The Applications of Convolutional Codes to Modern Efficient Error-Correcting Coding

随着90年代初Turbo码的发现，现代纠错编码理论的发展进入了一个新的时期，级联、交织、低密度等成为近香农限高效纠错编码设计的普遍技术，而卷积码是一类高效的纠错编码，作为成员码型继续成为这些新型组合纠错编码的重要选择。本文从卷积码的基本概念出发，介绍了卷积码的定义与构造方式，详细阐述了卷积码的矩阵与多项式描述，探讨了生成矩阵的特性、构造方法和与卷积码诸多性质的关系，给出了一些设计原则，并给出了卷积码的三种图形描述方式以及它们在译码算法方面的应用。在现代纠错编码方案中，卷积码既可以作为成员码参与其中，又可以以单一码型的形式发挥作用，第三章和第四章就分别从这两个方面进行了阐述。第三章介绍了Turb...With Turbo codes found in early 90s, the modern error-correcting coding theory has come into a new stage. Concatenation, interleaving and low density become popular choices in the designing of near Shannon limit error-correcting codes. Convolutional codes are a set of efficient error-correcting codes, and they can serve as a good choice for member codes in these new combination codes. Ba...学位：工学硕士院系专业：计算机与信息工程学院电子工程系_通信与信息系统学号：20023002

Slope′s Affection on Turbo Codes′ Performance

Turbo码近年来一直是通信领域的研究重点,寻找好的分量码即是一个重要方向。Turbo码分量码编码器采用了以本原多项式作为反馈连接多项式的递归系统卷积码,以获得最大的最小码重和最大的自由距离。本文说明了另一个影响卷积码纠错能力的参量活性突发距离,提出以卷积码的斜率因子为替代参量来分析Turbo码。仿真说明在采用同一个本原多项式作为反馈连接多项式的情况下,分量码的斜率因子越大,则Turbo码的纠错性能相应越好,斜率因子可以作为评价Turbo码性能的另一个重要参数。Turbo codes are being a highlight in communication field recent years.Searching a good component encoder is an important direction.A recursive systematic convolutional encoder using a primitive polynomial as its recursive polynomial is used in Turbo codes′ component encoder,which provides the maximum minimum weight and the maximum free distance.The active burst distance affects the performance of convolutional codes too.The method of analyzing Turbo codes by the slope of convolutional codes is presented.Simulation results show that using the same recursive polynomial,performance of Turbo codes becomes better as the slope grows,which means the slope can be considered as an important parameter to estimate and optimize the Turbo codes

Applications of MATLAB in emulation of communication system

在通信系统的设计与仿真中经常会碰到一些相似的基本问题,它们都可以建立相似的数学模型,并且用数学工具或仿真工具加以解决。文中以实际项目中3个不同的通信系统模型为例,说明了建立数学模型的过程并具体阐述了如何利用MATLAB设计语言所提供的各种函数加以实现。Some basic problems often show up in the designing and simulation of communication systems. Similar mathematic models can be built up to solve them by mathematic tools or simulation tools. Three diffe-(rent) communication system models are presented in this paper, the mathematic models of them and the way to solve them by using the functions of MATLAB language are expatiated in details

面向新生的单片机入门实验课程设计与实施

选择单片机作为《大学入门指导》实验教学主题,设计一套适合大学新生的教学模式,先观察实验现象再学习理论知识,最后完成实验任务。实验内容系统性强,难度适中,主题丰富,且聚焦于单片机..

Thinking on the Teaching of Microcomputer Principle and Interface Technology Course

《微机原理与接口技术》是一门难度较大的专业基础课,剖析教学目标与学生的学习特点,针对本课程知识点和难点众多的情况探讨教学大纲的设置、教材选择、课堂教学方式等问题,并对配套实验课程的设置与实验课教学进行探讨。Microcomputer Principle and Interface Technology is a professional basic course of a great difficulty, analyzes the teaching goals and stu-dents' learning characteristics, discusses syllabus setting, textbook selection, teaching methods and other issues in view of the course knowledge point and difficulty, and presents a complete setting of the experimental course.福建省教学质量与教改工程(No.Z02109

The Growth and Effect of Critical Illness in the Senior Population the Implementation of the National Health Insurance Program in Taiwan

[[abstract]]在1995年全民健康保險開辦之前，許多的高齡人口都沒有健康或醫療保險，特別是經濟情形不佳的高齡人口因負擔不起醫療費用而無法就醫，結果使得盛行率和死亡率明顯下降，然而在1995年全民健康保險實施後，並無直覺證據證明疾病擴張，因此以生命表方式呈現全民健康保險資料庫中重大傷病與因呼吸衰竭而須長期使用呼吸器的資料，且討論為何自全民健康保險後台灣高齡人口失能情形更為嚴重

Crosshole Seismic Tomographic Inversion Using Combined Direct and Reflected Traveltimes

提出一种井间地震直达波和反射波走时联合层析反演方法。建立了基于不规则单元的地层和界面完全耦合的三维井间离散模型,并在垂直于连井截面方向上假设模型参数不变;以直达波走时和反射波走时为观测数据,地层单元节点上的慢度和反射界面节点上的深度为模型参数,并考虑平滑约束和先验约束等,建立了线性迭代联合层析反演方程。理论模型合成资料和实测资料的应用结果表明,联合层析反演能同时发挥直达波和反射波各自的优势,不但可以确定反射界面,而且能提高地层速度的分辨率和可靠性。A method for crosshole seismic tomographic inversion using combined direct and reflected traveltimes is proposed in this paper.The 3-D crosshole model is represented as a set of layers separated by the interfaces,across which the velocity may be discontinuous.Each layer is discretized by irregular hexahedral and/or tetrahedral cells and each interface is discretized by inclined planes,which are perpendicular to the crosshole section.The discrete layers couple entirely with the discrete interfaces.The model parameters are assumed to be constant in the direction vertical to the crosshole section.Both velocities at layer nodes and depths at interface nodes are simultaneously inverted using a combination of direct and reflected arrival data.The inversion process seeks a minimum-structure model that is able to explain the given traveltime data satisfactorily by inverting to minimize data misfit and model roughness norms simultaneously.The nonlinear traveltime inversion is achieved using an iterative linearized approach.The applications of this method to synthetic and real data demonstrate that the combined direct and reflected traveltime tomographic inversion can obtain more accurate medium velocity and interface depth with a higher resolution than the direct traveltime inversion.国家自然科学基金项目(41074077;41230318)资

The Principle and Application of Digital Video Codec Chip ADV611

ADV61 1是一种高压缩率 (可达 750 0 :1 )的专用视频图像压缩 /解压缩芯片。本文介绍了 ADV61 1的工作原理、功能特点等 ,并给出了基于 ADV61 1实现视频图像实时编解码的可选择方案 ,具体描述了实现高压缩率的方法。ADV611 is a chip dedicated in video image compression/decompression, which has a high compression ratio ( up to 7500:1). In this paper, The principle, function and characteristic of ADV611 are introduced, and how to realize the video compression with ADV611 based on computer and DSP is described. Finally, the specific approach to achieve the high compression ratio is presented

Imaging by a joint tomography of direct wave traveltime and reflection wave traveltime in crosswell seismic and its application

本文利用直达波的旅行时与反射波的旅行时联合反演两井之间的速度分布,在计算方法中加入声波测井获得边界上的先验信息,如慢度分布和反射层位置,可提高计算时的收敛性能与计算效率。在层析反演过程中,采用阻尼lSQr算法求解,在求解的过程中施加一定的阻尼,能有效地抑制数据误差较大时的影响,提高反演的抗噪声能力。应用正演模型验证了方法的可行性。实际资料处理表明,该方法的层析速度纵、横向分辨率较高,在井旁与声波速度吻合较好,计算精度较高。The paper discusses a joint tomography of direct wave traveltime and reflection wave traveltime in crosswell seismic.Using direct wave traveltime and reflection wave traveltime between wells with well information such as slowness distributions and reflection interface positions,this tomography method benefits a good astringency.The damp LSQR arithmetic is applied in the tomography procedure.It can effectively improve de-noise ability.Its application to the forward modeling proves its feasibility.Applications to field datasets indicate that high resolutions are obtained for both vertical and horizontal direction;and good velocity matching around the wells.国家“863”计划“油藏综合地球物理技术”课题(No.2007AA060500)资