Probability distribution of maximum earthquake magnitude is first derived for an unspecified probability distribution of earthquake magnitude. A model for energy release of large earthquakes, similar to that of Adler-Lomnitz and Lomnitz, is introduced from which the probability distribution of earthquake magnitude is obtained. An extensive set of world data for shallow earthquakes, covering the period from 1904 to 1980, is used to determine the parameters of the probability distribution of maximum earthquake magnitude. Because of the special form of probability distribution of earthquake magnitude, a simple iterative scheme is devised to facilitate the estimation of these parameters by the method of least-squares. The agreement between the empirical and derived probability distributions of maximum earthquake magnitude is excellent. 相似文献
In hydrosystem engineering design and analysis, temporal pattern for rainfall events of interest is often required. In this
paper, statistical cluster analysis of dimensionless rainfall pattern is applied to identify representative temporal rainfall
patterns typically occurred in Hong Kong Territory. For purpose of selecting an appropriate rainfall pattern in engineering
applications, factors affecting the occurrence of different rainfall patterns are examined by statistical contingency tables
analysis through which the inter-dependence of the occurrence frequency of rainfall patterns with respect to geographical
location, rainfall duration and depth, and seasonality is investigated. Furthermore, due to inherent variability of rainfall
mass curves or hyetographs within each classified rainfall pattern, a practical procedure to probabilistically generate plausible
rainfall patterns is described. The procedure preserves the inherent stochastic features of random dimensionless rainfall
hyetograph ordinates, which in general are correlated non-normal multivariate compositional variables. 相似文献
Enzyme induced carbonate precipitation (EICP) is an emerging soil improvement method using free urease enzyme for urea hydrolysis. This method has advantages over the commonly used microbially induced carbonate precipitation (MICP) process as it does not involve issues related to bio-safety. However, in terms of efficiency of calcium carbonate production, EICP is considered lower than that of MICP. In this paper, a high efficiency EICP method is proposed. The key of this new method is to adopt a one-phase injection of low pH solution strategy. In this so-called one-phase-low-pH method, EICP solution consisting of a mixture of urease solution of pH?=?6.5, urea and calcium chloride is injected into soil. The test results have shown that the one-phase-low-pH method can improve significantly the calcium conversion efficiency and the uniformity of calcium carbonate distribution in the sand samples as compared with the conventional two-phase EICP method. Furthermore, the unconfined compressive strength of sand treated using the one-phase-low-pH method is much higher than that using the two-phase method and the one-phase-low-pH method is also simpler and more efficient as it involves less number of injections.
The inverse problem of parameter structure identification in a distributed parameter system remains challenging. Identifying a more complex parameter structure requires more data. There is also the problem of over-parameterization. In this study, we propose a modified Tabu search for parameter structure identification. We embed an adjoint state procedure in the search process to improve the efficiency of the Tabu search. We use Voronoi tessellation for automatic parameterization to reduce the dimension of the distributed parameter. Additionally, a coarse-fine grid technique is applied to further improve the effectiveness and efficiency of the proposed methodology. To avoid over-parameterization, at each level of parameter complexity we calculate the residual error for parameter fitting, the parameter uncertainty error and a modified Akaike Information Criterion. To demonstrate the proposed methodology, we conduct numerical experiments with synthetic data that simulate both discrete hydraulic conductivity zones and a continuous hydraulic conductivity distribution. Our results indicate that the Tabu search allied with the adjoint state method significantly improves computational efficiency and effectiveness in solving the inverse problem of parameter structure identification. 相似文献
Energy and water are scarce resources and understanding the complicated energy–water nexus is an important issue for effective resource management. The purpose of this research was to analyze the competitive and cooperative relationships involving energy and water production and use. Specifically, tradeoff and integrated management of hydropower generation and water supplies are analyzed for energy–water systems. A Nash–Cournot model was established to analyze strategic behaviors among participants in energy–water systems. In the model, tradeoff analysis and integrated management of hydropower and water supplies were simulated for a reservoir system. In addition, hydropower and thermal power generation in competitive energy markets was examined. A case study of Dajia River reservoirs in the Tai-Chung and Chang-Hwa energy–water systems is presented. Dajia River is the second longest river in central Taiwan; the reservoirs system of Dajia River generates hydropower with installed capacity of 1150 MW. Strategic competitive and cooperative behaviors regarding energy–water linkage were quantified in the results. The results show that integrated management of hydropower and water supplies can increase renewable energy production, lower electricity equilibrium price, and decrease carbon dioxide emission. 相似文献
Lagoonal tidal inlets are a typical morphology of the Central Coast of Vietnam. Recently, navigation channels in these inlets have become increasingly threatened by siltation. This study analyses the relations between sediment distribution and transport trends (using the technique of Sediment Trend Analysis-STA■) in the lagoonal system of the De Gi inlet and then proposes appropriate countermeasures against sand deposition in the navigation channel. The STA identified three types of transport trends in the De Gi inlet, namely dynamic equilibrium, net accretion, and net erosion. Processes associated with the tidal prism have resulted in trends of sediment transport and deposition across the flood and ebb tidal shoals, which maintain a present cross-sectional area of about 1000m^2. However, longshore sediment transport from north to south resulting from northeast waves cause additional sand deposition in the channel. In addition, the effects of refraction associated with a nearby headland and jetty also increase sedimentation. These processes provide the main reasons for sediment deposition in the De Gi inlet. Short term and regular dredging helps to maintain the navigation channel. A system comprised of three jetties (north, south, and weir) is necessary to ensure the longterm cross-sectional stability of the navigation channel. 相似文献
International Journal of Earth Sciences - The South China Sea (SCS) is one of the classical example of a non-volcanic passive margin situated within three tectonic plates of the Eurasian,... 相似文献
This paper proposes a novel rough set approach to discover classification rules in real‐valued spatial data in general and remotely sensed data in particular. A knowledge induction process is formulated to select optimal decision rules with a minimal set of features necessary and sufficient for a remote sensing classification task. The approach first converts a real‐valued or integer‐valued decision system into an interval‐valued information system. A knowledge induction procedure is then formulated to discover all classification rules hidden in the information system. Two real‐life applications are made to verify and substantiate the conceptual arguments. It demonstrates that the proposed approach can effectively discover in remotely sensed data the optimal spectral bands and optimal rule set for a classification task. It is also capable of unraveling critical spectral band(s) discerning certain classes. The framework paves the road for data mining in mixed spatial databases consisting of qualitative and quantitative data. 相似文献