干扰井群水位预测在基坑降水中的应用

介绍了干扰井群工作后基坑的稳定和不稳定水位降深的计算方法,并编制了相应的计算程序。经过工程实践及现场监测,表明采用该方法进行基坑降水方案优化和设计明显优于规范提供的设计方法,同时具有一定的工程价值。     

膜结构成套技术研究

针对薄膜结构设计计算的整个过程,进行了理论方法的研究,并编制了相应的计算设计程序。算例表明了本文所述的理论方法以及程序的正确性及广泛适用性     

平面交叉梁板系统弹性自由振动

本文针对较常见的平面交叉梁板系统,设计了计算程序,计算弹性自由振动的频率及相应振型,供设计分析用.     

复合型土钉墙稳定性分析程序的编制及分析

复合型土钉墙的稳定性计算,就是不断地寻找最危险滑裂并修正设计参数过程,本文根据复合型土钉的工作原理编制了相应的计算程序,及如何确定设计参数以达到最佳设计效果。     

薄膜结构的初始形态设计分析

本文详细介绍了薄膜结构设计计算中的关键及难点问题——初始形态设计的理论方法,并编制了相应的有限元计算程序对薄膜结构的初始形态进行了分析。大量的算例和工程实例分析验证了本文所述理论方法及程序的正确性和广泛适用性。     

GPS与Galileo双系统组合精密单点定位性能分析

伽利略卫星导航系统是由欧盟和欧洲航天局联合打造的全球卫星导航系统。本文提出了一种基于GPS/Galileo双系统伪距、载波相位观测量的精密单点定位模型,利用MGEX数据网提供的实测数据对双系统动态、静态PPP进行了解算分析并且分别与单一GPS或Galileo系统解算结果进行对比分析。结果显示,双系统组合定位能力远优于任一单系统;双系统动态PPP定位精度可达厘米级,同时定位收敛时间也更快;双系统组合静态PPP的定位精度在1~3cm量级,静态PPP的定位精度优于相应数据动态PPP的定位精度;双GNSS系统组合对城市遮挡环境下的定位导航具有重要意义。     

基于ANSYS的剪力墙等效刚度计算

利用商用程序ANSYS计算不同横向荷载作用下剪力墙顶点位移,从而根据设计需求计算相应荷载工况下剪力墙等效刚度,为规则和非规则开洞剪力墙的等效刚度的计算提供了一种新途径。     

工程机械管路的计算机辅助设计

在工程机械的管路系统设计中应用ＣＡＤ技术，采用矢量代数理论，建立了产品的设计模型，编制了相应的计算程序。文中还列举了设计实例。     

深基坑支护结构内力与变形时空效应分析的程序实现

提出了深基坑支护结构内力与变形时空效应分析的三维有限元模型。以此为基础 ,介绍了相应的计算程序TSEF的实现过程 ,提出了土压力的修正方法 ,给出了主程序计算框图及荷载向量计算子程序框图 ,说明了程序的功能和特点。通过检验和算例分析 ,验证了程序的正确性。该程序可模拟基坑分步开挖过程、支撑方式的变化、地基的流变效应 ,可以计算挡墙上任意时刻、任意位置的内力与变形 ;可为深基坑支护、开挖设计及施工参数的选取提供依据     

薄膜结构的数值分析理论研究

本文对薄膜结构的数值分析理论进行了研究,系统地给出了求解薄膜结构问题的数值方法;详细地介绍了薄膜结构设计计算中的关键问题--初始形态设计分析和风振响应分析,并编制了相应的有限元计算程序;最后给出的数值算例验证了本文所述数值分析理论及程序的正确性和广泛适用性.     

水平梯度和映射函数对PPP对流层延迟估计的影响分析

基于GPS精密单点定位(PPP)技术,比较分析了水平梯度及目前三种主要的映射函数(NMF,VMF1和GMF)对天顶对流层延迟(ZTD)估计精度的影响.研究结果表明,在气象变化剧烈和低高度截止角情况下,附加水平梯度的对流层延迟模型有利于提高ZTD精度;就映射函数效用而言,VMF1和GMF较NMF更优.     

基于精密单点定位模型的组合GPS／GLONASS系统的可靠性分析

给出了评价组合GPS／GLONASS系统可靠性的方法,在此基础上,利用IGS跟踪站的实测数据分别从多余观测分量、定位精度因子和可靠性指标三个方面对GPS／GLONASS精密单点定位系统的可靠性进行了分析,并同GPS单系统进行对比,结果表明,组合GPS／GLONASS精密单点定位系统的可靠性及定位精度均优于GPS系统。     

PPP技术在水深测量成果质量检验中的可行性研究

传统的水深测量方法已不能满足当今水深测量精度要求,随着PPP技术的不断发展,其动态定位精度已可以达到厘米级,而且作业模式灵活高效。本文主要探讨了利用PPP技术进行水深测量的基本原理和作业步骤,从多个方面分析了其精度及可靠性,给出了相应的作业要求,并讨论了其用于水深测量成果质量检测的优点。     

基于GPS和BDS组合精密单点定位精度分析

北斗定位导航系统(BDS)于2012年底开始向亚太大部分地区正式提供连续无源定位、导航、授时等服务。本文简要介绍GPS和BDS精密单点定位(PPP)的原理,给出了无电离层组合模型及Kalman滤波模型,并利用实测的GPS和BDS静态与动态观测数据进行精密单点定位实验。实验改正了对流层延迟影响、相对论效应、地球自转、多路径影响和观测噪声等误差,比较了GPS、BDS和二者组合定位的实验结果。实验结果表明:通常情况GPS平均可视卫星颗数多于BDS系统,但在特殊情况下,BDS卫星颗数多于GPS;BDS卫星星座分布良好,系统性能稳定,静态PPP收敛后精度达到9.89 cm,动态PPP精度能达到分米级,且运动轨迹和动态GPS定位轨迹整体一致,达到BDS设计要求;GPS和BDS组合定位的精度最优,静态实验精度处于1 cm~2 cm,动态实验精度优于10 cm。     

GPS精密单点定位在城市工程测量中的应用

简单介绍了利用BERNESE5．0软件精密单点定位的计算流程,分析了IGS目前提供的各种精密星历的精度和时延性,根据实验数据进一步比较了超快速星历和最终星历对精密单点定位精度的影响。结果表明,利用IGS的超快星历也可以达到厘米级定位精度,从而为城市静态GPS控制网和网络RTK测量提供了有益的补充。     

基于平衡记分卡的轨道交通PPP项目绩效评价体系研究

从我国轨道交通PPP项目绩效评价体系缺失的现状出发,借鉴平衡记分卡四维的理念,在分析轨道交通PPP项目特性的基础上,构建了轨道交通PPP项目的六维绩效评价体系。以灰色关联度分析法确定指标权重,然后选择白化权函数灰评估法确定指标的聚类系数,以聚类系数评价轨道交通PPP项目的绩效。最后,以徐州市轨道交通1号线PPP项目为对象进行实证分析。     

Ownership structure and the technical,cost, and revenue efficiency of Italian airports

This paper investigates the role of the different ownership types of operators in the Italian airport sector. A meta-frontier conceptualization is utilized to consider ownership heterogeneity and compare airport efficiencies. Efficiencies are measured from multiple perspectives. Cluster analysis is adopted to uncover airport configurations with respect to inefficiencies. The results suggest that ownership heterogeneity may exert substantial influence on airport efficiency. However, while PPP airports have greater technical efficiency than airports operated by publicly owned operators, the meta-frontier analysis relative to cost and revenue efficiency does not provide evidence that PPP airports perform better. Indeed, publicly managed airports achieve comparable or better performance in terms of revenue efficiency. Findings also indicate that ownership is not the only factor affecting airport performance.     

PPP模式在中国的研究发展与趋势

PPP(Public Private Partnership)模式在中国基础设施、公用事业等领域的投资与建设发挥越来越重要的作用,有必要对其相关领域的研究进行梳理以更好地指导实践。通过两阶段法分析PPP在中国的研究发展与趋势:整理国家自然科学基金自成立以来所有支持PPP相关研究的项目,对项目的年度数量、支持金额、研究范围等进行时序分析,将PPP在中国的发展划分为3个阶段并总结各阶段的特点;通过整理各基金项目负责人及申请单位信息,以及代表PPP在中国研究趋势的论文,建立并采用P-P-P(Project-Partnership-Process)维度分类法将研究内容从3个维度进行了研究趋势的总结与分析,为PPP模式在中国今后的研究与实践提供一定参考。     

PPP 项目再谈判关键风险因素识别与操作规程设计

为更有效地提供基础设施与公共服务,PPP 项目在我国开始大力推广。但由于 PPP 合同的不完善性以及长特许期内的不可预测风险,PPP 项目再谈判在实施过程中极易发生。为了减少不必要的再谈判,避免 PPP 再谈判带来的管理效率降低、公共资源浪费等问题,识别了 PPP 项目再谈判关键风险因素,并基于中国的实情与国际经验,设计了 PPP 项目再谈判的操作规程,包括发起预审机制、再谈判流程、监管机制等。邀请具有 PPP 项目管理实践经验的政府管理人员、私人投资者、咨询公司与学者,对设计的操作规程进行验证。该谈判操作规程能为政府提供借鉴,以促进 PPP 健康有序的发展。     

Developing a risk assessment model for PPP projects in China — A fuzzy synthetic evaluation approach

Earlier research works on PPP showed that an objective, reliable, and practical risk assessment model for PPP projects is essential to the successful implementation of PPP projects. However, actual empirical research studies in this research area are rather limited. This paper reports the second stage of a funded research study, which aims to develop a fuzzy synthetic evaluation model for assessing the risk level of a particular critical risk group (CRG) and the overall risk level associated with PPP projects in China. At the first research stage, thirty-four risk factors were identified through a comprehensive literature review and 3 new risk factors were proposed during a two-round Delphi questionnaire survey. The most critical 17 risk factors were selected through the calculation of normalized values. The correlation of these 17 critical risk factors (CRFs) was further analyzed via factor analysis and 6 CRGs were formulated, namely: (1) Macroeconomic Risk; (2) Construction and Operation Risk; (3) Government Maturity Risk; (4) Market Environment Risk; (5) Economic Viability Risk; and (6) Government Intervention. On the basis of the research works conducted at the first research stage, the weightings for each of the 17 critical risk factors (CRFs) and 6 CRGs were determined through the two-round Delphi questionnaire survey. A set of knowledge-based fuzzy inference rules was then established to set up the membership function for the 17 CRFs and 6 CRGs. The empirical research findings showed that the overall risk level of PPP highway projects is between “moderate risk” and “high risk”. Hence it could be construed that investment in PPP highway projects in China may be considered as risky. In fact, the Delphi survey respondents perceived that “Government Intervention” is the most CRG; with “Government Maturity Risk” being the second; “Economic Viability Risk” the third; “Market Environment Risk” the fourth; “Construction and Operation Risk” the fifth; and “Macroeconomic Risk” the last. These findings revealed that government intervention and corruption may be the major hurdles to the success of PPP highway projects in China. These may be caused by inadequate law and supervision system and poor public decision-making process. Although the fuzzy synthetic evaluation model was primarily developed for PPP projects in general, the research method could be replicated in a specific type of PPP project, such as water treatment projects and hospital projects, to produce similar models for inter-type comparisons. By doing so, it provides an opportunity for practitioners to assess the risk level of different types of PPP projects based on objective evidence rather than subjective judgment. The most CRG for different types of PPP projects could be identified and both precautionary and remedial actions could be taken as soon as possible. Such an extension would provide a deeper understanding of managing different types of PPP projects.