• Design & Manufacturing
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• v.2 no.1
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• pp.45-50
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• 2008

Micro channel is to fabricate desired pattern on the polymer substrate by pressing the patterned mold against the substrate which is heated above the glass transition temperature, and it is a high throughput fabrication method for bio chip, optical microstructure, etc. due to the simultaneous large area patterning. However, the bad pattern fidelity in large area patterning is one of the obstacles to applying the hot embossing technology for mass production. In the present study, stamper of cross channel with width $100{\mu}m$ and height $50{\mu}m$ was manufactured using UV-LiGA process. Micro channel was manufactured using stamper manufactured in this study. Also replicability appliance was evaluated for micro channel and factors affected replicability were investigated using Taguchi method.

• Transactions of the Korean hydrogen and new energy society
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• v.20 no.6
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• pp.479-484
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• 2009

The effect of anode gas channel height on gas diffusion and cell performance in a 100 $cm^2$ class molten carbonate single cell is investigated. Single cell separators with three different channel height are used. The effect of the gas channel height on the distribution of the reactive gas concentration is evaluated by the two-dimensional concentration diffusion equation. The overpotential caused by concentration drop with different channel height is estimated by the voltage decay related to diffusion of reactants, well known as concentration polarization, using limiting current density. The estimation could have the possibility to identify the reactant mass transfer polarization in the complicate factors of the overall electrodes.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.609-610
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• 2017

Cognitive radio communication techniques have been attracting attention to efficiently use the scarce spectrum as the wireless communication service increases. In cognitive radio communication, efforts to minimize interference to the primary user are important technical factors. In a multi-hop wireless ad hoc network, multi-hop transmission requires path and channel selection considering channel interference as well as collision with primary users. In the multi-channel environment, cognitive radio network has different capacities depending on the inter-channel interference and collision with the main users. In this paper, we propose a multi-hop transmission scheme that minimizes inter-channel interference and reduce collision with primary users.

• Journal of Korea Water Resources Association
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• v.35 no.3
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• pp.251-259
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• 2002

Flow characteristics occurring a side-weir overflow in rectangular channel is investigated in this study. A numerical model based on the two -dimensional shallow-water equations is employed to review the factors influencing on the side- weir overflow discharge and the change of flow depths and velocities. It is found that the discharge coefficient which has the most significant influence on the overflow is affected by geometric characteristics of a side-weir, Froude number of the main channel flow and the flow depth of the main channel at the starting point of a side-weir. And the discharge coefficient applicable to a practical design of a side-weir is proposed by deriving a relationship between Froude number of the main channel flow at the starting point of a side-weir and Froude number of the main channel flow.

• Journal of the Korean Society of Visualization
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• v.19 no.3
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• pp.69-76
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• 2021

Printed circuit heat exchanger (PCHE) is a compact heat exchanger with good heat transfer performance, high structure integrity, and reliability over a wide range of temperatures and pressures. Instead of the traditional zigzag and straight shape channel, the sinusoidal shape channel was adopted in this study to investigate the relation of thermal-hydraulic performance and waviness factors (period and amplitude). The local flow characteristics and the heat flux distribution were compared to verify the effects of period and amplitude on heat transfer performance. As the period of channel becomes shorter, the rapid change of the flow direction can produce high flow separation around the corner leading to the disturbance of the boundary layer opposite wall. The nonuniform distribution of flow velocity appeared around the corner positions can promote fluid mixing and lead to higher thermal performance. An evaluation index was used to compare the comprehensive performance of PCHE considering the Nusselt number and Fanning factor. Based on the simulation results, the optimal design parameters of PCHE channel shape were found that the channel with an equivalent bending angle of 15° offers the highest heat flux capacity.

• Journal of Distribution Science
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• v.21 no.1
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• pp.119-128
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• 2023

Purpose: Due to COVID-19, the rapidly changing untact culture from offline to online has spread rapidly, increasing the utilization of omni-channel. However, among the studies on consumers in the online market, there are not many studies that analyze Shopping Values and attitudes toward omnichannel Acceptance. Research design, data, and methodology: This study investigated through empirical analysis how Shopping Values and innovation propensity of consumers using omni channels affect omni channel Acceptance attitudes. The analysis results based on a total of 268 questionnaires using SPSS v.23 and AMOS v.23 statistical programs are as follows. Results: First, it was found that the perceived Value of omnichannel use had a positive effect on the innovation tendency, and the pleasure Value had a greater effect than the actual Value. Second, it was found that the practical and hedonic Value of the omnichannel had a positive effect on the attitude of service Acceptance. Third, it was found that Omni Channel's consumer innovation tendency had a positive effect on service Acceptance attitude. Conclusion: This study proved that Shopping Value perception and individual innovation propensity for omnichannel services have a positive effect on Acceptance attitude, and it is of academic significance in that it expanded understanding of what factors are needed to increase Acceptance attitude of Omni Channel services.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.131-143
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• 2003

The purpose of this study was to develop a new method for evaluation of stream naturalness in order to promote stream managers' understanding on importance of improving stream naturalness, and in order to appraise and prescribe for streams effectively in the process of ecological restoration of stream corridors. In order to analyze the evaluation method of stream naturalness and its applicability to streams, stream naturalness index(SNI) which has seven factors such as channel development, longitudinal profile, lateral section, stream bed structure, low flow channel structure, stream surroundings and water quality was suggested in this paper. For case studies, Bokha stream was selected for the evaluation of stream naturalness. At the Bokha stream, the scores of SNI factors were in range of $2.2{\sim}3.8$, and the average of SNI was 3.1, and the most frequent grade of SNI factors was grade 3. Among the 7 factors, the best was lateral section, and the worst was channel development. In this study, SNI grade can represent the characteristics of stream naturalness well and select the streams which will be restored, and can also decide the segment and the method of restoration for deteriorated streams.

• Water for future
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• v.14 no.1
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• pp.39-49
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• 1981

The purpose of this study is to examine the meander charactericstics for the rivers in Korea..In this study, the new characteristics factors of meander are proposed, and the relationships among the factors proposed in this study and the existing factors are derived. An attempt is made to find considerable relation among meander characteristics, but width and meander belt did not show any defined trend and considerable scatter of points was observed. Relationships among the meander length, belt and flowrate, etc., which are factors of meander characteristics, are analyzed the 67 rivers above 30km in length. Channel shape factor which is the ratio of the length from the starting point to the end to the channel lenght, tortuosity which is the ratio of the curved channel length against the channel length are suggested for a new characteristics factor of meander. They are well correlated with channel length, Horton's shape facotr and meander gradient, consequently have to be important measures of river meander. The result of the detailed comparison and the analysis of degree of sinuosity, velocity and water surface slop are brought light on the fact show that the curved reach is morestable than the straight one. The ratio of the meander length to the meander belt and its accumulative frequency showed excellent correlationship when plotted on the semi-log paper. The results of regression analysis of meander belt and meander length show linear for the South Han river branches and power curve for the Geum river and the Nakdong river branches.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.10 no.1
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• pp.209-246
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• 1997

In the literatual study on the Ecthyma, the results were as follows. 1. The pathogenic factors of Ecthyma is divided three parts. One is exogenous pathogenic factors which including the wind evil, wind heat and toxic material produced by wetness evil. Another is endogenous pathogenic factors which including the declination of kidney-yang, impairment of the liver and kidney, the lower classes of yin-fire, accumulation of wetness-heat in the spleen asthenia, impairment of the liver and kidney, wetness-heat of three yang, asthenic heat-syndrome of three yin. The other is pathogenic factors neither endogenous nor exogenous which including the food and living, uncontrol sexual excess, anxiety and angry, injury of skin, injury of insects and animals. 2. Five viscera which was concerned with Ecthyma are liver, spleen and kidney. 3. Frequent region of Ecthyma are S-36(足三里) and C-7(陰交). External Ecthyma was rose to wetness-heat of three yang channel that cured easily. Internal Ecthyma was rose to asthenic heat-syndrome of three yin channel that cured hardly. 4. In the frequency of prescription, the most numerous prescription is Bojungikgitang(補中益氣湯) and the next are Kyukgigo(隔紙膏) and Yukmijihwanghwan(六味地滉丸). 5. In the frequency of medicine, the most medicine is Calomelas(輕粉) which included Hydrargyrum(水銀) and the next are Olibanum(乳香) and Resina Commiphorae Myrrhae(沒藥) which regulating vital energy and pain control medicine used that in order to destroy insects and remove polson. 6. In classification of the medical action, medicine of clearing away summer-heat and heat evil and activating blood circulation to dissipate blood stasis used to be very busy which in order to remove the disorder of vital energy for virulent heat-evil. 7. In classification of four characters, the most part is warm medicine, the next are cold and cool medicine and there is a few that is hot medicine. 8. In classification of five tastes, the most numerous tastes are bitter and acrid, the next are sweet, salty and sour tastes. 9. In classification of virulence of medicine, the most part is non-toxic, the next are weakly and deadly poison. 10. In classification of channel distribution, the most is the medicine that belongs to liver channel, the next are the lung, spleen, stomach and kidney channel.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.169-174
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• 2004

To design ship channel is one of important factors for planning and developing a port. In most case, the core factors for designing ship channel are the layout and width of dvnnel provided the net underkeel clearance is assessed as safety. In this study, Variable Bumper Area(VBA) model is applied to design and assess ship channel. This model reflects ship's principle dimension, ship domain theory, ship speed, conning officer's ship handling skill and experience and all external forces which cause leeway, set and drift and the change of ship maneuvering characteristics. Full Mission Ship Handling Simulator is used to analyze ship dynamic data according to conning officer's ship control, external forces, etc. This model uses Domain-index for assessing the efficiency and safety of the channel. The proposed model is applied to Ulsan new port plan which has a channel width of 1.5 times the length if the largest vessel, a radius if 5 times the length of the largest vessel in a curve of 57 degree centerline angle and SBM facility adjacent to the lateral edge if channel. The result of this study shows tint the width and radius of channel curve are suitable for the target ship but the difficulty of ship handling is caused by the large course change and SBM located in the vicinity if channel.