• Journal of Astronomy and Space Sciences
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• v.19 no.4
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• pp.305-318
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• 2002

We have constructed two flight models of airglow photometer system (AGP) to be onboard Korea Sounding Rocket-III (KSR-III) for detection of MUV dayglow above the Korean peninsular. The AGP system is designed to detect dayglow emissions of OI 2972${\AA}$, $N_2$ VK(0,6) 2780${\AA}$, $N_2$ 2PG 3150${\AA}$ and background 3070${\AA}$ toward the horizon at altitudes between 100 km and 300 km. The AGP system consists of a photometer body, a baffle an electronic control unit and a battery unit. The MUV dayglow emissions enter through a narrow band interference filter and focusing lens of the photometer, which contains an ultraviolet sensitive photomultiplier tube. The photometer is equipped with an in-flight calibration light source on a circular plane that will rotate at the rocket's apogee. A bane tube is installed at the entry of the photometer in order to block strong scattering lights from the lower atmosphere. We have carried out laboratory measurements of sensitivity and in-flight calibration light source for the AGP flight models. Although absolute sensitivities of the AGP flight models could not be determined in the country, relative sensitivities among channels are well measured so that observation data during rocket flight in the future can be analyzed with confidence.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.9-17
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• 2013

This paper describes an experimental program to investigate the shear behavior of insulated concrete sandwich panels (CSPs) with different types of GFRP shear connector. The study included testing of 13 insulated CSP specimens with two types of surface conditions for extruded polystyrene (XPS) insulation and various shapes of shear connectors. All specimens were loaded in direct shear by means of push-out and were consist of three concrete panels, two insulation layer and four rows of GFRP shear connectors. Load-relative slip between concrete panel and insulation response of CSP specimens has been established through push-out shear test. Test results indicate that the surface condition of insulation has a significant effect on the bond strength between concrete panel and insulation. The specimen used XPS foam with 10mm deep slot shows higher bond strength than those used XPS foam with meshed surface. Corrugated GFRP shear connectors show equivalent strength to grid GFRP shear connectors. Cross-sectional area and embedded length of shear connector have a notable effect on overall response and inplane shear strength of the CSP specimens.

• Journal of the Korean Arthroscopy Society
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• v.13 no.2
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• pp.183-187
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• 2009

Purpose: We describe a new and simple technique for arthroscopic fixation of tibial intercondylar eminence avulsion fracture using bioabsorbable pins in skeletally immature patients. Operative Technique: Diagnostic knee arthroscopy is performed using anterolateral and anteromedial portals. Fracture debris and blood clot are debrided to expose the injured site well. The fragment is reduced with the probe and fixed temporarily with a 1.1-mm diameter K-wire that is inserted percutaneously from the anterosuperior aspect of the knee joint. The drill guide is introduced into the joint and the fragment is secured by bioabsorbable, poly-p-dioxanone 1.3-mm pins inserted from different angles. The pins are 40 mm in length. The knee is placed in a long leg cast in extension for 4 weeks to assure that full extension is obtained. Conclusion: Arthroscopic fixation of an tibial intercondylar eminence avulsion fracture using bioabsorbable pins is not a technically demanding, suitable method that ensures fracture healing and restores the stability of the joint.

• Korean Journal of Optics and Photonics
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• v.31 no.1
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• pp.7-12
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• 2020

In this paper, we experimentally investigate the fiber fuse in single-mode 2-kW-class high-power fiber amplifiers, depending on the cooling method at the splicing point. We measured the temperature of the splicing point between the pump-signal combiner and gain fiber as a function of laser output power. The temperature of the splicing point increased from 20 to 32℃ with a slope of 0.01℃/W, up to 1.2 kW of laser output power. At higher powers the temperature of the splicing point increased dramatically, with a slope of 0.08℃/W. After that, the fiber amplifier was destroyed during operation at 1.96 kW of output power by fiber fuse. The bullet shape, a common feature of fiber fuse, was observed in the damaged passive fiber core of the pump-signal combiner. Later, we adopted an improved water-cooled cold plate to increase the cooling efficiency at the splicing point, and investigated the laser output power. The temperature at the splicing point was 35.8℃ with a temperature-rise slope of 0.007℃/W at the maximum output power of 2.05 kW. The beam quality M² was measured to be less than 1.3, and the output beam's profile was a stable Gaussian shape. Finally, neither fiber fuse nor mode instability was observed in the fiber amplifier at the maximum output power of 2.05 kW.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.345-349
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• 2019

In Korea, the mountainous area occupies more than 70% of the whole country, cutting of earth slope that cuts a part of the ground surface is widely used when building infrastructures such as road, railroad, and industrial complex construction. In recent years, regulations on environmental damage have become more strict, and various methods have been developed and applied. Among them, Concrete-Panel Retaining Wall technique is actively applied. Concrete-Panel Retaining Wall is a method to resist horizontal earth pressure by forming a wall by attaching a precast retaining wall to the front of the support material and increasing the shear strength of the disk through reinforcement of the support material. Soil nailing, earth bolt, and ground anchor are used as support material. Among them, ground anchor is a more aggressive reinforcement type that introduces tensile load in advance to the steel wire, and a large concentrated load acts on the front panel. This concentrated load is a factor that creates cracks in the concrete panel and reduces the durability of the retaining wall itself. In this study, steel pipe sleeves and reinforcements were purchased at the anchorage of the panel to prevent cracks, and by applying bumpy shear keys to the end of the panel, the weakness of the individual behavior of the existing grout anchors was improved. The problem of degraded landscape by exposure to front concrete of retaining wall and protrusion of anchorage was solved by the production of natural stone patterns and the construction of sections that do not protrude the anchorage. In order to verify the effectiveness of anti-crack sleeves and reinforcements used in the null, indoor testing and three-dimensional numerical analysis have been performed, and the use of steel pipe sleeves and reinforcements has demonstrated the overall strength increase and crack suppression effect of panels.

• Economic and Environmental Geology
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• v.54 no.1
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• pp.117-126
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• 2021

Satellite magnetic observations reflect the magnetic properties of deep crust about the depth of Curie isotherm that is a boundary where the magnetic nature of the rocks is disappeared, showing long wavelength anomalies that are not easily detected in near-surface data from airborne and shipborne surveys. For this reason, they are important not only in the analyses on such as plate reconstruction of tectonic boundaries and deep crustal structures, but in the studies of geothermal distribution in Antarctic and Greenland crust, related to global warming issue. It is a conventional method to compute the spherical harmonic coefficients from global coverage of satellite magnetic observations but it should be noted that inclusion of erroneous data from the equator and the poles where magnetic observations are highly disturbed might mislead the global model of the coefficients. Otherwise, the reduced anomaly model can be obtained with less corruption by choosing the area of interest with proper data processing to the area. In this study, I produced a satellite crustal magnetic anomaly map over East Asia (20° ~ 55°N, 108° ~ 150°E) centered on Korean Peninsula, from CHAMP satellite magnetic measurements about mean altitude of 280 km during the last year of the mission, and compared with the one from global crustal magnetic model (MF7). Also, a comparison was made with long wavelength anomalies from EMAG2 model compiled from all near-surface data over the globe.

• Journal of the Korean Geotechnical Society
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• v.24 no.7
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• pp.61-73
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• 2008

Piles of a bridge pier are connected with the column through the pile cap (footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. Connection methods between pile heads and the pile cap are divided into two groups : rigid connections and hinge connections. Domestic design code has been specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However, some specifications prescribe that conservative results through investigations of both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which has high-quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) is unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the large diameter drilled shaft and the pile cap for Incheon Bridge which will be the longest bridge of Korea were investigated through the full modeling for rigid connection conditions.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.182-199
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• 2023

Since 2021, government departments have been promoting Automated Driving Technology Development and Innovation Project as national research and development(R&D) project. The automated vehicles and service technologies developed as part of these projects are planned to be subsequently provided to the public at the selected Living Lab City. Therefore, it is important to determine a spatial area and operation section that enables safe and stable automated driving, depending on the purpose and characteristics of the target service. In this study, the static Operational Design Domain(ODD) elements for Level 4 automated driving services were reclassified by reviewing previously published papers and related literature surveys and investigating field data. Spatial analysis techniques were used to consider the reclassified ODD elements for level 4 in the real area of level 3 automated driving services because it is important to reflect the spatial factors affecting safety related to real automated driving technologies and services. Consequently, a total of six driving mode changes(disengagement) were derived through spatial information analysis techniques, and the factors affecting the safety of automated driving were crosswalk, traffic light, intersection, bicycle road, pocket lane, caution sign, and median strip. This spatial factor analysis method is expected to be useful for determining special areas for the automated driving service.

• Korean Journal of Culture and Social Issue
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• v.15 no.1
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• pp.169-186
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• 2009

This study aims to investigate the relationship between personality, especially temperament and subjective well-being. The participants were 681 college students (211 males and 470 females), whose ages ranged from 17 to 37 (M=20.91, SD=2.36). The instruments utilized in the present study were Korean Version of BAS/BIS Scale, The Big Five Locator, Satisfaction with Life Scale, Life Satisfaction Motivation Scale, Life Satisfaction Expectancy Scale, Emotion Frequency Test, and Subjective Happiness Scale. Result indicated that women expected more positive future than men did, while no gender differences were found in any other well-being variables. Correlational analyses revealed that emotional stability and extroversion were closely associated with life satisfaction, happiness, positive and negative emotion, whereas behavioral activation system (BAS) and behavioral inhibition system (BIS) were more closely associated with motivation to live and expectancy of satisfactory life. There was close relationship between conscientiousness and subjective well-being, because they were college students. As a internal factor, personality was better predictor for subjective well-being of female students. For instance, it accounted for around 35% variance of female's subjective happiness. The present findings reiterate the role of personality in quality of life, and it was discussed with characteristics of subjects, situational factors, and previous studies.

• Korean Journal of Environmental Agriculture
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• v.20 no.4
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• pp.289-296
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• 2001

The effects of HRT and effluent time on removals of pollutants in the electrochemical pilot were investigated. COD removal after 8 hour electrochemical reaction time in HRT 30 and 60 minutes were higher than that of 15 minute HRT. Turbidity removal was 90% or greater regardless of conditions during effluent time. Removals of T-N and T-P during effluent time in HRT 30 and 60 minutes were $71{\sim}74%$ and $85{\sim}98%$, respectively. To evaluate the combination of activated sludge process and continuous electrochemical as pretreatment, the removal efficiencies of pollutants was investigated. In two treatment processes of a single activated sludge system and a electrolysis pilot plus activated sludge systems, SVI and MLSS during effluent time were kept with $82{\sim}112$ and $1,230{\sim}1,750$ mg/L, respectively. COD removal was approximately 90% at early effluent time for both treatment systems, but COD removal in a single activated sludge was slightly decreased as effluent time went by, compared with the single activated sludge COD removal was slightly increased in the early stage of the electrolysis plus activated sludge system. Turbidity removal during effluent time was higher than 95% for both treatment systems. T-N removals during effluent time in a single activated sludge system and a electrolysis pilot plus activated sludge systems were $62{\sim}74%$ and $72{\sim}86%$, respectively. T-P removal in a electrolysis pilot plus activated sludge systems was increased by 9% at early effluent time and 15% after 72 hours of effluent time in compared with a single activated sludge system.