公路工程试验检测数据处理问题探析

在公路工程的施工技术管理中,工程试验检测是一个重要环节,同时也是公路施工质量控制和工程竣工验收工作中不可或缺的一个关键步骤。针对这样一个关键环节,从数据表达和误差表示两个方面分析公路工程试验检测数据处理问题,可供参考借鉴。     

二次蒸发制备的CuxS薄膜特性研究

在玻璃基底上通过两次蒸发的新技术制备SuxS薄膜，硫在衬底温度为160℃-200℃时与淀积在衬底上的铜直接发生反应，生成CuxS薄膜，实验发现，生成的CuxS薄与衬底温度有很大关系。160℃时生成的CuxS呈黄绿色，而在190℃左右生成的多晶状的CuxS薄膜，颜色为深绿色，通过XRD、SEM、TS等方法样品的组织结构进行了研究和讨论。     

Multivariable speed synchronisation for a parallel hybrid electric vehicle drivetrain

In this article, a new drivetrain configuration of a parallel hybrid electric vehicle is considered and a novel model-based control design strategy is given. In particular, the control design covers the speed synchronisation task during a restart of the internal combustion engine. The proposed multivariable synchronisation strategy is based on feedforward and decoupled feedback controllers. The performance and the robustness properties of the closed-loop system are illustrated by nonlinear simulation results.     

提高标准件模具寿命的有效途径

在汽车标准件的生产过程中,模具起着主导作用,只有提高模具寿命,才能起到事半功倍的效果。有效提高标准件模具的寿命,除了需要合理选用模具的材料,合理设计模具的结构,做好模具的热处理以及加工与抛光外,还要选用恰当的润滑剂和精度高的设备,同时要加强管理,提高操作者的素质。     

发动机缸盖机加线一站式随行托盘的应用

发动机缸盖型号多、更新换代快,便建设了以随行托盘为主要夹具的生产线,并充分利用随行托盘的优势,两种方式定位,一站式使用,数据追溯,机械防反,大为提高了生产线的柔性化,本文将从随行托盘的机械结构、RFID数据结构和工艺路线来分析随行托盘的应用性和优势所在。     

From Twitter to detector: Real-time traffic incident detection using social media data

The effectiveness of traditional incident detection is often limited by sparse sensor coverage, and reporting incidents to emergency response systems is labor-intensive. We propose to mine tweet texts to extract incident information on both highways and arterials as an efficient and cost-effective alternative to existing data sources. This paper presents a methodology to crawl, process and filter tweets that are accessible by the public for free. Tweets are acquired from Twitter using the REST API in real time. The process of adaptive data acquisition establishes a dictionary of important keywords and their combinations that can imply traffic incidents (TI). A tweet is then mapped into a high dimensional binary vector in a feature space formed by the dictionary, and classified into either TI related or not. All the TI tweets are then geocoded to determine their locations, and further classified into one of the five incident categories.We apply the methodology in two regions, the Pittsburgh and Philadelphia Metropolitan Areas. Overall, mining tweets holds great potentials to complement existing traffic incident data in a very cheap way. A small sample of tweets acquired from the Twitter API cover most of the incidents reported in the existing data set, and additional incidents can be identified through analyzing tweets text. Twitter also provides ample additional information with a reasonable coverage on arterials. A tweet that is related to TI and geocodable accounts for approximately 5% of all the acquired tweets. Of those geocodable TI tweets, 60–70% are posted by influential users (IU), namely public Twitter accounts mostly owned by public agencies and media, while the rest is contributed by individual users. There is more incident information provided by Twitter on weekends than on weekdays. Within the same day, both individuals and IUs tend to report incidents more frequently during the day time than at night, especially during traffic peak hours. Individual tweets are more likely to report incidents near the center of a city, and the volume of information significantly decays outwards from the center.     

Virtual 3D city model as a priori information source for vehicle localization system

This paper aims at demonstrating the usefulness of integrating virtual 3D models in vehicle localization systems. Usually, vehicle localization algorithms are based on multi-sensor data fusion. Global Navigation Satellite Systems GNSS, as Global Positioning System GPS, are used to provide measurements of the geographic location. Nevertheless, GNSS solutions suffer from signal attenuation and masking, multipath phenomena and lack of visibility, especially in urban areas. That leads to degradation or even a total loss of the positioning information and then unsatisfactory performances. Dead-reckoning and inertial sensors are then often added to back up GPS in case of inaccurate or unavailable measurements or if high frequency location estimation is required. However, the dead-reckoning localization may drift in the long term due to error accumulation. To back up GPS and compensate the drift of the dead reckoning sensors based localization, two approaches integrating a virtual 3D model are proposed in registered with respect to the scene perceived by an on-board sensor. From the real/virtual scenes matching, the transformation (rotation and translation) between the real sensor and the virtual sensor (whose position and orientation are known) can be computed. These two approaches lead to determine the pose of the real sensor embedded on the vehicle. In the first approach, the considered perception sensor is a camera and in the second approach, it is a laser scanner. The first approach is based on image matching between the virtual image extracted from the 3D city model and the real image acquired by the camera. The two major parts are: 1. Detection and matching of feature points in real and virtual images (three features points are compared: Harris corner detector, SIFT and SURF). 2. Pose computation using POSIT algorithm. The second approach is based on the on–board horizontal laser scanner that provides a set of distances between it and the environment. This set of distances is matched with depth information (virtual laser scan data), provided by the virtual 3D city model. The pose estimation provided by these two approaches can be integrated in data fusion formalism. In this paper the result of the first approach is integrated in IMM UKF data fusion formalism. Experimental results obtained using real data illustrate the feasibility and the performances of the proposed approaches.     

牡绥铁路双丰隧道辅助坑道设计研究

双丰隧道是牡绥铁路最长的隧道和重点控制工程,其辅助坑道设置对隧道建设本身及牡绥铁路整体建设都具有重要的意义。隧道开工后因施工组织受客观条件影响,先后将设计的2座斜井由单车道变更为双车道;在2号斜井工区率先进入第三系泥岩后,开挖变形大,易发生涌水涌泥,施工受阻,通过对比研究斜井、迂回平导方案,推荐增加迂回平导辅助1、2号斜井工区施工;详细介绍斜井断面的拟定及新增迂回平导平、纵断面设计及优化和内轮廓拟定等,最终有效保证了隧道的施工安全和顺利贯通。     

新型舰载ESM信号处理系统

随着雷达技术的发展，电磁环境越来越密集，雷达信号的类型超来超复杂，这就对ＥＳＭ信号处理提出了更高的要求。基于目前ＥＳＭ信号的处理方法，本文提出了一种先进的工程上可实现的新一代舰载ＥＳＭ信号处理系统。     

新的汽车牌照识别系统及其成像技术

介绍了一种高性能的汽车牌照识别系统及其成像技术。系统采用了新的成像控制和闪光灯补光技术，使其成像特别适合牌照区域分割和字符识别，成像质量完全不受实际应用环境中强烈的光线变化的影响，从而达到较高的全天候识别率和实际应用的要求。给出了系统在全天候条件下的成像效果和牌照识别效果．结果显示系统可在全天候条件下获得高质量的图像。