• Industrial Engineering and Management Systems
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• v.11 no.1
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• pp.48-53
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• 2012

Due to the customer needs of reducing cost and delivery date shorting, prompt change in the production plan became more important. In the multi period system (For instance, production line.) where target processing time exists, production, idle and delay risks occur repeatedly for multiple periods. In such situations, delay of one process may influence the delivery date of an entire process. In this paper, we discuss the minimum expected cost of the case mentioned above, where the risk depends on the previous situation and occurs repeatedly for multiple periods. This paper considers the optimal switching frequency to minimize the total expected cost of the production process. In this paper, first, the optimal switching frequency model is proposed. Next, the mathematic formulation of the total expectation is presented. Finally, the policy of optimal switching frequency is investigated by numerical experiments.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.39 no.3
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• pp.147-155
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• 2016

Industry 4.0's goal is the 'Smart Factory' that integrates and controls production process, procurement, distribution and service based on the fundamental technology such as internet of the things, cyber physical system, sensor, etc. Basic requirement for successful promotion of this Industry 4.0 is the large supply of semiconductor. However, company I who produces dicing blades has difficulty to meet the increasing demand and has hard time to increase revenue because its raw material includes high price diamond, and requires very complex and sensitive process for production. Therefore, this study is focused on understanding the problems and presenting optimal plan to increase productivity of dicing blade manufacturing processes. We carried out a study as follows to accomplish the above purposes. First, previous researches were investigated. Second, the bottlenecks in manufacturing processes were identified using simulation tool (Arena 14.3). Third, we calculate investment amount according to added equipments purchase and perform economic analysis according to cost and sales increase. Finally, we derive optimum plan for productivity improvement and analyze its expected effect. To summarize these results as follows : First, daily average blade production volume can be increased two times from 60 ea. to 120 ea. by performing mixing job in the day before. Second, work flow can be smoother due to reduced waiting time if more machines are added to improve setting process. It was found that average waiting time of 23 minutes can be reduced to around 9 minutes from current process. Third, it was found through simulation that the whole processing line can compose smoother production line by performing mixing process in advance, and add setting and sintering machines. In the course of this study, it was found that adding more machines to reduce waiting time is not the best alternative.

• The Korean Journal of Food And Nutrition
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• v.19 no.2
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• pp.234-241
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• 2006

The purpose of this study was to provide basic information about the usage frequency of foods and menu items that may have microbiological hazards in elementary school foodservice operations in order to prepare a sanitation management manual for the foodservice production process. Menus from 200 elementary school foodservice operations from June 2004 were analyzed. An analysis of the foodservice production process of the menu revealed that the following processes were used: heat process(63.9%), non-heating process(28.1%), and after-heating process(8.0%). The cooking methods used for side dishes were: Stir-frying(19.9%), Saenchae(15.6%), Jorim(15,1%), Sukchae(13.1%), Frying(11.3%) and so on. Overall, 85 menu items known to include microbiological hazards were offered a total of 3,537 times; they were Doegi-bulgogi(7.0%), Bibim-bap(5.2%), Oi-saengchae(4.6%), Kongnamul-muchim(4.2%), Ddeok-bokkeum(4.0%), Japchae(3.7%), and so on. To serve safe and hygienic foods, menus including microbiological hazards should be planned very carefully. Furthermore, if a menu is high in microbiological hazards and frequency, the manuals of sanitation management should be applied more thoroughly.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.521-525
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• 2004

The objective of this study is to implement a WBS (Work Breakdown Structure) so as to support efficient information management through the construction process of Steel Box Girder Bridge. To meet this requirement. This study performs the analysis of the business process. Through the work, information flows and information management levels are identified. Information management in each manufacturing process was various in its level. For the efficient information management, skating and utilization in schedule, cost, resource, and quality management, it is recommended to utilize a WBS composed of major work section and element structure of the steel box girder.

• Journal of Korean Society of Archives and Records Management
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• v.20 no.4
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• pp.19-40
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• 2020

Deficiencies are present in records management during the production stage of long-term electronic records preservation. As such, this study seeks to address these issues by introducing Cloud On-Nara System (On-Nara Document 2.0) at records management sites and providing various systems and linked services. In particular, the factors that degrade the continuity of long-term preservation in the records management process, from the production to the utilization of electronic records, in On-Nara Document 2.0 were identified, and the causes were analyzed in compliance with ISO 15486-1:2016 and the Public Records Act. As a result, in redesigning the records management procedure, the organization of the records management hub between systems and the conversion of the document preservation format for long-term preservation were proposed. Moreover, the application of consistent production format selection criteria and the reinforcement of the production and management of granular metadata were recorded. These measures were proposed in an effort to reestablish management methods.

• Journal of Korean Society for Quality Management
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• v.38 no.4
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• pp.540-548
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• 2010

We consider the problem of selecting the most profitable initial process mean and length of production cycle for manufacturing processes subject to a constant linear trend during the same cycle that varies after resetting the processes. Assuming that the quality characteristic of interest is normally distributed, the optimum initial process mean and the length of production cycle are jointly obtained by minimizing the expected loss per unit time. We assume that the quality loss function due to the deviation from the target value is quadratic and resetting loss is constant. We consider both cases of symmetric and asymmetric quality loss function. An illustrative example is given and sensitivity analysis performed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.31 no.2
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• pp.1-10
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• 2008

In the knowledge-based society which recognizes knowledge as a core value, knowledge management is one of the most interesting issues. The creation of knowledge within an organization occurs as a result of interactions of tacit and explicit knowledge, in process of knowledge conversion. One useful model of this process is the SECI model which stands for a process of socialization, externalization, combination and internalization of knowledge. The enterprise competitive power depends on how an organization accelerates the speed of the cycle of knowledge creation well. In this paper we introduce a knowledge management promotion system based on SECI model and proposal system to promote the cycle of knowledge creation in production fields, and study an enterprise case.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.67-73
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• 2010

This study began the study by instructing enterprises to change Batch Production into U-Line. This study suggested TPS U-Line building model process and applied it to some of their product line. By connecting concerned process elements into continuous operations. Outside orders were also switched to inside operations and executed in continuous operations, thereby about 100Km of transit distance became zero Km, Production lead Time was incredibly reduced. After all, 90% of Production Lead Time, 50% of handling fault, 3/4 of workers decreased and Productivity per Person enhanced which involves improving Batch Production into Continuous Production and applies it to the real world, so that small and medium enterprises can consult this study if the company is willing to make an improvement to their product line.

• Korean Management Science Review
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• v.31 no.3
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• pp.27-39
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• 2014

We derive a generalized statistic form of Q control chart, which is especially suitable for short run productions and start-up processes, for the detection of process mean shifts. The generalization means that the derived control chart statistic concurrently uses within lot variability and between lot variability to explain the process variability. The latter variability source is noticeably prevalent in lot type production processes including semiconductor wafer fabrications. We first obtain the generalized Q control chart statistic when both the process mean and process variance are unknown, which represents the case of implementing statistical process control charting for short run productions and start-up processes. Also, we provide the corresponding generalized Q control chart statistics for the rest of three cases of previous Q control chart statistics : (1) both the process mean and process variance are known (2) only the process mean is unknown and (3) only the process variance is unknown.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.12
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• pp.2906-2913
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• 2013

Only small numbers of medium-sized manufacturers have adopted a production management system. They have difficulty maintaining production cost and progress management, because they have used the ways that win a contract, not mass production system like a big company. Also a small company has to change standard features of products whenever customers want, by means of non-standardization and small quantity production method. As a result, it has been very difficult for a small company to establish a proper production management system. So, this paper tried to make a study about increasing production management system, using QR codes in a small-sized manufacturer with the ways that win a contract, based on real application case.