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핸드오버 지연 시간을 줄일 수 있는 심리스 핸드오버 프로토콜 제안 및 성능 분석
장종민,이유태,이숭희,김동일,최삼길,Jang, Jong-Min,Lee, Yu-Tae,Lee, Soong-Hee,Kim, Dong-Il,Choi, Sam-Gil 한국정보통신학회 2009 한국정보통신학회논문지 Vol.13 No.2
With significant development in wireless communication technologies, the needs to handover from one network to another have grown dramatically. Recently IETF developed MIPv6 and FMIPv6 which are used to handover between different access networks. These handover mechanisms have some known weaknesses. MIPv6 can not serve time-critical application because it causes long handover latency and packet loss. By these reasons, MIPv6 does not guarantee session continuity. FMIPv6 uses handover preparation phase to reduce DAD latency. However FMIPv66 still suffers from long handover latency, because it must perform binding update at the end of handover procedure. In this paper we propose new handover mechanism FMIPv6-PBU which eliminates binding update latency. The proposed mechanism has compatability with lagacy FMIPv6. In this paper propose FMIPv6-PBU handover procedure and explain its procedures and evaluate it with MIPv6 and FMIPv6. 무선 이동 통신기술과 이동 단말의 발달로 이종망간 핸드오버에 대한 요구가 증가하고 있다. IETF는 All-IP 기반 네트워크에서 이종 엑세스 네트워크 사이의 핸드오버를 위한 표준을 정의하는 MIPv6와 FMIPv6를 개발하였다. MIPv6는 단말의 핸드오버가 수행되는 동안 긴 지연 시간과 패킷 손실을 유발함으로써 시간에 민감한 서비스의 세션 연속성을 보장하지 못했다. FMIPv6는 핸드오버 준비 과정에서 주소를 미리 구성하고 엑세스 라우터가 패킷을 버퍼링 하도록 함으로써 패킷 손실의 가능성을 줄였다. 그러나 FMIPv6는 여전히 핸드오버의 마지막 과정으로 바인딩 갱신을 수행해야 하는데, 이로 인한 지연 시간은 실시간 애플리케이션에 지연을 유발한다. 본 논문에서는 FMIPv6와 호환가능하며 바인딩 갱신에 필요한 시간을 줄일 수 있는 새로운 프로토콜을 제안하고, 성능분석을 통해 기존 프로토콜의 핸드오버 지연시간과 비교한다.
Cu계 금속을 용사한 콘크리트 벽체의 전자파 차폐 성능에 관한 연구
장종민 ( Jang Jong-min ),이한승 ( Lee Han-seung ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.2
The ElectroMagnetic Pulse (EMP) destroys social infrastructure at once and causes social chaos. However, currently major infrastructures are constructed of concrete that does not have electromagnetic shielding performance. In this study, using the arc metal spraying method is used to evaluate the shielding performance and construction performance of concrete. The electro-magnetic shielding effect is measured by fabricating a shielding room with reference to MIL-STD-188-125, and the construction performance is evaluated by measuring the adhesion strength of thin metal sprayed film-concrete. As a result of the study, when the metal spraying method is applied, the shielding effect is higher than that of the special electro-magnetic shielding concrete, and it is considered to be more economical than the existing metal plate (3~5 mm).
금속 용사 피막의 전기전도도 및 전자파 차폐 특성에 관한 연구
장종민 ( Jang Jong-min ),이한승 ( Lee Han-seung ) 한국건축시공학회 2020 한국건축시공학회 학술발표대회 논문집 Vol.20 No.1
In this study, the electrical conductivity and shielding effect were evaluated according to the type of metal and the thickness of Metal sprayed coating. The metals used for the test are Cu, Cu-Ni and Cu-Zn, and the thicknesses were 100, 200, 500 um. Each metal sprayed coating was evaluated for electrical conductivity and electromagnetic shielding effect. When the thickness was 200 μm or more, shielding effect 80 dB or more was satisfied at 1 GHz. However, in the case of Cu-Ni, there is little electrical conductivity at a thickness of 100 um or less due to the generated voids, and electromagnetic wave shielding performance cannot be expected. Therefore, To ensure electromagnetic shielding effect of structures, it is considered that the minimum thickness of metal spraying coating should be 200 um.
상대밀도를 고려한 시멘트 페이스트 압축 강도에 관한 실험적 연구
장종민 ( Jang Jong-min ),장현오 ( Jang Hyun-o ),이한승 ( Lee Han-seun ) 한국건축시공학회 2017 한국건축시공학회 학술발표대회 논문집 Vol.17 No.1
In In this study, we measured the relative density and the compressive strength in order to select the appropriate W/B for the ultra-high strength concrete development. If W/B is lowered than the W/B of highest relative density, it was confirmed that the strength is lowered. However, if water is increased than the W/B, the relative density is decreased compressive strength was similar. The selection of the W/B of the lower than the highest relative density is not appropriate. Appropriate W/B is selected to be more than the maximum relative density of W/B. This was confirmed for TG-DTA.