This paper presents a continuous version of the model of distribution dynamics to analyse the transition dynamics and implied
long-run behaviour of the EU-27 NUTS-2 regions over the period 1995–2003. It departs from previous research in two respects:
first, by introducing kernel estimation and three-dimensional stacked conditional density plots as well as highest density regions
plots for the visualisation of the transition function, based on Hyndman et al. (J Comput Graph Stat 5(4):315–336, 1996), and second, by combining Getis’ spatial filtering view with kernel estimation to explicitly account for the spatial dimension of the
growth process. The results of the analysis indicate a very slow catching-up of the poorest regions with the richer ones,
a process of shifting away of a small group of very rich regions, and highlight the importance of geography in understanding
regional income distribution dynamics.
This paper proposes a novel history-matching method where reservoir structure is inverted from dynamic fluid flow response.
The proposed workflow consists of searching for models that match production history from a large set of prior structural
model realizations. This prior set represents the reservoir structural uncertainty because of interpretation uncertainty on
seismic sections. To make such a search effective, we introduce a parameter space defined with a “similarity distance” for
accommodating this large set of realizations. The inverse solutions are found using a stochastic search method. Realistic
reservoir examples are presented to prove the applicability of the proposed method. 相似文献
Any calculation of seismic wave propagation comprising the seismic source, the travel path, and the receiver site in a single finite-difference (FD) model requires a considerable amount of computer time and memory. Moreover, the methods currently available for including point sources in the 2D FD calculations are far-field approximations only. Therefore we have developed a new hybrid method for treating the seismic wave fields at localized 2D near-surface structures embedded in a 1D background medium, and excited by a point source. The source radiation and propagation in the background model is solved by the discrete-wave number (DW) method, while the propagation in the local 2D structure is calculated by the FD method. The coupling between the two sets of calculations is performed on a rectangular excitation box surrounding the local structure. We show the usefulness of the method in ground-motion studies where both near-field source effects and local site effects are important. Technical problems connected with the inconsistency between the 3D source radiation and the 2D FD calculation are minor for the relatively distant in-plane point explosive sources, but are more serious for the in-plane dislocation sources. 相似文献
Weak and strong ground motions were numerically predicted for three stations of the Ashigara Valley test site. The prediction was based on the records from a rock-outcrop station, one weak-motion record from a surface-sediments station, and the standard geotechnical model. The data were provided by the Japanese Working Group on the Effects of Surface Geology as a part of an international experiment. The finite-difference method for SH waves in a 2-D linear viscoelastic medium (a causalQ model) was employed.Comparison with the real records shows that at two stations the predictions fit better than at the third one. Strangely, the two better predictions were for stations situated at larger distances from the reference rock station (one station was on the surface, the other in a borehole). The strong ground motion (the peak acceleration of about 200 cm s–2) was not predicted qualitatively worse than the weak motion (8 cm s–2). A less sophisticated second prediction (not submitted during the experiment), in which we did not attempt to fit the available weak-motion record at the sedimentary station, agrees with the reality significantly better. 相似文献
This paper presents results recently obtained for generating site-specific ground motions needed for design of critical facilities. The general approach followed in developing these ground motions using either deterministic or probabilistic criteria is specification of motions for rock outcrop or very firm soil conditions followed by adjustments for site-specific conditions. Central issues in this process include development of appropriate attenuation relations and their uncertainties, differences in expected motions between Western and Eastern North America, and incorporation of site-specific adjustments that maintain the same hazard level as the control motions, while incorporating uncertainties in local dynamic material properties. For tectonically active regions, such as the Western United States (WUS), sufficient strong motion data exist to constrain empirical attenuation relations for M up to about 7 and for distances greater than about 10–15 km. Motions for larger magnitudes and closer distances are largely driven by extrapolations of empirical relations and uncertainties need to be substantially increased for these cases.
For the Eastern United States (CEUS), due to the paucity of strong motion data for cratonic regions worldwide, estimation of strong ground motions for engineering design is based entirely on calibrated models. The models are usually calibrated and validated in the WUS where sufficient strong motion data are available and then recalibrated for applications to the CEUS. Recalibration generally entails revising parameters based on available CEUS ground motion data as well as indirect inferences through intensity observations. Known differences in model parameters such as crustal structure between WUS and CEUS are generally accommodated as well. These procedures are examined and discussed. 相似文献
This paper presents the extension of the self-calibrating method to the coupled inverse modelling of groundwater flow and mass transport. The method generates equally likely solutions to the inverse problem that display the variability as observed in the field and are not affected by a linearisation of the state equations. Conditioning to the state variables is measured by an objective function including, among others, the mismatch between the simulated and measured concentrations. Conditioning is achieved by minimising the objective function by gradient-based methods. The gradient contains the partial derivatives of the objective function with respect to: log conductivities, log storativities, prescribed heads at boundaries, retardation coefficients and mass sources. The derivatives of the objective function with respect to log conductivity are the most cumbersome and need the most CPU-time to be evaluated. For this reason, to compute this derivative only advective transport is considered. The gradient is calculated by the adjoint-state method. The method is demonstrated in a controlled, synthetic study, in which the worth of concentration data is analysed. It is shown that concentration data are essential to improve transport predictions and also help to improve aquifer characterisation and flow predictions, especially in the upstream part of the aquifer, even in the case that a considerable amount of other experimental data like conductivities and heads are available. Besides, conditioning to concentration data reduces the ensemble variances of estimated transmissivity, hydraulic head and concentration. 相似文献