• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.99-106
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• 1999

This paper considers an imperfect repair model for which the repairable system is maintained preventively at periodic times and is replaced by a new system when a predetermined number of preventive maintenance has been applied. our main objective of this is to determine the optimal number of preventive maintenances before the system is replaced and the optimal length of interval between two consecutive preventive maintenances under a new repair model which is referred to as an ineffective preventive maintenance. Such a model assumes a periodic preventive maintenance in which the system is effectively maintained with a certain probability. Otherwise the system is not improved at all after each maintenance and thus the failure rate remains the same as before. The criteria to determine the optimal number of preventive maintenances and length of period is the expected cost rate per unit time for an infinite time span. We give the explicit expressions for the expected cost rate per unit time. Some numerical examples are presented for illustrative purposes.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.19 no.2
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• pp.313-319
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• 2006

Background and Objective : Localized Pustular Psoriasis(LPP) is a rare form of psoriasis characterized by erythematous papules, plaques studded with pustules(usually on palms or soles) However, the pathophysiology of the LPP remains obscure. Treatment at present is symptomatic and supportive. There is no report on LPP treated with oriental medical treatment. Methods : We conducted one patient with LPP seen at Won-Kwang University Ik-San Oriental Medical Hospital in 2003. We treated LPP in a forty-nine years old man by a herbal medicine, acupuncture, moxa, etc Conclusions : We had a significant results. So we report this case to estimate the efficiency of oriental medic at treatment and management on LPP

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1388-1392
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• 2008

Water resources management depends on dealing inherent uncertainties stemming from climatic and hydrological inputs and models. Dealing with these uncertainties remains a challenge. Streamflow forecasts basically contain uncertainties arising from model structure and initial conditions. Recent enhancements in climate forecasting skill and hydrological modeling provide an breakthrough for delivering improved streamflow forecasts. However, little consideration has been given to methodologies that include coupling both multiple climate and multiple hydrological models, increasing the pool of streamflow forecast ensemble members and accounting for cumulative sources of uncertainty. The approach here proposes integration and coupling of global climate models (GCM), multiple regional climate models, and numerous hydrological models to improve streamflow forecasting and characterize system uncertainty through generation of ensemble forecasts.

• International Journal of Reliability and Applications
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• v.1 no.1
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• pp.15-26
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• 2000

This paper considers an aperiodic preventive maintenance (PM) model for repairable systems, in which the time intervals between two consecutive preventive maintenances are unequal. To propose such an aperiodic PM model, we assume that each PM reduces the current hazard rate by a certain amount which depends on the number of PMs performed previously. If the system fails between PMs, the minimal repair is performed and the hazard rate remains unchanged after the repair. We give the exact expressions for the hazard rate function for the aperiodic PM model. Based on the proposed aperiodic PM model, we suggest the maximum likelihood method to estimate the parameters characterizing the model and apply the method to the case of Weibull distribution. Numerical examples for estimating the parameters are presented for the purpose of illustration.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.1
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• pp.15-22
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• 2017

Although there are many efficient techniques to minimize the speed gap between processor and the memory, it remains a bottleneck for various commercial implementations. Since secondary memory technologies are much slower than main memory, it is challenging to match memory speed to the processor. Usually, hard disk drives include semiconductor caches to improve their performance. A hit in the disk cache eliminates the mechanical seek time and rotational latency. To further improve performance a divided disk cache, subdivided between metadata and data, has been proposed previously. We propose a new algorithm to apply the SSD that is flash memory-based solid state drive by applying FTL. First, this paper evaluates the performance of such a disk cache via simulations using DiskSim. Then, we perform an experiment to evaluate the performance of the proposed algorithm.

• Transactions of Materials Processing
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• v.23 no.1
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• pp.5-9
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• 2014

Although much research has been conducted to reduce the thickness of PET bottles in order to save manufacturing costs, the challenge remains of guaranteeing mechanical strength for top-loaded thin PET bottles. The current study investigates the large deformation characteristics of a circle shaped PET bottle and a square shaped PET bottle when compressively loaded using FEA. The arc length method is used in the nonlinear FEA to understand the buckling phenomenon. For PET bottles with the same capacity, the circle shaped bottle shows more resistance to buckling and compression loading than the square shaped bottle.

• Journal of KIBIM
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• v.8 no.1
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• pp.1-14
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• 2018

Domestic and foreign software components are rapidly developing continuously. However, the government's plan to activate BIM remains relatively sluggish. In particular, BIM based information management systems have been developed to enable the development of degraded railway industries in infrastructure BIM based areas. For this purpose, we analyzed domestic and oversea policies and guidelines. We conducted a survey on the personnel of the railroad corporation. Based on the survey result, the elements applicable to BIM were reflected in the system.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.108-111
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• 2001

The electric power industries in Korea are launched into deregulation by introducing the CBP(Cost Based Pool), where generation sector of KEPCO was divided into six generation companies and the other sectors of KEPCO remains vertically integrated system. In deregulated market, participants are concerned with maximization of their profit rather than minimization of system-wide costs. Consequently, there are difficulties in applying the cost minimization for the scheduling of generation resources to CBP, because of the operation of pumped-storage hydroplants. This paper presents an operation method of pumped storage hydroplants which is helpful for the economic operation of power system considering the market in the CBP.

• Tuberculosis and Respiratory Diseases
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• v.79 no.1
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• pp.1-4
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• 2016

Tuberculosis (TB) remains a major public health problem in South Korea. The Joint Committee for the Development of Korean Guidelines for Tuberculosis published the Korean Guidelines for Tuberculosis in 2011 to provide evidence-based practical recommendations to health care workers caring for patients with TB in South Korea. After reviewing recent national and international scientific data on TB, the committee updated the Korean guidelines for TB in 2014. This article presents some practical issues related to the 2014 updated guidelines: namely use of the Mycobacterium tuberculosis-polymerase chain reaction assay and the Xpert MTB/RIF assay in the diagnosis of TB, as well as medical treatment for patients with multidrug-resistant TB.

• Clinical and Experimental Pediatrics
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• v.50 no.5
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• pp.422-429
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• 2007

Measurement of lung function is an integral component of respiratory physiology and of clinical assessment of lung diseases in school age children and adults. Pulmonary function test of infants and children under the age of 2 years have now been standardised and are being used both in research and as an adjunct to clinical management. By contrast, until recegntly, children of preschool age, i.e. between 2-6 years represented a major challenge for pulmonary function test assessment, this particular period commonly being referred to as the 'dark ages' of Pediatric Pulmonology. Measurement of lung function in preschool-aged children is now feasible. However, much work remains to be done in standardizing how these tests are performed, and in understanding the most appropriate role for the various tests in the study of growth and development of the respiratory system and in the clinical management of children in this age group. As the field develops and the knowledge of respiratory physiology in this age group expands, investigation of different and more appropriate algorithm use in preschool children, together with development of more appropriate reference data, may result in improved disease discrimination.