With difference from the way that traditional methods perform by accumulating the frequency of keywords . we propose a new metrical function that employs the rs - based entropy by comparing function values to measure the feature of web pages . besides , according to the unstructured and heterogenous characteristics of www , the effect of hypertext tags to keywords " weigh has been taken into account to obtain the most effective keywords for document classification 有别于传统的对关键字频度进行累加的方法，本文提出了基于信息熵的文本关键词测度函数，通过对关键词函数值进行比较，获取对文本分类最具影响性的关键词序列；同时，针对web上异质、非结构化信息的特点，该分类算法还考虑了超文本标记对关键词权值的影响。
Then the research of algorithms of texture - based image retrieval is devised from the following three aspects : 1 . texture - based image retrieval algorithms in spatial domain : perceptual - based tamura texture feature is analyzed ; run - length texture analyzing algorithm is improved ; four laws " texture operators which perform better in texture analyzing are achieved 空间域纹理分析方法方面，分析了对应于人眼视觉感受的tamura纹理特征，将游程长度纹理分析算法改进为游程累加的纹理检索算法；总结出在基于纹理特征的图象检索中四个有效的laws纹理能量算子。
Based searching the code phase parallel and carrier frequency serially at the same time , this dissertation uses differentially coherent combining to combine the coherent result of multiple correlators to improve the snr of the received signal , so that it can acquire the weak gps signals , i . e . signals down to ? 147dbm received power 本文给出了一种在伪码并行、载波串行二维搜索的基础上,对多个相关器的相关结果进行差分相干累加的方法,以积累能量,提升输入信号的信噪比,可以在较短时间内成功捕获信噪比为- 40db的gps信号。
