance of each feature for a particular search. Both models follow a purely content-based image retrieval paradigm. The search process is based exclusively on image contents automatically extracted during the (off-line) feature extraction stage. Moreover, they minimize the number and complexity of required user's actions, in contrast with the complexity of the underlying search and retrieval engine. Results of experiments show that both models exhibit good performance for moderate-size, unconstrained databases and that a combination of the two outperforms any of them individually, which is encouraging. In the process of developing this dissertation, we also implemented and tested several image features and similarity measurement combinations. The result of these tests---performed under the query-by-example (QBE) paradigm---served as a reference in the choice of which features to use in the relevance feedback mode and confirmed the difficulty in encoding the understanding of image similarity into a combination of features and distances without human assistance. Most of the code written during the development of this dissertation has been encapsulated into a multifunctional prototype that combines image searching (with or without an example), browsing, and viewing capabilities and serves as a framework for future research in the subject.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/11954
- Subject Headings
- Information storage and retrieval systems, Image processing--Digital techniques, Feedback control systems
- Format
- Document (PDF)
- Title
- Parallel-computing concepts and methods toward large-scale floquet analysis of helicopter trim and stability.
- Creator
- Nakadi, Rajesh Mohan., Florida Atlantic University, Gaonkar, Gopal H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
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The rotorcraft trim solution involves a search for control inputs for required flight conditions as well as for corresponding initial conditions for periodic response or orbit. The control inputs are specified indirectly to satisfy flight conditions of prescribed thrust levels, rolling and pitching moments etc. In addition to the nonlinearity of the equations of motion and control inputs, the control inputs appear not only in damping and stiffness matrices but also in the forcing-function or...
Show moreThe rotorcraft trim solution involves a search for control inputs for required flight conditions as well as for corresponding initial conditions for periodic response or orbit. The control inputs are specified indirectly to satisfy flight conditions of prescribed thrust levels, rolling and pitching moments etc. In addition to the nonlinearity of the equations of motion and control inputs, the control inputs appear not only in damping and stiffness matrices but also in the forcing-function or input matrix; they must be found concomitantly with the periodic response from external constraints on the flight conditions. The Floquet Transition Matrix (FTM) is generated for perturbations about that periodic response; usually, a byproduct of the trim analysis. The damping levels or stability margins are computed from an eigenanalysis of the FTM. The Floquet analysis comprises the trim analysis and eigenanalysis and is routinely used for small order systems (order N < 100). However, it is practical for neither design applications nor comprehensive analysis models that lead to large systems (N > 100); the execution time on a sequential computer is prohibitive. The trim analysis takes the bulk of this execution time. Accordingly, this thesis develops concepts and methods of parallelism toward Floquet analysis of large systems with computational reliability comparable to that of sequential computations. A parallel shooting scheme with damped Newton iteration is developed for the trim analysis. The scheme uses parallel algorithms of Runge-Kutta integration and linear equations solution. A parallel QR algorithm is used for the eigenanalysis of the FTM. Additional parallelism in each iteration cycle is achieved by concurrent operations such as perturbations of initial conditions and control inputs, follow-up integrations and formations of the columns of the Jacobian matrix. These parallel shooting and eigenanalysis schemes are applied to the nonlinear flap-lag stability with a three-dimensional dynamic wake (N ~ 150). The stability also is investigated by widely used sequential schemes of shooting with damped Newton iteration and QR eigenanalysis. The computational reliability is quantified by the maximum condition number of the Jacobian matrices in the Newton iteration, the eigenvalue condition numbers and the residual errors of the eigenpairs. The saving in computer time is quantified by the speedup, which is the ratio of the execution times of Floquet analysis by sequential and parallel schemes. The work is carried out on massively parallel MasPar MP-1, a distributed-memory, single-instruction multiple-data or SIMD computer. A major finding is that with increasing system order, while the parallel execution time remains nearly constant, the sequential execution time increases nearly cubically with N. Thus, parallelism promises to make large-scale Floquet analysis practical.
Show less - Date Issued
- 1994
- PURL
- http://purl.flvc.org/fcla/dt/15085
- Subject Headings
- Floquet theory, Helicopters--Control systems, Rotors (Helicopters), Parallel processing (Electronic computers)
- Format
- Document (PDF)
- Title
- Frequency Line Tracking in Spectrograms Using Hidden Markov Models.
- Creator
- Gunes, Tuncay, Erdol, Nurgun, Florida Atlantic University
- Abstract/Description
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One of the limiting factors restricting aircraft landings at maJor airports is the minimum spacing requirements due to vortex wake avoidance. If it can be shown that the separation requirements are too conservative, then it may be possible to increase the rate of landings on a given runway. During August/September 2003, NASA and the (United States Department of Transportation) USDOT sponsored a wake acoustics test at the Denver International Airport. The central instrument of the test was a...
Show moreOne of the limiting factors restricting aircraft landings at maJor airports is the minimum spacing requirements due to vortex wake avoidance. If it can be shown that the separation requirements are too conservative, then it may be possible to increase the rate of landings on a given runway. During August/September 2003, NASA and the (United States Department of Transportation) USDOT sponsored a wake acoustics test at the Denver International Airport. The central instrument of the test was a large microphone phased array. Different types of aircrafts were recorded during landing and the acoustic data obtained was stored. From acoustic data the spectrograms were generated using the technique of AutoRegressive (AR) spectral estimation from multitaper autocorrelation estimates. Several sources of sound that are recorded in the audio files can be observed in the spectrograms. Some these signals, such as the noise generated from the aircraft engine can be identified easily because of their strength and the Doppler shift they undergo. In contrast to this, the wake vortex signal is weaker and does not exhibit a Doppler shift because it's stationary in space. Therefore it may not be identified easily because of the existence of stronger signals. The motive in our research is to develop methods to determine these strong signals that appear as spectral lines in the spectrogram. In the future, the results obtained in this work can be used to eliminate these strong signals from the spectrogram thus allowing us to see and identify wake vortex signal which is more important to us.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fau/fd/FA00012525
- Subject Headings
- Markov processes, Economics--Mathematical models, Wave structure function--Analysis, Adaptive control systems, Spectrum analysis
- Format
- Document (PDF)
- Title
- Interactive computer aided digital control design.
- Creator
- Yakali, Huseyin Hakan., Florida Atlantic University, Roth, Zvi S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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This thesis outlines the design philosophy and implementation aspects of a new interactive CAD tool implemented in BASIC language on an IBM PC/AT computer for single input single output (SISO) digital control systems. The direct Digital Control design method presented is classical in nature. The program main features are: (1) The use of Modified z-transform to model the effects of transport delay due to control computation time. (2) The use of windows on a split screen to allow the designer...
Show moreThis thesis outlines the design philosophy and implementation aspects of a new interactive CAD tool implemented in BASIC language on an IBM PC/AT computer for single input single output (SISO) digital control systems. The direct Digital Control design method presented is classical in nature. The program main features are: (1) The use of Modified z-transform to model the effects of transport delay due to control computation time. (2) The use of windows on a split screen to allow the designer observation of the closed-loop step response while systematically shaping a root locus or synthesizing closed-loop pole/zero patterns. (3) Display of system response in between sampling instants.
Show less - Date Issued
- 1988
- PURL
- http://purl.flvc.org/fcla/dt/14488
- Subject Headings
- Computer-aided design, Digital control systems, Engineering design--Data processing
- Format
- Document (PDF)
- Title
- An ultrareliable multicomputer architecture for real time control applications.
- Creator
- Buechler, Peter Charles., Florida Atlantic University, Fernandez, Eduardo B.
- Abstract/Description
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This thesis considers the design of ultrareliable multicomputers for control applications. The fault tolerance problem is divided into three subproblems: software, processing node, and communication fault tolerance. Design is performed using layers of abstraction, with fault tolerance implemented by dedicated layers. For software fault tolerance, new constructs for concurrent n-version programming are introduced. For processing node fault tolerance, the distributed fault tolerance (DFT)...
Show moreThis thesis considers the design of ultrareliable multicomputers for control applications. The fault tolerance problem is divided into three subproblems: software, processing node, and communication fault tolerance. Design is performed using layers of abstraction, with fault tolerance implemented by dedicated layers. For software fault tolerance, new constructs for concurrent n-version programming are introduced. For processing node fault tolerance, the distributed fault tolerance (DFT) concept of Chen and Chen is extended to allow for arbitrary failures. Communication fault tolerance is achieved with multicasting on a fault-tolerant graph (FG) network. Reliability models are developed for each of the layers, and a performance model is developed for the communication layer. An example flight control system is compared to currently existing architectures.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/14573
- Subject Headings
- Computers--Reliability, Fault-tolerant computing, Real-time data processing, Flight control
- Format
- Document (PDF)