• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1481-1498
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• 2007

As railroad industry face the new Renaissance era, effective and efficient maintenance methods for rolling stock operation are required with advanced railroad technology. All kinds of railroad systems such as high speed long distance train, metropolitan mass transit and light rail require systematic maintenance technology in order to maintain the safe railroad operation. Simulation models for detailed operations of the sample maintenance center are developed. In this study, standard maintenance procedures, layout, equipments and number of workers of Siheung Metropolitan Railroad Maintenance Rolling Stock Depot are considered. The proposed simulation models are developed using simulation package ARENA. Three simulation analysis using the developed simulation model are done. First, the bottleneck operation is identified. Second, the relationship between maintenance center size, number of workers and cycle time is analyzed. Lastly, the scheduling performances between PERT/CPM and Critical Chain Project Management(CCPM) are compared.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.30B no.11
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• pp.1-10
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• 1993

This paper proposes a High Performance Full-Swing BiCMOS (HiF-BiCMOS) circuit which improves on the conventional BiCMOS circuit. The HiF-BiCMOS circuit has all the merits of the conventional BiCMOS circuit and can realize full-swing logic operation. Especially, the speed of full-swing logic operation is much faster than that of conventional full-swing BiCMOS circuit. And the number of transistors added in the HiF-BiCMOS for full-swing logic operation is constant regardless of the number of logic gate inputs. The HiF-BiCMOS circui has high stability to variation of environment factors such as temperature. Also, it has a preamorphized Si layer was changed into the perfect crystal Si after the RTA. Remarkable scalability for power supply voltage according to the development of VLSI technology. The power dissipation of HiF-BiCMOS is very small and hardly increases about a large fanout. Though the Spice simulation, the validity of the proposed circuit design is proved.

• KIEE International Transactions on Power Engineering
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• v.5A no.1
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• pp.9-15
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• 2005

In the operation of distribution systems, DGs (Distributed Generations) are installed as an alternative to extension and the establishment of substations, transmission and distribution lines according to the increasing power demand. In the operation planning of DGs, determining optimal capacity and allocation achieves economical profitability and improves the reliability of power distribution systems. This paper proposes a determining method for the optimal number, size and allocation of DGs in order to minimize the operation costs of distribution systems. Capacity and allocation of DGs for economical operation planning duration are determined to minimize total cost composed with power buying cost, operation cost of DGs, loss cost and outage cost using the GA (Genetic Algorithm).

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2002.11a
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• pp.296-303
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• 2002

The main subject to become a hub port is automation. The automated container terminal has already operated in advanced ports and it has been planned for the basic planning and operation design in domestic case. The key of automated container terminal is effective operation of both ATC(automated transfer crane) and AGV(automated guided vehicle) which is automated handling equipments. This is essential to poductivity of automated container terminal. This study suggests the most optimal method of equipment operation in order to minimize loading time using each three types of effective ATC operation methods and AGV dispatching rules in automated container terminals. As the automated equipment operation causes unexpected deadlocks or interferences, it should be proceeded on event-based real time. Therefore we propose the most effective ATC operation methods and AGV dispatching rules in this paper. The various states occurred in real automated container terminals are simulated to evaluate these methods. This experiment will show the most robust automated equipment operation method on various parameters(the degree of yard re-marshaling, the number of containers and the number of AGVs)

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.296-303
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• 2002

The main subject to become a hub port is automation. The automated container terminal has already operated in advanced ports and it has been planned for the basic planning and operation design in domestic case. The key of automated container terminal is effective operation of both ATC(automated transfer crane) and AGV(automated guided vehicle) which is automated handling equipments. This is essential to productivity of automated container terminal. This study suggests the most optimal method of equipment operation in order to minimize loading time using each three types or effective ATC operation methods and AGV dispatching rules in automated container terminals. As the automated equipment operation causes unexpected deadlocks or interferences, it should be proceeded on event-based real time. Therefore we propose the most effective ATC operation methods and AGV dispatching rules in this paper. The various states occurred in real automated container terminals are simulated to evaluate these methods. This experiment will show the most robust automated equipment operation method on various parameters(the degree of yard re-marshaling, the number of containers and the number of AGVs)

• Industrial Engineering and Management Systems
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• v.15 no.2
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• pp.131-142
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• 2016

We consider a multi-server queueing system without buffer and with two types of customers as a model of operation of a mobile network cell. Customers arrive at the system in the marked Markovian arrival flow. The service times of customers are exponentially distributed with parameters depending on the type of customer. A part of the available servers is reserved exclusively for service of first type customers. Customers who do not receive service upon arrival, can make repeated attempts. The system operation is influenced by random factors, leading to a change of the system parameters, including the total number of servers and the number of reserved servers. The behavior of the system is described by the multi-dimensional Markov chain. The generator of this Markov chain is constructed and the ergodicity condition is derived. Formulas for computation of the main performance measures of the system based on the stationary distribution of the Markov chain are derived. Numerical examples are presented.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.655-656
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• 2015

In this paper, diagnosis for 85 high voltage induction motors which have operated for more than 20 years in 18 wide area water supply offices were applied and the results of diagnosis were analysed. Furthermore, main factors that would be affecting rotor defects were selected and correlations between dependent variables which was magnitude for sideband frequency on current during operation and independent variables such as starting characteristic, operating time, number of operation, load factor, maker, rotation speed, capacity were analysed. It was clear that factors including starting characteristic, number of operation, maker, rotation speed caused break by correlation analysis. From this, regression equation was deduced through regression analysis. Based on suggested regression equation, it is applied usefully that we can estimate the condition of rotor without onsite diagnosis and plan the schedule of diagnosis.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.2
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• pp.164-168
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• 2010

The transformer is expected to be an essential component of a superconducting fault current limiter (SFCL) for both the increase of its voltage ratings and the simultaneous quench due to different critical current between high-$T_C$ superconducting (HTSC) elements comprising the SFCL. However, in order to perform the effective current limiting operation of the SFCL, the design for the SFCL considering the hysteresis characteristics of the iron core is required. In this paper, the influence of the hysteresis characteristics of the iron core comprising the transformer type SFCL on its current limiting characteristics was investigated. Through the comparative analysis on the hysteresis curves due to the ratio of the turn number between the 1st and the 2nd windings of the transformer, the proper design condition for the ratio of the turn number to achieve the effective current limiting operation of the transformer type SFCL could be obtained.

• Journal of Korean society of Dental Hygiene
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• v.20 no.5
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• pp.707-716
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• 2020

Objectives: This study aims to provide basic data for high-quality dental services. In addition, we will promote the operation of preventive dentistry that implements preventive measures. It was conducted to study the change of patient's treatment behavior and treatment cost due to the discontinuation of preventive dentistry in university dental hospitals. Methods: This study collected data using the integrated medical information system of the C University Dental Hospital. From September 1, 2017 to August 31, 2019, data were analyzed using frequency, percentage, mean, standard deviation, chi-square test using SPSS version 24.0 statistical program, and T-test. Results: There was a significant difference in the number of preventive dental treatment cases from 58.3% of preventive dental operation periods to 41.7% of preventive dental operation periods. As a result of comparing the medical expenses, the total medical expenses during the preventive dental operation period decreased from 521,308,872 won to 379,724,995 won during the discontinuation period, 141,583,877 won. The number of medical treatments by treatment behavior decreased 3,835 (28.4%) from a total of 13,520 preventive dental operation periods to 9,685. Conclusions: This study is meaningful as the first study to confirm the change in the treatment behavior and the change in the cost of treatment due to the discontinuation of the operation of preventive dentistry at university dental hospitals. In conclusion, it is thought that there is a possibility of the lack of accessibility and the limitation of professional preventive care due to the discontinuation of preventive dentistry.

• 전자공학회논문지 IE
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• v.44 no.3
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• pp.12-22
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• 2007

In this paper, we designed of the high speed digital neuron processor in order to digital neural networks. we designed of the MAC(Multiplier and Accumulator) operation unit used residue number system without carry propagation for the high speed operation. and we implemented sigmoid active function which make it difficult to design neuron processor. The Designed circuits are descripted by VHDL and synthesized by Compass tools. we designed of MAC operation unit and sigmoid processing unit are proved that it could run time 19.6 nsec on the simulation and decreased to hardware size about 50%, each order. Designed digital neuron processor can be implementation in parallel distributed processing system with desired real time processing, In this paper.