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- Title
- Simulations and feedback control of nonlinear coupled electromechanical oscillators for energy conversion applications.
- Creator
- Psarrou, Dimitrios., Dhanak, Manhar R., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This thesis discusses the coupling of a mechanical and electrical oscillator, an arrangement that is often encountered in mechatronics actuators and sensors. The dynamics of this coupled system is mathematically modeled and a low pass equivalent model is presented. Numerical simulations are then performed, for various input signals to characterize the nonlinear relationship between the electrical current and the displacement of the mass. Lastly a framework is proposed to estimate the mass...
Show moreThis thesis discusses the coupling of a mechanical and electrical oscillator, an arrangement that is often encountered in mechatronics actuators and sensors. The dynamics of this coupled system is mathematically modeled and a low pass equivalent model is presented. Numerical simulations are then performed, for various input signals to characterize the nonlinear relationship between the electrical current and the displacement of the mass. Lastly a framework is proposed to estimate the mass position without the use of a position sensor, enabling the sensorless control of the coupled system and additionally providing the ability for the system to act as an actuator or a sensor. This is of value for health monitoring, diagnostics and prognostics, actuation and power transfer of a number of interconnected machines that have more than one electrical system, driving corresponding mechanical subsystems while being driven by the same voltage source and at the same time being spectrally separated and independent.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3320109
- Subject Headings
- Renewable energy sources, Mechatronics, Nonlinear theories, Oscillators, System analysis
- Format
- Document (PDF)
- Title
- Simulator and location-aware routing protocol for mobile ad hoc acoustic networks of AUVs.
- Creator
- Carlson, Edward A., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Acoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator...
Show moreAcoustic networks of autonomous underwater vehicles (AUVs) show great promise, but a lack of simulation tools and reliance on protocols originally developed for terrestrial radio networks has hindered progress. This work addresses both issues. A new simulator of underwater communication among AUVs provides accurate communication modeling and flexible vehicle behavior, while a new routing protocol, location-aware source routing (LASR) provides superior network performance. The new simulator was used to evaluate communication without networking, and then with networking using the coding or dynamic source routing (DSR) protocols. The results confirmed that a network was essential to ensure effective fleet-wide communication. The flooding protocol provided extremely reliable communication but with low message volumes. The DSR protocol, a popular routing protocol due to its effectiveness in terrestrial radio networks, proved to be a bad choice in an acoustic environment: in most cases, it suffered from both poor reliability and low message volumes. Due to the high acoustic latency, even moderate vehicle speeds caused the network topology to change faster than DSR could adapt. DSR's reliance on shortest-path routing also proved to be a significant disadvantage. Several DSR optimizations were also tested; most proved to be unhelpful or actually harmful in an underwater acoustic network. LASR was developed to address the problems noted in flooding and DSR. LASR was loosely derived from DSR, most significantly retaining source routes and the reply/request route discovery technique. However, LASR added features which proved, in simulation, to be significant advantages -- two of the most effective were a link/route metric and a node tracking system. To replace shortest-path routing, LASR used the expected transmission count (ETX) metric., This allowed LASR to make more informed routing decisions which greatly increased performance compared to DSR. The node tracking system was the most novel addition: using only implicit communication coupled with the use of time-division multiple access (TDMA), the tracking system provided predicted node locations. These predictions made it possible for LASR to proactively respond to topology changes. In most cases, LASR outperformed flooding and DSR in message delivery reliability and message delivery volume.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/187208
- Subject Headings
- Ad hoc networks (Computer networks), Computer network protocols, Routers (Computer networks), Mobile communication systems, Design and construction, Remote submersibles, Design and construction
- Format
- Document (PDF)
- Title
- Skin lesion segmentation and classification using deep learning.
- Creator
- Burdick, John B., Marques, Oge, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Melanoma, a severe and life-threatening skin cancer, is commonly misdiagnosed or left undiagnosed. Advances in artificial intelligence, particularly deep learning, have enabled the design and implementation of intelligent solutions to skin lesion detection and classification from visible light images, which are capable of performing early and accurate diagnosis of melanoma and other types of skin diseases. This work presents solutions to the problems of skin lesion segmentation and...
Show moreMelanoma, a severe and life-threatening skin cancer, is commonly misdiagnosed or left undiagnosed. Advances in artificial intelligence, particularly deep learning, have enabled the design and implementation of intelligent solutions to skin lesion detection and classification from visible light images, which are capable of performing early and accurate diagnosis of melanoma and other types of skin diseases. This work presents solutions to the problems of skin lesion segmentation and classification. The proposed classification approach leverages convolutional neural networks and transfer learning. Additionally, the impact of segmentation (i.e., isolating the lesion from the rest of the image) on the performance of the classifier is investigated, leading to the conclusion that there is an optimal region between “dermatologist segmented” and “not segmented” that produces best results, suggesting that the context around a lesion is helpful as the model is trained and built. Generative adversarial networks, in the context of extending limited datasets by creating synthetic samples of skin lesions, are also explored. The robustness and security of skin lesion classifiers using convolutional neural networks are examined and stress-tested by implementing adversarial examples.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013021
- Subject Headings
- Melanoma, Medical imaging, Deep learning, Skin diseases--Classification, Image segmentation
- Format
- Document (PDF)
- Title
- Smart Adaptive Beaconing Schemes for VANET.
- Creator
- Alhameed, Mohammed, Mahgoub, Imad, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Vehicular Ad hoc Networks (VANET) is a wireless ad-hoc network that includes two types of communications, Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I). In VANET there are two types of messages. The first type is the event-driven messages that are only triggered in case of emergency. The second type is the periodical messages named beacons that are exchanged frequently between vehicles. A beacon message contains basic information about the sending vehicle such as id, location...
Show moreVehicular Ad hoc Networks (VANET) is a wireless ad-hoc network that includes two types of communications, Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I). In VANET there are two types of messages. The first type is the event-driven messages that are only triggered in case of emergency. The second type is the periodical messages named beacons that are exchanged frequently between vehicles. A beacon message contains basic information about the sending vehicle such as id, location and velocity. Beacons are frequently exchanged to increase the cooperative awareness between vehicles. Increasing beacon frequency helps increasing neighborhood awareness and improving information accuracy. However, this causes more congestion in the network, specially when the number of vehicles increases. On the other hand, reducing beacon frequency alleviates network congestion, but results in out-dated information. In this dissertation, we address the aforementioned challenges and propose a number of smart beaconing protocols and evaluate their performance in di↵erent environments and network densities. The four adaptive beaconing protocols are designed to increase the cooperative awareness and information freshness, while alleviating the network congestion. All the proposed protocols take into account the most important aspects, which are critical to beaconing rate adaptation. These aspects include channel status, traffic conditions and link quality. The proposed protocols employ fuzzy logic-based techniques to determine the congestion rank, which is used to adjust beacon frequency. The first protocol considers signal to interference-noise ratio (SINR), number of neighboring nodes and mobility to determine the congestion rank and adjust the beacon rate accordingly. This protocol works well in sparse conditions and highway environments. The second protocol works well in sparse conditions and urban environments. It uses channel busy time (CBT), mobility and packet delivery ratio (PDR) to determine the congestion rank and adjust the beacon rate. The third protocol utilizes CBT, SINR, PDR, number of neighbors and mobility as inputs for the fuzzy logic system to determine the congestion rank and adjust the beacon rate. This protocol works well in dense conditions in both highway and urban environments. Through extensive simulation experiments, we established that certain input parameters are more e↵ective in beacon rate adaptation for certain environments and conditions. Based on this, we propose a high awareness and channel efficient scheme that adapts to di↵erent environments and conditions. First, the protocol estimates the network density using adaptive threshold function. Then, it looks at the spatial distribution of nodes using the quadrat method to determine whether the environment is highway or urban. Based on the density conditions and nodes distribution, the protocol utilizes the appropriate fuzzy input parameters to adapt the beaconing rate. In addition, the protocol optimizes the performance by adapting the transmission power based on network density and nodes distribution. Finally, an investigation of the impact of adaptive beaconing on broadcasting is conducted. The simulation results confirm that our adaptive beaconing scheme can improve performance of the broadcast protocols in terms of reachability and bandwidth consumption when compared to a fixed rate scheme.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013112
- Subject Headings
- Vehicular ad hoc networks (Computer networks), Beacons, Fuzzy logic, Adaptive computing systems
- Format
- Document (PDF)
- Title
- Smart Broadcast Protocol Design For Vehicular Ad hoc Networks.
- Creator
- Limouchi, Elnaz, Mahgoub, Imad, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Multi-hop broadcast is one of the main approaches to disseminate data in VANET. Therefore, it is important to design a reliable multi-hop broadcast protocol, which satis es both reachability and bandwidth consumption requirements. In a dense network, where vehicles are very close to each other, the number of vehicles needed to rebroadcast the message should be small enough to avoid a broad- cast storm, but large enough to meet the reachability requirement. If the network is sparse, a higher...
Show moreMulti-hop broadcast is one of the main approaches to disseminate data in VANET. Therefore, it is important to design a reliable multi-hop broadcast protocol, which satis es both reachability and bandwidth consumption requirements. In a dense network, where vehicles are very close to each other, the number of vehicles needed to rebroadcast the message should be small enough to avoid a broad- cast storm, but large enough to meet the reachability requirement. If the network is sparse, a higher number of vehicles is needed to retransmit to provide a higher reachability level. So, it is obvious that there is a tradeo between reachability and bandwidth consumption. In this work, considering the above mentioned challenges, we design a number of smart broadcast protocols and evaluate their performance in various network den- sity scenarios. We use fuzzy logic technique to determine the quali cation of vehicles to be forwarders, resulting in reachability enhancement. Then we design a band- width e cient fuzzy logic-assisted broadcast protocol which aggressively suppresses the number of retransmissions. We also propose an intelligent hybrid protocol adapts to local network density. In order to avoid packet collisions and enhance reachability, we design a cross layer statistical broadcast protocol, in which the contention window size is adjusted based on the local density information. We look into the multi-hop broadcast problem with an environment based on game theory. In this scenario, vehicles are players and their strategy is either to volunteer and rebroadcast the received message or defect and wait for others to rebroadcast. We introduce a volunteer dilemma game inspired broadcast scheme to estimate the probability of forwarding for the set of potential forwarding vehicles. In this scheme we also introduce a fuzzy logic-based contention window size adjustment system. Finally, based on the estimated spatial distribution of vehicles, we design a transmission range adaptive scheme with a fuzzy logic-assisted contention window size system, in which a bloom lter method is used to mitigate overhead. Extensive experimental work is obtained using simulation tools to evaluate the performance of the proposed schemes. The results con rm the relative advantages of the proposed protocols for di erent density scenarios.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004902, http://purl.flvc.org/fau/fd/FA00004902
- Subject Headings
- Vehicular ad hoc networks (Computer networks)--Design and construction., Mobile communication systems., Wireless communication systems--Technological innovations., Wireless sensor networks., Routing protocols (Computer network protocols), Computer algorithms.
- Format
- Document (PDF)
- Title
- Smart campus.
- Creator
- Danda, Naga Prakash, Agarwal, Ankur, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The Smart Campus project envisions a university campus where technology assists faculty, staff, students and visitors to improve and more efficiently accomplish their daily activities. The objective of this project is to develop a smart phone application that assists users in finding a certain location on campus, locating their friends and professors, interacting with any student or professors of the campus, get the count of users at certain locations and remain updated about all the events...
Show moreThe Smart Campus project envisions a university campus where technology assists faculty, staff, students and visitors to improve and more efficiently accomplish their daily activities. The objective of this project is to develop a smart phone application that assists users in finding a certain location on campus, locating their friends and professors, interacting with any student or professors of the campus, get the count of users at certain locations and remain updated about all the events and campus news. Through this project, an idea of ‘Futuristic Social Network’ in a Campus is modeled and developed on Android platform.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004098, http://purl.flvc.org/fau/fd/FA00004098
- Subject Headings
- Mobile communication systems -- Security measures, Technological innovations -- Social aspects, Ubiquitous computing, Universities and colleges -- Design
- Format
- Document (PDF)
- Title
- Smart low power obstacle avoidance device.
- Creator
- Cividanes, Ernesto., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Several technologies are being made available for the blind and the visually impaired with the use of infrared and sonar sensors, Radio Frequency Identification, GPS, Wi-Fi among others. Current technologies utilizing microprocessors increase the device's power consumption. In this project, a Verilog Hardware Language (VHDL) designed handheld device that autonomously guides a visually impaired user through an obstacle free path is proposed. The goal is to minimize power consumption by not...
Show moreSeveral technologies are being made available for the blind and the visually impaired with the use of infrared and sonar sensors, Radio Frequency Identification, GPS, Wi-Fi among others. Current technologies utilizing microprocessors increase the device's power consumption. In this project, a Verilog Hardware Language (VHDL) designed handheld device that autonomously guides a visually impaired user through an obstacle free path is proposed. The goal is to minimize power consumption by not using the usual microcontroller and replacing it with components that can increase its speed. Utilizing six infrared sensors, the handheld device is modeled after current technologies which use IR and sonar sensors which are reviewed in this project. By using behavioral modeling, an algorithm for obstacle avoidance and the generation of the obstacle free path is reduced using a K-map and implemented using a multiplexer.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2954841
- Subject Headings
- Verilog (Computer hardware description language), VHDL (Computer hardware description language), Rapid prototyping, Logic design, Intelligent control systems, Brain-computer interfaces
- Format
- Document (PDF)
- Title
- SMARTPHONE BASED SICKLE CELL DISEASE DETECTION AND ITS TREATMENT MONITORING FOR POINT-OF-CARE SETTINGS.
- Creator
- Ilyas, Shazia, Asghar, Waseem, Florida Atlantic University, Department of Computer and Electrical Engineering and Computer Science, College of Engineering and Computer Science
- Abstract/Description
-
The majority of Sickle Cell Disease (SCD) prevalence is found in Sub-Saharan Africa, where 80% of the world’s population who suffer from this disease are born. Due to a lack of diagnosis and early treatments, 50-90% of these children will die before they reach the age of five. Current methods used for diagnosing SCD are based on hemoglobin analysis such as capillary electrophoresis, ion-exchange high-performance liquid chromatography, and isoelectric focusing. They require expensive...
Show moreThe majority of Sickle Cell Disease (SCD) prevalence is found in Sub-Saharan Africa, where 80% of the world’s population who suffer from this disease are born. Due to a lack of diagnosis and early treatments, 50-90% of these children will die before they reach the age of five. Current methods used for diagnosing SCD are based on hemoglobin analysis such as capillary electrophoresis, ion-exchange high-performance liquid chromatography, and isoelectric focusing. They require expensive laboratory equipment and are not feasible in these low-resource countries. It is, therefore, imperative to develop an alternative and cost-effective method for diagnosing and monitoring of SCD. This thesis aims to address the development and evaluation of a smartphone-based optical setup for the detection of SCD. This innovative technique can potentially be applied for low cost and accurate diagnosis of SCD and improve disease management in resource-limited settings where the disease exhibits a high prevalence. This Point-of-Care (POC) based device offers the potential to improve SCD diagnosis and patient care by providing a portable and cost effective device that requires minimal training to operate and analyze.
Show less - Date Issued
- 2020
- PURL
- http://purl.flvc.org/fau/fd/FA00013475
- Subject Headings
- Anemia, Sickle Cell, Point-of-Care Systems, Sickle cell anemia--Treatment, Sickle cell anemia--Diagnosis, Smartphones
- Format
- Document (PDF)
- Title
- Soft Robotics: Fiber Reinforced Soft Pneumatic Multidirectional Manipulators, Designing, Fabricating, and Testing.
- Creator
- Holdar, Mohammad, Engeberg, Erik, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Traditional robots are made from hard materials like hard plastic or metal and consist of regular rigid mechanical parts. Using those parts has some limitations, like limited dexterity and lack of flexibility. Some of these limitations could be avoided through using a compliant material, because it has higher flexibility and dexterity. It is also safer to be in direct contact with humans. This thesis studies soft pneumatic manipulators (SPMs) that move in multi degrees of freedom (MDOF),...
Show moreTraditional robots are made from hard materials like hard plastic or metal and consist of regular rigid mechanical parts. Using those parts has some limitations, like limited dexterity and lack of flexibility. Some of these limitations could be avoided through using a compliant material, because it has higher flexibility and dexterity. It is also safer to be in direct contact with humans. This thesis studies soft pneumatic manipulators (SPMs) that move in multi degrees of freedom (MDOF), which makes them able to perform various functions. The study will include designing, fabricating, and testing three different SPMs with different taper angles -- 0^0, 1^0, and 2^0 -- to measure the effect of varying this geometry on the achievable force by the end effector and the range of bending and elongation. Every single SPM consists of three soft pneumatic chambers to reach unlimited points on its workspace through implementing bending and elongating movements. There are a lot of applications for this kind of soft actuators, like rehabilitation, underwater utilizes, and robots for surgery and rescues. Most soft pneumatic actuators provide one kind of movement, for bending, twisting, or elongating. Combining more than one kind of movement in one soft pneumatic actuator provides considerable contributions to the body of research. The SPMs were controlled and tested to evaluate the achieved force and two kinds of movement, bending and elongating range. The results of each module has been compared with the others to determine which actuator has the best performance. Then a force controller was created to maintain the desired force that was achieved by the end effector. The results indicated that the optimal angle of the SPM was 2^0.
Show less - Date Issued
- 2018
- PURL
- http://purl.flvc.org/fau/fd/FA00013030
- Subject Headings
- Robotics, Pneumatic control, Actuators--Design and construction, Soft robotics
- Format
- Document (PDF)
- Title
- Software design using case based reasoning.
- Creator
- Smith, Nancy T., Florida Atlantic University, Ganesan, Krishnamurthy, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The project that was created for this thesis is a Case Based Reasoning application to be used in high level software design for Siemens' Telecommunications software. Currently, design engineers search for existing subtasks in the software that are similar to subtasks in their new designs by reading documentation and consulting with other engineers. The prototype for Software Design Using Case Based Reasoning (SDUCBR) stores these subtasks in a case library and enables the design engineer to...
Show moreThe project that was created for this thesis is a Case Based Reasoning application to be used in high level software design for Siemens' Telecommunications software. Currently, design engineers search for existing subtasks in the software that are similar to subtasks in their new designs by reading documentation and consulting with other engineers. The prototype for Software Design Using Case Based Reasoning (SDUCBR) stores these subtasks in a case library and enables the design engineer to locate relevant subtasks via three different indexing techniques. This thesis addresses knowledge representation and indexing mechanisms appropriate for this application. SDUCBR is domain-dependent. Cases are stored in a relational hierarchy to facilitate analyzing the existing implementation from various perspectives. The indexing mechanisms were designed to provide the software design engineer with the flexibility of describing a problem differently based on the objective, level of granularity, and special characteristics of the subtask.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/15198
- Subject Headings
- Computer software--Development, Case-based reasoning, Artificial intelligence--Data processing, System design
- Format
- Document (PDF)
- Title
- Software development for ecological data systems.
- Creator
- Lostal, Sergio L., Florida Atlantic University, Larrondo-Petrie, Maria M., Solomon, Martin K., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Software development for ecological data systems is concentrated in the description, modeling, and standardization of large amounts of ecological data. Ecological data assembled in many formats is very difficult to reuse. This thesis develops a database model that supports the storage of heterogeneous data in standardized formats. Ecological data standardization is solved with the specification of a structure conversion system. Because input formats cannot be predicted, a scientific data...
Show moreSoftware development for ecological data systems is concentrated in the description, modeling, and standardization of large amounts of ecological data. Ecological data assembled in many formats is very difficult to reuse. This thesis develops a database model that supports the storage of heterogeneous data in standardized formats. Ecological data standardization is solved with the specification of a structure conversion system. Because input formats cannot be predicted, a scientific data description language was created to control the execution of the conversion system. System analysis is based on interviews with South Florida Water Management District scientists conducting ecosystem research, and ecological data collected at Lake Okeechobee, Florida, during a five-year study. Object-oriented and structural methods were used for analysis. Development is complemented with an introduction to user interfaces.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/15344
- Subject Headings
- Ecology--Data processing, Information storage and retrieval systems--Ecology, Okeechobee, Lake (Fla)
- Format
- Document (PDF)
- Title
- Software development of a hardware-in-the-loop simulation and a three-dimensional viewer for autonomous underwater vehicles.
- Creator
- Mahieu, Frederi., Florida Atlantic University, An, Edgar, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
This thesis describes the development of the hardware-in-the-loop simulation for FAU Autonomous Underwater Vehicles. The development was based on the existing simulation platform. For more efficiency and flexibility, this simulation package was ported to Linux. The hardware-in-the-loop simulation enables developers to connect the vehicle directly to a remote simulator. This kind of simulation is used to test the actual software components embedded in the vehicle system. The simulation package...
Show moreThis thesis describes the development of the hardware-in-the-loop simulation for FAU Autonomous Underwater Vehicles. The development was based on the existing simulation platform. For more efficiency and flexibility, this simulation package was ported to Linux. The hardware-in-the-loop simulation enables developers to connect the vehicle directly to a remote simulator. This kind of simulation is used to test the actual software components embedded in the vehicle system. The simulation package was enhanced by the addition of a 3D viewer. This thesis describes the whole development process, from feasibility study and implementation to qualification phases. This viewer is platform independent and designed to be connected to the simulator. It renders the AUV moving in a virtual environment. This tool can be used during all development steps, from tuning phases to post-mission analysis.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/15778
- Subject Headings
- Oceanographic submersibles--Computer simulation, Computer software--Development, Simulation methods, Three-dimensional display systems
- Format
- Document (PDF)
- Title
- Software fault prediction using tree-based models.
- Creator
- Seliya, Naeem A., Florida Atlantic University, Khoshgoftaar, Taghi M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Maintaining superior quality and reliability in software systems is of utmost importance in today's world. Early fault prediction is a proven method for achieving this. Tree based modelling is a simple and effective method that can be used to predict the number of faults in a software system. In this thesis, we use regression tree based modelling to predict the number of faults in a software module. The goal of this study is four-fold. First, a comparative study of the tree based modelling...
Show moreMaintaining superior quality and reliability in software systems is of utmost importance in today's world. Early fault prediction is a proven method for achieving this. Tree based modelling is a simple and effective method that can be used to predict the number of faults in a software system. In this thesis, we use regression tree based modelling to predict the number of faults in a software module. The goal of this study is four-fold. First, a comparative study of the tree based modelling tools CART and S-PLUS. CART yielded simpler regression trees than those built by S-PLUS. Second, a comparative study of the least squares and the least absolute deviation methods of CART. It is shown that the latter yielded better results than the former. Third, a study of the possible benefits of using principal components analysis when performing regression tree modelling. The fourth and final study is a comparison of tree based modelling with other prediction techniques namely, Case Based Reasoning, Artificial Neural Networks and Multiple Linear Regression.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12782
- Subject Headings
- Software measurement, Computer software--Quality control
- Format
- Document (PDF)
- Title
- Software framework for prognostic health monitoring of ocean-based power generation.
- Creator
- Bowren, Mark., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
On August 5, 2010 the U.S. Department of Energy (DOE) has designated the Center for Ocean Energy Technology (COET) at Florida Atlantic University (FAU) as a national center for ocean energy research and development of prototypes for open-ocean power generation. Maintenance on ocean-based machinery can be very costly. To avoid unnecessary maintenance it is necessary to monitor the condition of each machine in order to predict problems. This kind of prognostic health monitoring (PHM) requires a...
Show moreOn August 5, 2010 the U.S. Department of Energy (DOE) has designated the Center for Ocean Energy Technology (COET) at Florida Atlantic University (FAU) as a national center for ocean energy research and development of prototypes for open-ocean power generation. Maintenance on ocean-based machinery can be very costly. To avoid unnecessary maintenance it is necessary to monitor the condition of each machine in order to predict problems. This kind of prognostic health monitoring (PHM) requires a condition-based maintenance (CBM) system that supports diagnostic and prognostic analysis of large amounts of data. Research in this field led to the creation of ISO13374 and the development of a standard open-architecture for machine condition monitoring. This thesis explores an implementation of such a system for ocean-based machinery using this framework and current open-standard technologies.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3342035
- Subject Headings
- Machinery, Monitoring, Marine turbines, Mathematical models, Fluid dynamics, Structural dynamics
- Format
- Document (PDF)
- Title
- Software quality classification using rule-based modeling.
- Creator
- Mao, Meihui., Florida Atlantic University, Khoshgoftaar, Taghi M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Software-based products are part of our daily life. They can be encountered in most of the systems we interact with. This reliance on software products generates a strong need for better software reliability, reducing the cost associated with potential failures. Reliability in software systems may be achieved by using additional testing. However, extensive software testing is expensive and time consuming. Software quality classification models provide an early prediction of a module's quality...
Show moreSoftware-based products are part of our daily life. They can be encountered in most of the systems we interact with. This reliance on software products generates a strong need for better software reliability, reducing the cost associated with potential failures. Reliability in software systems may be achieved by using additional testing. However, extensive software testing is expensive and time consuming. Software quality classification models provide an early prediction of a module's quality. Boolean Discriminant Function (BDF), Generalized Boolean Discriminant Function (GBDF), and Rule-Based Modeling (RBM) can be used as classification models. This thesis demonstrates the ability of GBDF and RBM to correctly classify modules. The introduction of the AND operator in the GBDF model and the customizable outcomes for the rules in RBM, enhanced the discriminating quality of GBDF and RBM as compared to BDF. Furthermore, they also yielded better balances for the misclassification rates.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12886
- Subject Headings
- Computer software--Quality control, Software measurement
- Format
- Document (PDF)
- Title
- Software quality modeling and analysis with limited or without defect data.
- Creator
- Seliya, Naeem A., Florida Atlantic University, Khoshgoftaar, Taghi M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The key to developing high-quality software is the measurement and modeling of software quality. In practice, software measurements are often used as a resource to model and comprehend the quality of software. The use of software measurements to understand quality is accomplished by a software quality model that is trained using software metrics and defect data of similar, previously developed, systems. The model is then applied to estimate quality of the target software project. Such an...
Show moreThe key to developing high-quality software is the measurement and modeling of software quality. In practice, software measurements are often used as a resource to model and comprehend the quality of software. The use of software measurements to understand quality is accomplished by a software quality model that is trained using software metrics and defect data of similar, previously developed, systems. The model is then applied to estimate quality of the target software project. Such an approach assumes that defect data is available for all program modules in the training data. Various practical issues can cause an unavailability or limited availability of defect data from the previously developed systems. This dissertation presents innovative and practical techniques for addressing the problem of software quality analysis when there is limited or completely absent defect data. The proposed techniques for software quality analysis without defect data include an expert-based approach with unsupervised clustering and an expert-based approach with semi-supervised clustering. The proposed techniques for software quality analysis with limited defect data includes a semi-supervised classification approach with the Expectation-Maximization algorithm and an expert-based approach with semi-supervised clustering. Empirical case studies of software measurement datasets obtained from multiple NASA software projects are used to present and evaluate the different techniques. The empirical results demonstrate the attractiveness, benefit, and definite promise of the proposed techniques. The newly developed techniques presented in this dissertation is invaluable to the software quality practitioner challenged by the absence or limited availability of defect data from previous software development experiences.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/12151
- Subject Headings
- Software measurement, Computer software--Quality control, Computer software--Reliability--Mathematical models, Software engineering--Quality control
- Format
- Document (PDF)
- Title
- Software reliability engineering with genetic programming.
- Creator
- Liu, Yi., Florida Atlantic University, Khoshgoftaar, Taghi M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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Software reliability engineering plays a vital role in managing and controlling software quality. As an important method of software reliability engineering, software quality estimation modeling is useful in defining a cost-effective strategy to achieve a reliable software system. By predicting the faults in a software system, the software quality models can identify high-risk modules, and thus, these high-risk modules can be targeted for reliability enhancements. Strictly speaking, software...
Show moreSoftware reliability engineering plays a vital role in managing and controlling software quality. As an important method of software reliability engineering, software quality estimation modeling is useful in defining a cost-effective strategy to achieve a reliable software system. By predicting the faults in a software system, the software quality models can identify high-risk modules, and thus, these high-risk modules can be targeted for reliability enhancements. Strictly speaking, software quality modeling not only aims at lowering the misclassification rate, but also takes into account the costs of different misclassifications and the available resources of a project. As a new search-based algorithm, Genetic Programming (GP) can build a model without assuming the size, shape, or structure of a model. It can flexibly tailor the fitness functions to the objectives chosen by the customers. Moreover, it can optimize several objectives simultaneously in the modeling process, and thus, a set of multi-objective optimization solutions can be obtained. This research focuses on building software quality estimation models using GP. Several GP-based models of predicting the class membership of each software module and ranking the modules by a quality factor were proposed. The first model of categorizing the modules into fault-prone or not fault-prone was proposed by considering the distinguished features of the software quality classification task and GP. The second model provided quality-based ranking information for fault-prone modules. A decision tree-based software classification model was also proposed by considering accuracy and simplicity simultaneously. This new technique provides a new multi-objective optimization algorithm to build decision trees for real-world engineering problems, in which several trade-off objectives usually have to be taken into account at the same time. The fourth model was built to find multi-objective optimization solutions by considering both the expected cost of misclassification and available resources. Also, a new goal-oriented technique of building module-order models was proposed by directly optimizing several goals chosen by project analysts. The issues of GP , bloating and overfitting, were also addressed in our research. Data were collected from three industrial projects, and applied to validate the performance of the models. Results indicate that our proposed methods can achieve useful performance results. Moreover, some proposed methods can simultaneously optimize several different objectives of a software project management team.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fau/fd/FADT12047
- Subject Headings
- Computer software--Quality control, Genetic programming (Computer science), Software engineering
- Format
- Document (PDF)
- Title
- Software-implemented fault tolerance in a hypercube multiprocessor.
- Creator
- Sahai, Shankar., Florida Atlantic University, Fernandez, Eduardo B., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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This thesis analyzes how software fault tolerance can be implemented in a hypercube multiprocessor. For concreteness we consider a multiprocessor using Intel 80286/386/486 processors. The Recovery Metaprogram approach (an architecture that isolates all fault tolerance functions in a special layer) has been used to implement application transparent and application specific fault tolerance technigues such as recovery blocks, N-version programming, exceptions and others. A fault tolerant routing...
Show moreThis thesis analyzes how software fault tolerance can be implemented in a hypercube multiprocessor. For concreteness we consider a multiprocessor using Intel 80286/386/486 processors. The Recovery Metaprogram approach (an architecture that isolates all fault tolerance functions in a special layer) has been used to implement application transparent and application specific fault tolerance technigues such as recovery blocks, N-version programming, exceptions and others. A fault tolerant routing algorithm is also described. While the details are specific to the 80286/386/486 processor these results apply also to any other processor with similar features.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14633
- Subject Headings
- Hypercube networks (Computer networks), Intel 80x86 (Microprocessor)
- Format
- Document (PDF)
- Title
- Soil-geosynthetic reinforcement interaction for mechanically stabilized earth (MSE) wall systems.
- Creator
- Navarrete, Fernando Manuel., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
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The dissertation is an experimental and analytical investigation of the long term performance of mechanically stabilized earth (MSE) walls with geosynthetics, with particular focus on rational methods to enable the determination of the applicable factors for use in Load Resistance Factor Design (LRFD). An overview of current issues concerning MSE walls is followed by an extensive literature review addressing MSE walls, pullout strength, creep and creep rupture, durability and degradation,...
Show moreThe dissertation is an experimental and analytical investigation of the long term performance of mechanically stabilized earth (MSE) walls with geosynthetics, with particular focus on rational methods to enable the determination of the applicable factors for use in Load Resistance Factor Design (LRFD). An overview of current issues concerning MSE walls is followed by an extensive literature review addressing MSE walls, pullout strength, creep and creep rupture, durability and degradation, design methodology, analytical prediction, and field evaluation of MSE walls. The experimental tasks comprise: (i) creep and creep rupture, (ii) durability and degradation, (iii) small scale testing of MSE walls with a model prototype ratio of 1:5.5, and (iv) construction of prototype MSE wall and instrumentation for long-term performance. The analytical work comprises finite difference modeling using the Fast Lagrangian Analysis of Continua (FLAC) software, (i) For creep up to 10,000 hours accelerated exposure for HDPE and PET geogrids, with super-ambient temperatures and soil water conditions related to soil conditions in Florida, the significant part of creep was due to temperatures and not solution exposures, with creep rupture occurring primarily for HDPE. (ii) For durability, performance at ambient temperatures was extrapolated, based on the Arrhenius method. The variation in degradation between the different solutions was minimal, indicating hydrolysis as the main cause for PET at elevated temperatures. (iii) Two HDPE and two PET reinforcement small scale (1:5.5) MSE walls were tested, with different surcharges each for 72 hour periods. Panel movements, strains in the reinforcement, and wall settlements were measured, indicating values smaller than the predicted, mostly for the smaller surcharges due to distortion caused by scaling neglecting the gravity effect. (iv) For analysis with FLAC computer software, two correction factors "a" and "b" were applied to correct the discrepancies between the model and the test values. The PET MSE small scale wall showed more deviation because the material has a low modulus of elasticity. (v) A preliminary comparison of the small scale and the prototype MSE wall behavior indicated discrepancies due to distortion scaling related to the lack of gravity simulation.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/11968
- Subject Headings
- Geosynthetics, Load factor design, Retaining walls, Soil stabilization
- Format
- Document (PDF)
- Title
- Solar cell degradation under ionizing radiation ambient: preemptive testing and evaluation via electrical overstressing.
- Creator
- Thengum Pallil, George A., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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The efforts addressed in this thesis refer to assaying the degradations in modern solar cells used in space-borne and/or nuclear environment applications. This study is motivated to address the following: 1. Modeling degradations in Si pn-junction solar cells (devices-under-test or DUTs) under different ionizing radiation dosages 2. Preemptive and predictive testing to determine the aforesaid degradations that decide eventual reliability of the DUTs; and 3. Using electrical overstressing (EOS...
Show moreThe efforts addressed in this thesis refer to assaying the degradations in modern solar cells used in space-borne and/or nuclear environment applications. This study is motivated to address the following: 1. Modeling degradations in Si pn-junction solar cells (devices-under-test or DUTs) under different ionizing radiation dosages 2. Preemptive and predictive testing to determine the aforesaid degradations that decide eventual reliability of the DUTs; and 3. Using electrical overstressing (EOS) to emulate the fluence of ionizing radiation dosage on the DUT. Relevant analytical methods, computational efforts and experimental studies are described. Forward/reverse characteristics as well as ac impedance performance of a set of DUTs under pre- and post- electrical overstressings are evaluated. Change in observed DUT characteristics are correlated to equivalent ionizing-radiation dosages. The results are compiled and cause-effect considerations are discussed. Conclusions are enumerated and inferences are made with direction for future studies.
Show less - Date Issued
- 2010
- PURL
- http://purl.flvc.org/FAU/2979384
- Subject Headings
- Renewable energy sources, Solar cells, Effect of radiation on, Reliability (Engineering), Electric discharges, Ionizing radiation
- Format
- Document (PDF)