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- Title
- Middle frequency target characteristics.
- Creator
- Castagnet, Sabine., Florida Atlantic University, Cuschieri, Joseph M.
- Abstract/Description
-
The problem of inverse scattering where the scattering structure is unknown, and the physical properties are predicted from the measured echo when the target is insonified with known waveforms, is investigated in this thesis. The scattering structure studied is a submerged, evacuated, spherical elastic shell. The formulation of the echo is carried out using thin shell theory for low and middle frequency range, which basically assumes that shear stresses are negligible. The echo is...
Show moreThe problem of inverse scattering where the scattering structure is unknown, and the physical properties are predicted from the measured echo when the target is insonified with known waveforms, is investigated in this thesis. The scattering structure studied is a submerged, evacuated, spherical elastic shell. The formulation of the echo is carried out using thin shell theory for low and middle frequency range, which basically assumes that shear stresses are negligible. The echo is characterized by the form function in the frequency domain, and the impulse response in the time domain. The results of this thesis show that when using a chirp signal with a 200-250kHz bandwidth as the incident waveform, both the material and size of the shell can be recovered. However, the exact thickness of the shell wall couldn't be extracted.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15423
- Subject Headings
- Elastic plates and shells, Sonar, Frequency response (Dynamics)
- Format
- Document (PDF)
- Title
- Microprocessor design for non-discretionary multilevel security.
- Creator
- Clifton, Daniel B., Florida Atlantic University, Fernandez, Eduardo B.
- Abstract/Description
-
Microprocessor design for data security is examined with regard to both methodology and implementation. The examination begins with seven commercial 32-bit microprocessors which are evaluated against a set of previously published requirements for secure hardware. Then, the methodology and implementation of data secure microprocessor design is presented using an original design. The presentation includes a description of the security policy implemented, a model of secure operation, and a...
Show moreMicroprocessor design for data security is examined with regard to both methodology and implementation. The examination begins with seven commercial 32-bit microprocessors which are evaluated against a set of previously published requirements for secure hardware. Then, the methodology and implementation of data secure microprocessor design is presented using an original design. The presentation includes a description of the security policy implemented, a model of secure operation, and a detailed description of the design. The security-related overhead of the new design is compared to that of two commercial microprocessors. The design is then validated with a formal proof. Finally, the design is shown to protect against several generic attacks.
Show less - Date Issued
- 1988
- PURL
- http://purl.flvc.org/fcla/dt/14443
- Subject Headings
- Microprocessors, Data protection
- Format
- Document (PDF)
- Title
- Modeling multiple abstraction levels in SoC using SystemC.
- Creator
- Jillellamudi, Haritha., Florida Atlantic University, Shankar, Ravi
- Abstract/Description
-
Technological advances are providing us with the capability to integrate more and more functionality into a single chip. This is leading to a new design paradigm, System On a Chip (SoC). SoC design brings with it new challenges and difficulties. Managing these challenges and complexity necessitate modeling of systems at a hierarchy of abstraction levels starting from System Level down to Register Transfer Level. Using a single language across all these levels would ensure that the models are...
Show moreTechnological advances are providing us with the capability to integrate more and more functionality into a single chip. This is leading to a new design paradigm, System On a Chip (SoC). SoC design brings with it new challenges and difficulties. Managing these challenges and complexity necessitate modeling of systems at a hierarchy of abstraction levels starting from System Level down to Register Transfer Level. Using a single language across all these levels would ensure that the models are consistent and error-free. SystemC is one such language that has the infrastructure for specifying the design at System level, Behavioral level and RT levels of abstraction. This thesis showcases the same using two design examples---Simplex Data Protocol and General Purpose Timer (GPT) peripheral. Coding style and level of detailing at different levels are shows. Process of refining from one level to another is illustrated. GPT peripheral module designed in this thesis work can be further reused as a timer library component in system architectures.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13064
- Subject Headings
- Systems on a chip, Abstraction, C++ (Computer program language), System design
- Format
- Document (PDF)
- Title
- Modeling and estimation for the Morpheus AUV dynamics.
- Creator
- Binois, Nicolas., Florida Atlantic University, An, Edgar
- Abstract/Description
-
This thesis describes the determination of linear and nonlinear coefficients for the Morpheus vehicle. Added mass and nonlinear damping terms were obtained by strip-theory. These added mass coefficients were compared to the ones previously computed by boundary-integral method. Open-loop simulations were conducted using both sets of added-mass coefficients along with the damping terms, which were adjusted to fit at-sea data. A previously estimation technique for hydrodynamic coefficients has...
Show moreThis thesis describes the determination of linear and nonlinear coefficients for the Morpheus vehicle. Added mass and nonlinear damping terms were obtained by strip-theory. These added mass coefficients were compared to the ones previously computed by boundary-integral method. Open-loop simulations were conducted using both sets of added-mass coefficients along with the damping terms, which were adjusted to fit at-sea data. A previously estimation technique for hydrodynamic coefficients has been applied to the Morpheus AUV using a Kalman filter. This technique based on linearized equations of motion was tested with linear and nonlinear data generated by simulation. Steering and diving motions were considered resulting in the estimation of different sets of coefficients. Results showed that the estimated values were able to reproduce accurately the vehicle motion in the linear as well as in the nonlinear case.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/12972
- Subject Headings
- Oceanographic submersibles--Mathematical models, Hydrodynamics, Underwater navigation
- Format
- Document (PDF)
- Title
- Modeling and control of a vertically tethered marine platform using an active heave compensation system.
- Creator
- Eide, Linn., Florida Atlantic University, Driscoll, Frederick R.
- Abstract/Description
-
Technology movement toward deeper waters necessitates the control of vertically tethered systems that are used for installing, repairing, and maintaining underwater equipment. This has become an essential ingredient for the future success of the oil industry as the near-shore oil reservoirs are nearly depleted. Increased operation depths cause large oscillations and snap loadings in these longer cables. Research on this topic has been limited, and includes only top feedback control. The...
Show moreTechnology movement toward deeper waters necessitates the control of vertically tethered systems that are used for installing, repairing, and maintaining underwater equipment. This has become an essential ingredient for the future success of the oil industry as the near-shore oil reservoirs are nearly depleted. Increased operation depths cause large oscillations and snap loadings in these longer cables. Research on this topic has been limited, and includes only top feedback control. The controllers developed in this thesis utilize top, bottom and combined top and bottom feedback. They are implemented on a discrete finite element lumped mass cable model. Comparison between PID, LQG and H infinity for all feedback combinations reveal that the Hinfinity controller with both top and bottom feedback has the best performance, while LQG has a more consistent and reliable performance for all feedback cases.
Show less - Date Issued
- 2003
- PURL
- http://purl.flvc.org/fcla/dt/13079
- Subject Headings
- Cables, Submarine--Mathematical models, Offshore structures--Dynamics, Feedback control systems, Ships--Hydrodynamics
- Format
- Document (PDF)
- Title
- Electromagnetic radiation absorption in block models of human bodies.
- Creator
- Jong A Kiem, Raymond Eduard., Florida Atlantic University, Sadiku, Matthew
- Abstract/Description
-
In this thesis an attempt is made to calculate the power absorbed in different parts of a human block model which is located in free space and is exposed to a plane electromagnetic wave. The moment method is applied to solve an integral equation which relates the incident field to the induced electric field in an arbitrarily shaped biological body. To obtain more accurate results, a numerical integration technique developed here has been used. The computations on the induced electric fields...
Show moreIn this thesis an attempt is made to calculate the power absorbed in different parts of a human block model which is located in free space and is exposed to a plane electromagnetic wave. The moment method is applied to solve an integral equation which relates the incident field to the induced electric field in an arbitrarily shaped biological body. To obtain more accurate results, a numerical integration technique developed here has been used. The computations on the induced electric fields compare well with earlier work done in this area. It has been found that there is indeed heating of tissues outside the region of intended treatment in hyperthermia at 80 MHz.
Show less - Date Issued
- 1988
- PURL
- http://purl.flvc.org/fcla/dt/14491
- Subject Headings
- Electromagnetic waves, Human body
- Format
- Document (PDF)
- Title
- Energy-efficient protocols for wireless sensor networks.
- Creator
- Du, Kemei., Florida Atlantic University, Wu, Jie
- Abstract/Description
-
This thesis describes energy-conserving techniques in wireless sensor networks. In wireless sensor networks the sensor nodes gather information and send the information to a base station periodically. Some important messages need be broadcast to all nodes. Due to the limited battery capacity in sensor nodes, energy efficiency is becoming a major challenging problem in these power-constrained networks. Chain-based protocols construct a transmission chain connecting all nodes to save energy...
Show moreThis thesis describes energy-conserving techniques in wireless sensor networks. In wireless sensor networks the sensor nodes gather information and send the information to a base station periodically. Some important messages need be broadcast to all nodes. Due to the limited battery capacity in sensor nodes, energy efficiency is becoming a major challenging problem in these power-constrained networks. Chain-based protocols construct a transmission chain connecting all nodes to save energy dissipation of data transmission. We propose a multiple-chain scheme for all-to-all broadcasting. Furthermore, we develop an energy-efficient chain-construction algorithm which uses a sequence of insertions to minimize the energy consumption along the chain. We propose an energy-based adaptive clustering protocol, in which cluster-head elections depend on not only a probabilistic model but also the remaining energy in each node. This protocol improves the life time of the network by distributing energy usage effectively among the sensor nodes.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12912
- Subject Headings
- Wireless communication systems, Computer network protocols
- Format
- Document (PDF)
- Title
- Energy Efficient Cluster-Based Target Tracking Strategy.
- Creator
- AL-Ghanem, Waleed Khalid, Mahgoub, Imad, Florida Atlantic University
- Abstract/Description
-
This research proposes a cluster-based target tracking strategy for one moving object using wireless sensor networks. The sensor field is organized in 3 hierarchal levels. 1-bit message is sent when a node detects the target. Otherwise the node stays silent. Since in wireless sensor network nodes have limited computational resources, limited storage resources, and limited battery, the code for predicting the target position should be simple, and fast to execute. The algorithm proposed in this...
Show moreThis research proposes a cluster-based target tracking strategy for one moving object using wireless sensor networks. The sensor field is organized in 3 hierarchal levels. 1-bit message is sent when a node detects the target. Otherwise the node stays silent. Since in wireless sensor network nodes have limited computational resources, limited storage resources, and limited battery, the code for predicting the target position should be simple, and fast to execute. The algorithm proposed in this research is simple, fast, and utilizes all available detection data for estimating the location of the target while conserving energy. lbis has the potential of increasing the network life time. A simulation program is developed to study the impact of the field size and density on the overall performance of the strategy. Simulation results show that the strategy saves energy while estimating the location of the target with an acceptable error margin.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00012501
- Subject Headings
- Wireless communication systems--Technological innovations, Sensor networks--Security measures, High performance computing, Adaptive signal processing, Target acquisition, Expert systems (Computer science)
- Format
- Document (PDF)
- Title
- Estimation of information: Theoretics-based delay bounds of MPEG traffic over ATM networks.
- Creator
- Jagannathan, Shuba., Florida Atlantic University, Hsu, Sam, Neelakanta, Perambur S.
- Abstract/Description
-
This thesis addresses a method to deduce the statistical bounds associated with the cell-transfer delay variations (CDVs) encountered by the cells of MPEG traffic, transmitted in the Asynchronous Transfer Mode (ATM) networks. This study focuses on: (1) Estimating CDV arising from multiplexing/switching for both constant bit rate (CBR) and variable bit rate (VBR) traffics via priority allocation based simulations. (2) Developing an information-theoretics based technique to get an insight of...
Show moreThis thesis addresses a method to deduce the statistical bounds associated with the cell-transfer delay variations (CDVs) encountered by the cells of MPEG traffic, transmitted in the Asynchronous Transfer Mode (ATM) networks. This study focuses on: (1) Estimating CDV arising from multiplexing/switching for both constant bit rate (CBR) and variable bit rate (VBR) traffics via priority allocation based simulations. (2) Developing an information-theoretics based technique to get an insight of the combined BER-induced and multiplexing/switching-induced CDVs in ATM networks. Algorithms pertinent to CDV statistics are derived and the lower and upper bounds of the statistics are obtained via simulations in respect of CBR and VBR traffics. Ascertaining these bounds is useful in the cell admission control (CAC) strategies adopted in ATM transmissions. Inferential remarks indicating the effects of traffic parameters (such as bandwidth, burstiness etc.) on the values of the statistical bounds are presented, and scope for further work are presented.
Show less - Date Issued
- 1998
- PURL
- http://purl.flvc.org/fcla/dt/15577
- Subject Headings
- Asynchronous transfer mode, Broadband communication systems, Integrated services digital networks, Information theory
- Format
- Document (PDF)
- Title
- Estimation of Internet transit times using a fast-computing artificial neural network (FC-ANN).
- Creator
- Fasulo, Joseph V., Florida Atlantic University, Neelakanta, Perambur S.
- Abstract/Description
-
The objective of this research is to determine the macroscopic behavior of packet transit-times across the global Internet cloud using an artificial neural network (ANN). Specifically, the problem addressed here refers to using a "fast-convergent" ANN for the purpose indicated. The underlying principle of fast-convergence is that, the data presented in training and prediction modes of the ANN is in the entropy (information-theoretic) domain, and the associated annealing process is "tuned" to...
Show moreThe objective of this research is to determine the macroscopic behavior of packet transit-times across the global Internet cloud using an artificial neural network (ANN). Specifically, the problem addressed here refers to using a "fast-convergent" ANN for the purpose indicated. The underlying principle of fast-convergence is that, the data presented in training and prediction modes of the ANN is in the entropy (information-theoretic) domain, and the associated annealing process is "tuned" to adopt only the useful information content and discard the posentropy part of the data presented. To demonstrate the efficacy of the research pursued, a feedforward ANN structure is developed and the necessary transformations required to convert the input data from the parametric-domain to the entropy-domain (and a corresponding inverse transformation) are followed so as to retrieve the output in parametric-domain. The fast-convergent or fast-computing ANN (FC-ANN) developed is deployed to predict the packet-transit performance across the Internet. (Abstract shortened by UMI.)
Show less - Date Issued
- 2001
- PURL
- http://purl.flvc.org/fcla/dt/12835
- Subject Headings
- Neural networks (Computer science), Information theory, Packet switching (Data transmission), Internet
- Format
- Document (PDF)
- Title
- Elevated temperature and stress ratio effects on the fatigue crack growth of aramid reinforced aluminum laminates.
- Creator
- Gardini, Christopher Alan., Florida Atlantic University, Salivar, Gary C.
- Abstract/Description
-
This investigation concentrated on the fatigue crack growth properties of ARALL laminates. The influence of stress ratio and elevated temperature on fatigue crack growth rates were addressed. It was found that elevated temperature had an effect on the delamination of the fiber/resin lamina from the aluminum sheets resulting in a change in crack growth rate behavior. A stress ratio effect was also present at elevated temperature that could not be explained completely by crack closure concepts.
- Date Issued
- 1990
- PURL
- http://purl.flvc.org/fcla/dt/14666
- Subject Headings
- Aluminum alloys--Fatigue, Aluminum alloys--Cracking, Aluminum alloys--Testing, Laminated metals--Fatigue
- Format
- Document (PDF)
- Title
- Electrochemical impedance spectroscopy to monitor degradation of carbon fiber reinforced polymer composites subjected to simulated ocean environment.
- Creator
- Ahmed, Mohammad Mesbahuddin., Florida Atlantic University, Lipka, Stephen M.
- Abstract/Description
-
This research evaluated the applicability of electrochemical impedance spectroscopy (EIS) as a non-destructive technique to predict and characterize the degradation of carbon fiber reinforced polymer (CFRP) composites exposed to aqueous environments at ambient and 6.2 $\pm$ 0.3 MPa. Changes in EIS data were related to water uptake into the composite material as a function of exposure time. Electrochemically induced damage (both anodic and cathodic) were also evaluated using impedance...
Show moreThis research evaluated the applicability of electrochemical impedance spectroscopy (EIS) as a non-destructive technique to predict and characterize the degradation of carbon fiber reinforced polymer (CFRP) composites exposed to aqueous environments at ambient and 6.2 $\pm$ 0.3 MPa. Changes in EIS data were related to water uptake into the composite material as a function of exposure time. Electrochemically induced damage (both anodic and cathodic) were also evaluated using impedance measurements. Three point flexure tests with concurrent EIS measurements were employed to study the effect of stresses on water uptake and mechanical degradation. Visual observation of the extent of damage (i.e., fiber-matrix debonding) was made using scanning electron microscopy (SEM) and correlated with EIS observation.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/14962
- Subject Headings
- Polymers--Deterioration, Composite materials--Environmental aspects, Carbon fibers, Polymeric composites, Spectrum analysis
- Format
- Document (PDF)
- Title
- Estimation of the scattering function of fading channels for acoustic communications in shallow waters.
- Creator
- Allemand, Vincent., Florida Atlantic University, Beaujean, Pierre-Philippe
- Abstract/Description
-
The measurement of the Scattering function of time-variant fading channels is of strong interest in the field of underwater acoustic communications, as it indicates the limitations of the channel capacity. It also helps reducing the development time of acoustic communication systems and the need for on-site tests using so-called "fading simulators". The Scattering function is interpreted as the expected power received at a given time-delay and frequency shift for a given signal transmitted...
Show moreThe measurement of the Scattering function of time-variant fading channels is of strong interest in the field of underwater acoustic communications, as it indicates the limitations of the channel capacity. It also helps reducing the development time of acoustic communication systems and the need for on-site tests using so-called "fading simulators". The Scattering function is interpreted as the expected power received at a given time-delay and frequency shift for a given signal transmitted through the acoustic channel. It has been estimated using a fourth-moment method developed by Kailath from 18 to 30 kHz, 8-ms broad-band chirps and 20--28 kHz, 28-ms pseudo noise sequences. These signals were transmitted periodically in the shallow coastal waters of South Florida from a static source, and recorded from a 64-channel receiver array located at a distance of 1000 meters. Spatial beamforming has been applied to study the spatial sensitivity of the scattering function.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/13230
- Subject Headings
- Underwater acoustic telemetry, Signal processing--Digital techniques, Underwater acoustics--Mathematical models, Adaptive signal processing
- Format
- Document (PDF)
- Title
- Estimation of motion parameters of a planar body using binocular camera configuration.
- Creator
- Haliyur, Padma., Florida Atlantic University, Sudhakar, Raghavan
- Abstract/Description
-
This thesis is concerned with the estimation of motion parameters of planar-object surfaces viewed with a binocular camera configuration. Possible application of this method includes autonomous guidance of a moving platform (AGVS) via imaging, and segmentation of moving objects by the use of the information concerning the motion and the structure. The brightness constraint equation is obtained by assuming the brightness of a moving patch as almost invariant. This equation is solved for single...
Show moreThis thesis is concerned with the estimation of motion parameters of planar-object surfaces viewed with a binocular camera configuration. Possible application of this method includes autonomous guidance of a moving platform (AGVS) via imaging, and segmentation of moving objects by the use of the information concerning the motion and the structure. The brightness constraint equation is obtained by assuming the brightness of a moving patch as almost invariant. This equation is solved for single camera case as well as binocular camera case by knowing values of the surface normal or by iteratively determining it using the estimates of motion parameters. For this value of the surface normal, rotational and translational motion components are determined over the entire image using a least squares algorithm. This algorithm is tested for simulated images as well as real images pertaining to a single camera as well as binocular camera situations. (Abstract shortened with permission of author.)
Show less - Date Issued
- 1991
- PURL
- http://purl.flvc.org/fcla/dt/14692
- Subject Headings
- Motion, Image processing
- Format
- Document (PDF)
- Title
- APPLICATION OF DATA COMPRESSION TECHNIQUES ON COMPUTER-BASED TEXT AND PROGRAM SOURCE LIBRARIES.
- Creator
- FLOYD, RAYMOND EDWARD., Florida Atlantic University, Marcovitz, Alan B.
- Abstract/Description
-
Data compression in computer based data files has just begun to be used, with the major emphasis placed on character string suppression. Within this paper, character string suppression, Huffman encoding, noun-vector, and dictionary-vector compression methods are reviewed and compared as well as several combinations of these methods. The methods investigated were compared against three typical data library types: 1) program source data files, 2) test case data files, and 3) text data files....
Show moreData compression in computer based data files has just begun to be used, with the major emphasis placed on character string suppression. Within this paper, character string suppression, Huffman encoding, noun-vector, and dictionary-vector compression methods are reviewed and compared as well as several combinations of these methods. The methods investigated were compared against three typical data library types: 1) program source data files, 2) test case data files, and 3) text data files. Compression percentage, speed of compression and decompression, storage requirements, error recovery, and data security comparison of the various methods are also presented.
Show less - Date Issued
- 1977
- PURL
- http://purl.flvc.org/fcla/dt/13852
- Subject Headings
- Data compression (Computer science), Data libraries--Automation
- Format
- Document (PDF)
- Title
- ANALYSIS OF FREE VIBRATIONS OF BEAMS WITH VARYING DEGREES OF UNCONSTRAINED VISCOELASTIC DAMPING LAYER COVERAGE.
- Creator
- DE AGUIAR, JOAO BATISTA., Florida Atlantic University, Dunn, Stanley E.
- Abstract/Description
-
A method of analysis addressing the problem of predicting the performance of beams with viscoelastic damping layer coating of varying degrees of coverage undergoing free vibrations is presented. Results based on this analysis and using mechanical properties of selected materials are generated for five different boundary conditions. The analytical results are verified experimentally for the case of a clamped-free beam. Also the main hypotheses employed in the theoretical approach are verified....
Show moreA method of analysis addressing the problem of predicting the performance of beams with viscoelastic damping layer coating of varying degrees of coverage undergoing free vibrations is presented. Results based on this analysis and using mechanical properties of selected materials are generated for five different boundary conditions. The analytical results are verified experimentally for the case of a clamped-free beam. Also the main hypotheses employed in the theoretical approach are verified. Finally, an analysis of the results leads to a discussion of the dynamic properties of coated beams.
Show less - Date Issued
- 1982
- PURL
- http://purl.flvc.org/fcla/dt/14097
- Subject Headings
- Viscoelasticity, Girders--Vibration
- Format
- Document (PDF)
- Title
- ANALYSIS OF HYDRODYNAMIC INTERACTIONS BETWEEN SHIPS IN CONFINED WATERS.
- Creator
- Ananthakrishnan, Palaniswamy, Florida Atlantic University, Lin, Newman K.
- Abstract/Description
-
The hydrodynamic interactions between ships in confined waters, restricted in width and depth, is analysed using a numerical surface singularity method called the Panel method. Based on potential flow and rigid free surface assumptions, a source distribution is utilized over the boundary surfaces to model the flow. The strength of the source distribution is obtained on satisfying the normal kinematic boundary conditions, i.e. as a solution of an integral equation. Discretization of the...
Show moreThe hydrodynamic interactions between ships in confined waters, restricted in width and depth, is analysed using a numerical surface singularity method called the Panel method. Based on potential flow and rigid free surface assumptions, a source distribution is utilized over the boundary surfaces to model the flow. The strength of the source distribution is obtained on satisfying the normal kinematic boundary conditions, i.e. as a solution of an integral equation. Discretization of the boundary surfaces yields a system of linear algebraic equations corresponding to the boundary integral equation, which then is solved numerically. From the singularity distribution, the velocity components, pressure coefficients and finally the interaction loads are calculated.
Show less - Date Issued
- 1985
- PURL
- http://purl.flvc.org/fcla/dt/14272
- Subject Headings
- Ships--Hydrodynamics
- Format
- Document (PDF)
- Title
- Comparison of embedded security versus separated security in an application.
- Creator
- Oviedo, Carlos., Florida Atlantic University, VanHilst, Michael
- Abstract/Description
-
This work discusses and compares two different approaches that design and implement a requirement for security in an application. The construction process followed for the security features determines how easily further changes can be accommodated, after the application has been built. How the problem is decomposed into modules, and when, determines if a solution or parts from the solution will be reusable without modification in the same application after changes have been made to address a...
Show moreThis work discusses and compares two different approaches that design and implement a requirement for security in an application. The construction process followed for the security features determines how easily further changes can be accommodated, after the application has been built. How the problem is decomposed into modules, and when, determines if a solution or parts from the solution will be reusable without modification in the same application after changes have been made to address a new or altered requirement. Two construction perspectives are analyzed. In the first perspective, security features are embedded within the application design. In the second approach, the security design is separated from the rest of the application. For this latter implementation, an aspect oriented approach is used. The analysis performed shows that how the problem is decomposed leads to different designs, which present different levels of challenge for the application's future evolution. If a more adaptable solution can be designed and implemented, then the application will be more flexible to accommodate new changes and, as a consequence, be more reusable.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13324
- Subject Headings
- Data encryption (Computer science), Computer security, Embedded computer systems
- Format
- Document (PDF)
- Title
- Crack propagation in concrete structural members strengthened with bonded fiber reinforced polymer plastic (FRP) laminates.
- Creator
- Gervois, Gonzague., Florida Atlantic University, Reddy, Dronnadula V.
- Abstract/Description
-
This thesis presents an experimental and analytical investigation of concrete structural members strengthened with externally bonded composite laminates with varying configurations. Parameters, such as size, type of laminate, debond, etc., are evaluated from the viewpoint of stress patterns and their influence on interfacial debonds. Stress patterns in the structure and stress intensity factors around crack tips are determined using a finite element model developed for this purpose. The study...
Show moreThis thesis presents an experimental and analytical investigation of concrete structural members strengthened with externally bonded composite laminates with varying configurations. Parameters, such as size, type of laminate, debond, etc., are evaluated from the viewpoint of stress patterns and their influence on interfacial debonds. Stress patterns in the structure and stress intensity factors around crack tips are determined using a finite element model developed for this purpose. The study also includes a precise description of cracking and the failure function of each parameter investigated. Besides the development of an innovative finite element program, which enables the study of interfacial cracks in structures with highly nonlinear behavior and multiple irregular cracking patterns, the significant contributions include the effect of laminate geometry, the inefficiency of laminate prestressing, the negative effect of end debond, and the insignificant effect of midspan debond on the cracking and the strength of a laminated concrete structural member.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15498
- Subject Headings
- Fiber reinforced plastics, Laminated materials, Concrete--Cracking
- Format
- Document (PDF)
- Title
- Comparative evaluation of the performance of concrete wall panels, with and without fiber reinforcement.
- Creator
- Germain, Gerson S., Florida Atlantic University, Reddy, Dronnadula V.
- Abstract/Description
-
This investigation addresses the evaluation of the increase in structural integrity of concrete wall panels by the addition of polypropylene fibers. The test methodology used was the evaluation of flexural (simply-supported and cantilever), shear (in-plane and punching), and impact behavior. The concrete panels comprised sets with (i) regular reinforcement (ACI code based), (ii) Reinforced concrete panels: 0.2% fibers with minimum ACI reinforcement, FRC 2, (iii) 0.3% fibers without...
Show moreThis investigation addresses the evaluation of the increase in structural integrity of concrete wall panels by the addition of polypropylene fibers. The test methodology used was the evaluation of flexural (simply-supported and cantilever), shear (in-plane and punching), and impact behavior. The concrete panels comprised sets with (i) regular reinforcement (ACI code based), (ii) Reinforced concrete panels: 0.2% fibers with minimum ACI reinforcement, FRC 2, (iii) 0.3% fibers without reinforcement, FRC 3, and (iv) plain beams without reinforcement. The instrumentation consisted of deflection and electrical strain gages, a slope indicator for slope testing, and an oscilloscope with a camera attachment for monitoring load and energy traces in impact testing. The normalized (adjusted for concrete strength variations) ultimate load and energy values were compared. The findings indicated enhancement of ductility and shear strength for the fiber reinforced specimens, which are very desirable for sudden and impact loading conditions associated with hurricane-type loading.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/12678
- Subject Headings
- Concrete walls--Design and construction, Reinforced concrete, Fiber
- Format
- Document (PDF)