• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.38 no.3
• /
• pp.78-86
• /
• 2015

Up-to-date business environment for manufacturers is very complex and rapidly changing. In other words, companies are facing a variety of changes, such as diversifying customer requirements, shortening product life cycles, and switching to small quantity batch production. In this situation, the companies are introducing the concept of JIT (just-in-time) to solve the problem of on-time production and on-time delivery for survival. Though many companies have introduced ERP (enterprise resource planning) systems and MRP (material requirement planning) systems, the performance of these systems seems to fall short of expectations. In this paper, the case study on introducing an APS (advanced planning and scheduling) system based on dispatching rules to a machining company and on finding a method to establish an efficient production schedule is presented. The case company has trouble creating an effective production plan and schedule, even though it is equipped with an MRP-based ERP system. The APS system is applied to CNC (computer numerical control) machines, which are key machines of the case company. The overall progress of this research is as follows. First, we collect and analyze the master data on individual products and processes of the case company in order to build a production scheduling model. Second, we perform a pre-allocation simulation based on dispatching rules in order to calculate the priority of each order. Third, we perform a set of production simulations applying the priority value in order to evaluate production lead time and tardiness of pre-defined dispatching rules. Finally, we select the optimal dispatching rule suitable for work situation of the case company. As a result, an improved production schedule leads to an increase in production and reduced production lead time.

• Advances in Computational Design
• /
• v.4 no.2
• /
• pp.179-196
• /
• 2019

Temporary scaffold systems in the construction site play an important role for ensuring the safety of the workers and for constructing the stable structures. To assemble the scaffold, the pipe scaffolding system, the wedge binding scaffolding system and the particular materials have been utilized. To design the material arrangement of a scaffold, firstly the configuration was determined considering the construction geometry. Then, the strength of the scaffold was confirmed and the quantity of the material was accounted. In this paper, the design method of the temporary scaffold was proposed for intending the semi-automatic procedure. In the proposed design method, the geometric design and the safety requirement were specified by the safety standard and the design flow was followed by the designer's knowledge. The size and the quantities of the materials were calculated by referring to the relation between the scaffold and the constructing structure. In the calculating procedure, three dimensional positions of each scaffold materials were calculated and recorded simultaneously. Then, three dimensional scaffold structural was drawn semi-automatically on the CAD software by using the obtained material sizes, positions and directions. The proposed design method provides us the precise quantities of scaffold materials and enables us to reduce the design effort and the cost estimation processes. In addition, the obtained results can be applied to BIM software after converting to IFC format.

• IE interfaces
• /
• v.15 no.4
• /
• pp.325-337
• /
• 2002

In this study we consider the problem of production planning of TFT-LCD(Thin Film Transistor - Liquid Crystal Display) production factory. Due to the complexities of the TFT-LCD production processes, it is difficult to schedule the production planning, and the study about automated scheduler is insufficient. In addition, the existing production method is a Push-System to raise the operation rate with expensive equipment, that has the problem to satisfy the due-date. This study presents an algorithm having a concept of Pull-System that satisfies the due-date and considers specialties of TFT-LCD production process. We make MPS(Master Production Schedule) according to the sales order, and present algorithms for scheduling about In/Out plan considering factory capacity, line balancing, material requirement, and inventory level of all Array, Cell, and Module processes. These algorithms are integrated as an automated production system, and we implement them in the actual TFT-LCD factory circumstance.

• Korean Journal of Computational Design and Engineering
• /
• v.16 no.3
• /
• pp.187-196
• /
• 2011

Generally, BOM (Bill of Material) means a part list which is needed to manufacture or assemble a product or part. During manufacturing processes, BOM is inevitably required for most of enterprise processes such as design, procurement, production planning/control, resource planning, and financial works. Every manufacturing industry uses many kinds of BOM's that are adjusted to the requirement of functions of their work division. Moreover, BOM evolves in different forms according to the product development phases such as conceptual design; function design, detail design, and production design because it is necessary to use different product structures to keep product data generated throughout the lifecycle of a product. This includes all data and information related to the all the product development phases. Shipbuilding works also are processed and controlled based on BOM. However, effective maintenance of ship outfitting BOM data is getting difficult as the amount and complexity of data have increased due to variety and long lifecycle of ship. For the effective management of outfitting BOM data, two aspects must be considered. One is how to classify numerous BOMs type and the others how to display BOMs. So this study suggests a method to classify BOM types and propose two categories - Structure BOM, Display BOM. Base on this result, we propose the integrated ship outfitting BOMs model and analysis outfitting BOMs.

• Proceedings of the Korea Inteligent Information System Society Conference
• /
• 2002.05a
• /
• pp.429-434
• /
• 2002

For companies assembling end products from sub assemblies or components, MRP (Material Requirement Planning) logic is frequently used to synchronize and pace the production activities for the required parts. However, in MRP, the planning of operational-level activities is left to short term scheduling. So, we need a good scheduling algorithm to generate feasible schedules taking into account shop floor characteristics and multi-level job structures used in MRP. In this paper, we present a GA (Genetic Algorithm) solution for this complex scheduling problem based on a new gene to reflect the machine assignment, operation sequences and the levels of the operations relative to final operation. The relative operation level is the control parameter that paces the completion timing of the components belonging to the same branch in the multi-level job hierarchy. In order to revise the fixed relative level which solutions are confined to, we apply large step transition in the first step and GA in the second step. We compare the genetic algorithm and 2-phase optimization with several dispatching rules in terms of tardiness for about forty modified standard job-shop problem instances.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.187-190
• /
• 2005

There have been many studies to improve the performance of a database system focused on modifying data structure, data partitioning, and materializing strategy. The main contribution of this study is to propose a new alternative towards improving database performance by designing single table schema or processing queries virtually in main memory space. Material Requirement Planning(MRP) part explosion process has shown almost 2 times shorter under DB schema we suggested, and even more than 10 times shorter when separating and filtering policy of DB archiving process are assumed. Several experimental results are shown to illustrate the excellence of our solution.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.183-186
• /
• 1996

The relational database management systems sometimes require extremely long and complicated queries for a certain retreval. In this case, recursive retirevals are more efficient approach than the usual queries. Many researchers have tried to incorporate semantics in the traditional relational models using artificial intelligence techniques. This new concept becomes a deductive database and sometimes it is also called as a logic programming. However, the designer of a deductive database did not overcome the short of relational database. In this paper, we propose a new way of designing queries for the deductive database. We also provide relations for recursive retrieval in the deductive database. These approaches are applied for the material requirement planning.

• Journal of Korean Society for Quality Management
• /
• v.18 no.1
• /
• pp.65-76
• /
• 1990

A lot-sizing model for multi-stage MRP systems is proposed, in which known demands must be satisfied. In this model, an approach with considerations of initial inventory and limited production capacity is involved. Most of the studies on the lot-sizing techniques for multi-stage material requirement planning systems have been focused upon two basic approaches. One approach is to develope an algorithm yielding an optimal solution. Due to the computational complexity and sensitivity of the optimal solution to the problem of lot sizing, heuristic approaches are often employed. In this paper, the heuristic approach is used by sequential application of a single-stage algorithm with a set of modified cost by the concept of multi-echelon costs. The proposed method is compared with an lot-sizing method(Florian-Klein Model) to prove its effectiveness by numerical examples.

• Journal of the Korea Society for Simulation
• /
• v.21 no.3
• /
• pp.25-33
• /
• 2012

Ptak & Smith published ORLICKY'S Material Requirement Planning Third Edition in 2011 to correspond the rapidly changed market demand by improving the original MRP based on Theory of Constraints(TOC) replenishment inventory management. This study is to develop the simulation model to decide the proper target inventory level for TOC replenishment inventory management using system dynamics Vensim software. This study shows that the proper target replenishment level is how much significant to manage the inventory by the random sample data simulation. This simulation model will be extended to compare the results of the TOC replenishment inventory management planning with the results of the old MRP planning by the enterprise actual inventory data.

• Journal of Family Resource Management and Policy Review
• /
• v.4 no.1
• /
• pp.95-111
• /
• 2000

The family financial management is the important element which has a effect on the improvement of family economic well-being. Thus the study sets up human & material resources and requirement as an input factor, family financial management as an throughput factor, and economic well-being as an output factor, and then identifies if there are some relationships among them by using a systematic approach of family financial management. The questionaires were distributed to 600 employed wives by carrying out cluster sampling and disproportional stratified sampling. The 573 cases of them were used as the mean, ratio, Pearson’s Correration, ANOVA, factors analysis, and Stepwise Regression using the SAS/PC+. The major findings of the study are as follows: 1) A practical application of information as on input variable, appears the fator which has an important effect upon the throughput factor, that is, family financial management. The employed wives should manage a lot of resources in rapidly changing social-economic circustances. So it shows that not only they should take informations open to their daily life and then make practical use of them in managing their family finance, but also they must be capable of judging and accepting reasonable informations in order to gain and manage resources suitable to the characteristics of family finance and family members’need. 2) There was significant relationship between the employed wives’family financial management and family economic well-being, focused on the systematic theory of family financial management. This study provides for the information to develope the program for the employed wives’family financial planning and counseling.