• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.05a
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• pp.43-47
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• 2003

This paper presents the optimum design of cylindrical shell under external pressure loading. Two kinds of material, AI7075-T6, Ti-6AI-4V, are considered. For each material, the design variable is a thickness of the unstiffened parallel middle body shell, and the state variable, constraint, is hoop stress and the object function is total weight of the cylindrical shell. Optimization is performed by conventional FE Program, ANSYS. In addition, buckling analysis is performed for the middle body of the cylindrical shell. Finally, we calculates the payload of the cylindrical shell to keep neutral buoyancy with optimized thickness in deep-sea applications.

• Journal of Ocean Engineering and Technology
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• v.18 no.4 s.59
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• pp.52-58
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• 2004

A Semi-Autonomous Underwater Vehicle (SAUV), capable of simple work on the seabed, is under development in KRISO-KORDI. This SAUV pressure vessel is composed of fiberglass reinforced plastic (FRP), and is also manufactured to carry electronic equipment. The objective of this paper is to describe the safety check for the pressure vessel. This is achieved fly conducting structural analysis and testing in a pressure tank. Strain and stress test results, under unit load, are obtained fly using ANSYS in linear structural analysis. Local buckling analysis are performed with NASTRAN at the middle oj the cylindrical hull. The first test, using linear structural analysis, is unsuccessful, as buckling occurred. During the second test, linear structural analysis, combined with local buckling analysis, is conducted. There is no buckling up to 250 m when both ANSYS and NASTRAN are used.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2009.06a
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• pp.5-6
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• 2009

The influence of different appendage shape on the characteristics of hydrodynamic forces on Manta-Type Unmanned Undersea Test Vehicle(MUUTV) was discussed experimentally. Fuselage only MUUTV model and two types of MUUTV model with different appendage geometries were considered as subject of discussion Oblique tow experiment was carried out in circulating water channel with three MUUTV models. A point of difference in hydrodynamic force characteristics among three models was compared and discussed. Furthermore, the linear hydrodynamic derivatives obtained from model experiment were compared with theoretical calculation results from slender body theory, added mass theory and ete. Based on the hydrodynamic force characteristics, motion stability of two types of MUUTV model with different appendage geometries was discussed and compared each other. Through the above analysis, the more suitable shape of appendage geometry was made clear.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.7
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• pp.1202-1208
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• 2008

This paper represents the multiple sensor fusion algorithm for the deep-sea unmanned underwater vehicles (UUV), composed of a remotely operated vehicle (ROV) 'Hemire' and a depressor 'Henuvy'. The performance of underwater positioning system usually highly depend on that of acoustic sensors such as ultra short base line(USBL), long base line(LBL) and altimeter. A practical sensor fusion algorithm is proposed in the sense of a moving window concept. The performance of the proposed algorithm can be observed by applying the algorithm to the Hemire sea trial data which was measured at the East Sea.

• Journal of Ocean Engineering and Technology
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• v.32 no.6
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• pp.511-517
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• 2018

This paper proposes a vision-based underwater laser scanner with separate structures for an underwater camera and a line laser projector. Because the two devices can be adaptively placed regardless of the features of the unmanned underwater vehicle (UUV), the scanner has significant advantages in relation to its availability and flexibility. Position calibration between the underwater camera and laser projector guarantees a 3D measuring performance with high accuracy. To verify the proposed underwater laser scanner, a test-bed system was manufactured, which consisted of the laser projector, camera, Pan&Tilt, and Attitude and Heading Reference System (AHRS). A camera-laser calibration test and simple 3D reconstruction test were performed in a water tank and the experimental results are reported.

• Geophysics and Geophysical Exploration
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• v.14 no.1
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• pp.80-87
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• 2011

Autonomous underwater vehicles (AUVs) present the important advantage of being able to approach the seafloor more closely than surface vessel surveys can. To collect bathymetric data, bottom material information, and sub-surface images, multibeam echosounder, sidescan sonar (SSS) and subbottom profiler (SBP) equipment mounted on an AUV are powerful tools. The 3000m class AUV URASHIMA was developed by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC). After finishing the engineering development and examination phase of a fuel-cell system used for the vehicle's power supply system, a renovated lithium-ion battery power system was installed in URASHIMA. The AUV was redeployed from its prior engineering tasks to scientific use. Various scientific instruments were loaded on the vehicle, and experimental dives for science-oriented missions conducted from 2006. During the experimental cruise of 2007, high-resolution acoustic images were obtained by SSS and SBP on the URASHIMA around the northern Kumano Basin off Japan's Kii Peninsula. The map of backscatter intensity data revealed many debris objects, and SBP images revealed the subsurface structure around the north-eastern end of our study area. These features suggest a structure related to the formation of the latest submarine fan. However, a strong reflection layer exists below ~20 ms below the seafloor in the south-western area, which we interpret as a denudation feature, now covered with younger surface sediments. We continue to improve the vehicle's performance, and expect that many fruitful results will be obtained using URASHIMA.

• Journal of Sericultural and Entomological Science
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• v.23 no.2
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• pp.11-36
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• 1982

Forty-nine plant species as additives to silkworm artificial diet and 5 species as cellulose sources for artificial diet were screened for their economic values as feed-resources for the silkworm. Feeding response to artificial diet was tested on 82 silkworm strains. The effect of rearing conditions on feeding response and enzyme activities in the silkworm was investigated. The results were summarized as follows. 1. Seven species out of 49, Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Alnus japonica Stendel, Trifolium repens L, Prunus serrulata Lindley. Var, Glycine max L increased feeding response, compared with the basic formula of artificial diet. 2. The economic values of Vigna sinensis ENDL, Ipomoea vatatas Lamarck, Cyperus anuricus Var. Laxus, Ainus japonica Stendel, Cassia tera L, Erigeron canedensis L as feed-resources for artificiale diet were recognized, through feeding experiment during the entire larval stage. 3. Mulberry cellulose showed the best results in rearing and cocoon characteristics. 4. The extent of feeding response varied according to strains and varieties. Varieties in japanese strains showed higher feeding response than those in chinese and european varieties, with considerable variations among a varieties in strains. 5. The begining of 4th instar seems to be a proper time to convert from mulberry to artificial diet, or artificial diet to mulberry, however the middle of 3rd instar seems acceptable. 6. The optimum temperature for artificial diet rearing is 30$^{\circ}C$ during the period of 1st-3rd instar and 28$^{\circ}C$ for 4th-5th instar. 7. Electrophoretic isozyme patterns of esterase and acid phosphatase on agarose gel, as affected by strain. rearing temperature and feed-resources, were observed as follow. (1) Isozyme patterns of mid-gut esterase varied, depending on instar. One or two more isozyme bands were observed in the larvae than feed on the mulberry fed for the artificial diet. (2) A strain, chinese-15 with a higher feeding response, had 1∼2 more bands than chinese-60 with a lower feeding response. (3) Five bands of mid-gut esterase in 3rd and 4th instar larvae reared at 28$^{\circ}C$. and 4 for 3rd instar and 6∼7 for 4th instar larvae at 35$^{\circ}C$ were observed. (4) No similar esterase bands could be found among mid-gut, blood and silkgland. There are five esterase bands in the midgut, one in blood and three in silkgland. (5) There was rather small digerence in acid phosphatase types of mid-gut and blood according to varieties and rearing temperature. No active band was shown in silkgland. In midgut, there was one acid phosphatase band at 3rd instar, two at 4th instar and three at 5th instar. In blood, one active band at 3rd or 4th instar and three bands at 5th inster wire detected.

• Journal of Life Science
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• v.30 no.2
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• pp.147-155
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• 2020

In this study, the antioxidant and cytotoxic effects and the flavonoid contents of leaf extracts from Stachys sieboldii Miq. and Lycopus lucidus Turcz. were compared. The flavonoid contents of the acetone + methylene chloride (A+M) and methanol (MeOH) extracts of L. lucidus Turcz. leaves were 55.7 and 233.2 mg/g, respectively. In a DPPH assay, A+M and MeOH extracts from L. lucidus Turcz leaves had a greater scavenging effect than those of S. sieboldii Miq. leaves (p<0.05). In an ABTS assay, MeOH extracts from S. sieboldii Miq. and L. lucidus Turcz (0.5 mg/ml concentration) leaves had scavenging effects of 85% and 91%, respectively (p<0.05), suggesting that both of the MeOH extracts had greater scavenging effects than both A+M extracts. In a 120 min ROS production assay, all tested extracts decreased the cellular ROS production induced by H₂O₂ compared to that produced by exposure to the extract-free control. The MeOH extract from L. lucidus Turcz leaves had a greater inhibitory effect on cellular ROS production (p<0.05). Treatment with A+M and MeOH extracts from both S. sieboldii Miq. and L. lucidus Turcz. leaves showed a dose-dependent increased cytotoxicity against the growth of AGS, HT-29 cancer cells, and HT-1080 (p<0.05). Both A+M extracts had a greater inhibitory effect on the growth of all cancer cells than both MeOH extracts. These results suggest that the MeOH extract of L. lucidus Turcz. leaves is effective in scavenging free radicals and inhibiting cellular oxidation, while the A+M extract inhibits proliferation of three types of cancer cell.

• Food Science and Preservation
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• v.24 no.5
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• pp.615-622
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• 2017

This study investigated the antioxidant and antidiabetic activities of Stachys sieboldii Miq. extracts by solvents (water, ethanol, butanol, chloroform, and hexane). The contents of total polyphenols (7.18-37.25 mg/g) and flavonoids (0.21-5.21 mg/g) in extracts from Stachys sieboldii Miq. showed a significant difference dependent on the extraction solvents, butanol > ethanol > water > chloroform > hexane. Antioxidant activities by DPPH and ABTS radical scavenging were increased in a dose-dependent manner. These activity trends associated with the extraction solvent were different at each concentration, but resembled phenolic compound contents trend, generally. FRAP value increased in a dose-dependent manner, but there was a difference in radical scavenging activities when comparing between extraction solvents by butanol > ethanol > hexane > chloroform > water on all concentrations. The trend of ${\alpha}$-amylase inhibition of extracts from $1,000{\mu}g/mL$ to $2,000{\mu}g/mL$ was not affected as enzyme activity is promoted and not inhibited. The inhibition of ${\alpha}$-glucosidase was increased in a dose-dependent manner without water extracts, the activity on hexane extracts was higher than others per the extraction solvent. ${\alpha}$-Glucosidase inhibition of hexane extracts showed 57.76% at $250{\mu}g/mL$, which is 2.8 times higher than the second highest chloroform extract (20.65%). From these results, we presume that the active ingredients of Stachys sieboldii Miq. is different according to the extraction solvent and also the activity is different by these major functional groups.

• Journal of Life Science
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• v.34 no.4
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• pp.245-253
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• 2024

We investigated to analyze total flavonoid content and fatty acid composition of Stachys sieboldii Miq root. In order to determine antioxidant and anti-inflammatory effects of fractions from S. sieboldii Miq. root, we conducted 1.1-Diphenyl-2-picryhydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenothiazoline-6-sulfonic acid) diammonium salt radical cation (ABTS) assays for antioxidant and measured nitric oxide (NO) production induced by lipopolysaccharide (LPS) in RAW 264.7 cells. In addition, we examined an inhibitory effect of fractions from S. sieboldii Miq. root on smad signaling induced by transforming growth factor (TGF) β. Among the fractions, n-butanol (n-BuOH) fraction showed the highest flavonoid content (16.67 mg/g), followed by n-Hexane, water and 85% aqueous methanol (85% aq. MeOH) fractions. The fatty acid composition of S. sieboldii Miq. root was in the following order : n-6 fatty acids (54.3%) > n-3 fatty acids (21.2%) > saturated fatty acids (19.7%) > n-9 fatty acids (3.6%). As a result of the antioxidant efficacy, the DPPH and ABTS assays showed that n-BuOH fraction had higher scavenging activity compared to other fractions. Inhibitory effect on NO production showed that all fractions decreased LPS-induced NO production, indicating an anti-inflammatory activity of S. sieboldii Miq. root. 85% aq. MeOH and water fractions showed a higher efficacy in inhibiting transforming growth factor (TGF) β induced smad signaling. From the results, it suggests that food processing products using S. sieboldii Miq. root will be developed as a functional food for promoting health.