• Ocean Systems Engineering
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• v.6 no.1
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• pp.23-60
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• 2016

The major objective of this study was to develop further understanding of 3D nearshore hydrodynamics under a variety of wave and tidal forcing conditions. The main tool used was a comprehensive 3D numerical model - combining the flow module of Delft3D with the WAVE solver of XBeach - of nearshore hydro- and morphodynamics that can simulate flow, sediment transport, and morphological evolution. Surf-swash zone hydrodynamics were modeled using the 3D Navier-Stokes equations, combined with various turbulence models (${\kappa}-{\varepsilon}$, ${\kappa}-L$, ATM and H-LES). Sediment transport and resulting foreshore profile changes were approximated using different sediment transport relations that consider both bed- and suspended-load transport of non-cohesive sediments. The numerical set-up was tested against field data, with good agreement found. Different numerical experiments under a range of bed characteristics and incident wave and tidal conditions were run to test the model's capability to reproduce 3D flow, wave propagation, sediment transport and morphodynamics in the nearshore at the field scale. The results were interpreted according to existing understanding of surf and swash zone processes. Our numerical experiments confirm that the angle between the crest line of the approaching wave and the shoreline defines the direction and strength of the longshore current, while the longshore current velocity varies across the nearshore zone. The model simulates the undertow, hydraulic cell and rip-current patterns generated by radiation stresses and longshore variability in wave heights. Numerical results show that a non-uniform seabed is crucial for generation of rip currents in the nearshore (when bed slope is uniform, rips are not generated). Increasing the wave height increases the peaks of eddy viscosity and TKE (turbulent kinetic energy), while increasing the tidal amplitude reduces these peaks. Wave and tide interaction has most striking effects on the foreshore profile with the formation of the intertidal bar. High values of eddy viscosity, TKE and wave set-up are spread offshore for coarser grain sizes. Beach profile steepness modifies the nearshore circulation pattern, significantly enhancing the vertical component of the flow. The local recirculation within the longshore current in the inshore region causes a transient offshore shift and strengthening of the longshore current. Overall, the analysis shows that, with reasonable hypotheses, it is possible to simulate the nearshore hydrodynamics subjected to oceanic forcing, consistent with existing understanding of this area. Part II of this work presents 3D nearshore morphodynamics induced by the tides and waves.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.2
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• pp.151-158
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• 2009

We found that silymarin exhibited the inhibitory effect on melanogenesis in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab. Silymarin is a standardized extract obtained from the dried seeds of milk thistle (Silybum marianum Gaertn.). Silymarin significantly prevented melanin production in a dose-dependent manner with an $IC_{50}$ value of 28.2 ${\mu}g/mL$ without effects on cell viability. Also, silymarin inhibited tyrosinase activity in melanocyte, while it did not affect the catalytic activity of cell-free tyrosinase. Furthermore, Western blot analysis indicated that silymarin decreased the expression of tyrosinase protein. Silybin A/B and isosilybin A/B were also able to inhibit melanin production and tyrosinase expression in protein level. Double blind study on the clinical efficacy of a cream containing 2 % silymarin showed that silymarin have a significant skin whitening effect. Therefore, this study suggests that silymarin may be useful as a natural skin whitening agent.

• Journal of the Korean Magnetics Society
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• v.13 no.4
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• pp.155-159
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• 2003

We report on the annealing effect and ferromagnetic characteristics of Zn$_{0.7}$Mn$_{0.3}$O film prepared by sol-gel method on the silicon (100) substrate using field emission-scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), X-ray diffractometry (XRD) and superconducting quantum interference device (SQUID) magnetometry. Magnetic measurements show thatZn$_{0.7}$Mn$_{0.3}$O films exhibit ferromagnetism at 5 K revealing the coercive field of ∼110 Oe for as grown sample and 360, 1035 Oe for samples annealed at 700, 800 $^{\circ}C$, respectively. Our experimental evidence suggests that ferromagnetic precipitates of a manganese oxide may be responsible for the observed ferromagnetic behaviors of the film.he film.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.345-357
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• 2005

Prostaglandin plays a significant role in the local control of bone metabolism associated with periodontal disease. ${\Delta}^{12}-PGJ_2$ is a natural $PGD_2$ metabolite that is formed in vivo in the presence of plasma. It is known for ${\Delta}^{12}-PGJ_2$ to stimulate calcification in osteoblastic cells. Bone morphogenetic protein(BMP) stimulated osteoblastic differentiation in various types of cells and greatly enhanced healing of bony defects. The purpose of this study was to evaluate the effect of rhEMP-2 on ${\Delta}^{12}-PGJ_2$ induced osteoblastic differentiation and mineralization in vitro. A human osteosarcoma cells line Saos-2 were cultured. In the test groups, 10-7M of ${\Delta}^{12}-PGJ_2$ or mixture of 10-8M of ${\Delta}^{12}-PGJ_2$ and 100ng/ml of rhBMP-2 or 100ng/ml of rhEMP-2 were added to culture media. After 1 day, 2 days and 4 days of culture period, the cell number was measured. Alkaline phosphatase activity was measure at 3 days. Reverse transcription polymerase chain reaction(RT-PCR) was performed to determine the expression of mRNA of bone matrix protein at 8 hours, 1 day and 7 days. The ability to produce mineralized nodules in rat osteoblasts(MC3T3-E1) was evaluated at 21 days. The results were as follows : 1. rhEMP-2 or mixture of rhBMP-2 and ${\Delta}^{12}-PGJ_2$ inhibited cell proliferation of human osteosarcoma cells. 2. rhEMP-2 or mixture of rhBMP-2 and ${\Delta}^{12}-PGJ_2$ stimulated alkaline phosphatase activity significantly higher than ${\Delta}^{12}-PGJ_2$ alone. 3. rhBMP-2 or mixture of rhEMP-2 and ${\Delta}^{12}-PGJ_2$ stimulated mineralization compared to ${\Delta}^{12}-PGJ_2$ alone. 4. mRNA of alkaline phosphatase, BMP-2, cbfa 1, Type I collagen were detected in the group treated with ${\Delta}^{12}-PGJ_2$/rhBMP-2, rhBMP-2 alone, ${\Delta}^{12}-PGJ_2$ alone. These results show that mixture of ${\Delta}^{12}-PGJ_2$ and rhBMP-2 causes more bone formation than ${\Delta}^{12}-PGJ_2$ alone while the bone formation effects of mixture of ${\Delta}^{12}-PGJ_2$ and rhBMP-2 are less than those of rhBMP-2 alone. Further researches would be necessary to clarify the interactions of these agents.

• Journal of the Korea Society for Simulation
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• v.15 no.2
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• pp.31-39
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• 2006

The visibility graph is a well-known method for efficient path-finding with the minimum search space modelling the game world. The generalized visibility graph is constructed on the expanded obstacle boundaries to eliminate the "wall-hugging" problem which is a major disadvantage of using the visibility graph. The paths generated by the generalized visibility graph are guaranteed to be near optimal and natural-looking. In this paper we propose the method to apply the generalized visibility graph efficiently for game characters who moves among static obstacles between varying start and goal points. Even though the space is minimal once the generalized visibility graph is constructed, the construction itself is time-consuming in checking the intersection between every two links connecting nodes. The idea is that we build the map for static obstacles first and then incorporate start and goal nodes quickly. The incorporation of start and goal nodes is the part that must be executed repeatedly. Therefore we propose to use the rotational plane-sweep algorithm in the computational geometry for incorporating start and goal nodes efficiently. The simulation result shows that the execution time has been improved by 39%-68% according to running times in the game environment with multiple static obstacles.

• Korean Journal of Plant Resources
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• v.27 no.1
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• pp.22-28
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• 2014

In this study, we conducted the anti-HIV-1 enzymes assay in vitro and its active components were predicted by QSAR in silico for the elucidation of action mechanism on anti-HIV of natural resources. The extracts of Gardenia jasminoides var. radicans Makino were tested for their inhibitory effects on the reverse transcriptase (RT), protease and ${\alpha}$-glucosidase. In the enzyme inhibition assay, the methanol extracts of Gardenia jasminoides var. radicans Makino stem showed a strong activity of 32.5% on the enzyme activity to cleave an oligopeptide, resembling one of the cleavage sites in the viral polyprotein which can only be processed by HIV-1 protease. Moreover the methanol extracts of stem exhibited alpha-glucosidase inhibitory activities of 26.1%. The methanol extracts ($100{\mu}g/ml$) of stem showed a weak activity of 13.4% on anti-HIV-1 RT using Enzyme Linked Oligonucleotide Sorbent Assay (ELOSA) method. However, all extracts of leaf and stem didn't exhibit the HIV-1-induced cytopathic effects with IC (inhibitory concentration) of $100{\mu}g/ml$ in HIV-1-infected human T-cell line. From these results, it is suggested that Gardenia jasminoides var. radicans Makino extracts may possibly be involved in the inhibition of reverse transcriptase, protease and alpha-glucosidase but can't vitally concerned with the viral replication in vitro.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.221-227
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• 2005

Apoptosis of Prunus salicina Lindl. cv. Soldam, which possesses hematopoiesis, osteoporosis prevention, and antimutagenic effects, at different growth stages was evaluated. Cytotoxic effect of acetone extracts of immature fruits against various tumor cell lines was higher than that of mature fruits, particularly in hormone-independent human breast cancer, MDA-MB-231 cell line. Immature fruit extract increased expression level of pro-apoptotic protein Bax and reduced that of anti-apoptotic protein Bcl-2, and stimulated caspase-3 activity in MDA-MB-231 cells. Results suggest immature fruit of P. salicina Lindl. cv. soldam to be natural source for development of functional food and medical agents to prevent human breast cancer.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.27 no.6
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• pp.639-647
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• 2009

In line with the rapid settlement of information society, the demand for geospatial information and its applications are dramatically increasing. The Project of National Geographic Information System(NGIS) is actively on going to meet up-to-dateness and accuracy of geospatial data. It is fact that the public interest in environmental issues is increasing than ever in accordance with the restoration of the four major rivers, core project of Green New Deal Policy, and the event of the Ramsar General Meeting. Because the Nakdong River Estuary is a place of great importance in both aspects of wetland and environment conservation, a variety of researches related to this area are progressing. Although artificial developments and natural phenomena are rapidly changing the topography and ecosystem of this area, the effort to build topographic DB for change monitoring is very slow. This study describes a Lidar surveying project over the restored wetland Eulsukdo, the southermost part of the Nakdong River, to establish precise topographic DB throughout producing 3D topographical maps and wetland classification maps. The results of this study will make a large contribution to the systematic maintenance and management for the restored Eulsukdo wetland.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.3
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• pp.12-21
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• 2012

The proximities of Cheonggye creek was a maj or space for the gathering of large populations from the past times and it is also a place containing the joy, anger, sorrow, pleasure and lives of the citizens. The Cheonggye creek which flowed downtown of Seoul throughout many historical events had disappeared into history completely in the modernization process due to the contamination with life sewages and overflow. However, the city authority of Seoul decided to restore it to its shape before covering the creek by means of dismantling the old elevated ways in Cheonggye creek in line with the Large Scale City Movement Project to revive the grey city and to improve the quality of the city landscape in 2002. The cultural space was created by activating the old town sphere in Cheonggye Creek and the amenities of the giant city was improved by the cultural and natural wave created along the creek. In addition, the educational opportunity has been provided to the citizens by means of reviving its historical nature. The design and cultural value of the Cheonggye Plaza were restored for the mean time and the urban environment requested during modem times was established. The Cheonggye Plaza which heightened the balanced development in Seoul which has been developed in an unbalanced way by dividing into northern and southern area of the river is very meaningful in the viewpoint of the landscape architect who designs the urban space. The re-birth as a cultural space of downtown owing to the efforts of the said cultural catalysts is meaningful.

• Strategy21
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• s.44
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• pp.352-376
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• 2018

Through this research, the current state of naval coordination and guidance of shipping is reviewed whereupon which a suggestion is made for a novel role which satisfies the needs of the people and the country asked of the Navy. Taking into consideration the dynamic security environment, the developing relationship between the two nations on the Korean peninsula, and the influence that the Republic of Korea has on maritime security, it is made more urgent that the Navy takes a proactive course of action in terms of naval coordination and guidance of shipping. The current form of Korean naval coordination and guidance of shipping is adapted from the logical and flexible concepts of NCAPS and NCAGS and is one of many tasks that the Republic of Korea Navy must perform. However, when the Republic of Korea Navy develops blue-water capabilities with the ambitions of protecting its people and their way of life, naval coordination and guidance of shipping could potentially become one of the primary functions of the Republic of Korea Navy that the it must champion. Already, there are indications that foreign navies are, through many developments and commitment towards naval coordination and guidance of shipping, protecting its people and states' interests wherever is necessary. In the case of Chile, its Navy has taken the helm of naval coordination and guidance of shipping and has integrated various maritime organizations including the coast guard and the National Customs Service for the sake of maintaining regional maritime security, showing immediate force if necessary. Presently, as the Republic of Korea Navy looks to be a global naval power, it is important that a reprioritization of the Navy's mission is undertaken, all the while sustaining military readiness posture on the Northern Limit Line. It cannot be any more emphasized how crucial thorough military readiness posture is as a natural stance against the enemy. That being said, contributing towards international maritime security is consistent with the nation's standing. It is a fact that maritime security has been conceptualized and developed merely as a study within the Ministry of Maritime Affairs and Fisheries, the Republic of Korea Navy, and other governmental organizations, forces, and academia. Naval cooperation and guidance of shipping suggested by this research as a practical operational field is a concrete solution to what once was an abstract concept. To stand firm on its status as a maritime nation, the Republic of Korea must establish a Maritime Security Organization within its Navy and develop the appropriate doctrines. Attaining experts, developing doctrines, and cultivating the capability to deploy maritime forces will allow for the Republic of Korea to execute a primary role in keeping international maritime security and naval coordination and guidance of shipping. To fully achieve its latent potential necessitates the Republic of Korea Navy to expedite the introduction of naval coordination and guidance of shipping concepts and to establish the appropriate doctrines, operation plans, and organizations.