• Journal of Korean Society for Quality Management
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• v.28 no.3
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• pp.11-17
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• 2000

This paper presents a model for determining the optimal number of general repairs and supplementary input cost limit rate in addition to minimal repair cost rate to implement preventive maintenance. The basic concept parallels the periodic replacement model with minimal repair at failure introduced by Barlow and Hunter(1960) and Park(1979), only difference being the replacement signalled by the number of previous general repairs performed on the system. A general repair brings the state of the system to a certain better state than before repaired. Numerical examples are provided.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.555-563
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• 1996

Nationwide incidence survey was conducted to estimate the annual incidence rates of colorectal cancer among Koreans between Jan 1, 1988 and Dec 31, 1989. The population of the incidence survey was the beneficiaries of Korea Medical Insurance Corporation (KMIC), which were about 4,500,000 persons. The medical records of patients with diagnosis of either ICD-9 153(colon cancer), 154(rectal caner), 197(secondary malignant neoplasm of digestive and respiratory system), or 211(benign neoplasm of digestive system) were abstracted for the period with the standard format. The diagnosis was confirmed by one oncologist through the review of these abstracts. The numerator of the rate was finally defined as the incident colorectal cancer cases diagnosed between July 1, 1988 and June 30, 1989. The crude annual incidence of colorectal cancer for men was 13.1 per 100,000 and 10.6 for women, which was still low when compared with those of Japan and China during the same period. Age-adjusted sex ratio was 1.2 for right-sided colon cancer and 1.9 for left-sided colon cancer. The excess of right colon cancer among postmenopausal women was remarkable, so further analytical approach would be needed to investigate which factors are related with this phenomenon.

• Journal of Preventive Medicine and Public Health
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• v.48 no.4
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• pp.188-194
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• 2015

Objectives: The goal of this study was to identify association between the continuity of ambulatory care of diabetes patients in South Korea (hereafter Korea) and the incidence of macrovascular complications of diabetes, using claims data compiled by the National Health Insurance Services of Korea. Methods: This study was conducted retrospectively. The subjects of the study were 43 002 patients diagnosed with diabetes in 2007, who were over 30 years of age, and had insurance claim data from 2008. The macrovascular complications of diabetes mellitus were limited to ischemic heart disease and ischemic stroke. We compared the characteristics of the patients in whom macrovascular complications occurred from 2009 to 2012 to the characteristics of the patients who had no such complications. Multiple logistic regression was used to assess the effects of continuity of ambulatory care on diabetic macrovascular complications. The continuity of ambulatory diabetes care was estimated by metrics such as the medication possession ratio, the quarterly continuity of care and the number of clinics that were visited. Results: Patients with macrovascular complications showed statistically significant differences regarding sex, age, comorbidities, hypertension, dyslipidemia and continuity of ambulatory diabetes care. Visiting a lower number of clinics reduced the odds ratio for macrovascular complications of diabetes. A medication possession ratio below 80% was associated with an increased odds ratio for macrovascular complications, but this result was of borderline statistical significance. Conclusions: Diabetes care by regular health care providers was found to be associated with a lower occurrence of diabetic macrovascular complications. This result has policy implications for the Korean health care system, in which the delivery system does not work properly.

• Journal of Preventive Medicine and Public Health
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• v.34 no.4
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• pp.363-371
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• 2001

Objectives : To assess the degree of quality improvement (QI) implementation and to identify its associated factors. Methods : A mailed questionnaire survey of the QI staffs at hospitals with 400 beds or more was conducted between September 15 and October 30, 2000. Of the 108 hospitals eligible for inclusion in our study, 79 participated, yielding a response rate of 73.1%. After excluding 12 hospitals that did not perform any QI activities, 117 responses from 67 hospitals were used in our analysis. The degree of QI implementation was measured using the Malcolm Baldrige National Quality Award Criteria (MBNQAC). Factors evaluated for association with the degree of QI implementation were cultural, technical, strategic, and structural factors of the hospitals. Results : The average 01 implementation score across the 7 dimensions of MBNQAC was 3.34 on a 5-point scale, with the highest score for the area of customer satisfaction (3.88) followed by information and analysis (3.59) and quality management (3.35). The results of regression analysis showed that hospitals with a ofter information system (p<0.05) and using scientific and systematic problem solving approach (p<0.01) tended to perform a higher degree of QI implementation. While statistically insignificant, positive associations were observed for the factors of group or developmental culture, the degree of employee empowerment, and the use of prospective strategy. Conclusions : It appears that the most important factors contributing to active implementation of QI in Korean hospitals were the use of scientific skills in decision making, and having a quality information system to produce precise and valid information.

• IE interfaces
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• v.19 no.3
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• pp.245-254
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• 2006

Equipments in container terminal have a lot of parts, and an equipment breakdown affects the productivity of terminal. In this paper, we develop a maintenance management system for improving reliability, availability and maintainability of equipments in container terminals. The developed system consists of five modules : equipment structure module, equipment operation management module, maintenance control module, spare part control module and data analysis module. The system supports reliability engineers to manage and improve RAM of equipments in container terminals. For example, FMEA, failure state analysis and life distribution parameters estimation are easily or automatically done by the system. This system also provides optimal preventive maintenance intervals by simulation and optimal yearly PM schedules for equipments in container terminal are recommended.

• Journal of Society of Preventive Korean Medicine
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• v.13 no.2
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• pp.115-128
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• 2009

Background : Currently, ontology research has led the trend of technical development in medical informatics area. For Korean medicine, the reference terminology should be developed to facilitate the ontology research. Objective : This research aimed to design the management system for traditional Korean medical terms. Method :We built the internet-based system in which multi-users work simultaneously by using the relational database system(SQL Server2005) and visual studio 2005. Result : By this system, researchers can collect, refine, and inspect Korean medicine terms efficiently, and the terms can be transcribed into synonym, Korean, Chinese, and simplified Chinese. It enables the terms be input into the system accurately and managed by its classification. Conclusion : We developed the concept groups and its hierarchy system for Korean medicine terms which provides the basis for ontology system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.1
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• pp.110-117
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• 2018

Machines and facilities are physically or chemically degenerated by continuous usage. One of the results of this degeneration is the process mean shift. By the result of degeneration, non-conforming products and malfunction of machine occur. Therefore a periodic preventive resetting the process is necessary. This type of preventive action is called 'preventive maintenance policy.' Preventive maintenance presupposes that the preventive (resetting the process) cost is smaller than the cost of failure caused by the malfunction of machine. The process mean shift problem is a field of preventive maintenance. This field deals the interrelationship between the quality cost and the process resetting cost before machine breaks down. Quality cost is the sum of the non-conforming item cost and quality loss cost. Quality loss cost is due to the deviation between the quality characteristics from the target value. Under the process mean shift, the quality cost is increasing continuously whereas the process resetting cost is constant value. The objective function is total costs per unit wear, the decision variables are the wear limit (resetting period) and the initial process mean. Comparing the previous studies, we set the process variance as an increasing concave function and set the quality loss function as Cpm+ simultaneously. In the Cpm+, loss function has different cost coefficients according to the direction of the quality characteristics from target value. A numerical example is presented.

• Magazine of the Korean Society of Agricultural Engineers
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• v.41 no.1
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• pp.52-59
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• 1999

Paddy rice is semi-tropical crop and requires warmirrigation water. If mean water temperature at the water source during the growing period is below 18$^{\circ}C$, sime kinds of water warming mechanism should be taken. In this study irrigation water temperature is measured and preventive measures to cold water damage on paddy rice are suggested. Field observations were performed at 100ha field area downtream of the Unmoon reservoir during the growing season of 1997. Land use, canal system, water temperature at irrigation canals. reservoir, and paddy fields were observed. In addition, growth and yield of the rice at selected plots were observed. Accordingly to the record, cold water damage occurred in this area due to the cold irrigation water supply in 1996. It did not occur because of the effective irrigation water management practice in 1997. However, several preventive measures such as pontoon intake system, using existing weir and construting a new warming pond, are suggested to prevent cold water damage in the future. If a new warming pond is construted to raise irrigation water temperature by 2 $^{\circ}C$, a pond area of 2.94 ha is required.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.328-330
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• 2007

Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. The state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect Maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

• International Journal of Control, Automation, and Systems
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• v.3 no.spc2
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• pp.334-340
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• 2005

Based on the stability margin provided by the EEAC, the unstable contingencies can be classified into sets according to their unstable modes. This two-part paper develops a globally optimal algorithm for transient stability control to coordinate preventive actions and emergency actions. In the first part, an algorithm is proposed for a set of contingencies having identical unstable modes. Instead of iterations between discrete emergency actions and continuous preventive actions, the algorithm straightforwardly searches for a globally optimal solution. The procedure includes assessing a set of insufficient emergency schemes identified by the EEAC; calculating the related preventive actions needed for stabilizing the system; and selecting the scheme with the minimum overall costs. Simulations on a Chinese power system highlight its excellent performance. The positive results obtained are explained by analogizing settlements for 0-1 knapsack problems using the multi-points greedy algorithm.