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납기와 작업준비비용을 고려한 병렬기계에서 딥러닝 기반의 일정계획 생성 모델
유우식,서주혁,이동훈,김다희,김관호 한국전자거래학회 2019 한국전자거래학회지 Vol.24 No.3
As the 4th industrial revolution progressing, manufacturers are trying to apply intelligent information technologies such as IoT(internet of things) and machine learning. In the semiconductor/LCD/tire manufacturing process, schedule plan that minimizes setup change and due date violation is very important in order to ensure efficient production. Therefore,in this paper, we suggest the deep learning based scheduling generation model minimizes setup change and due date violation in parallel machines. The proposed model learns patternsof minimizing setup change and due date violation depending on considered order using the amount of historical data. Therefore, the experiment results using three dataset dependingon levels of the order list, the proposed model outperforms compared to priority rules. 4차 산업혁명이 진행되면서 제조업에서 사물인터넷(IoT), 머신러닝과 같은 지능정보기술을 적용하는 사례가 증가하고 있다. 반도체/LCD/타이어 제조공정에서는 납기일(due date)을 준수하면서 작업물 종류 변경(Job change)으로 인한 작업 준비 비용(Setup Cost)을 최소화 하는 일정계획을 수립하는 것이 효과적인 제품 생산을 위해 매우 중요하다. 따라서 본 연구에서는 병렬기계에서 딥러닝 기반의 납기 지연과 작업 준비 비용 최소화를 달성하는 일정계획 생성 모델을 제안한다. 제안한 모델은 과거의 많은 데이터를 이용하여 고려되어지는 주문에 대해 작업 준비와 납기 지연을 최소화하는 패턴을 학습한다. 따라서 세 가지 주문 리스트의 난이도에 따른 실험 결과, 본 연구에서 제안한 기법이 기존의 우선순위 규칙보다 성능이 우수하다는 것을 확인하였다.
김민환(M. H. Kim),김종인(J. I. Kim),박진석(J. S. Park) 한국전산유체공학회 2001 한국전산유체공학회지 Vol.6 No.1
The CFD analysis of the three-dimensional turbulent flow in the impeller and diffuser of an axial flow pump was performed, Not only the design point but also the off-design points were computed. The results were compared with available experimental data in terms of head generated. At the design point, the analysis accurately predicted the experimental head value. In the range of the higher flow rates, the results were also in very good agreement with the experimental data, not only in absolute value but also in term of slope. Although experimental data to be compared were not available in the range of the lower How rates, the results well described the S-shape performance curve of the axial pump characteristic.
김민환(M. H. Kim),이재선(J. S. Lee),박진석(J. S. Park),김종인(J. I. Kim),김긍구(K. K. Kim) 한국전산유체공학회 2003 한국전산유체공학회지 Vol.8 No.3
CFD analyses of the three-dimensional turbulent flow in the impeller and diffuser of an axial flow pump including suction and discharge parts are presented and compared with experimental data. The purpose of the current study is to validate the CFD method for the performance analysis of the main coolant pump for SMART and to investigate the effect of suction and discharge shapes on the pump performance. To generate a performance curve, not only the design point but also the off-design points were computed. The results were compared with available experimental data in terms of head generated. At the design point, the analysis accurately predicts the experimental head value. In the range of the higher flow rates, the results are also in very good agreement with the experimental data, in magnitude but also in terms of slope of variation. For lower flow rates, the results shows that the analysis considering the suction and discharge well describe the typical S-shape performance curve of the axial pump.
비정렬 격자계에서 고차 정확도 불연속 갤러킨-다차원 공간 제한 기법을 이용한 유동 물리 해석
박진석(J.S. Park),김종암(C. Kim) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
The present paper deals with the continuous works of extending the multi-dimensional limiting process (MLP) for compressible flows, which has been quite successful in finite volume methods, into discontinuous Galerkin (DG) methods. From the series of the previous, it was observed that the MLP shows several superior characteristics, such as an efficient controlling of multi-dimensional oscillations and accurate capturing of both discontinuous and continuous flow features. Mathematically, fundamental mechanism of oscillation-control in multiple dimensions has been established by satisfaction of the maximum principle. The MLP limiting strategy is extended into DG framework, which takes advantage of higher-order reconstruction within compact stencil, to capture detailed flow structures very accurately. At the present, it is observed that the proposed approach yields outstanding performances in resolving non-compressive as well as compressive flow features. In the presentation, further numerical analyses and results are going to be presented to validate that the newly developed DG-MLP methods provide quite desirable performances in controlling numerical oscillations as well as capturing key flow features.
박진석(J.S. Park),김종암(C. Kim) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
The present paper deals with the continuous work of extending multi-dimensional limiting process (MLP), which has been quite successfully proposed on two- and three-dimensional structured grids, onto the unstructured grids. The basic idea of the present limiting strategy is to control the distribution of both cell-centered and cell-vertex physical properties to mimic a multi-dimensional nature of flow physics, which can be formulated as so called the MLP condition. The MLP condition can guarantee a high-order spatial accuracy without yielding spurious oscillations. Recently, MLP slope limiter was proposed based on the MUSCL-type reconstruction in two-dimensional case and it can be readily extended to three-dimensional case. Through various numerical analyses and extensive computations, it is observed that the proposed limiters are quite effective in controlling numerical oscillations and very accurate in capturing both discontinuous and continuous multi-dimensional flow features on 3-D tetrahedral grids.
낭상 뇌동맥류 혈류유동에서 비뉴우토니안 유체 모델의 영향
박진석(J.-S. Park),이상욱(S.-W. Lee) 한국전산유체공학회 2011 한국전산유체공학회지 Vol.16 No.2
The importance of shear thinning non-Newtonian blood rheology on the hemodynamic characteristics of idealized cerebral saccular aneurysms were investigated by carrying out CFD simulations assuming two different non-Newtonian rheology models (Carreau and Ballyk models). To explore effects of vessel curvature, a straight and a curved vessel geometry were considered. The wall shear stress(WSS), relative residence time(RRT) and velocity distribution were compared at the different phases of cardiac cycle. As expected, blood entered the aneurysm at the distal neck and created large vortex in both aneurysms, but with higher momentum on the curved vessel. Hemodynamic characteristics such as WSS, and RRT exhibited only minor effects by choice of different rheological models although Ballyk model produced relatively higher effects. We conclude that the assumption of Newtonian fluid is reasonable for studies aimed at quantifying the hemodynamic characteristics, in particular, WSS-based parameters, considering the current accuracy level of medical image of cerebral aneurysm.