• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.3
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• pp.214-224
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• 2004

A large cage system for the purpose of fishes farming in the open sea was influenced by various forces from the ocean environment. The deformation of the cage by these forces affects the safety of the cage itself, as well as that of the cultivated creatures. In this research, theoretical model was established to analyzing dynamic movement influenced by current for cage. Also, to increase the accuracy of calculations, the reduction ratio of flow speed acquired using the flume tank experiment. Applying the reduction ratio of flow speed to the numerical calculation, the calculation values were compared with the measured values in the flume tank experiment using cage model. The results were as follows ; 1. When the flow speed of the flume tank is fixed, the decrease of the velocity of flow which is passed the upper panel side is proportion to the increase of porosity ratio of netting. 2. When the porosity ratio is fixed, the increase of the velocity of flow which is passed the upper panel side is proportion to the increase of velocity of flow. 3. When the porosity ratio and the flow speed of the flume tank are fixed, the decrease of the velocity of flow which is passed the upper panel side is proportion to the increase of attack angle. 4. As a result of comparison between the underwater shape by simulation which is applying the reduction ratio of flow speed from the experiment using plane netting and that by model experiment, it was found out that the result of the simulation was very close to that of model gear within ${\pm}$ 5 % error range.

• Journal of Fisheries and Marine Sciences Education
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• v.11 no.2
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• pp.203-215
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• 1999

Floating debris was recorded from a training ship, Kaya, of Pukyong National University with about 12 knots speed at July 19~21, 1999 and July 24~26. The sampled area is the Yellow Sea (YS) connected from Cheju Is. of Korea to Qindao harbor of China, divided into 88 unit segments on survey routes. Debris fabrication materials were categorized with 6 items using the following; man-made or natural wood items, paper and cardboard, nylon netting and rope, styrofoams, vinyl and plastics, floating metal and glass containers. All identified items within a $120{\pm}20m$ wide band were recorded but ignored if beyond this boundary. The results of distribution of floating debris in the area are as follows: 1. The greatest quantities of marine debris discovered during the survey were $184pieces\;per\;km^2$ near Qindao harbor. The next polluted areas, Sohuksan islands, positioned in the eastern part of YS were scattered in about $40pieces/km^2$ or so. 2. Among items, woods, paper and cardboard, vinyl and plastics were found out near Qindao Coast of China. On the other hand, there were many styrofoams, nylon netting and rope near the area of Sohuksan islands in the eastern part of YS. 3. The distribution densities of western part of YS near Qindao are varied with largely range in items and quantities but those of the eastern part, near Sohuksan islands were nearly constant. 4. Styrofoams were composed of 63% among all debris in YS, next paper and cardboard 15%, and wood item, vinyl and plastics each 10%. Therefore, marine debris of YS is revealed that distribution characteristics and composition are very different in each area. These phenomena are concluded that they largely depend on the life styles in land and the utilities of the sea. And of items, styrofoams is dominated by the distribution pattern of YS. Furthermore, surveys are continuously being investigated, and from this it is hoped that a much wider coverage can be achieved, perhaps all sites of the YS and contributed to the finding sources, the stationary area and removal method of debris joined the flow patterns.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.19 no.2
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• pp.85-91
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• 1983

The behaviour of shrimp in response to the trap was much influenced by the type, size and the dimensions of entrance as well as physiological and ecological conditions. The entry and the escape behaviour of shrimp to the model trap were observed in accordance with netting materials, baits, type and slope of entrance, and gathering response were also investigated on the odour of bait extracts in the aquarium from June to August, 1983. Entering shrimp to the circular entrance was significantly more than to the triangular or the square; however, no differences were found in the entry behacior among netting materials i e., P. A, P. E. and cotton. According as the slope of entrance was increased its angle from 0$^{\circ}$ to 90$^{\circ}$, number of entering shrimp was decreased; however, number of escaping shrimp at 30$^{\circ}$or 60$^{\circ}$ with time was fewer than at 0$^{\circ}$ or 90$^{\circ}$. Gathering responses of shrimp on the odours were more sensitive to the flesh of mackerel or the shrimp than to the pickled anchovy, or the pettitioes, while no differences were found between another bait extracts, i e., the shrimp and the flesh of mackerel, the short-necked clam and the horse mackerel, the flesh and the viscera of mackerel.

• Bulletin of the Society of Naval Architects of Korea
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• v.8 no.1
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• pp.67-94
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• 1971

Korean fisheries industry holds 57,255 boats amounting to 269,079 tons in gross as of the end of 1967. The boats of the size under 30G.T., about sixty-two per cent of the total in tonnage, are utilized in coastal and their contribution to the total production of Korean fisheries industry is estimated at over seventy-five percent. Hull forms and construction method of them are partly in transition stage to the western tradition from the oriental tradition, which employs the chine-type straight-framed section, and tick and wide wooden planking fastened on naturally bent timber frames. And only about a half of them are mechanized. About fifty-seven per cent, 7,525 boats amounting to 91,751 gross tons, of the coastal and inshore fishing boats are those of the size ranging 5G.T. to 30G.T., which are engaged mostly in draft-and gill-netting, angling, longlining, anchovy seining, squid fishing and set-netting. The important fishing boats forming main structure of the inshore fishing fleets can be classified as 5G.T.-class multi-purpose boats, 10G.T.-class angling/longlining boats and 20G.T.-class drift-/gill-netters mostly utilized in the east-sea, 15G.T.-class anchovy seiner in the south-sea-sea, 20G.T.- and 28G.T.-class stow-netters in the west sea. Each of the three sea regions, east, south, and west, of Korean water has distinctly different characters from one another in topography, geology and sea aspects, and consequently in marine resources, fishing grounds and fishing tactics desired. Hence, the finishing boats in each sea region have also their own characters in hull form, structural features, deck design and equipments. In this report, analyzing the characteristics of the existing inshore fishing boats ranging 5G.T. to 30G.T. in size from view points of naval architecture and engineering, the author made an integrated investigation of their characteristics, covering size and principal dimensions, hull form, deck design, structural features and mechanization, in close connection with the natural circumstances of Korean water and local techno-socio-economic problems, and, finally, made some suggestions for the rational improvement or modernization of the inshore fishing boats. Further details of the characteristics of Korean inshore finishing boats are referred to the drawings of them compiled by the author and given in the reference[23] listed at the end of this report.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.94-101
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• 2015

The heat treatment machine based on immersion was developed to reduce temperature difference during netting process and appraised it performance compared current heat treatment machine using high pressure. It was also reviewed the optimum heat treatment procedures for PBSAT monofilament net in accordance with the immersion time and temperature. The procedure was based on physical measurement such as breaking load, elongation and angle of the mesh for PBSAT monofilament. The water temperature gap of the treatment machine based on immersion was less than $1^{\circ}C$. and the energy consumption was also increased in high temperature condition. It was identified that the optimum temperature was $75^{\circ}C$ and its optimum processing time was between 15 minutes and 20 minutes to get qualified physical properties.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.1
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• pp.20-31
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• 2010

In this research, the submersible fish cage was designed to avoid structural and biological damage during harsh sea conditions. The submersible cage system consists of netting, mooring ropes, a floating collar, floats, sinkers and anchors. Whole elements of the cage were modeled on the mass-spring model. The computer simulations were carried out to investigate the dynamic behavior of the cage and to calculate mooring line tension subjected to tidal currents and waves. As expected, the tension values in the mooring line of the submerged position are 36% less compared to that of the surface cage under the same loading conditions. As the wave was used in combination with the current velocity of 1m/s, the average tensile load for the submerged cage showed 85% of the value for the floating cage. The simulation results provide an improved understanding of the behaviors of the structure and valuable information on the optimized design of the cage system exposed to open ocean environmental factors.

• Journal of Plant Biotechnology
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• v.43 no.4
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• pp.444-449
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• 2016

Deep rooting, which enables plants to extract water from greater soil depths, is a critical strategy for improving plant survival under water-deficient conditions. However, as it is difficult to observe intact root systems belowground, several techniques have been developed to screen deep- and shallow-rooting phenotypes in rice. Here, we introduce a simple and convenient method for deep- and shallow-rooting phenotyping using a unique combination of sand, soil, and plastic mesh netting. Vandana, a drought-tolerant rice variety, and Dongjin, a Korean japonica rice variety, were used to analyze root phenotypes. No significant differences in root length were observed in rice grown under irrigated conditions regardless of net position, whereas roots were significantly longer, and ratio of deep root (RDR) values were significantly higher in Vandana rice grown under semi-drought conditions. In summary, this simple and useful method represents a low-cost means of phenotyping the roots of rice and other crops grown in various-sized pots and at multiple plant growth stages.

• Journal of Korean Society for Quality Management
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• v.47 no.4
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• pp.725-737
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• 2019

Purpose: We used a data analysis method to improve semiconductor manufacturing yield. We defined and optimized important factors and applied our findings to a real-world process. The semiconductor industry is very cost-competitive; our findings are useful. Methods: We collected data on 15 independent variables and one dependent variable (yield); we removed outliers and missing values. Using SPSS Modeler ver. 18.0, we analyzed the data both continuously and discretely and identified common factors. Results: We optimized two independent variables in terms of process conditions; yield improved. We used DS Leak software to model netting and Contact CD software to model meshes. DS Leak shows smaller the better characterisrics and Contact CD shows normal the best characteristics Conclusion: Various efforts have been made to improve semiconductor manufacturing yields, and many studies have created models or analyzed various characteristics. We not only defined important factors but also showed how to control processing to improve semiconductor yield.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.81-84
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• 2007

In this paper, fiber optic sound and vibration monitoring sensor which is latticed shape structure based on Sagnac interferometer is fabricated and tested in laboratory conditions. To detect external vibrations surface mounted fibers on the latticed steel wire fence with a dimension of 170cm by 180cm is used. To detect external sound frequency the tightened fiber optic itself wire netting fence with a dimension of 50cm by 50cm is used. Experiments for the detection of the excited vibration and sound signals were performed. A small vibrator induced external vibration signal and it is applied to the latticed structure in the range of 100Hz to several kHz. External sound signal applied to the fiber optic sensor net using non-directional sound speaker. The detected optical signals were compared and analyzed to the detected both accelerometer and microphone signals in the time and frequency domain. Based on the experimental results, distributed fiber optic sensor using Sagnac interferometer detected effectively external vibration and sound signal and had a good performance. This system can be expanded to the monitoring of a significant system and to the structural health monitoring system.

• Ocean and Polar Research
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• v.23 no.3
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• pp.305-310
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• 2001

This paper describes a floating fish reef technology for enhancement of fisheries productivity in the muddy areas. The floating fish reef was composed of main fish cage, anchor rope and concrete anchor blocks. Main fish cage was made up of 12 steel buoys measuring 0.37m in diameter and 1.5m long, polyethylene (PE) netting and circular steel rings. Each steel buoy had buoyancy of 110kgf. The size of main fish cage was 1.96 m in diameter and 3.75m in length. Monitoring on its durability was made for eight months after installation. The steel buoys fixed on main fish cage and nettings were observed to be kept safely. The wet weight of fouling organisms per unit area$(m^2)$ was 26.6kgf after eight months. Reduction in the cross-section of steel buoys and circular steel rings of main fish cage were not found. In addition, any cracks on the concrete anchor blocks were not observed.