• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.210-211
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• 2023

To reduce maritime accidents and improve safety for domestic ships, the government has developed and is operating the Korean e-Navigation Service. The ship collision and grounding monitoring service and the route planning service were developed based on the experience of captains and navigators who navigated large ships. However, in Korea, small ships account for a large portion of the users of these services, so there are various difficulties and additional requirements for applying services based on large ships to small ships. To improve this, a data science-based algorithm model using maritime digital traffic information is being developed for small ships, and it is important to evaluate the performance of the developed model and compare its accuracy with existing services. In this study, we propose a performance evaluation method for the developed algorithm model and study how to compare and evaluate its accuracy with existing e-navigation services.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.204-205
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• 2023

This study studied a prediction model for sending collision alarms for small fishing boats based on semi-supervised learning(SSL). The supervised learning (SL) method requires a large number of labeled data, but the labeling process takes a lot of resources and time. This study used service data collected through a data pipeline linked to 'intelligent maritime traffic information service' and data collected from real-sea experiment. The model accuracy was improved as a result of learning not only real-sea experiment data with labeling determined based on actual user satisfaction but also service data without label determined together.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.393-403
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• 2022

Various studies suggest that the initial operating form of UAM, which is being presented as a solution to the urban traffic problem, will be similar to VTOL aircraft among current aircraft. In a form similar to determining the direction of the runway where fixed-wing aircraft take off and land, the vertiport where take-off and landing of VTOL aircraft takes place determines the flight direction of departure and arrival in consideration of the direction of the wind. Unlike areas where airports are generally built, in the case of downtown areas, it is expected that the characteristics of wind may continuously change depending on the environment of changing terrain or obstacles such as the construction of new buildings. In this study, long-term actual observation data for reviewing the take-off and landing directions at the city center where the location of the vertiport is expected are compared using a wind speed map, and the characteristics of the ground wind and the possibility of change in the direction of the predominant wind depending on the observation period and observation location confirmed.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.419-429
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• 2023

The pinnacle of rapidly changing and advancing maritime transportation technology is expected to be the Maritime Autonomous Surface Ship (MASS). The implementation of various services within the MASS is likely to be feasible through the ship-centric network known as the S2X communication system. However, existing communication systems face issues such as service traffic saturation and failure to meet demanded functionalities, necessitating the proactive introduction of additional communication technologies. In this study, the concept of S2X communication for the MASS was redefined, deriving required functionalities and ultimately selecting frequencies suitable for utilization. Candidate frequency groups suitable for the derived communication requirements were identified, and communication frequencies prioritized for the initial application were chosen through expert consensus. It is anticipated that through further research, including experimentation to validate these frequencies, they could be utilized in implementing services for autonomous ship navigation in the future.

• The KIPS Transactions:PartC
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• v.10C no.3
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• pp.367-376
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• 2003

This study deals with the DCMST (Delay constrained Capacitated Minimum Spanning Tree) problem applied in the topological design of local networks or finding several communication paths from root node. While the traditional CMST problem has only the traffic capacity constraint served by a port of root node, the DCMST problem has the additional mean delay constraint of network. The DCMST problem consists of finding a set of spanning trees to link end-nodes to the root node satisfying the traffic requirements at end-nodes and the required mean delay of network. The objective function of problem is to minimize the total link cost. This paper presents two-phased heuristic algorithm, which consists of node exchange, and node shift algorithm based on the trade-off criterions, and mean delay algorithm. Actual computational experience and performance analysis show that the proposed algorithm can produce better solution than the existing algorithm for the CMST problem to consider the mean delay constraint in terms of cost.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.3
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• pp.248-256
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• 2013

Part 2 of the Questionnaire Survey on Marine Safety and VTS in the Philippine Coastal Waters presents the alternatives to risk reduction, modifying the VTS, the qualification and competency of a VTS operator and effectiveness of the services and assistance rendered by VTS. This study finds that majority of respondents chose "Improved education and training of mariners" as the best alternative to risk reduction and the "Strict enforcement of ship safety regulations" as the best alternative based on the respondents' ranks last served onboard and areas of familiarity. In modifying the VTS, the areas with VTS chose to "Improve or upgrade" and for those without, is to "Implement" the system. The best VTS system is the "Port and Approaches" type and the PCG is selected to operate, maintain and supervise the system. As a VTS operator, the necessity of shipboard experience is considered "Essential" and the experiences include "Ship-handling and Communication", and "Management level" experiences. The effectiveness of the assistance and services rendered by VTS are considered "Very Important". Based on these findings, this study recommends improvement of education and training of mariners and users of the waterways including the training of VTS operators manning the VTS centers, strict enforcement of ship safety regulations along the busy and main ports of the country and installation of VTS system with the most appropriate type with the supervision of PCG.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.1
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• pp.515-524
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• 2014

In this paper, The investment prioritization model was investigated for keeping the service level of mooring facilities more than the target level of management with a limited budget in the right time. Network level prioritization criteria of the national scale was developed to take into criteria index and quantitative evaluation, management authority's opinion. Delphi method was conducted maintenance exports of mooring facilities over twice for verifying the validity and adequacy. In order to improve the objectivity of criteria, the criteria for evaluating the utilization of port facilities is presented form yearly facility traffic/facility's length, the result of the analysis of facility traffic data. The investment prioritization criteria of mooring facilities is expected to be utilized for more efficient and national budget distribution applied to the maintenance budget plan of nationwide.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.111-117
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• 2017

The arrival time of rescue ships is very important in the event of distress. This paper presents the development of experimental data to calculate the arrival time of rescue ships. The ship's traffic probability distribution was used. Mokpo Port was selected as the area of study, and AIS data for a 1 year period were used. For the ship's traffic probability distribution, a gateline was established. The lateral range distribution was calculated and fitted to the normal distribution and two Gaussian mixture distributions (GMD2), and each parameter was extracted. After the locations of ${\mu}$, ${\mu}{\pm}1{\sigma}$ of the normal distribution and ${\mu}_1$ of the two Gaussian mixture distribution(GMD2) were set as waypoints, the location and probability were determined. A scenario was established in relation to each type of parameter. Thus, the arrival time can be calculated.

• Journal of the Korean Institute of Navigation
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• v.12 no.1
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• pp.71-84
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• 1988

For traffic proceeding in random directions on a plane surface the frequency of collision, if no avoiding action in taken ,is approximately proportional to the square of the traffic density and directly proportional to the size and speed of the ship, Avoiding is normally taken and the rte of collisions is therefore also governed by additional factors such as the visibility, the effectiveness of the collisionavoidance rules, the competence of personnel or watchkeeping attitude, the maneuverability of the ship and the efficiency of radar and other equipments. From the viewpoint of watchkeeper who is responsible for maneuvering, watchkeeping attitude such as lookout and action to avoid collision is the most controllable factor among those mentioned above. In practice, according to the investigation of the institution of marine courts, about 50% co collisions occurred is caused by disorbedience to steering and sailing rules of international regulations for preventing collision at sea including lookout. So we classify the process of collisions with first sight of another ship , assessment of risk of collisions and action to avoid collisions and make a factural survey about lookout and action to avoid collisions from the point on "time" and " distance", namely relationship among ship's size, speed, first sight time of another ship, action to avoid collisions ,and distance from sight of another ship to collision occurred. According to the results of the actual survey , we come to conclude that most of collisions occurred are due to improper lookout and ineffective action to avoid collision which means time lag from first sight of another ship to time of action taken to avoid collision is relatively long. is relatively long.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.2
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• pp.119-125
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• 2009

Recently the construction of bridges crossing navigable waterways is being promoted aiming at expanding social infrastructure and optimizing the overland routes through private investment. The construction, however, tends to focus on more the commercial requirements than the marine safety and efficient port management that it has a big risk not only to fail in ensuring the safety of ship traffic, but also to muse some severe conflicts between the parties concerned. These problems result from the lacking of standards about the design guidelines and discussing process considering the marine traffic safety when designing bridges. This research attempts to show the problems mused by bridge construction and suggest the standard discussing process through the survey and process analysis on Kwangyang Bridge and Incheon Bridge.