• Journal of the Korean Society for Marine Environment & Energy
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• v.2 no.1
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• pp.102-112
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• 1999

The purpose of this study is to evaluate the effects of design criteria and environmental conditions of the site of created tidal flats on the structure and function of man-made ecosystem. Seven constructed tidal flats and three natural tidal flats were studied taking the difference in the location (wave height and tidal current), inflow of river water, slope of tidal flat and age after the construction completed into consideration. Parameters studied were physico-chemical and biological characteristics of soils and rate of respiration. The natural tidal flats had higher contents of silt, nitrogen and organic matter compared with the constructed ones. The natural ones had reductive zone below 2cm, whereas the constructed ones had aerobic zone from the surface to below 20cm. The bacterial population in the soil of the constructed tidal flats was one to two orders of magnitude lower than that in the natural ones. Both biomass of macrobenthos and microbial respiration rate, however, were not different significantly between the natural and the constructed tidal flats. There was an exceptional constructed tidal flat with similar physico-chemical and biological characteristics to the natural ones. It is most probable that sufficient conditions to have similar tidal flats to natural ones are the location in enclosed bay or calm coastal area. Thus, to make man-made tidal flats with the same characteristics as those in natural ones, man-made tidal flats should be designed and/or located to enhance the accumulation of silt on tidal flat. It is important to select a place having low water motion for construction of tidal flat.

• Journal of Korean Tunnelling and Underground Space Association
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• v.9 no.4
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• pp.403-413
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• 2007

As rock bolts become one of the main support systems in tunnels and underground structures, the integrity of the rock bolts affects the safety of these types of structures. The purpose of this study is the evaluation of rock bolt integrity using Fourier and wavelet transforms of the guided ultrasonic waves. After five rock bolt specimens with various defect ratios are embedded into a large scale concrete block, guided waves are generated by a PZT (lead zirconate titanate) element and measured by an acoustic emission (AE) sensor. The captured signals are analyzed in the frequency domain using the Fourier transform, and in the time-frequency domain using the wavelet transform based on a Gabor wavelet. The spectrum obtained from the Fourier transform shows that a portion of high frequency contents increases with increase in the defect ratio. Peak values in the time-frequency domain represent the interval of travel time of each echo. The energy velocities of the guided waves increase with the defect ratio. This study shows that the spectrum ratio and the energy velocity may be indicators fur the evaluation of rock bolt integrity.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.4
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• pp.434-444
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• 1994

Physical and acoustic properties of sediment core samples recovered from the Kwangyang Bay, the Yeosu Sound, and the inner shelf of central South Sea, Korea were investigated. Compressional wave velocity, density, porosity, and shear strength were measured at 10cm interval's along the core depth. Sediment texture(grain size, sand, silt, and clay contents) were also measured and correlated with the physical properties(density, porosity, and shear strength). The physical and acoustic properties of the sediment changed gradually from the Kwangyang Bay to the shelf area in accordance with the distance from the input source of the terrigenous sediment. The Yeosu Sound acted as a route of sediment transport from the estuary(the Seomjin River) to the shelf and vice versa. The physical and acoustic properties of the Yeosu Sound sediment conformed to an intermediate stage between river mouth and shelf areas. These results can be utilized to trace the influence of the Seomjin River on the so-called mud belt of Korea.

• Food Science and Preservation
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• v.14 no.6
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• pp.722-726
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• 2007

Extracting and analytical conditions of curcumin, and removal of bitterness substance from Curcuma longa L. were investigated. Absorption maxima was shown to be 424 nm at methanol solvent. Optimal conditions for analysis of curcumin was Zorbax eclipse $C_{18}$ column ; mobile phase, 75% MeOH ; flow rate, 0.8 mL/min ; wave length, UV 424 nm. Curcumin component was analyzed to be the highest content in methanol extract. In all samples, extraction yield by heating was shown to be effective as compared to room temperature. Curcumin contents of methanol and ethanol extracts in extraction of room temperature were 14.4 and 14.2 times higher than that of water extract, respectively. Two hot solvent extracts has a high curcumin content being 150 mg% as compared to room temperature. Extracting time was an effective condition when it was extracted for 60 minutes for elevating the curcumin content of water and methanol extracts. Bitter substance (BS) was markedly decreased in water extract by heat treatment of above $80^{\circ}C$. BS was weak in $121^{\circ}C$ treatment than in room temperature and it was however strong in $100^{\circ}C$ treatment. RT and $70^{\circ}C$ heat treatment were not different in BS intensity.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.59-63
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• 2008

Purpose: The purpose of this study is to understand a relation of water content measurement with two different method, water removal method and dry method. Methods: 72 hydrogel contact lens containing various water content (ranged from 47% to 58%) were measured by the gravimetric method at 20$^{\circ}C$and 21% of the humidity. We weighed the dried test specimen at room temperature for 30 min after cooling. Results: In dry blotting method, the water content was measured to 47.43${\pm}$8.48%. The water contents was measured to 48.15${\pm}$8.36% with wet blotting condition. It was found that wet blotting method showed the higher water content of about 7% than dry blotting method. In water content with two dry methods, each of results was measured by 47.89${\pm}$8.06% and 49.56${\pm}$7.06%. In case of microwave method, the water content was measured significantly higher water content of about 1.67% than vacuum oven method. However, no statistical difference was found (p>0.05). Conclusions: In water removal method (Dry blotting method and Wet blotting method) to weigh hydrated test specimen, wet blotting method showed significantly higher water content than dry blotting method. Also in case of dry methods (vacuum oven and microwave) to weigh dry test specimen, water content of microwave method showed higher water content than vacuum oven method, but it should be noted that microwave oven method must be used carefully to measure accurateness on the specimen position and wave power.

• Korean Journal of Culture and Social Issue
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• v.28 no.3
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• pp.331-352
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• 2022

This study used a latent growth curve models(LGCM) to examine longitudinal changes in youth's game usage, self-control and the longitudinal mediation effect of adaptive game use in the relationship between game usage and self-control. A four-year longitudinal data of 863 adolescents from the Game User Panel Survey, provided through participation in the 2019 Game User Panel Research Conference hosted by the Korea Creative Contents Agency, was used to verify the longitudinal mediation effect of adaptive game use. SPSS 21 was used to verify the normality of variables from each wave, and to conduct correlation analysis. Mplus 6.12 was used to verify the longitudinal mediation effect. The results are as follows. First, game usage, self-control and adaptive game yielded linear temporal growth. Second, latent growth curve models showed that the direct effect of game usage on self-control was insignificant, but game usage had a significant indirect effect on self-control through adaptive game use. Continuous adaptive gaming increased self-control. Third, sobel test results showed that both the initial value and change rate of adaptive game use had a full-mediation effect, confirming the longitudinal mediation effect. This study verified the longitudinal change of self-control affected by change in game usage and adaptive game use.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.5
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• pp.488-496
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• 2023

Ship and bridge structures are a type of long box-shaped structure, and resistance to vertical bending moment is a key factor in their structural design. In particular, because box girders are repeatedly exposed to irregular wave loads for a long time, the continuous collapse behavior of structural members must be accurately predicted. In this study, plastic collapse behavior, including buckling according to load changes of the box girder receiving pure bending moments, was analyzed using a numerical analysis method. The analysis targets were selected as three box girders used in the Gordo experiment. The cause of the difference was considered by comparing the results of the structural strength experiment with those of non-linear finite element analysis. This study proposed a combination of the entire and local sagging shape to reflect the effect of the initial sagging caused by welding heat that is inevitably used to manufacture carbon steel materials. The procedures reviewed in the study and the contents of the initial sagging configuration can be used as a good guide for analyzing the final strength of similar structures in the future.

• Journal of International Area Studies (JIAS)
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• v.16 no.2
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• pp.73-94
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• 2012

Recently, Japanese cultural contents are being evaluated as a worldwide content. Among them, the animation takes an overwhelming place in the world market as a Japanese representative content. We need to understand that Japanese animation is being recognized world wide, because Japanese culture was grafted in to and it's very important to apply that to our situation. Cultural content to dominate the world has a fundamentally characteristics derived from regional culture. Cultural content includes elements of particular culture prototype. To investigate into cultural content that has globally used and is valuable, in-depth and systematic research for local (country) culture prototype showed be carried out. Our research aim to provide basic data so Korean animation can be developed as axis of Korean Wave. This compares and analyzes the Culture prototype from Korea and Japanese modern civilized media animation. Specifically for the animation shown in the culture prototype, we aim to - Analyze the content of culture prototype shown in Korea's animation: 'Hopi and Chadol Bawi', 'Heung-Bu and Nol-Bu', 'A Admiral's Diary', and 'Oseam'. - Analyze the content of culture prototype shown in Japan's animation: 'Genji', 'The Spiriting away of Sen and Chihiro', 'The Princess Mononoke', and 'Raccoon War Pom Poko'. - Compare and analyze the content of culture prototype depending on classifying criteria shown between Korea and Japan. We finally want to provide the basic data to develop the creation material for the global animation content based on these two countries throughout this research.

• Korean Journal of Agricultural Science
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• v.2 no.2
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• pp.451-462
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• 1975

The qualities of the grape wines brewed with the varieties of Steuben, Muscat Bailey A, Merlot, Campbell Early and Alden were compared, and studied the mashing methods of the wine with a variety of Muscat Bailey A. and then investigated the aging effects of ultrasonic wave and the baking treatments on the new wines. The results obtained were as follows. 1. Extracts of the new wines brewed with the varieties of Steuben and Alden were 2.55 and 1.88 per cent respectively and the color densities of the wines with Merlot and Alden were 3.5 and 1.05 (optical density) respectively, and the other contents were not significantly different beween varieties. On the Otherhand, the results of sensory test showed that the order of favorite was the wines brewed with Steuben, Muscat Bailey A, Merlot, Campbell Early and Alden. 2. The effect of pasteurization ($55^{\circ}C$, 20 min.) on the inhibition of the growth of undesirable microorganism was appeared almost the same degree as the case of sulfiting (100 ppm), and the pasteurized must was more dense in color but slightly turbid than the case of sulfiting. 3. Glucose syrup was in adequate as a materials for supplemental sugar, and the quality of the new wine further fermented the free-run wine added the alcohol to be a constant alcohol content was almost the same as that of control. 4. Baking at $50^{\circ}C$. for 50 days to t he new wine from 0.45 to 0.65 per cent, and color density was also thicken from 2.8 to 3.17 (O. D). 5. Baking at $40^{\circ}C$. for 50days to the new wine brewed with Muscat Bailey A, increased the ester content of the wine from 0.37 to 0.65 per cent and color density was-also thicken from 3. to 4.2 (O.D). 6. Ultrasonic wave (150 watt, 20Kc) treatment for 10 hours to the new wine brewed with Muscat Bailey A, increased the ester content of the wine from 0.37 to 0.47 per cent.

• Smart Media Journal
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• v.9 no.2
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• pp.16-21
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• 2020

Recently, mobile traffic is increasing exponentially as major traffic is transferred to IoT and visual media data in the dissemination of mobile communication terminals and contents use. In order to overcome the limitations of the existing LTE system, 5G mobile communication technology (5G) is a technology that meets 1000 times data traffic capacity, 4G LTE system acceptance, low latency, high energy efficiency, and high cost compared to 4G LTE system. The path loss due to the use of the frequency domain is very high, so it may be difficult to provide a service compared to the existing 4G LTE system. To overcome these shortcomings, various techniques are under study. In this paper, small cell technology is introduced to improve the system performance of 5G mobile communication systems. The performance is analyzed by comparing the results of small cell technology application, macro communication and small cell communication, and the results of the proposed algorithm application for power control. The analysis results show that the use of small cell technology in the 5th generation mobile communication system can significantly reduce the shadow area and reduce the millimeter wave path loss problem.