• Applied Microscopy
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• 제28권4호
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• pp.513-525
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• 1998

The spermatogenetic process in the edible giant snail is similar to those in the other snails, except for the axoneme formation process. In this study, the axoneme formation process in the giant snail was mainly examined by means of electron microscopy. The tail portion of a spermatozoon is about $160{\mu}m$ long, and extends straight to the rear, surrounded by two large and long mitochondria in spiral forms. A number of glycogen particles $(40\sim70nm)$ are found in the swollen matrix of the mitochodria. The axoneme which composes the tail of a spermatozoon is surrounded by $7\sim10$ lamella-form fibrous sheaths of about $0.2{\mu}m$ in thickness. Most of the mature spermatozoa are found to be clustered into a group of $5\sim7$ ea in syncytial bridges formed by cytoplasmic processes. Sertoli cells contain glycogen particles, endoplasmic reticulum, a lot of mitochondria, and lipids in their cytoplasm. They protrude their filiform pseudopodia and phagocytize abnormal spermatids or spermaozoa.

• 대한임베디드공학회논문지
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• 제14권1호
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• pp.25-31
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• 2019

An underwater glider is a type of autonomous unmanned vehicle and it advances using a vertical zig-zag glide. For this purpose, the position of an internal battery is regulated to control its attitude, and the amount of water in a buoyancy bag is regulated to control the depth. Underwater glider is suitable for a long-distance mission for a long time, because the required energy is much smaller than the conventional autonomous unmanned vehicle using propeller propulsion system. In this paper, control of horizontal tail wing is newly added to the conventional battery position and buoyancy control. The performance of the proposed controller is shown through Matlab simulation.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.361-366
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• 2000

To make high precision cutting of long materials or a piston for the engines, it must be necessary to keep the stability of spindle and tail stock in CNC lathe. If a object is clamped at the ends, the thermal expansion and cutting generated in cutting process appear as the deflection of in cuttings objects. Especially, of a piston ring, piston ovality and piston profile, the influences are very serious. In order to solve the problems most of piston cutting are worked in simply support. However, the problems exist, yet.

• Asian-Australasian Journal of Animal Sciences
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• 제18권6호
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• pp.755-761
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• 2005

Blood samples were collected from eight native Japanese breeds of chickens (Miyadi-dori, Ohiki, Onaga-dori, Shoukoku, Tosa-Jidori, Tosa-Kukin, Toutenkou and Uzurao) and two foreign breeds of chickens (White Leghorn and Rhode Island Red) to examine the genetic variability and relationships among the breeds by using a microsatellite DNA technique. Except for the Shoukoku breed, the other Japanese chicken breeds all originate from Kochi Prefecture. Ohiki, Onaga-dori, Tosa-Jidori, Toutenkou and Uzurao are fancy fowl, and Miyadi-dori and Tosa-Kukin are utility fowl. Among the fancy fowl, Ohiki, Onaga-dori, and Toutenkou males have thick and long feathers in the saddle and tail. Genetic variabilities of the 20 microsatellites examined, varied depending on the breed: the mean number of alleles per locus ranged from 2.05 (Miyadi-dori) to 3.90 (Rhode Island Red); proportion of polymorphic loci ranged from 0.75 (Miyadi-dori) to 1.00 (Rhode Island Red, Shoukoku and Uzurao); and mean expected heterozygosity ranged from 0.330 (Miyadi-dori) to 0.607 (Rhode Island Red). Unique microsatellite alleles were detected in each breed. Using the neighbour-joining method, phylogenetic trees were constructed based on the genetic distances of D$_{A}$ and D$_{ST}$. Among the breeds originating from Kochi Prefecture, fancy and utility breeds belonged to different clusters. Among the fancy breeds, those having thick and long feathers in the tail and saddle showed a close genetic relationship to the Shoukoku breed, which also has thick and long feathers in the tail and saddle.

• Ocean and Polar Research
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• 제31권1호
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• pp.97-110
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• 2009

Two of the most important topics of the 21st century are ensuring harmony between man and his environment and the emerging long-tail economy in which niche markets are becoming increasingly more important. Since the Industrial Revolution in 17th century, human beings have increasingly exploited the world's natural capital, such as the natural environment and its ecosystems. Now the world is facing limits to sustainable economic growth because of limits to this natural capital. Thus, most countries are beginning to adopt a new development paradigm, the so-called"Green Development Paradigm" which pursues environmental conservation in parallel with economic growth. Recently, the Korean government announced an ambitious national policy of Low Carbon & Green Growth for the next six decades. This is an important step that transforms the existing national policy into a new future-oriented one. The fisheries sector in particular has great potential for making a substantial contribution to this national policy initiative. For example, the ocean itself with its sea plants and phytoplankton has an enormous capacity for fixing carbon, and its vast areas of tidal flats have a tremendous potential for cleaning up pollutants from both the sea and the land. Furthermore, the fishing industry has great potential for the development of fuel-saving biodegradable technologies, and a long-tail economy based on digital technologies can do much to promote the production and consumption of green goods and services derived from the oceans and the fisheries. In order for this potential to be realized, the fisheries authority needs to develop a new green-growth strategy that is practical and widely supported by fishing communities and the markets, taking into account the need for greenhouse gas reduction, conservation of the ocean environment and ecosystems, an improved system for seafood safety, the establishment of strengthened MCS (monitoring control surveillance) system, and the development of coastal ecotourism. In addition, fisheries green policies need to be implemented through a well-organized system of government aids, regulations and compensation, and spontaneous (voluntary) orders in fishing communities should be promoted to encourage far more responsible fisheries.

• 한국콘텐츠학회논문지
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• 제21권8호
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• pp.69-78
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• 2021

디지털 기술발전과 더불어 극장이 아닌 디지털 온라인 매체에서의 영화 수요와 공급이 지속적으로 증가하고 있다. 본 연구는 극장에 비해 다양한 영화가 상영되는 디지털 온라인 영화시장의 수요 집중화 경향을 분석하고자 한다. 2013년 1월부터 2019년 12월까지 TV VOD 자료에 대한 실증분석을 통해 다음의 결과를 확인하였다. 첫째, 극장개봉작 1,137편의 영화에 대한 분석을 통해 디지털 온라인 매체인 TV VOD 관람 수요에 비해 극장 관람 수요의 집중도가 상대적으로 더 높음을 확인하였고 이러한 차이가 통계적으로도 유의하게 나타났다. 둘째, TV VOD 수요 집중도 추이를 살펴보면, 시장에 공급되는 작품편수가 증가함에 따라 절대적 롱테일 지수에 해당하는 독립·예술영화(틈새 상품) 수요도 증가하는 추이를 보이지만 상대적 롱테일 지수인 독립·예술영화 수요 비중과 상위 1% 영화의 수요 비중의 경우 증가 또는 감소 추이가 뚜렷하게 나타나지 않았다. 셋째, TV VOD 수요 집중도와 TV VOD 시장규모 간에 통계적으로 유의한 관계가 있다고 보기 어려웠다. 본 연구는 우리나라의 디지털 온라인 영화시장의 특징을 파악할 수 있는 실증적 결과들을 제시하였다는 점에서 유용성을 가질 것이다.

• Parasites, Hosts and Diseases
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• 제22권1호
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• pp.30-36
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• 1984

An ultrastructural study on the mature spermatoBoa oi Cloptorchis sineitsis was carried out. For this study, the liver cukes were collected from the livers of rabbits and rats artificially infected with the metacercariae obtained from the fresh water fish, Pseudorasbora parve. Six-month old worms were used. The collected liver fiukes were washed with 0.85% saline solution and then immediately moved to cold 2% glutaraldehyde buffered with 0.1M Millonig's phosphate buffier (pH 7.4) . The materials were dissected into appropriate pieces in the fixative about 30 minutes after beginning of the fixation. Two hours later the materials containing the seminal receptacle were rinsed several times with the buffier and were secondarily fixed with cold, bugeyed 1% osmium tetroxide(OsO4) for 2 hours. The fully mixed tissue blocks Ivere dehydrated in a series of graded concentrations of acetone and were embedded in Epon 812 mixture. Thin sections obtained from LKB-5 ultramicrotome were stained with uranyl acetate and Reynold's lead citrate. Observations of the sections were carried out with JEM-100CX II electron microscope, In general, the mature sperm was long thread-like form with a sickle-shaped head. According to the longitudinal sectioned view of the sperm tail, the nucleus seemed to be spirally coiled and run a little far along the tail. The acrosome was not observed. The cytoplasm of the tail was biflagellated as usual in trematodes. Unlike other platyhelminth spermatozoa, the sperm tail of Clenorchis sinensis showed the ${\ulcorner}9+2{\lrcorner}$ in the microtubular arrangement. The mitochondria with poorly developed cristae were observed throughout the middle piece. The middle piece of the tail showed dull ladder or triangular shapes with the two flagella at the bottom. But, the principal piece of the tail was slightly flattened cylindrical shape with two aagella within the cytoplasm. The end piece was uniflagellated. It was not clearly identised whether the end piece was subdivided into two by aagellum or the lengths of the two aagella were different. The glycogen granules were rich in the cytoplasm throughout the lenght of the spermatozoa. These granules might be the energy source for the movement of the spermatosoa.

• 정보과학회 논문지
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• 제44권8호
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• pp.767-773
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• 2017

클라우드 데이터베이스와 같은 분산 시스템 환경에서는 균일한 서비스 품질을 보장하기 위해 꼬리 응답시간을 짧게 유지하는 것이 중요하다. 본 논문에서는 카산드라 데이터베이스를 대상으로, 긴 꼬리 응답시간에 해당하는 지연이 메모리 공간 부족으로 인해 발생한다는 것을 보이며, 이러한 지연이 메모리 공간 확보를 위해 버퍼에 저장된 데이터를 저장장치에 완전히 내려쓸 때까지 카산드라가 사용자의 요청을 받지 않기 때문임을 밝힌다. 버퍼에 저장된 데이터를 내려쓰는데 걸리는 시간은 저장장치 성능에 따라 결정되므로 SSD의 가바지 컬렉션으로 인한 성능 저하가 꼬리 응답시간을 더 길게 만들고 있음을 관찰하였다. 우리는 자바가상기계에서의 가비지 컬렉션과 SSD에서의 가비지 컬렉션을 함께 수행하여 SSD의 가비지 컬렉션 비용을 숨기는, SyncGC 기법을 제안한다. 실험 결과, SyncGC 기법을 통해 꼬리 응답시간인 $99.9^{th}$와 $99.9^{th}-percentile$을 각각 31%, 36% 줄일 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권10호
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• pp.1507-1514
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• 2017

Objective: The Bashang Long-tail chicken (BS), an indigenous Chinese breed, is considered cold tolerant. We selected BS, the Rhode Island Red (RIR), and their reciprocal crossbreds for the present study. The objectives were: i) to validate whether BS is cold tolerant and whether egg production and cold tolerance of crossbreds could be improved; and ii) to determine the physiological characteristics that underlie cold tolerance and favorable egg production performance in cold environments. Methods: A total of 916 chickens were reared in warm and natural cold environments (daily mean ambient temperature varied from $7.4^{\circ}C$ to $26.5^{\circ}C$ in the warm environment and from $-17.5^{\circ}C$ to $27.0^{\circ}C$ in the cold environment). To investigate their adaptability to the cold environment, the egg production performance and body weight were monitored and compared between breeds and environments. The cloacal temperature and serum biochemical parameters were monitored to reveal the physiological characteristics underlie cold tolerance and favorable egg production performance in the cold environment. Results: The warm environment experiment showed that RIR had the highest egg production performance, and that the reciprocal crossbreds had a higher egg production performance than BS. While in the cold environment RIR had the lowest egg production performance, and the reciprocal crossbreds had a higher egg production performance than BS. In the cold environment BS and reciprocal crossbreds had higher triiodothyronine, tetraiodothyronine levels than RIR. At 35 and 39 wk of age, when the ambient temperature was extremely low (varied from $-20^{\circ}C$ to $0^{\circ}C$), serum glucose, follicle-stimulating hormone, luteinizing hormone, estradiol of BS and crossbreds were higher than RIR. Conclusion: Bashang Long-tail chicken has a favorable cold tolerance ability. Crossbreeding with RIR and BS is an effective way to develop cold tolerant chickens with improved egg production performance.

• 한국가금학회지
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• 제38권2호
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• pp.81-87
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• 2011

초위성체(MS) 표지를 이용하여 한국 재래닭 집단의 각각의 분자유전학적 특성을 조사하고, 그 평가를 통해 한국 재래닭에 대한 품종 및 계통 분류의 기초를 마련하고자 본 연구를 수행하였다. 또한, 한국 재래닭 집단 내 및 집단간 유전적 변이성을 확인하고, 그 분류 및 특성 평가를 위한 MS 분석 체계를 마련하여 국내 가축유전자원의 관리에 활용코자 하였다. 국내 관리 기관 및 농가 보유 11개 계통의 한국 재래닭 및 상용계 462 수를 대상으로 19개 MS 표지로 분석한 결과, 한국 재래닭 집단은 상용계부터 분자유전학적으로 별개의 집단으로 구분되며, 특히 한국 재래닭 중 긴꼬리닭 계통은 상용계와 국내 토종닭 어느 집단과도 확연히 분리되는 것을 확인하였다. 한국 재래닭 집단 간의 유전거리는 0.11~0.18로 비교적 낮게 나타났으나, 유전적 균일도는 R 계통을 제외하고 0.86~0.88로 코니쉬 계통을 제외한 상용계의 0.95~0.97보다 비교적 낮았다. 다만, 긴꼬리닭 집단의 유전적 균일도는 0.91~0.97로 높게 나타났다. 본 연구를 통하여 한국 재래닭 집단 간의 유전적 차이 및 동질성, 그리고 집단내의 유전적 균일성을 확인하고, 긴꼬리닭 계통의 위치를 확인하였다. 이러한 결과는 국내 유전자원의 고유성을 인정할 수 있는 과학적인 근거로서, 국가 수준의 가축유전자원 평가, 관리의 기초자료로 활용될 수 있을 것이다.