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네트워크 이동성 지원을 위한 이동경로 예측 기반의 끊김없는 핸드오버 방안
박희동,권용하,이강원,최영수,조유제,조봉관,Park Hee-Dong,Kwon Yong-Ha,Lee Kang-Won,Choi Young-Soo,Cho You-Ze,Cho Bong-Kwan 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.7a
본 논문은 철도와 같은 이동 네트워크 환경에서 핸드오버로 인한 서비스 중단 시간 및 패킷 손실을 최소화하기 위하여 이동경로 예측 기반의 끊김없는 핸드오버 방안을 제안한다. 정해진 경로를 따라 이동하는 철도차량의 고유한 특징을 이용하여, 2계층 핸드오버를 수행하기 전에 미리 3 계층 핸드오버를 수행함으로써 핸드오버로 인한 서비스 단절과 패킷 손실을 최소화 시킬 수 있다. 성능평가 결과 제안된 방안은 기존 NEMO 방안에 비해 핸드오버 수행에 있어 우수한 성능을 나타냄을 알 수 있었다. This paper proposes a path prediction-based seamless handover scheme to minimize service disruption and packet loss due to handovers for mobile networks such as Dams. This scheme exploits a peculiar characteristics of trains which move on a predetermined path. The mobile router on the train can predict a handover point and then perform network-layer handover before link-layer handover occurs. This leads to the reduction of handover latency and packet loss during handovers. The performance evaluation showed that the proposed scheme could provide excellent performance, compared with the NEMO basic support scheme.
박희동(Hee-Dong Park) 한국산업정보학회 2008 한국산업정보학회논문지 Vol.13 No.5
본 논문은 Mobile IPv4에서 단말의 핸드오버 후 새로운 패킷 전달 경로는 이전의 패킷 전달경로와 같거나 유사할 확률이 높다는 사실을 이용하여 핸드오버 지연 및 시그널링 비용을 최소화하는 방안을 제안하였다. 제안 방안에서는 단말의 등록요청메시지를 수신한 외부 에이전트가 라우팅 비용을 이용하여 현재의 라우팅 경로와 이전 라우팅 경로의 상관성을 추정한다. 만약 현재의 라우팅 경로가 이전 경로와 같거나 유사하다면, 단말은 홈 에이전트 또는 상대노드로의 등록 과정 없이 이전의 외부에이전트로부터 패킷을 전달받게 된다. 성능 분석 결과 제안 방안은 기존의 핸드오버 및 경로 최적화 방안에 비해 지연 및 시그널링 비용을 효율적으로 감소시킬 수 있음을 확인할 수 있었다. This paper proposes a new handover scheme to minimize handover delay and signaling costs, using the fact that a new packet forwarding path could be same or similar to the old one in Mobile IPv4. In the proposed scheme a foreign agent estimates the correlation between the new and old routing paths by using routing costs after receiving a registration request message from a mobile node. If the new packet forwarding path could be same or similar to the old one, the mobile node can receive packets from its old foreign agent without registering its new location with its home agent or correspondent node. The performance analysis shows that the proposed scheme can efficiently reduce handover delay and signaling costs.
박희동(Hee-Dong Park),윤인식(In-Sik Yun),이원(Won Yi) Korean Society for Precision Engineering 2011 한국정밀공학회지 Vol.28 No.9
This research quantitatively confirmed an acoustical anisotropy that exists in a pure titanium plate from the signal of ultrasonic flow detection and suggested a new way to evaluate the acoustical anisotropy by inputting acquired characteristic of ultrasound signal into the neutral network. Using the fact with the suggested method that the characteristic of ultrasound signal is shown differently depending on the pure titanium plate's rolling direction, the neural network was constructed by extracting the characteristic that can decide each direction of 0°, 45°, and 90° with waveform analysis program. As a result of inputting the characteristic of ultrasound signal acquired from a random rolling direction into the neural network that was built like this, it showed a pattern recognition rate higher than 95% on directions of 0°, 45°, 90°.
음향 이방성을 고려한 티타늄 용접부의 결함길이 측정에 관한 연구
박희동(Hee-Dong Park),윤인식(In-Sik Yun),이원(Won Yi) Korean Society for Precision Engineering 2011 한국정밀공학회지 Vol.28 No.9
This study intends to assess the defect in the weld zone of titanium grade 2 plate in terms of acoustical anisotropy based on the angle beam method. Depending on the rolling direction, the ratio of wave velocity was found to be 1.08 and the difference in the angle of refraction was more than seven degrees, confirming the presence of acoustical anisotropy. Thus for measuring the length of defect in the weld zone of the titanium plate (thickness of 10㎜), the distance amplitude characteristics curves of titanium, TDACC-R and TDACC-T were constructed for the measurements in consideration of the acoustical anisotropy on CRT of the ultrasonic testing equipment. As a result, when the distance amplitude characteristics curve corresponds to the rolling direction, the length of defect was close to the actual measurement within 1mm and when different, the difference was found to be over 4mm. It was affirmed that the acoustical anisotropy should be taken into consideration when measuring the length of defects in the weld zone of the titanium plate with the presence of acoustical anisotropy.
中ㆍ小規模 建築 設計 事務所의 受注 戰略에 따른 經營 方式 硏究
박희동(Park Hee-Dong),홍영균(Hong Young-Kyun) 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2
It is true that the role of a small & medium construction & design companies renders great service not only to national economy but also to korean construction business both of directly and indirectly. On the contrary, economical condition of employees who work in a small & medium construction & design company is greatly poor, and it is not too much to say that it made companies lo be faced la the question of maintenance or abolition.<br/> According to the data from interviews with present architect and advice of experts, I found that we need aggressive sales of policies, positive way of thinking, prominent skills from continuous effort, scout experts in management, establishment of field of expert in design, professional thinking as an expert to get continuous high valued design service orders. I expect that the small & medium construction & design companies could get better condition as they apply this study to their business.