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목표물에 근접한 위치데이터를 사용한 2차원 위치추정방법
김덕기(Deokki Kim),김승열(Seung-Youl Kim),이상진(Sang-Jin Lee),유영갑(Younggap You) 한국콘텐츠학회 2010 한국콘텐츠학회논문지 Vol.10 No.1
본 논문에서는 목표의 위치를 결정하기 위해 사용되는 삼각법을 개선한 위치추정 방법을 제안한다. 제안하는 방법은 세 원간의 교점들을 통해 목표의 위치를 추정한다. 이 방법을 통해 결정된 목표의 위치는 기존의 방법과 같이 관측지역 중심에서 높은 정밀도를 갖고 기존의 방법에서 큰 오차를 갖는 관측지점 주변에서도 높은 정밀도를 갖는다. 이 방법은 기존의 방법보다 최대오차에서 40.89%, 평균오차에서 40.30%가 줄었다. This paper describes an improved location determination scheme based on the triangulation method calculating a target position. The proposed scheme uses coordinates of intersection points of three circles each generated by measurement of an observer. The target position obtained from the proposed scheme has higher accuracy not only at the vicinity, but also at the periphery of the observation area. The maximum error and the average error with the proposed scheme are reduced by 40.89% and 40.30%, respectively, with respect to conventional methods.
Dong-Hui Choi,Tae-Bok Ryu,DeokKi Kim,Dong-Eon Kim,Jung-Hyo Lee,Nam-Young Kim 강원대학교 산림과학연구소 2018 Journal of Forest Science Vol.34 No.4
The characteristics of 124 Phytolacca americana present areas and 88 surrounding absent areas over the country were investigated and compared from July 2016 to Sept 2017. The Phytolacca americana was confirmed as having been nationally distributed and is usually found in roadsides at an altitude of 380 m (26%), forest edges (24%), forests (19%), sunny spots (60%), dry soils (53%), sandy loams (31%) and sand+gravel soils (22%). 321 taxons consisting of 79 families, 209 genera, 289 species, 2 subspecies, 26 varieties and 4 cultivars and 286 taxons consisting of 76 families, 195 genera, 256 species, 2 subspecies, 24 varieties and 4 cultivars were found in the Phytolacca americana present areas and the absent areas, respectively. The relative net contribution degree was found highest in the Phytolacca americana (100) followed by Robinia pseudoacacia (29.4), Humulus japonicus (8.8) and Artemisia princeps (6.0) in the present areas, while it was found highest in Robinia pseudoacacia (100) followed by Humulus japonicus (44.4), Artemisia princeps (35.9), Pueraria lobata (18.6) and Setaria viridis (12.3) in the absent areas. The Raunkier’s life form in the present/absent areas was found highest in the therophytes (34%/34%), followed by hemicryptophytes (17%/18%), megaphanerophytes and mesophanerophytes (18%/17%), nanophanerophytes (11%/11%) and geophytes (9%/11%). There was no significant difference in the species diversity between the present (2.141) and the absent (2.124) areas. However, the allelopathic agent and light blocked-out by the Phytolacca americana could possibly inhibit germination and the development of other species; especially, where a difference in species diversity was found high in forests, compared to other habitats (p=0.0605). Accordingly, it is suggested to review possible disturbances of native species habitats in shady spots including forest gaps, although the effect of Phytolacca americana on the ecological system in the suburban open and disturbed areas is not large.
Choi, Dong-Hui,Ryu, Tae-Bok,Kim, DeokKi,Kim, Dong-Eon,Lee, Jung-Hyo,Kim, Nam-Young Institute of Forest Science 2018 Journal of Forest Science Vol.34 No.4
The characteristics of 124 Phytolacca americana present areas and 88 surrounding absent areas over the country were investigated and compared from July 2016 to Sept 2017. The Phytolacca americana was confirmed as having been nationally distributed and is usually found in roadsides at an altitude of 380 m (26%), forest edges (24%), forests (19%), sunny spots (60%), dry soils (53%), sandy loams (31%) and sand+gravel soils (22%). 321 taxons consisting of 79 families, 209 genera, 289 species, 2 subspecies, 26 varieties and 4 cultivars and 286 taxons consisting of 76 families, 195 genera, 256 species, 2 subspecies, 24 varieties and 4 cultivars were found in the Phytolacca americana present areas and the absent areas, respectively. The relative net contribution degree was found highest in the Phytolacca americana (100) followed by Robinia pseudoacacia (29.4), Humulus japonicus (8.8) and Artemisia princeps (6.0) in the present areas, while it was found highest in Robinia pseudoacacia (100) followed by Humulus japonicus (44.4), Artemisia princeps (35.9), Pueraria lobata (18.6) and Setaria viridis (12.3) in the absent areas. The Raunkier's life form in the present/absent areas was found highest in the therophytes (34%/34%), followed by hemicryptophytes (17%/18%), megaphanerophytes and mesophanerophytes (18%/17%), nanophanerophytes (11%/11%) and geophytes (9%/11%). There was no significant difference in the species diversity between the present (2.141) and the absent (2.124) areas. However, the allelopathic agent and light blocked-out by the Phytolacca americana could possibly inhibit germination and the development of other species; especially, where a difference in species diversity was found high in forests, compared to other habitats (p=0.0605). Accordingly, it is suggested to review possible disturbances of native species habitats in shady spots including forest gaps, although the effect of Phytolacca americana on the ecological system in the suburban open and disturbed areas is not large.
세이빙공구 상태 감시를 위한 베타분포모델에 기반한 특징 해석
최덕기(Deokki Choi),김성준(Seong-Jun Kim),오영탁(Young Tak Oh) 대한기계학회 2010 大韓機械學會論文集A Vol.34 No.1
공구상태 감시기술은 지능형 생산시스템 구축을 위하여 중요한 요소 기술이다. 다양한 생산 공정분야에 걸쳐 연구가 진행되었지만 기어 세이빙 공정에서 공구파손을 검출하는 연구가 발표된 바가 없다. 본 연구에서는 기어 세이빙 공정 중에 세이빙 공구의 상태를 검출하기 위하여 베타확률분포를 활용하는 통계적 기법을 제안하였다. 신뢰성 있는 공구상태 감시를 위하여 선행되어야 할 특징값 추출을 위하여 공정 중에 발생하는 진동 신호를 베타확률분포로 모델링하였다. 신호의 양봉 분포를 단봉 분포로 변환한 후 모멘트법을 사용하여 베타확률분포의 파라미터들을 추정함으로써 특징값들을 추출하였다. 특징값들의 유효성을 평가 결과, 베타분포 모델의 파라미터 중 모드가 우수한 세이빙 공구상태 감시 성능을 갖고 있음을 확인하였다. Tool condition monitoring (TCM) is crucial for improvement of productivity in manufacturing process. However, TCM techniques have not been applied to monitor tool failure in an industrial gear shaving application. Therefore, this work studied a statistical TCM method for monitoring gear shaving tool condition. The method modeled the vibration signal of the shaving process using beta probability distribution in order to extract the effective features for TCM. Modeling includes rectifying for converting a bi-modal distribution into a unimodal distribution, estimating the parameters of beta probability distribution based on method of moments. The performance of features obtained from the proposed method was evaluated and discussed.
최덕기(Deokki Choi),김용영(Yong young Kim),조동호(Dong Ho Cho) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.5
Net washing in the fishery requires a lot of labors as well as time and give rise to severe environmental pollution. This study developed the net hauler for washing which can haul and simultaneously wash the net. We devised the revolution body's structure of net hauler in order to resolve the net slip problem and added the washing function used as a main step in case of small-sized net or auxiliary step in case of large-sized net. Furthermore, the component installed for net unwrapping enables the net washing performance of automatic set-net washing machine to get higher. As a result of experiments using the prototypes of new net hauler, no net slips happened and the desirable washing performances could be achieved.
기어 세이빙 공정에서 베타 확률 분포를 이용한 공구 상태 검출
최덕기(Deokki Choi),김성준(Seong-Jun Kim),오영탁(Young Tak Oh) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
Tool condition monitoring (TCM) is crucial for improvement of productivity in manufacturing process. However, TCM techniques have not been applied to monitor tool failure in an industrial gear shaving application. Therefore, this work studied a statistical TCM method for monitoring gear shaving tool condition. The method modeled the shaving process using beta probability distribution in order to extract the effective features. Modeling includes rectifying for converting a bi-modal distribution into a unimodal distribution, estimating parameters of beta probability distribution based on method of moments. The usefulness of features obtained from the proposed method was evaluated and discussed.