• 제목/요약/키워드: unit cost

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유전자 알고리듬을 이용한(m,n)중-연속(r,s):고장 격자 시스템의 정비 모형 (A Maintenance Design of Connected-(r,s)-out-of-(m,n):F System Using Genetic Algorithm)

  • 윤원영;김귀래;정철훈
    • 대한산업공학회지
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    • 제30권3호
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    • pp.250-260
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    • 2004
  • This study considers a linear connected-(r,s)-out-of-(m,n):F lattice system whose components are ordered like the elements of a linear (m,n )-matrix. We assume that all components are in the state 1 (operating) or 0 (failed) and identical and s-independent. The system fails whenever at least one connected (r,s)-submatrix of failed components occurs. The purpose of this paper is to present an optimization scheme that aims at minimizing the expected cost per unit time. To find the optimal threshold of maintenance intervention, we use a genetic algorithm for the cost optimization procedure. The expected cost per unit time is obtained by Monte Carlo simulation. The sensitivity analysis to the different cost parameters has also been made.

연장된 보증이 있는 교체정책에 대한 베이지안 접근 (A Bayesian Approach to Replacement Policy with Extended Warranty)

  • 정기문
    • 한국신뢰성학회지:신뢰성응용연구
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    • 제13권4호
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    • pp.229-239
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    • 2013
  • This paper reports a manner to use a Bayesian approach to derive the optimal replacement policy. In order to produce a system with minimal repair warranty, a replacement model with the extended warranty is considered. Within the warranty period, the failed system is minimally repaired by the manufacturer at no cost to the end-user. The failure time is assumed to follow a Weibull distribution with unknown parameters. The expected cost rate per unit time, from the end-user's viewpoints, is induced by the Bayesian approach, and the optimal replacement policy to minimize the cost rate is proposed. Finally, a numerical example illustrating to derive the optimal replacement policy based on the Bayesian approach is described.

고차 발전 비용 함수를 고려한 새로운 경제급전 알고리즘 (A New Economic Dispatch Algorithm Considering Any Higher Order Generation Cost Functions)

  • 박정도;문영현
    • 대한전기학회논문지:전력기술부문A
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    • 제51권12호
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    • pp.603-610
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    • 2002
  • In this paper, a new economic dispatch algorithm for unit commitment is proposed to improve both the accuracy of the final solution and the calculation speed of economic dispatch. By using the inverse incremental cost functions, economic dispatch can be transformed into a simple optimization problem associated with an n-th order polynomial equation. The proposed method remarkably reduces the computation time with adaptability to any higher order generation cost functions. The proposed method is tested with sample system, which shows that the proposed algorithm yields more accurate and economical generation scheduling results with high computation speed.

Optimal Schedules of Periodic Preventive Maintenance Model with Different PM Effect

  • Lim, Jae-Hak
    • International Journal of Reliability and Applications
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    • 제9권1호
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    • pp.113-122
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    • 2008
  • In this paper, we consider a periodic preventive maintenance policy in which each preventive maintenance reduces the hazard rate of amount proportional to the failure intensity, which increases since the system started to operate. And the effect of preventive maintenance at each preventive maintenance epoch is different. The expected cost rate per unit time for the proposed model is obtained. We discuss the optimal number N of the periodic preventive maintenance and the optimal period x, which minimize the expected cost rate per unit time and obtain the optimal preventive maintenance schedule for given cost structures of the model. A numerical example is given for the purpose of illustrating our results when the failure time distribution is Weibull distribution.

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A Bayesian Approach to Replacement Policy Based on Cost and Downtime

  • Jung, Ki-Mun;Han, Sung-Sil
    • Journal of the Korean Data and Information Science Society
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    • 제17권3호
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    • pp.743-752
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    • 2006
  • This paper considers a Bayesian approach to replacement policy model with minimal repair. We use the criterion based on the expected cost and the expected downtime to determine the optimal replacement period. To do so, we obtain the expected cost rate per unit time and the expected downtime per unit time, respectively. When the failure time is Weibull distribution with uncertain parameters, a Bayesian approach is established to formally express and update the uncertain parameters for determining an optimal maintenance policy. Especially, the overall value function suggested by Jiagn and Ji(2002) is applied to obtain the optimal replacement period. The numerical examples are presented for illustrative purpose.

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종합병원의 비보험환자 처치행위 양상과 수가분석에 관한 연구 (An Analysis of Nursing Behavior and Unit of Treatment Cost of Non- Insurance Patients)

  • 오세영
    • 대한간호학회지
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    • 제10권1호
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    • pp.41-55
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    • 1980
  • The medical care insurance system, being put into practice nearly for three years, seem to have brought about some considerable problems as serious for the government as to consider a revision of that system. As one of the most serious problems of present system, the treatment cost of insurance patients is so remarkably low in comparison with than of non-insurance cases that normal operation of hospitals is threatened and care services of low quality are induced. The researcher carried out this survey to analyze and bring to light several aspects of treatment cost of non-insurance patients as a material for a re-assessment of the cost of insurance cases which shows a a considerable difference in amount at the standpoint of hospitals with than of non-insurance cases and further, hoping the significant blind spot of present insurance system(that is, the absence of regulations' for cost assessment by patterns or types of health care treatment) will be mended in near future. The survey was carried out with the treatment invoice sheets of total 902 in-hospital Patients of a general hospital in Seoul during the period of the 2 nd quarter of the year(1979). Among total 902 patients, 694 cases were used for analysis, because those disease or syndromes shared by less than 10% of the patients were put aside before procession. The data were analyzed by kinds or types of diseases, demographic characteristics of patients, hospitalization patterns, types of nursing treatment, etc. The result of analysis was as follows 1. Among all the non-insurance cases, those who received one or more kinds of nursing treatment mounted up to 96. 7 %. The invoice issue frequency per person was 7.2 times, while that frequency per day for a person was 0.8, : the treatment cosr per person was ₩22,650 while its daily average was ₩2,430, due to the average 9.3 in-hospital days per person. 2. As to the nursing treatment types by the demographic characteristics of patients and hospitalization patterns. a. The unit cost female patients was generally more expensive them that of males, and independent nursing service was more given than other types of treatment. As to age, higher age groups received independent nursing service most, while the youngest group received instrumental and integrated nursing services. b. As to room grade, the unit cost of I.C.U. cases was the highest : and the cast of private room patients was higher than that of public room patients. By in-hospital days, the curve of function showed L. type : that is, the longer stay, the lower function. 3. State of treatment types by kinds of disease were ; a. Dependent nursing service showed comparatively high availability in surgical and neurologic disease and independent nursing service was most received by medical, obstetrical and urological patients, while instrumental and integrated services were most available for respiratory disease and obstetrical and neurologic diseases next. b. The invoice issue frequency per day for a patient was highest in obstetrical disease 3.8 times, and the unit cost(per one invoice sheet) was also highest in obstertrical disease(₩10,880) and next in neurologic cases(₩ 4,690 ). 4. As to the pertained departments. a. Cost amount per person was highest in department of Psychiatries daily cost was highest in obstetrical cases : while the invoice issue frequency was highest in obstetrics and next in pediatrics. b. In departments in need of surgical operation, dependent nursing care was highly availabl : while in internal medicine and obstetrics, independent service was higher. Psychiatrics showed the highest the of integrate nursing while pediatrics and obstetrics higher of instrumental services. The variation co-efficien of treatment cost came out to be relatively in high in special surgery, opthalmology and internal medicine. 5. State of treatment cost by types of nursing behavior was. a. The average frequency of invoice issue was 3.5 (times). Among the type four types of treatment, instrumetal service (4.3) and independent nursing behavior(3.9) showed higher frequency than average respectively. But as to unit cost (per invoice). dependent (₩5,200) and integrated (₩5,340) nursing care services were higher than average and considerably higher than the other two types. b. In repect patient distribution. independent nursing behavior(80.3% ) was the highest and depend ent nursing (31.7% ) the lowest. The variation co-efficient of treatment cost appeared highest in dependent nursing be havior as a whole, and among that, doctor's diagnosis showed the highest coefficient value (100.7). In conclusion, the variaty of treatment cost(treatment itself ) by various characteristics and treatment types pro- that treatment various sort of patients and treatment cost of various types of nursing behavior cannot be uniform. Therefore, to attain the equalization of health care service and its cost both for insurant and non-insurant patients, a more specific provision for assessment of cost should be added to the present medical care insurance system and, in addition, the cost of nursing treatment is desired to be inserted into the treatment invoice.

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Optimal System Design of Consecutive-k-out-of-n:F System

  • Yun, Won-Young;Kim, Gui-Rae;Yamamoto, Hisashi
    • 한국품질경영학회:학술대회논문집
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    • 한국품질경영학회 2006년도 추계 학술대회
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    • pp.309-314
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    • 2006
  • The linear Consecutive-k-out-of-n:F system consists of n component ordered linearly and fail if and only if at least k consecutive components fail. We assume that the components are independent and identical exponentially distributed. This paper develops a model to calculate the expected cost per unit time of a linear consecutive-k-out-of-n:F system. The optimization problem we consider regards the choice of the system structure parameter k to minimized the expected cost per unit time.

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종속 고장을 가지는 원형 Consecutive-k-out-of-n:F 시스템의 경제적 설계

  • 윤원영;김귀래;고용석;류기열
    • 한국신뢰성학회:학술대회논문집
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    • 한국신뢰성학회 2000년도 추계학술대회
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    • pp.387-395
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    • 2000
  • Circular consecutive-k-out-of-n:F system when the failure of component is dependent is studied. We assume that the failure of a component in the system increase the failure rate of the survivor which is working just before the failed component. In this case, a mean time to failure (MTTF), a average failure number of the system, and the expected cost per unit time are obtained. Then the minimum number of consecutive failed components to cause system failure to minimize the expected cost per unit time is determined as searching paths to system failure. And various numerical examples are studied.

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Optimization of theM/M/1 Queue with Impatient Customers

  • Lee, Eui-Yong;Lim, Kyung-Eun
    • International Journal of Reliability and Applications
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    • 제3권4호
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    • pp.165-171
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    • 2002
  • An optimization of the M/M/1 queue with impatient customers is studied. The impatient customer does not enter the system if his or her virtual waiting time exceeds the threshold K > 0. After assigning three costs to the system, a cost proportional to the virtual waiting time, a penalty to each impatient customer, and also a penalty to each unit of the idle period of the server, we show that there exists a threshold K which minimizes the long-run average cost per unit time.

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계수선별형 샘플링검사의 경제성에 관한 연구 (A Study on the Economical Design of Sampling Inspection Method by Attribute)

  • 김진수;권혁윤
    • 산업경영시스템학회지
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    • 제20권41호
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    • pp.147-156
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    • 1997
  • This Study deals with the problem of determining a minimum cost sampling inspection plan for destructive testing by attribute. The linear cost model(LCM) is constructed under the assumption that unit cost, destructive testing cost, producer's risk cost, consumer's risk cost are given. For the solution from the LCM, we assumed the uniform distribution as a prior distribution.

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