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排序方式: 共有335条查询结果,搜索用时 15 毫秒
91.
Eun-Soo Hong Tae-Hyuk Kwon Ki-Il Song Gye-Chun Cho 《Rock Mechanics and Rock Engineering》2016,49(1):3-17
The present study explores the degradation characteristics and scale of unevenness (small-scale roughness) on sheared rock joint surfaces at a low-stress regime. While the degradation characteristics of unevenness and the normal stress are mutually interrelated, an understanding of the degradation patterns of the three-dimensional roughness of rock joints is one of the important components needed to identify asperity failure characteristics and to quantify the role of damaged unevenness in establishing a shear strength model. A series of direct shear tests was performed on three-dimensional artificial rock joint surfaces at different normal stress levels. After shearing, the spatial distributions and statistical parameters of degraded roughness were analysed for the different normal stress levels. The length and area of the degraded zones showed bell-shaped distributions in a logarithmic scale, and the dominant scale (or the most frequently occurring scale) of the damaged asperities (i.e., unevenness) ranged from approximately, 0.5 to 5.0 mm in length and 0.1–10 mm2 in area. This scale of the damaged unevenness was consistent regardless of the level of normal stress. It was also found that the relative area of damaged unevenness on a given joint area, and thus the contribution of the mechanical asperity failure component to shear strength increased as normal stress increased. 相似文献
92.
The tsunamis that have occurred in many places around the world over the past decades have taken a heavy toll on human lives and property. The eastern coast of the Korean Peninsula is not safe from tsunamis and has sustained tsunami damage in the past. The aim of this study is to review the past, present, and future of some aspects of tsunami research in Korea. A composite numerical model comprising propagation and inundation models is described. The paper also covers tsunami mitigation efforts in Korea, and a tsunami hazard map is developed and introduced. 相似文献
93.
Jinik Hwang So Yun Park Mirye Park Sukchan Lee Yeonhwa Jo Won Kyong Cho Taek-Kyun Lee 《Ocean Science Journal》2016,51(4):599-612
In this study, seawater samples were collected from Goseong Bay, Korea in March 2014 and viral populations were examined by metagenomics assembly. Enrichment of marine viral particles using FeCl3 followed by next-generation sequencing produced numerous sequences. De novo assembly and BLAST search showed that most of the obtained contigs were unknown sequences and only 0.74% of sequences were associated with known viruses. As a result, 138 viruses, including bacteriophages (87%), viruses infecting algae and others (13%) were identified. The identified 138 viruses were divided into 11 orders, 14 families, 34 genera, and 133 species. The dominant viruses were Pelagibacter phage HTVC010P and Roseobacter phage SIO1. The viruses infecting algae, including the Ostreococcus species, accounted for 9.4% of total identified viruses. In addition, we identified pathogenic herpes viruses infecting fishes and giant viruses infecting parasitic acanthamoeba species. This is a comprehensive study to reveal the viral populations in the Goseong Bay using metagenomics. The information associated with the marine viral community in Goseong Bay, Korea will be useful for comparative analysis in other marine viral communities. 相似文献
94.
Abnormally high-priced transactions in urban land speculation bring detrimental effects on economy, environment, and society. Governmental agencies around the world are striving hard to monitor and control land speculation by introducing various policy objectives and tools for an efficient urban development planning. One of the major challenges in controlling land speculation is to quickly identify the spatiotemporal locations of concern (hot spots) by monitoring the spatial clustering pattern changes over time and to alert the appropriate decision-making agencies for timely policy intervention. In this paper, we introduce a framework to rapidly detect the spatiotemporal hot spots of speculative land transactions in near-real-time data by exploiting the prospective monitoring procedures. We applied this method in the city of Hwasung, Republic of Korea, as an empirical illustration and found that the locations Jeongnam, Bongdam, Mado, and Dongtan were identified as hot spots with high, concentrated transaction values. The results indicate that the proposed framework is a capable tool for capturing prospective temporal indicators and pinpointing the localities of land speculation. 相似文献
95.
Hydroelastic response of a very large floating structure over a variable bottom topography 总被引:1,自引:0,他引:1
Jo Hyun Kyoung Sa Young Hong Byoung Wan Kim Seok Kyu Cho 《Ocean Engineering》2005,32(17-18):2040-2052
An influence of sea-bottom topography on the hydroelastic response of a Very Large Floating Structure (VLFS) is considered. When the floating structure is constructed near the shore, the sea-bottom topographical effect should be considered. In this study, the effect of sea-bottom topography is investigated for four different bottom cases. To calculate the sea-bottom effects rigorously, the finite-element method based on the variational formulation is used in the fluid domain. The pontoon-type floating structure is modeled as the Kirchhoff plate. The mode superposition method is adopted for the hydroelastic behavior of the floating structure. 相似文献
96.
Leandra Cho 《Ocean & Coastal Management》2005,48(11-12):932
Management of the Belize Barrier Reef was originally envisioned through the creation of marine protected areas. However, the influence of land-based activities was not accounted for in Marine Protected Area (MPA) programs. Therefore focus was shifted to an integrated approach via Integrated Coastal Management (ICM). The Belize ICM process has evolved into a system of coordination through the fostering of multi-sectoral linkages for integrated management of coastal resources. Marine protected areas were included in the ICM program as tools for achieving biodiversity protection and management of sensitive habitats. The ICM process has resulted in greater coordination and consultation in decision making for coastal resource issues, the MPA program however has not evolved with the trend of greater community involvement in MPA management. The greatest challenges to MPA and ICM programs in the next 10 years are: improved linkages between the two, fostering of community participation in management, broadening of the scope of ICM to watersheds and ocean governance, and sustainable financing for both programs. 相似文献
97.
The Saemanguem Reclamation Project proposed building a 33 km dike, to reclaim 28,300 ha of wetlands and estuary for rice production. In addition, the project would store 530 million tons of freshwater in the estuary for agriculture. The time frame for this construction was 21 years from 1991 to 2011 with a budget of US $2.1 billion. During the project, another reclamation project, called the “Shiwha Reclamation Project,” which was established between 1987 and 1994, was written off as a failure and an environmental disaster. The public started to recognize the value of wetlands and coastal waters and has strongly opposed the Saemanguem Reclamation Project. However, the voices of supporters for the project were also strong, so its resolution was controversial. This article analyzes the evolution and solution of conflicts among stakeholders and discusses some lessons applicable to large reclamation projects. 相似文献
98.
A numerical model describing the propagation and run-up process of nearshore tsunamis in the vicinity of shorelines is developed based on an approximate Riemann solver. The governing equations of the model are the nonlinear shallow-water equations. The governing equations are discretized explicitly by using a finite volume method. The nonlinear terms in the momentum equations are solved with the Harten-Lax-van Leer-Contact (HLLC) approximate Riemann solver. The developed model is first applied to prediction of water motions in a parabolic basin, and propagation and subsequent run-up process of nearshore tsunamis around a circular island. Computed results are then compared with available analytical solutions and laboratory measurements. Very reasonable agreements are observed. 相似文献
99.
In this paper, image processing technique that reduces video images of buoy motion to yield time series of image coordinates
of buoy objects will be investigated. The buoy motion images are noisy due to time-varying brightness as well as non-uniform
background illumination. The occurrence of boats, wakes, and wind-induced white caps interferes significantly in recognition
of buoy objects. Thus, semiautomated procedures consisting of object recognition and image measurement aspects will be conducted.
These offer more satisfactory results than a manual process. Spectral analysis shows that the image coordinates of buoy objects
represent wave motion well, indicating its usefulness in the analysis of wave characteristics. 相似文献
100.
ABSTRACTA hybrid hydrologic model (Distributed-Clark), which is a lumped conceptual and distributed feature model, was developed based on the combined concept of Clark’s unit hydrograph and its spatial decomposition methods, incorporating refined spatially variable flow dynamics to implement hydrological simulation for spatially distributed rainfall–runoff flow. In Distributed-Clark, the Soil Conservation Service (SCS) curve number method is utilized to estimate spatially distributed runoff depth and a set of separated unit hydrographs is used for runoff routing to obtain a direct runoff flow hydrograph. Case studies (four watersheds in the central part of the USA) using spatially distributed (Thiessen polygon-based) rainfall data of storm events were used to evaluate the model performance. Results demonstrate relatively good fit to observed streamflow, with a Nash-Sutcliffe efficiency (ENS) of 0.84 and coefficient of determination (R2) of 0.86, as well as a better fit in comparison with outputs of spatially averaged rainfall data simulations for two models including HEC-HMS. 相似文献