• The Journal of Engineering Geology
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• v.31 no.2
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• pp.199-209
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• 2021

This paper is written to evaluate the ground stability according to the construction of Jeju 2nd airport. Sumgol is the unique characteristics of Jeju soil, which is used to evaluate the ground stability of the airport. The research contents are as follows. 1) The geotechnical characteristics for Jeju 2nd airport was analyzed, and the Sumgol and geotechnical properties were calculated based on the existing geotechnical survey data. 2) The divided sections of Jeju 2nd airport were modeled to evaluate the ground stability after determining the section (runway and airport facilities) which have the different soil and loading properties. 3) The stability and deformation ranges of the airport ground were identified through numerical analysis. The entire airport was divided into three sections to analyze the stability of Jeju 2nd airport, and calculated the stresses, settlements, and strains of each section by computer numerical analysis modeling. For modeling, the ground and load conditions were examined, also pavement conditions for each airport ground section were examined. From the analysis results of each section according to the ground conditions, the vertical settlements were analyzed as 0.11~0.18 m and the sum of effective stress and pore water pressure were 92.75~445 kPa. These results were made by taking into account the Sumgol of the bottom ground without reinforcement, also the soil strength parameters of the airport ground were reduced for computer modeling, Therefore, if proper reinforcements are applied to the ground of Jeju 2nd airport, sufficient airport ground stability can be secured.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.747-758
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• 2022

This study aimed to identify the factors that influence depression in stressed adults by age. Data were extracted from the 7th Korea National Health and Nutrition Examination Survey, covering 3,333 adults aged 20 to 59 years who were highly aware of stress. Linear regression analysis was performed using the IBM SPSS 25.0 program. The study found that in the case of people in their 20s, education level, health-related quality of life, obesity, weight change, smoking, and subjective body type were significant influencing factors, with an explanatory power of 60.3%. In the case of people in their 30s, gender, household income level, living with spouse, economic activity, health-related quality of life, food intake, obesity, alcohol consumption, smoking, and subjective health were significant influencing factors, with an explanatory power of 30.3%. For people in their 40s, household income level, living with spouse, economic activity, health-related quality of life, smoking, aerobic exercise, and subjective health were significant influencing factors, with an explanatory power of 34.4%. For people in their 50s, gender, education level, income, economic activity, health-related quality of life, protein intake, fat intake, high blood pressure, diabetes, weight control, aerobic exercise, subjective health, and subjective body type were significant influencing factors, with an explanatory power of 42.3%. Therefore, as it was found through this study that the factors affecting depression in stressed adults differ by age, it is necessary to establish an intervention strategy for each age when trying to lower depression in stressed adults.

• Journal of the Korean Applied Science and Technology
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• v.39 no.1
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• pp.96-107
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• 2022

The purpose of this study was to demonstrate the effects of 8weeks Kettlebell training on the FMS and Balance in Middle school baseball player. Fourteen middle school baseball players were randomly assigned to a kettlebell group (n=8) and a control group (n=6), and kettlebell training was applied twice a week for 60 minutes. And the FMS, Y-balance test and static and dynamic balance test using smart shoes were tested before and after kettlebell training. Repeated two-way ANOVA measures was performed both before and after the exercise to verify the effect of kettlebell training. Also, if there was an interaction between time and group, a paired sample t-test was performed for each group. As a results of the study, FMS score showed a significant difference in IL (Inline Lunge) and TS(Total Score), and there was no significant difference in other variables of FMS. The YBT score showed a significant difference in all YBT variables except for the left AT. And the balance test using smart shoes, there was no significant interaction effect between group and period in all variables. In conclusion, it was found that the application of kettlebell training in middle school baseball players had an effects on the FMS and YBT scores related to functional movement and functional balance, but it did not affect the static/dynamic balance test using smart shoes evaluated by the foot pressure method. It seems that the results of this study can be provided as basic data necessary for planning a training program for middle school baseball players.

• Journal of the Korea Society of Computer and Information
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• v.27 no.4
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• pp.99-110
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• 2022

This study attempted to develop a bodice prototype that is the basis for the production of upper body clothing for 20s plus-size women who have distinct characteristics from women with general body types. Through this, it was intended to provide basic data necessary for the development of plus-size women's clothing, which is revitalizing the market due to the increase in the obese population. Through the first evaluation of appearance and abdominal pressure, patterns such as moving the side neck, adding the amount of armhole dart, and adding the amount of sagging were modified. Through the second evaluation, corrections such as vertical side lines, reduction of the neck of the back center line, and adding the amount of armhole darts were performed. Through the third evaluation, the final pattern drafting method was developed by vertically modifying the side line and adding the amount of back armhole darts. In the case of 20s plus-size female body types, a drafting method distinguished from the general body type was required in the method of setting the side and hem due to the protrusion of the abdomen. This study can be said to be meaningful in that it proposed a bodice prototype drafting method suitable for the body type of 20s plus-size women. In the follow-up study, it is thought that the wearability should be evaluated through actual garment wearing.

• Journal of Biomedical Engineering Research
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• v.43 no.3
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• pp.136-146
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• 2022

In this study, it is intended to provide basic data that can help develop a cardiovascular simulator for performance evaluation of pulse wave detectors by identifying the development status of domestic and overseas cardiovascular simulators. A total of 119 papers were selected by excluding duplicate literature, gray literature, and literature not related to a cardiovascular simulator. Based on the selected literature, the research trend of cardiovascular simulators was analyzed. As a result of analyzing the purpose of the study, most of the simulators were developed to evaluate the hemodynamic properties of artificial hearts and valves. In addition, it was used for simulation evaluation or hemodynamic studies such as pulse wave studies. As a result of analyzing configurations of the simulators, a heart most often consisted of only one left ventricle. For blood vessels, the Windkessel model was most often constructed using chambers and valves. In most studies, blood was reproduced by mixing glycerin and water to reproduce both density and viscosity. In addition, as a result of analysis from the perspective of medical device performance evaluation, simulators for evaluating artificial heart and artificial valves have been studied a lot, whereas simulators for blood pressure, pulse wave, and blood flow devices have been relatively insignificant. Based on the review results, we suggested considerations when developing a simulator for performance evaluations of a pulse wave detector.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.5
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• pp.355-374
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• 2022

Soil conditioning improves the performance of EPB (earth pressure balance) shield TBMs (tunnel boring machines) by reducing shear strength, enhancing workability of the excavated soil, and supporting the tunnel face during EPB tunnelling. The mechanical and rheological behavior of the excavated muck mixed with additives should be properly evaluated to determine the optimal additive injection condition corresponding to each ground type. In this study, the laboratory pressurized vane test apparatus equipped with a vane-shaped rheometer was developed to reproduce the pressurized condition in the TBM chamber and quantitively evaluate rheological properties of the soil specimens. A series of the pressurized vane tests were performed for an artificial sand soil by changing foam injection ratio (FIR) and polymer injection ratio (PIR), which are the injection parameters of the foam and the polymer, respectively. In addition, the workability of the conditioned soil was evaluated through the slump test. The peak and yield stresses of the conditioned soil with respect to the injection parameters were evaluated through the rheogram, which was derived from the measured torque data in the pressurized vane test. As FIR increased or PIR decreased, the workability of the conditioned soil increased, and the maximum torque, peak stress, and yield stress decreased. The peak stress and yield stress of the specimen from the laboratory pressurized vane test correspond to the workability evaluated by the slump tests, which implies the applicability of the proposed test for evaluating the rheological properties of excavated soil.

• Geomechanics and Engineering
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• v.28 no.3
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• pp.299-311
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• 2022

Water-resisting key stratum (WKS) between coal seams is an important barrier that prevents water inrush from goaf in roof under multi-seam mining. The occurrence of water inrush can be evaluated effectively by analyzing the fracture of WKS in multi-seam mining. A "long beam" water inrush mechanical model was established using the multi-seam mining of No. 2+3 and No. 8 coal seams in Xiqu Mine as the research basis. The model comprehensively considers the pressure from goaf, the gravity of overburden rock, the gravity of accumulated water, and the constraint conditions. The stress distribution expression of the WKS was obtained under different mining distances in No. 8 coal seam. The criterion of breakage at any point of the WKS was obtained by introducing linear Mohr strength theory. By using the mechanical model, the fracture of the WKS in Xiqu Mine was examined and its breaking position was calculated. And the risk of water inrush was also evaluated. Moreover, breaking process of the WKS was reproduced with Flac3D numerical software, and was analyzed with on-site microseismic monitoring data. The results showed that when the coal face of No. 8 coal seam in Xiqu Mine advances to about 80 m ~ 100 m, the WKS is stretched and broken at the position of 60 m ~ 70 m away from the open-off cut, increasing the risk of water inrush from goaf in roof. This finding matched the result of microseismic analysis, confirming the reliability of the water inrush mechanical model. This study therefore provides a theoretical basis for the prevention of water inrush from goaf in roof in Xiqu Mine. It also provides a method for evaluating and monitoring water inrush from goaf in roof.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.107-118
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• 2022

The social need for stable hydrogen storage technologies that respond to the increasing demand for hydrogen energy is increasing. Among them, underground hydrogen storage is recognized as the most economical and reasonable storage method because of its vast hydrogen storage capacity. In Korea, low-depth hydrogen storage using artificial protective structures is being considered. Further, establishing corresponding safety standards and ground stability evaluation is becoming essential. This study evaluated the hydro-mechanical behavior of the ground during a hydrogen gas leak from a low-depth underground hydrogen storage facility through the HM coupled analysis model. The predictive reliability of the simulation model was verified through benchmark experiments. A parameter study was performed using a metamodel to analyze the sensitivity of factors affecting the surface uplift caused by the upward infiltration of high-pressure hydrogen gas. Accordingly, it was confirmed that the elastic modulus of the ground was the largest. The simulation results are considered to be valuable primary data for evaluating the complex analysis of hydrogen gas explosions as well as hydrogen gas leaks in the future.

• Korean Journal of Mineralogy and Petrology
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• v.35 no.3
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• pp.199-214
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• 2022

The Yeongnam Massif is one of representative basement provinces in the Korean Peninsula, which has experienced high-temperature, low-pressure (HTLP) regional metamorphism and partial melting. Here we reviewed recent developments in Paleoproterozoic (1.87-1.84 Ga) hot orogenesis of the Yeongnam Massif, typified by the granulite-facies metamorphism and partial melting recorded in the HTLP rocks. In particular, spatiotemporal linkage between the metamorphic and magmatic activities, including the Sancheong-Hadong anorthositic magma as a heat source, provides a key to understand the widespread HTLP metamorphism and partial melting in the Yeongnam Massif. Crustal anatexis, resulting from the fluid-present melting and muscovite/biotite dehydration melting, has yielded various types of leucosomes and leucogranites. Zircon and monazite petrochronology, using in-situ U(-Th)-Pb data from the secondary ion mass spectrometry, indicates that the HTLP metamorphism and anatexis lasted over a period of ~15 Ma at ca. 1870-1854 Ma. In addition, a fluid influx event at ca. 1840 Ma was locally recognized by the occurrence of incipient charnockite. Taken together, the Yeongnam Massif preserves a prolonged evolutionary record of the HTLP metamorphism, partial melting, and fluid influx diagnostic for a hot orogen. Such an orogen is linked to the Paleoproterozoic orogeny widespread in the North China Craton, and most likely represents the final phase of crustal evolution in the Columbia/Nuna supercontinent.

• Korean Journal of Culture and Social Issue
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• v.27 no.4
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• pp.529-559
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• 2021

This study examines how people perceive and experience busyness, which is a great social pressure in the Korean society, and The socio-psychological motives that drive people's different paces of life, such as busyness or slowness, despite being in the same busy reality, were examined. Furthermore, an in-depth study was conducted on the adaptation factors in the real society according to the speed of individual life. The analysis of this study was based on an in-depth interview data of 21 unmarried men and women in their 20s and 30s, and was conducted using a phenomenological qualitative analysis method. As a result, the perception and experience of being busy had both positive and negative parts. The components of socio-psychological motivation that affect the speed of an individual's life are 'internalization of positive values of (busy/rest)', '(future/present) centric', 'selection & concentration/Inertial busyness', 'personality characteristics' were derived. In addition, 'self-selection', 'successful time management', and 'maintenance of psychological health' were derived as common factors among adaptation factors in real society, 'a sense of achievement' and 'understanding and accepting self-characteristics' were derived as discriminatory factors. became Based on these results, the value and meaning of being busy in Korean society was discussed from a social psychology perspective, and a new perspective was presented to existing studies and discussions related to the speed of life. In addition, several follow-up studies were proposed.