• Proceedings of the KSR Conference
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• 2011.10a
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• pp.931-938
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• 2011

Nondestructive inspection(NDI) is a testing procedure used to easily inspect an object for internal defects, abnormalities, shape, and structure, etc. without destroying it. Typical candidates for NDI include buildings, railways, aircraft, bridges, underground pipelines and various types of factory equipment. Recent advances in nondestructive evaluation(NDE) technologies have led to improved methods for quality control and in-service inspection, and the development of new options for material diagnostics. Under frame side sill in rolling stocks is designed for preventing corrosion in order to meet mechanical requirements. However during long operation time, there are corrosion in the under frame side sill caused by environmental effect, vibration and etc. This paper introduces the methods of a survey and assessment on NDI applications in Electric Multiple Units(EMU). The main objective of this paper was to obtain information on various applications and evaluation of NDI technology in EMU.

• Journal of the Korean Home Economics Association
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• v.33 no.4
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• pp.157-172
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• 1995

The purpose of this study was to develop a measurement model for evaluation of residential environment in low-income families. Residential environment means the housing unit itself and neighborhoods and community characteristics. Based on the previous research on housing environment, six factors (comfortable environment in indoor and outdoor, facilities environment in complex and community, sociopsychological environment, management and economic environment) were selected to evaluate residential environment and to provided a foundation for exploring the multidimensional factors of this research. As s confirmatory study, an Analysis of Linear Structural Relationships(LISREL) was utilized to develop the model. Despite of some measurement errors, the goodness of fit of an overall model was acceptable. Facilities environment in complex and sociopsychological environment were the most important factors in residential environmental evaluation of the low income families. the findings showed that housing policies and programs to improve the quality of homes in low-income families seemed to be beneficial to improve residential satisfaction of the residents.

• Journal of Environmental Health Sciences
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• v.40 no.5
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• pp.376-384
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• 2014

Objective: The purpose of this study is to compare the health status of residents who were exposed to sources of extremely low frequency electromagnetic fields (ELF-EMFs) in the living environment and those who were not exposed to such a source of ELF-EMFs through a survey designed to appraise the residents' health levels. Method: Aimed at 251 residents exposed to a source of ELF-EMFs and 278 residents not exposed to a source, the survey was conducted to investigate the health status of the residents on the basis of questionnaire SF-36. Result: The health status scores of residents exposed to ELF-EMFs turned out to be lower than those of their counterparts. In terms of self-reported symptoms related to health and sleep quality, residents exposed to ELF-EMFs were found to have a higher complaint rate of self-reported symptoms such as dizziness, depression, and fatigue. Regarding sleep disorders, residents exposed to ELF-EMFs appeared to have a slightly higher complaint rate of sleep disorders compared to non-exposed residents. Conclusion: If a region is to be exposed to a source of ELF-EMFs, a more proactive policy for reducing such exposure is advised. In addition, it is necessary to better understand problems of residents by emplacing an ELF-EMFs risk information delivery system and building an efficient communication system for voluntary participation during the construction phase.

• Journal of Environmental Science International
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• v.18 no.9
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• pp.971-981
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• 2009

An objective of this study is as follows: 1) performing sensitivity analysis and parameter estimation of RMA2 and RMA4 models for the West-Nakdong River, 2) drawing up alternatives of gates-operation for water-quality enhancement, and 3) quantitative evaluation of methodology of 'flow-restoration by gates-operation' among 'Comprehensive Plan Improving Water-Quality in the West-Nakdong River(WNR)' with the target water-quality(BOD at Nakbon-N point: below 4.3 mg/L). The parameters for the RMA2 (depth-averaged two-dimensional flow model) and RMA4 (depth-averaged two-dimensional water-quality model) were determined by sensitivity analysis. Result of parameter estimation for RMA2 and RMA4 models is $1,000\;Pa{\cdot}s$ of the eddy viscosity, 20 of the Peclet number, 0.025 of the Manning coefficient, and $1.0\;m^2/s$ of the diffusion coefficient. We have evaluated the effects of water-quality enhancement of the selected alternatives by numerical simulation technique with the models under the steady-state flow condition and the time-variant transport condition. Because of no-resuspension from river bottom and considering BOD as conservative matter, these simulation results slightly differ from real phenomena. In the case of $50\;m^3/s$ of Daejeo-gate inflow, two-dimensional flow pn results result represents that small velocity occurs in the Pyungkang Stream and no flow in the Maekdo River. In the WNR, there occurs the most rapid flow near timhae-bridge. In the WNR, changes of water-quality for the four selected simulation cases(6, 10, 30, $50\;m^3/s$ of the Daejeo-gate inflow) were predicted. Since the Daejeo-Gate and the Noksan-Gate can be opened up to 7 days, it would be found that sustainable inflow of $30\;m^3/s$ at the Daejeo-gate makes BOD in the WNR to be under the target of water-quality.

• Journal of Wetlands Research
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• v.24 no.4
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• pp.301-311
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• 2022

The purpose of this study is to analyze the seasonal characteristics of water quality using long-term water quality monitoring data. Seasonal characteristics of water quality were analyzed using monitoring data from 34 tributaries where long-term monitoring was performed in the Nakdong River system, and average data analysis of water quality, coefficient of variation analysis, and trend analysis were performed for seasonal analysis. For seasonal analysis, average data analysis of water quality, coefficient of variation analysis, and trend analysis were performed. As a result of the evaluation of the coefficient of variation, tributaries were larger than main streams, and BOD, T-P, and TOC were larger in autumn and T-N were larger in spring. Trend analysis was analyzed using Mann-Kendall and Sen's Slope. BOD, T-N, and T-P tended to decrease, but TOC had a lot to increase. Through this study, it was possible to evaluate the availability of long-term water quality monitoring data and analyze seasonal characteristics, and to analyze the stabilization period of water quality and changes in pollutant sources for watershed management.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.621-624
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• 2008

Repair materials which applied to the concrete structures may have different quality characteristics depending on the environmental factors. Evaluation on durability of domestic repair materials have not yet secured enough quality performance on durability, mainly due to the lack of test methods resulted from various environmental factors. In this study, we carried out the tests on freezing and thawing resistance of domestic repair materials with different environmental factors applied under BS EN 13687, and analyzed the results by comparing with Korea's national test standards(KS F 4716). The results indicate that after the repetition of dry and wet conditions and the test on freezing and thawing with salt immersion resistance bond strength might show great difference depending on the type of repair materials and the size of sample. For securing better quality performance of repair materials, it is required to establish various standards on the test methods of freezing and thawing resistance with different environmental factors applied.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.133-141
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• 2017

Traffic volume increases according to highway expansion and industrial development which causes repetitive defect and durability degradation on pavement. The research of quality assurance system used abroad has introduced Korea. Korea Expressway Corporation (KEC) has developed a Quality Performance Index (QPI) that quantitatively assesses the level of quality of the final product, and practical applications. Assessment factor on concrete pavement consisted of pavement thickness, compressive strength, IRI and spacing factor. Assessment factor on concrete pavement is determined by empirical evaluation factor from abroad. In this study, analysis of evaluation factors of concrete pavement by using pavement life prediction simulation and measured data were evaluated with consideration of feasibility of the assessment factor. Pavement life, performance and durability are affected by pavement thickness, compressive strength, IRI and spacing factor in assessment factor on concrete pavement, QPI.

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.5
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• pp.501-512
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• 2016

The study evaluated methods to measure condensable fine particles in flue gases and measured particulate matter by fuel and material to get precise concentrations and quantities. As a result of the method evaluation, it is required to improve test methods for measuring Condensable Particulate Matter (CPM) emitted after the conventional Filterable Particulate Matter (FPM) measurement process. Relative Standard Deviation (RSD) based on the evaluated analysis process showed that RSD percentages of FPM and CPM were around 27.0~139.5%. As errors in the process of CPM measurement and analysis can be caused while separating and dehydrating organic and inorganic materials from condensed liquid samples, transporting samples, and titrating ammonium hydroxide in the sample, it is required to comply with the exact test procedures. As for characteristics of FPM and CPM concentrations, CPM had about 1.6~63 times higher concentrations than FPM, and CPM caused huge increase in PM mass concentrations. Also, emission concentrations and quantities varied according to the characteristics of each fuel, the size of emitting facilities, operational conditions of emitters, etc. PM in the flue gases mostly consisted of CPM (61~99%), and the result of organic/inorganic component analysis revealed that organic dusts accounted for 30~88%. High-efficiency prevention facilities also had high concentrations of CPM due to large amounts of $NO_x$, and the more fuels, the more inorganic dusts. As a result of comparison between emission coefficients by fuel and the EPA AP-42, FPM had lower result values compared to that in the US materials, and CPM had higher values than FPM. For the emission coefficients of the total PM (FPM+CPM) by industry, that of thermal power stations (bituminous coal) was 71.64 g/ton, and cement manufacturing facility (blended fuels) 18.90 g/ton. In order to estimate emission quantities and coefficients proper to the circumstances of air pollutant-emitting facilities in Korea, measurement data need to be calculated in stages by facility condition according to the CPM measurement method in the study. About 80% of PM in flue gases are CPM, and a half of which are organic dusts that are mostly unknown yet. For effective management and control of PM in flue gases, it is necessary to identify the current conditions through quantitative and qualitative analysis of harmful organic substances, and have more interest in and conduct studies on unknown materials' measurements and behaviors.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.3
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• pp.192-199
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• 2013

The Tandong-cheon stream is a 7.4 km long small urban stream that passes through Daeduk Science Town in Daejeon Korea. Despite the stream has great potential as an educational and recreational site due to its central location in the science town and science museums nearby, environmental aspect especially for water quality has not been evaluated properly. Through field survey, major pollution sources of the stream were identified and effect of water quality improvement alternatives were evaluated using a QUAL2K water quality model for the stream. The study indicated that controlling major pollution sources of the stream alone may not be sufficient for reaching the water quality target. Therefore, additional pollution control methods are necessary. We applied the developed model to evaluate the effects of a constructed wetland on the terrace land, and analyzed whether the water quality target can be met at the outlet of the stream. It is expected that this study would provide a good reference for environmentally sound management of small urban streams in Korea.

• Journal of Korean Society of Rural Planning
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• v.3 no.1
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• pp.75-85
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• 1997

Kim, Bong-won * · Kim, Yoo-ill *1 Dept. of Landscape Architecture, Sungkyunkwan Univ. ABSTRACT The purpose of this study was to evaluate the Quality of Life with a sample set collected from 37F residents in Seoul Metropolitan's countryside. Collected data were analyzed by means of regression analysis. Research results indicated that the predictors of Quality of Life had a relationship with'job satisfaction','self satisfaction','residential satisfaction','income satisfaction'and other variables(Ra= .48). The residents who strongly satisfied with those variables were likely to satisfy with their life. Also, the existence of toyon office and the educational level emerged as a significant factors for the life satisfaction. This means that the residents located at toyon office or educated higher level satisfied more on their life. Thus the personal characteristics and environmental attributes played a basic role on the life satisfaction. Implications for future research are discussed, and methodological and analytical weaknesses of this study are identified.