• Journal of Ocean Engineering and Technology
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• v.24 no.1
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• pp.47-52
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• 2010

This study presents a modified scheme for the radar image simulation of sea waves. A simulated radar image was obtained by taking into account the dot product of the directed vector from the radar and the normal vector of the sea surface. Moreover, to calculate the radar image, we used the radar received power and radar cross section. To demonstrate the effectiveness of the proposed scheme, the wave spectrum from field data was utilized to obtain the simulated sea waves. The radar image was simulated using numerically generated sea waves. The wave statistics from the simulation agrees comparatively with those of the original field data acquired by real radar measurements.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.73-78
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• 2008

We introduce OBS and sonobuoy systems which are the typical wide-angle reflection/refraction seismic recorders made by KORDI for the investigation of crustal structure and the sediment/basement structure in the coastal area. These recording devices are examined for their usage through the test survey. The normal operation of these devices were proved and good recordings were obatined. The head waves are recognized in the sonobuoy records, which shows the possibility of velocity structure survey by the refraction and/or tomography method.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.519-524
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• 2006

This paper describes an application of information presentation based geographic map for maritime information, including navigation information. The work is motivated by the need to prepare maritime information representation and distribution for future generation Web network technology. This works consist of map generation using GML and application to maritime information. GML 3.0 became an adopted specification of the Open Geospatial Consortium(OGC) in January 2003, and is rapidly emerging as the world standard for the encoding, transport and storage of all forms of geographic information. This paper looks at the application of GML to one of the more challenging areas of maritime information. Specific features of GML of interest to maritime information provider are discussed and then illustrated through a series of maritime information case studies. The first phase of the work consists of the construction of GML application schema for using as a base map of maritime information. Maritime information is acquired from multiple sources, including standards documents, database schemas, lexicons, collections of symbol definition. The sources of GML ontological knowledge and the contribution of each source to the overall ontology are described in this paper. In the second phase, the prepared GML is used to create a prototype of the mixed maritime information as a base map - for tagging documents within the maritime domain. An overview of this prototype is included. One application area for these information elements described here is the integrated retrieval of maritime information from diverse sources, ranging from Web sites to nautical chart databases and text documents.

• Ocean Systems Engineering
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• v.6 no.3
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• pp.289-303
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• 2016

With more than 100 years exploration and development of offshore oil, more and more offshore oil fields will gradually lose the economic profit to operate. In this article, to take the target oil field for example, the procedure of decommissioning for FPSO, TCMS, subsea system and well abandonment have been analyzed. Meanwhile, the environment impact and mitigation measure have been proposed. The successful project experience will provide a guide line for the offshore facilities decommissioning and abandonment.

• Smart Media Journal
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• v.5 no.1
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• pp.9-14
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• 2016

Although the ocean observation and exploration equipment is necessary for the oceanographical observation and strengthening influence of the nation and the resource preemption, it depended on the oversees adoption rather than the domestic development. The MBESs were developed for seabed topography, sedimentary distribution information and underwater objects exploration, but there is no domestic production. So in this research we try the localization of the marine acoustic sounder. Especially about correcting the error occurred on the hardware, we confirmed it on software.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.44 no.3
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• pp.70-76
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• 2007

Hemire is a 6000m class deep-sea ROV, which is recently developed by Maritime & Ocean Engineering Research Institute (MOERI) of Korea Ocean Research & Development Institute (KORDI) for 6 years since 2001, sponsored by the Ministry of Maritime Affairs and Fisheries (MOMAF). Hemire dove upto 1,065m for the first east sea trial last April, and touched a 2,026m bottom of the east sea last September. Finally, last November, Hemire reached a 5,775m bottom of the pacific ocean successfully. This showed our own technologies for design and development of a deep-sea ROV as 4th nation in the world, and we made a great step forward for deep-sea exploration. This paper describes a general overview of a 6000m class deep-sea ROV, and briefly explains development procedure of Hemire and Henuvy. Finally, results of sea trial are summarized.

• Geophysics and Geophysical Exploration
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• v.25 no.2
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• pp.59-70
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• 2022

Recent studies demonstrate that machine learning has expanded in the field of seismic interpretation. Many convolutional neural networks have been developed for seismic sequence identification, which is important for seismic interpretation. However, expense and time limitations indicate that there is insufficient data available to provide a sufficient dataset to train supervised machine learning programs to identify seismic sequences. In this study, patch division and data augmentation are applied to mitigate this lack of data. Furthermore, to obtain spatial information that could be lost during patch division, an artificial channel is added to the original data to indicate depth. Seismic sequence identification is performed using a U-Net network and the Netherlands F3 block dataset from the dGB Open Seismic Repository, which offers datasets for machine learning, and the predicted results are evaluated. The results show that patch-based U-Net seismic sequence identification is improved by data augmentation and the addition of an artificial channel.

• Journal of Ocean Engineering and Technology
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• v.17 no.6
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• pp.38-46
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• 2003

Aim of this article is to propose Micro-Genetic Simulated Annealing (${\mu}GSA$) as a hybrid metaheuristics approach to find the global optimum of nonlinear optimisation problems. This approach combines the features of modern metaheuristics such as micro-genetic algorithm (${\mu}GAs$) and simulated annealing (SA) with the general robustness of parallel exploration and asymptotic convergence, respectively. Therefore, ${\mu}GSA$ approach can help in avoiding the premature convergence and can search for better global solution, because of its wide spread applicability, global perspective and inherent parallelism. For the superior performance of the ${\mu}GSA$, the five well-know benchmark test functions that were tested and compared with the two global optimisation approaches: scatter search (SS) and hybrid scatter genetic tabu (HSGT) approach. A practical application to structural sandwich panel is also examined by optimism the weight function. From the simulation results, it has been concluded that the proposed ${\mu}GSA$ approach is an effective optimisation tool for soloing continuous nonlinear global optimisation problems in suitable computational time frame.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.293-298
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• 2005

In this study, we have developed the high resolution multichannel seismic data acquisition system and shallow marine seismic source. It is easy to operate and handle our source system which utilizes piezoelectric transducer of high electrical power. We have manufactured two 4-channel streamers for multi-channel marine seismic survey. In the recording part, we used 24bits and 8 channel high speed A/D board. Therefore, we could achieve the improvement of data quality and the efficiency of data acquisition. We compared the developed system with the conventional system to demonstrate its field applicability.

• International Journal of Ocean System Engineering
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• v.3 no.4
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• pp.175-187
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• 2013

Moonpools are vertical wells in a floating body used onboard many types of vessels like Exploration and drilling vessels, Production barges, Cable-laying vessels, Rock dumping vessels, Research and offshore support vessels. Moonpool gives passage to underwater activities for different types of ships as per their mission requirements. It is observed that inside a moonpool considerable relative motions may occur, depending on shape, depth of the moonpool and on the frequency range of the waves to which the ship is exposed. The vessel responses are entirely different in zero and non-zero Froude number. Former situation is paid attention in this study as the mission requirement of the platform is to be in the particular location for long period of operation. It is well known that there are two modes of responses depending on the shape of the moonpool viz., piston mode for square shape and sloshing mode for rectangular shapes with different aspect ratios of opening like 1:1.5 and 1:2 ratios. Circular shaped moonpool is also tested for measuring the responses. The vessel moored using heavy lines are modelled and tested in the wave basin. The pretensions of the lines are varied by altering the touchdown points and the dynamic tensions on the lines are measured. The different modes of oscillations of water column are measured using wave gauge and the vessel response at a particular situation is determined. RAOs calculated for various situations provide better insight to the designer.