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공정간 시간 제약을 가지는 Wafer Lot의 대기 시간 예측
이기한(Gi Han Lee),천상욱(Sang uk Cheon),박상철(Sang Chul Park) (사)한국CDE학회 2020 한국CDE학회 논문집 Vol.25 No.4
This paper proposes a machine learning based method to predict the ‘queue-time’ of a target lot with time-constraints among processing steps. Since time-constraints among processing steps exist for quality assurance, it is very important to meet the time-constraints in Fab operations. To do so, we need to have an accurate prediction model for the ‘queue-time’ of a target lot. This paper identifies two categories of predictor variables; 1) work-in-process related variables, and 2) dispatching rule related variables. Since the quality of the prediction model depends on the quality of predictor variables, we need to carefully select predictor variables by considering their explanatory powers and multi-collinearities among them. In this paper, we employ the genetic algorithm for the section of best predictor variables. The prediction model is a fully-connected deep learning model, and the demonstration shows the performance of the model.
제어시뮬레이션을 위한 생산시스템 로그데이터 기반 플랜트 모델 생성 방법
고민석(Minsuk Ko),천상욱(Sang Uk Cheon),박상철(Sang Chul Park) (사)한국CDE학회 2013 한국CDE학회 논문집 Vol.18 No.1
Presented in the paper is a log data based modeling method for effective construction of a virtual plant model which can be used for the virtual PLC (Programmable Logic Controller) simulation. For the PLC simulation, the corresponding virtual plant, consisting of virtual devices, is required to interact with the input and output symbols of a PLC. In other words, the behavior of a virtual device should be the same as that of the real device. Conventionally, the DEVS (Discrete Event Systems Specifications) formalism has been used to represent the behavior a virtual device. The modeling using DEVS formalism, however, requires in-depth knowledge in the simulation area, as well as the significant amount of time and efforts. One of the key ideas of the proposed method is to generate a plant model based on the log data obtained from the production system. The proposed method is very intuitive, and it can be used to generate the full behavior model of a virtual device. The proposed approach was applied to an AGV (Automated Guided Vehicle).
ISO 10303 STEP 을 지원하는 절차적 2D CAD 데이터 번역기 개발
김병철(Byung Chul Kim),천상욱(Sang-Uk Cheon),문두환(Duhwan Mun) 대한기계학회 2013 大韓機械學會論文集A Vol.37 No.5
절차적 모델은 모델링 명령어의 매개변수 값을 변경하여 쉽게 수정을 할 수 있는 장점이 있다. 이전 연구sub{(1,2)}에서 저자들은 ISO 10303 국제 표준에서 절차적 2D CAD 모델을 표현하는 방법을 제안하고 절차적 2D CAD 모델 교환을 위한 ISO 10303-112 를 개발하였다. 이 논문에서는 ISO 10303-112 를 지원하는 절차적 2D CAD 데이터 번역기의 개발 방법을 제안한다. 그리고 번역기에 적용된 핵심 기술에 대해서 설명한다. 제안하는 방법의 유효성은 프로토타입 번역기를 사용한 데이터 교환 시험을 통해 검증하였다. Procedural models have the advantage of being easy to edit simply by changing the values of the parameters of their constructional operations. In previous studies,sub{(1,2)} we have introduced an approach for representing procedural 2D CAD models in ISO 10303 and developed ISO 10303-112 for the exchange of procedural 2D CAD models. In this paper, a method for the development of a procedural 2D CAD data translator supporting ISO 10303-112 is suggested. Furthermore, the core techniques applied to the translator are resented. The feasibility of the proposed method was demonstrated through data exchange experiments using a prototype translator.
공장 배치 계획에서 혼합현실의 적용을 위한 안전표지판 인식
이종환(Jonghwan Lee),한순흥(Soonhung Han),천상욱(Sang-Uk Cheon) (사)한국CDE학회 2009 한국CDE학회 논문집 Vol.14 No.1
Virtual manufacturing technology has been applied in actual production sites with the development of virtual reality technology. However, the current virtual manufacturing technology requires experts for application of the system. Furthermore, the sense of reality is diminished as the entire simulation is driven by virtual objects. In contrast, mixed reality can visualize virtual objects and an actual work place simultaneously, and thus the sense of reality of the virtual manufacturing simulation can be improved. This paper introduces a method that applies mixed reality in the manufacturing process, and proposes a method to adapt general safety sign post in the factory instead of a black square marker for visual fiducial recognition.