Research on the Impact of Chinese Digital Inclusive Finance on Industrial Structure Upgrade—Based on Spatial Dubin Model

Based on the panel data of 30 provinces, municipalities, and autonomous regions in China from 2011 to 2018, this paper uses the digital inclusive financial index and industrial structure upgrading coefficient of the Internet Research Center of Peking University as the core explanatory and explained variables to construct a spatial panel. Bin model performs regression analysis on the effect of digital inclusive finance in the upgrading of industrial structure. The results prove that the development of digital inclusive finance in this province and city has significantly promoted the upgrading of the regional industrial structure, and it has a positive overall effect on the upgrading of industrial structure.

Spatial correlation-based characterization of acoustic emission signal-cloud in a granite sample by a cube clustering approach

To extract more in-depth information of acoustic emission(AE)signal-cloud in rock failure under triaxial compression,the spatial correlation of scattering AE events in a granite sample is effectively described by the cube-cluster model.First,the complete connection of the fracture network is regarded as a critical state.Then,according to the Hoshen-Kopelman(HK)algorithm,the real-time estimation of fracture con-nection is effectively made and a dichotomy between cube size and pore fraction is suggested to solve such a challenge of the one-to-one match between complete connection and cluster size.After,the 3D cube clusters are decomposed into orthogonal layer clusters,which are then transformed into the ellip-soid models.Correspondingly,the anisotropy evolution of fracture network could be visualized by three orthogonal ellipsoids and quantitatively described by aspect ratio.Besides,the other three quantities of centroid axis length,porosity,and fracture angle are analyzed to evaluate the evolution of cube cluster.The result shows the sample dilatancy is strongly correlated to four quantities of aspect ratio,centroid axis length,and porosity as well as fracture angle.Besides,the cube cluster model shows a potential pos-sibility to predict the evolution of fracture angle.So,the cube cluster model provides an in-depth view of spatial correlation to describe the AE signal-cloud.

Spatial Patterns and Drivers of Intelligent Manufacturing from a‘Glob-allocal'Perspective:A Study of China's Industrial Robotics

The advancement of the intelligent manufacturing industry(IMI)represents the future direction for the world's manufactur-ing sector,offering a promising avenue to bolster national competitiveness and enhance industrial manufacturing efficiency.In this study,we took the industrial robot industry(IRI)as a case study to elucidate the spatial distribution and interconnections of IMI from a geographical perspective,and the modified diamond model(DM)was used to analyze the influencing factors.Results show that:1)the spatial pattern of IRI with various investment attributes in different industrial chain links is generally similar,centered in the southeast.Key investment areas are in the east and south.The spatial distribution of China's IRI covers a multitude of provinces and obtains differ-ent scales of investment in different countries(regions).2)The spatial correlation between foreign investors and China's provincial-level administrative regions(PARs)forms a network,and the network of foreign-invested enterprises is more stable.Different countries(regions)have distinct location preferences in China,with significant spatial differences in correlation degrees.3)Overall,the interac-tion of these factors shapes the location decisions and correlation patterns of industrial robot enterprises.This study not only contributes to our theoretical knowledge of the industrial spatial structure and industrial economy but also offers valuable references and sugges-tions for national IMI planning and relevant industry investors.

Investigations into the Effect of Spatial Correlation on Channel Estimation and Capacity of Multiple Input Multiple Output System

The paper reports on investigations into the effect of spatial correlation on channel estimation and capacity of a multiple input multiple output (MIMO) wireless communication system. Least square (LS), scaled least square (SLS) and minimum mean square error (MMSE) methods are considered for estimating channel properties of a MIMO system using training sequences. The undertaken mathematical analysis reveals that the accuracy of the scaled least square (SLS) and minimum mean square error (MMSE) channel estimation methods are determined by the sum of eigenvalues of the channel correlation matrix. It is shown that for a fixed transmitted power to noise ratio (TPNR) assumed in the training mode, a higher spatial correlation has a positive effect on the performance of SLS and MMSE estimation methods. The effect of accuracy of the estimated Channel State Information (CSI) on MIMO system capacity is illustrated by computer simulations for an uplink case in which only the mobile station (MS) transmitter is surrounded by scattering objects.

Spatial Correlation Characteristics Analysis of Multi-Beam Channels of Mobile Satellite System

Due to the influence of scatterers around the receiving antenna, the multipath signal in satellite mobile communication systems is correlated with each other which would influence the system performance. There is no systematic standard on the channel modelling of the wideband satellite channel at present, so the study of the modelling of the wideband satellite channel is of great importance. In this paper, firstly we created a multi-beam model which can figure out the antenna gain of the nth component beam. Secondly, we combined the characteristics of multi-beam satellite channel and the distribution of the scatterers, and set up a three-dimension random channel model. This model is more realistic for satellite communication system since it considers the height of scatterers. According to the channel models, we had the formula of spatial correlation coefficient. We used the formula to calculate the relationship between spatial correlation coefficient and the interval of antennas. The result shows that the spatial correlation exists and cannot be ignored while modeling for mobile satellite system.

Cluster modeling of the short-range correlation of acoustically emitted scattering signals

As a widely used measurement technique in rock mechanics,spatial correlation modeling of acoustic emission(AE)scattering signals is attracting increasing focus for describing mechanical behavior quantitatively.Unlike the statistical description of the spatial distribution of randomly generated AE signals,spatial correlation modeling is based mainly on short-range correlation considering the interrelationship of adjacent signals.As a new idea from percolation models,the covering strategy is used to build the most representative cube cluster,which corresponds to the critical scale at peak stress.Its modeling process of critical cube cluster depends strongly on the full connection of the main fracture network,and the corresponding cube for coverage is termed the critical cube.The criticality pertains to not only the transition of local-to-whole connection of the fracture network but also the increasing-to-decreasing transition of the deviatoric stress with an obvious stress drop in the brittle failure of granite.Determining a reasonable critical cube guarantees the best observation scale for investigating the failure process.Besides,the topological connection induces the geometric criticality of three descriptors,namely anisotropy,pore fraction,and specific surface area,which are evaluated separately and effectively.The results show that cluster modeling based on the critical cube is effective and has criticality in both topology and geometry,as well as the triaxial behavior.Furthermore,the critical cube length presents a high confidence probability of being correlated to the mineral particle size.Besides,its pore fraction of cube cluster is influenced strongly by the critical cube length and confining pressure.

Does Foreign Direct Investment Affect S0_(2) Emissions in the Yangtze River Delta?A Spatial Econometric Analysis

As the major source of air pollution,sulfur dioxide(S0_(2))emissions have become the focus of global attention.However,existing studies rarely consider spatial effects when discussing the relationship between foreign direct investment(FDI)and S0_(2) emissions.This study took the Yangtze River Delta as the research area and used the spatial panel data of 26 cities in this region for 2004-2017.The study investigated the spatial agglomeration effects and dynamics at work in FDI and S0_(2) emissions by using global and local measures of spatial autocorrelation.Then,based on regression analysis using a results of traditional ordinary least squares(OLS)model and a spatial econometric model,the spatial Durbin model(SDM)with spatial-time effects was adopted to quantify the impact of FDI on S0_(2) emissions,so as to avoid the regression results bias caused by ignoring the spatial effects.The results revealed a significant spatial autocorrelation between FDI and S0_(2) emissions,both of which displayed obvious path dependence characteristics in their geographical distribution.A series of agglomeration regions were observed on the spatial scale.The estimation results of the SDM showed that FDI inflow promoted S0_(2) emissions,which supports the pollution haven hypothesis.The findings of this study are significant in the prevention and control of air pollution in the Yangtze River Delta.

Spatial spillover effects of official development assistance on environmental pressure in sub-Saharan African(SSA)countries

Impoverished sub-Saharan Africa(SSA)is under increasing environmental pressure from global environmental changes.It is now generally accepted in academic circles that economic development in SSA countries can cause environmental pressure in other countries.However,there is research gap on the impact of economic assistance on environmental pressure in SSA countries and whether economic assistance causes spatial spillovers of environ-mental pressure between SSA countries.To better understand the impact of economic assistance on environmental pressures in SSA,a dynamic spatial Dubin panel model was developed.It helped us explore the spatial spillover effects of economic assistance on environmental pressures in recipient countries based on the panel data from 34 SSA countries.The results show that economic assistance had a positive stimulating effect on environmen-tal pressures of recipient countries,which means that the degree of human disturbance to the environment has deepened.Due to the regional correlation effect,neighboring countries were saddled with environmental pres-sures from the target country.Moreover,environmental pressures have time inertia,which can easily produce a snowball effect.The decomposition of effects shows that the impact of economic assistance on environmental pressures is relatively minor.Environmental pressures have spillover effects,so to deal with diffuse risks,joint regional prevention and control policies should be developed.

肺结核发病的时空分布特征和气象因素分析

通过对2015—2019年全国肺结核发病率数据(不含香港地区、澳门地区和台湾地区)可视化,探究全国肺结核发病的时空分布特征;通过空间自相关分析和拉格朗日乘数(LM)检验,选取面板数据空间杜宾模型探究有关气象因素对肺结核发病的影响。研究结果表明,每年的1月和3月是全国肺结核的高发期,且全国肺结核发病率存在空间聚集性,高发区域是新疆、西藏和青海等西北部地区;气温和湿度与当地肺结核发病是负相关关系,与周边地区的肺结核发病是正相关关系。

On Time-of-Arrival Statistic of Gaussian Channel Model

A model of an angle-spread source, termed the “Gaussian Channel Model” is considered. The cumulative distribution function of the Time-of-Arrival of the multipath components is derived for an arbitrary angle spread. The simple approximate expressions for the Time-of-Arrival cumulative distribution function and probability density function are proposed. Numerical results obtained with the help of the derived expressions show the good coincidence with the experimental data and other known results.

Study on intercarrier interference in mobile MIMO-OFDM based on the geometrical one-ring model

This paper investigates the distribution of intercarrier interference （ICI） in multiple-input multiple-output orthogonal frequency division multiplexing （MIMO-OFDM） systems based on the geometrical one-ring model. Using the spatial and temporal correlation of a geometrical one-ring model, a close-formed expression of intercarrier interference due to the Doppler effect caused by the movement of receiver is derived under the isotropic scattering conditions and non-isotropic scattering conditions. The analytical results are verified by Monte Carlo simulations. We use the generated channels to investigate MIMO-OFDM intercarrier interference under various channel parameters. It can be shown that more than 95% oflCI power comes from five neighboring subcarriers.

绿色技术创新对城市碳减排影响的区域差异和收敛性——来自地级市层面的经验证据

运用我国299个城市的面板数据构建空间杜宾模型,实证研究绿色技术创新对城市碳排放影响的区域差异性和收敛性。结果表明:我国绿色技术创新可以降低碳排放水平,且存在空间关联效应。横向来看,不同区域的绿色技术创新对碳排放的影响具有明显的区域差异性,东部、长三角、珠三角等经济发达地区的影响效应更强,中西部、京津冀等地区相对较弱。纵向来看,2015年以来绿色技术创新对碳排放影响的区域差异持续收敛,根源在于区域经济发展差距的缩小。未来持续推进绿色技术创新、缩小区域发展差距是实现“双碳”目标的必由之路。

区域旅游产业集聚对旅游经济韧性的影响及其空间效应研究——以长江经济带为例

科学洞悉区域旅游集聚对旅游经济韧性的影响及其空间效应,对提升区域旅游经济韧性和实现旅游经济高质量发展意义重大。文章构建区域旅游产业集聚影响旅游经济韧性的机理框架,以长江经济带11省市为案例地,采用区位熵和熵值法得到长江经济带旅游产业集聚度和旅游经济韧性水平,借助面板空间杜宾模型揭示出区域旅游产业集聚对旅游经济韧性的影响及其空间效应。结果表明:(1)研究期内,长江经济带旅游经济韧性水平整体呈上升趋势,且东部地区大于中西部地区,但存在明显的省际差异。长江经济带东部地区旅游经济韧性水平大于中西部,而中西部地区的旅游经济韧性水平增长率大于东部。(2)长江经济带省市旅游产业集聚水平整体上升,受旅游业在当地经济中的地位影响,呈现出西部高于中部,高于东部的格局。(3)区域旅游产业集聚对旅游经济韧性产生明显的正向空间效应,即区域旅游产业集聚不仅可以提升本省旅游经济韧性水平,并且可以产生显著的空间溢出效应来提升省周边区域的旅游经济韧性水平。

云南省毒品犯罪的空间特征与影响因素

研究省域中观尺度的毒品犯罪空间特征和影响因素对打击毒品犯罪、维护社会稳定具有重要意义。文章以云南省129个县区单元的毒品犯罪案件为数据,采用GIS统计分析、空间自相关分析、空间引力模型分析云南省毒品犯罪的空间差异格局和空间关联网络特征。构建由经济水平、收入水平、城镇化程度、受教育水平、流动人口、毒源地影响、地形复杂度组成的毒品犯罪影响因素指标体系,并以空间杜宾模型开展回归分析。结果表明:1)云南省毒品犯罪率呈显著的空间差异格局,高犯罪率集聚区主要分布在中缅边境;2)云南省各区县毒品犯罪在全局层面具有显著的空间关联与空间集聚特征,昆明市主城区—周边各区县以及云南边境各区县间的毒品空间关联网络强度较高;3)毒源地影响因素最为显著,呈显著负相关,距中缅边境(毒源地)距离与毒品犯罪率关系呈拉长的“倒S”型走向分布曲线,表现为大幅度下降、小幅度上升再下降的趋势。此外,经济水平对云南省毒品犯罪差异呈著负向影响,收入水平、城镇化程度为正向影响。

考虑非期望产出的我国物流业效率空间关联网络结构分析

深入研究非期望产出的我国物流业效率的空间关联网络对于推进物流业的低碳转型,促进物流产业区域协同发展具有重要的现实意义。基于2011—2020年我国内陆30个省份的数据,利用超效率SBM模型测算考虑非期望产出的物流业效率,借助修正的引力模型和社会网络分析方法对效率空间关联网络特征及其影响因素进行了分析。结果表明:考虑非期望产出的物流业效率空间关联效应已经突破了地理邻近范围,其空间关联网络结构较为稳定但松散。研究期内,空间关联网络中各地区物流产业辐射关联能力及中介作用表现情况不同。地理位置、经济发展水平差异、科技水平差异和政府支持力度差异对考虑非期望产出的物流业效率空间关联网络结构的形成有显著影响。

考虑空间溢出效应的高速公路交通事故随机参数频次模型

为提高高速公路事故频次模型参数估计的准确性,本文以精细的事故记录、道路属性、交通流状态和天气条件数据为样本,首先,构建传统的事故频次模型并对比拟合效果,选择效果最佳的泊松-对数正态分布模型作为优化的基础模型;之后,为挖掘更多的影响高速公路事故频次的空间效应,在加入条件自回归先验的基础上,本文考虑相邻路段的空间溢出效应,建立一个带有空间溢出协变量的模型分析空间溢出效应对路段事故频次的影响。同时,为描绘数据的异质性对路段事故频次的影响,进一步构建一个随机参数模型。结果表明,空间溢出效应显著有效,考虑空间自相关和空间溢出效应的随机参数模型的拟合优度相较于对照模型明显提升。根据最优模型的参数估计结果进行风险因素甄别,其中,“ln(MADT)”“ln(路段长度)”“1类车”“4类车”“降水”等普通变量以及“1类车S“”圆曲线长S”等空间溢出协变量与事故频次显著相关。

人口老龄化、新质生产力与制造业高质量发展

在人口老龄化的大背景下,发展新质生产力是实现制造业高质量发展的必然选择,加快形成新质生产力是制造业高质量发展的内在要求。为了探究人口老龄化、新质生产力与制造业高质量发展之间的关系,本文利用熵权法分别建立新质生产力和制造业高质量发展的指标体系,通过建立空间杜宾模型对人口老龄化、新质生产力和制造业高质量发展之间的关系进行实证分析。实证结果表明:人口老龄化对制造业高质量发展有显著的负向影响,新质生产力水平对制造业高质量发展有着显著的正向影响;制造业高质量发展水平在逐年提高,东部沿海地区与中西部地区之间的制造业高质量发展水平仍然存在较大差距,呈现出发展不平衡的特征;不同省(区、市)的制造业高质量发展水平具有一定的空间相关性;人口老龄化对东部地区制造业高质量发展的负向影响最为显著,对中、西部地区的负面影响较小,表现出明显的非均衡效应。

基于灰色关联模型的沿黄区域山东段生态安全综合评价及时空演化

以沿黄区域山东段为例,建立PSR模型构建生态安全评价指标体系,借助熵权法和灰色关联度模型对其2000—2018年展开生态安全综合评价,并进行时空演变分析。结果显示,整体上沿黄区域山东段生态安全水平呈现出波动中上升的趋势,由“不安全”向“比较安全”转变,子系统中生态响应和生态状态增加的幅度高于生态环境压力增大的幅度,生态环境有所好转;市级尺度下,山东段17地市生态安全水平有所提高,呈现出“下降-上升-下降”的倒“N”字形演变,生态安全类型以“一般安全”为主,高等级类型较少,城市生态安全问题比较严峻;城市生态安全内部空间差异明显,生态安全空间格局向东、向北转移,呈现出“东高西低”“北高南低”的高低错落分布,高等级生态安全区域从东部沿海向鲁北扩散,“临界安全”区域缩小至鲁中南和鲁西北。最后从生态环境治理与保护、优化调控三大空间、经济结构转型升级等方面提出优化路径,改善生态环境质量。

区域双核结构对城市群科技创新的影响——基于空间杜宾模型的实证分析

城市群的核心优势及功能之一是科技创新,而区域双核结构对城市群的科技创新具有重要影响。基于区域双核结构理论,分别测算了我国19个城市群的中心性和门户性指标并进行聚类分析,发现长三角、京津冀等8个城市群为双核结构,哈长、中原等11个城市群为单核结构。采用空间杜宾模型进一步实证分析发现,区域双核结构显著促进了城市群科技创新水平,并且对南方地区、西部地区以及单一省份组成的城市群的科技创新具有更明显的促进作用。各城市群应注重发挥核心城市对周边科技创新的带动作用促进协调发展;具备双核结构特征的城市群可以充分发挥中心城市数量及空间分布优势,带动城市群发展及科技创新。

数字普惠金融对林业产业发展的影响——基于空间面板模型的实证研究

基于2011—2021年中国31个省份(港澳台地区除外)的面板数据,运用双向固定效应模型以及SDM空间杜宾模型实证分析数字普惠金融对林业产业发展的影响与空间传导机制。研究发现:(1)数字普惠金融对林业产业发展具有显著促进作用,且该结论通过安慰剂检验以及Bartik工具变量等稳健性检验后仍然成立;(2)数字普惠金融对林业产业发展具有异质性,具体表现为区域异质性、生态文明发展程度异质性以及维度异质性;(3)基于空间杜宾模型的实证研究发现数字普惠金融推动林业产业发展具有空间传导效应,本地区数字普惠金融的发展成为拉动周边地区林业产业发展的核心驱动力;(4)由莫兰指数以及莫兰散点图得出林业产业具有“高-高”聚集以及“低-低”聚集的正向空间自相关特征。基于以上研究结论,相关部门应该因地制宜找到适合自己地区发展的数字普惠金融发展战略以推动林业产业的发展。