Current Search: College of Engineering and Computer Science (x)
View All Items
Pages
- Title
- Adaptive controller design for an autonomous twin-hulled surface vessel with uncertain displacement and drag.
- Creator
- Klinger, Wilhelm B., von Ellenrieder, Karl, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The design and validation of a low-level backstepping controller for speed and heading that is adaptive in speed for a twin-hulled underactuated unmanned surface vessel is presented. Consideration is given to the autonomous launch and recovery of an underwater vehicle in the decision to pursue an adaptive control approach. Basic system identification is conducted and numerical simulation of the vessel is developed and validated. A speed and heading controller derived using the backstepping...
Show moreThe design and validation of a low-level backstepping controller for speed and heading that is adaptive in speed for a twin-hulled underactuated unmanned surface vessel is presented. Consideration is given to the autonomous launch and recovery of an underwater vehicle in the decision to pursue an adaptive control approach. Basic system identification is conducted and numerical simulation of the vessel is developed and validated. A speed and heading controller derived using the backstepping method and a model reference adaptive controller are developed and ultimately compared through experimental testing against a previously developed control law. Experimental tests show that the adaptive speed control law outperforms the non-adaptive alternatives by as much as 98% in some cases; however heading control is slightly sacrificed when using the adaptive speed approach. It is found that the adaptive control law is the best alternative when drag and mass properties of the vessel are time-varying and uncertain.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004130, http://purl.flvc.org/fau/fd/FA00004130
- Subject Headings
- Adaptive control systems, Drag (Aerodynamics), Intelligent control systems, Intelligent control systems, Vehicles, Remotely piloted
- Format
- Document (PDF)
- Title
- Adaptive energy-aware real-time detection models for cardiac atrial fibrillation.
- Creator
- Bouhenguel, Redjem., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Though several clinical monitoring ways exist and have been applied to detect cardiac atril fibrillation (A-Fib) and other arrhythmia, these medical interventions and the ensuing clinical treatments are after the fact and costly. Current portable healthcare monitoring systems come in the form of Ambulatory Event Monitors. They are small, battery-operated electrocardiograph devices used to record the heart's rhythm and activity. However, they are not energy-aware ; they are not personalized ;...
Show moreThough several clinical monitoring ways exist and have been applied to detect cardiac atril fibrillation (A-Fib) and other arrhythmia, these medical interventions and the ensuing clinical treatments are after the fact and costly. Current portable healthcare monitoring systems come in the form of Ambulatory Event Monitors. They are small, battery-operated electrocardiograph devices used to record the heart's rhythm and activity. However, they are not energy-aware ; they are not personalized ; they require long battery life, and ultimately fall short on delivering real-time continuous detection of arrhythmia and specifically progressive development of cardiac A-Fib. The focus of this dissertation is the design of a class of adaptive and efficient energy-aware real-time detection models for monitoring, early real-time detection and reporting of progressive development of cardiac A-Fib.... The design promises to have a greater positive public health impact from predicting A-Fib and providing a viable approach to meeting the energy needs of current and future real-time monitoring, detecting and reporting required in wearable computing healthcare applications that are constrained by scarce energy resources.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3358332
- Subject Headings
- Medical informatics, Medicine, Data processing, Imaging systems in medicine, Design and construction, Cardiovascular system, Diseases, Diagnosis, Bioinformatics
- Format
- Document (PDF)
- Title
- Adaptive hierarchical weighted fair queuing scheduling in WiMAX networks.
- Creator
- AL-Ghanem, Waleed Khalid, Ilyas, Mohammad, Mahgoub, Imad, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The growing demand for faster connection to the Internet service and wireless multimedia applications has motivated the development of broadband wireless access technologies in recent years. WiMAX has enabled convergence of mobile and fixed broadband networks through a common wide-area radio-access technology and flexible network architecture. Scheduling is a fundamental component in resource management in WiMAX networks and plays the main role in meeting QoS requirements such as delay,...
Show moreThe growing demand for faster connection to the Internet service and wireless multimedia applications has motivated the development of broadband wireless access technologies in recent years. WiMAX has enabled convergence of mobile and fixed broadband networks through a common wide-area radio-access technology and flexible network architecture. Scheduling is a fundamental component in resource management in WiMAX networks and plays the main role in meeting QoS requirements such as delay, throughput and packet loss for different classes of service. In this dissertation work, the performance of uplink schedulers at the fixed WiMAX MAC layer has been considered, we proposed an Adaptive Hierarchical Weighted Fair Queuing Scheduling algorithm, the new scheduling algorithm adapts to changes in traffic, at the same time; it is able to heuristically enhance the performance of WiMAX network under most circumstances. The heuristic nature of this scheduling algorithm enables the MAC layer to meet the QoS requirements of the users. The performance of this adaptive WiMAX Uplink algorithm has been evaluated by simulation using MATLAB. Results indicate that the algorithm is efficient in scheduling the Base Stations’ traffic loads, and improves QoS. The utilization of relay stations is studied and simulation results are compared with the case without using relay stations. The results show that the proposed scheduling algorithm improves Quality of Service of WiMAX system.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004178, http://purl.flvc.org/fau/fd/FA00004178
- Subject Headings
- Computer networks -- Technological innovations, Optical fiber communication, Wireless communication systems -- Technological innovations, Wireless metropolitan area networks -- Security measures
- Format
- Document (PDF)
- Title
- ADAPTIVE HYBRID MULTIPLE ACCESS PROTOCOLS WITH SATELLITE NETWORK APPLICATIONS.
- Creator
- SARDANA, KARAMVIR., Florida Atlantic University, Ilyas, Mohammad, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
A general and broad new class, ART, consisting of adaptive hybrid multiple access protocols applicable to communication networks sharing a single transmission medium and which behave like A loha-type, R eservation and T DMA basic protocols at low, medium and high throughput respectively, is proposed. Each hybrid protocol in this class is a combination of one protocol, possibly individually adaptive or improved version, from each of these three basic classes of protocols. Specifically, for...
Show moreA general and broad new class, ART, consisting of adaptive hybrid multiple access protocols applicable to communication networks sharing a single transmission medium and which behave like A loha-type, R eservation and T DMA basic protocols at low, medium and high throughput respectively, is proposed. Each hybrid protocol in this class is a combination of one protocol, possibly individually adaptive or improved version, from each of these three basic classes of protocols. Specifically, for satellite communication networks, a sub-class of ART protocols called Adaptive Satellite Hybrid Access (ASHA)+ is proposed.Two ASHA protocols named ASHA1 and ASHA2 that combine the features of S-ALOHA, TDMA-Reservation and TDMA protocols by using a proposed generalized design technique, are described in detail and their analytical models are formulated. The ASHA protocols are analyzed using Equilibrium Point Analysis technique and then their analytical results are presented. A fairly sophisticated and new simulator, modeled basically as a 3-state finite state machine, to simulate the ASHA protocols is designed, described and implemented. A new phenomenon called "protocol oscillations" is observed, in which a hybrid protocol oscillates back and forth between its two adjacent states without accomplishing much, and becomes literally unstable. Traffic measures and threshold values to remedy this problem are discussed. As a by-product of simulator validation, it is found that SRUC protocol, previously thought to be stable at all traffic levels, also suffers from this problem. In addition, some previous simulation results of SRUC protocol are felt not to be correct, and its simulation results that we believe to be correct instead, are given. Detailed simulation results of ASHA protocols are presented and also compared with their analytical results. These results provide a large amount of practical and valuable insight, heretofore unknown, into the workings of adaptive hybrid protocols in general and of ASHA protocols in particular. Moreover, these results show that ASHA protocols provide better delay versus throughput performance over the entire range of throughput compared to any of their individual constituent protocols, and extend the channel capacity to unity. ftn$\sp+$As an aside, ASHA means "hope" in Hindi language.
Show less - Date Issued
- 1987
- PURL
- http://purl.flvc.org/fcla/dt/11907
- Subject Headings
- Computer network protocols, Artificial satellites in telecommunication
- Format
- Document (PDF)
- Title
- Adaptive on-demand routing protocol for mobile ad hoc networks.
- Creator
- Omer, Ismail., Florida Atlantic University, Mahgoub, Imad, Ilyas, Mohammad, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Existing MANET routing protocols can be classified into three categories: On-demand, Proactive, and Proactive-On-demand hybrid protocols. This dissertation presents a novel hybrid MANET routing protocol, Adaptive On-demand MANET Routing (AOMAR) protocol. AOMAR borrowed the concepts of temporal location updates in operating systems and cache memories to reconstruct broken routes. Each route entry in a mobile host will have a reference field that is set to indicate whether the route is used...
Show moreExisting MANET routing protocols can be classified into three categories: On-demand, Proactive, and Proactive-On-demand hybrid protocols. This dissertation presents a novel hybrid MANET routing protocol, Adaptive On-demand MANET Routing (AOMAR) protocol. AOMAR borrowed the concepts of temporal location updates in operating systems and cache memories to reconstruct broken routes. Each route entry in a mobile host will have a reference field that is set to indicate whether the route is used within a certain period of time called refresh time. Using the refresh time parameter and the route reference field, AOMAR behavior can be controlled to behave as pure On-demand, Adaptive, or history related Proactive protocol. The three versions of AOMAR, On-demand, Adaptive and Proactive, have been simulated using different network sizes, loads and mobility patterns. Three performance metrics---throughput, delay and overhead---are collected. The results show that AOMAR on-demand has the same pattern of results when compared with other exiting on-demand protocols. On-demand AOMAR shows better performance when compared to Adaptive AOMAR for simulation sessions with uniform workloads. On the other hand Adaptive AOMAR outperforms On-demand AOMAR for simulation sessions with non-uniform workloads. Proactive AOMAR reconstructs recently used routes that have broken. Therefore, its routing overhead results change with the change of the network loads and mobility rates. This is not the case for traditional proactive protocols. Proactive AOMAR has lower control overhead and saves the bandwidth when compared with traditional existing proactive routing protocols. In addition to developing and simulating AOMAR, a new mobility model is proposed. Synchronized Random Direction Model of Motion with Constant Speed (SRDMCS) is a model that is suitable to emulate objects that move in random directions with a constant speed and within a certain area of movement. A new formula, Movement Related Update (MRU), is proposed and implemented. In MRU, the refresh period parameter value is linked to the network mobility level. Using MRU in the simulation gives AOMAR a third dimension such that the protocol not only adapts with how frequently the routes are used and how frequently they are broken, but also with how dynamic the network is.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/11972
- Subject Headings
- Mobile computing, Computer network protocols, Wireless communication systems
- Format
- Document (PDF)
- Title
- Adaptive power control in 802.11 networks.
- Creator
- Dural, Serkan., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
IEEE 802.11 networks successfully satisfy high data demands and are cheaper compared to cellular networks. Modern mobile computers and phones are equipped with 802.11 and are VoIP capable. Current network designs do not dynamically accommodate changes in the usage. We propose a dynamic power control algorithm that provides greater capacity within a limited geographic region. Most other power algorithms necessitate changes in 802.11 requiring hardware changes. Proposed algorithm only requires...
Show moreIEEE 802.11 networks successfully satisfy high data demands and are cheaper compared to cellular networks. Modern mobile computers and phones are equipped with 802.11 and are VoIP capable. Current network designs do not dynamically accommodate changes in the usage. We propose a dynamic power control algorithm that provides greater capacity within a limited geographic region. Most other power algorithms necessitate changes in 802.11 requiring hardware changes. Proposed algorithm only requires firmware updates to enable dynamic control of APs transmit power. We use earlier studies to determine the limit of the number of users to optimize power. By lowering transmit power of APs with large number of users, we can effectively decrease the cell size. The resulting gap is then covered by dynamically activating additional APs. This also provides greater flexibility and reduces the network planning costs.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/221941
- Subject Headings
- IEEE 802.11 (Standard), Computer networks, Security measures, Computer network protocols, Mobile communication systems, Power supply
- Format
- Document (PDF)
- Title
- Adaptive Routing Protocols for VANET.
- Creator
- Skiles, Joanne, Mahgoub, Imad, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
A Vehicular Ad-hoc Network (VANET) is a wireless ad-hoc network that provides communications among vehicles with on-board units and between vehicles and nearby roadside units. The success of a VANET relies on the ability of a routing protocol to ful ll the throughput and delivery requirements of any applications operating on the network. Currently, most of the proposed VANET routing protocols focus on urban or highway environments. This dissertation addresses the need for an adaptive routing...
Show moreA Vehicular Ad-hoc Network (VANET) is a wireless ad-hoc network that provides communications among vehicles with on-board units and between vehicles and nearby roadside units. The success of a VANET relies on the ability of a routing protocol to ful ll the throughput and delivery requirements of any applications operating on the network. Currently, most of the proposed VANET routing protocols focus on urban or highway environments. This dissertation addresses the need for an adaptive routing protocol in VANETs which is able to tolerate low and high-density network tra c with little throughput and delay variation. This dissertation proposes three Geographic Ad-hoc On-Demand Distance Vector (GEOADV) protocols. These three GEOADV routing protocols are designed to address the lack of exibility and adaptability in current VANET routing protocols. The rst protocol, GEOADV, is a hybrid geographic routing protocol. The second protocol, GEOADV-P, enhances GEOADV by introducing predictive features. The third protocol, GEOADV-PF improves optimal route selection by utilizing fuzzy logic in addition to GEOADV-P's predictive capabilities. To prove that GEOADV and GEOADV-P are adaptive their performance is demonstrated by both urban and highway simulations. When compared to existing routing protocols, GEOADV and GEOADV-P lead to less average delay and a higher average delivery ratio in various scenarios. These advantages allow GEOADV- P to outperform other routing protocols in low-density networks and prove itself to be an adaptive routing protocol in a VANET environment. GEOADV-PF is introduced to improve GEOADV and GEOADV-P performance in sparser networks. The introduction of fuzzy systems can help with the intrinsic demands for exibility and adaptability necessary for VANETs. An investigation into the impact adaptive beaconing has on the GEOADV protocol is conducted. GEOADV enhanced with an adaptive beacon method is compared against GEOADV with three xed beacon rates. Our simulation results show that the adaptive beaconing scheme is able to reduce routing overhead, increase the average delivery ratio, and decrease the average delay.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004926, http://purl.flvc.org/fau/fd/FA00004926
- Subject Headings
- Vehicular ad hoc networks (Computer networks)--Design and construction., Routing protocols (Computer network protocols), Wireless sensor networks., Computer algorithms., Mobile computing., Mobile communication systems--Technological innovations., Wireless communication systems--Technological innovations., Intelligent transportation systems--Mathematical models.
- Format
- Document (PDF)
- Title
- Adaptive two-level watermarking for binary document images.
- Creator
- Muharemagic, Edin., Florida Atlantic University, Furht, Borko, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
In our society, large volumes of documents are exchanged on a daily basis. Since documents can easily be scanned, modified and reproduced without any loss in quality, unauthorized use and modification of documents is of major concern. An authentication watermark embedded into a document as an invisible, fragile mark can be used to detect illegal document modification. However, the authentication watermark can only be used to determine whether documents have been tampered with, and additional...
Show moreIn our society, large volumes of documents are exchanged on a daily basis. Since documents can easily be scanned, modified and reproduced without any loss in quality, unauthorized use and modification of documents is of major concern. An authentication watermark embedded into a document as an invisible, fragile mark can be used to detect illegal document modification. However, the authentication watermark can only be used to determine whether documents have been tampered with, and additional protection may be needed to prevent unauthorized use and distribution of those documents. A solution to this problem is a two-level, multipurpose watermark. The first level watermark is an authentication mark used to detect document tampering, while the second level watermark is a robust mark, which identifies the legitimate owner and/or user of specific document. This dissertation introduces a new adaptive two-level multipurpose watermarking scheme suitable for binary document images, such as scanned text, figures, engineering and road maps, architectural drawings, music scores, and handwritten text and sketches. This watermarking scheme uses uniform quantization and overlapped embedding to add two watermarks, one robust and the other fragile, into a binary document image. The two embedded watermarks serve different purposes. The robust watermark carries document owner or document user identification, and the fragile watermark confirms document authenticity and helps detect document tampering. Both watermarks can be extracted without accessing the original document image. The proposed watermarking scheme adaptively selects an image partitioning block size to optimize the embedding capacity, the image permutation key to minimize watermark detection error, and the size of local neighborhood in which modification candidate pixels are scored to minimize visible distortion of watermarked documents. Modification candidate pixels are scored using a novel, objective metric called the Structural Neighborhood Distortion Measure (SNDM). Experimental results confirm that this watermarking scheme, which embeds watermarks by modifying image pixels based on their SNDM scores, creates smaller visible document distortion than watermarking schemes which base watermark embedding on any other published pixel scoring method. Document tampering is detected successfully and the robust watermark can be detected even after document tampering renders the fragile watermark undetectable.
Show less - Date Issued
- 2004
- PURL
- http://purl.flvc.org/fau/fd/FADT12113
- Subject Headings
- Data encryption (Computer science), Computer security, Digital watermarking, Data protection, Image processing--Digital techniques, Watermarks
- Format
- Document (PDF)
- Title
- ADDRESSING HIGHLY IMBALANCED BIG DATA CHALLENGES FOR MEDICARE FRAUD DETECTION.
- Creator
- Johnson, Justin M., Khoshgoftaar, Taghi M., Florida Atlantic University, Department of Computer and Electrical Engineering and Computer Science, College of Engineering and Computer Science
- Abstract/Description
-
Access to affordable healthcare is a nationwide concern that impacts most of the United States population. Medicare is a federal government healthcare program that aims to provide affordable health insurance to the elderly population and individuals with select disabilities. Unfortunately, there is a significant amount of fraud, waste, and abuse within the Medicare system that inevitably raises premiums and costs taxpayers billions of dollars each year. Dedicated task forces investigate the...
Show moreAccess to affordable healthcare is a nationwide concern that impacts most of the United States population. Medicare is a federal government healthcare program that aims to provide affordable health insurance to the elderly population and individuals with select disabilities. Unfortunately, there is a significant amount of fraud, waste, and abuse within the Medicare system that inevitably raises premiums and costs taxpayers billions of dollars each year. Dedicated task forces investigate the most severe fraudulent cases, but with millions of healthcare providers and more than 60 million active Medicare beneficiaries, manual fraud detection efforts are not able to make widespread, meaningful impact. Through the proliferation of electronic health records and continuous breakthroughs in data mining and machine learning, there is a great opportunity to develop and leverage advanced machine learning systems for automating healthcare fraud detection. This dissertation identifies key challenges associated with predictive modeling for large-scale Medicare fraud detection and presents innovative solutions to address these challenges in order to provide state-of-the-art results on multiple real-world Medicare fraud data sets. Our methodology for curating nine distinct Medicare fraud classification data sets is presented with comprehensive details describing data accumulation, data pre-processing, data aggregation techniques, data enrichment strategies, and improved fraud labeling. Data-level and algorithm-level methods for treating severe class imbalance, including a flexible output thresholding method and a cost-sensitive framework, are evaluated using deep neural network and ensemble learners. Novel encoding techniques and representation learning methods for high-dimensional categorical features are proposed to create expressive representations of provider attributes and billing procedure codes.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00014057
- Subject Headings
- Medicare fraud, Big data, Machine learning
- Format
- Document (PDF)
- Title
- Adhesion of calcareous deposits formed on steel surfaces under cathodic polarization.
- Creator
- Luo, Jiunn-Shyong, Florida Atlantic University, Hartt, William H., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
A procedure has been devised to characterize the adhesion of calcareous deposits formed upon steel in association with cathodic polarization in seawater. This involved bending the substrate in-situ and characterization of deposit debonding in terms of visual appearance, changes in the cathodic current density and the net charge transferred in association with film disruption. Specific attention has been focused upon the influence of exposure time, applied potential, flow rate, temperature,...
Show moreA procedure has been devised to characterize the adhesion of calcareous deposits formed upon steel in association with cathodic polarization in seawater. This involved bending the substrate in-situ and characterization of deposit debonding in terms of visual appearance, changes in the cathodic current density and the net charge transferred in association with film disruption. Specific attention has been focused upon the influence of exposure time, applied potential, flow rate, temperature, substrate surface finish and electrolyte type upon deposit adhesion. Presence of a Mg-rich, inner film as well as the impingement of CaCO3 particles enhanced the adhesion of calcareous deposits. Electrostatic forces, Van der Waals attraction, and chemical alteration of precipitates could be important factors contributing to deposit adhesion.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/12271
- Subject Headings
- Sea-water corrosion, Marine steel, Cathodic protection, Adhesives
- Format
- Document (PDF)
- Title
- The adhesive effects in dental restoration.
- Creator
- Vargas, Raul., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The dental field shows proliferation in the market of new adhesives. The purpose of this study is to evaluate the mechanical properties on total restoration, based on the manufacturer's technical specifications, experimental and mechanical test results. The optimal dentist's selection will be when the most appropriate adhesive can be chosen for one specific restoration, avoiding wasted time, material and exposure to marginal infections with a failure restoration. This research was developed...
Show moreThe dental field shows proliferation in the market of new adhesives. The purpose of this study is to evaluate the mechanical properties on total restoration, based on the manufacturer's technical specifications, experimental and mechanical test results. The optimal dentist's selection will be when the most appropriate adhesive can be chosen for one specific restoration, avoiding wasted time, material and exposure to marginal infections with a failure restoration. This research was developed in stages. The first step is the study of the tooth morphological information. Following, there is the structure identification type and the chemical composition of six different pure adhesives. Next, perform the X-R Diffraction, Energy Disperse Spectroscopy (EDS), and Scanning Electron Microscopy (SEM). The final step is to perform the mechanical test, computer simulation, and discuss the results to obtain the best dental adhesive with and the new finding. Result: The samples show an amorphous structure and a chemical composition in the X-R Diffraction, SEM and EDS experiments. The mechanical test shows real mechanical properties under tension and sheer rupture stress. Poisson ratio, strain, and another relationship will be used in the computer simulation test. Results will be reflected in the Discussion and Conclusion. Significance: The first conclusion is that the amorphous structure is present in all six adhesives experiments. In addition, it shows strong possibilities of bonding with another neighbor's molecules. The discussion will be extended to the bonding advantages for this type of structure in the total dental restoration., Findings: First, we found that the time delay of photo polymerization was controlled with the variable water evaporation of the etching treatment. In addition, it was found that the variable size of the wavelength of the curing light obtained better molecular organization and avoided internal stress and bonding defect. Lastly, the chemical composition was a variable that provided the opportunity to predict the type of bond and strength.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fcla/dt/177014
- Subject Headings
- Dental adhesives, Fillings (Dentistry), Polymers in medicine, Dental bonding
- Format
- Document (PDF)
- Title
- Adhesive Joint Analyses Using Ansys CZM Modeling of a Prefabricated Hybrid Concrete-GFRP-CFRP Unit.
- Creator
- Kabaluk, Maksim, Arockiasamy, Madasamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
The present study reviews applications of FRP materials joined by structural adhesives in civil engineering. FE analysis with mix-mode cohesive zone material model (CZM) was used to analyze stresses induced in two structural adhesives joining dissimilar materials (concrete GFRP-CFRP) of the hybrid-composite unit. The predicted failure loads, displacements and deformation by the 3-D non-linear FE analysis in the present study are in good agreement with the experimental results of the hybrid...
Show moreThe present study reviews applications of FRP materials joined by structural adhesives in civil engineering. FE analysis with mix-mode cohesive zone material model (CZM) was used to analyze stresses induced in two structural adhesives joining dissimilar materials (concrete GFRP-CFRP) of the hybrid-composite unit. The predicted failure loads, displacements and deformation by the 3-D non-linear FE analysis in the present study are in good agreement with the experimental results of the hybrid-composite unit reported by Deskovic et al. (1995). The contact analysis revealed a complex 3-D state of stress in the bondlines of both structural adhesives. It is concluded that higher joint strength is expected when a ductile adhesive is used.
Show less - Date Issued
- 2019
- PURL
- http://purl.flvc.org/fau/fd/FA00013222
- Subject Headings
- Adhesive joints, Fiber reinforced polymers, Composites, Concrete
- Format
- Document (PDF)
- Title
- ADVANCED DATA SCIENCE AND PHYSICS-BASED MODELING FOR DYNAMIC SYSTEMS.
- Creator
- Hashemi, Ali, Jang, Jinwoo, Florida Atlantic University, Department of Civil, Environmental and Geomatics Engineering, College of Engineering and Computer Science
- Abstract/Description
-
This dissertation focuses on the development of data-driven and physics-based modeling for two distinct significant structural engineering applications: time-varying response variables estimation and unwanted lateral vibration control. In the first part, I propose a machine learning (ML)-based surrogate modeling to directly predict dynamic responses over an entire mechanical system during operations. Any mechanical system design, as well as structural health monitoring systems, require...
Show moreThis dissertation focuses on the development of data-driven and physics-based modeling for two distinct significant structural engineering applications: time-varying response variables estimation and unwanted lateral vibration control. In the first part, I propose a machine learning (ML)-based surrogate modeling to directly predict dynamic responses over an entire mechanical system during operations. Any mechanical system design, as well as structural health monitoring systems, require transient vibration analysis. However, traditional methods and modeling calculations are time- and resource-consuming. The use of ML approaches is particularly promising in scientific and engineering challenges containing processes that are not completely understood, or where it is computationally infeasible to run numerical or analytical models at desired resolutions in space and time. In this research, an ML-based surrogate for the FEA approach is developed to forecast the time-varying response, i.e., displacement of a two-dimensional truss structure. Various ML regression algorithms including decision trees and deep neural networks are developed to predict movement over a truss structure, and their efficiencies are investigated. ML algorithms have been combined with FEA in preliminary attempts to address issues in static mechanical systems.
Show less - Date Issued
- 2022
- PURL
- http://purl.flvc.org/fau/fd/FA00014048
- Subject Headings
- Dynamics, Data Science, Machine learning
- Format
- Document (PDF)
- Title
- An advanced intelligent network: Description and performance evaluation.
- Creator
- Kadioglu, Ceri., Florida Atlantic University, Ilyas, Mohammad, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
An Advanced Intelligent Network (AIN) is described and its performance is evaluated in this thesis. First, the AIN architecture is presented. This is followed by the description of the operation and the creation of the telephone services in the AIN architecture. Finally, the AIN architecture is evaluated on the performance of the user-network interface and the network elements, and the expandability and cost effectiveness of the architecture. The result of the evaluation shows that the...
Show moreAn Advanced Intelligent Network (AIN) is described and its performance is evaluated in this thesis. First, the AIN architecture is presented. This is followed by the description of the operation and the creation of the telephone services in the AIN architecture. Finally, the AIN architecture is evaluated on the performance of the user-network interface and the network elements, and the expandability and cost effectiveness of the architecture. The result of the evaluation shows that the operation of the telephone services in the AIN architecture are acceptable according to the standards set by Bellcore. Therefore, the AIN architecture meets the objectives set by the telephone operating companies and provides a basis for faster development and deployment of new telephone services in a cost effective manner.
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14688
- Subject Headings
- Telecommunication systems, Telephone systems, Data transmission systems
- Format
- Document (PDF)
- Title
- Advanced methods in sea level rise vulnerability assessment.
- Creator
- Romah, Thomas., College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
Increasing sea levels have the potential to place important portions of the infrastructure we rely on every day at risk. The transportation infrastructure relies on roads, airports, and seaports to move people, services, and goods around in an ever connected global economy. Any disturbances of the transportation modes have reverberating effects throughout the entire economic spectrum. The effects include delays, alterations of routes, and possible changes in the origin and destinations of...
Show moreIncreasing sea levels have the potential to place important portions of the infrastructure we rely on every day at risk. The transportation infrastructure relies on roads, airports, and seaports to move people, services, and goods around in an ever connected global economy. Any disturbances of the transportation modes have reverberating effects throughout the entire economic spectrum. The effects include delays, alterations of routes, and possible changes in the origin and destinations of services and goods. The purpose of this project is to develop an improved methodology for a sea level rise scenario vulnerability assessment model. This new model uses the groundwater elevation as a limiting factor for soil storage capacity in determining previously underestimated areas of vulnerability. The hope is that early identification of vulnerability will allow planners and government officials an opportunity to identify and either remediate or create alternative solutions for vulnerable land areas before high consequence impacts are felt.
Show less - Date Issued
- 2012
- PURL
- http://purl.flvc.org/FAU/3358965
- Subject Headings
- Sea level, Environmental aspects, Coastal zone management, Sea level, Climactic factors, Climate change mitigation, Climatic changes, Risk management
- Format
- Document (PDF)
- Title
- Aerodynamic analysis of a propeller in a turbulent boundary layer flow.
- Creator
- Lachowski, Felipe Ferreira., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
Simulating the exact chaotic turbulent flow field about any geometry is a dilemma between accuracy and computational resources, which has been continuously studied for just over a hundred years. This thesis is a complete walk-through of the entire process utilized to approximate the flow ingested by a Sevik-type rotor based on solutions to the Reynolds Averaged Navier-Stokes equations (RANS). The Multiple Reference Frame fluid model is utilized by the code of ANSYS-FLUENT and results are...
Show moreSimulating the exact chaotic turbulent flow field about any geometry is a dilemma between accuracy and computational resources, which has been continuously studied for just over a hundred years. This thesis is a complete walk-through of the entire process utilized to approximate the flow ingested by a Sevik-type rotor based on solutions to the Reynolds Averaged Navier-Stokes equations (RANS). The Multiple Reference Frame fluid model is utilized by the code of ANSYS-FLUENT and results are validated by experimental wake data. Three open rotor configurations are studied including a uniform inflow and the rotor near a plate with and without a thick boundary layer. Furthermore, observations are made to determine the variation in velocity profiles of the ingested turbulent flow due to varying flow conditions.
Show less - Date Issued
- 2013
- PURL
- http://purl.flvc.org/fcla/dt/3360798
- Subject Headings
- Acoustical engineering, Boundary layer control, Multiphase flow, Mathematical models, Fluid mechanics, Mathematical models, Turbulence, Mathematical models, Computatioinal fluid dynamics
- Format
- Document (PDF)
- Title
- Alleviating class imbalance using data sampling: Examining the effects on classification algorithms.
- Creator
- Napolitano, Amri E., Florida Atlantic University, Khoshgoftaar, Taghi M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Imbalanced class distributions typically cause poor classifier performance on the minority class, which also tends to be the class with the highest cost of mis-classification. Data sampling is a common solution to this problem, and numerous sampling techniques have been proposed to address it. Prior research examining the performance of these techniques has been narrow and limited. This work uses thorough empirical experimentation to compare the performance of seven existing data sampling...
Show moreImbalanced class distributions typically cause poor classifier performance on the minority class, which also tends to be the class with the highest cost of mis-classification. Data sampling is a common solution to this problem, and numerous sampling techniques have been proposed to address it. Prior research examining the performance of these techniques has been narrow and limited. This work uses thorough empirical experimentation to compare the performance of seven existing data sampling techniques using five different classifiers and four different datasets. The work addresses which sampling techniques produce the best performance in the presence of class unbalance, which classifiers are most robust to the problem, as well as which sampling techniques perform better or worse with each classifier. Extensive statistical analysis of these results is provided, in addition to an examination of the qualitative effects of the sampling techniques on the types of predictions made by the C4.5 classifier.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13413
- Subject Headings
- Combinatorial group theory, Data mining, Decision trees, Machine learning
- Format
- Document (PDF)
- Title
- Alopex for handwritten digit recognition: Algorithmic verifications.
- Creator
- Martin, Gregory A., Florida Atlantic University, Shankar, Ravi, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Alopex is a biologically influenced computation paradigm that uses a stochastic procedure to find the global optimum of linear and nonlinear functions. It maps to a hierarchical SIMD (Single-Instruction-Multiple-Data) architecture with simple neuronal processing elements (PE's), therefore the large amount of interconnects in other types of neural networks are not required and more efficient utilization of chip level and board level "real estate" is realized. In this study, verifications were...
Show moreAlopex is a biologically influenced computation paradigm that uses a stochastic procedure to find the global optimum of linear and nonlinear functions. It maps to a hierarchical SIMD (Single-Instruction-Multiple-Data) architecture with simple neuronal processing elements (PE's), therefore the large amount of interconnects in other types of neural networks are not required and more efficient utilization of chip level and board level "real estate" is realized. In this study, verifications were performed on the use of a simplified Alopex algorithm in handwritten digit recognition with the intent that the verified algorithm be digitally implementable. The inputs to the simulated Alopex hardware are a set of 32 features extracted from the input characters. Although the goal of verifying the algorithm was not achieved, a firm direction for future studies has been established and a flexible software model for these future studies is available.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/14842
- Subject Headings
- Algorithms--Data processing, Stochastic processes
- Format
- Document (PDF)
- Title
- An Algorithm for the Automated Interpretation of Cardiac Auscultation.
- Creator
- Lieber, Claude, Erdol, Nurgun, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Cardiac auscultation, an important part of the physical examination, is difficult for many primary care providers. As a result, diagnoses are missed or auscultatory signs misinterpreted. A reliable, automated means of interpreting cardiac auscultation should be of benefit to both the primary care provider and to patients. This paper explores a novel approach to this problem and develops an algorithm that can be expanded to include all the necessary electronics and programming to develop such...
Show moreCardiac auscultation, an important part of the physical examination, is difficult for many primary care providers. As a result, diagnoses are missed or auscultatory signs misinterpreted. A reliable, automated means of interpreting cardiac auscultation should be of benefit to both the primary care provider and to patients. This paper explores a novel approach to this problem and develops an algorithm that can be expanded to include all the necessary electronics and programming to develop such a device. The algorithm is explained and its shortcomings exposed. The potential for further development is also expounded.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004609, http://purl.flvc.org/fau/fd/FA00004609
- Subject Headings
- Phonocardiography., Signal processing., Pattern recognition systems., Imaging systems in medicine., Decision support systems., Medicine--Data processing.
- Format
- Document (PDF)
- Title
- An Analysis of the Surface Pressure Spectra in a Fluid Flow with a Zero-Pressure Gradient Turbulent Boundary Layer.
- Creator
- Balestrieri, Frank, Glegg, Stewart, Florida Atlantic University, Department of Ocean and Mechanical Engineering, College of Engineering and Computer Science
- Abstract/Description
-
The objective of this thesis is to review recently developed empirical and analytical models for the surface pressure and wavenumber spectra for fully developed boundary layers to highlight the effect of assumptions about the turbulence length scales and show how the effects of mean flow Reynolds number has on the spectra shape. The Goody model is used as a reference model to compare the spectra shape as it characterizes the basic physical features of the wall-pressure spectrum under a zero...
Show moreThe objective of this thesis is to review recently developed empirical and analytical models for the surface pressure and wavenumber spectra for fully developed boundary layers to highlight the effect of assumptions about the turbulence length scales and show how the effects of mean flow Reynolds number has on the spectra shape. The Goody model is used as a reference model to compare the spectra shape as it characterizes the basic physical features of the wall-pressure spectrum under a zero-pressure gradient turbulent boundary layer and scales as a function of Reynolds number. The turbulence length scales of the comparison models are modified to observe the effects on the shape of the spectra. A new model is also considered that also scales as a function of Reynolds number and is compared to the Goody model.
Show less - Date Issued
- 2021
- PURL
- http://purl.flvc.org/fau/fd/FA00013816
- Subject Headings
- Turbulent boundary layer, Turbulence
- Format
- Document (PDF)