• 한국멀티미디어학회논문지
• /
• 제12권1호
• /
• pp.130-138
• /
• 2009

컴퓨터와 함께 많은 시간을 보내는 현대인들 중에는 바탕화면과 화면보호기로 마음의 편안함을 주는 자연풍경이나 가상수족관 등을 설정하는 사용자들이 증가하고 있다. 가상수족관은 임의의 가상 해저환경에서 자유롭게 행동하는 여러 종류의 물고기를 만들고, 동작을 분석하여, 물고기들의 애니메이션 작업을 수행함으로써 만들어진다. 본 논문에서는 유체의 형태변화를 실시간으로 표현하는 유체 애니메이션 기법과 가상물고기의 다양한 속성에 따라 상호작용을 할 수 있는 Smart Fish기술을 이용하여 활용가치가 높은 실감형 가상수족관을 구축하는 방법을 제안했다. 본 논문에서 제안하는 방법은 다양한 해저환경을 표현하는 가상수족관, 수족관 화면 보호기, 물고기 육성 게임 등에 활용되어질 수 있다.

• Fisheries and Aquatic Sciences
• /
• 제11권1호
• /
• pp.61-69
• /
• 2008

Using empirical data of fish performance and physiological limits as well as physical stimuli and environmental data, a cod-end selectivity model based on a chaotic behavior model using the psycho-hydraulic wheel and neural-network approach was established to predict fish escape or herding responses in trawl and cod-end designs. Fish responses in the cod-end were categorized as escape or herding reactions based on their relative positions and reactions to the net wall. Fish movements were regulated by three factors: escape time, a visual looming effect, and an index of body girth-mesh size. The model was applied to haddock in a North Sea bottom trawl including frequencies of movement components, swimming speed, angular velocity, distance to net wall, and the caught-fish ratio; simulation results were similar to field observations. The ratio of retained fish in the cod-end was limited to 37-95% by optomotor coefficient values of 0.3-1.0 and to 13-67% by looming coefficient values of 0.1-1.0. The selectivity curves generated by this model were sensitive to changes in mesh size, towing speed, mesh type, and mesh shape.

• 한국동물위생학회지
• /
• 제20권3호
• /
• pp.307-312
• /
• 1997

To investigate the species and infection rate of Tripartiella sp in three species of freshwater fish, carp(Cyprinus carpio), goldfish(Crassius auratus) and Korean catfish(Parasilurus asotus), fish cultured in the fish farms next to Yosu and in the western area of Chunbuk province in Korea was examined from April to June, 1996. The infection rate was evaluated after observing the gill and mucous from 130 fish under the microscope. The species of Tripartiella was identified on the basis of the shape and number of denticle according to methods of Bychowsky(1985) after staining the parasites with 2% methyene blue solution. All the detected-parasite was classified as Tripartiella differed from Trichodina reported previously in our country. T carassii, T californica, T rhombi from Goldfish, T rhombi from common carp, T californica from Israeli carp and T bychowsky from Korean catfish were observed. In the fish from the fish farms in the western area of Chunbuk province, the infection rate of Tripartiella sp was ranged from 6.7% to 100%, but in neither carp nor goldfish from the farms next to Yosu the parasite detected.

• 수산해양기술연구
• /
• 제32권1호
• /
• pp.50-58
• /
• 1996

The authors carried out a field experiment to confirm the effect of underwater sound on the luring of fish schools in a setnet in the coast of Cheju Island. The effects of the acoustic emission on the luring of fish schools were observed using a manufectured underwater speaker in the setnet, and pure sound, of which frequency was 600Hz and the source level was 126dB, was emitted on and off at 5 minutes intervals in the set net during the night of ,July 29 and ,July 31. So we had recorded behavior of fish schools by the telesounder with two channel and shape of the setnet by underwater video camera and analyzed them. When the flood and ebb currents were around the setnet, the nets rised to the surface of water and it happened occasionaly at the stand of tide. Therefore, it was in the state that fish schools feel constraint to enter into the setnet, and was required a new design of the setnet stand up to strong tidal current. As the pure sound, of which frequency was 600Hz was emitted for the luring of fish schools in a setnet, the catch ammounts of fish, the young horce mackereWI'rachllrlls japonicus), was increased 4~6 times than not emitted.

• Journal of Nutrition and Health
• /
• 제29권2호
• /
• pp.166-176
• /
• 1996

Effect of fish oil feeding was investigated on morphological changes of thoracic aora in female rats after bilateral oophorectomy(OVX). Fifty four healthy female rats of Spraque-Dawley strain, were divided into sham group, OVX group and , OVX and fish oil feeding, group. Experimental animals were sacrificed at the end first, eighth week and sixteenth week after operation, thoracic aorta blood sample were collected. The results obtained were as follows ; 1) Total cholesterol and LDL-cholesterol contents in serum were significantly higher in the sham and OVX groups than fish oil feeding group. Serum HDL-cholesterol levels among three exjperimentnal group were lowest in the OVX group. 2) In the sham operation group, as experimental period prologed the endothelial cells were distorted round shape and enlarged, and the subendothelial layer was widened in tunical intima. The elastic lamina were disrupted in tunica group. In the fish oil feeding group, the endothelial cells and subendothelial layer in tunica intima, and the elastic lamina in tunica media were intance. From the present results, it was suggested that fish oil feeding may prevent the atherosclerotic changes in thoracic aorta and serum cholesterol induced by oophhorectomy in the rats.

• Proceedings of the National Institute of Ecology of the Republic of Korea
• /
• 제3권1호
• /
• pp.47-53
• /
• 2022

The escape behavior of prey fish to predator attack is directly linked to the survival of the fish. In this study, I explored the escape behavior of Medaka fish to bird attacks. To simulate the attack, I designed a model triangular-shaped bird to slide along a fishing line connected between rods at both ends of the tank. The triangular shape was set to 10×15 (S=1), 15×20 (S=2), and 20×25 cm (S=3) with base×height. The slope (θ) of the fishing line, which determines the attack speed of the model bird, was set to values of 15° (θ=1), 30° (θ=2), and 45° (θ=3). The escape behavior was characterized using five variables: escape speed (ν), escape acceleration (α), responsiveness (γ), branch length similarity entropy (ε), and alignment (ϕ). The experimental results showed when (S, θ)=(fixed, varied), the change in values of the five variables were not significant. Thus, the fish respond more sensitively to S than to θ In contrast, when (S, θ)=(varied, fixed), ν, α, and γ showed increasing trends but ε and ϕ did not change much. This indicates the nature of fish escape behavior irrespective of the threat is inherent in ε and ϕ. I found that fish escape behavior can be divided into two types for the five physical quantities. In particular, the analysis showed that the type was mainly determined by the size of the model bird.

• 동의생리병리학회지
• /
• 제23권1호
• /
• pp.34-40
• /
• 2009

After a research on appearance diagnosis and fish, bird, horse, and turtle types, this study concluded as following. Appearance diagnosis is a technique that exams five jang organs by color and shape of eye, nose, mouth, and ear. Four HyungSang types-including fish, bird, horse and turtle types-are evaluated upon the external shape that are created while type of seed changes. Appearance diagnosis focuses on five jang organs. Four HyungSang types focus on external shape, but are eventually related to five jang organs. Thus, two different techniques possess a point in common; five jang organs. The assignment of nose, eye, ear and mouth to the Five elements varies between two techniques. On the viewpoint of formation, appearance diagnosis assigns them to metal-water-wood-fire-earth and movement, and four HyungSang types do to wood-fire-earth-metal-water and constitution. On the viewpoint of body/use and static/dynamic, appearance diagnosis assigns them to metal-water-wood-fire-earth and constitution, and four HyungSang types do to wood-fire-earth-metal-water and movement. If nose, eye, ear, and mouth are assigned by on four HyungSang types, which are based on external shape, the assignment can be utilized in diagnosis. If, however, they are assigned by appearance diagnosis, it can be focus on treatment. Five jang organs and six fu organs are affected by internal conditions because they are located inside of human body, while four HyungSang types are affected by external conditions because it deals with external shape. If a disease occurs in the developed part of the body, it would be difficult to be cured because four HyungSang types depend on external shapes.

• 한국기계가공학회지
• /
• 제16권2호
• /
• pp.129-134
• /
• 2017

The process of producing a fish trap frame is very complicated and manual, so it is expensive, the quality of the product is unstable, the quality is not guaranteed, the durability is weak, and it cannot be used for a long time. Therefore, we made a fish trap frame-making machine to reduce the manpower and costs and to make robust products. This machine cuts the wire of mild steel to a certain size and then makes the connecting parts into a trapezoid shape by spot welding. In this study, the weld point shear strength between manual and automatic operation was compared and analyzed.

• Applied Microscopy
• /
• 제44권1호
• /
• pp.1-7
• /
• 2014

The spermatogenesis of Siamese fighting fish, Betta splendens, belongs to Osphronemidae was investigated by light and electron microscopic observations. In primary spermatocyte stage, the nucleus was comparatively large ellipsoidal, and mitochondria showed a marked development in cytoplasm. In secondary spermatocyte stage, the germ cells were smaller than that of primary spermatocytes. The nucleus was a spherical shape and intercellular space was formed between germ cells. In spermatid stage, the early spermatids were not much different from a secondary spermatocyte. But, the chromatin condensation was occurred from the outside to the inside. The nucleus was more condensed. Intracellular space was larger than early spermatid. The mitochondria were rearranged in a middle piece, and occupied about half of the head part in early sperm. In sperm stage, the head of mature sperm was a spherical shape and had no acrosome. The flagellum was showed the typical 9+2 array of microtubules. Also, the tail of sperm had no lateral fins and outer coarse fibers. These ultrastructural characteristics can be used in classification of species.

• Smart Structures and Systems
• /
• 제10권6호
• /
• pp.501-515
• /
• 2012

We design and test a shape memory alloy (SMA)-based actuation system that can be used to propel a fish robot. The actuator in the system is composed of a 0.1 mm diameter SMA wire, a 0.5 mm-thick glass/epoxy composite strip, and a fixture frame. The SMA wire is installed in a pre-bent composite strip that provides initial tension to the SMA wire. The actuator can produce a blocking force of about 200 gram force (gf) and displacement of 3.5 mm at the center of the glass/epoxy strip for an 8 V application. The bending motion of the actuator is converted into the tail-beat motion of a fish robot through a linkage system. The fish robot is evaluated by measuring the tail-beat angle, swimming speed, and thrust produced by the tail-beat motion. The tail-beat angle is about $20^{\circ}$, the maximum swimming speed is about 1.6 cm/s, and the measured average thrust is about 0.4 gf when the fish robot is operated at 0.9 Hz.