Mathematical Approaches for Image Enhancement Problems

This thesis develops novel techniques that can solve some image enhancement problems using theoretically and technically proven and very useful mathematical tools to image processing such as wavelet transforms, partial differential equations, and variational models. Three subtopics are mainly covered. First, color image denoising framework is introduced to achieve high quality denoising results by considering correlations between color components while existing denoising approaches can be plugged in flexibly. Second, a new and efficient framework for image contrast and color enhancement in the compressed wavelet domain is proposed. The proposed approach is capable of enhancing both global and local contrast and brightness as well as preserving color consistency. The framework does not require inverse transform for image enhancement since linear scale factors are directly applied to both scaling and wavelet coefficients in the compressed domain, which results in high computational efficiency. Also contaminated noise in the image can be efficiently reduced by introducing wavelet shrinkage terms adaptively in different scales. The proposed method is able to enhance a wavelet-coded image computationally efficiently with high image quality and less noise or other artifact. The experimental results show that the proposed method produces encouraging results both visually and numerically compared to some existing approaches. Finally, image inpainting problem is discussed. Literature review, psychological analysis, and challenges on image inpainting problem and related topics are described. An inpainting algorithm using energy minimization and texture mapping is proposed. Mumford-Shah energy minimization model detects and preserves edges in the inpainting domain by detecting both the main structure and the detailed edges. This approach utilizes faster hierarchical level set method and guarantees convergence independent of initial conditions. The estimated segmentation results in the inpainting domain are stored in segmentation map, which is referred by a texture mapping algorithm for filling textured regions. We also propose an inpainting algorithm using wavelet transform that can expect better global structure estimation of the unknown region in addition to shape and texture properties since wavelet transforms have been used for various image analysis problems due to its nice multi-resolution properties and decoupling characteristics

Leisure Constraints to Participation in Competitive Activities and Intramural Sports: Comparing International and Domestic Students

The continuous increase in enrollment of international collegiate students into higher education highlights the importance of assessing diverse leisure opportunities that meet the needs of a diverse student population. The current study assessed the influence of leisure constraints on intramural and competitive sport participation rates between domestic and international students. A total of 273 participants were included for analysis (196 domestic students & 77 international students). International students were observed to have significantly higher intrapersonal and structural leisure constraints to participate in intramural sports, while domestic students had significantly lower leisure constraints. Implications of the study’s findings are discussed to include unique programming strategies for recreation and university administrators

Field observational constraints on the controllers in glyoxal (CHOCHO) reactive uptake to aerosol

Glyoxal (CHOCHO), the simplest dicarbonyl in the troposphere, is a potential precursor for secondary organic aerosol (SOA) and brown carbon (BrC) affecting air quality and climate. The airborne measurement of CHOCHO concentrations during the KORUS-AQ (KORea–US Air Quality study) campaign in 2016 enables detailed quantification of loss mechanisms pertaining to SOA formation in the real atmosphere. The production of this molecule was mainly from oxidation of aromatics (59 %) initiated by hydroxyl radical (OH). CHOCHO loss to aerosol was found to be the most important removal path (69 %) and contributed to roughly ∼ 20 % (3.7 µg sm−3 ppmv−1 h−1, normalized with excess CO) of SOA growth in the first 6 h in Seoul Metropolitan Area. A reactive uptake coefficient (γ) of ∼ 0.008 best represents the loss of CHOCHO by surface uptake during the campaign. To our knowledge, we show the first field observation of aerosol surface-area-dependent (Asurf) CHOCHO uptake, which diverges from the simple surface uptake assumption as Asurf increases in ambient condition. Specifically, under the low (high) aerosol loading, the CHOCHO effective uptake rate coefficient, keff,uptake, linearly increases (levels off) with Asurf; thus, the irreversible surface uptake is a reasonable (unreasonable) approximation for simulating CHOCHO loss to aerosol. Dependence on photochemical impact and changes in the chemical and physical aerosol properties “free water”, as well as aerosol viscosity, are discussed as other possible factors influencing CHOCHO uptake rate. Our inferred Henry's law coefficient of CHOCHO, 7.0×108 M atm−1, is ∼ 2 orders of magnitude higher than those estimated from salting-in effects constrained by inorganic salts only consistent with laboratory findings that show similar high partitioning into water-soluble organics, which urges more understanding on CHOCHO solubility under real atmospheric conditions

Review of machine learning methods in soft robotics

Soft robots have been extensively researched due to their flexible, deformable, and adaptive characteristics. However, compared to rigid robots, soft robots have issues in modeling, calibration, and control in that the innate characteristics of the soft materials can cause complex behaviors due to non-linearity and hysteresis. To overcome these limitations, recent studies have applied various approaches based on machine learning. This paper presents existing machine learning techniques in the soft robotic fields and categorizes the implementation of machine learning approaches in different soft robotic applications, which include soft sensors, soft actuators, and applications such as soft wearable robots. An analysis of the trends of different machine learning approaches with respect to different types of soft robot applications is presented; in addition to the current limitations in the research field, followed by a summary of the existing machine learning methods for soft robots

Image denoising using wavelet transforms

Image denoising is a fundamental process in image processing, pattern recognition, and computer vision fields. The main goal of image denoising is to enhance or restore a noisy image and help the other system (or human) to understand it better. In this thesis, we discuss some efficient approaches for image denoising using wavelet transforms. Since Donoho proposed a simple thresholding method, many different approaches have been suggested for a decade. They have shown that denoising using wavelet transforms produces superb results. This is because wavelet transform has the compaction property of having only a small number of large coefficients and a large number of small coefficients. In the first part of the thesis, some important wavelet transforms for image denoising and a literature review on the existing methods are described. In the latter part, we propose two different approaches for image denoising. The first approach is to take advantage of the higher order statistical coupling between neighbouring wavelet coefficients and their corresponding coefficients in the parent level with effective translation-invariant wavelet transforms. The other is based on multivariate statistical modeling and the clean coefficients are estimated in a general rule using Bayesian approach. Various estimation expressions can be obtained by a priori probability distribution, called multivariate generalized Gaussian distribution (MGGD). The method can take into account various related information. The experimental results show that both of our methods give comparatively higher PSNR and less visual artifact than other methods

Leisure satisfaction of sport tourists with collegiate sporting events and related local attractions

The purpose of the study was (1) to examine the frequency of travel of respondents on an overnight trip to participating in a sports event, (2) to  identify whether or not they participate in local attractions and the satisfaction levels of local attractions during the sport event and (3) to determine the effect of sport event tourism involvement and experience of local attractions on leisure satisfaction of participants by utilising the mean of the Leisure Satisfaction Scale (LSS) short form. A total of 108 participants (male=59; female=49) responded to an onsite survey near a stadium in a regional public four-year university located in the southwest region of the USA. Convenience sampling was utilised for the better understanding of fan tourists' experience of sports event participation, local attractions and their leisure satisfaction. The results revealed that the experience and  satisfaction of local attractions had a statistically significant difference in aesthetic leisure satisfaction  among six subscales of the LSS. The findings should be considered by practitioners in the development of strategies to attract more participants based on the results of leisure satisfaction levels through sport event tourism. Keywords: Aesthetic satisfaction; Collegiate sports; Leisure Satisfaction Scale; Local attractions; Sport event tourism

Effects of exercise training on health capabilities and life satisfaction among overweight and obese African American women

More importance has been placed on exercise training due to increase in the overweight and obese population. However, few studies have researched the effects of exercise training on the health capabilities and life satisfaction levels of overweight and obese African American women. This study sought to determine the effect of a 12-week exercise training on health capabilities and life satisfaction levels of overweight and obese African American women. Participants, who passed an initial screening and preassessment, were measured current health capabilities and life satisfaction levels both prior to, and following, the 12-week exercise training. The results from this study indicated an improvement in health capabilities, although with no significant differences following exercise training, while a significantly higher life satisfaction levels was observed among the overweight and obese African American women. The findings suggest that exercise training can be beneficial to enhance overweight and obese African American women’s health capabilities and life satisfaction levels. Exercise professionals should provide the appropriate exercise trainings so that overweight and obese African American women can optimize life satisfaction levels

Adolescents’ Self-Esteem Associated with Solitary, Passive, and Active Leisure Activities

Adolescents enjoy their free time in different ways including solitary, passive, and active leisure activities. The current special circumstance, the COVID-19 pandemic, provides adolescents with more free time that individuals have to spend by themselves. However, there has been little research devoted to their participation in different leisure activities and its effect on adolescent self-esteem. This study examined current adolescents’ self-esteem levels and frequency of participation among solitary, passive, and active leisure activities and how participation in different types of leisure activities affects adolescent self-esteem. A total of 1759 adolescents self-reported 13 self-esteem items and the frequency of different types of leisure activities. The results revealed that 12 items of the self-esteem scale were higher scores than the average among adolescents in this sample. Adolescents spent significantly more time on solitary leisure activity (M = 4.85) than passive (M = 2.54) and active leisure activities (M = 3.51). The results of regression indicated that solitary activities (β = 0.068, p = 0.007) and sport/exercise (β = 0.267, p < 0.001) and hanging with friends (β = 0.113, p < 0.001) of active leisure activities were positively associated with adolescent self-esteem. The findings suggest that parents, teachers, and administrators should recognize and apply appropriate directions or programs to optimize adolescents’ self-esteem by developing suitable leisure activities. It could be helpful to provide other active leisure activities such as socialized clubs or extracurricular physical activities to improve their self-esteem

Comparison of passive and active leisure activities and life satisfaction with aging

Aim: Many older adults face limitations to participating in active leisure activities as a result of their physical constraints from aging. Passive leisure activities become alternative leisure activities for older adults as a result of limited physical capacity. The present study sought to determine whether there exists a difference in the frequency of participation in passive and active leisure activities, and the effect of participation in passive and active leisure activities on the life satisfaction level of old adults. Methods: A total of 460 participants aged 60–95 years were randomly selected from 21 sites in the USA. The Life Satisfaction Index – Z and the Meaningful Activity Participation Assessment were analyzed to examine older adults\u27 life satisfaction and frequency of active or passive activities. Results: The results showed that participation in passive leisure activities, such reading, talking on the telephone and watching TV/listening to the radio, is more frequent among older adults (P = 0.000). The regression coefficient found that club/organization or volunteering (P = 0.008), homemaking/maintenance (P = 0.017) and traveling (P = 0.017) for active leisure activities were statistically significant predictors of Life Satisfaction Index – Z for older adults. Conclusions: The current study shows that older adults spent much more times participating in passive leisure activities, such as radio/watching TV, talking on the phone and reading. The result also showed that active leisure activities, such as club/organization or volunteering, home making/maintenance and traveling, were significant predictors of life satisfaction for older adults controlling for covariates. The current study suggests marketing and programming plans to overcome the constraints that influence older adults\u27 life satisfaction. Geriatr Gerontol Int 2018; 18: 380–386

Predicting Disparity between ASF-Managed Areas and Wild Boar Habitats: A Case of South Korea

African swine fever (ASF) is a highly contagious viral disease affecting both domestic and wild boars. Since its first outbreak in South Korea in 2019, substantial efforts have been made to prevent ASF transmission by reducing the wild boar population and eliminating infected carcasses; however, the persistence of ASF transmission has posed challenges to these efforts. To improve ASF management strategies, the limitations of current management strategies must be identified by considering disparities between wild boar habitats and ASF-managed areas with environmental and anthropogenic characteristics of wild boars and their management strategies. Here, ensemble species distribution models were used to estimate wild boar habitats and potential ASF-managed areas, with elevation, distance to urban areas, and Normalized Difference Vegetation Index as important variables. Binary maps of wild boar habitats and potential ASF-managed areas were generated using the maxSSS as the threshold criterion. Disparity areas of ASF management were identified by overlying regions evaluated as wild boar habitats with those not classified as ASF-managed areas. Dense forests near urban regions like Chungcheongbuk-do, Gyeongsangbuk-do, and Gyeongsangnam-do were evaluated as disparity areas having high risk of ASF transmission. These findings hold significant potential for refining ASF management strategies and establishing proactive control measures