• Journal of the Korean Institute of Telematics and Electronics
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• v.18 no.2
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• pp.22-26
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• 1981

Truncated expansions based upon the sampling theorem but containing only a few terms can be very useful for practical interpolations of band-limited or narrow-band random signals. The major goal of this work is to find and coiupare efficient and "statistically accurate" algorithms for the dynamic analysis of the ocean systems. The stalistical accuracy of truncated sampling interpolations is investicated, and one simple ocean systems, which yields a Runge-Kutta simulation algorithm of improved accuracy with very little increase in computation, is indicated.indicated.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.37 no.5
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• pp.315-322
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• 2019

DSM (Digital Surface Model) is a digital representation of ground surface topography or terrain that is widely used for hydrology, slope analysis, and urban planning. Aerial photogrammetry and LiDAR (Light Detection And Ranging) are main technology for urban DSM generation but high-resolution satellite imagery is the only ingredient for remote inaccessible areas. Traditional automated DSM generation method is based on correlation-based methods but recent study shows that a modern pixelwise image matching method, SGM (Semi-Global Matching) can be an alternative. Therefore this study investigated the application of SGM for Kompsat satellite data of KARI (Korea Aerospace Research Institute). Firstly, the sensor modeling was carried out for precise ground-to-image computation, followed by the epipolar image resampling for efficient stereo processing. Secondly, SGM was applied using different parameterizations. The generated DSM was evaluated with a reference DSM generated by the first pulse returns of the LIDAR reference dataset.

• Journal of the Korean Society for information Management
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• v.31 no.1
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• pp.163-187
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• 2014

The purpose of this study is to explain information usage behavior of researchers in the field of ocean science and technology. The study mainly collected primary data for advancement of special library services as well as establishment of personalized information services based on personal characteristics such as age, education level, and area of research. The data collection was conducted for two weeks during January 2014, through a web survey to 348 researchers in national ocean research institutions in South Korea. Total of 115 researchers replied. The analysis showed that the most preferred type of information medium was a scholarly journal. Researchers used more foreign published journals compared to Korean ones, while favoring digital formats rather than printed ones. The top channels for information collection were 'web search' and 'affiliated libraries.' Most pointed out difficulties of data collection were 'lack of variety of digital resources in affiliated libraries' and 'reluctance to use charged information.' Key elements for satisfactory user experience were ranked in the order of 'digital library system,' 'library staff,' and 'library collection' and so on;which proves the close relationship between library service and information usage service satisfaction. The result of an assessment for demands in special libraries showed that 'personalized information search service,' 'project support service,' and 'research direction analysis service' should be implemented in the future.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.89-90
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• 2008

We present an implementation and it's real-sea test of an underwater acoustic communication system, which allows the system to reduce complexity and increase robustness in time variant underwater environments. For easy adaptation to complicated and time-varying environments of the ocean, all-digital transmitter and receiver systems were implemented. For frame synchronization the CAZAC sequence was used, and QPSK modulation/demodulation method with carrier frequency of 25kHz and a bandwidth of 5kHz were applied to generate 10kbps transmission rate including overhead. To improve transmission quality, we used several techniques and algorithms such as adaptive beamforming, adaptive equalizer, and convolution coding/Viterbi decoding. For the verification of the system performance, measurement of BER has been done in a very shallow water with depth of 20m at JangMok, Geoje. During the experiment, image data were successfully transmitted up to about 9.6km.

• Journal of Ship and Ocean Technology
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• v.8 no.4
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• pp.45-55
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• 2004

How to achieve engineering collaboration among diverse engineering activities is one of the key topics in manufacturing fields nowadays. The infrastructure for collaborative engineering is essential, and it can be realized by information technologies and intelligent engineering applications in digital environments. Digital Manufacturing is a technology to facilitate effective product developments and agile productions by computer models representing the physical and logical schema and the behavior of real manufacturing systems including products, processes and factories. A digital factory as a well-designed and integrated digital environment is incorporated in it. In this paper, digital manufacturing is recommended as a good strategy for collaborative engineering, especially in product developments and productions. By business process analysis and some case studies, we suggested sophisticated digital models are very useful to concurrent and collaborative engineering. It is expected that digital manufacturing is a very good strategy for achieving dramatic time and cost savings in many engineering activities of many manufacturing industries, including machinery, automotive and shipbuilding.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.10-16
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• 2003

Under the concept of global economy, the enterprises are assigning design and production environments around the world in different areas. In shipbuilding companies, a serious problem of information exchange emerges as companies use traditional hardware and very distinct softwares appropriate to their field of expertise. To overcome the decreased productivity due to the interruption of information, the concept of simultaneous engineering and concurrent design becomes very significant. In this article, the concept oj collaborative design based on internet environments is described. Especially, the core technologies to achieve collaborative design environments among shipbuilding companies, ship owners, ship classification societies, model basin, and consulting companies are adopted.

• Journal of Digital Contents Society
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• v.19 no.8
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• pp.1593-1601
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• 2018

The International Hydrographic Organization has developed the S-100 standard as a geospatial standard to express various types of hydrographic information. Product specification describes information of data on ENC such as definition, structure, data model, etc. S-129 PS is for under keel clearance management information. In this paper, to help developers to implement S-129 PS using the technology of S-100, we analyze the process to portray the S-100 based data and then implement a case study. This paper introduces the XSLT processing of portrayal engine to reform the generated data set, and the generation of drawing instructions to display the data set on the electronic chart. A case study is experimented to display the portrayal output of under keel clearance management on an electronic chart.

• Journal of Navigation and Port Research
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• v.34 no.1
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• pp.9-14
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• 2010

Nautical Publications is a special purpose book, or a specially compiled database, that is issued officially by or on the authority of a Government, authorized Hydrographic Office and is designed to meet the requirements of marine navigation such as SOLAS and PSC. Nautical publications include List of Lights, Sailing directions. The SNPWG(Standardization Nautical Publications Working Group) from the IHO is working to implement in computer systems all those elements of interest for Hydrography and Navigation Concerning nautical publications' digitization process, the SNPWG has defined three types of nautical publications: Type 1 : Hard copy(NP1), Type 2 : Digital version, A slight modification of type 1(NP2), Type 3 : Digital version for ECDIS(NP3). Nautical Publications is essential with nautical charts as reference information to navigate. Development of digital nautical publications is needed for liaison with the chart production system, up-to-dateness of hydrographic information, improvement of service. But, Korean status is positioned in NP1. In our study, we surveyed the present status of nautical publications for development strategy of digital nautical publications. We build database of south coast of sailing direction, develop a manager program, convert the contents to KML( Keyhole Markup Language), develop a user program.

• Ocean and Polar Research
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• v.35 no.3
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• pp.239-247
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• 2013

Digital image processing is a process to analyze a large volume of information on digital images. In this study, Artemia hatching rate was measured by automatically classifying and counting cysts and larvae based on color imaging data from cyst hatching experiments using an image processing technique. The Artemia hatching rate estimation consists of a series of processes; a step to convert the scanned image data to a binary image data, a process to detect objects and to extract their shape information in the converted image data, an analysis step to choose an optimal discriminant function, and a step to recognize and classify the objects using the function. The function to classify Artemia cysts and larvae is optimally estimated based on the classification performance using the areas and the plan-form factors of the detected objects. The hatching rate using the image data obtained under the different experimental conditions was estimated in the range of 34-48%. It was shown that the maximum difference is about 19.7% and the average root-mean squared difference is about 10.9% as the difference between the results using an automatic counting (this study) and a manual counting were compared. This technique can be applied to biological specimen analysis using similar imaging information.

• Journal of Ocean Engineering and Technology
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• v.19 no.2 s.63
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• pp.74-81
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• 2005

A 3-D localization method of an autonomous underwater vehicle (AUV) has been developed, which can solve the limitations oj the conventional localization, such as LBL or SBL that reduces the flexibility and availability of the AUV. The system is composed of a mother ship (small unmanned marine prober) on the surface of the water and an unmanned underwater vehicle in the water. The mother ship is equipped with a digital compass and a GPS for position information, and an extended Kalman filter is used for position estimation. For the localization of the AUV, we used only non-inertial sensors, such as a digital compass, a pressure sensor, a clinometer, and ultrasonic sensors. From the orientation and velocity information, a priori position of the AUV is estimated by applying the dead reckoning method. Based on the extended Kalman filter algorithm, a posteriori position of the AUV is, then, updated by using the distance between the AUV and a mother ship on the surface of the water, together with the depth information from the pressure sensor.