• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.57-62
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• 2004

A mariner feels the ship-handling difficulty when the vessel onboard passes through breakwater. Until now, there is no a layout design of breakwater to take into account the ship-handling difficulty for the mariner. 11Us paper reproduced this situation which ship-handling is difficult by using marine traffic flow simulation, and it applied to Environmental Stress Model as the assessment model which is a quantitative model for evaluating the difficulty of ship-handling arising from restriction in maneuvering water areas and arising from traffic congestion The results are as follows. (1) The layout change of breakwater has little influence for reduction of ship-handling difficulty in the areas of vessel traffic volume. (2) In the situation of same breakwater width, difference of ship speed has an effect on decrease of ship-handling difficulty. (3) Expansion of breakwater width decreases ship-handling difficulty quantitatively.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.4
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• pp.397-402
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• 2015

This study is to compare variation indexes by monthly, weekly and hourly using AIS data, which was collected for 365 days from January 1st to December 31st, 2013 at Mokpo Port and then, computed the maximum standard error by observation days. The comparison of monthly variation indexes showed that the monthly variation indexes for September and February were 1.11 and 0.84, respectively, in turn revealing that the maritime traffic in September was about 32.1 % larger than February. Also, the daily variation indexes for Tuesday and Sunday were 1.05 and 0.92, respectively, in turn revealing that the maritime traffic in Tuesday was about 14.1 % larger than Sunday. When the maritime traffic investigation is executed for at least 1 week in consideration of the daily variation index, it is possible to reduce the maximum standard error rate to be within 21 %. Therefore, if the maritime traffic investigation is made in the month and week with low maritime traffic, each variation index should be applied to reflect the actual maritime traffic.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.5
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• pp.501-506
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• 2015

This study seeks to analyze ships traffic characteristics according to water time in order to provide the necessary data for efficient traffic management development. To analyze maritime traffic volume according to water time, 1 year amount of solar calendar data were converted into lunar calendar, and then applied the traditional water time system of West Sea by using AIS(Automatic Identification System) observation data gathered in Mokpo port for a year of 2013. As a result, it was found herein that the number of outbound ships was larger on the $2^{nd}-3^{nd}$ water times than the $7^{th}$ water times by 23-24 %. And the number of inbound ships was higher on the $12^{th}-13^{th}$ water times than the $9^{th}$ water time by 29-33 %. The hourly variation index of inbound and outbound ships according to time, in particular, was found to change in the form of sine function model. This study is expected to serve as a necessary basic material for development of maritime traffic management according to water time.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.3
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• pp.339-345
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• 2018

Sunrise and sunset times differ depending on location and date. Previous studies conveniently but monotonously applied day and night times set up. This research defined the daytime and nighttime while considering the time of twilight according to the date and the location of ship collision accidents. Classifying the frequency of ship collision accidents with this standard, we conducted a chi-squared test for the difference between daytime and nighttime. The frequencies of ship collision accidents according to daytime and nighttime was compared by season, month, and time, and all of them showed statistically significant differences. The highest number of daytime ship collisions was 11.6 %, in June, and nighttime collisions peaked at 13.7 %, in December. The most frequent hour for daytime ship collisions was 0700h-0800h, at 10.2 %, and nighttime collisions peaked between 0400h-0500h, at 16.9 %. It is clear that the criteria used in previous studies cited was applied without any theoretical basis and likely only for the convenience of the researchers. It was found that results depend on what criteria are applied to the same research data. This study shows that statistical analyses of marine accidents, traffic volume, and congestion density should be carried out quantitatively while considering daytime and nighttime hours for each particular location and date.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.2
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• pp.164-170
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• 2013

With the introduction of increasingly large-sized ships, the conditions of main domestic port facilities remain the same as in the past. So, there is high probability that marine traffic congestion can occur at the certain ship's routes. The standard ship's length used to assess the marine traffic congestion of domestic trade port is 70 meters. It has been in use for the last 30 years, so, its usefulness is highly recommended for review. This study deeply analyzes the tendency of ship's dimensional changes according to recent enlargement of ship's size by utilizing the particulars of 60,000 ships saved in domestic Port-MIS database and suggests the standard ship's length by figuring out the correlation between length of ship and gross tonnage. In addition, the basis of statistical data on the ship's tonnage in domestic trade over the last five years suggests the standard ship's length by deriving the reference point of cumulative incidences that occupy more than over 50 %, except for small vessels. It is necessary to consider the characteristic of each domestic trade port before the actual application of suggested standard ship's length.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.1
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• pp.74-80
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• 2021

When a berth is built close to a fairway, a moored vessel will be affected by the ship waves generated by navigating vessels. In this study, a portable measurement system was developed to measure the roll motion of an actual vessel, and the results were compared with simulation results. The simulation results showed that the roll motion satisfies the loading safety criteria. However, the actual results of the vessel, did not satisfy the criteria in some cases. In this study, 18 cases that did not satisfy the loading safety criteria were analyzed. Among these cases, three cases were affected by a different time zone of the remaining 15 cases, 11 cases (73.3%) were observed to be consistent with arrival times of passenger ships of more than 10,000GT sailing between in Mokpo and Jeju. The results of this study can be used to reflect marine traffic characteristics in the assessment of loading safety, which can increase the reliability of results of the loading safety assessment of ships.

• Proceedings of KOSOMES biannual meeting
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• 2018.06a
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• pp.49-49
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• 2018

• Proceedings of KOSOMES biannual meeting
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• 2017.04a
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• pp.19-19
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• 2017

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.253-256
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• 2005

The use of satellite remote sensing in maritime safety and security can aid in the detection of illegal fishing activities and provide more efficient use of limited aircraft or patrol craft resources. In the area of vessel traffic monitoring for commercial vessels, Vessel Traffic Service (VTS) which use the ground-based radar system have some difficulties in detecting moving ships due to the limited detection range. A virtual vessel traffic control system is introduced to contribute to prevent a marine accident such as collision and stranding from happening. Existing VTS has its limit. The virtual vessel traffic control system consists of both data acquisition by satellite remote sensing and a simulation of traffic environment stress based on the satellite data, remotely sensed data. And it could be used to provide timely and detailed information about the marine safety, including the location, speed and direction of ships, and help us operate vessels safely and efficiently. If environmental stress values are simulated for the ship information derived from satellite data, proper actions can be taken to prevent accidents. Since optical sensor has a high spatial resolution, JERS satellite data are used to track ships and extract their information. We present an algorithm of automatic identification of ship size and velocity. This paper lastly introduce the field testing results of ship detection by RADARSAT SAR imagery, and propose a new approach for a Vessel Monitoring System(VMS), including VTS, and SAR combination service.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.7
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• pp.828-835
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• 2023

Vessel traffic service operators (VTSOs) need to quickly and accurately analyze the maritime traffic situation in the vessel traffic service (VTS) area and provide information to the vessels. However, if traf ic increases rapidly, the workload of VTSOs increases, and they may not be able to provide adequate information. Therefore, it is essential to develop VTSO support technologies that can reduce their workload and provide consistent information. In this paper, we propose a model for automatically detecting abnormal vessels in the VTS area. The proposed model consists of a positional model and a contextual model and is specifically optimized for the traffic characteristics of the target area. The implemented model was tested by using real-world data collected at a test center (Daesan Port VTS). Our experiments confirmed that the model could automatically detect various abnormal situations, and the results were validated through expert evaluation.