• Journal of the Korean Society of Environmental Restoration Technology
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• v.15 no.6
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• pp.29-41
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• 2012

This study was conducted in Ningxia Hui autonomous region, located at southern part of Mu Us sand land in China. To investigate relationships between windbreak effect and installation cost of sand barriers, plastic net is utilized by using four kind of heights (0.2, 0.3, 0.4 and 0.5m) and four kind of porosities (20, 30, 50 and 70%). These heights and porosities are measured for estimating distances for effective windbreak. It is shown that porosity and the distance have a positive relationship at same heights and porosity on ground indicates a constant figure when height reaches a certain level, regardless of the porosity. This implies that there is a difference of level of windbreak with different porosities; however, distance of windbreak effect is same at the same height of sand barrier. As a result of comparison between porosity of sand barrier on the ground and installation cost in each sand barrier with various heights and porosities (16 combinations), 0.4m and 0.5m height sand barriers describe highest economical efficiency. Within two variables, we concluded that height has a higher impact on windbreak effect than porosity.

• The Journal of Asian Finance, Economics and Business
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• v.6 no.4
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• pp.53-63
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• 2019

The paper examines the influence of profitability on distance to default (DD) in Vietnam securities market. The investigated sample consists of 211 companies listed on HOSE during 18 years from 2010 to 2017. We apply KMV model to calculate distance to default and use both macroeconomics factors and firm specific factors as independent variables. Using General Least Squared (GLS) method, we find evidence to confirm the positive relationship between profitability and distance to default. This result showed that, although profitability did not directly reflect the cash flow generated, a good profitable enterprise would be an important factor to help facilitate and generate cash flow and at the same time debt was guaranteed when it was due. Besides, the test results revealed that the financial structure and sales on assets have the inverse effect on the distance to default at the significance level of 5%. The results also revealed that a group of macro factors had an influence on the distance to default of businesses, including spread, GDP and trade balance (via exchange rates). Gross domestic income had certain impacts on the distance to default of businesses. This was also a basic indicator measuring the national economic cycle.

• The Journal of the Korea Contents Association
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• v.15 no.8
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• pp.424-433
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• 2015

This study tried to investigate the differences between auditory preferences for a discrimination study of minimal pairs with the different onset and the same nucleus of a syllable on the basis of articulator-distance in case of Korean infants and toddlers. As a result we found a main effect for articulator-distance and age but not an effect according to the types of phonation especially in terms of tense. Former results are line with the previous studies having reported the order of consonants acquisition based on the places of articulation suggesting that more sensitive responses for the contiguous and different phonemes may lead earlier acquisition for the same place of articulation of the speech sounds. Specifically, bilabial soudns are followed by alveolar and palatal sounds in order. The latter results also showed that tense consonants got a high rate of recognition beside lax consonants according to the age and sex.

• Korean Institute of Interior Design Journal
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• v.15 no.4 s.57
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• pp.123-128
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• 2006

The purpose of the research is to estimate the amount of a color image reaction variation by changing areas in order to design the method to reduce an error about the color sample when it is applied in the real situation. The summary of the results acquired in this research is as followed. (1) With fixed observing distance of 1m, we observed that the value and chroma of each color object became higher as sight angle was increased as $2^{\circ},\;10^{\circ},\;and\;30^{\circ}$, even though the variation ratio was different. (2) With fixed sight angle of 10, we observed that the value and chroma of each color object becane higher as observing distance was changed from 1m to 3.3m, even though the variation ratio was different. (3) With same area, we observed that the values and chromas of each color object in the conditions of $1m-30^{\circ}\;and\;3.3m-10^{\circ}$ were almost same. (4) When the area became larger, the subjects tended to feel that colors were bright and clear with the increase of tone. In all the colors, the variation of a color reaction in chroma is higher than those in value. In future, we can observe the limit in applying to colors in the architecture by identifying the tendency of the color change according to the area change qualitatively.

• Geomechanics and Engineering
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• v.15 no.3
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• pp.911-917
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• 2018

This paper concerns a numerical investigation on the effect of construction sequence on three-arch (3-Arch) tunnel behavior. A three-arch tunnel section adopted in a railway tunnel construction site was considered in this study. A calibrated 3D finite element model was used to conduct a parametric study on a variety of construction scenarios. The results of analyses were examined in terms of tunnel and ground surface settlements, shotcrete lining stresses, loads and stresses developed in center column in relation to the tunnel construction sequence. In particular, the effect of the side tunnel construction sequence on the structural performance of the center structure was fully examined. The results indicated that the load, thus stress, in the center structure can be smaller when excavating two side tunnels from opposite direction than excavating in the same direction. Also revealed was that no face lagging distance between the two side tunnels impose less ground load to the center structure. Fundamental governing mechanism of three-arch tunnel behavior is also discussed based on the results.

• Explosives and Blasting
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• v.32 no.1
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• pp.1-9
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• 2014

TNT was blasted on the surface of steel plates and concrete block to study the effect of separation distance between object and charge. The equation of US Army Corps of Engineers turned out to be rather conservative. Effect of separation distance is larger for steel plate than concrete block. Steel plate cannot be cut by standard or more charge in the case of 2 cm separation while the concrete block can be crushed with the same distance.

• Journal of Korea Multimedia Society
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• v.4 no.5
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• pp.430-438
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• 2001

In this paper, we present the design and implementation of a web-based distance learning system supporting the collaborative browsing. Our system consists of an education affair management system, a video conferencing server/client, a white-board server/client, a session manager and a web browser sharing system. Among other things, our collaborative web browser is unique and not found in any other system. The web browser shows synchronously the same web pages as the lecturer moves through them. Therefore, it allows the student to feel real-time surfing gust as the lecturer would. The session manager supports multi-user and multi-group, and integrates various synchronous collaborative component into one distance learning system by providing the same session data and information of users in a session group. Our collaborative browsing system can increase the efficiency of distance learning and provides the effect of learning in the same classroom by supporting various synchronous functionalities, such as collaborative browsing.

• Transactions of Materials Processing
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• v.13 no.2
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• pp.122-128
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• 2004

In order to make a doubly-curved sheet metal effectively, a sheet metal forming process has been developed by adopting the flexibility of the incremental forming process and the principle of bending deformation which causes slight deformation in thickness. The developed process is an unconstrained forming process with no holder. For this study, the experimental equipment is set up with the roll set which consists of two pairs of support rolls and one center roll. In the experiments using aluminum sheets, it is found that the curvature of the formed sheet metal is determined by controlling the distance between supporting rolls in pairs and the forming depth of the center roll and it also depends on the thickness of the sheet metal. In order to check the effect of process parameters on the generation of sheet metal curvatures in this process, the orthogonal array is adopted. From the experimental results, among the process parameters, the distance between supporting rolls in pairs along the direction of one principal radius of curvature as well as the forming depth and the thickness of the material is shown to influence the generation of curvature in the same direction significantly. That is, the other distance between supporting rolls in pairs which are not located in the same direction of one principal radius of curvature, does not have an significant effect on the generation of the curvature in that direction. It mainly affects the generation of curvature in its own direction with the forming depth and the thickness of the material.

• Journal of the Korean Wood Science and Technology
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• v.48 no.4
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• pp.562-568
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• 2020

This study investigates the relationship between ultrasonic velocity and density in the direct method, the effect of distance between transducers in the indirect method, and the difference between the direct and indirect methods with transducers placed at a distance of 200 mm in nondestructive ultrasonic testing of spruce lumber. The direct method using 54 kHz ultrasonic transducers was applied to two planes, namely, radial section (LR) and tangential section (LT) of samples. The indirect method measurements were taken using the same transducers. Two velocities were measured at the top and bottom of the LT plane and at the two sides of the LR plane; the two values for each plane were averaged. The relationship between density and ultrasound velocity in the direct method demonstrated a positive correlation between the two variables. The difference between the two planes, LT and LR, was not statistically significant. Moreover, the distance between the transducers in the indirect method affected ultrasound velocity, with the ultrasonic velocity increasing as the distance between the transducers became larger. A transducer distance of 200 mm yielded a close approximation of the direct method results with a ratio of 0.87. Finally, no statistical evidence of a difference between the two planes in the indirect method was found. If the direct method, which requires access to two surfaces, is impractical, the indirect method can be applied.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.4
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• pp.419-425
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• 2014

The current work investigated the variation of numerical solutions according to the grid number, the distance of the first grid point off the ship surface, turbulence modeling and discretization. The subject vessel is KVLCC. A commercial code, Gridgen V15 and FLUENT were used the generation of the ship hull surface and spatial system and flow computation. The first part of examination, the effect of solutions were accessed depending on the grid number, turbulence modeling and discretization. The second part was focus on the suitable selection of the distance of the first grid point off the ship surface: $Y_P+$. When grid number and discretization were fixed the same value, the friction resistance showed differences within 1 % but the pressure resistance showed big differences 9 % depending on the turbulence modeling. When $Y_P+$ were set 30 and 50 for the same discretization, friction resistance showed almost same results within 1 % according to the turbulence modeling. However, when $Y_P+$ were fixed 100, friction resistance showed more differences of 3 % compared to $Y_P+$ of 30 and 50. Whereas pressure resistance showed big differences of 10 % regardless of turbulence modeling. When turbulence modeling and discretization were set the same value, friction, pressure and total resistance showed almost same result within 0.3 % depending on the grid number. Lastly, When turbulence modeling and discretization were fixed the same value, the friction resistance showed differences within 5~8 % but the pressure resistance showed small differences depending on the $Y_P+$.