• 제목/요약/키워드: Jackknife estimator

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비모수적 회귀선추정의 바운더리 편의 수정 (Modification of boundary bias in nonparametric regression)

  • 차경준
    • 응용통계연구
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    • 제6권2호
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    • pp.329-339
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    • 1993
  • 커널을 이용한 회귀선의 추정은 단지 참 함수의 미분성만을 요구하는 비모수적인 회귀선의 추정방법이다. 유한구간에서 어떤 곡선의 완만한 추정곡선을 커널을 이용하여 추정할 때 추 정량의 전체적인 성능을 감소시키는 바운더리 문제가 발생하게 된다. 본논문에서는 바운더 리 문제를 다룰수 있는 커널을 개발하였다. Gray와 Schcany(1972)의 일반화된 jackknife 방 법을 이용하여 바운더리 커널을 개발하였고 또한 이 바운더리 커널이 이 바운더리 커널과 같은 수렴속도를 갖는 것을 보였다.

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계방산과 오대산 일대 분비나무 자생지 군집 구조 및 하층식생 특성 (Community Structure of Abies nephrolepis Habitats and Characteristics of Understory Vegetation in Mt. Gyebang and Mt. Odae)

  • 천광일;변준기;김정인;박병주
    • 한국환경복원기술학회지
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    • 제25권5호
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    • pp.59-76
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    • 2022
  • This study was conducted to investigated woody species community classification and understory vegetation characteristics of Abies nephrolepis forest in Mt. Gyebang and Mt. Odae designated as Protected Area for Forest Genetic Resource Conservation and National Park. Vascular plants were surveyed as following; 55 family, 148 species, 3 sub species, 14 variety, 2 form 167 taxa. As an analysis of the species estimator of Jackknife 1, 29 survey plots could be representative of vegetation in study site. Results of the woody species, 3 communities were divided by cluster analysis(A=Abies nephrolepis-Tilia amurensis, B=Betula ermanii-Abies nephrolepis, C=Quercus mongolica-Abies nephrolepis). Using MRPP-test, there were significant differences between the communities indicating analysis of the appropriate group classification(p<0.01). The basal area and altitude were analyzed by negative relationship for NMS ordination. By analyzing plexus diagram of woody species, Acer pseudosieboldianum is strong associated with Quercus mongolica and Rhododendron schlippenbachii. Magnolia sieboldii is strong associated with Acer pictum subsp. mono etc.

Species Diversity, Composition and Stand Structure of Tropical Deciduous Forests in Myanmar

  • Oo, Thaung Naing;Lee, Don Koo;Combalicer, Marilyn;Kyi, Yin Yin
    • 한국산림과학회지
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    • 제97권2호
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    • pp.171-180
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    • 2008
  • The characterization of tree species and forest stand conditions is useful in the planning of activities aimed to conserve biodiversity. The main objective of this study was to describe tree species diversity, species composition and stand structure of tropical deciduous forests distributed in three regions in Myanmar. Forest inventory was conducted in the Oktwin teak bearing forest, the Letpanpin community forest and Alaungdaw Kathapa National Park. According to the Jackknife estimator of species richness, 85 species (${\pm}18.16$), 70 species (${\pm}5.88$) and 186 species (${\pm}17.10$) belonging to 31 families were found in the Oktwin teak bearing forest, 33 families in Letpanpin community forest and 53 families in Alaungdaw Kathapa national park, respectively. Shannon's diversity indices were significantly different among the forests (p<0.05). It ranged from 3.36 to 4.36. Mean tree density (n/ha) of the Oktwin teak bearing forest, Letpanpin community forest and Alaungdaw Kathapa National Park were 488 (${\pm}18.6$), 535 (${\pm}15.6$) and 412 (${\pm}14.1$), while basal areas per hectare were $46.96m^2({\pm}3.23),\;49.01m^2({\pm}5.08)\;and\;60.03m^2({\pm}3.88)$, respectively. At the family level, Verbenaceae, Myrtaceae and Combretaceae occupied the highest importance value index, while at the species level it was Tectona grandis, Lagerstoremia speciosa and Xylia xylocarpa.