• KIEE International Transactions on Power Engineering
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• v.4A no.1
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• pp.42-47
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• 2004

This paper presents the various application programs for the Distribution Automation System (DAS) of the Korea Electric Power Corporation (KEPCO)'s distribution system. These programs are developed to allow for optimal operation in the areas of feeder automation, relay coordination, loss minimization and so on. They are single line diagram auto creation programs for the feeder, service restoration program, protection coordination program, data error detection program, and optimal network reconfiguration program. The details of these programs are presented for validity and effectiveness.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.3
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• pp.107-116
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• 2007

The introduction of new renewable energy is going on increase with the second plan of the Korean Government "Technology Development, Utilization and Popularization of New Renewable Energy". In general, it is connected to the power system due to the nature of it's source characteristics but it's interconnection operation impacts on the power system planning and operation. The operation schemes of the existing power distribution system are based on the unidirectional power flow, but unidirectional power flow changes to bidirectional power flow due to the interconnection operation of new renewable energy. It degrade the existing protection coordination system and power quality of the power distribution system. Thus, the technical evaluation process of the interconnection of new renewable energy are necessary. In this paper, the characteristics of the existing automatic recloser and sectionalizer are reviewed and interconnection capacity evaluation method of the DR(distributed resources) in the existing automatic recloser-sectionalizer protective coordination system are proposed.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.1
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• pp.1-7
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• 2015

In this paper, we have described target positioning of automatic survey system. Target positioning error analysis shows target positioning errors are mainly dependent on the vertical angle of the triangle configured by target and two measurement points. Suggested target positioning error formula are confirmed by simulation using the Gaussian distribution.

• Journal of the Korea Safety Management & Science
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• v.16 no.2
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• pp.139-146
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• 2014

In Korea's distribution and production field establishment of logistics information system and automation of logistics were greatly developed. But there is no characteristic and professionalism about hospital logistics, and distribution center is located in outside warehouse, logistics system is very important. Since hospital has human power to receive product, system is not as much required, but outside warehouse requires system for arrival from medicine and medical supplies wholesale dealer and vender, warehousing, storage, and automation facilities, and system for various works such as peaking instruction, classification, packing, cargo-working, delivery, order of medicine from hospital and non-medicine in hospital is essential. Therefore, This study is about development of automatic identification of slide which cannot be overlooked in efficiency of hospital logistics, establishment of database, and information interlocking between automatic storage system and outside warehouse.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.870-873
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• 1991

In this paper, We present demodulation and synchronization method of phase shift keying signal using Double Frequency Vector Technique for Reference Vector. 2nd Harmonic Vector for Reference Vector is utilized in discriminating between noise and carrier signal, and in producting correlation value for data bit logical level. And we applied this demodulator to Automatic Meter Reading System being communicated with electric distribution power lines.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.1
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• pp.28-37
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• 2001

This paper presents an efficient algorithm for the loss minimization of distribution system by automatic sectionalizing switch operation in large scale distribution systems. Simulated annealing is particularly well suited for large combinational optimization problem, but the use of this algorithm is also responsible for an excessive computation time requirement. Tabu search attempts to determine a better solution in the manner of a greatest-descent algorithm, but it can not give any guarantee for the convergence property. The hybrid algorithm of two methods with two tabu lists and the proposed perturbation mechanism is applied to improve the computation time and convergence property Numerical examples demonstrate the validity and effectiveness of the proposed methodology using a KEPCO's distribution system.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.58
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• pp.59-69
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• 2000

Development of digital information and internet technology causes the changes of technology environments and companies, and the variety of customer needs has been dynamically changed in terms of integrating information system with customer satisfaction. Moreover a new logistics concept is needed through the sharing information between suppliers and consumers, which maximizes the level of customers service and its flexibility by changing functional-oriented to process-oriented. In other words, Supply Chain Management (SCM) is now considered as a key aspect of business, which controls the flows of information, funds, and goods in the supply chain. Rationalization of transport-delivery system will be one of the most important issues on logistics management to the domestic companies. The companies need the effective delivery system. Especially in the case of delivery system from distribution centers to customers or vendors, it might take a long time to control the delivery system manually because it would be hard to apply the automatic vehicle routing algorithm effectively considering all the practical constraints. Thus this study develops a heuristic algorithm of automatic vehicle delivery support system in terms of grouping by short ranges of vehicle movement utilizing postal coordinates, which satisfies a variety of realistic constraints and reduces controlling time of manual operations. In addition, the performance of the algorithm developed in this study is evaluated through the case study.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.5
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• pp.67-73
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• 1996

The necessity for more accurate automatic flatness control(AFC) system has increased of customers' requirement for cold rolled steel sheet. Therefore, many cold rolling mills replaced its AFC system with a measuring roll of the contact type form the non-contact type. In this paper. The performance of AFC system of contact type has been investigated under industrial conditions. It has two kinds of actuator: roll bender, spot cooling system. The test results are as follows: The more strip thickness is thick, the smaller the I value, and the more it is thin, the bigger the I value. And a complex distribution of strip tension was controlled, for example, not only a pocket wave but also a simple center wave and edge wave. Because the tension deviation is larger at acceler- ation speed and decelerationspeed than steady speed, AFC system of contact type is better to adopt over 50m/mim. AFC system reduces rapidly large flatness deviation. The maximum I value of strip has been decreased to 13 I, and sticker, defects caused by poor flatness, have been decreased about 60%.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.10
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• pp.36-45
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• 1996

The precise estimation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission is necessary in order to enable accurate material and geometric properties to reliability distrobution and the number of load cycles at failure. These are critical for the proba- bilistic design of complex planetary gear system as Ravigneaux type particularly during various gear ratios. The Ravigneaux planetary gear train has five gears, such as a forward and a reverse sun gear, a short and a long pinion, and an annulus gear. In this paper, the Ravigneaux gear system is analyzed to figure out the reliablity distribution. i.e. the probability of survival in the system without its overhaul. First, the reliablity method based on the Weibull distribution is used in conjuction with the Palmgren's model to predict both the individual reliabilities of its components and the nimber of load cycles when the system failed. Then using the presented method, the life of the Ravigneaux gear system can be determined. Alwo the different design parameters such as tooth face width, material property, and Weibull exponent are applied and reached to optimal ones. Thus, the precise evaluation of the reliability and life of the Ravigneaux planetary gear train used in an automatic transmission can be effectively carried out.

• Journal of Integrative Natural Science
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• v.16 no.4
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• pp.139-145
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• 2023

Due to changes in the distribution system and increased demand for renewable energy, interest in technology to increase the limit capacity of distributed energy grid connection using grid flexible resources is also increasing. Recently, the distribution system system is changing due to the increase in distributed power from renewable energy, and as a result, problems with the limited capacity of the distribution system, such as waiting for renewable energy to connect and increased overload, are occurring. According to the power generation facility status report provided by the Korea Power Exchange, of the total power generation capacity of 134,020 MW as of 2021, power generation capacity through new and renewable energy facilities is 24,855 MW, accounting for approximately 19%, and among them, power generation through solar power accounts for a total portion of the total. It was analyzed that the proportion of solar power generation facilities was high, accounting for 75%. In the future, the proportion of new and renewable energy power generation facilities is expected to increase, and accordingly, an efficient operation plan for the distribution system is needed. Advanced country-type NWAs that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power in order to improve distribution network use efficiency without expanding distribution facilities due to the expansion of renewable energy. An integrated operating system is needed. In this study, in order to improve the efficiency of distribution network use without expanding distribution facilities due to the expansion of renewable energy, we developed a method that can integrate the operation and management of load characteristics for each line of the distribution system, power distribution, regional characteristics, and economic feasibility of distributed power. We want to develop an integrated operation system for NWAs similar to that of advanced countries.