• Journal of fish pathology
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• v.25 no.3
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• pp.231-241
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• 2012

Diagnostic monitoring in fish farms with land-based tanks and netpen cases were conducted in eastern, western, southern and Jeju island of Korea during summer of 2007~2011. In total, 2413-fish samples of 4 marine fish species were tested for the detection of bacteria and parasite. Fish species tested were olive flounder (Paralichthys olivaceus), black rockfish (Sebastes schlegeli), red sea bream (Pagrus major), pacific white shrimp (Litopenaeus vannamei). During the diagnostic monitoring from 2007 to 2011, the infection rates by single infection of bacterial or parasitic pathogens were relatively higher than the mixed infections. The main bacterial pathogens in olive flounder, black rockfish and pacific white shrimp were Vibrio spp. (V. harveyi, V. ichthyoenteri, Vibrio sp.). The main bacterial pathogens in red sea bream were also Vibrio sp. and Photobacterium damselae subsp. damselae. The main parasitic pathogens were both Miamiensis avidus and Trichodina sp. in olive flounder, Microcotyle sebastes in black rockfish, Microcotyle tai in red sea bream and Zoothamnium sp. in pacific white shrimp.

• Journal of Korea Entertainment Industry Association
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• v.13 no.8
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• pp.151-156
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• 2019

In recent years, the Korean realistic theme of the film momentum gradually rising. Realistic films do not stick to the business and market, and do not simply cater to the audience's needs for watching movies. They reflect social violence and cruel reality, allowing the audience to observe the structural contradictions in reality and think about the direction when watching movies. At the recent cannes film festival, "parasite" won the top prize palm in cannes by an overwhelming margin, with the highest score of 3.3 issues. Although this film is positioned as a thriller with comedy elements, it presents the opposite life images of Korean classes to the audience in a parasitic way, which not only expands the possibility and artistry of realistic film aesthetics, but also enhances the appreciation of the film and gives play to its own aesthetic value. Focusing on the technical and literary nature of the film, and having a high degree of attention to real life, it is an excellent work that tells about class opposition and thinking about reality. This paper considers and analyzes the content, form and creation method of parasite, and discusses the continuous exploration and attempt of realistic film to image language under the demand of market and system, evolving into new aesthetic expression.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.255-265
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• 1996

토양에 존재하는 진균인 Gliocladium virens는 식물병을 감소 또는 방제할 수 있는 생물학적인 특성에 의하여 G. virens는 지난 수십년간 실용가능성이 큰 생물학적 방제균(또는 길항균)으로 집중적으로 연구되었다. 이 균이 식물병의 발생을 감소시키는 생물적 방제효과는 항생작용, 중복기생, 근권에서의 생존과 집단번식, 뿌리표면에서의 정착 등에 의한 것으로 분류되고 있다. 특히, 항생물질인 gliotoxin, gliovirin, viridin 등은 Rhizoctonia solani 및/또는 Pythium spp. 등에 항생효과가 뚜렷하고, 식물병의 발생과 직접적인 상관관계를 나타내고 있어 G. virens의 식물병의 방제에 관련된 중요한 작용기작으로 제시되어 있다. 또한, 근권에서 이균의 생존과 집단증식 및 뿌리표면에서의 정착은 식물병의 방제와 상관관계를 나타낼 수 있는 중요한 작용기작으로 제시되고 있다. 그러나 이균이 R. solani 등에 기생하는 현상은 식물병의 생물적 방제의 직접적인 연관관계를 나타내고 있지 않다. G. virens을 이용의 생물적 방제효과를 증진시키기 위한 방법으로 다음과 같은 두 가지 방법을 들 수 있다. 첫째, 길항효과가 높은 G. virens 균주를 선발하기 위하여 여러 종류의 토양에서 길항력이 높은 G. virens의 선발이 지난 수십년간 진행되고 있다. 또한, 특정 길항효과를 발현하는 유전자를 G. virens의 염색체에 도입하고 이를 발현시킴으로써 생물적 방제효과를 증진시키는 것으로 이러한 방법은 1980년 후반부터 진행되고 있다. 둘째, G. virens의 길항효과가 최대의 효율로 발현될 수 있도록 최적의 미세환경을 갖추고 있으며 농민이 편리하게 사용할 수 있는 G. virens의 운송매체의 개발이 중요하다. 운송매체의 개발에 의한 'Glioguard'는 G. virens의 포자를 alginate 입자에 제형화한 것으로서 미국에서 시판되고 있다. Aldicarb, metalaxyl, atrazine 등의 농약을 분해할 수 있는 능력은 G. virens의 다른 생물적 특성중의 하나이다. 특히, parathion을 분해할 수 있는 Flavobacterium sp.의 유전자(opd)가 G. virens의 염색체에 도입되여 발현될 수 있는 방법이 제시되었으며, 이는 G. virens을 이용한 토양에서의 특정한 농약의 분해효율을 증진시킬수 있는 가능성을 제시한 것이다. 그러나, G. virens를 이용한 농약의 생물적 분해에 관한 연구는 기초단계로 평가되고 있으며, 포장에서 이를 실용화하기 위해서는 향후 지속적인 연구가 필요하다.

• Journal of fish pathology
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• v.26 no.2
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• pp.65-75
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• 2013

Population growth equation of scuticociliate Miamiensis avidus was obtained from the experimental results of in vitro culture condition to estimate the growth rate and carrying capacity from the growth equation. In addition, intraperitoneal infections into olive flounder Paralichthys olivaceus were carried out into 2 different conditions: different concentrations of M. avidus in same water temperature and same concentration of M. avidus in different water temperatures. Olive flounder mortality was threshold dependent with both the temperature and M. avidus density parameters. In this paper, we propose a mathematical model to study M. avidus growth in olive flounder based upon the interactions between parasite and host. The mathematical model was logistic growth differential equation (1.2). The parameters were found with Matlab program through the Levenberge-Marquardt method. In theorem, equilibrium values between the infected fish population and dead population could found. Our equilibrium points were a stable equilibrium and an unstable equilibrium. From the equation (1.6), it was possible to predict the amount of cumulative mortality of olive flounder along with the time after M. avidus infection.

• Journal of fish pathology
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• v.12 no.2
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• pp.101-105
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• 1999

In a survey of net-caged yellowtail Seriola quinqueradiata in the southern parts of Korean Peninsula, we found infestations of ciliate in the gills of the moribund fish during the abnormally elevated temperature. The ciliate was very similar to genus Colpoda Muller, 1773 on morphological and reproductive characteristics. Histopathological changes revealed that the ciliate invaded gills only, causing extensive destruction of the gill filaments including lamella without any clinical signs found in the other organs and tissues. This is the first record of the parasitic ciliate in cultured yellowtail.

• The Transactions of the Korean Institute of Power Electronics
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• v.4 no.1
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• pp.19-25
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• 1999

To achieve high efficiency in high power and high frequency applications, reduction of switching losses and noise is very important. In this paper, an improved zero voltage switching forward dc/dc converter is proposed. The proposed converter is constructed by using energy recovery snubbers in parallel with the main switches and output diodes of the conventional forward dc/dc converter. Due to the use of the energy recovery snubbers in the primary and secondary side, the proposed converter achieves zero-voltage-switching turn-off without switching losses for switching devices and output rectification diodes. The complete operating principles and experimental results will be presented.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.499-501
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• 2008

본 논문은 공진요소를 포함한 고전압 플라이백 컨버터의 설계 절차를 제시하는 것으로써, 고압 플라이백 컨버터 설계 시 기존 플라이백 컨버터의 Power Stage 설계 식을 적용하였을 때 원하는 출력 전압을 얻지 못한다. 고전압을 발생시키기 위한 고전압 플라이백 변압기는 2차 측의 많은 권선수와 높은 전압 때문에 기생 커패시턴스(parasitic capacitance)가 매우 크고, 과도상태에서 컨버터 전류 및 전압의 기생 공진(parasitic resonance)이 심각하게 발생한다. 이러한 공진요소를 고려하여 고전압 플라이백 컨버터의 특성을 해석하고 설계 절차를 제시한다. 이를 통해 고전압 플라이백 컨버터의 소형화 및 경량화를 도모하고, 고압 전원장치의 기술 축적을 위해 연구되었다. 제안된 회로의 동작원리를 설명하고, 타당성을 실험을 통하여 검증한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.11
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• pp.873-880
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• 2020

In this paper, we propose a guidance filter to estimate line of sight rate with strapdown seeker measurements and INS(Inertial Navigation System) information. The measurements of proposed guidance filter consisted of the LOS(Line of Sight) and relative position that can be calculated with the seeker's measurements, INS information and known target position, also the filter is based on an asynchronous filter to use outputs of the two sensors that are out of synchronous and period. Through the proposed filter, we can reduce the effect on parasitic loop that can be caused by using large time delay seeker and improve the estimation performance.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.4
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• pp.399-402
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• 2016

We propose a thin electromagnetic wave absorber using varactor diodes combined with intentionally introduced multiple slits, which enables continuous sweep of an absorption frequency band throughout relatively wide frequencies. The absorption frequency range of conventional electrically tunable absorbers has been restricted by high capacitance of varactor diodes. In order to overcome the problem, we introduce parasitic capacitance and connect them with varactors in series, which reduces the total capacitance dramatically. As a result, we can raise the operating absorption frequency up to the X-band region. Moreover, we can also control the operating frequencies by modifying the number of slits with little change in an entire frequency sweep range. Good agreement between simulated and measured results show the validity of our proposal.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.14 no.3
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• pp.165-170
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• 1981

Recently an unknown microbial desease and some parasitic crustaceans are prevailing in the sea-weed farms of Uudaria pinnatifida along the south-eastern coast of Korea.(1) Green spots probably caused by the microbial pathogens were found on the fronds of Undaira Pinnatifide. Particularly they were densely distributed on the distal half of the fronds. The tissues of the green spot area rot off, and small holes with green colored margin are formed. The holes at the distal part of the fronds are enlarged and they finally coalesced each other. Then this process accelerates decaying of the distal ends of the fronds.. The fronds growing in the central part of the farms are usually severely damaged, whereas in the marginal area of the farm toward the open sea side the damage is less serious. An examination revealed that the deseased fronds bore a number of viable bacteria, $6.8\times10^5\;to\;1.2\times10^6$ per gram at $15^{\circ}C$, whereas the healthy fronds $1.1\times10^4$. Twenty-six kinds of colonies, 247 strains of bacteria, were isolated from deseased fronds, belonging to Moraxella, Achromobacter, Vibrio, Flavobacterium, Acinetobacter, Pseudomonas, etc. (2) Pinholes occurred in one series on the frond. They were probably caused by a harpacticoid copepod, Thalestris sp. Seven years ago when the disease was first found to occur the copepod was observed on the fronds from March of the year. Recently, however, they have been found as early as December of the previous year. (3) A gammarid amphipod, Ceinina iaponica, invades the pith of the midrib through holdfast of thalli. This rarely causes the longitudinal seperation of the entire frond through the midrib as they bore a tunnel in the pith. Sometimes holdfasts of tile heavy damaged thalli make the frond departed from the substrate.