• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.411-413
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• 2012

This study has been investigated about hygrothermal environmental effects on the pin-joined carbon/epoxy composites through acoustic emission technique. The specimens were classified as three types for pin loading test : Base (before immersion), RT (room temperature immersion), HT ($75^{\circ}C$ immersion). As a results, the bearing strength of RT specimens was weakly decreased than that of base specimens. The bearing strength of HT specimens was greatly decreased than that of Base and RT specimens due to effects of simultaneous moisture and higher temperature. Also, the results from cumulative hit of acoustic emission indicated that AE events induced by matrix cracks of HT specimens was lower than that of base specimens.

• Journal of the Korea Computer Graphics Society
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• v.22 no.3
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• pp.31-41
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• 2016

This study proposes suitable input processing technique for producing the mobile platform based virtual reality contents. First of all, we produce the mobile platform based virtual reality interactive contents to be used in experiments for improve user's immersion who experience the virtual reality contents, get interests and design the input processing that easily controllable. Then design the input processing technique in two methods, with gamepad that accessibility to mobile and with directly through user's gaze to interface. Through virtual reality based input processing technique that we proposed, we analyse effect of improve user's immersion, cause of get interests and whether provide the convenience or not for controlling contents through experiments. Moreover we verify whether bring negative psychological elements like sickness, fatigue or not.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.6
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• pp.1529-1538
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• 1995

In this study, a liquid sheet type co-axial nozzle has been used to investigate the turbulent atomization characteristics which could result in the experimental data to be used in designing a jet nozzle with high performance. Image processing technique and immersion sampling method were employed to measure droplet size. In atomizing characteristics, droplet size distributions and absolute droplet sizes, SMD(Sauter Mean Diameter) have been investigated in the wide ranges of flow field depending upon the air-water mass ratios. And the comparisons between the present data and the semi-empirical curves have been conducted semi-empirical correlation for SMD has been derived in the present analysis.

• Journal of the Korean Society of Visualization
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• v.11 no.2
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• pp.18-26
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• 2013

An accurate and reliable performance evaluation technique is indispensable for the development of marine antifouling coatings. The existing standard practice is however, based on the visual observation of biofouling settlement area, which is prone to the subjective judgment of the inspector. In spite of the above mentioned importance, a systematic and objective fouling evaluation technique has not yet been introduced. In this study, a novel quantitative antifouling performance evaluation method for marine antifouling paints is devised based on the image analysis of panel immersion test results. The present image analysis method is to quantify settlement area for each fouling category by distinctive color. The fouling categories are set as unfouled, biofilm, green algae, brown algae, calcareous animal and spongy animal with specific HSL (Hue, Saturation, Lightness) color ranges. In order to assess the effectiveness of the proposed method, static immersion tests for three antifouling coatings were undertaken for two years.

• Journal of the Korean Society for Nondestructive Testing
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• v.28 no.6
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• pp.519-523
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• 2008

Poisson's ratio is one of elastic constants of elastic solids. However, it has not attracted attention due to its narrow range and difficult measurement. Transverse wave velocity as well as longitudinal wave velocity should be measured for nondestructive measurement of Poisson's ratio. Hard couplant for transverse wave prevents transducer from scanning over specimen. In the present work, a novel measurement of Poisson's ratio distribution was proposed. Immersion method was employed for the scanning over the specimen. Echo signals of normal beam longitudinal wave were collected. Transverse wave modes generated by mode conversion were identified. From transit time of longitudinal and transverse waves, Poisson's ratio can be determined without information of specimen thickness. This technique was demonstrated for aluminum and steel specimens.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.392-393
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• 2022

In relation to the creation of an avatar that will become the main character in the metaverse environment, we design a system that automatically determines the shape of the avatar according to the situation and location by adjusting the details between immersion and privacy. In this study, as a way to control immersion in various virtual environments of the metaverse environment, we derive the hypothesis that immersion is determined by how detailed the original object is expressed. We conduct research that can adaptively control the expression information of avatars.

• Proceedings of the Optical Society of Korea Conference
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• 2005.02a
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• pp.198-199
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• 2005

• Food Science of Animal Resources
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• v.34 no.1
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• pp.115-121
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• 2014

This study explored the effects of water or brine (2% NaCl, w/v) immersion thawing combined with ultrasound treatment (40 kHz, 150 W) on the quality characteristics of pork. Ultrasound treatment of pork was conducted in two cold media (at $4^{\circ}C$), water and 2% (w/v) brine, respectively. Because the ultrasound treatment caused temperature increase in the media from $4^{\circ}C$ to $16^{\circ}C$, the qualities of pork thawed by ultrasound were compared with those thawed by immersion either in water or brine where the temperature was being maintained at either $4^{\circ}C$ (low temperature control) or $17^{\circ}C$ (high temperature control). The ultrasound treatment resulted in rapid thawing of pork where the thawing rate was similar to those thawed in the $17^{\circ}C$ media. For quality characteristics, ultrasound-treated pork in brine had an advantage of less cooking losses when comparing to the control. In particular, ultrasound treatment in brine exhibited the lowest shear force (or highest tenderness) among the freezing/thawing treatments. Although the ultrasound processing in brine caused discoloration of the pork, this thawing technique had potential to be applied as a commercial thawing technology for frozen foods.

• Fisheries and Aquatic Sciences
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• v.26 no.1
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• pp.48-57
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• 2023

One of the ways to increase the production for aquaculture is through the cultivation of monosexuals by ensuring genital reversal from which energy for reproduction is diverted towards growth. Masculinization has been identified as one of the most prominent techniques, where sex development was directed from female to male. This approach only altered the phenotype and not the genotype. The red claw crayfish (Cherax quadricarinatus) was a relatively new commercial commodity, and the males were known to grow faster than females. Hence, it was proposed to use monocultures comprising an all-male population to increase yield using steroid hormone, synthetic 17α-methyltestosterone. However, this technique generated residues that detrimentally affect human health, the environment, and cultivated organisms. Therefore, finding new safe natural steroid sources was essential, and one of which is exploring of natural hormones extracted from the viscera of sea cucumbers (Holothuria scabra Jaeger). This study focused on the determination of male formation and testosterone levels among juvenile crayfish, after immersing in sea cucumber steroid extract (SCSE). A completely random design with factorial was used with two variables, encompassing the varied doses (0, 2, 4 mg/L, 2 mg/L 17α-methyl testosterone as control group) and immersion times of 18 and 30 h. The result showed the dose-dependent ability of SCSE increase the male genital formation and promote the testosterone level of juvenile crayfish. In addition, the testosterone was influenced by dose and immersion duration time, with the highest level of testosterone observed in treatments of 4 mg/L SCSE with 30 h immersion was 0.248 ng/mL, while the male percentage was 77%. In conclusion, the combination of dose and immersion time significantly affected growth and testosterone levels.

• Composites Research
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• v.21 no.3
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• pp.1-8
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• 2008

The main objective of this study is to investigate the effect of salt water on the mechanical properties of a carbon-epoxy composite material. Specimens were made of a carbon-epoxy composite USN125 and tested under inplane tension and shear after 0, 0.5, 1, 2, 3, 6, 9, and 12 months immersion in 3.5% salt water. Waterproof painting and acceleration technique were not applied. The tensile strengths and moduli in fiber and matrix directions did not show any remarkable degradation until 12 months immersion. In contrast to the tensile properties, shear strength and modulus started to degrade from the early stage of the immersion time and gradually decreased to 36% and 46% of dry values, respectively, after 12 months immersion.