• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.46 no.4
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• pp.430-440
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• 2010

To investigate the catches of jack mackerel fishery, a series of fishing experiments was conducted in the high seas of the southeastern Pacific Ocean ($30^{\circ}S-38^{\circ}S,\;82^{\circ}W-95^{\circ}W$) during the period of 9 August to 18 December, 2003 by commercial fishing vessel and research vessel. The number of 205 tows fishing was carried out in the southeastern Pacific Ocean. The total catch was 1,988 ton and CPUE was 2.4 ton/hour. CPUE showed high values in the frontal zone during the survey. Main target species caught from the experimental fishing were the jack mackerel, Trachurus murphyi (98.1%) and chub mackerel, Scomber japonicus (1.9%) as bycatch. Body length of the jack mackerel was different between female and male. The high mean catch per unit effort of jack mackerel was showed when the fishing ground of jack mackerel fishery was over the $110^{\circ}W$ in the southeastern Pacific Ocean. But the fluctuation of the catch per unit effort in the western part of fishing ground was not matched with those year. Reliable physical and oceanographical information will be useful for the efficiency of fishing activity. According to the result of monthly movement of center of fishing ground, the fishing activity of jack mackerel fishery was performed northward in the southeastern Pacific Ocean as time passes.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.54 no.2
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• pp.97-106
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• 2018

The objective of this study was to estimate physical properties and fishing performances of net twine with improved PBS copolymer resin (Bio-new), the existing PBS/PBAT blending resin (Bio-old) and commercial Nylon (Nylon). The tensile strength of Bio-new monofilament was equal to Bio-old and the elongation of Bio-new was about 6 % higher than that of Bio-old in wet condition. The physical properties tests were carried out to estimate breaking load and stiffness in dry and wet conditions, respectively. In the results, the breaking load of Nylon netting was the highest whereas the elongation of Bio-new was 1.4 times higher than that of Nylon netting in wet condition. The breaking load of Bio-old netting was about 9.2 % higher than that of Bio-new netting. However, the elongation of the Bio-new netting was about 3% higher than that of Bio-old. The stiffness of the Bio-new compared to Bio-old was improved about 34 % in dry condition and about 32 % in wet condition. The filed experiments of the fishing performance were conducted with three kinds of drift nets with different netting materials in the coastal sea of Jeju. The each experimental drift net made of different materials showed the similar fishing performance. Bio-old drift net yielded less catches of small sized yellow croaker than other drift nets. The netting materials affected the fishing performance and length distribution of catches in the drift nets.

• Journal of Ocean Engineering and Technology
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• v.21 no.3 s.76
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• pp.46-51
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• 2007

A multi-purpose environmental monitoring system has been developed as a commercially available standard using the technique of hetero-core spliced fiber optic sensors, for the purposes of monitoring large-scale structures and preserving natural environments. The monitoring system has been tested and evaluated in a possible outdoor condition, in view of the full-scale operation at actual sites to be monitored. Additionally, the developed system in this work conveniently provides us with various options of sensor modules intended for monitoring such physical quantities as displacement, distortion, pressure, binary states, and liquid adhesion. Two channels of optical fiber line were monitored in each channel, three displacement sensor modules were connected in series, in order to examine the performance to a pseudo-cracking experiment in the outdoor situation and to clarify temperature influences an the system, in terms of the coupling of optical connectors and the OTDR stability. The results from the pseudo-cracking experiment agreed with the actual cracks, by means of calculation, based an the detected displacement values and their geometrical arrangement of the used sensor modules. The temperature change, ranging from 10 to $20^{\circ}C$ resulting from the 10-days free running operation, was found to influence the system stability of ${\pm}10{\mu}m$, primarily due to the coupling instability of the used optical connectors. It was found that fusion splicing, rather than the use of connectors, reduced the fluctuation dawn to ${\pm}2{\mu}m$. The specification and performance of various option modules have been demonstrated to show the capability of inspecting various physical quantities by use of the single system, which would be suitable for multi-purpose environmental monitoring.

• Journal of Korea Multimedia Society
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• v.15 no.4
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• pp.560-568
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• 2012

As for the implementation technology of virtual space, the experience method becomes multifunctional and it recognizes movement, sound, temperature and pressure and is expanding to the studies on the interaction possible intelligent interaction technology field between contents and users. The virtual reality technology is being studied to apply the 3D graphic technology and physical phenomena to virtual space to increase the sense of reality and use hardware devices to the virtual environment to increase immersive experience. The production of interactive contents about the virtual underwater environment needs bidirectional interface technology to connect hardware devices and ocean contents in order to increase the sense of a user to increase the sense of immersion. In this study, it tried to express the virtual underwater environment with the sense of actuality and reality from the analysis of the environmental factors according to changes in depth of water and from the application of the normalized underwater physical laws. Also it was to develop sensory contents having to experience the skin scuba without directly entering the water by connecting a sensory simulator about the skin scuba with the virtual underwater environment.

• Proceedings of the KSRS Conference
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• v.2
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• pp.529-532
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• 2006

The oceanic currents in the South China Sea (SCS) are strongly influenced by monsoon winds. A review on the SCS currents has indicated that previous studies have pointed out an anticyclonic circulation in the area between the southern Vietnam coast and the Spratly Islands. However, its detail is not understood because of less information of in situ observations. The physical-biological interaction is quite new research area, which has been established and promoted by means of the ocean color remote sensing. Temporal/spatial variability of the phytoplankton activities are well captured by ocean color (OC) -derived Chlorophyll-a images. Combining the OC-Chl-a and the other high-resolution satellite data (e.g., SST images), the biological aspects of oceanographic variation is well described. The blooming phenomena in the area between the southern Vietnam coast and the Spratly islands are further investigated. Change in the wind-system related to the El Nino generates upwelling/SST-cooling in the sea south of the Spratly Islands through the air-sea-land interaction was studied. The seasonal upwelling is also associated with the harmful algal bloom (HAB) off two side of Indochina Peninsula have investigated. The seasonal variation of SCS phytoplankton blooming and related oceanic conditions in Vietnam coast was observed. Ocean color satellite data has effective contribute to study the oceanic condition and phytoplankton blooming in South China Sea.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.10
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• pp.1333-1339
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• 2014

As the demand for petroleum resources increases, and oilfields on lands and in shallow-sea become exhausted, the areas for oil production are expanding to the deep sea and therefore technologies for flow assurance are coming into the highlight. In low temperature environment such as the deep sea, wax is accumulated and prevents stable oil production. Therefore, the development of flow assurance technologies is required. Wax is precipitated in crystalline form when the oil temperature decreases below the wax appearance temperature; it then accumulates on the inner walls of pipelines causing blockages. In particular, in subsea pipelines, which have a large surface contact area with the surrounding seawater, wax deposition problems are frequent. The internal tubular coating can effectively reduce wax deposition without pausing oil production when the coating is appropriately designed. This study carried out wax deposition tests on a number of internal tubular coatings under single flow conditions. The results were analyzed for the effects that the physical properties of the coatings had on wax deposition.

• International Journal of Naval Architecture and Ocean Engineering
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• v.5 no.3
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• pp.468-477
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• 2013

An automatic pipe routing system is proposed and implemented. Generally, the pipe routing design as a part of the shipbuilding process requires a considerable number of man hours due to the complexity which comes from physical and operational constraints and the crucial influence on outfitting construction productivity. Therefore, the automation of pipe routing design operations and processes has always been one of the most important goals for improvements in shipbuilding design. The proposed system is applied to a pipe routing design in the engine room space of a commercial ship. The effectiveness of this system is verified as a reasonable form of support for pipe routing design jobs. The automatic routing result of this system can serve as a good basis model in the initial stages of pipe routing design, allowing the designer to reduce their design lead time significantly. As a result, the design productivity overall can be improved with this automatic pipe routing system.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.10a
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• pp.167-173
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• 2002

For moving cargo between the North Pacific region and Northern European ports, the Northern Sea Route, along Russia's coastline, is 35-60% shorter than the traditionally used routes through the Suez and Panama Canals. In addition to its shorter distance, there exists and extensive ports and shipping infrastructure, and the potential for developing new markets in Russia and other northern countries including Korea and Japan. These incentives attracted considerable attention from the international shipping and shipbuilding industries and have formed a cooperative international research program, called as the International Northern Sea Route Programme (INSROP). This paper is a general compilation of the historical usage, recent trade developments, the physical environment, and the practical considerations that may shape future operational mode of shipping in the NSR based on results from INSROP reports. This study focuses mainly on an operation of commercial icebreaking vessels that may be utilized along the NSR.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.165-173
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• 2005

Field observations have been conducted to investigate the physical environment around oyster farms in Gamak Bay. Tidal waves near the two channels at the northeast and south of the bay had almost the same amplitudes and phases. Water temperature responded sensibly to the tides, rising at high water and falling at low water, except for the northwest region. The currents more regularly varied in accordance with a tidal period as long as they are at the faster-flowing region. A considerable flow has been found near the seabed of the northwest of the bay, normally known to be a stagnant area, and also the flow was opposite to the surface flow. Average moving speeds and directions of the flow at each station coincided well with patterns of the residual currents computed by Lee ef al. [2004], except for the northwest region. The discrepancy for the northwest region is not clear but it may have resulted from the facts that the computed flow pattern represents only the case of spring tide and in addition, a northwesterly wind prevailed all the observation time.

• Journal of Navigation and Port Research
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• v.32 no.6
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• pp.515-519
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• 2008

Using the analytical framework designed by Lester, this study analyzes self-governing capacity of ocean environmental management of Busan Metropolitan City pursuing establishment of ocean capital as one of the impending goals. Following Lester's methodology, this study analyzes the levels of two critical variables: will of chief executives and physical base. It was found that mayor of Busan Metrocity and high-level public managers concerned showed somewhat low levels of will, considering Busan is the top-ranked ocean city in South Korea. Comparison of number qf public servants and size of budget for ocean environmental management with seven other metropolitan cities in Korea also revealed that Busan Metropolitan City maintained a relatively low level of physical base. In conclusion, the level of self-governing capacity of ocean environmental management of Busan Metropolitan city is classified into the type of regressives or the type of delayers.