• Journal of Advanced Marine Engineering and Technology
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• v.36 no.7
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• pp.935-941
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• 2012

This paper describes a study of conventional electrical rig and simulated application of Flywheel Energy Storage system on the power system of the offshore plants with dynamic positioning system with the following aims: improve fuel consumption on engines, prevent blackout and mitigate voltage sags due to pulsed load and fault. Fuel consumption has been analyzed for the generators of the typical drilling rigs compared with the power plant with Flywheel Storage Unit which has an important aid in avoiding power interruption during DP (Dynamic Positioning) operation. The FES (Fly wheel Energy storage System) releases energy very quickly and efficiently to ensure continuity of the power supply to essential consumers such as auxiliary machinery and thrusters upon main power failure. It will run until the standby diesel generator can start and supply the electric power to the facilities to keep the vessel in correct position under DP operation. The proposed backup method to utilize the quick and large energy storage Flywheel system can be optimized in any power system design on offshore plant.

• Journal of the Korean Solar Energy Society
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• v.30 no.3
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• pp.25-32
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• 2010

A real-time monitoring system was developed for transfer, receive, backup and analysis of wind power data at three wind farm(Hang won, Hankyung and Sung san) in Jeju. For this monitoring system a communication system analysis, a collection of data and transmission module development, data base construction and data analysis and management module was developed, respectively. These modules deal with mechanical, electrical and environmental problem. Especially, time series graphic is supported by the data analysis and management module automatically. The time series graphic make easier to raw data analysis. Also, the real-time monitoring system is connected with wind power forecasting system through internet web for data transfer to wind power forecasting system's data base.

• Journal of Digital Contents Society
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• v.19 no.3
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• pp.497-503
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• 2018

RHEL 7, the leader in the enterprise Linux market, has dramatically increased the maximum support specification, such as file system size, file size, etc., by changing the default file system from EXT to XFS. It's not just an increase in support specifications, it's working on daemons, and it's showing excellent performance on high-performance disks such as high-capacity disks and solid state drives. Changes in the file system mean changes in direct operating techniques, such as changing related commands, changing backup tools, and changing disk quota settings. The changes to the XFS file system are making a lot of changes to the operation of the Linux system, but we believe that the position of the Linux operating system in the server field will become stronger.

• Journal of Positioning, Navigation, and Timing
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• v.9 no.2
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• pp.99-115
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• 2020

Since GNSS is easily affected by jamming and/or spoofing, alternative navigation systems can be operated as backup system to prepare for outage of GNSS. Alternative navigation systems are being researched over the world, and a multi-radio integrated navigation system using alternative navigation systems such as KNSS, eLoran, Loran-C, DME, VOR has been researched in Korea. Least Square or Kalman filter can be used to estimate navigation parameters in the navigation system. A large number of measurements of the Kalman filter may lead to heavy computational load. The decentralized Kalman filter and the federated Kalman filter were proposed to handle this problem. In this paper, the decentralized Kalman filter and the federated Kalman filter are designed for the multi-radio integrated navigation system and the performance evaluation result are presented. The decentralized Kalman filter and the federated Kalman filter consists of local filters and a master filter. The navigation parameter is estimated by local filters and master filter compensates navigation parameter from the local filters. Characteristics of three Kalman filters for a linear system and nonlinear system are investigated, and the performance evaluation results of the three Kalman filters for multi-radio integrated navigation system are compared.

• Journal of KSNVE
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• v.4 no.1
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• pp.43-50
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• 1994

Chatter vibration of a rolling machine in steel plants has a significant effect on thickness quality of the products. The cause and mechanism of the mill chattering is addressed through measurement of vibration and dynamic torque. An FFT system and an FM telemetry system are employed to collect data at several locations of possible damages. The results reveal the followings as sources of the mill vibration. The first is defects in roller bearings of a work roll chock. The second is instability of an oil film bearing in a backup roll chock, which has been investigated with a theoretical model describing the phenomenon. Dynamic torque is not the direct cause of mill vibration but rather influenced by the vibration. Appropriate treatment methods are suggested to address each of the above sources.

• Proceedings of the Korean Society of Computer Information Conference
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• 2013.07a
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• pp.115-117
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• 2013

최근 금융권에서 전산망에 있는 자료가 대규모로 손상되어 수일에 걸쳐 전체 또는 일부 서비스 이용이 마비된 금융 대란 사건이 발생했다. 대학의 학사행정 정보시스템은 금융권의 전산망 보다 안정성이 더욱 취약한 것이 사실이다. 본 논문은 재난 복구에 대한 이론적 고찰을 통해 재난 복구의 유형화의 주요 내용을 살펴보고 대학의 학사행정 정보시스템이 장애가 발생했을 때 MS 윈도우 기반 PC에서 업무가 수행될 수 있도록 가용성을 확보할 수 있는 백업시스템을 설계하였다.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.235-239
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• 2002

Combined generation system of photovoltaic and wind power is required backup system that such as a storage battery to supply energy, when not enough photovoltaic and wind power source for power supply equally and continually, because the energy source is changeable and stable through change of weather as irradiation, temperature, wind speed, wind speed, wind direction, seasons, etc..

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.2
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• pp.58-64
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• 2009

The existing note on mobile can store only text data and cannot share the data, which means that the notes stored on mobile are just seasonal or temporary memo. Therefore, this research designs an improved note on mobile and gives a chance for sharing by importing a concept of Mindmap and backup server through the internet. The mobile application is developed based on Android Platform and the server applications are developed based on Linux. These can communicate each other throughout the internet to upload and download some mindmap data.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.557-560
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• 2008

본 논문에서는 유비쿼터스 지능형교통시스템(u-ITS: Ubiquitous Intelligent Transportation System)에서 발생하는 다량의 데이터를 실시간 저장하기 위해 메인 메모리 데이터베이스(MMDB: Main Memory Database)와 디스크 상주 데이터베이스(DRDB: Disk Resident Database)를 사용하는 시스템 구조와 RM(Rate Monotonic)를 기반으로 데이터의 발생 주기에 따라 MMDB와 DRDB에 실시간 저장하는 알고리즘을 제안한다.

• Journal of Korean Society for Atmospheric Environment
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• v.27 no.1
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• pp.63-72
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• 2011

This study describes the impact of positive sampling artifact caused by a filter-based sampling in the determination of ambient organic carbon (OC). Three different sampling media combinations were employed for this investigation: (1) Quartz filter-alone (Q-alone), (2) quartz filter behind quartz-fiber filter (QBQ), and (3) quartz filter and quartz filter behind Teflon filter (Q-QBT). The measurement of ambient OC was carried out at a semi-urban site near oceanside at the end of November of 2008. It was found that Q-alone sampling configuration resulted in a higher OC than QBQ and Q-QBT by 14% and 28%, respectively due to no correction for positive artifact caused by adsorption of gas-phase OC onto the filter. A lower quantity of OC was collected from the backup quartz filter on QBQ than that from Q-QBT. A possible explanation is that the front quartz filter of QBQ was not fully saturated with gas-phase OC during the sampling period, allowing smaller amount of gas-phase OC to reach the backup quartz filter. The contribution of positive artifact to $PM_{2.5}$ mass was approximately 2.15 ${\mu}g/m^3$ which is equivalent to 6% in terms of Q-QBT sampling configuration. The positive artifact was found to be more dominated during summer than during winter, showing temperature dependence. It was concluded that Q-QBT sampling configuration offers less impact of positive artifact on ambient OC sampling than QBQ in quantification of OC.