• Journal of Navigation and Port Research
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• v.27 no.2
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• pp.111-119
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• 2003

In order to improve navigational safety of ships, an ocean wave prediction model of high precision within a short time, dealing with multi-directional random waves from the information of the sea surface winds encountered at the planned ship's course, was introduced for construction of ocean wave forecasting system on the ship. In this paper, we investigated a sea disaster occurred by a stormy weather in the past. We analyzed the sea surface wind first and then carried out ocean wave hindercasting simulations according to the routes the sunken vessel. From the result of this study, we concluded that the sea disaster was caused by rapidly developed iou pressure system Okhotsk Sea and the predicted values by the third generation wave prediction model(WAM) was agreed well with the observed significant wave height, wave period, and directional wave spectrum. It gives a good applicability for construction of a practical on-board calculation system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.3
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• pp.219-225
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• 2008

Since July 2006, marine traffic safety management system have been enforced to support the vessels transiting across the coastal area and the vessels coming in and out of ports in southwestern coastal area where heavy traffic density and marine casualties occurred frequently. The marine traffic volume for the marine traffic environmental assessment was measured by the information from RADAR and AIS system in the area. The distributions of marine casualties were analyzed in the main routes and traffic separation schemes during the last five years and the navigational dangerous elements were investigated with the influence of natural environment, the distribution of fisheries and survey questionnaire. Marine accidents of merchant ships have a tendency to decrease gradually but in case of fishing boats, the rate of marine accidents have a contrary results in this area during the last five years. The dangerous elements on navigation appeared to be the dense force from June to August, fisheries activities and the vessels which not follow the compulsory watch on VHF-band radio communication equipments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2003.05a
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• pp.147-156
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• 2003

In order to improve navigational safety of ships, on ocean wave prediction model of high precision within a short time, dealing with multi-directional random waves from the information of the sea surface winds encountered at the planned ship's course, was introduced for construction of ocean wave forecasting system on the ship. In this paper, we investigated a sea disaster occurred by a stormy weather in the past. We analyzed the sea surface winds first and then carried out ocean wave hindercasting simulations according to the routes of the sunken vessel. From the result of this study, we concluded that the sea disaster was caused by rapidly developed low pressure system in Okhotsk Sea and the predicted values by the third generation wave prediction model(WAM) was agreed well with the observed significant wave height, was period, and directional wave spectrum. It gives a good applicability for construction of a practical on-board calculation system.

• Journal of Navigation and Port Research
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• v.33 no.1
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• pp.43-50
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• 2009

Recently, many maritime accidents have been increased and the collisions due to human error are given a great deal of proportions out of them We develop the Real-time Collision Risk Monitoring System (CRMS) for the navigational officers to cope with the emergency situation promptly and thus to reduce the probability of casualty. In this study, the risk of collision and grounding is evaluated by two kinds of method. The first method is based on Fuzzy algorithm, which evaluates the risk of collision between traffic ships. The second method is based on Environmental Stress (ES) Model, where the total risk of collision and grounding is evaluated by the environmental stress felt by human. The developed real-time CRMS has been installed to the ship handling simulator system and its capabilities have been tested through simulator experiments.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.10a
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• pp.144-145
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• 2010

VTM is regarded as a core element in e-Navigation under developing by IMO. IMO's e-Navigation aims for VTM which could provide more navigational information for ships and provide more active VTS services for safe and efficient marine traffic environment. To be successful for VTM under e-Navigation, VTS operator's experience and ability for carrying out VTM tasks are essential. In this study, Decision-making support system for VTS operators are designed conceptually which support VTS operators' VTM tasks by providing informations on traffic risk, and predicted behaviour of ships. This paper describes a designed system with design concept, main functions, main elements and necessary technologies to be developed.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.4
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• pp.288-294
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• 2014

Understanding a ship's present position has been one of the most important tasks during a ship's voyage, in both ancient and modern times. Particularly, a ship's dead reckoning (DR) has been used for predicting traffic situations and collision avoidance actions. However, the current system that uses the traditional method of calculating DR employs the received position and speed data only. Therefore, it is not applicable for predicting navigation within the harbor limits, owing to the frequent changes in the ship's course and speed in this region. In this study, planned routes were applied for improving the reliability of the proposed system and predicting the traffic patterns in advance. The proposed method of determining the dead reckoning position (DRP) uses not only the ships' received data but also the navigational patterns and tracking data in harbor limits. The Mercator sailing formulas were used for calculating the ships' DRPs and planned routes. The data on the traffic patterns were collected from the automatic identification system and analyzed using MATLAB. Two randomly chosen ships were analyzed for simulating their tracks and comparing the DR method during the timeframes of the ships' movement. The proposed method of calculating DR, combined with the information on planned routes and DRPs, is expected to contribute towards improving the decision-making abilities of operators.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1353-1358
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• 2021

IoT (Internet of Things) emerges from various technologies such as communications, micro processors and embedded system and so on. The IoT has also been used to UAV (Unmanned Aerial Vehicle) system. In manned aircraft, a pilot and co-pilot should control FCS (Flight Control System) with FBW(Fly By Wire) system for flight operation. In contrast, the flight operation in UAV system is remotely and fully managed by GCS (Ground Control System) almost in real time. To make it possible the communication channel should be necessary between the UAV and the GCS. There are many protocols between two systems. Amongst them, MAVLink (Macro Air Vehicle Link) protocol is representatively used due to its open architecture. MAVLink does not define any securities itself, which results in high vulnerability from external attacks. This paper proposes the method to enhance data security in GCS network by applying cryptographic methods to the MAVLink messages in order to support safe UAV operations.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2006.11a
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• pp.39-44
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• 2006

Ship's collision avoidance is a skill that masters of merchant marine vessels have acquired through years of experience and that makes them feel at ease to guide their ship out from danger quickly compared to inexperienced officers. Case based reasoning(CBR) uses the same technique in solving tasks that needs reference from variety of situations. CBR can render decision-making easier by retrieving past solutions from situations that are similar to the one at hand and make necessary adjustments in order to adapt them. In this paper, we propose to utilize the advantages of CBR in a support system for ship's collision avoidance while using fuzzy algorithm for its retrieval of similar navigational situations, stored in the casebase, thus avoiding the cumbersome tasks of creating a new solution each time a new situation is encountered. There will be two levels within the Fuzzy-CBR. The first level will identify the dangerous ships and index the new case. The second level will retrieve cases from casebase and adapt the solution to solve for the output. While CBR's accuracy depends on the efficient retrieval of possible solutions to be adapted from stored cases, fuzzy algorithm will improve the effectiveness of solving the similarity to a new case at hand.

• Journal of the Korea Society for Simulation
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• v.18 no.4
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• pp.9-20
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• 2009

Navigation system providing route-guidance and traffic information is one of the most widely used driver-support system these days. Most of the navigation system is based on the 2D map paradigm so the information is ed and encoded from the real world. As a result it imposes a cognitive burden to the driver to interpret and translate the ed information to real world information. As a new concept of navigation system, augmented-reality navigation system (AR navigation) is suggested recently. It provides navigational guidance by imposing graphical information on real image captured by camera mounted on a vehicle in real-time. The ultimate goal of navigation system is to assist the driving task with least driving workload whether it is based on the abstracted graphic paradigm or realistic image paradigm. In this paper, we describe the comparative studies on how map navigation and AR navigation affect for driving tasks by experimental research. From the result of this research we obtained a basic knowledge about the two paradigms of navigation systems. On the basis of this knowledge, we are going to find the optimal design of navigation system supporting driving task most effectively, by analyzing characteristics of driving tasks and navigational information from the human-vehicle interface point of view.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.14-21
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• 2013

In satellite operations and space exploration missions, a ranging is one of the most essential technologies to get its navigational information of space probes. Recently, the importance of cross-support between space agencies is increasing for more fine performance of space mission. For cross-support, mutually compatible ranging system between space agencies is recommended. For these reasons, the consultative committee for space data systems (CCSDS) recommends pseudo noise (PN) ranging as a digital standard ranging system. The length of PN sequence in CCSDS standard is proper for deep space missions, however, it is too long to use for ranging in near earth missions. In this paper, we propose Variable Length PN sequence schemes suitable for ranging of near earth satellites, such as low-earth orbit (LEO), medium-earth orbit (MEO) and Geostationary orbit (GEO). Therefore we propose variable length PN sequence ranging system including CCSDS standard for multiple missions.