• Journal of Information Processing Systems
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• v.17 no.6
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• pp.1071-1082
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• 2021

Since the smart factory has been recently recognized as an industrial core requirement, various mechanisms to ensure efficient and stable operation have attracted much attention. This attention is based on the fact that in a smart factory environment where operating processes, such as facility control, data collection, and decision making are automated, the disruption of processes due to problems such as facility anomalies causes considerable losses. Although many studies have considered methods to prevent such losses, few have investigated how to effectively apply the solutions. This study proposes a Kubernetes based system applied in a smart factory providing effective operation and facility management. To develop the system, we employed a useful and popular open source project, and adopted deep learning based anomaly detection model for multi-sensor anomaly detection. This can be easily modified without interruption by changing the container image for inference. Through experiments, we have verified that the proposed method can provide system stability through nondisruptive maintenance, monitoring and non-disruptive updates for anomaly detection models.

• Journal of computational fluids engineering
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• v.10 no.2
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• pp.1-6
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• 2005

The HANARO, a multi-purpose research reactor of 30 MWth, open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. The HANARO is composed af inlet plenum, grid plate, core channel with flow tubes and chimney. The reactor core channel is located at about twelve meters (12 m) depth of the reactor pool and cooled by the upward flow that the coolant enters the lower inlet of the plenum, rises up through the grid plate and the core channel and comes out from the outlet of chimney. A fission moly guide tube is extended from the reactor core to the top of the reactor chimney for easily loading a fission moly target under the reactor normal operation. But active coolant through the core can be quickly raised up to the top of the chimney through the guide tube by jet flow. This paper describes an analytical analysis that is the study of the flow behavior through the guide tube under reactor normal operation and unloading the target. As results, it was conformed through the analysis results that the flow rate, reduced to about fourteen kilogram per second (14 kg/s) from the original flow rate of sixteen point three kilogram per second (16.3 kg/s) did not show the guide tube jet.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1835-1840
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• 2004

The HANARO, a multi-purpose research reactor of 30 MWth, open-tank-in-pool type, has been under normal operation since its initial criticality in February, 1995. The HANARO is composed of inlet plenum, grid plate, core channel with flow tubes and chimney. The reactor core channel is located at about twelve meters (12 m) depth of the reactor pool and cooled by the upward flow that the coolant enters the lower inlet of the plenum,. rises up through the grid plate and the core channel and comes out from the outlet of chimney. A guide tube is extended from the reactor core to the top of the reactor chimney for easily un/loading a target under the reactor normal operation. But active coolant through the core can be quickly raised up to the top of the chimney through the guide tube by a jet flow. This paper describes an analytical analysis that is the study of the flow behavior through the guide tube under reactor normal operation and unloading the target. As results, it was conformed through the analysis results that the guide jet is suppressed under the top of the chimney after modifying the orifice diameter of 37.5 mm to 31 mm.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.671-678
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• 2009

This paper presents target operation voltage guidelines of each voltage control area considering both voltage stability and economical efficiency in real power system. EMS(Energy Management System) data, Real-time simulator, shows not only voltage level but lots of information about real power system. Also this paper performs optimal power flow calculation of three objective functions to propose the best target operation voltage. objective function of interchange power flow maximum and active power loss minimization stand for economical efficiency index and reactive power reserve maximum objective unction represents stability index. Then through simulation result using optimazation technique, the most effective objective function is chosen. To sum up, this paper divides voltage control area into twelve considering electric distance characteristics and estimate or voltage level by the passage of time of EMS peak data. And through optimization technique target operation voltage of each voltage control area is estimated and compare heir result. Then it is proposed that the best scenario to keep up voltage stability and maximize economical efficiency in real power system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.7
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• pp.981-986
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• 2018

AC(alternating current) CB(circuit breaker) at the fault occurred in the existing AC distribution system is limiting the fault current through zero cross-point. However, DC(direct current) CB does not have zero cross-point. Therefore, arc occurred by on-off operation of DC CB is very huge. Nowadays, many research team are studying the way to decrease breaking time, which is one of the essential conditions in DC CB. We suggested novel arc-induction type DC CB in this paper. The proposed arc-induction type DC CB is composed of the mechanical Arc ring and DC CB. We confirmed the operation of arc-induction type DC CB through the HFSS(High Frequency Structure Simulator) 3D simulation program and performed the experiment for operation characteristics. Results showed that arcing time of the arc-induction type DC CB by using induction ring was faster than existing mechanical DC CB. On the transient system, we confirmed stable operation characteristics of the arc-induction type DC CB through the simulation and experimental results. We expect that the proposed arc-induction type DC CB technology is will go to stay ahead of the existing DC CB technology.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2127-2137
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• 2017

A virtual power plant (VPP) is a system that virtually integrates power resources based on the VPP participating customer (VPC) unit and operates as a power plant. When VPP operators manage resources to maximize their benefits, load reduction instructions may focus on more responsive VPCs, or those producing high profitability, by using VPC resources with high operation efficiency. VPCs may thus encounter imbalance problems during operation. This imbalance in operation time would bring more participation for some VPCs, causing potential degradation of their resources. Such an operation strategy would be not preferable for VPP operators in managing the relationship with VPCs. This issue impedes both continual VPC participation and economical and reliable VPP operation in the long term. An operation algorithm is therefore proposed that considers the operation time of VPC generators for mandatory reduction of power resource consumption. The algorithm is based on constraints of daily and annual operation times when VPP operators of local generators perform capacity-market power transactions. The algorithm maximizes the operator benefit through VPP operations. The algorithm implements a penalty parameter for imbalances in operation times spent by VPC generators in fulfilling their obligations. An evaluation was conducted on VPP operational effects by applying the algorithm to the Korean power market.

• East Asian mathematical journal
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• v.31 no.2
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• pp.211-244
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• 2015

The arithmetic operation have double-sided character. One is calculation as a process, the other is understanding in results as an outcome of the operation. We harbored suspicion on students' misunderstanding in an outcome of the operation, because the curriculum has focused on the calculation, as a process of arithmetic operation. This study starts with the presentation of this problem, we tried to find the recognition ability and character in the arithmetic operation. We researched the recognition ability for 7th grade 27 students who have enough experience in arithmetic operation when studying in elementary school. And we had an interview with 3students individually, that has an error in understanding in results of arithmetic operation but has no error in calculation. We focused on 3students' detailed appearance of the ability to understand in results of arithmetic operation and analysed the changing appearance after recommending unit record using operation expression. As a result, we could find the abily to underatanding in results of arithmetic operation and applicability to recommend unit record using operation expression. Through these results, we suggested educational implications in understanding in results of arithmetic operation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.11
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• pp.61-68
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• 2009

A Microgrid is a private small-scale power system composed of distributed energy resources (DERs), storage devices and loads. And it is expected that the Microgrid will come into wide use in the near future. For this, the establishment of the Microgrid operation methodology is a very important problem. Especially, the Microgrid is greatly different from existing private small-scale power systems because of the multiple participants. Therefore, the Microgrid operation considered various requirements according to multiple participants is more complicated than the operation of existing private small-scale power systems. In this paper, Microgrid operation methodology based on a market environment is suggested. Through case studies, the effectiveness of the suggested methodology is verified.

• Proceedings of the KIEE Conference
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• 2002.11b
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• pp.29-31
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• 2002

Purpose of the 765kV trial operation conducted for the first time in our country are performance verification of domestic developed equipment(765kV M.Tr, GIS,etc) and extraction of problem in advance to commercial operation and cultivation of operation ability. The trial operation of 765kV substation was finished successfully under the positive supports of institutes. manufactures. and constructers. It is expected that extraction of problems in advance and accumulation of operation techniques through the trial operation of 765kV substation will be contributed largly to the realization of the without a hitch operation of 765kV system.

• Journal of Positioning, Navigation, and Timing
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• v.12 no.4
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• pp.431-436
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• 2023

In order to provide continuous Korea Augmentation Satellite System (KASS) services, the operation organization should continuously and systematically perform operations, maintenance, and technical activities. All subsystems of KASS, all Line Replacement Units (LRUs), and Software Replacement Units (SWRUs) should be operated and maintained continuously. In order to effectively manage these activities, it is necessary to develop an Operation Management Tool (OMT). For this purpose, operation management, operation organization, and operation activities were defined. The defined requirements were divided into general, function, interface, and database for OMT development, and functions and decision-making procedures consisting of site/asset/trouble/work order/schedule management were designed. The OMT developed by reflecting the site and asset information as well as the design content met predefined requirements. The OMT will be actively used in actual KASS operation and will evolve by continuously reflecting the additional requirements of operators. Through this tool, KASS will support continuous service provision.