Comparison between North-South Aid and South-South Cooperation: Based on the analysis of the new development finance institutions

According to the different players, development cooperation is often divided into North-South Aid and South-South Cooperation, both of which have a history of several decades. Since the beginning of the 21st century, the rise of a number of emerging economies has brought South-South Cooperation into a new stage, which can be seen from the establishment of some new development finance institutions led by developing countries. BRICS Bank, Asia Infrastructure Investment Bank (AIIB) and Silk Road Fund are three important new development finance institutions. Compared with the traditional development finance institutions like World Bank and International Monetary Fund (IMF), they have their own concepts of development cooperation, which are different from the traditional ones. First, the new finance institutions pay more attention to the equality between partners, not imposing conditions and respecting the ownership of development partners. Second, the new development finance institutions value the market philosophy, which means that they emphasize the importance of field investigation and implement development cooperation in accordance with the actual needs of the partners and the comparative advantages of the providers. Finally, the new development finance institutions focus their resources on problem-solving and avoid doctrines-imposing. They believe that it is easier for the developing countries to achieve development through a gradual and bottom-up model. Although there are differences between the traditional and new development finance institutions, the latter is not parallel to or substitute of the former. They can cooperate with each other and provide better public goods for international cooperation through inclusive competition.     

Efficient Dynamic Threshold Group Signature Scheme Based on Elliptic Curve Cryptosystem

The short secret key characteristic of elliptic curve cryptosystem （ECC） are integrated with the （ t, n ） threshold method to create a practical threshold group signature scheme characterized by simultaneous signing. The scheme not only meets the requirements of anonymity and traceability of group signature but also can withstand Tseng and Wang＇s conspiracy attack. It allows the group manager to add new members and delete old members according to actual application, while the system parameters have a little change. Cryptanalysis result shows that the scheme is efficient and secure.     

城市轨道交通建设工程声像档案归档业务探索

从服务于工程建设档案、适应新时代工程档案管理需要出发,成都市城市建设与自然资源档案馆组织相关专业力量,编写了成都市城市轨道交通建设工程全部子项的声像档案制作与归档要求。本文重点介绍了城市轨道交通建设工程声像档案归档类别及范围,供探讨思考,以促进建设工程声像档案接收范围的拓展和服务的提升。     

采用实测数据实时修正的机场跑道水膜厚度面域分布预估方法

为精准预估不同跑道状况与降雨条件下跑道水膜厚度的面域分布,基于二维浅水方程建立了水膜厚度面域分布数值模型,开发了基于格心型有限体积法和HLL(Harten, Lax and van Leer)格式近似Riemann解的数值求解算法;在此基础上,引入水膜厚度的实测数据,通过构造伴随方程,采用梯度下降法获取了实际降雨条件下的最优曼宁系数,从而动态修正了二维浅水方程的计算结果,精准预估了跑道水膜厚度面域分布;采用北京首都国际机场安全预警平台的水膜厚度实测数据和车载式LiDAR系统获取的路面高程数据,计算分析了曼宁系数更新间隔和高程空间采样间隔对模型求解效率和精度的影响,并采用实测数据验证了算法的准确性。研究结果表明：为满足水膜厚度实时监测需求,在综合考虑计算耗时与求解精度的条件下,曼宁系数的最优更新间隔为30～300 s,对于表面平整的道面,高程的最优空间采样间隔为0.1～0.5 m,对于存在车辙等病害的道面,高程的最优空间采样间隔为0.10～0.25 m;在真实降雨条件下,水膜厚度计算值与实测值的平均误差为0.13 mm,最大误差为0.76 mm,满足机场对水膜厚度的监测需求。由此可见,建...     

沥青混凝土路面裂缝处理技术研究

为规范沥青路面裂缝的处理程序,提高国内沥青混凝土路面的养护水平,在国内外调研的基础上,结合上海市沥青路面的特点,对裂缝的类型进行了详细的划分.针对活动裂缝和非活动裂缝,分别提出了对应的处理方法和处理构型.同时,给出了对应的裂缝处理材料选择方法,并系统提出了不同裂缝处理的工艺.提出的裂缝处理方法有助于养护技术的进一步规范化.     

为全路劳动安全卫生与环保事业作出突出贡献的二十年──祝贺《铁道劳动安全卫生与环保》杂志创刊二十周年

为全路劳动安全卫生与环保事业作出突出贡献的二十年──祝贺《铁道劳动安全卫生与环保》杂志创刊二十周年铁道部第一工程局中心卫生防疫站谭洪铁道部第四工程局中心卫生防疫站乐尚侃北京铁路局中心卫生防疫站李理哈尔滨铁路局齐齐哈尔中心卫生防疫站崔振国沈阳铁路局吉林...     

飞机轮迹横向分布测试系统的比选分析

文章介绍了国外机场相关轮迹横向分布测试系统,以及国内公路轮迹横向分布测试方法,通过分析各个测试系统的技术原理与系统自身的优缺点,并结合具体工程实例应用,综合考虑国内机场安全及运行管理要求,选取出一套最便捷、合适的机场跑道轮迹横向分布测试系统,为我国机场飞机轮迹横向分布数据收集提供参考。     

循环载荷下箱型梁极限强度性能实验研究

通过系列箱型梁模型实验,研究了箱型梁在极值循环弯曲载荷下的极限承载性能。分别对四个加筋箱型梁模型进行了循环载荷下的四点纯弯实验,实验分别采取单向及双向循环载荷两种施加方式。在单向循环弯曲实验中,模型的后续循环的极限强度与前一循环的后极限强度阶段的卸载点接近,但塑性变形有明显增加,极限承载能力下降显著;双向循环弯曲中,反向弯矩虽然抵消了部分塑性变形,但箱型梁的极限承载能力仍有明显下降。实验表明,实验加载过程中,箱型梁在承受极值循环载荷初期,其构件崩溃速率较缓,而一旦进入后极限阶段,崩溃速率显著加快;箱型梁在极值循环弯曲载荷下的极限承载性能,即后极限强度性能,相比一次性极限强度值逐步下降。     

VR技术在铁道车辆教学中的探索与应用

目前,我国铁路事业发展迅猛,铁道车辆专业的教学迎来了新的机遇和挑战.本文首先分析了铁道车辆专业的教学现状,随后分析了VR技术在铁道车辆专业教学中应用的优势和可能遇到的阻碍,肯定了VR技术对于教师教学和学生学习的积极作用.