• Journal of Ocean Engineering and Technology
• /
• v.22 no.4
• /
• pp.27-33
• /
• 2008

One of the central problems in astudy of the coastal surface wave environment is predicting the transformation of waves as they propagate toward the shore. The transformation is mainly due to the existence of obstacles, such as breakwaters and vertical cylinders. In general, the types of wave transformation can be classified as follows: wave diffraction, reflection, transmission, scattering, radiation, et al. This research dealtwith wave transmission and dissipation problems for two dimensional irregular waves and vertical circular cylinders. Using the unsteady mild slope equation, a numerical model was developed to calculate the reflection and transmission of regular waves from a multiple-row circular breakwater and vertical cylinders. In addition, hydraulic model experiments were conducted with different values for the properties between tire piles and the opening ratio (distances) between the rows of the breakwater. It was found that the transmission coefficients decreased with a decrease in the opening ratio and an increase in the rows of vertical cylinders. A comparison between the results of hydraulic and numerical experiments showed reasonable agreement.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.10 no.3
• /
• pp.71-78
• /
• 2007

We suggest a multi-path propagation analysis method using DTM(Digital Terrain Map). Generally, the total signal strength at a target is calculated by adding the field propagated in free space and the field reflected from the ground surface. In this paper, we also consider the vertical reflections associated with the vertical surfaces such as precipitous cliffs and electricity pylons in the mountain area. In addition, we primarily take account the main slope of the ground surface to improve the accuracy of the total field density at the target.

• Korean Journal of Applied Biomechanics
• /
• v.28 no.3
• /
• pp.165-173
• /
• 2018

Objective: The purpose of this study is to provide biomechanical basis data for the analysis of the maximum vertical ground reaction force, the maximum plantar pressure, the average plantar pressure, and the contact area according to the type of the insole through the insole insertion type foot pressure gauge. Method: In the treadmill, the slope was set at 10%, the first type A was worn at a walking speed of 3.5 km / h, and then walking was carried out using B, C, and D types. Data from 20 boots with consistent walking were extracted and plantar pressure data were collected and analyzed. Results: Functional insole was more effective than conventional insole for maximum vertical ground reaction force, maximum plantar pressure, average plantar pressure, and contact area at 10% of treadmill ramps. Conclusion: In this study, D-type insole supports the cushion in the middle part and supports the heel cup with hardness in the hind part, so that it is the most effective insole by lowering the plantar pressure and dispersing it more widely.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2000.11a
• /
• pp.193-200
• /
• 2000

Numerical analysis of slope stability is presented using slice method, static seismic analysis methods, and earthquake response analysis methods. Static seismic force is considered as 0.2g while vertical static seismic force is not considered in analysis. For earthquake response analysis, Hachinohe-wave is applied. Safety factor calculated using slice method for failure surface. Calculating methods are Bishop's method and Janhu's method. Static seismic analysis was applied using Mhor-Coulomb model and earthquake response analysis was applied using non-linear elastic model.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.318-318
• /
• 2010

In this paper, we studied generating characteristic of cymbal type piezoelectric transducer according to change of cymbal cap. The transducer is composed of circular piezoelectric ceramic and two elastic bodies which are shaped as cymbal. Two elastic bodies are attached to upper and bottom of the ceramic. Principle of the transducer is to generate expanded displacement because vertical stress is transformed into horizontal stress by slope angle of elastic bodies. The transducer also has advantage of high durability by the angle of elastic bodies. In this study, each parameter was chosen, and then generating characteristics were analyzed by FEM program. The parameters were slope angle of cymbal cap (theta), cap height (h) and cap inner diameter(d). The model that had generating characteristic Of high voltage was chosen by results of the analysis. Besides, maximum vertical displacements according to change of vertical stress were analyzed by structural analysis in order to find out relation between the maximum vertical stress which can prevent from ceramic damage and conditions of each cap.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.3
• /
• pp.321-327
• /
• 2013

Purpose: To investigate a correlation between vertical fixation disparity and stereopsis by analyzing distribution of types of vertical fixation disparity. Methods: In this study, RANDOT(R) stereotest partly using random dot was used in stereopsis tests. The vertical fixation disparity in close proximity categorized fixation disparity slope into six types on the basis of the result of measurement in when two thin lines, one for one eye looks, become overlapped as a line by adding into prism with Wesson fixation disparity card while maintaining a distance of 25 cm from patients. Results: In the types of near vertical fixation disparity curve, targeting 43 people, the first type 55.82% was the most distributed, the second type is the least 23.25%, the third type of 4.65%, the fourth type of 4.65%, the fifth type of 6.98%, the sixths types of 4.65% were distributed. The result of a correlation analysis, which shows the degree of linear correlation between two variables, represented that stereopsis is not correlated with Y-intercept (r = -0.07) which show vertical fixation disparity, associated phoria (r = -0.03) and dissociated phoria (r = -0.00), but it was not statistically significant (p>0.05). Fixation disparity slope of vertical fixation disparity (r = 0.36) was shown to have a positive correlation with stereopsis. It has a low positive correlation and a meaningful statistics (p<0.05). The Y-intercept which indicates vertical fixation disparity was also not associated with stereopsis (r = -0.07) and dissociated phoria (r = -0.03), and this was not statistically significant (p>0.05), while it had a high correlation as well as a statistically significant with associated phoria (r = 0.89). There was a negative correlation between Y-intercept and fixation disparity slope of vertical fixation disparity (r = -0.33). It showed a low relationship but statistically valuable (p>0.05). As a result of regression analysis, the stereopsis was changed as 7.631" if vertical fixation disparity changes 1' and the vertical fixation disparity changed as 0.017' if stereopsis changes 1', and the change was statistically significant (p<0.05). Conclusions: The study shows that there is a low correlation between stereopsis and vertical fixation disparity, and it is difficult to determine stereopsis only using vertical fixation disparity. Therefore, it suggests other factors above vertical fixation disparity have greater influence on stereopsis.

• International Journal of Highway Engineering
• /
• v.13 no.2
• /
• pp.125-131
• /
• 2011

This research aims to investigate the cause of the occurrence of a weak road drainage section scientifically and specifically through a site survey for a poorly drained section occurring due to rainfalls during road operation. This paper deeply reviewed the existing research results and current situation data on the poorly drained sections accumulated in Korea Expressway Corporation in order to investigate the cause of the occurrence of a weak road drainage section, and deeply verified and analyzed the weak sections for the road surface drainage facilities and the other road drainage facilities by visiting the expressway controlled by the 6 local headquarters and 33 branches of Korea Expressway Corporation. As a result of site surveys for the weak road drainage sections, i) in a road surface section, occurrence of ponding in the road shoulder pavement due to slope changes, bad collection of water in the collecting well at a median strip, shortage of road shoulder dike height, and inferior construction, etc. was analyzed to be the main cause of the occurrence of poorly drained sections, and ii) in a road neighborhood section, the occurrence of pavement height difference in a main road and shoulder section due to inferior ditches on a slope and the bad drain age at the inlet and outlet of a culvert due to soil deposits, debris, etc. were analyzed to be the main cause of the occurrence of weak sections. Proposed as a plan to improve the poorly drainage section of road were i)calculation of capacity through material changes at the ditch, enhancement of vertical sections and hydraulic analysis in terms of construction and other aspects, ii)derivation of a combined slope considering a slope and a vertical linearity and maintenance of proper distance between drainage structures in a vertical concave section in terms of geometrical structure, and iii)calculation of the drainage facility installation interval using a minutely rainfall intensity formula and a non-uniform flow analysis technique in terms of hydraulics and hydrologics and prompt removal of rainfalls from the road surface according to a linear drainage method.

• Korean Journal of Environment and Ecology
• /
• v.22 no.3
• /
• pp.268-279
• /
• 2008

This study is aimed at typifying the crossing structure and inquiring into the characteristics of vegetation distribution by type targeting Dorimcheon(stream), Banghakcheon(stream), Seongnaecheon(stream) and some sections of Yangjaecheon(stream) in Seoul through the establishment of basic data for restoring vegetation in urban stream. This research classified the crossing structure into 56 slope types and 31 vertical types in combination with the three items, such as bank slope(vertical style, slope style) of bank, absence or presence of waterside, and revetment structure. This research derived nine slope types including SB1 (revetment of low water level-revetment with vegetation, and revetment of high water level-nature riverside) including SG5(revetment of low water-concrete, and revetment of high water level-riprap work), and three vertical types, such as VH4(bank revetment-wet masonry), and VH7(bank revetment - concrete )from the target survey areas. Among these, both revetment of low water level and high water level were found to be distributed on the longest section as the type of SG7 and VG7 structured in concrete. As a result of inquiry and analysis of micro topography structure and vegetation structure of eight major types, this research could find out the influence of crossing structure on plant vegetation according to the characteristic by typified item, but there appeared no distinct characteristic of vegetation distribution by crossing structure.

• Journal of the Korean Society of Environmental Restoration Technology
• /
• v.14 no.5
• /
• pp.127-136
• /
• 2011

This study was conducted on the field application for a method which is currently used. Although the method was performed with experimental knowledge, this study attempted to approach scientific ways through thirty sets of test-bed and three times monitoring limited by control variations for three months. The factors on previous studies are slope location, slope degree, type (roadfill vs. roadcut), aspect, vegetation cover, species, thickness, vertical length, horizontal length, soil type, elevation, erosion, soil-moisture, soil-hardness, pH, and so on. However, the factors of a suitable and significant level are slope degree, type, aspect, thickness, soil-moisture, vertical length and horizontal length in slope revegetation. the results were as follows : As a result of survey on soil types based on the status before construction, the rate of vegetation cover with non-mesh construction in soil areas was better than the rate of vegetation cover with fiber meshes and wire meshes. The rate of vegetation cover with fiber meshes in weathered rocks was better than using wire meshes. The rate of vegetation cover with the wire meshes in blasted rocks was better than using fiber meshes. Also, the factors affecting the rate of vegetation cover presented the number of appearance species, soil-moisture, thickness. this result presented the more appearance species as a positive role, and the lower soil-moisture and the thicker soil as a negative role.

• Ocean and Polar Research
• /
• v.27 no.3
• /
• pp.277-288
• /
• 2005

Spatial distribution and vertical structures of water masses around the Antarctic continental margin are described using synthesized hydrographic data. Antarctic Surface Water (AASW) over the shelf regime is distinguished from underlying other water masses by the cut-off salinity, varying from approximately 34.35 to 34.45 around Antarctica. Shelf water, characterized by salinity greater than the cut-off salinity and potential temperature less than $-17^{\circ}C$, is observed on the Ross Sea, off George V Land, off Wilkes Land, the Amery Basin, and the Weddell Sea, but in some shelves AASW occupies the entire shelf. Lower Circumpolar Deep Water is present everywhere around the Antarctic oceanic regime and in some places it mixes with Shelf Water, producing Antarctic Slope Front Water (ASFW). ASFW, characterized by potential temperature less than about $0^{\circ}C$ and greater than $-17^{\circ}C$, and salinity greater than the cut-off salinity, is found everywhere around Antarctica except in the Bellingshausen-Amundsen sector. The presence of different water masses over the Antarctic shelves and shelf edges produces mainly three types of water mass stratifications: no significant meridional property gradient in the Bellingshausen and Amundsen Seas, single property gradient where ASFW presents, and a V-shaped front where Shelf Water exists.