基于ATMEGA128的超声波倒车雷达的设计

本文针对车辆碰撞追尾事故,给出了汽车倒车雷达系统的软、硬件以及实时超声测距的原理与实现过程。该系统以AT-MEGA128作为核心处理器,实现了汽车倒车雷达系统的超声波测距。     

汽车防追尾碰撞系统的研制

研制了一种自动控制的汽车防追尾碰撞系统。汽车正常行驶时,该系统处于非工作状态,当后车车头非常接近前车车尾时,该系统将发出防追尾警告,在发出警告后,如果驾驶员没有采取制动减速措施,该系统便启动紧急制动装置,以避免发生追尾事故。汽车防追尾碰撞系统具体组成如下:(1)行车环境监测系统由测量车间距离和前面车辆方位的激光扫描雷达及能够判定路面状态的道路传感器所组成。通过发出脉冲激光对前方道路状况进行监测,并能监测弯道上的障碍物。最小的激光扫描雷达监测范围为120ｍ。(2)防追尾碰撞判断分为两步:①从激光扫描雷达所测的距离及…     

适用于汽车追尾归避的传感检测技术

汽车追尾是高速公路典型而严重的交通事故 ,而利用激光技术和雷达技术可以检测汽车间距 ,确保安全距离 ,还可以避免发生汽车追尾事故的技术方案 :既可以降低汽车追尾发生的可能性 ,又可以明显减少行车安全距离 ,从而显著提高高速公路交通流量     

交通事故分析定性推理方法

定性推理是人工智能研究的新领域,广泛用于物理过程的解释。文章首先简述了定性推 理的基本原理,然后利用QSIM算法进行了汽车追尾过程的定性推理,最后指出应用模式匹配的 方法可以断定某一具体汽车追尾交通事故的原因。     

一种基于AT89S52的车辆防追尾预警系统设计

在汽车防撞模型的基础上分析了汽车的制动过程,并设计了一种基于AT89S52的车辆防追尾预警系统。当检测到前方车辆在行驶中对本车构成危险时,声光预警模块开始工作,及时提示驾驶员采取制动等相应措施避免车辆追尾。实验表明,该系统可以根据实测距离和自车车速,准确地判断出安全制动距离并给出预警界限。     

基于图像处理技术的汽车追尾预警系统的研究

如何防止高速公路中汽车追尾是智能交通系统所要急待解决的问题.本文利用中心透视原理和图像处理的方法可以解决车道识别,车辆识别和车间距测量的关键难点,达到高速公路汽车追尾预警的目的.实验结果表明效果良好,算法简便,可以有很好的实时性.     

基于CAN总线的无人车车载无线传输终端设计

针对无人驾驶汽车运行状态的监控问题,设计了以CAN总线和嵌入式技术为核心的车辆参数数据采集和远程监控系统,基于核心处理器STM32F107搭建了终端的硬件系统,介绍了汽车CAN总线接口设计、串行接口设计和语音报警模块电路设计,监控端使用面向对象的界面化设计。应用结果表明,系统的实时性强、稳定性好,可以方便地远程观测无人驾驶汽车的运行参数。     

基于图像处理技术的汽车追尾预警系统的研究

如何防止高速公路中汽车追尾是智能交通系统所要急待解决的问题．本文利用中心透视原理和图像处理的方法可以解决车道识别，车辆识别和车间距测量的关键难点，达到高速公路汽车追尾预警的目的．实验结果表明效果良好，算法简便，可以有很好的实时性．     

基于开放式多媒体应用平台的汽车安全监测系统设计

采用以TI达芬奇技术芯片为核心处理器的硬件平台,以依据硬件裁剪定制的Linux系统为基础,设计开发了基于计算机视觉的汽车安全系统.该系统具有超速预警、安全车距预警、事故求助、车辆位置获取和车辆防盗、防抢等功能,且系统体积小、功耗低、使用方便,易于功能扩展和升级,在高速公路上开展安全监测试验表明,文中提出的算法漏检率低于5%,误检率低于0.5%.      

基于嵌入式系统的汽车检测系统研究与设计

将嵌入式实时系统、CAN总线和多传感器信息融合技术集成在一起,设计出了汽车检测线的集中/分布式实时数据的采集系统。提出三级分布式汽车检测线测控系统,开发基于μC/OS-II实时操作系统的汽车技术状态检测体系。研究适合于汽车技术状态检测平台的实时多任务调度算法,解决优先级反转和死锁问题。基于嵌入式实时系统的汽车检测线测控系统,可以减少检测线中工控机和布线的数量,可以准确、实时的完成汽车综合性能数据的检测任务。     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to