• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권10호
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• pp.2587-2600
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• 2012

It has been demonstrated that choosing an appropriate relay node can improve the transmission rate for the system. However, such system improvement brought by the relay selection may be degraded with the presence of the malicious relay nodes, which are selected but refuse to cooperate for transmissions deliberately. In this paper, we formulate the relay selection issue as a restless bandit problem with the objective to maximize the average rate, while considering the credibility of each relay node, which may be different at each time instant. Then the optimization problem is solved by using the priority-index heuristic method effectively. Furthermore, a low complexity algorithm is offered in order to facilitate the practical implementations. Simulation results are conducted to demonstrate the effectiveness of the proposed trust-based relay selection scheme.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1496-1499
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• 1997

Recently the major requirements have emerged in industrial substation system field. One is the simple arrangement of main power supply equipment and the other is the introduction of highly computer-controlled system for operation, maintenance and protection. This paper deals with the systems including motor-type relay systems, supervisory and control systems, digital type relay protectiion systems.

• 전기학회논문지
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• 제56권4호
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• pp.677-682
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• 2007

In the distribution system, Change of system happens frequently. However, most of the relays are operated manually by a person or not changed when system changed. So, when fault happened, a case that relaydoes not act rapidly happens. Also, in current power system, digital relays are used because of digitization of relay. Digital relay has very many advantages than existing analog relay. One of these advantages is that communication is available and easily can make characteristic curve. If specific values are sent to a relay by communication, A relay can make suitable characteristic curve according to the value. In this paper, by using voltages and currents measured by relay, state of CB(Circuit Breaker) and these relays, SCADA(Supervisory Control And Data Acquisition) system that control and correct characteristic curve of overcurrent relay at system change by using HMI(Human Machine Interface) is proposed.

• 한국정보통신학회논문지
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• 제20권11호
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• pp.2100-2106
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• 2016

자동화시스템은 PLC를 사용하여 생산제품의 제조 공정상태를 감시하고 센서에서 전달되는 센서정보를 처리한다. 본 연구에서는 자동화시스템에 사용되고 있는 제어용 계전기의 상태를 감시하는 원격감시시스템을 제안한다. 제안한 시스템은 제어 릴레이모듈, 원칩프로세서 모듈, 컴퓨터 모니터링시스템과 제어용 계전기의 내역을 입력하고 관리하는 데이터베이스시스템으로 구성한다. 컴퓨터 모니터링시스템은 제어용 계전기의 작동상태와 수명을 모터링할 수 있도록 구성하였고, 데이터베이스는 제어용 계전기의 투입 일자를 입력하고 수정이 가능하게 구성하였으며, 제어용 계전기의 작동상태의 정보를 자동으로 프린트할 수 있도록 구성하였다. 원격감시시스템에서 제어용 계전기의 고장상태를 실시간으로 파악하고, 고장부품을 신속하게 교체하여 정상가동에 소요되는 시간을 최소화할 수 있도록 하였다.

• 한국컴퓨터정보학회논문지
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• 제26권1호
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• pp.103-110
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• 2021

본 논문에서는 5G 무선 네트워크 D2D 시스템에서 수행될 수 있는 두 가지 액세스 제어 메커니즘들을 비교해 보고 효과적인 액세스 제어 기법을 제안한다. 현재 5G D2D 시스템에서는 액세스 제어 기법이 표준 규격에 제정 되어 있지 않고 있으나, 두 가지 액세스 제어 기법들이 가능하다. 하나의 방식으로는 UE-to-Network Relay 기반의 액세스 제어 기법이고, 다른 하나의 방식으로는 Remote UE 기반의 액세스 제어 기법이다. 전자의 경우는 UE-to-Network Relay가 액세스 제어 검사를 수행하는 것이며, 후자의 경우는 Remote UE가 액세스 제어 검사를 직접 수행하는 방식이다. 실험 평가 결과, 본 논문에서는 5G 무선 네트워크 D2D 시스템에서 효율적인 액세스 제어 방안으로써 Remote UE 기반의 액세스 제어 기법을 최종 제안한다. Remote UE 기반의 액세스 제어 기법은 UE-to-Network Relay 기반의 액세스 제어 기법이 비하여, 신호 오버헤드를 최소화하고, 서로 액세스 제어 기능들이 다른 경우 보다 효율적인 액세스 제어 검사를 수행할 수 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 하계학술대회 논문집 D
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• pp.997-999
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• 1997

This Paper presents a relay modeling technique to deal with the relay transient characteristics. Existing relay models are based on steady-state concepts. The ninth-order state space mathematical model of the Mho distance relay has been constructed. Computer modeling of a typical distance relay is done within the Transient Analysis of Control System(TACS) subsection of the ElectroMagnetic Transient Program(EMTP).

• KIEE International Transactions on Power Engineering
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• 제5A권2호
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• pp.144-151
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• 2005

This paper presents a framework for determining control strategies against unwanted tripping actions during relay operation that plays a very important role in cascading events leading to voltage collapse. The framework includes an algorithm for quick identification of possible zone 3 relay operation during voltage instability. Furthermore, it comes up with the control strategy of load shedding at the selected location with active power and relay margin criteria. In addition, Quasi Steady-State (QSS) simulation is employed to obtain time-related information that is valuable in the determination of control strategy. As a case study, an example applying the framework is shown with the modified New England 39-bus system.

• 한국산업융합학회 논문집
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• 제4권3호
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• pp.263-266
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• 2001

In this paper, intelligent methods using digital protection relay in power SCADA system is developed in order to protect power systems by means of timely fault detection during operation and control at starting for induction motor which have various load environments and capacities in power systems. The digital protective relay was designed with DSP CPU(TMS320C31) to protect and measure more quickly and precisely. The test result on the basis of KEMC 1120 and IEC60255, show that the operation time error of the digital motor protection relay is improved within ${\pm}5%$. Also, we can control motors at starting according to starting types with simple method as programmable sequence editor. So we can improve the demerits of high cost and much manhour for rework.

• International Journal of Control, Automation, and Systems
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• 제5권3호
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• pp.234-242
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• 2007

A Concurrent Relay-PID controller (CRPID) for motor position servo systems is proposed in this paper. The proposed controller is composed of a deadband-relay subcontroller and a parallel PID subcontroller. The deadband-relay subcontroller is capable of improving the transient system performance while the PID subcontroller is responsible for near steady state system regulation. Systematic design methods for various controller components are developed. Design procedures are illustrated by an example. The proposed hybrid scheme is applied to a DC motor position servo system. Both numerical and experimental results demonstrate that the proposed controller performs satisfactorily and is superior to PID control alone.

• ETRI Journal
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• 제36권2호
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• pp.280-285
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• 2014

In this paper, the optimal power control problem in a cooperative relay network is investigated and a new power control scheme is proposed based on a non-cooperative differential game. Optimal power allocated to each node for a relay is formulated using the Nash equilibrium in this paper, considering both the throughput and energy efficiency together. It is proved that the non-cooperative differential game algorithm is applicable and the optimal power level can be achieved.