• Title/Summary/Keyword: 구조VAR

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Changes in Real Exchange Rate and Business Fluctuations: A Comparative Study of Korea and Japan (실질환율변동의 경기변동효과: 한국과 일본의 비교연구)

  • Kwak, Tae Woon
    • International Area Studies Review
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    • v.13 no.3
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    • pp.309-330
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    • 2009
  • This paper analyzes comparatively the effects of changes in real effective exchange rates on the business fluctuations of the cases of Korea and Japan employing structural vector auto-regression(S-VAR) model which uses quarterly data for the five variables of real effective exchange rates, GDP gap, real interest rates, oil prices, inflation rates for the period of 1980-2006. The paper employes impulse-response analysis and variance decompositions. The paper finds that real exchange rate depreciations are contractionay for the case of Korea while they are expansionary for the case of Japan. These results are consistent with the prevailing empirical results that real exchange rate depreciations are contractionary for developing countries while expansionary for advanced countries.

Taxonomic study on infraspecific taxa of Lespedeza maximowiczii and hybrids with related species (조록싸리 종내분류군과 잡종의 분류학적 연구)

  • JIN, Dong-Pil;PARK, Jong-Won;CHOI, Byoung-Hee
    • Korean Journal of Plant Taxonomy
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    • v.49 no.4
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    • pp.300-318
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    • 2019
  • Many infraspecific taxa within Lespedeza maximowiczii and hybrids with related species have been described, but taxonomic verification remains controversial. We examined the morphological traits of hybrids (L. chiisanensis and L. patentibicolor) and infraspecific taxa (var. tomentella, elongata, and tricolor) and analyzed their genetic structures using microsatellite loci. Flower and leaflet shapes in var. tomentella and elongata were within the range of variation of those in var. maximowiczii, and individuals in the two former varieties were grouped into var. maximowiczii. Lespedeza maximowiczii var. tricolor was similar to L. buergeri in terms of the structure and flower color, whereas the leaflet and bracteole shapes of var. tricolor were similar to those of var. maximowiczii. Based on the genetic structure (K = 3), var. tricolor had a mixed lineage with L. maximowiczii and L. buergeri. In addition, these formed a distinct lineage at K = 5. For two hybrids, the flower and leaflet structure in L. chiisanensis did not differ from those in L. maximowiczii, whereas the flowers of L. patentibicolor were within the range of variation of L. bicolor. In addition, L. chiisanensis and L. patentibicolor were assigned to L. maximowiczii and L. bicolor, respectively, based on the genetic structure. We treated var. tomentella and elongata as a forma, f. friebeana, because L. friebeana preceded var. tomentella, whereas var. tricolor was treated as a distinct species, L. tricolor. Lespedeza chiisanensis was recognized as a synonym of L. maximowiczii. Lespedeza patentibicolor was considered to be L. bicolor.

Comparison of Foliar Ultrastructure of 3 Dubautia species (Dubautia속(屬) 3종(種) 식물(植物)의 엽육조직(葉肉組織) 미세구조(微細構造) 비교연구(比較硏究))

  • Kim, In-Sun
    • Applied Microscopy
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    • v.24 no.4
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    • pp.13-31
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    • 1994
  • The fine structure of palisade chloroplasts has been studied in the mature leaves of 3 Dubautia species (D. scabra var. leiophylla, D. knudsenii and D. scabra var. leiophylla${\times}$D. knudsenii) to explore variation at the ultrastructural level, since the parental species exhibit quite different morphological and anatomical features. Types of thylakoidal membrane systems, occurrence and distribution of phytoferritin-like structures, lipid droplets, starch grains, mitochondria and microbodies were examined. Four different types of thylakoidal membranes were found in D. scabra var. leiophylla, 2 rather uniform types in D. knudsenii and 3 intermediate types in their hybrid. D. scabra var. leiophylla and the hybrid were marked by statistically significant differences in mean numbers of thylakoids per granum, while no significant difference was found between D. knudsenii and the hybrid. Phytoferritin-like structures which were about $100-120{\AA}$ in diameter as a whole particle each were found in all 3 species. The amount and distribution of particles varied by species. Lipid droplets, plastoglobuli, and starch grains occurred in all 3 species, but the frequency of starch grains also varied with the species. More frequent and larger starch grains were observed in D. knudsenii than in the other two species. Microbodies, or peroxisome, were observed throughout all species. They occurred, either with or without crystalline inclusions, around the chloroplasts.

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Taxonomic position and genetic differentiation of Korean Astragalus mongholicus Bunge (한국산 황기의 분류학적 위치 및 유전적 분화)

  • Choi, In-Su;Kim, So-Young;Choi, Byoung-Hee
    • Korean Journal of Plant Taxonomy
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    • v.43 no.1
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    • pp.12-21
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    • 2013
  • To clarify the taxonomic position for Astragalus nakaianus and provide correct scientific name for A. mongholicus cultivar in South Korea, we examined external morphological characters and sequence variations from ITS and five cp non-coding DNA regions. Genetic structure was also analyzed for 61 individuals from three populations using nine microsatellite loci. We found no significant difference between the South Korean cultivar and A. mongholicus var. dahuricus when morphology and ITS sequences were considered. Morphologically, A. nakaianus specimens varied somewhat from A. mongholicus var. mongholicus and var. dahuricus in habit, plant height, and lengths of leaf axis and leaflet. Although sequence data from ITS and cp noncoding DNA regions could not distinguished A. nakaianus from A. mongholicus, microsatellite analysis revealed strong structuring between the cultivar and A. nakaianus. Therefore, we conclude that the South Korean A. mongholicus cultivar should be treated as A. mongholicus var. dahuricus and that A. nakaianus should be merged into A. mongholicus as a variety, i.e., A. mongholicus var. nakaianus.

A Study on the Vessel Structure of Fagaceae Species in Korea (II) -Micromorphology of Vessel Wall Sculpture- (한국산(韓國産) 참나무과(科) 수종(樹種) 도관구조(道管構造)에 관(關)한 연구(硏究)(II) -도관벽(導管壁)의 수식구조(修飾構造)-)

  • Lee, Sung Jae;Lee, Wan Yang
    • Journal of Forest and Environmental Science
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    • v.8 no.1
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    • pp.51-66
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    • 1992
  • This study was carried out to investigate the micromorphology of vessel wall sculpture such as shape of perforation plate, perforation rim, steepness of perforation plate, occurrence of vestured pit, warty layer and ray-vessel pitting on 13 species of Fagaceae in Korea. The results were summarized as follows ; 1. In the species examined, all sample species except Fagus crenata var. multinervis have simple perforation plate. But Fagus crenata var. multinervis has simple and scalariform perforation plate (it was called to combination perforation plate) in a tree stem. 2. The shapes of perforation rim could be classified into five types; Type A without tail, Type B with small tail on both sides, Type C with long tail on both sides, Type D with tail only one side and Type E with the very short interval between perforations. Among five types, Type Band C have higer frequency of distribution than the others. 3. The steepness of perforation plate measured was about 20 degree on pore zone and 43 degree on outside parts of pore zone. 4. Species with vestured pit were Q. aliena, Q, dentata, Q. variabilis, Fagus crenata var. multinervis, Castanopsis cuspidata var sieboldii, Q. acuta, Q. stenophylla, and Q. glauca. But the extent of vesturing was very slight and vestured pits were observed mainly in ray-vessel pit of some vessel elements. 5. Species with warty layer on the inner surface wall of all vessel elements were Q. acuta, Q. stenophylla, Q. glauca, Fagus crenata var. multinervis and species with warty layer of some vessel elements were Q. aliena, Q, dentata, Q. variabilis, Castanopsis cuspidata var. sieboldii. 6. Species with palisade ray-vessel pit were Q. acuta, Q. stenophylla, Q. glauca, Castanea crenata, Castanea bungeana, Q. aliena, Q. serrata, Q. mongolica, and species with scalariform ray-vessel pit was Fagus crenata var. multinervis and species with oval ray-vessel pit were Q, dentata, Castanopsis cuspidata var sieboldii.

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Vegetation Structure of the Songinbong Virgin Forest(Natural Monument) in Ullungdo, Korea (울릉도 성인봉 원시림의 산림군집구조)

  • 한봉호;김동완;조현서
    • Korean Journal of Environment and Ecology
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    • v.12 no.2
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    • pp.138-146
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    • 1998
  • Ten plots were established to study the vegetation structure of the Songinbong virgin forest in Ullungdo. It was classified into three communities Fagus crenata var. multinervis commnunity, Acer okamotoanum-Fagus crenata var. multinervis community, and Acer okamotoanum community. Shannon's diversity indicies of this area were not high(0.5150~0.8437), due to the geographical and vegetational characteristics. Considering the community structure(importance value, distribution of DBH class, and so on), the vegetation of the Songinbong virgin forest are thought to be stable continuously. With the analysis of plant growth type, it was presumed that Acer okamotoanum have increased after artificial disturbances in this area where Fagus crenata var. multinervis had been dominanat.

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Spatial Genetic Structure and Genetic Diversity of a Rare Endemic Juniperus chinensis var. sargentii in Mt. Halla, Korea (희귀식물인 눈향나무(Juniperus chinensis var. sargentii)의 공간분포에 따른 유전구조 및 유전적 다양성)

  • Choi, Hyung-Soon;Hong, Kyung-Nak;Chung, Jae-Min;Kim, Won-Woo
    • The Korean Journal of Ecology
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    • v.27 no.5
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    • pp.257-261
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    • 2004
  • Juniperus chinensis var. sargentii Henry is a short and creeping evergreen shrub which reaches about 50㎝ in height and occurs in the northeast Asia and in high mountains over the South Korea. Its distribution is restricted, and the number of individuals are gradually decreasing. This study was conducted to estimate spatial pattern, genetic diversity and spatial genetic structure of J. chinensis var. sargentii. A total of 131 clumps were studied in the study area (40m × 60m). The spatial pattern of this population was random (Aggregation index R=1.031). In spite of the small number and the limited distribution, the level of genetic diversity (Shannon's index 1=0.463) was relatively high as compared with those of other plant species with similar ecological characteristics. ISSR genotypes of all individuals were investigated to find the genetic relationship of clumps and genets. Fifteen clumps were composed to be clones, and a total of 116 unique genotypes were composed by separate genets. Spatial autocorrelation analysis using Tanimoto distance showed that the genetic patch was established within 8m. The effect of clonal reproduction on genetic structure was almost nothing.

The Structure of Forest Community and Vegetation Deteriorations on Subalpine Zone in Mt. Halla (한라산 아고산지대 식물군집구조 및 식생훼손)

  • Lee, Kyong-Jae;Cho, Woo;Cho, Hyun-Seo
    • Korean Journal of Environment and Ecology
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    • v.6 no.1
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    • pp.44-54
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    • 1992
  • A survey of subalpine zone (altitude is 1, 440-1, 700m) in Mt. Halla, was conducted using 37 sampling plots of l00$m^2$ size. The classification by TWINSPAN and RA. DCA ordination were applied to the study area in order to classify them based on woody plants and environmental variables. And to investigate vegetation deterioration by livestock's and user's impact on subalpine zone, seventeen plots were set up. By TWINSPAN techniques, the plant community were divided into five groups by the altitude. The dividing groups are Abies koreana-Taxus cuspidata community, Rhododendron yedoense var. poukhanense-Rh. mucronulatum var. ciliatum-Sasa quelpaertensis community, Ilex crenata- Elaeagnus umbellata-S. quelpaertensis community, Rh. yedoense var. poukhallense-Juniperus chinensis var. sargentii-Rh. mucronulatum var. ciliatum community and Empetrum nigrum var. japonicum-J. chinensis var. sargentii community. The species divirsity of plant community were decreased severely by livestock's and user's impact.

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Basidiospore Development and Fine Structure in Rhodophyllus muraii var. albus (흰꼭지외대버섯의 담자포자의 발생과 미세구조)

  • Cho, Duck-Hyun
    • Korean Journal of Plant Resources
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    • v.6 no.2
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    • pp.165-170
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    • 1993
  • Apexes of basidia in Rhodophyllus muraii var. albus are divided into four sections or depressed in the center. A spore is formed by inflation of the apex of the sterigma. The apex of the sterigma is swollen and changed from a papilla through a peinsform and a club into a globeform. Six spots of globose spore are regularly or irregularly depressed with hilum axes. Finally the spores come cuboid.

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A Study on the Comovements and Structural Changes of Global Business Cycles using MS-VAR models (MS-VAR 모형을 이용한 글로벌 경기변동의 동조화 및 구조적 변화에 대한 연구)

  • Lee, Kyung-Hee;Kim, Kyung-Soo
    • Management & Information Systems Review
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    • v.35 no.3
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    • pp.1-22
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    • 2016
  • We analyzed the international comovements and structural changes in the quarterly real GDP by the Markov-switching vector autoregressive model (MS-VAR) from 1971(1) to 2016(1). The main results of this study were as follows. First, the business cycle phenomenon that occurs in the models or individual time series in real GDP has been grasped through the MS-VAR models. Unlike previous studies, this study showed the significant comovements, asymmetry and structural changes in the MS-VAR model using a real GDP across countries. Second, even if there was a partial difference, there were remarkable structural changes in the economy contraction regime(recession), such as 1988(2) ending the global oil shock crisis and 2007(3) starting the global financial crisis by the MS-VAR model. Third, large-scale structural changes were generated in the economic expansion and/or contraction regime simultaneously among countries. We found that the second world oil shocks that occurred after the first global oil shocks of 1973 and 1974 were the main reasons that caused the large-scale comovements of the international real GDP among countries. In addition, the spillover between Korea and 5 countries has been weak during the Asian currency crisis from 1997 to 1999, but there was strong transmission between Korea and 5 countries at the end of 2007 including the period of the global financial crisis. Fourth, it showed characteristics that simultaneous correlation appeared to be high due to the country-specific shocks generated for each country with the regime switching using real GDP since 1973. Thus, we confirmed that conclusions were consistent with a number of theoretical and empirical evidence available, and the macro-economic changes were mainly caused by the global shocks for the past 30 years. This study found that the global business cycles were due to large-scale asymmetric shocks in addition to the general changes, and then showed the main international comovements and/or structural changes through country-specific shocks.

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