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Lee, Ung-Kyun The Korean Institute of Building Construction 2015 한국건축시공학회지 Vol.15 No.3
A large-scale research project to develop a robot-based automated building construction system for steel structures was successfully conducted in South Korea. This paper discusses the results of the real-scale test and the key lessons gained from the testing process. The system was assessed in terms of system productivity, construction cost, quality control, and safety improvements. While the productivity of the automated system showed an improvement of about 9.5%, the construction cost was about six times higher than that of the conventional method. The field test also indicated that the automated system requires more on-site quality control measures. However, because the system can eliminate the causes of various safety accidents, safety levels might be expected to be improved significantly. It is expected that this paper will provide knowledge and insight for developing new systems, and the results of the real-scale test might be useful for other researchers and similar research projects in the future.
Decision Support Tool for Excavation Operation using Genetic Algorithms
Ung-Kyun Lee,Kyung-In Kang,Hun-Hee Cho 대한건축학회 2006 Architectural research Vol.8 No.2
The appropriate fleet estimation of the excavation equipment is a major factor in the determination of the cost and time requirements of a project. But the decision of what kind of equipment selected is often based on heuristic methods or trial and error in Korea. Thus, this study proposes a prototype model that uses genetic algorithms to select fleet estimation of loaders (backhoe) and trucks used in excavation work. To verify the applicability of this model, the case study was performed. And the result of the genetic model was compared with that of the trial & error method. The use of the genetic model suggested this study required 44days, 2 units of backhoes, 7 units of trucks, and a total cost of 171,839,756 won. With the estimated fleet number of equipment, the minimum cost of excavation work can be calculated, taking account of the time-cost trade-off. By utilizing this prototype model, the efficiency of excavation work can be improved.
Development of a total variation noise reduction algorithm for chest digital tomosynthesis
Lee, In-Hyung,Kang, Dae-Ung,Shin, Sung-Wook,Lee, Ryun-Gyeong,Park, Jung-Kyun,Lee, Youngjin Elsevier 2019 Optik Vol.176 No.-
<P><B>Abstract</B></P> <P>Chest digital tomosynthesis (CDT) is developed to solve the problem of overlapping and absence of depth information as seen in general X-rays applied in chest radiography and high-exposure dose problem of computed tomography. However, in CDT, noise can reduce the quality of the image and increase the rate of false diagnosis. Thus, noise removal is an important issue in the clinical application of CDT, and a total variation (TV)-based noise reduction algorithm is an excellent algorithm because of its high noise reduction efficiency. In this study, we demonstrate the superiority of the TV noise reduction algorithm by quantitative comparisons of analyses with conventional algorithms. The quantitative evaluation of the image quality, coefficient of variation (COV), contrast-to-noise ratio (CNR), and intensity profile are evaluated. The COV and CNR results in the TV noise reduction algorithm are 1.88 times lower and 1.54 times higher than those of the original image, respectively; the smoothest graph is also obtained in the intensity profile. In conclusion, it is expected that the quality of the CDT image processed using the TV noise reduction algorithm is better than that processed using conventional noise reduction methods and the use of our algorithm will increase in the clinical field in the future.</P>
Assessment of Requirements for Successful Mobile Project Management Information Systems
Lee, Ung-Kyun,Jeong, Hyung Seok David,Woldesenbet, Asregedew The Korean Institute of Building Construction 2014 한국건축시공학회지 Vol.14 No.1
The objective of this study is to assess the requirements of tablet PC-based PMIS applications designed for use on construction sites to determine whether these new programs can play a significant role in increasing the efficiency of a project. In this research, the current market conditions of PMIS running on a tablet PC were analyzed. In addition, two industry surveys were conducted. A research team interviewed some industry experts and identified fourteen useful and desirable functions that can be incorporated into tablet PC-based applications and project management tools. Through a questionnaire survey, the most effective functions for the tablet PC-based PMIS were identified. The three top-rated functions among those suggested were Contact Information for Job-Related Personnel; Receive and Respond to Submittals, RFIs, and Notices; and Problem Solving for Design and Engineering Issues. The results of this research are expected to provide helpful information for mobile application developers and members of other interested groups in the construction industry.
Decision Support Tool for Excavation Operation using Genetic Algorithms
Lee, Ung-Kyun,Kang, Kyung-In,Cho, Hun-Hee Architectural Institute of Korea 2006 Architectural research Vol.8 No.2
The appropriate fleet estimation of the excavation equipment is a major factor in the determination of the cost and time requirements of a project. But the decision of what kind of equipment selected is often based on heuristic methods or trial and error in Korea. Thus, this study proposes a prototype model that uses genetic algorithms to select fleet estimation of loaders (backhoe) and trucks used in excavation work. To verify the applicability of this model, the case study was performed. And the result of the genetic model was compared with that of the trial & error method. The use of the genetic model suggested this study required 44days, 2 units of backhoes, 7 units of trucks, and a total cost of 171,839,756 won. With the estimated fleet number of equipment, the minimum cost of excavation work can be calculated, taking account of the time-cost trade-off. By utilizing this prototype model, the efficiency of excavation work can be improved.
Performance assessment model for robot-based automated construction systems
Lee, Ung-Kyun,Yoo, Wi Sung,An, Sung-Hoon,Doh, Nakju,Cho, Hunhee,Jun, Changhyun,Kim, Taehoon,Lee, Young Hoon The Korean Institute of Building Construction 2013 한국건축시공학회지 Vol.13 No.4
An adjusted assessment model based on benefit-cost analysis (BCA) is proposed for evaluating the economic efficiency of automated construction technologies. In contrast to conventional BCA, the model does not compare monetary values, but the differences in benefits and costs between traditional and automated construction methods. To verify the usefulness of the model, it was applied to a real-scale building construction project that used a fully automated building construction system, and the face validity of the model was confirmed. The results indicate that the model can support decision makers in identifying valuable benefit factors and in assessing the cost effectiveness of the system.
고층 건축물 마감공사를 위한 건설용 리프트 계획 및 관리 통합형 양중모델
이명도(Lee, Myung-Do),원명균(Won, Myeong-Kyun),이웅균(Lee, Ung-Kyun),조훈희(Cho, Hun-Hee),강경인(Kang, Kyung-In) 대한건축학회 2014 大韓建築學會論文集 : 構造系 Vol.30 No.5
The objective of this study is to propose an integrated lifting model of planning and operation for finishing works in tall building construction. The model consists of five components: lifting schedule chart, lifting load leveling, lifting equipment planning, lifting TACT and lifting table. The model was designed to provide a more practical lifting planning and operating method for construction managers as well as to cope with unexpected schedule delays. To validate the proposed model, a case study was performed in building a construction project; questionnaires were distributed in order to evaluate its effectiveness compared with the original method. A case study showed the following results. (1) The model is estimated to provide more practical lifting planning alternatives compared with the original method to construction managers. (2) The model can be a valuable management tool in terms of the lifting operation of construction lift. (3) The model can be provide an effective method to cope with unexpected situations through the integration of lifting planning and operation. Therefore, It is expected that the proposed model can be employed as practical means to the planning and operation of construction lift at construction sites.
이명도 ( Lee Myung-do ),이찬우 ( Lee Chan-woo ),임현수 ( Lim Hyun-su ),김태훈 ( Kim Tae-hoon ),이웅균 ( Lee Ung-kyun ) 한국건축시공학회 2019 한국건축시공학회 학술발표대회 논문집 Vol.19 No.1
Building Information Modeling (BIM) and modular construction are regarded as important technologies that address several issues faced by the construction industry. However, the application guidelines for BIM in current modular construction projects are insufficient. This paper presents the preliminary work on the analysis of BIM utilization in a modular construction project; a five-point likert scale questionnaire was conducted to assess the necessity of BIM applications by the Necessity Index(NI) of nine categories(U1~U9) across two construction phases (onsite and offsite). The survey results indicate that applications for BIM based quantity takeoff for offsite phase(U4) as well as BIM modeling for module joint details(U8) were deemed to be the most necessary in each phase. The results of this study can be used as detailed guidelines for the integration of BIM in modular construction projects.