• 아태비즈니스연구
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• 제9권4호
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• pp.157-180
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• 2018

This paper empirically analyzes how working conditions of employees and executives affect Korean companies' survival. To this end, a survival analysis based on the accelerated failure time model is conducted from the end of December 2012 to the end of September 2018 on the 2012 year-end financial data for corporations whose common stocks have ever been listed either in the KOSPI market or in the KOSDAQ market with fiscal year ending at the end of December. The analysis shows that the average wage level per employee and the number of executives relative to the number of employees threaten while the average duration of service for female employees prolongs firm survival. Here, the average wage level per employee has turned out to worsen firm survivability regardless of the gender of employees in question while the average duration of service improves firm survivability only in case the employees are female: the average duration of service for male employees or the entire employees has turned out not to have any statistically significant influence on firm survival. The average compensation per executive and the percentage of temporary employees have turned out not to have any statistically significant influence on firm survival while the percentage of female employees has shown statistically significant positive influence on firm survival in some, although not all, models employed in our study. These results are expected to be a good reference in the course of our reaching agreements regarding the improvement of working conditions either between firms and employees or among the members of the entire society.

• 한국결정성장학회지
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• 제31권3호
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• pp.127-136
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• 2021

This paper is dedicated to numerical simulation for diffusion-advective convection in a square cavity during physical vapor transport of Hg₂Br₂. Flow characteristics of the temperature difference between the source and crystal regions, 50℃ (300℃ → 250℃), partial pressures of component argon of 20 Torr and 100 Torr are investigated and presented as velocity vectors and streamlines, isotherms and iso-mass concentrations contours. Moreover, alterations of average Nusselt and average Sherwood numbers with (a) the source and crystal regions, (b) the pressures of component argon of 20 Torr and 100 Torr are analyzed and addressed in details. Both average Nusselt and average Sherwood numbers are seen to decrease with the increasing values of the partial pressures of component argon. Also, it is found that for the two different partial pressures of component argon, average Nusselt numbers at the source region are greater than at the crystal region, and inversely, average Sherwood numbers at the crystal region are greater than the source region by a factor of 3.

• 구강회복응용과학지
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• 제18권4호
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• pp.235-249
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• 2002

This study was accompolished to analyze and compare the number and area of the occlusal contact points in healthy volunteers and athletes with normal occlusion. Before the study, 89 athletes(sports career:8.6 years, average age 20) at Kyung Hee University were selected, and survey was accomplished for athlete's recognition about sports dentistry. For this study, 15 athletes(13 amles and 2 females with average age 20) and 21 healthy volunteers(14 mles and 7 females with average age 20.09) at Kyung Hee University were selected. The visual display acquired by scanning of occlusal record in maximal intercuspation was converted into 16 gray value image. Then, using computer program(J & Lee Occlusal Analyser), the pixel which was in definite range of the gray value was recognized, and the numbers of recognized pixel were calculated to area. The results were as follows : (1) On the survey about sports dentistry, 28% of 89 athletes didn't agree that human occlusion may be important, and 30% didn't have any idea of the influence of human occlusion during their sports activities. (2) The average numbers of total occlusal contact points were 31.05 in control group, and 34.67 in athlete group. The average area of total occlusal contacts was $100.25mm^2$ in control group, and $127.78mm^2$ in athlete group. (3) In control group, the average numbers of occlusal contact points were revealed in order as follows; the first molar(8.48), the second molar(8.24), the second premolar(4.71), the lateral incisor(2.90), the first premor(2.43), the central incisor(2.19), and the canine(2.1). The least average in canine(2.1) was similar to the average(2.19) in central incisor and (2.09) in lateral incisor. In athlete group, the average numbers of occlusal contact points were revealed in order as follows; the first molar(8.87), the second molar(8.47), the second premolar(5.60), the canine(3.80), the lateral incisor(3.33), the first premolar(2.67), and the central incisor(1.93). (4) In control group, the average areas of occlusal contact surface were revealed in order as follows; the first molar($39.47mm^3$), the second molar($37.54mm^3$), the second premolar($9.54mm^3$) the first premolar($6.18mm^3$), canine($3.49mm^3$), the central incisor($2.76mm^3$), and the lateral incisor($1.28mm^3$). In athlete group, the average areas of occlusal contact surface were revealed in order as follows; the first molar($44.11mm^3$), the second molar($40.69mm^3$), the second premolar($16.50mm^3$), the first premolar($9.39mm^3$), the canine($5.08mm^3$), the lateral incisor($3.7mm^3$), and the central incisor($2.25mm^3$). (5). With aging in both control and athlete group, there was a decreasing tendancy in average number of occlusal contact point, and was an increasing tendancy in average area of occlusal contact surface. In comparison at each age, both the numbers and area of occlusal contact were greater in athlete group than in control group. It was not significant in the numbers of occlusal contact points beween athlete and control group(p>0.1), but significant in the area of occlusal contact surface(p<0.05). (6) In comparision as to the kind of sports(Gymnastics:2, Rugby:3, Soccor:5, Ice hocky:5), the numbers of occlusal contact points were the most in ice hocky, and the area of occlusal contact surface was the greatest in gymnastics. With increasing a career in athlete group, there was a decreasing tendancy in average numbers of occlusal contact points, and was an increasing tendancy in average area of occlusal contact surface.

• 한국환경보건학회지
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• 제7권1호
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• pp.21-31
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• 1981

This survey was carried out to investigate the temperature, pH value, nitrogen (ammonia, nitrite, nitrate), turbidity, color, chloride ion, $KMnO_4$ consumed, and hardness as chemical analysis of the tap water in Seoul city area during the period from September to Octobor, 1979, and to observe the differences among the values by the distance from the water purification plant and by the district supplied tap water from-the each water purification plant. The results obtained were as follows: 1) An average of the water temperature was $19.8\pm 0.2\circ$C. 2) An average of pH was $7.18\pm 0.02$. The difference among each district was statistically significant (p<0.01), but it was not observed among each distance. 3) An average of turbidity was $1.25\pm 0.12$ ppm. The difference among each district was highly significant (p<0.01), respectively, but not among each distance. 4) An average of color was $1.43\pm 0.16$ ppm, and there were statistically significant differences by the distance and by the district (p<0.01). 5) An average of ammonia nitrogen was $0.022\pm 0.005$ ppm. The differences among each distance, and district were statistically significant (P<0.01). 6) An average of nitrite nitrogen was $0.0050\pm 0.0013$ ppm, and the difference among each distance was highly significant (p<0.01), respectively, and each district showed statistical significance (p<0.01). 7) An average of nitrate nitrogen was $0.82\pm 0.08$ ppm. The difference among each district was significant (p<0.05), and each distance showed high significance (p<0.01). 8) An average of $KMnO_4$ consumed was $3.73\pm 0.16$ ppm, and the difference among each district was significant (p<0.05), but it was not observed among each distance. 9) An average of chloride ion was $8.56\pm 0.28$ ppm, and the difference among each district was higly significant (p<0.01), respectively, but it was not observed among each distance. 10) An average of hardness was $40.69\pm 1.17$ ppm, and there was statistically significant difference by each district (P<0.01), but not by distance. 11) The interrelation between temperature and pH of the tap water revealed the negative correlation from the coefficient of it as showed r=-0.6073 and p<0.01. 12) Except water temperature, there were negative correlationships between pH and other water qualities. 13) Correlation coefficients of $KMnO_4$ comsumed and ammonia nitrogen, nitrite nitrogen were statistically significant but that of $KMnO_4$ consumed and nitrate nitrogen showed no statistical correlationship. 14) Ammonia nitrogen seems to have high correlationship with nitrite nitrogen(r= +0.6669), but not with nitrate nitrogen. 15) Nitrate nitrogen seems to have statistically significant correlationship with nitrite nitrogen (r=+0.4959), but not with ammonia nitrogen. 16) The interrelation between chloride ion and hardness of the tap water revealed positive correlation from the coefficient of it as showed as r=+0.4888 and p<0.01.

• 환경위생공학
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• 제18권4호
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• pp.24-35
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• 2003

Recent epidemiologic studies revealed that the concentration of air pollutants and fine particulated matter have some effects on health status and are associated with increased mortality and morbidity. The purpose of this study was to characterize background mass concentration of fine particle (PM2.5) and metallic composition from September 2001 to August 2002 in comparison with a medium city, Asan and metropolitan city, Seoul. Conclusively, proper management for fine particles was required in a medium city, Asan, considering the concentrations of metallic elements in fine particles in Asan were relatively higher than those in Seoul. The results were as followed. 1. Average mass concentrations of fine particles in Asan and Seoul were 37.70(${\pm}18.41{\;}{\mu}g/\textrm{m}^3$) and 5.83(${\pm}38.50$) ${\mu}g/\textrm{m}^3$, respectively. When the weather conditions were classified as normal and yellow-sand, measured average mass concentrations of fine particles in yellow-sand weather condition was significantly higher than those of normal weather condition in both cities (p<0.05). 2. Depending on seasons, measured average mass concentrations of fine particles in Asan and Seoul in spring were 47.76(${\pm}19.07$) ${\mu}g/\textrm{m}^3$m and 61.53 (${\pm}4.37$) ${\mu}g/\textrm{m}^3$, respectively. In summer, the average mass concentrations of fine particles in Asan and Seoul were 29.44(${\pm}9.85$) ${\mu}g/\textrm{m}^3$ and 25.42(${\pm}8.10$) ${\mu}g/\textrm{m}^3$, respectively. Especially, the concentration was the highest in spring and the lowest in summer among four seasons. 3. Average concentrations of manganese(Mn), iron(Fe), chromium(Cr), cadmium(Cd), lead(Pb) and silicon(Si) in fine particles in Asan were significantly higher in Seoul (p<0.05). Average concentration of Si in fine particle in Asan was statistically higher than that of Seoul during yellow -sand condition (p<0.05). 4. Considering the characterization of four seasons, average Pb concentration of fine particle in Asan is significantly higher than that of Seoul in spring(p<0.01). In summer, average Mn and Cr concentrations of fine particle in Asan is higher than those of Seoul (p<0.05). Average Mn, Fe. Cr and Si concentrations in fall (p<0.05), and average Mn, Fe, Cr, Pb, and Si concentrations in winter (p<0.05) in Asan were higher than those of Seoul, respectively. 5. Mass concentrations of each Mn, Fe, Cd and Si in fine particles were significantly correlated with both cities. In normal weather condition, Mn, Cu and Si concentrations are statistically significant in Asan, while Mn, Fe, Cu and Si concentrations are statistically significant in Seoul. Mn, Fe and Si concentrations in both cities were statistically significant during yellow-sand weather.

• 대한간호학회지
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• 제28권4호
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• pp.941-957
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• 1998

The purpose of this study was to use meta-analysis to analyze result of 17 studies which investigated the effects of integrated programs, and 11 studies which examined the effects of exercise programs on pain, depression, and disability. The 28 studies analyzed in this work were selected from the following sources. MEDLINE Search, bibliographies of related studies, main academic journals of nursing in Korea, and journals on arthritis issues. For the analysis of the data, homogeniety of effect sizes which were calculated based on data in the 28 studies was tested and its average effect size was computed by using meta analysis software package which was developed by Song(1992, 1998). The results can be summarized as follows : 1) Homogeneity tests were conducted on integrated programs on pain. In the prelimiary homogeneity tests on effect size of all 17 studies, no homogeneity was found. When homogeneity tests on the effect size of the remaining 15 studies were performed, excluding two studies which had extremely larger effect size compared to other studies, the 15 studies were found to be homogeneous(Q=16.38, p=.23). The obtained average effect size, D(Mean Standardized Difference Between Means), was .25. When homogeneity tests on effect size on pain was conducted for the excercise programs, effect size for all nine studies were found to be homogeneous (Q=7.42, p=.49) and the average effect size D=.30. Therefore, Hypothesis 1 was rejected from the results, that an average effect size of the integrated programs on pain was not significantely different from that of the exercise programs on pain. 2) Since only two studies investigated the effect of exercise programs on depression, comparison between the average effect size of integrated programs and that of exercise programs on depression could not be conducted, and hypothesis 2 could not be tested. Thereby, only the average effect size of integrated programs on depression was obtained. Eight studies were tested to be positive on the homogeneity of effect sizes(Q=18.31, p=.02) at $\alpha$<.01 and its average effect size was D=.11. 3) For the analysis of integrated program on disability, 13 studies, except for four which had an extremely large effect size compared to the others were found to be homogeneous at $\alpha$<.01 (Q=22.30, p=.04) and the average effect size on disability was D=.16. For analysis of the exercize programs on disability, eight studies, except for one which had an extremely large effect size compared to others, were found to be homo geneous(Q=7.87, p=.34) and the average effect size on disability was D=.60. Therefore, Hypothesis 3 was accepted from the results that an average effect size of exercise programs on disability was significantly larger than that of integrated programs on disability.

• 한국환경과학회지
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• 제17권7호
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• pp.755-765
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• 2008

To investigate correlation between the distribution of marine bacteria and environmental characteristics in the surface sediments of Kamak Bay, chemical oxygen demand(COD), acid volatile sulfide(AVS), ignition loss(IL), total organic carbon(TOC), and total organic nitrogen(TON) were measured and analyzed at 7 stations in winter and summer. In winter, COD and AVS ranged from 13.45 mg/g to 30.06 mg/g(average: 23.58 mg/g) and from 0.03 mg/g to 1.04 mg/g(average: 0.63 mg/g), respectively. IL, TOC, and TON ranged from 8.03% to 11.41%(average: 9.41%), from 1.17% to 2.10%(average: 1.62%), and from 0.09% to 0.18%(average 0.15%), respectively. In summer, COD, AVS, IL, TOC, and TON ranged from 14.06 mg/g to 32.19 mg/g(average: 24.71 mg/g), from 0.03 mg/g to 1.11 mg/g(average: 0.66 mg/g), from 9.00% to 12.15%(average: 10.96%), from 1.27% to 2.12%(average 1.77%), and from 0.12% to 0.19%(average: 0.16%), respectively. These values were relatively higher than those in winter. Kamak Bay had high C/N ratio that might be resulted from the input of terrestrial sewage and industrial wastewater. The number of marine viable bacteria was $8.9{\times}10^4\;cfu/g$ in winter and $9.7{\times}10^5\;cfu/g$ in summer. The most abundant species were Pseudomonas spp., Flavobacterium spp., and Vibrio spp, in the surface sediments of Kamak Bay. It was found that the concentration of organic matters and viable bacterial cells in the inner part were relatively higher than those in the outer of Kamak Bay. The distribution of viable bacterial cells was closely influenced by environmental factors.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.289-289
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• 2017

The climate change impact has facilitated double cropping system on maize production in Korea. The objectives of this study were to investigate the chemical composition changes according to the sowing dates on double cropping in 8 dent type, 2 intermediate type, and 4 semiflint type of Korean maize (Zea mays L.) hybrids and evaluate its antioxidant characteristics. Fourteen maize hybrids were sown on April 5 and July 5 of 2015. The average crude protein contents in dent and semiflint type maize sown on April 5 were higher than those sown on July 5 (p<0.05). There was no significant difference in average of total amino acid contents in all types of maize according to the sowing dates. Major amino acid in maize hybrids were glutamic acid followed by proline, alanine, and aspartic acid, which has no significant difference according to the sowing dates. The average crude fat contents in semiflint and intermediate type maize sown on April 5 were higher than those sown on July 5 (p<0.05). The average composition of saturated fatty acid in dent type maize sown on April 5 was higher than those sown on July 5. However, the average unsaturated fatty acid composition showed the opposite result (p<0.05). Fatty acids were mainly composed of linoleic acid (C18:2) and oleic acid (C18:1) in maize hybrids. The average oleic acid percentage of dent and semiflint type maize sown on April 5 were higher than those sown on July 5, while the average linoleic acid was lower. The average amylose content of all types of maize sown on April 5 was higher than those sown on July 5. On the other hands, the average carotenoid contents had the opposite result (p<0.05). There were no significant differences in total average of polyphenol contents and DPPH and ABTS radical scavenging activities in all types of maize based on the sowing date. Total polyphenol contents had positive correlation with DPPH (r=0.33, p<0.01) and ABTS (r=0.50, p<0.0001) radical scavenging activities. In conclusion, the kernel composition affects maize quality. These data are useful for maize breeding program and cultivation and food processing industry.

• Journal of the Korean Data and Information Science Society
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• 제24권3호
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• pp.543-555
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• 2013

이 연구는 프로골프대회에서 기록되는 중요변인들 (드라이브거리, 페어웨이안착율, 그린적중율, 센드세이브율, 리커버리율, 평균퍼팅수)이 평균타수에 미치는 영향력에 대해 집단 간 차이를 분석하였다. 구체적으로 미국남자프로골프협회 (PGA), 미국여자프로골프협회 (LPGA), 한국남자프로골프투어 (KGT), 그리고 한국여자프로골프투어 (KLPGT)에서 측정, 공개하는 자료를 통해 PGA, LPGA, KPGA, KLPGA 집단 간에 중요변인들이 평균타수에 미치는 경로에 유의한 차이가 있는지를 검증하였다. 그 결과 PGA와 LPGA 모형 간에 드라이브거리와 그린적중율이 평균타수에 미치는 경로가 p <.05 수준에서 통계적으로 유의한 차이가 있는 것으로 나타났으며, KPGA와 KLPGA 모형 간에는 드라이브거리, 리커버리율, 그리고 평균퍼팅이 평균타수에 미치는 경로가 유의한 차이가 있는 것으로 나타났다. 또한 PGA와 KPGA 모형 간에 드라이브거리, 리커버리율, 그리고 평균퍼팅이 평균타수에 미치는 경로가p <.05 수준에서 통계적으로 유의한 차이가 있는 것으로 나타났으며, LPGA와 KLPGA 모형 간에는 모든 경로에서 p >.05 수준에서 통계적으로 유의한 차이가 없는 것으로 나타났다. 이 연구 결과는 남녀 국내 투어와 미국 투어의 골프 경기력의 구조 특성을 이해하는데 필요한 기초자료로 활용 할 수 있을 것이며 향후 투어 진출을 위한 유의한 정보가 될 수 있을 것이다.

• 지질공학
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• 제30권2호
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• pp.161-173
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• 2020

본 연구는 세계지질공원인 무등산국립공원 내 주상절리대의 공학적 특성을 살펴보고 위한 것으로서, 대상 암석인 무등산응회암의 물리·역학적 성질 파악, 주상절리 풍화정도 산정, 그리고 주상절리 내 균열거동 모니터링 등을 실시하였다. 무등산응회암의 물리적 성질은 평균 공극률의 경우 1.02%, 평균 흡수율은 0.38%, 평균 비중은 2.69 g/㎤, 그리고 평균 종파속도는 4,948 m/s로 나타났다. 역학적 성질의 경우 평균 일축압축강도는 337 MPa, 평균 탄성계수는 68 GPa, 평균 포아송비는 0.29, 평균 점착력은 41.3 MPa, 평균 마찰각은 62.8°로 나타났다. 실버슈미트해머 평균 반발경도 Q값은 49.3이며, 이를 일축압축강도로 환산하면 70.5 MPa로 신선한 일축압축강도의 약 21%에 해당되었다. 그리고 입석대 주상절리 3개 블록에 대한 균열 모니터링 측정 결과, 균열 거동은 블록 모두에서 1 mm 이하로 나타나 주상절리 내 균열 거동은 현재까지 거의 발생하지 않은 것으로 판단된다.