Effects of apparent image velocity and complexity on the dynamic visual field using a high-speed train driving simulator

Train driving is a highly visual task. The visual capabilities of the train driver affects driving safety and driving performance. Understanding the effects of train speed and background image complexity on the visual behavior of the high-speed train driver is essential for optimizing performance and safety. This study investigated the role of the apparent image velocity and complexity on the dynamic visual field of drivers. Participants in a repeated-measures experiment drove a train at nine different speeds in a state-of-the-art high-speed train simulator. Eye movement analysis indicated that the effect of image velocity on the dynamic visual field of high-speed train driver was significant while image complexity had no effect on it. The fixation range was increasingly concentrated on the middle of the track as the speed increased, meanwhile there was a logarithmic decline in fixation range for areas surrounding the track. The extent of the visual search field decreased gradually, both vertically and horizontally, as the speed of train increased, and the rate of decrease was more rapid in the vertical direction. A model is proposed that predicts the extent of this tunnel vision phenomenon as a function of the train speed.Relevance to industryThis finding can be used as a basis for the design of high-speed railway system and as a foundation for improving the operational procedures of high-speed train driver for safety.     

Strength and dilatancy behaviors of deep sands in Shanghai with a focus on grain size and shape effect

With rapid development of infrastructures like tunnels and open excavations in Shanghai, investigations on deeper soils have become critically important. Most of the existing laboratory works were focused on the clayey strata up to Layer 6 in Shanghai, i.e. at depth of up to 40 m. In this paper, Layers 7, 9, and 11, which were mostly formed of sandy soils at depth of up to 150 m, were experimentally investigated with respect to physico-mechanical behaviors. The stress–strain behaviors were analyzed by the consolidated drained/undrained (CD/CU) triaxial tests under monotonic loading. One-dimensional (1D) oedometer tests were performed to investigate the consolidation properties of the sandy soils. Specimens were prepared at three different relative densities for each layer. Also, the micro-images and particle size analyzers were used to analyze the shape and size of the sand grains. The influences of grain size, density, and angularity on the stress–strain behaviors and compressibility were also studied. Compared to the other layers, Layer 11 had the smallest mean grain size (D₅₀), highest compressibility, and lowest shear strength. In contrast, Layer 9 had the largest mean grain size, lowest compressibility, and highest shear strength. Layer 7 was of intermediate mean grain size, exhibiting more compressibility and less shear strength than that of Layer 9. Also, the critical state parameters and maximum dilatancy rate of different layers were discussed.     

基于人工神经网络的水洞试验装置的PID自动控制系统

在水洞试验中，通过水泵及收缩段的形状控制水洞的运行过程，以保证水洞的稳定运行，并保证所进行的各种试验的质量。PID调节是最常见的一种。文章给出了一种基于人工神经网络实现自学习PID控制方法。利用该方法可以较好地实现水洞的控制。     

新产品——钢带增强聚乙烯螺旋波纹管

钢带增强聚乙烯螺旋波纹管是一种创新的埋地排水管,把钢材的高刚度、高强度和聚乙烯的柔韧、耐腐结合在一起,突出的优点是环刚度高和节约原材料.     

历史中心区复兴中的地域性问题与对策

本文以上海思南路47～48街坊改造为例,探讨城市形态更新与居民外迁问题,并期待相关地域性社会对策的出现。     

虚拟专用网的体系结构及实现

提出VPN接入设备的体系结构 ,包括系统的应用模型、层次划分和内部详细结构 ,阐述实现VPN的关键技术。     

为了满足使用者需求而设计——上海地铁研究·使用者需求

在上海地铁研究中,我们发现了许多使用者的不满。这些不满来自于设计师对使用者的缺乏了解和缺乏关注。通过对上海地铁真实的使用者、真实的地点和真实的时间的调研,我们分析出25项上海地铁使用者的需求。并提出希望设计师能够从这些使用者的需求出发,去作为使用者带来良好体验的设计。     

环件轧制中晶粒变化的计算机模拟

金属微观结构变化影响产品机械性能。本文将金属再结晶数学模型与三维热刚塑性有限元结合起来进行模拟计算，获得了环件轧制中晶粒变化的三维分布规律，及与以往不同的轧制力和力矩变化。所用方法有普遍适用性。     

不锈钢绕带容器环板与绕带端头的焊接

本文通过焊接试验对奥氏体不锈钢绕带容器环板与绕带焊接工艺进行了研究分析,并得出了合理的焊接方法和工艺参数。     

万家寨引黄工程有压输水隧洞裂缝及处理

文中论述了万家寨引黄工程南干一级，二级泵站出水洞混凝土裂缝出现情况。裂缝出现原因分析及缺陷处理方法。