• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.332-345
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• 2023

Objectives: We examined the association of hearing with cardio-metabolic diseases, dyslipidemia, hypertension and diabetes mellitus according to the personal and occupational characteristics of workers exposed to noise. Methods: The subjects of the study were 237,028 workers who underwent 2, 3, and 4 kHz airway pure tone audiometry in 2015 and who underwent clinical tests to diagnose cardiovascular-metabolic diseases. Cardiovascular-metabolic diseases were defined using reference values for respective items including blood pressure (systolic/diastolic), fasting blood glucose, cholesterol, and triglycerides. The airway pure tone hearing threshold of 2, 3, and 4 kHz, the average threshold of 2-3-4 kHz, and the hearing loss by the average threshold of the primary examination were distinguished. Results: Workers with cardiovascular-metabolic disease had significantly higher average hearing thresholds and higher rates of hearing loss. Logistic regression analysis, which adjusted for demographic variables of gender and age and occupational variables such as workplace size, industry, and type of work, and cardiovascular-metabolic disease as independent variables, showed that the odds ratio of hypertension to hearing loss in the mid-frequency was 1.239 (95% confidence interval: 1.118-1.374). For hypertension was 1.159 (1.107-1.214) and for diabetes it was 1.166 (1.104-1.230) for hearing loss in the high-frequency. Hearing loss measured by mean hearing was 1.178 (1.105-1.256) for hypertension and 1.181 (1.097-1.271) for diabetes. Conclusions: Cardiovascular-metabolic diseases in noise-exposed workers are associated with an increased risk of hearing loss and should be accompanied by bio-monitoring of cardiovascular-metabolic diseases in addition to auditory surveillance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.5
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• pp.761-773
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• 2023

This paper proposes a method to increase the power-analysis resistance of the neural network model's feedforward process by replacing the exponential-based activation function, used in the deep-learning field, with an approximated function especially at the multi-layer perceptron model. Due to its nature, the feedforward process of neural networks calculates secret weight and bias, which already trained, so it has risk of exposure of internal information by side-channel attacks. However, various functions are used as the activation function in neural network, so it's difficult to apply conventional side-channel countermeasure techniques, such as masking, to activation function(especially, to exponential-based activation functions). Therefore, this paper shows that even if an exponential-based activation function is replaced with approximated function of simple form, there is no fatal performance degradation of the model, and than suggests a power-analysis resistant feedforward neural network with exponential-based activation function, by masking approximated function and whole network.

• Korean Journal of Agricultural and Forest Meteorology
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• v.26 no.2
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• pp.115-125
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• 2024

Wind is a meteorological factor that has a significant impact on agriculture. Gust cause damage such as fruit drop and damage to facilities. In this study, low-altitude wind speed prediction was performed by applying physical models to Local Ensemble Prediction System (LENS). Logarithmic Law (LOG) and Power Law (POW) were used as the physical models, and Korea Ministry of Environment indicators and Moderate Resolution Imaging Spectroradiometer (MODIS) data were applied as indicator variables. We collected and verified wind and gust data at 3m altitude in 2022 operated by the Rural Development Administration, and presented the results in scatter plot, correlation coefficient, Root Mean Square Error (RMSE), Normalized Root Mean Square Error (NRMSE), and Threat Score (TS). The LOG-applied model showed better results in wind speed, and the POW-applied model showed better results in gust.

• Economic and Environmental Geology
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• v.23 no.2
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• pp.245-259
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• 1990

Petrochemical analyses of granitic rocks including trace element, REE and oxygen isotope were carried out to understand petrogenesis of plutonic rocks from the Chungju, Wolaksan and Jecheon granite batholiths, which might be related with tungsten-base metal-fluorite mineralization in the Hwanggangri metallogenic province. Different geochemical characteristics such as major and trace elements were found between Jurassic Daebo granitic rocks (Chungju, Jecheon, Wonju, and Boeun granitic rocks) and Cretaceous Bulgugsa granitic rocks (Wolaksan, Muamsa and Sokrisan granitic rocks). Cretaceous granitoids are characterized by high $SiO_2$and $K_2O$ contents and low $TiO_2$, $Al_2O_3$, MgO and CaO contents. They also have relatively high contents of trace elements(Zn, V, Co, Cr, Sr, and Ba) in comparison with the Jurassic granitoids. (Eu)/($Eu^*$) and $(La/Lu)_{CN}$ ratios of Jurassic plutons vary from 0.78 to 1.13 and from 26.02 to 30.5, respectively, while the ratios of Cretaceous ones range from 0.22 to 0.28 and from 4.42 to 14.2, respectively. The REE patterns of the Cretaceous and Jurassic granitic rocks have quite different Eu anomalies: large negative Eu anomaly in the former, and mild or absent Eu anomaly in the latter. The large Eu negative of Cretaceous granitic rocks are interpreted as a differentiated product of fractional crystallization of granitic magma deduced by Rayleigh fractionation model(Tsusue et al., 1987). Oxygen isotopic compositions of quartz for Daebo and Bulgugsa granitic rocks range from 9.98 to 10.51‰ and from 8.26 to 9.56‰, respectively. The Daebo granitic rocks enriched in $^{18}0$ suggest that the magma be undergone different partial melting processes from the Bulgugsa ones. Of the Bulgugsa granitoids, Wolaksan and Sokrisan mass have different contents of trace elements and ${\delta}\;^{18}0$ values of the silicate minerals, which indicate that they are not from the identical source of magma. Many mineral deposits are distributed in and/or near the Wolaksan and Muamsa granitic rocks, but a few mineral deposits are found in and near the Chungju and Jecheon granite batholiths. It might be depend on geochemisty of the related igneous rocks which have low contents of Ba, Sr, Co, V, Cr, Ni, Zn and high contents of Nb and Y, and on lithology of country rocks such as cabonate and noncarbonate rocks.

• Journal of the Korean Association of Geographic Information Studies
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• v.17 no.1
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• pp.35-49
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• 2014

In order to understand the impacts of surface characteristics and the distance from the urban heat island center to suburban areas on the mean night time air temperature, we analyzed GIS and AWS observational data. Spatial distributions of mean night time air temperature during the summer and winter periods of 2004-2011(six years) were utilized. Results show that the temperature gradients were different by distance and direction. We found high correlation between mean night-time air temperature and artificial land cover area within 1km and 200m radii during both summer(R=0.84) and winter(R=0.78) seasons. Regression models either from 1km and 200m land surface data explained the distribution of night-time temperature equally well if the input data had sufficient resolution with detailed attribute including building area and height.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.1
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• pp.12-25
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• 2011

It is needed to preserve good effects and to prevent bad influences on local climate in urban and environmental planning. This study seeks to develop climate analysis maps to provide realistic information considering local air temperature and wind flows. Quantitative analyses are conducted by CAS for the production, transportation, and stagnation of cold air, wind flow and thermal conditions by incorporating GIS analysis on land cover and elevation and meteorological analysis from MetPhoMod - a mesoscale weather model. The CAS helps The easier analysis and assessment of urban development on local climate. It will contribute to the better life of the people in cities by providing better understanding of the local climate to the urban space planners.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.4
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• pp.124-137
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• 2012

Climate analysis is important in urban planning for human comfort. Synoptic weather conditions can only resolve the 30% of local variance of wind conditions whereas 70% of the variance arise from local terrain, buildings, and other small scale thermal conditions. Climate Analysis Seoul (CAS) was developed to resolve such micro-scale climate. The Local-scale air temperature Deviation (LD) analysis map from CAS showed the co-existence of built-up and suburban areas in the study region (CR, Cold-air analysis Region) despite its small extent. Temperature, humidity, wind speed, and wind direction were monitored in CR. Hourly observed cooling rate agreed well with LD. Cold air production, transportation, and stagnation was visualized by the observed Vertical Temperature Gradient (VTG) along the small stream in CR. VTG observed at the upper-most stream can be divided into two components: radiative cooling and cold air inflow from outside. Radiative cooling exists regardless of the wind speed whereas cold air inflow occurs only with calm wind. From the regression analyses based on the wind speed, the inflow portion was determined as 84% of radiative cooling. Climate analysis in the future will be able to characterize the changes in cold air by urban development plan to support the human comfort.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.1
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• pp.127-133
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• 2020

Most sewage treatment plants located offshore are discharged to the shore either directly or through rivers. Therefore, the water quality of the treated water discharged from the sewage treatment plant affects the water quality of the river water discharged to the river and the ocean. In this study, field surveys and numerical simulations were conducted to investigate the effect of treated water from the sewage treatment plant adjacent to the coastal environment. As a result of analyzing the water quality and sediment quality with the samples collected from the river and the estuary where the treated water was discharged to understand the impact on the coast, the treated water discharged from the sewage treatment plant was discharged to the river without exceeding the design criteria. However, the water quality discharged to the shore through estuaries was more contaminated than treated water. The cause of water quality deterioration of coastal effluent is due to the sedimentation of estuary temporarily by longshore sediment sransport which appeared around the estuary, the occurrence of estuary obstruction, and the increase of stagnant time in the estuary. As it was released and discharged, it was analyzed to affect the water quality, water quality and marine life around the estuary. Therefore, in the case of the east coast where the longshore sediment transport is strong, when planning the sewage treatment facility discharged to the ocean, it is necessary to closely examine the water quality change of the river water in the treated water such as the river mouth occlusion by the longshore sediment transport.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.8
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• pp.695-700
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• 2014

In the present study, the melting temperature depression of Sn nanoparticles manufactured using the modified evaporation method was investigated. For this purpose, a modified evaporation method with mass productivity was developed. Using the manufacturing process, Sn nanoparticles of 10 nm size was manufactured in benzyl alcohol solution to prevent oxidation. To examine the morphology and size distribution of the nanonoparticles, a transmission electron microscope was used. The melting temperature of the Sn nanoparticles was measured using a Differential scanning calorimetry (DSC) which can calculate the endothermic energy during the phase changing process and an X-ray photoelectron spectroscopy (XPS) used for observing the manufactured Sn nanoparticle compound. The melting temperature of the Sn nanoparticles was observed to be $129^{\circ}C$, which is $44^{\circ}C$ lower than that of the bulk material. Finally, the melting temperature was compared with the Gibbs Thomson and Lai's equations, which can predict the melting temperature according to the particle size. Based on the experimental results, the melting temperature of the Sn nanoparticles was found to match well with those recommended by the Lai's equation.

• Journal of Animal Environmental Science
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• v.12 no.2
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• pp.51-60
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• 2006

Studies were carried out using growing to finishing pigs to investigate adequate floor space ($m^2/pig$) in Jeju environment. A randomized block design was used to compare the effect of pig performance on 3 stocking rates (low $0.56 m^2/pig$, medium 0.70 and high 0.90). Liveweight gain and feed intake were measured over a 4 week(Growth stage 1 and Growth stage 2) period or a 3 week(Growth stage 3) period. In growth stage 1 (43 to 65 kg body weight ; BW), daily weight gain was significantly higher in the medium stocking rate than in low or high (P<0.05). However, no significant difference in daily weight gain was found among treatments in growth stage 2(65 to 91 kg) or 3 (91 to 105 kg). Dressing percentage, back fat thickness and carcass grade were also not different (P>0.05). In conclusion, daily weight gain of pigs reared in medium density appeared to be higher than in the other groups during the early growing period which is $0.70m^2/pig$ and similar to that recommended by National Livestock Research Institute, RDA.