Research

year 1999 
author Seunghyun Yoon 
Keyword MRP, COM, UML, Object-Oriented, reusability 
Abstract The traditional descriptions of MRP systems always assume equal length time buckets, fixed manufacturing lead time, and infinite production capacity. This research presents new MRP method considering production capacity constraints and dynamic manufacturing lead time. Also the system´s data model is represented with UML(Unified Modeling Language), and its prototype is developed with COM(Component Object Model). This method uses event-driven approach. It schedules all the operations of a job to finite capacity when order is entered. To overcome the problem concerned with traditional bucket MRP, it applies bucketless MRP method which uses the minute as planned order´s time unit. To solve the problems concerned with fixed manufacturing lead time and infinite production capacity, it uses BOMfr(Bill of Manufacture). Because BOMfr integrates the BOM and routing data, capacity constraints and current states can be considered. When each machine´s schedule which is the base of MRP planned order is created, JOS(Job oriented scheduling) is used. The prototype system based on the idea of this research is developed with COM. The module that developed with COM component shows higher reusability and maintainability than traditional object-oriented system. MRP Logic COM is developed for the MRP system´s Logic. To store calculated data, MRP DB COM is developed which linked with Oracle 7.3 relational database. MRP Client links MRP Logic COM to MRP DB COM, and enables the user to input or output necessary data. Since MRP Logic COM is designed with object-oriented concept, it is feasible that linking MRP Logic COM to MRP DB COM which developed with object-oriented database. 
c MS 

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