• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.37-40
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• 2001

This paper describes a study for the development of light weight transformer with hybrid insulation system consists of A class insulation material and H class insulation material.

• Journal of Advanced Marine Engineering and Technology
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• v.7 no.2
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• pp.15-21
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• 1983

Preparing for treatment and management of the emulsified fuel oil which will be generalized henceforth, this paper is an attempt to examine the viscosity-temperature characteristics of emulsified heavy fuel oil which is mixed with water and emulsifier in various mixture ratio by mechanical mixer. The experimental results are summarized as follows: 1. The viscosity-temperature characteristics of the emulsified C & B grade heavy fuel oil mixed with water of same or less weight, is changed according to log.log(v+0.6)=b-3.8log T. 2. The emulsifier has to be added to the emulsified A grade heavy fuel oil mixed with water of same or less weight, because it is instable. Especially if the emulsifier is sodium stearate, it is added more than 0.3% of the weight of oil and water. 3. In the emulsified A grade heavy fuel oil mixed with water and emulsifier, the higher the ratio of water addition becomes, the higher the viscosity is and the more the viscosity-temperature slope decreases. But the higher the ratio of emulsifier addition is, the more the viscosity-temperature slope increases. In this case, the linearity of viscosity-temperature characteristic curve is poorer than that of B and C grade heavy fuel oil. 4. In the emulsified A grade heavy fuel oil mixed with emulsifier of 0.3% or less, the emulsion type is O/W type when water addition ratio is 40%, but it is W/O type when it is 10%, 20%, 30% and 50%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.269-274
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• 2004

The aims of this study were to Investigate the floor impact noise isolation performance of floating floor with isolation materials and propose the improvement direction of floor impact noise measurement method and evaluation classes using impact ball. Reduction of light-weight impact sound pressure level can be achieved by the finishing materials, such as vinyl finishing material and wooden flooring with isolation materials. Floor impact noise Isolation material which satisfy the properties of the floor impact noise isolation materials cause resonance in the low frequency band and worsen heavy-weight impact sound pressure level. Heavy-weight impact sound level can be reduced by using noise reduction flooring, ceiling and increase of slab thickness. Strong impact force in low frequency bang below 63Hz of bang machine is not similar to human impact source and causes some problem in evaluating heavy-weight impact noise but heavy-weight impact noise measurement and evolution using impact ball which is very similar to human impact is more reliable than bang machine. Correction value on the background noise and sensitivity of residents should be considered on the floor impact noise evaluation classes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.7
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• pp.41-47
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• 2021

In this study, the hinges of heavy weight doors were designed and analyzed in line with the trend that built-in appliances are becoming larger and the weight of doors is also increasing. The main specification of the heavy weight door hinge is to allow the deflection at the end of the door to be less than 2 mm when opening and closing, including the automatic closing, slow closing, and closing force control functions. The structural analysis of the design mechanism, component design, and methods for improving the deflection are as follows: 1) Mechanism of the automatic closing function should sense automatically using the spring compression force at a specific angle by the contact between the cam and the cam module roller. 2) Through structural analysis, the maximum stress of the door was found in the link pin hole connected to the pin at each link. 3) Consequently, the pin holder was designed and applied, with little variance, but up to 93% of the specification limit.

• Korean Journal of Health Education and Promotion
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• v.34 no.1
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• pp.1-12
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• 2017

Objectives: The aim of this study was to verify relationships between light- and heavy alcohol drinking and health-risk behaviors such as smoking, inappropriate weight control, physical inactivity, and sexual activity among adolescents. Methods: The data of 68,043 adolescents in middle- and high school collected from the Korea Youth Risk Behavior Web-based Survey in 2015 were analyzed. For statistical analysis, logistic regression model was used. Results: The rate of heavy alcohol drinking increased with increasing age up to 21.5% among boys and 13.9% among girls. Among boys, heavy alcohol drinkers were at a higher risk of smoking (adjusted odds ratios [OR]=3.3, 95% confidence interval [CI]=2.8-3.8), inappropriate weight control (OR=1.7; 95% CI=1.4-2.1), having sexual intercourse (OR=3.6; 95% CI=3.0-4.2) than light drinkers. Multiple health-risk behaviors of smoking, inappropriate weight control and sexual intercourse also increased in accordance with the severity of drinking alcohol beverage compared to non-drinker. Physical inactivity was decreased among heavy drinkers compared to light drinkers (OR=0.8; 95% CI=0.7-0.9 for inactivity of moderate exercise). Similar results were observed among girls. Conclusions: Alcohol drinking especially heavy alcohol drinking among adolescents is related to other risky behaviors including smoking, inappropriate weight control, and sexual activity. To prevent health problems in adolescents, it is necessary to adopt a combined approach regarding heavy drinking and health-risk behaviors.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.581-586
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• 2008

This study aims to examine the existing single rating index in terms of level reduction limit of heavy-weight floor impact sound. To achieve this goal, sounds which have same loudness according to rating methods were suggested to subjects. And followings are results. 1) The rating method of measurement frequency level average is more suitable than that of other methods which are dependent on specific frequency for rating heavy-weight floor impact sound. 2) Level average for measurement frequency of 31.5Hz - 500Hz is more correspondent to psycho-acoustic response than that of measurement frequency of 63Hz - 500Hz which is for KS F 2863-2, existing rating method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.3
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• pp.282-287
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• 2009

This study aims to examine the existing single rating index in terms of level reduction limit of heavy-weight floor impact sound. To achieve this goal, sounds which have same loudness according to rating methods were suggested to subjects. And followings are results. 1) The rating method of measurement frequency level average is more suitable than that of other methods which are dependent on specific frequency for rating heavy-weight floor impact sound. 2) Level average for measurement frequency of $31.5\;Hz{\sim}500\;Hz$ is more correspondent to psycho-acoustic response than that of measurement frequency of $63\;Hz{\sim}500\;Hz$ which is for KS F 2863-2, existing rating method.

• The Korean Journal of Ecology
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• v.20 no.1
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• pp.51-59
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• 1997

To investigate the distribution of heavy metal concentrations in Onsan bay, concentrations of cadmium, copper, zine and lead in surface sediments and the periwinkles (Littorina brevicula) were determined in Feburary and July, 1996. The ranges of cadmium, copper, zinc and lead concentrations in the surface sediments were 0.08-3.72, 3-307, 49-1273 and 15-399 ${\mu}g/g$ dry weight, respectively, The decrease of concentration in heavy metals with distance from Daejeong stream indicated that this stream is the pollutant source of heavy metals in Onsan Bay. The concentrations of cadmium, copper, zinc and led in L. brevicula were 0.11-11.81, 21-212, 30-96 and 0.26-4.12 ${\mu}g/g$ dry weigth in February and 1.01-24.9, 66-325, 54-225 and 0.68-8.41 ${\mu}g/g$ dry weight in July, respectively. These concentrations in L. brevicula were the significantly different (p<0.001) with the season of sampling. However, overall distribution of concentrations of heavy metals in L. brevicula had very similar tendency that concentrations of heavy metal decreased with the distance from the pollutant source irrespective of the two seasons. Therefore, L. brevicula is considered as a useful indicator for heavy metals pollution, According to analysis of the organs, tissues such as the digestive gland, gill and viceral mussel accumulate high concentrations of heavy metals.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.919-922
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• 2003

The correlation between noise and vibration by a heavy-weight floor impact was studied. The triggering technique was used for increasing the reliability and stability to measure the level of sound pressure, sound intensity and vibration acceleration. The simple finite element and rigid body analysis method were suggested to calculate the natural frequencies of the multi-layer floor system. The result show that the isolation material adapted to reduce the light-weight floor impact noise, causing the natural frequency lower, make resonance with dominant driving frequency, and increase the noise level very sharply. Therefore the noise level Peak in the region of low frequency, below 63Hz, would be related with the natural frequencies of the floor system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.255-260
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• 2003

The regulation for floor impact sound level is expected to be amended to 50㏈(L$\_$i, Fmax, AW/) and below in heavy-weight impact sound and 58㏈(L'$\_$n, AW/) and below in light-weight impact sound in Korea. The purpose of this paper is to analyze the influence factors of floor impact sound levels in apartments. The influence factors were air pressure of bang machine, height of microphones, data acquisition rate, etc. The air pressure range of bang machine were from 2.2 Pa to 2.6 Fa. Five microphones were installed at a height of 0.5m, 0.7m, 0.9m, 1.2m, 1.5m or 1.7m from floor level. The floor impact sound level was varied about 1-3㏈(L$\_$i, Fmax, AW/) in heavy-weight impact sound according to the influence factors.