• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.569-574
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• 2008

Recently, the domestic remodeling market is increased in scale. This study is to develop the sanitary piping system which improves quality of life and facility performance when the aged public housing is remodeled. Above all, we found out three standard floor plans in bathrooms of the public housing. And then, the plan and section types of the sanitary piping system were developed for the on-floor piping, a construction cost of each section types was estimated to review the economical fact. Also, the field mock-up test was performed in the type of the pipe shaft with on-floor pit. In result, the developed sanitary piping system was available for the remodeling public housing without a great facility cost. Additionally, the sanitary pipe was replaced easily through the shaft and on-floor fit. And a noise was reduced to a lower unit when the water flowed down.

• Geomechanics and Engineering
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• 제17권2호
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• pp.133-143
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• 2019

An optimal hydraulic section is critical for irrigated water conservancy in seasonal frozen ground due to a large proportion of water leakage, as investigated by in-situ surveys. This is highly correlated with the frost heave of underlain soils in cold season. This paper firstly derived a practical model for frost heave of clayey soils, with temperature dependent thermal indexes incorporating phase change effect. A model test carried out on clay was used to verify the rationality of the model. A novel approach for optimizing the cross-section of irrigation canals in cold regions was suggested with live updated geometry characterized by three unique geometric constraints including slope of canal, ratio of practical flow section to the optimal and lining thickness. Allowable frost heave deformation and tensile stress in canal lining are utilized as standard in computation iterating with geometry updating while the construction cost per unit length is regarded as the eventual target in optimization. A typical section along the Jinghui irrigation canal was selected to be optimized with the above requirements satisfied. Results prove that the optimized hydraulic section exhibits smaller frost heave deformation, lower tensile stress and lower construction cost.

• 한국건설관리학회논문집
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• 제22권2호
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• pp.42-52
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• 2021

공동주택 주차장 리모델링 공사비는 전체 리모델링 공사비의 대략 20%를 차지한다. 지하주차장 공사비를 알면 전체 공사비 예측이 가능한 것이다. 공사비 산정 시 참고하는 표준품셈은 리모델링 공사비 산정에 적용하기 곤란하여 리모델링 공사의 특징을 반영할 수 있는 공사비 산정 모델이 필요하다. 이 연구에서는 리모델링의 특징 및 설계 요소를 반영하여 개략 공사비를 산정하는 공동주택 지하주차장 확대 리모델링의 개략 공사비 산정 모델을 개발하였다. 선행 연구 고찰 및 전문가 자문을 통해 지하주차장 리모델링 공사의 Activity를 37개 도출하였다. 리모델링 설계도면이 확정되기 전 개략 공사비를 산정할 수 있도록 Activity 별 물량 산출식 및 단가를 제시하였다. 전문가 자문을 통해 공사비 상승에 영향을 미치는 요인 13개와 요인 별 가중치를 결정하였다. 리모델링 사례단지 3개를 개략 공사비 산정 모델에 적용한 결과, 정확도는 평균 93%로 나타났다.

• 상하수도학회지
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• 제13권1호
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• pp.61-71
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• 1999

For a high-rate fermentation and recovery of organic acid, we have developed a new organic acid fermentation reactor with membrane filter, which is the most important part in the new advanced wastewater treatment system. The recovered organic acid is to be reused as an organic carbon source at denitrification process. Some experiments were conducted to compare the performance of acid fermentation at different SRTs, such as 5, 10, and 20 days. The total organic acid concentration produced during the runs was in the range of 2,100-2,900 (mgC/L). The conversion efficiency from substrate to organic acid reached to from 43% to 59%. The recovery rate of organic acid from substrate based on TOC was from 26% to 53%. Regardless of operational conditions, it has been able to maintain the membrane flux constantly, in the range of 0.4-0.46 ($m^3/m^2/day$). The transmembrane pressure drop was 0.2-0.3 (kg/cm) for 100 day's operation. The result of simulation is as follows. Organic removal efficiency of the new advanced treatment system is 95%. 73% of Nitrogen is removed. The removal efficiency of Phosphorus is 93%. By coqulation, soluble phosphorus is able to remove from the water treatment lines, which is impossible at conventional activated sludge system. The unit construction cost is 65000 (yen/m3) and it was 1.4 times than that of the standard activated sludge system. The unit operation cast is 7.7 ($yen/m^3/day$) and it was 1.3 times than that of the standard activated sludge system.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.975-979
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• 2008

Since tram has the advantages to reduce construction cost of infrastructure, to improve accessibility of passengers, and to offer visual pleasures, nowadays, it is one of light rails attracting public attention. Tram can be classified into two groups, one is a conventional steel-wheeled type, and the other is a rubber-tired type (bi-modal tram). The bi-modal tram propelled by the serial CNG hybrid propulsion unit has been developing since 2003 in Korea, which can realize both scheduled operation of railway and route flexibility of bus. Because the bimodal will be operated on both railway mode and bus mode, however, specific criteria and regulations for its design, certification, construction, operation and maintenance have not been determined definitely yet. In consideration of mobility enhancement for the old and the handicapped, motor vehicle safety standard and urban transit (railway vehicle) safety standard, several design specifications were proposed for car body and interiors of the bimodal tram vehicle. The design specifications proposed in this paper can be expected to promote passengers' comfort and safety, operation efficiency of the bimodal tram.

• 수산경영론집
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• 제46권2호
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• pp.59-74
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• 2015

This study aims to estimate optimal harvesting production, fishing efforts, and stock levels of yellow croaker caught by the offshore Stow Net and the offshore Gill Net fisheries using the current value Hamiltonian method and the surplus production model. As analyzing processes, firstly, this study uses the Gavaris general linear model to estimate standardized fishing efforts of yellow croaker caught by the above multiple fisheries. Secondly, this study applies the Clarke Yoshimoto Pooley(CY&P) model among the various exponential growth models to estimate intrinsic growth rate(r), environmental carrying capacity(K), and catchability coefficient(q) of yellow croaker which inhabits in offshore area of Korea. Thirdly, the study determines optimal harvesting production, fishing efforts, and stock levels of yellow croaker using the current value Hamiltonian method which is including average landing price of yellow croaker, average unit cost of fishing efforts, and social discount rate based on standard of the Korean Development Institute. Finally, this study tries sensitivity analysis to understand changes in optimal harvesting production, fishing efforts, and stock levels of yellow croaker caused by changes in economic and biological parameters. As results drawn by the current value Hamiltonian model, the optimal harvesting production, fishing efforts, and stock levels of yellow croaker caught by the multiple fisheries were estimated as 19,173 ton, 101,644 horse power, and 146,144 ton respectively. In addition, as results of sensitivity analysis, firstly, if the social discount rate and the average landing price of yellow croaker continuously increase, the optimal harvesting production of yellow croaker increases at decreasing rate and then finally slightly decreases due to decreases in stock levels of yellow croaker. Secondly, if the average unit cost of fishing efforts continuously increases, the optimal fishing efforts of the multiple fisheries decreases, but the optimal stock level of yellow croaker increases. The optimal harvest starts climbing and then continuously decreases due to increases in the average unit cost. Thirdly, when the intrinsic growth rate of yellow croaker increases, the optimal harvest, fishing efforts, and stock level all continuously increase. In conclusion, this study suggests that the optimal harvesting production and fishing efforts were much less than actual harvesting production(35,279 ton) and estimated standardized fishing efforts(175,512 horse power) in 2013. This result implies that yellow croaker has been overfished due to excessive fishing efforts. Efficient management and conservative policy on stock of yellow croaker need to be urgently implemented.

• 한국물환경학회지
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• 제22권5호
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• pp.905-912
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• 2006

In this paper, simulation methods of the system dynamics model developed by Das et al. (1997) for activated-sludge wastewater treatment plants are illustrated in an attempt to determine the operating rules and the policies related to capacity expansion of an activated-sludge wastewater treatment plant. For existing conditions, the analyses were performed by varying activated-sludge return rate to observe changes in effluent water quality and treatment efficiency. The effluent water quality is also analyzed for various average daily inflow conditions and activated-sludge return rates. As a result, without expanding the aeration tank, maximum average daily inflow that can satisfy the effluent water quality standard of BOD $0.02kg/m^3$ was determined as $2,840m^3/hr$, subject to 100% of activated-sludge return rate while other factors remain constant. When the activated-sludge return rate is less than 100%, expansion of the aeration tank is necessary and minimum sizes of the aeration tank to satisfy the effluent water quality standard were determined for various activated-sludge return rates. In addition, the total operating and maintenance as well as unit treatment cost regression equations for activated-sludge wastewater treatment plants are suggested by using the cost data that are obtained from Water and Wastewater Division, Ministry of Environment. The regression analyses showed that the economies of scale phenomena exist in the operating and maintenance costs of activated-sludge wastewater treatment plants.

• 대한건축학회논문집:구조계
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• 제36권1호
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• pp.173-178
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• 2020

In this study, we analyzed space heating and domestic hot water(DHW) charges from 2017 to 2018 for 151,206 households in 202 apartment complexes built from 1997 to 2016, in order to evaluate the effectiveness of Korea's insulation standards reinforcement. The applied insulation standards were revised three times(in 1987, 2001 and 2010). We used the Anderson-Darling test to review the normality of the space heating and DHW charges. As a result, each p-value was greater than 0.05 and it followed the normal distribution. The annual average space heating charges per unit area of apartments with the 1987 insulation standards were 5,237￦/㎡a in 2017 and 5,328￦/㎡a in 2018. The heating charges with the 2001 standards were 4,827￦/㎡a in 2017 and 4,817￦/㎡a in 2018. Compared to previous standards(1987 standards), heating charges decreased by 7.8% and 9.6%. Also the heating charges with the 2010 standards were 3,683￦/㎡a in 2017 and 3,734￦/㎡a in 2018. Compared to previous standards(2001 standards), heating charges decreased by 24.3% and 21.5%. On the other hand, compared to each previous standards, DHW charges were decreased by 12.2%, 13.6% or increased by 4.6%, 6.9%, which means there's no correlation between insulation standards reinforcement and DHW charges.

• 대한토목학회논문집
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• 제28권1D호
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• pp.67-72
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• 2008

건설기계는 건설사업의 성공적인 수행을 위한 중요한 요인이다. 그리고 건설기계에 소요되는 비용이 건설공사비에서 차지하는 비중이 크다. 따라서 건설기계 비용의 산정은 건설계획 단계에서 중요한 업무이다. 이를 위해서 우리나라는 표준 품셈에 제시된 건설기계 시공능력 산정식을 이용하여 건설기계의 시간당 작업량을 계산하는 방식을 활용하고 있다. 그러나 건설기계의 성능은 개선되고 있으나 시공능력 산정식에서 활용되고 있는 작업효율은 이를 반영하지 못하는 실정이다. 이에 본 연구는 유압식 백호, 로우더, 덤프트럭을 대상으로 현장실사를 통해 작업효율을 실측하였다. 그 결과 백호와 로우더는 현재 활용중인 작업효율보다 현장실사 값이 높게 나타났으며, 덤프트럭은 낮게 나타났다. 본 연구결과를 바탕으로 건설기계의 작업효율 표준 산정식에 대한 정의가 수립되어야 하며, 체계적이고 장기적인 조사를 거쳐 작업효율의 개정이 필요할 것으로 사료된다.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회/대한산업공학회 2005년도 춘계공동학술대회 발표논문
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• pp.80-83
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• 2005

The competitiveness of the manufacturing company is evaluated in terms of line productivity, quality cost, inventory level, logistics efficiency, and so on. The productivity is defined by the number of products divided by the number of workers within the given operation time. Increasing the productivity is not easy to man-operated situation in the line, since it heavily depends on the standard time of the workers. This paper deals with the productivity of the Back Light Unit assembler for TFT-LCD, and proposes the methodology of investigating the optimal process by simulation of Arena.