• Journal of the Korean Geotechnical Society
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• v.36 no.11
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• pp.51-60
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• 2020

Estimation of passive earth pressure is an important factor in anchor block, temporary retaining wall and support block of raker that resist lateral earth pressure. In practice, due to ease of use, it is common to estimate the earth pressure using the theory of Coulomb and Rankine, which assumes the failure plane as a straight line. However, the passive failure plane generated by friction between the wall surface and the soil forms a complex failure plane: a curve near the wall and a flat plane near the ground surface. In addition, the limit displacement where passive earth pressure is generated is larger compared to where the active earth pressure is generated. Thus, it is essential to calculate the passive earth pressure that occurs at the allowable displacement range in order to apply the passive earth pressure to the design for structural stability reasons. This study analyzed the mobilized passive earth pressured to various displacement ranges within the passive limit displacement range using the semi-empirical method considering the complex failure plane.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.1220-1226
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• 2007

As the industry of 21C has been developed, the gas industry has grown and it has not only the convenience but also the riskiness fer using. Especially, the energy and environment problems have been getting serious after the modern industry revolution. Therefore, the demand of gas as an eco-friendly energy source is getting increased. With the demand of gas, the installation and use of gas boiler is also increased, so human life injury by the waste gas(CO) of boiler goes on increasing every year. Therefore, we want to find out the harm to human body through the study on the concentration of CO by the length of the curved exhaust tube of boiler. The allowable concentration of CO is 50ppm. The length of the one-meter-three-curved tube after three minutes is applicable to 50ppm of the threshold limit values of CO. Also, five meters exceed the threshold limit values of CO after five minutes. Strangely, the concentration of CO is under the threshold limit values from two to four meters.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2534-2539
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• 2007

Launch vehicles are exposed to aerodynamic heating conditions while flying at high Mach numbers in the atmosphere. In this study aerodynamic heating test for fairing nose-cone was done using ATSF(Aerodynamic Thermal Simulation Facility) and Engineering Model for fairing. ATSF is a facility that can simulate given temperature profile using about 4,000 halogen heaters on fairing model. Aerodynamic heating profile is got from result of thermal analysis using MINIVER, Thermal Desktop and SINDA/FLUINT. After aerodynamic heat test, it is found that initial temperature of fairing inner surface and thickness of BMS has important effects on temperature of fairing inner surface. Also it is confirmed that maximum temperature of fairing nose-cone inner surface during flight is lower than allowable temperature limit. Later, thermal correlation between thermal analysis and experimental results will be done using aerodynamic heating test result

• Journal of the Korea Society of Computer and Information
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• v.22 no.2
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• pp.45-50
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• 2017

This paper proposes a novel resource allocation scheme which allows to guarantee the user-perceived service quality for various high-quality mobile multimedia service such as interactive game, tactile internet service, remote emergency medical service or remote disaster handling robot control to a certain level in the mobile networks. In our proposed scheme, Mean Opinion Score(MOS), which represents the degree of user satisfaction for perceived quality, is determined based on the delay limit allowable to each service. Moreover resources are allocated in consideration of this MOS. Simulation results show that our proposed scheme can decrease the outage probability in comparison with existing schemes Moreover it can increase the total throughput as well.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.227-232
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• 2002

This paper presents an algorithm for general 2D and 3D NURBS interpolation and deals with command generation for 3 axes milling machining, including the feedrate control in order to meet two limitations, a geometrical accuracy and a dynamic restriction. Both of the maximum chordal error and the maximum acceleration specified by machine parameter lead to limit the allowable feedrate on the curvature of NURBS tool path. So, motion commands at every sampling time are continuously generated by those two limitations and programmed feedrate. Simulation results of interpolating several NURBS curves show that proposed NURBS algorithm is favorable in the machining free-form curve

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.3
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• pp.356-363
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• 2013

Mechanical molding press which is used for transformation process during semiconductor manufacturing process has structural deformations by pressure. If these deformations have over limit range, life of the press itself can be reduced and it will be exerted on a bad effect for quality of the semiconductor. In this research, the main plates and links of a press are analyzed in relation to the structural deformations caused by pressure excluding thermal deformations. After modifying the modeling, the analysis is performed again to determine optimal design of the press, and this design is introduced to ensure that most of the stresses on the main plates are within safe allowable limits. As a result, an optimal design method for the structure is investigated to produce the desired pressure even when the size of the main structure is minimized.

• Wind and Structures
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• v.11 no.5
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• pp.391-411
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• 2008

A design procedure of stabilizing cable is proposed using buffeting analysis to stabilize the seesaw-like motion of the free cantilevered structure of a cable-stayed bridge during its construction. The bridge examined is a composite cable-stayed bridge having a main span length of 500 m. Based on the buffeting analysis, the stress in bare structure exceeded the allowable limit and a set of stabilizing cable was planned to mitigate the responses. The most efficient positions of the hold-down stabilizing cables were numerically investigated by means of an FE-based buffeting analysis and the required dimensions and pretension of the stabilizing cables were also calculated. The proposed stabilizing measure would be expected to secure the aerodynamic safety of a cantilevered structure under construction with considerable mitigation of buffeting responses.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.8
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• pp.633-638
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• 2002

We study how the missile autopilot with three loop acceleration structure is related to the aerodynamic characteristics. First, the relationships between the response characteristics of wingless-tail controlled missile and aerodynamics are derived. Next the maximum allowable performance limit of autopilot and the design direction for a missile shape are indicated using the property of zero. The method proposed in this paper may give a help to the missile autopilot system design and determination of the shape of aerodynamic. Also, the validity of proposed method is demonstrated via numerical example.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.402-405
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• 2006

Inner support regions of continuous steel and concrete composite bridge decks, transverse crackings are easely developed by tensile forces due to live loads and primary and secondary effects of concrete shrinkage. Since these cracks have an influence on the durability of bridge decks, crack width should be controlled within allowable limit values. Although crack width is a function of steel stress, bar diameter, bar spacing, etc, the current code for the amount of longitudinal reinforcements provides only one value of 2 percent of the concrete area. In order to investigate cracking bahaviors of composite girders with the variation of the longitudinal steel ratios, negative flexural tests are conducted on five composite girders and crack width and crack spacing are compared to ACI Code and Eurocode. Based on the test results, it is discussed the suitability of the current code for the longitudinal steel ratio.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.345-349
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• 2008

In this paper, environmental noise analysis was performed for large power plant and desalination plant. Ray tracing method was used to predict inside noise of turbine building. It is important to design the plant with the allowable noise level. To improve the accuracy, main noise sources were estimated based on the field data. As the results of analysis, it was concluded that noise levels slightly exceed the specified noise limit in turbine building inside. In order to reduce the noise level, adding sound-absorbing materials to inside wall of turbine building was suggested and verified with the confirmed analysis model.