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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>
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.
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.
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.
초고층 주거용 주상복합 건축물의 공종별 하자발생 특성 분석 연구
이웅균(Lee Ung-Kyun),서장우(Seo Jang-Woo),강경인(Kang Kyung-In) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.9
In spite of the recent rapid increase in high-rise residential building, minimal research has been carried out that focuses on the consequences of such a rapid increase, such as the occurrence of defects. The aim of this paper is to provide basic information on the pattern and character of defects of high-rise residential buildings based on historical data. In order to determine the occurring frequency characteristics of work types of high-rise residential building defects, a logistic regression analysis is conducted. The order of frequency ranking is wood floor finishing material, tiling, marble finishing, built-in furniture, kitchen furniture, wallpapering, ceiling finish, wood door/window work, and aluminum window work. For analysis, the dependent variable is set for the case where a work-type defect occurs between two high ranked ones. The independent variables are set for an elapsed year from the time of building completion (usage year), including structure type, the floor area of each household, and the location of where the defect occurred. The results show that structure type affects the occurrence of built-in furniture defects and the locations of the area of the defect affects whole work-types, but floor level defects do not occur in all cases. Furthermore, the wood door/window work does not decrease with time, though other work-types decrease. This result showed that the wood door/window work needs to be managed by life-cycle management.
유전자 알고리즘 모델을 활용한 양중계획 합리화 방안 - 타워크레인을 중심으로 -
이웅균(Lee Ung-Kyun),김재엽(Kim Jae-Youp),서덕석(Seo Deok-Seok),강경인(Kang Kyung-In) 대한건축학회 2004 大韓建築學會論文集 : 構造系 Vol.20 No.2
The selection of the tower crane with the stock yard requires an organized study due to a large tendency of relying upon experience and intuition. Therefore, this paper proposes a prototype model using the genetic algorithm, the most used method lately. The transportation distance is considered as the key factor in location selection of the tower crane, applying the relationship between the length of the tower crane boom and the main gate as the constrain factor. Genetic algorithm was used to select a location of the tower crane in relation with the stock yard, and case-studied. In this case, stock yard was located the same, whereas that of the tower crane resulted in 7m difference due to constructability. Development of more advanced model and establishment of system should be made allowing more systematical construction management.