• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.135-143
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• 2008

During the last decades several devastating tsunamis have been occurred. Recently, there have been increasingly concerned about tsunamis around the Korean Peninsula since the 2004 Sumatra Tsunami occurred on December 26, 2004. In general, the Korean Peninsula is not safe against potential tsunami attacks. The 1983 Central East Sea Tsunami and the 1993 Hokkaido Tsunami caused considerable damage to the Eastern Part of the Peninsula. Thus, a prediction of damage due to tsunamis must be required at the Eastern Part of the Peninsula. In this study, numerical simulation of tsunamis at Pohang New Port, one of the most important ports in the Eastern Part of Korea, is conducted for three different tsunami events. Numerical simulation is focused on inundation on the port and run-down around an intake structure which supplies cooling water to the porthinterland. The computed results show that Pohang New Port is damaged by the most dangerous tsunami which can be generated in the East Sea. Thus, it is required to set up a counter-measure against tsunami attacks at Pohang New Port.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.6
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• pp.482-488
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• 2011

Seadike is a coastal structure constructed in the rear region of the foreshore to maximize its usability by preventing direct effect of wave. The expected construction field is determined under the design wave and tidal condition where minor wave overtopping is anticipated. Thus, the location of seadike is generally fixed at the highest site of the surrounding area with seadike crest height controlling the permissible range of wave overtopping volume. But a lot of times, frontal sand beach of the seadike continuously deforms due to incident waves, resulting failure in maintaining its initial slope. The erosion and deposition of the seadike front cause changes in the crest height and volume of wave overtopping and decrease in the setting depth of the seadike, which endangers seadike region as a result. In this study, the relation of local scouring and setting depth of the seadike front in the run-up region is examined by using 2D hydraulic model tests and numerical simulations by modified SBEACH model. As a result, the study learned that if appropriate boundary condition is applied to the modified SBEACH model, it is possible to create practical estimations on the local scouring at the seadike foot when erosive waves flow into the region.

• Journal of the Earthquake Engineering Society of Korea
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• v.7 no.1
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• pp.41-55
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• 2003

A dynamically-interfaced multi-grid finite difference model for simulation of tsunamis in the East Sea(Choi et al.) was established and further applied to produce detailed feature of coastal inundations along the whole eastern coast of Korea. The computational domain is composed of several sub-regions with different grid sizes connected in parallel of inclined directions with 16 innermost nested models. The innermost sub-region represents the coastal alignment reasonably well and has a grid size of about 30 meters. Numerical simulations have been performed in the framework of shallow-water equations(linear, as well as nonlinear) over the plane or spherical coordinate system, depending on the dimensions of the sub-region. Results of simulations show the general agreements with the observed data of run-up height for both tsunamis. The evolution of the distribution function of tsunami heights is studied numerically and it is shown that it tends to the log-normal curve for long distance from the source.

• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.585-593
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• 2011

The purpose of this study was to analyze, from a kinematical point of view, the high jump techniques of three women's high jump winners at the IAAF World Championships, Daegu 2011. The trends for the techniques of the world's top high jumpers were examined, with a view toward adapting these techniques to the physical characteristics of Korean women's high jumpers. It was valuable that Di Martino, who was the shortest in height, was able to win a medal by using a single arm swing take-off technique, along with a half flexed leading leg swing to attain a deep arch and clear the bar. This showed that the world's top athletes used jumping techniques with no decrease in the run-up velocity at the take-off. Furthermore, It appeared that the knee joint angle at take-off had a direct effect on the body position at take-off (H1).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.42-48
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• 2008

A system of risk assessment is developed by using the reliability analysis which evaluate quantitatively both stability and performance of sloped-coastal structures according to several scenarios of sea-level rise. By using reliability functions on armor unit and run-up, the probabilities of failure can be straightforwardly calculated with respect to several design parameters such as nominal diameter of armor unit, slope of coastal structure, and freeboard height. By comparing the results before and after sea-level rise, it may be possible to exactly assess some ranges of decrease of stability and performance of sloped-coastal structure with respect to sea-level rise. Therefore, it can also be possible to make a decision which parameters should be repaired or strengthened in order to maintain the original stability and performance of sloped-coastal structures. Finally, The present results may be useful for designing some kinds of new sloped-coastal structures including the effect of sea-level rise.

• Journal of Ocean Engineering and Technology
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• v.30 no.1
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• pp.44-50
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• 2016

An experimental study was performed to investigate the behavior of green water on a structure with a rectangular cross section under wave conditions, along with the flow characteristics in bubbly water flow. An experiment was conducted in a two-dimensional wave flume using an acrylic model (1/125) of FPSO BW Pioneer operating in the Gulf of Mexico under its design wave condition. The occurrence of green water, including its development, in front of the model was captured using a high-speed Charge Coupled Device (CCD) camera with the shadowgraph technique. Using consecutive images, the generation procedure for green water on the model was divided into five phases: flip through, air entrapment, wave run-up, wave overturning, and water shipping. In addition, the distinct water elevations of the green water were defined as the height of flip through, height of splashing jet, and height of freeboard exceedance, and showed a linear relationship with the incoming wave height.

• Journal of Families and Better Life
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• v.19 no.1
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• pp.131-142
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• 2001

This research is to understand the actual conditions of the degrees of housework share, the usage of kitchen equipments, the adjustments of residence, and community service to understand difficulties on housework that disabled homemakers can have, and to present possible copping strategies for homelife improvement of disabled homemakers. The major findings of this study can be summarized as follows : 1) Main difficulties are that the disabled homemakers feel when performing housework are the preparation of meals, doing dishes, doing laundry, cleaning up etc, which are the essential parts of ones homelife. 2) The result shows that having a rice cooker, a refrigerator, and a stove is a necessity for the disabled homemakers and that the degree of usage is pretty high. 3) Most of the disabled homemakers lack basic adjustments for the disabled in their residence such as the adjustments of the height of shelves. 4) Considering that they do not recognize community service for them, and most of them are not covered by any service, we can conclude that community service for disabled homemakers is not run enough.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1214-1221
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• 2011

It is an well-known fact that dynamic properties should be considered in design and maintenance of civil structures undergoing dynamic force such as rail track. For designing of the rail tack structures, dynamic properties of track bed soil such as shear modulus (G) and damping coefficients(D) obtained in small to medium range of shear strain must be known. In general, small size sample of D=5 cm and H=10cm has been used mostly for test convenience. However, ratio of largest particle diameter of the soil to sample diameter is very important and affects to the values of dynamic soil properties in track bed. In this study, an RC/TS test apparatus was built and was run for testing a medium size soil sample that can handle with compacted soil sample up to 10 cm diameter and 20 cm height.

• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.20-27
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• 2001

Recently numerical approaches for wave loads acting on the vertical caisson of breakwater, and resulting wave reflection and transmission coefficients have been performed. Although the numerical studies by Sulisz's(1997) and Kim et al.(2000) are suggested representatively, theoretical formulation for nonlinear wave pressure is not developed yet. And experimental results of Sulisz(1997) revealed that nonlinear uplift pressure on the caisson may be produced largely on the case of caisson founded on the high rubble mound. From the results of this study, the nonlinear theory for the uplift wave pressure acting on the caisson by applying boundary integral method of Green theorem is formulated, and also the characteristics of nonlinear uplift pressure and run-up height on the caisson are evaluated numerically, according to the variations of hydraulic properties of the rubble mound.

• Smart Structures and Systems
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• v.14 no.3
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• pp.367-376
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• 2014

Ambient vibration techniques are nowadays a very popular tool to assess dynamic properties of buildings. Due to its non destructive character, this method is particularly valuable, especially for health monitoring of historical monuments. The present ambient vibration experiment consists on the evaluation of vibration modes of a Medieval tower. Situated in Soncino (close to Cremona, in the Northern Italian region named Lombardia), the tower of 41.5 meters height has been monitored by seismometers located at different points inside the structure. Spectral ratios of the recorded ambient vibrations clearly identify a fundamental mode at about 1 Hz, with a slight difference in the two horizontal components. A second mode is also evidenced at approx 4-5 Hz, with a moderate degree of uncertainty. The records of a ML 4.4 earthquake, occurred during the monitoring period, confirm the information obtained by microtremor analysis. Daily variations of both 1st and 2nd mode were detected: these variations, of an amount up to 2%, seem to be well related with the temperature.