基于Linux的嵌入式技术的研究及应用

随着嵌入式系统的广泛应用,嵌入式Linux已受到越来越多的关注.本文介绍了Linux作为嵌入式操作系统的优势,如何将一个标准的Linux操作系统构建成一个面向应用的嵌入式操作系统,以及嵌入式Linux的应用和嵌入式Linux在未来发展中面临的巨大挑战.     

嵌入式Linux设备驱动程序开发

随着Linux操作系统日益被人们所接受,许多公司企业都使用Linux作为开发平台.文章主要阐述了嵌入式Linux设备驱动程序的概念;剖析了嵌入式Linux设备驱动程序的通用模块和具体开发流程;说明了驱动程序与内核之间的关系,进一步通过实例论述如何设计和编写模块化的嵌入式Linux设备驱动程序,以及解释驱动程序的关键代码.     

嵌入式Linux的精密控制系统解决方案

嵌入式Linux操作系统相对WinCE、pSOS、PalmOS有很多优点,有取代其他嵌入式操作系统的趋势,它使得构造一个大型机器的复杂控制系统变得简单和容易.研究解决了将嵌入式Linux操作系统应用到精密控制系统中的一些关键问题,给出构造其控制器软、硬件设计的思路和方法.     

基于Linux的嵌入式系统构建

Linux已经成为一种重要的嵌入式操作系统.介绍了基于Linux操作系统构建嵌入式系统的步骤和方法,从boodoader(主要是U-Boot的使用方法)的设置,内核配置及编译和根文件系统的配置三方面论述了如何定制嵌入式Linux.     

基于嵌入式Linux操作系统GTK在自动检票机软件开发中的应用

本文分析了自动检票机的特点,介绍了嵌入式Linux操作系统下集成的GTK库在嵌入式Linux操作系统下自动检票机软件开发中的应用。     

嵌入式Linux操作系统实时控制的改进

本文对通过嵌入式Linux操作系统的分析，提出屏蔽Linux虚存机制和改变调度策略的内核修改方案，使嵌入式Linux成为具有硬实时能力的操作系统，为嵌入式应用系统设计提供了一个新的思路。     

基于嵌入式Linux的实时性改进的研究与应用

主要介绍Linux操作系统在实时方面的缺陷及实时性改进方法,包括对Linux内核进行改造的内部实时性改进以及在Linux底层增加实时内核的外部实时性改进,最后与嵌入式系统相结合,说明了嵌入式Linux可广泛应用于信息家电、嵌入式因特网、掌上电脑及各种工业控制领域.     

基于嵌入式Linux电子书的设计与实现

设计并实现一款基于嵌入式Linux的便携式电子书,具有配置字体大小和颜色、字体格式选择、阅读记录保存、文件搜索、触摸操作等功能.系统的硬件平台选用了S3C2440,操作系统移植了嵌入式Linux.     

普通Linux实时应用的局限性分析

Linux应用于嵌入式系统有很大的优势,但在大多数嵌入式系统中操作系统要求实时性,而实时性不强是Linux应用于实时环境的主要缺点,文中分析了普通Linux不能直接用于实时系统的原因,并介绍了Linux实时改造、调度算法改造的常用方法.     

Linux体系结构及嵌入式Linux的移植方法

嵌入式系统是以应用为中心 ,以计算机技术为基础 ,软硬件均可裁剪 ,适应应用系统对功能、可靠性、成本、体积、功耗严格要求的专用计算机系统 .而Linux作为一种优秀的免费操作系统 ,近几年在嵌入式领域异军突起 ,成为了最有潜力的嵌入式操作系统 .本文通过Linux体系结构的分析 ,以及一个移植Linux的具体范例 ,具体介绍了嵌入式Linux的移植方法 .     

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