• Smart Structures and Systems
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• 제30권6호
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• pp.571-582
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• 2022

Optimal life-cycle management is a challenging issue for deteriorating regional bridges. Due to the complexity of regional bridge structural conditions and a large number of inspection and maintenance actions, decision-makers generally choose traditional passive management strategies. They are less efficiency and cost-effectiveness. This paper suggests a deep reinforcement learning framework employing double-deep Q-networks (DDQNs) to improve the life-cycle management of deteriorating regional bridges to tackle these problems. It could produce optimal maintenance plans considering restrictions to maximize maintenance cost-effectiveness to the greatest extent possible. DDQNs method could handle the problem of the overestimation of Q-values in the Nature DQNs. This study also identifies regional bridge deterioration characteristics and the consequence of scheduled maintenance from years of inspection data. To validate the proposed method, a case study containing hundreds of bridges is used to develop optimal life-cycle management strategies. The optimization solutions recommend fewer replacement actions and prefer preventative repair actions when bridges are damaged or are expected to be damaged. By employing the optimal life-cycle regional maintenance strategies, the conditions of bridges can be controlled to a good level. Compared to the nature DQNs, DDQNs offer an optimized scheme containing fewer low-condition bridges and a more costeffective life-cycle management plan.

• Asian-Australasian Journal of Animal Sciences
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• 제17권11호
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• pp.1586-1590
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• 2004

An experiment was carried out with day-old "Sonali" (♂RIR$\times$♀Fayoumi) chicks to investigate the efficacy of locally made low cost brooders for brooding chicks in rural areas. Three types of indigenous brooders viz. charcoal, haricane and sawdust brooders were used for brooding chicks throughout the experimental period of 28 days. The efficiency of the brooders was observed in respect of their ability to maintain temperature, fluctuation in temperature during operation and cost effectiveness. Following initial trial of temperature maintenance for 48 h, the chicks were put under the brooder stoves and brooded up to 28 days. The experimental birds were fed on chick starter diet. Maintenance of temperature with sawdust brooders was found satisfactory and optimum for brooding the chicks at different stages of brooding and at the same time involved least cost for brooding in comparison with charcoal and haricane brooders which did not perform well in generating heat necessary for brooding and were not economically feasible for poor farmers. On the other hand, performance of charcoal brooders was better in respect of temperature maintenance during initial stage (when the brooder was started) but the temperature fluctuated rapidly, whereas fluctuation of temperature was gradual in sawdust brooders. Body weight gain and feed conversion were best in sawdust brooders. Survivability was highest in sawdust brooders and lowest in haricane brooders. Sawdust brooders may be appropriate for brooding chicks in rural areas, where electricity is not available.

• 산업경영시스템학회지
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• 제43권3호
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• pp.41-52
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• 2020

This paper investigates the stress-reducing preventive maintenance model through numerical experiments. The preventive maintenance model is used to analyze the relationship between related conditions and variables to gain insight into the efficient operation of the system when performing preventive maintenance in real-world situations. Various preventive maintenance models have been developed over the past decades and their complexity has increased in recent years. Increasing complexity is essential to reflect reality, but recent models can only be interpreted through numerical experiments. The stress-reducing preventive maintenance is a newly introduced preventive maintenance concept and can only be interpreted numerically due to its complexity, and has received little attention because the concept is unfamiliar. Therefore, for information purposes, this paper investigates the characteristics of the stress-reducing preventive maintenance and the relationship between parameters and variables through numerical experiments. In particular, this paper is focusing on the economic feasibility of stress-reducing preventive maintenance by observing changes in the optimal preventive maintenance period in response to changes in environmental stress and the improvement factor. As a result, when either the environmental stress or the improve effect of stress-reducing preventive maintenance is low, it is not necessary to carry out the stress-reducing preventive maintenance at excessive cost. In addition, it was found that the age reduction model is more economical than the failure rate reduction model.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.177-183
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• 2009

This paper deals with the topical problems of the Life Cycle Costs in connection with the rolling stocks. the LCC philosophy has already entered the third decade. this philosophy contributed towards the new relationship's comprehension between railway vehicle producers' and railway vehicle users' sphere. this leads together to the technical-economical solution convenient for the both sides. In the point of manufacturer, It is said that low operational costs could be reached using a well-designed and structured maintenance program. this is due to the proper technical analysis of critical components that leads to low costs of maintenance and a superior reliability without increasing the capital investment. but, This paper presents both topical experiences with the LCC models for the railways vehicles and also procedures during Life Cycle Costs calculations. In conclusion I want to introduce how to calculate LCC & what kinds of softwares are used based on VVVF EMU vehicle

• Industrial Engineering and Management Systems
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• 제3권1호
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• pp.59-62
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• 2004

The number of tunnel has fast increased with the rapid expansion of highway network. Tunnel should be designed to provide for drivers both safety and pleasant driving conditions. In this perspective, the design for tunnel lightning is very important in order to provide its safety, pleasantness, and cost-efficiency of maintenance, all of which should be considered and analyzed for a better tunnel lighting. This paper attempts to compare the low-pressure sodium lamp, which have usually been used for tunnel lighting, with the fluorescent lamp, which we consider as an alternative for the former. In an effort to determine the number of lamps to meet the required illuminance in the tunnel, this research employs a simulation technique which would allow us to conjecture, with the aid of basic model, the life cycle cost for illumination per each tunnel. This analysis is expected to provide a basic method and related information for tunnel development and design.

• 한국건축시공학회지
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• 제12권4호
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• pp.386-392
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• 2012

In this study, life cycle cost (LCC) is analyzed according to insulation panel system type using a deterministic LCC analysis method. Through this analysis, it was found that the construction cost in the deterministic LCC analysis for Ceramic panels was low compared to the construction cost for metal and stone panels. Also, the difference in cost between the Ceramic panel and the metal panel was about 2 times. In the area of maintenance cost, it was found to be similar to the previously analyzed construction cost, in which the metal panel has the highest cost due to the high cost of construction and the frequent need for maintenance. In the case of the stone panel, a small difference in cost is shown compared with that of the Ceramic panel, but the cost is higher than the Ceramic panel. Regarding the cost of waste disposal, the Ceramic panel can reduce the cost by at least 1.5 times and up to 2 times compared to other panel systems. Finally, in the analysis of sensitivity according to changes in discount rates, the Ceramic panel and metal panel systems have a similar cost, and the cost of the metal panel is a bit larger than that of other panel systems. Thus, in the subjects used in the analysis, the Ceramic panel system shows the highest economic benefits.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1269-1274
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• 2011

To cut down the maintenance expenses at branch lines, the foreign developed countries have developed the low-cost signalling on low-density lines. These examples are FFB(FunkFahrBetrieb) Radio based train operation by German railways(Deutsche Bahn AG), ERTMS REGIONAL by Europe and LOCOPROL system using a GPS. Also, Korea is developing Information and Communication Technology based low-cost signalling on low-density lines. The characteristics of this system are directly controled switch and crossing by driver. For the purpose of this paper, we reviewed the business process for switch and crossing control. Specially, we compared and analysed both methods whether the driver takes control over the operation procedures of switch or the control message is carried by the command of the controller. And by utilizing the instrument of UML, I planned the switch according to the control authority and the operation procedures needed for the control of crossing.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.854-861
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• 2004

LRT(Light Rail Transit System) is devided into steel-wheel train, LIM and rubber tired AGT(Automated Guide-way Transit System) The main features of LRT are low construction cost, low space, low noise, Environment-friendly, fastly, low maintenance cost. it's a civil transit transfer system of new generation became popular advanced nation. In this study, the beginning designed manufactureing rubber tired AGT turnout and guide-way system for the field application. We hope reliability for the system shall home production of turnout and guide-way

• 유통과학연구
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• 제11권12호
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• pp.39-49
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• 2013

Purpose - This study attempts to examine the underlying dimensions of service quality (tangibility, reliability, responsiveness, assurance, and empathy) for low-cost carriers. It subsequently seeks to determine the effect of the relationships of the dimensions of service quality, airline image, and behavioral intentions on airline services to provide adequate basic information and attributes for developing differentiated and competitive service marketing strategies. Research design, data, and methodology - The survey for this study was conducted on patrons with low-cost carrier boarding experiences in districts near universities and central businesses of Seoul and Busan from 5/10/2012 to 16/10/2012. Out of 346 questionnaires, 20 questionnaires with missing data and insincere answers were excluded for this study. Collected data were processed using SPSS 18.0, and the hypothesis was verified by analyzing the structural equation model with Lisrel 8.54. First, the frequency analysis was conducted to identify universal characteristics. Second, the exploratory factor analysis and reliability analysis were conducted to identify the accuracy of the variable measurements of the construct. Third, to assess uni-dimensionality and reliability, confirmatory factor analysis was conducted. Finally, to verify the adequacy of the research model and research hypothesis, the structural model was employed. Results - The results revealed that the factors, "tangibility, reliability, responsiveness, assurance, and empathy" were shown to be the most important dimensions of service quality for the airline image of the low-cost carrier which was consistent with previous studies. Therefore, it is fair to suggest that these verified factors are crucial attributes for the brand image of low-cost carriers. Second, as reliability and responsiveness were shown to be the most important factors for behavioral intentions, it is viable to suggest that these two attributes are crucial for the sales value of low-cost carriers. Further, it was found that the brand image of low-cost carriers was closely related to behavioral intentions. Therefore, in order to ensure the competitiveness and loyalty of patrons, the airline image value is a crucial attribute. Conclusions - The result of this study established that service quality is the most important attribute for marketing to ensure competitiveness, and intensive and differentiated service marketing play a crucial role in creating profits for low-cost carrier companies. First, as tangibility is found to be the most crucial factor in ensuring service quality, quality control and maintenance of medium and small carriers must be provided to ensure reliability, as they are the main attributes of low-cost carriers. Second, in order to promote positive behavioral intentions, it is essential to enhance the value of airline image. Third, in order to ensure competitiveness, it is imperative to carry out intensive and differentiated service marketing. Therefore, to promote the image of low-cost carriers and enhance behavioral intentions, the level of service quality must be secured by developing appropriate service improvement programs.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2010년도 춘계학술대회
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• pp.219-230
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• 2010

Remarkably improvements have occurred recently in the maintenance management of physical assets and productive systems, so that less wastages of energy and resources occur. The technology of maintenance is about finding and applying cost-effective ways of avoiding or overcoming performance deterioration. Maintenance is thus a vital support function in business, especially as increasingly large investments are being required in physical assets. TPM(Total Productive Maintenance) focuses on optimizing planning scheduling. Availability, performance and quality rate are other factors that affect productivity. Especially there are some losses that affect the overall equipment effectiveness(OEE). These losses lead to low values of OEE, which provides an indication of how effective the production precess is. This study explores the ways in which Korean small and medium manufacturing industries can improve OEE.