• Environmental and Resource Economics Review
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• v.16 no.3
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• pp.451-483
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• 2007

Recently, the problem of noise has received much attention in the urban environment. This paper attempts to measure the economic benefits of urban noise reduction in the metropolitan area. To this end, the dichotomous choice contingent valuation method is applied. In particular, recently proposed one and one-half bound model that reduces the potential for response bias in the double bound model while maintaining much of its efficiency. We surveyed a randomly selected sample of 800 households in the metropolitan area and asked respondents questions in person-to-person interviews about how they would willing to pay for the noise reduction. Respondents overall accepted the contingent market and were willing to contribute a significant amount (997 to 1,778 won), on average, per household per month. This willingness varies according to individual characteristics such as concerns about noise, dwelling area, and income. The aggregate value of the noise reduction in the sampled metropolitan area amounts to approximately 79.26 to 141.35 billion won per year.

• Journal of Environmental Policy
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• v.5 no.3
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• pp.79-103
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• 2006

This paper attempts to examine household's willingness to pay (WTP) for piped water quality improvement in Wonju, where the local government are planning to implement a piped water quality improvement program. We apply a contingent valuation (CV) method to obtain at least a preliminary evaluation of the WTP. The CV survey was rigorously designed to comply with the guidelines for best-practiced CV studies. We surveyed a randomly selected sample of 250 households in Wonju and asked respondents questions in person-to-person interviews about how much they would be willing to pay for the program. Respondents overall accepted the contingent market and were willing to contribute a significant amount (1,583 to 2,776 won), on average, per household per month. This willingness varies according to individual characteristics such as sex, education level, and income. The aggregate value of the program in Wonju amounts to approximately 1.99 billion won to 3.49 billion won per year. The household values can be the benefits that ensue from the program and compared with the costs of the program to determine whether the program is economically desirable.

• Journal of Korea Water Resources Association
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• v.46 no.10
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• pp.997-1004
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• 2013

There is imminent need to find a way to measure the recreational benefits of water so that appropriate actions can be taken to make a multi-purpose reservoir. Therefore, this study attempts to apply a choice experiment to quantifying the recreational benefits of a multi-purpose reservoir, using a specific case study of Sangkwan multi-purpose reservoir. We consider the trade-offs between price and attributes of recreational attributes for selecting a preferred alternative and derive the marginal willingness to pay (MWTP) estimate for each attribute. The results show that the MWTP for providing additional 10,000 ton of water is estimated to be 3 won per household per year. The MWTP for improving 1 level of water quality is computed to be 645.5 won per household per year. Moreover, the MWTP for providing recreation facilities is calculated to be 1,518.6 won per household per year. This study allows us to provide policy-makers with useful quantitative information that can reduce uncertainty in the decision-making process related to a multi-purpose reservoir construction projects.

• Composites Research
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• v.28 no.4
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• pp.239-243
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• 2015

Recent studies regarding the properties of carbon nanotubes (CNT) have made remarkable progress in CNT fibers research. However no CNT fibers showed the properties of CNTs because CNTs in fibers have weak interfacial bonding with low shear modulus in the pristine form. Thus, it is upmost interest to develop and employ post-production treatments to the CNT fibers that would potentially improve their properties. In this study, post-treatments resulted in improvement of strength of CNT fibers up to 40%.

• Journal of Environmental Policy
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• v.13 no.3
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• pp.21-42
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• 2014

Abandoned roads, abandoned expressways included, cause a lot of problems such as contamination and environmental damages to underground water, fragmentation of wildlife habitats yet they are not appropriately maintained or managed because of jurisdictional conflicts and, often more importantly, insufficient budget of governments. The restoration of abandoned roads is known to benefit society and its constituents by providing better environment and higher living standards but the monetary value of the benefit is hard to measure because of non-marketability of the good that the restoration brings about. In this case, the contingent valuation method(CVM) is most powerful in evaluating non-marketable value of goods and hence it is used widely. We also used the CVM to value the benefit of restoration of abandoned expressways to find out: about 40% of total households are willing to contribute positive amount for restoration; better awareness of environmental issues leads to higher willingness-to-pay.

• Journal of Korea Water Resources Association
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• v.45 no.1
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• pp.29-37
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• 2012

This paper attempts to measure the economic benefits of tap water quality improvement using a specific case study of Ulsan, one of the large cities in Korea. To this end, we apply the contingent valuation (CV) method by employing a one-and-one-half bounded spike dichotomous choice question format. We surveyed a randomly selected sample of 400 households in Ulsan and asked respondents questions in person-toperson interviews about how they would willing to pay for the program. Respondents overall accepted the contingent market and were willing to contribute a significant amount (1,611 won), on average, per household per month. This willingness varies according to individual characteristics such as education level and income. The aggregate value of the program in Ulsan amounts to approximately 8 billion won per year.

• Journal of Korean Society of Transportation
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• v.23 no.1
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• pp.55-66
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• 2005

Association of South East Asian Nations(ASEAN) has recently decided to develop ASEAN Highway Network to connect member countries by road in an attempt to achieve a goal of closer economic integration in the region. This entailed the necessity to newly construct or upgrade some 5,481 km of road sections to make ASEAN Highway Network functional. This study offers haw we can prioritize development of these road sections using the Analytic Hierarchy Process. Particularly, it shows how individual road sections can be prioritized considering the importance of corridor or road group where the individual road section lies. It also develops how values of different evaluation criteria can be compared in the same scale. This new approach can be useful in prioritizing highway development in such cases where candidate road sections are widely scattered around the region, so detailed benefit and cost analysis is practically too demanding to carry out.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.24-24
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• 2010

Chalcopyrite $Cu(In,Ga)Se_2$ (CIGS) 화합물 반도체는 고효율 박막태양전지의 광 흡수층으로 사용되는 물질 중 가장 우수한 효율 (19.9%, NREL 2008)을 보유하고 있다. CIGS는 직접천이형 에너지밴드갭 (direct bandgap)을 가지고 있고, 광흡수계수가 $1{\times}10^5\;cm^{-1}$로서 반도체 중 서 가장 흡수율이 높은 재료에 속하여 두께 $1{\sim}2\;{\mu}m$의 박막으로도 고효율의 태양전지 제조가 가능하고, 또한 장기적으로 전기광학적 안정성이 매우 우수한 특성을 지니고 있다. 현재 고효율 CIGS 셀생성을 위해 널리 사용되고 있는 CIGS 흡수층 성장공정은 "co-evaporation(동시증발법)"과 2-step 공정이라 불리는 "sputter-selenization(스퍼터-셀렌화)" 방법이다. 동시증발법은 개별원소 Cu, In, Ga, Se 들을 고진공 분위기에서 고온 ($550{\sim}600^{\circ}C$)기판위에 증착하는 방법으로 소면적에서 가장 좋은 효율(~20%)을 보이는 공정이다. 하지만, 고온, 고진공 공정조건과 대면적 증착시 온도 및 조성 불균일 등의 문제점 등으로 상용화에 어려움이 있다. 스퍼터-셀렌화 공정은 1단계에서 스퍼터링 방식으로 CuGaIn 전구체를 증착하고, 2단계에서 고온($550{\sim}600^{\circ}C$)하에 $H_2Se$ 혹은 Se vapor와 반응시켜 CIGS를 생성한다. 일본의 Showa Shell와 Honda Soltec 등에 의해 이미 상업화 되었듯이, 저비용 대면적으로 상업화 가능성이 높은 공정으로 평가되고 있다. 하지만, 2단계에서 사용되는 $H_2Se$ 및 Se vapor의 유독성, 기상 Se과 금속전구체 간의 느린 셀렌화 반응속도, 셀렌화반응 후 생성된 CIGS 박막 두께방향으로의 Ga 불균일분포, 생성된 CIGS/Mo 계면 접착력 저하등의 문제점들이 해결되어야만 상업화에 성공할 수 있을 것이다. 본 Tutorial에서는 CIGS 물질의 열역학 상평형과 반응메카니즘에 대해 설명하고, 다양한 생성 공정들을 소개할 것이다.

• Journal of Korea Water Resources Association
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• v.54 no.10
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• pp.759-768
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• 2021

This work introduces a new approach that classifies individual household water usage by examining the characteristics of smart meter end-user demand data. Here, one of the most well-known unsupervised machine learning, K-means algorithm, is applied to classify water consumptions by each household. The intensity and duration of end-user demands are used as main features to determine the households with similar water consumption pattern. The results showed that 21 households are classified into 13 clusters with each cluster having one, two, three, or five houses. The reasoning why multiple households are classified into the same cluster is described in this paper with respect to the collected data and end-user water consumption behavior.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.1-9
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• 2019

The purpose of this study is to examine the system of the Jeokbyeok-ga's version using the Computer analysis technique of bibliographies and to examine the achievements of the Jeokbyeok-ga's version studies. First, in order to provide basic data for analysis, a raw corpus was constructed for 46 species of Jeokbyeok-ga. Through this, the common narrative units of the Jeokbyeok-ga were identified as 5 layers, and thus 146 individual paragraphs could be extracted. Based on the encoded corpus, we tried to measure the similarity and the distance between the two. Next, we applied the Multidimensional scaling method, Hierarchical cluster analysis and Cladistic analysis method of the system to confirm the distribution of versions group and it was possible to visually grasp the distance between versions and the system of the work. As a result of analyzing Computer analysis technique of bibliographies, it was found that version's group of the Jeokbyeok-ga was divided into a Wanpan(完板) series and Changbon(唱本) series. Also, it was possible to examine the influence relationship between the Pansori's traditions and transmission.