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951.
This article presents an innovative approach to establish the quality and credibility of Volunteered Geographic Information (VGI) such that it can be considered in Land Administration Systems (LAS) on a Fit for Purpose (FFP) basis. A participatory land information system can provide affordable and timely FFP information about land and its resources. However, the establishment of such a system involves more than just technical solutions and administrative procedures: many social, economic and political aspects must be considered. Innovative approaches like VGI can help address the lack of accurate, reliable and FFP land information for LAS, but integration of such sources relies on the quality and credibility of VGI. Verifying volunteer efforts can be difficult without reference to ground truth: a novel Trust and Reputation Modelling methodology is proposed as a suitable technique to effect such VGI data set validation. This method has been applied to successfully demonstrate that VGI can produce accurate and reliable data sets which can be used to conduct regular systematic updates of geographic information in official systems. It relies on a view that the public can police themselves in establishing proxy measures of VGI quality thus facilitating VGI to be used on a FFP basis in LAS.  相似文献   
952.
Understanding the relationship between China's urbanization and economic development on a provincial scale is of profound theoretical and practical significance.Based on data from 124 countries or regions throughout the world and 31 provinces or autonomous regions in China,applying improved methods using the quadrant map approach,this paper analyzed the spatial pattern of the relationship between China's urbanization and economic development level.The study identified the following results.(1) The 31 province-level regions fall into six categories:only one region is in the category of sharp over-urbanization,3 regions are in medium over-urbanization,11 slight over-urbanization,8 basic coordination,one medium under-urbanization,and seven slight under-urbanization.(2) There are significant regional differences on a provincial scale in the relationships between urbanization and the level of economic development.(3) The provincial pattern of urbanization and economic development is significantly different between east and west.The eastern coastal areas are mainly over-urbanized,while the central and western regions are mainly under-urbanized.(4) The relationship between urbanization and the level of economic development is similar to the Matthew effect.Hence,two important insights are proposed.First,the phenomenon of over-urbanization in some developed regions should be viewed with some concern and vigilance.Second,urbanization needs to be speeded up moderately in the central and western regions.  相似文献   
953.
震级频度关系的Gutenburg-Richter公式近年来受到了挑战,一些学者在不同条件下都发现了b值的非线性表现。本文利用自己装配的实验系统对围压下岩石破裂声发射活动的震级频度关系和时间序列特征进行了研究。实验表明AE事件的震级频度关系在某个中强震级K′之前基本符合b值规律,其b值的大小与破裂方式有关。在摩擦滑动中AE序列具有低b值的特征。从K′起震级频度关系出现明显的非线性现象。根据非线性表现的不同,可将其分为第一型和第二型两类。在AE序列中,也存在着“特征震级”的现象  相似文献   
954.
The reaction with the OH radical constitutes the singlemost important removal process for most organiccompounds found in the atmosphere. Efforts to measurethe OH radical rate constants of all troposphericconstituents remain incomplete due to the largevariety of primary emitted compounds and theirtropospheric degradation products.Based on the measured rate constants of 250molecules with the OH radical, a structure-activityrelationship (SAR) for OH reactions has beendeveloped. The molecules used in the dataset includemost classes of tropospheric compounds (includingalkanes, alkenes, and oxygenated hydrocarbons), withthe exception of aromatic and halogen-containingcompounds. Using a new parameterization of themolecular structure, the overall agreement betweenmeasured values and those estimated using the SARdeveloped in this study is usually very good, with10% of the molecules showing deviations larger than50%. In particular, the estimated rate constants ofethers and ketones are in better agreement withexperimental data than with previous SARs (Kwok andAtkinson, Atmos. Environ. 29, 1685–1695,1995). Rate constants of organic nitrates werenot well described by the SAR used in thisstudy. The basic assumption that the additive rateconstant for a chemical group is only influenced byneighbouring functional groups did not allow a goodparameterization for the rate constants of organicnitrates. The use of a second parameter to alter thereactivity of C-H bonds in -position to thefunctional group resulted in markedly better agreementbetween calculated and measured rate constants, butwas not extended due to the limited set of data. This indicates that strong electron withdrawing groups(e.g., nitrate groups) might influence the reactivityof C-H bonds that are not directly adjacent.  相似文献   
955.
乡村治理是中国治理体系的底层与基座,产业融合发展是乡村振兴的核心,也是考量乡村治理绩效的重要方面。在现行的“乡政村治”治理模式下,政治能人替代传统乡贤成为新的乡村治理主体,探究其治理能力与产业融合发展之间的耦合关系及作用机制,对实现乡村振兴战略、构建“三治合一”的治理体系具有重大而深远的意义。本文在系统检视政治能人—产业融合发展耦合关系和作用机制框架的基础上,分别建构了政治能人治理能力、乡村产业融合发展的测评指标体系,以甘肃省金昌市139个行政村为评价单元,采用地理探测器模型,揭示了治理能力与产业融合发展的耦合关系及作用机制。研究表明:① 139个行政村中,“内生”型(En型)和“内生+嵌入”型(En-Em型)村庄分别占45.3%和54.7%,两类村庄中,内涵特征指标值差异较小,而外延指标值En-Em型村庄较En型村庄大;② 产业融合以中低水平为主,且En-Em型村庄产业融合的基础、广度和深度以及效果均好于En型村庄;③ 单因子探测显示两类村庄乡村产业融合受外延因子的影响较内涵因子大,且En-Em型村庄较En型村庄弱;双因子交互作用探测显示内涵因子在En型村庄中的作用较En-Em型村庄强,而外延因子相反,表明嵌入型政治能人治理能力对产业融合的作用较为显著。  相似文献   
956.
通过双面剪切试验对24个试件进行高延性纤维增强复合材料(PET FRP)与混凝土界面黏结性能研究,研究参数包括FRP种类、FRP黏结厚度、黏结长度和黏结宽度;分析各参数对PET FRP与混凝土黏结性能的影响,基于试验结果评估现有黏结滑移关系模型,并进行模型修正。研究结果表明,在有效黏结长度内,随着黏结长度的增加,PET FRP与混凝土界面黏结强度增大;当超过有效黏结长度后,增加PET FRP黏结长度不能明显增加界面黏结强度,但可提高试件破坏的延性;增加PET FRP黏结宽度可提高界面黏结强度,但会受PET FRP黏结宽度和混凝土宽度比值的影响;当界面刚度接近时,碳纤维增强复合材料(CFRP)与混凝土界面黏结强度远小于PET FRP与混凝土界面黏结强度。  相似文献   
957.
We derive the current-voltage relationship in the auroral region taking into account magnetospheric electrons for the bi-Maxwellian and kappa source plasma distribution functions. The current-voltage formulas have in principle been well known for a long time, but the kappa energy flux formulas have not appeared in the literature before. We give a unified treatment of the bi-Maxwellian and kappa distributions, correcting some errors in previous work. We give both exact results and two kinds of approximate formulas for the current density and the energy flux. The first approximation is almost generally valid and is practical to compute. The first approximation formulas are therefore suitable for use in simulations. In the second approximation we assume in addition that the thermal energy is small compared to the potential drop. This yields even simpler linear formulas which are suitable for many types of event studies and which have a more transparent physical interpretation than the first approximation formulas. We also show how it is possible to derive the first approximation formulas even for those distributions for which the exact results can not be computed analytically. The kappa field-aligned conductance value turns out always to be smaller than the corresponding Maxwellian conductance. We also verify that the obtained kappa current density and energy flux formulas go to Maxwellian results when k .  相似文献   
958.
2017年7月23日吉林宁江M 4.9地震前,地震影响范围内电磁台站出现多种电磁异常,其中4项电磁手段异常明显,分别是:地磁垂直分量日变幅加卸载响应比异常、地磁场总场强度F21每日一值空间相关异常、绥化地震台地电阻率EW向反向下降异常及林甸电阻率EW向整点值变化异常簇异常。本文对地磁异常进行统计、分析,为东北地区未来利用电磁方法分析预测地震提供经验。  相似文献   
959.
Root-mean-square distance Drms with characteristic of weighted-average is introduced in this article firstly. Drms can be used to capture the general proximity of a site to a dipping fault plane comparing with the rupture distance Drup and the seismogenic distance Dseis. Then, using Drup, Dseis and Drms, the hanging wall/footwall effects on the peak ground acceleration (PGA) during the 1999 Chi-Chi earthquake are evaluated by regression analysis. The logarithm residual shows that the PGA on hanging wall is much greater than that on footwall at the same Drup or Dseis when the Drup or Dseis is used as site-to-source distance measure. In contrast, there is no significant difference between the PGA on hanging wall and that on footwall at the same Drms when Drms is used. This result confirms that the hanging wall/footwall effect is mainly a geometric effect caused by the asymmetry of dipping fault. Therefore, the hanging wall/footwall effect on the near-fault ground motions can be ignored in the future attenuation analysis if the root-mean-square distance Drms is used as the site-to-source distance measure.  相似文献   
960.
网络文本中所包含的相关信息目前已成为公共安全事件紧急救援与影响评估的重要信息源。现有的方法虽然可定向地提取文本信息中事件的各类要素信息,但由于缺乏面向事件的整体建模与解析框架,难以从网络文本中获取系统的事件要素的结构化信息,即所提取的事件要素信息要么不够完整,要么与目标事件不匹配,由此产生的遗漏与谬误难以支撑针对公共安全事件信息的系统分析。为解决该问题,本文提出了面向公共安全事件的网络文本大数据结构化理论框架,首先,建立了公共安全事件的语义框架,并以地震事件为例构建了相应的结构化表结构;其次,应用训练语料的关联标注解决了事件要素与事件无法匹配的难点;最后,通过使用可融合关联信息的文本解析算法,系统提取了事件类型、事件名称、事件时间、事件位置及其他属性,基本实现了网络文本中不同事件信息的结构化。本文以云南邵通鲁甸地震为例,展示了地震事件的网络文本信息的结构化过程与结果,为分析地震所受的关注程度以及救援状况提供了重要参考。在上述研究的基础上,开发了面向公共安全事件的网络文本信息挖掘系统,展示了地震事件文本的结构化解析以及由此实施的事件关注度分析。  相似文献   
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