• Journal of the Korea Institute of Military Science and Technology
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• v.21 no.4
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• pp.429-436
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• 2018

The RCS value of maritime ship is indicator of ship's stealth performance and it should be particularly measured for navy ship to ensure survivability on the battlefield. In the design phase of the navy ship, a RCS prediction should be performed to reduce RCS value and achieve ROC(Required Operational Capability) of the ship through configuration control. In operational phase, the RCS value of the ship should be measured for verifying the designed value and obtaining tactical data to take action against enemy missile. During the measurement of RCS for the ship, ship motion can be affected by roll and pitch in accordance with sea state, which should be analyzed into threat elevation from view point of enemy missile. In this paper, we propose a method to measure and analyze RCS of ship in 3-dimensions using a ship motion measuring instrument and a fixed RCS measurement system. In order to verify the proposed method, we conducted a marine experiment using a test ship in sea environment and compared the measurement data with RCS prediction value which is carried by prediction SW($CornerStone^{TM}$) using CAD model of the ship.

• Journal of the korean society of oceanography
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• v.34 no.4
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• pp.200-206
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• 1999

Seawater sampling is the primary task for the study of the marine environmental parameters that require shipboard or laboratory experiments for their analyses, and is also required for the calibration of some instruments for in situ measurement. A new automatic bottle (AUTTLE) is developed for seawater sampling at any desired time and water depth by self-triggering. Both any type of single or assembled mooring for 15 days and manual actuation by using a remote messenger as existing instantaneous single point water samplers are possible. Its sampling capacity and the resolution of time setting are 2 liters and 1 second, respectively. The result of a field experiment with an optical backscattering sensor (OBS) and a total of 14 AUTTLES for the in situ calibration of the OBS shows that the AUTTLE must improve our understanding on the behavior of the sand/mud mixtures in the environments with high waves and strong tides. The AUTTLE will serve as a valuable instrument in the various fields of oceanography, especially where synchronized seawater sampling at several sites is required and/or the information in storm period is important.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.29-33
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• 2007

On-site measurement of ship wave has been carried out in the vicinity of Mokpo inner harbour. The wave data were collected and logged 5Hz by the ultrasonic instrument during 12hour May 17th 2006. The number of data is 216,000 and the maxinum wave heght is 81.41cm in normal weather condition It is found that the wave conditions in this water area are predominantly affected by the ship-generated waved under normal condition By comparing with the wind-generated waves in the open region which are irregular but with dominant directional characteristics, the existing harbor wave field is much more complex.

• Journal of the Society of Naval Architects of Korea
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• v.50 no.5
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• pp.349-354
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• 2013

The blades of flexible propellers are formed by overlaying and adhering many layers of thin glass-fiber fabric sheets, are compressed and dried in the rigid mold. The current manufacturing process can not avoid the rather irregular deformation of the blades composed of non-isotropic non-uniform fabric structures, and inevitably introduces the different shape-forming errors between blades. In this paper, several flexible model propellers are precisely measured with three-dimensional optical instrument and compared with the original design geometry. The model propellers with the as-measured geometry are evaluated with the lifting-surface-theory-based propeller analysis code. The open-water performance are presented and discussed. The importance of the manufacturing accuracy is addressed to be able to apply the flexible propellers for propulsion of marine vehicles.

• Ocean and Polar Research
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• v.32 no.3
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• pp.267-268
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• 2010

Many countries has been interested in studying the East Sea to look ahead into the world oceans' future, since the East Sea has been known as a miniature ocean. In this respect, PICES decided the East Asian Seas Time-series (EAST) studies, and the East Sea as the first subject (EAST-I). Since 2006 Ministry of Land, Transport & Maritime Affairs, Korea has supported the Korean EAST-I program. Through the Korean EAST-I program, 44 research papers were published in various scientific journals. This special issue contains 6 research articles including results from the interdisciplinary observation in the summer, 2008. Those articles cover the entire East Sea from the Korea Strait to the Japan Basin, and also cover the studies of the euphotic layer to the bottom sediment. MLTM and KIMST have provided full support to EAST-I program. KHOA carried out the joint cruises in the Ulleung Basin. Those are deeply appreciated. Finally, we would like to express our gratitude to the editorial board of Ocean & Polar Research.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.988-991
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• 2015

3D printing technology is instrument that can create real objects in three-dimensional space, as printed on paper, if the three-dimensional designs are made. 3D printing technology has been recently used in various field of medicine, and also biomedical application of three dimensional printing technology remains one of the most important research topics until now. 3D printing technology is causing a revolutionary change in the overall automotive manufacturing, aerospace, marine, medical and so on. The medical industry applications of current 3D printer are a virtual simulation, custom medical implants manufactured, practice of medical personnel. In this study, we analyzed 3D printing technology and application cases for medical services.

• Journal of Korean Port Research
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• v.7 no.1
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• pp.89-114
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• 1993

ICLL 66 is the most widely ratified instrument of the IMO and is, along with the International Convention on Safety of life at Sea (SOLAS), the primary document setting forth internationally agreed ship safety standards. ICLL 66 set freeboard requirement based on experience gained from the first Load Line Convention in 1930 and on contemporary developments in ship design. Reexamination of ICLL 66 is indicated by the proliferation of novel ship designs for which it lacks adequate regulations and by significant advancements in analytical seakeeping and deck wetness prediction techniques now available to the designer. In this paper, the Freeboard Advisory Group reviews these issues against the changing climate of the marine industry and maritime administrations, discusses the state of the art in analytical seakeeping programs, and outlines a series of recommendations for the establishment of a new international load line convention for the next century. The steps needs for an international program at IMO are discussed and a new convention is proposed.

• Journal of Ocean Engineering and Technology
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• v.27 no.6
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• pp.100-105
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• 2013

This paper presents a sea surface reconstruction method that uses measured radar images by applying filtering techniques and identifying wave characteristics of the surrounding the Ieodo ocean research station using WaveFinder (X-band wave measurement radar), which is installed in the station. In addition, the results obtained from real radar images are used to verify the reconstructed sea surface. WaveFinder is a marine system that was developed to measure wave information in real time. The WaveFinder installed in the station could acquire sequent images for the sea surface at constant time intervals to obtain real time information (Wave height, mean wave period, wave directionality, etc.) for the wave by getting a three-dimensional spectrum by applying an FFT algorithm to the acquired sequent images and wave dispersion relation. In particular, we found the wave height using the SNR (Signal to noise ratio) of the acquired images. The wave information measured by WaveFinder could be verified by comparing and analyzing the results measured using the wave measurement instrument (Sea level monitor) in the station. Additionally, the wave field around the station could be reconstructed through the three-dimensional spectrum and the inverse FFT filtering from the analyzed results for the measured radar images. We verified the applicability of the sea surface reconstruction method by comparing the measured and simulated sea surfaces.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.243-251
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• 2012

Real-time monitoring for environmental factors(temperature, salinity, chlorophyll, etc.) and carbonate components( pH and $fCO_2$) was conducted during 5-6th of July, 2012 at a seaweeds farm in Gijang, Busan. Surface temperature and salinity were ranged from $12.5{\sim}17.6^{\circ}C$ and 33.7~34.0, respectively, with highly daily and inter-daily variations due to tide, light frequency(day and night) and currents. Surface $fCO_2$ and pH showed a range of $381{\sim}402{\mu}atm$ and 8.03~8.15, and chlorophyll-a concentration in surface seawater ranged 0.8~5.8 ${\mu}g\;L^{-1}$. Environmental and carbonate factors showed the highest/lowest values around 5 pm of 5th July when the lowest tidal height and strongest thermocline in the water column, suggesting that biological production resulted in decrease of $CO_2$ and increase of pH in the seaweed farm. Processes affecting the surface $fCO_2$ distribution were evaluated using a simple budget model. In day time, biological productions by phytoplankton and macro algae are the main factors for $CO_2$ drawdown and counteracted the amount of $CO_2$ increase by temperature and air-sea exchange. The model values were a little higher than observed values in night time due to the over-estimation of physical mixing. The model suggested that algal production accounted about 14-40% of total $CO_2$ variation in seaweed farm.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.11
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• pp.1647-1653
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• 2010

Glycosaminoglycan (GAG) was purified from polysaccharide extracted from sea hare muscle on DEAE-Sepharose column and investigated for the functional groups, distribution of sugars, composition of disaccharide and structure of GAG. Purified GAG was composed of disaccharide above 55% of total sugar. Purified GAG showed amide I peak in 1648/cm and C-O stretch peak as properties of carbohydrate, amino acid peak in 1457/cm, and peak in 866/cm as properties of monosaccharide by FT-IR. Fucose, N-acetylgalactosamine, N-acetylglucosamine, glucose, galactose, mannose and xylose were found in MALDI-TOF MS/MS spectra of hydrolysates by chondroitin sulfate ABC lyase and heparanase I. Purified GAG was expected to be heparan sulfate including N-acetylgalactosamine and N-acetylglucosamine above 70% of total sugar. The structure of GAG was supposed as GlyUA(2S)-GlcNS and GlyUA-GlcNS(6S) with O-linkage on protein core.