• Korean Journal of Environment and Ecology
• /
• v.20 no.2
• /
• pp.122-129
• /
• 2006

To investigate the vegetation structure of mountain region from Wolgagsan to Dogabjae, 14 plots($2000m^2$) set up with random sampling method were surveyed. Two groups of Quercus variabilis-Pinus densiflora community, Quercus mongolica-Quercus acutissima community were classified by cluster analysis. Quercus variabilis, Pinus densiflora, Quercus mongolica, Quercus acutissima, Quercus dentata and Quercus serrata were found as a major woody plant species in Weolchulsan National Park region. In this area, Quercus variabilis and Pinus densiflora were dominated partially. In the future, the importance percentage of Pinus densiflora might be decreased, but those of Quercus variabilis, Quercus mongolica, Quercus acutissima and Quercus dentata might be increased. High positive correlations was proved between Quercus variabilis and Pinus rigida; Styrax japonica and Quercus dentata, Quercus acutissima; Pinus rigida and Lindera erythrocarpa, Pinus densiflora; Lindera obtusiloba and Rhododendron mucronulatum; Albizzia julibrissin and Styrax obassia, and relatively high negative correlations was proved between Diospyros kaki and Quercus dentata; Platycarya strobilacea and Lindera erythrocarpa; Symplocos chinensis for. pilosa and Quercus acutissima; Styrax japonica and Styrax obassia; Pinus rigida and Lindera obtusiloba, Fraxinus sieboldiana, Rhododendron mucronulatum; Quercus mongolica and Albizzia julibrissin. Species diversity(H') of investigated groups was ranged $1.2430{\sim}1.2892$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.11a
• /
• pp.293-296
• /
• 2004

초고압 케이블의 절연물질로 널리 사용되고 있는 가교 폴리에틸렌의 전기적 특성은 라멜라 결정 조직의 밀도와 라멜라 조직의 성장방향과 밀접한 관련이 있는 것으로 알려지고 있다. 본 연구에서는 반도전 물질에 2종의 첨가제를 이용하여 처방한 3종의 반도전 컴파운드에 대하여 시편 제작 조건에 따른 미세 조직을 제어하여 폴리에틸렌의 미세 조직을 변화시킴으로써, 라멜라 조직이 전기적 특성에 미치는 영향을 분석하였다. 전기적 특성은 AC 절연파괴 전압을 측정하였으며, 미세 조직 변화를 조사하기 위하여 TEM 이미지 분석 통하여 라멜라 밀도를 통계적으로 정성 분석하여 상관관계를 규명하였다.

• Proceedings of the KIEE Conference
• /
• 2004.11a
• /
• pp.205-208
• /
• 2004

초고압 케이블의 절연물질로 널리 사용되고 있는 가교 폴리에틸렌의 전기적 특성은 라멜라결정 조직의 밀도와 라멜라 조직의 성장방향과 밀접한 관련이 있는 것으로 알려지고 있다. 본 연구에서는 반도전 물질에 2종의 첨가제를 이용하여 처방한 3종의 반도전 컴파운드에 대하여 시편 제작 조건에 따른 미세 조직을 제어하여 폴리에틸렌의 미세 조직을 변화시킴으로써, 라멜라 조직이 전기적 특성에 미치는 영향을 분석하였다. 전기적 특성은 AC 절연파괴 전압을 측정하였으며, 미세조직 변화를 조사하기 위하여 TEM 이미지 분석 통하여 라멜라 밀도를 통계적으로 정성 분석하여 상관관계를 규명하였다.

• Journal of the Korea Concrete Institute
• /
• v.13 no.6
• /
• pp.610-618
• /
• 2001

This paper investigates the relationships between dynamic elastic modulus and static elastic modulus or compressive strength according to curing temperature, aging, and cement type. Based on this investigation, the new model of the relationships we proposed. Impact echo method estimates the resonant frequency of specimens and uniaxial compression test measures the static elastic modulus and compressive strength. Type I and V cement concretes, which have the water-cement ratios of 0.40 and 0.50, are cured under the isothermal curing temperatures of 10, 23, and 50$\^{C}$ Cement type and aging have no large influence on the relationship between dynamic and static elastic modulus, but the ratio of dynamic and static elastic modulus comes close to 1 as temperature increases. Initial chord elastic modulus which is calculated at lower strain level of stress-strain curve, has the similar value to dynamic elastic modulus. The relationship between dynamic elastic modulus and compressive strength has the same tendency as the relationship between dynamic and static elastic modulus according to cement type, temperature and aging. The proposcd relationship equations between dynamic elastic modulus and static elastic modulus or compressive strength properly estimates the variation of relationships according to cement type md temperature.

• Journal of Environmental Impact Assessment
• /
• v.24 no.3
• /
• pp.233-243
• /
• 2015

The ecosystem fragmentation due to transportation infrastructure causes road-kill phenomenon. When making policy for reducing road-kill it is important to select target-species in order to enhance its efficiency. However, many corridors installed in Korea have been raised issues about their effectiveness due to lack of considerations such as target-species selection, site selection, and management, etc. In this study, we are to grasp relationship between road-kill area and habitat patches and suggest that spatial location of habitat patches should be considered as one of the important factors when making policy for reducing road-kill. Habitat patches were presumed from overlying suitability index that chosen by literature review and road-kill hotspot was determined by Getis-Ord $G_i^*$ analysis. Afterwards, we performed a correlation analysis between $G_i$ Z-score and the distance from habitat patches to the roads. As a result, there is a negative correlation between two variables, It affects the $G_i^*$ Z-score going up if the habitat patches and the roads become closer.

• Korean Journal of Ecology and Environment
• /
• v.48 no.2
• /
• pp.115-121
• /
• 2015

In order to assess the water quality of Kumho river using Diatom Assemblage Index to organic water pollution (DAIpo) and to campare from the previous water quality, 5 sites in Kumho river were selected and assessed total of 6 times, every April and September from April 2010 to September 2012. As a result, 116 taxa were found in 2 Order, 3 Suborder, 7 Families, 26 Genera, 103 species and 13 varieties. Saprophilous species of 10 dominant species including Achnanthes minutissima, were increased as going to downstream sites. Correlation coefficients (r) between epilithic diatom communities and physicochemical factors were from - 0.62 to 0.71. Correlation coefficients (r) between TN and diatom indices (DAIpo, TDI) were 0.57 and 0.65, respectively. Therefore, epilithic diatom communities were greatly influenced by TN. The Correlation between DAIpo and TDI measured to be high in correlation coefficient (r=0.62) from the result of correlation analysis. Mean of DAIpo values ranged between 37.24~74.98 and decreased as going to downstream sites. Saprobic level was estimated as ${\beta}$-oligosaprobic at st. 1, ${\alpha}$-oligosaprobic at st. 2 and ${\beta}$-mesosaprobic at st. 3. But st. 4 and 5 which were ${\alpha}$-mesosaprobic and polysaprobic in the previous results, were improved as ${\beta}$-mesosaprobic. The RPId, general assessment of the water quality using DAIpo, was 52.27, which means the water quality of Kumho river was middle level.

• The Journal of the Korea Contents Association
• /
• v.17 no.5
• /
• pp.234-242
• /
• 2017

This study selected 60 board games that have a high sales rate and awareness in the board game market, and analyzed 37 board games that were selected through the advice of experts. According to the analysis of general characteristics, there was the highest number of board games that more than 2 people could participate and people from ages 7 to 11 could use, and the most common play time was from 20 minutes to 30 minutes. Also, there was the largest number of board games produced in 2000s, and Germany was the most common producer of board games. Next, the content analysis showed that abstract strategy was the most common game genre, and cognitive domain was the most common in the development area. The analysis based on how to play the game showed that games that had to go through 4 stages were the most common. Card games were the most common form of game, group was the most common in organization form, and reaching goal was most common among result analysis method. According to the analysis of correlation by items, the number of people and work analysis had a statistical correlation, and the playing age, time, and genre had a correlation. The origin of the game and game genre were also correlated to each other, and game form, game genre, organization form, and result analysis had a statistical correlation as well. The purpose of this study is to analyze the board game in terms of structural characteristics and to provide a foundation for future research.

• Journal of Sericultural and Entomological Science
• /
• v.31 no.2
• /
• pp.102-112
• /
• 1989

Principal component analysis and cluster analysis were performed on the nine quantitative characters of the one hundred and forty eight silkworm genetic stocks. The six major quantitative characters such as cocoon yield, cocoon weight, cocoon shell weight, cocoon shell percentage, larval period of the 5th instar silkworm, and total larval period showed significantly positive correlation between them. The first three principal components extracted form the initial nine variables by principal component analysis accounted for about eighty percent of original information. The first and second principal components were characterized as factors related to silk productivity, and cocoon productivity, respectively. On the basis of multivariate analysis using city block distance determined from the first three principal components to measure the phenotypic diversity, the one hundred and forty eight silkworm genetic stocks could be clustered into seven varietal groups, and the phenotypic diversity between the varietal groups was partly related to their geographical origins. Among 7 varietal group, group II and IV revealed higher silk and cocoon productivity.

• Korean Journal of Environment and Ecology
• /
• v.31 no.3
• /
• pp.318-328
• /
• 2017

In order to provide basic data for the ecological management of forest vegetation in Southern Naeyeon Mountains, A total of 149 sample plots were selected and vegetation survey was carried out by the phytosociological method of the ZM school to classify vegetation types and to grasp ecological characteristics. The forest vegetation was divided into 10 types in terms of species composition, and had a unit hierarchy of 2 community groups, 4 communities, 6 sub-communities and 6 variants. A total of 19 types of physiognomic vegetation were identified based on uppermost dominant species, of which 18 were natural vegetation and 1 was artificial vegetation. As a result of the analysis of the importance values of constituent species, Quercus mongolica, a potentially natural vegetation element, was found to be relatively more important in most stands than other species, and excluding the artificial interference, most of the areas except for some sites would be changed to Q. mongolica forest. In order to understand the spatial distribution of forest vegetation, 1/5,000 large-scale physiognomic vegetation map was created by the uppermost dominant species. As a result, natural vegetation accounted for 98.2%, the number of vegetation patches was 733 and the average area per patch 3.93ha.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.39 no.4
• /
• pp.397-404
• /
• 1994

This experiment was conducted to determine best harvesting time and observe paeoniflorin and some chemical component concentrations of 4-year-old paeonia radix in Euisung and Milyang varieties. Concentrations of paeoniflorin and some chemical components were investigated at 8 periods from Feb. to Oct. Yield of paeonia radix was investigated in Aug. 19, Sep. 18 and Oct. 17. Paeoniflorin and some chemical components were changed seriously at May as flowering time and stabilized after June. The lowest dry matter ratio was 23% and the maximum shrinkage ratio was 47% in May during all the growing stages. Especially, the difference of paeoniflorin concentrations between Euisung and Milyang was about 2%, and paeoniflorin concentrations in Milyang were higher than in Euisung variety during all the stages. Serious infection of disease in October, stem length, stem number per stock and healthful stem ratio in October were more reduced than in August. Yield of paeonia radix was not different from August to September, but that of October harvest was obviously reduced by root-decay-disease. Reasonable harvesting time in 4-year-old paeonia radix was late August to mid-September. When infected shoot rate by disease were severely high, early harvest was more stable in the yield and quality aspects.