• Journal of Ocean Engineering and Technology
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• v.21 no.3 s.76
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• pp.40-45
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• 2007

This study was performed to investigate the effect of various propeller tunnel shapes on the propulsion performance of a fishing boat. The propeller tunnel reduces the problem resulting from the open propeller accidentally catching the waste net and cable on the sea, as well as increasing the cruising speed. For 3 different tunnel geometries, the model test is conducted in the circular water channel, and the potential based panel method was applied to analyze the hydrodynamic characteristics of propeller. Also, both results are compared with each other to represent the difference between results of the model scale test and the potential theory. It is expected that these results could be referenced in the design of the propeller tunnel in consideration of the hydrodynamic interaction between the propeller and the tunnel.

• The Journal of Fisheries Business Administration
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• v.39 no.1
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• pp.115-132
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• 2008

This study raises the question about why do many international fisheries organizations or regional fisheries agreements come into existence, sustain, and develop prior to the internationally recognized institution such as United Nations Convention on the Law of the Sea(UNCLOS). In oder to solve the problem, I will investigate the characteristics of fisheries as renewable resources and propose the collusion model where it is based on the cost-benefit analysis. Especially, if once a fooall large number of fishing is implemented, they are immediately depleted. Consequently they are extinct and no longer exploitable. Thus each interest nations or participants will be better off if they are cooperative and will be worse off if they are competitive or noncooperative in a resource management. Therefore, many of the internationally recognized fisheries institutions and agreements have been made and developed in these days.

• Journal of the Korean Institute of Navigation
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• v.19 no.3
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• pp.11-19
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• 1995

When an automatic course keeping is introduced, as is quite popular in modern navigation, the closed-loop control system consists of autopilot device, power unit, steering gear, ship dynamics, and magnetic or gyrocompass. We derive mathematical models of each element of the automatic steering system. We provide a method of theoretical analysis on the propulsive energy loss related to automatic steering of ships in the open seas, taking account of the on-off(non-linear) characteristics of power unit. Also we paid attention to non-linear element installed in autopilot device, which is normally called weather adjuster. Next we make numerical calculation of the effects of autopilot control constants on the propulsive energy loss for two kinds of ship, a fishing boat and an ore carrier. Realistic sea and wind disturbances are employed in the calculation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.605-615
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• 2017

A multi-resonant broadband acoustic transducer with six Tonpilz elements operating at different resonant frequencies in a transducer assembly was fabricated, tested, and analyzed. A compensated transducer, modified by adding series inductance to the developed multi-resonant broadband transducer, was shown to provide improved bandwidth performance with a relatively more uniform frequency response compared with the uncompensated transducer. By controlling the series inductance, flat frequency response characteristics at two frequency bands were obtained over the range 38-52 kHz with 1.1 mH inductance and 50-60 kHz with 0.4 mH inductance. These results suggest that the operating frequency of the developed multi-resonant broadband transducer in a chirp echo sounder can be shifted to a different frequency band that is optimized according to the environment for more effective echo surveys of fishing grounds.

• Journal of Species Research
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• v.5 no.3
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• pp.348-350
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• 2016

An asteroid specimen was collected from Jumunjin, Gangwon-do in the East Sea, Korea at a depth of 50 m using fishing nets on 26 May 2013. It was identified as Pteraster militaris (O.F. $M{\ddot{u}ller$, 1776) belonging to the family Pterasteridae of the order Velatida based on morphological characteristics. This species is usually distributed in the cold boreal zone around northern Pacific and Atlantic, and is distinctly distinguished from P. tesselatus which was reported in Korean fauna: body form, length ratio of arm to disc and surface of dorsal membrane.

• Journal of the Korean Institute of Navigation
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• v.25 no.4
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• pp.407-415
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• 2001

In the present study, irregular disturbances to ship dynamics is proposed, where irregular disturbances implying irregular wave and the fluctuating component of wind for the evaluation of automatic steering system of ship in following seas. Prediction method based on the principle of linear superposition. Irregular wave disturbances in following seas is calculated by frequency variation method. The mathematical model of each element of an automatic steering system is derived, which takes account of a few non-linear mechanisms. PD(Proportional-Derivative) controller and low-pass filter with a weather adjustment are adopted to modelling the characteristics of an autopilot. Performance index is introduced from the viewpoint of energy saving, which derived from the concept of energy loss on ship propulsion. Finally, the present methods are applied to two typical types of ship ; an ore carrier and a fishing boat. The various effects of control constants of autopilot on propulsive energy loss are investigated

• Animal Systematics, Evolution and Diversity
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• v.27 no.2
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• pp.180-182
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• 2011

Sea stars were collected with fishing nets between depths of 40-150 m from the Gangwon-do coastal region, East Sea. Specimens were identified as Evasterias echinosoma Fisher, 1926 belonging to the family Asteriidae, which is new to the Korean fauna. This species was characterized by strong external spines and a general size of more than 200 mm, thus the largest sea star identified in Korea to date. Its morphological characteristics are described here with photos. Thirty two asteroid species including E. echinosoma have been reported from the East Sea of Korea.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.96-100
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• 2000

Recently ocean environmental pollution becomes very serious, so each governmental organization slove this problem. As part of the policy, KRISO has investigated distribution condition at ocean waste. Acc\ulcorner we found that combustble waste consists of ropes, fishing nets, and tires. These are, however, highly polyme\ulcorner existing incicerators have many problems to treat these. In this study we want to pyrolyze highly polymerized \ulcorner data for a design of fule production system without second pollution. Through the thermogravimetic experiment characteristics of pyrolysis and obtained some preliminary results.

• Journal of the Korean housing association
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• v.8 no.3
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• pp.177-185
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• 1997

This study analyzed the leisure activity and using behavior of neighbourhood facilities for the aged. For this purpose, this study is to compare the preferred characteristics of the leisure and neighbourhood facilities according to housing type and region (urban/rural), The data of this study was collected by questionaire methods from 225 elderlies. The statistical analysis methods used in this study are frequency, percentage, chisquare test and anova, The results are following, l)The elderlies show differences in daily life and social relationship by housing type. 2)In leisure activities, the apartment elderlies preferred to sport, tour, climbing and fishing rather than the detached housing elderdies. 3)Apartment have more neighbour facilities than detached housing. But using frequency of facilities is low. Especially, most of the elderlies think that medical facilities is very important.

• Composites Research
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• v.12 no.5
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• pp.80-86
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• 1999

Mechanical characteristics of composite laminates and cylindrical shell using scrim of glass scrim are evaluated in this paper. Composite laminates and cylindrical shells are made by inserting carbon scrim or glass scrim between layers. The mechanical properties are routinely characterized by ASTM stands. Experimental results show that the mechanical properties of UD prepreg in the transverse direction are highly improved by inderting scrims between layers.