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Title: Computer Method for Airport Noise Exposure Forecast.
Creator: Bateman, John M., Ventre, Gerald G., Engineering
Abstract / Description: Florida Technological University College of Engineering Thesis; The major problem facing air transportation for the next decade is aircraft noise. The noise level due to the operation of large jet aircraft has created a very serious annoyance problem to the people living near of adjacent to jet airports. The noise problem has developed both for take-off and landing operations of these aircraft with take -off noise causing the greatest annoyance factor. A technique called Noise Exposure...
Show moreFlorida Technological University College of Engineering Thesis; The major problem facing air transportation for the next decade is aircraft noise. The noise level due to the operation of large jet aircraft has created a very serious annoyance problem to the people living near of adjacent to jet airports. The noise problem has developed both for take-off and landing operations of these aircraft with take -off noise causing the greatest annoyance factor. A technique called Noise Exposure Forcast (NEF) has been developed to identify the annoyance factor of these noises to people and activities on the ground. With these NEF ratings or numbers, planners can better determined the type of buildings and activities to locate in the vicinity of airports. This paper presents a computer method for determining NEF areas or contours which eliminate the necessity of performing laborous hand calculations and iterations normally required to determine a given NEF locus about an airport. A land use compatability table showing land use versus NEF numbers is given on page 3. A sample computer program is given on pages 21 through 25 of teh appendix and a sample computer output page is given on page 26. The computer technique developed for this paper can be used for any airport.
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Date Issued: 1972
Identifier: CFR0012156, ucf:53130
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0012156

Title: Suppression of Turbofan and Turbojet Engine Generated Noise.
Creator: Master, Harry D., Ventre, Gerald G., Engineering
Abstract / Description: Florida Technological University College of Engineering Thesis; Every advance in the transformation of heat energy into mechanical energy has involved a noise problem, and in general it increases with the power production. The jet airplane is a good example: the large-scale turbulence of the exhaust gases in the jet forms an unusually intense source of sound the control of which is quite difficult. The additionally generated fan noises add characteristic fan tones which are particularly...
Show moreFlorida Technological University College of Engineering Thesis; Every advance in the transformation of heat energy into mechanical energy has involved a noise problem, and in general it increases with the power production. The jet airplane is a good example: the large-scale turbulence of the exhaust gases in the jet forms an unusually intense source of sound the control of which is quite difficult. The additionally generated fan noises add characteristic fan tones which are particularly noticeable on landing approaches. the human ear is the vulnerable receiver of these noises, and the problem becomes one of deciding how much jet engine noise reduction is required for the comfort or safety of the receiver, and then to devise ways to achieve it.
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Date Issued: 1972
Identifier: CFR0011987, ucf:53093
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011987

Title: A DERIVATION OF AN EMPIRICAL EQUATION FOR ESTIMATING THE ACOUSTICAL SHADOW ZONE LENGTH OF ROADWAY NOISE BARRIERS.
Creator: Arner, Wayne, Wayson, Roger, University of Central Florida
Abstract / Description: The objective of this research was to derive an empirical equation that estimates the acoustical shadow zone length (SZL) of roadway noise barriers. The acoustical shadow zone is the area behind a noise barrier of reduced sound levels, generally to some stated level at or near background. The ability to predict the SZL can be used as a method to evaluate the performance, and possibly the design, of roadway noise barriers. The current federally required roadway noise model is the Federal...
Show moreThe objective of this research was to derive an empirical equation that estimates the acoustical shadow zone length (SZL) of roadway noise barriers. The acoustical shadow zone is the area behind a noise barrier of reduced sound levels, generally to some stated level at or near background. The ability to predict the SZL can be used as a method to evaluate the performance, and possibly the design, of roadway noise barriers. The current federally required roadway noise model is the Federal Highway Administration (FHWA) Traffic Noise Model (TNM). TNM uses insertion loss (IL) to evaluate the effectiveness of a barrier. Insertion loss is the difference in sound level between the "no barrier" and the "with barrier" case. One major limitation with TNM is that the reported IL does not take into account how background noise levels influence the mitigated sound levels. Background noise can be defined as the noise present at a barrier location in the absence of roadway noise. The shadow zone represents a region behind the noise barrier where the barrier is effective at reducing noise levels and takes into account how background noise affects the IL and thus the SZL. The inclusion of background noise becomes significant in evaluating barrier effectiveness because as the distance from the barrier increases, background noise begins to overtake roadway noise as the dominate noise source. The derivation of the empirical equation began by collecting in-situ noise measurements at 18 noise barrier locations across Florida. The measured noise data was supplemented by noise data obtained from computer modeling. After a sufficient quantity of measured and modeled IL data was obtained, a contour of equal IL (IL = 5 dB) was plotted for each barrier location. The area defined by the contour is called the shadow zone. All the SZLs were statistically compared to several variables that were expected to influence it. Regression modeling showed that the background noise level, noise barrier height, the distance from the roadway to the noise barrier, and percent of heavy truck traffic volume were statistically significant as useful predictors of SZL. Two empirical equations were derived, one from linear regression and one from polynomial regression, and are referred to as the Shadow Zone Equations.
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Date Issued: 2006
Identifier: CFE0001464, ucf:47096
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001464

Title: DECOHERENCE IN QUANTUM DOT CHARGE QUBITS: THE ROLE OFELECTROMAGNETIC FLUCTUATIONS.
Creator: McCracken, James, Mucciolo, Eduardo, University of Central Florida
Abstract / Description: Lateral semiconductor quantum dot structures have been proposed as an effective quantum bit (qubit) for quantum computation. A single excess electron with the freedom to move between two capacitively coupled quantum dots creates a `pseudo'-spin system with the same qubit behavior as the more natural two level system of a single electron spin. The excess electron in the double dot system is restricted to one of the two dots, thereby creating two separate and distinct states (usually referred...
Show moreLateral semiconductor quantum dot structures have been proposed as an effective quantum bit (qubit) for quantum computation. A single excess electron with the freedom to move between two capacitively coupled quantum dots creates a `pseudo'-spin system with the same qubit behavior as the more natural two level system of a single electron spin. The excess electron in the double dot system is restricted to one of the two dots, thereby creating two separate and distinct states (usually referred to as |L> and |R>). The benefit of these charge qubits lie in the relative ease with which they can be manipulated and created. Experiments have been performed in this area and have shown controllable coherent oscillations and thus efficient single-qubit operations. However, the decoherence rates observed in the experiments is still quite high, making double dot charge qubits not very appealing for large-scale implementations. The following work describes the effect of the electromagnetic (EM) environment of the double quantum dot system on the decoherence of the charge state. Sources of decoherence in similar systems have been extensively investigated before and this paper follows a close theoretical framework to previous work done in the area. The effect of the EM environment can been seen in the calculations discussed below, although it is clear that the decoherence seen in experiments cannot be fully explained by the voltage fluctuations as they are investigated here. The limitations of the calculations are discussed and improvements are suggested.
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Date Issued: 2006
Identifier: CFE0001167, ucf:46850
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001167

Title: An Industrial Audiological Approach to Design and Construction of Enclosures for Control of Noise.
Creator: Smart, Dale G., Mullin, Thomas A., Social Sciences
Abstract / Description: Florida Technological University College of Social Sciences Thesis
Date Issued: 1975
Identifier: CFR0011993, ucf:53084
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0011993

Title: MAKING VISUAL NOISE.
Creator: Leitch, Deborah, Poindexter, Carla, University of Central Florida
Abstract / Description: Focusing on the combination of multi-cultural and historical influences from my personal life experiences, my creations of odd juxtapositions of space, complex pattern and new iconography in my paintings, reveal more than merely a representational image to a viewer. Although my subjects may vary from the anonymous to media celebrity, it is their relationship to me that influences the creation of my static animation and visual noise.
Date Issued: 2011
Identifier: CFE0003623, ucf:48847
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0003623

Title: Active Learning with Unreliable Annotations.
Creator: Zhao, Liyue, Sukthankar, Gita, Tappen, Marshall, Georgiopoulos, Michael, Sukthankar, Rahul, University of Central Florida
Abstract / Description: With the proliferation of social media, gathering data has became cheaper and easier than before. However, this data can not be used for supervised machine learning without labels. Asking experts to annotate sufficient data for training is both expensive and time-consuming. Current techniques provide two solutions to reducing the cost and providing sufficient labels: crowdsourcing and active learning. Crowdsourcing, which outsources tasks to a distributed group of people, can be used to...
Show moreWith the proliferation of social media, gathering data has became cheaper and easier than before. However, this data can not be used for supervised machine learning without labels. Asking experts to annotate sufficient data for training is both expensive and time-consuming. Current techniques provide two solutions to reducing the cost and providing sufficient labels: crowdsourcing and active learning. Crowdsourcing, which outsources tasks to a distributed group of people, can be used to provide a large quantity of labels but controlling the quality of labels is hard. Active learning, which requires experts to annotate a subset of the most informative or uncertain data, is very sensitive to the annotation errors. Though these two techniques can be used independently of one another, by using them in combination they can complement each other's weakness. In this thesis, I investigate the development of active learning Support Vector Machines (SVMs) and expand this model to sequential data. Then I discuss the weakness of combining active learning and crowdsourcing, since the active learning is very sensitive to low quality annotations which are unavoidable for labels collected from crowdsourcing. In this thesis, I propose three possible strategies, incremental relabeling, importance-weighted label prediction and active Bayesian Networks. The incremental relabeling strategy requires workers to devote more annotations to uncertain samples, compared to majority voting which allocates different samples the same number of labels. Importance-weighted label prediction employs an ensemble of classifiers to guide the label requests from a pool of unlabeled training data. An active learning version of Bayesian Networks is used to model the difficulty of samples and the expertise of workers simultaneously to evaluate the relative weight of workers' labels during the active learning process. All three strategies apply different techniques with the same expectation -- identifying the optimal solution for applying an active learning model with mixed label quality to crowdsourced data. However, the active Bayesian Networks model, which is the core element of this thesis, provides additional benefits by estimating the expertise of workers during the training phase. As an example application, I also demonstrate the utility of crowdsourcing for human activity recognition problems.
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Date Issued: 2013
Identifier: CFE0004965, ucf:49579
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0004965

Title: MODELING OF ATMOSPHERIC REFRACTION EFFECTS ON TRAFFIC NOISE PROPAGATION.
Creator: El-Aassar, Ahmed, Wayson, Roger, University of Central Florida
Abstract / Description: Traffic noise has been shown to have negative effects on exposed persons in the communities along highways. Noise from transportation systems is considered a nuisance in the U.S. and the government agencies require a determination of noise impacts for federally funded projects. There are several models available for assessing noise levels impacts. These models vary from simple charts to computer design models. Some computer models, i.e. Standard Method In Noise Analysis (STAMINA), the Traffic...
Show moreTraffic noise has been shown to have negative effects on exposed persons in the communities along highways. Noise from transportation systems is considered a nuisance in the U.S. and the government agencies require a determination of noise impacts for federally funded projects. There are several models available for assessing noise levels impacts. These models vary from simple charts to computer design models. Some computer models, i.e. Standard Method In Noise Analysis (STAMINA), the Traffic Noise Model (TNM) and the UCF Community Noise Model (CNM), have been used to predict geometric spreading, atmospheric absorption, diffraction, and ground impedance. However, they have largely neglected the atmospheric effects on noise propagation in their algorithms. The purpose of this research was to better understand and predict the meteorological effects on traffic noise propagation though measurements and comparison to acoustic theory. It should be noted that this represents an approach to incorporate refraction algorithms affecting outdoor noise propagation that must also work with algorithms for geometric spreading, ground effects, diffraction, and turbulence. The new empirical model for predicting atmospheric refraction shows that wind direction is a significant parameter and should be included in future modeling for atmospheric refraction. To accomplish this, the model includes a "wind shear" and "lapse rate" terms instead of wind speed and temperature as previously needed for input of the most used models. The model is an attempt to explain atmospheric refraction by including the parameters of wind direction, wind shear, and lapse rate that directly affect atmospheric refraction.
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Date Issued: 2006
Identifier: CFE0001505, ucf:47140
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001505

Title: ADVANCED CODING AND MODULATION FOR ULTRA-WIDEBAND AND IMPULSIVE NOISES.
Creator: Yang, Libo, Wei, Lei, University of Central Florida
Abstract / Description: The ever-growing demand for higher quality and faster multimedia content delivery over short distances in home environments drives the quest for higher data rates in wireless personal area networks (WPANs). One of the candidate IEEE 802.15.3a WPAN proposals support data rates up to 480 Mbps by using punctured convolutional codes with quadrature phase shift keying (QPSK) modulation for a multi-band orthogonal frequency-division multiplexing (MB-OFDM) system over ultra wideband (UWB) channels....
Show moreThe ever-growing demand for higher quality and faster multimedia content delivery over short distances in home environments drives the quest for higher data rates in wireless personal area networks (WPANs). One of the candidate IEEE 802.15.3a WPAN proposals support data rates up to 480 Mbps by using punctured convolutional codes with quadrature phase shift keying (QPSK) modulation for a multi-band orthogonal frequency-division multiplexing (MB-OFDM) system over ultra wideband (UWB) channels. In the first part of this dissertation, we combine more powerful near-Shannon-limit turbo codes with bandwidth efficient trellis coded modulation, i.e., turbo trellis coded modulation (TTCM), to further improve the data rates up to 1.2 Gbps. A modified iterative decoder for this TTCM coded MB-OFDM system is proposed and its bit error rate performance under various impulsive noises over both Gaussian and UWB channel is extensively investigated, especially in mismatched scenarios. A robust decoder which is immune to noise mismatch is provided based on comparison of impulsive noises in time domain and frequency domain. The accurate estimation of the dynamic noise model could be very difficult or impossible at the receiver, thus a significant performance degradation may occur due to noise mismatch. In the second part of this dissertation, we prove that the minimax decoder in \cite, which instead of minimizing the average bit error probability aims at minimizing the worst bit error probability, is optimal and robust to certain noise model with unknown prior probabilities in two and higher dimensions. Besides turbo codes, another kind of error correcting codes which approach the Shannon capacity is low-density parity-check (LDPC) codes. In the last part of this dissertation, we extend the density evolution method for sum-product decoding using mismatched noises. We will prove that as long as the true noise type and the estimated noise type used in the decoder are both binary-input memoryless output symmetric channels, the output from mismatched log-likelihood ratio (LLR) computation is also symmetric. We will show the Shannon capacity can be evaluated for mismatched LLR computation and it can be reduced if the mismatched LLR computation is not an one-to-one mapping function. We will derive the Shannon capacity, threshold and stable condition of LDPC codes for mismatched BIAWGN and BIL noise types. The results show that the noise variance estimation errors will not affect the Shannon capacity and stable condition, but the errors do reduce the threshold. The mismatch in noise type will only reduce Shannon capacity when LLR computation is based on BIL.
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Date Issued: 2007
Identifier: CFE0001836, ucf:47342
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001836

Title: INTERVENTIONS TO REDUCE THE EFFECTS OF NICU NOISE IN PRETERM NEONATES.
Creator: Manske, Rebecca L, D'Amato-Kubiet, Leslee, University of Central Florida
Abstract / Description: Exposure to excessive noise during a neonates stay in the neonatal intensive care unit (NICU) can create both immediate and long term health problems such as, hearing loss, neurological deficits, and sleep pattern disturbances. The use of earmuffs or earplugs to decrease the neonate's exposure to noise can create a more stable environment to facilitate improved growth and development. The purpose of this research was to examine the use of earmuffs or earplugs to reduce the impact of noise on...
Show moreExposure to excessive noise during a neonates stay in the neonatal intensive care unit (NICU) can create both immediate and long term health problems such as, hearing loss, neurological deficits, and sleep pattern disturbances. The use of earmuffs or earplugs to decrease the neonate's exposure to noise can create a more stable environment to facilitate improved growth and development. The purpose of this research was to examine the use of earmuffs or earplugs to reduce the impact of noise on neonates. A systematic review of literature was conducted using online databases including CINAHL, ERIC, Ebsco Host, Medline, and PsychINFO. The search included a combination of the following terms: 'preterm', 'neonate', 'NICU', 'noise', 'earplugs', and 'earmuffs'. Peer reviewed, articles published in the English language were examined that tested noise reduction devices in the NICU setting, hearing screening of neonates, and the effect of noise reduction interventions on physiologic changes in the preterm infant receiving care in the NICU. Results yielded 8 articles between the years of 1995 to 2017 which were synthesized for review. The results indicated that the use of earmuffs or earplugs in the NICU may offer a viable solution to reducing the effects of excessive noise on neonate's growth and development. The use of earmuffs or earplugs has been shown to positively improve vital signs, increase growth, improve physiological and motor development, and improve sleep efficiency. Further research on larger sample sizes is needed in order to validate the findings and offer substantial evidence for its use in the clinical setting.
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Date Issued: 2017
Identifier: CFH0000227, ucf:44683
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFH0000227

Title: Reduction of Lunchroom Noise and Other Behavior Using Feedback and Group Contingent Reinforcement.
Creator: LaRowe, Lottie N., Tucker, Richard, Social Sciences
Abstract / Description: Florida Technological University College of Social Sciences Thesis; Reduction of noise levels in an elementary school lunchroom was examined as a function of feedback and feedback plus reinforcement using group contingency procedures. Feedback consisted of signals from a traffic light with green indicating acceptable levels, yellow indicating slightly higher levels and red indicating unacceptable levels. Other behaviors, running, hitting, pushing and kicking, were measured incidentally....
Show moreFlorida Technological University College of Social Sciences Thesis; Reduction of noise levels in an elementary school lunchroom was examined as a function of feedback and feedback plus reinforcement using group contingency procedures. Feedback consisted of signals from a traffic light with green indicating acceptable levels, yellow indicating slightly higher levels and red indicating unacceptable levels. Other behaviors, running, hitting, pushing and kicking, were measured incidentally. Results indicate that feedback plus reinforcement was effective in reducing noise levels. Feedback alone was also effective, but to a lesser degree. No response - response relationship was found to exist between noise level and the other behaviors.
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Date Issued: 1978
Identifier: CFR0004324, ucf:52988
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0004324

Title: Effects of high speed dental drill noise on heart rate in normal hearing adult males.
Creator: Bunn, Thomas T., ,, Social Sciences
Abstract / Description: Florida Technological University College of Social Sciences Thesis
Date Issued: 1975
Identifier: CFR0008132, ucf:52961
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFR0008132

Title: Filtering Problems in Stochastic Tomography.
Creator: Gomez, Tyler, Swanson, Jason, Yong, Jiongmin, Tamasan, Alexandru, Dogariu, Aristide, University of Central Florida
Abstract / Description: Distinguishing signal from noise has always been a major goal in probabilistic analysis of data. Such is no less the case in the field of medical imaging, where both the processes of photon emission and their rate of absorption by the body behave as random variables. We explore methods by which to extricate solid conclusions from noisy data involving an X-ray transform, long the mathematical mainstay of such tools as computed axial tomography (CAT scans). Working on the assumption of having...
Show moreDistinguishing signal from noise has always been a major goal in probabilistic analysis of data. Such is no less the case in the field of medical imaging, where both the processes of photon emission and their rate of absorption by the body behave as random variables. We explore methods by which to extricate solid conclusions from noisy data involving an X-ray transform, long the mathematical mainstay of such tools as computed axial tomography (CAT scans). Working on the assumption of having some prior probabilities assigned to various states a body can be found in, we introduce and make rigorous an understanding of how to condition these into posterior probabilities by using the scan data.
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Date Issued: 2017
Identifier: CFE0006740, ucf:51839
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0006740

Title: NOISE CHARACERIZATION FOR PROPOSED UCF PHYISCAL SCIENCE BUILDING SITES.
Creator: Martinez, Jorge, Peale, Robert, University of Central Florida
Abstract / Description: Today's Advance Technology Facilities require low noise levels and increased noise monitoring. Ambient noise can interfere with the accuracy and precision of experiments and manufacturing processes. Therefore preconstruction site surveys are needed to develop strategies for mitigating noise. Vibration and low frequency electromagnetic fields are particularly detrimental for sensitive instruments, and they are also difficult to mitigate. However a large part of these costs can be avoided...
Show moreToday's Advance Technology Facilities require low noise levels and increased noise monitoring. Ambient noise can interfere with the accuracy and precision of experiments and manufacturing processes. Therefore preconstruction site surveys are needed to develop strategies for mitigating noise. Vibration and low frequency electromagnetic fields are particularly detrimental for sensitive instruments, and they are also difficult to mitigate. However a large part of these costs can be avoided or minimized if a quiet building site is selected in the first place. Accelerometers and gauss meters combined with a computer for acquisition and analysis provide a low cost method of evaluating noise levels at proposed building sites. This work examines low frequency vibration and electromagnetic fields at two proposed sites for the planned Physical Science Building at the University of Central Florida.
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Date Issued: 2006
Identifier: CFE0001507, ucf:47156
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001507

Title: URBAN INFILLING IMPACTS ON FLORIDA SOLID WASTE FACILITIES.
Creator: Nalamothu, Ravi, Reinhart, Debra, University of Central Florida
Abstract / Description: Increasing urbanization in the US is leading to development or re-development of lands adjacent to solid waste facilities and these lands are being considered for residential communities and commercial projects. Thus, the potential for nuisance complaints against the pre-existing solid waste facility operations has become an increasing reality. The objective of this study was to develop a methodology to gather scientific and quantifiable data related to potential nuisances caused by landfills...
Show moreIncreasing urbanization in the US is leading to development or re-development of lands adjacent to solid waste facilities and these lands are being considered for residential communities and commercial projects. Thus, the potential for nuisance complaints against the pre-existing solid waste facility operations has become an increasing reality. The objective of this study was to develop a methodology to gather scientific and quantifiable data related to potential nuisances caused by landfills to determine setbacks and buffer zones near landfill and transfer station operations. Appropriate recommendations for these setbacks were made from case studies conducted at two landfills in Florida. The study involved making measurements related to odor, noise, litter and dust. Impact on housing prices was also evaluated by analyzing publicly available house price data. In this study volatile organic compound (VOC) concentration was used as a surrogate measure for gaseous impacts. The mass flux of VOCs was measured on the landfills using the dynamic flux chamber method. The ultimate purpose of flux measurements was to provide input data for dispersion modeling to analyze the extent of odor impact around the landfills, which is outside the scope of this study. Ambient measurements were also made around Landfill A for validating the dispersion model. Although there are no significant health and odor impacts caused by the landfill, higher background concentration extend 1.2-1.5 km from the landfill center on the Southeast side of the landfill. Litter from the road sides around the landfills was collected and catalogued based on size and material type. Litter count per site obtained for both landfills was less than the 2001 and 2002 state-wide counts. The difference was statistically significant. Noise measurements were made at landfills during incineration and landfilling. Based on average measurements (Leq) obtained at various distances from WTE facility and landfilling activity, and considering EPA recommended noise level of 55 dB(A) for a quiet neighborhood, a set back distance of 1.6-1.9 km was recommended. Impact on house prices near the landfills was done for four landfills in Florida. Analysis showed that three out of four landfills had significantly impacted the house price within 0.6-0.8 km from the edge of the landfill. Dust measurements were made at Landfill B using particulate samplers, quantifying the dust associated with landfilling. Measured values were below National Ambient Air quality Standard (NAAQ) for PM10. Finally, recommendations were developed to mitigate some of these nuisances
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Date Issued: 2007
Identifier: CFE0001948, ucf:47444
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001948

Title: EFFECTS OF VOLUNTARY CONTROL ON PERFORMANCE RESPONSE UNDER STRESS.
Creator: Morris, Christina Shawn, Hancock, Peter A., University of Central Florida
Abstract / Description: Recent stressful environments within military and non-military domains are producing a new challenge for the lab-based study of stress on task performance, one that requires knowledge of underlying cognitive-motivational and goal orientation factors. Results of recent stress on task performance research traditionally employ metaphorical explanations (i.e., resource theory) in order to rapidly apply stimulus-response outcomes to the real world counterparts. This dissertation provides an...
Show moreRecent stressful environments within military and non-military domains are producing a new challenge for the lab-based study of stress on task performance, one that requires knowledge of underlying cognitive-motivational and goal orientation factors. Results of recent stress on task performance research traditionally employ metaphorical explanations (i.e., resource theory) in order to rapidly apply stimulus-response outcomes to the real world counterparts. This dissertation provides an alternative perspective about these metaphorical, or black box, interpretations and reveals how they may be confounded with respect to the intended real world counterpart. To examine how voluntary human control can influence traditional stress/no-stress research findings, traditional as well as exploratory paradigms were presented. Both noise and time pressure conditions produced significant differences between experimental and control groups on visual discrimination. However, when analogous cash payment-contingency conditions were employed, the traditional stress/no-stress findings were not evident. In addition, a second experiment revealed that this trend of differences (and non-differences) held consistently over 30 minutes of interrupted task performance time. This study indicates the importance of developing more diagnostic measures that include assessments of how the differences between participants' and the generalized operators' goals and motivations may alter results in stressful task environments.
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Date Issued: 2004
Identifier: CFE0000019, ucf:46134
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000019

Title: THE EFFECT OF HOT CARRIER STRESS ON LOW NOISE AMPLIFIER RADIO FREQUENCY PERFORMANCE UNDER WEAK AND STRONG INVERSION.
Creator: Shen, Lin, Yuan, Jiann, University of Central Florida
Abstract / Description: This thesis work is mainly focused on studying RF performance degradation of a low noise amplifier (LNA) circuit due to hot carrier effect (HCE) in both the weak and strong inversion regions. Since the figures of merit for the RF circuit characterization are gain, noise figure, input, and output matching, the LNA RF performance drift is evaluated in a Cadence SpectreRF simulator subject to these features. This thesis presents hot carrier induced degradation results of an LNA to show that the...
Show moreThis thesis work is mainly focused on studying RF performance degradation of a low noise amplifier (LNA) circuit due to hot carrier effect (HCE) in both the weak and strong inversion regions. Since the figures of merit for the RF circuit characterization are gain, noise figure, input, and output matching, the LNA RF performance drift is evaluated in a Cadence SpectreRF simulator subject to these features. This thesis presents hot carrier induced degradation results of an LNA to show that the HCE phenomenon is one of the serious reliability issues in the aggressively scaled RF CMOS design, especially for long-term operation of these devices. The predicted degradation from simulation results can be used design reliable CMOS RF circuits.
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Date Issued: 2006
Identifier: CFE0000952, ucf:46763
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000952

Title: APPLICATION OF ABSORPTIVE TREATMENTS ON TRAFFIC NOISE BARRIERS IN FLORIDA.
Creator: Chua, Chin Boon, Wayson, Roger, University of Central Florida
Abstract / Description: In this thesis, the parallel barrier analysis feature in the Federal Highway Administration Traffic Noise Model (FHWA TNM), which is based on RAYVERB was used to explore the effects of multiple reflections due to single and parallel barriers and the use of absorptive treatment. Database was developed from the data collected from previous research efforts was used to generate a best fit equation model that can be used as a predetermining tool to determine the magnitude of parallel barrier...
Show moreIn this thesis, the parallel barrier analysis feature in the Federal Highway Administration Traffic Noise Model (FHWA TNM), which is based on RAYVERB was used to explore the effects of multiple reflections due to single and parallel barriers and the use of absorptive treatment. Database was developed from the data collected from previous research efforts was used to generate a best fit equation model that can be used as a predetermining tool to determine the magnitude of parallel barrier insertion loss. The best fit equation model was then used to test against measured/model result and TNM prediction results for its validity. Absorptive materials were also studied such that 3 top of them were selected and recommended for Florida highway barrier use. It was found that the top three absorptive treatments for use on Florida highway barriers have been determined to be cementitous material, metal wool and glass fiber. These materials can be used to reduce the sound reflections for single and parallel barriers. The developed best fit equation model from this research is Deg = -2.17NRC - CW0.42 + 1.97eln(BH) + RH0.29 + DBB0.27; the prediction results give moderately high R2 value of 0.55 if compared to the results from database. Prediction results from best fit equation model was also found to be consistent with the results from the measure/modeled results, providing further proof of the validity of the model. However, if compared results from equation model, TNM and measured/model (measured and model compared results using ANSI method), TNM was shown to provide higher insertion loss degradation. It was found that the most effective placement of absorptive material was the pattern which covers the barrier from the bottom up; it was also found that only about 60% from the bottom of the barrier area requires covering with high NRC absorptive treatment (NRC greater than 0.8) without sacrificing insertion loss. Also, if the barrier area near the top includes an easily obtainable NRC value of 0.4, only 40% to 50% of the bottom barrier needs absorptive treatment with a higher, more expensive NRC rating. These findings can substantially reduce the cost of conventional absorptive barrier which have full coverage of high NRC absorptive treatment. This research has begun important improvements in noise barrier design, additional work can be continued to further verify all the findings in this thesis such that easier and better equation model can be developed to calculate insertion loss degradation and cheaper absorptive barrier with less absorptive material usage can be built.
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Date Issued: 2004
Identifier: CFE0000008, ucf:46127
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0000008

Title: ULTRASHORT, HIGH POWER, AND ULTRALOW NOISE MODE-LOCKED OPTICAL PULSE GENERATION USING QUANTUM-DOT SEMICONDUCTOR LASERS.
Creator: Choi, Myoung-Taek, Delfyett, Peter, University of Central Florida
Abstract / Description: This dissertation explores various aspects and potential of optical pulse generation based on active, passive, and hybrid mode-locked quantum dot semiconductor lasers with target applications such as optical interconnect and high speed signal processing. Design guidelines are developed for the single mode operation with suppressed reflection from waveguide discontinuities. The device fabrication procedure is explained, followed by characteristics of FP laser, SOA, and monolithic two-section...
Show moreThis dissertation explores various aspects and potential of optical pulse generation based on active, passive, and hybrid mode-locked quantum dot semiconductor lasers with target applications such as optical interconnect and high speed signal processing. Design guidelines are developed for the single mode operation with suppressed reflection from waveguide discontinuities. The device fabrication procedure is explained, followed by characteristics of FP laser, SOA, and monolithic two-section devices. Short pulse generation from an external cavity mode-locked QD two-section diode laser is studied. High quality, sub-picosecond (960 fs), high peak power (1.2 W) pulse trains are obtained. The sign and magnitude of pulse chirp were measured for the first time. The role of the self-phase modulation and the linewidth enhancement factor in QD mode-locked lasers is addressed. The noise performance of two-section mode-locked lasers and a SOA-based ring laser was investigated. Significant reduction of the timing jitter under hybrid mode-locked operation was achieved owing to more than one order of magnitude reduction of the linewidth in QD gain media. Ultralow phase noise performance (integrated timing jitter of a few fs at a 10 GHz repetition rate) was demonstrated from an actively mode-locked unidirectional ring laser. These results show that quantum dot mode-locked lasers are strong competitors to conventional semiconductor lasers in noise performance. Finally we demonstrated an opto-electronic oscillator (OEO) and coupled opto-electronic oscillators (COEO) which have the potential for both high purity microwave and low noise optical pulse generation. The phase noise of the COEO is measured by the photonic delay line frequency discriminator method. Based on this study we discuss the prospects of the COEO as a low noise optical pulse source.
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Date Issued: 2006
Identifier: CFE0001410, ucf:47068
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001410

Title: GATE STACK AND CHANNEL ENGINEERING:STUDY OF METAL GATES AND GERMANIUM CHANNEL DEVICES.
Creator: Todi, Ravi, Sundaram, Kalpathy, University of Central Florida
Abstract / Description: The continued scaling of device dimensions in complementary metal oxide semiconductor (CMOS) technology within the sub-100 nm region requires an alternative high dielectric constant (high-κ) oxide layer to counter high tunneling leakage currents, a metallic gate electrode to address polysilicon depletion, boron penetration and high polysilicon sheet resistance, and high mobility channel materials to boost the CMOS performance. Metal gates can also offer improved thermal and chemical...
Show moreThe continued scaling of device dimensions in complementary metal oxide semiconductor (CMOS) technology within the sub-100 nm region requires an alternative high dielectric constant (high-κ) oxide layer to counter high tunneling leakage currents, a metallic gate electrode to address polysilicon depletion, boron penetration and high polysilicon sheet resistance, and high mobility channel materials to boost the CMOS performance. Metal gates can also offer improved thermal and chemical stability, but their use requires that we improve our understanding of how the metal alloy phase, crystallographic orientation, and composition affect the electronic properties of the metal alloy-oxide interface. To replace n++ and p++ polysilicon gate electrodes and maintain scaled device performance requires metal gate electrodes with work functions within 0.2 eV of the silicon conduction and valence band edges, i.e., 5.0-5.2 and 4.1-4.3 eV, for PMOS and NMOS devices, respectively. In addition to work function and thermal/chemical stability, metal gates must be integrated into the CMOS process flow. It is the aim of this work to significantly expand our knowledge base in alloys for dual metal gates by carrying out detailed electrical and materials studies of the binary alloy systems of Ru with p-type metal Pt. Three n-type metals systems, Ru-Ta, Ru-Hf and Ru-Nb have also been partially investigated. This work also focuses on high mobility Ge p-MOSFETs for improved CMOS performance. DC magnetron sputtering has been used to deposit binary alloy films on thermally grown SiO2. The composition of the alloy films have been determined by Rutherford backscattering spectrometry and the identification of phases present have been made using x-ray and electron diffraction of samples. The microstructure of the phases of interest has been examined in the transmission electron microscope and film texture was characterized via x-ray diffraction. The electrical characterization includes basic resistivity measurements, and work function extraction. The work function has been determined from MOS capacitor and Schottky diodes. The need for electron and hole mobility enhancement and the progress in the development of high-κ gate stacks, has lead to renewed interest in Ge MOSFETs. The p-MOS mobility data for Ge channel devices have been reported. The results indicate greater than 2 x improvements in device mobility as compared to standard Si device. A low frequency noise assessment of silicon passivated Ge p-MOSFETs with a TiN/TaN/HfO2 gate stack has been made. For the first time we also report results on low frequency noise characterisation for a Ge P+- n junctions with and without Ni germanidation.
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Date Issued: 2007
Identifier: CFE0001554, ucf:47122
Format: Document (PDF)
PURL: http://purl.flvc.org/ucf/fd/CFE0001554

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