• Atmosphere
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• v.27 no.3
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• pp.359-370
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• 2017

In this study, the oceanic Total Precipitable Water (TPW) retrieval algorithm at 16 km altitude of High Altitude Long Endurance Unmanned Aerial Vehicle (HALE UAV) is described. Empirical equation based on Wentz method (1995) that uses the 18.7 and 22.235 GHz channels is developed using the simulated brightness temperature and SeeBor training dataset. To do radiative simulation, Satellite Data Simulator Unit (SDSU) Radiative Transfer Model (RTM) is used. The data of 60% (523) and 40% (349) in the SeeBor training dataset are used to develop and validate the TPW retrieval algorithm, respectively. The range of coefficients for the TPW retrieval at the altitude of 3~18 km with 3 km interval were 153.69~199.87 (${\alpha}$), 54.330~58.468 (${\beta}$), and 84.519~93.484 (${\gamma}$). The bias and RMSE at each altitude were found to be about $-0.81kg\;m^{-2}$ and $2.17kg\;m^{-2}$, respectively. Correlation coefficients were more than 0.9. Radiosonde observation has been generally operated over land. To validate the accuracy of the oceanic TPW retrieval algorithm, observation data from the Korea Meteorological Administration (KMA) Gisang 1 research vessel about six clear sky cases representing spring, autumn, and summer season is used. Difference between retrieved and observed TPW at 16 km altitude were in the range of $0.53{\sim}1.87kg\;m^{-2}$, which is reasonable for most applications. Difference in TPW between retrieval and observation at each altitude (3~15 km) is also presented. Differences of TPW at altitudes more than 6 km were $0.3{\sim}1.9kg\;m^{-2}$. Retrieved TPW at 3 km altitude was smaller than upper level with a difference of $-0.25{\sim}0.75kg\;m^{-2}$ compared to the observed TPW.

• The Journal of the Korea Contents Association
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• v.14 no.11
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• pp.450-466
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• 2014

This study compared and analyzed body composition, physical fitness, and physical self-concept between gifted students in mathematics and science attending Korea Science Academy (KSA) and non-gifted students attending traditional high schools. The KSA students were 117 males who entered the school in 2009. As a control group, a total of 117 non-gifted students were randomly selected from 5 cities. The results of covariate analysis taken 2 year interval, pretest (2009) and posttest (2010), indicated that gifted students were significantly taller (p<.05) than non-gifted students, and were lower in BMI (p<.05) and PBF (p<.001). There was no significant difference in physical fitness between gifted and non-gifted students. But non-gifted students have a significantly higher self-concept in physical appearance (p<.05) and physical strength (p<.05). The internal/external frame of reference model and the Big Fish Little Pond Effect (BFLPE) theory were supported. Especially, gifted students were significantly higher (p<.01) in endurance self-concept than non-gifted students. We have discussion this result as the future research subject whether it come from the characteristics of the gifted's tenacity at high level tasks.

• Journal of Bio-Environment Control
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• v.17 no.1
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• pp.1-8
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• 2008

Four cover plants such as Phlox subulata, Glechoma hederacea var. longituba, Sedum middendorffianum and Saxifraga laciniata were evaluated to investigate the effect of companion planting on reducing soil erosion in Chinese cabbage cultivated highland. The experiment was conducted using lysimeters of $5\;m{\times}2\;m$ (length$\times$width) with 5, 15 and 30% slopes. Companion plants except Sedum middendorffianum did not interface with growth of Chinese cabbage Glechoma hederacea var. longituba and Sedum middendorffianum grew faster than Phlox subulata and Saxifraga laciniata in the early growth stage suer transplanting, resulting in fast ground covering, but the ground covering by Phlox subulata and Saxifraga laciniata was delayed because growth suppression by high air temperature during summer season. Soil erosion became severe as increasing degree of slope. Assessments of the four cover plants were conducted in relation to soil conservation characteristic of scenery, endurance to the environment stress, plant growth and weed suppression. From the assessments, Phlox subulata was superior to other intercropping crops tested for reducing soil erosion in highland cultivation of Chinese cabbage.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.175-183
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• 2016

The endurance reliability assessment of a highly complex mechanism is generally predicted by the fatigue life based on simple stress analysis. This study discusses various fatigue life assessment techniques for an automobile clutch snap ring. Finite element analyses were conducted to determine the structural stress on the snap ring. Structural stress that is insensitive in regards to the mesh size and type definition is presented in this study. The structural stress definition is consistent with elementary structural mechanics theory and provides an effective measure of a stress state that pertains to fatigue behavior of welded joints in the form of both membrane and bending components. Numerical procedures for both solid models and shell or plate element models are presented to demonstrate the mesh-size insensitivity when extracting the structural stress parameters. Conventional finite element models can be used with the structural stress calculations as a post-processing procedure. The two major implications from this research were: (a) structural stresses pertaining to fatigue behavior can be consistently calculated in a mesh-insensitive manner regardless of the types of finite element models; and (b) by comparing with the clutch snap-ring fatigue test data, we should predict the fatigue fractures of an automobile clutch snap ring using this method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.9
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• pp.708-713
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• 2013

KARI is developing a solar-electric powered HALE UAV(EAV-3). For demonstrating the technology, EAV-2H, a down-scaled version of EAV-3, is developed and after EAV-2H's initial flight test, the directional stability and control need to be improved. Thus, the vertical tail and rudder of EAV-2H are redesigned with Advanced Aircraft Analysis(AAA). Size of the rudder is increased from mean chord ratio of rudder to vertical tail, $C_r/C_v(%)=30$ to $C_r/C_v(%)=60$ and size of the vertical tail is reduced 15%. As a result, the directional control to side wind($v_1$) is improved to sideslip angle, ${\beta}(deg)=25^{\circ}$ and $v_1(m/sec)=3.54$. Also, variation of airplane side force coefficient with sideslip angle ($C_{y_{\beta}}$) and variation of airplane side force coefficient with dimensionless rate of change of yaw rate ($C_{y_r}$) are reduced 15% and 22%, respectively to minimize the effect of side wind. The empennage design of EAV-2H is verified with flight tests and applied to design of KARI's solar-electric-powered EAV-3.

• Journal of the Korean Institute of Gas
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• v.22 no.2
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• pp.59-66
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• 2018

Using hydrogen fuel is expected to be suitable as a reciprocating internal combustion engine with heightened interest in HALE(High Altitude Long Endurance) UAV(Unmanned Aerial Vehicle). Hydrogen is hightest energy density per mass so it can continue to charge for long periods of time and have positive part of the environmental effects. However, it is estimated that there is less research on hydrogen fuel engine currently applied, and many studies need to be done. Depending on the operation, there are factors that result in supercooling due to reduced radiation or reduce cooling performance due to low air density. Therefore, the experiment was to change the temperature of the cooling water and investigate the effect on engine combustions. The limitation of the stable operation range due to backfire is dominated by the excess air ratio rather than the effect of the cooling water temperature change. When the cooling water temperature increases, the volumetric efficiency decreases and the torque decreases. As the cooling water temperature decreases, the heat loss was increased and consequently the thermal efficiency was decreased.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.2
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• pp.331-346
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• 2018

In the tunnel of domestic high - speed railway, the main fire - fighting facility, fire - extinguishing passageway, is installed. However, due to the high pressure of the high - speed train, frequent breakage and maintenance are caused by strong shock and long - term vibration. In order to solve these problems, it is necessary to improve the fire door, but in Korea, it is installed by submitting a certificate by simple KS F 2296 performance test. At present, it is developed as a simple test certification by producing a real scale fireproof door without the theoretical examination in advance, so that a high cost for improvement is occurring in Korea. Therefore, through this study, structural analysis study which can preliminary structure review was carried out in order to design the refuge connection passage fire door and to improve the performance improvement. In order to secure the reliability of the result value, the official authentication test (KS F 2296) were compared.

• Journal of the Korean Applied Science and Technology
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• v.37 no.4
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• pp.794-806
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• 2020

This study was conducted in order to attain an in-depth understanding of and describe the Ego-Integrity Phenomenon of the elderly of age 65 and older. The data was collected from June 2020 to July 2020 as an in-depth interview consisting of semi-structured questions. The data was analyzed using the Colaizzi's method, one of the phenomenology methods. All interviews were recorded and transcribed for analysis. Through analysis, 309 significant statements were extracted, and 88 formulations of meaning, 53 themes, 16 theme clusters, and 5 categories were derived. The categories and the theme clusters are as such : 'reflecting on the past life with delight' ('fruitfulness over the lifetime', 'achieving through fulfilling responsibilities', 'achieved specially and gratefully'), 'Currently lonely and distressed due to the bitter old days' ('Physical health needs and psychosocial needs are not met', 'Wasn't able to make good choices for parents and children', 'Elderly life is not easy'), 'Satisfaction from enduring tough and difficult journeys in life' ('Compensated for hard work at workplace and home', 'Problem solved through endurance and overcoming', 'Living a healthy elderly life by escaping from the habits of the past'), 'Realizing the way of life as an elderly' ('Now is the best and most satisfying moment', 'Managing self in old age', 'Living passionately, though it may be late', 'Retiring from the forefront of life with an abundant heart'), 'Passing on beautifully' ('Desires toward the later years', 'Hope during the last moments', 'Appearance and emotions when death approaches'). It was observed that during the Ego-Integrity Phenomenon of the elderly, they have come to discern the meaning of life by reminiscing the regrets and difficulties of the past, and through this reminiscence, they have come to attain a positive and transcendental hope for the rest of their lives. The Ego-Integrity of the elderly appeared to be subjective, dynamic, and occurring simultaneously rather than continuously. It is recommended to develop a variety of nursing interventions while taking into consideration the age and the type of experience of the elderly.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.360-366
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• 2009

The purpose of this research was to study of the lower body obesity control with female university students, particularly has been done meridian message and aroma therapy, The data included in the remainder of this research was gathered from the experimental groups consisted of eighteen female students for tested group and compared group over 8 weeks. By the observation of tested group and compared group, we could see the measurement of thigh and calf sizing down overall, but they still show some differences depend on physical constitutions of each members who has been tested. This meant that the result could be changed by the will and persistent endurance of experimented ones Both of tested group and compared group's body mass index shrinked but still there were some exceptions, this result showed the difference of each participants' willingness as well as the age gap. We could find the reduction of Total Cholesterol, LDL, neutral fat and blood sugar in both tested group and compared group. However in case of HDL the measurement increased which means wrong method of controlling obesity can show some abnormal figures

• Nutrition Research and Practice
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• v.8 no.2
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• pp.177-182
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• 2014

BACKGROUND/OBJECTIVES: Irisin, a newly identified hormone, is associated with energy homeostasis. We investigated whether aged garlic extract (AGE) and exercise training intervention could improve body weight, insulin sensitivity, skeletal muscle fibronectin domain containing protein 5 (FNDC-5) levels, and plasma irisin in high-fat diet (HFD). MATERIALS/METHODS: Male Sprague Dawley rats were fed a ND (normal diet, n=5) or HFD (n=28) for 6 weeks. After 6 weeks, all rats were divided into 5 groups for the next 4 weeks: ND, (normal diet, n=5), HFD (high-fat diet, n=7), HFDA (high-fat diet + aged garlic extract, n=7), HFDE (high-fat diet + exercise, n=7), and HFDEA (high-fat diet + exercise + aged garlic extract, n=7). Exercise groups performed treadmill exercises for 15-60 min, 5 days/week, and AGE groups received AGE (2.86 g/kg, orally injected) for 4 weeks. RESULTS: Significant decreases in body weight were observed in the ND, HFDE, and HFDEA groups, as compared with the HFD group. Neither intervention affected the masses of the gastrocnemius muscle or liver. There were no significant differences in glucose levels across the groups. The homeostatic model assessments of insulin resistance were significantly higher in the HFD group, as compared with the ND, HFDA, HFDE, and HFDEA groups. However, skeletal muscle FNDC-5 levels and plasma irisin concentrations were unaffected by AGE or exercise in obese rats. AGE supplementation and exercise training did not affect skeletal muscle FNDC-5 or plasma irisin, which are associated with insulin sensitivity in obese rats. CONCLUSION: Our results suggest that the protection against HFD-induced increases in body fat/weight and insulin resistance that are provided by AGE supplementation and exercise training may not be mediated by the regulation of FNDC-5 or irisin.