Data compression using a word-based model and revised arithmetic coding method.
标签： compression arithmetic word-based revised
上传时间： 2013-12-24
上传用户：zsjinju
We address the problem of predicting a word from previous words in a sample of text. In particular, we discuss n-gram models based on classes of words. We also discuss several statistical algorithms for assigning words to classes based on the frequency of their co-occurrence with other words. We find that we are able to extract classes that have the flavor of either syntactically based groupings or semantically based groupings, depending on the nature of the underlying statistics.
标签： predicting particular previous address
上传时间： 2016-12-26
上传用户：xfbs821
) Compression using huffman code -with a number of bits k per code word -provide huffman table Huffman coding is optimal for a symbol-by-symbol coding with a known input probability distribution.This technique uses a variable-length code table for encoding a source symbol. The table is derived in a particular way based on the estimated probability of occurrence for each possible value of the source symbol .Huffman coding uses a specific method for representing each symbol, resulting in a prefix code that expresses the most common characters using shorter strings of bits than those used for less common source symbols.The Huffman coding is a procedure to generate a binary code tree.
标签： code Compression huffman provide
上传时间： 2017-05-30
上传用户：yuchunhai1990
基于TMS320F2812 光伏并网发电模拟装置PROTEL设计原理图+PCB+软件源码+WORD论文文档,硬件采用2层板设计，PROTEL99SE 设计的工程文件，包括完整的原理图和PCB文件，可以做为你的学习设计参考。 摘要：本文实现了一个基于TMS320F2812 DSP芯片的光伏并网发电模拟装置，采用直流稳压源和滑动变阻器来模拟光伏电池。通过TMS320F2812 DSP芯片ADC模块实时采样模拟电网电压的正弦参考信号、光伏电池输出电压、负载电压电流反馈信号等。经过数据处理后，用PWM模块产生实时的SPWM 波，控制MOSFET逆变全桥输出正弦波。本文用PI控制算法实现了输出信号对给定模拟电网电压的正弦参考信号的频率和相位跟踪，用恒定电压法实现了光伏电池最大功率点跟踪（MPPT），从而达到模拟并网的效果。另外本装置还实现了光伏电池输出欠压、负载过流保护功能以及光伏电池输出欠压、过流保护自恢复功能、声光报警功能、孤岛效应的检测、保护与自恢复功能。系统测试结果表明本设计完全满定设计要求。关键词：光伏并网，MPPT，DSP Photovoltaic Grid-connected generation simulator Zhangyuxin，Tantiancheng，Xiewuyang(College of Electrical Engineering, Chongqing University)Abstract: This paper presents a photovoltaic grid-connected generation simulator which is based on TMS320F2812 DSP, with a DC voltage source and a variable resistor to simulate the characteristic of photovoltaic cells. We use the internal AD converter to real-time sampling the referenced grid voltage signal, outputting voltage of photovoltaic, feedback outputting voltage and current signal. The PWM module generates SVPWM according to the calculation of the real-time sampling data, to control the full MOSFET inverter bridge output sine wave. We realized that the output voltage of the simulator can track the frequency and phase of the referenced grid voltage with PI regulation, and the maximum photovoltaic power tracking with constant voltage regulation, thereby achieved the purpose of grid-connected simulation. Additionally, this device has the over-voltage and over-current protection, audible and visual alarm, islanding detecting and protection, and it can recover automatically. The testing shows that our design is feasible.Keywords: Photovoltaic Grid-connected，MPPT，DSP 目录引言 11. 方案论证 11.1. 总体介绍 11.2. 光伏电池模拟装置 11.3. DC-AC逆变桥 11.4. MOSFET驱动电路方案 21.5. 逆变电路的变频控制方案 22. 理论分析与计算 22.1. SPWM产生 22.1.1. 规则采样法 22.1.2. SPWM 脉冲的计算公式 32.1.3. SPWM 脉冲计算公式中的参数计算 32.1.4. TMS320F2812 DSP控制器的事件管理单元 42.1.5. 软件设计方法 62.2. MPPT的控制方法与参数计算 72.3. 同频、同相的控制方法和参数计算 8
标签： tms320f2812 光伏 并网发电 模拟 protel pcb
上传时间： 2021-11-02
上传用户：
LED路灯测试标准及试验方法 Word
上传时间： 2013-08-03
上传用户：eeworm
图解Word 2000中文版
上传时间： 2013-05-28
上传用户：eeworm
New-尚未归类-412册-8.64G Word.2003.Excel.2003商务办公与应用-287M.zip
上传时间： 2013-04-24
上传用户：410805624
谭浩强C语言word版，总共十三个部分，是一本很经典的c语言教程
上传时间： 2013-06-24
上传用户：tyg88888
谭浩强C语言教程Word版.rar 谭浩强C语言教程Word版.rar
上传时间： 2013-07-11
上传用户：stella2015
资料->【E】光盘论文->【E1】斯坦福博士论文->02 calgary PhD A Java-Based Wireless Framework for Location-Based Services Applications.pdf
标签： Location-Based Applications Java-Based Framework
上传时间： 2013-07-02
上传用户：亚亚娟娟123
