• Journal of the Korea Institute of Building Construction
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• v.11 no.3
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• pp.247-255
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• 2011

Currently, there is database for per unit requirements of major construction materials in terms of energy consumption and $CO_2$ emission based on the input-output table published by the Bank of Korea in 2000, but no database for per unit requirements based on input-output tables was published in 2005 and 2007. The purpose of this study was to calculate the unit requirement values of major construction materials in terms of energy consumption and $CO_2$ emission generated by using the input-output tables published in 2005 and 2007. To estimate the unit requirement values, a database building method with the input-output tables was adopted by selecting 16 types of construction materials in wide use on construction sites. When the study results were compared with existing unit requirement values based on the input-output table of 2000, there were small discrepancies, from which it can be interpreted that the method used in the study is reasonable. Unit requirement values estimated based on input-output tables of 2005 and 2007 tended to decrease, and the highest value of energy consumption and $CO_2$ emission were found in the materials using cement and rebar.

• Korean Journal of Construction Engineering and Management
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• v.14 no.2
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• pp.96-107
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• 2013

Tower crane hoisting plan is one of the key element for the success of entire High-Rise Building construction. Hoisting time is the basic factor to appropriate hoisting plan which need to the hoisting load estimate and tower crane selection. With this reason, accurate hoisting time is needed to the proper hoisting plan. The current hoisting time estimation for High-Rise Building focus on the hoisting cycle time estimation with historical data. However, this method underestimated the external influences like environmental factor. Thus, this paper aims to develop the hoisting time estimation model with discrete event simulation which include the wind influences with certain height. According to the simulation result, the hoisting time which applied wind influence is increasing with height growth. Because of the high speed wind, the upper area of building has more operation delay time than the mechanical operation time. Seoul, the research area, has the most fastest wind speed on April and the least on October. Due to these differences of wind speed, the hoisting time is estimated with significant differences between April and October. This hosting time estimation model would be used for estimating the influence of wind. Moreover, this could apply to make the realistic hoisting plan.

• Korean Chemical Engineering Research
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• v.52 no.4
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• pp.503-515
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• 2014

A lot of existing wastewater treatment plants (WWTPs) are rebuilt or retrofitted for advanced wastewater treatment processes to cope with reinforced effluent criteria of nitrogen and phosphorous. Moreover, how to treat the wasted sludge from WWTPs has been also issued since the discharge of the wasted sludge into ocean is impossible from 2011 due to the London Convention 97 protocol. These trend changes of WWTPs get a motivation to assess environmental and economic impacts from the construction stage to the waste stage in WWTPs. Therefore, this study focuses on evaluation of environmental and economic impacts of the advanced wastewater treatment processes and waste sludge treatment process by using life cycle assessment. Four advanced wastewater treatment processes of Anaerobic/Anoxic/Oxic ($A_2O$), 5 stages-Bamard Denitrification Phosphate (Bardenpho), Virginia Initiative Plant (VIP), and Modified University of Cape Town (MUCT) are chosen to compare the conventional activated sludge (CAS) and three waste sludge treatment methods of land fill, incineration, and composting are used. To evaluate environmental and economic impacts of each advanced wastewater treatment processes, life cycle assessment (LCA) and life cycle cost (LCC) are conducted based on International organization for standardization (ISO) guidelines. The results clearly represent that the $A_2O$ process with composting shows 52% reduction in the environmental impact than the CAS process with landfill. On the other hand, the MUCT process with composting is able to save 62% of the life cycle cost comparing with the CAS process with landfill. This result suggested the qualitative and quantitative criteria for evaluating eco-environmental and economic technologies of advanced treatment processes and also sludge treatment method, where their main influence factors on environmental and economic impacts are analyzed, respectively. The proposed method could be useful for selecting the most efficient and eco-friendly wastewater treatment process and sludge treatment method when retrofitting the existing WWTPs to advanced treatments.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.297-305
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• 2023

The recycled irrigation is a type of irrigation that uses downstream water to fulfill irrigation demand in the upstream agricultural areas; the used irrigation water returns back to the downstream. The recycled irrigation is advantageous for securing irrigation water for plant growth, but the returned water typically contains high levels of nutrients due to excess nutrients inputs during the agricultural activities, potentially deteriorating stream water quality. Therefore, quantitative assessment on the effect of the recycled irrigation on the stream water quality is required to establish strategies for effective irrigation water supply and water quality management. For this purpose, a watershed model is generally used; however no functions to simulate the effects of the recycled irrigation are provided in the existing watershed models. In this study, we used multi-reservoir model coupled with the Hydrological Simulation Program-Fortran (HSPF) to estimate the effect of the recycled irrigation on the stream water quality. The study area was the Gwangok stream watershed, a subwatershed of Gyeseong stream watershed in Changnyeong county, Gyeongsangnam-do. The HSPF model was built, calibrated, and used to produce time series data of flow and water quality, which were used as hypothetical observation data to calibrate the multi-reservoir model. The calibrated multi-reservoir model was used for simulating the recycled irrigation. In the multi-reservoir model, the Gwangok watershed consisted of two subsystems, irrigation and the Gwangok stream, and the reactions (plant uptake, adsorption, desorption, and decay) within each subsystem, and fluxes of water and materials between the subsystems, were modeled. Using the developed model, three scenarios with different combinations of the operating conditions of the recycled irrigation were evaluated for their effects on the stream water quality.

• Journal of the Korean Society for Marine Environment & Energy
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• v.12 no.2
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• pp.75-83
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• 2009

In order to understand the impacts of the construction of artificial sea dikes on carbon cycle in Samangeum area being a closed environment after April, 2006, we had measured suspended particulate matters, particulate and dissolved organic carbon in the surface water of inner Saemangeum dike from 2003 to 2006. The significant inputs of suspended particulate matter and organic carbon were mainly occurred during the wet season which suggests that most organic matter loading is concentrated within a short period of time inside the dike. The concentrations of particulate matter and organic carbon have gradually increasing every year inside of dike from the Mangyeong river estuary to Saemangeum dike, which has been closed since 2003 after the construction of the 4th dike. The particulate organic carbon increased due to the phytoplankton blooms by eutrophication. If the large portion of particulate organic matter produced in the surface water sink to the bottom sediment, this will cause the anoxic condition in this closed environment.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1264-1269
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• 2008

최근에 이르러 농촌 인구의 도시유입으로 도시의 주거공간이 절대적으로 부족해지고 있으며, 이는 대도시의 아파트 가격 상승을 유발하는 등 부수적인 사회/경제적 문제를 일으키고 있다. 정부나 지방자치단체에서는 이러한 문제를 해결하기 위하여 대규모의 신도시 개발계획을 추진하고 있으며, 이러한 신도시 개발은 도시화로 인하여 환경적, 수문학적으로 영향을 미치는 것으로 조사되고 있으며 도시물순환계는 강우가 지표에 도달 한 후 바로 하천으로 유출되는 것과 침투하여 서서히 유출하는 자연경로 그리고 상수도 및 하수도를 통해 하천으로 배수되는 인공적 경로에 의해서 형성된다. 일반적으로 신도시 개발 전후의 수문순환을 평가하는 방법 중의 하나는 개발예정지에 대한 장단기의 수문 관측을 통하여 개발 전과 개발 후의 유출특성과 수질부하를 정량적으로 비교하는 것이다 (한국건설기술연구원, 2004). 따라서 본 연구에서는 행정중심 복합도시 물순환 해석을 하기 위해 대상유역을 100m 크기의 정방형 격자로 구분하고 기상조건, 지표면 조건, 하천, 토양, 지하 대수층, 농업용수 등의 광범위한 입력 자료를 구축한 후 이를 물리적인 기반의 공간분포모형인 WEP 모형에 적용하여 개발 전 홍수 및 유출특성을 규명하고자 한다. 이를 위해 대상지역에 대한 장기적인 수문모니터링 자료를 바탕으로 1996년에서 2007년 까지 모의 하여 실측자료가 있는 $2006{\sim}2007$년을 대상으로 비교한 결과 일부 갈수기 자료를 제외 하고, 전반적인 높은 상관성을 나타냈다. 하지만 일부 홍수위에서 금강으로 부터의 배수위 영향으로 인한 차이가 발생해 추가적인 검토가 필요하며, 본 연구에서 도출된 결과들은 향후 도시유역에서의 수자원 분배와 물자원 관리 등의 적응전략을 수립하는데 있어 본 연구가 도움이 될 것이라고 판단한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3587-3595
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• 2015

Low-carbon eco-friendly precast concrete (PC) box structure has been recently was developed as an low-cost infrastructure of near-surface transit system. The concrete of PC box was manufactured by industrial byproducts such as ground granulated blast furnace (GGBF) slag, flyash and rapid-cooling electric arc furnace (EAF) oxidizing slag, its mechanical property and durability were estimated in this study. Based on the mechanical and durability tests, it is found that low-carbon eco-friendly concrete shows high initial compressive strength, more than 90% of design strength (35MPa), and high resistance to salt-attack, chemical- attack and freeze-thaw. Therefore, low-carbon eco-friendly PC box concrete technology is expected to contribute to the railway with low environmental impact.

• Journal of the Korea Institute of Building Construction
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• v.21 no.4
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• pp.281-291
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• 2021

To reduce the environmental load of the construction industry, there is a need to minimize construction and demolition by strengthening the eco-friendliness of building materials and extending the durable lifespan. Therefore, while many Hanok roof finishing methods have been proposed to address these problems, the current trend is to use the existing method due to issues such as economic feasibility, weight, and durability. The manufacturing method of clay roof tiles used as roofing materials for Hanok buildings is optimized by using a mixture of 64.5% Gyeongju clay, 15.0% kaolin, 15.0% FNS(Ferro Nickel Slag), and 5.5% MAS(Magnesia Aluminum Silicate) under optimal conditions. The results of the experiment involving firing at 1,125℃ showed that flexural strength of 12,102N, which is higher than the standard of KS F 3510, an absorption rate of 6.08%, a volume specific gravity of 2.15g/cm³, and the freeze-thaw properties were satisfied. A method for securing stable quality was studied.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.12
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• pp.357-362
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• 2023

Bridges are important transportation infrastructure, but they are subject to damage and cracking due to various environmental factors and constant traffic loads, which accelerate their aging. With many bridges now older than their original construction, there is a need for systems to ensure safety and diagnose deterioration. Bridges are already utilizing structural health monitoring (SHM) technology to monitor the condition of bridges in real time or periodically. Along with this technology, the development of intelligent bridge monitoring technology utilizing artificial intelligence and Internet of Things technology is underway. In this paper, we study an edge system technique for predicting bridge safety using fast Fourier transform and dimensionality reduction algorithm for maintenance of aging bridges. In particular, unlike previous studies, we investigate whether it is possible to form a dataset using sensor data collected from actual bridges and check the safety of bridges.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.2
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• pp.324-334
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• 2017

The simulators for a plant unit master control (UMC) developed by domestic or overseas researchers have been developed for operator-training purposes. UMC simulators normally constructed at the end of the plant construction, despite the UMC logics, should be simulated to pre-check many signal interfaces within the power generation systems. Because of the differences in construction schedule, it is difficult for logic designers or commissioning engineers to simulate the UMC logic during the design or commissioning stage. In this background, this paper proposes a simulation method that can be used easily by plant logic designers or operators in the MATLAB Simulink programming environment. The core of the UMC is realized with a unique simulation algorithm based on mathematical analysis and functional blocks combination. In addition, an integer-based configuration was proposed to realize the plant target value control for the equipment in the logic. With these simulation methods, functions, e.g., load distribution, high-low limitations, frequency compensation, etc. were simulated. The results showed that the plant UMC logic can be simulated in Simulink without a plant simulator. The various functions proposed in this paper can provide useful information about Simulink-based simulation design for plant logic designers or commissioning engineers during the power plant construction period.