• Advances in concrete construction
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• v.10 no.2
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• pp.151-159
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• 2020

An experimental study on the stress-strain relation of PVC-CFRP confined reinforced concrete columns subjected to eccentric compression was carried out. Two parameters, such as the CFRP strips spacing and eccentricity of axial load, were considered. The experimental results showed that all specimens failed by compressive yield of longitudinal steel bar and rupture of CFRP strips. The bearing capacity of specimen decreases as the eccentricity or the CFRP strips spacing increases. The stress-strain relation of specimens undergoes two stages: parabolic and linear stages. In the parabolic stage, the slope of stress-strain curve decreases gradually as the eccentricity of axial loading increases while the CFRP strips spacing has little effect on the slope of stress-strain curve. For the linear stage, the slope of stress-strain curve decreases as the eccentricity of axial load or the CFRP strips spacing increases. A model for predicting the stress-strain relation of columns under eccentric compression is proposed and it agrees well with various test data.

• Journal of the Korea Society of Computer and Information
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• v.25 no.2
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• pp.157-162
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• 2020

In this paper, we propose an analyze the effects of CPR education for kindergarten students, to determine their role as first responders, and to use them as basic data for the development and activation of CPR education programs for future kindergarten students. Five CPR training sessions were repeated for 10 weeks for children aged 6 and 7 years in kindergarten in J city, and objective data was collected using feedback equipment. The data were analyzed by t-test and paired t-test using SPSS 23.0 for win statistics program. The results showed that chest compression depth, chest compression velocity, and chest compression hand position increased significantly after repeated training. In conclusion, the cardiopulmonary resuscitation training for kindergarten students was effective, and the kindergarten students could play the role of first responders.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.604-611
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• 2016

This paper describes the characteristics of n-Butane fuel for the homogeneous charge compression ignition (HCCI) engine for a new concept. HCCI engines are being considered as a future alternative for diesel and gasoline engines. From the experimental observations, the effect of n-Butane fuel in HCCI engine on CO, HC and NOx are analysed. The objective of this paper is to clear the effects of equivalence ratio and inlet temperature with n-Butane on the HCCI. For this purpose, a 4-cylinder, compression ignition engine was converted into a HCCI engine This work has been run with n-butane fuel at a constant speed.

• The KIPS Transactions:PartB
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• v.11B no.3
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• pp.303-308
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• 2004

The Gabor cosine and sine transform can be applied to image and video compression algorithm by representing image frequency components locally The computational complexity of forward and inverse matrix transforms used in the compression and decompression requires O($N^3$)operations. In this paper, the length of basis functions is truncated to produce a sparse basis matrix, and the computational burden of transforms reduces to deal with image compression and reconstruction in a real-time processing. As the length of basis functions is decreased, the truncation effects to the energy of basis functions are examined and the change in various Qualify measures is evaluated. Experiment results show that 11 times fewer multiplication/addition operations are achieved with less than 1% performance change.

• Elastomers and Composites
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• v.40 no.4
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• pp.258-265
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• 2005

To study the compressive stress, recovery force and permanent strain of foams for footwear midsole, polyurethane(PU), phylon(PH) and injection phylon(IP) foams were repetitively compressed with constant compressive stress. Maximum compressive stress of PU did not decrease with repetitive compression on the constant compressive stress, but that of IP largely decreased. Engineering strain of foams were formed by repetitively compressing the three types of foam. The engineering strain of PU was smaller than that of IP and PH. Compressive stress and recovery force of IP and PH at certain strain were decreased with repetitive compression, but that of PU was not noticeably changed.

• Structural Engineering and Mechanics
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• v.70 no.3
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• pp.269-277
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• 2019

Using the non-local elasticity theory, Timoshenko beam model is developed to study the non- local buckling of Triple-walled carbon nanotubes (TWCNTs) embedded in an elastic medium under axial compression. The chirality and small scale effects are considered. The effects of the surrounding elastic medium based on a Winkler model and van der Waals' (vdW) forces between the inner and middle, also between the middle and outer nanotubes are taken into account. Considering the small-scale effects, the governing equilibrium equations are derived and the critical buckling loads under axial compression are obtained. The results show that the critical buckling load can be overestimated by the local beam model if the small-scale effect is overlooked for long nanotubes. In addition, significant dependence of the critical buckling loads on the chirality of zigzag carbon nanotube is confirmed. Furthermore, in order to estimate the impact of elastic medium on the non-local critical buckling load of TWCNTs under axial compression, the use of these findings are important in mechanical design considerations, improve and reinforcement of devices that use carbon nanotubes.

• Journal of Korean Physical Therapy Science
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• v.28 no.1
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• pp.1-10
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• 2021

Background: This study is goal to explore the effects of swiss ball exercise on muscular strength, flexibility, and balance in healthy adults with and without pelvic compression belts. Design: Randomized Controlled Trial. Methods: This study randomly divided the experimental and control groups in 24 healthy adults wearing pelvic compression belts, and they conducted Swiss ball exercise programs, 5 times for 40 minutes a week during 3 weeks in conclusion 15 times. Results: The results showed that the experimental groups have increased significantly in muscle strength and flexibility (p<.05). Conclusion: This study showed that pelvic compression belts and Swiss ball exercise programs will help health improvements such as muscle strength, flexibility, and balance in normal adults, and it is also thought to be worth applying to patients with back pain.

• Journal of the Korean Society for Heat Treatment
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• v.37 no.1
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• pp.23-28
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• 2024

As global warming accelerates, the transportation industry is increasing the use of lightweight materials with the goal of reducing carbon emissions. Magnesium is a suitable material, but its poor formability limits its use, so research is needed to improve it. Rare-earth elements are known to effectively control texture development, but their high cost limits commercial. In this study, changes in microstructure and texture were investigated by adding Pb, which is expected to have a similar effect as rare-earth elements. The material used is Mg-15wt%Pb alloy. Initial specimens were obtained by rolling at 773 K to a rolling reduction of 25% and heat treatment. Afterwards, plane strain compression was performed at 723 K with a strain rate of 5×10^-2s^-1 and a strain of -0.4 to -1.0. As a result, recrystallized grains were formed within the microstructure, and the main component of the texture changed from (0,0) to (30,26). The maximum axial density was initially 10.01, but decreased to 4.23 after compression.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.38 no.10
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• pp.837-844
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• 2014

Automotive manufacturers have recently developed various technologies for improving fuel economy and satisfying enhanced emission regulations. The ultra-lean direct injection engine is a promising technology because it has the advantage of improving thermal efficiency through the deliberate control of ignition. A conventional LPG engine has been redesigned to an ultra-lean-burn LPG direct injection engine in order to adopt combustion system of ultra-lean-burn. This study is aimed at investigating the effect of a change in the compression ratio on the performance and emission characteristics of a lean-burn LPG engine. The fuel consumption, heat release rate, combustion pressure, and emission characteristics are estimated depending on changing the effect of compression ratio. When the compression ratio is increased, it is difficult to improve the fuel consumption owing to an unstable combustion state, but the total hydrocarbon and nitrogen oxide emissions are reduced.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.171-180
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• 2002

The effective and accurate data flow problem analysis uses the dominator tree and DJ graphs. The data flow problem solving is to safely reduce the flow graph to the dominator tree. The flow graph replaces a parse tree and used to accurately reduce either reducible or irreducible flow graph to the dominator tree. In this paper, in order to utilize Tarian's path compress algorithm, the Top node finding algorithm is suggested and the existing delay reduction algorithm is improved using Path compression. The delayed reduction a1gorithm using path compression actually compresses the pathway of the dominator tree by hoisting the node while reducing to delay the DJ graph. Realty, the suggested algorithm had hoisted nodes in 22% and had compressed path in 20%. The compressed dominator tree makes it possible to analyze the effective data flow analysis and brings the improved effect for the complexity of code optimization process with the node hoisting effect of code optimization process.