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Title: Gaussian beam resonator formalism using the yy method.
Creator: Menard, Kenneth A., Harvey, James E, Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; A simple and powerful new paraxial ray formalism is shown to provide an alternate method for designing Gaussian Beam Resonators. The theory utilizes the Delano yybar diagram approach and is an extension of the recent work by Shack and Kessler for laser systems. The method is shown to be complementary to the conventional ABCD method and is founded upon J.A. Arnaud's pioneering ideas for complex rays. The thesis develops an analytic...
Show moreUniversity of Central Florida College of Engineering Thesis; A simple and powerful new paraxial ray formalism is shown to provide an alternate method for designing Gaussian Beam Resonators. The theory utilizes the Delano yybar diagram approach and is an extension of the recent work by Shack and Kessler for laser systems. The method is shown to be complementary to the conventional ABCD method and is founded upon J.A. Arnaud's pioneering ideas for complex rays. The thesis develops an analytic formulation of a ray based complex wavefront curvature and yields a clearly generalized description of spherical wave propagation, for which Gaussian beams are considered a special case. The resultant theory unifies the complex q parameter and the ABCD law, with the yybar complex ray components and also suggests that the ABCD law for the complex q parameter has its origin in the yybar complex ray. New fundamental equations for designing stable multi-element resonators using the yybar coordinates are derived, and it is shown that the yybar diagram provides a novel method for defining automatically stable resonators. Various applications for the yybar design technique are also discussed, including the setting of convenient design constraints, the description of M2 beams, generating phase diagrams, and resonator synthesis and analysis.
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Date Issued: 1995
Identifier: CFR0011940, ucf:53106
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011940

Title: Electromagnetic focusing properties of chirped metallic gratings.
Creator: Schmidt, Jeffrey C., Christodoulou, Christos G., Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; The focusing properties of chirped diffraction gratings have long been studied and often used in applications at optical frequencies. Chirped metallic gratings of this type have also been studied theoretically at microwave frequencies, but no attempt has been made to experimentally examine or utilize the focusing properties of these structures at microwave frequencies. This thesis presents an experimental analysis of the focusing...
Show moreUniversity of Central Florida College of Engineering Thesis; The focusing properties of chirped diffraction gratings have long been studied and often used in applications at optical frequencies. Chirped metallic gratings of this type have also been studied theoretically at microwave frequencies, but no attempt has been made to experimentally examine or utilize the focusing properties of these structures at microwave frequencies. This thesis presents an experimental analysis of the focusing properties of chirped metallic gratings. These gratings are designed to focus electromagnetic energy at a predetermined position by varying strip width and spacing as a function of position. The diffraction gratings are characterized, and experimentally measured results are compared to theoretical data.
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Date Issued: 1992
Identifier: CFR0011931, ucf:53123
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011931

Title: Integration of artificial neural networks and simulation modeling in a decision support system.
Creator: LeCroy, Kenney, Mollaghasemi, Mansooreh, Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; A simulation based decision support system is developed for AT[and]T Microelectronics in Orlando. This system uses simulation modeling to capture the complex nature of semiconductor test operations. Simulation, however, is not a tool for optimizations by itself. Numerous executions of the simulation model must generally be performed to narrow in on a set of proper decision parameters. As a means of alleviating this shortcoming,...
Show moreUniversity of Central Florida College of Engineering Thesis; A simulation based decision support system is developed for AT[and]T Microelectronics in Orlando. This system uses simulation modeling to capture the complex nature of semiconductor test operations. Simulation, however, is not a tool for optimizations by itself. Numerous executions of the simulation model must generally be performed to narrow in on a set of proper decision parameters. As a means of alleviating this shortcoming, artificial neural networks are used in conjunction with simulation modeling to aid management in the decision making process. The integration of simulation and neural networks in a comprehensive decision support system, in effect, learns the reverse of the simulation process. That is, given a set of goals defined for performance measures, the decision support system suggests proper values for decision parameters to achieve those goals.
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Date Issued: 1994
Identifier: CFR0011935, ucf:53114
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011935

Title: Efficient techniques for management and delivery of video data.
Creator: Oh, Junghwan, Hua, Kien A., Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; The rapid advances in electronic imaging, storage, data compression telecommunications, and networking technology have resulted in a vast creation and use of digital videos in many important applications such as digital libraries, distance learning, public information systems, electronic commerce, movie on demand, etc. This brings about the need for management as well as delivery of video data. Organizing and managing video data,...
Show moreUniversity of Central Florida College of Engineering Thesis; The rapid advances in electronic imaging, storage, data compression telecommunications, and networking technology have resulted in a vast creation and use of digital videos in many important applications such as digital libraries, distance learning, public information systems, electronic commerce, movie on demand, etc. This brings about the need for management as well as delivery of video data. Organizing and managing video data, however, is much more complex than managing conventional text data due to their semantically rich and unstructured contents. Also, the enormous size of video files requires high communication bandwidth for data delivery. In this dissertation, I present the following techniques for video data management and delivery. Decomposing video into meaningful pieces (i.e., shots) is a very fundamental step to handling the complicated contents of video data. Content-based video parsing techniques are presented and analyzed. In order to reduce the computation cost substantially, a non-sequential approach to shot boundary detection is investigated. Efficient browsing and indexing of video data are essential for video data management. Non-linear browsing and cost-effective indexing schemes for video data based on their contents are described and evaluated. In order to satisfy various user requests, delivering long videos through the limited capacity of bandwidth is challenging work. To reduce the demand on this bandwidth, a hybrid of two effective approaches, periodic broadcast and scheduled multicast, is discussed and simulated. The current techniques related to the above works are discussed thoroughly to explain their advantages and disadvantages, and to make the new improved schemes. The substantial amount of experiments and simulations as well as the concepts are provided to compare the introduced techniques with the other existing ones. The results indicate that they outperform recent techniques by a significant margin. I conclude the dissertation with a discussing of future research directions.
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Date Issued: 2000
Identifier: CFR0001719, ucf:52918
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0001719

Title: Development and saw device implementation of a new weighted stepped chirp code signal for direct sequence spread spectrum communications systems.
Creator: Carter, Scott Edward, Malocha, Donald C., Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; This work introduces the new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudonoise (PN) cose and equivalent performance and easier implementation than a CW chirp. This...
Show moreUniversity of Central Florida College of Engineering Thesis; This work introduces the new weighted stepped chirp code signal for direct sequence spread spectrum (DS/SS) communications systems. This code signal uses the truncated cosine series functions as the chip functions. This code signal is the result of discretizing a continuous wave (CW) chirp which results in enhanced performance versus a pseudonoise (PN) cose and equivalent performance and easier implementation than a CW chirp. This code signal will be shown to possess improved compression ratio (CR), peak sidelobe level (PSL), integrated sidelobe level (ISL), and bit error rate (BER) when compared to a PN code of identical code length and chip length. It also will be shown to have a similar CR, PSL, ISL, and loss in processing gain (LPG) when compared to a CW chirp with identical pulse length and frequency deviation. The code signal is implemented on surface acoustic wave (SAW) devices which can be used as the code signal generator at the transmitter and the correlator at the receiver in a DS/SS communication system. SAW design considerations for the weighted stepped chirp signal are discussed. Experimental data is presented and compared to the predicted CR, PSL, ISL, LPG, and BER.
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Date Issued: 1998
Identifier: CFR0008153, ucf:52944
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0008153

Title: High frequency communication system modeling and performance enhancement, employing novel adaptive DSP techniques.
Creator: Qahwash, Murad M., Mikhael, Wasfy, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; High Frequency (HF) communication has been shown to be a useful communication technique from the very beginning of World War I and it accelerated during World War II. This is attributed to its simplicity, ability to provide near globe connectivity at low power without repeaters, moderate cost, and ease of proliferation [I]. In fact, the HF communication system utilizes the ionosphere [2][3][4] to refract the skywave signals to a...
Show moreUniversity of Central Florida College of Engineering Thesis; High Frequency (HF) communication has been shown to be a useful communication technique from the very beginning of World War I and it accelerated during World War II. This is attributed to its simplicity, ability to provide near globe connectivity at low power without repeaters, moderate cost, and ease of proliferation [I]. In fact, the HF communication system utilizes the ionosphere [2][3][4] to refract the skywave signals to a distant receiver. This ionospheric channel has some disadvantages. First, it is a non-stationary channel as the HF frequency propagation is a function of the sun spot activities, solar winds, and diurnal variations of the ionization level [5]. Second, the channel produces distortion in both signal amplitude and phase. As the different ionospheric layers move up or down, independent Doppler shifts on each propagation mode are introduced. Multipath fading [6] caused by multiple refractions of the signal fiom the ionosphere with or without ground reflection causes performance degradation in the HF system. Some techniques have been developed to improve HF performance [I]. One example is Space-Diversity [7], which uses more than one antenna at distant spaces to combine the received signal. Angle-of-Arrival Diversity that takes advantage of the fact that different modes have different arrival angles at the receiver, and so, highly directional antenna for example, can be used to improve the system performance. Another method of improving HF performance is to use different frequencies to transmit and receive messages. This method is known as Frequency diversity. Using timediversity, one can add a degree of redundancy to the transmitted message through the use of different types of coding, interleaving, etc. In the military standard, MIL-STD- 1 88- 1 1 OA [8], a convolutional encoder [9][10] followed by interleaver [Ill-[14] was used to scramble and transmit the data in different bit rates. In the presence of multipath fading [ 1 51, a training sequence is transmitted in an interleaved fashion with the data symbols with a 50% duty cycle. This has the disadvantage of losing half the bandwidth. At present, the recent advances of the Digital Signal Processing (DSP) [16][17] make it possible to reduce the bit-error-rate BEY and increase the transmission bit rate [18] through the usage of adaptive equalization [ 191-[2 11 which will be the focus of this dissertation. Equalizers such as, Transversal Equalizer [ 1 61, Blind Equalizer [22], Training waveform Equalizer [23], and Minimum Mean Square Error (MMSE) [20] Adaptive Equalizer have been applied into various communication systems. This proposal work will be to initially apply some of the previous developed equalizer to the HF channel specifically. Thereafter, new adaptive channel equalization [24],[25] will be developed to compensate for transmission channel impairments due to bandwidth limitations, multipath propagation, and rayleigh fading [2 11 conditions in mobile environments. A new technique for frequency offset prediction has been developed and finally, a new approach for MIL-STD- 1 88- 1 1 0A high frequency single-tone modem employing orthogonal Walsh-PN codes has been implemented.
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Date Issued: 2002
Identifier: CFR0000759, ucf:52934
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0000759

Title: Low voltage regulator modules and single stage front-end converters.
Creator: Gu, Wei, Batarseh, Issa, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; Evolution in microprocessor technology poses new challenges for supplying power to these devices. To meet demands for faster and more efficient data processing, modem microprocessors are being designed with lower voltage implementations. More devices will be packed on a single processor chip and the processors will operate at higher frequencies, exceeding IGHz. New high performance microprocessors may require from 40 to 80 watts of...
Show moreUniversity of Central Florida College of Engineering Thesis; Evolution in microprocessor technology poses new challenges for supplying power to these devices. To meet demands for faster and more efficient data processing, modem microprocessors are being designed with lower voltage implementations. More devices will be packed on a single processor chip and the processors will operate at higher frequencies, exceeding IGHz. New high performance microprocessors may require from 40 to 80 watts of power for the CPU alone. Load current must be supplied with up to 30A/us slew rate while keeping the output voltage within tight regulation and response time tolerances. Therefore, special power supplies and Voltage Regulator Modules (VRMs) are needed to provide lower voltage with higher current and fast response.
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Date Issued: 2001
Identifier: CFR0000194, ucf:52938
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0000194

Title: Antenna-coupled infrared focal plane array.
Creator: Gonzalez, Francisco Javier, Boreman, Glenn D., Engineering and Computer Sciences
Abstract / Description: University of Central Florida College of Engineering Thesis; In this dissertation a new type of infared focal plan array (IR FPA) was investigated, consisting of antenna-coupled microbolometer fabricated using electron-beam lithography. Four different antenna designs were experimentally demonstrated at 10-micron wavelength: dipole, bowtie, square-spiral, and log-periodic. The main differences between these antenna types were their bandwidth, collection area, angular reception pattern, and...
Show moreUniversity of Central Florida College of Engineering Thesis; In this dissertation a new type of infared focal plan array (IR FPA) was investigated, consisting of antenna-coupled microbolometer fabricated using electron-beam lithography. Four different antenna designs were experimentally demonstrated at 10-micron wavelength: dipole, bowtie, square-spiral, and log-periodic. The main differences between these antenna types were their bandwidth, collection area, angular reception pattern, and polarization. To provide pixel collection areas commensurate with typical IR FPA requirements, two configuration were investigated: a two-dimensional serpentine interconnection of individual IR antennas, and a Fresnel-zone-plate (FZP) coupled to a single-element antenna. Optimum spacing conditions for the two-dimensional interconnect were developed. Increased sensitivity was demonstrated using a FZP-coupled design. In general, it was found that the configuration of the antenna substrate material was critical for optimization of sensitivity. The best results were obtained using this membranes of silicon nitride to enhance the thermal isolation of the antenna-coupled bolometers. In addition, choice of the bolometer material was also important, with the best results obtained using vanadium oxide. Using optimum choices for all parameters, normalized sensitivity (D*) values in the range of mid 10^8 [cmâˆšHz/W] were demonstrated for antenna-coupled IR sensors, and directions for further improvements were identified. Successful integration of antenna-coupled pixels with commercial readout integrated circuits was also demonstrated.
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Date Issued: 2003
Identifier: CFR0011595, ucf:53049
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011595

Title: Finite impulse response filter design using cosine series functions.
Creator: Bishop, Carlton Delos, Malocha, Donald C., Engineering
Abstract / Description: Window functions have been extensively used for the design of SAW filters. The classical truncated cosine series functions, such as the Hamming and Blackmann functions, are only a few of an infinite set of such functions. The derivation of this set of functions from orthonormal basis sets and the criteria for obtaining the constant coefficients of the functions are presented. These functions are very useful because of the closed-form expressions and their easily recognizable Fourier transform...
Show moreWindow functions have been extensively used for the design of SAW filters. The classical truncated cosine series functions, such as the Hamming and Blackmann functions, are only a few of an infinite set of such functions. The derivation of this set of functions from orthonormal basis sets and the criteria for obtaining the constant coefficients of the functions are presented. These functions are very useful because of the closed-form expressions and their easily recognizable Fourier transform. Another approach to the design of Gaussian shaped filters having a desired sidelobe level using a 40 term cosine series will be presented as well. This approach is again non-iterative and a near equi-ripple sidelobe level filter could be achieved. A deconvolution technique will also be presented. this has the advantage of being non-iterative, simple and fast. This design method produces results comparable to the Dolph-Chebyshev technique.
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Date Issued: 1988
Identifier: CFR0013088, ucf:53133
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0013088

Title: An adaptive integration architecture for software reuse.
Creator: Williams, Denver Robert Edward, Orooji, Ali, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; The problem of building large, reliable software systems in a controlled, cost effective way, the so-called software crisis problem, is one of computer science's great challenges. From the very outset of computing as science, software reuse has been touted as a means to overcome the software crisis issue.
Date Issued: 2001
Identifier: CFR0000786, ucf:52928
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0000786

Title: Dynamic modeling of pwm and single-switch single-stage power factor correction converters.
Creator: Zhu, Guangyong, Batarseh, Issa E., Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; The concept of averaging has been used extensively in the modeling of power electronic circuits to overcome their inherent time-variant nature. Among various methods, the PWM switch modeling approach is most widely accepted in the study of closed-loop stability and transient response because of its accuracy and simplicity. However, a non-ideal PWM switch model considering conduction losses is not available except for converters...
Show moreUniversity of Central Florida College of Engineering Thesis; The concept of averaging has been used extensively in the modeling of power electronic circuits to overcome their inherent time-variant nature. Among various methods, the PWM switch modeling approach is most widely accepted in the study of closed-loop stability and transient response because of its accuracy and simplicity. However, a non-ideal PWM switch model considering conduction losses is not available except for converters operating in continuous conduction mode (CCM) and under small ripple conditions. Modeling of conductor losses under large ripple conditions has not been reported in the open literature, especially when the converter operates in discontinuous conduction mode (DCM). In this dissertation, new models are developed to include conduction losses in the non-ideal PWM switch model under CCM and DCM conditions. The developed model is verified through two converter examples and the effect of conduction losses on the steady state and dynamic responses of the converter is also studied. Another major constraint of the PWM switch modeling approach is that it heavily relies on finding the three-terminal PWM switch. This requirement severely limits its application in modeling single-switch single-stage power factor correction (PFC) converters, where more complex topological structures and switching actions are often encountered. In this work, we developed a new modeling approach which extends the PWM switch concept by identifying the charging and discharging voltages applied to the inductors. The new method can be easily applied to derive large-signal models for a large group of PFC converters and the procedure is elaborated through a specific example. Finally, analytical results regarding harmonic contents and power factors of various PWM converters in PFC applications are also presented here.
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Date Issued: 1999
Identifier: CFR0001716, ucf:52925
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0001716

Title: Gate and throughput optimizations for null convention self-timed digital circuits.
Creator: Smith, Scott Christopher, DeMara, Ronald, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; Convention Logic (NCL) provides an asynchronous design methodology employing dual-rail signals, quad-rail signals, or other Mutually Exclusive Assertion Groups (MEAGs) to incorporate data and control information into one mixed path. In NCL, the control is inherently present with each datum, so there is no need for worse case delay analysis and control path delay matching. This dissertation focuses on optimization methods for NCL...
Show moreUniversity of Central Florida College of Engineering Thesis; Convention Logic (NCL) provides an asynchronous design methodology employing dual-rail signals, quad-rail signals, or other Mutually Exclusive Assertion Groups (MEAGs) to incorporate data and control information into one mixed path. In NCL, the control is inherently present with each datum, so there is no need for worse case delay analysis and control path delay matching. This dissertation focuses on optimization methods for NCL circuits, specifically addressing three related architectural areas of NCL design. First, a design method for optimizing NCL circuits is developed. The method utilizes conventional Boolean minimization followed by table-driven gate substitutions. It IS applied to design time and space optimal fundamental logic functions, a time and space optimal full adder, and time, transistor count, and power optimal up-counter circuits. The method is applicable when composing logic functions where each gate is a state-holding element; and can produce delay-insensitive circuits requiring less area and fewer gate delays than alternative gate-level approaches requiring full minterm generation. Second, a pipelining method for producing throughput optimal NCL systems is developed. A relationship between the number of gate delays per stage and the worse case throughput for a pipeline as a whole is derived. The method then uses this relationship to minimize a pipeline's worse-case throughput by partitioning the NCL combinational circuitry through the addition of asynchronous registers. The method is applied to design a maximum throughput unsigned multiplier, which yields a speedup of 2.25 over the non-pipelined version, while maintaining delay-insensitivity. Third, a technique to mitigate the impact of the NULL cycle is developed. The technique Wher increases the maximum attainable throughput of a NCL system by reducing inherent overheads associated with an integrated data and control path. This technique is applied to a non-pipelined Cbit by 4-bit unsigned multiplier to yield a speedup of 1.61 over the standalone version. Finally, these techniques are applied to design a 72+32x32 multiply and &cumulate (MAC) unit, which outperforms other delay-insensitive/self-timed MACs in the literature. It also performs conditional rounding, scaling, and saturation of the output, whereas the others do not; thus further distinguishing it from the previous work. The methods developed facilitate speed, transistor count, and power tradeoffs using approaches that are readily automatable.
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Date Issued: 2001
Identifier: CFR0001377, ucf:52924
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0001377

Title: Topology and control investigation for low-voltage high-current isolated DC-DC converters.
Creator: Mao, Hong, Batarseh, Issa, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; High conversion efficiency and fast transient response at high switching frequency are the two main challenges for low-voltage high-current DC-DC converters, which are the motivations of the dissertation work. To reduce the switching power loss, soft switching is a desirable technique to keep power loss under control at high switching frequencies. A Duty-Cycle-Shift (DCS) concept is proposed for half-bridge DC-DC converters to...
Show moreUniversity of Central Florida College of Engineering Thesis; High conversion efficiency and fast transient response at high switching frequency are the two main challenges for low-voltage high-current DC-DC converters, which are the motivations of the dissertation work. To reduce the switching power loss, soft switching is a desirable technique to keep power loss under control at high switching frequencies. A Duty-Cycle-Shift (DCS) concept is proposed for half-bridge DC-DC converters to reduce switching loss. The concept of this new control scheme is shifting one of the two symmetric PWM driving signals close to the other, such that ZVS can be achieved for the lagging switch due to the shortened resonant interval.
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Date Issued: 2004
Identifier: CFR0001718, ucf:52921
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0001718

Title: Computing a diameter-constrained minimum spanning tree.
Creator: Abdalla, Ayman Mahmoud, Deo, Narsingh, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; In numerous practical applications, it is necessary to find the smallest possible tree with a bounded diameter. A diameter-constrained minimum spanning tree (DCMST) of a given undirected, edge-weighted graph, G, is the smallest-weight spanning tree of all spanning trees of G which contain no path with more than k edges, where k is a given positive integer. The problem of finding a DCMST is NP-complete for all values of k; 4
Show moreUniversity of Central Florida College of Engineering Thesis; In numerous practical applications, it is necessary to find the smallest possible tree with a bounded diameter. A diameter-constrained minimum spanning tree (DCMST) of a given undirected, edge-weighted graph, G, is the smallest-weight spanning tree of all spanning trees of G which contain no path with more than k edges, where k is a given positive integer. The problem of finding a DCMST is NP-complete for all values of k; 4 <= k <= (n - 2), except when all edge-weights are identical. A DCMST is essential for the efficiency of various distributed mutual exclusion algorithms, where it can minimize the number of messages communicated among processors per critical section. It is also useful in linear lightwave networks, where it can minimize interference in the network by limiting the traffic in the network lines. Another practical application requiring a DCMST arises in data compression, where some algorithms compress a file utilizing a data-structure, and decompress a path in the tree to access a record A DCMST helps such algorithm to be fast without sacrificing a lot of storage storage space.
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Date Issued: 2001
Identifier: CFR0002215, ucf:52914
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0002215

Title: Energy aware design and analysis for synchronous and asynchronous circuits.
Creator: Di, Jia, Yuan, Jiann S., Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; Power dissipation has become a major concern for IC designers. Various low power design techniques have been developed for synchronous circuits. Asynchronous circuits, however have gained more interests recently due to their benefits in lower noise, easy timing control, etc. But few publications on energy reduction techniques for asynchronous logic are available. Power awareness indicates the ability of the system power to scale...
Show moreUniversity of Central Florida College of Engineering Thesis; Power dissipation has become a major concern for IC designers. Various low power design techniques have been developed for synchronous circuits. Asynchronous circuits, however have gained more interests recently due to their benefits in lower noise, easy timing control, etc. But few publications on energy reduction techniques for asynchronous logic are available. Power awareness indicates the ability of the system power to scale with changing conditions and quality requirements. Scalability is an important figure-of-merit since it allows the end user to implement operational policy just like the user of mobile multimedia equipment needs to select between better quality and longer battery operation time. This dissertation discusses power /energy optimization and performs analysis on both synchronous and asynchronous logic.
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Date Issued: 2004
Identifier: CFR0001720, ucf:52913
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0001720

Title: A unified approach to dynamic modeling of high switching frequency pwm converters.
Creator: Iannello, Christopher J., Batarseh, Issa, Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; This dissertation will present the development of a unified approach for dynamic modeling of the PWM and soft-switching power converters. Dynamic modeling of non-linear power converters is very important for the design and stability of their closed loop control. While the use of equivalent circuits is often preferred due to simulation efficiency issues, no unified and widely applicable method for the formulation of these equivalents...
Show moreUniversity of Central Florida College of Engineering Thesis; This dissertation will present the development of a unified approach for dynamic modeling of the PWM and soft-switching power converters. Dynamic modeling of non-linear power converters is very important for the design and stability of their closed loop control. While the use of equivalent circuits is often preferred due to simulation efficiency issues, no unified and widely applicable method for the formulation of these equivalents exists.
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Date Issued: 2001
Identifier: CFR0000833, ucf:52929
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0000833

Title: Video categorization using semantics and semiotics.
Creator: Rasheed, Zeeshan, Shah, Mubarak, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; There is a great need to automatically segment, categorize, and annotate video data, and to develop efficient tools for browsing and searching. We believe that the categorization of videos can be achieved by exploring the concepts and meanings of the videos. This task requires bridging the gap between low-level content and high-level concepts (or semantics). Once a relationship is established between the low-level computable...
Show moreUniversity of Central Florida College of Engineering Thesis; There is a great need to automatically segment, categorize, and annotate video data, and to develop efficient tools for browsing and searching. We believe that the categorization of videos can be achieved by exploring the concepts and meanings of the videos. This task requires bridging the gap between low-level content and high-level concepts (or semantics). Once a relationship is established between the low-level computable features of the video and its semantics, .the user would be able to navigate through videos through the use of concepts and ideas (for example, a user could extract only those scenes in an action film that actually contain fights) rat her than sequentially browsing the whole video. However, this relationship must follow the norms of human perception and abide by the rules that are most often followed by the creators (directors) of these videos. These rules are called film grammar in video production literature. Like any natural language, this grammar has several dialects, but it has been acknowledged to be universal. Therefore, the knowledge of film grammar can be exploited effectively for the understanding of films. To interpret an idea using the grammar, we need to first understand the symbols, as in natural languages, and second, understand the rules of combination of these symbols to represent concepts. In order to develop algorithms that exploit this film grammar, it is necessary to relate the symbols of the grammar to computable video features.
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Date Issued: 2003
Identifier: CFR0001717, ucf:52920
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0001717

Title: Larger-first partial parsing.
Creator: Van Delden, Sebastian Alexander, Gomez, Fernando, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; Larger-first partial parsing is a primarily top-down approach to partial parsing that is opposite to current easy-first, or primarily bottom-up, strategies. A rich partial tree structure is captured by an algorithm that assigns a hierarchy of structural tags to each of the input tokens in a sentence. Part-of-speech tags are first assigned to the words in a sentence by a part-of-speech tagger. A cascade of Deterministic Finite State...
Show moreUniversity of Central Florida College of Engineering Thesis; Larger-first partial parsing is a primarily top-down approach to partial parsing that is opposite to current easy-first, or primarily bottom-up, strategies. A rich partial tree structure is captured by an algorithm that assigns a hierarchy of structural tags to each of the input tokens in a sentence. Part-of-speech tags are first assigned to the words in a sentence by a part-of-speech tagger. A cascade of Deterministic Finite State Automata then uses this part-of-speech information to identify syntactic relations primarily ina descending order of their size. The cascade is divided into four specialized sections: (1) a Comma Network, which identifies syntactic relations associated with commas; (2) a Conjunction Network, which partially disambiguates phrasal conjunctions and fully disambiguates clausal conjunctions; (3) a Clause Network, which identifies non-comma-delimited clauses; and (4) a Phrase Network, which identifies the remaining base phrases in the sentence. Each automaton is capable of adding one ore more levels of structural tags to the to the tokens in a sentence. The larger-first approach is compared against a well-known easy-first approach. The results indicate that this larger-first approach is capable of (1) producing a more detailed partial parse than an easy first approach; (2) providing better containment of attachment ambiguity; (3) handling overlapping syntactic relations; and (4) achieving a higher accuracy than the easy-first approach. The automata of each network were developed by an empirical analysis of several sources and are presented here in details.
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Date Issued: 2003
Identifier: CFR0000760, ucf:52932
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0000760

Title: Crash quality- an approach for evaluating spending on quality improvement initiatives.
Creator: Ferreira, Labiche, Hosni, Yasser A., Engineering
Abstract / Description: University of Central Florida College of Engineering Thesis; The quality movement has become popular among corporations big and small for one reason: empirical evidence suggests that quality and productivity (and hence profitability) are linked. Unfortunately, while many firms accept that quality and productivity go together, few actually track the gains associated with their quality improvement programs. Companies also tend to spend on quality improvement with no indication of estimation of...
Show moreUniversity of Central Florida College of Engineering Thesis; The quality movement has become popular among corporations big and small for one reason: empirical evidence suggests that quality and productivity (and hence profitability) are linked. Unfortunately, while many firms accept that quality and productivity go together, few actually track the gains associated with their quality improvement programs. Companies also tend to spend on quality improvement with no indication of estimation of the impact of funding on the targeted process. It would be of great value to know: (1) the impact of spending to enhance the product/process quality level, and (2) the point at which expenditures for quality improvement are not economical. This research involves modeling the quality level of a product composed of integrated components/processes and the costs associated with quality improvement. Presented in this research is a methodology for determining the point at which the target quality level is reached. This point signifies when future spending should be re-directed. The research defines this point as the "Crash Quality Point (CQP)." Cases of a single process level and double level three-stage process are modeled to conceptualize CQP. The finding from the output analysis reveal that the quality level approaches the target level at varying points in time. Any spending beyond this point does not have an impact on the quality level compared to the period prior to the Crash Quality Point. Spending past this point is futile and these funds could be spent on the quality improvement projects. The special case modeled also illustrates the use of this tool in the selection of processes for improvements based on the quality level of the process. This is an added advantage in scenarios where funds are limited and management is constrained to improve process quality with limited funds. Using a real world example validates the proposed CQP methodology. The results of the validation indicate that the model developed can assist managers in forecasting the budget requirements for quality spending based on the quality improvement goals. The tool also enables managers to estimate the point in time at which allocations of funds may be directed for process reengineering. The CQP method will enable quality improvement professionals to determine the economical viability and the limits in expenditures on quality improvement. It enables managers to evaluate spending alternatives and approximate when the point of diminishing return is reached.
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Date Issued: 2000
Identifier: CFR0011594, ucf:53046
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011594

Title: On the design and performance of cognitive packets over wired networks and mobile ad hoc networks.
Creator: Lent, Marino Ricardo, Gelenbe, Erol, Engineering and Computer Science
Abstract / Description: University of Central Florida College of Engineering Thesis; This dissertation studied cognitive packet networks (CPN) which build networked learning systems that support adaptive, quality of service-driven routing of packets in wired networks and in wireless, mobile ad hoc networks.
Date Issued: 2003
Identifier: CFR0001374, ucf:52931
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0001374

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