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851.
本文运用可靠性理论,通过可控性数值和未被发现的粗差对平差未知数影响的向量长度,分析了重力网的可靠性。根据优化设计原理,建立了重力网观测精度与经费的关系式。讨论了在一定经费范围内的重力网二类优化问题,认为在一定经费指标下,可以通过改善观测方案来加强网的可靠性。最后应用本文的方法对沂沭带中、北段的安丘重力网进行了实例计算。 相似文献
852.
Pathways to seismic hazard evaluation: Extreme and characteristic earthquakes in areas of low and high seismicity 总被引:4,自引:0,他引:4
Paul W. Burton 《Natural Hazards》1990,3(3):275-291
The general philosophy of seismic hazard evaluation described here is appropriate for selection of seismic input to regional earthquake engineering codes prior to detailed on-site inspections and geotechnical assessments. Some probabilistic seismic hazard methodologies which can be applied in areas of low and high seismicity, are briefly described to emphasise the main equations with specimen results. Three aspects of hazard assessment are explored by different pathways. These include the analysis of regional earthquake catalogues to obtain magnitude recurrence, particularly using Gumbel extreme value statistics. This is extended to assess ground shaking hazard which is usually sought by earthquake engineers. Thirdly, the concept of earthquake perceptibility is developed, leading to the identification of an earthquake magnitude or type which is characteristic of a region. This most perceptible earthquake is most likely to be felt at any site in a region and provides an earthquake selection criterion which can be used in aseismic design of noncritical structures. Because there are several methods of seismic hazard evaluation, the view is expressed that it is sensible for practical purposes to seek results from different methods or different pathways to the hazard evaluation.Paper presented at the Commission of the European Communities' School on Earthquake Hazard Evaluation, Athens, and at the 21st General Assembly of the European Seismological Commission, held in Sofia, 1988.Now at School of Environmental Sciences, University of East Anglia, University Plain, Norwich NR4 7TJ, U.K. 相似文献
853.
通过实地调查上海、广州、武汉、乌鲁木齐4座城市的15座体育场馆,并在结合相关专家访谈的基础上,分析了大型体育场馆区域的产生、空间特征和功能布局,重点探讨了存在的主要问题,包括:场馆区域布局设计与区域条件不相适应,建筑设施之间的空间联系不足,区域整体空间局促,建筑设施的功能布局失调,交通流线布局设计有待改进,与外部空间环境缺乏紧密的联系。借鉴国外场馆区域布局设计经验,提出从多样性和整体性方面,合理规划场馆区域的功能布局;从开放和融合的视角,协调中心与周边区域的发展关系;以人性化和层次化手段,优化区域内的交通流线。 相似文献
854.
In this study, we used institutional analysis to investigate the design of innovative contracts for agri-environmental and climate schemes. The aim of such contracts is to better incentivize farmers for the provision of environmental public goods in comparison to current ‘mainstream’ contracts. For the analysis, we differentiated four contract types: result-based, collective, land tenure, and value chain contracts. To represent each type in the analysis, we selected 19 case examples from six European countries. Cases were identified through a mix of methods, combining literature review, web search, and expert consultation. After a structured data collection based on Ostrom’s institutional analysis and development (IAD) framework, we focused our analysis on the involved actors and their roles in contract governance. Our results highlight the great diversity of public, private, and civil actors involved from the local, regional, national or international governance level, each performing one or several critical roles in contract governance. We found that it is highly context-dependent which actors assume certain roles. We also discuss how provision of environmental public goods through the contracts might potentially be impacted by certain roles and their assignment to specific actors. 相似文献
855.
856.
Meissa Fall Auckpath Sawangsuriya Craig H. Benson Tuncer B. Edil Peter J. Bosscher 《Geotechnical and Geological Engineering》2008,26(1):13-35
Investigations on the mechanical behavior of compacted gravel lateritic soils have been the subject of several studies. Used
as road materials, soils tests were mainly performed using standard tests. Static loads as unconfined compression test (UCT)
remain the only engineering approach used. Alternative testing techniques can be chosen as supplementary tests for characterizing
pavement materials. These researches were conducted so as to determine the response of these particular and problematic soils
in its compacted form with road traffic loads. This paper presents the results of research conducted to investigate the effect
of the soil compacity on the resilient modulus of lateritic soils. The influence of the percentage of cement added so as to
stabilize each sample at the optimum modified proctor (OPM) State was also determined. Soil big specimens of around 180 mm
diameter (with length to diameter aspect ratio of 2:1) were prepared according to the standard procedure described by AASHTO
T 307 and then were subjected to repeated load triaxial tests. The models used, analyzed and developed in this paper are mainly
the Andrei and the Uzan–Witczak universal model. Test results showed that the specimen compacity has no significant influence
on the resilient modulus of the investigated gravel lateritic soils. Soil specimens with variation of the percentage of cement
added exhibited the highest resilient modulus values while the specimens with variation of the compacity exhibited the lowest
values. The resilient modulus variation seems to be independent of the level of stress. 相似文献
857.
858.
李珍 《测绘与空间地理信息》2017,(4)
针对现有地形图数据无损转换共享难、无法直接入库(Arc GIS)的问题,利用C#语言及VS2015开发环境,在AutoCAD2015平台下进行二次开发,设计出了一套面向直接入库的测量绘图系统。该系统采用ESRI公司的"CAD制图规范"中存放要素类的定义信息和要素的属性数据的组织规则,使得系统所绘图形不需要经过任何中间处理,就如同使用ArcGIS中的GeoDataBase地理数据库中的原生要素类和原生要素一样。测试结果表明,本系统较好地解决了上述问题,具有较高的应用价值。 相似文献
859.
空间数据库课程是地理信息系统专业的核心课程。本文针对该课程教学内容庞杂、概念和原理抽象、实践教学脱节等问题,从教学主线、理论教学、实践教学、课时安排、教学手段、教师选用等5个方面入手,对现有教学模式进行重新归整、优化与创新。从近3年的教学成效看,通过优化教学内容、强化教学实践、改进教学手段、提升教师技能等举措,提升了学生的兴趣,增强了学生发现、分析和解决问题的能力,取得了良好的教学效果。 相似文献
860.
针对不动产统一登记平台建设问题,该文以江西省,不动产登记平台建设为例从多源不动产登记信息数据的整合、不动产统一登记平台设计与实现两个方面开展。对土地、房产、草原、林地、海域等多行业的数据进行整理、整合,形成统一的不动产登记数据库。平台总体框架由基础保障系统、不动产历史数据库、共享服务平台、数据管理平台、政务基础平台、登记信息管理平台、登记信息公示平台7部分组成。 相似文献