• Korean Journal of Construction Engineering and Management
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• v.19 no.6
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• pp.46-54
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• 2018

In the 21st century, the Earth has continued its efforts to reduce carbon emissions to overcome the crisis caused by climate change. The construction industry, which is a representative industry that produces large amounts of the environmental load during construction, should actively reduce the amount of the environmental load. From the planning stage of the construction facility, it is necessary to consider the environmental load such as route selection and structure type selection to reduce the environmental load. However, the environmental load can be estimated based on the input resource amount. However, in the planning stage, it is difficult to accurately calculate the environmental load due to lack of information on the construction amount. The purpose of this study is to select the environmental load factors for IPC girder bridges to be used in the environmental load estimation model in the planning stage. Specific information related to the environmental load was selected from a list of information available in the planning stage, reflecting the Life Cycle Assessment(LCA), correlation, principal components analysis and expert opinion. The list of selected planning stage information is 10 such as span length and bridge extension, and it is expected to be used as a basic data for the future development of environmental load estimation model.

• Resources Recycling
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• v.31 no.1
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• pp.56-64
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• 2022

Construction waste is generated at a rate of approximately 221,102 tons/day in Korea. In particular, mixed construction waste generates approximately 24,582 tons/day. The other components were recycled by 98.9%. The amount of greenhouse gas emissions from the waste was 17.1 million tons of CO2 equaling 2.3% of the total greenhouse gas emissions. To reduce greenhouse gas emissions, reducing the environmental impact is becoming increasingly important. However, appropriate treatment must first be established, as mixed construction waste is also increasing. Thus, an effective plan is urgently needed because it is frequently segregated and sorted by the landfill and incinerated. In addition, there is an urgent need to prepare various effective recycling methods rather than a simple treatment. Therefore, this study analyzed the environmental impact of the treatment of mixed construction waste by calculating greenhouse gas emissions. As a result, the highest greenhouse gas generation occurred during the incineration stage. Moreover, the optimal method to reduce greenhouse gas emissions is recycling and energy recovery from waste. In addition, the amount of greenhouse gas generated during energy recovery from the waste stage was the second highest. However, greenhouse gas emissions can be reduced by using waste as energy to reduce fossil fuel consumption. In addition, for the transportation stage, the optimal reduction plan is to minimize the amount of greenhouse gas emissions by setting the optimal distance and applying biofuel and electric vehicle operations.

• Journal of dental hygiene science
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• v.12 no.3
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• pp.197-207
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• 2012

The purpose of this study was to examine the impact of the oral health status and health care of elderly people on their self-rated health(SRH). The subjects on this study were 479 senior citizens who were at the age of 65 and up and resided in the city of Busan. They got a dental checkup, and a survey was conducted by having an one-on-one interview. After the collected data were analyzed, the following findings were given: The senior citizens were diagnosed with a mean of 1.43 systemic diseases, and hypertension(51.8%) was the most prevalent disease among them, followed by diabetes(25.1%), arthritis(41.8%), oral diseases(75.6%), stroke(9.0%) and heart diseases(15.9%). Their self-rated health was better when they were male, when they were aged between 65 and 69, when there was someone with whom they lived, when they were better educated and when they owned their own houses. But their self-rated health was poorer when they felt more oral symptoms, when they had more missing teeth and when they needed both of maxillary and mandibular dentures. Their self-rated health was more positively affected when they were better educated($\beta$=0.894), when they owned their own houses($\beta$=4.220), when they got a dental checkup on a regular basis($\beta$=2.997) and when the rate of their functional tooth was larger($\beta$=0.081). And that was more negatively influenced when they had a denture($\beta$=-1.110), when they had more oral symptoms($\beta$=-1.590) and when they had more systemic diseases($\beta$=3.363). There is a close relationship between the oral health and self-rated health of elderly people. Therefore how to promote their oral health should carefully be considered.

• Clean Technology
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• v.18 no.1
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• pp.69-75
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• 2012

In this study, we executed an environmental impact assessment about recycling of ITO (Indium Tin Oxide), used for touch panel. ITO is mainly used to make transparent conductive coatings for touch and flat screen LCD (Liquid Crystal Display), ELD (Emitting Light Device), PDP (Plasma Display Panel). This demand is increasing little by little. but form current status, ITO is discarded than recycling. It is important to recycling ITO for national strategies about resource conservation, and reduce environmental burden. Also Landfill or incineration of ITO cloud be harmful to the human health in the long-term. Material Life Cycle Assessment method (MLCA) was conducted for comparison landfill and recycling of ITO. MLCA would provide more information for environmental issues and potential environmental impacts of ITO. The study includes two scenarios, the basic scenario is recycling of ITO (10, 20, 30%) and the other scenario is landfill of ITO. In addition, amount of carbon dioxide and energy were calculated.

• Journal of the Korea Organic Resources Recycling Association
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• v.14 no.2
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• pp.101-111
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• 2006

In the present work, life cycle assessments (LCA) of various waste-plastic recycling methods (material recycling, refused derived fuel (RDF), recycling on furnace, and pyrolytic oil production) were carried out to investigate their impacts on the environment. Six types of impacts were considered. While the impact on global warming was found to be significant, the impact on others were negligible. The impact values on the global warming caused by the material recycling, RDF, and the recycling on furnace were negative, which implied that their impacts could be noticeably reduced when waste-plastic are used as an alternative to newly drawn plastics. The pyrolytic oil production, however, showed positive value, which may be due to the carbon dioxide produced during electric power generation. The pyrolytic oil production had the largest impact on the ozone layer destruction, which was due to ozone depleting substances produced from the process itself. These results can be used as a useful data for the enhancement of waste-plastic recycling.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.1915-1925
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• 1998

The switching system software is large scale, real-time multi-task system which requires high reliability. The reliability assessment of large-scale software is very important for the success of software development project. For this raeson, the software quality measurement is much more important. In this paper, we have learned about the software reliability, metho of the analysis of failure data and estimation of software quality. To estimate the software reliability, using the failure data found during of the system test. We apply the two software reliability growth models, named Goel-Okumoto(G-O) and S-shaped model, to estimate the software reliability. Also, we compared with the results and we reviewed fully not only development cycle but validation and verification of the test data, for each software versions. This paper presents a software reliability model that suitale the software development project and the activeity of quality control for the switching system.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.237-241
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• 2010

Many policies have been implemented to mitigate the greenhouse gases in atmosphere overall of sectors. With considering the distinct characteristics of the food security, agricultural sector is no exception to this situation. To this regard, total amount of carbon which is emitted through all of the agricultural production process is calculated, and being based on this result, the demand for the introduction of agricultural production system with low carbon has been rising. Case studies on the application of life cycle assessment (LCA) technique to agricultural sector are found in many countries. For example, life cycle inventory (LCI) data bases of crop, farm infrastructure, fertilizer, farm machinery, and etc., have been constructed and provided by Ecoinvent (Swiss centre for life cycle inventories) of Swiss. In Japan, Top-down typed LCA methodology for agriculture is developed based on the inter-industry analysis, and is evaluated according to the productive method of crop. On the other hand, environmental impact assessment of agricultural system using LCA in Korea is just in the beginning stages. So it is required to assess environmental impact on agricultural fertilizer and pesticide, and to develop their flow modeling, and methodology of LCA of agricultural sector. Environmental impact assessment on agricultural materials, machinery, and infrastructure will also be carried out.

• Journal of Periodontal and Implant Science
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• v.35 no.1
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• pp.123-132
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• 2005

중등도 이상의 치주염 환자에서 치은 열구액내의 MMPs 및 TIMP-1 과 치주염과의 연관성을 규명하고, 치주 수술이 MMPs 및 TIMP-1의 정량에 미치는 영향을 연구하고자 하였다. 총 14명의 치주낭 깊이 6mm 이상의 중등도 이상의 치주 질환 이환자에서 치아를 선정하여, 치주낭 심도, 치은 지수(gingival index)를 측정하고, 치은의 조직학적 염증의 정도를 측정하기 위해, 해당 치아의 치주낭 연조직을 절취하여 H-E염색을 하고, 치은 절편에서 염증세포 침윤의 정도 및 분포를 비교하였다. Perio-paper를 이용하여 치은열구액을 얻고, pyrogen-free water에서 추출하였다. 채취한 치은 열구액에서 ELISA-kit를 이용하여 MMP-1, 8, 9, 13과 TIMP-1을 측정하여 수술 전과, 수술 후, 그리고 건강한 조직인 대조군을 비교하였으며, 통계처리는 Wilcoxon 검정을 사용하였다. 또한 MMPs 혹은 TIMP-1이 치주낭 심도나 치은지수등의 임상적 지표와 가지는 연관성을 Spearman's correlation coefficient를 이용하여 알아보았다. TIMP-1을 제외한 MMP-1, 8 ,9, 13 에서 수술 전보다 수술 후에 치은 열구액 내의 양이 현저하게 줄어든 것을 관찰할 수 있었으나, MMP-1(p=0.025), MMP-9(p=0.016) 와 MMP-13(p=0.009) 에서만 통계적으로 유의성있는 차이를 보였다. 한편 MMP-9 (p=0.011) 나 MMP-13(p=0.026) 은 건강한 대조군과 수술 전 사이에도 유의성있는 차이를 보였다. 연조직의 조직학적 관찰을 통하여 치은지수의 임상적 신뢰도를 평가한 결과 통계학적으로 유의한 결과를 얻을 수 있었으며, 치주 치료 전의 치주낭 심도와 치은지수와의 관계나, 수술 전과 수술 후의 치주낭 심도등의 변화도 통계적으로 유의성있는 결과를 보였다. 하지만 치주낭 심도나 치은지수등의 임상적 지표는 MMPs나 TIMP의 정량과는 별다른 연관성을 보이지 않았다. 이 실험의 결과로 보아 MMP-1, MMP-9나 MMP-13을 치주 수술 전과 수술 후의 치주염의 심도 변화를 반영할 수 있는 지표로 생각할 수 있으며, 특히 MMP-9와 MMP-13가 치주염과 가지는 연관성은 크다고 할 수 있겠다.

• Journal of the Korea Institute of Building Construction
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• v.22 no.2
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• pp.137-148
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• 2022

Recently, in the concrete industry, the development and commercialization of low-carbon products of ready-mixed concrete have emerged as part of the efforts to realize carbon neutrality. This study aims to investigate the current status of environmental product declaration(EPD) of ready-mixed concrete and to analyze the characteristics of carbon emissions by compressive strength, life cycle stage, and region. To this end, the related certification system requiring the calculation of carbon emissions in the concrete industry was analyzed. The target of analyzing the current status of carbon emissions was set as a product of ready-mixed concrete that acquired EPD certification based on the life cycle assessment method. In addition, the trend of carbon emissions according to each characteristic was reviewed by analyzing carbon emissions by the life cycle of ready-mixed concrete products, analyzing carbon emissions by standard, and analyzing carbon emissions by region. As a result, the carbon emissions in the pre-production stage were 99% compared to total carbon emissions., and as it increased from 18MPa to 40MPa, carbon emissions also increased. Even with the same specifications, the carbon emissions in the capital region were higher than in the southern region.

• Journal of the Korea Concrete Institute
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• v.26 no.3
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• pp.239-245
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• 2014

This study analyzed a comprehensive database including 6331 ready-mixed concrete plant mixtures to quantitatively assess the environmental impact of concrete under mixture proportions variable according to the domestic region and season. The environmental impact indicator includes global warming, photochemical oxidant creation, abiotic resource depletion, acidification, eutrophication and human toxicity, which are determined from categorization, characterization, normalization and weighting process based on Korea lifecycle inventories. The determined environmental impact indicator was also normalized by concrete compressive strength ($f_{ck}$), which is defined as impact index, to calculate the environmental impact per unit strength of 1 MPa. The most common compressive strength of concrete used in the country is estimated to be 24 MPa and 27 MPa. For $f_{ct}$ of 24 MPa, the lowest environmental impact indicator is observed in Ulsan, whereas the highest region is Gwangju and Daegu. This difference according to domestic region is primarily resulted from by the replacement of different supplementary cementitious materials. Furthermore, the impact index of concrete with $f_{ck}$ of 24 MPa is higher by approximately 5% at wintertime than at summertime and standard season. The impact index gradually decreases with the increase of $f_{ck}$ up to 35 MPa, beyond which it remains constant.