• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.211-212
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• 1998

In this experiment, we developed a mind switching device which uses $\alpha$-wave with its amplitude varying between the eye-open and closed states. If the subject closes eyes, the switch toggles with a small delay. The circuit consists of an amplifier, a filter and a switch. An instrument amplifier is used fur high CMRR and for high input impedance. An 8th order Butterworth filter was able to reduce noise satisfactorily. The signal is then converted to a DC level, and finally a Schmitt trigger was used to generate a switching pulse.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.95-97
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• 1995

A superconducting current generator, or a superconducting rectifier(SCR) is used as a current source to energize a superconducting magnets in SMES, MRI. We selected a full-wave SCR among various SCR models and analyzed its operational characteristics by computer simulation. In process of pumping the current, the improvement of performance is dependent on how much bigger the open resistance of the switch is in comparison to load coil impedance when one of two switches become active. Faster transfer can he seen in resistive commutation mode by shortening the time elapsed for the resistance to arrive at certain level from zero state. Although recovery time for the switch has no direct effect on current pumping, optimal switch design is needed to increasing operational frequency.

• 전자공학회논문지S
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• 제36S권10호
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• pp.40-50
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• 1999

서비스의 다양화, 고기능화, 고객의 요구에 부응하는 통신 네트워크에 대한 새로운 요구가 일어나고 있다. 따라서 ATM 전달망의 특징을 이용한 개방형 네트워크 구조에 대한 연구가 활발히 이루어지고 있다. 본 논문에서는 ATM 네트워크의 전달망을 스위치 네트워크로 이용하는 VSN(Virtual Switch Network) 개념을 IMT-2000 스위칭 시스템에 적용하고, 호 처리과정을 이용하여 VSN의 특성을 평가한다. 이 결과를 기본으로 VSN 기반 제어계 집약형 ATM-MSC 노드 구조를 제시하고, 호 처리 절차를 이용하여 VSN의 특성을 평가한다. 그 결과, 3.5msec 정도의 호 처리 지연을 허용하면, CCCP(Call and Connection Control Processor)를 중심으로 반경 100km내에서 VSN을 이용한 ATM-MSC 시스템 구성이 가능함을 나타낸다. 그리고 VSN 개념을 적용한 ATM-MSC 시스템 구성의 가능성과 VSN의 타당성을 분명히 한다.

• 조명전기설비학회논문지
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• 제26권3호
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• pp.61-68
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• 2012

This paper deals with a fault diagnosis algorithm for open faults in the switching devices of PWM inverter-fed IPMSM (Interior Permanent Magnet Synchronous Motor) drive. The proposed diagnostic algorithm is realized in the controller using the informations of three-phase currents or reference line-to-line voltages, without requiring additional equipments for fault detection. Under switch open fault conditions, the conventional dq model used to control an AC motor cannot directly be applied for the analysis of drive system, since three-phase balanced condition does not hold. To overcome this limitation, a fault model based on the line-to-line voltages is employed for the simulation studies. For comparative performance evaluation through the experiments, the entire control system is implemented using digital signal processor (DSP) TMS320F28335. Simulations and experimental results are presented to verify the validity of the proposed diagnosis algorithm.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.97-104
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• 2014

Automobile trunk latches enable trunks to be opened and closed by a latch mechanism, which can be selectively positioned between a locked condition and an open condition. To maintain structural and electronic performance of the trunk latch, the latch needs to endure impact load that occurs in its open and close motion, and a dynamic mechanism needs to be electronically controled by a contact switch connected with a small DC motor. A base plate, which is the most important component relating to the structural safety, commonly uses a high stiffness material SAPH440-P with high manufacturing cost. In this paper, through structural analysis and optimization, production cost is significantly reduced by replacing SAPH440-P used in some region of the base plate with engineering plastic PBT GF 20%. The optimized contact switch reduces difference between distributed pressures of its two legs, which leads to improve the electronic performance of the trunk latch.

• 디지털산업정보학회논문지
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• 제14권3호
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• pp.29-38
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• 2018

It is the approach of embedded system design that analyzes COS(Cut Out Switch) failure in the power distribution and an instantaneous breakdown of power distribution supply could cause the weakness of industrial competence and therefore we need to feed the stable power distribution with developing the technology of open-source embedded system. In this paper, we apply the LoRa technology which is the Internet of Things(IoT) protocol for low data rate, low power, low cost and long range sensor applications. We designed the hardware and software architecture setup and experimented the embedded system with network architecture and COS monitoring system including accelerometer for detecting the failure of distribution line and sensing the failure of its fuse holder by recognizing the variation and collision and afterwards sending the information to a gateway. With experimenting we designed the embedded platform for sensing the variation and collision according to the COS failure, monitoring its fuse holder status and transferring the information of states with LoRa technology.

• 한국산학기술학회논문지
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• 제8권5호
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• pp.1076-1081
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• 2007

본 논문은 시분할 송수신 시스템에 사용될 수 있는 새로운 구조의 스위칭회로를 제안한다. 기존의 시분할 송수신 시스템에 사용되는 스위칭 회로의 경우 안테나, 송신단 그리고 수신단을 서큘레이터로 각 단자를 분리하였다. 이러한 기존의 방법은 서큘레이터 사용으로 인하여 회로전체의 가격을 증가시키는 원인이 되며, 원치 않는 상호 변복조 성분이 만들어져 전체 시스템의 악화로 이어지게 된다. 본 논문에서 제안하는 회로는 비선형 소자인 서큘레이터를 사용하지 않고 기본적인 가지선로 결합기의 한 쪽 선로를 결합선로로 등가 모델링하여 응용한 회로이다. 이 회로는 등가 모델링 된 결합선로의 격리 포트를 개방/단락의 종단조건을 이용하여 신호의 흐름을 제어하는 새로운 구조의 스위칭회로이다. 본 논문에서는 제시한 설계법의 타당성을 검증하기 위하여 Wibro 서비스 주파수대역인 2.3GHz에서 제작 및 측정하였다.

• 전력전자학회논문지
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• 제18권3호
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• pp.217-224
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• 2013

This paper presents a diagnostic method for a sparse matrix converter that detects faults in any single switch or a pair of switches. The sparse matrix converter is functionally equivalent to the standard matrix converter but has a reduced number of switches. The proposed diagnostic method is based in the measurement of input and output currents. The currents have respective characteristic according to the location of faulty switches. This method not only detects the switches of open-circuit fault but identifies the location of the faulty switching devices without complicated calculations. The simulation and experimental results verify that, based on the proposed method, the fault of sparse matrix converter can be easily and fast detected.

• 전기학회논문지
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• 제58권8호
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• pp.1472-1478
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• 2009

The domestic power distribution system is operating in an open loop mode; however, it already has a loop structure. Power distribution systems must be changed for bi-directions power supply for smart networks due to a changing of paradigm in electric power industry. The simplest bi-directions distribution networks can make it closing of normally open switch. However, bi-directions power supply is very difficulty to be operated and there are many parts which it must study. This paper presented various models that are able to change a radial system for loop structures. Further, we compared the reliability index for each model by evaluating the amount of improvement reliability required in radial power distribution system. In addition, we calculated CIC(Customer Interruption Cost) for each model by comparing and analyzing.

• 전기학회논문지
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• 제56권5호
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• pp.821-828
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• 2007

This paper proposes a new algorithm to find optimal location of open switches connecting feeders in distribuion system. In order to enhance power system reliability by minimizing outage area in case of fault, the load balance among the facilities such as transformers and feeders is considered to optimize. The combination of optimal position of normal open switches can be found by moving tie along the direct path connecting two feeders related to the open switch while the whole optimization problem is separated into many small problems. The proposed algorithm is shown by case study results that, it is simple and takes short calculation time to apply to the DAS (Distribution Automation System) in KEPCO (Korea Electric Power Cooperation).