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단위작업 물량 달성율과 투입 노무량을 이용한 진도율 산정방법에 관한 연구 - 공동주택공사의 골조공사를 중심으로 -
최현하,이준복,Choi Hyun-Ha,Lee Junbok 한국건설관리학회 2005 건설관리 : 한국건설관리학회 학회지 Vol.6 No.1
건설공사에서 공정관리는 중요하다. 특히 공동주택의 경우 입주일이라는 절대공기의 준수가 매우 중요하다. 이와 같은 공정관리를 위해 공동주택공사에서는 공종별 진도관리가 필요하며, 이는 진도율 산정을 통하여 일정계산 및 기성 산정의 척도로서 사용되고 있다. 현재 국내의 공동주택 건설현장에서 사용되고 있는 대부분의 진도율 산정방식은 경험과 개략적인 수치에 의한 판단에 의존하는 경우가 많아공정의 계획과 공정의 지연시 합리적 만회 대책의 수립이 어려움등 한계를 보이고 있다. 이와 같은 문제를 해결하기 위하여 본 연구에서는 단위작업에서의 물량 달성율과 투입 노무량을 이용한 진도율 산정방식을 제시하고 있다. 즉, 단위작업 진도율은 단위작업에서 수집된 투입 노무량을 층단위의 전체 투입노무량 중의 가중치로 환산하고 이를 물량달성도($\%$)와 곱하여 산출된다. 같은 방법으로 본 연구에서 제시하고 있는 작업분류체계의 상위단계인 층 진도율, 동 진도율을 산출하게 된다 공동주택공사의 골조공사를 대상으로 단위작업, 층, 동 진도율 산정방법을 예시로서 제시하고 있다. 이와 같은 진도율은 향후 단위작업의 노무생산성과 달성물량에 대한 실적데이터의 축적이 이루어질 경우 보다 합리적이고 과학적인 공정관리의 근간이 될 것으로 기대된다. Time management is important in construction management Especially, in the high-rise apartment housing projects, it is very important to expedite the construction progress in order to meet the planned schedule. The objective of this paper is to propose the baseline for the progress rate using work volume and man $\cdot$ hours performed at work activity level. The work volume far each activity is transformed to the weighted value compared to total work volume for the floor Therefore, a progress rate for an activity is calculated by multiplying a weighted value and work volume. A progress rate for a floor and a building can calculated in this manner, respectively.
DOC 장착시 전기히터/촉매 복합 재생방식 매연여과장치의 성능향상에 관한 연구
최현하(Hyunha Choi),김홍석(Hongsuk Kim),정용일(Youngil Jeong),임인혁(In-hyuk Im),황재원(Jae-Won Hwang) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
H-CDPF system regenerates the ceramic monolith filter both actively by an electrical heater and passively by a CDPF. The aim of this study is to compare the performance of the DOC coupled H-CDPF system with the DOC uncoupled H-CDPF system. In this study, the H-CDPF system was installed on the midium duty diesel engine of which already meets EURO-2 standards. The BPT of the DOC coupled H-CDPF system was about 40℃ lower than that of DOC uncoupled H-CDPF system. The DOC coupled H-CDPF system enhanced the active regeneration by the electrical heater at an idle engine condition. Also in the durability test which simulated actual city driving conditions, the DOC coupled H-CDPF system showed better regeneration characteristics.
Urea-SCR 촉매가 코팅되는 전기히터 시스템의 NOx저감 성능에 관한 연구
최현하(Huunha Choi),김홍석(Hongsuk Kim),정용일(Yongil Jeong),임인혁(In-hyuk Im),박정한(Jeonghan Park),황재원(Jae-Won Hwang) 한국자동차공학회 2007 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
It is well known that a urea-SCR system can reduce NOx emissions of a diesel engine effectively. But the urea-SCR technology does not shows a good NOx reduction performance at low temperature exhaust gas conditions. This study introduces a newly developed urea-SCR catalyst coated electrical heater system. This system can reduce NOx emissions of a diesel engine effectively even though at low temperature exhaust gas conditions by increasing the surface temperature of SCR catalyst electrically. The study compares the NOx reduction performance of the newly developed urea-SCR system with a conventional system. This study shows that the new urea-SCR system has high performance and low NH₃ slip at the low temperature exhaust gas conditions.
SiC 필터를 사용하는 3L급 승용 디젤엔진용 DPF에서 배압을 이용한 매연포집량 예측에 대한 연구
최현하(Hyunha Choi),김홍석(Hongsuk Kim),안석종(Seokjong An),조규백(Gyubaek Cho),이진욱(Jinwook Lee),정용일(Youngil Jeong) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
It is important to know the accurate soot mass in a DPF to control when to start regeneration. The soot mass in a filter can be estimated by pressure drop of the filter and exhaust gas flow rates. In this study, a soot index is defined as a pressure drop of DPF devided by a pressure drop of DOC. This study suggests an effective signal processing method for the soot index and shows good correlation between the soot index and soot loading amount in the filter at both steady and transient engine operating conditions. This study uses a 3L diesel engine for passenger car.
李準馥,최현하 홍익대학교 산업기술연구소 2003 産業技術 Vol.13 No.-
The defects of a building bother both the residents and the builders. Defect information consists of information which is transmitted from the construction phase to the maintenance phase, and information which is occurred during building maintenance period. This study proposes the concept of an community dwelling defect information management system in order to manage the defect problems of the community dwelling houses efficiently, and furthermore to reduce the defect problems. This study focuses on Preliminary checking by residents prior to moving in a house.
촉매연소기를 이용한 소형 경유 운행차용 매연여과장치의 강제 재생 특성
김홍석(Hongsuk Kim),최현하(Hyunha Choi),조규백(Gyubaek Cho),정용일(Youngil Jeong),조성호(Sung-ho Cho),박종수(Jong-soo Park) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Light duty diesel vehicles are considered as one of major sources of particulate emissions in many cities, and the start of the retrofit program for the vehicles is expected in near future in Korea. One of the problems of the retrofit of the light duty diesel vehicles is that the exhaust gas temperature is too low to apply passive regeneration type DPF systems. This study introduces a new DPF regeneration technology using a catalytic combustor. This study shows the principle and characteristics of DPF regeneration by the catalytic combustor and suggests it's proper control method for better regeneration.
금속 폼 필터의 촉매 코팅에 따른 PM 저감 성능에 관한 연구
안석종(Seokjong An),조규백(Gyubaek Cho),최현하(Hyunha Choi),정용일(Youngil Jeong),이의성(Euisung Lee),오권오(Kwonoh Oh),한승한(Seunghan Han),김경재(Kyungjae Kim),박승룡(Seunglyong Park) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
The air in cities has been heavily polluted by vehicle emissions. Above all, exhaust gases of diesel engines is the principal cause of these air pollutions. DOC is used to reduce harmful emissions, such as HC, CO and PM. But PM reduction rate of DOC is not enough. DPF is necessary to reduce PM and satisfy regulations. Metal foam is the one of promising materials in process on researches. Metal foam filter is available to use with catalytic coating. In case of catalytic metal foam, it reduce efficiency of PM reduction. In this study, we research the cause why efficiency of PM reduction is been worse and find out the most suitable condition.
Urea-SCR 후처리장치의 NO<SUB>x</SUB> 저감에 대한 해석적 연구
윤병규(Byoungkyu Yun),김종민(Chongmin Kim),김종훈(Jong Hun Kim),김만영(Man Young Kim),최현하(Hyunha Choi),조규백(Gyubaek Cho),김홍석(Hongsuk Kim),정용일(Youngil Jeong) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
During the past few years emission regulations have become more stringent as a result of increased environmental issue and energy saving. To meet stringent emission regulations, an diesel exhaust gas after-treatment system was developed such as DOC, DPF, and SCR. Various reduction devices of NOx in exhaust gas existed, such as LNT (Lean NOx Trap), HC-SCR and Urea-SCR. Especially, it is well known that the Urea-SCR system for diesel engine after-treatment is very effective device for reduction of NOx in exhaust gas among others. However, the Urea-SCR has disadvantage of low NOx reduction efficiency, especially in low temperature exhaust gas condition. Furthermore, this device have many issues associated with the Ammonia slip phenomenon, layout optimization for NOx reduction, etc. This study presents an optimized property of Urea-SCR system for NOx reduction by changing such various parameters as space velocity and length of the DOC with the numerical experiments.