• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.397-398
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• 2010

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.49-58
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• 2008

The function of river navigation is being reconsidered from the viewpoints of environment-friendly and energy-efficient, easing traffic congestion, emergency transport in disaster, and supporting tourism and recreation activities, etc. The purpose of this study is to identify current trends and problems of river navigation in Japan and indicate the role that river navigation should play in future and the directionality of development. This study focused on disaster prevention function with especially high importance degree in metropolitan area from among various functions of river navigation, and showed potential of river navigation corresponding to stranded commuter who is examined as a serious problem in government.

• The Journal of Korea Robotics Society
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• v.19 no.1
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• pp.92-97
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• 2024

This paper provides a study of distributional perspective on reinforcement learning for application in mobile robot navigation. Mapless navigation algorithms based on deep reinforcement learning are proven to promising performance and high applicability. The trial-and-error simulations in virtual environments are encouraged to implement autonomous navigation due to expensive real-life interactions. Nevertheless, applying the deep reinforcement learning model in real tasks is challenging due to dissimilar data collection between virtual simulation and the physical world, leading to high-risk manners and high collision rate. In this paper, we present distributional reinforcement learning architecture for mapless navigation of mobile robot that adapt the uncertainty of environmental change. The experimental results indicate the superior performance of distributional soft actor critic compared to conventional methods.

• Journal of the Korean Society of Marine Environment & Safety
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• v.3 no.S1
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• pp.55-73
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• 1997

It is well known that simulation study in the preliminary design stage of harbors or berths is of great use, since it can provide helpful informations to the designer from the view point of ship navigations. In this paper, a brief review is made in the safety assessment of ship navigation for a 320,000 DWT VLCC entering Yecocheon harbor area, which is carried out by shiphandling simulator system. The geographic data base for the harbor as well as the mathematical models of the ship and environmental effects are designed and developed. Based in the on-site inspections and interviews with pilots in Yeocheon area, basic maneuvering plans and consistence with real operation conditions. Berthing and deberthing maneuvering simulations as well as approaching and departing simulations are carried out by 3 experienced navigators according to the maneuvering plans and environmental scenarios. The simulation results are analysed in various ways to evaluate the quantitative and qualitative maneuvering difficulties and thereby to assess the safety of ship navigation in that area.

• Journal of Navigation and Port Research
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• v.27 no.6
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• pp.645-652
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• 2003

A virtual vessel traffic control system is introduced to contribute to prevent a marine accident such as collision and stranding from happening. Existing VTS has its limit. The virtual vessel traffic control system consists of both data acquisition by satellite remote sensing and a simulation of traffic environment stress based on the satellite data, remotely sensed data And it could be used to provide timely and detailed information about the marine safety, including the location, speed and direction of ships, and help us operate vessels safely and efficiently. If environmental stress values are simulated for the ship information derived from satellite data, proper actions can be taken to prevent accidents. Since optical sensor has a high spatial resolution, JERS satellite data are used to track ships and extract their information. We present an algorithm of automatic identification of ship size and velocity. It lastly is shown that based on ship information extracted from JERS data, a qualitative evaluation method of environmental stress is introduced.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1997.10a
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• pp.35-41
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• 1997

China has integrated maritime safety system which positively and effectively ensures safe navigation and environmental protection. This paper gives brief account on maritime safety rules and regulations, adminstrations and management mechanism, navigation aids and facilities, maritime communication and GMDSS etc. China is a developing country with fast economical growth. With a long coastline of 18,000 kilometers, and 5,000 more islands, China has a fairly developed shipping industry. China also sits in IMO Council as A member. In China , there are over 200 ports with an annual hadnling capacity of over 10,000 tons of cargo ; there are over 4,000 coasters and ocean-going ships with more than 3 million seafarers of which 1/3 being officers ; there are an aggregate gross tonnage 17 million gt for merchant ships. China ranks No.5 shipping country in the world as shown by Lloyd's Maritime Information Services Ltd. 1995. The Chinese shipping industry plays an important role in both domestic transportation and foreign trade. The Chinese government always attaches great importance to maritime safety . Since 1949, and from the adoption of reform-opening policy, China has gradually formed an integrated maritime safety system.

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.69-73
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• 2007

The recent huge maritime casualties and their environmental impacts showed that human error in ship navigation is one of the primary causes leading to accidents. In order to reduce maritime accidents and human errors in ship navigation, it is very important and urgent to improve the skills of navigators and develop advanced navigation support system for ship operations. For example, a SCMS(Ship Control and Management System), INS(Integrated Navigation System) and PCS(propulsion Control System) which are considered as a ship automation system was operated in ship. Furthermore, the most recent automation ships collision incidents warn us that only making automation ships alone is not sufficient for improving ship safety. Effective interaction between officer and ship automation system is essential for safety. In this paper, the interactive relationship between officer and the ship automation system was studied, then the research result for reducing maritime casualties will be presented.

• The Journal of Korea Robotics Society
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• v.12 no.4
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• pp.385-394
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• 2017

Side scanning sonar (SSS) provides valuable information for robot navigation. However using the side scanning sonar images in the navigation was not fully studied. In this paper, we use range data, and side scanning sonar images from UnderWater Simulator (UWSim) and propose measurement models in a feature based simultaneous localization and mapping (SLAM) framework. The range data is obtained by echosounder and sidescanning sonar images from side scan sonar module for UWSim. For the feature, we used the A-KAZE feature for the SSS image matching and adjusting the relative robot pose by SSS bundle adjustment (BA) with Ceres solver. We use BA for the loop closure constraint of pose-graph SLAM. We used the Incremental Smoothing and Mapping (iSAM) to optimize the graph. The optimized trajectory was compared against the dead reckoning (DR).

• Journal of Environmental Science International
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• v.30 no.3
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• pp.257-266
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• 2021

This study explored measures to reduce noise applicable to Gimhae international airport centering on densely packed housing areas. Especially, as for measures to relieve noise damage on the densely packed housing areas in Gimhae-si, the noise reduction effect is expected to be doubled if the west runway (36L/18R) is used as the preferred runway for the 36 direction takeoff, as well as if the flight bypasses the densely packed housing areas by means of sophisticated navigation using the area navigation (RNAV) procedure based on performance-based navigation (PBN). Takeoff toward the south connects the flight path to the South Sea which has comparatively low noise impact, relieving noise damage on the densely packed housing areas (apartment complexes in Naeoe-dong of Gimhae-si, etc.) near the northern end of the runway. The operation of the runway displaced threshold is currently being implemented on the west runway (36L/18R) of Gimhae international airport. It has been found that swing landing in spring and summer when the wind blows from the south has a noise reduction effect on the noise sensitive areas at the side and end of the west runway (Gangdong-dong and Jukdong-dong of Gangseo-gu and Buram-dong of Gimhae-si, etc.).

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.1
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• pp.11-17
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• 2023

In this study, the correlation analysis between total system error and environmental factor variables was performed to confirm the effect on the performance of the integrated navigation system by various environmental factors. To collect flight data of hybrid vertical take-off and landing UAVs, scenarios including various turning sections and straight sections such as left turn, right turn, turning rate, and path change angle were selected, and environmental data of wind direction, wind speed, temperature, air pressure, and humidity were collected in real time through weather station. As a result of the correlation analysis between the collected flight data and environmental data, it was concluded that the performance of the integrated navigation system by environmental factors within the collected data was not significant affected and was robust.