• The Bulletin of The Korean Astronomical Society
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• v.44 no.2
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• pp.38.1-38.1
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• 2019

The formation and evolution of galaxies is known to be fundamentally linked to the local environment in which they reside. In the highest-density cluster environments, galaxies tend to be more massive, have lower star formation rates and dust content, and a higher fraction have elliptical morphologies. The stellar populations of these cluster galaxies are older implying that they formed the bulk of their stars much earlier and have since evolved passively. Quantifying the specific environmental factors that contribute to shaping cluster galaxies over the Hubble time and measuring their early evolution can only be accomplished by directly tracing the galaxy growth in young clusters and forming porto-clusters. In this talk, I will present a novel technique designed to map out the total dust obscured star formation relative to where existing stars lie. I will demonstrate that this technique can be used 1) to determine if/where/when the activity is heightened or suppressed in dense cluster environment; 2) to measure the total mass and spatial distribution of stellar populations; and 3) to better inform theoretical models. Our ongoing work to extend this analysis out to protoclusters (z~2-4) will be discussed.

• Journal of the Society of Disaster Information
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• v.18 no.3
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• pp.532-541
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• 2022

Purpose: The purpose of this study is to suggest that the existing power demand prediction method including power demand according to fine dust is included in the existing power consumption by using an air purifier to improve the air quality due to fine dust. Method: The method of the study was compared and analyzed using data on the concentration of fine dust in Seoul for three years, household power consumption, and climate observation, and the effect of fine dust on power consumption in Seoul was identified in April and October. Result: The power consumption of home air purifiers in Seoul due to fine dust differences between April and October was calculated to be 2,141 MWh, accounting for 3.4% of the total difference in the use of home appliances in April and October. Conclusion: The effect of fine dust on household power consumption was verified, and power demand prediction is essential for economic system operation and stable power supply, so power consumption due to fine dust should be considered as well as focusing on power consumption of existing air conditioners and heaters.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.3
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• pp.294-305
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• 2012

The objective of this study is to estimate the chemical compositions and to identify qualitative sources of fall-out particles in study area. Also, this study used a spatial analysis to estimate spatial distributions and average deposition flux. In this study, the chemical compositions of fall-out particle samples collected at Muncheon lake from May 2010 to January 2011 were analyzed by ICP and IC. The monthly trend of deposition fluxes for fall-out particles showed highest in June ($107.61kg/km^2/day$) and lowest in October ($22.22kg/km^2/day$). The average fluxes of Fe, Si, Al, Zn and Ba are 0.44, 0.24, 0.20, 0.17, $0.09kg/km^2/day$, respectively. Also, the average fluxes of $NO_3^-$, $SO_4^{2-}$, $NH_4^+$, $Ca^{2+}$, and $Na^+$ are 6.48, 5.01, 4.96, 1.75, $1.37kg/km^2/day$, respectively. A Factor analysis identified four sources such as 1) nonferrous metal, motor vehicle, and agriculture, 2) soil, 3) field burning, incineration, and 4) road dust and oil burning. The IDW (inverse distance weighting) spatial analysis method was used to estimate spatial distribution and average deposition flux for fall-out particles. A total average deposition fluxes estimated in Muncheon lake were 936.15 kg/month. The spatial distribution trend of deposition flux showed higher at site 1 and 2 than at site 3, 4 because local road is adjacent to the site 1 and 2.

• The Bulletin of The Korean Astronomical Society
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• v.41 no.2
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• pp.29.4-29.4
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• 2016

The relations between star formation and properties of molecular clouds are studied based on a sample of star forming regions in the Galactic Plane. Sources were selected by having radio recombination lines to provide identification of associated molecular clouds and dense clumps. Radio continuum and mid-infrared emission were used to determine star formation rates, while 13CO and submillimeter dust continuum emission were used to obtain masses of molecular and dense gas, respectively. We test whether total molecular gas or dense gas provides the best predictor of star formation rate. We also test two specific theoretical models, one relying on the molecular mass divided by the free-fall time, the other using the free-fall time divided by the crossing time. Neither is supported by the data. The data are also compared to those from nearby star forming regions and extragalactic data. The star formation "efficiency," defined as star formation rate divided by mass, spreads over a large range when the mass refers to molecular gas; the standard deviation of the log of the efficiency decreases by a factor of three when the mass of relatively dense molecular gas is used rather than the mass of all the molecular gas.

• Journal of the Korean Chemical Society
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• v.6 no.2
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• pp.155-157
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• 1962

A tiny dust found at the balcony of the Institute indicated about 8,0000 counts per minute by T.G.C.-2 Geiger-Muller tube (1.8mg/$cm^2$ window-thickness) at the distance of 2cm from the window. The main fission fragments, as identified by the present analysis, are 12.5day Ba-140 and 33.1 day Ce-141. The gamma energies were determined using $2"{\times}2"$ NaI(Tl) scintillation detector connected to RCL-256 channel pulse heigt analyzer. The beta energies were evaluated by Feather plot.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.104-114
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• 1997

This study was carried out to research the influence of climatic conditions including wind direction, wind speed on air pollution in Seoul. The data were obtained from the 4 sites of air pollution monitoring stations in Seoul from '95 to '96, and analyzed statistically by SAS program. The results were as follows 1. The prevailing wind directions by season in each site were as follows Nangajwa-dong were showed SE in spring, fall, winter and WNW in summer. Ssangmun-dong were showed NW in spring, fall, winter and NNE in summer. Kuro-dong were showed SW in spring, summer, ENE in fall and NW in winter. Bangi-dong were showed WNW in four seeasons. 2. The concentrations of 5 kinds(SO$_2$, Dust, NO$_2$, CO, THC) of air pollutants were relatively low in west wind. In case of O$_3$ was opposite. 3. The concentrations of 5 kinds of air pollutants were increase with decreasing wind speeds. 4. The washing effects of air pollution by rain were significant. The concentrations of 5 kinds of air pollutants were high when the humidity were 61-80%, and low as it were 0-20%. In case of O$_3$ was opposite. 5. All of air pollutants concentrations but O$_3$ were high when the UV intensity level and temperature within the range of above zero were low level.

• Explosives and Blasting
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• v.34 no.3
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• pp.10-16
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• 2016

Recently, transition from open pit to underground mining in limestone mines is an increasing trend in Korea due to environmental issues such as noise, dust and vibrations caused by crushers and equipment. The severe damages in the surrounding rock mass of underground opening caused by explosive blasting may lead to rock fall hazards or casualties. It is well known that variables which mainly affect blast-induced rock falls in underground mining are: blast vibration level, joint orientation and distribution and shape of the cross sections of underground structures. In this study, UDEC program, which is a DEM code, is used to simulate blast vibration-induced rock fall in underground openings. Variation of joint space, joint angle and joint normal stiffness was considered to investigate the effect of joint characteristics on the blast vibration-induced rock fall in underground opening. Finally, jointed rock mass models considering blast-induced damage zone were examined to simulate the critical blast vibration value which may cause rock falls in underground opening.

• Korean Journal of Artificial Intelligence
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• v.8 no.2
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• pp.1-5
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• 2020

Children's home accidents are less common than in the past. However, safety accidents continue to occur due to carelessness of the parents. To solve the problem, there are fall prevention screens that can withstand the weight of children, and safety railings that can be adjusted directly to solve the problem. However, these have disadvantages such as stability, convenience, and damage to the landscape. In this paper, we developed an automatic safety accident prevention fence system that can be installed on a window using Arduino, eliminating the disadvantages of previous safety accident prevention products. This system measures the height of a person standing in front of the fence and the distance between the person and the fence with two infrared sensors and moves automatically using a motor. In addition, in accordance with the U-Healthcare society, users can check the temperature, humidity, and fine dust concentration of the external environment through mobile. Each information can be obtained through DHT 11 sensor, fine dust concentration sensor, and Bluetooth connected toArduino. These can help the user's health care.

• Journal of the Ergonomics Society of Korea
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• v.35 no.5
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• pp.343-359
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• 2016

Objective:In this study, we designed working clothes for livestock farmers to wear in spring and autumn to improve their work efficiency, conducted a physiological test on their performance, and evaluated their comfort. Background: In recent years, livestock farming in Korea has expanded, yet farmers' safety and sanitation levels remain low in hazardous environments that include organic dust, toxic gas, and heat stress, as well as the risk of accidents. Furthermore, most livestock farmers wear ordinary or dust-resistant clothes that are unsuitable for rearing livestock and compromise their safety and health. Thus, it is important to design specialized working clothes for livestock farmers that are comfortable and that minimize their health and safety risks. Method: To this end, we examined the literature on livestock (poultry, swine, and cattle) farmers' safety and sanitation issues, designed appropriate working clothes, and tested them in terms of sensory feel, physiological response, and subjective comfort. Results: The respondents expressed satisfaction with the new working clothes. The results of a physiological test showed a decline in temperature and humidity inside the clothes, a lower pulse rate, and a lower oxygen intake compared to the measurements taken when famers wore their previous working clothes. This indicates a fall in heat stress and fatigue, which was mostly consistent with the results of the assessment of subjective comfort. Conclusion: The results of the analysis show an improvement in the comfort of the new working clothes compared to the dust-resistant clothes that are widely worn. Based on this study, the new working clothes need to be further tested and evaluated to improve the design. Application: This study is expected to contribute to designing better working clothes for livestock farmers.

• Journal of Environmental Science International
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• v.29 no.7
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• pp.761-772
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• 2020

This research investigated the meteorologically relevant characteristics of high PM_2.5 episodes in Busan. The number of days when daily mean PM₁₀ concentration exceeded 100 ㎍/㎥ and the PM_2.5 concentration exceeded 50 ㎍/㎥ over the last four years in Busan were 24 and 58, respectively. Haze occurrence frequency was 37.6% in winter, 27.4% in spring, 18.6% in fall, and 16.4% in summer. Asian dust occurrence frequency was 81.8% in spring, 9.1% in fall and winter, and 0% in summer. During summer in Busan, high PM_2.5 episode occurred under the following meteorological conditions. 1) Daytime sea breeze. 2) Mist and haze present throuout the day. 3) Anti-cyclone located around the Korean peninsula. 4) Stable layer formed in the lower atmosphere. 5) Air parcel reached Busan by local transport rather than by long-range transport. These results indicate that understanding the meteorological relevance of high PM_2.5 episodes could provide insight for establishing a strategy to control urban air quality.