• Journal of Environmental Health Sciences
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• v.33 no.4
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• pp.283-292
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• 2007

Atmospheric concentrations of radon had been continuously observed in Seoul, Korea since December 1999, as a tracer for long-range transport of air pollutants from China continent to Korea. In order to study radon as a tracer of long-range transport, it is important to know information about the atmospheric distribution and variation of radon concentration and its time variation. Atmospheric radon concentration are measured with electrostatic radon monitor(ERM) at Hanyang University located in Eastern area of Seoul. Air sample is taken into a vessel of ERM, and alpha particles emitted by radon daughters $Po^{218}$ are detected with ZnS(Ag) scintillation counter. Hourly mean concentrations and hourly alpha counts are recorded automatically. The major results obtained from time series observation of atmospheric radon were as follows : (1) The mean of airborne radon concentration in Seoul was found to be $7.62{\pm}4.11\;Bq/m^3$ during December $1999{\sim}January$ 2002. (2) The hourly variation of radon concentrations showed the highest in 8:00AM ($8.66{\pm}4.22\;Bq/m^3$) and the lowest in 3:00AM ($6.62{\pm}3.70\;Bq/m^3$) and 5:00AM ($6.62{\pm}3.39\;Bq/m^3$). (3) the seasonal variation of radon concentrations showed higher during winter-to-fall and lower during summer-to-spring. (4) Correlation between airborne radon concentration and the meteorological factors were -0.21 for temperature, 0.09 for humidity, -0.20 for wind speed, and 0.04 for pressure. (5) The mean difference of airborne radon concentration between Asian dust ($5.36{\pm}1.28\;Bq/m^3$) and non-Asian dust ($4.95{\pm}1.49\;Bq/m^3$) phenomenon was significant (p=0.08). We could identify time series distribution of radon concentration related meteorological factors. In addition, radon can be considered a good natural tracer of vertical dispersion and long-range transport.

• Journal of the Korea Society for Simulation
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• v.29 no.3
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• pp.57-72
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• 2020

To respond to the threat of Long range artillery of North Korea, it is necessary to establish the Korean counter long range artillery intercept system(CLRAIS). The purpose of this study is to study the operational concept of the CLRAIS against the threat of long range artillery of North Korea, and to develop the operational effectiveness process of the CLRAIS. First, we set up the operating concept of the CLRAIS and established the concept of an effectiveness in a many-to-many engagement situation and a process to derive it. Based on this, a tool was developed to analyze the actual effectiveness. In order to find out the factors influencing the effectiveness in many-to-many engagement situations, simulation experiments were performed by combining various variables such as detection assets, engagement control, and launchpad performance. As a result, it was found that in addition to the missile performance, the performance of the detection assets and the engagement control center had a significant impact on the intercept rate and the defense success rate. These findings can be used to understand important indicators in terms of effectiveness in many-to-many engagement situations in the future development of weapon system, and to determine the development direction and target value of each element necessary for the level of defense success rate to be achieved.

• Journal of the Korean Mathematical Society
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• v.35 no.3
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• pp.741-753
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• 1998

Let G(*) be a Borel function applied to a stationary long memory sequence {X$_{i}$} of standard Gaussian random variables. Focusing on the process {G(X$_{i}$)}, the present paper establishes the almost sure representation for the empirical quantile process, that is, Bahadur's representation, and for the empirical process with respect to sample mean. Statistical applications of the representations are also addressed.sed.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.04a
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• pp.133-138
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• 2000

In this paper some shapes of the FBW cross sections were examined to improve the performance of FBW for the long wave. Trapezoidal section and prominence section were examined. Linear potential theory is used and the boundary element method is use for numerical computation. Proper choice of the pontoon geometry may improve the transmission coefficient in the long wave range for a given wave period.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.683-684
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• 2008

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.285-293
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• 2009

Thermal infrared cameras have been conducted actively in various application areas, such as military, medical service, industries and cars. Because of their characteristic of sensing the radiant heat emitted from subjects in the range of long-wavelength($3{\sim}5{\mu}m$ or $8{\sim}12{\mu}m$), and of materializing a vision system, when general optics materials are used, they don't react to the light in the range of long-wavelength, and can't display their optic functions. Therefore, the materials with the feature of higher refractive index, reacting to the range of long-wavelength, are to be used. The kinds of materials with the characteristic of higher refractive index are limited, and their features are close to those of metals. Because of these metallic features, the existing producing method of optical systems were direct manufacturing method using grinding method or CAD/CAM, which put limit on productivity and made it difficult to properly cope with the increasing demand of markets. GASIR, a material, which can be molded easily, was selected among infrared ray optics materials in this study, and the optical system was designed with two Aspheric lenses. Because the lenses are molded in the environment of high temperature and high pressure, they require a special metallic pattern. The metallic pattern was produced with materials with ultra hardness that can stand high temperature and high pressure. As for the lens mold, GMP(Glass Molding Press) of the linear transfer method was used in order to improve the productivity of optical systems for thermal infrared cameras, which was the goal of this paper.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.15-23
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• 2020

As the IoT industry expands, various application services based on location information of devices are released. In order to transmit the location information, various wireless communication technologies such as Bluetooth and Wi-Fi are used. However, these technologies have limited coverage, and cellular networks with relatively wide coverage have the disadvantage of paying for use. In this paper, we implemented our own location information system using LoRa, a low power long distance wireless communication technology. As a result, no cost is incurred and it has relatively wider coverage than other wireless communication technologies using LoRa technology. The implementation system enables LoRa communication based on IPv6 using CoAP and 6LoWPAN, and enables multiple devices to interwork with the existing Internet environment.

• Journal of Korean Medicine for Obesity Research
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• v.22 no.1
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• pp.77-85
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• 2022

While the Coronavirus disease 2019 (COVID-19) pandemic is gradually turning into an endemic disease, concerns about post COVID-19 conditions (Long COVID) are emerging. Obesity is a major risk factor for severe complications of COVID-19, and COVID-19 has a wide range of effects on obesity and metabolic function. This paper aims to examine the interaction between COVID-19 and obesity, the effects and mechanisms of long COVID on obesity, and the role of Korean medicine on long COVID-related obesity. Obesity may worsen with cardiometabolic damage and psychosocial insecurity during COVID-19 and long COVID-induced neuroinflammation, systemic inflammation, mitochondrial dysfunction, and hypoxia also may aggravate obesity. Korean Medicine treatments, which have been widely used to treat obesity, have the potential to improve obesity in the era of long COVID by intervening in these mechanisms.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.04a
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• pp.125-127
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• 1999

• Proceedings of the Optical Society of Korea Conference
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• 2008.07a
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• pp.419-420
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• 2008