Use of 3D compartment model for simplified full ship FE model. Part I: construction of FE model

Classification societies cannot cover the torsional strength assessment with simple empirical formula as the size of a containership increases drastically over 10 000 TEU in recent years. Torsional strength of a container ship is very difficult to estimate with an analytical method due to its alternatively varying cross sections, i. e. an open and a closed section. This article proposes an approach to construct a simplified FE model using a 3D compartment model available from the beginning of ship design process. The model is cut to pieces of lots of small pieces of lines by a set of transverse, longitudinal and horizontal planes. Two algorithms are developed for mesh generation of internal structures; one for assembling the broken lines into closed loops and the other for automatically generating mesh from the loops. Another algorithm is proposed to generate mesh for outer hull using outermost nodes of the FE model built for internal members. The validity of the simplified model is discussed along with a beam theory based approach in J Mar Sci Technol (2008)     

The public's understanding of the functionality and limitations of automatic braking in Japan

Automated driving systems are increasingly widespread in the automotive industry. To operate automobiles that are assisted by such systems, drivers must correctly understand their functionality and limitations. Hence, focusing on the rapidly spreading technology of automated braking, this study seeks to clarify the general public's understanding of automatic braking systems. A total of 210 Japanese people responded to a questionnaire regarding how automatic brakes are operated, how they work, when they disengage, and so on. The proportion of those who misunderstood the operation of the system is not especially high, but there were a certain percentage of people who had misconceptions; e.g., some believed that automatic braking could detect pedestrians or bicycles. Moreover, respondents were under the impression that drivers cannot readily disengage automatic braking systems. If they mistakenly use the automatic brake, there is a possibility of posing a risk to the road transportation system.     

楼宇三维路径模型的自动生成算法

提出了一种楼宇三维路径的自动生成算法.该算法首先使用图像细化算法及特征点提取算法建立单层楼的通道路径,并将房间等楼层实体作为结点连接到通道路径上,从而建立好单层楼的路径图;然后利用楼梯结点和电梯结点将相邻的楼层路径图相互连接起来,生成完整的楼宇三维路径模型.该路径模型是由弧和结点结构组成的带权图结构,可以应用于智能导航、楼宇自动控制、紧急情况的人员疏散及楼宇安全等领域.     

全电子自动复原道岔模块的研究

介绍一种全电子计算机联锁四线制道岔自动复原模块,来取代原来安全型继电器组成的道岔执行电路。全电子计算机联锁模块主要有微控制器MCU、可编程逻辑器件CPLD、道岔驱动电路、道岔表示电路、道岔检测电路和自动复原电路等组成。自动恢复电路包括驱动电路和继电器等组成。计算机联锁系统通过定位和反位检测单元检测电路中是否有表示电压,来决定微控制器MCU计时与否。道岔由定位转向反位或由反位转向定位时,若在规定的时间不能密贴,微控制器MCU发出继电器Js驱动指令,驱动继电器Js动作,通过继电器Js的接点,控制系统发出相反的转换指令,使道岔自动恢复到原来的位置。最后,提出了软件设计方案,用流程图对软件工作原理进行了说明。     

计轴自动站间闭塞电路方案探讨

根据TB／T2668—2004《铁路自动站间闭塞技术条件》所提出的要求，以奎北线、乌准线为例，介绍了计轴自动站间闭塞电路的构成和应用。     

TK-2DC软件前处理模块-贴体正交网格生成软件开发

贴体正交网格计算方法是通过坐标变换或坐标投影,把不规则物理区域进行离散以生成规则矩形计算区域的方法,所生成网格的疏密性和正交性对于保证数值计算精度至关重要。目前最常用的3种贴体正交网格计算方法是代数网格生成法、椭圆型方程网格生成法以及保角变换网格生成法。为了保证网格的正交性,简化网格计算量,所采用的贴体正交网格计算方法是上述3种方法的组合体,并且以该法为内核,开发了简单易学的贴体正交网格可视化计算软件,该软件可以与CAD进行无缝连接,大大缩短了数值模拟前期研究工作的时间。     

自动闭塞区段通过信号机布置方法探讨

通过对自动闭塞区段通过信号机布置一般方法在应用中遇到的问题的分析，提出相对应的解决办法，并对影响区间信号布点的各因素进行分析，探讨各因素的优先级，提出科学合理的区间通过信号机布置方法。     

ATP控车模式的DC模型与可靠性分析

列车控制是保障高速列车安全运行的关键技术.对国际上广泛应用的ATP控车模式建立了基于时段演算的模型,并通过对模型的推演,对ATP控车模式进行了初步的可靠性分析,为设计安全、可靠的ATP系统提供新的理论分析手段.     

基于扩张状态观测器的列车轨迹跟踪控制及其在CMC环境的测试

在列车运行过程中,存在着复杂且不确定的外部环境,很难获得阻力的表达式和阻力系数,因此,准确的外部阻力估计直接影响到列车轨迹跟踪精度。设计一种新型的基于扩张状态观测器的列车轨迹跟踪控制算法,将外部阻力和内部干扰扩展为一个新的状态变量,并进行精确估计。采用遗传算法对扩张状态观测器的参数进行优化。最后,在国产CMC芯片的硬件环境下进行测试。测试结果表明,基于扩张状态观测器的控制策略比现有广泛使用的PID算法具有更好的跟踪性能。得出以下结论:所设计控制算法通过补偿各种干扰的影响达到列车位置和速度的精确追踪,具有较强的抗干扰性。     

Computing 4D near-optimal trajectories for dynamic air traffic flow management with column generation and branch-and-price

Abstract

The current air traffic system faces recurrent saturation problems. Numerous studies are dedicated to this issue, including the present research on a new dynamic regulation filter holding frequent trajectory optimisations in a real-time sliding horizon loop process. We consider a trajectory optimisation problem arising in this context, where a feasible four-dimensional (4D) trajectory is to be built and assigned to each regulated flight to suppress sector overloads while minimising the cost of the chosen policy. We model this problem with a mixed integer linear programme and solve it with a branch-and-price approach. The pricing sub-problem looks for feasible trajectories in a dynamic three-dimensional (3D) network and is solved with a specific algorithm based on shortest path labelling algorithms and on dynamic programming. Each algorithm is tested on real-world data corresponding to a complete traffic day in the European air traffic system; experimental results, including computing times measurement, validate the solution process.