Abstract THE ICT DIFFUSION A SPATIAL ECONOMETRIC APPROACH
光电技术专业英语词汇

《光电技术》专业英语词汇1.Absorption coefficient 吸收系数2.Acceptance angle 接收角3.fibers 光纤4.Acceptors in semiconductors 半导体接收器5.Acousto-optic modulator 声光调制6.Bragg diffraction 布拉格衍射7.Air disk 艾里斑8.angular radius 角半径9.Airy rings 艾里环10.anisotropy 各向异性11.optical 光学的12.refractive index 各向异性13.Antireflection coating 抗反膜14.Argon-ion laser 氩离子激光器15.Attenuation coefficient 衰减系数16.Avalanche 雪崩17.breakdown voltage 击穿电压18.multiplication factor 倍增因子19.noise 燥声20.Avalanche photodiode(APD) 雪崩二极管21.absorption region in APD APD 吸收区域22.characteristics-table 特性表格23.guard ring 保护环24.internal gain 内增益25.noise 噪声26.photogeneration 光子再生27.primary photocurrent 起始光电流28.principle 原理29.responsivity of InGaAs InGaAs 响应度30.separate absorption and multiplication(SAM) 分离吸收和倍增31.separate absorption grading and multiplication(SAGM) 分离吸收等级和倍增32.silicon 硅33.Average irradiance 平均照度34.Bandgap 带隙35.energy gap 能级带隙36.bandgap diagram 带隙图37.Bandwidth 带宽38.Beam 光束39.Beam splitter cube 立方分束器40.Biaxial crystal双s 轴晶体41.Birefringent 双折射42.Bit rate 位率43.Black body radiation law 黑体辐射法则44.Bloch wave in a crystal 晶体中布洛赫波45.Boundary conditions 边界条件46.Bragg angle 布拉格角度47.Bragg diffraction condition 布拉格衍射条件48.Bragg wavelength 布拉格波长49.Brewster angle 布鲁斯特角50.Brewster window 布鲁斯特窗51.Calcite 霰石52.Carrier confinement 载流子限制53.Centrosymmetric crystals 中心对称晶体54.Chirping 啁啾55.Cladding 覆层56.Coefficient of index grating 指数光栅系数57.Coherence连贯性pensation doping 掺杂补偿59.Conduction band 导带60.Conductivity 导电性61.Confining layers 限制层62.Conjugate image 共轭像63.Cut-off wavelength 截止波长64.Degenerate semiconductor 简并半导体65.Density of states 态密度66.Depletion layer 耗尽层67.Detectivity 探测率68.Dielectric mirrors 介电质镜像69.Diffraction 衍射70.Diffraction g rating 衍射光栅71.Diffraction grating equation 衍射光栅等式72.Diffusion current 扩散电流73.Diffusion flux 扩散流量74.Diffusion Length 扩散长度75.Diode equation 二极管公式76.Diode ideality factor 二极管理想因子77.Direct recombinatio直n接复合78.Dispersion散射79.Dispersive medium 散射介质80.Distributed Bragg reflector 分布布拉格反射器81.Donors in semiconductors 施主离子82.Doppler broadened linewidth 多普勒扩展线宽83.Doppler effect 多普勒效应84.Doppler shift 多普勒位移85.Doppler-heterostructure 多普勒同质结构86.Drift mobility 漂移迁移率87.Drift Velocity 漂移速度88.Effective d ensity o f s tates 有效态密度89.Effective mass 有效质量90.Efficiency 效率91.Einstein coefficients 爱因斯坦系数92.Electrical bandwidth of fibers 光纤电子带宽93.Electromagnetic wave 电磁波94.Electron affinity 电子亲和势95.Electron potential energy in a crystal 晶体电子阱能量96.Electro-optic effects 光电子效应97.Energy band 能量带宽98.Energy band diagram 能量带宽图99.Energy level 能级100.E pitaxial growth 外延生长101.E rbium doped fiber amplifier 掺饵光纤放大器102.Excess carrier distribution 过剩载流子扩散103.External photocurrent 外部光电流104.Extrinsic semiconductors 本征半导体105.Fabry-Perot laser amplifier 法布里-珀罗激光放大器106.Fabry-Perot optical resonator 法布里-珀罗光谐振器107.Faraday effect 法拉第效应108.Fermi-Dirac function 费米狄拉克结109.Fermi energy 费米能级110.Fill factor 填充因子111.Free spectral range 自由谱范围112.Fresnel’s equations 菲涅耳方程113.Fresnel’s optical indicatrix 菲涅耳椭圆球114.Full width at half maximum 半峰宽115.Full width at half power 半功率带宽116.Gaussian beam 高斯光束117.Gaussian dispersion 高斯散射118.Gaussian pulse 高斯脉冲119.Glass perform 玻璃预制棒120.Goos Haenchen phase shift Goos Haenchen 相位移121.Graded index rod lens 梯度折射率棒透镜122.Group delay 群延迟123.Group velocity 群参数124.Half-wave plate retarder 半波延迟器125.Helium-Neon laser 氦氖激光器126.Heterojunction 异质结127.Heterostructure 异质结构128.Hole 空穴129.Hologram 全息图130.Holography 全息照相131.Homojunction 同质结132.Huygens-Fresnel principle 惠更斯-菲涅耳原理133.Impact-ionization 碰撞电离134.Index matching 指数匹配135.Injection 注射136.Instantaneous irradiance 自发辐射137.Integrated optics 集成光路138.Intensity of light 光强139.Intersymbol interference 符号间干扰140.Intrinsic concentration 本征浓度141.Intrinsic semiconductors 本征半导体142.Irradiance 辐射SER 激光144.active medium 活动介质145.active region 活动区域146.amplifiers 放大器147.cleaved-coupled-cavity 解理耦合腔148.distributed Bragg reflection 分布布拉格反射149.distributed feedback 分布反馈150.efficiency of the He-Ne 氦氖效率151.multiple quantum well 多量子阱152.oscillation condition 振荡条件ser diode 激光二极管sing emission 激光发射155.LED 发光二极管156.Lineshape function 线形结157.Linewidth 线宽158.Lithium niobate 铌酸锂159.Load line 负载线160.Loss c oefficient 损耗系数161.Mazh-Zehnder modulator Mazh-Zehnder 型调制器162.Macrobending loss 宏弯损耗163.Magneto-optic effects 磁光效应164.Magneto-optic isolator 磁光隔离165.Magneto-optic modulator 磁光调制166.Majority carriers 多数载流子167.Matrix emitter 矩阵发射168.Maximum acceptance angle 最优接收角169.Maxwell’s wave equation 麦克斯维方程170.Microbending loss 微弯损耗171.Microlaser 微型激光172.Minority carriers 少数载流子173.Modulated directional coupler 调制定向偶合器174.Modulation of light 光调制175.Monochromatic wave 单色光176.Multiplication region 倍增区177.Negative absolute temperature 负温度系数 round-trip optical gain 环路净光增益179.Noise 噪声180.Noncentrosymmetric crystals 非中心对称晶体181.Nondegenerate semiconductors 非简并半异体182.Non-linear optic 非线性光学183.Non-thermal equilibrium 非热平衡184.Normalized frequency 归一化频率185.Normalized index difference 归一化指数差异186.Normalized propagation constant 归一化传播常数187.Normalized thickness 归一化厚度188.Numerical aperture 孔径189.Optic axis 光轴190.Optical activity 光活性191.Optical anisotropy 光各向异性192.Optical bandwidth 光带宽193.Optical cavity 光腔194.Optical divergence 光发散195.Optic fibers 光纤196.Optical fiber amplifier 光纤放大器197.Optical field 光场198.Optical gain 光增益199.Optical indicatrix 光随圆球200.Optical isolater 光隔离器201.Optical Laser amplifiers 激光放大器202.Optical modulators 光调制器203.Optical pumping 光泵浦204.Opticalresonator 光谐振器205.Optical tunneling光学通道206.Optical isotropic 光学各向同性的207.Outside vapor deposition 管外气相淀积208.Penetration depth 渗透深度209.Phase change 相位改变210.Phase condition in lasers 激光相条件211.Phase matching 相位匹配212.Phase matching angle 相位匹配角213.Phase mismatch 相位失配214.Phase modulation 相位调制215.Phase modulator 相位调制器216.Phase of a wave 波相217.Phase velocity 相速218.Phonon 光子219.Photoconductive detector 光导探测器220.Photoconductive gain 光导增益221.Photoconductivity 光导性222.Photocurrent 光电流223.Photodetector 光探测器224.Photodiode 光电二极管225.Photoelastic effect 光弹效应226.Photogeneration 光子再生227.Photon amplification 光子放大228.Photon confinement 光子限制229.Photortansistor 光电三极管230.Photovoltaic devices 光伏器件231.Piezoelectric effect 压电效应232.Planck’s radiation distribution law 普朗克辐射法则233.Pockels cell modulator 普克尔斯调制器234.Pockel coefficients 普克尔斯系数235.Pockels phase modulator 普克尔斯相位调制器236.Polarization 极化237.Polarization transmission matrix 极化传输矩阵238.Population inversion 粒子数反转239.Poynting vector 能流密度向量240.Preform 预制棒241.Propagation constant 传播常数242.Pumping 泵浦243.Pyroelectric detectors 热释电探测器244.Quantum e fficiency 量子效应245.Quantum noise 量子噪声246.Quantum well 量子阱247.Quarter-wave plate retarder 四分之一波长延迟248.Radiant sensitivity 辐射敏感性249.Ramo’s theorem 拉莫定理250.Rate equations 速率方程251.Rayleigh criterion 瑞利条件252.Rayleigh scattering limit 瑞利散射极限253.Real image 实像254.Recombination 复合255.Recombination lifetime 复合寿命256.Reflectance 反射257.Reflection 反射258.Refracted light 折射光259.Refractive index 折射系数260.Resolving power 分辩力261.Response time 响应时间262.Return-to-zero data rate 归零码263.Rise time 上升时间264.Saturation drift velocity 饱和漂移速度265.Scattering 散射266.Second harmonic generation 二阶谐波267.Self-phase modulation 自相位调制268.Sellmeier dispersion equation 色列米尔波散方程式269.Shockley equation 肖克利公式270.Shot noise 肖特基噪声271.Signal to noise ratio 信噪比272.Single frequency lasers 单波长噪声273.Single quantum well 单量子阱274.Snell’s law 斯涅尔定律275.Solar cell 光电池276.Solid state photomultiplier 固态光复用器277.Spectral intensity 谱强度278.Spectral responsivity 光谱响应279.Spontaneous emission 自发辐射280.stimulated emission 受激辐射281.Terrestrial light 陆地光282.Theraml equilibrium 热平衡283.Thermal generation 热再生284.Thermal velocity 热速度285.Thershold concentration 光强阈值286.Threshold current 阈值电流287.Threshold wavelength 阈值波长288.Total acceptance angle 全接受角289.Totla internal reflection 全反射290.Transfer distance 转移距离291.Transit time 渡越时间292.Transmission coefficient 传输系数293.Tramsmittance 传输294.Transverse electric field 电横波场295.Tranverse magnetic field 磁横波场296.Traveling vave lase 行波激光器297.Uniaxial crystals 单轴晶体298.UnPolarized light 非极化光299.Wave 波300.W ave equation 波公式301.Wavefront 波前302.Waveguide 波导303.Wave n umber 波数304.Wave p acket 波包络305.Wavevector 波矢量306.Dark current 暗电流307.Saturation signal 饱和信号量308.Fringing field drift 边缘电场漂移plementary color 补色310.Image lag 残像311.Charge handling capability 操作电荷量312.Luminous quantity 测光量313.Pixel signal interpolating 插值处理314.Field integration 场读出方式315.Vertical CCD 垂直CCD316.Vertical overflow drain 垂直溢出漏极317.Conduction band 导带318.Charge coupled device 电荷耦合组件319.Electronic shutter 电子快门320.Dynamic range 动态范围321.Temporal resolution 动态分辨率322.Majority carrier 多数载流子323.Amorphous silicon photoconversion layer 非晶硅存储型324.Floating diffusion amplifier 浮置扩散放大器325.Floating gate amplifier 浮置栅极放大器326.Radiant quantity 辐射剂量327.Blooming 高光溢出328.High frame rate readout mode 高速读出模式329.Interlace scan 隔行扫描330.Fixed pattern noise 固定图形噪声331.Photodiode 光电二极管332.Iconoscope 光电摄像管333.Photolelctric effect 光电效应334.Spectral response 光谱响应335.Interline transfer CCD 行间转移型CCD336.Depletion layer 耗尽层plementary metal oxide semi-conductor 互补金属氧化物半导体338.Fundamental absorption edge 基本吸收带339.Valence band 价带340.Transistor 晶体管341.Visible light 可见光342.Spatial filter 空间滤波器343.Block access 块存取344.Pupil compensation 快门校正345.Diffusion current 扩散电流346.Discrete cosine transform 离散余弦变换347.Luminance signal 高度信号348.Quantum efficiency 量子效率349.Smear 漏光350.Edge enhancement 轮廓校正351.Nyquist frequency 奈奎斯特频率352.Energy band 能带353.Bias 偏压354.Drift current 漂移电流355.Clamp 钳位356.Global exposure 全面曝光357.Progressive scan 全像素读出方式358.Full frame CCD 全帧CCD359.Defect correction 缺陷补偿360.Thermal noise 热噪声361.Weak inversion 弱反转362.Shot noise 散粒噪声363.Chrominance difference signal 色差信号364.Colotremperature 色温365.Minority carrier 少数载流子366.Image stabilizer 手振校正367.Horizontal CCD 水平CCD368.Random noise 随机噪声369.Tunneling effect 隧道效应370.Image sensor 图像传感器371.Aliasing 伪信号372.Passive 无源373.Passive pixel sensor 无源像素传感器374.Line transfer 线转移375.Correlated double sampling 相关双采样376.Pinned photodiode 掩埋型光电二极管377.Overflow 溢出378.Effective pixel 有效像素379.Active pixel sensor 有源像素传感器380.Threshold voltage 阈值电压381.Source follower 源极跟随器382.Illuminance 照度383.Refraction index 折射率384.Frame integration 帧读出方式385.Frame interline t ransfer CCD 帧行间转移CCD 386.Frame transfer 帧转移387.Frame transfer CCD 帧转移CCD388.Non interlace 逐行扫描389.Conversion efficiency 转换效率390.Automatic gain control 自动增益控制391.Self-induced drift 自激漂移392.Minimum illumination 最低照度393.CMOS image sensor COMS 图像传感器394.MOS diode MOS 二极管395.MOS image sensor MOS 型图像传感器396.ISO sensitivity ISO 感光度。
石家庄市城区公共文化设施分布特征与可达性研究

1152023.07 / Urban and Rural Planning and Design 城乡规划·设计公共文化设施是城市文化的物质基础和重要载体,是开展文化创意活动的基础服务设施,是更好地为城市居民提供各类创新文化服务,包括图书馆、文化馆、博物馆、美术馆、科技馆及各类活动中心等的设施[1]。
《河北省公共文化服务体系建设“十四五”规划》指出,要保障居民获取文化权益的基本途径,推进覆盖全社会公共文化体系一体化建设,从而实现基本公共文化服务高质量发展。
而近年来,河北省地区公共文化设施存在布局不均衡、资源配置浪费与缺位等不同程度的问题,未形成一定的规模效益和整体优势[2]。
其中,作为新城区扩建的石家庄市区,统筹协调发展新旧城区间公共文化设施均等化建设,便成为当下提升石家庄城市形象和文化竞争力刻不容缓的研究主题。
基于大数据时代的背景下,将POI 大数据与ArcGIS 分析方法应用于文化设施研究,进行公共服务设施可达性理论的实践,以期为石家庄市城区相关研究和实践提供理论与技术借鉴。
研究将以公益性为主,且为市区级及以上的大中型公共文化设施作为研究对象,其中也包括国家级文保单位,以及省级、区域级设施,在本工作统计中统一称为市区级大中型公共文化设施,简称公共文化设施[3]。
本工作将公共文化设施分为三种分类项目,有别于体育及文娱类设施(见表1),属于用地分类中部分A 类和B 类设施。
R 类用地中文化站类服务设施属于基层单位,本次不作探讨[4]。
摘要 文化竞争力逐渐成为城市内生发展的动力源泉,而公共文化设施作为城市文化的物质载体,日益成为关注焦点。
基于石家庄多源数据,利用标准差椭圆分析法、改进的高斯两步移动搜寻法等GIS 模型,对石家庄市城区公共文化设施的分布特征及可达性进行分析。
结果表明:①文化设施与居民点在空间扩散方向存在“错位”,文化设施在外围城区配置不均衡;②文化设施可达性在不同搜寻半径下分布规律不同,搜寻时间越长可达性圈层特征越明显,可达性水平呈现均衡态势;③文化设施综合可达性呈现多中心圈层分布,而外围四区街道乡镇文化设施可达性总体较差。
图神经网络综述

第47卷第4期Vol.47No.4计算机工程Computer Engineering2021年4月April 2021图神经网络综述王健宗,孔令炜,黄章成,肖京(平安科技(深圳)有限公司联邦学习技术部,广东深圳518063)摘要:随着互联网和计算机信息技术的不断发展,图神经网络已成为人工智能和大数据处理领域的重要研究方向。
图神经网络可对相邻节点间的信息进行有效传播和聚合,并将深度学习理念应用于非欧几里德空间的数据处理中。
简述图计算、图数据库、知识图谱、图神经网络等图结构的相关研究进展,从频域和空间域角度分析与比较基于不同信息聚合方式的图神经网络结构,重点讨论图神经网络与深度学习技术相结合的研究领域,总结归纳图神经网络在动作检测、图系统、文本和图像处理任务中的具体应用,并对图神经网络未来的发展方向进行展望。
关键词:图神经网络;图结构;图计算;深度学习;频域;空间域开放科学(资源服务)标志码(OSID ):中文引用格式:王健宗,孔令炜,黄章成,等.图神经网络综述[J ].计算机工程,2021,47(4):1-12.英文引用格式:WANG Jianzong ,KONG Lingwei ,HUANG Zhangcheng ,et al.Survey of graph neural network [J ].Computer Engineering ,2021,47(4):1-12.Survey of Graph Neural NetworkWANG Jianzong ,KONG Lingwei ,HUANG Zhangcheng ,XIAO Jing(Federated Learning Technology Department ,Ping An Technology (Shenzhen )Co.,Ltd.,Shenzhen ,Guangdong 518063,China )【Abstract 】With the continuous development of the computer and Internet technologies ,graph neural network has become an important research area in artificial intelligence and big data.Graph neural network can effectively transmit and aggregate information between neighboring nodes ,and applies the concept of deep learning to the data processing of non-Euclidean space.This paper briefly introduces the research progress of graph computing ,graph database ,knowledge graph ,graph neural network and other graph-based techniques.It also analyses and compares graph neural network structures based on different information aggregation modes in the spectral and spatial domain.Then the paper discusses research fields that combine graph neural network with deep learning ,and summarizes the specific applications of graph neural networks in action detection ,graph systems ,text and image processing tasks.Finally ,it prospects the future development research directions of graph neural networks.【Key words 】graph neural network ;graph structure ;graph computing ;deep learning ;spectral domain ;spatial domain DOI :10.19678/j.issn.1000-3428.00583820概述近年来,深度学习技术逐渐成为人工智能领域的研究热点和主流发展方向,主要应用于高维特征规则分布的非欧几里德数据处理中,并且在图像处理、语音识别和语义理解[1]等领域取得了显著成果。
stablediffusion 描述词

stablediffusion 描述词Stable Diffusion: Exploring the Dynamics of a Fundamental ProcessIntroductionStable diffusion is a fundamental process that plays a crucial role in various fields, including physics, chemistry, biology, and economics. It refers to the random movement of particles or molecules from an area of high concentration to an area of low concentration, eventually leading to equilibrium. This article aims to delve into the concept of stable diffusion, its underlying principles, and its applications in different domains.Understanding Stable DiffusionStable diffusion follows Fick's laws, which describe the behavior of diffusing particles. Fick's first law states that the rate of diffusion is directly proportional to the concentration gradient. In other words, the greater the difference in concentration, the faster the diffusion. This law can be mathematically represented as J = -D(dC/dx), where J is the diffusion flux, D is the diffusion coefficient, C is theconcentration, and x is the spatial coordinate.Fick's second law extends the understanding of diffusion by considering how the concentration changes over time. It states that the rate of change of concentration with respect to time is proportional to the rate of change of the concentration gradient. Mathematically, this law can be expressed as ∂C/∂t = D(∂^2C/∂x^2), where ∂C/∂t is the rate of change of concentration, and ∂^2C/∂x^2 is the rate of change of the concentration gradient.Applications of Stable Diffusion1. Physics: Stable diffusion is widely observed in physics, particularly in the study of Brownian motion. Brownian motion refers to the random movement of particles in a fluid due to the collision with other particles. It has significant implications in various areas of physics, such as statistical mechanics and thermodynamics.2. Chemistry: Stable diffusion is fundamental to chemical reactions. It enables the mixing of different substances, allowing reactions to occur. For example, during the process of osmosis, solvent molecules move across a semi-permeablemembrane from an area of low solute concentration to an area of high solute concentration until equilibrium is reached.3. Biology: Stable diffusion plays a crucial role in biological systems. One notable example is the diffusion of oxygen and carbon dioxide in the respiratory system. Oxygen molecules diffuse from the alveoli in the lungs to the bloodstream, where they are transported to tissues. Conversely, carbon dioxide diffuses from the tissues to the bloodstream and is eliminated through exhalation.4. Economics: Stable diffusion is also relevant in the field of economics. It is used to analyze the spread of ideas, innovations, and information through social networks. Diffusion models, such as the Bass model, help economists understand the adoption and diffusion of new products or technologies in a population.Stable Diffusion in Real-Life Situations1. Environmental Pollution: Stable diffusion plays a significant role in understanding the dispersion of pollutants in the environment. By analyzing diffusion patterns, researchers can assess the impact of pollutants on ecosystems and humanhealth. This knowledge aids in developing effective mitigation strategies and policies.2. Drug Delivery: The study of stable diffusion is essential in drug delivery systems. Understanding how drugs diffuse within the body allows for designing optimal drug formulations and delivery methods. This knowledge contributes to enhancing drug efficacy and minimizing potential side effects.3. Financial Markets: Stable diffusion models are utilized to analyze the diffusion of stock prices and market trends. By studying diffusion patterns, investors can make informed decisions regarding investments and assess the risk associated with specific assets.ConclusionStable diffusion is a fundamental process that governs the random movement of particles or molecules in various fields. By understanding the principles of stable diffusion, scientists and researchers can gain insights into the behavior of different systems. From physics to economics, stable diffusion plays a vital role in explaining and predicting a wide range ofphenomena. Its applications are diverse and have significant implications for advancing our understanding of the world around us.。
山东省新型冠状病毒肺炎疫情空间分异

Geographical Science Research 地理科学研究, 2021, 10(2), 137-143Published Online May 2021 in Hans. /journal/gserhttps:///10.12677/gser.2021.102017山东省新型冠状病毒肺炎疫情空间分异戴怡昕,秦鹏*青岛农业大学资源与环境学院,山东青岛收稿日期:2021年4月16日;录用日期:2021年5月17日;发布日期:2021年5月24日摘要新型冠状病毒肺炎目前仍呈现全球大流行趋势,在中国疫情基本结束的情况下,科学探究疫情空间分异特征,对当前国际第二波疫情具有指导意义。
基于截至2020年4月16日24时山东省各县(市、区)病例数据,在区县尺度上对病例数进行空间自相关分析。
结果显示:山东省疫情经历了爆发、有效控制和稳定的发展过程,累计报告确诊病例763例,病例遍布山东省137个县(市、区)中的99个,覆盖比例达72.26%,各县域疫情空间分布差异明显;山东省疫情呈现空间极化特性,部分区县呈现空间扩散特点,热点区域主要集中于济宁市。
由此可知,新型冠状病毒肺炎在山东省存在明显空间分异性,预防和控制传播的措施也应因地制宜。
关键词空间自相关,地理探测,新型冠状病毒肺炎,山东省Spatial Distribution of COVID-19 inShandong Province, ChinaYixin Dai, Peng Qin*School of Resources and Environment, Qingdao Agricultural University, Qingdao ShandongReceived: Apr. 16th, 2021; accepted: May 17th, 2021; published: May 24th, 2021AbstractCOVID-19 is still showing the trend of global pandemic. With the end of the epidemic situation in China, it is instructive for current international second wave of epidemic to scientifically explore *通讯作者。
河南省新型城镇化发展质量评价实证研究

河南科技Henan Science and Technology科技管理总第817期第23期2023年12月收稿日期:2023-08-13基金项目:河南省软科学课题(202400410204)。
作者简介:张举(1989—),女,硕士,工程师,研究方向:新型城镇化、国土空间规划相关方向;吴晓宁(1986—),男,硕士,工程师,研究方向:新型城镇化、城乡规划与设计;郭萌萌(1990—),女,硕士,经济师,研究方向:区域经济、社会经济学;张中(1991—),男,硕士,经济师,研究方向:区域经济学、产业经济等。
河南省新型城镇化发展质量评价实证研究张举1吴晓宁2郭萌萌3张中1(1.河南省项目推进中心,河南郑州450000;2.郑州大学建设科技集团,河南郑州450000;3.郑州大学第五附属医院,河南郑州450000)摘要:【目的】河南省新型城镇化发展已经进入了质量与速度并重的转型发展新阶段,需对“十四五”时期河南省新型城镇化如何实现高质量发展进行研究。
【方法】本研究初步建立了新型城镇化质量评价体系,并运用熵值法对河南省18个地市的城镇化发展质量进行评价。
【结果】评价结果显示,河南省新型城镇化人口指数普遍不高,城镇化率偏低;经济发展程度差距较大,省会城市优势突出;生态环境水平整体较低,环境提升任务重;国土空间利用效能较低,资源利用不集约;城乡融合程度较低,呈现两个极端;重点领域基本公共服务配套缺失明显等。
【结论】河南省城镇化质量呈现整体水平不高、空间分布以郑州为中心的圈层递减、区域经济发展由极化阶段向扩散阶段转变、“生态环境指数”与“空间效能指数”相互拮抗等特征。
提出了县域人口就地城镇化、提高科技创新能力、打造区域一体化基础设施体系、完善基本公共服务设施均等化配置、提高生态环境水平等措施,为河南省城镇化高质量发展提供参考。
关键词:河南省;新型城镇化;质量评价;建议措施中图分类号:F291.1文献标志码:A 文章编号:1003-5168(2023)23-0145-06DOI :10.19968/ki.hnkj.1003-5168.2023.23.030An Empirical Study on Quality Evaluation of New UrbanizationDevelopment in Henan ProvinceZHANG Ju 1WU Xiaoning 2GUO Mengmeng 3ZHANG Zhong 1(1.Project promotion Center of Henan Province,Zhengzhou 450000,China;2.Construction and Technology Group Co.,Ltd.,of Zhengzhou University,Zhengzhou 450000,China;3.The Fifth Affiliated Hospital ofZhengzhou University,Zhengzhou 450000,China )Abstract:[Purposes ]As the development of new urbanization in Henan Province has entered a newstage of transformation and development with equal quality and speed,it is necessary to study how to re⁃alize the high-quality development of the new urbanization of Henan Province during the "Fourteenth Five -Year Plan"period.[Methods ]By establishing an evaluation system of urbanization quality,and us⁃ing the entropy method the urbanization development quality of 18cities in Henan Province is evaluated.[Findings ]The evaluation results show that urbanization in Henan province has the following character⁃istics:the population index is generally low and the urbanization rate is low;There is a big gap in the de⁃gree of economic development,and the advantages of provincial capitals are outstanding;The overall level of ecological environment is low,and the task of environmental improvement is heavy;The effi⁃ciency of land space utilzation is low and the lization of resources is not intensive;The degree of urban-rural integration is low,showing two extremes;The lack of basic public service facilities in key areas is obvious.[Conclusions]The following conclusions were drawn:the overall level of urbanization quality in Henan Province is not high,the spatial distribution is centered on Zhengzhou,showing a decreasing trend,and the regional economic development is changing from polarization stage to diffusion stage,and the"ecological environment index"and"spatial efficiency index"are mutually constrained.Finally,this paper puts forward the following measures,which can provide reference for the development of Henan: urbanization of county population,improvement of scientific and technological innovation ability,cre⁃ation of regional integrated infrastructure system,improvement of equal allocation of basic public service facilities,and improvement of ecological environment level.Keywords:Henan Province;new urbanization;quality evaluation;proposal0引言2019年,我国常住人口城镇化率首次超过60%,达到60.06%,这意味着我国即将进入城市化进程中后期,即各种社会矛盾和问题集中突显时期。
基于多特征自适应融合的区块链异常交易检测方法
2021年5月Journal on Communications May 2021 第42卷第5期通信学报V ol.42No.5基于多特征自适应融合的区块链异常交易检测方法朱会娟1,2,陈锦富1,2,李致远1,2,殷尚男1,2(1. 江苏大学计算机科学与通信工程学院,江苏镇江 212013;2. 江苏省工业网络安全技术重点实验室,江苏镇江 212013)摘 要:针对智能检测模型的性能受限于原始数据(特征)表达能力的问题,设计了一种残差网络结构ResNet-32用于挖掘区块链交易特征间隐含的关联关系,自动学习包含丰富语义信息的高层抽象特征。
虽然浅层特征区分能力弱,但更忠于原始交易细节的描述,如何充分利用两者的优势是提升异常交易检测性能的关键,因此提出了特征融合方法自适应地桥接高层抽象特征与原始特征之间的鸿沟,自动去除其噪声和冗余信息,并挖掘两者的交叉特征信息获得最具区分力的特征。
最后,结合以上方法提出区块链异常交易检测模型(BATDet),并通过Elliptic数据集验证了所提模型在区块链异常交易检测领域的有效性。
关键词:区块链;残差网络;异常检测;Logistic回归中图分类号:TP18文献标识码:ADOI: 10.11959/j.issn.1000−436x.2021030Block-chain abnormal transaction detection methodbased on adaptive multi-feature fusionZHU Huijuan1,2, CHEN Jinfu1,2, LI Zhiyuan1,2, YIN Shangnan1,21. School of Computer Science and Communication Engineering, Jiangsu University, Zhenjiang 212013, China2. Jiangsu Key Laboratory of Security Technology for Industrial Cyberspace, Zhenjiang 212013, ChinaAbstract: Aiming at the problem that the performance of intelligent detection models was limited by the representation ability of original data (features), a residual network structure ResNet-32 was designed to automatically mine the intricate association relationship between original features, so as to actively learn the high-level abstract features with rich seman-tic information. Low-level features were more transaction content descriptive, although their distinguishing ability was weaker than that of the high-level features. How to integrate them together to obtain complementary advantages was the key to improve the detection performance. Therefore, multi feature fusion methods were proposed to bridge the gap be-tween the two kinds of features. Moreover, these fusion methods can automatically remove the noise and redundant in-formation from the integrated features and further absorb the cross information, to acquire the most distinctive features.Finally, block-chain abnormal transaction detection model (BATDet) was proposed based on the above presented me-thods, and its effectiveness in the abnormal transaction detection is verified.Keywords: block-chain, residual network, abnormal detection, Logistic regression1引言科技的飞速发展促使金融行业从实体金融走向互联网金融,反洗钱的外部环境和内在逻辑均发生了深刻而复杂的变化。
皮肤的屏障作用英文文献
Moisturization and skin barrier functionABSTRACT: Over the past decade,great progress has been made toward elucidating the structure and function of the stratum corneum (SC),the outermost layer of the epidermis. SC cells (corneocytes) protect against desiccation and environmental by the SC is largely dependent on several factors. First, intercellular lamellar lipids, organized predominantly in an orthorhombic gel phase, provide an effective barrier to the passage of water through the tissue. Secondly, the diffusion path length also retards water loss, since water must traverse the tortuous path created by the SC layers and corneocyte envelopes. Thirdly, and equally important, is natural moisturizing factor (NMF), a complex mixture of low-molecular-weight, water-soluble compounds first formed within thee corneocytes by degradation of the histidine-rich protein known as filaggrin. Each maturation step leading to the formation of an effective moisture barrier-including corneocyte strengthening, lipid processing, and NMF generation-is influenced by the level of SC hydration. These processes, as well as the final step of corneodesmolysis that mediates exfoliations, are often disturbed upon environmental challenge, resulting in dry, flaky skin conditions. The present paper reviews our current understanding of the biology of the SC, particularly its homeostatic mechanisms of hydration.Keywords: corneocyte, corneodesmolysis, filaggrin, natural moisturizing factor, stratum corneum.IntroductionFor humans to survive in a terrestrial environment, the loss of water from the skin must be carefully regulated by the epidermis, a function dependent on the complex nature of its outer layer, the stratum corneum (SC) (1)。
面向目标检测的稀疏表示方法研究进展_高仕博
1
引言
随着成像传感器技术的发展, 人类扩展了获取图像 信息的广度和深度, 加深了人类对客观世界的认识, 能 观察到人眼能感知到和感知不到的物体, 根据所用传感 器的不同, 常见的图像有彩色图像 、 红外图像 、 高光谱图 像、 合成孔径雷达图像及核磁共振图像等 . 对于获取的 大量图像信息, 人们期望借助计算机实现智能化处理, 达到对场景的自动分析和理解 . 目标检测的任务是从获 取的图像中分割出感兴趣的区域, 作为图像理解的一个
第2 期 2015 年 2 月
电 子 学 报 ACTA ELECTRONICA SINICA
Vol. 43 No. 2 Feb. 2015
面向目标检测的稀疏表示方法研究进展
1 2 1, 3 1, 3 高仕博 , 程咏梅 , 肖利平 , 韦海萍
( 1. 北京航天自动控制研究所, 北京 100854 ; 2. 西北工业大学自动化学院, 陕西西安 710072 ; 3. 宇航智能控制技术国家级重点实验室, 北京 100854 )
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( 5)
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技术创新扩散的影响因素综述
收稿日期:2012-01-27㊀㊀㊀㊀修回日期:2012-03-03基金项目:国家软科学计划项目 基于TRIZ 理论的高新技术企业创新模式与管理方法研究 (编号:2010GXS 5D 198);教育部人文社会科学(青年)项目 基于产业联盟的产业技术标准化路径与运作模式研究 (编号:10YJC 630246);黑龙江省自然科学基金(青年)项目 区域战略性新兴产业成长模式与管理方法研究 (编号:QC 2011C 063);黑龙江省科技攻关项目 高新技术产业创新能力形成机理与培育路径研究 (编号:GZ 11D 209)㊂作者简介:王珊珊(1980-),女,博士/博士后,副教授,硕士生导师,研究方向:高新技术发展与战略管理;王宏起(1958-),男,博士/博士后,教授,博士生导师,研究方向:高新技术发展与战略管理㊂技术创新扩散的影响因素综述*王珊珊㊀王宏起(哈尔滨理工大学管理学院㊀哈尔滨㊀150080)摘㊀要㊀在明晰技术创新扩散的内涵基础上,对国内外技术创新扩散的研究文献进行全面的梳理,从技术创新特性及创新企业行为㊁采用者/消费者㊁网络结构㊁竞争合作㊁知识溢出㊁空间特征㊁宏观环境七个方面,综述了技术创新扩散的影响因素及其作用机理,总结出当前研究特点,并指出未来在产业创新网络的内部和外部扩散㊁政府作用于产业技术创新战略联盟创新扩散的机理方面有待进一步深入研究㊂关键词㊀技术创新㊀创新扩散㊀技术扩散㊀扩散网络中图分类号㊀F 204㊀㊀㊀㊀㊀㊀文献标识码㊀A ㊀㊀㊀㊀㊀㊀文章编号㊀1002-1965(2012)06-0197-05A Review on the Influencing Factors of TechnologicalInnovation DiffusionWANG Shanshan ㊀WANG Hongqi(School of Management ,Harbin University of Science and Technology ,Harbin ㊀150080)Abstract ㊀On clearing the meaning of technological innovation diffusion ,this paper makes literature review of domestic and foreign tech-nological innovation diffusion research.From seven aspects including the technological innovation features and innovative enterprise behav-iors ,the adopter /consumer ,the network structure ,the competition and cooperation ,the knowledge spillover ,the spatial characteristics and the macro -environment ,it summarizes the influencing factors and their working mechanism of technological innovation diffusion.Af-ter that ,it sums up the characteristics of current research and points out the questions that need further study in the future such as the inter-nal and external diffusion of industrial innovation network ,the mechanism of government roles on the innovation diffusion of industrial technology innovation strategic alliance and so on.Key words ㊀technological innovation ㊀innovation diffusion ㊀technology diffusion ㊀diffusion network0㊀引㊀言创新,主要包括技术创新㊁知识创新和管理创新,其中技术创新是一个国家/区域科技创新水平和竞争力的重要决定因素㊂技术创新的鼻祖Schumpeter 将技术进步和创新过程分为发明㊁创新和扩散三个阶段,可见,只有实现了技术创新扩散,才能够真正体现技术创新的价值㊂随着国内外关于技术创新研究的进一步深入,顺应知识经济和全球化发展要求,技术创新扩散问题日益引起国内外学者的高度重视,因而进一步明确技术创新扩散受到哪些因素的影响㊁这些因素又是如何作用于技术创新扩散的过程和效果等问题,对于加强从微观创新主体到宏观扩散环境等一体化创新扩散管理㊁提高创新扩散水平具有重要作用㊂1㊀技术创新扩散的内涵根据美国学者Rogers 提出的 创新扩散理论 ,技术创新扩散是指技术创新在一定时间内通过某种渠道第31卷㊀第6期2012年6月㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀情㊀报㊀杂㊀志JOURNAL OF INTELLIGENCE㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀Vol.31㊀No.6June㊀2012在社会系统成员中进行传播并被成员接受的过程,技术创新扩散应具备三个要素:技术创新源㊁扩散媒介㊁采纳者㊂技术创新扩散既包括技术创新的水平转移,又包括垂直转移,水平转移是指一项技术在产业中实现的规模应用,垂直转移是指技术形态到消费品形态的转变[1]㊂从研究主题来看,技术创新扩散的研究包括技术扩散㊁产品扩散㊁知识扩散等,扩散的技术创新成果包括新技术㊁新产品和新知识等;其中,技术扩散是指技术在空间传播或转移[2],产品扩散主要是通过市场运作使新产品被消费者接纳,知识扩散主要是创新合作主体之间通过知识溢出来传播知识[1];以上都属于技术创新扩散范畴,并在技术创新扩散全过程的不同阶段发挥重要作用㊂2㊀技术创新扩散的影响因素国内外学者从不同视角,对技术创新扩散的影响因素及其作用机理进行了理论分析㊁实证检验和模拟仿真,总结如下㊂㊀2.1㊀技术创新特性及创新企业行为㊀技术创新自身的特性是创新扩散最为重要的影响因素,是创新得以扩散的基本动力,首先,只有能满足目标人群某种需求的技术创新成果才能够被市场接受,从而易于扩散;其次,较高的创新性和产品性能促使技术创新成果快速扩散;再次,技术创新成果不能太复杂和难以操作,否则,就会使其所包含的隐性知识越多,从而增大扩散的壁垒[3-5]㊂创新企业是技术创新扩散的源头,创新企业的市场行为如新产品目标市场的选择和促销时机㊁传播渠道的优越性等也会影响创新产品在市场中扩散的时间和效果[6,3]㊂另外,如果具有先发优势的创新企业希望达到垄断的效果,则会降低自身产品兼容性,阻止其它小厂商的产品扩散,可见,最先开展创新企业的产品兼容性会影响没有市场优势企业的产品扩散,从而影响其自身产品的市场占有率[7]㊂可见,从技术创新自身来看,一项基于市场需求导向的创新成果,其创新性越高㊁产品性能越优,越容易扩散,但是如果创新成果复杂度过高,则会造成扩散壁垒,不利于扩散;在企业层面,市场营销决策决定了产品的市场扩散水平,从企业间的竞争来看,先行创新的企业可通过改变其产品兼容性,影响后发企业的产品扩散㊂㊀2.2㊀采用者/消费者㊀技术创新的根本目的是使一项技术及产品被众多的采用者/消费者使用,采用者/消费者特征在很大程度上决定了创新扩散效果㊂采用者不同的地位角色影响创新扩散过程与速度,杨朝峰(2006)根据采纳行为的驱动力而非采纳时间,将采用者分为领导者和追随者,认为创新扩散的速度不是单调的,而是先升后降,最后收敛于领导者采用速度[8]㊂采用者/消费者认知和偏好决定了创新(产品)最终能否被接受㊂付晓蓉等(2011)提出消费者知识对创新属性感知与消费者使用意愿间关系产生影响,进而影响创新扩散[9];Alkemade等(2005)的研究发现:消费者根据他们的偏好及社会网络中的邻居决策,决定是否购买新产品[10]㊂采用者与非采用者之间的人际传播是创新得以扩散的重要条件,这是因为采用者能够影响非采用者采用新产品的决策㊂赵新刚等(2006)认为,当一项新产品投入市场后,对价格敏感程度低的潜在采用者是率先采用创新者,通过采用者对非采用者的宣传影响新产品扩散速度,在该过程中,新产品主要是通过人际交流网络传播的,广告等大众传媒的作用不大[4]㊂然而也有学者认为大众传媒和人际交流都是重要的影响因素,只不过在技术创新扩散的不同阶段发挥不同的作用,如方亮等(2007)的研究表明:技术创新扩散在初期主要依靠大众传媒的力量,即创新通过广告的大力宣传和权威部门的认可迅速占领市场;而在发展阶段,则主要通过不断提供满足消费者需求的新产品,形成相对稳定的消费群体,通过消费者之间的交流进一步扩展市场[11]㊂此外,人员流动也是人际传播的重要形式,廖志高等(2007)按照是否使用创新技术,将消费者分为使用者和非使用者两类群体,实证发现扩散速度与两类群体之间人员流动状况有关,成员是否流动㊁是单向还是双向流动都使创新扩散速度和市场最大需求量发生变化[12]㊂上述分析可总结为:第一,采用者/消费者的地位角色决定了其对待创新的采用态度㊁采用方式㊁采用行为驱动力等采用决策的差异,进而影响创新速度;第二,是否接受创新的决策,受采用者/消费者认知和偏好的影响;第三,先期采用者通过向非采用者的人际传播,能够加速创新扩散㊂㊀2.3㊀网络结构㊀技术创新扩散活动呈现出显著的网络特征,这是因为创新者㊁采用者等扩散行为主体作为网络节点共同构成了一个复杂的创新扩散网络,网络效应的存在加快了技术创新扩散㊂具体而言,网络结构影响网络节点关联㊁扩散方式㊁扩散距离㊁扩散路径和扩散程度㊂技术创新扩散网络是具有无标度和小世界特性的复杂网络㊂李守伟等(2007)认为:无标度网络使得创㊃891㊃㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀情㊀报㊀杂㊀志㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀第31卷新易于在网络上扩散,小世界网络促使创新扩散的平均路径较短进而波及整个产业,较高的网络集聚系数使得创新被分享的程度加大[13];黄玮强等(2007)的研究也表明:在小世界网络上的创新扩散水平最高,创新扩散水平随网络随机性的增大而降低,说明扩散网络中个体派系的聚集程度决定创新最终累积采纳者比例[14]㊂网络中结构洞的存在为占据结构洞位置上的行为主体提供了控制重要资源和知识学习的机会,从而使结构洞创新扩散比网络中的其它部分更为显著,这一结论通过实证研究可以验证,例如Muñiz等(2010)发现:由于结构洞的存在,西班牙和欧盟高中技术部门扩散达到了平均以上水平,结构洞为各部门获取各种信息和竞争优势进而提高创新能力提供了机会[15]㊂创新的采用者/消费者自身又构成了一个社会网络,成为创新扩散网络中的局部网络,张晓军等(2009)认为不同的社会关系网络密度对创新扩散的影响取决于采用者对社会关系网和传媒网的依赖程度[17]㊂在采用者网络中,具有高连接度的主体往往决定了最终的创新扩散效果,这是因为他们能够影响其他潜在采用者的认知与决策,Delre等(2010)的研究表明:具有高度连接的agents对创新扩散的影响取决于他们能否告知大多数消费者,而非说服消费者采用创新[18]㊂然而,陈锟(2010)发现:种子顾客在消费者网络中的分布越分散,创新扩散所需要的时间就越短,网络平均节点度数的增加能够加速创新扩散[16]㊂在创新扩散过程中,采用者网络中异质性主体的存在及其数量会影响扩散速度,鲜于波等(2009)以技术标准扩散为例的建模仿真发现:市场上的异质性主体能降低标准扩散所需要的起始用户数,但如果某种标准拥有的较高网络效应异质性个体数量过多,会使先发优势和锁定不再成立[19]㊂综上,技术创新扩散的网络结构和关系等网络属性特征,对创新扩散的过程做出了合理的解释,同时因为网络的存在,加速了创新扩散;在创新扩散网络中,采用者/消费者作为局部网络,其网络中具有高连接度主体的信息传达㊁种子顾客的分散分布以及异质性主体的存在能够加速创新扩散㊂㊀2.4㊀竞争合作㊀从竞争视角来看,技术拥有企业间的竞争互动能够显著影响技术创新扩散的最终成败(张诚等,2009)[20];而对于两种竞争性技术或产品而言,两者之间显著的替代效应会降低各自的用户扩散速度(程鹏飞等,2010)[21]㊂在企业合作过程中,首先,合作伙伴的相似性和互补性成为创新扩散的基础,合作伙伴相似性及交流等对不同类型知识传播产生影响(Sherwood等, 2008)[22],合作伙伴互补性有利于提高市场接受度和产品创新扩散程度(Belderbos等,2006)[23]㊂然而,在现实中,市场上的创新企业或创新产品并不是单纯的竞争或合作关系,它们之间复杂多变的关系影响创新扩散的过程和效果㊂张林刚等以市场上的两类创新产品为例,认为两者之间的关系非常复杂且可能随着时间的推移而发生改变,使得创新扩散可能存在竞争㊁互利共存和捕食三种作用模式,创新扩散过程在这三种模式之间转化,进而影响扩散效果[24]㊂由以上分析可知,技术创新扩散中,竞争企业的行为以及竞争性技术或产品的替代性,会影响创新扩散的速度和结果;而合作中的创新扩散则主要受到伙伴相似性㊁互补性㊁交流等因素影响;然而,很多情况下,竞争与合作行为同时存在,这使得创新扩散过程随时间推移而复杂多变,进而影响扩散效果㊂㊀2.5㊀知识溢出㊀技术创新扩散受知识溢出的影响,从国际投资活动来看,FDI㊁出口和进口是国际技术扩散的主要渠道,会产生显著的溢出效应,进而提高东道国的学习能力[25-27],如Branstetter(2006)研究了日本在美国FDI的溢出情况,发现:FDI和本国企业海外投资都是国际技术扩散的渠道[28];张经强(2009)的研究也表明:通过双边贸易产生知识溢出,可以使进口国在国际技术扩散中受益[29]㊂然而,溢出效应取决于知识主体间的知识差距及其吸收能力㊂如果知识主体之间的高低位势差距过大,将使知识扩散缺乏动机和动力,从而影响扩散速度和程度(李莉等,2007)[30];同时,知识主体之间的文化冲突和差异等因素阻碍知识扩散(孙耀吾等, 2010)[31]㊂从吸收能力来看,吸收能力越强的知识主体和地区,将放缓知识溢出空间衰减的速度,从而获得更多的知识溢出(陈傲等,2010)[32],进而加速创新扩散㊂窦丽琛等(2004)的研究也表明:中国仅有少数较发达地区能够享受到更先进地区的技术溢出效应,落后地区未能很好地获取溢出效应主要是受制于有限的 吸收能力 [33]㊂可见,知识溢出是技术创新扩散的重要方式,投资活动和双边贸易等扩散渠道会产生显著的知识溢出效应进而加快了技术创新扩散,同时扩散活动各方的知识差距和吸收能力是影响知识溢出和扩散效应的重要因素㊂㊀2.6㊀空间特征㊀从地理位置来看,空间距离越短,越有利于技术创新扩散,因此集聚能够有效地促进扩散㊂MacGarvie(2005)利用专利引用量测度国际技术扩散,认为技术与资源在空间上邻近以及语言相通等㊃991㊃㊀第6期㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀王珊珊,等:技术创新扩散的影响因素综述因素有助于国际技术扩散[34]㊂Mari等(2004)界定了技术扩散的空间尺度,提出高新技术企业在空间上邻近可以加快扩散速度[35]㊂从区域内部构成体系来看,各城市规模不同造成城市功能等级的差异,形成创新扩散的空间梯度,促进创新沿梯度扩散,徐雪琪等(2008)的实证研究发现长三角城市间的创新扩散强度与城市规模等级之间存在很强的空间关联性,创新在各城市间呈现等级扩散的模式,加强城市间的交通㊁信息网络建设有利于加速创新扩散[36]㊂各区域之间的差异性也对技术创新扩散产生重要影响㊂除了空间距离因素,技术创新扩散还受到由空间距离所带来的各区域产业联系和技术差距的影响㊂周密认为,技术空间扩散受到空间距离㊁技术差距和产业联系等因素影响,其中空间距离所产生的空间依赖性和产业联系与技术扩散正相关,技术差距与技术扩散负相关;从影响程度上看,产业联系对技术扩散的影响最大,空间距离对技术扩散的影响次之,技术差距对技术空间扩散的影响最小[37]㊂根据上述分析,地理上的接近有助于创新扩散,创新通常沿着空间梯度扩散,不同区域的空间距离㊁产业联系和技术差距,都会对创新扩散产生重要影响㊂㊀2.7㊀宏观环境㊀从宏观环境来看,宏观经济增长对于技术或产品用户扩散速度有显著的正向影响(程鹏飞等,2010)[21]㊂朱恒源等也发现,在一个社会经济系统中,经济发展水平越高㊁人口流动性越大,创新扩散的速度越快;而地区的二元经济结构特征越强㊁人口受教育程度越高,创新越不易扩散[38]㊂另外,一个地区的政策制度㊁法规以及市场规范程度等会对创新扩散产生重要的影响(陈劲等, 2008)[3]㊂周密提出,作为技术扩散形成的要素之一,政府技术投入对技术扩散具有重要意义[37]㊂赵骅等也认为政府要有层次性地对参与到技术创新扩散活动中的企业给予政策与资金方面的支持,形成一种层次鲜明㊁有差别的支持结构,才能更有效地激励创新扩散[39]㊂随着世界各国尤其是发达国家对于环境管制及可持续发展的要求越来越高,学者们也越来越关注绿色技术创新扩散问题,多数学者认为全球环境管制与绿色技术扩散密切相关(童昕等,2007)[40];还有学者提出只有政府执行严格的排放限制政策时,才能促进污染控制技术的快速扩散(Popp,2010)[41]㊂另外, Los等(2009)以汽车二氧化碳排放技术为例,研究发现技术扩散率根据汽车细分市场(如汽油和柴油)不同而具有差异性[42]㊂从宏观层面来看,经济发展水平㊁人口流动㊁市场环境等因素影响创新扩散速度和效率,而政策法规等措施通过对创新扩散的激励和规范,促进了公益性或产业重要技术创新的扩散㊂3㊀结㊀语技术创新扩散受到了国内外学者的广泛关注,取得了丰富的研究成果㊂与技术创新扩散影响因素相关的研究有如下特点:一是在研究问题上,覆盖了从技术㊁产品到市场的技术创新扩散全过程管理;二是研究对象的多元化,包括产业(网络)㊁集群㊁联盟㊁业㊁新产品㊁采纳者/消费者等,既体现了技术创新扩散的宏观特征,又能考虑微观个体行为;三是在研究方法上,注重通过定性描述㊁定量分析㊁建模仿真和实证研究,更加深刻㊁准确地揭示各种因素影响技术创新扩散的方式与规律㊂根据国家高新技术产业创新升级及战略性新兴产业发展与突破要求,未来将在以下方面加强研究:一是从提升产业创新能力和竞争力出发,结合国家创新战略,深入研究产业创新网络的内部和外部扩散规律与关键影响因素二是随着产业创新以产业技术创新战略联盟为牵引的趋势日益增强,还需要从宏观层面,进一步揭示政府对联盟创新扩散的作用机理,为政府加强产业技术创新战略联盟的技术创新扩散㊁推动产业整体创新提供理论支持㊂参考文献[1]㊀纪占武,卢锡超.产业技术扩散的知识重构研究[J].科学学与科学技术管理,2010(8):33-37[2]㊀黄静波.国际技术转移[M].北京:清华大学出版社,2005:15-16[3]㊀陈㊀劲,魏诗洋,陈艺超.创意产业中企业创意扩散的影响因素分析[J].技术经济,2008,27(3):37-45[4]㊀赵新刚,闫耀民,郭树东.企业产品创新的扩散与采纳者的行为决策模式研究[J].中国管理科学,2006,14(5):98-103 [5]㊀王开明,张㊀琦.技术创新扩散及其壁垒:微观层面的分析[J].科学学研究,2005,23(1):139-143[6]㊀Delre S A,Jager W,Bijmolt T H A,Janssen M A.Targetingand Timing Promotional Activities:An Agent-based Model for the Take off of new Products[J].Journal of 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2010(08)2.黄静波国际技术转移 20053.陈劲;魏诗洋;陈艺超创意产业中企业创意扩散的影响因素分析[期刊论文]-技术经济 2008(03)4.赵新刚;闫耀民;郭树东企业产品创新的扩散与采纳者的行为决策模式研究[期刊论文]-中国管理科学 2006(05)5.王开明;张琦技术创新扩散及其壁垒:微观层面的分析[期刊论文]-科学学研究 2005(01)6.Delre S A;Jager W;Bijmolt T H A;Janssen M A Targeting and Timing Promotional Activities:An Agent-based Model for the Take off of new Products[外文期刊] 2007(08)7.鲜于波;梅琳间接网络效应下的产品扩散--基于复杂网络和计算经济学的研究 2009(01)8.杨朝峰基于领导者一追随者混合结构模型的创新扩散实证研究 2006(09)9.付晓蓉;赵冬阳;李永强消费者知识对我国信用卡创新扩散的影响研究[期刊论文]-中国软科学 2011(02)10.Alkemade F;Castaldi C Strategies for the Diffusion of Innovations on Social Networks 2005(1-2)11.方亮;龚晓光;肖人彬技术创新扩散的元胞自动机仿真[期刊论文]-系统仿真技术 2007(02)12.廖志高;徐玖平一类技术创新扩散模型的稳定性及其应用[期刊论文]-系统工程理论与实践 2007(08)13.李守伟;钱省三;沈运红基于产业网络的创新扩散机制研究[期刊论文]-科研管理 2007(04)14.黄玮强;庄新田网络结构与创新扩散研究[期刊论文]-科学学研究 2007(05)15.Mu(n)iz A S G;Raya A M;Carvajal C R Spanish and European Innovation Diffusion:A Structural hole Approach in the Inputoutput Field 2010(01)16.陈锟种子顾客的网络分布对创新扩散的影响[期刊论文]-管理科学 2010(01)17.张晓军;李仕明;何铮社会关系网络密度对创新扩散的影响[期刊论文]-系统工程 2009(01)18.Delre S A;Jager W;Bijmolt T H A;Janssen M A Will it spread or not The Effects of Social influences and Network Topology on innovation diffusion 2010(02)19.鲜于波;梅琳主体异质性、小世界网络与间接网络效应下的标准扩散--基于agent计算建模的研究 2009(03)20.张诚;林晓技术创新扩散中的动态竞争:基于百度和谷歌(中国)的实证研究[期刊论文]-中国软科学 2009(12)21.程鹏飞;刘新梅经济增长、替代效应及规制对电信发展的影响--基于创新扩散的视角 2010(01)22.Sherwood A L;Covin J G Knowledge Acquisition in University-industry alliances:An empirical Investigation From a Learning Theory perspective[外文期刊] 2008(02)23.Belderbos R;Carree M;Lokshin B Complementarity in R&D Cooperation Strategies[外文期刊] 2006(04)24.张林刚;陈忠基于Lotka-Volterra模型的创新扩散模式研究[期刊论文]-科学学与科学技术管理 2009(06)25.Hamida L B;Gugler P Are There Demonstration-related Spillovers from FDI:Evidence from Switzer 2009(05)26.Bwalya S M Foreign Direct investment and Technology Spillovers:Evidence From Panel Data Analysis of Manufacturing Firms in Zambia[外文期刊] 2006(02)27.Ciruelos A;Wang M International Technology Diffusion:Effects of Trade and FDI 2005(04)。
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THE ICT DIFFUSION: A SPATIAL ECONOMETRIC APPROACHAndrea Bonaccorsi Dipartimento di Sistemi Elettrici ed Automazione, Facoltà di Ingegneria, Università di Pisa Via Diotisalvi 2 – 56126 Pisa E-mail: bonaccorsi@sssup.it Lucia Piscitello Dipartimento di Ingegneria Gestionale, Politecnico di Milano Piazza Leonardo da Vinci 32 – 20133 Milano E-mail: lucia.piscitello@polimi.it Cristina Rossi Scuola Superiore Sant’Anna P.za Martiri per la Libertà 33 - 56127 Pisa E-mail: cristina.rossi@sssup.itAbstract Several empirical studies highlight severe disparities among geographical areas in the diffusion of ICT that affect not only developed vs. developing countries (Global Digital Divide) but also regions within the same country (Local Digital Divide). Economic scholars have investigated the determinants of these disparities but comprehensive conclusions are far to be reached. This paper contributes to the literature by modelling the level of ICT diffusion at the Italian regional level (NUT3) using spatial econometric techniques. Namely, two main research questions are addressed: (i) do Italian regions exhibit significant differences in their patterns of ICT diffusion? (ii) if so, how local structural specificities interact with spatial effects in explaining these disparities? According to recent approaches in the metrics of ICT, the empirical analysis uses domain name registrations by firms in 2001 as a proxy of ICT diffusion at the local level. The results show that sectoral composition, technological endowment and absorptive capacity at the regional level, as well as firms’ characteristics, do play a crucial role. In addition, pure spatial effects contribute to regional disparities. JEL codes: O18, O33, C21 Keywords: Digital Divide, ICT diffusion, spatial econometricsWe gratefully acknowledge Prof. Franco Denoth, director of IIT-CNR, Maurizio Martinelli, coordinator of the project at the Registration Authority, Irma Serrecchia and all the staff of IIT-CNR for the invaluable help in data collection and management. The authors wish to thank also Alessandro Scateni for the assistance in the construction of the data base, and participants in the First International Congress of Econometrics and Empirical Economics, Venice, 2005, for useful comments provided to earlier versions.1Understanding the interplay between innovation, technology and productivity growth is the foundation for projecting the future economic growth rate of a country, a region, or the world (Gordon, 2004).1. Introduction The notion that Information and Communication Technology (ICT) would have reduced the economic importance of geographic distance has been proposed with energy in the post-Internet literature (Cairncross, 2001). According to this view, the New Economy would work in a space rather than a place, cost of transport would be drastically reduced, distance would be less important, and peripheral regions would benefit from opportunities that were not available in the economy based on manufacturing industry (Negroponte, 1995; Kelly, 1998; Quah, 2000). Since ICT are mostly based on immaterial and human capital investment, regions or areas that have historically suffered from isolation, large cost of transportation, or lack of physical private and public infrastructure might find new paths for growth. Consequently, according to this view, the concentration of income opportunities and wealth should decrease over time (e.g. Compaine, 2001). Although other predictions were also present in the debate over the impact of the digital economy (e.g. Norris, 2002; UNDP, 2001), this view was largely dominant. The reality is not so rosy. Not only there are huge disparities in the intensity with which ICT are adopted across countries, but also there are still large differences within industrialised countries. Indeed, differences in economic development still shape the rate of the diffusion of these technologies, at the firm, regional and country level. The reasons behind these stylised facts have been investigated at length in recent times. This paper contributes to the literature in several ways. First, it focuses on intra-national or regional differences, which is a much less explored dimension of the Digital Divide. Second, it uses a new metric for the diffusion of ICT, namely the number of second level Internet domain names, registered under the ccTLD “.it”. Finally, it explicitly combines the analysis of determinants with a spatial econometric approach.2The paper is organised as follows. Section 2 surveys the literature on the Digital Divide and the relation between local development and diffusion of ICT. Section 3 describes data and methodology. Section 4 contains the description of the model and the empirical results. Section 5 summarises the main conclusions of the paper.2. Local Digital Divide: the relation between development and ICT diffusion The conceptual link between economic development and ICT diffusion is a widely researched issue in the economic literature. It may be claimed that, given their nature ICT allow to overcome territorial peripherality. Differently from traditional heavy and light manufacturing investment, ICT may increase regional attractiveness as a strategic location factor, thus enhancing territorial competitiveness (Gillespie et al., 1989; Kraemer and Dedrick, 1996; Steinmuller, 2001; Camagni and Capello, 2004). The successful experiences of Ireland and India as emerging regions in the off-shore of software services, due to the availability of efficient communication infrastructures, is often quoted. Contrary to most expectations, however, the overall empirical reality is one of large geographic differences in the rate of diffusion of ICT, so that disparities and inequalities1 seem to be reinforced, rather than reduced, by these technologies. Most studies have revealed astonishing differences in Internet and computer penetration between North America and Europe, on the one side, and African and Asian countries on the other (see Chinn and Fairlie, 2004 for a comprehensive survey of this literature). These large disparities have been explained referring mainly to differences in income, but also to human capital, telecommunication infrastructures (Dasgupta et al., 2001; Oyelaran-Oyeyinka and Lal, 2003; Pohjola, 2003; Wallsten, 2003), demographical variables and regulatory regimes (Wallsten, 2003)2. Although these explanations are rather convincing, it is puzzling why the evidence of a process of convergence of less developed countries in the diffusion of these technologies is still scant.According to OECD (2001) Digital Divide refers to the gap between individuals, households, businesses and geographic areas at different socio-economic levels with regard both to their opportunities to access information and communication technologies (ICTs) and to their use of the Internet for a wide variety of activities. 2 In Japan the cost of monthly connection to broadband services is estimated at 0,9% of the average income, while the same ratio is 1.207 % in Bielorussia and 9.116 % in Camerun (eEspana, 2004). 31Less investigation has been devoted to the local dimension of the phenomenon as indeed digital inequalities do not divide only developed from developing countries but also regions within the same country (Local Digital Divide, see for instance Gareis and Osimo, 2004; Ramsay, 2004). Both developed and developing countries suffer from severe regional disparities in ICT diffusion. Evidence has been provided with reference to United States (NTIA, 2002; Mills and Whitacre, 2003), Canada (Dryburgh, 2001), Portugal (Nunes, 2004), Spain (Billon Curras and Lera Lopez, 2004), Italy (Bonaccorsi et al., 2002; Assinform, 2004), China (Qingxuan and Mingzhi, 2002; Wensheng, 2002). A clear-cut stylised fact that emerges from this literature is that regional disparities are larger and more persistent when compared to cross country differences, at least within industrialised nations. For example, with respect to Italy, Bonaccorsi et al. (2002) found that geographic concentration of the diffusion of Internet is much higher than concentration in population or income. Hence, it seems that ICT does not reduce regional disparities, but rather reinforces them. Empirical works show that determinants of local inequalities relate to disparities in economic, social and demographic aspects. In particular, differences in the spatial diffusion of ICT have been explained in terms of differences in technological levels, infrastructural endowments (Marrocu et al., 2000; Iammarino et al., 2004) and local spillover effects (Jaffe et al., 1993; Audretsch and Feldman, 1996; Galliano and Roux, 2004). However, local inequalities might be influenced also by spatial factors. In a recent study, Nunes (2004), investigating the geography of top level domain names in Portugal (.pt), has proposed that Internet might contribute to reinforce the tendency to territorial disintegration, promoting geographic disparities in a more pronounced way than is the case in the real economy space. Specifically, he found that the role of ICT to overcome spatial inequalities in Portugal is less important than expected, since these technologies are deeply influenced by the existing spatial structure rather than changing it. According to the most recent studies, mainly framed within the models of technology diffusion (Geroski, 2000), we distinguish several groups of factors which potentially influence the territorial diffusion of ICT(for an excellent recent survey, see OECD, 2004). A first category of factors, which are positively related to ICT diffusion, concerns the local technological endowment and the relevant absorptive capacity. Specifically, absorptive capacity refers4to both the firms’ ability to assess technological opportunities (which depends on its endowment of human and knowledge capital, Cohen and Levinthal, 1989), and also to learning effects. The latter may arise from earlier use of ICT or a predecessor of a specific ICT element which already embodies constituent elements of later applied, more advanced vintages (McWilliams and Zilberman, 1996). Additionally, according to Hollenstein (2004: p.41) “these aspects of absorptive capacity refer to the standard epidemic model of technology diffusion and to the relevant information spillovers from users to non users of the technology. This model basically states that a firm’s propensity to adopt a technology at a certain point in time is positively influenced by the present (or lagged) degree of its diffusion in the economy as a whole or in the industry to which the firm is affiliated to”. A second category of variables refers to market characteristics. Specifically, the sectoral specialisation of the region has largely been shown to impact significantly upon the diffusion of ICT (Pohjola, 2003). Likewise, firms’ characteristics have been traditionally employed as explanatory variables in most studies of diffusion. In particular, firm’s size captures the Schumpeterian hypothesis about the positive relation between innovativeness and dimensional scale. The same holds for firm age, although the theoretical arguments are not conclusive (positive experience effects vs. negative adjustment cost effects in case of older firms, see Lal, 2001; Hollenstein, 2004). The diffusion of ICT may also be affected by market conditions under which firms are operating, particularly the competitive pressure they are exposed to. In markets where competition is stronger firms are expected to be more inclined to innovative activities or rapid technology diffusion (Porter, 1990; Majumdar and Venkataraman, 1993; Feldman and Audretsch, 1999; Hollenstein, 2004) Finally, we explicitly take into account the role that spatial externalities play in the current thinking about innovative activity (see Audretsch, 2003).53. Methodology and data 3.1. Domain names as a proxy for ICT diffusion The term ICT encompasses a wide range of technologies. According to the Canadian Statistic Bureau it includes desktop and laptop computers, software, peripherals and connections to the Internet that are intended to fulfil information processing and communications functions3. Such a variety poses severe methodological problems as measuring the level of territorial diffusion of these assets? According to Pohjola (2003), two kinds of metrics reveal disparities in ICT diffusion across countries: data on ICT equipment and its use, as well as indicators of ICT spending. However, most of the studies that have analysed geographical inequalities at the international level have identified ICT with the Internet, referring to the number of Internet hosts (OECD, 2001; Kiinski and Pohjola, 2002) and of Internet users (Norris, 2002, NTIA, 2002)4, although rendering the problem of differences in ICT diffusion to the simple Internet access is misleading (Oden and Rock, 2004). As a matter of fact, data on Internet hosts are easily available and highly reliable (Press, 1997; Wolcott et al., 2001) 5. Anyway, this metric suffers from two main shortcoming: data are gathered only at the national level and they do not provide any information about the adopters. Analyses at a regional level benefit from the availability of larger sets of indicators, ranging from the share of electronic productions to mobile phones; survey data are also available6. Recently, the use of domain names as a proxy of Internet diffusion has been proposed (Zook, 2000; Zook et al., 2004). Domains may be a valid proxy for ICT diffusion, mainly because they operationalise the intention to actively supply contents through the Net. Specifically, those who register a domain name uses the Internet in a more conscious manner aiming not only at demanding but also at adding contents to it7.http://www.statcan.ca/english/freepub/81-004-XIE/def/ictdef.htm An analysis of cross-country diffusion of personal computers is in Caselli and Coleman (2001). 5 For instance every six months Network Wizard publishes the results about all the TLD on its web site, whereas the RIPE () publishes the data about the ccTLD in its area (Europe, North Africa, Middle East) monthly. Hosts belong to the so called endogenous metrics that are obtained in an automatic or semiautomatic way from the Internet itself (Diaz-Picazo, 1999). The organisations that manage the different ccTLD and gTLD perform the hostcount under their TLD on a regular basis and provide these data on the Web or by ftp. 6 The bi-annual survey A Nation on line, conducted on more than 3,000 US citizens (NTIA, 2002), collects data on the number of PC purchased by families and on the activities they carry on through the Internet. 7 Domain grabbing must to be taken into account. However, this phenomenon does not affect our data, as the unit of analysis is the registrant, rather than the domain: multiple registrations have been discarded from the database.436In general, the registration of a domain name by a firm is the first step towards the set up of a Web site through which presenting the offering or even undertaking electronic commerce activities. Therefore, domains provide an underestimation of the ICT diffusion8 as: (i) ICT diffusion does not necessarily require registering a domain; and (ii) the Internet Service Providers often offer their users room (on their servers) for adding new contents. Thus, domains constitute a lower bound as any registrant is unquestionably an ICT adopter. Additionally, every domain name is uniquely associated to a registrant whose geographical location and nature are unambiguously recorded in the databases of the organisations that manage the different ccTLD (Mueller, 1998; Grubesic, 2002). The availability of information at the sub-national level makes domains a valid metric to explore the territorial dimension of ICT diffusion while data on the nature of the registrants allow to take into account different diffusion determinants for different population of potential adopters. This paper makes use of domain name registrations by Italian firms as a proxy for ICT diffusion at the NUTS3 level (103 regions). During years 2002-2003, the Institute of Informatics and Telematics (IIT) of the National Research Council (CNR), Sant’Anna School of Advanced Studies and the University of Pisa have built a database that contains, at a sub regional level, the registrations of domain names by different categories of actors (individuals, business firms, universities and research centres, third sector associations and public administration bodies). Data were extracted from the databases of the registrations under the ccTLD “.it” that are managed by the Italian Registration Authority (RA) hosted by IIT. A total number of 500,000 domain names have been inspected for classification, multiple names registered by the same registrant have been carefully checked and eliminated.It is worth observing that hosts suffer from the same drawback. Indeed, the hostcount programs do not reach machines protected by firewalls and private networks (Intranets). The use of dynamic IP addresses by ISPs should be also taken into account. In addition, they are also prone to overestimation due to several factors such as the association of multiple IP addresses to the same computer. 783.2. The empirical evidence on ICT diffusion from the Italian case In order to use domain name registrations as a proxy for the level of ICT diffusion, penetration rate in each region has been calculated as the percentage of firms in the region that have at least a domain name registered in the Registration Authority databases as in July 2001. Table 1 summarises the descriptive statistics of the variable.Table 1-ICT diffusion: descriptive statisticsICT DiffusionNo. 103Min 1.2Max 9.1Mean 3.76Std. Dev. 1.65Skewness 0.42Kurtosis 2.72Data highlight that the level of ICT diffusion in Italy is quite low with an average penetration rate less that 4%. Table 2 reveals severe geographical disparities that mirror inequalities in the economic development emerging both among and within geographical macro-areas. No Southern region ranks in the top fifty, the best performing region in the South ranks 55th, only eight Northern regions rank below that position. Conversely, all the twenty worst performing regions are located in the South.Table 2-ICT diffusion in macro-areasArea North Centre South TotalNo. 46 21 36 103Mean 4.76 4.40 2.11 3.76Std. Dev. 1.31 1.29 0.66 1.65Kruskal Wallis Test – p value0.000Indeed, the penetration rate is positively correlated with per capita income and added value per employee (table 3). Nevertheless, registrants are more concentrated than firms and of income.Table 3-ICT diffusion and economic development: Pearson correlations and Gini’s concentration indexesPearson correlations Added value per employee Income per inhabitant 0.45 0.78 *** ***Gini’s indexes Firms registering a domain Number of firms Income 0.573 0.421 0.4588Following the literature on spatial distribution of innovation (Audretsch and Feldman, 1996; Audretsch, 2003), we expect spatial dependence to exist between the observations. Specifically, “spatial dependence in a collection of sample data observations refers to the fact that one observation associated with a location which we might label i depends on other observations at locations j≠i” (Le Sage, 1998, p.3). Table 4 reports results of tests normally used for detecting spatial dependence9. ICT Diffusion is the percentage of firms that have registered at least a domain name in each region as in 2001. All the three tests confirm the existence of spatial dependence so that we can conclude that the diffusion of ICT by each region i is related to the diffusion in other regions j≠i, thus highlighting the existence of knowledge spillovers.Table 4-Spatial dependence tests for the dependent variable (ICT Diffusion). Note: ° two-tail test; *** significant at p<.01Moran’s I ICT Diffusion Geary's c ICT Diffusion Getis & Ord's G ICT DiffusionI 0.589 c 0.480 G 0.053E(I) -0.010 E(c) 1.000 E(G) 0.044Sd(I) 0.064 Sd(c) 0.080 Sd(G) 0.002z° 9.385 z° -6.494 z° 6.001*********4. Econometric models of territorial ICT diffusion We first run a model where the dependent variable, ICT Diffusion, is regressed against a set of explanatory variables that are proxy for the absorptive capacity, the regional technological endowment, the competitive pressure, the firms’ characteristics and the sectoral composition of the region (see Table 5). Table 6 reports their statistical properties and correlations.The proximity matrix W has been constructed using the concept of contiguity between regions. Therefore, it is a 103x103 matrix that has zeros on the main diagonal, rows that contain zeros in positions associated with non contiguous observational units and ones in positions reflecting neighbouring units.99Table 5- Specification of dependent and independent variablesVariables DEPENDENT VARIABLE ICT Diffusion EXPLANATORY VARIABLES Absorptive capacity PATENTS PUBLICATIONS Competition DISTRICTS Firms' characteristics AGE Sectoral Composition STRUCTURE Technological Endowment IT_EXPENDITURE INFRASTRUCTURE Ratio of IT expenditure in each region and the number of firms in that region Facilities and networks for Telephony and Telematics (Index of endowment, Italy =100) Assinform/NetConsulting Elaboration Istituto Tagliacarne Percentage of firms in Agriculture. It is a dummy variable that assumes value 0 if the region is below the national average, 1 otherwise. Infocamere - Elaboration Percentage of firm aged less than 10 years Unioncamere - Elaboration Percentage of districtual local units Infocamere - Elaboration Ratio of the number of patents granted in each region in the period 19911999 by the USPTO and the number of firms in that region Ratio between the number of scientific publications by University researchers in each region and the number of firms in that region USPTO - Elaboration ISI Citation Index databases Elaboration Percentage of firms that have registered at least a domain name Registration Authority for the ccTLD “it” - Elaboration Description SourceTable 6-Statistical properties of the explanatory variables and correlation matrixVariable Min Max Mean Std. Dev. Obs. AGE PATENTS INFRASTRUCTURE PUBLICATIONS IT_EXPENDITURE DISTRICTS AGE. 33.60 55.90 44.92 3.93 103 1.000 -.037** .276 .084 .173 -.288** PATENTS 0.00 2.43 0.26 0.36 103 1.000 .428*** .305** .307** .256* INFRASTRUCTURE PUBLICATIONS IT_EXPENDITURE DISTRICTS 17.30 0.00 1092.23 0.00 345.20 4.17 266667.10 100.00 87.03 0.39 18147.52 27.96 51.17 0.74 33204.24 35.35 103 103 103 1031.000 .378*** .589*** .227**1.000 0.229 0.0011.000 0.0161.000Additionally, as we already identified the existence of spatial dependence for the dependent variable (see Table 4), the model must include the spatially lagged dependent variable among the explanatory variables. In other words, we estimate the following mixed regressive-spatial autoregressive model:ICT Adoptioni = ρW1 ICT Adoptioni + Xβ + εThe parameter ρ would reflect the spatial dependence inherent in our sample data, measuring the average influence of the diffusion in neighbouring regions on the diffusion in each region. The parameters β reflect instead the influence of the explanatory variables X.10The results from the mixed regressive-spatial autoregressive model are obtained again throughmaximum likelihood (using Stata) and are reported in Table 7. It emerges that the dependent variableexhibits a spatial dependence as the estimate of ρ on the spatial lagged variable is positive andsignificant.Table 7-Results from the mixed regressive-spatial autoregressive modelCoef.zP>|z| Absorptive capacityPATENTS 0.505*1.8300.068PUBLICATIONS 0.270**2.2300.026 CompetitionDISTRICTS 0.008***2.8700.004 Firms' characteristicsAGE -0.095***-3.7500.000 Sectoral CompositionSTRUCTURE -0.560***-2.9000.004 Technological EndowmentIT_EXPENDITURE 0.000**2.3700.018INFRASTRUCTURE 0.013***5.5100.000_cons 6.005***4.9200.000rho 0.032***2.9700.003 No. obs. 103Wald test of rho=0: chi2(1) = 8.834 (0.003)Likelihood ratio test of rho=0: chi2(1) = 8.473 (0.004)Lagrange multiplier test of rho=0: chi2(1) = 8.460 (0.004)Acceptable range for rho: -1.232 < rho < 1.000Log likelihood -123.720Moran’s I I E(I) Sd(I) z°residuals 0.380-0.010 0.0646.131 ***Notes: *** significant at p<..01, ** significant at p<.05, * significant at p<.10, ° two-tail testThe results also indicate that all of the explanatory variables exhibit a significant effect on thedependent variable we wished to explain, that is the penetration rate of registered domain.Finally, the Moran’s I test on the residuals from the mixed regressive-spatial autoregressive model(which is reported at the bottom of Table 7) highlights that the inclusion of the spatial lag term(ρW1ICT Diffusion) does not eliminate spatial dependence in the residuals of the model. Therefore,the final model estimated is a general spatial model (Anselin, 1988):ελεβρ+ =++=uW uXAdoption ICTWAdoptionICTi21Such a model has been estimated using Matlab libraries for spatial econometrics, as indeed Stata didnot allow us to run it10. The estimates confirm the high significance of all the explanatory variables,and the overall fit of the model. Specifically, as expected, ICT diffusion at the regional level ispositively influenced by: absorptive capacity (PATENTS and PUBLICATIONS are both positive andsignificantly different from zero), technological endowment (both IT_EXPENDITURE andINFRASTRUCTURE are positive and significantly different from zero), competition level(DISTRICTS is positive and significant at p<.01), firms’ characteristics (AGE is significant at p<.01,meaning that younger firms are more keen to register a domain), and sectoral composition(STRUCTURE is negative and significant at p<.01).This model produces also estimates for ρ, which is positive and significantly different from zero, thusconfirming the existence of spatial dependence for the dependent variable, while λ does not come outsignificant.Table 8-Results from the general spatial modelCoef.tz-probabAsymp.Absorptive capacity 0.489 * 1.813 0.0690.0072.690PATENTS 0.288***PUBLICATIONSCompetition 0.006 ** 2.270 0.023DISTRICTSFirms' characteristics -0.061 *** -2.626 0.008AGESectoral Composition -0.443 ** -2.508 0.012STRUCTURETechnological Endowment 0.000 *** 3.801 0.0000.0004.645IT_EXPENDITURE 0.010***0.0013.287***_cons 3.9440.0003.313rho 0.342***0.2281.206lambda 0.046No. obs 103R-squared 0.809Adj R-squared 0.795Log likelihood -19.774Notes: *** significant at p<.01, ** significant at p<.05, * significant at p<.1010 It is worth observing that we relied on the same W=W1=W2 for both the spatial lag and error correlationterms, and results are reported in Table 8.5. ConclusionsThis paper contributes to the literature on ICT diffusion in several ways.First, it corroborates some robust findings in the literature. We find that variables that describe the vitality of general economic activity are relevant. Economic environments with a low turnover of firms and traditional economic activities are less vibrant in ICT diffusion, that is the larger the share of firms in the agriculture sector and the proportion of firms older than 10 years, the lower the intensity of Internet use at advanced level. This general effect is reinforced by a specific technological effect related to ICT. Indeed, the higher the expenditure in Information Technology at local level, the larger the probability to make advanced use of Internet. Also, an index of technological endowment measured with respect to the telecommunication network has a positive and significant effect.These findings corroborate the notion that very traditional, highly “material” investments do play a great role in explaining the Local Digital Divide. As it was anticipated in the literature on telecommunication investment (Biehl, 1982; Gillespie et al. 1989; Kraemer and Dedrick, 1996), regional development may be adversely affected by disparity in the level of infrastructure. Contrary to the expectations, the spatial diffusion seems to follow the existing geography of development, rather than dramatically changing it. Our results are also consistent with existing evidence on the geographic concentration of ICT production and differences in the diffusion of ICT by firms in Italy. Iuzzolino (2003) examined the geographic concentration of all sectors related to products and services in ICT using Ellison and Glaeser (1997) indexes and found evidence of strong agglomeration effects (see also Pagnini, 2002). Fabiani et al. (2003) found extremely large differences between firms in the South of Italy and in the North and Centre in the rate of diffusion of almost all ICTs, while Iammarino et al. (2004) highlight the same divide as the production of ICT is concerned. It is true that our data do not capture the structure of supply of ICT, but rather the structure of demand or utilisation. Firms are only part of the diffusion process as described by our data on domain names. At the same time, it is clear that general economic factors and the localisation and activity of firms in these industries strongly influence the utilisation in the business sector, in households and in society at large.。