• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.19 no.39
• /
• pp.89-98
• /
• 1996

This paper is concerned with cost analysis model in free -replacement policy under the periodic maintenance policy The free-replacement policy with minimal repairable item is considered as follows; in a manufacturer's view point operating unit is periodically replaced, if a failure occurs between minimal repair and periodic maintenance time, unit is remained in a failure condition. Also unit undergoes minimal repair at failures in minimal-repair interval. Then total expected cost per unit time is calculated according to maintenance period Tin a viewpoint of consumer's. The expected costs are included repair cost and usage cost: operating, fixed, minimal repair and loss cost. Numerical example is shown in which failure time of item has beta distribution.

• Journal of Applied Reliability
• /
• v.12 no.2
• /
• pp.57-66
• /
• 2012

In this paper, we consider the periodic preventive maintenance model for a repairable system following the expiration of replacement-repair warranty. Under this preventive maintenance model, we derive the expressions for the expected cycle length, the expected total cost and the expected cost rate per unit time. Also, we determine the optimal preventive maintenance period and the optimal preventive maintenance number by minimizing the expected cost rate per unit time. Finally, the optimal periodic preventive maintenance policy is given for Weibull distribution case.

• Journal of the military operations research society of Korea
• /
• v.15 no.1
• /
• pp.54-62
• /
• 1989

This paper presents a corrective maintenance model to determine either type of maintenance actions upon failure of the system. Types of maintenance actions considered are minimal repair and replacement. Minimal repair cost is assumed to be random, whereas replacement cost is fixed. A policy, B(t), which determines the type of maintenance action based on the estimated minimal repair cost when the system fails at time t is adopted. To obtain an optimal policy, an expected maintenance cost per unit time is derived and is minimized with respect to B(t).

• Journal of Digital Policy
• /
• v.1 no.1
• /
• pp.21-26
• /
• 2022

This Study will focus the fact that large portion of inpatient treatment cost might incurred in nursing hospital and consider whether policy of allowing inpatient treatment is appropriate or not. Finally This study will suggest alternative way to make improvement based on cases from other countries. This study use data published by Health Insurance Review & Assessment Service. & National Health Insurance Service which is very reliable. This Study found biggest medical spending in allowance of medical care is inpatient treatment cost and large portion of inpatient treatment cost might incurred in nursing hospital. This Study found policy of allowing patient to get inpatient treatment is not clearly determinded. Therefore patient who don't actullay need medical service enter and stay in nursing hospital. Their inpatient treatment cost is paid by allowance of medical care and this cost is unnescessary medical cost. This study suggest policy of allowing patient need to be clear. Government should mandate nursing hospital to check whether patient's condition is appropriate to enter and stay in nursing hospital. This study suggest way to reduce unnecessary inpatient treatment cost incurred in nursing hospital

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.24 no.62
• /
• pp.1-10
• /
• 2001

The electronics industry is fast growing segment of manufacturing and service industries. It is important that the manufacturer develops a product with adequate life cycle, high quality, and low failure rate in the specified time period. Environmental Stress Screening(ESS) and burn-in are widely used in the electronic industry to assist in the elimination of early failure. In this research, we construct optimal cost model of combined ESS and burn-in under various warranty policy and establish optimal testing times for given environments. Also we conduct sensitivity analysis on various parameter. The results of this study are summarized as follows. Comparing free warranty policy to rebate warranty policy, optimal ESS time is longer under free warranty policy, and optimal burn-in time is longer under rebate warranty policy. Free warranty policy higher than rebate warranty policy in total cost.

• Health Policy and Management
• /
• v.20 no.4
• /
• pp.45-57
• /
• 2010

Background : If different cost efficiency indexes were informed to the same clinic depending on the inclusion or exclusion of pharmacy cost, it may impair the reliability of provider-profiling system. This study aimed to investigate whether the omission of pharmacy cost affects cost-efficiency rankings in medical clinics. Methods : Data for ambulatory care cost at 23,112 medical clinics were collected from the claims database, which was constructed after review by the Health Insurance Review and Assessment Service (HIRA) of Korea in April 2007. We calculated two types of cost efficiency indexes by inclusion or exclusion of pharmacy cost for a medical clinic. The agreement between the decile rankings of the two indexes was also assessed using the weighted kappa statistic of Landis and Koch. Results : When the cost efficiency index for total cost including pharmacy cost was compared with the index for total cost excluding it, the agreement between the two indexes was only 55%. The agreements between the two indexes were relatively low within specialties which have larger pharmacy volume of total cost and lower correlation between total cost with or without pharmacy cost included than the average level of all the specialties. Conclusion : These results suggest that the omission of pharmacy cost may result in contradictory outcomes that may be confusing to a medical institution and may impair the reliability of provider-profiling systems. It is very important to standardize profiling criteria for the reliability of provider profiling system.

• Journal of Korean Society for Geospatial Information Science
• /
• v.11 no.4 s.27
• /
• pp.29-34
• /
• 2003

The purpose of this study is to present the price computation criteria with the aspect of price policy for the geographical information circulation. The price policy is to make activated circulation for geographical information. The price policy of this research considered the supplier and the user side at the same time. Important issue of price policy is that initial cost for system development calculate burying cost, and preservation and renewal cost charge to user. Distribution cost of geographical information charge to user according to use media, and apply differential rates of cost according to the purpose of using, up-to-dateness of data. Also, present the price policy that must apply copyright fee to of offer geographical information. Consider various terms that was studied in this study, the price computation criteria was presented. Through this, it is expected that geographical information circulation is activated more.

• Journal of Korean Institute of Industrial Engineers
• /
• v.36 no.2
• /
• pp.108-116
• /
• 2010

The maintenance of a deteriorating system is often imperfect. Previous studies have shown that the imperfect preventive maintenance (PM) can reduce the wear out and aging effects of deteriorating systems to a certain level between the conditions of as good as new and as bad as old. In this paper, we employ the concept of the improvement factor in investigating two optimal PM policies; failure limit policy and periodic PM policy. We redefine the improvement factor model as a function of the cost of PM, using this concept, we derive the conditions of optimal PM policies and formulate expressions to compute the expected cost rate. Based on this information, the determination of the maintenance policies which minimize the cost rate is examined. Numerical examples for the Weibull distribution case are also given.

• Journal of Korean Institute of Industrial Engineers
• /
• v.34 no.4
• /
• pp.425-432
• /
• 2008

While the Vendor-Managed Inventory(VMI) is a convenient inventory replenishment policy for the customer company, the supplier usually bears the burden of higher inventory and urgent shipments to avoid shortage. Recently some manufacturers begin to fix the production schedule for the next few days (such as three days). Utilizing that information can improve the efficiency of the VMI. In this study, we present a myopic optimization model using a mixed inter programming; and a heuristics algorithm. We compare the performance of the two proposed methods with the existing (s, S) reorder policy. We consider the total cost as the sum of transportation cost and inventory cost at the customer's site. Numerical tests indicate that the two proposed methods significantly reduce the total cost over the (s, S) policy.

• Journal of Korean Society for Quality Management
• /
• v.30 no.4
• /
• pp.94-105
• /
• 2002

In this paper, replacement problems for a deteriorating system are considered. In the system under consideration, the successive lifetimes after repair become shorter and shorter, while the consecutive repair times become longer and longer. More specifically, the lifetimes of the system form a nonhomogeneous Poisson process, whereas the consecutive repair times constitute a stochastically increasing geometric process. Optimal replacement policies for the long-run average cost rate and the steady state availability are considered. Also taking the cost and the availability into consideration at the same time, the properties of optimal policies under the Cost Priority Policy and the Availability Priority Policy are obtained.