汽车荷载作用下空心板桥空间动力冲击效应

根据空心板桥结构特点,运用梁壳组合模型和铰接梁模型模拟空心板桥,考虑桥面不平顺影响,建立三维车桥耦合振动模型分析空心板桥动力特性,研究不同车速、行车道位置及路面状况对空心板桥冲击系数的影响,并将理论值与实测值进行对比.研究结果表明：空心板桥动力特性梁壳组合模型与实测值更接近;车速在12～16 m/s时,空心板桥位移冲击系数随速度有明显共振节拍,随着路面不平顺恶化,速度节拍影响不明显;位移冲击系数与应变冲击系数并不完全一致,跨中位移冲击系数略大于应变冲击系数,1/4位置应变冲击系数略大于位移冲击系数;实测与数值模拟的空心板桥冲击系数均满足现行规范要求.     

新能源汽车竞争力提升策略研究

通过文献研究、调查研究和实证研究,总结出了影响新能源汽车消费的各个变量,使用SPSS 17.0统计软件对问卷数据进行了分析,得出了影响新能源汽车市场消费的3个关键因素:汽车质量因子、购买成本因子和售后服务因子,并从提升汽车质量、完善售后服务、降低成本几个方面提出了的建议。     

碳酸盐粉煤灰水泥复合胶凝材料浆体的电学特性

采用循环伏安法和交流阻抗法研究了碳酸盐粉煤灰水泥复合胶凝材料浆体的电阻率和交流阻抗等电学特性.结果表明：碳酸盐掺合料能够提高复合胶凝材料浆体的电阻率,碳酸盐和硅微粉惰性掺合料对复合胶凝材料浆体电阻率的贡献率大于粉煤灰和偏高岭土活性掺合料;碳酸盐掺合料降低了表征浆体C-S-H胶凝中导电离子的电容（Cg）;提高了表征复合胶凝材料浆体孔隙率的高频电阻（Rs）,即降低了浆体孔隙率;提高了表征浆体水化程度的低频电阻（Rct）.     

Skin detection method based on cascaded AdaBoost classifier

Skin detection has been considered as the principal step in many machine vision systems, such as face detection and adult image filtering. Among all these techniques, skin color is the most welcome cue because of its robustness. However, traditional color-based approaches poorly perform on the classification of skin-like pixels. In this paper, we propose a new skin detection method based on the cascaded adaptive boosting (AdaBoost) classifier, which consists of minimum-risk based Bayesian classifier and models in different color spaces such as HSV (hue-saturation-value), YCgCb (brightness-green-blue) and YCgCr (brightness-green-red). In addition, we have constructed our own database that is larger and more suitable for training and testing on filtering adult images than the Compaq data set. Experimental results show that our method behaves better than the state-of-the-art pixel-based skin detection techniques on processing images with skin-like background.     

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.