• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.52-60
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• 2018

In the construction industry, attempts to evaluate the environmental impact of products through life cycle assessment (LCA) approach has been on the rise. However, the domestic construction industry needs to make rapid decisions due to limited budget and schedule, so it is difficult to carry out a review of the environmental load on all resources. The decision-making process requires information on the major influence factors that should be focused on to reduce environmental load. And this information should be quantified so that it can be linked to environmental impact assessment. In this study, the LCA results of road construction cases were analyzed to provide such information. As a result, diesel, ready-mixed concrete, urethane-based paint, aggregate, and asphalt concrete were found to be the main factors that generated 93.17% of the environmental load in the earthwork type of road project. The total environmental cost caused by these affecting factors when constructing 1 km of earthwork type of road project is 242 million won. The analysis also shows that a 10% reduction in the amount of ready-mixed and asphalt concretes can reduce carbon emissions by 5.02% and 2.28% while reducing environmental costs by 11 million won per kilometer. In order to reduce carbon emissions of the earthwork type of road project, it is necessary to actively develop and introduce new methods and eco-friendly materials to reduce the overall use of ready-mixed concrete and asphalt concrete.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.2
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• pp.468-474
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• 2017

A test service for the weapon systems evaluation is one of the most important processes during the weapon systems acquisition or development life cycle. Before completion of weapon systems development, the appropriate evaluation test can reduce risk and expense which might be expected during weapon systems development procedure. In this paper, it is suggested that a probabilistic prediction method based on Monte Carlo simulation for how much the annual weapon systems evaluation test excution ratio can be reached compared to the yearly initial planned test quantity. And then a weapon systems evaluation test quantitative management scheme is suggested to assist decision making for the test schedule manager who can arrange monthly test schedule based on the prediction result of annual test excution ratio. And the proposed method is applied for the weapon systems evaluation firing test data of the 8th directorate, Agency for Defense Development(ADD). And also the application result is examined.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.7 no.4
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• pp.257-266
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• 2002

To estimate the nitrogen budget and assess the purification function of a tidal flat ecosystem, a field survey was carried out at Hajeon tidal flat in Gomso Bay, the southern part of Byeonsan Peninsula, Chollabuk-do, Korea. A study area of 3.0$\times$4.5 ㎢ was established on the tidal flat and the concentrations of chlorophyll-a, DIN, DON, and TN were measured in the water column during the period of April 17-18, 1999: From the budget analysis, the loss rate of Chl-a was estimated to be -0.05 mg Chl/㎡/hr, which is approximately 7% of that at Issiki tidal flat in Aichi Prefecture, Japan. The lower loss rate of Chl-a in the study area was attributable to the lower standing crop of phytoplankton, the lower temperature that may reduce metabolic rates of biotic components and the lower biomass of macrobenthos in the study area. Over the 13.5 ㎢ of study area, Hajeon tidal flat removed 8.36$\times$10$\^$2/ kg N/day of TN, 5.36$\times$10$\^$3/ kg N/day of PON and 1.62$\times$10$\^$2/ kg N/day of phytoplankton-related PON, showing that the tidal flats may play an important role in removing nitrogen in coastal waters. The removal rate of PON, compared to the removal cost of the existing waste water treatment facilities, indicates that the economic value of the purification function of Hajeon tidal flat (13.5㎢) may be more than that of two large facilities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.669-679
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• 2016

Architectural firms that would like to adopt the BIM are currently in an unfavorable position because of reduced orders, polarization of orders, and low price design. This study was conducted to evaluate plausible methods for supporting introduction of BIM into small sized firms. Before suggesting plans for support, we analyzed support projects and laws relating to support for small sized firms, after which we conducted a survey of small sized firms that support the project. The survey was completed by 242 architects and consisted of questions regarding the following aspects: current status and problems associated with BIM utilization, preference of certain policies for BIM introduction support, and reasonable level of support. After the survey, it was concluded that architectural firms are willing to use BIM and agree with the need for financial support for BIM program purchase and education, as well as to support BIM experts and fund low interest loans. In conclusion, it is proposed that support plans for small sized architectural firms in the areas of BIM introduction consulting, financial funding for the introductory process, provision of education and experts, order support, and promotions for accomplishment be provided.

• The Journal of Engineering Geology
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• v.31 no.3
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• pp.343-355
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• 2021

Agricultural reservoirs seek human convenience by supplying agricultural water and providing flood damage effects and rest areas at the same time, but preventing them from aging reservoirs and earthquakes is important. The safety of levees is influenced by field material properties such as soil parameter values of the granular materials that make up the levees, but since precision safety diagnosis or general literature values are diverted, the final safety factors are limited to material properties alone. Since safety factors are determined by physical characteristic values and embankment shapes and have a significant impact on safety factors, accurate contemplation is required when examining reinforced cross sections. Therefore, this study analyzed the case of reasonable and economical reinforcement intersections when designing '◯◯reservoir' in Goheung-geun, Jeollanam-do using the GEP-SLOPE program to enable rational economic design of reinforcement intersections through repeated reviews. As a result of reducing and analyzing the first, second, and third seismic reinforcement of the levees, it was confirmed that the safety ratio was secured even with a significantly smaller amount of reinforcement than the first, second, and lower slopes by obtaining design standards of 1.20. In addition, when determining all seismic reinforcement cross-sectional shapes, it was confirmed that the shape that reinforces only the lower side rather than the upper side of the slope and the entire slope was economical with minimized cross-sectional reinforcement.

• MARITIME LAW REVIEW
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• v.29 no.2
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• pp.115-144
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• 2017

The impact of the global financial crisis, which began in the United States in 2007, had a major impact on the domestic shipping and shipbuilding industries. In this regard, the domestic shipyard has established an order-taking strategy in several ways as an alternative to lowering the amount of construction of commercial vessels due to deterioration of the shipping industry, and selected industrial sector was the offshore plant sector. However, the domestic shipyard has under performed the offshore plant in order to just increase sales and secure work without any risk analysis for EPC contracts. As a result, the shipyard has been charged more than the initial contract price with the offshore plant contractor, or the shipyard has become a legal issue requiring payment of liquidated damages due to delays in delivery of the product. The main legal disputes are caused by the thorough risk analysis and the inexperience of process control that can occur during offshore plant construction. and In particular, there is no sufficient review of the unequivocal provisions in the contract as an element of risk management. There is no human resource to review these contractual clauses. Therefore, this study identifies the existence of specific risks that could lead to delays in offshore plant construction, and examined the existence of any unequivocal clauses in contracts for offshore plant construction. and also discussed how the toxic clause applies to the actual parties and how the concrete risk factors in the construction contracts are transferred and expressed by referring to the interviews with the project manager of the domestic shipyard and the previous research. As a result, This paper examined the legal liability of the contracting parties regarding delayed delivery of the products due to the offshore plant construction contract. And to improve the domestic shipbuilding industry.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.111-118
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• 2020

The U-shaped composite beam used in this study consist of a reinforced concrete structure, a beam steel structure supporting the slab, a reinforced concrete structure, and a U-shaped steel plate. The U-shaped composite beam was developed for the purpose of using it as a parking lot because it is highly constructible and has low floor height and long span. For the improvement of constructivity, the U-shaped composite beam ends are planned with standardized H-shaped steel and connected directly to the columns, and the middle of the U-shaped composite beam consists of U-shaped steel plates folded in U-shaped form using thin steel plates (t=6) instead of H-shaped steel. In the middle of the composite beam, where U-shaped steel plates are located, the depth of U-shaped beam may be planned to be small so as to satisfy the height limit of the parking lot. It is important to grasp the structural performance according to the change of depth because low beam depth is advantageous for the reduction of the floor height, but it is a inhibitor to the structural behaviors of U-shaped composite beam. In addition, since U-shaped composite beams are a mixture of steel frame structures, reinforced concrete structures and U-shaped steel plates, securing unity has a great influence on securing structural performance. Therefore, in this study, a structural experiment was conducted to understand the structural performance according to the depth change for U-shaped composite beam. A total of three specimens were planned, including two specimens that changed the depth using a criteria specimen planned for a general parking lot. The results of the experiment showed that the specimens who planned the depth greatly had better structural performance such as yield strength, maximum strength, and energy than the standard specimen.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.121-131
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• 2004

Removal efficiencies of soil washing and soil improvement processes to remediate farmland soils and stream deposits around Goro abandoned mine were investigated with batch and column experiments. For As-contaminated farm-land soils around Goro mine, batch tests to quantify As extraction rate from contaminated soils and lime treated contaminated soils were performed. The contaminated soil mixed with lime decreased As extraction rate less than one fourth, suggesting that the soil improvement method mixed with lime dramatically decrease As extraction rate. A storage dam will be constructed in the lower part of the main stream connected to Goro abandoned mine and the amount of As extracted from the bottom soils of reservoir could be the main source to contaminate water of reservoir. The decrease of As extraction amount from the bottom in reservoir, caused by the application of the soil improvement method was investigated from the physically simulated column experiment and results showed that As extraction rate decreased to one forty when 1％ lime mixed soil improvement was applied to contaminated soils. For contaminated stream deposits connected Goro mine, the removal efficiency of the soil washing method was investigated with batch experiments. Hydrochloric acid, citric acid, acetic acid and distilled water were used as soil washing solution and 0.01, 0.05, 0.1, 0.5, 1.0 N of washing solution were applied to extract As. When washing with 0.05 N of hydrochloric acid or citric acid, more than 99.9% of As was removed from stream deposits, suggesting that As contaminated stream deposits around Goro mine be successfully remediated with the soil washing process. Total volumes of contaminated soils and deposits needed for remediation were calculated based on three different reme-diation target concentrations and the operation cost of soil washing for calculated soil volumes was estimated. Results from this research could be directly used to make a comprehensive countermeasure to remediate contaminated area around Goro mine and also many contaminated areas similar to this research area.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.7
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• pp.820-825
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• 2007

Earthworm casting was the natural fertilizer that contained high concentrations of nutrients such as nitrogen, phosphate and potassium and of over $10^8$ CFU/ml of microorganisms. Greater than 80% of feed was excreted through the fermentation by the intestinal enzyme, after worm had eaten feeds such as fallen leaves and rotten roots under the ground. Also, the soil structure of casting was known to be very efficient in the aspects of the porosity, the water permeability, and deodorizing activities. In this research, the biofilter packed with a biomedia made of casting and waste polyurethane foam, a binder, which helped to improve the durability and perpetuity of casting, was investigated to degrade malodorous hydrogen sulfide gas. The biomedia had no need of extra supply of nutrients and of microbial inoculations. On the beginning of the operations, it showed 100% removal of hydrogen sulfide gas without lag phase. At SV of 50 $h^{-1}$, hydrogen sulfide gas from the outlet of the biofilter was not detected, when inlet concentration increased to 450 ppmv. After that, removal efficiency decreased as increasing inlet hydrogen sulfide concentration. Hydrogen sulfide removal was maintained at almost 93% until inlet concentration was increased up to 950 ppmv, at which the elimination capacity of $H_2S$ was 61.2 g $S{\cdot}m^{-3}{\cdot}h^{-1}$. Maximum elimination capacity guaranteing 90% removal was 61.2, 65.9, 84.7, 89.4 g $S{\cdot}m^{-3}{\cdot}h^{-1}$ at SV ranging from 50 $h^{-1}$ to 300 $h^{-1}$, but was 59.3 g $S{\cdot}m^{-3}{\cdot}h^{-1}$ at SV of 400 $h^{-1}$. The results calculated from Michaelis-Menten equation revealed that $V_m$ increased from 66.04, 88.96, 117.35, 224.15, to 227.54 g $S{\cdot}m^{-3}{\cdot}h^{-1}$ with increasing space velocity in the range of 50 $h^{-1}$ to 400 $h^{-1}$. However, saturation constant$(K_s)$ decreased from 79.97 ppmv to 64.95 and 65.37 ppmv, and then increased to 127.72 and 157.43 ppmv.

• The Korean Journal of Malacology
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• v.15 no.1
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• pp.31-39
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• 1999

This study was aimed to describe the population dynamics and secondary production of Tapes philppinarum on Chohwa and Toksan tidal flats in Kwangyang Bay, from June 1994 to July 1995. The size distributions in shell length showed bimodal patterns from June 1994 to April 1995. Thereafter the distribution changed to the passage of time, indicating an increase in shell length. The mean densities decreased gradually with month. Chohwa A sustained highestdensity, followed by Chohwa B, Toksan C, and Toksan D. The recruitment of new year class occurred first on the upper tidal flat, and then moved to the lower tidal flat. The mean biomass in flesh dry weight of each year class increased in spring just before the spawning period, and thereafter decreased progressively. Annual mean biomass wasrecorded as 170.7 g m$\^$-2/ at Chohwa A, 220.7 g m$\^$-2/ at Chohwa B, 21.8 g m$\^$-2/ at Toksan C, and 45.2 g m$\^$-2/ at toksan D. Annual productions of Ruditapes philippinarum were estimated as 259.72 g m$\^$-2/ yr$\_$-1/ at Chohwa A, 359.79 g m$\^$-2/ yr$\_$-1/ at Chohwa B, 45.02 g m$\^$-2/ yr$\_$-1/ at Toksan c, 68.88 g m$\^$-2/ yr$\_$-1/ at Toksan D. Annual productions were much higher on Chohwa tidal flat than those on Toksan tidal flat. While P:B ratio were higher on Toksan tidal flat as 1.70 than those on Chohwa tidal flat as 1.58. In conclusion, the Chohwa tidal flat showed higher biomass and producion of Ruditapes philippinarum, whereas the Toksan tidal flat showed higher P:B ratio. The total amount of potential food might influence on the density, biomass nad produciton, whereas the amount of food and space per individual might influence on the growth rate and P:B ratio.