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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korean Society of Coastal and Ocean Engineers
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Journal DOI :
Korean Society of Coastal and Ocean Engineers
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Volume & Issues
Volume 16, Issue 4 - 00 2004
Volume 16, Issue 3 - 00 2004
Volume 16, Issue 2 - 00 2004
Volume 16, Issue 1 - 00 2004
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A Study of Wave Control by New Type Floating Breakwater
Kim, Do-Sam ; Lee, Gwang-Ho ; Choe, Nak-Hoon ; Yun, Hee-Myum ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 16, issue 1, 2004, Pages 1~9
In this study, several new types of floating breakwater are proposed according to the geometry of the vertical barrier and the existence of horizontal plate, and are compared to the steel floating breakwater adopted in Won-Jun fishing port and the performance of wave control is numerically investigated by using Green function method. From the numerical results, model attached the horizontal barrier under the vertical barrier is more efficient for reflection and transmission coefficient than the steel floating breakwater in Won-Jun fishing port. It is confirmed that the transmitted waves can be controlled efficiently by optimizing the length and distance of a vertical and horizontal barriers.
Investigation of Long-Term Shoreline Changes Using Aerial Images
Jung, Seung-Jin ; Kim, Kyu-Han ; Pyun, Chong-Kun ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 16, issue 1, 2004, Pages 10~17
In this paper, the affine transformation method that is more simpler compare with digital orthophoto method is used analyzed the long-term shoreline change, and accuracy estimation was carried out. As a result of this study, it was able to check that the shoreline change on Namhangjin coast had eroded significantly compare with the past. Moreover, as a result of accuracy estimation, it shows that the RMS error around shoreline was about 1-2 m. In consideration that maximum allowable error shown in aerial photogrammetry specification is within 2 m, therefore, analysis results of shoreline change using affine transformation method on aerial images is reliable.
Variation of Stress Concentration Ratio with Area Replacement Ratio for SCP-Reinforced Soils under Quay Wall
Kim, Yun-Tae ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 16, issue 1, 2004, Pages 18~26
In order to accelerate the rate of consolidation settlement, to reduce settlement, and to increase bearing capacity for soft ground under quay, sand compaction pile method (SCP) has usually been applied. SCP-reinforced ground is composite soil which consists of the sand pile and the surrounding soft soil. One of main important considerations in design and analysis for SCP-reinforced soils is stress concentration ratio according to area replacement ratio. In this paper, the numerical analysis was conducted to investigate characteristics of stress concentration ratio in composite ground. It was found that stress concentration ratio of composite ground is not constant as well as depends on several factors such as area replacement ratio, depth of soft soil, and consolidation process. The values of stress concentration ratio increase during loading stage due to stress transfer of composite soil, and reach up to 2.5~12 according to area replacement ratio at the end of construction. After the end of consolidation, however, these values are converged to 2.5 to 6.0 irrespective of area replacement ratio due to increase in effective stress of soft soil during consolidation process.
Calculation of Expected Sliding Distance of Concrete Caisson of Vertical Breakwater Considering Variability in Wave Direction
Hong, Su-Yeong ; Suh, Kyung-Deok ; Kweon, Hyeok-Min ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 16, issue 1, 2004, Pages 27~38
In this study, the reliability design method developed by Shimosako and Takahashi in 1999 for calculation of the expected sliding distance of the caisson of a vertical breakwater is extended to take into account the variability in wave direction such as directional spreading of waves, obliquity of the deep-water design principal wave direction from the shore-normal direction, and its variation about the design value. To calculate the transformation of random directional waves, the model developed by Kweon et al. in 1997 is used instead of Goda's model, which was developed in 1975 for unidirectional random waves normally incident to a straight coast with parallel depth contours and has been used by Shimosako and Takahashi. The effects of directional spreading and the variation of deep-water principal wave directions were minor compared with those of the obliquity of the deep-water design principal wave direction from the shore-normal direction, which tends to reduce the expected sliding distance as it increases. Especially when we used the field data in a part of east coast of Korea, considering the variability in wave directions reduced the expected sliding distance to about one third of that not considering the directional variability. Reducing the significant wave height calculated at the design site by 6% to correct the effect of wave refraction neglected in using Goda's model was found to be proper when the deep-water design principal wave direction is about 20 degrees. When it is smaller than 20 degrees, a value smaller than 6% should be used, or vice versa. When we designed the caisson with the expected sliding distance to be 30 ㎝, in the area of water depth of 25 m or smaller, we could reduce the caisson width by about 30% at the maximum compared with the deterministic design, even if we did not consider the variability in wave directions. When we used the field data in a part of east coast of Korea, considering the variability in wave directions reduced the necessary caisson width by about 10% at the maximum compared with that not considering the directional variability, and is needed a caisson width smaller than that of the deterministic design in the whole range of water depth considered (10-30m).
Study of the Construction of Marine GIS through the Development of Ship-Navigation System Based on the Precise Coordinate Analysis of GPS
Jang, Yong-Gu ; Mun, Du-Yeoul ; Jung, Beom-Seok ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 16, issue 1, 2004, Pages 39~46
In the GIS construction to land and sea in Korea, GIS construction on land was completed mostly for big cities by NGIS(National Geography Information System) business. However, Marine GIS being constructed by the National Oceanographic Research Institute is still constructing geography information and definition of attribute information and real condition. We have done researches to get maximized ripple effect linking GPS and Navigation techniques on GIS. GPS in accuracy is divided into navigation and precise surveying equipments. Now, GPS technology has been developed very much and with low price GPS equipments are being introduced. But costs on the GPS equipments are high yet. Therefore, the GPS equipment, for navigation can be substituted by cheap GPS equipments in a car or ship. In this paper, the authors developed algorithm to convert ellipsoid coordinate between WGS84 and Bessel ellipsoid and to analyze map projection between BESSEL ellipsoid and UTM plane coordinate system. And the author developed ship navigation system with cheap GPS equipments using algorithm of ellipsoid conversion and map projection. The authors proposed the necessity on constructing Internet GIS to manage many ships.
A Prediction System of SS Induced by Dredging
Jung, Tae-Sung ; Kim, Tae-Sik ; Kang, See-Whan ;
Journal of Korean Society of Coastal and Ocean Engineers, volume 16, issue 1, 2004, Pages 47~55
A SS prediction system using GUI in coastal region has been developed to predict the dispersion of the suspended sediments occurred by dredging. The prediction system uses a finite element hydrodynamic model to calculate water level and velocities and a random-walk particle tracking model to simulate SS dispersion. The system was applied to hindcast the tidal currents and SS concentrations in the Kunsan coastal waters. The simulated tidal currents showed good agreements with the observed currents. The transport model was verified for analytic solutions and field observation showing good agreements.