• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.1 s.28
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• pp.21-28
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• 2007

The purpose of this study was to observe the effect on the water quality and sediment environment by the use of Nano-S for anti-Red tide material. The experiment was performed at subtidal and intertidal zone during six months(from Aug 2005 to Feb. 2006). The experiment sites were divided with concentration of materials. One is lower concentration(0.1%) and the other is higher concentration(1%). The results of experiments didn't show the remarkable influence of the materials effect before and after applying the Nano-S and the red mud. pH, salinity and DO were slowly increased during experiment period but nutrients were conversely decreased in the seawater. In the subtidal zone, qualities of sediments, IL, AVS and COD, were gradually lowered and the similar results were appeared in the intertidal zone. These results showed similar trends over all the experiment sites including control site. The results of heavy metals also did not show the interest different effect before and after applying the Nano-S and red mud compared with control site.

• Ocean and Polar Research
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• v.39 no.2
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• pp.159-168
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• 2017

To evaluate the accuracy of UAV photogrammetry for Hyangho coast, eastern coast of Korea, we conducted a field experiment wherein UAV photogrammetry test was repeated three times. Since the Haygho coast is located within a military reservation zone, it was necessary to obtain permission to gain access to the beach and to have sensitive aerial photographs showing military facilities inspected and cropped. The standard deviation of the UAV shooting position between the three tests was less than 1 m, but repeatability of footprint on the ground was low due to wind-driven variability of the UAV pose. Self-calibrating bundle adjustment(SCBA) of implementing non-metric camera calibration was failed in one test. In two tests, the vertical error was twice as large as the pixel size except for those areas that were subject to security inspection and cropping. Given the problems that can arise with regard to the repeatability of the shooting area as well as the possibility of failure with regard to SCBA, we strongly recommend that UAV photogrammetry in coastal areas needs to be repeated at least twice.

• Geophysics and Geophysical Exploration
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• v.5 no.4
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• pp.262-271
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• 2002

This study presents a practical procedure for the Bayesian inversion of geophysical data. We have applied geostatistical techniques for the acquisition of prior model information, then the Markov Chain Monte Carlo (MCMC) method was adopted to infer the characteristics of the marginal distributions of model parameters. For the Bayesian inversion of dipole-dipole array resistivity data, we have used the indicator kriging and simulation techniques to generate cumulative density functions from Schlumberger array resistivity data and well logging data, and obtained prior information by cokriging and simulations from covariogram models. The indicator approach makes it possible to incorporate non-parametric information into the probabilistic density function. We have also adopted the MCMC approach, based on Gibbs sampling, to examine the characteristics of a posteriori probability density function and the marginal distribution of each parameter.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.719-730
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• 2017

Recently, oceanic research has been carried out investigating global scientific interests and the territorial management of national marine jurisdictional waters, including exclusive economic zones (EEZ) and the open seas. To meet the needs of ocean researchers pursuing these - objectives, acquiring advanced research infrastructure, including research vessels, large facilities, and equipment, is a top priority in ocean science. However, ocean science is a similar to space science, and securing resources and state-of-the-art technology can be expensive. Faced with these challenges, our study focused on establishing a strategy for the efficient operation and management of research vessels, attempting to establish benchmarks from foreign examples that can be adapted to suit the target context. The results of this study provide ways to identify operating systems that could increase the efficiency of joint-use research vessels. The different systems examined in this study included a joint-use committee-based management system (JCMS, Type 1), private enterprise entrusted operating system (PEOS, Type 2), institutional investment operating system (IIOS, Type 3), and commissioned executive operating system (CEOS, Type 4). The efficiencies of JCMS, PEOS, IIOS and CEOS were 9.17, 5.82, 11.2 and -1.72 %, respectively. Given the total costs involved, the most affordable operating system was IIOS. JCMS was the most cost-effective system based on a quantitative cost-benefit analysis, but IIOS also had an acceptable cost-benefit balance. An operational committee would be required and regulations and guidelines shoulde be established to employ, JCMS, while a strategy to yield independent revenue would be needed to utilize an IIOS system.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.663-670
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• 2016

This paper introduces the concept of the computer-aided engineering(CAE) design method for a bypass valve in a system that is used for the safe lifting of mineral resources in deep-seabed mining. Although the bypass valve has a simple mechanism, its design is very difficult because of various influencing factors. This equipment, which has a complex design process, should be developed by CAE-based design method. The method can perform the design, design verification, and virtual experiment at the same time. In this study, the CAE-based method for the design of the bypass valve has been developed using fluid dynamics, multi-body dynamics, and optimization method.

• Journal of the Korean earth science society
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• v.37 no.7
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• pp.408-419
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• 2016

To investigate the in-situ sound velocity of sediment in the southwestern part of the East Sea, the laboratory sound velocity was measured using the pulse transmission technique. The sediment sound velocity measured in laboratory was corrected to in-situ sound velocity based on the seafloor temperature, seawater sound velocity, Kim et al. (2004) model, and Hamilton (1980) model. The distribution of the corrected in-situ sound velocity applying Kim et al. (2004) and Hamilton (1980) models reflects the characteristics of sediments of the study area and shows a similar distribution pattern. The correction for in-situ sound velocity was mostly influenced by seafloor temperature. Then, correction of sound velocity using seafloor sediment temperature data should be accomplished for conversion of laboratory data to in-situ sound velocity.

• Economic and Environmental Geology
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• v.44 no.2
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• pp.153-159
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• 2011

A comprehensive mechanistic model has been used to determine the flow pattern for gas-oil two-phase flow in pipes of petroleum production system. Depending on operational parameters, geometrical variables, and physical properties of the two phases, the two phases shows a specific flow patterns. For different parameters of the system, How pattern were compared for wide range of superficial velocities of oil and gas. In a variety of parameters, the inclinational angle and superficial velocities of oil and gas are the most dominant factors in determining the flow patterns for two-phase flow in pipelines. Other parameters such as pipe diameter and fluid properties have a limited effect on the change of flow patterns except for near transition. The mechanistic model is shown to be useful to determine the flow pattern in situations where either an experimental evaluation in a laboratory or reliable correlations are not available.

• Journal of the Korean GEO-environmental Society
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• v.14 no.5
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• pp.49-56
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• 2013

The necessity of exploration in deep sea increases to develop the natural resources. The deep marine sediments, which were recovered from the hydrate occurrence regions during the Ulleung Basin Gas Hydrate Expedition 2 (UBGH2), East Sea, Korea in 2010, are explored to obtain the geotechnical characteristics and strength parameters. The index properties of the specimens including the atterberg limits, specific surface, and particle size distribution are measured and compared with the previous studies. X-ray diffraction, scanning electron microscope, and X-ray energy dispersive spectroscopy are conducted to analyze the clay mineralogy, chemical composition, and microstructure of the sediments. Strength parameters and shear wave velocities are measured with the axial strain by using an instrumented triaxial device. The strength parameters estimated by empirical equations are compared with the experimental results.

• Food Science of Animal Resources
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• v.33 no.2
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• pp.214-220
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• 2013

The effects of different cations on its composition and flavor characteristics of pidan white and yolk produced with duck egg in comparison to its fresh egg were investigated. Mineral content such as calcium, magnesium, sodium and potassium were significantly increased in pidan yolk irrespective of its cations in pickle solution in comparison to the fresh yolk (P<0.05). It confirmed the migration of minerals from the pickling solution to the egg. However, calcium and magnesium was found lower in 0.2% $PbO_2$ treated pidan. Less pidan flavor compounds were generated in pidan white produced with the aid of 0.2% $PbO_2$. It confirmed that binding of lead prevent the maillard reaction in the pidan treated with $PbO_2$. Benzaldehyde, ketones, alcohol and acid found in the pidan white treated with 0.2% $ZnCl_2$ reveals that volatiles are generated most likely from maillard reaction. However, pidan yolk of both 0.2% $PbO_2$ and 0.2% $ZnCl_2$ showed higher generation of volatiles more likely from yolk lipids. Butanal, pentanal, hexanal, and heptanal are of those aldehydes found in 0.2% $ZnCl_2$ treated pidan yolk whereas hexanal is the only aldehyde detected in 0.2% $PbO_2$ treated pidan yolk. Thus, cations in the pickling solution affect the flavor characteristics of pidan white and yolk.

• The Journal of Engineering Geology
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• v.20 no.2
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• pp.191-202
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• 2010

In this study, the relationship between the settlements and the horizontal displacements according to embankment was analyzed at the marine sedimentary grounds for preparation of a site, and then the empirical equations of both the settlement and the horizontal displacement considering the embankment load and the thickness were proposed. To do this, the field and laboratory tests were performed at the improvement section where the pre-loading method was applied, and the field monitoring was performed using various sensors. Based on the results of the tests and monitoring, the ground deposits, soil characteristics and engineering properties were analyzed and the settlements and lateral movements were estimated by the Regression analysis. The ground deposits from the ground surface were composed of reclaimed soils, sedimentary soils and based rocks. The thickness of clay in the sedimentary soils layer was ranged from 3.9 m to 44.5 m. The embankment heights to improve the ground during pre-loading were constructed from 4.7 m to 7.8 m in each section. The settlements during embankment were ranged from 0.959 m to 2.217 m and the lateral movements were ranged from 0.048 m to 0.313 m. As the result of regression analysis, the equations of settlements and horizontal displacements according to embankments may be proposed as $s=0.02h^2+0.11h$ and ${\delta}=0.01e^{0.37h}$, respectively. The proposed empirical equations of the settlements and the horizontal displacements according to embankment on the marine sedimentary ground may be applied to the site where has a similar condition of study area.