• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.65-74
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• 2008

The small and medium sized dams have the fill dam type of a lot of occasions, which are often weak in cases of major floods. For this reason, although a countermeasure is in great need, due to the importance of the facilities and financial situations, no direct safety measures have been taken. In this study, in order to minimize construction expenditure for practical safety measures in cases of major floods, the overflow section of spillway has been analyzed focusing on how the overflow capacity will increase in the case of partially rebuilding a part of the overflow section of spillway favorable for hydraulic conditions. The Labyrinth weir and movable weir was chosen for reconstruction models of the overflow section. Moreover, for analyzing the after-effects of the reconstruction, a small scale dam was temporarily chosen for various experiments such as the hydraulic model testing and the three dimension numerical evaluation through the use of Flow-3D.

• The Journal of the Korea Contents Association
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• v.11 no.7
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• pp.192-209
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• 2011

This study looked into coping strategies of local terrestrial broadcasting companies in the media market, since the introduction of comprehensive programming channels was confirmed. Local terrestrial broadcasting companies vulnerable to market competitiveness are driven more out to the difficulty of survival in a limited advertising market with the advent of comprehensive programming channel. and Local terrestrial broadcasting receive discriminative application than comprehensive programming channel. They have reverse discrimination in must-carry, broadcasting area, programming regulation, advertisement regulation, broadcasting development fund. Hence, Local terrestrial broadcasting needs diverse countermeasures at difficult media circumstances. Above all, Competitive content reinforcement is desperately needed. That's why content distribution structure needs diversification. And, It is necessary for local terrestrial broadcasting companies to diversify the content distribution system. As a way to expand distribution structure of local broadcasting, the introduction of local programming regulations for total amount will be highlighted in the nationwide network program. The mandatory policy that programs produced by local terrestrial broadcasting companies will be broadcast regularly in prime time through a nationwide network is an example. In addition to developing high content independently, 2nd Multiple channels of distribution is needed. It has to be supplied to various platforms including local broadcasting, SO and etc. In addition, it is necessary to activate regional co-production program between local terrestrial broadcasting companies and regions. Time rate between central stations and local terrestrial broadcasting companies must be distributed practically. And also, local terrestrial broadcasting companies in addition to ad revenue model to themselves and their own businesses by expanding the sponsorship to strengthen the competitiveness will have to nurture self-sustaining. Moreover they must have enlarge economy of scale through widen of broadcasting area.

• Journal of Navigation and Port Research
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• v.35 no.3
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• pp.197-204
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• 2011

The authors adopt the Unmanned Undersea Vehicle(UUV), the shape of which is like a manta. They call here it Manta UUV. Manta UUV has been designed from the similar concept of the UUV called Manta Test Vehicle(MTV), which was originally built by the Naval Undersea Warfare Center of USA(Lisiewicz and French, 2000; Simalis et al., 2001; U.S. Navy, 2004). The present study deals with the effect of Reynolds numbers on hydrodynamic forces acting on Manta UUV at large angles of attack. The large angles of attack cover the whole range of 0 to ${\pm}$ 180 degrees in horizontal plane and in vertical plane respectively. Static test at large attack angles has been carried out with two Manta UUV models in circulating water channel. The authors assume that the experimental results of hydrodynamic forces (lateral force, yaw moment, vertical force and pitch moment) are analyzed into two components, which are lift force component and cross-flow drag component. First of all, Based on two dimensional cross-flow drag coefficient at 90 degrees of attack angle, the cross-flow drag component at whole range of attack angles is calculated. Then the remainder is assumed to be the lift force component. The only cross-flow drag component is assumed to be subject to Reynolds number.entstly the authors suggest the methodology to predict hydrodynamic derivertives acting on the full-scale Manta UUV.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.101-107
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• 2007

This study was carried out to examine the in vitro effects of alginate (LVA) which is low viscosity alginic acid, on collagen type II synthesis of chondrocytes and the in vivo effect, orally administered, on cartilage degradation. Rabbit articular chondrocytes were cultured in 35 mm dishes and then LVA was treated. The effects of LVA of various viscosity (86.5 cP(LVA1),45.4 cP(LVA2), 21.2 cP(LVA3) and 9.6 cP(LVA4)) and various concentration (50, 100, 200 ${\mu}$g/ml of LVA4) on chondrocytes were determined by western blotting assay for the detection of collagen type II production. In western blotting assay, collagen type II production in chondrocytes were 1.00 in control,0.95 in LVA1, 1.41 in LVA2, 1.57 in LVA3 and 1.58 in LVA4. Collagen type II production of various concentration of LVA4 were 1.00 in control, 1.24 in 50 ${\mu}$g/ml of LVA4, 1.52 in 100 ${\mu}$g/ml of LVA4 and 1.86 in 200 ${\mu}$g/ml of LVA4. Osteoarthritis (OA) was induced in 24 rabbits by unilateral anterior cruciate ligament transection (ACLT) and randomly divided into 6 groups. The experimental group was given oral administration of 0.5 ml/kg of saline(control), 12.5 mg/kg of LVA (A12.5), 25 mg/kg of LVA (A25), 50 mg/kg of LVA (A5O), 75 mg/kg of LVA (A75) and 20 mg/kg of aceclofenac (AC) for 6 weeks after ACLT. All knees were harvested at 6 weeks after surgery and cartilage degradation was evaluated. Cartilage degradation in the control group was significantly more severe than that in the A25, A5O and A75 groups but AC group had no significant changes on the macroscopic grading scale.

• Journal of Astronomy and Space Sciences
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• v.23 no.4
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• pp.385-396
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• 2006

The International GNSS Service (IGS) has prepared for a transition from the relative phase conte. variation (PCV) to the absolute PCV, because the terrestrial scale problem of the absolute PCV was resolved by estimating the PCV of the GPS satellites. Thus, the GPS data will be processed by using the absolute PCV which will be an IGS standard model in the near future. It is necessary to compare and analyze the results between the relative PCV and the absolute PCV for the establishment of the reliable processing strategy. This research analyzes the effect caused by the absolute PCV via the GPS network data processing. First, the four IGS stations, Daejeon, Suwon, Beijing and Wuhan, are selected to make longer baselines than 1000km, and processed by using the relative PCV and the absolute PCV to examine the effect of the antenna raydome. Beijing and Wuhan stations of which the length of baselines are longer than 1000km show the average difference of 1.33cm in the vertical component, and 2.97cm when the antenna raydomes are considered. Second, the 7 permanent GPS stations among the total 9 stations, operated by Korea Astronomy and Space Science Institute, are processed by applying the relative PCV and the absolute PCV, and their results are compared and analyzed. An insignificant effect of the absolute PCV is shown in Korea regional network with the average difference of 0.12cm in the vertical component.

• Journal of the Korean Ceramic Society
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• v.42 no.4
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• pp.245-250
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• 2005

ZnO was deposited on sapphire single crystal substrate by an ultrasonic pyrolysis of Zinc Acetate Dehydrate (ZAH) with carrying Ar gas. Through Thermogravimetry-Differential Scanning Calorimetry(TG-DSC), zinc acetate dihydrate was identified to be dissolved into ZnO above $380^{\circ}C$. ZnO deposited at $380-700^{\circ}C$ showed polycrystalline structures with ZnO (101) and ZnO (002) diffraction peaks like bulk ZnO in XRD, and from which c-axis strain ${\Sigma}Z=0.2\%$ and compressive biaxial stress$\sigma=-0.907\;GPa$ was obtained for the ZnO deposited $400^{\circ}C$. Scanning electron microscope revealed that microstructures of the ZnO were dependent on the deposition temperature. ZnO grown below temperature $600^{\circ}C$ were aggregate consisting of zinc acetate and ZnO particles shaped with nanoblades. On the other hand the grain of the ZnO deposited at $700^{\circ}C$ showed a distorted hexagonal shape and was composed of many ultrafine ZnO powers of 10-25 nm in size. The formation of these ulrafine nm scale ZnO powers was explained by the model of random nucleation mechanism. The optical property of the ZnO was analyzed by the photoluminescence (PL) measurement.

• Journal of Ecology and Environment
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• v.40 no.1
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• pp.55-65
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• 2016

Background: In this article, it was analyzed how snow melting affects the assembly of lichen and moss communities in a small area of the coastal region of Barton Peninsula, which is in maritime Antarctic. In the small area, even though there is a huge gap of difference of the environment between the snow-filled area and snow-melt one, the latter did not have distinctive environmental gradients. Results: Depending on the snow melting time, coverage and species diversity of lichens and mosses tend to increase remarkably. For species with significant changes depending on the snow-covered period, there are Andreaea regularis, crustose lichens, Placopsis contortuplicata, Usnea aurantiaco-atra, and snow algae. In this area, the process of vegetation assembly process has shown the directional development in the order of snow algae${\rightarrow}$crustose, lichen sub-formation${\rightarrow}$fruticose lichen, moss cushion sub-formation (Andreaea sociation)${\rightarrow}$fruticose lichen, and moss cushion sub-formation (Usnea sociation), according to the order of snow melting. These directional development stages are shown in gradual change in small area with the snow melting phenomena. However, in the snow-free area, where water is sufficiently supplied, it is expected that moss carpet sub-formation (Sanionia sociation) will be developed. Vegetation development in the small area with the snow melting phenomena, depending on differences of resistance on snow kill and moisture settled by species in according to the time of snow melting, tolerance model to form community is followed. Conclusions: The research results explain the development of vegetation in the Antarctic tundra and its spatial distribution according to the period for growth of lichens and mosses in the summer time by differences of snow melting in the small area. In the future, if research for the community development process in a large scale will be done, it will be helpful to figure out temporal and spatial dynamic of vegetation in the Antarctic tundra where snow and glaciers melt rapidly due to climatic warming.

• Journal of Environmental Science International
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• v.18 no.6
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• pp.645-654
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• 2009

Lab-scale Electrodialysis(ED) system with different membranes combined with before or after pyroma process were carried out to remove nitrate from two pickling acid wastewater containing high concentrations of $NO_3\;^-$(${\approx}$150,000 mg/L) and F($({\approx}$ 160,000 mg/L) and some heavy metals(Fe, Ti, and Cr). The ED system before Pyroma process(Sample A) was not successful in $NO_3\;^-$ removal due to cation membrane fouling by the heavy metals, whereas, in the ED system after Pyroma process(Sample B), about 98% of nitrate was removed because of relatively low $NO_3\;^-$ concentration (about 30,000 mg/L) and no heavy metals. Mono-selective membranes(CIMS/ACS) in ED system have no selectivity for nitrate compared to divalent-selective membranes(CMX/AMX). The operation time for nitrate removal time decreased with increasing the applied voltage from 10V to 15V with no difference in the nitrate removal rate between both voltages. Nitrate adsorption of a strong-base anion exchange resin of $Cl\;^-$ type was also conducted. The Freundlich model($R^2$ > 0.996) was fitted better than Langmuir mode($R^2$ > 0.984) to the adsorption data. The maximum adsorption capacity ($Q^0$) was 492 mg/g for Sample A and 111 mg/g for Sample B due to the difference in initial nitrate concentrations between the two wastewater samples. In the regeneration of ion exchange resins, the nitrate removal rate in the pickling acid wastewater decreased as the adsorption step was repeated because certain amount of adsorbed $NO_3\;^-$ remained in the resins in spite of several desorption steps for regeneration. In conclusion, the optimum system configuration to treat pickling acid wastewater from stainless-steel industry is the multi-processes of the Pyroma-Electrodialysis-Ion exchange.

• Journal of the Korean earth science society
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• v.33 no.7
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• pp.658-671
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• 2012

This study is to develop teaching materials for the geological fieldwork of Jeokbyeokgang area located in the national park of the Byeonsan-bando National Park, Buangun, Jeonbuk, Korea. The developed teaching materials are used in middle school science to effectively teach the fieldwork of the area. The sedimentary succession of Jeokbyeokgang area in the Cretaceous age, Mesozoic, represents the large-scale and distinctive sedimentary structures on sea cliffs, which are worth developing as teaching materials for the earth science fieldwork. The area of Jeokbyeokgang also comprises various geological structures related to the advanced learning programs as well as those within the curriculum of earth science in middle school level. A five-step fieldwork model was applied to 20 students in middle school earth science. This study quantitatively analyzed students' responses to the process of the fieldwork activity. Results indicated that the fieldwork activity using the developed teaching materials was effective in helping the students to improve their self-directed learning and practical understanding of earth science.

• Journal of the Korean earth science society
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• v.28 no.7
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• pp.747-761
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• 2007

This study is to develop teaching aids and materials for geological fieldwork and to maximize their effects in educating high school students in Korea. The site of geological fieldwork, Kyokpo Chaeseokgang area, is located in Byunsan national park in Jeonbuk Province. The sedimentary succession of Chaeseokgang developed in the era of Cretaceous shows large-scale and distinct sedimentary structures on sea cliffs. In this study, teaching aids and materials of earth science for secondary-level students were developed based on the sedimentary structures of Chaeseokgang. A 5-step teaching model of earth science fieldwork was applied to a group of 13 students, who had been involved in clubs related to earth science in a science high school, using teaching aids and materials developed in this study. The teaching aids and fieldwork-related materials were also presented to a group of 37 students, who did not take fieldwork or fieldwork-related classes during the period of the study. The results of this study showed that the use of fieldwork-related aids and materials was effective in helping the students in both groups improve their self-directed teaming and practical understanding of earth science.