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- Title
- GENERIC NETWORK EXECUTIVE.
- Creator
- SARMIENTO, JESUS LEOPOLDO., Florida Atlantic University, Fernandez, Eduardo B., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
A Generic Network Executive (GNE) package is presented in this thesis. It encompasses the strategy and methodology to follow when implementing data communication software. GNE was designed for portability and high utilization of available resources (efficiency). It does not impose implementation constraints because it does not include features specific to any system (hardware or operating system}. It uses a highly concurrent process model with a pipelined structure . It is not protocol...
Show moreA Generic Network Executive (GNE) package is presented in this thesis. It encompasses the strategy and methodology to follow when implementing data communication software. GNE was designed for portability and high utilization of available resources (efficiency). It does not impose implementation constraints because it does not include features specific to any system (hardware or operating system}. It uses a highly concurrent process model with a pipelined structure . It is not protocol dependent, rather it is meant to be used to implement low level services for higher level communic ation protocols. It is intended to provide interprocess communication in distributed systems by coupling application programs with a general purpose packet delivery system, i.e., a datagram service.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14321
- Subject Headings
- Computer networks, Data transmission systems
- Format
- Document (PDF)
- Title
- Fuzzy identification of processes on finite training sets with known features.
- Creator
- Diaz-Robainas, Regino R., Florida Atlantic University, Huang, Ming Z., Zilouchian, Ali, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
A methodology is presented to construct an approximate fuzzy-mapping algorithm that maps multiple inputs to single outputs given a finite training set of argument vectors functionally linked to corresponding scalar outputs. Its scope is limited to problems where the features are known in advance, or equivalently, where the expected functional representation is known to depend exclusively on the known selected variables. Programming and simulations to implement the methodology make use of...
Show moreA methodology is presented to construct an approximate fuzzy-mapping algorithm that maps multiple inputs to single outputs given a finite training set of argument vectors functionally linked to corresponding scalar outputs. Its scope is limited to problems where the features are known in advance, or equivalently, where the expected functional representation is known to depend exclusively on the known selected variables. Programming and simulations to implement the methodology make use of Matlab Fuzzy and Neural toolboxes and a PC application of Prolog, and applications range from approximate representations of the direct kinematics of parallel manipulators to fuzzy controllers.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12487
- Subject Headings
- Fuzzy algorithms, Set theory, Logic, Symbolic and mathematical, Finite groups, Representations of groups
- Format
- Document (PDF)
- Title
- Fuzzy vault fingerprint cryptography: Experimental and simulation studies.
- Creator
- Kotlarchyk, Alex J., Florida Atlantic University, Pandya, Abhijit S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The fuzzy vault scheme introduced by Juels and Sudan [Jue02] was implemented in a fingerprint cryptography system using COTS software. This system proved to be unsuccessful. Failure analysis led to a series of simulations to investigate the parameters and system thresholds necessary for such a system to perform adequately and as guidance for constructing similar systems in the future. First, a discussion of the role of biometrics in data security and cryptography is presented, followed by a...
Show moreThe fuzzy vault scheme introduced by Juels and Sudan [Jue02] was implemented in a fingerprint cryptography system using COTS software. This system proved to be unsuccessful. Failure analysis led to a series of simulations to investigate the parameters and system thresholds necessary for such a system to perform adequately and as guidance for constructing similar systems in the future. First, a discussion of the role of biometrics in data security and cryptography is presented, followed by a review of the key developments leading to the development of the fuzzy vault scheme. The relevant mathematics and algorithms are briefly explained. This is followed by a detailed description of the implementation and simulation of the fuzzy vault scheme. Finally, conclusions drawn from analysis of the results of this research are presented.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13360
- Subject Headings
- Computer networks--Security measures, Computer security, Data encryption (Computer science)
- Format
- Document (PDF)
- Title
- Generating formal models from UML class diagrams.
- Creator
- Shroff, Malcolm Keki., Florida Atlantic University, France, Robert B., Larrondo-Petrie, Maria M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The rich structuring mechanisms, and abstract modeling constructs available in most graphical object-oriented modeling methods (OOMs) facilitate the creation of abstract, visually-appealing, highly-structured graphical models. On the other hand, lack of formal semantics for the modeling notation can severely limit the utility of OOMs. Formal specification techniques (FSTs) support the creation of precise and analyzable specifications, but they can be tedious to create and difficult to read,...
Show moreThe rich structuring mechanisms, and abstract modeling constructs available in most graphical object-oriented modeling methods (OOMs) facilitate the creation of abstract, visually-appealing, highly-structured graphical models. On the other hand, lack of formal semantics for the modeling notation can severely limit the utility of OOMs. Formal specification techniques (FSTs) support the creation of precise and analyzable specifications, but they can be tedious to create and difficult to read, especially by system developers not trained in formal methods. The complementary strengths of OOMs and FSTs suggest that their integration can result in techniques that can be used to create precise and analyzable models. This thesis describes a technique for integrating analysis level UML (Unified Modeling Language) Class Diagrams with the formal notation Object-Z.
Show less - Date Issued
- 1997
- PURL
- http://purl.flvc.org/fcla/dt/15514
- Subject Headings
- UML (Computer science), Object-oriented methods (Computer science)
- Format
- Document (PDF)
- Title
- Low latency and energy efficient MAC protocols for wireless sensor networks.
- Creator
- Abu-El Humos, Ali M., Florida Atlantic University, Alhalabi, Bassem A., Cardei, Mihaela, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Energy consumption is a critical design issue in Wireless Sensor Networks (WSNs), since sensor nodes are battery operated, and replacing or recharging the battery is usually infeasible. Energy efficient solutions are sought at all network levels, especially at the medium access level. The IEEE 802.11 MAC protocol is optimized for Ad hoc Wireless Networks, but cannot be adopted for WSNs because it has the idle listening problem, which is a major source of energy waste. Several Medium Access...
Show moreEnergy consumption is a critical design issue in Wireless Sensor Networks (WSNs), since sensor nodes are battery operated, and replacing or recharging the battery is usually infeasible. Energy efficient solutions are sought at all network levels, especially at the medium access level. The IEEE 802.11 MAC protocol is optimized for Ad hoc Wireless Networks, but cannot be adopted for WSNs because it has the idle listening problem, which is a major source of energy waste. Several Medium Access Control (MAC) protocols have been proposed for WSNs to save the transceiver energy by introducing periodic listen/sleep cycles, and thus overcome the idle listing problem. The periodic listen sleep cycles, however, will increase the network latency and require extra overhead to establish and maintain synchronization among nodes in the network. This dissertation introduces a new MAC protocol for WSNs based on the SMAC protocol to improve its latency performance without compromising its energy consumption. The original SMAC provides an efficient solution for the energy consumption problem due to idle listening, but it increases latency especially in low duty cycle applications. TMAC was proposed to further reduce the energy consumption in SMAC and introduced the Forward Request-To-Send (FRTS) packet to solve the early sleep problem observed in TMAC. Later, Adaptive SMAC was proposed to reduce the latency problem in SMAC by at least 50% at light traffic load. Our new protocol, FASMAC, combines the advantages of both adaptive listening and the usage of FRTS packet in TMAC to further reduce the latency of SMAC. In FASMAC, a packet can travel at least three hops away from its source node within one time cycle. This results in at least 67% reduction in latency at light traffic when compared with the original SMAC. We also propose an energy model for performance evaluation of WSNs protocols using the network simulator NS2. The current energy model of NS2 was designed to handle Ad hoc Wireless Networks where the low power consumption sleep mode was not an issue. However, this is not the case in WSNs. We show that NS2 energy model is not suitable to evaluate the performance of WSNs protocols because it does not account for the low power sleep mode. This dissertation proposes a solution to this deficiency and provides simulation results that match real experimental results performed on the actual sensor motes.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/12149
- Subject Headings
- Wireless communication systems, Sensor networks, Power resources--Efficiency
- Format
- Document (PDF)
- Title
- A MAINTENANCE PROCESSOR FOR THE IBM SERIES/1 (SERVICE, DIAGNOSTIC).
- Creator
- MURPHY, DAVID JAMES, III., Florida Atlantic University, Fernandez, Eduardo B., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
As the Series/1 is used in more complex, unattended, or critical applications, users of the product cannot tolerate the mean time to repair of the current field service support. Long waits for technicians to arrive, troubleshoot the system, and repair or replace parts are no longer acceptable. This thesis presents the system architecture and functional capabilities of a maintenance processor for the Series/1. The maintenance processor designed herein can be used as the focal point of most...
Show moreAs the Series/1 is used in more complex, unattended, or critical applications, users of the product cannot tolerate the mean time to repair of the current field service support. Long waits for technicians to arrive, troubleshoot the system, and repair or replace parts are no longer acceptable. This thesis presents the system architecture and functional capabilities of a maintenance processor for the Series/1. The maintenance processor designed herein can be used as the focal point of most system support activities. This approach has been used in mainframe systems for some time but has not, in the past, been deemed feasible for smaller systerns such as the Series/1. This effort demonstrates the feasibility of a maintenance processor in such systems, resulting in a simplification of hardware and software while providing a significant improvement in total system reliability, availability, and serviceability.
Show less - Date Issued
- 1985
- PURL
- http://purl.flvc.org/fcla/dt/14248
- Subject Headings
- IBM Series/1 (Computer), Software maintenance
- Format
- Document (PDF)
- Title
- Learning in connectionist networks using the Alopex algorithm.
- Creator
- Venugopal, Kootala Pattath., Florida Atlantic University, Pandya, Abhijit S., Sudhakar, Raghavan, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The Alopex algorithm is presented as a universal learning algorithm for connectionist models. It is shown that the Alopex procedure could be used efficiently as a supervised learning algorithm for such models. The algorithm is demonstrated successfully on a variety of network architectures. Such architectures include multilayer perceptrons, time-delay models, asymmetric, fully recurrent networks and memory neuron networks. The learning performance as well as the generation capability of the...
Show moreThe Alopex algorithm is presented as a universal learning algorithm for connectionist models. It is shown that the Alopex procedure could be used efficiently as a supervised learning algorithm for such models. The algorithm is demonstrated successfully on a variety of network architectures. Such architectures include multilayer perceptrons, time-delay models, asymmetric, fully recurrent networks and memory neuron networks. The learning performance as well as the generation capability of the Alopex algorithm are compared with those of the backpropagation procedure, concerning a number of benchmark problems, and it is shown that the Alopex has specific advantages over the backpropagation. Two new architectures (gain layer schemes) are proposed for the on-line, direct adaptive control of dynamical systems using neural networks. The proposed schemes are shown to provide better dynamic response and tracking characteristics, than the other existing direct control schemes. A velocity reference scheme is introduced to improve the dynamic response of on-line learning controllers. The proposed learning algorithm and architectures are studied on three practical problems; (i) Classification of handwritten digits using Fourier Descriptors; (ii) Recognition of underwater targets from sonar returns, considering temporal dependencies of consecutive returns and (iii) On-line learning control of autonomous underwater vehicles, starting with random initial conditions. Detailed studies are conducted on the learning control applications. Effect of the network learning rate on the tracking performance and dynamic response of the system are investigated. Also, the ability of the neural network controllers to adapt to slow and sudden varying parameter disturbances and measurement noise is studied in detail.
Show less - Date Issued
- 1993
- PURL
- http://purl.flvc.org/fcla/dt/12325
- Subject Headings
- Computer algorithms, Computer networks, Neural networks (Computer science), Machine learning
- Format
- Document (PDF)
- Title
- MEMORY LOADER SYSTEM FOR AN AUTOMATIC TEST SET.
- Creator
- MASKASKY, ROBERT JAY., Florida Atlantic University, Fernandez, Eduardo B., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The STS 6003500 computerized automatic teat set is used to support the AH/ASN-91 computer used in the Navy's A-7 attack aircraft. The teat set currently loads teat programs from an IBM 2415 Magnetic tape unit which is obsolete. A new memory loader system is needed to load test programs into the teat set. Using modern Personal Computer technology, this can be accomplished economically with a personal computer and a hard disk drive. The personal computer will act as an intelligent interface...
Show moreThe STS 6003500 computerized automatic teat set is used to support the AH/ASN-91 computer used in the Navy's A-7 attack aircraft. The teat set currently loads teat programs from an IBM 2415 Magnetic tape unit which is obsolete. A new memory loader system is needed to load test programs into the teat set. Using modern Personal Computer technology, this can be accomplished economically with a personal computer and a hard disk drive. The personal computer will act as an intelligent interface between the bard disk drive and the teat set. The personal computer can also provide numerous functions for the convenience of the teat set operator. The flexibility of the personal computer allows easy adaptation to other computerized automatic test sets which are faced with similar problems.
Show less - Date Issued
- 1986
- PURL
- http://purl.flvc.org/fcla/dt/14345
- Subject Headings
- Computer interfaces, Microcomputers
- Format
- Document (PDF)
- Title
- Measurement of brain activity using an ultrasonic measure of localized blood flow.
- Creator
- Dinev, Petko Dimitrov., Florida Atlantic University, Glenn, William E., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This dissertation presents a new type of two-dimensional, real time, color ultrasonic scanner able to measure and display brain metabolism by monitoring amplitudes of localized changes of intracranial interfaces. A real time image is obtained with a flexible array of transducers which eliminates the strong reflection from the skull due to a shape mismatch, and reduces the topological mislocations in the image. The image is generated by a superposition of a gray scale image representing static...
Show moreThis dissertation presents a new type of two-dimensional, real time, color ultrasonic scanner able to measure and display brain metabolism by monitoring amplitudes of localized changes of intracranial interfaces. A real time image is obtained with a flexible array of transducers which eliminates the strong reflection from the skull due to a shape mismatch, and reduces the topological mislocations in the image. The image is generated by a superposition of a gray scale image representing static structures, and a color coded pattern representing motion information. The new technique of motion detection based on image subtraction features high accuracy and gives the scanner the unique capability to detect multidirectional motion of the intracranial interfaces, and to display the amplitude of the motion in real time. A series of experiments performed with the scanner demonstrates outstanding agreement between theoretical design and hardware performance. The scanner has been measured to have a lateral resolution of 4 mm, a temporal resolution of 30 fr/s, a motion detection resolution of 5 $\mu$m, a time gain compensation of 40 dB, and a signal/noise ratio of more than 40 dB. Successful tests, performed on a live human brain, show a well defined echo pattern arising from intracranial structures within the brain, and a strong correlation between the detected surface pulsations and heart beat has been observed. Monitoring the image synchronously with the heart beat and the external stimulus presence gives clinicians the unique opportunity of visualization of detailed cross-sectional anatomy of portions of the human brain, permitting direct observation, mapping the structure and function in a normal human brain, and studying the pathophysiology of mental illness by demonstrating structural metabolic, and neurochemical abnormalities. Additional experiments, performed on other parts of the human body, demonstrated clearly the advanced features of the scanner and its successful application to other areas of medicine beyond neurology. Furthermore, this new real time, two-dimensional brain scanner will be suitable for remote diagnosis and consultation, and long-distance delivery of quality health care via teleconferencing and telecommunication equipment. The modular design of the scanner allows blocks, such as multidirectional motion detection, and the flexible transducer array to be used as stand alone units or to be built into already existing ultrasonic equipment such as sonars, motion sensors, nondestructive testing of materials, etc.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12485
- Subject Headings
- Diagnosis, Ultrasonic, Blood-vessels--Ultrasonic imaging, Ultrasonics in medicine
- Format
- Document (PDF)
- Title
- Maximum entropy-based optimization of artificial neural networks: An application to ATM telecommunication parameter predictions.
- Creator
- Sundaram, Karthik., Florida Atlantic University, De Groff, Dolores F., Neelakanta, Perambur S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This thesis addresses studies on cost-functions developed on the basis of maximum entropy principle, for applications in artificial neural network (ANN) optimization endeavors. The maximization of entropy refers to maximizing Shannon information pertinent to the difference in the output and the teacher value of an ANN. Apart from the Shannon format of the negative entropy formulation a set of Csiszar family functions are also considered. The error-measures obtained, via these maximum entropy...
Show moreThis thesis addresses studies on cost-functions developed on the basis of maximum entropy principle, for applications in artificial neural network (ANN) optimization endeavors. The maximization of entropy refers to maximizing Shannon information pertinent to the difference in the output and the teacher value of an ANN. Apart from the Shannon format of the negative entropy formulation a set of Csiszar family functions are also considered. The error-measures obtained, via these maximum entropy formulations are adopted as cost-functions in the training and prediction schedules of a test perceptron. A comparative study is done on the performance of these cost-functions in facilitating the test network towards optimization so as to predict a standard teacher function sin (.). The study is also extended to predict a parameter (such as cell delay variation) in a practical ATM telecommunication system. Concluding remarks and scope for an extended study are also indicated.
Show less - Date Issued
- 1999
- PURL
- http://purl.flvc.org/fcla/dt/15660
- Subject Headings
- Neural network (Computer science), Asynchronous transfer mode
- Format
- Document (PDF)
- Title
- Mathematical modeling techniques applied to EMI prediction in printed circuit boards.
- Creator
- Perez-Rodriguez, Reinaldo J., Florida Atlantic University, Ungvichian, Vichate, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
A formulation with its computer code based on the method of moments for thin wire structures is used for modeling the radiated fields emanated from a multilayer PCB. The moment method modeling technique proves to be a valuable tool for EMI prediction in a PCB at radio frequencies as well as useful design technique for obtaining the PCB layout which produces the least amount of radiation. A new modeling of the current distribution which includes the effect of microstrip open-end and bend...
Show moreA formulation with its computer code based on the method of moments for thin wire structures is used for modeling the radiated fields emanated from a multilayer PCB. The moment method modeling technique proves to be a valuable tool for EMI prediction in a PCB at radio frequencies as well as useful design technique for obtaining the PCB layout which produces the least amount of radiation. A new modeling of the current distribution which includes the effect of microstrip open-end and bend discontinuities is used. The new modeling increases the accuracy of the prediction model for calculating the radiated EMI. The applicability of the moment method technique for studying the current distribution of wide microstrip is shown by modeling the existence of longitudinal and transverse currents at bend discontinuities.
Show less - Date Issued
- 1989
- PURL
- http://purl.flvc.org/fcla/dt/11931
- Subject Headings
- Printed circuits--Design and construction, Electromagnetic interference
- Format
- Document (PDF)
- Title
- Information theory and software measurement.
- Creator
- Allen, Edward B., Florida Atlantic University, Khoshgoftaar, Taghi M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Development of reliable, high quality, software requires study and understanding at each step of the development process. A basic assumption in the field of software measurement is that metrics of internal software attributes somehow relate to the intrinsic difficulty in understanding a program. Measuring the information content of a program attempts to indirectly quantify the comprehension task. Information theory based software metrics are attractive because they quantify the amount of...
Show moreDevelopment of reliable, high quality, software requires study and understanding at each step of the development process. A basic assumption in the field of software measurement is that metrics of internal software attributes somehow relate to the intrinsic difficulty in understanding a program. Measuring the information content of a program attempts to indirectly quantify the comprehension task. Information theory based software metrics are attractive because they quantify the amount of information in a well defined framework. However, most information theory based metrics have been proposed with little reference to measurement theory fundamentals, and empirical validation of predictive quality models has been lacking. This dissertation proves that representative information theory based software metrics can be "meaningful" components of software quality models in the context of measurement theory. To this end, members of a major class of metrics are shown to be regular representations of Minimum Description Length or Variety of software attributes, and are interval scale. An empirical validation case study is presented that predicted faults in modules based on Operator Information. This metric is closely related to Harrison's Average Information Content Classification, which is the entropy of the operators. New general methods for calculating synthetic complexity at the system level and module level are presented, quantifying the joint information of an arbitrary set of primitive software measures. Since all kinds of information are not equally relevant to software quality factors, components of synthetic module complexity are also defined. Empirical case studies illustrate the potential usefulness of the proposed synthetic metrics. A metrics data base is often the key to a successful ongoing software metrics program. The contribution of any proposed metric is defined in terms of measured variation using information theory, irrespective of the metric's usefulness in quality models. This is of interest when full validation is not practical. Case studies illustrate the method.
Show less - Date Issued
- 1995
- PURL
- http://purl.flvc.org/fcla/dt/12412
- Subject Headings
- Software engineering, Computer software--Quality control, Information theory
- Format
- Document (PDF)
- Title
- Information-theoretics based analysis of hard handoffs in mobile communications.
- Creator
- Bendett, Raymond Morris., Florida Atlantic University, Neelakanta, Perambur S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
The research proposed and elaborated in this dissertation is concerned with the development of new decision algorithms for hard handoff strategies in mobile communication systems. Specifically, the research tasks envisaged include the following: (1) Use of information-theoretics based statistical distance measures as a metric for hard handoff decisions; (2) A study to evaluate the log-likelihood criterion towards decision considerations to perform the hard handoff; (3) Development of a...
Show moreThe research proposed and elaborated in this dissertation is concerned with the development of new decision algorithms for hard handoff strategies in mobile communication systems. Specifically, the research tasks envisaged include the following: (1) Use of information-theoretics based statistical distance measures as a metric for hard handoff decisions; (2) A study to evaluate the log-likelihood criterion towards decision considerations to perform the hard handoff; (3) Development of a statistical model to evaluate optimum instants of measurements of the metric used for hard handoff decision. The aforesaid objectives refer to a practical scenario in which a mobile station (MS) traveling away from a serving base station (BS-I) may suffer communications impairment due to interference and shadowing affects, especially in an urban environment. As a result, it will seek to switch over to another base station (BS-II) that facilitates a stronger signal level. This is called handoff procedure. (The hard handoff refers to the specific case in which only one base station serves the mobile at the instant of handover). Classically, the handoff decision is done on the basis of the difference between received signal strengths (RSS) from BS-I and BS-II. The algorithms developed here, in contrast, stipulate the decision criterion set by the statistical divergence and/or log-likelihood ratio that exists between the received signals. The purpose of the present study is to evaluate the relative efficacy of the conventional and proposed algorithms in reference to: (i) Minimization of unnecessary handoffs ("ping-pongs"); (ii) Minimization of delay in handing over; (iii) Ease of implementation and (iv) Minimization of possible call dropouts due to ineffective handover envisaged. Simulated results with data commensurate with practical considerations are furnished and discussed. Background literature is presented in the introductory chapter and scope for future work is identified via open questions in the concluding chapter.
Show less - Date Issued
- 2000
- PURL
- http://purl.flvc.org/fcla/dt/12639
- Subject Headings
- Mobile communication systems, Information theory, Algorithms
- Format
- Document (PDF)
- Title
- Innovative video error resilient techniques for MBMS systems.
- Creator
- Sanigepalli, Praveen., Florida Atlantic University, Kalva, Hari, Furht, Borko, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
In the current communications age, the capabilities of mobile devices are increasing. The mobiles are capable of communicating at data rates of hundreds of mbps on 4G networks. This enables playback of rich multimedia content comparable to internet and television networks. However, mobile networks need to be spectrum-efficient to be affordable to users. Multimedia Broadcast Multicast Systems (MBMS) is a wireless broadcasting standard that is being drafted to enable multimedia broadcast while...
Show moreIn the current communications age, the capabilities of mobile devices are increasing. The mobiles are capable of communicating at data rates of hundreds of mbps on 4G networks. This enables playback of rich multimedia content comparable to internet and television networks. However, mobile networks need to be spectrum-efficient to be affordable to users. Multimedia Broadcast Multicast Systems (MBMS) is a wireless broadcasting standard that is being drafted to enable multimedia broadcast while focusing on being spectrum-efficient. The hybrid video coding techniques facilitate low bitrate transmission, but result in dependencies across frames. With a mobile environment being error prone, no error correction technique can guarantee error free transmission. Such errors propagate, resulting in quality degradation. With numerous mobiles sharing the broadcast session, any error resilient scheme should account for heterogeneous device capabilities and channel conditions. The current research on wireless video broadcasting focuses on network based techniques such as FEC and retransmissions, which add bandwidth overhead. There is a need to design innovative error resilient techniques that make video codec robust with minimal bandwidth overhead. This Dissertation introduces novel techniques in the area of MBMS systems. First, robust video structures are proposed in Periodic Intra Frame based Prediction (PIFBP) and Periodic Anchor Frame based Prediction (PAFBP) schemes. In these schemes, the Intra frames or anchor frames serve as reference frames for prediction during GOP period. The intermediate frames are independent of others; any errors in such frames are not propagated, thereby resulting in error resilience. In prior art, intra block rate is adapted based on the channel characteristics for error resilience. This scheme has been generalized in multicasting to address a group of users sharing the same session. Average packet loss is used to determine the intra block rate. This improves performance of the overall group and strives for consistent performance. Also, the inherent diversity in the broadcasting session can be used for its advantage. With mobile devices capable of accessing a WLAN during broadcast, they form an adhoc network on a WLAN to recover lost packets. New error recovery schemes are proposed for error recovery and their performance comparison is presented.
Show less - Date Issued
- 2005
- PURL
- http://purl.flvc.org/fcla/dt/12187
- Subject Headings
- Wireless communication systems, Signal processing, Digital video, Multimedia systems, Digital communications, Data transmission systems
- Format
- Document (PDF)
- Title
- Interactive computer aided digital control design.
- Creator
- Yakali, Huseyin Hakan., Florida Atlantic University, Roth, Zvi S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
This thesis outlines the design philosophy and implementation aspects of a new interactive CAD tool implemented in BASIC language on an IBM PC/AT computer for single input single output (SISO) digital control systems. The direct Digital Control design method presented is classical in nature. The program main features are: (1) The use of Modified z-transform to model the effects of transport delay due to control computation time. (2) The use of windows on a split screen to allow the designer...
Show moreThis thesis outlines the design philosophy and implementation aspects of a new interactive CAD tool implemented in BASIC language on an IBM PC/AT computer for single input single output (SISO) digital control systems. The direct Digital Control design method presented is classical in nature. The program main features are: (1) The use of Modified z-transform to model the effects of transport delay due to control computation time. (2) The use of windows on a split screen to allow the designer observation of the closed-loop step response while systematically shaping a root locus or synthesizing closed-loop pole/zero patterns. (3) Display of system response in between sampling instants.
Show less - Date Issued
- 1988
- PURL
- http://purl.flvc.org/fcla/dt/14488
- Subject Headings
- Computer-aided design, Digital control systems, Engineering design--Data processing
- Format
- Document (PDF)
- Title
- Integrating Multi-user Scheduling with Retransmission Diversity over Wireless Links.
- Creator
- Li, Irena, Zhuang, Hanqi, Wang, Xin, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Research presented in this thesis develops a mainly theoretical basis and computer models for enhancing the throughput of multi-user wireless communication networks. The cross-layer combination of an adaptive modulation and coding (AMC) scheme at the physical layer and the use of automatic repeat request (ARQ) retransmi ssions at the data link layer is integrated into a scheduling framework for multi-user networks. Scheduling algorithms incorporating retransmission diversity are derived for...
Show moreResearch presented in this thesis develops a mainly theoretical basis and computer models for enhancing the throughput of multi-user wireless communication networks. The cross-layer combination of an adaptive modulation and coding (AMC) scheme at the physical layer and the use of automatic repeat request (ARQ) retransmi ssions at the data link layer is integrated into a scheduling framework for multi-user networks. Scheduling algorithms incorporating retransmission diversity are derived for three cases of typical network traffic: best-effort, non-realtime, and realtime. For each case, numeric computer si mulations of wireless communications over Nakagami-m block fading channels are developed to examine the effectiveness of the formulated schemes.
Show less - Date Issued
- 2008
- PURL
- http://purl.flvc.org/fau/fd/FA00012533
- Subject Headings
- Wireless communication networks, Code division multiple access, Modulation (Electronics), Signal processing (Digital techniques)
- Format
- Document (PDF)
- Title
- Information hiding: Digital watermarking techniques.
- Creator
- Sadicoff, Mauricio Levy., Florida Atlantic University, Larrondo-Petrie, Maria M., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Digital Watermarking is a multimedia technique recently developed with the purpose of enhancing copyright protection on multimedia files. This thesis presents a survey of digital watermark features and classifications. It also proposes a classification method that includes most of previous classifications. The thesis then proceeds to detail two digital watermarking methods, Lower Significant Bit Encoding and Spread Spectrum Encoding. Software is designed and implemented to show the...
Show moreDigital Watermarking is a multimedia technique recently developed with the purpose of enhancing copyright protection on multimedia files. This thesis presents a survey of digital watermark features and classifications. It also proposes a classification method that includes most of previous classifications. The thesis then proceeds to detail two digital watermarking methods, Lower Significant Bit Encoding and Spread Spectrum Encoding. Software is designed and implemented to show the capabilities and behavior of each method. The software also shows how each method reacts to four typical transformations (attacks). The results of applying the two methods and their survival rates against the typical transformations are discussed in detail. Finally, the source code for the software is made available.
Show less - Date Issued
- 2002
- PURL
- http://purl.flvc.org/fcla/dt/12897
- Subject Headings
- Computer software--Development, Digital watermarking, Data encryption (Computer science)
- Format
- Document (PDF)
- Title
- Extensions to real-time object-oriented software design methodologies.
- Creator
- Woodcock, Timothy G., Florida Atlantic University, Fernandez, Eduardo B., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Real-time systems are systems where time is considered a system resource that needs to be managed. Time is usually represented in these systems as a deadline to complete a task. Unfortunately, by adding timing to even simple algorithms, it complicates them greatly. Real-time systems are by nature difficult and complex to understand. Object-oriented methodologies have attributes that allow real-time systems to be designed and implemented with less error and some control over the resultant...
Show moreReal-time systems are systems where time is considered a system resource that needs to be managed. Time is usually represented in these systems as a deadline to complete a task. Unfortunately, by adding timing to even simple algorithms, it complicates them greatly. Real-time systems are by nature difficult and complex to understand. Object-oriented methodologies have attributes that allow real-time systems to be designed and implemented with less error and some control over the resultant complexity. With object-oriented design, the system is modeled in the environment that it will be used in. Objects themselves, are partitions of the system, into logical, understandable units. In this dissertation, we start by surveying the current real-time object-oriented design methodologies. By comparing these methodologies and developing a set of criteria for evaluating them, we discover that certain aspects of these methodologies still need some work. The most important aspects of the methodologies are understanding the effects of deadlines on statechart behavioral models and understanding the effects of deadlines when object models are inherited or undergo aggregation. The effects of deadlines on statecharts are then explored in detail. There are two basic ways that deadlines are added to statecharts. The first, and most popular, is adding timing as a condition on a state transition. The second is adding a count down timer to a state and forcing a transition if the timer reaches zero. We show that these are equivalent and can be used interchangeably to simplify designs. Next, the effects of deadlines on behavior models when the corresponding object models undergo inheritance or aggregation are studied. We will first analyze the effects on the behavior model when object inheritance is encountered. We found eight ways that the behavior model can be modified and still maintain the properties of inheritance. Finally, deadlines are added and the analysis is repeated.
Show less - Date Issued
- 1996
- PURL
- http://purl.flvc.org/fcla/dt/12493
- Subject Headings
- Real-time data processing, Computer software--Development, Object-oriented programming (Computer science)
- Format
- Document (PDF)
- Title
- Mitigating worm propagation on virtual LANs.
- Creator
- Sun, Xiaoguang., Florida Atlantic University, Rajput, Saeed, Hsu, Sam, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
Recent worms have used sophisticated propagation techniques to propagate faster than the patch distribution and have utilized previously unknown vulnerabilities. To mitigate repetition of such epidemics in future, active defense mechanisms are needed that not only identify malicious activity, but can also defend against widespread outbreak. We provide a framework capable of reacting quickly to quarantine infections. The fundamental components of our framework are detector and VLAN switch. We...
Show moreRecent worms have used sophisticated propagation techniques to propagate faster than the patch distribution and have utilized previously unknown vulnerabilities. To mitigate repetition of such epidemics in future, active defense mechanisms are needed that not only identify malicious activity, but can also defend against widespread outbreak. We provide a framework capable of reacting quickly to quarantine infections. The fundamental components of our framework are detector and VLAN switch. We have provided a proof of concept implementation, where we use the Blaster worm as an example, and demonstrate that detection of worms is possible, and individual infected hosts can be isolated quickly. Furthermore, using Monte Carlo simulations, we show that such containment of future epidemics is possible. In addition, we also compute the overhead of detection and mitigation approaches and have shown that our approach has lower overhead compared to the others.
Show less - Date Issued
- 2006
- PURL
- http://purl.flvc.org/fcla/dt/13369
- Subject Headings
- Wireless LANs--Security measures, Wireless communication systems--Security measures, Computer viruses--Prevention, Computer security
- Format
- Document (PDF)
- Title
- Modeling and measurement of the response of small antennas near multilayered two or three-dimensional dielectric bodies.
- Creator
- Ponce de Leon, Lorenzo Angel., Florida Atlantic University, Helmken, Henry, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
- Abstract/Description
-
A theory of the circular loop antenna constructed from finite conductivity wire is developed via a Fourier series expansion of the currents in the loop. Models for a family of small loop antennas are also presented. A new high sensitivity and selectivity heterodyne fiber optic based electromagnetic field detector is developed compatible with open antenna range measurements made at low signal levels and in the presence of strong interfering signals. A new analytical solution pertaining to the...
Show moreA theory of the circular loop antenna constructed from finite conductivity wire is developed via a Fourier series expansion of the currents in the loop. Models for a family of small loop antennas are also presented. A new high sensitivity and selectivity heterodyne fiber optic based electromagnetic field detector is developed compatible with open antenna range measurements made at low signal levels and in the presence of strong interfering signals. A new analytical solution pertaining to the response of a disk loaded dipole antenna representing a dipole configured on a lossy dielectric medium is developed using a field compensation theorem and a geometrical theory of diffraction. The multipole expansions for the scattered fields of a multilayered infinite cylinder illuminated by oblique incidence plane wave are formulated and programmed for numerical analysis. The response of cylinders with constitutive parameters reflecting those used in human phantoms are calculated. The response of a small antenna proximal to a multilayered cylinder is analyzed. The scattered fields from multilayered bodies are coupled to a small wire antenna using a combined methods induced electromagnetic force (EMF) technique. New results concerning the response of a loop antenna near a multilayered body obtained via a zero and first phase current model are presented. The new technique is applied in the analysis of human phantoms tested in an open field antenna range. Validation of the theory of multilayered human phantoms with measurements using the new detector is demonstrated.
Show less - Date Issued
- 1992
- PURL
- http://purl.flvc.org/fcla/dt/12294
- Subject Headings
- Antennas (Electronics)
- Format
- Document (PDF)
