• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.310-312
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• 2019

Many technologies developed by the Fourth Industrial Revolution. These technologies are available to many users over the Web using the Web standard HTML5. As the content offered on the web increases, the number of users using the web increases and the importance of web speed increases. Because users expect the web page to load faster, as the web page loading speed increases, users will leave the page. That is, web page loading rates and page departure rates are proportional. Therefore, it is necessary to speed up web page loading by increasing the speed at which content is provided. In this paper, let's check through an experiment how it can be provided faster when providing images on the Web with regard to images that are one of the contents provided through the Web. Based on the results of these experiments, we want to identify faster ways to provider images over the web and provide images in that way to reduce page departure rates and provide more user-friendly services.

• KSTLE International Journal
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• v.4 no.2
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• pp.66-72
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• 2003

This paper presents the hydrodynamic effect by the journal speed, eccentricity and source positions in order to overcome the defects of air bearing such as low stiffness and damping coefficient. Choosing the two row source position of air bearing is different from existing investigations in the side of pressure distribution of air film because of the high speed of journal and the wedge effects by the eccentricity. These optimal choices of the two row source positions enable us to improve the performance of the film reaction force and loading force as making the high-speed spindle. In this paper, The pressure behavior in theory of air film in high speed region of journal according to the eccentricity of journal and the source positions analyzed. The theoretical analysis has been identified by experiments. The results of investigated characteristics may be applied to precision devices like ultra-precision grinding machine and ultra high-speed milling.

• Proceedings of the KSR Conference
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• 1999.11a
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• pp.415-422
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• 1999

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. Five series of test were conducted with varying the soil profile conditions including the ground level, type of soil, and the thickness of each soil layer. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to know the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• International Journal of Ocean System Engineering
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• v.2 no.3
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• pp.170-175
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• 2012

Currently, most logistics use containers. The construction of new port and high speed medium size container ship for the transportation of merchandise have become very important. The problem of ship stability is also important because of its direct influence on the loss of human life, ships, and merchandise. The stability of a container ship during its operation is not a large problem because it is well considered in the design process. However, the assessment of ship stability during container loading/unloading in port still depends on the expertise of experienced personnel. In this paper, a model based simulation system is introduced, which is able to assess ship stability during container loading/unloading, using ENVISION, a general purpose simulation system.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.4
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• pp.102-109
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• 2015

The methodology to calculate loads on the bearings of the gas-turbine engine is presented for design of high-speed bearing. Firstly, the loads on the bearings are formulated according to the force and moment equilibrium with gyroscopic moment in three-dimensional space. Afterward, operating loading conditions of the engine are presented by applying the Joint Service Specification Guide, and magnitudes of transient and steady bearing loads are estimated based on the operating conditions. The calculated loading conditions of the bearings will be used for the essential design boundaries for the detail structural design and rig test.

• Journal of the Korea Furniture Society
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• v.23 no.3
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• pp.290-297
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• 2012

Recently, interest in wooden construction have been growing by increasing needs and demands for eco-friendly and traditional wooden building(Hanok). Especially, Hanok has the technical development in manufacturing the mortise-tenon joint without fasteners(precut), so it could be called to modernization, industrialization and popularization. But the structural design and analysis of the structure were not regulated and had the difficulty to consider the variation of wooden member and to conduct the difficulty in the structural analysis and the design of the joint. In this study, the stiffness ratio of wooden mortise and tenon joint was evaluated according to the vertical loading, lintel and loading speed. The joint was distinguished in semi-rigid joint regardless of their factors. The stiffness ratio was 0.40 in vertical loading, 0.50 without vertical loading and 0.44 in horizontal loading with high speed. This study would be utilized to the structural analysis and design with structural analysis and design program.

• Journal of Biosystems Engineering
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• v.34 no.4
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• pp.220-227
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• 2009

In the process of oyster mushroom production, loading work of culture medium needs the most intensive labor power. Therefore, development of culture medium machine causes to reduce the manpower and cost. The main objective of this study is to develop the culture medium loading machine and investigate the optimal operation conditions and to evaluate the economic value of the machine. The results are summarized as follows: 1. Optimum transporting velocity of the conveyor was 0.61 m/s 2. Optimum speed of blower was 3183 rpm at the transporting velocity of 0.61 m/s with the loading quantity of 3.41 t/hr 3. Recommendable opening area ratio of pressure controller was 1/2 at the blower speed of 3183 rpm and the transporting velocity of 0.61 m/s 4. The break even point resulted in $240\;m^2$ of cultivating area compared to the method of with portable workbench, and $350\;m^2$ of cultivating area compared to the method of with a tractor and a truck.

• Safety and Health at Work
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• v.4 no.2
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• pp.105-110
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• 2013

Background: To determine the influence of lifting speed and type on peak and cumulative back compressive force (BCF) and shoulder moment (SM) loads during symmetric lifting. Another aim of the study was to compare static and dynamic lifting models. Methods: Ten male participants performed a floor-to-shoulder, floor-to-waist, and waist-to-shoulder lift at three different speeds [slow (0.34 m/s), medium (0.44 m/s), and fast (0.64 m/s)], and with two different loads [light (2.25 kg) and heavy (9 kg)]. Two-dimensional kinematics and kinetics were determined. A three-way repeated measures analysis of variance was used to calculate peak and cumulative loading of BCF and SM for light and heavy loads. Results: Peak BCF was significantly different between slow and fast lifting speeds (p < 0.001), with a mean difference of 20% between fast and slow lifts. The cumulative loading of BCF and SM was significantly different between fast and slow lifting speeds (p < 0.001), with mean differences ${\geq}80%$. Conclusion: Based on peak values, BCF is highest for fast speeds, but the BCF cumulative loading is highest for slow speeds, with the largest difference between fast and slow lifts. This may imply that a slow lifting speed is at least as hazardous as a fast lifting speed. It is important to consider the duration of lift when determining risks for back and shoulder injuries due to lifting and that peak values alone are likely not sufficient.

• Tribology and Lubricants
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• v.27 no.3
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• pp.140-146
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• 2011

A miniature pendular type impact testing machine was designed and developed, adopting a magnetic powder brake in order to investigate tensile and shear behavior of a small solder ball at high speed. In this testing system, the potential energy of the pendulum is transferred into the impact energy during its drop. Then, the impact energy is transmitted through the striker which is connected to the push rods to push the specimen for tensile loading. The tensile behavior of lead-free solder ball in diameter of 760 ${\mu}m$ was successfully investigated in a speed range of 0.15 m/s~1.25 m/s using this designed device. The maximum tensile strength of the solder joint decreases with the loading speed in the testing condition. The maximum tensile strength of the joint was 56 MPa in the low speed region.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.1
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• pp.45-53
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• 2014

For the time integration solution of the impulsive dynamic contact problem of high-speed rotating disks formulated by the finite element technique, the velocity and acceleration contact constraints as well as the displacement contact constraint are imposed for the numerical stability without spurious oscillations. The solution of the present technique is checked by the numerical simulation using the concentric high-speed rotating disks with the clearance and impulsive loading. It is shown that the almost steady state solution agrees with the corresponding analytical solution of the elasticity and that the differentiated constraints are crucial for the numerical stability of such high-speed contact problems of the disks under impulsive loading.