DAS-ERECT

학위논문(박사) - 한국과학기술원 : 경영과학과, 1993.8, [ ix, 118 p. ]This research develops the erection scheduling expert system for shipbuilding: DAS-ERECT. The backbone scheduling in shipbuilding plant is the erection scheduling at the main docks, because the erection schedule influences on not only the makespan at the docks, but also the utilization level of overall shipbuilding plant including preceding block assembly shops. Thus the shipbuilding scheduling system requires a multi-level hierarchical architecture by nature. So our project, DAS project, has adopted the hierarchical architecture in building the scheduling expert systems for Daewoo shipbuilding company. In the hierarchical architecture, detailed scheduling necessary at the lower level assembly plants are delegated to the individual plant``s schedulers as far as the requirements from the higher level scheduler are satisfied. However, if the lower level scheduling is impossible, the higher level scheduler attempts to adjust the original requirements. The advantages of hierarchical architecture are the reduced computational complexity and its robustness during the reactive phase. The second key issue in scheduling at the docks stems from the complexity of search. To handle this problem, we propose the constraint dir ected graph search (CDGS) which amalgamates the notion of graph expansion and constraint directed pruning into an algorithm. The CDGS is guided by constraints not only for pruning search space but also for selecting the best node for erection. In this research, the algorithm for CDGS and the representation scheme for constraints are developed to realize the system DAS-ERECT. DAS-ERECT is implemented using the expert system development tool UNIK on SUN SPARC station. To accommodate the data availability during the implementation process, the two phased implementation approach is adopted. A series of experiments are performed using the real data to evaluate the performance of two systems. In the preliminary phase, an ideal system is developed regardles...한국과학기술원 : 경영과학과

Reactive Scheduling and Control for Shipbuilding : DAS-REACT

전체적인 조선 생산일정계획을 수립하기 위해서 계층적 구조를 채택하였다. 이 구조에 의하며 도크의 상위 일정계획 생성기는 탑재 일정계획을 생성하고, 조립공장의 하위 일정 계획 생성기는 상위 일정계획 생성기가 요구하는 범위 내에서 각각 세부적인 조립 일정계획을 세우게 된다. 그런데 하위 일정계획 생성기가 아무리 노력하여도 상위 일정계획 생성기로부터의 제약조건을 만족시킬 수 없는 상황이 발생하면, 일정계획 수정기에 통보하여 초기 탑재 일정계획을 수정해야 한다. 하위 일정계획 생성기로부터의 조정요청을 반영하기 위해서 부분 수정을 통해 충격을 최소화시키는 일련의 휴리스틱으로 구성된 알고리즘을 제시하였다. 각각의 휴리스틱은 여유시간 제가, 버퍼 제거, 작업시간 축소, 다단계 여유시간 제거, 과부하 자원 공유블럭 조정, 자원 제약조건 완화 등이고, 흡수되지 않은 일부의 충격은 주변으로 전파된다. 이와 같은 방법론을 대우조선의 상황에 적용하여, 조선 일정계획 수정 시스템인 DAS-REACT를 개발하였다

A study on the development of a computer-based information system for cash flow management in small and medium sized firms

학위논문(석사) - 한국과학기술원 : 경영과학과, 1986.2, [ [iv], 89 p. ]한국과학기술원 : 경영과학과