• 반도체디스플레이기술학회지
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• 제20권4호
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• pp.108-113
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• 2021

In this paper, a totem pole PFC was structured in two methods with FET and diode for low-speed switch while GaN FET was used for high-speed switch. Internal power loss, power conversion efficiency and steady-state characteristics of the two methods were compared in the totem pole bridgeless PFC circuit which is widely applied in large-capacity and high-efficiency switching rectifier of 500W or more. In order to compare and confirm the steady-state characteristics under equal conditions, a 2kW class totem pole bridgeless PFC was constructed and the experimental results were analyzed. From the experimental results, it was confirmed that the low-speed switch operation has a large difference in efficiency due to the internal conduction loss of the low-speed switch at a low input voltage. Especially, input power factor and load characteristic showed no difference regardless of the low-speed switch operation.

• 한국전자파학회논문지
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• 제16권2호
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• pp.167-173
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• 2005

직렬 PIN 다이오드 스위치의 격리도는 PIN 다이오드의 병렬 커패시턴스에 의해 제한을 받으며, 스위치 구동회로는 PIN 다이오드 스위치의 스위칭 속도를 제한한다. 이런 문제를 극복하기 위해, 병렬 공진 인턱턴스와 TTL 호환의 스위치 구동회로가 적용된 높은 격리도와 고속 스위칭의 PIN 다이오드 스위치를 제안하였다. 3 GHz PIN 다이오드 스위치의 측정 결과, 1 GHz의 주파수 대역폭, 1.5 dB 이내의 삽입 손실, 65 dB의 격리도, 15 dB 이상의 반사 손실 그리고 30 ns 이내의 스위칭 속도를 나타내었다. 특히, 병렬 공진 인덕턴스를 사용한 3 GHz스위치는 15 dB의 격리도 향상을 나타내었다.

• 인터넷정보학회논문지
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• 제9권2호
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• pp.15-23
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• 2008

본 논문에서는 고효율을 유지하며 QoS를 보장하는 새로운 구조의 다중 입출력 버퍼링 방식의 스위치와 이 스위치에서 사용되는 새로운 중재 알고리즘인 Anti-Empty 알고리즘을 제안한다. 새로운 스위치 구조는 MIQ와 MOQ를 기본으로 하여 외부회선 속도와 동일한 속도를 가지는 버퍼를 사용하는 구조로 설계되었으며 기존 방식의 단점을 제거하고 QoS를 지원하기 위해 MOQ의 동작 방법에 새로운 방식을 도입하였다. 이로서 스위치 전체의 수율과 지연 등의 성능이 고 효율의 출력 버퍼형 스위치와 동일하면서 셀 손실이 없는 QoS를 지원하는 고속 스위칭을 보장한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1946-1950
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• 2007

Switch rail is a very important part on the railway track, which not only accounts for the safety of the passing trains but also greatly influences the speed of the train. The higher the speed and the loads of the train the more it demands on the properties of the switch rail. Research shows that the higher mechanical properties of switch rail the longer the service life. Induction heat treatment is a good way of improving the mechanical properties of metallic materials. But the switch rail's section area changes gradually across the lengthways, which is difficult for induction heating especially for the small section. And the mechanical property of small section of the switch rail is the most important for its service life. The induction heat treatment used past always brings the low hardness on small section which can cause low service life of switch for wearing, or too high hardness because of martensite microstructure which can cause the shelling or even breaking of the switch rail. To prolong the service life of switch rail by higher mechanical properties, we researched the improved induction heat treatment for switch rail by adjusting speed of heating, and adopting compressed air cooling. The results showed that switch rail obtain almost the same high hardness across the length way after the improved induction heat treatment, which is very helpful to extend the service life of switch rail.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.966-968
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• 2005

Generally the high-voltage and high-current making switch is used to test the short-circuit test. The making switch should be operated always same speed/time and kept electrical-mechanical characteristic. There are spring charge type, hydro-pneumatic type and compressed air type etc. according to operation method of making switch contacts. Especially the making switch contacts of hydro-pneumatic type are moved by actuator and accumulator. To keep same speed/time of contacts and characteristic of making switch, actuator and accumulator should be worked always uniformly. So the dynamic analysis of actuator and accumulator of hydro-pneumatic type making switch will be helpful to maintain and design.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 하계종합학술대회 논문집
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• pp.122-125
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• 1999

In this paper, we propose a new architecture of the Banyan switch for a high speed networking and the high speed parallel computer. The proposed switching network with a remodeled architecture is a newly modified Banyan network with eight input and output pots, respectively. We have analysed the maximum throughput of the revised switch. Our analyses has shown that under the uniform random traffic load, the FIFO discipline is limited to 70％. Therefore the result of the analyses shows that the results of the networking simulation with the new switch are feasible and if we adopt such as new architecture of the revised model of the Banyan switch, the hardware complexity can be reduced. The FIFO discipline has increased about 11% when we compare the switching system with the input buffer system. We have designed and verified the new switching system in VHDL.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.537-540
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• 2000

In this paper, we propose and design new architecture of the modified Banyan switch for a high speed networking and the high speed parallel computer. The proposed switching network with a remodeled architecture is a newly modified Banyan network with eight input and output ports. The switch scheme is that two packets may arrive on different inputs destined for the same output. We have analyzed the maximum throughput of the revised switch. The result of the analyses shows good agreement simulation and if we adopt such architecture of the revised model of the Banyan switch, the hardware complexity can be reduced. The FIFO discipline has increased about lloio when we compare the switching system with the input buffer system. We have designed and verified the switching system in VHDL.

• 환경영향평가
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• 제15권6호
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• pp.453-458
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• 2006

A turnout system which permits trains to pass from one track to another consists of the switch, the crossing, lead rails which are necessary to connect the switch and the crossing, two guard rails and a switch machine for operating the switch. A turnout is the sole moving part among the railway components and has complex configuration, so the safety has always been raised an issue. In Korea, it is planned to adopt the high speed tilting train, which operates at the maximum speed of 180km/h, at conventional lines by the year of 2010. However, for the application of the tilting train to conventional lines, it is prerequisite to establish a stable turnout system allowing the tilting train to pass through it without reducing speed. Therefore, the improved turnout system for the speed-up of conventional lines has been developed and the prototype of the turnout system has been constructed. In this study, evaluation of noise characteristics around the improved turnout system was performed through the field measurements. Field measurements of noise around the conventional and the high-speed turnout system were also carried out for the comparison.

• 한국통신학회논문지
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• 제24권8B호
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• pp.1401-1411
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• 1999

멀티미디어 서비스의 증가에 따라 멀티캐스팅(Multicasting)은 ATM 스위치 디자인에 있어 중요성을 더해가고 있다. 기존의 다단 연결 구조에서 멀티캐스트에 의한 트래픽 팽창의 문제를 해결하기 위해 본 논문에서는 고속의 버스와 공유 메모리 스위치를 이용한 멀티캐스트 스위치를 제안한다. 고속의 시분할 버스를 연결 매체로 사용하며 공유 메모리 스위치를 단위 모듈로 하는 구조를 채택하여 용이한 포트 확장성을 제공한다. 트래픽 중재 기법을 사용하여 내부 블러킹을 없애며, 시뮬레이션을 통해 데이터 처리율이나 셀지연 측면에서의 스위치 성능을 확인한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.369-372
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• 2001

This paper presents the design of high-speed virtual output queue(VOQ) management scheme for high performance cell/packet switch, which has a serial cross bar structure. The proposed VOQ management scheme has been designed for wire-speed routing with a pipelined buffer management. It provides the tolerance of requests and grants data transmission latency between the VOQ manager and central arbiter using a new request control method that is based on a high-speed shifter. The designed VOQ manager has been implemented in a field programmable gate array chip with a 77MHz operating frequency, a 900-pin fine ball grid array package, and 16$\times$16 switch size.