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- Title
- YACAD: Yet Another Congestion Avoidance Design for ATM-based networks.
- Creator
- Hsu, Sam, Florida Atlantic University, Ilyas, Mohammad, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This dissertation proposes YACAD (Yet Another Congestion Avoidance Design for ATM-based Networks), a congestion prevention model that includes admission control, traffic shaping, and link-by-link flow control for ATM-based networks. Network traffic in this model is composed of real-time traffic and data traffic. As real-time traffic is delay-sensitive and connection-oriented, its call acceptance is based upon the effective bandwidth at all nodes. Effective bandwidth is defined as a vector of...
Show moreThis dissertation proposes YACAD (Yet Another Congestion Avoidance Design for ATM-based Networks), a congestion prevention model that includes admission control, traffic shaping, and link-by-link flow control for ATM-based networks. Network traffic in this model is composed of real-time traffic and data traffic. As real-time traffic is delay-sensitive and connection-oriented, its call acceptance is based upon the effective bandwidth at all nodes. Effective bandwidth is defined as a vector of bandwidth and maximum node delay. As data traffic can be either connection-oriented or connectionless, it is subject to link-by-link flow control based on a criterion known as effective buffer which is defined as a scalar of buffer size. Data traffic is not delay-sensitive but is loss-sensitive. Traffic shaping is imposed on real-time traffic to ensure a smooth inflow of real-time cells. YACAD also allocates a large buffer (fat bucket) to data traffic to accommodate sudden long bursts of data cells. Absence of data cell loss is a major feature of YACAD. Two simulation studies on the performance of the model are conducted. Analyses of the simulation results show that the proposed congestion avoidance model can achieve congestion-free networking and bounded network delays for real-time traffic at high levels of channel utilization. The maximum buffer requirements for loss-free cell delivery for data traffic, and the cell loss probabilities for real-time traffic are also obtained. In addition, results of performance comparisons to other similar models have shown that YACAD outperforms several other leaky-bucket based congestion control methods in terms of cell loss probability for real-time traffic. The simulation source program has also been verified using existing queueing theories, and the Paired-t Confidence Interval method with satisfactory results at 99% confidence level.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/12336
- Subject Headings
- Integrated services digital networks, Broadband communications systems, Packet switching (Data transmission), Computer networks--Management
- Format
- Document (PDF)
- Title
- XYZ: A scalable, partially centralized lookup service for large-scale peer-to-peer systems.
- Creator
- Zhang, Jianying., Florida Atlantic University, Wu, Jie, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Peer-to-Peer (P2P) systems are characterized by direct access between peer computers, rather than through a centralized server. File sharing is the dominant P2P application on the Internet, allowing users to easily contribute, search and obtain content. The objective of this thesis was to design XYZ, a partially centralized, scalable and self-organizing lookup service for wide area P2P systems. The XYZ system is based on distributed hash table (DHT). A unique ID and a color assigned to each...
Show morePeer-to-Peer (P2P) systems are characterized by direct access between peer computers, rather than through a centralized server. File sharing is the dominant P2P application on the Internet, allowing users to easily contribute, search and obtain content. The objective of this thesis was to design XYZ, a partially centralized, scalable and self-organizing lookup service for wide area P2P systems. The XYZ system is based on distributed hash table (DHT). A unique ID and a color assigned to each node and each file. The author uses clustering method to create the system backbone by connecting the cluster heads together and uses color clustering method to create color overlays. Any lookup for a file with a color will only be forwarded in the color overlay with the same color so that the searching space is minimized. Simulations and analysis are also provided in this thesis.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13263
- Subject Headings
- Wireless communication systems, Peer-to-peer architecture (Computer networks), Computational grids (Computer systems)
- Format
- Document (PDF)
- Title
- XYZ Video Compression: An algorithm for real-time compression of motion video based upon the three-dimensional discrete cosine transform.
- Creator
- Westwater, Raymond John., Florida Atlantic University, Furht, Borko, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
XYZ Video Compression denotes a video compression algorithm that operates in three dimensions, without the overhead of motion estimation. The smaller overhead of this algorithm as compared to MPEG and other "standards-based" compression algorithms using motion estimation suggests the suitability of this algorithm to real-time applications. The demonstrated results of compression of standard motion video benchmarks suggest that XYZ Video Compression is not only a faster algorithm, but develops...
Show moreXYZ Video Compression denotes a video compression algorithm that operates in three dimensions, without the overhead of motion estimation. The smaller overhead of this algorithm as compared to MPEG and other "standards-based" compression algorithms using motion estimation suggests the suitability of this algorithm to real-time applications. The demonstrated results of compression of standard motion video benchmarks suggest that XYZ Video Compression is not only a faster algorithm, but develops superior compression ratios as well. The algorithm is based upon the three-dimensional Discrete Cosine Transform (DCT). Pixels are organized as 8 x 8 x 8 cubes by taking 8 x 8 squares out of 8 consecutive frames. A fast three-dimensional transform is applied to each cube, generating 512 DCT coefficients. The energy-packing property of the DCT concentrates the energy in the cube into few coefficients. The DCT coefficients are quantized to maximize the energy concentration at the expense of introduction of a user-determined level of error. A method of adaptive quantization that generates optimal quantizers based upon statistics gathered for the 8 consecutive frames is described. The sensitivity of the human eye to various DCT coefficients is used to modify the quantizers to create a "visually equivalent" cube with still greater energy concentration. Experiments are described that justify choice of Human Visual System factors to be folded into the quantization step. The quantized coefficients are then encoded into a data stream using a method of entropy coding based upon the statistics of the quantized coefficients. The bitstream generated by entropy coding represents the compressed data of the 8 motion video frames, and typically will be compressed at 50:1 at 5% error. The decoding process is the reverse of the encoding process: the bitstream is decoded to generate blocks of quantized DCT coefficients, the DCT coefficients are dequantized, and the Inverse Discrete Cosine Transform is performed on the cube to recover pixel data suitable for display. The elegance of this technique lies in its simplicity, which lends itself to inexpensive implementation of both encoder and decoder. Finally, real-time implementation of the XYZ Compressor/Decompressor is discussed. Experiments are run to determine the effectiveness of the implementation.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12450
- Subject Headings
- Digital video, Data compression (Telecommunication), Image processing--Digital techniques, Coding theory
- Format
- Document (PDF)
- Title
- An XML-based data exchange model.
- Creator
- Sreenivasan, Sridhar., Florida Atlantic University, Hsu, Sam, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Data are the backbone to any organization. In some organizations there are applications that operate on a distributed platform. These applications might often communicate with applications on a different platform, that structures data in a different format. The manner in which data is transferred between such applications can become complex, because there will be many platform dependent applications that need to process the data transferred. Hence a mechanism for exchange of data in a simple,...
Show moreData are the backbone to any organization. In some organizations there are applications that operate on a distributed platform. These applications might often communicate with applications on a different platform, that structures data in a different format. The manner in which data is transferred between such applications can become complex, because there will be many platform dependent applications that need to process the data transferred. Hence a mechanism for exchange of data in a simple, effective manner for such applications is a basic necessity. In this thesis, such a mechanism to deal with data exchange in a platform independent manner is discussed. The proposed model is XML-based, and data between the applications is exchanged in the form of XML documents. XML is text-based and can be processed by any application existing on any platform. The model has an interface that processes the XML documents transferred between the client applications and the underlying database systems. The model is implemented in a System administration application. The application is a Web application that transfers data in the XML format. This is processed by the interface and transferred to the database. Data from the database is retrieved and converted to XML documents by the interface and transferred to the client (Web) applications.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12926
- Subject Headings
- XML (Document markup language)
- Format
- Document (PDF)
- Title
- Workspace evaluation and kinematic calibration of Stewart platform.
- Creator
- Wang, Jian., Florida Atlantic University, Masory, Oren, Roth, Zvi S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Parallel manipulators have their special characteristics in contrast to the traditional serial type of robots. Stewart platform is a typical six degree of freedom fully parallel robot manipulator. The goal of this research is to enhance the accuracy and the restricted workspace of the Stewart platform. The first part of the dissertation discusses the effect of three kinematic constraints: link length limitation, joint angle limitation and link interference, and kinematic parameters on the...
Show moreParallel manipulators have their special characteristics in contrast to the traditional serial type of robots. Stewart platform is a typical six degree of freedom fully parallel robot manipulator. The goal of this research is to enhance the accuracy and the restricted workspace of the Stewart platform. The first part of the dissertation discusses the effect of three kinematic constraints: link length limitation, joint angle limitation and link interference, and kinematic parameters on the workspace of the platform. An algorithm considering the above constraints for the determination of the volume and the envelop of Stewart platform workspace is developed. The workspace volume is used as a criterion to evaluate the effects of the platform dimensions and kinematic constraints on the workspace and the dexterity of the Stewart platform. The analysis and algorithm can be used as a design tool to select dimensions, actuators and joints in order to maximize the workspace. The remaining parts of the dissertation focus on the accuracy enhancement. Manufacturing tolerances, installation errors and link offsets cause deviations with respect to the nominal parameters of the platform. As a result, if nominal parameters are being used, the resulting platform pose will be inaccurate. An accurate kinematic model of Stewart platform which accommodates all manufacturing and installation errors is developed. In order to evaluate the effects of the above factors on the accuracy, algorithms for the forward and inverse kinematics solutions of the accurate model are developed. The effects of different manufacturing tolerances and installation errors on the platform accuracy are investigated based on this model. Simulation results provide insight into the expected accuracy and indicate the major factors contributing to the inaccuracies. In order to enhance the accuracy, there is a need to calibrate the platform, or to determine the actual values of the kinematic parameters (Parameter Identification) and to incorporate these into the inverse kinematic solution (Accuracy Compensation). An error-model based algorithm for the parameter identification is developed. Procedures for the formulation of the identification Jacobian and for accuracy compensation are presented. The algorithms are tested using simulated measurements in which the realistic measurement noise is included. As a result, pose error of the platform are significantly reduced.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/12316
- Subject Headings
- Robots--Control systems, Manipulators (Mechanism), Robotics--Calibration
- Format
- Document (PDF)
- Title
- Wind Feedforward Control of a USV.
- Creator
- Qu, Huajin, von Ellenrieder, Karl, Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
In this research, a wind feedforward (FF) controller has been developed to augment closed loop feedback controllers for the position and heading station keeping control of Unmanned Surface Vehicles (USVs). The performance of the controllers was experimentally tested using a 16 foot USV in an outdoor marine environment. The FF controller was combined with three nonlinear feedback controllers, a Proportional–Derivative (PD) controller, a Backstepping (BS) controller, and a Sliding mode (SM)...
Show moreIn this research, a wind feedforward (FF) controller has been developed to augment closed loop feedback controllers for the position and heading station keeping control of Unmanned Surface Vehicles (USVs). The performance of the controllers was experimentally tested using a 16 foot USV in an outdoor marine environment. The FF controller was combined with three nonlinear feedback controllers, a Proportional–Derivative (PD) controller, a Backstepping (BS) controller, and a Sliding mode (SM) controller, to improve the station-keeping performance of the USV. To address the problem of wind model uncertainties, adaptive wind feedforward (AFF) control schemes are also applied to the FF controller, and implemented together with the BS and SM feedback controllers. The adaptive law is derived using Lyapunov Theory to ensure stability. On-water station keeping tests of each combination of FF and feedback controllers were conducted in the U.S. Intracoastal Waterway in Dania Beach, FL USA. Five runs of each test condition were performed; each run lasted at least 10 minutes. The experiments were conducted in Sea State 1 with an average wind speed of between 1 to 4 meters per second and significant wave heights of less than 0.2 meters. When the performance of the controllers is compared using the Integral of the Absolute Error (IAE) of position criterion, the experimental results indicate that the BS and SM feedback controllers significantly outperform the PD feedback controller (e.g. a 33% and a 44% decreases in the IAE, respectively). It is also found that FF is beneficial for all three feedback controllers and that AFF can further improve the station keeping performance. For example, a BS feedback control combined with AFF control reduces the IAE by 25% when compared with a BS feedback controller combined with a non-adaptive FF controller. Among the eight combinations of controllers tested, SM feedback control combined with AFF control gives the best station keeping performance with an average position and heading error of 0.32 meters and 4.76 degrees, respectively.
Show less - Date Issued
- 2016
- PURL
- http://purl.flvc.org/fau/fd/FA00004623, http://purl.flvc.org/fau/fd/FA00004623
- Subject Headings
- Wind turbines--Control., Adaptive control systems., Adaptive signal processing., Intelligent control systems., Wind-pressure., Intelligent sensors.
- Format
- Document (PDF)
- Title
- Wind effect on super-tall buildings using computational fluid dynamics and structural dynamics.
- Creator
- Assaad, Bilal, Arockiasamy, Madasamy, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
-
Super-tall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 7-10 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of...
Show moreSuper-tall buildings located in high velocity wind regions are highly vulnerable to large lateral loads. Designing for these structures must be done with great engineering judgment by structural professionals. Present methods of evaluating these loads are typically by the use of American Society of Civil Engineers 7-10 standard, field measurements or scaled wind tunnel models. With the rise of high performance computing nodes, an emerging method based on the numerical approach of Computational Fluid Dynamics has created an additional layer of analysis and loading prediction alternative to conventional methods. The present document uses turbulence modeling and numerical algorithms by means of Reynolds-averaged Navier-Stokes and Large Eddy Simulation equations applied to a square prismatic prototype structure in which its dynamic properties have also been investigated. With proper modeling of the atmospheric boundary layer flow, these numerical techniques reveal important aerodynamic properties and enhance flow visualization to structural engineers in a virtual environment.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00004343, http://purl.flvc.org/fau/fd/FA00004343
- Subject Headings
- Boundary layer control, Buildings -- Aerodynamics, Computational fluid dynamics, Structural dynamics -- Data processing, Vortex motion
- Format
- Document (PDF)
- Title
- Weight function approach for stress analysis of the surface crack in a finite plate subjected to nonuniform stress fields.
- Creator
- Jani, Jayant Shivkumar., Florida Atlantic University, Arockiasamy, Madasamy, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
-
The effects of various nonuniform stress fields on the stress intensity factors for the semi-elliptic surface crack (three-dimensional problem) in a finite plate are determined using the weight function approach. The formulation satisfies the linear elastic fracture mechanics criteria and the principle of conservation of energy. Based on the knowledge of stress intensity solutions for the reference load/stress system, the expression for the crack opening displacement function for the surface...
Show moreThe effects of various nonuniform stress fields on the stress intensity factors for the semi-elliptic surface crack (three-dimensional problem) in a finite plate are determined using the weight function approach. The formulation satisfies the linear elastic fracture mechanics criteria and the principle of conservation of energy. Based on the knowledge of stress intensity solutions for the reference load/stress system, the expression for the crack opening displacement function for the surface crack is derived. Using the crack opening displacement function and the reference stress intensity factor, the three-dimensional weight functions and subsequently the stress intensity solutions for the surface crack subjected to nonuniform stress fields are derived. The formulation is then applied to determine the effects of linear, quadratic, cubic, and pure bending stress fields on the stress intensity factor for the surface crack in a finite plate. In the initial stage of the study a two-dimensional problem of an edge-crack emanating from the weld-toe in a T-joint is considered. The effect of parameters such as plate thickness, weld-toe radius, and weld-flank angle on the stress intensity factor for an edge-crack is studied. Finite element analyses of the welded T-joints are performed to study the effects of plate thickness, weld-toe radius and the weld-flank angle on the local stress distribution. The ratio of plate thickness to weld-toe radius ranging from 13.09 to 153.93, and the weld-flank angles of 30, 45, and 60 degrees are considered in the analyses. Based on the results from FEM analyses, a parametric equation for the local stress concentration factor and a polynomial expression for the local stress distribution across the plate thickness are derived using the method of least squares and the polynomial curve-fitting technique.
Show less - Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/12254
- Subject Headings
- Strains and stresses, Plates (Engineering), Fracture mechanics
- Format
- Document (PDF)
- Title
- Web-based wireless sensor network monitoring using smartphones.
- Creator
- Marcus, Anthony M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This thesis consists of the development of a web based wireless sensor network (WSN) monitoring system using smartphones. Typical WSNs consist of networks of wireless sensor nodes dispersed over predetermined areas to acquire, process, and transmit data from these locations. Often it is the case that the WSNs are located in areas too hazardous or inaccessible to humans. We focused on the need for access to this sensed data remotely and present our reference architecture to solve this problem....
Show moreThis thesis consists of the development of a web based wireless sensor network (WSN) monitoring system using smartphones. Typical WSNs consist of networks of wireless sensor nodes dispersed over predetermined areas to acquire, process, and transmit data from these locations. Often it is the case that the WSNs are located in areas too hazardous or inaccessible to humans. We focused on the need for access to this sensed data remotely and present our reference architecture to solve this problem. We developed this architecture for web-based wireless sensor network monitoring and have implemented a prototype that uses Crossbow Mica sensors and Android smartphones for bridging the wireless sensor network with the web services for data storage and retrieval. Our application has the ability to retrieve sensed data directly from a wireless senor network composed of Mica sensors and from a smartphones onboard sensors. The data is displayed on the phone's screen, and then, via Internet connection, they are forwarded to a remote database for manipulation and storage. The attributes sensed and stored by our application are temperature, light, acceleration, GPS position, and geographical direction. Authorized personnel are able to retrieve and observe this data both textually and graphically from any browser with Internet connectivity or through a native Android application. Web-based wireless sensor network architectures using smartphones provides a scalable and expandable solution with applicability in many areas, such as healthcare, environmental monitoring, infrastructure health monitoring, border security, and others.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3171682
- Subject Headings
- Smartphones, Wireless communication systems, Security measures, Wireless communication systems, Technological innovations, Computer networks, Security measures, Ad hoc networks (Computer networks), Security measures
- Format
- Document (PDF)
- Title
- A web-based automated classification system for nursing language based on nursing theory.
- Creator
- Dass, Subhomoy D., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Health care systems consist of various individuals and organizations that aim to meet the health care needs of people and provide a complete and responsive health care solution. One of the important aspects of a health care delivery system is nursing. The use of technology is a vital aspect for delivering an optimum and complete nursing care to individuals; and also for improving the quality and delivery mechanism of nursing care. The model proposed in this thesis for Nursing Knowledge...
Show moreHealth care systems consist of various individuals and organizations that aim to meet the health care needs of people and provide a complete and responsive health care solution. One of the important aspects of a health care delivery system is nursing. The use of technology is a vital aspect for delivering an optimum and complete nursing care to individuals; and also for improving the quality and delivery mechanism of nursing care. The model proposed in this thesis for Nursing Knowledge Management System is a novel knowledge-based decision support system for nurses to capture and manage nursing practice, and further, to monitor nursing care quality, as well as to test aspects of an electronic health record for recording and reporting nursing practice. As a part of a collaborative research of the Christine E. Lynn College of Nursing and the Department of Computer Science, a prototype toolset was developed to capture and manage nursing practice in order to improve the quality of care. This thesis focuses on implementing a web based SOA solution for Automated Classification of Nursing Care Categories, based on the knowledge gained from the prototype for nursing care practice.
Show less - Date Issued
- 2011
- PURL
- http://purl.flvc.org/FAU/3332184
- Subject Headings
- Nursing, Quality control, Outcome asssessment (Medical care), Nursing assessment, Digital techiques, Nursing, Computer-assisted instruction, Nursing informatics
- Format
- Document (PDF)
- Title
- Web services cryptographic patterns.
- Creator
- Hashizume, Keiko., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Data security has been identified as one of the most important concerns where sensitive messages are exchanged over the network. In web service architecture, multiple distributed applications communicate with each other over the network by sending XML messages. How can we protect these sensitive messages? Some web services standards have emerged to tackle this problem. The XML Encryption standard defines the process of encrypting and decrypting all of an XML message, part of an XML message,...
Show moreData security has been identified as one of the most important concerns where sensitive messages are exchanged over the network. In web service architecture, multiple distributed applications communicate with each other over the network by sending XML messages. How can we protect these sensitive messages? Some web services standards have emerged to tackle this problem. The XML Encryption standard defines the process of encrypting and decrypting all of an XML message, part of an XML message, or even an external resource. Like XML Encryption, the XML Signature standard specifies how to digitally sign an entire XML message, part of an XML message, or an external object. WS-Security defines how to embed security tokens, XML encryption, and XML signature into XML documents. It does not define new security mechanisms, but leverages existing security technologies such as encryption and digital signature.
Show less - Date Issued
- 2009
- PURL
- http://purl.flvc.org/FAU/216413
- Subject Headings
- Computer networks, Access control, Data encryption (Computer science), XML (Document markup language), Digital signatures, Computer network architectures
- Format
- Document (PDF)
- Title
- Web log analysis: Experimental studies.
- Creator
- Yang, Zhijian., Florida Atlantic University, Zhong, Shi, Pandya, Abhijit S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
With rapid growth of the World Wide Web, web performance becomes increasingly important for modern businesses, especially for e-commerce. As we all know, web server logs contain potentially useful empirical data to improve web server performance. In this thesis, we discuss some topics related to the analysis of a website's server logs for enhancing server performance, which will benefit some applications in business. Markov chain models are used and allow us to dynamically model page...
Show moreWith rapid growth of the World Wide Web, web performance becomes increasingly important for modern businesses, especially for e-commerce. As we all know, web server logs contain potentially useful empirical data to improve web server performance. In this thesis, we discuss some topics related to the analysis of a website's server logs for enhancing server performance, which will benefit some applications in business. Markov chain models are used and allow us to dynamically model page sequences extracted from server logs. My experimental studies contain three major parts. First, I present a workload characterization study of the website used for my research. Second, Markov chain models are constructed for both page request and page-visiting sequence prediction. Finally, I carefully evaluate the constructed models using an independent test data set, which is from server logs on a different day. The research results demonstrate the effectiveness of Markov chain models for characterizing page-visiting sequences.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13202
- Subject Headings
- Markov processes, Operations research, Business enterprises--Computer networks, Electronic commerce--Data processing
- Format
- Document (PDF)
- Title
- Web accessibility for the hearing impaired.
- Creator
- Pasmore, Simone., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
With the exponential increase of Internet usage and the embedding of multimedia content on the Web, some of the Internet resources remain inaccessible for people with disabilities. Particularly, people who are deaf or Hard of Hearing (HOH) experience inaccessible Web sites due to a lack of Closed Captioning (CC) for multimedia content on the Web, no sign language equivalents for the content on the Web, and an insufficient evaluation framework for determining if a Web page is accessible to the...
Show moreWith the exponential increase of Internet usage and the embedding of multimedia content on the Web, some of the Internet resources remain inaccessible for people with disabilities. Particularly, people who are deaf or Hard of Hearing (HOH) experience inaccessible Web sites due to a lack of Closed Captioning (CC) for multimedia content on the Web, no sign language equivalents for the content on the Web, and an insufficient evaluation framework for determining if a Web page is accessible to the Hearing Impaired community. Several opportunities for accessing content needed to be rectified in order for the Hearing Impaired community to access the full benefits of the information repository on the Internet. The research contributions of this thesis are to resolve some of the Web accessibility problems being faced by the Hearing Impaired community. These objectives are to create an automated CC for the Web for multimedia content, to embed sign language equivalent for content available on the Web, to create a framework to evaluate Web accessibility for the Hearing Impaired community, and to create a social network for the Deaf community. To demonstrate the feasibility of fulfilling the above listed objectives several prototypes were implemented. These prototypes have been used in real life scenarios in order to have an objective evaluation of the proposed framework. Further, the implemented prototypes have had an impact to both the academic community and to the industry.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fcla/dt/177011
- Subject Headings
- Computers and people with disabilities, Interactive multimedia, Hearing impaired, Services for, Communication devices for people with disabilities, User interfaces (Computer systems), Web sites, Design
- Format
- Document (PDF)
- Title
- A wavelet-based detector for underwater communication.
- Creator
- Petljanski, Branko., Florida Atlantic University, Erdol, Nurgun, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The need for reliable underwater communication at Florida Atlantic University is critical in transmitting data to and from Autonomous Underwater Vehicles (AUV) and remote sensors. Since a received signal is corrupted with ambient ocean noise, the nature of such noise is investigated. Furthermore, we establish connection between ambient ocean noise and fractal noise. Since the matched filter is designed under the assumption that noise is white, performance degradation of the matched filter due...
Show moreThe need for reliable underwater communication at Florida Atlantic University is critical in transmitting data to and from Autonomous Underwater Vehicles (AUV) and remote sensors. Since a received signal is corrupted with ambient ocean noise, the nature of such noise is investigated. Furthermore, we establish connection between ambient ocean noise and fractal noise. Since the matched filter is designed under the assumption that noise is white, performance degradation of the matched filter due non-white noise is investigated. We show empirical results that the wavelet transform provides an approximate Karhunen-Loeve expansion for 1/f-type noise. Since whitening can improve only broadband signals, a new method for synchronization signal design in wavelet subspaces with increased energy-to-peak amplitude ratio is presented. The wavelet detector with whitening of fractal noise and detection in wavelet subspace is shown. Results show that the wavelet detector improves detectability, however this is below expectation due to differences between fractal noise and ambient ocean noise.
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12778
- Subject Headings
- Wavelets (Mathematics), Underwater acoustics
- Format
- Document (PDF)
- Title
- Wavelet transform-based digital signal processing.
- Creator
- Basbug, Filiz., Florida Atlantic University, Erdol, Nurgun, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This study deals with applying the wavelet transform to mainly two different areas of signal processing: adaptive signal processing, and signal detection. It starts with background information on the theory of wavelets with an emphasis on the multiresolution representation of signals by the wavelet transform in Chapter 1. Chapter 2 begins with an overview of adaptive filtering in general and extends it to transform domain adaptive filtering. Later in the chapter, a novel adaptive filtering...
Show moreThis study deals with applying the wavelet transform to mainly two different areas of signal processing: adaptive signal processing, and signal detection. It starts with background information on the theory of wavelets with an emphasis on the multiresolution representation of signals by the wavelet transform in Chapter 1. Chapter 2 begins with an overview of adaptive filtering in general and extends it to transform domain adaptive filtering. Later in the chapter, a novel adaptive filtering architecture using the wavelet transform is introduced. The performance of this new structure is evaluated by using the LMS algorithm with variations in step size. As a result of this study, the wavelet transform based adaptive filter is shown to reduce the eigenvalue ratio, or condition number, of the input signal. As a result, the new structure is shown to have faster convergence, implying an improvement in the ability to track rapidly changing signals. Chapter 3 deals with signal detection with the help of the wavelet transform. One scheme studies signal detection by projecting the input signal onto different scales. The relationship between this approach and that of matched filtering is established. Then the effect of different factors on signal detection with the wavelet transform is examined. It is found that the method is robust in the presence of white noise. Also, the wavelets are analyzed as eigenfunctions of a certain random process, and how this gives way to optimal receiver design is shown. It is further demonstrated that the design of an optimum receiver leads to the wavelet transform based adaptive filter structure described in Chapter 2.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/12354
- Subject Headings
- Wavelets (Mathematics), Signal processing--Digital techniques
- Format
- Document (PDF)
- Title
- Wavelet de-noising applied to vibrational envelope analysis methods.
- Creator
- Bertot, Edward Max, Khoshgoftaar, Taghi M., Beaujean, Pierre-Philippe, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
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In the field of machine prognostics, vibration analysis is a proven method for detecting and diagnosing bearing faults in rotating machines. One popular method for interpreting vibration signals is envelope demodulation, which allows a technician to clearly identify an impulsive fault source and its severity. However incipient faults -faults in early stages - are masked by in-band noise, which can make the associated impulses difficult to detect and interpret. In this thesis, Wavelet De...
Show moreIn the field of machine prognostics, vibration analysis is a proven method for detecting and diagnosing bearing faults in rotating machines. One popular method for interpreting vibration signals is envelope demodulation, which allows a technician to clearly identify an impulsive fault source and its severity. However incipient faults -faults in early stages - are masked by in-band noise, which can make the associated impulses difficult to detect and interpret. In this thesis, Wavelet De-Noising (WDN) is implemented after envelope-demodulation to improve accuracy of bearing fault diagnostics. This contrasts the typical approach of de-noising as a preprocessing step. When manually measuring time-domain impulse amplitudes, the algorithm shows varying improvements in Signal-to-Noise Ratio (SNR) relative to background vibrational noise. A frequency-domain measure of SNR agrees with this result.
Show less - Date Issued
- 2014
- PURL
- http://purl.flvc.org/fau/fd/FA00004080, http://purl.flvc.org/fau/fd/FA00004080
- Subject Headings
- Fluid dynamics, Signal processing, Structural dynamics, Wavelet (Mathematics)
- Format
- Document (PDF)
- Title
- Wave Ship Interaction in Transforming Seas.
- Creator
- Gong, Fuxian, Dhanak, Manhar R., Florida Atlantic University, College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
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In near-shore transforming seas, as waves approach the shoreline, wave shoaling and sometimes wave breaking take place due to the decreasing water depth. When a ship advances through the transforming seas, the ship body and waves interact with each other substantially and can lead to unknown motions of the ship hull. The physical process of how the wave transforms in the surf zone and how the vehicle actually behaves when it passes through the transforming seas is a complicated issue that...
Show moreIn near-shore transforming seas, as waves approach the shoreline, wave shoaling and sometimes wave breaking take place due to the decreasing water depth. When a ship advances through the transforming seas, the ship body and waves interact with each other substantially and can lead to unknown motions of the ship hull. The physical process of how the wave transforms in the surf zone and how the vehicle actually behaves when it passes through the transforming seas is a complicated issue that triggers considerable research interest. The goal of my research is to characterize the dynamics of a high-speed surface ship model in transforming seas through a parametric numerical study of the shipwave interactions. In this study, the vehicle of interest is a surface effect ship (SES) and we aim to contribute to developing a methodology for simulating the transforming wave environment, including wave breaking, and its interactions with the SES. The thesis work uses a commercial software package ANSYS Fluent to generate numerical waves and model the interface between water and air using the volume of fluid (VoF) method. A ship motion solver and the dynamic mesh are used to enable the modeled ship to perform three degree-of-freedom (DoF) motion and the near-region of the ship hull to deform as well as re-mesh. Non-conformal meshes with hybrid compositions of different cell types and various grid sizes are used in the simulations for different purposes. Five user-defined functions (UDFs) are dynamically linked with the flow solver to incorporates ship/grid motions, wave damping and output of the numerical results. A series of steps were taken sequentially: 1) validation for ship motions including simulation of a static Wigley hull under steady flows to compare against previous experimental results by other researchers, and the comparison between the static SES model under steady flows and the moving SES model advancing in the calm water; 2) study of the ship with 3 DoF advancing in calm water of both constant depth and varying depth; 3) validation for numerical waves, including predictions of numerically progressive waves in both a regular tank and a tank with a sloped fringing reef to compare with theoretical and experimental results, respectively; 4) investigation of the transforming characteristics of the wave traveling over the sloped fringing reef, which mimics the near-shore wave environment and a study of the dynamics of the SES through transforming waves. We find that the flow solver used in this study reliably models the wave profiles along the ship hull. The comparison between a static SES in a current and a moving SES in calm water at the same Froude number shows that although the velocity fields around the vehicle are significantly different, the wave profiles inside and outside the rigid cushion of the vehicle are similar and the resistance force experienced by the vehicle in the two scenarios agree well over time. We conducted five numerical simulations of the vehicle traveling from shallow water to deep water across the transition zone for different Froude numbers. From the results, we find that as the Froude number increases, the wave resistance force on the vehicle becomes larger in both shallow water and deep water. In addition, the overall mean resistance force experienced by the vehicle over the whole trip increases with the Froude number. Statistical analysis of the wave motions suggests that the energy flux decreases dramatically in the onshore direction as the waves break. The more severe the wave-breaking process, the greater the decrease in energy flux. Both the increase of Froude number and the wave steepness apparently increase the resistance force on the vehicle in the shallow water. This thesis work captures the impact of the transforming characteristics of the waves and closely replicates the behavior of how waves interact with a ship in transforming seas through numerical modeling and simulation.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004916, http://purl.flvc.org/fau/fd/FA00004916
- Subject Headings
- Hydrodynamics--Mathematical models., Fluid dynamics--Mathematical models., Ocean waves--Measurement., Water waves--Measurement., Coastal engineering.
- Format
- Document (PDF)
- Title
- Wave attenuation by rigid and flexible-membrane submerged breakwaters.
- Creator
- Harris, Lee Errol., Florida Atlantic University, Reddy, Dronnadula V., College of Engineering and Computer Science, Department of Ocean and Mechanical Engineering
- Abstract/Description
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This research investigates the use of rigid and flexible-membrane submerged breakwaters for wave energy attenuation. A comprehensive review of breakwater design criteria and previous research on submerged breakwaters is included. Physical model laboratory studies conducted by the author and other researchers are investigated as a means for obtaining formulations for wave transmission coefficients. The mechanisms by which waves are attenuated and break are analyzed using video photography of...
Show moreThis research investigates the use of rigid and flexible-membrane submerged breakwaters for wave energy attenuation. A comprehensive review of breakwater design criteria and previous research on submerged breakwaters is included. Physical model laboratory studies conducted by the author and other researchers are investigated as a means for obtaining formulations for wave transmission coefficients. The mechanisms by which waves are attenuated and break are analyzed using video photography of the wave tank tests. The primary objective of this doctoral research was to determine and compare the wave attenuation of non-conventional rigid and flexible-membrane type submerged breakwaters. Physical model tests were performed using the wave tank facilities at Florida Institute of Technology located in Melbourne, Florida. Six different breakwater cross-sections used were: (1) rectangular, (2) triangular, (3) P.E.P.-$Reef\sp{TM}$, (4) single sand-filled container, (5) three stacked sand-filled containers, and (6) one single water-filled container. The first three breakwater units were rigid (or monolithic), and the last three units are flexible-membrane breakwater units. All six units tested had the same height, length (longshore), and base width (cross-shore), with different cross-sections and shapes, and were composed of different materials. A new classification scheme was developed for breakwaters and artificial reefs, based on water depth, structure height, and wave heights. The wave-structure interaction resulting in the wave breaking on the submerged breakwaters was documented, and the observations were analyzed. Wave transmission coefficients were computed for the six different breakwater models tested, and comparisons between the different models were made. Conclusions regarding the primary factors affecting the effectiveness of rigid and flexible-membrane submerged breakwaters were developed, as were recommendations for further research.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12468
- Subject Headings
- Breakwaters, Water waves
- Format
- Document (PDF)
- Title
- Water Cone Improvement Project.
- Creator
- Foley, Michael, Zitani, Matthew, Scheigner, Kyle, Ortega, Abel, Fisken, Gordon, Su, Tsung-Chow, College of Engineering and Computer Science
- Abstract/Description
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Abstract Object of research is to improve a solar desalination device known as the Water Cone that creates potable water using solar energy. The water cone is a polymeric cone that sits overtop a dish of saline water. The water is evaporated by the sun and condenses back onto the surface of the cone creating fresh water. In an attempt to improve the cone’s water production, two different hydrophobic coatings are applied to the inside of two cones, which allow water droplets to flow at a much...
Show moreAbstract Object of research is to improve a solar desalination device known as the Water Cone that creates potable water using solar energy. The water cone is a polymeric cone that sits overtop a dish of saline water. The water is evaporated by the sun and condenses back onto the surface of the cone creating fresh water. In an attempt to improve the cone’s water production, two different hydrophobic coatings are applied to the inside of two cones, which allow water droplets to flow at a much faster rate, collecting water more quickly. Two water cones are coated separately, and are exposed to sunlight for five days. Water collection for the coated portion of the cone is compared to the uncoated portion of the cone. Results after a first trial show that coating A on the water cone impedes water collection whereas coating B appears to increase water collection.
Show less - Date Issued
- 2015
- PURL
- http://purl.flvc.org/fau/fd/FA00005188
- Subject Headings
- College students --Research --United States.
- Format
- Document (PDF)
- Title
- Water and Soil Salinity Mapping for Southern Everglades using Remote Sensing Techniques and In Situ Observations.
- Creator
- Khadim, Fahad Khan, Su, Hongbo, Florida Atlantic University, College of Engineering and Computer Science, Department of Civil, Environmental and Geomatics Engineering
- Abstract/Description
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Everglades National Park is a hydro-ecologically significant wetland experiencing salinity ingress over the years. This motivated our study to map water salinity using a spatially weighted optimization model (SWOM); and soil salinity using land cover classes and EC thresholds. SWOM was calibrated and validated at 3-km grids with actual salinity for 1998–2001, and yielded acceptable R2 (0.89-0.92) and RMSE (1.73-1.92 ppt). Afterwards, seasonal water salinity mapping for 1996–97, 2004–05, and...
Show moreEverglades National Park is a hydro-ecologically significant wetland experiencing salinity ingress over the years. This motivated our study to map water salinity using a spatially weighted optimization model (SWOM); and soil salinity using land cover classes and EC thresholds. SWOM was calibrated and validated at 3-km grids with actual salinity for 1998–2001, and yielded acceptable R2 (0.89-0.92) and RMSE (1.73-1.92 ppt). Afterwards, seasonal water salinity mapping for 1996–97, 2004–05, and 2016 was carried out. For soil salinity mapping, supervised land cover classification was firstly carried out for 1996, 2000, 2006, 2010 and 2015; with the first four providing average accuracies of 82%-94% against existing NLCD classifications. The land cover classes and EC thresholds helped mapping four soil salinity classes namely, the non saline (EC = 0~2 dS/m), low saline (EC = 2~4 dS/m), moderate saline (EC = 4~8 dS/m) and high saline (EC >8 dS/m) areas.
Show less - Date Issued
- 2017
- PURL
- http://purl.flvc.org/fau/fd/FA00004860, http://purl.flvc.org/fau/fd/FA00004860
- Subject Headings
- Everglades National Park (Fla.)--Environmental conditions., Florida Bay (Fla.)--Environmental conditions., Remote sensing., Multispectral imaging., Environmental monitoring--Remote sensing., Geographic information systems., Soils--Remote sensing., Soil moisture--Measurement., Soil mapping.
- Format
- Document (PDF)