• 한국안전학회지
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• 제37권6호
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• pp.102-107
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• 2022

South Korea will soon be a super-aged society, as more than 20.6% of its population will be 65 years and older by 2025. As of 2022, 17.5% of the total population in South Korea is 65 years and older, which exceeds the set threshold for an aged society, where more than 14% of the population is 65 years and older. The proportion of older subway construction workers has increased. Aging workers and their work stress negatively impact their workability. A previous study demonstrated that the stress index measured using the uBioMacpa measurement device (Macpa stress index) had a significant correlation with work stress in South Korea. The device tests vascular health and measures stress levels via Macpa signal analysis. In this study, the pulse waves of subway construction workers were measured using uBioMacpa to identify their stress levels. The stress levels were analyzed by age, years of service, job position, employment type, and work type. Herein, these statistics could not be easily represented by a normal distribution; therefore, the Kruskal-Wallis test, a nonparametric statistical method, was used for the analysis of data. The results showed that age, job position, employment type, and working type affected the Macpa stress index and the stress levels of workers increased with age. In terms of job position, technical engineers were more stressed than other workers because of their poor working environment. In terms of employment type, daily-wage workers were more stressed than other workers. In terms of working type, tunneling, waterproofing, and construction scored the highest Macpa stress indexes without any significant difference, whereas earthworks scored the lowest. Based on the analysis of Macpa stress index, safety and health management plans were proposed to reduce the stress levels of workers. Moreover, a manual for efficient stress management must be developed for subway construction workers.

• Spatial Information Research
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• 제22권3호
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• pp.23-24
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• 2014

국토지리정보원에서는 실시간으로 정밀한 위치를 결정할 수 있도록 Network-RTK의 한 종류인 VRS 서비스를 2007년부터 제공하고 있다. 그러나 VRS 서비스는 실시간 측위를 수행하기 위해 통신장비를 이용하여 VRS 서버와 접속 상태를 항시 유지해야하며, VRS 서버의 성능에 따라 접속할 수 있는 사용자의 수가 한정되어 있다. 이러한 VRS 서비스의 문제점을 보완하기 위하여 국토지리정보원에서는 2012년 11월 1일부터 동시 접속자 수에 제한이 없는 단방향 통신기반의 FKP를 서비스 제공하고 있다. FKP 서비스의 실시로 인해 향후 많은 인원이 투입될 것으로 예상되는 공공측량 및 지적재조사 사업에 FKP 서비스의 활용이 증대될 것으로 판단되나, 이에 관한 연구가 미비한 실정이다. 따라서 본 논문에서는 공공측량 및 지적재조사 사업에 FKP 서비스 적용 가능성을 분석하기 위하여 다음과 같이 두 가지 경우로 나누어서 연구를 수행하였다. 첫째, 현재 FKP와 VRS는 망의 형태를 구성하는 기준국의 배치가 상이하므로 망 구성에 따른 FKP와 VRS의 정밀도 비교분석을 수행하였다. 둘째, FKP 서비스의 공공측량 및 지적재조사 사업 적용가능성 분석을 수행하기 위해 다양한 GNSS 수신환경의 데이터를 취득하여 Network-RTK 수평방향 및 표고산출 정밀도분석을 수행하였다. 첫 번째 실험의 분석결과 망 구성에 따른 측위 정밀도는 모두 관련규정의 허용정밀도를 만족하는 결과를 얻었다. 그러나 상이한 기준국을 운영할 경우에는 기준국과 이동국 사이의 기선거리가 멀어짐에 따라 측위 정밀도에 오차가 포함되는 것으로 판단된다. 두 번째 실험인 Network-RTK 수평방향 정밀도 분석결과 GNSS 관측수신환경이 좋은 통합기준점에서는 FKP 및 VRS 모두 허용정밀도를 만족하였다. 그러나 GNSS 관측수신환경이 좋지 않은 공공기준점 및 지적도근점에서는 FKP가 VRS보다 허용정밀도를 벗어나는 경우가 더 많이 발생되었다. FKP와 VRS의 표고산출 정밀도 분석결과에서는 VRS 측위방법 에서만 관련규정의 공공삼각점 3~4급 허용정밀도를 만족하였다. 분석결과 현재 FKP 서비스의 정밀도를 이용하여 공공측량 및 지적재조사 사업에 이용하기 위해서는 GNSS관측 수신환경이 양호한 개활지역에 한정하여 부분적용 해야 할 것으로 판단되며, 향후 FKP 정밀도 개선을 위해 추가적인 연구가 필요할 것으로 판단된다.

• 산업진흥연구
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• 제1권1호
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• pp.19-25
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• 2016

본 연구는 중소기업 근로자를 대상으로 업무 및 복지환경 등에 대한 만족도 현황을 파악하여 미흡한 사항은 개선을 통해 전반적인 만족도의 향상을 도모하는데 있다. 측정도구의 신뢰도를 검증하기 위해 신뢰도 분석을 실시한 결과, 모든 요인의 신뢰도 계수는 0.6 이상으로 다소 높은 것으로 나타났다. 관계 요인과 복지 만족도, 보상 요인과 복지 만족도를 제외한 모든 변수 간의 상관관계가 +0.2 이상 +0.8 미만으로 양의 상관관계가 있는 것으로 나타났다. 직무 요인, 관계 요인, 보상 요인이 직무 만족도와 복지 만족도에 미치는 영향을 알아보기 위해 직무 요인, 관계 요인, 보상 요인을 독립변수로 하고 직무 만족도와 복지 만족도 각각을 종속변수로 하여 다중회귀분석을 실시한 결과, 세 요인 중 직무 요인과 보상 요인, 두 요인이 직무 만족도에 유의한 영향을 미치는 것으로 나타났다. ${\beta}$값을 보면 직무 요인(.584), 보상 요인(.369) 순으로 직무 만족도에 미치는 영향이 큰 것으로 나타났다. 업무 및 복지환경 개선을 통하여 직원들의 만족도가 향상됨으로써, 업무에 적극적인 자세로 임하여 외부고객의 만족도에 긍정적인 영향을 미칠 것으로 기대된다.

• 한국산업보건학회지
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• 제32권1호
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• pp.21-30
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• 2022

Objectives: The purpose of this study is to suggest an optimal method by comparing the analysis methods of work environment measurement datasets including left-censored data where one or more measurements are below the limit of detection (LOD). Methods: A computer program was used to generate left-censored datasets for various combinations of censoring rate (1% to 90%) and sample size (30 to 300). For the analysis of the censored data, the simple substitution method (LOD/2), β-substitution method, maximum likelihood estimation (MLE) method, Bayesian method, and regression on order statistics (ROS)were all compared. Each method was used to estimate four parameters of the log-normal distribution: (1) geometric mean (GM), (2) geometric standard deviation (GSD), (3) 95th percentile (X95), and (4) arithmetic mean (AM) for the censored dataset. The performance of each method was evaluated using relative bias and relative root mean squared error (rMSE). Results: In the case of the largest sample size (n=300), when the censoring rate was less than 40%, the relative bias and rMSE were small for all five methods. When the censoring rate was large (70%, 90%), the simple substitution method was inappropriate because the relative bias was the largest, regardless of the sample size. When the sample size was small and the censoring rate was large, the Bayesian method, the β-substitution method, and the MLE method showed the smallest relative bias. Conclusions: The accuracy and precision of all methods tended to increase as the sample size was larger and the censoring rate was smaller. The simple substitution method was inappropriate when the censoring rate was high, and the β-substitution method, MLE method, and Bayesian method can be widely applied.

• 한국전산구조공학회논문집
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• 제32권1호
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• pp.65-73
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• 2019

선박의 생산 효율을 높이고 생산 주기를 단축하기 위해서는 건조 주기 동안에 효율적으로 선박 구성 요소의 정확도를 평가하는 것이 중요하다. 블록의 정도 관리는 선박 공정의 단축 및 비용 절감, 선박 품질 향상에 중요한 의미를 갖는다. 대형 조선소를 중심으로 이를 위한 시스템들이 개발되어 활용되고 있지만 일부 조선소에서는 블록 형상이나 크기에 따라 줄자나 추 등의 전통적인 측정도구나 광학 장비인 광파기를 사용하여 측정, 관리하고 있으며, 정도 관리 수행하는데 있어서 이러한 도구나 장비뿐만 아니라 필수적으로 측정 위치를 파악하기 위한 종이 도면과 측정 데이터를 기록하기 위한 장치를 병행하고 있다. 측정된 결과는 수기 입력 혹은 기록 장치를 통해 정도 관리 시스템에서 관리하게 된다. 측정 결과는 작업 환경 및 작업자의 숙련도에 따라 영향이 미치게 되며, 측정 결과 관리 측면에서도 측정 결과 작성 누락, 정도관리 시트 관리의 부재 등에 대한 인적 오류(human error)와 시스템 내 결과 데이터 입력으로 인한 이중 작업 시간 소요로 인한 효율 측면에서의 비용 손실이 발생한다. 본 연구에서는 기존 정도관리 수행에서의 작업 환경을 개선하기 위한 목적으로 블록 정도 및 블록 측정 위치를 종이 도면을 통해서 확인하던 과정을 증강현실 기술을 이용하여 실제 블록 위에 측정 정보를 가시화함으로써 정도관리 수행 시간을 단축하고 측정 장비와의 연동을 통해 정도관리 데이터를 효과적으로 관리할 수 있는 증강현실 기반의 스마트 정도관리 시스템을 제안하고, 제안한 시스템에 대해서 프로토타입 구현을 통하여 정도 관리에서의 적용 가능성을 검토하였다.

• 한국대기환경학회지
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• 제30권2호
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• pp.175-187
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• 2014

The subways play an important part in serious traffic problems. Almost seven million citizens a day are using subways as a means of traffic communication in the Seoul metropolitan city in 2012. However, the subway system is a semi-closed environment, so many serious problems occurred in subway stations and injured passengers' health. Platform screen doors (PSD) are expected to prevent negligent accident such as injury or death from falling and improve the air quality of the subway station. Installation of PSD at stations in Seoul metropolitan subway had been completed in December 2009. Consequently, the underground transportation system became a closed environment, so the air quality has improved the platforms, but it has deteriorated in the tunnels. Especially, the subway cabin has many doors, and the doors are frequently opened and closed. For this reason, the effect of door opening on subway cabin, dust flow inside the subway cabin. In this process, the maintenance work may influence the health of people who work underground, as well as that of subway users (passengers). In this study, we measured air quality inside and outside of the subway cabin line 2 in Seoul, Korea. This study focused on the investigation of Indoor Air Quality (IAQ) and measurement target pollutants are PM10, CO, $CO_2$, $NO_2$, $O_3$. It was found that levels of PM10, $CO_2$, and $NO_2$ inside subway cabin line 2 exceeded the Korea IAQ standard. Concentrations of PM10, $CO_2$, and $NO_2$ inside of the cabin are higher than outside of the cabin (Indoor Outdoor ratio is higher than 1.). Concentrations of CO, $O_3$ inside of the cabin are lower than outside of the cabin (Indoor Outdoor ratio is lower than 1.). There is a high correlation between $CO_2$ and passengers inside of the cabin and PM10 is only the weakest correlation with passengers. Therefore, it is important to find out the emission source of $NO_2$. The results of this study will be useful as fundamental data to study indoor air quality of a subway cabin.

• 한국대기환경학회지
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• 제15권4호
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• pp.403-415
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• 1999

To properly assess air pollution levels, application of quality assurance and quality control(QA/QC) is believed to be an essential step. In order to cope with such scientific principle, a field study was designed with an aim of comparing: 1) the methods of calibration for airborne pollutants and 2) the protocols developed for their measurements. Measurements were made at Han Yang University, Seoul during 29 May through 1 June 1998 under the management of the Division of Measurements and Analysis(DMA) of Korean Society for Atmospheric Environment(KOSAE). In this work, we report our results of intercomparative measurements on several gaseous criteria pollutants that were investigated mainly by the two institutes-Seoul National University(SNU) and the Korean Research Institute for Standards and Science(KRISS). Although measurements of major gaseous pollutants had been made routinely by many scientific institutes and organizations in Korea, most scientists involved in those studieswere obliged to do their experiments on the basis of their own procedural steps spaning from the preparation of gaseous standards to the methodological selections for the calibration. Hence, this campaign offered a unique opportunity to examine many important aspects on the measurements of these important gaseous pollutants. In the course of our study, we investigated the compatibility of data sets obtained by the two institutes in concert with reference data sets collected concurrently from a government-managed monitoring station. On the basis of our study, we conclude that different data sets made by different participants during this campaign agree well within the reasonable range of uncertainties.low, which indicated that during this period the potential acidity of precipitation was high but the neutralizing capacity was low. For Spring, pAi was very low but pH was slightly high. This was likely due to the large amount of $CaCO_3$ in the soil particles transported over a long range from the Chinese continent that were incorporated into the precipitation, and then neutralized the acidifying species with its high concentraton.

• 대한환경공학회지
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• 제22권11호
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• pp.1969-1976
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• 2000

폐수의 복합독성과 다수의 미지 화합물의 영향을 평가하는 것은 많은 시간이 요구되고 분석상 어려움이 존재하는 경우가 많다. 그러므로 폐수중 독성을 나타내는 원인물질의 탐색과 처리효과를 평가하기 위한 방법을 확립하는 것이 절실히 요구된다. 본 연구에서는 질산화 저해제를 이용하여 혼합미생물중 질산화 미생물과 종속영양미생물을 구분하여 암모니아 저해도 실험을 수행하였으며, 이때 저해도는 dehydrogenase activity(DHA)를 이용한 미생물활성도의 차이로서 평가하였다. DHA에 의한 암모니아 저해 연구는 총 암모니아의 영향, 유리 암모니아의 영향, 질산화 미생물과 종속영양미생물의 암모니아 저해도에 대해 각각 평가되었다. 암모니아 독성은 총 암모니아 농도와 pH가 증가할수록 크게 나타나 유리 암모니아의 역할이 중요하게 작용함이 밝혀졌으나 미생물의 DHA는 총 암모니아와 유리 암모니아가 함께 고려되어야 정확히 평가될 수 있었다. 3.000mg/L 이상의 고농도의 암모니아에서는 질산화 미생물이 종속영양미생물 보다 심한 저해를 받는 것으로 나타났다.

• 한국환경교육학회지:환경교육
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• 제18권3호
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• pp.75-90
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• 2005

The purpose of this study was to analyze middle school students' consumption lifestyle and develop a program for measuring Ecological Footprint (EF) for them. For this study, 200 male and female middle school students in large cities, medium & small cities were selected to analyze their consumption lifestyle. It was also that the existing programs for measuring EF were studied and basic rules of setting up new EF indicators were established based on the results of survey and literature study. 15 indexes was selected by dividing the life areas into food, housing, traffic, goods and services areas and than the delpi computer programming tools was used to develop program for measuring EF in this study. The program for measuring EF can be used as educational materials for consumers' environment education in the areas of social environment education and school environment education. The followings are suggestions coming out of this study. First, it is required to revise and complement program for measuring EF analyzing the problems that occur when applying it to middle school students actually. Second, some data that used during normalization of EF ate originally from the USA. So it is necessary to change the data to meet the Korean situation. Third, it is necessary to have design work that can invite interests of students with consumers' environmental education materials through cooperation between environmental education experts and computer programmers. Fourth, it is necessary to have practical research with consumers' environmental education adding educational contents into EF measurement program. Fifth, it is necessary to develop a method for distribution an expansion of the program for measuring EF to make it usable in different types of environmental education materials.

• 인간식물환경학회지
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• 제21권6호
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• pp.461-471
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• 2018

The role of urban agriculture should not be limited as a small-scale crop cultivation activity as it was, but it has to be considered as an entire process of a agriculture activity for the restoration of the city community. This study is based on the assumption that there has been a significant change in urban lifestyle and urban farming preference, considering the overall improvement in standard of living after implementation of five day work week system. It was conducted for urban citizens who were interested in actual urban agriculture for ages 19 and over who visited the Korea Urban Agriculture Exhibition in 2018. Only 115 valid samples were used for the empirical analysis. To analyze the demographic characteristics and effects of urban agriculture, frequency analysis and descriptive statistics were conducted. In order to analyze the reliability and validity of the measurement variables of the effect, the variables that deteriorate the validity were removed and 15 variables of the urban agricultural effect were selected. According to the result of factor analysis, three factors were extracted as follows: socially sustainable effect, negative effect and economically sustainable effect. In order to examine the effects of urban agriculture depending on income level, the one-way ANOVA, which is a statistical technique for verifying differences in the sample means, was performed. The psychological stability of people, the recovery of humanity through communion with nature, and the vitalization of agriculture linked with local agriculture had significant correlations with income level. The negative effect showed no significant correlation with income level. The improvement of the local environment was found to have an impact in relation with income level. We expect that there will be more studies on policies for the new types and models of urban agriculture in order to make it easier for urban citizens to approach it.