• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.454-461
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• 2017

This study was conducted to investigate the optimal conditions for spore germination, prothallus propagation, sporophyte formation, and seedling growth in Polystichum braunii (Spenn.) $F{\acute{e}}e$. The rate of spore germination and early prothalium development was high in Knop (41.2%), which had low mineral content. The optimal medium for prothallus propagation and sexual organ formation was 2MS medium (2% sucrose). Among the various mixtures of cultivation soil (bedding soil, peat moss, perlite, and decomposed granite), a mixture of bedding soil and decomposed granite at a ratio of 2:1 (v:v) had a positive effect on sporophyte formation (276.3 ea/$7.5m^2$). The most efficient conditions for promoting the growth of sporophytes were pots filled with only bedding soil.

• Journal of Applied Biological Chemistry
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• v.63 no.3
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• pp.181-188
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• 2020

In this study, Tongue fern (Pyrrosia lingua) plants that have been used traditionally as medicines. Their traditional medicinal uses, regions where indigenous people use the plants, parts of the plants used as medicines. This study was designed to assess the antioxidant and inhibition activities of extracts from P. lingua. In the P. lingua extracts was measured ethanol activity, 80.0% ethanol was high activity. The antioxidant activity was measured in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-Azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), assays. DPPH and ABTS radical in this experiment, solid and phenolic of extract were tested, but only an average concentration of 100 ㎍/mL was used. However, the phenolic extract is shown phenolic activity reached a peak. Also, phenolic extracts ware reached peak water and ethanol extracts. As a result, using the phenolic extracts did other antioxidant assays such as DPPH, ABTS, protection factor, and thiobarbituric acid reactive substances at 50-200 ㎍/mL concentrations. The activity of elastase and collagenase, inhibiting their activities may retard skin aging. α-Glucosidase and α-amylase, inhibitors need to be explored for the benefit of postprandial hyperglycemia in diabetic patients. Activities of tyrosinase, hyaluronidase and xanthine oxidase inhibitors of these enzymes are increasingly important ingredients in cosmetics and medications to protect the skin against hyperpigmentation and skin aging. Inhibition effects were investigated using the P. lingua extracts at 50-200 ㎍/mL concentrations. The expression levels of enzyme inhibitions activities were decrease in dependent-concentrations manner when P. lingua extracts were treated.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.661-670
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• 2019

In this study, we constructed a model of an area where the production and production amount of wild vegetables which are designated as short term income forest products for the whole country are self-sufficient for the representative Eastern Braken fern(Pteridium aquilinum)and Edible aster(Aster scaber). The difference between the existing cultivation site and the model result was examined, and the distribution of the cultivable area was simulated according to the near future climate change by the 2050s. The degree of agreement between the cultivated area and the actual native area was very low at 14.5% for Eastern Braken fern and 12.9% for Edible aster. Using the Maxent model, which has already been proven by many research examples, the cultivation maps through the model can guarantee statistical accuracy by considering many variables. To analyze future location changes, the RCP 4.5 scenario and the RCP 8.5 scenario were applie Edible aster d to predict potential future cultivable areas and compare them to the present. There was no decrease in the cultivable area due to climate change nationwide. However, in the RCP 8.5 scenario for Eastern Braken fern and the RCP 4.5 scenario for Edible aster, declining areas such as Gangwon-do, Jeollabuk-do and Gyeongsangbuk-do showed prominence according to the scenarios. The result of this study suggests that various models can be used for the production of short-term forest productivity maps and it will be used as a climate change impact assessment data for competitive forest products considering the influence of future climate change.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2005.05a
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• pp.117-117
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• 2005

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.287-290
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• 1990

The paper describes the correction of the switching dead times avoiding a bridge leg short circuit in pulse width modulated voltage sorce inverters. The co consequences on AC variable speed drives with synchronous and asynchronous motors are described by harmonic analysis and by computer simulation.

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.222.2-222
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• 2003

No Abstract, See Full Text

• Korean Journal of Plant Taxonomy
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• v.42 no.2
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• pp.167-170
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• 2012

During the course of the execution of the project entitled Distribution Research of Rare Plants, we found the habitats of two rare ferns with obscure and/or extremely restricted distribution ranges, as previously unreported habitats. A subantarctic fern reported on Hamgyeong-do and Gangwon-do, Dryopteris coreano-montana Nakai, was found on Mt. Ibam in Jangseong-gun, Jeollanam-do. A subtropical fern reported south of Jeju-do, Dryopteris decipiens (Hook.) Kuntze, was newly found on Mt. Cheongwan of Jangheung-gun in Jeollanam-do.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.52-55
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• 2013

본 논문은 Boosted Random Ferns 기반의 회전 불변 얼굴 검출 방법을 제안한다. 기존 Random Ferns 의 경우 특징값을 추출할 때 임의로 선택한 두 픽셀의 밝기값 비교를 통하여 이진 특징값을 추출한다. 이 경우 해당 픽셀의 밝기값에 잡음이 포함되면 특징값이 부정확하게 추출되는 문제가 있다. 본 논문에서는 이러한 문제를 해결하기 위하여 임의로 두 블록을 선택하고 해당 블록내 밝기값의 평균을 비교하여 이진 특징값을 추출하였다. 또한 픽셀 위치를 임의로 선택하여 ferns 를 구성하였던 기존의 방법 대신 최고의 분류 성능을 가지는 fern 들을 이용하여 분류기를 구성하기 위해, AdaBoost 의 방법을 Random Ferns 에 맞게 변경하였다. Boosted Random Ferns 를 트리 구조의 cascade 노드에 방향과 각도에 따라 배치하여 연산 속도를 향상시키고 false-positive를 줄이는 효과를 보았다. CMU Rotated Face Database 를 사용하여 평가하였을 때, 기존 Random Ferns 는 false-positive 의 수가 57 개 일 때 66%의 검출률을 보인 반면, Boosted Random Ferns 는 false-positive 의 수가 45 개 일 때 88%의 검출률을 보였다.

• Korean Journal of Plant Taxonomy
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• v.49 no.1
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• pp.8-12
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• 2019

Although Myanmar is a biodiversity hotspot, little is known about its flora, particularly lycophytes and ferns, due to a lack of intensive inventories. In 2017, work on a total of 299 species of lycophytes and ferns found throughout the country, including 84 species from Natma Taung National Park in the Chin State, was published. However, a comparison of the flora of Myanmar with those of adjacent countries suggests that many more species are likely also to be distributed in this country. In the present study, two field surveys conducted in Natma Taung National Park during 2015 to make a checklist of lycophytes and ferns resulted in the discovery of three fern species not previously recorded in the flora of Myanmar. All occur in other countries in Southeast Asia as well as in other tropical areas. These species are Pteris bella (Pteridaceae), Dryopteris lepidopoda (Dryopteridaceae), and Loxogramme duclouxii (Polypodiaceae). The results will provide valuable information for the Myanmar fern checklist that is currently being prepared.

• Korean Journal of Plant Taxonomy
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• v.52 no.1
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• pp.24-28
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• 2022

Pteris griffithii Hook., one of the rarest fern species on the Indian subcontinent, is reported from Bhutan for the first time. The identity of this species was confirmed through morphological determination at the National Herbarium (THIM) of the National Biodiversity Centre (NBC) of Bhutan. It was found only in one location, in Gyelpozhing in eastern Bhutan, at an elevation of 521 m a.s.l. on 10 January 2016. Given that a very limited study of this species was conducted, the knowledge baseline with regard to its distribution is poor. It is also reported that this species has not been found for several years. The species is also considered to be very rare or critically endangered in some countries; however, there are no assessments on the International Union for Conservation of Nature (IUCN) Red List for this particular species. This paper attempts to provide baseline information considering its rarity and data deficiency. This species is also reported from the adjacent neighboring Indian state of Arunachal Pradesh as very rare, and also from Myanmar; however, confirmation of its presence in China is not clear at this time. Therefore, considering its data deficient status, we attempt to document it scientifically to create a knowledgebase pertaining to this particular species. Concurrently, this species merits further research to understand its distribution patterns in Bhutan and any related anthropogenic threats.