• Journal of the Korean Regional Science Association
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• v.35 no.4
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• pp.61-73
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• 2019

Urban development and densification have led to the Urban Heat Island Effect, in which the temperature of urban space is higher than the surrounding areas, and the intensity is increasing with climate change. In addition, when the city's air temperature rises in summer, low-income, elderly population, and socially vulnerable people who have health problems lack the ability to cope with the elevated heat environment. Therefore, this study aimed to identify the urban heat island area of Seoul through Hotspot analysis, which is a spatial statistics technique, and explored physical environments, demographic and socioeconomic characteristics of urban heat island effect areas using logistic regression models. This study performed urban heat island hotspot analysis using the average air temperatures of the 423 administrative dongs in Seoul. Analysis results identified that the urban heat islands were concentrated in Jung-gu, Jongno-gu, Yongsan-gu, and Yeongdeungpo-gu. Logistic regression analysis results indicated that urban heat island areas of Seoul were affected by residential floor area ratio, commercial facility floor area ratio, overall floor area ratio, impervious surface ratio, and normalized difference vegetation index(NDVI). In addition, as a result of analyzing the vulnerable area of thermal environment considering the demographic and socioeconomic characteristics of the heat island area, urban heat island areas of Seoul were significantly associated with the proportion of low-income elderly living alone. The result of this study provided useful insights for urban thermal environmental design and policy development that could improve the thermal environment for the socially disadvantaged urban population.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.5
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• pp.682-689
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• 2014

This study was carried out to discriminate the effects of the ramie leaf according to the drying methods (hot air drying and freeze drying) on antioxidative activity in vitro and antiproliferation in human cancer cells. There were no significant differences in total polyphenol content of ramie leaf ethanol extracts depending on the drying methods, but total flavonoid content was significantly higher in hot air dried ramie leaf (HR) than in freeze dried ramie leaf (FR). The DPPH radical scavenging activity of HR and FR ethanol extracts were found to be 77.74%, and 77.29% in 1000 ppm, respectively. Antioxidative index of HR and FR ethanol extracts measured by Rancimat were lower than those in BHT, BHA, and ascorbic acid, but were higher than that in control. The antiproliferation effect of 80% ethanol extracts of HR and FR on liver cancer cell line (H460), stomach cancer cell line (AGS), and lung cancer cell line (A549) were increased with a dose-dependent manner. The cancer cell growth inhibition activities of HR and FR ethanol extracts at the concentration of $800{\mu}g/mL$ showed greater than 80% on Hep G2 and A549 cell line, and greater than 75% on AGS cell line. These results suggest that HR and FR ethanol extracts possess potential antioxidative effect and antiproliferation in human cancer cells, and those activities of ramie leaf ethanol extracts depending on the drying methods were similar.

• Tunnel and Underground Space
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• v.24 no.1
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• pp.67-80
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• 2014

Long-term stability and delayed failure of granite were evaluated through the laboratory test based on Wilkins method and Brazilian disc test (BDT) which yields tensile strength, mode I fracture toughness and subcritical crack growth parameters. Then, the long-term strength of granite was estimated by using analytical models and long-term stability of compressed air-energy storage (CAES) pilot cavern pressurized up to 5 ~ 6 MPa was evaluated using numerical code, FRACOD with the determined subcritical crack growth parameters. The results of test and analyses showed that the subcritical crack growth index, n was determined as 29.39 and the inner pressure of 5 ~ 6 MPa had an insignificant effect on the long-term stability of pilot cavern. It was also found that the measurement and analysis of acoustic emission events can describe the accumulation of damage due to subcritical crack growth quantitatively. That is, AE monitoring can provide the current status of rock under loading if we make an identical installation condition in the field with that of the laboratory test.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.9 no.1
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• pp.87-98
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• 1999

The objectives of this study were to evaluate exposures to airborne methylene chloride and postshift carboxyhemoglobin (COHb) in blood of workers engaged in processes using blowing or cleaning agents, and to investigate correlation between methylene chloride concentrations and the blood COHb levels of workers. The geometric mean (GM) of workers' exposures (8 hour-time weighted averages, TWA) to airborne methylene chloride during cleaning molds using rags wetted with the solvent in the manufacture of flexible polyurethane foam (GM = 61.4 ppm), during operating the dip tank for cleaning molds in the manufacture of lens (GM = 61.0 ppm), and during cleaning the blowing nozzles by spraying the solvent in the manufacture of shoes (GM = 117.2 ppm) were exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value ($TLV^{(R)}$)-Time Weighted Average (TWA) (50 ppm). The COHb levels were significantly different among groups (p<0.05). The average COHh levels in blood of non-smoking workers were 2.0% in. low-level (<50 ppm) exposure group, and 3.9 % in high-level (>50ppm) exposure group. The average COHb levels in smoking workers were 3.1% in low-level exposure group, and 4.8% in high-level exposure group. The blood COHb levels of no-exposed workers to methylene chloride were 1.8% in non-smoking group, and 2.8% in smoking group. It was found that the COHb level dependeds on the methylene chloride concentration and smoking habit, and was highly correlated with methylene chloride concentration in air. The correlation coefficient was 0.81 among non-smoking workers. The estimated COHb level (3.6%) and 95% upper confidence limit (4.0%) corresponding to TLV-TWA of methylene chloride exceeded the current ACGIH Biological Exposure Index (COHb 3.5%) for carbon monoxide. The estimated COHb level (5.4%) at 100 ppm exceeded the standard (5%) recommended by National Institute for Occupational Safety and Health (NIOSH) for preventing adverse cardiovascular effect. The estimated COHb value and 95% upper confidence limit at 25 ppm of the Occupational Safety and Health. Adminstration (OSHA) Permissible Exposure Limit-TWA (PEL-TWA) were 2.6% and 3.0%, respectively. It is suggested that COHb in blood be kept below 3.0% to comply with OSHA PEL-TWA.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.26 no.1
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• pp.25-33
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• 2015

Background and Objectives:The objective of this study was to investigate the features of post-thyroidectomy subjective voice disorder by Voice Handicap Index (VHI) and Voice Symptom Scale (VOISS) through aerodynamic analysis and to investigate the appropriate voice therapy intervention. Materials and Methods:Twenty post-thyroidectomy patients who had no recurrent laryngeal nerve paralysis through laryngeal stroboscopy were enrolled for this study. Acoustic and aerodynamic evaluations were performed before operation, 2 weeks and 3 months after operation. Subjective voice evaluation was performed by VHI and VOISS. Aerodynamic evaluation was compared and analysed by maximum phonation time(MPT), phonation threshold pressure(PTP), mean air flow rate(MFR), etc. Subjective voice evaluation was surveyed through VHI and VOISS. To evaluate patients' symptoms related to functional voice disorder, scores on physical domain in VHI and VOISS were selected to be compared for each session. Results: The 10 out of 20 participants who complained of voice symptoms had no significant difference with pre-operation in acoustic evaluation, but all showed higher scores on 2 weeks and 3 months after operation compared to pre-operation, in VHI-physical domain and selected questionnaires in VOISS. They reduced MPT and increased PTP value simultaneously. Laryngeal massage and breathing training were simultaneously treated to them, 5 participants resulting in improvement in MPT and PTP compared to pre-treatment. Conclusion:Patients who complained voice change with no organic damage after thyroidectomy were all shown to have reduced MPT and increased PTP in some by aerodynamic evaluations. Reduced MPT may imply some problem in air flow beneath glottis. Increased PTP suggests much more effort in vocalization mechanism than pre-operation. Comparing aerodynamic evaluations in post-thyroidectomy may provide information on behavioral interventions. Additionally, study on laryngeal massage and breathing training simultaneously treated to patients with such voice disorder is needed to be conducted with larger number of participants.

• Journal of Environmental Impact Assessment
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• v.20 no.4
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• pp.497-507
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• 2011

This research studied human health risk assessment of benzene from industrial complexes of Chungcheong Province (Seosan industrial complex) and Jeonla Province (Iksan industrial complex and Yeosoo industrial complex). The residents near the industrial complexes areas can be often exposed to volatile organic compounds (e.g., benzene, toluene, xylenes) through a number of exposure pathways, including inhalation of the organic pollutant via various environmental matrices (air, water and soil), contaminated water, and soil intake. Benzene is well known to be a common carcinogenic and toxic compound that is produced from industrial and oil refinery complexes. In this study, a number of samples from water, air, and soil were taken from the residential settings and public school zones located near the industrial complex sites. Based on the carcinogenic risk assessment, the risk estimates were slightly above $10{\times}10^{-6}$ at all three industrial sites. According to deterministic risk assessment, inhalation was the most important route. The distribution of benzene in the environment would be dependent on vapor pressure, and the physical property influencing the extent of the potential risks. Non-carcinogenic risk assessment of benzene shows that the values of Hazard Index(HI) were much lower than 1.0 at all industrial complexes. Therefore, benzene was not a cause of concern in terms of non-carcinogenic risk posed to the residents near the sites. When compared to probabilistic risk assessment, the CTE(central tendency exposure) cancer risk values of deterministic risk assessment were close to the mean values predicted by the probabilistic risk assessment. The RME(reasonable maximum exposure) values fell within the range of 95% to 99.9% estimated by the probabilistic risk assessment. Since the values of carcinogenic risk assessment were higher than $10{\times}10^{-6}$, further detailed monitoring and refined risk assessment for benzene may be warranted to estimate more reliable and potential inhalation risks to receptors near the industrial complexes.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.441-447
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• 1999

Changes in flavor characteristics of roasted coffee in 6 package models during storage were investigated by GC/MS analysis and sensory evaluation to establish the criteria of the shelf-life of the roasted coffee in three flavor quality-'fresh', 'satisfying' and 'minimally acceptable' levels. In direct headspace method of GC/MS, 47 volatile compounds were analyzed and the light volatile compounds were reduced sharply at initial stage of storage and faster in the package with air. The correlation between % retention of 2,3-butanedione and overall aroma of roasted coffee showed good linear-relation, of which correlation coefficient (R) were from 0.999 to 0.904 depending on package models, indicating that 2,3-butanedione would be an index chemical for evaluating the freshness of roasted coffee. In sensory evaluation of 6 package models during storage, roasted whole beans (RB) and roasted and ground (RG) coffee in air-package were preserved in 'fresh quality' for $0.5{\sim}1$ week, 'satisfying quality' for $2{\sim}3$ weeks and 'minimally acceptable quality' for 12 weeks, while roasted whole beans in valve-package and roasted and ground coffees in vacuum-package, nitrogen-package and oxygen absorbent-package were preserved in 'fresh quality' for $2{\sim}4$ weeks, 'satisfying quality' for $12{\sim}24$ weeks and 'minimally acceptable quality' for 52 weeks. The oxygen absorbent-package was slightly less effective than other three methods.

• Journal of the Korean Data and Information Science Society
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• v.27 no.1
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• pp.67-74
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• 2016

Due to the character of the climate of Korea, the pavement of a road is Influenced by freezing in winter season and thawing in thawing season. In the last few years, several articles have been devoted to the study to minimize the damage of freezing and thawing action. The purpose of this paper is to identify appropriacy of factors that influence road pavement thickness. We conduct the decision tree analysis on the field data of road pavement. The target variable is 'Frost penetration'. This value was calculated from the temperature data. The input variables are 'Region', 'Type of road pavement', 'Anti-frost layer', 'Month' and 'Air temperature'. The region was divided into 9 regions by freezing index $350{\sim}450^{\circ}C{\cdot}day$, $450{\sim}550^{\circ}C{\cdot}day$, $550{\sim}650^{\circ}C{\cdot}day$. The type of road pavement has three-section such as area of cutting, boundary area of cutting and bankin, lower area of banking. As the result, the variables that influence 'Frost penetration' are Month, followed by anti-frost layer, air temperature and region.

• Journal of the East Asian Society of Dietary Life
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• v.13 no.2
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• pp.136-144
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• 2003

This study was conducted to investigate the effect of 0.5% calcium lactate(CaL) on the fermentation of dough and quality and shelf-life of bread. Calcium lactates(CaL-A and CaL-P) were prepared from ash of black snail which contained shell and tissue together(ABS) and powder of the snail(PSB). pH of dough with the CaLs were higher than that of the control md, volume of the dough, loaf volume of bread were lower than those of the control products. But the volumes were almost the same when the pH of the dough were adjusted to pH 5.5. Mean calcium contents of treated bread (39.36~49.70 mg/100 g) were higher than that of control products(13.43 mg/100 g). There was no difference in Hunter $L^{*}$, $a^{*}$, $b^{*}$ values between the control and the treated group. Hardness and gumminess of CaL-A treated bread were the highest, but springiness and cohesiveness were the lowest. All the attributes showed no difference in case of pH adjustment(pH 5.5). The smaller pore and larger air cell with rough surface were observed in the CaL treated bread by SEM analysis. Sensory scores of CaL treated bread showed relatively lower values than those of the control products, but the scores increased by pH adjustment. The shelf-life of bread with CaL-P and CaL-A at 2$0^{\circ}C$ were 4 and 3 days, respectively, while that of the control group 1 day.day.y.

• Korean Journal of Optics and Photonics
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• v.11 no.5
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• pp.323-329
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• 2000

In this study we have calculated an ideal complex refractive index of a TiN trim used in a layer of anl1reilecnon (I\R) coatmg, [air$ISiO_2ITiNIglass$] in the visible. Also we simulated the rellectance of lwo-layer AR coating by varying the thicknesses of TiN and $SiO_2$ layers, respecl1vely. The simolation results show that we can controllhe lowest reflectance and AR band of tile AR coating. The TIN fihns were fabricated by a RF magnetron sputtering apparalus. The chemical, structural and electrical properties of TiN fih11S were inveshgated by the Rutherford backscattering spech'oscopy (RBS), atomic force microscope (AFM) and 4-point probe. The optical properlies were inve,tigated by the spectrophotometer and vanable angle spectroscopic ellipsometer (VASE). The smface roughness of TiN flhns \vas $9~10\AA$. TIle resistivity of TiN films was TEX>$360~730\mu$\Omega $ cm. The ,toichlOllletry of TiN film was 1'1: O:N = I: 0.65 :0.95 and ilic oxygen wa~ found on ilie smface. With these experimental and simu]al1on resulLs, we deposited duo: two-layer AR coating, [air$ISiO_2ITiNIglass$] and the refleClance was under 0.5% ill the regIOn of 440-650 run. 0 run.