PhD, University of Cincinnati, 2008, Medicine : Biostatistics (Environmental Health)

Allele frequency distribution (AFD) is the summarized distribution of allele frequencies of genetic loci in the studied population. AFD contains important information of population demographic history and plays a crucial in the efficient conduct of genetic association studies. Unlike the allele frequency spectrum (AFS), which is a sample level concept and has received much attention, few studies have been examined AFD due to the limitation of empirical data and computational tools. In this dissertation, we investigated AFD and its related problems relevant to genome-wide association (GWA) studies. First, we established an empirical method for estimating AFD based on observable AFS data. The method is proved to be effective and efficient. Based on data from the ‘Program for Genomic Association' (PGA) project and HapMap ENCODE project, we estimated AFD for European and African populations to be used for further analysis. We next brought up an AFD-like complex disease model which is the different from the long-debated ‘Common disease common variant” (CDCV) and “Common disease rare variant” (CDRV) model. This model is theoretically reasonable and it is compatible with observable results from human Genome-wide association (GWA) studies. Finally, we compared statistical power for common frequentist's test methods and Bayesian methods in GWA studies using the simulation strategy on our AFD and complex disease model. To avoid complicated multiple testing problem, instead of traditional power, we used ‘Rank Power' which is based on the probability of true alternative hypotheses given first N ranked hypotheses are declared to be significant. The results showed that current test methods share the similar power and the improvement of Bayesian methods in GWA studies is marginal. Results of this study further augment the analytical principles and methods involved in complex disease genetic studies and in the development of efficient designs and providing statistical solutions for (open full item for complete abstract)

Committee: Ranjan Deka PhD (Committee Chair); Ranajit Chakraborty PhD (Committee Member); Ge Zhang PhD (Committee Member); Marepalli Rao PhD (Committee Member) Subjects: Biostatistics

Master of Science in Biomedical Engineering (MSBME), Wright State University, 2019, Biomedical Engineering

Near infrared spectroscopy (NIRS) is a non-invasive technique that uses near-infrared light and hemoglobin as the contrast to characterize tissue optical properties, namely optical absorption [휇푎] and scattering [휇푠′ ]. Through this characterization, it is possible to obtain information about the tissue's oxygenated (HbO) and deoxygenated (Hb) hemoglobin concentrations and oxygen saturation which are important physiological markers for diagnosis and intervention monitoring. Many commercial devices use a continuous wave approach (CW-fNIRS), a technique that simply relies on intensity changes from a constant power laser to determine only relative changes in oxygenation. This is a significant limitation for clinical settings where there is a need for assessing absolute values of these parameters during monitoring of an intervention, lasting from weeks to months. For example, children with autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD) go through behavioral, diet and medication-based therapies that can last several months. Thus, an absolute quantitative number can be a reliable metric to assess the changes induced by these longitudinal interventions in these populations. In this respect, a frequency-domain (FD) fNIRS approach is utilized to quantify absolute optical parameters. I will show the system and methods related to FD-fNIRS. Then I will show the experimental results from tissue-mimicking phantoms, cuff ischemia tests, and verification on Autism Model Mice. The results indicate that FD-fNIRS can quantify optical parameters within 10% error and can discriminate the contrasts between mice populations. In conclusion, FD-fNIRS can be useful technique for applications that require absolute contrasts and quantitative changes in contrasts.

Committee: Ulas Sunar Ph.D. (Advisor); Keiichiro Susuki Ph.D. (Committee Member); Mary Fendley Ph.D. (Committee Member) Subjects: Biomedical Engineering; Neurosciences; Optics; Scientific Imaging

Master of Science, The Ohio State University, 2017, Genetic Counseling

Purpose: To assess the frequency of PTEN pathogenic variants in a cohort of pediatric subjects with autism spectrum disorder (ASD), intellectual disabilities (ID), and/or global developmental delays (GDD), in the presence of macrocephaly. Methods: Retrospective chart review of subjects who were evaluated through the Nationwide Children's Hospital Child Development Center between January 1, 2015 and June 30, 2016 and received a diagnosis of ASD, ID, and/or GDD, and had macrocephaly. Medical record was abstracted to determine whether PTEN gene analysis was ordered, if testing was completed, and the results of testing. Results: One hundred eight subjects who met the study criteria had PTEN genetic testing ordered during this period. Fifty-eight subjects completed PTEN genetic testing. No PTEN pathogenic variants were identified (0/58; 95% CI: 0.0-6.3). Discussion/Conclusion: This data revealed that the frequency of PTEN pathogenic variants in subjects with a diagnosis of ASD, ID, and/or GDD in the presence of macrocephaly is less than the previously reported estimate of 10% in the literature.

Committee: Dawn Allain MS, LGC (Advisor); Emily Hansen-Kiss MS, MA, LGC (Committee Member); Robert Pilarski MS, LGC; MSW (Committee Member); Karen Ratliff-Schaub MD (Committee Member) Subjects: Genetics

Master of Science in Engineering (MSEgr), Wright State University, 2011, Electrical Engineering

With more users populating the RF spectrum and hence less available contiguous bandwidth, radar and communication waveforms are slowly forced to become more efficient at using their available frequencies. Two scenarios are considered: operation in a colored interference environment and operation in discontiguous spectral bands. Unconstrained algorithms for designing transmit waveforms and receive filters are evaluated, wherein varying a convex weight trades performance between spectral flatness and side lobe levels. An empirical study provides performance bounds for constrained radar waveform designs for an instantiation of the interference spectrum. Closed-form predictions for integrated sidelobe ratio (ISLR) and peak-to-sidelobe ratio (PSLR) for radar waveforms designed to operate in discontiguous spectral bands are derived and validated against two spectrally-disjoint waveform designs. These spectrally-disjoint waveform designs must also consider constraints imposed by hardware, such as modulus and phase restrictions. In the final part of this thesis, four spectrally-disjoint waveform designs are subjected to hardware-in-the-loop tests. Experimental results are shown and compared to computer simulations.

Committee: Brian Rigling PhD (Advisor); Fred Garber PhD (Committee Member); Zhiqiang Wu PhD (Committee Member) Subjects: Electrical Engineering

Master of Science, The Ohio State University, 2012, Mathematics

The purpose of this study was to show how mathematics can be used to analyze effects on sound. Our hope is that this may inspire student interest in mathematics. We analyzed five common industry standard effects. Research data was gathered using Mathematica and GarageBand software. Three versions of each effect were used to alter pure tone sound waves of ten different frequencies using GarageBand. Then using Mathematica's Fourier command, the frequency spectrum of each altered sound wave was generated. Through observation of each set of 30 frequency spectra, the most prominent and common pure tone components were determined. For each effect, Mathematica's Fit command was used to determine a best fit model of the magnitude of each component as a function of frequency. Our models provide descriptions of the effects that are consistent with the traditional descriptions of the industry standard effects in our study. If similar research is to be conducted, our recommendation is that more versions of each effect, a wider range of input frequencies, and a higher sampling rate would produce function models that are even more consistent with traditionally accepted effect descriptions. Furthermore, an understanding of the hardware and software design used to build effects on sound is highly recommended.

Committee: Bart Snapp (Advisor); Herb Clemens (Committee Chair); James Cogdell (Committee Member) Subjects: Mathematics Education

Master of Science (MS), Ohio University, 1998, Electrical Engineering & Computer Science (Engineering and Technology)

An implementation of acquisition using transform domain/cycle code shift keying system on a multipath channel

Committee: Jeffrey Dill (Advisor) Subjects:

Master of Science (MS), Ohio University, 2004, Electrical Engineering & Computer Science (Engineering and Technology)

We provide new analytical and computer simulation results for the performance of multitone direct-sequence spread spectrum (MT-DS-SS) signaling in the presence of imperfect synchronization, modeled as frequency offset and phase noise. We investigate performance as a function of frequency offset/phase noise standard deviation, number of subcarriers and the per-subcarrier processing gain. We assume coherent detection with BPSK modulation. Comparisons between simulations and analysis show excellent agreement. Our approach offers a realistic analytical/numerical method for performance evaluation when the target error probability values are of the order of 10 −6 or lower. In addition, our method can also be easily applied to any multicarrier system with other frequency offset/phase noise models.

Committee: David Matolak (Advisor) Subjects: