Exploring the geography of China's airport networks: a hybrid complex-network approach

Air networks are normal examples of transportation systems among ubiquitous big data networks in the dynamic nature. This is particularly the case in developing countries with rapid airport network expansions. This paper explores the structure and evolution of the trunk airport network of China (ANC) in major years during 1980s-2000s. We generalise the complex network approach developed in existing studies and further test for statistical properties of weighted network characteristics by using pair-wise traffic flows. The spatiotemporal decomposition of network metric plots and the visualization maps leads to a rich harvest of stylized ANC structures: (i) national hub-and-spoke patterns surrounding mega-cities; (ii) regional broker patterns surrounding Kunming and Urumqi, and (iii) local heterogeneous disparity patterns in isolated geographical cities, such as Lhasa, Lijiang, Huangshan, etc. These findings have important implications towards understanding the geo-political and economic forces at stake in shaping China's urban systems

The Effect of Training Dataset Size on SAR Automatic Target Recognition Using Deep Learning

Synthetic aperture radar (SAR) is an effective remote sensor for target detection and recognition. Deep learning has a great potential for implementing automatic target recognition based on SAR images. In general, Sufficient labeled data are required to train a deep neural network to avoid overfitting. However, the availability of measured SAR images is usually limited due to high cost and security in practice. In this paper, we will investigate the relationship between the recognition performance and training dataset size. The experiments are performed on three classifiers using MSTAR (Moving and Stationary Target Acquisition and Recognition) dataset. The results show us the minimum size of the training set for a particular classification accuracy

Dynamic And Static Green's Functions In Transversely Isotropic Elastic Media

Concise and numerically feasible dynamic and static Green's functions are obtained in dyadic form by solving the wave equation and the equilibrium equation with general source distribution in transversely isotropic (TI) media. The wave and equilibrium equations are solved by using an extended version of the Kupradze method originally developed for isotropic media. The dynamic Green's function is expressed through three scalar quantities characterizing the propagation of SH and P-SV waves in a transversely isotropic medium. The 2-D inverse Laplacian operator contained in previous Green's function expressions is eliminated without limiting to special cases and geometries. The final dyadic form is similar to that of the isotropic dyadic Green's function, and therefore lends itself to easy analytical and numerical manipulations. The static Green's function has the same dyadic form as the dynamic function except that the three scalars must be redefined. From the dynamic Green's function, displacements due to vertical, horizontal, and explosive sources are explicitly given. The displacements of the explosive source show that an explosive source in a TI medium excites not only the quasi-P wave, but also the quasi-SV wave. The singular properties of the Green's functions are also addressed through their surface integrals in the limit of coinciding receiver and source. The singular contribution is shown to be -1/2 when the static stress Green's function is integrated over a half elliptical surface

Are there interactive effects of physiological and radiative forcing produced by increased CO2 concentration on changes of land hydrological cycle?

AbstractThree coupled climate–carbon cycle models including CESM (Community Earth System Model), CanEsm (the Canadian Centre for Climate Modelling and Analysis Earth System Model) and BCC (Beijing Climate Center Climate System Model) were used to estimate whether changes in land hydrological cycle responded to the interactive effects of CO2-physiological forcing and CO2-radiative forcing. No signs could be indicated that the interactive effects of CO2-physiological forcing and CO2-radiative forcing on the hydrological variables (e.g. precipitation, evapotranspiration and runoff) were detected at global and regional scales. For each model, increases in precipitation, evapotranspiration and runoff (e.g. 0.37, 0.18 and 0.25mm/year2) were simulated in response to CO2-radiative forcing (experiment M3). Decreases in precipitation and evapotranspiration (about −0.02 and −0.09mm/year2) were captured if the CO2 physiological effect was only accounted for (experiment M2). In this experiment, a reverse sign in runoff (the increase of 0.08mm/year2) in contrast to M3 is presented. All models simulated the same signs across Eastern Asia in response to the CO2 physiological forcing and radiative forcing: increases in precipitation and evapotranspiration only considering greenhouse effect; reductions in precipitation and evapotranspiration in response to CO2-physiological effect; and enhanced trends in runoff from all experiments. However, there was still a large uncertainty on the magnitude of the effect of transpiration on runoff (decreased transpiration accounting for 8% to 250% of the increased runoff) from the three models. Two models (CanEsm and BCC) attributed most of the increase in runoff to the decrease in transpiration if the CO2-physiological effect was only accounted for, whereas CESM exhibited that the decrease in transpiration could not totally explain the increase in runoff. The attribution of the CO2-physiological forcing to changes in stomatal conductance versus changes in vegetation structure (e.g. increased Leaf Area Index) is an issue to discuss, and among the three models, no agreement appeared

Borehole Seismic Source Radiation In Layered Isotropic And Anisotropic Media: Boundary Element Modeling

An algorithm based on the boundary element method is established for modeling seismic source radiation from open or cased boreholes in layered transversely isotropic (TI) media. The axis of symmetry of TI layers is assumed to be parallel to the borehole axis. Under this assumption, the problem is significantly simplified because the element discretization of the borehole remains one dimensional. For fluid-filled open boreholes, three equivalent sources on each element are required to represent the boundary effects on the inner fluid and the outer solid. The three boundary conditions for a f1uidsolid interface set up a system of equations for the equivalent sources on all elements. Once the sources are known, displacements in the solid and pressure in the fluid are obtained. For fluid-filled and cased boreholes, the method treats borehole fluid, casing, and cement as a cylindricaliy layered isotropic medium. In this case, the boundary conditions to be satisfied at the borehole wall are four (continuity of the normal and tangential displacements and stresses). The implementation of the method is illustrated through a few examples.United States. Dept. of Energy (Grant DE-FG02-89ERI4084

A School-Library-Centered Community Information Resource Sharing Model and Its Impact on Cultural Life of Rural Communities in China

This paper provides a case study of the rural library programs sponsored by the Evergreen Education Foundation (EEF) and identifies the vital role of school libraries in improving local residents’ access to information and enriching their cultural life. It analyzes the data collected from user surveys of one high school library and one book station from two library clusters in underdeveloped rural Tianzhu and Tongwei counties in Gansu Province of western China to assess the impact and effectiveness of a schoollibrary- centered community information resource sharing model developed and implemented by China Evergreen Rural Library Service Stations (CERLS). A total of 1,350 surveys were distributed to the community library users in the two counties to gain a better understanding of their satisfaction level and expectations of the libraries’ collections, services, and outreach programs, and to examine the impact of the model on the social and economic life of local residents. A quantitative approach was used to analyze the survey data and a standard structure and format of data presentation was followed so that the research might be replicated by CERLS libraries in other locations. As CERLS programs continue to expand into other locations in China, this study may provide useful information and a model to analyze prospective programs. This study could provide impetus for more studies on the rural library programs in other areas of China and in other underdeveloped regions of the world

Growth of Large Domain Epitaxial Graphene on the C-Face of SiC

Growth of epitaxial graphene on the C-face of SiC has been investigated. Using a confinement controlled sublimation (CCS) method, we have achieved well controlled growth and been able to observe propagation of uniform monolayer graphene. Surface patterns uncover two important aspects of the growth, i.e. carbon diffusion and stoichiometric requirement. Moreover, a new "stepdown" growth mode has been discovered. Via this mode, monolayer graphene domains can have an area of hundreds of square micrometers, while, most importantly, step bunching is avoided and the initial uniformly stepped SiC surface is preserved. The stepdown growth provides a possible route towards uniform epitaxial graphene in wafer size without compromising the initial flat surface morphology of SiC.Comment: 18 pages, 8 figure

Making Our Communities Greener: A Case Study of Promoting Biogas Energy by Tongwei Evergreen Libraries in China

Promoting the consumption of new energies, particularly of biogas, in rural areas is a strategic initiative of the Chinese government. The government has incorporated this initiative into many of its rural development plans. Likewise, Tongwei Evergreen Libraries (TEL, 通渭青树图书馆) has also integrated ideas of the initiative into its library services. This paper describes the Biogas Promotion Program (BPP) that TEL implemented, discusses the BPP model and roles of TEL in the program, and analyzes the initial results of the program through surveying local farmers. A survey was developed for this assessment study. The survey results show that the government biogas program has helped save local residents in cutting down fuel costs and improving the efficiency of agricultural processes. The results indicate that more than 50% of biogas users were influenced by the promotional activities held by TEL. The paper recognizes the success of the BPP, explains the limitations of the survey and TEL’s activities, and offers suggestions for future promotional activities