• The Journal of Korean Physical Therapy
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• v.25 no.2
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• pp.43-48
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• 2013

Purpose: The aim of this study was to demonstrate that non-participation of physical therapists on the political decision-making committee results in invasion of their interests. Methods: To demonstrate the effects, we analyzed the change of medical insurance score decided by the Health Insurance Policy Deliberation Committee between 2001 and 2012 years, focusing on medical examination as the interest of the participation group and physical therapy cost as interest of the non-participation group. Results: Total medical insurance cost increased by 23.72%, on average. Medical examination cost increased by 23.90% and 37.66% in medical examination for new and established patients, respectively. However, physical therapy cost was reduced by 5.01%. The medical examination cost for physical therapy without medical checkup increased by 2.62%. Conclusion: This study shows that the physical therapy cost, related on the interest of the non-participative group in the Health Insurance Policy Deliberation Committee, rather decreased while the total medical insurance cost increased.These findings demonstrate the invasion of the non-participative group on the Health Insurance Policy Deliberation Committee. Thus, aggressive participation in political decision-making committee is necessary in order to protect and increase rights and interests of Korean physical therapists.

• Journal of the military operations research society of Korea
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• v.25 no.2
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• pp.144-157
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• 1999

In this paper, we consider a new preventive replacement policy for the system which deteriorates while it is in operation with an increasing failure rate. The system is subject to two types of failure. A type 1 failure is repairable while a type 2 failure is not repairable. In the new policy, a system is replaced at the age of $t_p$ or at the instant the$\textsc{k}^{th}$ type 1 failure occurs, whichever comes first. However, if a type 2 failure occurs before a preventive replacement is performed, a failure replacement should be made. We assume that a type 1 failure can be rectified with a minimal repair. We also assume that a replacement takes a non-negligible amount of time while a minimal repair takes a negligible amount of time. Under a cost structure which includes a preventive replacement cost, a failure replacement cost and a minimal repair cost, we develop a model to find the optimal ($\textsc{k},t_p$) policy which minimizes the expected cost per unit time in the long run while satisfying a system availability constraint.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.18 no.34
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• pp.139-146
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• 1995

This study is concerned with cost analysis in periodic maintenance policy. Generally periodic maintenance policy in which item is repaired periodic interval times. And in the article minimal repair is considered. Minimal repair means that if a unit fails, unit is instantaneously restored to same hazard rate curve as before failure. In the paper periodic maintenance policy with minimal repair is as follows; Operating unit is periodically replaced in periodic maintenance time, if a failure occurs between minimal repair and periodic maintenance time, unit is replaced by a spate until the periodic time comes. Also unit undergoes minimal repair at failures in minimal-repair-for-failure interval. Then total expected cost per unit time is calculated according to maintenance period and scale parameter of failure distribution. Total cost factors ate included operating, fixed, minimal repair, periodic maintenance and replacement cost Numerical example is shown in which failure time of system has erlang distribution.

• Journal of the Korean Operations Research and Management Science Society
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• v.16 no.1
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• pp.135-146
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• 1991

This paper shows the infinite horizon model of Partially Observable Markov Decision Process with lagged information. The lagged information is uncertain delayed observation of the process under control. Even though the optimal policy of the model exists, finding the optimal policy is very time consuming. Thus, the aim of this study is to find an .eplison.-optimal stationary policy minimizing the expected discounted total cost of the model. .EPSILON.- optimal policy is found by using a modified version of the well known policy iteration algorithm. The modification focuses to the value determination routine of the algorithm. Some properties of the approximation functions for the expected discounted cost of a stationary policy are presented. The expected discounted cost of a stationary policy is approximated based on these properties. A numerical example is also shown.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.280-286
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• 2016

Purpose: Recently, Jiang defines the tradeoff B life to minimize a sum of life lost by preventive maintenance (PM) and corrective maintenance (CM) contribution parts and sets up an optimal replacement age of age replacement policy as this tradeoff life. In this paper, Jiang's model only considering the known lifetime distribution is extended by assigning different weights to two parts of PM and CM in order to reflect the practical maintenance situations in application. Methods: The new age replacement model is formulated and the meaning of a weight factor is expressed with the implied cost of failure under asymptotic expected cost model and also discussed with one-cycle expected cost criterion. Results: The proposed model is applied to Weibull and lognormal lifetime distributions and optimum PM replacement ages are derived with corresponding implied cost of failure. Conclusion: The new age replacement policy to escape the estimation of cost of failure in classical asymptotic expected cost criterion based on the renewal process is provided.

• Journal of the Korean Operations Research and Management Science Society
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• v.17 no.3
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• pp.27-46
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• 1992

This paper considers an (r, Q) policy for operation of a multipurpose facility. It is assumed that whenever the inventory level falls below r, the model starts to produce the fixed amount of Q. The facility can be utilized for extra production during idle periods, that is, when the inventory level is still greater than r right after a main production operation is terminated or an extra production operation is finished. But, whenever the facility is in operation for an extra production, the operation can not be terminated for the main production even though the inventory level falls below r. In the model, the demand for the product is assumed to arrive according to a compound Poisson process and the processing time required to produce a product is assumed to follow an arbitary distribution. Similarly, the orders for the extra production is assumed to accur in a Poisson process are the extra production processing time is assumed to follow an arbitrary distribution. It is further assumed that unsatisfied demands are backordered and the expected comulative amount of demands is less than that of production during each production period. Under a cost structure which includes a setup/ production cost, a linear holding cost, a linear backorder cost, a linear extra production lost sale cost, and a linear extra production profit, an expression for the expected cost per unit time for a given (r, Q) policy is obtained, and using a convex property of the cost function, a procedure to find the optimal (r, Q) policy is presented.

• Journal of Korea Planning Association
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• v.54 no.3
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• pp.27-48
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• 2019

The government has implemented housing welfare policy to ease low-income households' housing-cost burden and improve their quality of life. However, public housing residents and housing choice voucher recipients still show a high level of housing-cost burden. In this regard, this study aims to provide policy implications for current housing welfare policy by analyzing and comparing the factors that determine both subsidized and unsubsidized households' housing-cost burden. For the empirical analysis, this study uses "2017 Korea Housing Survey" and divides groups into public housing residents, housing choice voucher recipients, and unsubsidized low-income renters. We compared the level of housing-cost burden by employing t-test and chi-squared analyses and the factors affecting the housing-cost burden by employing logistic regression analyses between the three groups. According to the empirical analysis, the housing cost is the most burdensome for the housing choice voucher recipients group, followed by the unsubsidized low-income renters and public housing residents. In addition, the factors affecting housing-cost burden are different between the three groups. In case of public housing residents, housing characteristics usually affect the housing-cost burden. For housing choice voucher recipients and unsubsidized low-income renters, both housing and household characteristics influence the housing-cost burden. Looking at the detailed factors, except for the housing tenure and regional average rents that are common factors for all groups, the amount of deposit is an important factor for public housing residents, and household employment status is an important factor for both housing choice voucher recipients and unsubsidized low-income renters. The policy implications of this study are as follows: First, it is necessary to review the blind spot of the current housing welfare policy. Second, a comprehensive review of the housing choice voucher program is required. Third, it is necessary to make policy efforts to ease the level of housing-cost burden for renters. Fourth, a program is needed for those public housing residents who need a deposit support. Fifth, there should be further assistance with public housing for the poorest people.

• Journal of Navigation and Port Research
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• v.34 no.2
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• pp.131-136
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• 2010

The aim of the paper is to solve the problem of customer reduction due to the difficulty of parts sourcing which impacts production delay and delivery delay in SC networks. Furthermore, this paper is to suggest the new inventory policy of MTS in order to solve the problem of current inventory policy. In order to compare two policies, a LCD maker is selected as a case study and the real data for 2007 years is used for simulation input. The maker uses MTO policy for parts sourcing which has the problem of lead time even if it has some advantage of inventory cost. Based on current process. The simulation program of AS-IS model and TO-BE model using ARENA 10 version is developed for evaluation. In a result, the order number of two policies shows that MTO is 52 and MTS is 53. However the quantity of order shows big difference such that MTO is 168,460 and MTS is 225,106. Particularly, the lead time of new inventory policy shows much shorter that that of MTO such that MTO 100 is days and MTS is 16 days. In spite of short lead time by MTS policy, new policy has to take burden of inventory cost per year. Total inventory cost per year by MTS policy is US$ 11,254 and each part inventory cost is that POL is US$ 1,807, LDI is US$ 2,166 and Panel is US$ 7,281. The implication of the research is that the company has to consider the cost and the service simultaneously in deciding the inventory policy. In the paper, even if the optimal point of deciding is put into tactical area, the ground of decision is suggested in order to improve the problem in SC networks.

• Health Policy and Management
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• v.22 no.1
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• pp.145-162
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• 2012

The purpose of this study is to understand magnitude and its related factors of user's cost-sharing for non-covered services in long-term care facilities. We corrected data for 1,016 subjects, based on the long-term care benefits cost specification. Eighteen subjects were excluded from the data analysis due to missing data on family care-givers characteristics. Finally, 998 subjects were included in the study. The average cost of non-covered services per month was 209,093 won and distributed from 0 to 1,011,490 won. There was a significant difference by the characteristics of family care-givers and long-term care facilities. The monthly average cost for meal materials per person was 199,181 won(0~558,000), average cost of additional charge caused by using private bed was 232,992 won (50,000~600,000), and costs for haircut and cosmetics were 8,599 won. For the rest, there were various programs costs(93,328 won), diaper and its disposal cost(109,628 won), purchase cost for daily necessaries(24,435 won) and etc. The related factors for the magnitude of non-covered services expenditures were education level of family care-givers, occupancy rate and location of LTC facilities, and the costs of using private bed, haircut and cosmetics, and various programs among non-covered services. These findings suggest that present level range of LTC facilities users' cost-sharing is wide and it is urgent to prepare the standard guideline for cost and level in non-covered services.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.96-104
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• 2017

A one-shot system (device) refers to a system that is stored for a long period of time and is then disposed of after a single mission because it is accompanied by a chemical reaction or physical destruction when it operates, such as shells, munitions in a defense weapon system and automobile airbags. Because these systems are primarily related with safety and life, it is required to maintain a high level of storage reliability. Storage reliability is the probability that the system will operate at a particular point in time after storage. Since the stored one-shot system can be confirmed only through inspection, periodic inspection and maintenance should be performed to maintain a high level of storage reliability. Since the one-shot system is characterized by a large loss in the event of a failure, it is necessary to determine an appropriate inspection period to maintain the storage reliability above the reliability goal. In this study, we propose an optimal inspection policy that minimizes the total cost while exceeding the reliability goal that the storage reliability is set in advance for the one-shot system in which periodic inspections are performed. We assume that the failure time is the Weibull distribution. And the cost model is presented considering the existing storage reliability model by Martinez and Kim et al. The cost components to be included in the cost model are the cost of inspection $c_1$, the cost of loss per unit time between failure and detection $c_2$, the cost of minimum repair of the detected breakdown of units $c_3$, and the overhaul cost $c_4$ of $R_s{\leq}R_g$. And in this paper, we will determine the optimal inspection policy to find the inspection period and number of tests that minimize the expected cost per unit time from the finite lifetime to the overhaul. Compare them through numerical examples.