• Journal of Ecology and Environment
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• v.37 no.2
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• pp.53-60
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• 2014

The arctic tundra is an important ecosystem in terms of the organic carbon cycle and climate change, and therefore, detailed analysis of vegetation distribution patterns is required to determine their association. We used grid-sampling method and applied geostatistics to analyze spatial variability and patterns of vegetation within a two-dimensional space, and calculated the Moran's I statistics and semivariance to assess the spatial autocorrelation of vegetation. Spatially autocorrelated vegetation consisted of moss, Eriophorum vaginatum, Betula nana, and Rubus chamaemorus. Interpolation maps and cross-correlograms revealed spatial specificity of Carex aquatilis and a strong negative spatial correlation between E. vaginatum and C. aquatilis. These results suggest differences between the species in water requirements for survival in the arctic tundra. Geostatistical methods could offer valuable information for identifying the vegetation spatial distribution.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.3
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• pp.171-176
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• 2016

The distribution shapes of air and water temperatures are basic and essential information, which determine the frequency patterns of their occurrence. It is also very useful to understand the changes in long-term air and water temperatures with respect to climate change. The typical distribution shapes of air and water temperatures cannot be well fitted using widely used/accepted normal distributions because their shapes show multimodal distributions. In this study, Gaussian mixture distributions and kernel distributions are suggested as the more suitable models to fit their distribution shapes. Based on the results, the tail shape exhibits different patterns. The tail is long in higher temperature regions of water temperature distribution and in lower temperature regions of air temperature distribution. These types of shape comparisons can be useful to identify the patterns of long-term air and water temperature changes and the relationship between air and water temperatures. It is nearly impossible to identify change patterns using only mean-temperatures and normal distributions.

• Journal of Cadastre & Land InformatiX
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• v.50 no.2
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• pp.203-219
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• 2020

The primary purpose of this study is to identify spatial distribution patterns of co-authoring activities in Korean cadastral science. The analysis showed that a small number of researchers played an essential role in the Korean cadastral co-authorship network. In particular, some authors not only had a significant influence on other nodes in the network but also served as intermediaries between researchers. Moreover, the distance between researchers influenced co-authorship decisions to a limited extent. This study differs considerably from previous studies in that it used spatial analysis techniques to identify spatial distribution patterns of co-authoring activities. However, this research is limited in that it applied only 2019 data to determine the spatial distribution pattern of co-authoring activities. We can overcome this limitation if we analyze the spatial distribution patterns of co-authoring activities using multi-year data in future studies.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.49 no.1
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• pp.19-23
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• 2000

Partial discharges(PD)in air insulated electric power apparatus often lead to deterioration of solid insulation by electron bombardments and electrochemical reaction. The PD caused to reduce the life time of power apparatus and to increase power losses. Thus understanding and classification of PD patterns in air are very important to discern sources of PD. In this paper, PD in air by using statistical methods was investigated. We classified air discharges, corona, surface discharges and cavity discharges by Kohonen network. For classification of PD patterns, we used statistical operators and parameters such as skewness$(S^+,\; S^-),\; kurtosis(K^+, K^-),\; mean phase(AP^+, AP^-)$, cross-correlation factor(CC) and asymmetry derived from the mean pulse-height phase distribution$(H_{avg}(\phi))$, the max pulse-height phase distribution $(H_{qmax}(\phi))$, the pulse count phase distribution $(H_n(\phi))$ and the pulse height vs. Repetition rate $(H_q(n))$.

• 한국연소학회:학술대회논문집
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• 2006.10a
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• pp.137-144
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• 2006

Oil-fired power plants usually use several burners and the combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner evenly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and uneven supplies of combustion air to each burner are induced by these unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in the windbox and measured the velocities at the exit of burners in the real windbox to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric and this increases the pollutant products like CO.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.85-92
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• 2005

Oil-fired power plants usually use several burners and the combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner evenly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and uneven supplies of combustion air to each burner are induced by these unbalanced flow distribution in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in the windbox and measured the velocities at the exit of burners in the real windbox to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric and this increases the pollutant products like CO.

• Journal of the Korean Society of Combustion
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• v.11 no.1
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• pp.1-10
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• 2006

Oil-fired power plant usually uses several burners and combustion air is supplied to each burner through the complicated duct which is called windbox. A windbox should be designed to supply combustion air to each burner uniformly but, due to the complicated duct shape, flow distribution in the windbox is unbalanced and non-uniform supplies of combustion air are induced by these unbalanced flows in the windbox. These flow patterns tend to make flame unstable, increase the formation of pollutants and lower the overall combustion efficiency. To prevent these disadvantages, flow patterns in the windbox should be investigated for the uniform flow distribution. In this study, computational simulation method was used to investigate the flow distribution in a windbox and measured the velocities at the exit of burners in a real windbox and model tests to compare with CFD results. The results show two significant flow patterns. One is that the flow rates of each burner are different from each other and this means that all burners operate in different conditions of air to fuel ratio. The other is that the flow distribution at the exit of each burner is not axi-symmetric although the burner shape is axi-symmetric. Additionally some modifications of windbox shape and installation of baffles were proposed to make the uniform flow in the windox.

• ALGAE
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• v.36 no.1
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• pp.13-24
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• 2021

The present-day genetic structure of macroalgal species reflects both geographical history and oceanic circulation patterns as well as anthropogenic introduction across native ranges. To precisely understand the genetic diversity and how the factors shape the current population structure of Gloiopeltis furcata sensu lato, we determined the mitochondrial 5' end of cytochrome c oxidase subunit I (COI-5P) sequences for 677 individuals sampled from 67 sites spanning almost the entire distribution range in Korea and Japan. Results from the phylogenetic analysis and haplotype distribution revealed eleven distinct lineages within G. furcata s.l. along the Korea-Japan coastal areas and displayed divergent phylogeographic patterns among lineages. Despite the closely related lineages distributed in same habitats as high rocky intertidal zone, they display different phylogeographic patterns among lineages. The populations from the south of Korea-Japan harbored the highest genetic diversity and unique endemism in comparison with other populations in the distribution range. This could be the evidence of southern refugia for G. furcata s.l. in the Northwest (NW) Pacific and the recent migration from native to introduced region. The reason is that an exceptional distribution pattern was found high genetic diversity in Hakodate of Japan where is the northern location in the NW Pacific. Our results imply the contemporary influence on the distribution due to current circulation pattern and anthropogenic effects. These phylogeographic findings provide the important insight into cryptic species diversity and the detailed distribution pattern of Gloiopeltis in the NW Pacific.

• ALGAE
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• v.27 no.4
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• pp.269-281
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• 2012

Marado is a small rocky island located off the south coast of Jeju Island and acts as the first gateway of the Kuroshio Current to Korean coastal ecosystems. This island is one of the most unpolluted and well preserved sea areas around the Jeju coast. We extensively observed macroalgal assemblages of species and functional forms in the intertidal and subtidal zones through four seasons on Marado, Jeju Island, Korea to demonstrate the seasonality of vertical distribution patterns and biomass. A total of 144 species (14 Chlorophyta, 40 Phaeophyta, and 90 Rhodophyta) were identified in quadrats and were analyzed seasonally and vertically to define the variation patterns. The annual mean biomass of macroalgae was $2,932.3g\;wet\;wt\;m^{-2}$ and the highest value was recorded in spring and the lowest was in winter. The annual dominant species by biomass was Ecklonia cava followed by Sargassum fusiforme, S. macrocarpum, Amphiroa galapagensis, Chondria crassicaulis, and S. thunbergii. Obvious biomass zonation patterns of macroalgal species were detected in relation to tidal height and depth. Macroalgal biomass, diversity index (H'), and community dynamics were the highest in the shallow subtidal zone. Species number was higher in the subtidal than in the intertidal zone and similar throughout the entire subtidal zone. Our results provide revealing insights into the distribution patterns of macroalgal assemblages in an unpolluted sea area around Jeju Island.

• Physical Therapy Korea
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• v.3 no.2
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• pp.55-76
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• 1996

The objective of this study was to identify the immediate effects of the short leg brace on the weight bearing distribution and gait patterns of hemiplegic patients. The subjects of this study were 18 hemiplegic patients who had been hospitalized or visited out-patient department of Rehabilitation Hospital, Yonsei University College of Medicine, from January 5, 1996 through March 23, 1996. PLS(Posterior Leaf Spring) on and off changes in gait patterns were measured using ink foot print as well as by recording weight bearing distribution using a limb load monitor. The data were analyzed by the correlation and paired t-test. The findings were as follows: 1. Eighteen subjects were more weighted on the affected leg when PLS was put off(42.74%) than on(40.08%). 2. The defference in gait patterns between PLS on and off was statistically significant, with an increase in step length by 1.7cm on the involved side; a decrease in foot angle by 4.41 degree on the involved side; and a narrowing of base of support by 1.46cm when PLS were off. In conclusion, this study showed that PLS did not affect the weight bearing distribution and gait patterns of hemiplegic patients. Since, the evaluation method used in this study has limitations in regard to temporal distance gait values. Further studies are required to numerous experiments for subject and extensive study.