基于三方确认的船员服务资历管理模式

为破解当前服务资历监管难题,文中在梳理关于船员服务资历管理相关法规要求的基础上,针对当前监管中存在的问题,提出了基于三方确认的船员服务资历管理模式。该管理模式充分利用当前信息科学技术,有助于促进船长、公司和海事管理机构三方有效履行职责,更大程度地保证服务资历的真实性。     

海域围堰复杂地质深基坑支护的变形规律分析

为有效控制上软下硬地质条件下海域围堰围护结构的变形,以汕头苏埃通道工程始发井及后配套基坑为依托,对基坑施工中围护结构水平位移、混凝土支撑轴力、地面沉降等项目进行全过程监测,分析围护体系的变形受力与开挖工序的对应关系。主要研究与结论如下： 1）围护结构的最大水平位移的发生位置随基坑开挖深度增加逐渐下移,围护结构水平位移与支撑轴力最大值都位于基坑中下部位置,且二者都表现了基坑西侧大于基坑东侧; 2）基坑周边未加固段地表持续沉降,加固段的地表沉降较小; 3）建立综合监测预警机制,对基坑施工薄弱部位提出预警,信息化指导施工,保证了基坑的施工安全,为后续类似地质条件下基坑支撑体系提出了优化建议。     

富水卵漂石地层盾构滚刀磨损规律及寿命预测分析

为探究成都富水卵漂石地层盾构滚刀磨损规律及寿命特性,以成都地铁17号线凤温区间和明一区间第1次查换刀情况为研究对象,首先对两区间不同开口率刀盘的滚刀磨损形式和磨耗系数进行对比,之后采用基于现场实测数据的滚刀寿命预测模型对查换刀距离进行预测,最后通过第2次换刀对预测效果进行验证。研究结果表明： 1)富水卵漂石地层滚刀磨损形式主要表现为尖状磨损和偏磨磨损,偏磨滚刀主要分布于刀盘边缘及中心区域; 2)滚刀磨耗系数与安装位置半径关系曲线大致呈U形分布,中心滚刀和边缘滚刀的磨耗系数较大,正面滚刀的磨耗系数较小; 3)刀盘开口率是影响滚刀磨耗系数和偏磨概率的重要因素。     

论黄金分割定律及其在高速公路机电工程中的应用

黄金分割比例无所不在,它造就了一切事物的和谐美,可以应用在艺术、绘画、工程设计等各个方面.在高速公路机电工程的设计和施工中,除了应满足功能上的要求外,考虑黄金分割定律的应用,可以收到意想不到的效果.根据实际情况,黄金分割比例的应用范围可以在0.5～0.75之间.另外,正确利用视错觉,对于视觉效果和实际的使用,都是有很大益处的.     

Calibration of nonlinear car-following laws for traffic oscillation prediction

Frequency-domain analysis has been successfully used to (i) predict the amplification of traffic oscillations along a platoon of vehicles with nonlinear car-following laws and (ii) measure traffic oscillation properties (e.g., periodicity, magnitude) from field data. This paper proposes a new method to calibrate nonlinear car-following laws based on real-world vehicle trajectories, such that oscillation prediction (based on the calibrated car-following laws) and measurement from the same data can be compared and validated. This calibration method, for the first time, takes into account not only the driver’s car-following behavior but also the vehicle trajectory’s time-domain (e.g., location, speed) and frequency-domain properties (e.g., peak oscillation amplitude). We use Newell’s car-following model (1961) as an example and calibrate its parameters based on a penalty-based maximum likelihood estimation procedure. A series of experiments using Next Generation Simulation (NGSIM) data are conducted to illustrate the applicability and performance of the proposed approach. Results show that the calibrated car-following models are able to simultaneously reproduce observed driver behavior, time-domain trajectories, and oscillation propagation along the platoon with reasonable accuracy.     

我国航海类毕业生在船服务期缩短原因初探及对策研究

对于近几年开始出现的我国航海类毕业生在船服务期缩短这一现象,本文试图通过综合分析,探究其成因;并在此基础上,运用现代人力资源管理的有关观点,研究解决这个问题的方法.     

航海高等院校大学生心理服务体系的构建

航海高等院校心理健康教育全员意识不强,行业特殊性不强,工作模式单一,心理服务体系尚未构建完善,构建航海高等院校心理服务体系应系统化、国际化与本土化、科技化、行业化和人本化.     

On the regimes of underwater explosion for a submerged slender structure by pulsating bubble

Three regimes: near-, middle- and far-fields of underwater explosion are proposed in this study aiming at providing an overview on the responses of submerged slender structure by pulsating bubble. In the near-field, the material starts to yield, thus leading to structure breakdown immediately; remarkable structural global elastic deformation occurs in the middle-field as well as substantial movement; and a structure moves as a rigid body with negligible deformation for the far-field. Equivalent dimensionless parameters are obtained by two different dimensional analysis methods, among which a dominant similarity parameter is found out. Thus, a scaling law providing us with a relation between structural global response and the dominant similarity parameter is yielded, which can be used for demarcating the three regimes quantitatively. To demonstrate, three models corresponding to typical submarine parameters are performed in the case studies. Quantitative criterion of the three regimes is presented along with the regime diagrams. The structural global response features such as the deformation and maximal acceleration/speed of different regimes are provided as well.     

A universal distribution law of network detour ratios

Using trajectory data of normal taxis and ride-sourcing vehicles for 10 cities with various sizes in China, we analyze trip distance characteristics by examining the distribution of network detour ratios. The detour ratio for a specific ride is the ratio of the actual driving distance to the corresponding Euclidean (straight-line) distance. We find that, in spite of their different sizes and geographical features, the various cities exhibit an amazingly similar distribution law of network detour ratios: the mean of the detour ratios is inversely proportional to the Euclidean distance with an intercept. We further verify our findings with extensive simulation experiments for a hypothetical circular city with a directional grid street network. Our finding of this universal distribution law of network detour ratios contrasts sharply with the traditional wisdom of modeling throughout the past 50 years that have typically assumed a constant road detour ratio or factor within the range of 1.25–1.41. Our finding in the urban context also has far-reaching implications for fundamental research in many fields such as human mobility, human geography, facility location problems, logistic distribution networks and urban transportation planning.     

铁磁屏蔽体感应磁场随尺寸的变化规律

铁磁屏蔽体常用来屏蔽干扰磁场,内径一定情况下,屏蔽厚度越大,屏蔽效果越好,但造成感应磁场增大。弱磁场作用下,铁磁物体磁矩与外磁场成正比。以椭球体为例,计算了地磁场作用下,铁磁屏蔽体产生的磁矩,并分析了不同尺寸铁磁屏蔽体在测量点处的感应磁场变化规律。