• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.432-440
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• 2015

The hydro-acoustic technology has been widely used in not only South Korea but also many foreign countries for various scientific purposes. Unfortunately acoustic data especially collected from field surveys may contain noises caused by a variety of sources. Therefore, it is exceedingly important to eliminate noises when acoustic data are analyzed to derive quantitative results. This study introduced two methods for eliminating noises easily and effectively using post-processing software. Used acoustic data were collected on the Jinhae bay and Tongyeong coast of the South Sea in April 2015. The first method, that is the Wang's method, placed emphasis on 'erosion filter' to eliminate only data samples contaminated by noises. The second method (Yamandu's method) focused on the 'resample by number of pings' to remove pings contained noises. To substantiate the effectiveness of two methods, the mean Sv (Volume backscattering strength), mean height and depth of the fish schools detected were compared between before and after using the noise elimination methods. In the Wang's method the mean Sv was decreased from -52.4 dB to -52.9 dB, and in the Yamandu's method from -52.6 dB to -53.3 dB, indicating that noises were successfully eliminated. The mean height (1.5 m) and depth (19.0 m) were same between before and after using two methods showing that the shapes of fish schools were not changed.

• Proceedings of KOSOMES biannual meeting
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• 2006.05a
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• pp.185-193
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• 2006

This research reviews the change of fishery environment, the change of fishery production affected by agreement execution and the situation of agreement violation after the execution cf fisheries agreements between Korea and China and between Korea and Japan to understand the achievement of fishery management of EEZ after the fishery agreements. It will focus on EEZ fishing banks between Korea and China and between Korea and Japan.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.99-104
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• 2003

The maritime security risk has been recognized since the terrorists attacked the world trade center and the Pentagon In this paper, maritime security risk is analyzed on the basis if the data of crime in Korean sea We propose the countermeasures to prevent maritime security threats

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.13-18
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• 2005

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.53 no.2
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• pp.177-186
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• 2017

This study is intended to provide navigator with specific information necessary to assist in the avoidance of collision and in operation of ships to evaluate the maneuverability of research vessel Jera. Authors carried out full-scale sea trials for turning test, zig-zag test, and spiral test at actual sea-going condition, which were performed on starboard and port sides with 10-20 rudder angle at service speed of 10 knots. The turning circle was much different at both of the turning of port and starboard which was longer at the starboard than at the port. In the zig-zag test results, the port and starboard was $10^{\circ}$ the first and second overshoot angles were $6.0^{\circ}$, $5.8^{\circ}$ and $6.3^{\circ}$, $7.1^{\circ}$ respectively and the first overshoot angles were $16.4^{\circ}$, $17.6^{\circ}$ when using $20^{\circ}$. Her maneuverability index T and N can be easily determined by using an analogue computer with the data obtained from the zig-zag tests where K is a constant representing the turning ability and T is a constant representing her quick response. In the zig-zag tests under $10^{\circ}$ or $20^{\circ}$ at rudder angle, the value K is 0.149. 0.123 sec- and T is 11.853 and 6.193 sec and angular velocity is $0.937^{\circ}/sec$ and $1.636^{\circ}/sec$. In the spiral test, the loop width was unstable at $+0.51^{\circ}$ and $-1.19^{\circ}$ around the midship of rudder, but the tangent line at $0^{\circ}$ was close to vertical. From the sea trial results, we found that she did comply with the present criterion in the standards of maneuverability of IMO.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.48 no.4
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• pp.479-486
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• 2012

In order to obtain the fundamental data about the behavior of conger by underwater audible sound, this experiment was carried out to investigate the hearing ability of Conger eel Conger myriaster which was in the coast of Jeju Island by heartbeat conditioning method using pure tones coupled with a delayed electric shock. The audible range of conger eel extended from 50Hz to 300Hz with a peak sensitivity at 80Hz including less sensitivity over 200Hz. The mean auditory thresholds of conger eel at the frequencies of 50Hz, 80Hz, 100Hz, 200Hz and 300Hz were 105dB, 92dB, 96dB, 128dB and 140dB, respectively. The positive response of conger eel was not evident after the sound projection of over 200Hz. At the results, the sensitive frequency range of conger eel is narrow in spite of swim bladder. Auditory masking was determined for Conger eel by using masking stimuli with the spectrum level range of about 60~70dB (0dB re $1{\mu}Pa/\sqrt{Hz}$). According to white noise level, the auditory thresholds increased as compared with thresholds in a quiet background noise including critical ratio at 68dB of white noise from minimum 26dB to maximum 30dB at test frequencies of 80Hz and 100Hz. The noise spectrum level at the start of masking was distributed at the range of about 68dB within 80~100Hz.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.2
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• pp.130-140
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• 2022

Recently, wideband acoustic technology has been introduced and started to be used in fisheries acoustic surveys in various waters worldwide. Wideband acoustic data provides high vertical resolution, high signal-to-noise ratio and continuous frequency characteristics over a wide frequency range for species identification. In this study, the main characteristics of wideband acoustic systems were elaborated, and a general methodology for wideband acoustic data analysis was presented using data collected in frequency modulation mode for the first time in Republic of Korea. In particular, this study described the data recording method using the mission planner of the wideband autonomous acoustic system, wideband acoustic data signal processing, calibration and the wideband frequency response graph. Since wideband acoustic systems are currently installed on many training and research vessels, it is expected that the results of this study can be used as basic knowledge for fisheries acoustic research using the state-of-the-art system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.4
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• pp.309-316
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• 2008

This article discusses the legal character and admissible scope of inspection and police questioning of a vessel with force in comparison with the systems of the US and Japan. The author focuses on the factual differences between vessels and cars which justifies the varying standard. A ship at sea may easily slip away and destroy evidence while authorities attempt to get a warrant. Thus, a warrantless boarding and safety inspection could be validated because of the exigent circumstances of the sea.

• Proceedings of KOSOMES biannual meeting
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• 2003.05a
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• pp.89-97
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• 2003

To improve the educational system of Korea Maritime Police Agency(KMPA), the authors investigate and evaluate the present course and curricula in details comparing with the systems of USCG and JCG. As a result, it is suggested that KMPA find the diverse route to recruit good-quality officers, develop the future-oriented system, coordinate the course and curricula to meet the role and mission of KMPA. Besides, KMPA build the own training facility and train special instructors.

• Journal of the Korean Society of Marine Environment & Safety
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• v.7 no.2
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• pp.89-103
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• 2001

Korea Maritime Police Agency(KMPA) has been pressed by some environmental factors. The changes in the international maritime legal system, such as the entry into force of the UNCLOS in 1994 and the promulgation of the Korea 200-mile EEZ, have radically expanded the mission of the KMPA. In addition, there is, among other nations, no such large size maritime agency, equivalent to the KMPA, except in the cases of USA, Canada, and Japan. And what is more, critics outside the KMPA, including some other government agencies and stakeholders may propose to dismantle the KMPA. In this paper, the author highlights the internal and external issues facing KMPL, and he urges KMPA to change the organizational culture for maintaining its identity and characteristics by adopting the Total Quality Management. And he tries to assess the adoption of TQM on KMPA, by using the Feasibility Assessment Technique.