• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.1 s.20
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• pp.1-7
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• 2004

RADARSAT is one of many possible data sources that can play an important role in marine surveillance including ship detection because radar sensors have the two primary advantages: all-weather and day or night imaging. However, atmospheric effects on SAR imaging can not be bypassed and any remote sensing image has various geometric distortions, In this study, radiometric and geometric calibrations for RADARSAT/SAT data are tried using SGX products georeferenced as level 1. Even comparison of the near vs. far range sections of the same images requires such calibration Radiometric calibration is performed by compensating for effects of local illuminated area and incidence angle on the local backscatter, Conversion method of the pixel DNs to beta nought and sigma nought is also investigated. Finally, automatic geometric calibration based on the 4 pixels from the header file is compared to a marine chart. The errors for latitude and longitude directions are 300m and 260m, respectively. It can be concluded that the error extent is acceptable for an application to open sea and can be calibrated using a ground control point.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.4
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• pp.169-181
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• 2009

IMO adopt the revision of SOLAS convention on requirement systems for ECDIS and considered an ECDIS as the major system for E-Navigation strategy on marine transportation safety and marine environment protection. ENC(Electronic Navigational Chart) as base map of ECDIS is considered as a principal information infrastructure that is essential for navigation tasks. Though ECDIS has many advantages, it's almost impossible for the mariner to recognize the displayed information because of intense display of objects so called the clutter. In this paper, the current status and international standards on SCAMIN((Minimum Scale) attribute have been investigated. Also improvement of SCAMIN attribute of ENCs and grouping method for the sounding values was proposed.

• Korean Journal of Geomatics
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• v.3 no.1
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• pp.7-14
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• 2003

For GIS to land and sea in Korea, GIS on land was almost completed with big cities by NGIS(National Geographic Information System) business. However, MGIS(Marine Geographic Information System) being constructed by the National Oceanographic Research Institute is still constructing geography information and definition of attribute information and real condition. We are being studied on research to get maximized the ripple effect linking GPS and Navigation techniques on GIS. GPS in accuracy is divided into navigation and precise surveying equipment. Now, GPS technology has been developed very much and low price GPS equipments are introducing. But expense on GPS equipment is high yet. Therefore, GPS equipment for navigation is used on cheap GPS equipment in a car or ship. In this paper, the author used algorithm to convert ellipsoid coordinate between WGS84 and Bessel ellipsoid and to analyze map projection between BESSEL ellipsoid and UTM plane coordinate system. And the author developed ship navigation system with cheap GPS equipment using algorithm of ellipsoid conversion and map projection. The author proposed the necessity on constructing MGIS to manage many ships.

• Ocean and Polar Research
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• v.28 no.1
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• pp.13-23
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• 2006

This study was conducted to investigate the community structure and distributional pattern of meiobenthos on the sediment of the mangrove forest and seagrass bed in the Chuuk lagoon. The samples were collected by an acryl corer at 14 stations. Nematodes were the most abundant meiobenthos, followed by ciliophorans and polychaetes; these taxa comprised more than 70% of the total abundance at all stations. The meiofuuna sampled in seagrass bed were more diverse than those of mangrove substrates. Total densities were higher in mangrove stations than other sites, averaging 1,671 to $2,967inds/10cm^2$. Densities in seagrass area ranged between 605 and $1,053inds/10cm^2$. Biomasses, however, were higher in seagrass bed $(975-2,167{\mu}g\;free\;dry\;weight/10cm^2)$ than in mangrove area $(1,064-1,180{\mu}g\;free\;dry\;weight/10cm^2)$. Ordination chart by MDS of major meiofaunal density in each station showed difference between mangrove area and seagrass area in terms of habitat of meiobenthos.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.8
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• pp.698-703
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• 2016

Francis hydro turbines have been most widely used throughout the world because of their wide range of head and flow rate applications. In most applications, they are used for high heads and flow rates. Currently, Korea is developing technology for Francis hydro turbine design and manufacture. In order to understand the internal details of Francis hydro turbines further, a new Francis turbine model runner is designed and model internal flow characteristics are investigated. The specific speed of the Francis hydro turbine model runner is $Ns=200m-kW-min^{-1}$. The runner blade is designed successfully according to the port area and one-dimensional loss analysis. The best efficiency point of the Francis hydro turbine model achieves 90% at the design condition. CFD analysis yields a hill chart of the Francis hydro turbine model for use in predicting performance.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.1
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• pp.63-69
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• 2001

Many countries are producing the ENC(Electronic Navigational Chart)for their own waters and developing the electronic navigational equipment such as ECS, and ECDIS. Though ECDIS has many advantages, it is almost impossible for the mariner to recognize the displayed information because of intense display of objects so called as the clutter. In this paper, the problem of scale factor has been investigated and now methods, variable factor system, to assign the scale factor were proposed.

• Korean Journal of Computational Design and Engineering
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• v.18 no.3
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• pp.224-233
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• 2013

For the scheduling and the job assignment of the ship hull production design which is a process-based work, we suggest the simulation-based scheduling using the discrete-event-based business process simulation. First, we analyze the ship hull production design process from the perspective of a job assignment to make it into the simulation model using DEVS (Discrete Event System Specification) which is the representative modeling method for a discrete-event simulation. Based on the APIs of the open-source discrete-event simulation engine, we implement the simulation using the Groovy script. We develop the scenario generator in which the user defines detail information of the construction drawing and its member blocks, and design engineers information, and the various setting for the simulation including the job assignment strategy. We use the XML files from this scenario generator as inputs of simulation so that we can get simulation result in forms of Gantt chart without changes of the simulation model.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.3
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• pp.259-265
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• 2015

It is clearly understood that e-navigation is beneficial to prevent collision and grounding of ships. The purpose of this study is to define and present a future ship operation system under the e-navigation environment in order to provide clear direction for the design of Korean e-navigation system. The future ship operation system consists of shipboard navigational system, shore supporting system and maritime communication system. To achieve the objectives of this study, the ship operation system was discussed separately into SOLAS ships and non-SOLAS ships in this study. In SOLAS ships, mariners become a system manager, choosing system presets, interpreting system output, and monitoring vessel response. In small ships and fishing vessels, mariners may enjoy their navigation by using the automatic tracking of ship's position on the portable electronic chart display. The improved bridge design, integrated and harmonized navigational system and single window reporting will reduce significantly the administrative and physical workload of mariners. Mariners can concentrate their attention more on navigational duty under the e-navigation environment. To build an effective Korean e-navigation system, the essential navigational functions and e-navigation services for small ships and fishing vessels must be identified and developed taking into account user needs.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.32-42
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• 2006

This study aims at establishing a technique for sailing yachts model tests with sailing condition. It is very important to estimate a ship's potential speed performance before building a real ship. Several methods are used to estimate a ship's potential speed performance such as using parent ship data, standard vessel chart and model test. Model test is the most precise among these options. In korea. model testing is widely used with general vessels but not with sailing yachts. Because sailing yachts are propelled with heeling and leeway. using the wind. another method is needed to estimate their speed. The new model test. which is different from tests for upright general vessels, is in a great demand. In this paper. we describe a test method for the sailing yacht model test. based on Masuyama's equation of motion. And we describe choosing scale ratio. production process and materials of the model. Also. various ways of measuring instruments. attaching jigs and adjusting calibration are described so that they can be utilized as useful data for model testing.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.3
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• pp.429-438
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• 2021

The mandatory installation of the ECDIS (Electronic Chart Display and Information System) became an important navigational equipment for navigation officer. In addition, ECDIS is a key component of the ship's digitalization in conjunction with various navigational equipment. Meanwhile, cyber-attacks emerge as a new threat along with digitalization. Damage caused by cyber-attacks is also reported in the shipping sector, and IMO recommends that cybersecurity guidelines be developed and included in International Security Management (ISM). This study analyzed the cybersecurity hazards of ECDIS, where various navigational equipment are connected. To this end, Importance-Performance Analysis (IPA) was conducted on navigation officer using ECDIS. As a result, the development of technologies for cyber-attack detection and prevention should be priority. In addition, policies related to 'Hardware and Software upgrade', 'network access control', and 'data backup and recovery' were analyzed as contents to be maintained. This paper is significant in deriving risk factors from the perspective of ECDIS users and analyzing their priorities, and it is necessary to analyze various cyber-attacks that may occur on ships in the future.