• Journal of Korean Port Research
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• v.10 no.1
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• pp.53-61
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• 1996

This paper describes the effect of wave control using submerged flat plate by the numerical calculation and the hydraulic model test. The boundary element method is used to develop a numerical solution for the flow field caused by monochromatic oblique waves incident upon an infinitely long, sumerged flat plate situated in arbitrary water depth. The effect of wave blocking is examined according to the change of length, submerged depth of flat plate and incident angles. Numerical results show that longer length, shallower submergence of flat plate and larger incident angles enhance the effect of wave blocking. To validate numerical analysis method, hydraulic model test was conducted in 2-D wave flume with 60 cm metal sheet. Reflected waves are extracted from water surface elevation in front of the location of a submerged plate by least square method with 3 wave gages. From comparing experimental results with numerical results, efficiency of numerical analysis method by this study could be confirmed well within wide ranges of wave frequencies.

• Journal of the Korean GEO-environmental Society
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• v.20 no.2
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• pp.59-67
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• 2019

Using the results from laboratory soil test, field vane test and piezocone penetration test, the engineering characteristics of the soft ground at east side of Gwangyang Port, which is located at south coast of Jeollanam-do, were investigated and optimal piezocone penetration test depth was derived to calculate piezocone factor. In this paper, the results of 61 laboratory soil tests, 226 times of field vane tests and 26 piezocone penetration tests were used. The result of laboratory soil test suggested that some physical properties such as specific gravity, moisture content, liquid limit and plastic index and others are higher than other south coast regions, meanwhile uniaxial compression strength, undrained shear strength, defined as mechanical property, appeared to be relatively small, distributed widely. According to the plastic chart, the ground was classified as high compressibility clay and low compressibility clay, mostly represent to Type 3 clay by Robertson (1990)'s classification chart. Piezocone factor was calculated by empirical method, based on the undrained shear strength which was obtained by the field vane test. According to the analysis with 3 different depth range, to set the appropriate measured depth range of piezocone penetration for comparation, using average value of the range of 5 times the vane length showed the highest correlation.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.151-158
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• 2000

The use of unconditionally stable implicit time integration techniques for pseudo-dynamic tests has been recently proposed and advanced by several researchers such as Thewalt and Mahin Nakashima and Shing. The developed implicit algorithms are based on a-Method of Hugest et al. In this paper a concise summary and explanation of implicit method for Pseudo dynamic test is presented. Especially The a-C method developed by shing at al. has been in-depth evaluated for this study. Important parameters of the a-C method have been analyzed by the simulation test.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.707-711
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• 1998

Ultrasonic test usually was used for defect detection, crack depth measurements and strength estimation of hardened concrete. The essence of the pulse velocity method is that the transition time of an ultrasonic longitudinal pulse is measured in concrete. Ultrasonic velocity was propagated to the age of concrete, made a radical change at that time when concrete was setted. This study which monitored the change in a concrete by ultrasonic test was performed to estimate initial setting and final setting.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.617-622
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• 2000

The use of unconditionally stable implicit time integration techniques for pseudo-dynamic test has been recently proposed and advanced by several researchers such as Thewalt and Mahin, Nakashima and Shing, etc. The developed implicit algorithms are based on the $\alpha$-Method of Huges et al. In this paper, a concise summary and explanation of implicit method for Pseudo dynamic tese is presented. Especially, The $\alpha$-C method developed by shing et al. has been in-depth evaluated for this study. Important parameters of the $\alpha$-C method have been analyzed by the simulation test.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10b
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• pp.743-748
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• 1998

As nation's infrastructure is getting old, nondestructive evaluation of existing structures and construction quality control are getting important. In this thesis, flaw detection techniques of concrete members with asphalt using impact echo test were introduced. This techniques are based on stress wave propagation. In this field impact echo test, As load is gradually increased, frequency is increased. From this change of frequency through impact echo test, we can detect that the crack of bridge ascends and what the depth of crack is.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.585-592
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• 2002

Discharge capacity of PBD is the most important factor of specification items to control any product of PBD. There is no standard specification for the PBD. Because the degree of discharge capacity is related to well resistance, install depth, maximum strain etc in the field. Discharge capacity test of PBD, permeability test of filter are conducted using PBD materials used in Korea. This paper proposes the critical discharge capacity for deep PBD under condition of non well resistance based upon their test and theoretical calculation. It was found that discharge capacity more than about 10 ㎤/sec is enough to undergo designing of deep PBD without well resistance.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.13 no.3
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• pp.97-109
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• 2005

A canard type aircraft, which has good wing stall and stall/spin-proof characteristics, is under development. The aircraft prototype has full-depth core sandwich type wing and fixed landing gear, and has been built for test flights. Newly developing aircraft will be equipped with retractable landing gear and conventional foam core sandwich laminate structures and multi-rib wings. In this study, we present the structural test procedure and result for aircraft Firefly.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.627-630
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• 2004

This paper investigates a study on the bending behavior of beam strengthened with CFS under repeated loading. The test specimen consisted of 20cm in width, 40cm in depth, and 15cm in CFS width. We find the strength decrease under repeated loading test comparing with the monotonic incremental loading test.

• Restorative Dentistry and Endodontics
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• v.29 no.5
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• pp.439-445
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• 2004

The purpose of this study was to evaluate the influence of plugger penetration depth on the apical extrusion of root canal sealer during root canal obturation with Continuous Wave of Condensation Technique. Root canals of forty extracted human teeth were divided into four groups and were prepared up to size 40 of 0.06 taper with ProFile. After drying. canals of three groups were filled with Continuous Wave of Condensation Technique with System $B^{TM}$ and different plugger penetration depths of 3. 5, and 7 mm from the apex. Canals of one group were filled with cold lateral compaction technique as a control. Canals were filled with non-standardized master gutta-percha cones and 0.02 mL of Sealapex. Apical extruded sealer was collected in a container and weighed. Data was analyzed with one-way ANOVA and Duncan's Multiple Range Test. 3 and 5 mm penetration depth groups in Continuous Wave of Condensation Technique showed significantly more extrusion of root canal sealer than 7 mm penetration depth group (p < 0.05). However, there was no significant difference between 7 mm depth group in Continuous Wave of Condensation Technique and cold lateral compaction group (p < 0.05). The result of this study demonstrates that deeper plugger penetration depth causes more extrusion of root canal sealer in root canal obturation by Continuous Wave of Condensation Technique. Therefore, special caution is needed when plugger penetration is deeper in the canal in Continuous Wave of Condensation Technique to minimize the amount of sealer extrusion beyond apex.