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무선 센서망에서의 사후 무선동기 기반 능동형 단반향 거리추정 방식
남윤석,배병철,Nam, Yoon-Seok,Bae, Byoung-Chul 대한임베디드공학회 2010 대한임베디드공학회논문지 Vol.5 No.4
Two-way ranging methods such as TWR and SDS-TWR have been considered for many ranging systems because these methods are useful in the absence of synchronization. To estimate the location of a mobile node, complicated ranging procedures consisting of ranging frames between an anchor node and the mobile node are performed. Supporting multiple mobile nodes such as a few hundreds or thousands and several anchor nodes, the ranging procedures have the fatal disadvantage of processing delay and inefficient traffic bandwidth. On the other hand, the one-way ranging method is simple and fast, but susceptible to network synchronization. In this paper, we propose a method to modify asynchronous ranging equations to establish exact frequency or frequency offset, a method to estimate frequencies or frequency offsets, and a method to establish post-facto synchronization with anchor nodes. The synchronization for a node pair is adapted using instantaneous time information and corresponding difference of distances can be determined. We evaluate the performance of TWR, SDS-TWR and proposed ranging algorithms.
무선 센서망에서 주파수 편이 보상 비동기 양방향 거리추정 알고리즘
남윤석,허재두 에스케이텔레콤 (주) 2009 Telecommunications Review Vol.19 No.5
무선 센서망에서는 해상도가 높은 UWB 신호를 사용하여 노드간의 거리를 추정하고 이로부터 이동 노드의 위치를 추정한다. IEEE802.15.4a에서는 각 노드 국부클럭의 주파수 차이에 의한 영향을 감소시키는 비동기 TWR 및 SDSTWR 거리 추정방식을 제안하고 있으나 이들 방식은 불완전한 동기화에 의한 오류를 감소시킬 뿐이며 주파수 편이는 여전히 시각 측정 오류를 유발한다. 따라서 노드의 클럭 주파수 편이는 정확한 거리 추정의 핵심이다. 본 논문에서는 노드의 주파수 편이 추정 기반의 새로운 거리 추정방식을 제안한다. 제안된 방식은 모사시험으로 성능을 평가하였으 며 평가 결과로부터 제안된 방식은 모사시험 환경에서 노드의 주파수 편이, 거리추정 프레임의 전송지연 그리고 지연 의 차이에 거의 영향을 받지 않으며 이동 노드의 정확한 위치를 추정하는 것을 확인하였다.
양이온성 지방산아민 벌키화제를 이용한 저밀도 종이 제조 (2) -BCTMP 수초지 특성에 미치는 영향-
남윤석,최경화,조준형 한국펄프·종이공학회 2015 펄프.종이技術 Vol.39 No.3
In this study, the effects of cationic fatty acid bulky promotor on the properties of BCTMP (bleached chemithermomechnical pulp) handsheet including bulk and strength were elucidated. As results, it was observed that the bulk of BCTMP handsheet increased with the increases of the concentration of cationic fatty acid bulky agent, while mechanical properties such as tensile strength and burst strength decreased. The opacity of BCTMP handsheet also increased with the increases of the concentration of cationic fatty acid bulky agent, while brightness was almost not changed. The effectiveness of bulky agent with SwBCTMP (softwood) was higher than that with HwBCTMP (hardwood). Compared with previous research on the effect of bulky agent on BKP handsheet, the bulk increase of BCTMP handsheet was greater compared to that of BKP handsheet. However, the reduction of mechanical property in BCTMP handsheet was lower than that of BKP handsheet.
양이온성 지방산아민 벌키화제를 이용한 저밀도 종이 제조 (1) - 처리제 농도 및 펄프 수종이 미치는 영향 -
남윤석,조준형,최경화,김해란 한국펄프·종이공학회 2014 펄프.종이技術 Vol.34 No.4
As a part of the study on manufacture of low density paper by organic bulky agent treatment, the effectsof cationic fatty acid bulky agent on physical and optical properties of handsheets were elucidated. Theresearch on change of physical and optical properties of paper samples according to bulky agent concentration,pulp type, and pulp combination were carried out. The results demonstrated that an increase ofthe concentration of cationic fatty acid bulky agent was proportional to an increase of the bulky propertiesof paper samples while tensile strength decreased. Also, the more the treated concentration of cationicfatty acid bulky agent increased, the more the ISO brightness of paper samples decreased while the opacityincreased. The effectiveness of bulky agent with softwood bleached kraft pulp (SwBKP) was higherthan that with hardwood bleached kraft pulp (HwBKP). In addition, the effectiveness with mixed pulpswas higher than that with single pulp.