• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.16 no.4
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• pp.413-427
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• 2006

It is necessary to study and develop guidelines for providing comfort and health indoor air quality for office workers since air-tight envelope system of current office building may cause poor indoor air quality. The purpose of this study is to propose guideline for volatile organic compounds in office base on the field study, human health risk assessment and cost-benefit analysis. The field study was conducted to survey the concentrations of volatile organic compounds in indoor air of 69 offices from June to September, 2005 in Seoul and Gyeonggi-do. The rate of excess to guideline of volatile organic compounds in indoor air of new apartment on the Ministry of Environment in Korea(MOE) was surveyed 37.6% for benzene, 6.8% for toluene, and 1.5% for ethylbenzene. As the result of human health risk assessment, mean cancer risk did not exceed 10-6 which is guideline of US.EPA. Also, total hazard index did not exceed 1 which is guideline of US.EPA. Through the cost-benefit analysis of angle on the social-economics to verify the necessary to establish the standards of volatile organic compounds for improvement and development of indoor air quality in office, the present value of benefit was higher than the present value of cost. With the above considerations in mind, it is suggested that the field study for indoor air quality in offices should be expanded and human health risk assessment and cost-benefit analysis be performed th offer scientific data for decision-making of policy for improvement and management of indoor air quality in office.

• Environmental and Resource Economics Review
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• v.27 no.2
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• pp.339-362
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• 2018

In this paper, we simulate the contribution of an increasing renewable energy to demands for fossil fuels and power supply price by estimating a cost function for the Korean electric power generation sector. Since the renewable energy is a composite input, it is not feasible to compute the price index for renewable energy due to data limit. We estimate a restricted cost function, which is derived by minimizing the costs of fossil fuels conditional on the quantity of renewable energy set to its optimal level, jointly with supply relation. In particular, derivation of the shadow price of renewable energy would make it possible to analyze potential costs incurred by power plants.

• Journal of Environmental Impact Assessment
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• v.7 no.2
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• pp.89-102
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• 1998

The purpose of this study is to seek AEI(Air Environmental Indices), PSI(Pollutant Standard Index) and the urban air quality control goal(the best available alternative energy program) by assessing the best ratio of energy types used in urban enterprises, based on harmful health effect and air quality standard and costs. This study is focused on an urban area(Puchun), where area sourcees are associated with heavy traffic, large population, and its industrial sources with large emissions. In the first step, air modeling, estimation of AEI and PSI, and benefit-cost analysis were carried out. In the second step, we assessed that 660 scenarios about the ratio of B-C oil, light oil and LNG used in urban enterprises with regard to air quality and cost. In the third step, the best available alternative energy program was selected for the ratio of energy species(B-C oil, light oil and LNG) by using the lexicographic method. From the emission analysis, main source of $NO_2$ is identified as industries and air quality is evaluated according to the ratio of B-C oil, light oil and LNG used in urban enterprise. The modeling data of TSP, $SO_2$, $NO_2$, CO, $O_3$, by ISC3 and PBM are respectively $118{\mu}g/m^3$, 0.027ppm, 0.025ppm, 2.0ppm, 0.55ppm in indurstrial area. That data are close to Environmental Air Quality Standard. By means of sensitivity analysis, we obtained the difference in concentration between the areas(Nae-dong, Joong-dong) according to the ratio of B-C oil, light oil and LNG used in the industries. From the result of alternatives assessment the lowest AEI value and cost, the ratio of B-C oil, light oil and LNG are 2.5%, 20%, 77.5%, respectively.

• Land and Housing Review
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• v.5 no.4
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• pp.297-303
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• 2014

Recently, block and permeable pavements have been placed in apartment complex. However. it is hard to decide the cycle of maintenance and repair due to lack of performance evaluation criteria for these pavements. This study carried out life cycle cost analysis(LCCA) to present resonable alternatives of the pavements by considering initial construction cost, maintenance and repair cost along with the cycle of repair. According to results of LCCA, the interlocking concrete block pavement is the best alternative when the repair cycle of 20years is assumed, while asphalt concrete pavement is the best alterative when the repair cycle of 10years is assumed. Therefore, the repair cycle is most important factor to select alternative. Also, it is necessary to develop resonable performance evaluation index to quantify the cycle of maintenance and repair in the future.

• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.647-658
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• 2000

The purpose of this study is to estimate the forward impact of water supply bottleneck using a supply-side input-output model. The failure cost analysed in this study can be used to estimate the values of the water supply reliability and can provide the bases of policy decision for the effective reallocation when water supply constraint will occur. So the position of water supply in the national economy is identified, and direct and indirect impacts are estimated by means of the interindustry analysis. Also the failure cost index is suggested to determine the prior order of water supply important in drought. By the way, the occurrence of drought having regional properties, the failure cost of the regional level using a national input-output table may be overestimated or underestimated. For the preceding reason, the failure cost estimated by a national input-output table is compared with and analysed to a regional input-output table for Kyung- Nam.g- Nam.

• Journal of Gastric Cancer
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• v.12 no.2
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• pp.126-131
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• 2012

Purpose: We developed a standardized critical pathway for gastric cancer surgery and then determined the increase of application, which resulted in an improvement in terms of measurable indices, such as hospital stay and cost. Materials and Methods: A critical pathway was revised and used widely from the 2nd quarter of 2009. We collected clinical data, such as length of stay and complication rate, as clinical indices of quality prospectively. The total cost paid at the patient's discharge, as well as the daily hospital income, were calculated and compared by each quarter from January 2008 to December 2009. Results: The application rate of critical pathway was 11.8% and 87.8% in 2008 and 2009, respectively. There were no perioperative deaths. There was no difference in the complication rates between 2008 and 2009 (P=0.45). However, the mean length of stay was significantly different between the 2 years (P<0.05). Although the total cost was not different, the daily hospital income was significantly higher in the latter year (P<0.05). Conclusions: An increase in the application of critical pathway for gastrectomy resulted in significant decreases in length of stay and increases in the daily hospital income without a compromise on the clinical indices.

• International Journal of Highway Engineering
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• v.18 no.4
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• pp.19-28
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• 2016

PURPOSES : Long-life asphalt pavements are used widely in developed countries. In order to be able to devise an effective maintenance strategy for such pavements, in this study, we evaluated the performance of the long-life asphalt pavements constructed along the national highways in South Korea. Further, an economic evaluation of the long-life asphalt pavements was performed based on a life-cycle cost analysis. We aimed to devise a model for evaluating the performance of long-life asphalt pavements using the national highway pavement management system (PMS) database as well as for analyzing the economic feasibility of such pavements, in order to promote their use in South Korea. METHODS : The maintenance history and pavement performance data were obtained from the national highway PMS database. The pavement performances for a total of 292 sections of 10 lanes (5 northbound lanes and 5 eastbound lanes) of national highways were used in this study. Models to predict the performances of hot mix asphalt (HMA) and long-life asphalt pavements under two distinct traffic conditions were developed using a simple regression method. Further, the economic feasibility of long-life asphalt pavements was evaluated using the Korea Pavement Management System (KoPMS). RESULTS : We developed service-life prediction models based on the traffic volume and the equivalent of single-axle load and found that long-life asphalt pavements have service lives 50% longer than those of HMA pavements. Further, the results of the economic analysis showed that long-life asphalt pavements are superior in terms of various economic indexes, including user cost, delay cost, total cost, and user benefits, even though their maintenance cost is higher than that of HMA pavements. A comparison of the economic feasibilities of the various groups showed that group A is superior to HMA pavements in all aspects except in terms of the maintenance criterion (crack 20% or higher) as per the NPV index. However, the long-life asphalt pavements in group B were superior in terms of the maintenance criterion (crack 25% or higher) regardless of the economic feasibility. CONCLUSIONS : The service life of long-life asphalt pavements was found to be approximately 50% longer than that of HMA pavements, regardless of the traffic volume characteristics. The economic feasibility of long-life asphalt pavements was evaluated based on the KoPMS. The results of the economic analysis were the following: long-life asphalt pavements are exceptional in terms of almost all factors, such as user cost, delay cost, total cost, and user benefit; however, the exception is the maintenance cost. Further, the economic feasibility of the long-life asphalt pavements in group B was found to be better than that of the HMA pavements (crack 25% or higher).

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.11a
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• pp.183-186
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• 2007

We introduction some properties for fuzzy power function of performance of a test. First we define fuzzy type I error and type II error for the probability of the two types of error. And we show that an fuzzy error probability of one kind can only be reduced at cost of increasing the other fuzzy error probability.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.98-100
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• 2004

We report a novel manner for preparing single layer anti-reflective coatings with excellent optical properties (<1% reflection) over a broad wavelength regime. The technology is based upon the self-assembly and UV curing of reactive nano-particles, leading to nano-structured coatings with a gradient in refractive index. The single processing step leading to such coatings is fast, robust and cost effective. Furthermore in this paper we will address the mechanical durability of such nano-structured coatings.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.04a
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• pp.570-573
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• 1996

The evaluation test for the operation of rotary type surface mounters which consist of the reel axis, the index table and the X-Y table, has been performed by comparing the new method with the old one in only fields. Because the problem seeking for the optimal operation of rotary type surface mounters, is NP complete, it is almost impossible to get the optimal solutions of large problems. This paper deals with a dynamic network modeling, which can reduce the effort, the cost, and the time used for the performance test of rotary type surface mounters.