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김대철,이근호,김형의,Kim, Dae-Cheol,Lee, Geun-Ho,Kim, Hyeong-Ui 한국기계연구원 2002 硏究論文集 Vol.32 No.-
This study was performed to develop accelerated life test method of machanical parts using cumulative damage theory that used to model the fatigue of parts that receive variable load. The cumulative damage theory was introduced, and the estimation of life and calculation of accelerated life test time was illustrated. As the actual application example, accelerated life test method of agricultural tractor transmission was described. Life distribution of agricultural tractor transmission was supposed to follow Weibull distribution and life test time was calculated under the conditions of average life (MTBF) 3,000 hours and 90% reliability for one test sample. According to the cumulative damage theory, because test time can shorten in case increase test load, test time could be reduced by 482 hours when we put the load 1.1 times of rated load than 0.73 times of rated load that is equivalent load calculated by load spectrum of the agricultural tractor. This time, acceleration coefficient was 11.7. This accelerated test method was used to develop accelerated test method of gear reducer, hydraulic hose and bearing as well as agricultural tractor transmission and it is considered to be applied comprehensively to machanical parts the fatigue of which is happened by load or pressure etc.
A Lagrangian Relaxation Method for Parallel Machine Scheduling with Resource Constraints
김대철,Kim, Dae-Cheol Korean Institute of Industrial Engineers 1998 산업공학 Vol.11 No.3
This research considers the problem of scheduling jobs on parallel machines with non-common due dates and additional resource constraints. The objective is to minimize the total absolute deviation of job completion times about the due dates. Job processing times are assumed to be the same. This problem is motivated by restrictions that occur in the handling and processing of jobs in certain phases of semiconductor manufacturing and other production systems. We examine two problems. For the first of these, the number of different types of additional: resources and resource requirements per job are arbitrary. The problem is formulated as a zero-one integer linear programming and the Lagrangian relaxation approach is used. For the second case, there exists one single type of additional resource and the resource requirements per job are zero or one. We show how to formulate the problem as an assignment problem.
병렬기계로 구성된 인쇄회로기판 제조공정에서의 스케쥴링에 관한 연구
김대철(Dae-Cheol Kim) 한국산업경영시스템학회 2004 한국산업경영시스템학회지 Vol.27 No.4
This research considers the problem of scheduling Jobs on unrelated parallel machines with a common due date The objective is to minimize the total absolute deviation of Job completion times about the common due date. This problem is motivated by the fact that a certain phase of printed Circuit board manufacturing and other production systems is bottle-neck and the processing speeds of parallel machines in this phase are different for each Job. A zero-one integer program-ming formulation is presented and two dominance properties are proved. By these dominance properties, It is shown that the problem is reduced to asymmetric assignment problem and is solvable in polynomial time
김대철(Dae Cheol Kim),김재범(Jae Bum Kim),조근태(Keun Tae Cho) 한국경영과학회 2013 經營 科學 Vol.30 No.2
The objective of this paper is to provide an improved technology appraisal model, which considers a variety of macroeconomic variables such as consumer price index and producer price index. The improved model was built using cross correlation analysis and logistic regression analysis. The AUROC analysis showed that goodness-of-fit of the proposed model turned out to be improved than that of the existing model. The model proposed in the paper would be helpful for making a reasonable investments and financing decision, lessening the default rates by systematic risk management, and enhancing the technology commercialization capabilities.
김대철 ( Dae Cheol Kim ),주형준 ( Hyung Jun Ju ),김승철 ( Seung Chui Kim ) 한국생산성학회 2015 生産性論集 Vol.29 No.3
This study analyzes the efficiency and performance of software growth supporting projects conducted in 18 regions by utilizing data envelopment analysis(DEA). In addition, relationships among the satisfaction of firms performed the projects toward the regional software growth supporting centers, revenue increases, number of new employees, and the efficiencies of projects of 18 regions are studied with the size of revenue as a moderating variable. The effects of a competition environment on the efficiencies of the projects, the rates of revenue growth rate, and number of newly hired employees are also addressed. For the study, input based DEA models are used to reflect the characteristics of public sector. To analyze the DEA models, we used data which were collected by the Korea Regional SW Industry Promotion Council in 2013 and the results of the Regional SW Growth Supporting Projects performed at the 18 regions in 2012. From the CCR DEA model, we found that only the projects performed at Youngin is shown to be efficient. The overall efficiency of 18 regions’ projects is as low as 35%. The result of the BCC DEA model addresses that the projects conducted at four regions(Gangwon, Anyang, Yongin, Jeju) are efficient. The average efficiency of projects of 18 regions are about 72.5%. From the scale efficiency perspective, projects of Youngin are found to be the most efficient and Taegu’s is the worst. In particular, Taugu’s inefficiency results from the technical inefficiency. Furthermore, the higher the efficiency of the projects is, the larger the degree of the satisfaction towards agencies, the speed of revenue increasement, and the number of newly hired employees are in accordance with the size of revenue. It is also found that the more competitive environment there is, the higher efficiencies the regional software growth supporting projects result in. However, severe competition among SW/IT companies decreases the rate of revenue increasement and the number of newly hired employees.
소성가공 분야에서 인공지능을 이용한 절단면 이물질 검출
김대철(Dae-Cheol Kim),박정민(Jeong-Min Park),이수민(Su-Min Lee),홍인희(In-Hee Hong),김성규(Seong-Kyu Kim),이원곡(Won-Gok Lee),배유석(You-Seok Bae) 한국정보기술학회 2022 한국정보기술학회논문지 Vol.20 No.2
The aging operation method of the root industry (plastic processing industry) causes problems such as aging of professional personnel, difficulty in transferring know-how at production sites, decreasing productivity of unskilled workers, inaccuracy and quality of visual inspection-based systems. In line with the fourth industrial revolution, it is a trend to solve the above root industry problems by establishing a smart factory applying artificial intelligence technology. In this paper, cutting surfaces foreign material detection techniques are implemented through artificial intelligence object detection to reduce the occurrence of defects in forging processes in the plastic processing field. In addition, acurancy and mean Average Precision (mAP) were compared with the detection results of Fast-RCNN, SSD, and Yolo to prove the possibility of establishing a smart factory optimized for the plastic processing industry.