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Pile foundations that support transmission towers or offshore structures are dominantly subjected to cyclic lateral load induced by wind and waves. For a successful design, it is crucial to investigate the effect of cyclic lateral loads on the pile behavior that is loaded laterally. Although the p–y curve method is generally utilized to design the cyclic laterally loaded pile foundations, the effect of cyclic lateral loads on the pile has not been properly implemented with the p–y curve. This reflects a lack of consideration of the overall stiffness change in soil–pile interaction. To address this, a series of model pile tests were conducted in this study on a preinstalled aluminum flexible pile under various sandy soil conditions. The test results were used to investigate the effect of cyclic lateral loads on the p–y behavior. The cyclic p–y curve, which properly takes into account this effect, was developed as a hyperbolic function. Pseudo-static analysis was also conducted with the proposed cyclic p–y curve, which showed that it was able to properly simulate cyclic laterally loaded pile behavior in sandy soil. 相似文献
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Jeong-Hui Kim Sang-Hyeon Park Seung-Ho Baek Min-Ho Jang Ju-Duk Yoon 《Ocean Science Journal》2020,55(1):129-142
In the Saemangeum area, construction of a dike began in 1991 and was completed in 2006; desalination is currently being conducted. In order to investigate 相似文献
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Young Baek Son Joji Ishizaka Jong-Chul Jeong Hyun-Choel Kim Taehee Lee 《Ocean Science Journal》2011,46(4):239-263
To distinguish true red tide water (particularly Cochlodinium polykrikoides blooms) from non-red tide water (false satellite high chlorophyll water) in the South Sea of Korea, we developed a systematic
classification method using spectral information from MODIS level products and applied it to five different harmful algal
bloom events. Red tide and nonred tide waters were classified based on four different criteria. The first step revealed that
the radiance peaks of potential red tide water occurred at 555 and 678 nm. The second step separated optically different waters
that were influenced by relatively low and high contributions of colored dissolved organic matter (CDOM) (including detritus)
to chlorophyll. The third and fourth steps discriminated red tide water from non-red tide water based on the blue-to-green
ratio in areas with lower and higher contributions of CDOM to chlorophyll, respectively. After applying the red tide classification
(using the four criteria), the spectral response of the red tide water, which is influenced by pigment concentration, showed
different slopes for the blue and green bands (lower slope at blue bands and higher slope at green bands). The opposite result
was found for non-red tide water, due to decreasing phytoplankton absorption and increasing detritus/CDOM absorption at blue
bands. The results were well matched with the discoloration of water (blue to dark red/brown) and delineated the areal coverage
of C. polykrikoides blooms, revealing the nature of spatial and temporal variations in red tides. This simple spectral classification method
led to increase user accuracy for C. polykrikoides and non-red tide blooms (>46% and >97%) and provided a more reliable and robust identification of red tides over a wide range
of oceanic environments than was possible using chlorophyll a concentration, chlorophyll anomaly, fluorescence analysis, or proposed red tide detection algorithms. 相似文献
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Hyungwon Shim Bong-Huan Jun Pan-Mook Lee Hyuk Baek Jihong Lee 《Ocean Engineering》2010,37(11-12):1036-1047
This paper presents a control technique for structured undersea tasks that require a high degree of precision. The overall efficiency of tele-operated underwater manipulation is improved by reducing the burden on the human operator. A new workspace-control system composed of a computer and input devices in workspace was developed to support the operator. The computer transforms the desired velocity of end-effector in workspaces to desired joint angles by solving the inverse kinematics of the slave manipulators. The desired joint angles are transferred to the slave controller through RS-485 serial communication, and be followed by the slave manipulator. The developed master system provides advantages in conducting structured tasks(coring, drilling, underwater connector mating, etc.) that require precise control of the end-effector’s motion and attitude. The existing master system, however, is more useful for unstructured tasks than newly developed master system. By combining the two master systems, the work efficiency of the underwater tele-operated manipulator system was improved. This paper presents the development of the workspace-control system and a working strategy to alleviate operator’s burden in underwater works. Experimental results are presented to evaluate the effectiveness of the proposed method using underwater manipulators mounted on the KORDI deep-sea ROV Hemire. 相似文献
5.
Climate change in the 21st century simulated by HadGEM2-AO under representative concentration pathways 总被引：2，自引：0，他引：2
Hee-Jeong Baek Johan Lee Hyo-Shin Lee Yu-Kyung Hyun ChunHo Cho Won-Tae Kwon Charline Marzin Sun-Yeong Gan Min-Ji Kim Da-Hee Choi Jonghwa Lee Jaeho Lee Kyung-On Boo Hyun-Suk Kang Young-Hwa Byun 《Asia-Pacific Journal of Atmospheric Sciences》2013,49(5):603-618
We present climate responses of Representative Concentration Pathways (RCPs) using the coupled climate model HadGEM2-AO for the Coupled Model Intercomparison Project phase 5 (CMIP5). The RCPs are selected as standard scenarios for the IPCC Fifth Assessment Report and these scenarios include time paths for emissions and concentrations of greenhouse gas and aerosols and land-use/land cover. The global average warming and precipitation increases for the last 20 years of the 21st century relative to the period 1986-2005 are +1.1°C/+2.1% for RCP2.6, +2.4°C/+4.0% for RCP4.5, +2.5°C/+3.3% for RCP6.0 and +4.1°C/+4.6% for RCP8.5, respectively. The climate response on RCP 2.6 scenario meets the UN Copenhagen Accord to limit global warming within two degrees at the end of 21st century, the mitigation effect is about 3°C between RCP2.6 and RCP8.5. The projected precipitation changes over the 21st century are expected to increase in tropical regions and at high latitudes, and decrease in subtropical regions associated with projected poleward expansions of the Hadley cell. Total soil moisture change is projected to decrease in northern hemisphere high latitudes and increase in central Africa and Asia whereas near-surface soil moisture tends to decrease in most areas according to the warming and evaporation increase. The trend and magnitude of future climate extremes are also projected to increase in proportion to radiative forcing of RCPs. For RCP 8.5, at the end of the summer season the Arctic is projected to be free of sea ice. 相似文献
6.
Jieun Baek 《International journal of geographical information science》2017,31(11):2234-2254
We developed a least-cost path analysis algorithm that satisfies a slope threshold condition in hilly terrain. The new algorithm uses an expanding moving-window to explore a combination of cells that satisfy an elevation threshold condition and then supplements this by executing cut and fill operations when there are obstacle cells between source and destination cells. Cut and fill factors regarding the difference in the actual elevation and revised elevation are considered and a least-cost path is analyzed after calculating the accumulated travel cost to the destination point. After applying the developed algorithm to synthetic and real-world data, the least accumulated travel cost from the source point can then be calculated for all cells on the raster surface by considering various slope thresholds, moving-window sizes and raster data resolutions. This algorithm can be implemented as a useful tool in GIS software as well as engineering design software utilized in the construction and mining industries. 相似文献
7.
Assimilation of Hourly Surface Observations with the Canadian High-Resolution Ensemble Kalman Filter
An hourly-cycling ensemble Kalman filter (EnKF) working at 2.5?km horizontal grid spacing is implemented over southern Ontario (Canada) to assimilate Meteorological Terminal Aviation Routine Weather Reports (METARs) in addition to the observations assimilated operationally at the Canadian Meteorological Centre. This high-resolution EnKF (HREnKF) system employs ensemble land analyses and perturbed roughness length to prevent an ensemble spread that is too small near the surface. The HREnKF then performs continuously for a four-day period, from which twelve-hour ensemble forecasts are launched every six hours. The impact on analyses and short-term forecasts of assimilating METAR data is given special attention.It is shown that using ensemble land surface analyses increases near-surface ensemble spreads for temperature and specific humidity. Perturbing roughness length enlarges the spread for surface wind. Given sufficient ensemble spread, the four-day case study shows that the near-surface model state is brought closer to surface observations during the cycling process. The impact of assimilating surface data can also be seen at higher levels by using aircraft reports for verification. The ensemble forecast verification suggests that METAR data assimilation improves ensemble forecasts of air temperature and dewpoint near the surface up to a lead time of six hours or even longer. However, only minor improvement is found in surface wind forecasts. 相似文献
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Sang-konKim Maeng-eonPark Seung-gyunBaek Kyu-youlSung Sun-okKim Hee-yulPark 《东北亚地学研究》2004,7(2):125-135
Chemical composition, Raman microspectrometry, and Fourier transform infrared (FT-1R) and SEM-CL (Cathodluminescence) analyses are carried out for Tanzania and Madagascar garnets for locality identification. Inclusion study was sustained after electron probe microanalysis (EPMA). Needle-like illmenites, apatites and zircons were the most common solid inclusions in Tanzania garnets. Madagascar garnets revealed rutile needles and apatites were also observed, but differences in size, shape and distribution patterns were noticed compared to Tanzania garnets. Tanzania garnets exhibited all types of observable fluid inclusions such as ““ fingerprint““ pattern, called Type Ⅰ-A, liquid-only (L) single phase fluid inclusion, called Type Ⅰ-B and Type Ⅱ-A ( L S), Type Ⅱ-B ( L V) and Type Ⅲ-A (L Sylvite even if all examined garnets from three localities retained ““fingerprint““ features, so called, partially healed fractures, in common. Chemical composition, Raman microspectrometry and Fourier transform infrared (FT-IR) analysis taken turned out to be useful methods for the purpose of this study. Using consequences of SEM-CL and inclusion study, accordingly, the locality identification of gem-quality garnets is capable of being available in further application for other kinds of gemstones. 相似文献