• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.34-39
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• 2010

The purpose of this study is to suggest objective evaluation model as a plan to utilize as opportunity in establishing judgment standard of mutual inspection criteria and to upgrade inspection ability by reviewing and analyzing level of danger and importance in advance based on inspection results of inspection institutions regarding tower cranes used in construction fields. Tower crane is a mechanical device transporting construction supplies and heavy materials to places over 20~150M high from the ground for the period ranging from a short time of 2~3 months to two years after being installed in construction sites in vicinity of buildings or structures and is an important facility indispensable for construction sites. However, since use period after installation is short and professional technical ability of technicians working on-site about of tower crane is poor, systematic and quantitative safety management is not carried out As a part of researches on procedure of RBI(Risk Based Inspection) possible to apply to Knowledge Based System based on knowledge and experiences of experts as well as to tower cranes for solving these problems, quantitative RPN(Risk Priority Number) was applied to RPN utilizing technique of FMEA(Failure Mode and Effect Analyses). When general RBI 80/20 Rule was applied parts with high level of risks were found out as wire rope, hoist up/down safety device, reduction gear, and etc. However, since there are still many insufficient parts as risk analyses of tower crane were not established, it is necessary for experts with sufficient experiences and knowledge to supplement active RBI techniques and continuous researches on tower cranes by sharing and setting up data base of important information with this study as a starting point.

• Journal of dental hygiene science
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• v.10 no.6
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• pp.445-450
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• 2010

The aim of this study was to evaluate the effect according to the fiber type and combination on the reinforcement of heat-polymerized denture base resin. The heat-polymerized resin(Vertex RS, Dentimax, Netherlands) was used in this study. Glass fiber(GL; ER 270FW, Hankuk Fiber Glass, Korea), polyaromatic polyamide fiber(PA; aramid; Kevlar-49, Dupont, U.S.A.) and ultra high molecular weight polyethylene fiber(PE, polyethylene; P.E, Dong Yang Rope, Korea) were used to reinforce the denture base resin specimens. The final size of test specimen was $64mm{\times}10mm{\times}3.3mm$. The specimens of each group were stored in distilled water at $37^{\circ}C$ for 50 hours before measurement. The flexural strength and flexural modulus were measured by an universal testing machine(Z020, Zwick, Germany) at a crosshead speed of 5 mm/min in a three-point bending mode. In this study, all fibers showed reinforcing effects on denture base resin(p<0.05). In terms of flexural strength and flexural modulus, glass fiber 5.3 vol.% showed most effective reinforcing effect on heat polymerized denture base resin. For flexural modulus, PA/GL was the highest in denture base resin specimen for hybrid FRC using two combination (p<0.05). Glass fiber 5.3 vol.% and PA/GL are considered to be applied effectively in reinforcing the heat polymerized denture base resin.

• Journal of Korean Association for Spatial Structures
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• v.8 no.3
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• pp.45-51
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• 2008

A single layer-latticed dome is advantageous for large span structures because it is very stiff despite the light weight of the structure itself. However, this structure becomes easily unstable during erection due to its large size. The Block method is popular with the large span structures. A partial block of the dome is fabricated on the ground and lifted by crane to a designated location of structures. The lifting point selection is very important to create a stable erection and to avoid buckling of members during the erection. The purpose of this study is to analyze the structural behaviors and buckling characteristics according to the lifting point of single-layer latticed domes with triangle network in order to take materials about the safe and economic erection. The conclusions are obtained as follow. 1) The buckling strength of the block part varies with the location of lifting points when it is erected. In case, the height of the dome is lower, the effort of buckling strength of the structure is higher. 2) In buckling strength, the effect of the lifting rope length is smaller than it of the lifting points change.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.220-226
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• 2005

This study evaluated the composition and distribution of marine litters on the sea-bed of the East China Sea. Surveys have been conducted by a benthic trawlnet of Dong-baek training ship of Yosu national university during the cruise of 2002-2004. Distribution density showed high value in C5 (north-western area of Jeju Island) with $110.3kg/km^2$ and those of annual mean were about $31-43kg/km^2$. Fishing gears such as nets, pots, octopus jars and etc. were about 42-72% of debris collected in the East China Sea. Composition ratio of rubber, vinyl. metal, plastic, glass, wood, cloth and etc. were within 25% except C5. Rope and drum showed strong fluctuations with 0-30% according to the trawling sites. Some vinyls and nets made in Korea, China and Japan were much collected. It is estimated that fishing gears were discarded to the sea by fishing operation, deliberately or not. An comprehensive program including continuous research, monitoring for marine litters in the Korean sea were necessary.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.140-155
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• 2020

The purpose of this study is to examine historical wall repair details through analysis of repair data and administrative documents of the Paradise Conservation of Gangjin Muwisa Temple. In addition, the purpose of the project is to examine the differences and commonalities between the materials and construction technology used in the building's walls. The data for repair work conducted in 1935, 1956, and 1982~3 was analyzed and the results of the research were as follows. First, data for the wall construction conducted in 1935 during the dismantling repair showed that the interior structure of the wall was found to follow that of the original, but the first, second, and final layers used different materials. The composition material of the wall consisted of clay, lime and sand, the second layer used sand and plaster, and the last layer used plaster and seaweed paste. Second, the structure of the wall interior, which was found during the 1956 repairs, consisted of wood woven horizontally and vertically. It was confirmed that this had been installed diagonally using a rope. Third, the 1982~3 repair work confirmed that the wall's interior construction conformed to the original method. The lime-sand wall was formed by mixing slacked lime, sand, soil, fodder, and seaweed grass. Fourth, when the various repairs are considered as a whole, it is clear that the interior structure of the wall was made more than 1900 years ago, and the material used in the wall changed in 1935. Fifth, the materials used for each repair differed, but each project had a common view of cultural heritage repair principles in sections that stated the significance of each project.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.2
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• pp.110-115
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• 2011

Objectives: The aim of this study is to survey for finding asbestos containing equipment at the laboratories using picture based questionnaire and polarized light microscopic analysis. Methods: This study was conducted from 2009 to 2010 at a university in Seoul. In 2009, picture based questionnaire was distributed to 100 laboratories during the regular laboratory air quality monitoring. In 2010, we emailed all professors of the same university who have laboratories to participate voluntarily this survey. For the laboratories consented to participate survey, picture based questionnaire was distributed and collected. Suspected asbestos containing material and apparatus were collected at the laboratories which replied they have suspected material and equipment. Collected samples were analyzed with polarized light microscope at the laboratory accredited by ministry of employment and labor in Korea. Results: Total of 18 out of 100 laboratories reported that they had suspected asbestos containing equipment in 2009. Twenty-three samples were collected and three samples (13%), one heating mantle and two pairs of insulation gloves, contained asbestos. Thirty four laboratories reported they had suspected asbestos containing material or equipment in 2010. Sixty samples were collected and four of them (6%), two pairs of insulation gloves, one packing rope in dry oven and, one pair of tongs, contained asbestos. All founded asbestos was chrysotile and the content of chrysotile was more than 90% for all equipment except heating mantle which has less than 1%. Conclusions: We confirmed that asbestos was still used at the laboratories though strict regulations on asbestos use in Korea. The method of picture based questionnaire invented in this study could be applied for asbestos survey to other research institute or university where there are many laboratories because of its simplicity and accessibility without huge man power, cost and time.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.678-684
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• 2016

The detection of an underwater work space boundary is very important when an underwater construction is carried out using seabed type underwater equipment, such as underwater machines for rubble mound leveling, because it can induce industrial disasters. Therefore, divers are needed to mark the underwater work space boundary. A nylon rope is used to improve the convenience during an underwater diver's work. The results showed that the work space boundary can be detected using a sonar system. Using these results, an efficient method to detect the underwater work space boundary can be obtained when an underwater construction is carried out using seabed type underwater equipment.

• Journal of the Korean Applied Science and Technology
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• v.34 no.4
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• pp.737-745
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• 2017

The aim of this study was to develop a community based participatory obesity control program and measure the effects of the program on obesity, exercise habit, eating habit and life habits among obese elementary school children. The community based participatory obesity control program was provided for the experimental group of $4^{th}$ grade elementary school students for 10 weeks. The program included obesity related health educations and counseling once a week, jump rope classes twice a week and folk game classes held once a week. Method: There were 24 students with obesity in the experimental and 27 in the control groups. The collected data were analyzed by the Kolmogorov-Smirnov test, ${\chi}^2$-test, independent t-test and repeated measure ANOVA. Results: After 10weeks of participation in the program, the experimental group showed significantly lower Body Mass Index (p<.001) and waist hip ratio (p=.036), significantly higher exercise habit (p=.004), eating habit (p=.003) and life habit (p=.001) than those in the control group. Conclusion: This study provides evidence that community based participatory obesity management program is effective nursing intervention for managing child obesity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.5
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• pp.906-912
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• 2001

The effects of aerobic exercises and/or supplementation of kimchi on changes of the body composition and plasma lipids of obese middle school girls were studied. Thirty eight girls, 28 obese girls and 10 normal weighed girls, were paricipated. Among obese girls, 8 were assigned to exercise group (FG) 12 were grouped as kimchi group (KG) , and 8 were asked to practice excercise and to take kimchi simultaneously(excercise kimchi group, EKG). Ten girls whose weight is normal asked to remain o their own diet during 6 weeks of experiment (control group, CG)/ EG practiced jogging and rope-jumping for 60 minutes four times a week and KG took 3 g of freeze-dried kimchi packed in a 500 mg capsule daily which is equivalent to 30 g of fresh kimchi, EKC, EG and KG showed beneficial effects on changes of the body composition and plasma lipids compared to those of CG, EG showed greater effect than KG in reducing body fat resulted decrease in BMI, fat mas,. abdominal fat, and triglyceride concentration and increase in HDL-cholesterol. KG seemed to have greater effect on lowering plasma cholesterol and LDL-cholesterol than EG/ But the greatest effects in terms of reduction in weight, BMI fat mass, abdominal fat, total cholesterol, LDL-cholesterol, triglyceride, and increase in HDL-cholesterol were observed from EKG. These results indicate that kimchi supplemenation while practicing excercise might improve the obese state by reducing body fat content as well as reducing plasma lipids.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.6
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• pp.472-482
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• 2019

This paper describes the stabilization of underwater TAS winch system Deploy/Recover operation performance. TAS winch installed on the stern of submarine performs to deploy/recover sensor, towing cable and rope tail which is deployed from the stern and separated from submarine itself. Also TAS winch provides transmission path of power to the sensor and data transmitting/receiving path which data are acquired from underwater environment like sound, depth and temperature. At the step of TAS winch evaluation test, sporadic standstill and rotating speed oscillation phenomenon were occurred. Winch motor provides the available torque to deploy/recover TAS and root cause analysis to the winch motor was done to find exact reason to sporadic malfunction. When winch motor was disassembled, eccentricity of rotor, slip-ring and the other composition part for winch motor were found. These might cause magnetic field distortion. To make TAS winch system more stable and block magnetic field distortion, this paper suggests methods to enhance fixing status installed in winch motor. For reliable data acquisition for TAS winch operation, the deploy/recover function of the improved type of TAS winch was verified in LBTS making similar condition with sea status. At the end of stage, improved type of TAS winch was tested on some functions not only deploy/recover function, but sustainability of TAS operation on specific velocity, steering angle of submarine in the sea trial. Improved type of TAS winch was verified in accordance with design requirement. Also, validity of suggested methods were verified by the sea trial.