• Journal of the Korean Institute of Navigation
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• v.15 no.3
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• pp.1-11
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• 1991

As increasing needs of marine transportation , world merchant fleet and ship's size were enlarged and it caused frequent disasters in human lives and natural environment. By the reason of the above, they started to establish the Vessel Traffic System (VTS) at the European coast in 1960' and most of advanced contries established and managed it to prevent the sea traffic accidents in these days. The concept of traffic control at sea can be divided into three types. First, the initial gathering of informations about ship's identity and movement etc.. Second, monitoring of the traffic flow and amendment of instructions. Third , organization and direction of ships by allocating routes and speeds. Where the goal of traffic control is safety of traffics and developing effectiveness of navigation channel, if traffic volume is less tan channel capacity then the above first or second level of control would be sufficient but if it is bigger than that , more positive policy of control should be adopted as same as third type of the above. In this paper where the strategy of VTS is focused on the control of traffic density to be spread equality, as possible , all over the navigation channels and also improvement of effectiveness , it suggests algorithm to assign the vessels to the channels with balanced traffic density , and other algorithms using D.P. to sequence the vessels assigned to one channel in optimum order which decreases the mean waiting time in sense of channel effectiveness with numerical examples.

• Ocean and Polar Research
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• v.44 no.2
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• pp.161-177
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• 2022

Microalgae can attach to the surface of ships and then spread to various areas by means of ship transport. The introduction of invasive species through ships is recognized as a marine problem worldwide. Identification of attached microalgae is necessary to investigate such movement between countries through ships. In the present study, through analytical methods we reviewed research data to identify the taxa of domestic attached microalgae and assess the ecological impacts of such microalgae. A total of 87 genera and 153 species (143 species of diatoms, 10 species of cyanobacteria, and 4 genera of dinoflagellates) were identified as native attached microalgae in Korea, and diatoms accounted for 93% of the total. Most of these attached microalgae were identified through research on natural substrates such as seaweeds and bedrock, and some were also identified through experiments using artificial adherent plates. To date, there is no information on microalgae attached to international ships and introduced into Korea. Molecular genetic analysis and systematic management through on-site sampling of international ships, microscopic analysis, and meta-barcoding are necessary to assess the inflow and spread path of hull-attached marine alien species and evaluate the risk they pose to the domestic ecosystem.

• Journal of the Korea Society for Simulation
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• v.19 no.4
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• pp.1-9
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• 2010

In this paper, advanced evacuation analysis simulation on a passenger ship is performed. Velocity based model has been implemented and used to calculate the movement of the individual passengers under the evacuation situation. The age and gender of each passenger are considered as the factors of walking speed. Flocking algorithm is applied for the passenger's group behavior. Penalty walking velocity is introduced to avoid collision between the passengers and obstacles, and to prevent the position overlap among passengers. Application of flocking algorithm and penalty walking velocity to evacuation simulation is verified through implementation of the 11 test problems in IMO (International Maritime Organization) MSC (Maritime Safety Committee) Circulation 1238.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.38 no.3
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• pp.249-255
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• 2002

This paper describes on the extraction of ship's real-time movement information using a combination full-function ARPA radar and ECS system that displays radar images and an electronic chart together on a single PC screen. The radar target extractor(RTX) board, developed by Marine Electronics Corporation of Korea, receives radar video, trigger, antenna bearing pulse and heading pulse signals from a radar unit and processes these signals to extract target information. The target data extracted from each pulse repetition interval in DSPs of RTX that installed in 16 bit ISA slot of a IBM PC compatible computer is formatted into a series of radar target messages. These messages are then transmitted to the host PC and displayed on a single screen. The position data of target in range and azimuth direction are stored and used for determining the center of the distributed target by arithmetic averaging after the detection of the target end. In this system, the electronic chart or radar screens can be displayed separately or simulaneously and in radar mode all information of radar targets can be recorded and replayed In spite of a PC based radar system, all essential information required for safe and efficient navigation of ship can be provided.

• The korean journal of orthodontics
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• v.23 no.1 s.40
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• pp.123-136
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• 1993

The purpose of this report is to present the successful improvement of occlusal relationship and facial esthetics in class II division 1 malocclusion with severe labioversion of upper anterior teeth and severe overjet, and in class II malocclusion with infraversion of bilateral maxillary canines by MEAW mechanics, which enables us to get effective distal on mass movement of maxillary dentition, with upper second molar extraction. After treatment, there were natural contact points at canine and premolar regions, normal occlusal relation-ship and treatment results, satisfied the gnathologic concept, in this 2 cases. Compared with the routine treatment with premolar extraction, the treatment time and patients' discomfort were reduced. And the MEAW mechanics, which enables us to get effective distal on mass movement of maxillary dentition, resulted in reduction of the treatment time and getting the good treatment results. Consequently, the majot concerns in orthodontic treatment are appropriate diagnosis and treatment plan, so, the application of second molar extraction with appropriate case analysis and diagnosis is very helpful to orthodontic treatment.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.277-282
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• 2006

The purpose in having a control surface on a ship is to control the motion of the ship. The control surface may be composed entirely of a single movable surface or of a combination of fixed and movable portion A control surface has one sole function to perform in meeting its purpose, and that is to develop a control force in consequence of its orientation and movement relative to the water. The forces and moments generated as a result of this rotation and angle of attack then determine the maneuvering characteristics of the ship. In this paper the study of flapped rudder's 2-dimensional section was accomplished. Model tests had been carried out with different angles of attack of a main foil and flap's deflection angles to predict the performance of the flapped rudder and the 2 frame particle tracking method had been used to obtain the velocity distribution in the flow field $Re=2.8\times10^4$ had been used during the whole experiments and measured results had been compared with each other.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.11a
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• pp.139-145
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• 2002

The flow zone through propeller jets are used in evaluating the environmental and constructional effects of navigation on the waterway. It relies on the characteristics of ships and water depth. A numerical model using the momentum theory of the propeller and Shield's diagram was developed in a restricted waterway. Equations for discharge are presented based on thrust coefficients and propeller speed and are the most accurate means of defining discharge. Approximate methods for discharge are developed based on applied ship's power. Equations for discharge are as a function of applied power, propeller diameter, and ship speed. Water depth of the waterway and draft of the shop are also necessary for the calculation of the grain size of the initial motion. The velocity distribution of discharge from the propeller was simulated by the Gaussian normal distribution function. The shear velocity and shear stress were from the Sternberg's formula. Case studies to show the influence of significant factors on sediment movement induced by the ship's propeller at the channel bottom are presented.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.5
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• pp.389-399
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• 2024

Currently, shipyards are using ship block supports to hold various pre-erection (PE) blocks during ship construction work. The height adjustment method of the ship block support is performed by workers hammering and driving the wedge part, which requires repetitive high-load work. Accordingly, there are concerns about musculoskeletal diseases and safety accidents. To prevent safety accidents and improve work efficiency, this study developed a block support height adjustment device using a hydraulic cylinder. It was designed considering the ease of movement of the block support height adjustment device and the ease of adjusting the height of the block support by workers within the shipyard. Numerical analysis was conducted to confirm the critical points of the structural members of the designed block support height adjustment device and to verify the safety of the stress-based structure. As a result of the analysis, it was confirmed that the stress occurring at the critical point of the structural member was lower than the design allowable stress, making it structurally safe. Afterwards, the block support height adjustment device was redesigned for lightweight, and after verification of structural safety through numerical analysis, a prototype was manufactured and performance evaluation was conducted.

• Journal of Navigation and Port Research
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• v.47 no.6
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• pp.350-357
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• 2023

Marine accidents frequently occur due to the unreasonable operation of ships excluded from ship departure control during marine special weather warnings within smooth water areas. Coastal wave buoys installed in smooth water areas are major reference indicators for ship departure control and can be seen as being directly connected to the safety of ships navigating smooth water areas and the coast. In this study, the location appropriateness of currently operating coastal wave buoys and additional installation in the smooth water areas were assessed by analyzing coastal marine accidents over the past 30 years (1991-2020), the main wind direction and wind speed of each major trading port, and the GICOMS ship track data in 2018. The study results showed that an additional coastal wave buoy should be installed at each of the major trading ports(Inchon Port, Pohang Port, Ulsan Port, and Busan Port) and that the location of the coastal wave buoy needs to be moved in the case of Busan Port. Based on various data analysis in this study, the suggestion for an additional installation and movement of the coastal wave buoy presented in this study is expected to contribute to improving the reliability of ship departure control and resolving safety blind spots.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.7424-7429
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• 2014

GPS (Global Positioning System) is currently used widely in the ground section, such as surveying, mapping, geodesy, geophysics, the aviation section, such as aerial navigation and aerial photography, the sea section, including ship navigation and bathymetry, and space section, such as the satellite orbit and Earth's orbit. On the other hand, its use is limited due to the professional knowledge and expense to process the data for precise analysis. As a result, a web-based data processing solution for precise point positioning using GPS data was developed by c# for non-specialized people to process easily. In addition, the crustal movement speed of Korea after an earthquake was calculated to be an average of 30mm/year for each CORS, suggesting that it is possible to monitor crustal movement.