中国好声音唱响海事界

1973年3月1日,中国正式恢复国际海事组织合法席位,成为国际海事大家庭的重要成员.40年的风雨洗礼,伴随中国航运、造船业的崛起,以及航运强国、造船强国建设的加快推进,中国好声音亦在全世界响起.     

级联系统变换器阻抗分析与稳定性改善方法研究

在级联系统稳定性判据基础上,分析级联系统前后级模块的阻抗比关系,讨论了LC滤波电路对后级负载输入阻抗的影响及其对级联系统稳定性的改善作用,介绍了电流源扰动注入法测试级联系统稳定性的方法,通过实验验证LC滤波电路对级联稳定性的改善作用.     

基于AR模型的填方路基沉降检评方法

通过运用数理理论之AR模型,开展填方路基沉降的检评工作,完成了工后质量评定任务,并预测其未来的沉降程度及趋势.研究表明:应用数理理论方法得出的结论,不仅具有实用价值和增强了可靠性,而且兼有鲜明的主动、事前的特征.     

平行导线磁场对点阵式霍尔电流传感器测量准确度的影响分析

针对研制的点阵式霍尔电流传感器工程应用中的抗干扰能力及安装要求问题,基于点阵式霍尔电流传感器模型和应用环境,建立平行导线磁场对霍尔电流传感器测量准确度影响的计算模型,提出该情况下传感器测量准确度的计算方法,发现传感器测量准确度与点阵个数、点阵半径、干扰源电缆与被测电缆的距离、干扰源电流与被测电流之比值大小有关。理论计算和实验结果都显示了算法的正确性和实用性,该算法对传感器的设计及安装具有指导意义。     

隧拱变形分析的自回归与分段回归方法应用

土建工程变形分析与预测,有赖于数理统计理论方法的支持。应用自回归理论和分段回归两种理论方法,实施隧拱沉降监控,结果表明:自回归理论宜于进行工程安全质量预测预报时使用,而分段回归方法能够准确、即时诠释监测对象的变形规律的变化,同样具备实用意义。     

Assessing the effects of stochastic perception error under travel time variability

Perceived mean-excess travel time is a new risk-averse route choice criterion recently proposed to simultaneously consider both stochastic perception error and travel time variability when making route choice decisions under uncertainty. The stochastic perception error is conditionally dependent on the actual travel time distribution, which is different from the deterministic perception error used in the traditional logit model. In this paper, we investigate the effects of stochastic perception error at three levels: (1) individual perceived travel time distribution and its connection to the classification by types of travelers and trip purposes, (2) route choice decisions (in terms of equilibrium flows and perceived mean-excess travel times), and (3) network performance measure (in terms of the total travel time distribution and its statistics). In all three levels, a curve fitting method is adopted to estimate the whole distribution of interest. Numerical examples are also provided to illustrate and visualize the above analyses. The graphical illustrations allow for intuitive interpretation of the effects of stochastic perception error at different levels. The analysis results could enhance the understanding of route choice behaviors under both (subjective) stochastic perception error and (objective) travel time uncertainty. Some suggestions are also provided for behavior data collection and behavioral modeling.     

南京市公交企业补贴机制研究与分析

城市公共交通经营亏损是一个不争的事实,研究公共交通合理补贴是一个迫切需要解决的问题。本文在对公共交通经营方式分析的基础上,结合南京公交集团经营情况分析,提出以成本补偿为依据,改进完善公交补贴机制,合理确定补贴额,拓宽对公交政策性亏损的补贴来源渠道。同时,借鉴台北市对公共交通的经济补贴政策及相关的评价制度,将行风评议结果纳入考核指标体系。呼吁政府在加大资金补贴的基础上,进一步落实公交优先政策,从政策、规划等方面予以支持,改善公交企业的经营环境,推动公共交通事业的平稳健康发展。     

Multi-objective bilevel construction material transportation scheduling in large-scale construction projects under a fuzzy random environment

Abstract

This paper investigates a transportation scheduling problem in large-scale construction projects under a fuzzy random environment. The problem is formulated as a fuzzy, random multi-objective bilevel optimization model where the construction company decides the transportation quantities from every source to every destination according to the criterion of minimizing total transportation cost and transportation time on the upper level, while the transportation agencies choose their transportation routes such that the total travel cost is minimized on the lower level. Specifically, we model both travel time and travel cost as triangular fuzzy random variables. Then the multi-objective bilevel adaptive particle swarm optimization algorithm is proposed to solve the model. Finally, a case study of transportation scheduling for the Shuibuya Hydropower Project in China is used as a real world example to demonstrate the practicality and efficiency of the optimization model and algorithm.     

高温双层海底管道轴向力计算方法

海底管道的轴向力分析是海底管道设计研究工作的一项重要内容。基于剪滞理论,提出了一套高温状态下双层海底管道轴向力计算的新方法。此方法可以很好地得出双层海底管道的轴向力分布状态以及内管和外管的最大轴向力。分析得到:内管的轴向力呈均匀分布;外管中间的固定段部分所受的轴向力呈均匀分布,其他部分轴向力呈线性增加,在管道的两端,轴向力达到最大值。     

隧道岩溶病害危险性分区在超前地质预报中的应用

针对厦蓉高速公路沙井街隧道岩溶的发育特点,提出了“隧道岩溶病害危险性分区”概念,并应用于超前地质预报工作中;根据中导洞开挖揭露的地质条件,对隧道岩溶病害危险性分区进行了修正,以指导主洞的超前预报工作,从而提高了预报工作的针对性并突出了重点;同时,基于高密度电法对不同介质电阻率的敏感性,在预报方法上将地表高密度电法与洞内地质雷达法相结合,提高了对重大岩溶病害预报的准确性.实际开挖结果显示:超前地质预报结果与实际情况高度吻合.