• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.4
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• pp.403-408
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• 2015

A text-based communication system has been developed with a communication function on AIS and display and input function on ECDIS as a way to complement voice communication. It features no linguistic error and is not affected by VHF restrictions on use and noise. The text communication system is designed to use messages for clear intentions and further improves convenience of users by using various UI through software. It works without additional hardware installation and modification and can transmit a sentence by selecting only via Message Banner Interface without keyboard input and furthermore has a advantage to enhance processing speed through its own message coding and decoding. It is determined as the most useful alternative to reduce language limitations and recognition errors of the user and solve the problem of various voice communications on VHF. In addition, it will help to prevent collisions between ships with decrease in VHF use, accurate communication and request of cooperation based on text at heavy traffic areas.

• Journal of Navigation and Port Research
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• v.29 no.3 s.99
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• pp.203-213
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• 2005

The International Maritime Organization(IMO) which is responsible for measures to improve the safety and security of international shipping and to prevent marine pollution from ships is a specialized agency of the United Nations. It is involved in legal matters, including liability and compensation issues and the facilitation of international maritime traffic as well. But the ROK has not been actively coping with the environment of the shipping industry because of the absence of the organization or researching bodies that specialized in the field related to IMO. Therefore this paper investigates the maritime administration system of the major countries such as the USA, japan and the UK. And particularly by conducting IMO research and responding system, this study gathers relevant materials from those countries for the comparison and analysis with the purpose of providing the ROK with the assistance in forming the responding measures in the shipping and shipbuilding industries.

• Journal of the Korean Institute of Navigation
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• v.21 no.2
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• pp.47-58
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• 1997

The purpose of this study is to find out the impacts of VTS on the marine safety and users' opinion on the VTS which have been being operated in the port of Pohang for the last 3 years and is to suggest a guideline to the successful operation of VTS in the future. This study is based upon the questionnaire survey and the respondents include 236 masters/mates of merchant vessels who have visited the port of Pohang and 6 pilots who have been working in the port. From the questionnaire results, this study notes the following conclusions related to the VTS operations. (1) A few of the respondents (mainly foreigners) do not understand the entering procedure of the port and the fundamental concept of VTS. Accordingly, the more active VTS services have to be provided for the mariners. (2) It was found that themost dangerous factors in tehvicinity of the port were the floating materials, fishing nets, andillegal fishing activities inthe fairway. Therefore, the proper surveillance, stricter enforcement of Acts and the instructive education for the fishermen are required to avoid the risks. (3) A majority of the respondents agreed the VTS has contributed to the safety of vessel traffic, and they pointed out ' the assiatances in reduced visibililty conditions' is the most important task of VTS. The amount of 75.6% of the respondents answered that they have experienced the assistance from VTS more than 1 time since the system was established in the port of Pohang . Also 44.2% of the respondents considered they were able to avoid marine casualties such as collision, ramming or agrounding with the VTS assistances. (4) 49.2% of the respondents preferred the passive information services , while, 38.8% of them preferred the positive control advices in the case of encountering any potential risks. VTS iperators have to consider seriously when they provide the positive control advices of ship's course and speed. (5) A majority of the respondents confirmed that the prot and its approaches is suitable for the VTS coverge . To extend the service areas of the VTS and to improve radar detecting ability, the use of radar transponders are seen as the ideal method. (6) A minority of the respondents pointed out 'the improper orders or recommendatinos caused by the poor decision making' firstly, ' the language problem(sea-speaking in English)' secondly, as the deficiency of personal qualification. It seems, therefore, theat the personal efforts of the operators and systematic training programmes for them are necessary to solve the problems.

• Journal of the Korean GEO-environmental Society
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• v.21 no.9
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• pp.25-32
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• 2020

The underground utilities installed under the ground is an important civil engineering structure, such as water supply and sewerage pipes, underground power lines, various communication lines, and city gas pipes. Such underground utilities can be exposed to risk due to external factors such as concentrated rainfall and vehicle load, and it is important to select and construct an appropriate backfill material. Currently, a method mainly used is to fill the soil around the underground utilities and compact it. But it is difficult to compact the lower part of the buried pipe and the compaction efficiency decreases, reducing the stability of the underground utilities and causing various damages. In addition, there are disadvantages such as a decrease in ground strength due to disturbance of the ground, a complicated construction process, and construction costs increase because the construction period becomes longer, and civil complaints due to traffic restrictions. One way to solve this problem is to use a liquid filler. The liquid filler has advantages such as self-leveling ability, self-compaction, fluidity, artificial strength control, and low strength that can be re-excavated for maintenance. In this study, uniaxial compression strength test and fluidity test were performed to characterize the mixed soil using marine clay, stabilizer, and in-situ soil as backfill material. A freezing-thawing test was performed to understand the strength characteristics of the liquid filler by freezing, and in order to examine the effect of the filling materials on the corrosion of the underground pipe, an electrical resistivity test and a pH test were performed.

• Journal of the Korean Institute of Navigation
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• v.24 no.1
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• pp.1-12
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• 2000

The ships over the certain navigation area or her length are required to carry charts under the relevant laws. Charts are indispensible to the ships and fishing vessel, because their crew should know the water depth and location of obstacle in order to avoid danger in the navigation and fishing area. But it was found that many ships do not carry proper charts onboard according to the research marine accidents files of marine accident inquiry agency, and questionnaire survey. Consequently, many ships run aground on the coast and port. This study examined the present status of the coastal ship and the fishing vessels, and explained some problems in the aspect of the covering area, the place, the number of the selling agent and adjoining chart, as well as the geographical and traffic density, the crew on board the ship's characteristics, and so on. In this study we propose the way to solve the problem. firstly, the category of the fishing vessel which should carry the chart on bard under the related laws are required to be lowered to 10 gross tons. Besides a ship inspector should examine if the charts covering the area where to navigate even when the temporary inspection is done are carried on board property. Secondly, the inspection body or the controlling office of ship's entry and departure should check throughly whether the ships concerned carry the chart on board. Thirdly the fishing vessels should used the fishing charts, and the body concerned should train the offices about how to use chart, especiany the difference between Tokyo datum and WGS-84 datum. Fourthly the customized chart such as an atlas like a map, a calenda-type chart, a small chart, as a coated chart needs to be publish for the safety of small ship and fishing vessel. Fifthly, it is advisable to draw a recommended course in the route where the coastal navigate mainly and in the narrow channel, The adjoining area should be improved, as well as the qualify of the chart paper. Sixthly, publication of additional new chart in the southern part of East Sea, the eastern part of South Sea, the western part of South Sea and middle part of Yellow Sea near Incheon port should be thought over. Seventhly, the number of chart selling agent should be increased for the sake of purchaser in proportion to the number of port, and small correction of charts in selling agent must be carried out completely.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.6
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• pp.822-831
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• 2021

Although programs have been developed to evaluate the risk of dragging anchors, it is practically difficult for VTS(vessel traffic service) operators to calculate and evaluate these risks by obtaining input factors from anchored ships. Therefore, in this study, the gross tonnage (GT) that could be easily obtained from the ship by the VTS operators was set as an independent variable, and linear and nonlinear regression analyses were performed using the input factors as the dependent variables. From comparing the fit of the polynomial model (linear) and power series model (nonlinear), the power series model was evaluated to be more suitable for all input factors in the case of container ships and bulk carriers. However, in the case of tanker ships, the power supply model was suitable for the LBP(length between perpendiculars), width, and draft, and the polynomial model was evaluated to be more suitable for the front wind pressure area, weight of the anchor, equipment number, and height of the hawse pipe from the bottom of the ship. In addition, all other dependent variables, except for the front wind pressure area factor of the tanker ship, showed high degrees of fit with a coefficient of determination (R-squared value) of 0.7 or more. Therefore, among the input factors of the dragging anchor risk assessment program, all factors except the external force, seabed quality, water depth, and amount of anchor chain let out are automatically applied by the regression analysis model formula when only the GT of the ship is provided.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.4
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• pp.483-491
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• 2021

The identification of regional collision risks in water areas is significant for the safety of navigation. This paper introduces a new method of collision risk assessment that incorporates a clustering method based on the distance factor - hierarchical clustering - and uses real-time data in case of several surrounding vessels, group methodology and preliminary assessment to classify vessels and evaluate the basis of collision risk evaluation (called HCAAP processing). The vessels are clustered using the hierarchical program to obtain clusters of encounter vessels and are combined with the preliminary assessment to filter relatively safe vessels. Subsequently, the distance at the closest point of approach (DCPA) and time to the closest point of approach (TCPA) between encounter vessels within each cluster are calculated to obtain the relation and comparison with the collision risk index (CRI). The mathematical relationship of CRI for each cluster of encounter vessels with DCPA and TCPA is constructed using a negative exponential function. Operators can easily evaluate the safety of all vessels navigating in the defined area using the calculated CRI. Therefore, this framework can improve the safety and security of vessel traffic transportation and reduce the loss of life and property. To illustrate the effectiveness of the framework proposed, an experimental case study was conducted within the coastal waters of Mokpo, Korea. The results demonstrated that the framework was effective and efficient in detecting and ranking collision risk indexes between encounter vessels within each cluster, which allowed an automatic risk prioritization of encounter vessels for further investigation by operators.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.2
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• pp.297-306
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• 2022

AtoN is an acronym for aids to navigation that indicate the position or direction of navigable areas and obstructions. AtoN should be arranged in consideration of unfamiliar navigator's convenience when it is indicated as the limits of navigable areas. Several narrow channels exist on the SW coast of Korea owing to the geographical effect, and the lateral or cardinal marks by the IALA maritime buoyage system are arranged along the narrow channels. This is an actual case study that analyzed the AtoN's role for safety navigation after changes in the maritime traffic environment owing to aquarfarm's development on narrow channels in the Korean SW coast. The analysis results of 5 narrow channels indicated that certain marks did not function properly as lateral or cardinal marks owing to the aquarfarm's location on navigable areas. Therefore, the following were suggested to improve AtoN on narrow channels: changing the position of marks, installing aquafarm's marks, and expressing the aquafarm's position on the nautical chart.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.341-349
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• 2023

Gamcheon Port, which is one of three major harbors in the Port of Busan, is being operated to load, discharge and transport a wide range of cargoes, including general cargo, fisheries, steel products, cement, etc,. The harbor, designated as a compulsory pilotage area, provides pilotage services in compliance with relevant laws and regulations for arrival and departure of vessels in the Gamcheon Port area. Some academic research on the marine traffic environment in Gamcheon Port has been conducted. However, the pilotage environment and hazards to pilotage safety in the port have yet to be studied. Therefore, in this research, the pilotage environment and hazards to pilotage safety were identified, and it was confirmed that there are hazards to pilotage safety, such as vessels installed poor facilities including damaged pilot boarding arrangements, vessels blocking pilot's view by her structures and fishing nets, vessels unable to communicate in English, vessels not following VTS's order. The hazards to pilotage safety were also stratified, and the importance of the hazards was verified in accordance with a survey based on Analytic Hierachy P rocess(AHP) for Busan Harbor pilots, and safety measures to secure pilotage safety were examined to secure the safety of vessels calling Gamcheon Port.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.367-375
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• 2023

This study developed a new distance metric for vessel trajectories, applicable to marine traffic control services in the Korean coastal waters. The proposed metric is designed through the weighted summation of the traditional Hausdorff distance, which measures the similarity between spatiotemporal data and incorporates the differences in the average Speed Over Ground (SOG) and the variance in Course Over Ground (COG) between two trajectories. To validate the effectiveness of this new metric, a comparative analysis was conducted using the actual Automatic Identification System (AIS) trajectory data, in conjunction with an agglomerative clustering algorithm. Data visualizations were used to confirm that the results of trajectory clustering, with the new metric, reflect geographical distances and the distribution of vessel behavioral characteristics more accurately, than conventional metrics such as the Hausdorff distance and Dynamic Time Warping distance. Quantitatively, based on the Davies-Bouldin index, the clustering results were found to be superior or comparable and demonstrated exceptional efficiency in computational distance calculation.