• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.91-98
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• 2008

In digital broadcasting, it is possible to multiplex maximum one hundred audio or music programs into MPEG-2 transport stream, which is suitable for transmitting through one channel. In order to check if multiplex music programs are transmitted well, we need a multiplex audio monitoring system that monitors the programs in real-time. In analog broadcasting, we have used hardware-based audio monitoring system for a small number music programs. However, the effectiveness of hardware-based audio monitoring system from the cost and function viewpoint is so low that a new system is needed for digital broadcasting. In this paper, we have designed and implemented a software-based audio monitoring system to satisfy these requirements. In this implementation, only one PC is used without other hardware facilities, and the system monitors digital broadcasting music programs effectively. Transmitted digital broadcasting streams are demultiplexed into many music programs and the realtime value of audio level and packet error information for these programs are displayed in the screen. Thus, the system detects and shows the abnormal transmitting programs automatically. Simulation results show that effective realtime multiplex audio monitoring is possible for digital broadcasting music programs.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.53-59
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• 2021

The marine transport industry generally applies new technologies later than other transport industries, such as airways and railways. Vessels require efficient operation, and their performance and lifespan depend on the level of maintenance and management. Many studies have shown that corrective maintenance (CM) and time-based maintenance (TBM) have restrictions with respect to enabling efficient maintenance of workload and cost to improve operational efficiency. Predictive maintenance (PdM) is an advanced technology that allows monitoring the condition and performance of a target machine to predict its time of failure and helps maintain the key machinery in optimal working conditions at all times. This study presents the development of a marine predictive maintenance (MPdM; maritime predictive maintenance) method based on applying PdM to the marine environment. The MPdM scheme is designed by considering the special environment of the marine transport industry and the extreme marine conditions. Further, results of the study elaborates upon the concept of MPdM and its necessity to advancing marine transportation in the future.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.416-416
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• 2016

Organic-inorganic metal halide perovskite solar cells have received attention because it has a number of advantages with excellent light harvesting, high carrier mobility, and facile solution processability and also recorded recently power conversion efficiency (PCEs) of over 20%. The major issue on perovskite solar cells have been reached the limit of small area laboratory scale devices produced using fabrication techniques such as spin coating and physical vapor deposition which are incompatible with low-cost and large area fabrication of perovskite solar cells using printing and coating techniques. To solution these problems, we have investigated the feasibility of achieving fully printable perovskite solar cells by the blade-coating technique. The blade-coating fabrication has been widely used to fabricate organic solar cells (OSCs) and is proven to be a simple, environment-friendly, and low-cost method for the solution-processed photovoltaic. Moreover, the film morphology control in the blade-coating method is much easier than the spray coating and roll-to-roll printing; high-quality photoactive layers with controllable thickness can be performed by using a precisely polished blade with low surface roughness and coating gap control between blade and coating substrate[1]. In order to fabricate perovskite devices with good efficiency, one of the main factors in printed electronic processing is the fabrication of thin films with controlled morphology, high surface coverage and minimum pinholes for high performance, printed thin film perovskite solar cells. Charge dissociation efficiency, charge transport and diffusion length of charge species are dependent on the crystallinity of the film [2]. We fabricated the printed perovskite solar cells with large area and flexible by the bar-coating. The morphology of printed film could be closely related with the condition of the bar-coating technique such as coating speed, concentration and amount of solution, drying condition, and suitable film thickness was also studied by using the optical analysis with SEM. Electrical performance of printed devices is gives hysteresis and efficiency distribution.

• Journal of Korean Society of Transportation
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• v.26 no.1
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• pp.65-78
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• 2008

After the railway reform in 2004, Korea National Railroad was divided into two separate organizations. The Korea Railway Network Authority is responsible for the construction of new line. Korea Railroad corporation is a public-owned railway operator. The compensation for the loss of rail operator from the Public Service Obligation(PSO) observance is specified in the Law of Rail Industry Development No.32, No.33. However, it is necessary to revise the compensation criteria of PSO after the actual enforcement of the law for more efficient rail operation. This study aims for revising compensation criteria of PSO. In this study, we suggested a revised compensation criteria. The scope of compensation for the loss of regional line operation was adjusted by new criteria considering the characteristics and the business results of the line. The compensation rate is linked with the actual business results of the line for giving motivation to the rail operator.

• Journal of Korean Society of Transportation
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• v.17 no.5
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• pp.43-55
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• 1999

The value of time in freight transportation describes the importance of goods during transport and shows the direction of efficient logistic management having inventory cost in transporting The value of time differs from class to class in freight transportation. It is due to the differences of shipper's willingness to Pay for time saving. In this research the value of time in intercity freight transportation of manufacturers in Korea was estimated as follows: first, the Perception factors which were the important criteria of shippers for choosing truck were sampled. second, the shippers were classified into three homogeneous classes. third, the value of time of each class was estimated by using multinominal logit model. The results of this research showed that the value of time in freight transportation was different from every class, that the shipper had to Pay 1,680 won for saving one hour Per each shipment, and that the inventory cost in transporting occupied 9.54% in the mean freight Price.

• Journal of the Korean Operations Research and Management Science Society
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• v.1 no.1
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• pp.111-125
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• 1976

This study investigates the one-year performance of the Seoul Metropolitan Rail Transit(SMRT) operation. It intends to provide a basic understanding for railway operation in Seoul Metropolitan Area and thereby for making rational transport policy. The paper is conceptually comprised of four sections; analysis of passenger travel characteristics; SMRT costing and traffic cost function: its operating characteristics in terms of finance and utilization; primary social benefits of SMRT and suggestions. In the first year of operation (1974), the average daily traffic was about 335,000, After the drastic increases of fare in both Subway and KNR rail-lines, the travel volume has been cut by almost 10 percent, though most pronounced on intra-Subway line. The spatial distribution of passengers indicates that travelers use the SMRT line mainly for uninterrupted direct travel toward the CBD. In the prospective costing, the opereting expenses are divided into three groups; those which vary directly with volume; those partially variable with volume; and those entirely unrelated to volume change, With this information, cost function was derived for varying schedules of operation. Primary social benefits of the SMRT are assessed, though preliminary. Account should be taken of the nature of common costs of the SMRT in fare-rate making, especially when much of the operating expenses are accounted for by the fixed costs such that the revenue may not readily turn into break-even. The accounting results of the one-year operation coincide reasonably well with the prospective costing estimates. According to the findings of this annd another travelers' behavior studies, managerial effort would bring more revenue gain to the SMRT than fare increase does, not to speak of greater social benefits by so doing.

• Korean Management Science Review
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• v.19 no.2
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• pp.221-235
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• 2002

Many people are getting more and more interested in the value of information sharing in a supply chain in proportion to the development of information technology in these days. In spite of much interest in the value of shared information, the related studies concluded that the effect of only sharing information strategy between upper and lower level is not large However, many related companies want to link each channel members in the supply chain with on-line to expect to reduce the cost by means of information sharing. This study wants to evaluate the alternative strategy to reduce more related costs than only sharing information strategy. This paper analyzed that how much the total supply chain cost is to change in the case of a transfer of decision rights from the lower (retailers) to the upper level (depot, vendor) in a supply chain. The decision rights mean the rights of being able to decide when to order, how much to order, where to order, and what mode to transport or distribute, etc. in a supply chain. By the experimental simulation study to the simple case, the strategy to share only information took the low effect of 1～2%, but the strategy to transfer the decision lights from the lower to the upper member had larger effect of about 5%. However. for the strategies to work well, it needs to cooperate closely among each supply chain members, and the fruits from the transfer of decision rights in a supply chain are allocated to each chain members reasonably Therefore, there needs to study in the future not only the exact transfer effect of decision rights, but the reasonable allocation method of the fruits among the chain members.

• Journal of Korea Port Economic Association
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• v.33 no.1
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• pp.89-110
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• 2017

The organization of the shipping conference -an international cartel, was approved by countries that recognized it for stabilizing routes as well as preventing excessive competition among liner shipping companies and recognized the characteristic of the liner service that is regularly repeated in the international liner shipping market. However, due to competition in bulk transportation and development of multimodal transport through new entrants, power expansion and vessel enlargement of non-aligned shipping companies; the shipping conference started collapsing, and was eventually abolished. As the shipping conference played an important role in the liner shipping market, there were changes in the competition structure of the liner shipping market, and this accordingly drove research on the effects of the abolition of the shipping conference on the liner shipping market. The effects of abolition of the shipping conference on the liner shipping market was analyzed after surveying the factors related to abolition of the shipping conference, and through the use of correlation and multiple regression analyses. Subsequent to the abolition of the shipping conference, the liner shipping companies increased global containership bottoms. Consequently, this led to fierce competition of freight charges. As a result, profitability of shipping companies diminished. However, shipping companies with a dominating cost structure recorded profits, while shipping companies with an inferior cost structure started recording a loss.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.3
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• pp.529-534
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• 2016

The paper suggests risk management methodology for alleviating casuality accidents at urban railway stations. Risk management deals with countermeasures for reducing accident probability or consequences to reach at the certain level of risk. First of all, Economic evaluations using cost and benefit for all the alternatives are performed. The alternatives exceeding B/C ratio greater than 1, each alternative is applied in the order of higher B/C ratio. this process is repeated when the level of risk is reduced as low as reasonably practical (ALARP). In order to determine the level of ALARP, Level of Service (LOS) for casuality risk at urban railway stations is proposed. The ALARP level is set to the LOS "C". Finally, a case study is applied to the Jongno 3-ga station, which is a highest risky station among all the stations operated by Seoul Metro and Seoul Metropolitan Rapid Transit Cooperation (SMRT).

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.614-620
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• 2003

KAERI has developed DUPIC nuclear fuel with the refabrication of spent PWR fuel discharged from domestic nuclear power plant by a dry process at M6 hot-cell in IMEF To verify the performance of DUPIC nuclear fuel, irradiation test at the operating conditions of commercial power plant is essential. Since the HANARO research reactor of KAERI does not have fuel test loop(FTL) for irradiating nuclear fuel under high temperature and high pressure conditions, DUPIC fuel cannot be irradiated in the FTL of HANARO. In the 13-th PRM among Korea, Canada, USA and IAEA, AECL proposed that KAERI fabricated DUPIC fuel can be irradiated in the FTL of the NRU research reactor without charge of neutrons. The transportation quantity of DUPIC fuel to Canada is 10 elements(about 6kg). This transportation package is classified as the 7-th class according to "recommendation on the transport of dangerous goods" made by the United Nations. In case of air shipment, until now, there is no proper air transportation cask for DUPIC fuel. In case of sea transportation is possible but requires very high cost.high cost.