• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권3호
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• pp.861-876
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• 2022

Cryptoassets such as Bitcoin and Ethereum are widely traded around the world. Cryptocurrencies are also transferred between investors. Cryptocurrency has become a new and attractive means of remittance. Thus, blockchain-based smart contracts also attract attention when central banks design digital currencies. However, it has been discovered that a significant amount of cryptoassets on blockchain are lost or stranded for a variety of reasons, including the loss of the private key or the owner's death. To address this issue, we propose a method for recoverable transactions that would replace the traditional transaction by allowing cryptoassets to be sent to a backup account address after a deadline has passed. We provide the computational workload required for our method by analyzing the prototype. The method proposed in this paper can be considered as a good model for digital currency design, including central bank digital currency (CBDC).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.188-194
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• 2011

The purpose of this paper is to explain the implementation method in order to enhance stability and reliability of embedded system. In this research, Texas Instrument (TI)'s TMS570 MCU(Micro Controller Unit) is used to satisfy the standard of stability that is IEC 61508. IEC 61508 suggest SIL(Safety Integrity Level) from 1 to 4 and TMS570 is satisfied SIL3. Also, TMS570 can provide several stability functions can be used in realtime system. To use such functions, this paper suggest the solution about the defect that can be used in realtime system. In basic way TMR(Triple Modular Redundancy) suggested in addition to explain about the way to improve safety and reliability. Also this paper will suggest the method that reinforce the stability of calculation by using multiplex voter and memory.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 B
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• pp.731-733
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• 1999

Distributed Control System has been used for large scale and critical system control such as aerospace industries, chemical and power plant and so on. It is very impotant factors for design of the control system to be reliable and fault-tolerant. These control systems have backup or redundant processing modules for minimizing the time of failure and improving reliability. But such methods have changeover duration from faulty module to healthy one. During that interval, feedback control loop raises bumper and performance of the system become worse. TMR(Triple Modular Redundancy) control system is one of the best reliable ones that can overcome such a mortal drawback. This paper analyzes the components of TMR system functionally and proposes practical and cost effective configuration method for turbine control of thermal power plant.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.121.4-121
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• 2001

We propose an off-line methodology for detecting a faulty backup roll that generates eccentricity components, under the condition that the feeding velocity, equivalently the angular velocity of roll, is not constant. From a newly devised speed angle conversion algorithm, we transform all process data into those of a virtual process under a constant feeding speed. This indirectly way, we can apply a spectral analysis to the original process. In addition, we develop an online detection method of roll eccentricity based on newly designed PLG sensor. This PLG sensor is robust because of applying magnetic proximity sensnors and non-contact measurement method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 A
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• pp.187-189
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• 2003

This paper presents new service restoration algorithm to deal with multiple faults such as main transformer fault, whole substation fault and simultaneous faults. The most important consideration of restoration planning for multiple outage areas is efficient use of redundant backup feeders. The proposed algorithm tries to restore all outage loads using outage area ordering method and tie switch exchange method that are newly proposed in this paper.

• 전기학회논문지
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• 제61권8호
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• pp.1107-1114
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• 2012

In this paper, we propose protective coordination and automatic setting method using agents for distribution system with loop. The proposed protection scheme adopts an agent technology assuming communication among protection agents and auto-switch agents. Having exchanged fault-related information with each other, protection agents and auto-switch agents perform the primary and backup protection and fault section isolation, respectively. this proposed scheme using agents for distribution system with loop is implemented by matlab. Because of the various configuration of distribution system, It's difficult to find cooperative agents for each agent. This paper develops a program to automatically set the cooperative route for the agents.

• 전기학회논문지
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• 제67권9호
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• pp.1141-1145
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• 2018

Generally, in nuclear plants, distance relay (21R) has adapting to protect and to operate main protective of transmission lines and backup protective of main generator. Operation of 21R was required and based on exactly accurate calculation and criteria. But presently method of 21R setting has applied according to protection devices operation guide of KPX, excepting IEEE and ISA standards, which have a difference review directions, consider parameters and devices, also consideration factors were affected to relay operations by uncertain guides. therefore this paper proposed new protection relay setting method and unvague criteria from IEEE 741 and ANSI/ISA 67.04.01, and reviewed a different results through numerical calculation results for methods and criteria including previous and established 21r setting by IEEE, ANSI/ISA Technical standards.

• 한국콘텐츠학회논문지
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• 제10권9호
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• pp.68-78
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• 2010

확장성 문제와 도메인간 상호 동작성 문제 등으로 인해 인터넷에서 IP 멀티캐스트 기능의 지원이 지연되고 있음에 따라 IPTV와 같은 실시간 멀티미디어의 멀티캐스트 응용을 P2P(Peer-to-Peer) 방식으로 지원하는 P2P 스트리밍 기술에 대한 관심이 고조되고 있다. 본 논문은 참여자간 상호 작용이 보다 활발한 개인 IPTV와 비디오 컨퍼런스 등과 같이 QoS(Quality of Service)에 민감한 멀티미디어 멀티캐스트 응용을 위한 P2P 스트리밍 기법을 제시한다. 본 논문에서 제시한 P2P 스트리밍 기법은 응용이 자신의 신뢰성 요구에 부합되도록 백업 피어(Backup Peer)가 배치된 P2P 스트리밍 트리를 구축함으로써 피어 이탈에 따른 재연결 지연(Reconnection Delay)을 축소하여 그에 따른 스트리밍 데이터의 손실을 최소화한다. 그리고 피어의 대역폭 정보와 종단간 지연시간 정보를 분산 방식으로 유지함으로써 참여 피어가 연결될 목표 피어를 신속하게 결정할 수 있게 하여 피어의 참여 지연시간인 스타트업 지연시간(Startup Delay) 획기적으로 줄인다. 또한 본 논문에서 제시한 P2P 스트리밍 기법은 대역폭과 종단간 지연 시간에 따른 피어 수락 제어(Peer Admission Control) 기능을 제공함으로써 멀티캐스트 응용의 종단간 지연 시간 요구사항에 부합되는 스트리밍 서비스를 제공한다.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.452-464
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• 2015

This paper proposes a DC microgrid operational strategy and control method for improved service reliability. The objective is to supply power to as many non-critical loads as possible, while providing an uninterrupted power supply to critical loads. The DC bus signaling method, in which DC voltage is an information carrier, is employed to implement the operational strategy in a decentralized manner. During grid-connected operation, a grid-tied converter balances the power of the microgrid by controlling the DC voltage. All loads are connected to the microgrid, and operate normally. During islanded operation, distributed generators (DGs), a backup generator, or an energy storage system balances the power. However, some non-critical loads may be disconnected from the microgrid to ensure the uninterrupted power supply to critical loads. For enhanced service reliability, disconnected loads can be automatically reconnected if certain conditions are satisfied. Control rules are proposed for all devices, and detailed microgrid operational modes and transition conditions are then discussed. Additionally, methods to determine control parameter settings are proposed. PSCAD/EMTDC simulation results demonstrate the performance and effectiveness of the proposed operational strategy and control method.

• International Journal of Industrial Entomology and Biomaterials
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• 제15권1호
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• pp.1-7
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• 2007

At present, multivoltine silkworm races reared five times per year involving huge manpower and rearing expenditure. Egg diapausing behavior is facultative in multivoltine and egg diapause was induced in selected multivoltine races by regulating temperature at $18^{\circ}C$, relative humidity 80% and photoperiod (6L:18D) in the late stage silkworm rearing. The maximum percentage of egg diapause induction was recorded in Rong Diazo, Diazo and MW13 showed 94%, 93% and 92% respectively, whereas the races A14DY and OS-616 showed minimum diapause induction 15% and 18% respectively. The diapause induced multivoltine eggs were preserved up to six months by cold preservation schedule normally adopted for bivoltine. After three and six months egg preservation, the diapause induced layings were released and observed for hatching percentage, all races showed above 82 % of hatching except the race AP12, which showed only 78 % of hatching. This methods reduce the crop cycle, gives strong safety backup and preventing the genetic erosion. This study helps formulating a new conservation method for multivoltine silkworm germplasm.