• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.1
• /
• pp.411-417
• /
• 2013

The moment responses of electric pole foundations for a railroad were investigated using real-scale load tests. Large overturning moments were applied to two square rigid piles with a 1.1 m width and a 2.2 m embedded depth. Two different installation methods-with and without a form-were applied to evaluate the influence of the form work on the moment capacities of the foundations. The reduction of ground strength caused by the excavation without a form is more pronounce than the decrease of frictional strength due to the smooth concrete surface with a form. From the test results, it is found that the current design method which applies a proportional coefficient to consider the effect of a form work is not appropriate. When the normal and frictional stressed is considered separately, the effect of a form work can be estimated reasonably by reducing the friction angle between soil and foundation by 20%.

• Journal of Fashion Business
• /
• v.14 no.6
• /
• pp.11-22
• /
• 2010

The main purpose of this research was to examine the linguistic characteristics of domestic men's formal wear brand name. Four linguistic characteristics of language type, combined structure type of language, word class, length of brand name were investigated in this research and also examined the difference between brand type. For sample selection, the 209 men's fashion brands were selected from '2009 Korea Fashion Yearbook' and then, 25 brands which could not collect proper informations about the brand name or naming were excluded. Among total 184 men's brand names, 66 men's formal wear brands were selected and studied. For data analysis, quantitative evaluation of the frequency and qualitative evaluation have been used. The result as follows.; (1) Seven language types were found in domestic men's formal wear brand names. English has been used the most, then followed by Italian and French. (2) For combined structure type of brand name language, the single word used the most, followed by separately combined word type, artificially combined word, and unified word type. (3) The most frequently used the type of word class was noun, and followed by phrase, adjective, and verb. In the noun type, 6 different types which expressed a person, concrete & abstract entity, place, acronym, and neologic were found. For phrase, only noun type was appeared, however, 6 out of 20 phrases were abbreviated type. All eight adjective brand names implied an attributive character of the brand such as 'Dainty' or 'Solus(Solo)'. (4) The long name used most and then followed by normal and short length of brand name. Looking by the number of syllable, 4 syllables appeared the most and then followed by 3, 5, 6, 2 & 7 showed the same rate, and 8 syllables. (5) The result which compared the difference according to each brand type showed a difference in its language type, language combined style, word class, but length of brand name.

• Journal of the Korea Institute of Building Construction
• /
• v.19 no.1
• /
• pp.19-29
• /
• 2019

In this study, a revised oil leakage evaluation method for assessing oil leakage stability of asphalt mastics used in upper slabs of below-grade residential parking lots was developed and presented. In order to verify the reliability and reproducibility of leakage results, the parameters the revised evaluation was carried out for three products with actual leakage history, and it was confirmed the leaks could be reproduced whereas the existing methods could not. To quantitatively verify the reproducibility, the filler content of the leaked samples was derived and the maximum filler content was 64% lower than that of the normal sample. The same results was found with the samples from the actual leakage site, thus verifying the reliability of the revised evaluation method.

• Structural Engineering and Mechanics
• /
• v.69 no.1
• /
• pp.11-20
• /
• 2019

The biaxial failure mechanism of transversally bedding concrete layers was numerically simulated using a sophisticated two-dimensional discrete element method (DEM) implemented in the particle flow code (PFC2D). This numerical modelling code was first calibrated by uniaxial compression and Brazilian testing results to ensure the conformity of the simulated numerical model's response. Secondly, 21 rectangular models with dimension of $54mm{\times}108mm$ were built. Each model contains two transversely bedding layers. The first bedding layer has low mechanical properties, less than mechanical properties of intact material, and second bedding layer has high mechanical properties, more than mechanical properties of intact material. The angle of first bedding layer, with weak mechanical properties, related to loading direction was $0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$ and $90^{\circ}$ while the angle of second layer, with high mechanical properties, related to loading direction was $90^{\circ}$, $105^{\circ}$, $120^{\circ}$, $135^{\circ}$, $150^{\circ}$, $160^{\circ}$ and $180^{\circ}$. Is to be note that the angle between bedding layer was $90^{\circ}$ in all bedding configurations. Also, three different pairs of the thickness were chosen in models, i.e., 5 mm/10 mm, 10 mm/10 mm and 20 mm/10 mm. The result shows that in all configurations, shear cracks develop between the weaker bedding layers. Shear cracks angel related to normal load change from $0^{\circ}$ to $90^{\circ}$ with increment of $15^{\circ}$. Numbers of shear cracks are constant by increasing the bedding thickness. It's to be noted that in some configuration, tensile cracks develop through the intact area of material model. There is not any failure in direction of bedding plane interface with higher strength.

• Computers and Concrete
• /
• v.27 no.3
• /
• pp.199-210
• /
• 2021

The aim of this paper was to examine the continuous and discontinuous contact problems between the functionally graded (FG) layer pressed with a uniformly distributed load and homogeneous half plane using an analytical method and FEM. The FG layer is made of non-homogeneous material with an isotropic stress-strain law with exponentially varying properties. It is assumed that the contact at the FG layer-half plane interface is frictionless, and only the normal tractions can be transmitted along the contacted regions. The body force of the FG layer is considered in the study. The FG layer was positioned on the homogeneous half plane without any bonds. Thus, if the external load was smaller than a certain critical value, the contact between the FG layer and half plane would be continuous. However, when the external load exceeded the critical value, there was a separation between the FG layer and half plane on the finite region, as discontinuous contact. Therefore, there have been some steps taken in this study. Firstly, an analytical solution for continuous and discontinuous contact cases of the problem has been realized using the theory of elasticity and Fourier integral transform techniques. Then, the problem modeled and two-dimensional analysis was carried out by using ANSYS package program based on FEM. Numerical results for initial separation distance and contact stress distributions between the FG layer and homogeneous half plane for continuous contact case; the start and end points of separation and contact stress distributions between the FG layer and homogeneous half plane for discontinuous contact case were provided for various dimensionless quantities including material inhomogeneity, distributed load width, the shear module ratio and load factor for both methods. The results obtained using FEM were compared with the results found using analytical formulation. It was found that the results obtained from analytical formulation were in perfect agreement with the FEM study.

• Geomechanics and Engineering
• /
• v.29 no.3
• /
• pp.281-290
• /
• 2022

The direct shear test is commonly used to evaluate the shear behavior of frozen soil-structure interfaces under normal stress. However, failure criteria, such as the Mohr-Coulomb failure criterion, are needed to obtain the unconfined shear strength. Hence, the punch shear test, which is usually used to estimate the shear strength of rocks without confinement, was examined in this study to directly determine the adfreezing strength. It is measured as the shear strength of the frozen soil-structure interface under unconfined conditions. Different soils of silica sand, field sand, and field clay were prepared inside the steel and concrete ring structures. Soil and ring structures were frozen at the target temperature for more than 24 h. A punch shear test was then conducted. The test results show that the adfreezing strength increased with a decrease in the target temperature and increase in the initial water content, owing to the increase in ice content. The adfreezing strength of field clay was the smallest when compared with the other soil specimens because of the large amount of unfrozen water content. The field sand with the larger normalized roughness showed greater adfreezing strength than the silica sand with a lower normalized roughness. From the experiment and analysis, the applicability of the punch shear test was examined to measure the adfreezing strength of the frozen soil-structure interface. To find a proper sample dimension, supplementary experiments or numerical analysis will be needed in further research.

• Composites Research
• /
• v.19 no.2
• /
• pp.13-19
• /
• 2006

In this paper, parametric study was carried out to design sandwich structures for EDM machines controlling stacking sequence, stacking thickness of composites and rib configuration. Sandwich structures which are dealt with in this paper are composed of fibre reinforced composite for skin material and foam or resin concrete for core materials. The sandwich column has cruciform rib to enhance bending stiffness of the structure and the bed has several vertical ribs to resist the normal forces and vibration. The design parameters such as rib thickness and stacking sequence were controlled to enhance the system robustness. Finite element analysis was also carried out to verify the variation of static and dynamic stiffness of the structures according to the variation of the parameters. Vibration tests were performed to verify the natural frequencies and damping ratios of the manufactured composite structures. The appropriate shape and configuration conditions for micro-EDM machine structures are proposed.

• Advances in concrete construction
• /
• v.15 no.4
• /
• pp.251-267
• /
• 2023

In this paper, an experimental investigation is carried out to assess the inherent self-compacting properties of geopolymer mortar and its impact on flexural strength of thin-walled ferro-geopolymer box beam. The inherent self-compacting properties of the optimal mix of normal geopolymer mortar was studied and compared with self-compacting cement mortar. To assess the flexural strength of box beams, a total of 3 box beams of size 1500 mm × 200 mm × 150 mm consisting of one ferro-cement box beam having a wall thickness of 40 mm utilizing self-compacting cement mortar and two ferro-geopolymer box beams with geopolymer mortar by varying the wall thickness between 40 mm and 50 mm were moulded. The ferro-cement box beam was cured in water and ferro-geopolymer box beams were cured in heat chamber at 75℃ - 80℃ for 24 hours. After curing, the specimens are subjected to flexural testing by applying load at one-third points. The result shows that the ultimate load carrying capacity of ferro-geopolymer and ferro-cement box beams are almost equal. In addition, the stiffness of the ferro-geoploymer box beam is reduced by 18.50% when compared to ferro-cement box beam. Simultaneously, the ductility index and energy absorption capacity are increased by 88.24% and 30.15%, respectively. It is also observed that the load carrying capacity and stiffness of ferro-geopolymer box beams decreases when the wall thickness is increased. At the same time, the ductility and energy absorption capacity increased by 17.50% and 8.25%, respectively. Moreover, all of the examined beams displayed a shear failure pattern.

• Journal of Korea Trade
• /
• v.26 no.3
• /
• pp.79-101
• /
• 2022

Purpose - The purpose of this study is to analyze and compare the international competitiveness of digital service trade between Korea and China and to help enhance the competitive advantage of digital service trade between the two countries. Design/methodology - This paper designs and establishes a comprehensive evaluation system for the international competitiveness of the Korea-China digital service trade. By using the analytical methods of combining theory and demonstration through qualitative and quantitative analysis, this paper makes a concrete and complete theoretical deconstruction and empirical measurement of its international competitiveness from the two levels of overall competitiveness and departmental competitiveness. At the same time, the study also analyzes the competitive advantages and comparative disadvantages of the two countries. Findings - It is found that South Korea has a strong competitive advantage in the sector competitiveness of digital service trade, and the export structure is reasonable and balanced, but the deficit pattern affects the overall competitiveness. China has a strong competitive advantage in the overall competitiveness of the digital service trade. However, the structural imbalance in the export sector weakens the competitiveness of the sector. Both Korea and China have the space advantage and competitive potential to enhance international competitiveness in terms of development trends. Originality/value - This paper takes the lead in solving the pain point of the relative lack of similar research topics. It demonstrates the evolution process, development trends, and structural characteristics of the digital service trade. A new combination of competitive power research methods is innovated, and a comprehensive evaluation system is established. The above innovation points show the academic theoretical value and practical application value of this study.

• Journal of Digital Convergence
• /
• v.20 no.3
• /
• pp.265-273
• /
• 2022

The purpose of this study is to take a look the situation of social enterprises under CIVID-19 Pandemic and to suggest future directions. The COVID-19 pandemic which started at the end of 2019, has influenced the various areas of our society, such as health, economic, social and networking. The virus is spread through human respiratory, and it is working as a disability factor in human focused social economy. Under the COVID-19 pandemic situation, Social entrepreneurs are being constrained in financial aspects. In the process of continuing pandemic, the size of the social economy has been expanded and cleaning & health businesses are showing economic performance. This is to tell the fact that social economy is solving COVID-19 issues based on a reciprocity and solidarity. To create a sustainable ecosystem for the social economy, we should select and promote universal and concrete future directions at the economic and social safety net building level rather than to respond to COVID-19.