• Steel and Composite Structures
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• v.21 no.4
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• pp.805-827
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• 2016

A new type of precast CFST column to RC beam braced frame is proposed in this paper. A series of shake table tests were conducted to excite a one-third scale six-story model for investigating the global seismic performance of this type of structure against earthquake actions. Particular emphasis was given to its dynamic property, global seismic responses and failure path. Correspondingly, a numerical model built on the basis of fiber-beam-element model, multi-layer shell model and element-deactivation method was developed to simulate the seismic performance of the prototype structure. Numerical results were compared with the measured values from shake table tests to verify the validity and reliability of the numerical model. The results demonstrated that the proposed novel precast CFST column to RC beam braced frame performs excellently under strong earthquake excitations; the "strong CFST column-weak RC beam" and "strong connection-weak member" anti-seismic design principles can be easily achieved; the maximum deflections of precast CFSTC-RCB braced frame satisfied the deflection limitations proposed in national code; the numerical model can properly simulate the dynamic property and responses of the precast CFSTC-RCB braced frame that are highly concerned in engineering practice.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.7 no.3
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• pp.233-240
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• 1995

A large part of shoaling of navigation channel surrounded by fine sand is caused by suspended sediment in non-equilibrium state. We develop a numerical model for predicting shoaling of navigation channel where concentration of suspended sediment in such state is accurately simulated. In this study, effects of channel geometry on the shoaling of the channel are investigated numerically. A composite slope of navigation channel is also proposed to reduce non-equilibrium property of suspended sediment. It is found that the composite slope can effectively reduce non-equilibrium property of suspended sediment and the amount of sediment deposited in the main channel.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.19 no.4
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• pp.337-342
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• 2001

A natural disaster occupies a considerable part among various damages, and the damage of human lifes and property by heavy rain extends to hundreds, and billions in every you. In old times, flood was mainly occurred in big river or sudden slope, but these days, the damage of concentrated heavy rain is being extended to a city. Recently, very big floods occurred continuously, so real time submersion expectation system which can expect the inundation boundary according to the scale is needed so as to protect lifes and property. In this study, in and around Jungrang river, where the damage of flood is big, is chosen as a sample, and the submersion of that area is expected by analyzing the flux and overflowing using DEM, and connecting with Web GIS in real time.

• Culinary science and hospitality research
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• v.14 no.3
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• pp.178-195
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• 2008

This examination was conducted as follows; 189 copies were coated in total, and demonstratively analyzed by SPSS WIN 15.0 program. The methods used in data for this analysis are as follows; Sensitivity, Reliability, Frequency, Internal consistency, One way ANOVA(Scheffe's examination) Analysis, T-test, etc. The findings of this study are as follows; firstly, it was revealed that respondents who were regular customers of Italian restaurants regarded convenient transportation, property of space, property of pastoral, visibility, and accessibility as importance. This means that Italian restaurant marketers should consider some of factors of location for business with a good view, good parking lot, location at main street, smooth flow of traffic, luxury, atmosphere of freedom, clean area around restaurants, elegant interior of the building, comfortable, luxurious, and deluxe atmosphere, and so on. Secondly, it was revealed that respondents who were regular customers of buffet restaurant either considered the same factors as the Italian restaurants above or regarded those factors less important. This suggests that restaurants should be located on main streets, on trunk roads, and in large-scale residential districts of apartment complex. Thirdly, it was revealed that respondents who were regular customers of traditional restaurants did not consider the locational factors above. This shows that traditional restaurants should be located in nearby customers' houses or their working places, and that marketers should consider focusing on their restaurants' homelike atmosphere, cleanliness, food flavors, and so on.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2007.11a
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• pp.876-879
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• 2007

Large scale composition facility gives in commerce and space structure effect. therefore, this study will estimating locational value of the commercial facilities by separating space analyze to the topological property, predict a pattern and distribution of passenger's routes through the space syntax on the basis of analysis about the topological property which quantitatively using a estimating tool. Moreover, this study should suggest some of present issues at the aspects of inside city plan and design fitting the internalization of street for propelling efficient the locational strategy.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.2
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• pp.36.3-37
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• 2015

4C39.25 (0923+392) is a distant radio loud AGN placed at redshift 0.695. The motivation of our work is peculiar properties 4C39.25. Firstly, it has a conspicuous distinction of jet direction between kilo-parsec scale observation made by VLA (Kollgaard et al. 1990) and the parsec scale observation by VLBA (Kellermann et al. 1998). This might indicate episodic-jet activity which recently turned on. This object currently shows two stationary compact parsec-scale components which are bright jet component on east and less luminous core on west. Also, it is known that there have been superluminal jet components which are flowing from the core toward east, and then merging with the bright jet component (Marscher et al. 1991, Alberdi et al. 2000, Lister et al. 2013). Although 4C39.25 seems to be a blazar-like source having broad emission lines (SDSS) and superluminal motion, its property that jet component is brighter than the core is different from ordinary blazars. Furthermore, it has young radio galaxy-like properties such as non-variation in total flux (Alberdi et al. 1997, 2000, MOJAVE database) and high frequency peak at spectral energy distribution (Orienti et al 2007). Such complex properties led us to make recent observations to reveal precise properties and new changes of the source. We used Korean VLBI Network (KVN) and VLBI Exploration of Radio Astronomy (VERA) Array (KaVA) which provide high-frequency (23GHz and 43GHz) and high spatial resolution (1.2mas and 0.6mas). Therefore, this system is suitable for morphological and physical research on parsec scale structure. We present results for several epochs observed during 2013 to 2014, mainly focusing on morphological changes of 4C39.25 using KaVA images.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.8
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• pp.459-466
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• 2014

Fading effect of old pictures and printings is shown up differently according to the ink property, temperature, humidity, illuminants, and so on. Faded image enhancement techniques based on illuminant estimation are proposed such as the gray world algorithm and white patch retinex methods. However, conventional simple operators are not suitable for enhancing faded images because partial fading effect is appeared differently. Thus, this paper presents a color enhancement algorithm based on integrating correction coefficients for faded images. First, the proposed method adopts local process by using multi-scale average mask. The coefficients for each multi-scale average mask are obtained to apply the gray world algorithm. Then, integrating the coefficients with weights is performed to calculate correction ratio for red and blue channels in the gray world assumption. Finally, the enhanced image is obtained by applying the integrated coefficients to the gray world algorithm. In the experimental results, the proposed method reproduces better colors for both wholly and partially faded images compared with the previous methods.

• Journal of computational fluids engineering
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• v.22 no.1
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• pp.43-50
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• 2017

Thermal flowfield of a micro turbojet engine was computationally investigated for exhaust nozzles with different aspect ratio and curvature. Special attention was paid to maximum and average temperature of the nozzle surface and the exhaust nozzle plume. The IR signatures of the micro turbojet engine nozzle were then calculated through the narrow-band model based on thermal flowfield data obtained through CFD analysis. Finally, in order to check the similarity of thermal flowfields and IR signature of the sub-scale micro turbojet engine model and the full-scale UCAV propulsion system, several non-dimensional parameters associated with temperature and optical property of plume were introduced. It was shown that, in spite of some differences in actual values of non-dimensional parameters, the scaling characteristics on spectral feature of IR signature and effects of aspect ratio and curvature of nozzle configuration remain similar in sub-scale and full-scale cases.

• Journal of Powder Materials
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• v.21 no.3
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• pp.207-214
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• 2014

In this study, nano-scale copper powders were reduction treated in a hydrogen atmosphere at the relatively high temperature of $350^{\circ}C$ in order to eliminate surface oxide layers, which are the main obstacles for fabricating a nano/ultrafine grained bulk parts from the nano-scale powders. The changes in composition and microstructure before and after the hydrogen reduction treatment were evaluated by analyzing X-ray diffraction (XRD) line profile patterns using the convolutional multiple whole profile (CMWP) procedure. In order to confirm the result from the XRD line profile analysis, transmitted electron microscope observations were performed on the specimen of the hydrogen reduction treated powders fabricated using a focused ion beam process. A quasi-statically compacted specimen from the nano-scale powders was produced and Vickers micro-hardness was measured to verify the potential of the powders as the basis for a bulk nano/ultrafine grained material. Although the bonding between particles and the growth in size of the particles occurred, crystallites retained their nano-scale size evaluated using the XRD results. The hardness results demonstrate the usefulness of the powders for a nano/ultrafine grained material, once a good consolidation of powders is achieved.

• Journal of the Korean Chemical Society
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• v.59 no.2
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• pp.148-155
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• 2015

ZnO nanoplates were prepared by seed-mediated soft-solution process. Photocatalytic property of ZnO nanoplates was superior to that of conventional ZnO nanoparticles owing to the enhanced (0001) plane with large defect sites. In addition, we found that silica coating method could provide to reduce cytotoxicity of ZnO nanoplates. Finally, we have successfully synthesized for the first time large-scale synthesis of plate-type ZnO as few hundreds gram scale for industrial applications through controlling various reagents of growth solution.