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- Title
- Integration of Multidimensional Signal Detection Theory with Fuzzy Signal Detection Theory.
- Creator
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O'Connell, Maureen, Szalma, James, Hancock, Peter, Bohil, Corey, Reinerman, Lauren, University of Central Florida
- Abstract / Description
-
Signal detection theory (SDT) has proven to be a robust and useful statistical model for analyzing human performance in detection and decision making tasks. As with many models extensions have been proposed in order capture and represent the real world to a greater degree. Multidimensional Signal Detection Theory (MSDT) has had success in describing and modeling complex signals, signals that are comprised by more than one identifiable component dimension. Fuzzy Signal Detection Theory (FSDT)...
Show moreSignal detection theory (SDT) has proven to be a robust and useful statistical model for analyzing human performance in detection and decision making tasks. As with many models extensions have been proposed in order capture and represent the real world to a greater degree. Multidimensional Signal Detection Theory (MSDT) has had success in describing and modeling complex signals, signals that are comprised by more than one identifiable component dimension. Fuzzy Signal Detection Theory (FSDT) has had success in modeling and measuring human performance in cases where there exist ambiguity in the signal or response dimension characteristics, through the application of fuzzy set theory to the definition of the performance outcome categories. Multidimensional Fuzzy Signal Detection Theory (MFSDT) was developed to accommodate simultaneously both the multidimensionality of a signal and the fuzzification of outcome categories in order to integrate the two extensions. A series of three studies were performed to develop and test the theory. One study's purpose was to develop and derive multidimensional mapping functions, the aspect of MFSDT where MSDT and FSDT were integrated. Two receiver operating characteristic (ROC) studies were performed, one simulated and one empirical. The results from both ROC analysis indicated that for perceptually separable and perceptually integral complex stimuli that MFDST is a viable methodological approach to analyzing performance of signal detection tasks where there are complex signals with ambiguous signal characteristics.
Show less - Date Issued
- 2015
- Identifier
- CFE0005983, ucf:50763
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005983
- Title
- Complex-valued adaptive digital signal enhancement for applications in wireless communication systems.
- Creator
-
Liu, Ying, Mikhael, Wasfy, Batarseh, Issa, Yang, Thomas, Hunter, Matthew, Haralambous, Michael, Myers, Brent, University of Central Florida
- Abstract / Description
-
In recent decades, the wireless communication industry has attracted a great deal of research efforts to satisfy rigorous performance requirements and preserve high spectral efficiency. Along with this trend, I/Q modulation is frequently applied in modern wireless communications to develop high performance and high data rate systems. This has necessitated the need for applying efficient complex-valued signal processing techniques to highly-integrated, multi-standard receiver devices.In this...
Show moreIn recent decades, the wireless communication industry has attracted a great deal of research efforts to satisfy rigorous performance requirements and preserve high spectral efficiency. Along with this trend, I/Q modulation is frequently applied in modern wireless communications to develop high performance and high data rate systems. This has necessitated the need for applying efficient complex-valued signal processing techniques to highly-integrated, multi-standard receiver devices.In this dissertation, novel techniques for complex-valued digital signal enhancement are presented and analyzed for various applications in wireless communications. The first technique is a unified block processing approach to generate the complex-valued conjugate gradient Least Mean Square (LMS) techniques with optimal adaptations. The proposed algorithms exploit the concept of the complex conjugate gradients to find the orthogonal directions for updating the adaptive filter coefficients at each iteration. Along each orthogonal direction, the presented algorithms employ the complex Taylor series expansion to calculate time-varying convergence factors tailored for the adaptive filter coefficients. The performance of the developed technique is tested in the applications of channel estimation, channel equalization, and adaptive array beamforming. Comparing with the state of the art methods, the proposed techniques demonstrate improved performance and exhibit desirable characteristics for practical use.The second complex-valued signal processing technique is a novel Optimal Block Adaptive algorithm based on Circularity, OBA-C. The proposed OBA-C method compensates for a complex imbalanced signal by restoring its circularity. In addition, by utilizing the complex Taylor series expansion, the OBA-C method optimally updates the adaptive filter coefficients at each iteration. This algorithm can be applied to mitigate the frequency-dependent I/Q mismatch effects in analog front-end. Simulation results indicate that comparing with the existing methods, OBA-C exhibits superior convergence speed while maintaining excellent accuracy. The third technique is regarding interference rejection in communication systems. The research on both LMS and Independent Component Analysis (ICA) based techniques continues to receive significant attention in the area of interference cancellation. The performance of the LMS and ICA based approaches is studied for signals with different probabilistic distributions. Our research indicates that the ICA-based approach works better for super-Gaussian signals, while the LMS-based method is preferable for sub-Gaussian signals. Therefore, an appropriate choice of interference suppression algorithms can be made to satisfy the ever-increasing demand for better performance in modern receiver design.
Show less - Date Issued
- 2012
- Identifier
- CFE0004572, ucf:49192
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004572
- Title
- STUDY OF THE EGFR, SRC AND STAT3 PATHWAY IN PANCREATIC CANCER.
- Creator
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Jaganathan, Soumya, Turkson, James, University of Central Florida
- Abstract / Description
-
Cancer is associated with many molecular aberrations that support the malignant phenotype. In that regard, aberrant activation of epidermal growth factor receptor (EGFR), Src, and signal transducer and activator of transcription 3 (Stat3) occur concurrently in pancreatic cancer and are implicated in the disease phenotype. Notwithstanding, increasing evidence indicates that therapies that target only EGFR or Src are rather ineffective in modulating the cancer phenotype. The poor therapeutic...
Show moreCancer is associated with many molecular aberrations that support the malignant phenotype. In that regard, aberrant activation of epidermal growth factor receptor (EGFR), Src, and signal transducer and activator of transcription 3 (Stat3) occur concurrently in pancreatic cancer and are implicated in the disease phenotype. Notwithstanding, increasing evidence indicates that therapies that target only EGFR or Src are rather ineffective in modulating the cancer phenotype. The poor therapeutic outcome of the monotherapies targeting EGFR or Src may in part be due to the increased incidence of signaling cross-talks among aberrant signaling pathways in cancer. Molecular details of the signaling integration between EGFR, Src and Stat3, however, are lacking. Understanding how the aberrant EGFR, Src and Stat3 pathways are integrated in pancreatic cancer would facilitate the design of effective multiple-targeted, clinically feasible therapeutic modalities. Our study shows that in pancreatic cancer cell lines, aberrant Src activity promotes abnormal EGFR activation through the phosphorylation of the EGFR motifs, Tyr845, Tyr1068 and Tyr1086. Furthermore, aberrantly-active EGFR and Src together induce constitutive activation of Stat3 in pancreatic cancer cells. Evidence further shows that EGFR, Src and Stat3 physically associated into a heteromeric complex. Significantly, the EGFR, Src and Stat3 heteromeric complex is detectable in the nucleus and functions as a transcriptionally-active complex to induce the c-Myc gene. Of therapeutic significance, the concurrent inhibition of Stat3 and EGFR or Src promoted greater viability loss and apoptosis of pancreatic cancer cells in vitro, and induced stronger tumor growth inhibition in xenografts of human pancreatic cancer. Altogether, our studies suggest that the heteromeric EGFR, Src, and Stat3 complex may serve as an additional novel mechanism of support of the pancreatic cancer phenotype. Furthermore, our studies provide evidence that the concurrent targeting of Stat3 and EGFR or Stat3 and Src could be a more effective therapeutic approach for human pancreatic cancer.
Show less - Date Issued
- 2010
- Identifier
- CFE0003417, ucf:48383
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003417
- Title
- CROSS-MODAL EFFECTS IN TACTILE AND VISUAL SIGNALING.
- Creator
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Merlo, James, Hancock, Peter, University of Central Florida
- Abstract / Description
-
Using a wearable tactile display three experiments were conducted in which tactile messages were created emulating five standard US Army and Marine arm and hand signals for the military commands, namely: "Attention", "Halt", "Rally", "Move Out", and "Nuclear Biological or Chemical event (NBC)". Response times and accuracy rates were collected for novices responding to visual and tactile representations of these messages, which were displayed either alone or together in congruent or...
Show moreUsing a wearable tactile display three experiments were conducted in which tactile messages were created emulating five standard US Army and Marine arm and hand signals for the military commands, namely: "Attention", "Halt", "Rally", "Move Out", and "Nuclear Biological or Chemical event (NBC)". Response times and accuracy rates were collected for novices responding to visual and tactile representations of these messages, which were displayed either alone or together in congruent or incongruent combinations. Results indicated synergistic effects for concurrent, congruent message presentations showing superior response times when compared to individual presentations in either modality alone. This effect was mediated by participant strategy. Accuracy similarly improved when both the tactile and visual presentation were concurrently displayed as opposed to separately. In a low workload condition, participants could largely attend to a particular modality, with little interference from competing signals. If participants were not given instructions as to which modality to attend to, participants chose that modality which was received first. Lastly, initial learning and subsequent training of intuitive tactile signals occurred rapidly with large gains in performance in short training periods. These results confirm the promise for tactile messages to augment visual messaging in challenging and stressful environments particularly when visual messaging is maybe preferred but is not always feasible or possible.
Show less - Date Issued
- 2008
- Identifier
- CFE0002035, ucf:47598
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002035
- Title
- SAFETY EFFECTS OF TRAFFIC SIGNAL INSTALLATIONS ON STATE ROAD INTERSECTIONS IN NORTHEAST FLORIDA.
- Creator
-
LeDew, Christopher, Abdel-Aty, Mohamed, University of Central Florida
- Abstract / Description
-
The purpose of this thesis is to explore how the installations of traffic signals affect crash experience at intersections, to identify those factors which help predict crashes after a signal is installed, and to develop a crash prediction model. It is the intent of this thesis to supplement the Manual on Uniform Traffic Control Devices Signal Warrant procedure and aid the traffic engineer in the signal installation decision making process. Crash data, as well as operational and geometric...
Show moreThe purpose of this thesis is to explore how the installations of traffic signals affect crash experience at intersections, to identify those factors which help predict crashes after a signal is installed, and to develop a crash prediction model. It is the intent of this thesis to supplement the Manual on Uniform Traffic Control Devices Signal Warrant procedure and aid the traffic engineer in the signal installation decision making process. Crash data, as well as operational and geometric factors were examined for 32 state road intersections in the northeast Florida area before and after signal installation. Signal warrant studies were used as sources for traffic volumes, geometric information and crash history, before signal installation. The Florida Department of Transportation's Crash Analysis Reporting System (CARS) was used to gather crash data for the time period after signal installation. On average, the 32 intersections experienced a 12% increase in the total number of crashes and a 26% reduction in crash rate after signals were installed. The change in the number of crashes was not significant, but the rate change was significant with 90% confidence. Angle crash frequency dropped by 60% and the angle crash rate dropped by 66%, both are significant. Left-turn crashes dropped by 8% and their rate by 16%, although neither was significant. Rear-end crashes increased by 86% and the rear-end crash rate decreased by 5%. Neither of these changes was statistically significant. When crash severity was examined, it was found that the number of injury crashes increased by 64.8% and the rate by only 0.02%. Neither change was significant. Both the number of fatal crashes and the rate decreased by 100% and were significant. Property Damage Only (PDO) crashes increased by 96%, after signalization, but this change was not significant. The PDO rate, however, decreased by 46.5% and is significant. Operational factors such as AADT, turning movement counts, and speed limits; and geometric factors such as medians, turn lanes and numbers of lanes were considered to determine their effect on crashes at signalized intersections. Smaller roads, with low AADT, fewer lanes, and a rural character were found to benefit from signalization more than busier urbanized roads, in terms of crash rate reduction. The AADT, roadway cross section, number of lanes, medians, speed limit and left turn volume were all found to be important factors influencing crash rates. This thesis recommends: 1) the use of crash prediction models to supplement the MUTCD Crash Warrant, 2) the addition of a left-turn warrant to the MUTCD signal warranting procedure, and 3) development of an intersection database containing crash data as well as operational and geometric information to aid in future research.
Show less - Date Issued
- 2006
- Identifier
- CFE0001335, ucf:46972
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001335
- Title
- An Analysis of the Protected-Permitted Left Turn at Intersections with a Varying Number of Opposing Through Lanes.
- Creator
-
Navarro, Alexander, Radwan, Essam, Abou-Senna, Hatem, Abdel-Aty, Mohamed, University of Central Florida
- Abstract / Description
-
The Flashing Yellow Arrow Left Turn signal is quickly becoming prominent in Central Florida as a new method of handling left turns at traffic signals. While the concept of a protected-permitted left turn is not groundbreaking, the departure from the typical display of a five-section signal head is, for this type of operation. The signal head introduced is a four-section head with a flashing yellow arrow between the yellow and green arrows. With this signal head quickly becoming the standard,...
Show moreThe Flashing Yellow Arrow Left Turn signal is quickly becoming prominent in Central Florida as a new method of handling left turns at traffic signals. While the concept of a protected-permitted left turn is not groundbreaking, the departure from the typical display of a five-section signal head is, for this type of operation. The signal head introduced is a four-section head with a flashing yellow arrow between the yellow and green arrows. With this signal head quickly becoming the standard, there is a need to re-evaluate the operational characteristics of the left turning vehicle and advance the knowledge of the significant parameters that may affect the ability for a driver to make a left turn at a signalized intersection. With previous research into the behavioral and operational characteristics of the flashing yellow arrow conducted, there is more information becoming available about the differences between this signal and the previously accepted method of allowing left turns at an intersection. The protected-permitted signal is typically displayed at an intersection with up to two through lanes and generally a protected signal is installed when the number of through lanes increases above two unless specific criteria is met. With the advent of larger arterials and more traffic on the highway networks, the push to operate these intersections at their maximum efficiency has resulted in more of these protected-permitted signals being present at these larger intersections, including the flashing yellow arrow.The core of the research that follows is a comparative analysis of the operation and parameters that affect the left turn movement of the intersection with larger geometry to that of the smaller geometry. The significant parameters of the left turn movement were examined through means of collecting, organizing and analyzing just over 68 hours of field data. This research details the determining of the significant parameters based on the generation of a simulation model of the protected left turn using Synchro, a traffic simulation package, and regression models using field driven data to determine the significant parameters for predicting the number of left turns that can be made in the permitted phase under specific operating conditions. Intuitively, there is an expectation that a larger intersection will not allow for as many permitted lefts as a smaller intersection with all conditions remaining the same. The conclusions drawn from this analysis provide the framework to understanding the similarities and the differences that are encountered when the intersection geometry differs and help to more efficiently manage traffic at signalized intersections.The work of this field promises to enhance the operations of the left turning movement for traffic control devices. With an understanding of the statistical models generated, a broader base of knowledge is gained as to the significant parameters that affect a driver's ability to make the left turn. A discussion of the statistical differences and between the models generated from the small and large geometry intersections is critical to drive further research into standards being developed for the highway transportation network and the treatment of these large signalized intersections. The exploration of specific parameters to predict the number of permitted left turns will yield results as to if there is more to be considered with larger intersections moving forward as they become a standard sight on the roadway network.
Show less - Date Issued
- 2014
- Identifier
- CFE0005387, ucf:50440
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005387
- Title
- REGULATION OF APOPTOTIC ALKALINIZATION THROUGH PHOSPHORYLATION OF SODIUM HYDROGEN EXCHANGER VIA P38 MITOGEN ACTIVATED PROTEIN KINASE.
- Creator
-
GRENIER, AMY, KHALED, ANNETTE, University of Central Florida
- Abstract / Description
-
Regulation of intracellular pH is responsible for many cellular processes, such as metabolism, cell cycle progression, and apoptosis. Many chemotherapeutic agents work by inducing target cells to undergo apoptosis, a cell death process still poorly understood. Previous studies demonstrated that a rise in intracellular pH activated apoptotic proteins leading to cytochrome C release. This "apoptotic alkalinization" occurred upon activation of the plasma membrane protein, sodium hydrogen...
Show moreRegulation of intracellular pH is responsible for many cellular processes, such as metabolism, cell cycle progression, and apoptosis. Many chemotherapeutic agents work by inducing target cells to undergo apoptosis, a cell death process still poorly understood. Previous studies demonstrated that a rise in intracellular pH activated apoptotic proteins leading to cytochrome C release. This "apoptotic alkalinization" occurred upon activation of the plasma membrane protein, sodium hydrogen exchanger-1 (NHE1), whose activity is regulated by the stress kinase p38 MAPK. In previous studies, upon cytokine withdrawal from cytokine-dependent lymphocytes induced the activity of the p38 MAP kinase which then phosphorylated the C-terminus of NHE1. To identify the p38 MAPK phosphorylation sites on NHE1, in vitro p38 MAP kinase assays coupled to deletion analysis of NHE1 and mass spectrometry, identified four possible p38 MAPK phosphorylation sites. To establish that NHE1 causes apoptotic alkalinization and determine whether the identified phosphorylation sites on NHE1 are functionally significant, we used PCR site directed mutagenesis to mutate T717, S722, S725, and S728 on the C-terminus of NHE1. Stable NHE1 deficient cell lines, expressing wild type (WT) NHE or the four mutated sites (F4MUTNHE), were assessed for apoptotic alkalinization using the pH-sensitive fluorescent protein, destabilized YFP. Our results show that NHE1 is required for apoptotic alkalinization, since expression of WT NHE restored alkalinization in an NHE deficient cell line, and that this process requires the phosphorylation of the p38 MAPK target sites, since mutation of all four sites prevented the apoptotic alkalinization response.
Show less - Date Issued
- 2006
- Identifier
- CFE0001078, ucf:46768
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0001078
- Title
- Detection of DDH in Infants and Children Using Audible Acoustics.
- Creator
-
Hassan, Tanvir, Mansy, Hansen, Song, Sang-Eun, Kassab, Alain, University of Central Florida
- Abstract / Description
-
Detection of developmental dysplasia of the hip (DDH) in infants and children is important as it leads to permanent hip instability. Current methods for detecting DDH, such as ultrasound and x-rays, are relatively expensive and need qualified medical personnel to administer the test. Furthermore, x-ray ionizing radiation can have potential harmful effects. In the current study, an acoustic non-invasive and simple approach was investigated for detection of DDH. Different benchtop simplified...
Show moreDetection of developmental dysplasia of the hip (DDH) in infants and children is important as it leads to permanent hip instability. Current methods for detecting DDH, such as ultrasound and x-rays, are relatively expensive and need qualified medical personnel to administer the test. Furthermore, x-ray ionizing radiation can have potential harmful effects. In the current study, an acoustic non-invasive and simple approach was investigated for detection of DDH. Different benchtop simplified models and pig models were constructed and tested. Models were stimulated with band-limited white acoustic noise (10-2500 Hz) and the response of the models was measured. The power spectrum density, transfer function, and coherence were determined for different hip dysplasia levels and for normal cases. Results showed that the power spectrum density, transfer function, and coherence were affected by dysplasia occurrence. Effects appear larger for more severe dysplastic hips. This suggests that the proposed approach may have potential for DDH detection.
Show less - Date Issued
- 2019
- Identifier
- CFE0007816, ucf:52350
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007816
- Title
- Conversion and Validation of SIGART Program, a Progressive Traffic Signal Lights System Computer Model.
- Creator
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Troyan, Dennis F., McEwan, Stuart, Engineering
- Abstract / Description
-
Florida Technological University College of Engineering Thesis
- Date Issued
- 1972
- Identifier
- CFR0011995, ucf:53082
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0011995
- Title
- A microcomputer implementation of real time, continuously programmable digital filters.
- Creator
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Storma, William Edward, Simmons, Fred O., Engineering
- Abstract / Description
-
University of Central Florida College of Engineering Thesis; When a filter transfer function in s is replaced with the bilinear transform in z, t he resulting discrete model represents the original continuous model within a second order accuracy of integration. A unique set of recently discovered minimum memory algorithms that perform the bilinear transform on a continuous transfer function are implemented on an INTEL 8080 microprocessor system. Scal1ng techniques are used to frequency scale...
Show moreUniversity of Central Florida College of Engineering Thesis; When a filter transfer function in s is replaced with the bilinear transform in z, t he resulting discrete model represents the original continuous model within a second order accuracy of integration. A unique set of recently discovered minimum memory algorithms that perform the bilinear transform on a continuous transfer function are implemented on an INTEL 8080 microprocessor system. Scal1ng techniques are used to frequency scale all transfer functions to a standardized frequency. All data words are represented in a signed binary double precision format to maintain higher calculation speed and accuracy. Three test case transfer functions of different order are implemented using the bilinear transform algorithms. First, the algorithms are used to generate the three discrete models. Second, the continuous time models are driven by a step input function, generating a continuous time output. Third, the step function input is discretized and used to drive the bilinear algorithm derived models. Finally, the discrete outputs are compared with the continuous time outputs to validate and evaluate the software techniques used to implement the bilinear algorithms, which imply that the techniques provide a basis for new hardware designs.
Show less - Date Issued
- 1979
- Identifier
- CFR0003497, ucf:53140
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0003497
- Title
- A Diffraction Model for Prediction of Radar Signal Attention by a Rocket Exhaust Plume.
- Creator
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Sphar, Douglas Harrison, Mathews, B.E., Engineering
- Abstract / Description
-
Florida Technological University College of Engineering Thesis; This report documents the development of a method of estimating the signal attenuation induced by a rocket exhaust plume. The method is applicable to the early system design phase of high energy solid propellant rockets that produce highly ionized exhaust plumes. The method is based on the premise that when a plume is highly ionized, observed signal levels can be explained by assuming the signal propagates around the plume. A...
Show moreFlorida Technological University College of Engineering Thesis; This report documents the development of a method of estimating the signal attenuation induced by a rocket exhaust plume. The method is applicable to the early system design phase of high energy solid propellant rockets that produce highly ionized exhaust plumes. The method is based on the premise that when a plume is highly ionized, observed signal levels can be explained by assuming the signal propagates around the plume. A simple diffraction at a straight edge model is developed and compared to measured data. The report also provides an overview of exhaust plume electromagnetics and surveys prediction techniques.
Show less - Date Issued
- 1972
- Identifier
- CFR0003481, ucf:53035
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0003481
- Title
- The contribution of visceral fat to positive insulin signaling in Ames dwarf mice.
- Creator
-
Menon, Vinal, Masternak, Michal, Khaled, Annette, Altomare, Deborah, Estevez, Alvaro, University of Central Florida
- Abstract / Description
-
Ames dwarf (df/df) mice are homozygous for a spontaneous mutation in the prop1 gene due to which there is no development of anterior pituitary cells (-) somatotrophs, lactotrophs and thyrotrophs, leading to a deficiency of growth hormone (GH), prolactin (PRL) and thyrotropin (TSH). They tend to become obese as they age, but still live longer and healthier lives compared to their wild-type littermates, being very insulin sensitive, showing no signs of diabetes and cancer. These mutant mice...
Show moreAmes dwarf (df/df) mice are homozygous for a spontaneous mutation in the prop1 gene due to which there is no development of anterior pituitary cells (-) somatotrophs, lactotrophs and thyrotrophs, leading to a deficiency of growth hormone (GH), prolactin (PRL) and thyrotropin (TSH). They tend to become obese as they age, but still live longer and healthier lives compared to their wild-type littermates, being very insulin sensitive, showing no signs of diabetes and cancer. These mutant mice also have high circulating levels of anti-inflammatory and anti-diabetic adiponectin. Plasma levels of this adipokine usually decrease with an increase in accumulation of visceral fat (VF). We thus believe that VF in df/df mice, developed in the absence of GH signaling, may be functionally different from the same fat depots in normal (N) mice and may be beneficial, rather than detrimental, to the overall health of the animal. We performed surgeries involving removal of VF depots (epididymal and perirenal fat) in both groups of mice and hypothesize that the beneficial effects of visceral fat removal (VFR) will be present exclusively in N mice as VF in df/df mice contributes to enhanced insulin sensitivity by producing decreased levels of pro-inflammatory adipokines like TNF? and IL-6. We found that VFR improved insulin sensitivity only in N mice but not in the df/df mice. This intervention led to an upregulation of certain players of the insulin signaling pathway in the skeletal muscle of N mice only, with no alteration in df/df mice. The subcutaneous fat of df/df mice showed a downregulation of these insulin signaling genes upon VFR. Compared to N mice, epididymal fat of df/df mice (sham-operated) had increased gene expression of some of the players involved in insulin signaling and a decrease in transcript levels of TNFa. Ames dwarf mice had decreased levels of IL-6 protein in EF and in circulation. High circulating levels of adiponectin and decreased levels of IL-6 in circulation could contribute to the high insulin sensitivity observed in the Ames dwarf mice. Understanding the mechanisms responsible for VF having positive effects on insulin signaling in df/df mice would be important for future treatment of obese diabetic patients.
Show less - Date Issued
- 2013
- Identifier
- CFE0004890, ucf:49654
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004890
- Title
- BIOSIGNAL PROCESSING CHALLENGES IN EMOTION RECOGNITIONFOR ADAPTIVE LEARNING.
- Creator
-
Vartak, Aniket, Mikhael, Wasfy, University of Central Florida
- Abstract / Description
-
User-centered computer based learning is an emerging field of interdisciplinary research. Research in diverse areas such as psychology, computer science, neuroscience and signal processing is making contributions the promise to take this field to the next level. Learning systems built using contributions from these fields could be used in actual training and education instead of just laboratory proof-of-concept. One of the important advances in this research is the detection and assessment of...
Show moreUser-centered computer based learning is an emerging field of interdisciplinary research. Research in diverse areas such as psychology, computer science, neuroscience and signal processing is making contributions the promise to take this field to the next level. Learning systems built using contributions from these fields could be used in actual training and education instead of just laboratory proof-of-concept. One of the important advances in this research is the detection and assessment of the cognitive and emotional state of the learner using such systems. This capability moves development beyond the use of traditional user performance metrics to include system intelligence measures that are based on current neuroscience theories. These advances are of paramount importance in the success and wide spread use of learning systems that are automated and intelligent. Emotion is considered an important aspect of how learning occurs, and yet estimating it and making adaptive adjustments are not part of most learning systems. In this research we focus on one specific aspect of constructing an adaptive and intelligent learning system, that is, estimation of the emotion of the learner as he/she is using the automated training system. The challenge starts with the definition of the emotion and the utility of it in human life. The next challenge is to measure the co-varying factors of the emotions in a non-invasive way, and find consistent features from these measures that are valid across wide population. In this research we use four physiological sensors that are non-invasive, and establish a methodology of utilizing the data from these sensors using different signal processing tools. A validated set of visual stimuli used worldwide in the research of emotion and attention, called International Affective Picture System (IAPS), is used. A dataset is collected from the sensors in an experiment designed to elicit emotions from these validated visual stimuli. We describe a novel wavelet method to calculate hemispheric asymmetry metric using electroencephalography data. This method is tested against typically used power spectral density method. We show overall improvement in accuracy in classifying specific emotions using the novel method. We also show distinctions between different discrete emotions from the autonomic nervous system activity using electrocardiography, electrodermal activity and pupil diameter changes. Findings from different features from these sensors are used to give guidelines to use each of the individual sensors in the adaptive learning environment.
Show less - Date Issued
- 2010
- Identifier
- CFE0003301, ucf:48503
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0003301
- Title
- Sampling and Reconstruction of Spatial Signals.
- Creator
-
Cheng, Cheng, Li, Xin, Sun, Qiyu, Yong, Jiongmin, Liu, Zhe, Xu, Mengyu, University of Central Florida
- Abstract / Description
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Digital processing of signals f may start from sampling on a discrete set ?, f ?? f(?_n), ?_n ??.The sampling theory is one of the most basic and fascinating topics in applied mathematics and in engineering sciences. The most well known form is the uniform sampling theorem for band-limited/wavelet signals, that gives a framework for converting analog signals into sequences of numbers. Over the past decade, the sampling theory has undergone a strong revival and the standard sampling paradigm...
Show moreDigital processing of signals f may start from sampling on a discrete set ?, f ?? f(?_n), ?_n ??.The sampling theory is one of the most basic and fascinating topics in applied mathematics and in engineering sciences. The most well known form is the uniform sampling theorem for band-limited/wavelet signals, that gives a framework for converting analog signals into sequences of numbers. Over the past decade, the sampling theory has undergone a strong revival and the standard sampling paradigm is extended to non-bandlimited signals including signals in reproducing kernel spaces (RKSs), signals with finite rate of innovation (FRI) and sparse signals, and to nontraditional sampling methods, such as phaseless sampling.In this dissertation, we first consider the sampling and Galerkin reconstruction in a reproducing kernel space. The fidelity measure of perceptual signals, such as acoustic and visual signals, might not be well measured by least squares. In the first part of this dissertation, we introduce a fidelity measure depending on a given sampling scheme and propose a Galerkin method in Banach space setting for signal reconstruction. We show that the proposed Galerkin method provides a quasi-optimal approximation, and the corresponding Galerkin equations could be solved by an iterative approximation-projection algorithm in a reproducing kernel subspace of Lp.A spatially distributed network contains a large amount of agents with limited sensing, data processing, and communication capabilities. Recent technological advances have opened up possibilities to deploy spatially distributed networks for signal sampling and reconstruction. We introduce a graph structure for a distributed sampling and reconstruction system by coupling agents in a spatially distributed network with innovative positions of signals. We split a distributed sampling and reconstruction system into a family of overlapping smaller subsystems, and we show that the stability of the sensing matrix holds if and only if its quasi-restrictions to those subsystems have l_2 uniform stability. This new stability criterion could be pivotal for the design of a robust distributed sampling and reconstruction system against supplement, replacement and impairment of agents, as we only need to check the uniform stability of affected subsystems. We also propose an exponentially convergent distributed algorithm for signal reconstruction, that provides a suboptimal approximation to the original signal in the presence of bounded sampling noises.Phase retrieval (Phaseless Sampling and Reconstruction) arises in various fields of science and engineering. It consists of reconstructing a signal of interest from its magnitude measurements. Sampling in shift-invariant spaces is a realistic model for signals with smooth spectrum. We consider phaseless sampling and reconstruction of real-valued signals in a shift-invariant space from their magnitude measurements on the whole Euclidean space and from their phaseless samples taken on a discrete set with finite sampling density. We find an equivalence between nonseparability of signals in a shift-invariant space and their phase retrievability with phaseless samples taken on the whole Euclidean space. We also introduce an undirected graph to a signal and use connectivity of the graph to characterize the nonseparability of high-dimensional signals. Under the local complement property assumption on a shift-invariant space, we find a discrete set with finite sampling density such that signals in shift-invariant spaces, that are determined by their magnitude measurements on the whole Euclidean space, can be reconstructed in a stable way from their phaseless samples taken on that discrete set. We also propose a reconstruction algorithm which provides a suboptimal approximation to the original signal when its noisy phaseless samples are available only.
Show less - Date Issued
- 2017
- Identifier
- CFE0006726, ucf:51889
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006726
- Title
- DIGITAL SIGNAL PROCESSING TECHNIQUES FOR COHERENT OPTICAL COMMUNICATION.
- Creator
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Goldfarb, Gilad, Li, Guifang, University of Central Florida
- Abstract / Description
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Coherent detection with subsequent digital signal processing (DSP) is developed, analyzed theoretically and numerically and experimentally demonstrated in various fiber‐optic transmission scenarios. The use of DSP in conjunction with coherent detection unleashes the benefits of coherent detection which rely on the preservation of full information of the incoming field. These benefits include high receiver sensitivity, the ability to achieve high spectral‐efficiency and the use of...
Show moreCoherent detection with subsequent digital signal processing (DSP) is developed, analyzed theoretically and numerically and experimentally demonstrated in various fiber‐optic transmission scenarios. The use of DSP in conjunction with coherent detection unleashes the benefits of coherent detection which rely on the preservation of full information of the incoming field. These benefits include high receiver sensitivity, the ability to achieve high spectral‐efficiency and the use of advanced modulation formats. With the immense advancements in DSP speeds, many of the problems hindering the use of coherent detection in optical transmission systems have been eliminated. Most notably, DSP alleviates the need for hardware phase‐locking and polarization tracking, which can now be achieved in the digital domain. The complexity previously associated with coherent detection is hence significantly diminished and coherent detection is once again considered a feasible detection alternative. In this thesis, several aspects of coherent detection (with or without subsequent DSP) are addressed. Coherent detection is presented as a means to extend the dispersion limit of a duobinary signal using an analog decision‐directed phase‐lock loop. Analytical bit‐error ratio estimation for quadrature phase‐shift keying signals is derived. To validate the promise for high spectral efficiency, the orthogonal‐wavelength‐division multiplexing scheme is suggested. In this scheme the WDM channels are spaced at the symbol rate, thus achieving the spectral efficiency limit. Theory, simulation and experimental results demonstrate the feasibility of this approach. Infinite impulse response filtering is shown to be an efficient alternative to finite impulse response filtering for chromatic dispersion compensation. Theory, design considerations, simulation and experimental results relating to this topic are presented. Interaction between fiber dispersion and nonlinearity remains the last major challenge deterministic effects pose for long‐haul optical data transmission. Experimental results which demonstrate the possibility to digitally mitigate both dispersion and nonlinearity are presented. Impairment compensation is achieved using backward propagation by implementing the split‐step method. Efficient realizations of the dispersion compensation operator used in this implementation are considered. Infinite‐impulse response and wavelet‐based filtering are both investigated as a means to reduce the required computational load associated with signal backward‐propagation. Possible future research directions conclude this dissertation.
Show less - Date Issued
- 2008
- Identifier
- CFE0002384, ucf:47763
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0002384
- Title
- Method for Real-Time Signal Selection for Passive Coherent Location Systems.
- Creator
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Johnson, Nicholas, Jones, W Linwood, Gong, Xun, Mikhael, Wasfy, Rockway, John, Lichtenberg, Christopher, University of Central Florida
- Abstract / Description
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Passive coherent location (PCL) systems use signals of opportunity to perform traditional radar detection, targeting, and tracking functions. Traditionally these signals include FM radio, digital TV, GSM, and GPS because of their availability in most urban environments. A benefit of having an abundance of signals is the ability to choose which of those best meet the desired system intentions. For example, one may want to choose a digital TV signal over an FM radio signal due to its range...
Show morePassive coherent location (PCL) systems use signals of opportunity to perform traditional radar detection, targeting, and tracking functions. Traditionally these signals include FM radio, digital TV, GSM, and GPS because of their availability in most urban environments. A benefit of having an abundance of signals is the ability to choose which of those best meet the desired system intentions. For example, one may want to choose a digital TV signal over an FM radio signal due to its range resolution characteristics. This work presents a novel algorithm for characterizing commercial signals for use in a PCL system. By analyzing each signal's ambiguity function in terms of amplitude, transmitter geometry, range and Doppler resolution, and sidelobe levels, a comparative evaluation can be made to decide which signals are best suited for an intended radar function. In addition, this research shows that multiple signals can be combined in the detection process to increase the probability of detection over that of a single signal. Finally, this research investigates the geometric considerations for PCL systems in terms of bistatic radar geometry. The results show zones of linear and non-linear relationships between time delay, range, and Doppler frequency.
Show less - Date Issued
- 2017
- Identifier
- CFE0007123, ucf:51964
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007123
- Title
- Sparse signal recovery under sensing and physical hardware constraints.
- Creator
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Mardaninajafabadi, Davood, Atia, George, Mikhael, Wasfy, Vosoughi, Azadeh, Rahnavard, Nazanin, Abouraddy, Ayman, University of Central Florida
- Abstract / Description
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This dissertation focuses on information recovery under two general types of sensing constraints and hardware limitations that arise in practical data acquisition systems. We study the effects of these practical limitations in the context of signal recovery problems from interferometric measurements such as for optical mode analysis.The first constraint stems from the limited number of degrees of freedom of an information gathering system, which gives rise to highly constrained sensing...
Show moreThis dissertation focuses on information recovery under two general types of sensing constraints and hardware limitations that arise in practical data acquisition systems. We study the effects of these practical limitations in the context of signal recovery problems from interferometric measurements such as for optical mode analysis.The first constraint stems from the limited number of degrees of freedom of an information gathering system, which gives rise to highly constrained sensing structures. In contrast to prior work on compressive signal recovery which relies for the most part on introducing additional hardware components to emulate randomization, we establish performance guarantees for successful signal recovery from a reduced number of measurements even with the constrained interferometer structure obviating the need for non-native components. Also, we propose control policies to guide the collection of informative measurements given prior knowledge about the constrained sensing structure. In addition, we devise a sequential implementation with a stopping rule, shown to reduce the sample complexity for a target performance in reconstruction.The second limitation considered is due to physical hardware constraints, such as the finite spatial resolution of the used components and their finite aperture size. Such limitations introduce non-linearities in the underlying measurement model. We first develop a more accurate measurement model with structured noise representing a known non-linear function of the input signal, obtained by leveraging side information about the sampling structure. Then, we devise iterative denoising algorithms shown to enhance the quality of sparse recovery in the presence of physical constraints by iteratively estimating and eliminating the non-linear term from the measurements. We also develop a class of clipping-cognizant reconstruction algorithms for modal reconstruction from interferometric measurements that compensate for clipping effects due to the finite aperture size of the used components and show they yield significant gains over schemes oblivious to such effects.
Show less - Date Issued
- 2019
- Identifier
- CFE0007675, ucf:52467
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007675
- Title
- Life history response to infection and the potential for dishonest signals in the ground cricket, Allonemobius socius.
- Creator
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Copeland, Emily, Fedorka, Kenneth, Hoffman, Eric, Crampton, William, University of Central Florida
- Abstract / Description
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In order to maximize fitness, individuals must partition their limited resources among competing physiological processes, creating negative statistical associations between processes known as (")life-history trade-offs("). Evidence indicates that individuals tend to decrease their reproductive investment when confronted with a significant immunological challenge in order to increase investment in immune defense. This trade-off is often accompanied by a significant decrease in the sexual...
Show moreIn order to maximize fitness, individuals must partition their limited resources among competing physiological processes, creating negative statistical associations between processes known as (")life-history trade-offs("). Evidence indicates that individuals tend to decrease their reproductive investment when confronted with a significant immunological challenge in order to increase investment in immune defense. This trade-off is often accompanied by a significant decrease in the sexual signal, which provides an honest signal of the male's infection status to potential mates. However, if individual residual reproductive value is low, they may instead increase their reproductive investment to maximize reproductive success before the end of their life (a.k.a. terminal investment). Here, we investigate the potential for terminal investment in the ground cricket Allonemobius socius by inoculating males with varying dosages of an immune challenge. We predicted that both high dose and advanced male age would induce terminal investment. Furthermore, we predicted that terminally investing males would produce a dishonest signal by increasing their signaling effort. We found that upon infection We found that upon infection, young males and old males differentially alter their reproductive strategy. Young males exhibited the classic deceleration of reproductive effort. However, old males increased their calling song energetics and decreased their parental investment (nuptial gift size), suggesting that old males are dishonestly signaling their condition to the female.
Show less - Date Issued
- 2012
- Identifier
- CFE0004529, ucf:49249
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0004529
- Title
- The effects of altered traffic signs upon vehicular driving modes and consequent fuel conservation and environmental benefits, as measured by vehicular noise-imprints.
- Creator
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Pfarrer, Mark Daniel, null, null, Engineering
- Abstract / Description
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Florida Technological University College of Engineering Thesis; The hypothesis is that the recorded noise-imprints of a vehicle at an intersection can be used to identify and accurately time the driving modes of deceleration, idle, slow cruise, and acceleration. This is proven by analyzing and comparing noise-imprints of vehicles at an uncontrolled intersection marked first with a 'stop' sign, and then by a 'yield' and an experimental 'dead slow' sign. By relating the duration of each driving...
Show moreFlorida Technological University College of Engineering Thesis; The hypothesis is that the recorded noise-imprints of a vehicle at an intersection can be used to identify and accurately time the driving modes of deceleration, idle, slow cruise, and acceleration. This is proven by analyzing and comparing noise-imprints of vehicles at an uncontrolled intersection marked first with a 'stop' sign, and then by a 'yield' and an experimental 'dead slow' sign. By relating the duration of each driving mode to known relations, the overall efficiency of an intersection can be characterized. A new technique for studying various types of traffic conditions at intersections is the result. Initial noise-imprint analysis and comparison shows that a 'yield' sign is to be preferred over a 'stop' sign to decrease travel time, air pollution emissions, gasoline consumption, and wear-and-tear on the car. The experimental 'dead slow' sign is used as a demonstration of the noise-imprint technique upon an unknown situation. The efficiency of a 'dead slow' sign proved to be less than that of a 'yield' sign, but still greater than that of a 'stop' sign.
Show less - Date Issued
- 1976
- Identifier
- CFR0003525, ucf:52986
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFR0003525
- Title
- Essays on Marketing Strategies in the Context of Interdependent Consumption.
- Creator
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Talebi Ashoori, Minoo, Stock, Axel, Liu, Lin, Mao, Huifang, Caputo, Michael, University of Central Florida
- Abstract / Description
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This dissertation consists of two essays in which I study the impact of two interdependent consumerbehaviors, fairness concerns and exclusivity seeking, on a companys marketing strategiesand profits specifically in a context where it tries to expand its clientele with the objective of generatingrepeat purchases, for example by running deals on daily deal platforms. In the first essay,I examine the impact of customers fairness concerns on the profitability of a company runningpromotions on...
Show moreThis dissertation consists of two essays in which I study the impact of two interdependent consumerbehaviors, fairness concerns and exclusivity seeking, on a companys marketing strategiesand profits specifically in a context where it tries to expand its clientele with the objective of generatingrepeat purchases, for example by running deals on daily deal platforms. In the first essay,I examine the impact of customers fairness concerns on the profitability of a company runningpromotions on daily deal platforms. With the prevalence of social media and the internet, informationabout such targeted promotions can become available to all consumers including those whodid not have access to the platform and paid a full-price. Conducting a laboratory experiment,I demonstrate that knowledge about targeted promotions often leads to post-promotional fairnessconcerns among these consumers resulting in an increased tendency to switch providers. Incorporatingthe results of the experiment in a two-period game-theoretic model I analyze the impactof customers post-promotional fairness concerns on the profits of quality differentiated companieswho compete by running targeted promotions. I find that the low quality provider always suffersfrom consumers sensitivity to unfairness. Contrary, I show that the high quality provider can counterintuitivelybenefit from consumers fairness concerns as long as its quality advantage is not toolarge. Furthermore, I analyze how profits are impacted when information about the targeted dealsleaks to non-targeted customers who would have bought at the regular price. I find that, counterintuitively,competing firms profits increase with leakage. In the second essay of this dissertation, Istart with the observation that many platform members are new customers and are uncertain aboutthe quality of the companys product or service until they consume it. In such a context, I examinea high quality sellers optimal signaling strategy in a market where consumers prefer to purchase ascarce product due to desire for exclusivity or to receive a service in a non-crowded environmentdue to better experience and service delivery. Utilizing a repeat purchase signaling model I show that, consistent with prior literature, the high quality firm signals its quality by making its productscarce as well as charging a high price when consumers desire for exclusivity is high and cost ofquality is great. Contrary, I also find conditions under which the high quality firm counterintuitivelymakes its product widely available and prices it low to signal its quality. The model may inpart explain how high quality sellers market their products or services on daily deal websites.
Show less - Date Issued
- 2015
- Identifier
- CFE0005890, ucf:50855
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005890
