• Resources Recycling
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• v.17 no.2
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• pp.55-62
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• 2008

Amount of waste is always generated in industrialization process and it is gradually increasing. Domestic and industrial waste in 2003 increased by 9.5 percent than that of the last year(2002), whereas the amount of construction waste increased largely by 21 percent. Recently construction waste of total waste accounts for nearly 50 percent, waste concrete and Ascon from the construction waste takes up to 73 percent. Furthermore, amount of natural materials are gradually decreasing, that is, they are not sufficient any more. Owing to these reasons, the importance of recycling construction waste has been emphasized. The use of recycling aggregate makes the disposal of construction waste easier as well as protects environment from gathering raw aggregate. Also, it has the alternative effect economizing the insufficient new natural aggregate. This study employs the cost-benefit model to analyze the economic effect of construction waste recycling of Ascon which takes relatively high part of the total waste. The cost-comparison between raw aggregate and recycling aggregate were analyzed. With the model, the economic effect of Ascon recycling in 2003 and 2004 in capital area of Korea were analysed. Cost comparison between raw aggregate and recycling aggregate were also carried out. The result showed that the economic effect of Ascon recycling increased to 0.0808 for 2004 as compared 0.0694 for 2003. We could not conclude using above data, but this result shows that the economic benefit of Ascon recycling of construction waste has increased.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1489-1493
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• 2008

신규 수자원개발을 위해서는 사회적으로 공감대를 형성해야 하며, 사업을 평가할 수 있는 기준과 방법이 객관성과 타당성을 가져야 한다. 이를 위해 수자원개발 사업시 대상이 되는 편익과 비용을 제시하여 계량화하는 것이 필요하다. 수자원사업에 따른 편익 및 비용의 대상 항목과 그 필요성은 기존에 이미 정립되어 있으나 용수공급과 홍수조절, 수력발전 등 일부 항목에 대한 계량화만이 비교적 실체적으로 연구되었을 뿐이다. 그러나 최근의 사회적 여건변화에 따라 환경개선, 관광 및 레크리에이션, 주운 등 다양한 편익항목의 계량화 방안 개발이 요구되고 있다. 본 연구에서는 댐에 의한 환경개선용수공급에 따른 하천수질개선 편익의 계량화 방안을 제시하고자 한다. 댐에 의한 하천의 수질개선은 크게 두 가지 측면에서 바라볼 수 있는데 하천유량 증대에 따른 희석효과와 수처리 시설에 의한 정수효과가 그것이다. 본 연구는 댐으로부터 공급되는 풍부한 유량을 바탕으로 희석효과에 의한 하류 수질개선 편익을 계량화하기 위한 것이다. 즉, 풍부한 유량으로 유량감소에 따른 수질악화를 막고, 희석작용에 의한 자정작용의 향상 및 이에 따른 수질개선 효과에 대한 편익이다. 본 연구는 이를 위하여 낙동강수계 내에 신규댐 건설에 의한 하류 수질개선 편익을 산정하고자 한다. 기존에는 환경개선용수 공급을 위한 댐의 편익산정에 대체댐에 의한 대체시설비용법을 적용하였으나, '댐을 대체하는 또 다른 댐'에 의한 편익산정이 갖는 이론적 모순이 제기될 수 있어 설득력을 갖기 힘든 면이 있었다. 따라서 본 연구에서는 댐의 환경개선용수 공급을 통한 수질개선 효과를 산정한 후, 이에 상당하는 효과를 환경기초시설에 의해 구현하였을 때의 비용을 계산하여 환경개선용수 공급의 편익으로 가정하는 대체시설비용법을 제시하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.583-583
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• 2016

다양한 평가지표가 반영된 복합 지수(Composite Index)는 물관리 정책의 우선순위 결정 및 정책성과의 모니터링에 유용한 도구로 사용되고 있다. 각 지표별 중요도를 나타내는 가중치는 최종 지수의 산정에 영향을 미칠 수 있으며, 그 결정방법도 Data Envelopment Analysis(DEA), Benefit of doubt Approach(BOD), Unobserved Component Model(UCM), Budget Allocation Process(BAP), Analytic Hierarchy Process(AHP), Conjoint Analysis(CA) 등 다양하다. 본 연구에서는 여러 가지 가중치 결정방법 중 통계적 방법인 주성분 분석(Principal Component Analysis, PCA)을 사용하여 Park et al.(2016)이 제시한 물관리 탄력성 지수(Water Management Resilience Index, WMRI)에 대한 가중치를 산정하여 동일 가중치를 적용한 기존 결과와 비교하였다. 물관리 탄력성 지수는 자연조건상 물관리 취약성(Vulnerability), 기존 수자원 인프라의 견고성(Robustness), 물위기 적응전략의 다양성(Redundancy)의 3가지 부지수(sub-index)는 각각 13개, 11개, 7개의 지표(Indicator)로 구성되어 있으며, 117개 중권역을 다목적댐 하류 본류유역(범주 1), 용수공급 및 유량조절이 불가능한 지류(범주 2)와 가능한 지류(범주 3)로 분류하여 적용되었다. 각 부지수별로 추출된 3개, 5개, 3개의 주성분이 전체 자료의 76.4%, 71.2%, 63.2%를 설명하는 것으로 분석되었으며 부지수별 주성분의 고유벡터(Eigenvector)와 고유값(Eigenvalue)를 계산하고 각 지표의 가중치를 산정하였다. 주성분 분석에 의한 가중치와 동일 가중치를 적용하였을 경우와 비교해보면 취약성 부지수 1.9%, 견고성 부지수 1.9%, 다양성 부지수 2.1%의 차이가 나타나며 물관리 탄력성 지수는 0.4%의 차이를 보임에 따라 Park et al.이 제시한 연구결과의 적정성을 확인할 수 있었다. 주성분 분석은 객관적인 가중치 설정을 위한 통계적 접근방법의 하나로써 다양한 물관리 정책지수 산정시 활용될 수 있을 것이며, 향후 다른 가중치 산정방법을 적용함으로써 각 방법에 따른 지수 결과의 민감도 및 장단점을 분석할 수 있을 것으로 판단된다.

• Korean Chemical Engineering Research
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• v.60 no.3
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• pp.356-362
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• 2022

Research related to hydrogen technology is being actively conducted around the world. Korea is also making great efforts to develop technology to leap forward as a hydrogen economy powerhouse. In particular, the world's No. 1 hydrogen vehicle penetration rate is proof of this. However, the construction of hydrogen refueling stations is being delayed. The biggest delay factor is the public opposition. As such, policies without public support cannot be successfully implemented and are not sustainable. Therefore, this study intends to analyze the factors affecting the acceptability of hydrogen refueling stations in favor of and against them. As a research method, the basic factors affecting acceptability were identified by reviewing previous studies, and a questionnaire was designed and investigated based on the established factors. The validity and reliability of the questionnaire were verified, and the hypothesis was verified through correlation analysis. And, using structural equation modeling, a factor model was developed on the acceptability of hydrogen refueling stations. As a result of the study, acceptability defined private acceptability and public acceptability. In the case of private acceptability, it was confirmed that the higher the attitude toward the environment, the higher the level of knowledge about the hydrogen charging station, and the lower the degree of feeling the risk of the hydrogen charging station, the higher the acceptability. In the case of public acceptability, it was confirmed that the higher the benefit, the better the attitude toward the environment, and the lower the risk-taking characteristics of the individual, the higher the acceptability. Therefore, in this study, based on the potential factors verified in previous studies, the main factors affecting the acceptance on hydrogen refueling stations were identified. And the acceptance model was developed using structural equation modeling. This study is expected to provide basic data to seek ways to improve the acceptance of public when implementing national policies such as hydrogen refueling stations, and to be used analysis data for scientific communication.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.193-201
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• 2011

The provision of traffic information plays an important role in increasing social benefit not only by saving travel time for individuals but also by improving the efficiency of road operation. VMS(Variable Message Sign) helps on-wheel drivers easily understand the road situation, and also provides real-time traffic information to people on the streets. However, it has not been sufficiently studied on how traffic information based on VMS influences on the drivers' selection of route. This study investigated how drivers use VMS traffic information and how they are satisfied with it. Then, the model of drivers' route selection was specified with the types of traffic information and the expected travel time to examine the influence on the selection of drivers' route. The model was estimated and analyzed in three types according to the condition of detour roads, and the rate of route change and the degree of sensitivity was calculated from the estimation. The results of analysis are as follows. the $1^{st}$ type model showed the 10% of route change for the travel time saving of 5minutes, and the 81.6% of route change for the travel time saving of 20minutes. The $2^{nd}$ type led to the range of route change from 14.2% to 92.7% over the 5 through 20 minutes of travel time saving. The $3^{rd}$ model resulted in the 99.1% of route change. The sensitivity of route change showed the highest for the travel time saving of 11 minutes with the $1^{st}$ type model, 9 minutes with the $2^{nd}$ type model, and 5 minutes with the $3^{rd}$ type model respectively.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.26 no.6
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• pp.33-50
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• 2023

This study is to propose the ecosystem service valuation method as a complementary or alternative tool to overcome the limitations of the contingent valuation method(CVM), typically used to assess social benefits in preliminary feasibility studies. With an increasing interest in natural and environmental restoration projects, we assessed social benefits with theses CVM and ecosystem service valuation method from a case of Janghang wetland restoration project and compared the extent of the two social benefits. For quantitative evaluation of ecosystem services, the biophysical quantity for each ecosystem service indicator was calculated and then converted into currency (KRW) units to estimate the economic value of ecosystem services. The four ecosystem regulating service indicators were selected including greenhouse gas capture/storage, air pollution, water quantity and quality regulation. The amounts of CO₂ sequestration and storage as a ecosystem's greenhouse gas regulating service in the study area were 73.04 tCO₂/yr and 5,867.53 tCO₂/yr respectively. The reduction of SO₂, one of air pollutant gases by ecosystems was calculated to be 180.27 kg/yr, the reduction of NO₂ to be 378.90 kg/yr, and the reduction of fine dust (PM10) to be 9,713.92 kg/yr. The amount of freshwater regulating service by the ecosystem was estimated to be 459,394,319ℓ/yr, and the amount of nitrogen in freshwater removed by the ecosystem was 78.00kg/yr. Study results show that the benefits derived from the CVM were KRW 227.8 billion over the 30-year analysis period and those from the ecosystem service valuation method were KRW 41.4 billion for regulatory services and KRW 148.8 billion for cultural services, totaling KRW 189.5 billion. With KRW 184.8 billion of the total costs, the benefit/cost ratio using the CVM was 1.23 and that with the ecosystem service valuation method was 1.03. This study implications include that the CVM and ecosystem service valuation method can be applied together to assess and compare social benefits for natural and environmental restoration projects.

• Korean Journal of Construction Engineering and Management
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• v.18 no.3
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• pp.52-62
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• 2017

The purpose of this study is to develope an assessment method for parking lot remodeling alternative by adopting the asset management technique. In order to identify the Level of Service(LOS) and the Evaluation Measurement(EM), literatures was implemented which documented the consideration of parking lot plan, needs of the apartments' tenant, and various design standards. In addition, the authors conducted a three-time delphi survey for the identified 5 LOS and 19 EM to evaluate suitability and necessity of them and to collect additional opinion of experts. The LOS of parking lot were categorized into 5 areas such as Environmental effect and Convenience, Accessibility and so on. The 19 EM were determined to estimate the LOS quantitatively. The researchers analyzed the degree of importance of LOS and EM by using the Analytic Hierarchy Process (AHP) method. But construction cost was excepted from the analysis, because it is used as an independent variable in alternative assessment. In conclusion, the authors proposed the estimation criteria for EM, and the method and process for alternative assessment be performed to benefit-cost analysis using the LOS variation and construction cost. The assessment method for parking lot remodeling alternative was demonstrated effective to assess the parking lot remodeling alternative by case-study. This study has a academic significance by adopting the asset management techniques in the area of the parking lot remodeling. And the assessment method is expected to help deciding a reasonable remodeling alternative of parking lot, as it ensures the diversity for remodeling of the parking lot and reflects the needs of the occupant.

• Journal of Korean Society of Transportation
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• v.30 no.1
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• pp.19-30
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• 2012

The majority of daily travel demands concentrate at particular time-periods, which causes the difficulties in the travel demand analysis and the corresponding benefit estimation. Thus, it is necessary to consider time-specific traffic characteristics to yield more reliable results. Traditionally, na$\ddot{i}$ve, heuristic, and statistical approaches have been applied to address the peak-hour ratio. In this study, a hybrid clustering model which is one of the statistical methods is applied to calculate the peak-hour ratio and its duration. The 2009 national 24-hour traffic data provided by the Korea institute of Construction Technology are used. The analysis is conducted dividing vehicle types into passenger cars and trucks. For the verification for the usefulness of the methodology, the toll collection system data by the Korea Express Corporation are collected. The result of the research shows lower errors during the off-peak hours and night times and increasing error ratios as the travel distance increases. Since the method proposed can reduce the arbitrariness of analysts and can accommodate the statistical significance test, the model could be considered as a more robust and stable methodology. It is hoped that the result of this paper could contribute to the enhancement of the reliability for the travel demand analysis.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.12a
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• pp.4-15
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• 2005

Methylmercury (MeHg) is an environmental pollutant with neurotoxic effects on the central nervous system. The major exposure route of MeHg to humans is via consumption of fish and shellfish which accumulate the chemical through the food web in an aquatic environment. Hair mercury level is an excellent marker for MeHg exposure. We have been conducting a survey on hair mercury contents among general populations from 14 districts to estimate the current Japanese MeHg exposure level. Total mercury levels of all hair samples collected (12923 in total) were analyzed by the oxygen combustion-gold amalgamation method using an atomic absorption mercury detector. Multiple regression analysis revealed that mercury levels were significantly correlated with several covariates, such as sex, age, the amount of daily intake of total fish/shellfish, a preference for certain fish such as tuna or bonito, and artificial waving. The geometric means for the population without artificial waving were 2.47 and 1.65 ${\mu}g/g$ for males (n = 5623) and females (n = 3470), respectively. Hair mercury levels varied with age, and the variations were more significant in males. Since the difference between sexes was not evident at younger ages, some hormonal control might also be involved in the mercury uptake by human hair. The average mercury levels in our hair samples varied among the sampling districts. Tuna is a major carnivorous fish with high mercury accumulations that is often consumed in Japan. The amount of fish consumption and the preference rate far tuna would appear to be responsible far the regional variation in hair mercury levels in Japan. Recently, a provisional tolerable weekly intake (PTWI) of MeHg was revised by 61st JECFA to 1.6 ${\mu}g/kg/week$, which was about half that of the Japanese standard, and corresponded to a hair level of 2.2 ppm. The distribution of hair mercury levels in Japanese populations in the present study indicated that 25% of the Japanese females of child-bearing age were estimated to be exposed to MeHg over the PTWI level. This would reflect the high Japanese consumption of marine products. However, not only mercury contamination, but also the nutritional benefit may have to be considered when discussing the risk involved in the current level of fish and shellfish consumption in Japan.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.117-122
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• 2018

A large-capacity three-phase system air conditioner recently includes an inverter circuit to reduce power consumption. The inverter circuit uses a DC voltage that comes from DC-link power capacitor with the function of rectifying, which means AC voltage to DC voltage using a diode. An electrolytic capacitor is generally used to satisfy the voltage ripple and current ripple conditions of a DC-link power capacitor used for rectifying. Reducing the capacitance of the capacitor decreases the size, weight, and cost of the circuit. This paper proposes an algorithm to reduce the input ripple current by combining the minimum point estimation phase locked loop (PLL) phase control and the average voltage d axis current control technique. When this algorithm was used, the input ripple current decreased by almost 90%. The current ripple of the DC-link capacitor decreased due to the decrease in input ripple current. The capacitor capacity can be reduced but the electrolytic capacitor has a heat generation problem and life-time limitations because of its large equivalent series resistance (ESR). This paper proposes a method to select a film capacitor considering the current ripple at DC-link stage instead of an electrolytic capacitor. The capacitance was selected considering the voltage limitation, RMS (Root Mean Square) current capacity, and RMS current frequency analysis. A $1680{\mu}F$ electrolytic capacitor can be reduced to a $20{\mu}F$ film capacitor, which has the benefit of size, weight and cost. These results were verified by motor operation.