• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.810-818
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• 2021

A leakage current of ESS is classified mainly by the occurrence from a PCS(Power Conditioning System) section and an unbalanced grid current. The reason for the leakage current from the PCS section is a voltage change by IGBT (Insulated Gate Bipolar Transistor) switching and stray capacitance between the IGBT and heatsink. The leakage current caused by the grid unbalanced current flows to the ESS through the neutral line of grid-connected transformer for the ESS with a three limb iron type of Yg-wire connection. This paper proposes a mechanism for the occurrence of leakage current caused by stray capacitance, which is calculated using the heatsink formula, from the aspect of the PCS section and grid unbalance current. Based on the proposed mechanisms, this study presents the modeling of the leakage current occurrence using PSCAD/EMTDC S/W and evaluates the characteristics of leakage currents from the PCS section and grid unbalanced current. From the simulation result, the leakage current has a large influence on the battery side by confirming that the leakage current from the PCS is increased from 7[mA] to 34[mA], and the leakage current from an unbalanced load to battery housing is increased from 3.96[mA] to 10.76[mA] according to the resistance of the housings and the magnitude of the ground resistance.

• Conservation Science in Museum
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• v.25
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• pp.9-26
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• 2021

This paper describes the production methods that were originally used for an arrow bundle excavated from a Bronze Age residential area in Auraji in Jeongseon, Gangwon-do Province and the conservation treatment process that it subsequently underwent. An arrow conventionally consists of an arrowhead and a shaft. It is rare to excavate a shaft along with an arrowhead in a complete form since the shaft is made of organic materials. Notably, the arrow bundle from the Auraji site is of great significance as it shows traces of tangless stone arrowheads attached to charred shafts and offers an important case of the split end of a piece of a tree being inserted into an arrowhead. For a further examination of the characteristics of the arrows from Auraji, microscopic investigation was conducted and the type of wood used for the arrow shafts was examined. The sequence and direction of processing and the particle sizes of the grinding tools were revealed through the analysis of traces of grinding on the stone arrowheads. The shaft is presumed to have been made from a green length of three-year-old willow (Salix spp.). A curing agent with a high degree of waterproofing and reversibility was used during the on-site curing process according to demands of the surrounding environment, and a technique that the authors call the "Bridge" method was used for emergency collection of the relics. Once the bundle was transferred to the conservation treatment lab, reinforcing materials were carefully chosen as it was important not to damage the relics during the process of turning them for the repair of their reverse sides. For this purpose, artificial clay was selected since it can safely bear a load and has excellent physical properties. Finally, detached parts were rejoined, the relics and their surrounding materials were cleaned, and the bottom sides were finished with epoxy resin prior to the display of the relics at the museum.

• Journal of the Institute of Convergence Signal Processing
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• v.23 no.1
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• pp.21-27
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• 2022

Traditional automobile or 2-wheeled robot have limitations on mobility because of their mechanical structure. As traditional automobile is being replaced by electric cars, robot technology is applied to the car industry. In robotics, many researchers worked on omnidirectional mobile robot and produced lots of noticeable results. However in many of the results, specialized wheels such as Mecanum wheels are required. That imposes restrictions on robot speed and outdoor driving. We proposed a 2-wheeled modular robot that has omnidirectional mobility without using specialized wheels. In this paper, we propose a 4-wheeled omnidirectional mobile robot that consists of those two modular robots. The proposed robot adopts electric brakes to combine wheel housings and the robot body or to separate wheel housings from the robot body. Two absolute-type encoders and four incremental encoders are used to control the position of the wheel housing and velocities of the wheels. The proposed robot has omnidirectional mobility and can move fast and outdoor with normal tire wheels. We implemented the proposed robot and the feasibility and stability of the robot is verified by two separate experiments.

• Journal of Convergence for Information Technology
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• v.11 no.7
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• pp.47-56
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• 2021

This study a secondary data analysis study attempted to identify the factors influencing the successful aging of the elderly in Korea. Using the data of the 7th Aging Research Panel in 2018, 4,106 people over 65 years of age who had at least one non-living child and no missing values in the study variables were enrolled. Data were analyzed by frequency analysis, crossover analysis, independent sample t-test, and binary logistic regression analysis. The results of this study revealed that the factors affecting successful aging among elderly included age, the presence or absence of a spouse, education level, housing type, subjective health, exercise, alcohol drinking, and non-face-to-face contact frequency with non-cohabiting children, and the explanatory power of the variables was 24.1%. In order for the elderly to achieve successful aging, centering on child ties, the frequency of non-face-to-face contact, which can comfort the elderly's life and increase the satisfaction of life in a continuous relationship, is more important than having children live close and meet frequently. Based on this study, various strategies are needed for the successful aging of elderly people who are socially isolated due to concerns about COVID-19 infection.

• 한국노년학
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• v.29 no.1
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• pp.309-327
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• 2009

This research reviewed on the effect of elderly employment promotion project to their self-esteem and life satisfaction and got positive verification about the effectiveness of the project. The survey was conducted on 389 elderly people in Suncheon City. Some were participants on the project and others were not. SPSS Win 10.0 program was used for data analysis, and t-test, one-way ANOVA, correlation analysis, multiple regression were conducted. The results are as follows. First, elderly people who participated in the employment project had higher self-esteem and life satisfaction compare to those who did not participated in the project. Second, the job for elderly people had the most positive effect on elderly people to increase self-esteem and life satisfaction, and age, education background, income, family, and health were followed by. Third, participation on the employment for elderly was the highest correlation variable in self-esteem and life satisfaction, and health, education background, marriage status, residence type, living expense per month, economic status, and housing had significant correlations. Fourth, variables such as participation on job, education background, economic status, and age explained 32% of self-esteem, and 48% of life satisfaction. In order to increase self-esteem and life satisfaction of elderly people, we need to realize the importance of employment for elderly people, and promote projects that let elderly people to participate in job.

• Journal of the Korean Applied Science and Technology
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• v.39 no.6
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• pp.783-791
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• 2022

This Research is a descriptive study conducted to identify the academic stress, interpersonal relationships, and degree of adaptation to college life of nursing students who experienced COVID-19, and to identify factors influencing college life adaptation. The subjects of the research were sophomore students enrolled in 3 university nursing departments in G city. For data analysis, descriptive statistics, t-test, ANOVA, Pearson's correlation coefficient, and multiple regression analysis were analyzed. The research result showed a significant negative correlation (r=-.584, p<.001) for academic stress and college life adaptation, and a significant positive correlation (r=.505, p<.001) for interpersonal relationships and college life adaptation. The regression model to confirm the influencing factors on college life adaptation was shown to be significant (F=64.462 p<.001). Academic stress (β=-.542, p<.001), interpersonal relationships (β=.339, p<.001), and housing type (β=.199, p<.001) were found to be significant predictive factors. The explanatory power of these variables was 54.6%. Through the results of this research, it will be possible to provide basic data for developing educational programs to reduce academic stress, improve positive and smooth interpersonal relationships, and improve emotional support for college life adaptation.

• Industry Promotion Research
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• v.8 no.4
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• pp.113-122
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• 2023

This study is a research study aimed at finding out the relationship between lifestyle and life satisfaction of single youth households and the relationship between the mediating role of interpersonal relationships and the effect of parents' social and economic status regulation in the relationship between lifestyle and life satisfaction. To this end, this study conducted a self-written survey of single-person youth households across the country through an online survey institution, regardless of gender, and used a total of 501 copies out of 520 subjects for final results analysis. The data were analyzed using the SPSS 25.0 and AMOS 25.0 programs, and the applied statistical techniques included correlation analysis, confirmatory factor analysis, structural equation model analysis, multi-group analysis, and bootstrap. As a result of the study, there was a significant positive (+) correlation between lifestyle, life satisfaction, and interpersonal relationships of single youth households, and interpersonal relationships were found to have a mediating effect in the relationship between lifestyle and life satisfaction. It was found to have a significant positive (+) effect on income and income satisfaction, but the moderating effect of education, economic activity, housing ownership type, and class consciousness was not significant. Based on the results of these studies, it was intended to provide basic data for developing various community programs and institutional arrangements for single youth households.

• Food Science of Animal Resources
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• v.44 no.1
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• pp.51-73
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• 2024

This study investigated how birth weight differences in piglets affected carcass and muscle fiber properties as well as meat quality at slaughter. Within litters, piglets were grouped according to their birth weight as either normal (NBW; 1.62-1.73 kg) or low (LBW; 1.18-1.29 kg). At 5 weeks of age, NBW piglets were randomly transitioned to control (C) or isocaloric high fat diets derived from non-dairy (HF), while LBW piglets were randomly transitioned to high fat diets derived from non-dairy (HF) or dairy sources (HFHD). Piglets were reared in individual pens under standardized housing and feeding conditions. Live weight was recorded weekly, and pigs were slaughtered at 12 weeks of age. Hot carcass weights, dressing percentages, lean meat yield, and primal cut proportions were determined. The m. longissimus thoracis was collected from the right side of the carcass for measurement of physical and chemical properties of meat and muscle fiber characteristics. Results indicated that LBW pigs compensated for their live weight compared to NBW pigs at 6 weeks of age. The mean muscle fiber diameter of LBW-HFHD group is significantly higher than NBW-C and NBW-HF group, and the type I muscle fiber diameter is significantly higher than NBW-C group. Dairy fat inclusion in LBW pig diet reduced carcass back fat thickness. This increased the calculated lean meat yield to be comparable to that of NBW pigs fed a commercial diet. Incorporating dairy-sourced high-fat into LBW pigs' diets appears to be an effective strategy for producing carcasses equivalent to NBW pigs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.11
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• pp.1399-1408
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• 2007

This study was conducted to compare health and nutritional status of 45 home-living elderly people receiving free Meals on Wheels (MOW) (13 men, 32 women) and 81 low income class elderly people receiving free congregate meals (CM) (10 men, 71 women) served in Seoul. Data were obtained from questionnaires, anthropometry and interviews for the 24-hour dietary recall methods. There were no significant differences between the two groups in age and body mass index. Education level, type of housing, family type and income of the two groups also were not significantly different. In MOW, frequencies of exercise were lower while the prevalence of stroke, respiratory disease and loneliness were higher, compared with the CM. The scores of ADL, IADL and food habit of MOW were lower than those of CM. The average daily nutritional intake of both MOW and CM were as a whole under the DRI for Koreans. Energy and macro-nutrient intakes of MOW were tended to be lower than CM (except protein intakes for female). Ca, K, vitamin A, vitamin $B_1$, vitamin $B_2$, vitamin C and folate intakes of MOW were less than 50% of DRI. Percentages of subjects consuming energy less than 75% of EER and 4 nutrients intakes less than EAR were higher in MOW (42.2%) than in CM (1.2%). Our results indicated that dietary nutritional status of MOW was very poor, especially in the case of female elderly groups. For the welfare of the home-living elderly people receiving free MOW, meal service programs should be improved in quality of diet by national supports.

• Journal of Preventive Medicine and Public Health
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• v.21 no.1 s.23
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• pp.132-151
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• 1988

This study was conducted to establish the control program for preventing unfavorable health effects of nitrogen dioxide($NO_2$) exposure in homes by preparing the fundamental data for evaluation of relation-ships between $NO_2$ levels and influencing factors through measurements of indoor-outdoor $NO_2$ levels and personal $NO_2$ exposures for housewives with questionnaire survey on 172 homes in Pusan area from April to June, 1987 $NO_2$ measurements were made by using diffusion tube samplers(Palmes tube $NO_2$ sampler) for one week at 4 sites in homes ; kitchen(KIT), bedroom(BED), living room(LIV), outdoor(OUT) and near the collar of housewives(personal exposure livel, PNO). The details of questionnaire were number of household members(FAM), number of regular smokers (SMOKER), daily number of meals eaten(MEAL), type of housing units(HOUSE), location of house with distance from the heavy traffic roads as walking time(DIST), and of kitchen(KAREA), kind of cooking fuels(FUEL), cooking time of each meal(CTIME), usage of kitchen fan for cooking(FAN), type of heating facilities(HEAT) and so on of subject homes. The Obtained results were as fellows : 1) The mean $NO_2$ level was significantly higher at indoors than outdoors(p<0.01) and the kitchen $NO_2$ level was the highest with $33.7{\pm}13.6ppb$(9.5-81.5ppb). The mean personal exposure level of $NO_2$ for housewives was $20.6{\pm}8.8ppb$(3.1-46.9ppb). 2) The mean indoor $NO_2$ level was significantly higher in the group of household members above 5 than below 4(p<0.05), in detached dwellings than apartments(p<0.001), within 5 minutes of distance than over 5 minutes(p<0.001), in the group of unusing fan(p<0.001), in the group of longer cooking time(p<0.001), and it was in order of coal briquette, gas, electricity and oil by kind of cooking fuels(p<0.05). 3) Variables showing significant correlation(p<0.001) with indoor $NO_2$ level were kitchen $NO_2$ level(r=0.8677), cooking time(r=0.5921), outdoor $NO_2$ level(r=0.5192), personal $NO_2$ exposure level(r=0.4615), usage of kitchen fan(r=0.3573) and location of house(r=-0.2988) 4) As a result of multiple regression analysis, the most significant influencing variable to the kitchen $NO_2$ level was cooking time[KIT=$-0.378{\pm}11.772$(CTIME)+0.298(OUT)+3.102(FAN)], it was kitchen $NO_2$ level to the indoor $NO_2$ level[IND=6.996+0.458(KIT)+0.230(OUT)-1.127(KAREA)], and it was indoor $NO_2$ level to the personal $NO_2$ exposure level[PNO=15.562+0.729(IND)-4.542(DIST)-0.200(KIT)] 5) It was recognized that aritificial ventilation in the kitchen, suppression of unnecessary combustion and replacement of cooking fuel, as much as possible, were effective means for decreasing indoor $NO_2$ levels in homes.