In order to satisfy various desires of consumers, a company should produce a variety of products and the production lot size should be as small as possible inevitably. Then, it requires frequent setup works for the model changes. Since setup works are usually carried out after stopping the operation of the equipment, we must minimize the time required for setup works. Major companies are continuously shortening the setup time over the technical guidance from the leading companies, such as Toyota and their own improvement activities up until now. But small and medium-sized(S&M) companies rely on skills and experience of individual engineers due to lack of the personnel and budget. In this paper, we propose systematic guidelines for writing the setup operation manual to support S&M companies. Major functions of the guidelines are drawing process charts specialized in the setup operation, separating the external and internal setup operations, and minimizing internal setup operations. By utilizing the guidelines, it is expected that S&M companies can prepare and apply their own setup operation manual with a minimum of manpower and money. Then, they can manage setup works in a more efficient and reduce the setup time and lower the production cost.
This paper deals with the production plan for the foaming process, the core part of the refrigerator manufacturing process. In accordance with this change, the refrigerator manufacturing process has also been converted into the mixed-model production system and it is necessary to optimize the production release pattern for the foaming process. The pattern optimization is to create a mixed-model combination which can minimize the number of setup operations and maintain mixed-model production. The existing method is a simple heuristic that depends on the demand priority. Its disadvantages are low mixed-model configuration rate and high setup frequency. Therefore, demand partitioning occurs frequently. In this study, we introduce the tolerance concept and propose a new pattern optimization algorithm based the large neighborhood search (LNS). The proposed algorithm was applied to a refrigerator plant and it was found that mixed-model configuration rate can be improved without demand partitioning.
The up-to-date small and medium-sized enterprises (SMEs) in Korea have tried to respond flexibly and rapidly to dynamic business environment and to establish efficient production management system based on information technologies. However, most of SMEs have faced with low applicability of the production management system resulting from high costs of introduction and maintenance. In this paper, a production planning and control system, that is S-PMS (production management system for SMEs), is proposed to solve the problem of low applicability and limited human resources. S-PMS enables production managers to efficiently collect and manage master data with the actual target production systems and explores the bottleneck process by means of simulation techniques to improve productivity. Furthermore, it implements rescheduling mechanism in terms of a variety of process routes. In essence, intuitive dispatching rules and integrated data management of S-PMS improve field applicability of production management system. Consequently, S-PMS is expected to be used as an efficient production management system of SMEs in Korea.
Self-efficacy (one's perceptions of their capability to perform a task) plays an important role in work-related performance and motivation. For example, self-efficacy is known to have much influence on job performance, job satisfaction, motivation, etc. As such it is important to know what factors collectively enhance the selfefficacy of employees, so that injured workers contribute to the organization they belong to after they come back to their workplace. The aim of this study is to identify such industrial accident-related factors and extract rules among the factors in order to establish self-efficacy enhancement strategies for injured workers. In this study, a binary decision tree model for self-efficacy prediction was built using a panel data provided from Korea Workers’ Compensation & Welfare Service. As a result, eight variables with the largest influence on self-efficacy were selected in the prediction model, and it correctly classified 70.1% of instances. The result suggests social support during the treatment period and offering paid time off such as vacation leave, sick leave and bereavement leave are important factors to enhance self-efficacy that will improve the work performance of injured workers.
The major issue in aircraft industry is aviation safety management because of demand improvement and advancement of the aircraft. This study is to assess the risks for aviation safety management using IRPN( importance-risk priority number) which is added to importance coefficient from RPN(risk priority number). In FMEA, RPN requires the factors like the occurrence (O), Severity (S), and Detection (D) of each failure mode to be precisely evaluated. Therefore, the severity and detection is derived by the value from FMEA of expert group based on the Fuzzy theory. The occurrence is calculated from the accident statistics of IATA(international air transport association) database. Particularly, this study introduces importance coefficient to prevent from RPN distortions. It is also derived from FMEA based on the Fuzzy theory. Finally, the critical ranking of risk factors according to I-RPN is compared with the existing research.
Recently, transaction data is accumulated everywhere such as bank and IT company. Association analysis methods are usually applied to analyze transaction data, but the methods have several problems. For example, these methods only consider one-way relations among items and cannot reflect domain knowledge to analysis process. In order to overcome defect of association analysis methods, we suggest a transaction data analysis method based on probabilistic graphical model (PGM) in this study. The method we suggest has several advantages as compared with association analysis methods. For example, this method has a high flexibility, so it can give a solution to various probability problems regarding the transaction data and can consider various relationships among items.
Control chart is a graph of plotting dot in the process characteristic values. It is a statistical technique that can be known whether or not the in-control state in this step. In many companies have use as a statistical process control(SPC) tool. Control chart is the management process quality characteristic value, which is plotted dot is whether the existence within the control limits. But, this is not given information about the economic loss that occurs when a product is produced characteristic value does not match the target value of the process. In that sence, expected loss control chart(EL control chart) is very effective process control tool. Because it is a process control chart in consideration to economic loss. The EL control chart is using the quadratic loss function of Taguchi. However, Taguchi’s quadratic loss function is simple quadratic curve. It is difficult to realistically reflect the increased amount of loss that due to a deviation from the target value. In this paper, we design a new control chart using the reflected normal loss function(RNLF). And we demonstrate its effectiveness by using the control chart performance comparison of EL control chart.
There can be included a variety of uncertainties in all measurement results whether we can perceive or not on the causes. These uncertainties may end up in lowering the reliability of measurement results and also deteriorate the level of quality. For the purpose of finding and improving these causes , we tried to combine the strengths of measurement uncertainty and measurement system analysis together to present a practical flowchart so as to verify those potential variation factors in general measurement processes. Through the case study we have come to a conclusion that we can expect engineers who are involved in quality and measurements to utilize this developed method.
IT security service protects their networked information asset and infrastructures using experts’ knowledge. To improve its service quality, by exploring quality factors and assessing the quality level, an approach based on a research model is required. Several research models have been proposed and used in various service area, but few cases of IT security service are found. In this work, a research model of service quality has been proposed, based on the existing research models such as SERVQUAL and E-S-QUAL. The factors which affect the quality of IT security service and the best quality measure including quantitative measures have been identified. By comparing them, the feasibility of using quantitative measures for quality measures has been addressed. For analysis, structural equation modeling and various statistical methods were used. The result shows that, among the three quality measures, satisfaction is the most significantly affected one by quality factors. The quantitative measures show positive correlation with other perceived quality measures. The analysis of the result provides several suggestions which can be used in measuring and improving the quality of IT security service. Emotional factors such as empathy are as important as the swiftness of service, which leads to a strategy of quality improvement based on customer satisfaction, not solely on technology only. And, in order to design reliable quantitative measures, standards such as rational target processing time should be first established. The work of this research will provide efficient tools to improve the quality of IT security service and help the quality research for other service areas.
Quality has been one of the critical issues in modern industry. Korean government has performed quality competitiveness assessment targeted on manufacturing industry, construction industry, and public service sector since 1997. Korean government first asks for them to evaluate quality competitiveness by themselves. An expert group consisted of faculty members in universities assesses the results of the self-evaluated quality competitiveness. The audit data assessed by the expert group are finally reevaluated in public and the ministry of trade, industry, and energy confers a title for best enterprise every year. We statistically analyze the final audit data for quality competitiveness assessment in 2014. We aim to figure out the characteristics based on business size – large-size company or small and medium-size company, the ownership-public or private company, the types of business, and the level of quality competitiveness. The results of data analysis are summarized and the implications are stated.
Importance-Performance Analysis(IPA) holds the assumption that the degree of physical fulfilment of quality attributes and the satisfaction of that attribute is linear. Therefore, IPA can be applied to the traditional one-dimensional attributes, not to other quality elements such as attractive or must-be attributes. To overcome this problem, several articles introduced methods that integrate IPA into the concept of two-dimensional quality. However, these articles are rather conceptual focusing on the differentiation of quality attributes depend on quality elements in IPA. To provide empirical evidence of the dependent relationship between attribute importance and satisfaction in IPA, this study introduces a weighted importance approach and provides validation method using Bacon(2003)’s priority model, a regression model. For this, the current research investigates 23 quality attributes of TV set for the results of Kano’s model, which are adopted from Kim et al.(2013), and conducted a survey of 118 university students for the results of the importance/satisfaction and improvement priority. The result of the proposed approach shows better result than those using the conventional way, based on R-square of the regression model.
When offense launches missiles at valuable assets of the defense, the defense must assign its weapons to these missiles so as to maximize the total value of surviving assets threatened by them. Recently, a new asset-based linear approximation model was proposed for weapon target assignment problem with shootlook- shoot engagement policy and fixed set-up time between each anti-missile launch from each defense unit. In this paper, we apply the proposed to several ballistic missile defense examples and we show their weapon target assignment results specified with launch order time.
Design in small hydro power systems is the detailed work required a variety of epidemiological considerations. However, turbine designers were often feel the limitations due to repetitive calculations or drawings, rather than focusing on finding the turbine performance and efficiency improvements. Furthermore, miss the point in repeating the procedure design process or cross the interface is not easy to keep track of the changes required parameters should also feel the difficulties in efficient design. Improve this unreasonable points, though he design part is insufficient understanding of the hydro turbine, to automate the design to exclude the repetitive operations is the purpose of this study
This paper considers a paternity and kinship analysis system(PKAS) being currently used in real sites. A knowledge-based expert system is proposed to improve the performance of PKAS in terms of accuracy, speed, training time, and satisfaction, which are common measures for evaluation. The knowledge base, one of the most important components in the knowledge-based expert system(KBES), consists of a rule made from random matching algorithm, decision rules of allele types and guide rules of options. The last two rules are learning incrementally from sample data. The results show that PKAS armed with the expert system ensures the better performance with regard to these criteria than the existing system. Especially as far as speed is concerned, as the sample size increases, it outperforms the existing one. As the number of samples increases, while processing time increases nearly exponentially in the existing PKAS, it does linearly in our proposed system.
Recently, there have been keen interests in regeneration of old industrial parks. Applying for policies and business, various indices on deterioration of inner industrial parks have been researched. However, to make regeneration projects work in actual, the condition of economic feasibility has to be met. This study focused on the economic condition of regeneration by enlarging existing indices to those of surrounding area and location as well as business environment. By applying the indices to 83 old industrial parks, which are more than 20 years old, 8 types of involvement in regeneration projects have been deduced. Among 8 types, the most frequently appeared cases were type 4 and 5, which are appropriate for regeneration and restructuring respectively.