• 한국환경과학회지
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• 제27권7호
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• pp.543-554
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• 2018

From November 2013 to December 2016, ambient fine particulate matter ($PM_{2.5}$) was sampled in the downtown area of Jeju City, South Korea, which has seen rapid urbanization. The atmospheric concentrations of elements were measured in the $PM_{2.5}$ samples. This study focused on Cd, Cr, Cu, Mn, Ni, Pb, As, Sb, Sn, V, and Zn. The concentrations of Al, Na, K, Fe, Ca, Mg, Sr, and La were also obtained for reference. The objectives of this study were to examine the contributions of these elements to $PM_{2.5}$ concentrations in downtown Jeju City, and to investigate the inter-element relationships and the elemental sources by using enrichment factors and principal components analysis (PCA). A composition analysis showed that the 19 elements constituted 6.65 % of the $PM_{2.5}$ mass, and Na, K, Al, Fe, Ca, Mg, and Zn constituted 98 % of the total ion mass. Seasonal trend analysis for the sampling period indicated that the concentrations of the elements increased from November to April. However, no substantial seasonal variations were found in the concentrations of the elements. The composition ratios of some elements (Cu/Zn, Cu/Cd, Cu/Pb, V/Ni, and V/La) were found to be out of range when compared to the literature from other urban areas. The ratios between the elements and the PCA results showed that local contaminant sources in Jeju City rarely influence the composition of $PM_{2.5}$. This suggests that the major sources of $PM_{2.5}$ in Jeju City may include long-range transport of fine particulate matter produced in other areas.

• 한국환경보건학회지
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• 제36권2호
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• pp.108-117
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• 2010

In this study, ambient particulate matter ($PM_{2.5}$ and $PM_{10}$) levels were measured and their chemical and physical properties were characterized. Two sites in Gwangju were sampled once a month from December 2008 to November 2009. The annual mean concentrations of $PM_{2.5}$ and $PM_{10}$ were $26.9\;{\mu}g/m^3$ and $46.3\;{\mu}g/m^3$, respectively, in Nongseongdong and $26.1\;{\mu}g/m^3$ and $44.8\;{\mu}g/m^3$, respectively, in Duam-dong. $PM_{2.5}$ levels were 1.8 times higher than the USA Environmental Protection Agency (EPA) national ambient air quality standard for $PM_{2.5}$ ($15\;{\mu}g/m^3$). The average $PM_{2.5}/PM_{10}$ ratio of 0.58 suggested that $PM_{2.5}$ is a significant component of the ambient particle pollution. The order of concentration of metallic elements in $PM_{2.5}$ and $PM_{10}$ was Si > Al > Fe > Zn > Pb > Cu > Mn. Cd was not detected. The earth crustal enrichment factors for Cr, Cu, Pb and Zn in $PM_{2.5}$ were higher than those in $PM_{10}$. When the earth crustal enrichment factors for Cr, Cu, Pb and Zn were higher than 10, this suggested influence from anthropogenic sources. The soil contribution ratios for $PM_{2.5}$ and $PM_{10}$ were 11.3% and 16.4%, respectively, and were higher in the fall and winter. Anions (${SO_4}^{-2}$, ${NO_3}^-$, and $Cl^-$) comprise 28.7% of $PM_{2.5}$ and 21.4% of $PM_{10}$. The correlation coefficient of Zn-Fe, Mn-Cu, Fe-Cu and Fe-Mn in $PM_{2.5}$ was high in the sampling sites, and metallic elements were primarily from anthropogenic sources such as fuel combustion and vehicle emissions.

• 한국습지학회지
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• 제13권2호
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• pp.243-263
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• 2011

시화호 형도 근처 조간대(帶, intertidal zone) 지역 갯벌의 퇴적환경을 알아보기 위해 10개 정점 표층 및 2개 정점 주상퇴적물에 대한 입도, 함수율, 휘발성산화합물(Acid Volatile Sulfide; AVS), 총유기탄소(Total Organic Carbon; TOC) 및 중금속(Al, Fe, Mn, Cu, As, Pb, Zn, Ni, Cd 및 Cr) 항목에 대해 분석 하였다. 표층 퇴적물은 대체로 분급이 불량(분급도, 0.60~2.31${\phi}$)한 sandy Silt, slightly gravelly muddy Sand, silty Sand 및 Sand 등의 퇴적상으로 구분되며, 평균입도는 2.95~6.00${\phi}$로 극조립 실트(Silt)에 해당한다. 표층 퇴적물의 Al 함량은 1.54%, Fe은 1.75%, Cu는 9.1ppm, As는 1.1ppm, Pb은 18.8ppm, Ni은 11.0ppm, Cd은 0.02ppm 그리고 Cr은 30.1ppm으로 측정되었으며, 주상 퇴적물 또한 미국해양대기청(National Oceanic and Atmospheric Administration; NOAA) 기준의 ERL(Effective Range Low, 저서생물에 독성을 보이는 초기 10% 농도)을 초과하지 않았다. 주상퇴적물의 과잉 방사능 납($^{210}Pbex$)의 분포를 통해 퇴적률을 추정한 결과, 급격한 퇴적물의 다량유입에 의해 수직적으로 방사능(activity)이 유사한 값을 나타내고 있어 정확한 퇴적률(apparent sedimentation rate)은 추정할 수 없었다. 그러나 2개 코어 상부 35cm 에서 퇴적물의 급격한 유입 및 환경적 영향등으로 금속 농축계수(Enrichment factors; EF) 계산값은 비교적 높게 나타났다.

• 유통과학연구
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• 제12권7호
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• pp.13-21
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• 2014

Purpose - This study reveals antecedent factors to help develop expressway rest areas in which employees were exposed to inferior environments, using Hackman and Oldham's Job Characteristics Theory. Research design, data, and methodology - The survey was conducted on 148 expressway rest area employees in Gyeonggi-do. After excluding questionnaires with invalid responses, 141 questionnaires were analyzed. Results - The sub-factors of job characteristics had a positive influence on the organizational commitment of employees, and organizational commitment had a positive influence on organizational citizenship behavior (OCB). Further, the results of mediation effects showed that organizational commitment and self-leadership were partially mediated. Finally, the results of the moderation effect of self-leadership showed that self-leadership was thought to be vital to let members endeavor to promote the competitiveness of expressway rest areas. Conclusions - The expressway rest area company needed to design jobs to let employees be self-motivated, productive, positive, responsible, and aspirational; job redesign, including job enrichment and job enlargement can be considerably helpful for affirmative influence.

• The Journal of Asian Finance, Economics and Business
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• 제8권3호
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• pp.99-110
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• 2021

This study aims to examine empirically the industry and economic fundamental factors that affect the stock prices of the leading palm oil company in Indonesia. The dynamics of stock price are analyzed using the autoregressive distribution lag (ARDL) model both for symmetric and asymmetric effects. The data used in this study are monthly data for the period from 2008:01 to 2020:03. In the long run, the company stock price moves in line with the competitor company stock price at the current time. The palm oil price has a positive effect on the stock price. Meanwhile, inflation negatively affects the stock price in the short run. The estimated equilibrium correction coefficient indicates a reasonably quick correction of the distortion of the stock price equilibrium in monthly dynamics. However, fundamental factors have asymmetric effects, especially the response of stock price when these factors decrease rather than increase in the short run. Stock prices that are responsive to declines in fundamental performance should be of particular concern to both investors and management in their strategic decision making. The results of this study will contribute to the enrichment of literature related to stock prices from the viewpoint of economic analysis on firm-level data.

• 한국대기환경학회지
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• 제19권2호
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• pp.145-156
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• 2003

The atmospheric aerosols collected at the 1100 site located in Mt. Halla have been analyzed to investigate their compositions and chemical characteristics . The average concentrations of water-soluble cations were in the order of N $H_{4}$$^{+}$ > $Ca^{2+}$ > N $a^{+}$ > $K^{+}$ > $Mg^{2+}$ during the spring, showing high increase of $Ca^{2+}$ concentration with the value of 0.60 $\mu\textrm{g}$/ $m^3$, and N $H_{4}$$^{+}$> N $a^{+}$> $K^{+}$> $Ca^{2+}$ > $Mg^{2+}$ during the other seasons. The average concentrations of anions have shown in the order of S $O_{4}$$^{2-}$ > N $O_{3}$$^{[-10]}$ >C $l^{[-10]}$ for all seasons, and S $O_{4}$$^{2-}$ and N $O_{3}$$^{[-10]}$ had higher concentrations in spring with the values of 4.84 $\mu\textrm{g}$/ $m^3$ and 1.08 $\mu\textrm{g}$/ $m^3$, respectively. From the analytical data of size-segregated particles by cascade impactor sampling, the components of N $H_{4}$$^{+}$, S $O_{4}$$^{2-}$, N $O_{3}$$^{[-10]}$ and $K^{+}$ were distributed mainly in fine particles, but $Ca^{2+}$, N $a^{+}$, $Mg^{2+}$ and C $l^{[-10]}$ were included mostly in coarse particles. The correlation coefficients of nss-S $O_{4}$$^{2-}$/N $H_{4}$$^{+}$, nss-S $O_{4}$$^{2-}$/ $K^{+}$ and N $O_{3}$$^{[-10]}$ /nss-C $a^{2+}$ showed quite high values with 0.871, 0.857 and 0.654, respectively Based on the study of enrichment factors, it is considered that N $a^{+}$, $Mg^{2+}$, C $l^{[-10]}$ and $Ca^{2+}$ components were delivered from oceanic and soil sources, but S $O_{4}$$^{2-}$, N $O_{3}$$^{[-10]}$ and N $H_{4}$$^{+}$ might have other source origins. The factor analysis study showed the aerosol at the 1100 site was influenced mainly by anthropogenic factors, followed by oceanic and soil factors. followed by oceanic and soil factors.

• International Journal of Knowledge Content Development & Technology
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• 제8권3호
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• pp.29-40
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• 2018

This paper discussed motivation, some theories of motivation and motivation of library personnel. The most important aspect of any organization is its workforce. Motivation arouses, energizes, influences and sustains behaviour and performance of employees. Motivating factors include extrinsic factors which pertain to the conditions under which a job is performed and intrinsic motivators which contribute to job satisfaction and subsequently increase productivity. Two levels of motivation were identified in the library: the need-factor motivation and the profession-related motivation. Need-factor motivation is well-pronounced in the lower cadre of library staff such as library assistants, clerical staff, and porters who set their priority on economic needs. The profession-related motivation occurs among professionally trained librarians whose motivation hinges self-fulfillment derived from professional growth and development. Other motivating factor in the library is job design which includes job rotation, job enlargement, and job enrichment. Job design specifies the contents or methods of any job in such a way that various requirements of a job can be effectively satisfied. Adequate motivation of library employees lies with the managers because they generally control work distribution, freedom and autonomy, work challenge Remove, staff development and training, and advancement opportunities. The managers are urged to create enabling environment to ensure improved commitment, satisfaction, and productivity of employees in the library.

• Nuclear Engineering and Technology
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• 제49권1호
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• pp.6-16
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• 2017

This study presents a coolant void reactivity analysis of Canada Deuterium Uranium (CANDU)-6 and Advanced Canada Deuterium Uranium Reactor-700 (ACR-700) fuel lattices using a Monte Carlo code. The reactivity changes when the coolant was voided were assessed in terms of the contributions of four factors and spectrum shifts. In the case of single bundle coolant voiding, the contribution of each of the four factors in the ACR-700 lattice is large in magnitude with opposite signs, and their summation becomes a negative reactivity effect in contrast to that of the CANDU-6 lattice. Unlike the coolant voiding in a single fuel bundle, the $2{\times}2$ checkerboard coolant voiding in the ACR-700 lattice shows a positive reactivity effect. The neutron current between the no-void and voided bundles, and the four factors of each bundle were analyzed to figure out the mechanism of the positive coolant void reactivity of the checkerboard voiding case. Through a sensitivity study of fuel enrichment, type of burnable absorber, and moderator to fuel volume ratio, a design strategy for the CANDU reactor was suggested in order to achieve a negative coolant void reactivity even for the checkerboard voiding case.

• Genomics & Informatics
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• 제8권3호
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• pp.142-149
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• 2010

In recent years, genome-wide association (GWA) studies have successfully led to many discoveries of genetic variants affecting common complex traits, including height, blood pressure, and diabetes. Although GWA studies have made much progress in finding single nucleotide polymorphisms (SNPs) associated with many complex traits, such SNPs have been shown to explain only a very small proportion of the underlying genetic variance of complex traits. This is partly due to that fact that most current GWA studies have relied on single-marker approaches that identify single genetic factors individually and have limitations in considering the joint effects of multiple genetic factors on complex traits. Joint identification of multiple genetic factors would be more powerful and provide a better prediction of complex traits, since it utilizes combined information across variants. Recently, a new statistical method for joint identification of genetic variants for common complex traits via the elastic-net regularization method was proposed. In this study, we applied this joint identification approach to a large-scale GWA dataset (i.e., 8842 samples and 327,872 SNPs) in order to identify genetic variants of obesity for the Korean population. In addition, in order to test for the biological significance of the jointly identified SNPs, gene ontology and pathway enrichment analyses were further conducted.

• 한국건설관리학회논문집
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• 제17권2호
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• pp.90-98
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• 2016

고층 건설 프로젝트는 다양한 위험 요인이 있다. 주요 위험 요인은 시간 지연과 비용의 증가 등의 부정적인 결과이다. 따라서, 본 연구는 PROMETHEE 기법을 사용하여 초고층 건설공사 시공 단계에서의 위험 요인을 분석하였다. 이를 위해, 본 연구는 전문가 표적집단면접법(FGI)을 통해 위험 인자를 확인 하였다. 그리고 PROMETHEE는 초고층 건설공사 위험 분석을 위한 설정 평가기준으로 사용 하였다. 다음으로, 평가지표 계산의 기준은 PDRI에서 정의 레벨을 사용하여 구성하였다. 선호지수 및 평가 지표는 설문을 통해 규명되었다. 이러한 과정을 통해, PROMETHEE 기법을 이용하여 본 연구는 초고층 건설공사 시공 리스크의 중요도를 산정하였다. 그 결과, 높은 수준의 위험 요인은 다음과 같이 나타났다. 이것은 '재료 리프팅 운영 계획', '아웃리거 벨트 트러스 건설', '고층 건물의 기초 작업 계획'과 '고층 건물의 구조 개념을 고려'이다.