• Proceedings of the KSR Conference
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• 2005.11a
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• pp.418-423
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• 2005

In designing underground structure such as tunnels, estimating geotechnical characteristics of the ground is one of the most important and difficult tasks. In this paper, a methodology that can identify geotechnical parameters using only field-measured relative convergence displacements is presented. By using only relative convergence measurement data, inevitable errors in absolute convergence estimation can be avoided and in turn the parameter estimation process can be simplified. The methodology utilizes sensitivity relationship between static displacement measurements and geotechnical parameters. The feasibility and applicability of the proposed methodology is verified via a 3-d numerical example of a tunnel structure.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2002.11a
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• pp.315-320
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• 2002

Marketing ventilation fan 3 kinds been using in kitchen of apartment house into compensation discharge performance of contaminant measure. When propane gas burns by gas table, did waste heat into measurement compensation with carbon dioxide that it happens. In measured all type of exhaust fan, discharge performance of carbon dioxide and waste heat was high there are been much displacement. Among A, B, C three types, performance of A type exhaust fan was most superior and performance of C type exhaust fan was most poor

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.97-100
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• 2006

This study performed numerical analysis for obtaining optimal frequency and damping ratio of tuned mass damper (TMD) using 20 seismic loads measured at rock site. The structures of $1{\sim}2$ second natural period were considered, and optimal frequency and damping ratio were estimated for different mass ratio in terms of displacement and absolute acceleration response control. Numerical results showed that the values of the optimal parameters were different those from previous study by Hartog.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.1193-1195
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• 1996

For an automatic steering problem of vehicles, the main task is to keep a reference path with assumption that the displacement from the guideline can be measured by a sensor. In this paper, a sliding mode fuzzy logic controller design method is introduced and it shows highly enhanced performance in comparison with the other results. The method can be relatively simply implemented.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.9
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• pp.1733-1740
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• 2011

In this research, a MEMS vibratory gyroscope with dual-mass system in the sensing mode has been proposed to increase the stability of the device using wide bandwidth. A wide flat region between the two resonance peaks of the dual-mass system removes the need for a frequency matching typically required for single mass vibratory gyroscopes. Bandwidth, mass ratio, spring constant, and frequency response of the dual-mass system have been analyzed with MATLAB and ANSYS simulation. Designed first and second peaks of sensing mode are 5,917 and 8,210Hz, respectively. Driving mode resonance frequency of 7,180Hz was located in the flat region between the two resonance peaks of the sensing mode. The device is fabricated with anodically bonded silicon-on-glass substrate. The chip size is 6mm x 6mm and the thickness of the silicon device layer is $50{\mu}m$. Despite the driving mode resonance frequency decrease of 2.8kHz and frequency shift of 176Hz from the sensing mode due to fabrication imperfections, measured driving frequency was located within the bandwidth of sensing part, which validates the utilized dual-mass concept. Measured bandwidth was 768Hz. Sensitivity calculated with measured displacement of driving and sensing parts was 22.4aF/deg/sec. Measured slope of the sensing point was 0.008dB/Hz.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.25-29
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• 2006

The object of this study is to develop new examination techniques for measuring the O-ring deformation behavior under the pressure condition. The extrusion lengths measured from the computed tomography were in good agreement with the results that measured from non-contact laser displacement sensor. The deformed shapes of O-ring measured by the computed tomography and evaluated by the FEM agreed well with the extrusion length and the expanded diameter. But the contact widths of the O-ring and steel measured by the computed tomography were a little larger than the results of the FEM.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.2
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• pp.121-129
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• 2022

Density and sound speed contrasts (g and h, respectively), and swimming angle were measured for sandfish (Arctoscopus japonicus) without swimbladder. The density contrast was measured by the volume displacement method while the sound speed contrast was measured by the acoustic measurements of travel time (time-of-flight method). The swimming angle was measured by dividing it into daytime, nighttime, daytime feeding and nighttime feeding. The g was 1.001 to 1.067 with an average (± standard deviation) of 1.032 (± 0.017), and the h was 1.007 to 1.022 with an average (± standard deviation) of 1.015 (± 0.003). The swimming angles (mean ± standard deviation) were 16.8 ± 10.3° during the daytime, 1.9 ± 12.3° during the nighttime, 30.2 ± 12.6° in the daytime feeding and 35.0 ± 13.2° in the nighttime feeding. These results will provide important parameters input to calculate theoretical scattering models for estimating the acoustic target strength of sandfish.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1744-1746
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• 1999

In this paper, we give pressure stimulation into organic ultra thin films and detected the induced displacement current properties, and then manufacture a device under the accumulation condition. In processing of a device manufacture, we can see the process is good from the change of a surface pressure and transfer ratio of area per molecule of organic ultra thin films. The structure of manufactured device is MIM(Au/polyimide LB films/AU), the number of accumulated 19 layers. I-V characteristic of the device is measured from -5[V] to +5[V]. The maximum value of measured current is increased as the number of accumulated layers are decreased. The insulation of a thin film is better as the interval between electrodes is larger, and the insulation properties of a thin film is better as the distance between electrodes is larger.

• Geotechnical Engineering
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• v.12 no.3
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• pp.83-98
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• 1996

In this paper, the results of back analysis based on, the inverse method are presented. Using the field measurements obtained from the two different underground storage caverns in Korea during their construction, the deformation modulus and the initial in-situ stresses of the rock masses around the access tunnels are calculated. The finite element analysis is carried out by usinB these results as input parameters. The calculated displacements are compared with the measured ones.

• Tribology and Lubricants
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• v.20 no.5
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• pp.278-283
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• 2004

O-ring seal is widely used for sealing pressure vessels and oil containers in various applications of mechanical equipments. The doughnut shape of the O-ring is very important components in most of the system assembly of mechanical apparatus. This paper presents the sealing force of a pressurized perfluoroelastomer O-ring, which is very important contact seal in sealing the semiconductor equipment. The sealing pressure is measured by experimental method and analyzed numerically by using the non-linear MARC finite element program. The seal tester is made to measure the contact force and displacement of the O-ring with an automatic control system of the working temperature. The results show the reasonable agreements between the computed FEM results and measured ones when the operating temperature is moderate temperature. But the compared values between the computed and tested results show a difference because of the increased temperature, which is related to the non-linear parameter of the O-ring material.