• Journal of Korean Society of Water and Wastewater
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• v.23 no.3
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• pp.321-329
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• 2009

I/I(Infiltration/Inflow) characteristics should be studied to achieve I/I reduction which is a main object of sewer rehabilitation. However, The scientific and practical studies which are based on actual survey within the country are not thorough going enough. The earlier studies were limited because of a short research period and specific region. Thus, In this study, a formula is deduced by intensive correlation analysis between defective number and I/I volume in sewer pipe. It can be used as preliminary data when the project established for cost-effective pipe rehabilitation. The study shows that the researched region have a faulty point at every 9.3m on average and prove correlation between defective number and I/I volume in sewer pipes. Thus, this study can improve the investigation system and estimate the volume of the pipe rehabilitation, when site investigations for rehabilitation have been conducted.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.20 no.1
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• pp.26-33
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• 2012

Competition between air transportation and railways has grown fiercer in major countries around the world with the rise of high-speed railways. In South Korea, air passenger travel has been rapidly decreasing since the initial launch of the Seoul-Pusan KTX line in 2004 and second opening that followed in 2010. Further expansion of the high-speed railway is expected. At present, research efforts to verify the validity of constructing an underwater express railway tunnel between Ho-nam and Jeju Island are taking place. Considering the possible high speed railway connection between Seoul and Jeju Island, this thesis has analyzed the choice behavior of existing passengers of the major and low-cost carriers. For this, Stated Preference (SP) research has been performed for three variables, including fare, travel time and the number of runs, to estimate the substitution rate of each of the three variables. Binomial Logit Model has been estimated with the obtained data. The estimation of the model has found that airline passengers of major and low-cost carriers are willing to pay approximately 7,200 KRW and 5,000 KRW, respectively, to reduce travel time by one hour. If the number of runs in one day increases, it has been estimated that the passengers are willing to pay additional fares of about 390 KRW and 30 KRW, respectively. On the other hand, the substitution rate between the number of runs and the travel time was found to be somewhat insignificant. If the construction of the Seoul-Jeju line progresses in the future, this study could be used as preliminary data for determining fares, travel time and the number of runs.

• Journal of Environmental Policy
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• v.9 no.1
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• pp.31-55
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• 2010

This study aims to estimate potential climate change damage in Korea using the PAGE model. This study reviewed previous a reasearch to compare relative sensitivity to climate change in Korea and other regions to generate climate change damage function. It was found that sensitivity to climate change in Korea is similar to other Organization for Economic Cooperation and Development (OECD) countries. This study estimated climate change impact for three scenarios. If no action is taken, climate change damage cost in Korea could reach US$ 12,928 ~ 57,900 M. Cumulative Net Present Value (NPV)of climate change impact from 1990 to 2100 would be between US$ 143,226 ~ 921,701 Mdepending on emission scenarios. However, this result should be interpreted with caution as it draws its damage function based on only a few available references. Results also showed that an adaptation policy could decrease the degree of climate change impact significantly. If an adaptation policy is implemented, climate change impact will be decreased by US$ 11,355 million dollars in Korea in 2100.

• Magazine of the Korean Society of Agricultural Engineers
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• v.18 no.1
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• pp.4079-4086
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• 1976

In many reservoir projects, economic considerations will necessitate a design utilizing surcharge. Determination of the most economical combination of surcharge and spillway capacity for a given spillway crest level will require flood routing studies and economic studies of the dam-reservoir-spillway combinations. Many methods of actual flood routing have been devised, each of them with its advantages and disadvantages. Some of these methods are listed below: (1) Arithmetical trial-and-error method. (2) Modified Puls' method (3) Cheng's graphical method (4) Horton's arithmetical method (5) Ekadahl's arithmetical method (6) Digital computer programming. For the purpose of preliminary design and cost estimating of dams and spillways, it is often required to estimate, for a given design flood and spillway crest level. the approximate values of two among the three characteristics of the spillway spillway length, maximum discharge and surcharge depth at maximum discharge, when one of these quantities is given. As is well known, the outflow hydrograph for an ungated overflow spillway assumes the form of a wave-shaped curve with a minimum point for Q=o At zero time and a maximum point for Q=Qmax at its intersection with the falling leg of the inflow hydrograph (see Fig. 4) The shaded area between the inflow and outflow hydrographs represents at the approximate scale the temporary retention Vt. In line with the remarks, draw by free hand the assumed outflow hydrograph with its maximum point for the given Qmax (see Fig. 4) and by planimetration find Vt. From the reservoir capacity curve (Fig. 3) find Vs for the given spillway crest level and make V=Vs+Vt. From the above curve find surcharge water elevation for V and surcharge depth Hmax over spillway crest. From the discharge formula compute {{{{L= { Q} over { { CH}^{3/2 } } }}}} The methed provides a means for a quick and fairly accurate estimation of spillway capacity.

• Journal of the Korean Geotechnical Society
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• v.27 no.6
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• pp.27-37
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• 2011

Recently, pressure grouting is widely being used in construction site for strength improvement of ground and water proof, reinforcement and so on. It is necessarily required to estimate an appropriate injection pressure and injection time for economical and reasonable construction in the site through the size and shape of the hardened grout measured according to ground condition. However, sampling for the hardened grout is time-consuming and needs high cost on preliminary test in the site. The system which could predict the size and shape of the hardened grout does not exist until now. Thus, numerical method based on VOF method and porous model was used for the calibration chamber injection test with injection pressure (50 kPa, 100 kPa, 150 kPa) in this study. The results indicate that the numerical technique based on VOF method and porous model among CFD analysis is expected to be a basic study for the prediction of the behavior and solidification of pressure grouting.

• Journal of the Korea Institute of Building Construction
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• v.22 no.3
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• pp.269-280
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• 2022

With property values of buildings rising, interior construction works are also increasing globally. Interior construction technology has developed into building information modeling(BIM) that can estimate and integrate material quantities. Two-dimensional(2D) drawings and three-dimensional (3D) modeling are becoming a trend owing to the demanding on-site cost and process. 2D drawings and 3D modeling have both advantages and disadvantages that give rise to defects during interior construction work. The field problems, 2D drawings, 3D modeling, and preliminary risk factors of interior construction work were analyzed to identify real problems. Based on the problem analysis, various problems were derived, such as (1) communication with purchasers, (2) communication with workers, and (3) comprehension of the drawings. In this study, a checklist for quality improvement of interior construction was proposed to address the aforementioned issues.

• 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.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1512-1512
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• 2001

The University of Cordoba conducts since 1991 a breeding program to obtain new olive cultivars from intraspecific crosses. The objective is to obtain new early bearing and high-quality cultivars. In plant breeding, many seedlings must be tested to increased the chance of getting desirable genotypes. Therefore, fast, cheap and accurate methods of analysis are necessary. The conventional laboratory techniques are costly and time-consuming. Near Infrared Spectroscopy (NIRS) can satisfy the characteristics requested by plant breeders and offers many advantages such as the simultaneous analysis of many traits and cheap cost. The objective of this work was to asses the performance of NIRS to estimate oil fruit components (fruit weight, flesh moisture, flesh/stone ratio and oil flesh content in dry weight basis) and fatty acid composition in olive fruit. Genotypes from reciprocal crosses between ‘Arbequina’, ‘Frantoio’ and ‘Picual’ cultivars have been used in this study. A total of 287 samples, each from a single plant, were scanned using a DA-7000 Diode Array VIS/NIR Analysis System (Perten Instruments), which covers the visible and NIR range from 400-1700 nm. All samples were analysed for fatty acid composition (gas chromatography) and 220 for oil fruit components (oil content by nuclear magnetic resonance), 70% and 30% of samples were randomly assign for the calibration and validation sets respectively. The preliminary results shows that calibration for palmitic, oleic and linoleic acids were highly accurate with calibration and validation values of $r^2$ from 0.85 to 0.95 and 0.76 to 0.91 respectively. Calibration for palmitoleic and estearic acids were less accurate, probably because of the narrow range of variability available for these fatty acids. For the oil fruit components, calibration were high accurate for flesh moisture and oil flesh content in dry weight basis ($r^2$ higher than 0.90 in both calibration and validation sets) and less accurate for the other characteristics evaluated. The first results obtained indicate that NIRS analysis could be an ideal technique to reduce the cost, time and chemical wasted necessary to evaluate a large number of genotypes and it is accurate enough to use for pre-selecting genotypes in a breeding program.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.3
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• pp.73-82
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• 2012

In order to carry out efficient investment and successful business in national geo-spatial industry, economic assessment on the field of 3D geo-information has recently emerged as a serious issue. Therefore, this study is intended to offer cost-effective evaluation scheme which are proper for 3D geo-spatial information, especially focusing on development of orthophoto and DEM. The study is organized as follows. The first section clarifies preliminary rules for feasibility by defining target work and category in order to estimate benefit. Then, this paper will be limited to consideration of production of digital mapping for target business which is expected to create high value and its benefit from cost reduction is suggested. Drawing from the AHP(Analytic Hierarchy Process) methods, this study comprehensively described final result and implication to examine business value. Consequently, this study can suggest economical evaluation methods on 3D geo-spatial information industry, which takes up a considerable part of immaterial benefit and has difficulties in economic assessment and estimation. preventing a variety of errors in system operation in advance.

• Journal of Environmental Policy
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• v.12 no.4
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• pp.71-92
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• 2013

Unlike general public investment projects, when it comes to environmental public investment projects, there is a gap between those who pay the costs, and those who receive the benefits. This is because of the long term nature of environmental investments, which entails that the majority of the costs are paid by the current generation, while the benefits are reaped by future generations. Because of this, when the social discount rate is set at a standard, singular rate, an issue of relative underestimation of the benefits reaped by future generations may occur during the analytic process. This paper begins with the recognition of this problem, and attempts to estimate a suitable social discount rate that can be applied to environmental investment projects. Taking into account recent economic situations, the social discount rate is currently being estimated at between 2.9 ~ 4.9%. Also, this paper used preliminary feasibility studies that took place so far, to analyze the standard pattern of benefit generation. This revealed that alterations in social discount rates can bring significant changes in economic feasibility test results. Simulation results showed that roughly 6% of B/C ratios could be increased by 1%p. resulting in a decrease in social discount rates. Also if we use hyperbolic discount rates, instead of using the current singular rate, there would be a meaningful increase in the benefits for the future generation.