• Communications of Mathematical Education
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• v.22 no.4
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• pp.533-543
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• 2008

Recently, many advanced countries have used original ICT tools in their educational courses. But Korea didn't have any effective origin ICT tools in our mathematical education, compared with other countries which have developed various tools, for examples, Web-Mathematica and HP Calculator. Although we have the advanced IT environment, the educational environments in mathematics using ICT seems to be not promising. In this paper, we suggest a new mathematics education tools in ICT and the internet environments in Korea, and a teaching and studyingmodel for the teachers, students and classrooms. It is based on the Sage-Math and RPG. Sage-Math which is the software based on the web and RPG(Random Problem Generator) will give a good answer for the future of Korean mathematics ICT education.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.38 no.2
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• pp.77-94
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• 2020

Gugok poems were an important material for studying the Gugok landscape garden(九曲園林). the landscape feature(景物)that emerges from poetry is an important material that expresses the sense of placefulness and garden consciousness(園林意識). However, many studies are passive about plant materials that can explore the perception of nature or the aesthetic embodiment process. Therefore, this study seeks to discover various symbolic meanings and reveal the context of plants that have appeared in Gugok poems in order to expand the research material of the Gugok culture. To carry out the purpose of the study, I collected a total of 25 related poems from 18 Gugoks and found a total of 20 species of trees. I used 'R-program' to derive the meaning of trees and examined the meaning of trees by intertextuality. According to the study, the 20 species of trees contained symbolic meanings of world of Taoist hermit, pursuit of study, constancy, true pleasure, dignity, honest poverty, reign of peace, nostalgia. Many species focused on the symbolism of the 'world of Taoist hermit' and then on the 'dignity' was the most frequent. A number of species, except for the peach, zelkova and oak, had multiple meanings. Among them, pine trees and lotus had a wide range of symbolic meanings and different meanings depending on the characteristics of the surrounding landscape. While the Gugok culture generally targets natural scenery, Yongsan, Toegye, Deoksan, and Jusan showed the characteristics of strengthening or reproducing symbolic meanings through artificial plating and gardening. In order to overcome the limitations of the peach tree, which symbolizes 'Mureungdowon(武陵桃園)', Gugok poems used maple trees and reeds as alternative species. In accordance with the above context, the trees appearing in the Gugok poems expressed their symbolic meaning differently according to the landscape features, acts and purposes of the Gugoks, rather than sticking to the traditional meaning.

• Korean Journal of Environment and Ecology
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• v.33 no.5
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• pp.565-577
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• 2019

The purpose of this study was to understand the factors influencing the decline and the patterns of changes in Abies nephrolepis populations on Mt. Seorak. We installed permanent quadrats in the areas of the Gwittagicheongbong (peak), Gwanmoneungseon (ridge), and the Seorak Falls and have monitored the community structure, population dynamics, radial growth, and vitality in the quadrats since 2009. Excluding the Seorak Falls, the three research sites showed a three-layer structure in which the low-tree layer forms the canopy. Major tree species were Khingan fir, Korean arborvitae, Mongolian oak, Erman's birch, and Korean maple. The significance of Khingan fir in Seorak Falls decreased from 45.3% in 2009 to 36.8% in 2018. The number of shoots ($DBH{\geq}5cm$) was highest at 1,800 individuals/ha and 1,700 individuals/ha at the Gwittagicheongbong 2 and the Gwanmoneungseon, respectively. The mortality rates over the past 10 years were very high, at 38.3% and 35.3%, respectively, in the Gwittagicheongbong 1 and Seorak Falls. The most stable inverse J-shaped distribution in the Gwittagicheongbong 1 area was shown in the size-frequency distribution of the Khingan fir populations. The average annual ring growth of the Khingan fir was 0.96 ~ 1.73 mm/year, and the ring growth tended to decrease in the areas of Gwittagicheongbong 1, Gwanmoneungseon, and Seorak Falls, where the vitality was low. If the monitoring process continues, it will be possible to obtain basic data for the conservation and management of subalpine vegetation.

• Ecology and Resilient Infrastructure
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• v.7 no.4
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• pp.284-293
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• 2020

We present a quantitative survey of the carbon storage and absorption capacity of tree species in the vegetation conservation and ecological restoration areas of Bulamsan urban nature park in Nowon-gu, Seoul. The density of the sawtooth oak (Quercus acutissima) community in the ecological conservation area is approximately 30 individuals/225 ㎡, while a further 20 species, such as Japanese snowbell (Styrax obassia), galcham oak (Quercus aliena), Asian Sweetleaf (Symplocos chinensis f. pilosa), East Asian ash (Fraxinus rhynchophylla), and Korean rhododendron (Rhododendron mucronulatum) are sparsely distributed. In contrast, the ecological restoration sites typically comprised Mongolian oak (Quercus mongolica), jolcham oak (Quercus serrata), and East Asian ash (Fraxinus rhynchophylla) plantations, with planting densities of 8.3, 7.7, and 14.3 individuals/25 ㎡ , respectively. Approximately 10 species, including Amur maple (Acer tataricum subsp. ginnala), Korean mountain ash (Sorbus alnifolia), Japanese spice bush (Lindera obtusiloba), and Korean rhododendron (Rhododendron mucronulatum) were identified in the ecologically restored area. The total amounts of carbon stored by the trees in the vegetation conservation and ecological restoration sites are 250.77 and 19.3 t C ha-1, respectively, and the total annual carbon uptakes are 10.28 and 2.33 t C ha-1 yr-1, respectively. The survey results are expected to provide important basic data for monitoring the carbon absorption capacity and carbon balance of green areas in the city.

• Journal of Korean Society of Forest Science
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• v.100 no.4
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• pp.715-721
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• 2011

This study was conducted to estimate aboveground biomass and nitrogen storage potential of tree species-eight clones of a poplar and hybrids, one clone of Salix alba L., dawn redwood (Metasequoia glyptostroboides Hu and W.C. Cheng), yellow poplar (Liriodendron tulipifera L.), Okamoto maple (Acer okamotoanum Nakai), and pin oak (Quercus palustris $M{\ddot{u}}nchh.$)- after treating with liquid pig manure. Stems showed the highest percentage of aboveground biomass, and followed by branches and leaves. Nitrogen content in aboveground biomass components was the highest in leaves, and followed by branches and stems. Average aboveground biomass production was higher in the clones and species treated with manure than those of not treated, 30 ton/ha and 16 ton/ha, respectively. In the manure-treated site, clone 'Dorskamp' of Populus deltoides${\times}$Populus nigra showed the highest aboveground biomass (48.3 ton/ha). Average nitrogen storage potential was superior in the clones and species treated with manure than those of not treated, 159 kg/ha and 90 kg/ha, respectively. Clone 'Dorskamp' also showed the greatest nitrogen storage potential (286.5 kg/ha) among tested tree species. Therefore, 'Dorskamp' is the most suitable clone for treating liquid pig manure, but additional studies are needed to determine any damages or tolerance from the treatment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.8
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• pp.573-581
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• 2022

This paper deals with the development of CanSat system, which ejects two maple seed-type autorotating science payloads and collects weather information. The CanSat consists of two autorotating science payloads and a container. The container is equipped with devices for launching science payloads and communication with the ground station, and launches science payloads one by one at different designated altitudes. The science payload consists of a space for loading and a large wing, and rotates to generate lift for slowing down the fall speed. Specifically, after being ejected, it descends at a speed of 20 m/s or less, measures the rotation rate, atmospheric pressure, and temperature, and transmits the measured value to the container at a rate of once per second. The communication system is a master-slave structure, and the science payload transmits all data to the master container, which aggregates both the received data and its own data, and transmits it to the ground station. All telemetry can be checked in real time using the ground station software developed in-house. A simulation was performed in the simulation environment, and the performance of the CanSat system that satisfies the mission requirements was confirmed.

• Korean Journal of Plant Resources
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• v.37 no.2
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• pp.137-148
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• 2024

The purpose of this study is to investigate the weather, soil characteristics, and location environment of Pimpinella brachycarpa natural habitats in order to gather the essential information for the conservation of these habitats. P. brachycarpa are distributed throughout Korea and are mainly found to grow in shady and humid areas between 500 and 1,200 m above sea level. The average annual temperature in Mt. Duta was 13.1℃, and the average annual precipitation in Mt. Jungwon was 1,509 mm, which was higher than in other regions. The pH ranged from 4.42 to 4.97, indicating slight acidity. The total N content ranged from 0.18% to 0.68%, and the available P ranged from 13.43 to 531.56 mg/kg, demonstrating notable regional variations. The species diversity index (H') was highest at Mt. Ilwol, measuring 1.713. The evenness (J') ranged from 0.983 to 0.993, and the dominance (D') ranged from 0.007 to 0.017. The similarity index was very low, averaging 24.86%, and it was divided into communities of Wilson's elm (Ulmus davidiana var. japonica) and communities of Korean maple (Acer pseudo-siebodianum).

• Journal of Korean Society of Forest Science
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• v.84 no.4
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• pp.415-423
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• 1995

This study was conducted to analyze the chemical composition, nutritional contents, and saponin in the xylem sap of Acer mono Max. From Feb 25 to Mar 4, 1994, spring sap was collected by making holes with 1.7cm diameter on the trunk of trees in Mt. Baekwoon and Mt. Jiri. Sugars were quantified by HPIC, amino acids by amino acid analyzer, saponins by TLC, HPLC, and $^1H$ & $^{13}C$ NMR. Major component of the sap was sucrose at a concentration range of 0.68 to 2.01%. Following minor components were found: glucose at 0.03-0.11%, and fructose at 0.01-0.03% as sugars, lipid at 0.03%, threonine at 0.152%, lysine at 0.038%, arginine at 0.068% as amino acids, ash at 0.1%, Ca at 175ppm, Fe at 2ppm, P at 19ppm, K at 16ppm, Na at 31ppm as minerals, vitamin $B_1$ at 0.6ppm, vit. $B_2$ at 0.1ppm, and vit. C at 19ppm. A trace of phenolic compounds was found by TLC, while saponin commonly reported in high-quality ginseng roots was not found in maple sap. It is concluded that sap of Acer mono contains a good variety of natural compounds such as sugars, amino acids, Ca, Fe, and vitamins to serve as an excellent source of very natural and health-promoting drink.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.2
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• pp.94-108
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• 2010

The purpose of this study is to provide data for the restoration of 'Yongyun(龍淵)' and 'Hwahongmun(華虹門)' through an investigation of the vicinity of their original landscapes at the time of construction of Hwaseong in Suwon and through tracing the transformative process of the environments of this vicinity. The results are as follows; As identified by 'Yongyunjung(龍淵亭)' and 'Yongdugak(龍頭閣)', other names of Yongyun, 'Banghwasuryujung(訪花隨柳亭)', which was built on 'Yongduam', is a facility whose place identity is highlighted with a sense of unity with Yongyun. The south lakefront of Yongyun, bordering Banghwasuryujung, has boundaries that make the best use of the natural geographical features of Yongduam while the current circumference of Yongyun is comparatively shorter than its original state. The size of 'Joongdo(中島)', however, seems to be an example of apparent over-design complement and reorganize 'Joongdo', which had been restored larger than its original state at the time of restoration in the 1970s. The depth of 'Yongyun' was created to be lower than the actual depth, without consideration for its initial depth, as soil was accumulated through continuous flooding after it was created. It is assumed that the original drains which were installed about 10m inside the lake were created facing the stream. As regards the planting environment, a circular planting of willows was made in the outskirts of 'Yongyun', except the 'Yongduam' which is a pure forest, and a mix of 'Pinus densiflora', shrubbery and deciduous broad leaf trees was planted in 'Joongdo'. Of the plants growing in the area of this study, plant species introduced to Korea after Hwaseong was constructed are found, most of which provide interest and attraction. The old pine trees growing in a group once grew in the castle areas of the vicinity even in the 1920s, the period of Japanese occupation, but they disappeared from the area in the aftermath of subsequent urban development and the Korean War. Although restored to the site, the number and space taken up by these trees are insignificant compared to those of the original environment. On the basis of these results, the following is considered necessary for the true restoration of the vicinity of 'Yongyun' and 'Hwahongmun': First, the grounds of 'Yongyun' should be dredged deeply enough to expose the bedrock and should be recreated in the rough outline of a half moon by extension to the southwest toward 'Yongduam' and 'Hwahongmun', and the size of 'Joongdo' should be significantly reduced. Secondly, considering that most plant species, except the pine trees and wild trees in 'Yongduam', are non-native plants introduced in order to provide such attractions such as the appreciation of scenic areas, they should be replaced with native species, mainly with the pine trees which were utilized during the construction of Hwaseong. The weeping willows planted in the 'middle-island' should be relocated to the outskirts of 'Yongyun', and replaced with pine trees as the major trees and maple trees or deciduous broadleaf trees to fill in the gaps. Thirdly, exotic species such as the 'Pinus rigida' planted in a group around 'Banghwasuryujung' and 'Bugammun' and 'Pinus strobus' planted in the vicinity of Hwahongmun' should be removed.

• Clinical and Experimental Pediatrics
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• v.52 no.2
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• pp.199-204
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• 2009

Purpose : Seizure associated with fever may indicate the presence of underlying inherited metabolic diseases. The present study was performed to investigate the presence of underlying metabolic diseases in patients with complex febrile seizures, using analyses of urine organic acids. Method : We retrospectively analyzed and compared the results of urine organic acid analysis with routine laboratory findings in 278 patients referred for complex febrile seizure. Results : Of 278 patients, 132 had no abnormal laboratory findings, and 146 patients had at least one of the following abnormal laboratory findings: acidosis (n=58), hyperammonemia (n=55), hypoglycemia (n=21), ketosis (n=12). Twenty-six (19.7 %) of the 132 patients with no abnormal findings and 104 (71.2%) of the 146 patients with statistically significant abnormalities showed abnormalities on the organic acid analysis (P<0.05). Mitochondrial respiratory chain disorders (n=23) were the most common diseases found in the normal routine laboratory group, followed by PDH deficiency (n=2) and ketolytic defect (n=1). In the abnormal routine laboratory group, mitochondrial respiratory chain disorder (n=29) was the most common disease, followed by ketolytic defects (n=27), PDH deficiency (n=9), glutaric aciduria type II (n=9), 3-methylglutaconic aciduria type III (n=6), biotinidase deficiency (n=5), propionic acidemia (n=4), methylmalonic acidemia (n=2), 3-hydroxyisobutyric aciduria (n=2), orotic aciduria (n=2), fatty acid oxidation disorders (n=2), 2-methylbranched chain acyl CoA dehydrogenase deficiency (n=2), 3-methylglutaconic aciduria type I (n=1), maple syrup urine disease (n=1), isovaleric acidemia (n=1), HMG-CoA lyase deficiency (n=1), L-2-hydroxyglutaric aciduria (n=1), and pyruvate carboxylase deficiency (n=1). Conclusion : These findings suggest that urine organic acid analysis should be performed in all patients with complex febrile seizure and other risk factors for early detection of inherited metabolic diseases.