• Journal of Environmental Health Sciences
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• v.10 no.2
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• pp.69-77
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• 1984

Air pollution has been one of the severe problems in city area. Sulfur dioxide is the major pollutant among the air pollutants. And the lichen as a botanical indicator have been used to predict the air pollution level. This study was carried out to evaluate the air pollution level in Taejon area through the field survey which were checked lichen status and sulfur dioxide content in the atmosphere. The results were as follows 1. The average sulfur dioxide content in Taejon area was 0.031ppm. The comparison of measurement methods were regression equation, Y= 0.357$\times$+0.014 and correlation factor, r = 0.771. 2. The maximum point of the SO$_2$ level was site No. 2(Daehwa-Dong), 0.087 ppm and the minimum, site No. 8 (Doma 2-Dong), 0.009ppm. 3. Total amounts of sulfur dioxide yearly emitted from Taejon area by fuel consumption estimated 29829.6 tons. 4. The relationship between degree of lichen and sulfur dioxide contents were 0.000~0.020ppm : Zone No. 2 0.020~0.060ppm : Zone No. 1 over 0.060ppm : Zone No. 0

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.6
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• pp.795-810
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• 2019

In this paper, The study was conducted on the method to roughly determine the area and length of the multi-utility tunnel before the planning and design phase of the multi-utility tunnel construction. For this purpose, four feasibility indexes were used: traffic density, population density, disaster prevention index (number of workers), and urbanization rate, which reflect the regional characteristics. The installation criteria were set in consideration of the average value and minimum value of the feasibility indexes for the tunnel type among areas that can be installed in the multi-utility tunnel of Seoul. The analysis area included 200 areas based on 14 zones. The results of the analysis based on the minimum value of feasibility indexes indicated that the tunnel type of multi-utility tunnel is suitable for 39 areas with high traffic volume and population. On the other hand, the 'gun' area, etc., has a wider population than the 'si' and 'gu', suggesting that it is not suitable to install multi-utility tunnel. In addition, it can be seen that the larger the index value centered on the minimum value of each index, the smaller the tunnel type of multi-utility tunnel installation area.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.413-420
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• 2018

Purpose : We present a novel method for the analysis of blue light applied by the analysis method of David L. with optical experiment and blue light by measuring the transmittance by dividing it by the refractive power in the spectacle lens made by MR8. Methods : The lenses of -8.00D, -7.00D, -6.00D, -5.00D, -4.00D, -3.00D, and 0.00D manufactured by MR8 being sold in the market, were selected. The transmittance was measured at the intervals of 5 nm from 200 to 1000 nm with UV-VIS Spectrophotometers (SolidSpec 3700), and they were in range of the blue light (380 to 500 nm) analyzed by a David L.'s analysis method. Results : All of the MR8 lenses selected for this study almost completely blocked at the UV range. A lens of -8.00D was measured as the lowest transmittance of 59.56% in the blue light area and low values were measured at the blue areas 1 and 2 according to the analysis of David L.In the infrared ray area, the transmittance of all lenses gradually decreased. The average value of the luminous transmittance was 23.67% ~ 26.33% and then gradually decreased from -4.00D. Conclusion : Applying the analysis of David L., a minimum of 41.28% and a maximum of 46.60% were measured at the blue light 1 area and a minimum of 87.30% and a maximum of 97.55% were measured at the blue light 2 area. A minimum of 86.83% and a maximum of 96.55% were measured at the blue light 3 area, and the average was 94%. The luminous transmittance of the -3.00D lens was 26.33%, which was the highest, and that -8.00D was 23.67%, which was the lowest.

• Korean Journal of Environment and Ecology
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• v.32 no.5
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• pp.497-506
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• 2018

The purpose of this study was to investigate the proper minimum viable population of a seed bank for the ecological restoration of pine forest using a seed bank. It examined the germinated soil seed bank from August 2010 to November 2011. The results of the correlation analysis showed that the area and the number of herbaceous species were the highest at 0.686. The results of the regression analysis of four variables including the number of woody species, the number of woody individuals, the number of herbaceous species, and the number of herbaceous individuals using the theory of island biogeography to the minimum viable population in studied plots showed that all four variables were significant with area at the level of 0.05, and R square was 0.583. One function was selected between the number of species and the number of individuals from the canonical correlation analysis, and the function square was 0.824. Both canonical function and squared canonical correlation showed significant at the level of 0.01. The result of study recommended the area size of the minimum viable population in pine forest applied by seed bank to be larger than $64m^2$, the number of species to be over 21, and the number of population to be over 120. It also found that the number of herbaceous species determined the cluster size of the seed bank. Therefore, it is necessary to consider herbaceous species that appear in the seed bank.

• Journal of Internet Computing and Services
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• v.13 no.3
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• pp.49-59
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• 2012

Throughout developing digital technology, reproduction of image is growing better day by day. And at the same time, diverse image editing softwares are developed to manage images easily. In the process of editing images, those programs could delete or modify EXIF files which have the original image information; therefore images without the origin source are widely spread on the web site after editing. This matter could affect analysis of images due to the distortion of originality. Especially in the court of law, the source of evidence should be expressed clearly; therefore digital image EXIF file without deletion or distortion could not be the objective evidence. In this research, we try to trace the identification of a digital camera in order to solve digital images originality, and also we focus on lens distortion correction algorism which is used in digital image processing. Lens distortion correction uses mapping algorism, and at this moment it also uses interpolation algorism to prevent aliasing artifact and reconstruction artifact. At this point interpolation shows the similar mapping pattern; therefore we want to find out the interpolation evidence. We propose a minimum filter algorism in order to detect interpolation pattern and adjust the same minimum filter coefficient in two areas; one has interpolation and the second has no interpolation. Throughout DFT, we confirm frequency character between each area. Based on this result, we make the final detection map by using differences between two areas. In other words, thereby the area which has the interpolation caused by mapping is adjusted using minimum filter for detection algorism; the second area which has no interpolation tends to different frequency character.

• Journal of Oral Medicine and Pain
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• v.35 no.3
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• pp.193-202
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• 2010

The purpose of this study was to determine the sites of narrowing/obstruction and to measure the regional severity of narrowing through the evaluation of dynamic changes in upper-airway of healthy subjects. The selected 9 subjects were proved not to have any sleep-related disorder such as snoring or obstructive sleep apnea through clinical examination, radiological examination, sleep study with a portable recording system. Afterward, the Electron Beam Tomography was performed during the waking and sleeping state of subjects, with their mandible in resting and protruded position. Intravenous injection of Dormicum$^{(R)}$ was used for the induction of sleep. The maximum and minimum cross-sectional areas at each airway level during tidal ventilation were measured and the Collapsibility Index for each level of cross-section was also computed. In a comparison with results under variable conditions, the result was showed that the significant difference between each airway level divided with upper, middle, lower region of upper airway is not observed in the average minimum cross-sectional areas and Collapsibility Index. The significant difference only between in wake and sleep state was observed in the average minimum cross-sectional area at the lower region. Also, in wake state, the significant difference between resting and protrusive position of mandible for the average minimum was also observed in cross-sectional area at middle region. In sleep state, no significant difference between resting and protrusive position of mandible was observed in cross-sectional area and the Collapsibility Index.

• Journal of Soil and Groundwater Environment
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• v.11 no.3
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• pp.52-58
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• 2006

Kim and Lee (2005) suggested Minimum Entropy Deconvolution (MED) to estimate the temporal sequence of the relative recharge. However this study by Kim and Lee (2005) was just related to the verification of the conceptual approach with MED. In this study, we try to characterize the applicability of MED in the case of spatially heterogeneous recharge (distance from recharge area). Simulated results were recorded with some specific sampling points. Estimated results from this study show higher than 0.8 in cross-correlation with the original recharge sequence. In addition, the physical and mathematical meanings of the applied filter length was also investigated. It was revealed that the length of filter is highly related to the spatial distance between recharge area and the monitoring site, and the apparent shape of hydraulic head change.

• Journal of Environmental Science International
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• v.4 no.1
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• pp.63-70
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• 1995

Continuous measurements of ground-level ozone (O3) were made in five minutes intervals in the rural area of Korea from July 1993 to June 1994. This site is located in Chongwon, near latitude 36.4$^{\circ}$N, longitude 127.6$^{\circ}$E. The results show that the one-year mean value was 17 ppb, and monthly mean ranged from 6 to 47 ppb. A pronounced maximum in summer and a minimum in winter were found, and these were related to anthropogenic emission and photochemical reaction. Diurnal variations of ozone minimum at 07:00 - 08:00. During the period when ozone concentration was very high (> 80 ppb), the stable winds were from N and UW; on the other hand, when ozone concentration was very low, air movement in the large scale was from the North Pacific Ocean. This suggests that in the rural area the long range transport of anthropogenic pollutants from distant sources can contribute to the larger contribution than the generation of ozone from local sources in the rural area.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.164-169
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• 2020

Use of SiPM has been considered as an alternative to PMT, because of its compact size, low-operating voltage, non-sensitive to electromagnetic, low costs and so on. The main limitation for the use of SiPM is due to its small sensitive area compared to PMT that limits the light collection, and therefore the sensor energy resolution. In this article we studied the effect of increasing the number of SiPM by connecting them in parallel to increase the active detection area. This allowed us to compare the different energy resolution measurements. ¹³⁷Cs has been selected as reference to study the energy resolution for 662 keV gamma-rays. Another investigation was to compare the minimum detectable gamma energy under various SiPM configurations. It has been found that the use of 4 SiPM arrays can greatly improve the energy resolution up to 4% than only one SiPM array, meanwhile use of more than 2 SiPM arrays does not increase the energy resolution significantly. Thus we can conclude that for a large area of cylindrical scintillator (3 × 3 inches), the use of SiPMs are limited to a certain number or certai active area depending on the commercial SiPMs, and its cost should be less than traditional PMT for the cost-effective and compact size considerations. It is well known that the gain of SiPM varies with temperature. In this article, we also calibrated gain to guarantee the same position of photoelectric peak in response of different temperatures.

• Journal of Korean Society of Forest Science
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• v.107 no.4
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• pp.436-445
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• 2018

This study aims to find out factors to affect forest area of public sector such as state forest and estimate optimum area of state forest in Korea. This study was carried out with the rate of public forest and public forest per capita as dependent variables and 15 independent variables to the 35 countries in OECD countries using analysis of linear regression. From research, optimum area of the public forests of Korea was estimated from to minimum 2,136,000 hectares to maximum 2,667,000 hectares, based on OECD countries. The public forest areas of Korea were 1,984,000 hectares in 2010. To reach the average level of OECD countries, it is required that public forest areas of Korea are expended from minimum 152,000 hectares to maximum 683,000 hectares. It is hard to expect that enhancing the areas of public forest in Korea through expanding local government owned forest areas. Therefore, it required that state forest areas are expanded by Korea government.