• Journal of the Korean Institute of Navigation
• /
• v.24 no.1
• /
• pp.13-22
• /
• 2000

The collisions at sea among marine casualties are not reduced as the tonnage and speed of ship's increase as well as the traffic quantity increase at sea, in spite of the improvement of nautical equipment, enforcement of crew's education and training as well as improvement of quality standard according to the implementation of ISM code. The measures to prevent the collisions at sea are simple, and are composed of six stage.: The first stage is that the officer on duty detect the target from his eye or radar information. The second stage is determining the type and kind of target-ship. The third stage is target tracking; calculation of target speed, course, CPA and TCPA from radar information or visual check. The fourth stage is determination of vessel in danger after calculation of third stage. The fifth stage is the judgement of situation if own ship is stand-on or give way vessel according to the 1972 COLREG. The last stage is to carry out proper action according to 1972 COLREG, under the circumstances. But by the case, the situations are so different under the different external conditions; for example, natural/navigational conditions, crew's human factors, ship's particular, rule or regulation, management system on board, the condition of watch keeping. Therefore the reasons and casualties are so complicated. This study aims to investigate the collision casualty at sea which needs to clarity all these causal factors of afore-mentioned, and to analyze the causes of problems so as to utilize them to establish the measures of preventing marine accidents. This study, described the concepts of causal factors into three groups; environmental factor, and company/on board management system and navigator's act. Also described how to investigate and analyzes the casual factors. Even though it was described in this paper how to detect the causal factors and reasons of collisions, and how to analyze the inter-relation of each causal factors, it is necessary to do further study how to analyze between the liability of concerned parties and the casual factors involved.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.4
• /
• pp.499-506
• /
• 2022

For autonomous ships to be commercialized and be able to navigate in coastal water, they must be able to detect maritime obstacles. One of the most common obstacles seen in coastal area are the farm buoys. In this study, a maritime object detection system was developed that detects buoys using the YOLO algorithm and visualizes the distance and bearing between buoys and the ship through geometric interpretation of camera images. After training the maritime object detection model with 1,224 pictures of buoys, the precision of the model was 89.0%, the recall was 95.0%, and the F1-score was 92.0%. Camera calibration had been conducted to calculate the distance and bearing of an object away from the camera using the obtained image coordinates and Experiment A and B were designed to verify the performance of the maritime object detection system. As a result of verifying the performance of the maritime object detection system, it can be seen that the maritime object detection system is superior to radar in its short-distance detection capability, so that it can be used as a navigational aid along with the radar.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.29 no.7
• /
• pp.887-892
• /
• 2023

Vessel traffic service(VTS) centers are equipped with RADAR, AIS(Automatic Identification System), weather sensors, and VHF(Very High Frequency). VTS operators use this equipment to observe the movement of ships operating in the VTS area and provide information. The VTS data generated by these various devices is highly valuable for analyzing maritime traffic situation. However, owing to a lack of compatibility between system manufacturers or policy issues, they are often not systematically managed. Therefore, we developed the VTS Bigdata Platform that could efficiently collect, store, and manage control data collected by the VTS, and this paper describes its design and implementation. A microservice architecture was applied to secure operational stability that was one of the important issues in the development of the platform. In addition, the performance of the platform could be improved by dualizing the storage for real-time navigation information. The implemented system was tested using real maritime data to check its performance, identify additional improvements, and consider its feasibility in a real VTS environment.

• 한국HCI학회:학술대회논문집
• /
• 2009.02a
• /
• pp.650-653
• /
• 2009

Decrease in crew performance is frequently cited as a major causal factor in maritime accidents. Although considerable researches on working hours undertaken by seafarers have been conducted through interviews and record analyses, experimental studies on the effects of factors, such as high workload, shift patterns, stress, sleep deprivation, and disturbance on the cognitive performance of mariners have been limited. Other safety-critical transport industries, such as aviation and rail, have developed fatigue management tools to help managements in the work patterns of their operators. Such tools for mariners would assist shipboard crews, marine pilots, and shore managers for planning and improving work schedules. The overall aim of this paper is to determine a fatigue factor that can be applied to human performance data as a part of a software program that calculates total cognitive performance. This program enables us to establish the levels of cognitive performance in a group of marine pilots in order to test a decision-making task based on radar information. This paper addresses one of the factors that may contribute to the determination of various fatigue factors: the effects of different work patterns on the cognitive performance of a marine pilot.

• Journal of the Society of Naval Architects of Korea
• /
• v.43 no.3 s.147
• /
• pp.384-391
• /
• 2006

RCS effects of long-crested wave surfaces to marine targets are numerically analyzed using a 4-path model and a direct analysis method, developed based on physical optics and a combined method of physical optics/geometric optics, respectively. Reflectivity of long-crested wave surfaces is described with 'Fresnel reflection coefficients' The MPM(modified Pierson-Moskowitz) ocean spectrum is adopted to simulate long-crested waves in the direct analysis method. A numerical analysis of a benchmark model assures the validity of both methods. The direct analysis method is applied to the RCS calculation of electromagnetically large marine targets, which are vertically oriented or slanted to the long crested wave surfaces randomly generated with various significant wave heights. The long-crested wave surface much highly increases the RCS of the marine target, but those effects are decreased as the significant wave height grows up. At low elevation angle, the vertical model has entirely high RCS comparing slanted model, and the RCS of vertical flat plate is the highest on the calm sea surface, while those of slanted flat plates are the lowest on the calm sea surface. The RCS of marine targets on continuously-varying sea surface is more coherent at lower elevation angles, as well.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2010.04a
• /
• pp.473-480
• /
• 2010

A key objective is to meet the requirements for safe marine transport and protection of the marine environment by providing a comprehensive mix of Aids to Navigation commensurate with the amount of traffic and the degree of risk. The development of e-Navigation is driven by the compelling need to equip the master of a vessel and those ashore responsible for the safety of shipping with modem, proven tools to improve the reliability of marine navigation and communications. Although position fixing using GNSS is widely used, radar and visual AtoNs continue to be needed to provide safe, secure and environmentally clean navigation. The paper considers the role, evolution and future provision of traditional aids to navigation in an e-Navigation environment from both a technical and mariner perspective.

• Journal of Advanced Marine Engineering and Technology
• /
• v.35 no.4
• /
• pp.512-518
• /
• 2011

The marine equipment industry in Korea has been growing along with shipbuilding industry since early 1980s. Major shipbuilding might be predicted to shift to China in the near future. Moreover, new paradigm of e-navigation is about to get geared in the real world, which was specifically noted by IMO (International Maritime Organization). In order to catch up with rapid changes in the environments, the industry sector should move fast, the public sector should setup proper measures, and the academic sector should spur the research and development of new technologies. In this paper, international marin equipment markets and standardization trends are presented along with several representative R&D activities.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.21 no.4
• /
• pp.421-427
• /
• 2015

This study aims at reviewing first the cases of marine accidents of small fishing vessels and vessels towing and being towed and, the problems concerning such lights and shapes that could be misunderstood for those in concerned Rules, or that could impair their distinctive characteristics or obstruct to keep a proper look-out. And then I wish to make a suggestion of the necessity of amending the National Laws which stipulate the rules for the ship's lights and shapes as follows; Firstly, by amending the "Standard of Construction and Equipment for the Less Than 10 Gross Tonnage of Small Fishing Vessels" small fishing vessel must be equipped with the lights and shapes that are the same as those of "vessel engaged in fishing" prescribed by Rule 26 of the "COLREG 1972" and Rule 84 of the "Maritime Safety Law Act". Secondly, "Standard of Fishing Vessels Equipment" which stipulate the rules concerning the exception of the running lights and radar reflector for the small fishing vessels must be amended to meet the requirement of Rule 20 of the "Maritime Safety Act". Thirdly, the definition of "Length of the tow" which prescribed by Rule 2 of the "Maritime Safety Act" must be amended to meet the Rule 24 of the "COLREG 1972". And also I wish to adhere to the importance of displaying the adequate vessel lights and shapes by every mariner for preventing marine accidents.

• Journal of the Korean Society of Safety
• /
• v.35 no.3
• /
• pp.79-85
• /
• 2020

Ahn-heung Proving Ground(APG) of Agency for Defense Development(ADD) is the only weapon test site which has been performing firing tests for many kinds of missile, artillery and ammunition. APG has been performing the firing tests of so many times every year. The tests related to missiles, artillery and ammunitions cover 80% among the quantity of annual test events. The target area of many kinds of missile, artillery and ammunition is on the sea. Therefore, APG has its marine firing ranges which were approved by the ministry of Defense. Both weapons and ships can run into each other on the sea. APG has to monitor and detect the positions of the ships in the specific dangerous zone on the sea. The positions of the ships are detected by Scanter 2001 radar and GPS100 detection radar. Evading the time period when the ships appear very often on the sea may be a good solution to keep the maritime safety. And evading the place where the ships appear very often on the sea may be a good solution as well. This paper is to analyze the ships' distribution characteristics of marine firing range, which are to raise the efficiency of many kinds firing tests which have been performed in APG of ADD. Ship distribution data from February 2014 to December 2016 were used in this paper. Ship distribution was analyzed with monthly data, seasonal data and etc. The number of the ships in approved sea area is higher in the morning than in the afternoon, and in fall than other seasons, and from August to November, and below 0.5 m in the hight of wave. Using the these conditions, we can raise the test efficiency of many kinds firing tests and guarantee maritime safety. The number of the ships in approved sea area is entirely unrelated to visibility of the sea. The time period when the number of the ships are high on the sea is morning. The season when the number of the ships are comparatively high on the sea is fall. APG of ADD could raise the efficiency of the firing tests and improve the maritime safety, using the analysis results of the characteristics on the ship distribution.

• Structural Engineering and Mechanics
• /
• v.30 no.6
• /
• pp.679-698
• /
• 2008

On marine vessels, delicate instruments such as navigation radars are normally mounted on ship masts. However the vibrations at the top of mast where the radar is mounted often cause serious deterioration in radar-tracking resolution. The most serious problem is caused by the rotational vibrations at the top of mast that may be due to wind loading, inertial loading from ship rolling and base excitations induced by the running propeller. This paper presents a method of semi-active vibration control using magneto-rheological (MR) dampers to reduce the rotational vibration of the mast. In the study, the classical optimal control algorithm, the independent modal space control algorithm and the double input - single output fuzzy control algorithm are employed for the vibration control. As the phenomenological model of an MR damper is highly nonlinear, which is difficult to analyse, a back- propagation neural network is trained to emulate the inverse dynamic characteristics of the MR damper in the analysis. The trained neural network gives the required voltage for each MR damper based on the displacement, velocity and control force of the MR damper quickly. Numerical simulations show that the proposed control methods can effectively suppress the rotational vibrations at the top of mast.