縫製工程에서 作業時間延遲이 完遂確率에 미치는 影響에 關한 硏究

Abstract

Today's industries in Korea currently introduce and utilize s newly innovated kind of method in the management to increase productivity and maintain costdown, i.e., scientific management emerges as one of the most important, principles for the enterprise. Almost, all the apparel-manufacturing factories necessitate expansion of facilities for exportation and mass production to meet the increased demand. This industry has as a labor-intensive one been rapidly grown having been backed ap by low wage costs, but conventional, domestic industry system of management, durbs setting up a detailed plan of production, which brings about a drastic reduction of productivity. This study intends to examine critical paths based on the PERT/TIME theory that have not been attempted in Jacket-making factories, simultaneously to inquire into quantitative and qualitative figures of delay ratio said delay time to determine performance probability deriving from the process delay occurred when manpower, raw materials, facilities have not been sufficiently supplied in time and in the right places. For the method of study, a time study is made on each path according to the model established, average working time is obtained, a flow chart and network are made, then Earliest Node Time and Latest Node Time are obtained. From this Total Float Time is determined, and critical paths are grasped. According to Three Point Estimation through each of nodes on C.P., Expected Node Time and its value Ui respectively in delay ratio and ti^E_4 constant cases are obtained and φ (Ui) is gained according to the table of standard normal distribution. The resultant findings are as follows; a. Performance probability increases quantitatively as delay ratio increases in each of nodes and nodes proceed. b. Delay ratio shows the highest probability on Node 12 hy 7%, on Node 204 by 3%, on Node 205 by 5%, which reveals sharp discrepancy toward a dull increase of other process, and necessitates intensified handling. c. As the ratio increases and nodes proceed, differentials in performance probability increase more rapidly than an increase of the ratio. d. Performance probability decreases qualitatively when delay fixed time increases in each of nodes and nodes proceed. e. As the earliest node time on overall process is delayed, material ordering indicates performance probability of 36%, bottom bemming, 5%. f. Variation of performance probability in specific nodes is analogous to logistic or compertz curve. In the final analysis, the establishment of a shortest time on each process in apparel-manufacturing factories would suggest a good principle to work out an appropriate plan under which manpower, facilities, and raw materials could be supplied in time. It is desired that further studies should be made on the ideal models in preparedness for the case of specific time allotment, not of S.N.D., and of limited manpower, raw materials, etc.