Simultaneous localization and mapping of autonomous underwater vehicle using looking forward sonar

A method of underwater simultaneous localization and mapping (SLAM) based on on-board looking forward sonar is proposed. The real-time data flow is obtained to form the underwater acoustic images and these images are pre-processed and positions of objects are extracted for SLAM. Extended Kalman filter (EKF) is selected as the kernel approach to enable the underwater vehicle to construct a feature map, and the EKF can locate the underwater vehicle through the map. In order to improve the association efficiency, a novel association method based on ant colony algorithm is introduced. Results obtained on simulation data and real acoustic vision data in tank are displayed and discussed. The proposed method maintains better association efficiency and reduces navigation error, and is effective and feasible.     

真空轻型井点降水在深埋隧道未成岩富水粉细砂层施工中的应用

真空轻型井点降水在基坑和浅埋隧道施工中应用较多,但很少在深埋隧道中应用,对其降水效果也难以判断。依托兰渝铁路桃树坪隧道洞内降水工程,通过降水管如何设计与施工对真空轻型井点在洞内降水进行了研究。实践证明轻型井点降水在深埋隧道能够达到无水施工的效果,保证了隧道开挖过程中的砂层自稳,并对后续施工提出了改进建议。对类似工程具有参考意义。     

一种基于布里渊光时域反射的土质隧道分布式光纤传感应用技术

为了开发一种高密度实时监测技术,用于及时了解隧道开挖面前方地层的变形情况,在分布式光纤监测技术的已有成果基础上,采用模型设计、室内试验与应用工艺验证的方法,研究开发一种用于土质隧道围岩超前位移监测的方法,得出监测力学模型与监测方程,提出传感器的制作与标定、布设与安装,系统集成与实时监测的工艺技术。研究成果在工程实践应用中得到了验证,取得了初步的应用效果。     

运输船的发展与展望

本文给出了散货船、多用途船、集装箱船、油船/化学品船及滚装船等主要类型运输船各自的技术特点、发展趋势以及随之而来的技术问题。     

城市交通指路标志的认知性心理学实验评价研究

提出了一种通过驾驶动态模拟心理学实验评价城市指路标志认知性的方法.针对3种不同形式的指路标志,建立了用于驾驶模拟实验的路网及相关的指路标志系统,设计了驾驶模拟对比心理学实验方案;选取42名受试者进行分组实验并统计分析结果.研究表明,驾驶模拟实验能够有效地反映出驾驶员在道路交通环境及动态驾驶条件下对指路标志的认知性.通过对给定路线及目标的完整到达、非完整到达和未能到达3种实验结果及相关行驶路段的统计分析,得出了3种方案认知有效性的排序;最后对3种方案的设计及应用进行了说明.     

山区高墩梁桥方案的经济性比较

通过对在V形山谷修建40m、50mT梁桥及120m连续刚构桥方案进行比较,从结构合理性及经济性方面对山区修建高墩连续T梁桥提出一些观点,并分析了它们的上下部结构造价,得出修建高墩连续T梁桥的最优条件。     

基于FPGA的UART16550的设计与实现

在FPGA与其他数字系统进行串行通信时,应用FPGA实现UART16550,对于串行数据的传输有很大改善。文章深入分析了串行通信原理和UART16550的基本结构,使用FPGA实现其功能,并进行了仿真验证。该设计稳定、可靠,可以灵活地嵌入到多种通信系统当中。     

基于灰色层次分析法的海上编队预警探测体系效能分析

为了有效分析海上编队预警探测体系作战效能,根据海上编队预警探测体系及其作战任务特点,建立海上编队预警探测效能分析指标体系,并运用灰色层次分析法,对海上编队预警探测效能进行分析研究,得出了各效能指标对作战效能的影响。     

舰船气泡尾流数值模拟(英文)

Based on a volume of fluid two-phase model imbedded in the general computational fluid dynamics code FLUENT6.3.26, the viscous flow with free surface around a model-scaled KRISO container ship (KCS) was first numerically simulated. Then with a rigid-lid-free-surface method, the underwater flow field was computed based on the mixture multiphase model to simulate the bubbly wake around the KCS hull. The realizable k-ε two-equation turbulence model and Reynolds stress model were used to analyze the effects of turbulence model on the ship bubbly wake. The air entrainment model, which is relative to the normal velocity gradient of the free surface, and the solving method were verified by the qualitatively reasonable computed results.     

On-line adaptive repetitive controller for power factor correction systems

When the fundamental frequency is shifting, it is hard for traditional repetitive controller to work at the resonant frequencies. In this paper, a novel adaptive repetitive controller for power factor correction systems is proposed to suppress the current harmonics. Through the controller, the shifting sampling times of the repetitive controller in a fundamental period can be obtained. Mathematical analysis, simulations and physical experiments have validated the effectiveness of the adaptive repetitive controller.