• The Journal of Information Systems
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• v.17 no.3
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• pp.25-37
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• 2008

In a fault tree analysis, an uncertainty importance measure is often used to assess how much uncertainty of the top event probability (Q) is attributable to the uncertainty of a basic event probability ($q_i$), and thus, to identify those basic events whose uncertainties need to be reduced to effectively reduce the uncertainty of Q. For evaluating the measures suggested by many authors which assess a percentage change in the variance V of Q with respect to unit percentage change in the variance $v_i$ of $q_i$, V and ${\partial}V/{\partial}v_i$ need to be estimated analytically or by Monte Carlo simulation. However, it is very complicated to analytically compute V and ${\partial}V/{\partial}v_i$ for large-sized fault trees, and difficult to estimate them in a robust manner by Monte Carlo simulation. In this paper, we propose a method for evaluating the measure using discretization technique and Monte Carlo simulation. The proposed method provides a stable uncertainty importance of each basic event.

• Journal of Ecology and Environment
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• v.35 no.2
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• pp.91-98
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• 2012

This study was performed in order to suggest the possibility of tree species classification using high-resolution QuickBird-2 images spectral characteristics comparison(digital numbers [DNs]) of tree species, tree species classification, and accuracy verification. In October 2010, the tree species of three conifers and eight broad-leaved trees were examined in the areas studied. The spectral characteristics of each species were observed, and the study area was classified by image classification. The results were as follows: Panchromatic and multi-spectral band 4 was found to be useful for tree species classification. DNs values of conifers were lower than broad-leaved trees. Vegetation indices such as normalized difference vegetation index (NDVI), soil brightness index (SBI), green vegetation index (GVI) and Biband showed similar patterns to band 4 and panchromatic (PAN); Tukey's multiple comparison test was significant among tree species. However, tree species within the same genus, such as $Pinus$ $densiflora-P.$ $rigida$ and $Quercus$ $mongolica-Q.$ $serrata$, showed similar DNs patterns and, therefore, supervised classification results were difficult to distinguish within the same genus; Random selection of validation pixels showed an overall classification accuracy of 74.1% and Kappa coefficient was 70.6%. The classification accuracy of $Pterocarya$ $stenoptera$, 89.5%, was found to be the highest. The classification accuracy of broad-leaved trees was lower than expected, ranging from 47.9% to 88.9%. $P.$ $densiflora-P.$ $rigida$ and $Q.$ $mongolica-Q.$ $serrata$ were classified as the same species because they did not show significant differences in terms of spectral patterns.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.5
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• pp.187-195
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• 2009

In a fault tree analysis, an uncertainty importance measure is often used to assess how much uncertainty of the top event probability (Q) is attributable to the uncertainty of a basic event probability ($q_i$), and thus, to identify those basic events whose uncertainties need to be reduced to effectively reduce the uncertainty of Q. For evaluating the measures suggested by many authors which assess a percentage change in the variance V of Q with respect to unit percentage change in the variance $\upsilon_i$ of $q_i$, V and ${\partial}V/{\partial}{\upsilon}_i$ need to be estimated analytically or by Monte Carlo simulation. However, it is very complicated to analytically compute V and ${\partial}V/{\partial}{\upsilon}_i$ for large-sized fault trees, and difficult to estimate them in a robust manner by Monte Carlo simulation. In this paper, we propose a method for experimentally evaluating the measure using a Taguchi orthogonal array. The proposed method is very computationally efficient compared to the method based on Monte Carlo simulation, and provides a stable uncertainty importance of each basic event.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.234-238
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• 1999

The correlation between shape of electrical trees and partial discharge(PD) pulses in low density polyethylene(LDPE) were discussed. We observed growth feature of electrical tree by using optical microscope. On the basis of experimental results of measurements of trees occurring in the needle-plane arrangement with needle shape void and without needle shape void , statistical quantities are derived, which are relevant to PD pulse amplitude and phase. The PD quantities detected by partial discharge detector. we were analyzed q-n distribution pattern and $\psi$ -q-n distribution pattern. In this experiment, electrical trees in the needle-plane arrangement with needle shape void propagated branch type tree and in the needle-plane arrangement without needle shape void propagated bush type tree

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2396-2398
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• 1999

In this paper, inception and propagation of electrical tree and properties of partial discharge (PD) properties accompanying with tree in XLPE were discussed. The process of electrical tree using CCD camera and investigated the statistical characteristics of the PD properties by $\phi$-q-n pattern were observed. The statistical operators used were asymmetry and skewness.

• Journal of Korean Society of Forest Science
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• v.111 no.3
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• pp.365-373
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• 2022

We compared carbon stocks in tree biomass and soils of Quercus acutissima, Q. mongolica, Q. serrata, and Q. variabilis stands. A total of 531 plots (Q. acutissima: 110 plots, Q. mongolica: 177 plots, Q. serrata: 96 plots, Q. variabilis: 148 plots) were examined between 2016 and 2021 to determine the tree biomass and soil carbon stocks throughout the country. The carbon stocks of tree biomass were significantly higher in Q. mongolica (mean stand age, 57 years, 144.9 Mg C ha^-1) than in Q. variabilis (mean stand age, 43 years, 123.7 Mg C ha^-1), Q. serrata (mean stand age, 43 years, 120.1 Mg C ha^-1), and Q. acutissima (mean stand age, 36 years, 113.2 Mg C ha^-1) stands. The soil carbon concentration was significantly higher in Q. mongolica (A: 43.1 mg C g-1) than in Q. serrata (31.0 mg C g-1), Q. variabilis (25.31 mg C g-1), and Q. acutissima (24.4 mg C g-1) stands. The soil carbon stocks were significantly higher in Q. mongolica (116.8 Mg C ha^-1) than in Q. acutissima (49.3 Mg C ha^-1) stands. Total carbon stocks of tree biomass and soil were highest in Q. mongolica (262 Mg C ha^-1), followed by Q. serrata (218 Mg C ha^-1), Q. variabilis (211 Mg C ha^-1), and Q. acutissima (163 Mg C ha^-1) stands. Multiple linear regressions were performed to estimate the total carbon stocks of the four Quercus spp., and results showed that total carbon stocks increased with increasing elevation, mean diameter at breast height, and basal areas. Basal area and elevation of Quercus spp. stands were important explanatory variables based on multiple linear regressions for estimating carbon stocks.

• The Korean Journal of Ecology
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• v.26 no.4
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• pp.155-163
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• 2003

In order to analyze the succession process from a pine forest to an oak forest, the tree growth of Pinus densiflora and Quercus mongolica ssp. crispula was monitored in a permanent quadrat for 23 years. The measurements were carried out for the stem diameter (DBH) of Pinus densiflora between 1977 and 1999 and for the height of Quercus mongolica ssp. crispula saplings between 1998 and 2000. The floristic composition and the locations of the individual P. densiflora and Q. mongolica ssp. crispula trees and saplings in the quadrat were recorded. P densiflora and Q. mongolica ssp. crispula individuals were randomly distributed within the quadrat. The relative growth rates (RGR) of DBH in P. densiflora were 0.085 $yr^{-1}$ for large trees and 0.056 $yr^{-1}$ for small trees in 1977. The RGR of height for Q. mongolica ssp. crispula was 0.122 $yr^{-1}$. The growth curve for DBH of P. densiflora was approximated by the logistic equation: $$DBH(t) = 30 {[1+1.16exp(-0.13 t)]}^{-1}$$ where DBH (t) the DBH (cm) in year t and t is the number of years since 1977. The growth in height of P. densiflora and Q. mongolica ssp. crispula was described by following equations: $$H (t) = 20.2 {[1+0.407exp(-0.137 t)]}^{-1} (P. densiflora)$$ $$H (t) = 30 {[1+20.7exp(-0.122 t)}^{-1} (Q. mongolica ssp. crispula)$$ Where H (t) is the tree height (m) in year t and t is the number of years since 1977 in P. densiflora and 1998 in Q. mongolica ssp. crispula. With these equations we predicted that the height of Q. mongolica ssp. crispula increases from 2 m in 1999 to 20 m in 2029. Therefore, Q. mongolica ssp. crispula and P. densiflora will be approximately the same height in 2029. The years required for succession from a pine forest to an oak forest are expected 33 with the range between 23 and 44 years.

• Korean Journal of Environment and Ecology
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• v.11 no.4
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• pp.433-449
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• 1998

To study the plant community structure of Chayang-chon area from Jangsudae to Hangyeryung in Soraksan National Park, 62 plots(each size 100m$^2$) were set up and surveyed. Six communities(Pinus densiflora - Populus caximowiczii community, P. densiflora community, P. densiflora - Deciduous broad-leaved tree community, Quercus mongolica community, Q. mongolica - Carpinus cordata community, C. cordata - Deciduous broad- leaved tree community) were classified by DCA ordination techniques. Q. mongolica community, Q. mongolica - C. cordata and C. cordata - Deciduous broad-leaved tree community were distrivuted over altitude 755m, and the others were distributed below there. In the community over altitude 755m, the succession that Q. mongolica community changed to C. cordata community have proceeded partly and otherwise C. cordata community and Deciduous broad-leaved tree community have been competing with each other. In the community with distribytion range from 500m to 560, high, P. densiflora community would change deciduous broad-leaved tree community forward.

• Journal of Ecology and Environment
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• v.33 no.1
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• pp.67-77
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• 2010

Stand structure and spatial associations of the dominant tree species in Quercus mongolica stands were investigated to understand interspecific relationships and the persistent dominance of Q. mongolica. We examined the species composition, DBH (diameter at breast height) distribution, and spatial distribution of trees (${\geq}\;2.5\;cm$ DBH) in two permanent $100\;m\;{\times}\;100\;m$ plots in Q. mongolica-dominant stands on the western part of Mt. Jiri. Ripley's K-function was used to characterize the spatial patterns and associations of dominant tree species. Q. mongolica showed a continuous and reverse-J shaped DBH distribution with clumped spatial distribution in both study sites. Q. mongolica and Abies koreana exhibited a negative association implying potential interspecific competition. The positive spatial association between Q. mongolica and Alnus hirsuta var. sibirica and Fraxinus sieboldiana were affected by site characteristics: limited habitat conditions with a large proportion of rock surface. Our results suggest that interactions among species were complex and ranged from positive to negative. Differences in stand and site characteristics and regeneration mechanisms among the species play an important role in regulating their spatial distribution patterns, while competition between individuals also contributes to spatial patterning of these communities. The high density and the early developmental stage of spatial distribution and structural characteristics of Q. mongolica and the relatively low importance values of other species in the stands imply that Q. mongolica will remain dominant in the study sites in the near future.

• Genomics & Informatics
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• v.10 no.1
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• pp.9-15
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• 2012

Horizontal gene transfer (HGT) is the movement of genetic material between kingdoms and is considered to play a positive role in adaptation. $Cryptosporidium$ $parvum$ is a parasitic protozoan that causes an infectious disease. Its genome sequencing reported 14 bacteria-like proteins in the nuclear genome. Among them, cgd2_1810, which has been annotated as CysQ, a sulfite synthesis pathway protein, is listed as one of the candidates of genes horizontally transferred from bacterial origin. In this report, we examined this issue using phylogenetic analysis. Our BLAST search showed that $C.$ $parvum$ CysQ protein had the highest similarity with that of proteobacteria. Analysis with NCBI's Conserved Domain Tree showed phylogenetic incongruence, in that $C.$ $parvum$ CysQ protein was located within a branch of proteobacteria in the cd01638 domain, a bacterial member of the inositol monophosphatase family. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, the sulfate assimilation pathway, where CysQ plays an important role, is well conserved in most eukaryotes as well as prokaryotes. However, the Apicomplexa, including $C.$ $parvum$, largely lack orthologous genes of the pathway, suggesting its loss in those protozoan lineages. Therefore, we conclude that $C.$ $parvum$ regained cysQ from proteobacteria by HGT, although its functional role is elusive.