• Journal of the Korean Vacuum Society
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• v.11 no.2
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• pp.113-118
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• 2002

We developed engineering methods to control gas flow in a plasma reactor in order to achieve good etch depth uniformity for large area GaAs etching. Finite difference numerical method was found quite useful for simulation of gas flow distribution in the reactor for dry etching of GaAs. The experimental results in $BCl_3/N_2/SF_6/He$ ICP plasmas confirmed that the simulated data fitted very well with real data. It is noticed that a focus ring could help improve both gas flow and etch uniformity for 150 mm diameter GaAs plasma etch processing. The simulation results showed that optimization of clamp configuration could decrease gas flow uniformity as low as $\pm$ 1.5% on an 100 mm(4 inch) GaAs wafer and $\pm$ 3% for a 150 m(6 inch) wafer with the fixed reactor and electrode, respectively. Comparison between simulated gas flow uniformity and real etch depth distribution data concluded that control of gas flow distribution in the chamber would be significantly important in order or achieve excellent dry etch uniformity of large area GaAs wafers.

• Korean Journal of Community Nutrition
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• v.27 no.1
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• pp.12-26
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• 2022

Objectives: This paper aimed to provide an in-depth analysis of the factors influencing the dietary habits of male and female workers at a facility in Gwangju and their awareness of the same. Methods: A total of 32 workers were divided into eight groups based on work type, gender, and age, and focus group interviews (FGIs) were conducted. The FGIs included cognitive, behavioral, and environmental questionnaires based on dietary habits and the social cognitive theory. The interviews were analyzed by subject and sub-subject using audio recordings and transcriptions. Results: Male workers in the concerned company favored meat while female workers preferred vegetables, yet by and large, the preferences were irregular. Male workers living alone frequently ate ready meals and female workers often skipped meals. An analysis of the factors influencing the study subjects' dietary habits from the cognitive, behavioral, and environmental perspectives showed that the main factors negatively affecting their dietary habits were shiftwork, living alone, and drinking. Workers were unaware of these factors and their poor eating habits. Instead, male workers complained of poor cooking skills, while female workers complained of loneliness. Workers thus appeared to need the support of nutrition education and a counseling assistant to cope with this situation. Conclusions: The study identified the fact that the absence of nutrition education left the workers unaware of their poor eating habits. The workers would need counseling and support to help them build healthy dietary habits. It would also be necessary to focus on raising the workers' cognitive awareness of dietary habits and enhancing their behavioral ability to cope with bad eating habits through nutrition education that reflects the reality of their situation.

• Journal of the Korean Applied Science and Technology
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• v.39 no.2
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• pp.271-280
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• 2022

The purpose of this study is to investigate the concept of composition of educational service quality through two integrated research methods of open questionnaires and focus group interviews for college students majoring in beauty. Participants in the study majored in beauty at 2-year and 4-year universities nationwide. The enrolled students were set as a population, and 250 people were adopted as a random sampling method and used for the survey. The series of results are as follows. First, as a result of inductive content analysis of open questionnaires, the educational service quality of beauty majors was derived into five areas: major knowledge, educational quality, professor-student intimacy, student needs reflection, usability, curriculum composition, environmental efficiency, educational equipment, and reputation. Second, as a result of the focus group interview, inductive content analysis was more reasonably pointed out and derived in depth. As a result of this study, it is believed that it can be used as basic data for the development of measurement tools for educational service quality of beauty majors.

• Journal of Korean Academy of Rural Health Nursing
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• v.19 no.1
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• pp.55-65
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• 2024

Purpose: This study was intended to gain an in-depth understanding of and explored the experiences and meanings of participating in care services among community-dwelling older adults. Methods: A focus group interview approach was adopted. Twenty older adults were interviewed from November to December 2021 using semi-structured interview questions. The data was analyzed using thematic analysis. Results: Three main themes and seven sub-themes emerged for the elderly people living alone. One main theme was "ambivalence of elderly care services," the second was "desperate need for care services," and the third was "positive changes and expectations experienced with care services." For the elderly people living with their families, two main themes and four sub-themes were identified. One main theme was "care services met within the family system," the second was "needs for care services outside the family system." Conclusion: We aim to provide a basis for strengthening the quality of elderly community care services in the mid- to long-term and establish a system of close linkages between necessary services by understanding the needs of elderly people who live alone or with their families.

• Korean Journal of Optics and Photonics
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• v.19 no.6
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• pp.389-393
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• 2008

Enhanced reconstruction of heavy occluded objects was represented using estimation of variance in computational integral imaging. The system is analyzed to extract information of enhanced reconstruction from an elemental images set. To obtain elemental images with enhanced resolution, low focus error, and large depth of focus, synthetic aperture integral imaging (SAII) utilizing a digital camera has been adopted. The focused areas of the reconstructed image are varied with the distance of the reconstruction plane. When an occluded object is occluded heavily, an occluded object can not be reconstructed by removing the occluding object. To obtain reconstruction of the occluded object by remedying the effect of heavy occlusion, the statistical technique has been adopted.

• Korean Journal of Cognitive Science
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• v.10 no.3
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• pp.67-75
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• 1999

We investigated whether human could perceive the heading direction from the optic flow made from random dots and real images simulating the motion of the observer and objects. When an object moves across the focus of expansion(FOE) in random dot simulation. the observer perceived the focus of expansion biased toward the motion direction of the object. supporting the hypothesis that the direction repulsion is produced between the expansional and the horizontal planar motion components. With real image display observers tended to perceive one's heading direction biased toward the c center of the scene regardless of the direction and position of moving 0bcts. And it was observed that the deeper the depth of the background was the larger the judgment error was. These results suggest it is more likely that human depends on different cues than the optic flow when they perceive or judge one's heading direction in the real environment.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.105-113
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• 2021

This study is a qualitative study that conducted one-on-one in-depth interviews and focus group interviews to understand the meaning of the experience of participating in a cardio-cerebrovascular disease prevention management program using a mobile app for middle-aged female workers. The subjects of this study were 26 female workers over 50 years of age who participated in a cardio-cerebrovascular disease prevention program using a mobile app in a department store. Participating experience derived from the research result were 'Pleasure of getting to know', 'Activation of mutually friendly relations', 'health concerns take care of me ', 'Accepting an unfamiliar culture', 'Convenience as if receiving counseling anywhere. Through these results, it was shown that the mobile app improves the will to practice health behavior, and it is suggested that a standard to guarantee that the mobile app is a safe program is necessary to reduce anxiety about unfamiliar programs when installing the mobile app.

• Journal of Ecology and Environment
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• v.41 no.9
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• pp.271-280
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• 2017

Background: Soil microorganisms play key roles in nutrient cycling and are distributed throughout the soil profile. Currently, there is little information about the characteristics of the microbial communities along the soil depth because most studies focus on microorganisms inhabiting the soil surface. To better understand the functions and composition of microbial communities and the biogeochemical factors that shape them at different soil depths, we analyzed microbial activities and bacterial and fungal community composition in soils up to a 120 cm depth at a fallow field located in central Korea. To examine the vertical difference of microbial activities and community composition, ${\beta}$-1,4-glucosidase, cellobiohydrolase, ${\beta}$-1,4-xylosidase, ${\beta}$-1,4-N-acetylglucosaminidase, and acid phosphatase activities were analyzed and barcoded pyrosequencing of 16S rRNA genes (bacteria) and internal transcribed spacer region (fungi) was conducted. Results: The activity of all the soil enzymes analyzed, along with soil C concentration, declined with soil depth. For example, acid phosphatase activity was $125.9({\pm}5.7({\pm}1SE))$, $30.9({\pm}0.9)$, $15.7({\pm}0.6)$, $6.7({\pm}0.9)$, and $3.3({\pm}0.3)nmol\;g^{-1}\;h^{-1}$ at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively. Among the bacterial groups, the abundance of Proteobacteria (38.5, 23.2, 23.3, 26.1, and 17.5% at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively) and Firmicutes (12.8, 11.3, 8.6, 4.3, and 0.4% at 0-15, 15-30, 30-60, 60-90, and 90-120 cm soil depths, respectively) decreased with soil depth. On the other hand, the abundance of Ascomycota (51.2, 48.6, 65.7, 46.1, and 45.7% at 15, 30, 60, 90, and 120 cm depths, respectively), a dominant fungal group at this site, showed no clear trend along the soil profile. Conclusions: Our results show that soil C availability can determine soil enzyme activity at different soil depths and that bacterial communities have a clear trend along the soil depth at this study site. These metagenomics studies, along with other studies on microbial functions, are expected to enhance our understanding on the complexity of soil microbial communities and their relationship with biogeochemical factors.

• Earthquakes and Structures
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• v.23 no.3
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• pp.271-282
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• 2022

Seismic resisting self-centering bridge piers with high energy dissipation and negligible residual displacement after an earthquake event are focus topics of current structural engineering. The energy dissipation components of typical bridge piers are often relatively single; and exhibit a certain level of damage under earthquakes, leading to large residual displacements and low cumulative energy dissipation. In this paper, a novel socket self-centering bridge pier with a hybrid energy dissipation system is proposed. The seismic resilience of bridge piers can be improved through the rational design of annular grooves and rubber cushions. The seismic response was evaluated through the finite element method. The effects of rubber cushion thickness, annular groove depth, axial compression ratio, and lateral strength contribution ratio of rubber cushion on the seismic behavior of bridge piers are systematically studied. The results show that the annular groove depth has the greatest influence on the seismic performance of the bridge pier. Especially, the lateral strength contribution ratio of the rubber cushion mainly depends on the depth of the annular groove. The axial compression ratio has a significant effect on the ultimate bearing capacity. Finally, the seismic design method is proposed according to the influence of the above research parameters on the seismic performance of bridge piers, and the method is validated by an example. It is suggested that the range of lateral strength contribution ratio of rubber cushion is 0.028 ~ 0.053.

• Journal of Korean Society on Water Environment
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• v.36 no.5
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• pp.392-404
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• 2020

The focus of this study was to quantify the thermal stratification and analyze the relationship between the stratification structure and the tributaries to understand flow variations in the Paldang Reservoir. The vertical distribution of the temperature and density gradients, and the depth and thickness of the thermocline were quantitatively calculated using a lake physics tool (rLakeAnalyzer) and high-frequency monitoring data. Based on a density gradient of 0.2 kg/㎥/m, the thermocline was formed from mid-May to early-September 2019 and the other periods were weakly stratified or mixed. The thickness of the thermocline was developed until 4.7 m and the depth of the thermocline was formed at a depth of 3 - 6 m at the front of the Paldang Reservoir. During the formation of the thermocline, the Namhangang and Gyeongancheon tributaries with relatively high water temperature (low-density) flowed into the upper layer of the reservoir, and the Bukhangang tributary with low water temperature (high-density) mainly affected the lower layer of the reservoir. This is because the density currents were formed due to the difference in the water temperature of the tributaries. The findings of this study may be used for constructing high-frequency monitoring and quantitative data analyses of reservoirs.