• Journal of Aquaculture
• /
• v.11 no.2
• /
• pp.141-149
• /
• 1998

Spawning inducement of striped knife-jaw, Oplegnathus fasciathus, was attempted by two experiments. In experiment I (Exp. I), water temperature was gradually increased from 14.5$^{\circ}C$ in December 15, 1996 to $21.0^{\circ}C.$ in February 22, `997 and then maintained at this level. Photo-period was also gradually increased from 10.5L/13.5D in December 15, 1996 to 15.5L/8.5D in February 17, 1997, and then maintained at this level. In experiment II (Exp. II), water temperature was increased in the same way from Exp. I. Photoperiod was natural conditions from December 1996 to March 9, 1997, and then suddenly increased to 15.5L/8.5D until the end of experimental period. Spawning of the fish was occurred from February 22 through April 2, 1997 (for 40 days) in Exp. I. Number of total spawned eggs was 30.04 million and fertilization rate was 77.2%. The fish began to spawn at $21.0^{\circ}C.$ and 15.5L/8.5D. It requied 65 days to spawn since the water temperature had increased from $14.5^{\circ}C.$ to $21.0^{\circ}C.$. Spawning of the fish was not occurred until March 9, 1997 in Exp. II. After 7 days, photo-period was suddenly incresed to 15.5L/8.5D and fish were spawned from March 17 through April 4, 1997 (for 20 days). Number of total spawned eggs was 21.28 million and fertilization rate was 72.1%. The fish began to spawn at $21.0^{\circ}C$ and 15.5L/8.5D. It required 65 days to spawning since the water temperature had increased from $14.5^{\circ}C$ to $21.0^{\circ}C$.

• Journal of Marine Life Science
• /
• v.7 no.2
• /
• pp.139-144
• /
• 2022

This study aims to investigate egg quality changes and free amino acid composition. Factors that can affect egg quality about farming conditions were investigated through biochemical analysis of egg by red spotted grouper, Epinephelus akaara. As a result, the buoyant, fertilization embryonic survival and hatching rate were better when reared in sea cage than in tank. And the content of free amino acid in fertilized eggs reared in sea cage was higher then in tank. In conclusion, fertilized eggs with good egg quality can be produced when farming sea cage, and contained more free amino acid.

• The Journal of the Korea Contents Association
• /
• v.20 no.3
• /
• pp.661-670
• /
• 2020

The purpose of this study was to investigate the incidence of sports injury and trend of incidence pattern of national judo athletes. The research method was analyzed based on the records of all injuries experienced by national judo athletes during training and competition for 9 years from 2008 to 2016. A total of 20,345 sports injuries requiring physical therapy were 10,768 (52.93%) for women, 9,577 (47.07%) for men, lower extremities 9,688 (47.62%), upper limbs 5,807 (28.54%), and trunk 4,850 (23.84%) and knee-related injuries (27.82%) occur more frequently than other injuries. Shoulders, feet and back were more frequent in male athletes, and ankle, neck and hand injuries were more common in female athletes. Using the binomial trend line, the trend of the decrease of sports injuries in each area was shown. However, infrequent injuries such as hands and hips tend to increase gradually. The results of this study are expected to be used as a training program for judo athletes' sports injury and basic data.

• Journal of Aquaculture
• /
• v.21 no.2
• /
• pp.107-110
• /
• 2008

This study was conducted to evaluate extruded pellet for the growth of grower Korean rockfish Sebastes schlegeli. Two replicate groups of 150 fish per each tank(initial mean weight 112 g) were fed one of four experimental extruded pellets for 8 months. Survival was 100% in all groups. Final mean weight, feed efficiency and protein efficiency ratio, feed intake and hepatosomatic index were not significantly different among all groups. Proximate compositions of the whole body and liver were not significantly different among all groups. It can be concluded that the dietary formulation used in four extruded pellets could be applied in the practical extruded pellet for grower Korean rockfish.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.31-38
• /
• 2008

This Study discussed the roll forming process analysis of levitation rail for urban Maglev vehicle. To verify validity of roll forming process, we analyzed roll forming process for track shoe which is similar to levitation rail. The analysis process was composed of 12 passes and was performed for only 8 passes except overlapping passes. In the variation of temperature with each pass, surface temperature of the structure was cooled from initial $1200^{\circ}C$ to $1010^{\circ}C$ during 30 second before first pass, and central temperature and surface temperature was cooled to $980^{\circ}C$ and $900^{\circ}C$ in final pass, respectively. A length of structure after final pass is about 5 times longer than that before roll forming process. A strain of structure had a higher value in the inner part of the track shoe and show from minimum 2.5 to maximum 6.5. A torque applying on roll appear high in 2, 3 and 4 passes and a maximum value was $27,000ton{\cdot}mm$. Also it was analyzed that a load to the normal direction needs maximum 300ton.

• Journal of Digital Convergence
• /
• v.11 no.4
• /
• pp.415-430
• /
• 2013

In the present study, injuries in Taekwondo athletes during training and competitions was investigated via questionnaire. The purpose of this research lies in encouraging Taekwondo instructors and trainees to take precautions against injuries furnishing a variety of data obtained by analyzing the causes of injuries by region with ones undergoing a training. Understanding how frequently trainees get injured by region. we will be able to promote safety. which is such a meaningful move to improve training condition. The subjects of this study were 413 playes at the gym focusing on South Chungcheong province. Questionnaires for taekwondo players had the results as follows. The research reveals that physical injuries among Taekwondo athletes are caused by various reasons, regardless of sex and grade, and that the injures are repeatedly occurring, Therefore, in order t prevent and minimize the occurrence f injuries among Taekwondo athletes, not only the athletes but also trainers, business administrators, and educators need to pay careful attentions and take necessary measures accordingly. Also, pre-education on precaution against injuries must be put into practice thoroughly and an environment in which the inured could receive swift first aid treatment as well as follow-up measures shall be formed. this, in the end, is expected to contribute in improving not only the health of the athletes but also their performances in matches.

• 정보화사회
• /
• s.169
• /
• pp.28-31
• /
• 2004

우리나라 정보통신은 불과 20여년만에 국가경쟁력을 선도하는 성장엔진으로 자리매김하였다. 최근 발표된 2004년 IMD의 국가경쟁력 평가 결과 우리나라 20대 강점 분야 중 IT관련 사항이 4개“나 포함되어 있으며, 아울러 IT산업은 연평균 GDP 성장률 8.3%를 상회하는 18.8%(‘98-’03)의 고도성장을 이루었고, 우리나라 전체 수출의 30%(‘03: 1,938억불 중 576억불)를 IT수출이 차지하는 등 경제발전을 주도하는 국가 주력산업으로 부상하였다.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.1028-1032
• /
• 2005

Due to excessive city's Traffic jam, which an energy and pollution problem of metropolis have risen seriouly, Many industrialized countries have developed many kind of new transportation system for the purpose of substituting the mass traffic. Maglev system has began the revenue operation from Japan and China recently and it is beginning highlighted the new system. We examined specification to be improved in the system and safety of maglev.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1993.04b
• /
• pp.166-171
• /
• 1993

절삭공구에의한 절삭가공은 오늘날 가장 보편화된 가공기술중의 하나이다. 그런데, 최근들어 각종 첨단산업의발전과 함께 초정밀 부품제작이 필수선결 조건으로 부상하고 있으며, 이에대한 해결방안중의 하나로 초정밀가공 기 술로 크게 대두되고 있다. 최근 컴퓨터 기술의 발달에 따라 구조해석분야의 해석방법론의 개발 및 보완에 힘입어 Klemecki(1973)에 의해유한요소법을 이용한 Chip생성기구 해석에 관한 연구가수행되었으며, Stevenson(1983) 등에의해단열조 건하에서 변형률과 온도 상태에서의 Chip형상, 잔류응결-변형율에 대한 연구가 이루어졌다. 본 연구에서는 유한요소법을 이용하여 미소절삭기구를 모델링하고, 절삭인자규명을 중심으로 응력-변형률 해석을 실시함으로써, 미소절삭시의 Chip 생성기구 및 전단면 생성 원리, 공구와 Chip간의 마찰기구의 고찰을 통해기본 Mechanism 이해와 적절한 절삭유한요소모델 제시의 기초자료로 삼고자 한다. 특히 본 보고서에서는 미소 절삭기구의 적정한 Constitutive Deformation Law 마찰계수 등 주요절삭인자변경에 따른 미소절삭기구 해석에 주안점을 두어 연구한 결과를 기술하였다.

• Journal of Aquaculture
• /
• v.9 no.3
• /
• pp.287-291
• /
• 1996

[ $F_2$ ] generation of gynogenetic diploids were produced in olive flounder, Paralichthys olivaceus, by brother-sister mating with full-sibling gynogenetic diploids ($F_1$). The induced ovulations and spawnings were conducted by using intraperitoneal injections of HCG (2,000 IU/kg body weight) with photoperiod controls. Floating rates of artificially ovulated eggs were ranged from 22.9 to $65.7\%$. Fertilization and hatching rates were ranged from 69.0 to $86.2\%$ and 36.8 to $85.8\%$, respectively. All of those three rates between two experimental groups were not significantly different (P>0.05). Average survival rates of $F_2$ generation of 40-day-old 효nogenetic diploid larvae were slightly lower than those of controls (P<0.05), however growth rates were much higher than those of their diploid controls.