• Economic and Environmental Geology
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• v.48 no.5
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• pp.379-390
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• 2015

Multibeam backscatter strength is dependent not only on seafloor sediment facies but also on changed incidence angle due to the actual bottom slope. Therefore, the correction for actual bottom slope should be considered before the analysis of backscatter strength. This paper demonstrates the backscatter correction technique for the actual incidence angle and ensonified area. The target area is a part of the eastern Yellow Sea with water depths of 46~55 m. The area is located between the sand ridges and covered by large dunes with various bottom slopes. The dunes usually have the gentle slopes of about $1{\sim}3^{\circ}$, but show some steep slopes of $5{\sim}15^{\circ}$ on the crest. The backscatter strength values on the crest range from -34 to -23 dB, assuming that the bottom is flat. However, this study shows that the backscatter strength range was somewhat reduced (-32~-25 dB) after correction for actual bottom slope. In addition, the backscatter imagery was significantly improved; high and low backscatter strength values on the crest due to the actual bottom slope were normalized. The results demonstrate that the correction technique in this study is an effective tool for processing backscatter strength.

• Journal of Fashion Business
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• v.5 no.2
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• pp.105-115
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• 2001

When restoring a tomb of Songeun, Park Ik that damaged by typhoon in Kobubri, Chungdomyon, Mill Yang, Kyoung Nam in October 2000, a flower designed stone and fresco was discovered. Soneun Park Ik passed the civil service examination in Kongmin dynasty and was consecutively occupied Sajaedogam(司宰少監; regarded as one of second highest official rank). The fresco realistically depicts custom of ordinary people in end of Koryo, beginning of Chosun dynasty that it is considered as an important research material in study of ostumes. Therefore, this research intend to contribute to study of costumes in general public of Koryo that has insufficient study materials through study and analyze of costumes in the fresco with literature research. The number of figures in the fresco is presumed as 26-27 in all but clearly observed figures is only five women and four men and partly damaged figures are two men and two women. Women are worn relatively long yoo that can cover hip as an upper garment and Sang(裳) as trousers. The upper garments are all adjusted to right and has Jikryoung gik (straight collars) but there are strip attached collars or double collars among the Jikryoung gik. The length of Sang reaches to ankle and a waistband is trailed to below the knees. Most of hair are combed in the two sides and made a ring, moreover worn ceremonial coronet, which imply the ceremonial parade. Distinguished from the frescos of Koguryo, there are no women wearing Po(袍) also Yoo with Dae(帶) and without were coexisted. The mens costume is mainly appeared in two types. One(元) is Danryoungpo, Po with round collar and wearing a lozenge shaped crest with a brim, the other is Jikryoung Po, Po with straight collar, and wearing Ballib(拔笠), the latter is a costume of two man presumed as envoys. In the case of Danryoungpo, its length reached to ankle that shows decorum and in Jikryoungpo its length is below the knees that seem to offer practicality for envoys to guide a long journey. Both man and women are in decent cloth with a crest, which simple costume for ordinary people as a Chaksoopo that has comfortable length for movement and narrow sleeves. Songeun Park Ik actively worked under regency of One dynasty that influence of Mongol is seen in mans crest. There are some changes but including womens costume most of cloth are followed Korean traditional costume style.

• Journal of Dental Rehabilitation and Applied Science
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• v.18 no.4
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• pp.277-288
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• 2002

Seven finite element models were constructed in mandible having single screw-type implant fixture connected to the premolar superstructure, in order to evaluate how the length, diameter and platform shape of a screw-type fixture influence the stress in the supporting tissue around fixtures. Each finite element model was varied in terms of length, diameter, and platform shape of the fixture. In each model, 250N of vertical load was placed on the central pit of an occlusal plane and 250N of oblique load placed on the buccal cusp. The stress distribution in the supporting tissue and the other components was analysed using 2-dimensional finite element analysis and the maximum von Mises stress in each reference area was compared. Under lateral loading, the stress was larger at the abutment/fixture interface, and in the crestal bone, compared to the stress pattern under vertical loading. The amount of stress at the superstructure was similar regardless of the length, diameter and platform shape of a fixture. Around the longer fixture, the stress was decreased at the bone crest and subjacent cancellous bone and increased in the cancellous bone area apical to the fixture. Around the wider fixture, the stress was decreased at the abutment/fixture interface, and the bone crest and increased in the cancellous bone area apical to the fixture. Around the fixture having wider platform, less stress was produced at the abutment/fixture interface and the upper part of the cortical bone, compared to the fixture having standard platform. In conclusion, the stress distribution of the supporting tissue was affected by length, diameter, and platform shape of a fixture, and the fixture which was larger in diameter and length could reduce the stress in the supporting tissues at the bone-fixture interface and bone crest area.

• Geophysics and Geophysical Exploration
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• v.22 no.3
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• pp.99-106
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• 2019

Resistivity method has been used for the dam safety inspection and, for the convenience of fieldwork, two-dimensional (2D) resistivity data has been usually measured along the dam crest. However, since the dam has three-dimensional (3D) structure, 2D resistivity survey along the dam crest violates 2D assumption and 3D effects caused by 3D topography and material properties in the dam distort the inversion result of 2D resistivity data acquired along the dam crest. Furthermore, it is really hard to evaluate the 3D structure of the dam and 3D leakage pathway using 2D resistivity survey because 2D resistivity survey can provide only 2D resistivity section beneath the survey line. In this study, 3D resistivity survey was conducted at a dam in Korea. By comparing the results from 3D and 2D resistivity surveys, merit and demerits of 3D survey were investigated. Finally, it was confirmed that 3D survey can provide more accurate information about the dam status and 3D leakage pathway compared to the 2D survey. Therefore the 3D resistivity survey should be actively expanded for more accurate dam safety inspection even though more time and expense are required.

• The Journal of Engineering Geology
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• v.32 no.2
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• pp.209-219
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• 2022

To experimentally investigate the variation of soil characteristics in slope during rainfall and the shape of slope failure, the model test was performed using soil box and artificial rainfall simulator. The model test of slope formed by the homogenous sand was performed, and the saturation pattern in the model slope due to rainfall infiltration was observed. The slope model with the inclination of 35° was set up on the slope of 30°, and the rainfall intensity of 50 mm/hr was applied in the test. The soil depth of 35 cm was selected by considering the size of soil box, and the TDR (time domain reflectometry) sensors were installed at various depths to investigate the change of soil characteristics with time. As the result of model test, the slope model during rainfall was saturated from the soil surface to the subsurface, and from the toe part to the crest part due to rainfall infiltration. That is, the toe part of slope was firstly saturated by rainfall infiltration, and then due to continuous rainfall the saturation range was enlarged from the toe part to the crest part in the slope model. The failure of slope model was started at the toe part of slope and then enlarged to the crest part, which is called as the retrogressive failure. At the end of slope failure, the collapsed area increased rapidly. Also, the mode of slope failure was rotational. Meanwhile, the slope failure was occurred when the matric suction in the slope was reached to the air entry value (AEV) estimated in soil-water characteristic curve (SWCC).

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.3
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• pp.105-115
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• 2024

In coastal structure design incorporating revetments, the assessment of wave overtopping discharge relies on hydraulic model experiments. Numerous empirical formulas have been developed to predict overtopping discharge based on quantitative data from these experiments. Typically, for revetment structures aimed at mitigating wave overtopping, crest height is determined by considering the maximum amplitude of the design wave, resulting in a relatively high freeboard compared to wave heights. However, achieving complete prevention of all wave overtopping would require the crown wall to have substantial crest heights, rendering it economically impractical. Therefore, the concept of limiting discharge has been introduced in the design of revetment structures, aiming to restrict wave overtopping discharge to an acceptable level. Consequently, many coastal structures in real-world settings feature relatively lower freeboard heights than incident wave heights. This study investigated wave overtopping discharge on rubble-mound breakwaters with relatively low freeboard heights through hydraulic model experiments. Furthermore, it conducted a comparative analysis of the predictive capabilities of existing empirical formulas for estimating overtopping discharge using experimental data.

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.304-304
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.186-186
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.164-164
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• 2003

• Proceedings of the Korean Magnestics Society Conference
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• 2003.12a
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• pp.173-173
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• 2003