Analysis of radial basis function interpolation approach

The radial basis function （RBF） interpolation approach proposed by Freedman is used to solve inverse problems encountered in well-logging and other petrophysical issues. The approach is to predict petrophysical properties in the laboratory on the basis of physical rock datasets, which include the formation factor, viscosity, permeability, and molecular composition. However, this approach does not consider the effect of spatial distribution of the calibration data on the interpolation result. This study proposes a new RBF interpolation approach based on the Freedman＇s RBF interpolation approach, by which the unit basis functions are uniformly populated in the space domain. The inverse results of the two approaches are comparatively analyzed by using our datasets. We determine that although the interpolation effects of the two approaches are equivalent, the new approach is more flexible and beneficial for reducing the number of basis functions when the database is large, resulting in simplification of the interpolation function expression. However, the predicted results of the central data are not sufficiently satisfied when the data clusters are far apart.     

Bayesian prestack seismic inversion with a self-adaptive Huber-Markov random-field edge protection scheme

Seismic inversion is a highly ill-posed problem, due to many factors such as the limited seismic frequency bandwidth and inappropriate forward modeling. To obtain a unique solution, some smoothing constraints, e.g., the Tikhonov regularization are usually applied. The Tikhonov method can maintain a global smooth solution, but cause a fuzzy structure edge. In this paper we use Huber-Markov random-field edge protection method in the procedure of inverting three parameters, P-velocity, S-velocity and density. The method can avoid blurring the structure edge and resist noise. For the parameter to be inverted, the Huber- Markov random-field constructs a neighborhood system, which further acts as the vertical and lateral constraints. We use a quadratic Huber edge penalty function within the layer to suppress noise and a linear one on the edges to avoid a fuzzy result. The effectiveness of our method is proved by inverting the synthetic data without and with noises. The relationship between the adopted constraints and the inversion results is analyzed as well.     

Accelerating agent-based computation of complex urban systems

Despite its popularity, agent-based modeling is limited by serious barriers that constrain its usefulness as an exploratory tool. In particular, there is a paucity of systematic approaches for extracting coarse-grained, system-level information as it emerges in direct simulation. This is particularly problematic for agent-based models (ABMs) of complex urban systems in which macroscopic phenomena, such as sprawl, may manifest themselves coarsely from bottom-up dynamics among diverse agent-actors interacting across scales. Often these connections are not known, but treating them is nevertheless crucial in enabling prediction, in supporting decisions, and in facilitating the design, control, and optimization of urban systems. In this article, we describe and implement a metasimulation scheme for extracting macroscopic information from local dynamics of agent-based simulation, which allows acceleration of coarse-scale computing and which may also serve as a precursor to handle emergence in complex urban simulation. We compare direct ABM simulation, population-level equation solutions, and coarse projective integration. We apply the scheme to the simulation of urban sprawl from local drivers of urbanization, urban growth, and population dynamics. Numerical examples of the three approaches are provided to compare their accuracy and efficiency. We find that our metasimulation scheme can significantly accelerate complex urban simulations while maintaining faithful representation of the original model.     

简述基于高考评价体系的高考地理主观题阅卷评分细则制定

本文基于评分细则的制定,对《中国高考评价体系》进行解读。高考评价体系坚持立德树人为价值引领、注重学科素养考查、突出创新思维和创新能力评价、以学习探索情境作为考查的载体等。在解读的基础上,提出了评分细则制定的做法并示例,认为要旗帜鲜明地突出“价值引领”原则、突出地理学科素养、重视创新思维和创新能力、关注学习探索情境等。     

Quantifying ice storage in upper Indus river basin using ground-penetrating radar measurements and glacier bed topography model version 2

Ice reserve estimates is a fundamental prerequisite for water resources management. We selected the UIB (upper Indus river basin) as study area because it contains the most abundant mid-latitude glaciers outside the polar region, however, the ice reserve estimates remain unclear due to the harsh topography. In this study, we validated the parameters of the GlabTop2 model (Glacier Bed Topography version 2) using the ice thickness measured by GPR (ground-penetrating radar) and compared the “GPR-measured ice thickness and ice bed elevation” versus “the estimated results obtained from GlabTop2.” Integrated with IDW (inverse distance weighted) interpolated results of glaciers of various sizes, a reasonable parametric scheme (τ = 120 kPa and f = 0.8) of GlabTop2 was applied on vast amounts of glaciers in the UIB region. The GlabTop2 estimates indicated that the ice thickness of the UIB varied from 0 to 736.0 ± 110.0 m, with an average value of 74.5 ± 11.2 m. A significant spatial heterogeneity exists in the sub-basins. The Shyok, Shigar and Hunza that contain the most abundant ice reserve. Lesser quantities are stored in the Western Himalaya and Hindu Kush ranges, which account for 11.3 % and 6.7 % of the total ice reserve in the UIB, respectively. A total volume of 1162.4 ± 175.1 km³ of glacier can be converted to 1046.2 ± 157.6 Gt ice reserve; this is 13.6 times the annual average discharge obtained from the outlet of the Besham hydrological station. We aim to present estimates that can provide the baseline information for glaciology study of the Indus river.     

淮河流域水资源与水环境问题及对策研究

淮河流域是我国重要的粮食产区和工业基地.随着流域内经济社会的快速发展,水资源短缺和污染等问题所造成的影响日益严重.为实现淮河流域水资源的可持续利用,应完善水利工程设施,开发中水和雨水等新的水源;工农业生产采用节水技术;加强水环境保护,防止水质污染;综合规划水资源,构建水资源可持续利用体系.     

北京市社会公众防震减灾科普认知、需求调查研究

为全面系统地评价防震减灾科普效果、准确分析公众的防震减灾科普需求,在2010年上半年开展了面向北京市公众的防震减灾科普现状及需求调查研究.结果表明,58.4%的公众接受过防震减灾科普知识宣传,不同人群接受程度不一;公众对地震预报仍抱有较大的期望,大学生和农民的防震减灾科普知识水平较低;电视、报纸杂志和网络是目前公众获取...     

Numerical simulation of overflow at vertical weirs using a hybrid level set/VOF method

This paper presents the applications of a newly developed free surface flow model to the practical, while challenging overflow problems for weirs. Since the model takes advantage of the strengths of both the level set and volume of fluid methods and solves the Navier-Stokes equations on an unstructured mesh, it is capable of resolving the time evolution of very complex vortical motions, air entrainment and pressure variations due to violent deformations following overflow of the weir crest. In the present study, two different types of vertical weir, namely broad-crested and sharp-crested, are considered for validation purposes. The calculated overflow parameters such as pressure head distributions, velocity distributions, and water surface profiles are compared against experimental data as well as numerical results available in literature. A very good quantitative agreement has been obtained. The numerical model, thus, offers a good alternative to traditional experimental methods in the study of weir problems.     

Numerical analysis of dislocations of the face slabs of the Zipingpu Concrete Faced Rockfill Dam during the Wenchuan earthquake

The Zipingpu Concrete Faced Rockfill Dam (CFRD) was obviously damaged during the Wenchuan earthquake in 2008. A wide range of dislocations occurred along the horizontal construction joints at EL. 845m, between the face slabs constructed in the second and third stages. The maximum displacement of the dislocations reached 17cm. In this study, the slab dislocations were investigated using finite element (FE) analysis. The method based on strain potential was applied to compute the permanent deformation of the Zipingpu Dam during the Wenchuan earthquake. The calculated magnitude of the slab dislocation showed good agreements with the field measurements. The dislocation mechanism was discussed. The results show that the dislocation of the concrete slab is a subsequent damage after the permanent deformation of the rockfill materials. The effects of the shear strength and the direction of the construction joints, the reservoir water level and the seismic waves were studied. The shear strength and the direction of the construction joints, reservoir water level and have a significant effect on the dislocation displacement. The dislocation can be effectively reduced by measures such as changing the direction of the construction joints or improving the shear strength at the horizontal joints.