• Korean Journal of Audiology
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• v.23 no.3
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• pp.145-152
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• 2019

Background and Objectives: The present study aims to investigate whether the cochlear implant electrode array design affects the electrophysiological and psychophysical measures. Subjects and Methods: Eighty five ears were used as data in this retrospective study. They were divided into two groups by the electrode array design: lateral wall type (LW) and perimodiolar type (PM). The electrode site was divided into three regions (basal, medial, apical). The evoked compound action potential (ECAP) threshold, T level, C level, dynamic range (DR), and aided air conduction threshold were measured. Results: The ECAP threshold was lower for the PM than for the LW, and decreased as the electrode site was closer to the apical region. The T level was lower for the PM than for the LW, and was lower on the apical region than on the other regions. The C level on the basal region was lower for the PM than for the LW whereas the C level was lower on the apical region than on the other regions. The DRs on the apical region was greater for the PM than for the LW whereas the DR was narrower on the apical region than on the other regions. The aided air conduction threshold was not different for the electrode design and frequency. Conclusions: The current study would support the advantages of the PM over the LW in that the PM had the lower current level and greater DR, which could result in more localized neural stimulation and reduced power consumption.

• Geomechanics and Engineering
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• v.33 no.5
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• pp.477-486
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• 2023

In the studies on fault dislocation of tunnel, existing literatures are mainly focused on the problems caused by normal and reverse faults, but few on strike-slip faults. The paper aims to research the deformation and failure mechanism of a tunnel under strike-slip faulting based on a model test and test-calibrated numerical simulation. A potential faulting hazard condition is considered for a real water tunnel in central Yunnan, China. Based on the faulting hazard to tunnel, laboratory model tests were conducted with a test apparatus that specially designed for strike-slip faults. Then, to verify the results obtained from the model test, a finite element model was built. By comparison, the numerical results agree with tested ones well. The results indicated that most of the shear deformation and damage would appear within fault fracture zone. The tunnel exhibited a horizontal S-shaped deformation profile under strike-slip faulting. The side walls of the tunnel mainly experience tension and compression strain state, while the roof and floor of the tunnel would be in a shear state. Circular cracks on tunnel near fault fracture zone were more significant owing to shear effects of strike-slip faulting, while the longitudinal cracks occurred at the hanging wall.

• Journal of the Korean Society of Food Culture
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• v.25 no.2
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• pp.150-159
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• 2010

We surveyed 848 university students, $21.4{\pm}2.5$ years of age, attending university in Seoul, Kongju, Chongyang-Gun in the Chungnam province of Korea, for their use of health functional foods (HFF) and for significant variables in this use, namely demographic characteristics, health related variables, dietary variables and nutritional beliefs. The prevalence of the use of HFF was 33.6%. Among all types of HFF, nutritional supplements were taken most frequently, followed by (in order) red ginseng products, apricot extract products and ginseng products. HFF use was higher in females (p<.05), in subjects living in a dormitory (p<.05) and those from families with a relative high socioeconomic status (p<.001). Self-health concern (p<.05) and usage ratio of HFF by family (p<.001) was higher in users than in nonusers of HFF. The total score of dietary assessment was higher in users than in nonusers of HFF (p<.001), and users had a more positive point of view concerning the potential health benefits of HFF than did nonusers (p<.001). Most users took HFF when they were healthy (37.2%) or when they were sick (27.4%). They did not feel special effects through the HFF use (49.8%). Most users got the information about the specifics of HFF from family and/or relatives (55.8%). Most of users confirmed nutrition facts when they purchased the HFF (70.9%), but a considerable number of users could not understand these nutrition facts (48.1%). Users preferred vitamin C- and Ca-supplements most among vitamin mineral supplements belonged to HFF. These results show that the use of HFF is common among university students. As well, the use of HFF by students is affected by various variables. Supplementary nutritional education should be undertaken among university students, in order to give them a reasonable guideline for the use of HFF, based upon influencing factors and usage behaviors that we learned from this survey.

• Journal of the Korean Society of Food Culture
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• v.22 no.4
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• pp.441-448
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• 2007

The purpose of this study was to identify HACCP-based CCP and CP from the microbial quality assessment on the process of side dish (stir-fried dried-shrimp with garlic stems) production in the meal service operation for the elderly. Total plate counts (TPC) of fresh garlic stalks were $7.80{\times}10^{3}$ CFU/g and they were above the standard value of microbial growth potential. The TPC, Coliform and E.coli were not detected in the dried shrimps. The TPCs after rinsing and slicing the garlic stems were $2.5{\times}10^{2}$ CFU/g and $5.5{\times}10^{2}$ CFU/g, respectively. The TPC number of cook’s hand and cutting board were also exceeded the standard limit with values of $2.2{\times}10^{2}$ CFU/g and $10.0{\times}10$ CFU/g, respectively. However, the TPC, Coliform and E.coli were not detected in the other cooking instruments. The identified CCP in inspection step was fresh garlic stems and that of prepreparation step was slicing the stems after blanching. Cook’s hand and cutting board were also verified as CCP and the other steps in cooking process and utensils tested were identified as CP’s. These result’s suggest that it is important to control the microbial contamination of raw materials at purchasing step and the sanitary education program should be developed for the employees for continuous supplement of safe and sound meal service for the elderly.

• Korean Journal of Exercise Nutrition
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• v.23 no.3
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• pp.13-21
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• 2019

[Purpose] Chronic stress is a precipitating factor for depression, whereas exercise is beneficial for both the mood and cognitive process. The current study demonstrates the anti-depressive effects of regular exercise and the mechanisms linked to hippocampal neurogenesis. [Methods] Mice were subjected to 14 consecutive days of restraint, followed by 3 weeks of treadmill running, and were then subjected to behavioral tests that included the forced swimming and Y-maze tests. Protein levels were assessed using western blot analysis and newborn cells were detected using 5-bromo-2'-deoxyuridine (BrdU). [Results] Three weeks of treadmill running ameliorated the behavioral depression caused by 14 days of continuous restraint stress. The exercise regimen enhanced BrdU-labeled cells and class III β-tubulin levels in the hippocampal dentate gyrus, as well as those of thioredoxin-1 (TRX-1) and synaptosomal β2-adrenergic receptors (β2-AR) under stress. In vitro experiments involving treatment with recombinant human TRX-1 (rhTRX-1) augmented the levels of phospho-extracellular signal-regulated kinases 1 and 2 (ERK1/2), nuclear β-catenin, and proliferating cell nuclear antigens, which were previously inhibited by U0216 and FH535 (inhibitors of ERK1/2 and β-catenin/T cell factor-mediated transcription, respectively). The hippocampal neurogenesis elicited by a 7-day exercise regimen was abolished by a selective inhibitor of β2-AR, butoxamine. [Conclusion] These results suggest that TRX-1-mediated hippocampal neurogenesis by β2-AR function is a potential mechanism underlying the psychotropic effect of exercise.

• Journal of Korean Academy of Dental Administration
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• v.11 no.1
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• pp.78-88
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• 2023

This study aimed to analyze the correlation between working from home and sleep disorders among domestic workers using data from the 5th Working Environment Survey in 2017. Out of the total 30,108 wage workers, 818 employees work from home and 4,090 work in an office. A random sample of 1:5 pairs, considering gender and occupational group, was selected from these employees as the study subjects. The analysis included personal characteristics, occupational characteristics, work-from-home arrangements, and sleep disorders. Age, education, employment status, years in the workforce, weekly working hours, work-life balance, self-perceived health, depression, and anxiety were all adjusted as potential confounding variables. Conditional logistic regression analysis was conducted to examine the relationship between working from home (independent variable) and sleep disorder (dependent variable). This analysis aimed to analyze the correlation between working from home and sleep disorder. The analysis revealed that working from home was associated with sleep onset latency disorder OR=3.23 (95% CI=2.67~3.91), sleep maintenance disorder OR=3.67 (95% CI=3.02~4.45), and non-restorative sleep OR=3.01 (95% CI=2.46~3.67), which showed a statistically significant relationship with all three types of sleep disorders. Factors influencing the correlation between working from home and sleep disorders included work-life balance, social isolation, and anxiety.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.721-727
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• 2023

To prevent corruption, waste, and abuse in national governance, audit agencies are established and granted significant authority and responsibilities, including ensuring their independence. However, questions have been raised about who oversees these agencies and addresses issues or misconduct that may arise within them. In the United States, to address this oversight concern, the Inspector General Act was enacted, creating an audit community called the Inspector General Community. This community comprises various audit agencies and promotes compliance with standards and investigates potential wrongdoing by audit personnel. It fosters a culture of independence and collaboration among diverse stakeholders, such as Congress, the President, the Government Accountability Office, and agency leadership. In light of this successful approach in the United States, this research seeks to study and apply similar oversight mechanisms to audit agencies in South Korea. There is a need to develop the relationship between oversight bodies and parliament in terms of improving the efficiency and effectiveness of government operations. Accordingly, this paper studies this American case and presents efficient policy measures for the supervisory system to be applied to Korea's audit organizations. It aims to identify policy insights for effective supervision, ensuring independence, and fostering a collaborative culture within our audit institutions. Therefore, domestic interest and research on this matter are essential to enhance our audit mechanisms and achieve efficient governance.

• Smart Structures and Systems
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• v.32 no.5
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• pp.319-338
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• 2023

The study presents a new hybrid data-driven method by combining radial basis functions neural networks (RBF-NN) with the Jaya algorithm (JA) to provide effective structural health monitoring of arch dams. The novelty of this approach lies in that only one user-defined parameter is required and thus can increase its effectiveness and efficiency, as compared to other machine learning techniques that often require processing a large amount of training and testing model parameters and hyper-parameters, with high time-consuming. This approach seeks rapid damage detection in arch dams under dynamic conditions, to prevent potential disasters, by utilizing the RBF-NNN to seamlessly integrate the dynamic elastic modulus (DEM) and modal parameters (such as natural frequency and mode shape) as damage indicators. To determine the dynamic characteristics of the arch dam, the JA sequentially optimizes an objective function rooted in vibration-based data sets. Two case studies of hyperbolic concrete arch dams were carefully designed using finite element simulation to demonstrate the effectiveness of the RBF-NN model, in conjunction with the Jaya algorithm. The testing results demonstrated that the proposed methods could exhibit significant computational time-savings, while effectively detecting damage in arch dam structures with complex nonlinearities. Furthermore, despite training data contaminated with a high level of noise, the RBF-NN and JA fusion remained the robustness, with high accuracy.

• Steel and Composite Structures
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• v.49 no.5
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• pp.487-502
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• 2023

In the realm of nanotechnology, the nonlocal strain gradient theory takes center stage as it scrutinizes the behavior of spinning cantilever nanobeams and nanotubes, pivotal components supporting various mechanical movements in sport structures. The dynamics of these structures have sparked debates within the scientific community, with some contending that nonlocal cantilever models fail to predict dynamic softening, while others propose that they can indeed exhibit stiffness softening characteristics. To address these disparities, this paper investigates the dynamic response of a nonlocal cantilever cylindrical beam under the influence of external discontinuous dynamic loads. The study employs four distinct models: the Euler-Bernoulli beam model, Timoshenko beam model, higher-order beam model, and a novel higher-order tube model. These models account for the effects of functionally graded materials (FGMs) in the radial tube direction, giving rise to nanotubes with varying properties. The Hamilton principle is employed to formulate the governing differential equations and precise boundary conditions. These equations are subsequently solved using the generalized differential quadrature element technique (GDQEM). This research not only advances our understanding of the dynamic behavior of nanotubes but also reveals the intriguing phenomena of both hardening and softening in the nonlocal parameter within cantilever nanostructures. Moreover, the findings hold promise for practical applications, including drug delivery, where the controlled vibrations of nanotubes can enhance the precision and efficiency of medication transport within the human body. By exploring the multifaceted characteristics of nanotubes, this study not only contributes to the design and manufacturing of rotating nanostructures but also offers insights into their potential role in revolutionizing drug delivery systems.

• Advances in materials Research
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• v.12 no.4
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• pp.263-271
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• 2023

In this study, AA1060/Alumina composites were fabricated by combined stir casting and accumulative press bonding (APB). The APB process was repeated up to six press bonding steps at 300Ċ. As the novelty, potential dynamic polarization in 3.5Wt% NaCl solution was used to study the corrosion properties of these composites. The corrosion behavior of these samples was compared and studied with that of the annealed aluminum alloy 1060 and versus the number of APB steps. So, as a result of enhancing influence on the number of APB process, this experimental investigation showed a significant enhancement in the main electrochemical parameters and the inert character of the Alumina particles. Together with Reducing the active zones of the material surfaces could delay the corrosion process. Also, at higher number of steps, the corrosion resistance of composites improved. The sample produced after six number of steps had a low corrosion density in comparison with high corrosion density of annealed specimens. Also, the scanning electron microscopy (SEM), was used to study the corrosion surface of samples.