• Title/Summary/Keyword: 형태 변이

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가변하중을 받는 구조물의 피로 해석 및 시험

  • 이장무
    • Journal of the KSME
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    • v.16 no.4
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    • pp.12-18
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    • 1976
  • 기계 및 구조물들이 등진폭하중만을 받는 경우는 극히 드물어서 대부분이 진폭과 주파수가 불규 칙하게 변하는 하중을 받는다. 실하중이력이 불규칙(random)한 모양을 갖는 것은 비행기, 자동차, 선박 등의 많은 기구물들이 공기의 터블런스, 거치론 도로표면 및 대양의 파도와 같이 random한 주위환경에 접하기 때문이다. 이 random한 환경과 구조물의 탄성성질들로 인해서 구조물로부터 측정된 하중응답신호들(응신율,변위 혹은 가속도)은 건폭과 주파수가 random하게 변하는 특정한 형태의 파형을 갖는다. 현금 우리나라에 이 방면의 연구가 활발하지 못하여 complex load history가 피로에 미치는 영향과 이에 관련된 피로시험들을 간략히 소개한다.

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Learning Action Selection ,Network Using Learning Classifier System (Learning Classifier System을 이용한 행동 선택 네트워크의 학습)

  • 윤은경;조성배
    • Proceedings of the Korean Information Science Society Conference
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    • 2003.04c
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    • pp.404-406
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    • 2003
  • 행동 기반 인공지능은 기본 행동들의 집합으로부터 적절한 행동을 선택함으로써 복잡한 행동을 하도록 하는 방식이다. 행동 기반 시스템은 1980년대에 시작되어 이제는 많은 에이전트 시스템에 사용되고 있다. 본 논문에서는 기존의 P. Maes가 제안한 행동 선택 네트워크에 Learning Classifier System을 이용한 학습 기능을 부가하여, 변하는 환경에 적절히 적응하여 행동의 시퀀스를 생성할 수 있는 방법을 제안하다. 행동 선택 네트워크는 주어진 문제에 따라 노드 간 연결을 설계자가 미리 설정하도록 하는데, 해결해야 할 문제가 변함에 따라 네트워크에서의 연결 형태가 변형될 필요가 있다. Khepera 로봇을 이용한 시뮬레이션 결과, 행동 선택 네트워크에서의 학습이 유용함을 확인할 수 있었다.

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Morphological Variation in Polygonum setaceum (Polygonaceae) (여뀌과 식물 Polygonum setaceum의 형태적 변이)

  • 박종욱
    • Journal of Plant Biology
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    • v.34 no.3
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    • pp.177-183
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    • 1991
  • Patterns of morphological variation in Polygonum setaceum Baldwin ex Elliott are examined, and the taxonomic significance of the varieties recognized by Fernald is reevaluated. The diagnostic characters used to differentiate the varieties in P. setaceum demonstrate virtually continuous variation, and broad geographic intergradation is recognized. Principal components analyses of major morphological characters also fail to separate the varieties. These results strongly suggest that recognition of var. setaceum, var. interjectum, and var. tonsum by Fernald is unwarranted.

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A Nonlinear Three-dimensional Spectral Model Using Similarity Transform Technique (유사변환 기법을 이용한 비선형 3차원 모델의 개발)

  • 강관수;정경태;소재귀
    • Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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    • 1993.07a
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    • pp.178-182
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    • 1993
  • 유속의 연직분포를 알기 위한 방안의 하나로 Galerkin 함수 전개모델에 대한 연구가 활발히 진행되어 왔다(Heaps, 1972; Davies, 1980; Cordon,1982; 최,1983;강등,1993). Galerkin 함수 이용 3차원 모델은 수직좌표상의 수평유속 성분을 수평좌표, 시간에 따라 변하는 계수 와 수심에 따라 변하는 함수군의 곱의 형태로 선형전개하며, 계수의 값은 Galerkin 방법을 써서구한다. (중략)

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In vitro propagation of oil palm (Elaeis guineensis Jacq.) clones through somatic embryogenesis and analysis of somaclonal variation by RAPD (체세포배발생을 통한 오일팜나무(Elaeis guineensis Jacq.) 클론의 기내증식 및 RAPD를 이용한 체세포변이의 검정)

  • Ahn, In-Suk;Park, Hye-Rim;Son, Sung-Ho
    • Journal of Plant Biotechnology
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    • v.39 no.3
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    • pp.196-204
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    • 2012
  • This study was carried out to develop reliable systems for somatic embryogenesis in oil palm tree (Elaeis guineensis Jacq.), and to verify the somaclonal variants by RAPD analysis. Embryogenic callus was induced successfully on modified half-strength MS medium containing $NaH_2PO_4{\cdot}2H_2O$ and casein. Embryogenic callus was further developed to somatic embryo mass (SEM), which is very hard and bonded tightly each other. Plantlets were proliferated when SEM was cultured on modified MS medium containing half strength $NH_4NO_3$, casein and L-ascorbic acid. Plantlets were transplanted into pots containing artificial soils. When RAPD analysis was conducted using randomly selected 95 in vitro plantlets and 19 random primers, somaclonal variation was detected using BNR35 primer. There was missing band around 1 kb in #22, #28, #35, and #77 plantlets. In addition, bands obtained from #28, #35, and #77 was much stronger than other normal bands. The blast results at NCBI revealed that somaclonal variation observed in this study was related to chloroplast genome of oil palm. The results also revealed that oil palm reproduction system through somatic embryogenesis is quite reliable and early detection of somaclonal variants seem to be possible at in vitro stage by RAPD analysis.

세계과학기술 향후 30년을 전망한다

  • Korean Federation of Science and Technology Societies
    • The Science & Technology
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    • v.30 no.5 s.336
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    • pp.43-69
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    • 1997
  • 앞으로 30년, 2020년대 말쯤 우리의 삶은 어떤 형태로 변해갈까. 우리나라 현대과학기술 역사 30년을 맞아 세계 과학기술 향후 30년을 진단해 보았다.

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Evaluation of Crop Characteristics of Sorghum (Sorghum bicolor L.) Germplasm for the Selection of Excellent Resources (우수자원 선발을 위한 수수(Sorghum bicolor L.) 유전자원의 특성평가)

  • Yoon, Seong-Tak;Jeong, In-Ho;Han, Tae-Kyu;Kim, Young-Jung;Yu, Je-Bin;Yang, Gyeong;Ye, Min-Hee;Baek, Seung-Woo;Kim, Kun-Woo
    • Korean Journal of Plant Resources
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    • v.29 no.4
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    • pp.479-494
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    • 2016
  • The aim of this study is to select the superior resources of high yield, high content of functional material optimal to mechanical harvesting by the evaluation of crop growth and yield characteristics in sorghum germplasm. One hundred accessions of sorghum germplasm were used in this experiment. Days from seeding to heading date showed the range from 68 to 94 days with the highest frequency proportion was the group from 80 to 85 days, which occupied 34% (34 plant resources) of 100 germplasm. Ear types of 100 sorghum germplasm could be classified as 7 types of broom-tillering, half broom-tillering, extreme open-loose type, open-loose type, intermediate type, compact type, extreme-compact type of which intermediate type was the highest ratio of 28% (28 plant resources) of 100 germplasm. Yield showed the range from 106 to 365 ㎏/10a with the highest frequency proportion of it was the group from 150 to 200 ㎏/10a, which occupied 44% (44 plant resources) of 100 germplasm. Among 100 sorghum germplasm, 18 ideal resources of high yield and short plant height appropriate for mechanical harvesting were selected. In order to evaluate high content of functional substance, selected 18 resources were analyzed for total polyphenol content, DPPH radical scavenging activity and total anthocyanin content. Finally, we selected 5 resources of short plant height, high yield, high content of total polyphenol and high DPPH radical scavenging activity among 18 genetic resources.

Taxonomic Study on Cirsium Miller (Asteraceae) in Korea Based on External Morphology (외부형태형질에 의한 한국산 엉겅튀속(Cirsium Miller)의 분류학적 연구)

  • Song, Mi-Jang;Kim, Hyun
    • Korean Journal of Plant Taxonomy
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    • v.37 no.1
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    • pp.17-40
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    • 2007
  • Patterns of morphological variation in Korean Cirsium were examined using numerical analysis, and the delimitation of taxa was evaluated. Principal components analysis of individuals of taxa using 61 morphological characters revealed the presence of two major groups. One group included C. lineare, C. vlassovianum, and C. setidens, the other contained C. pendulum, C. japonicum var. japonicum, C. japonicum var. spinosissimum, C. schantarense, C. nipponicum, and C. rhiniceros. Also, the result of cluster analysis recognized three sections, Onotrophe, Pseudo-eriolepis, and spanioptilon. Korean Cirsium was classified into three sections; C. japonicum var. japonicum, C. japonicum var. spinosissimum, C. schantarense, C. rhiniceros and C. nipponicum were belonged to sect. Onotrophe, C. setidens, C. vlassovianum and C. lineare were belonged to sect. Spanioptilon, and C. pendulum was belonged to sect. Pseudo-eriolepis. In conclusion, Korean Cirsium was classified into three sections, eight species, three varieties, and five forms.