QQDDP

计算边介数,复杂网络，中心性计算，介数也可以计算，运用了数据结构，计算大量数据(edge betweenness，complex network， centrality)

A base-64 MIME format encoderdecoder with C source code(A base- 64 MIME format encoderdecoder with C source code)

MatLab Gray Scale by Half

：滤波 fs=400 采样频率,必须大于两倍基带信号最高频率 ts=1/fs 采样时间间隔 T=5 时间窗大小 t=0:ts:T (hf1=zeros(1,N) hf1(f<=B1&f>=-B1)=1 y1=hf1.*fftshift(y) figure subplot(211) plot(f,abs(fftshift(y))/N,f,hf1, r-- ) axis([-fs/2,fs/2,0,1.2]) title( 原信号频谱 ) xlabel( f /Hz ) subplot(212) plot(f,abs(y1)/N) title( 低通滤波，截止频率90Hz ) xlabel( f /Hz ))

这是对于二维otsu算法的实现，对灰度图像进行分割，可以较好地去除噪声对图像的影响，使图像的分割结果更准确，缺点是运行的速度大大增加，所占的内存也大大增加。

主要用于电子罗盘实验，对于新手调试入手很快(Mainly used in electronic compass experimen,For beginners, debugging starts quickl)

C语言进阶资料，一共分为八讲，提高的好资料。(Advanced C language data, a total of eight, good data to improve the.)

XListCtrl控件源码，一个很有用的列表扩展控件(CListCtrl control source, a useful list expansion control)

Clipmap 简单的算法演示，很有研究价值。 是制作大地形的极佳算法。(Clipmap method ，is very good to stud。)

tf–idf, short for term frequency–inverse document frequency, is a numerical statistic that is intended to reflect how important a word is to a document in a collection or corpus.[1]:8 It is often used as a weighting factor in information retrieval and text mining. The tf-idf value increases proportionally to the number of times a word appears in the document, but is offset by the frequency of the word in the corpus, which helps to control for the fact that some words are generally more common than others. Variations of the tf–idf weighting scheme are often used by search engines as a central tool in scoring and ranking a document s relevance given a user query. tf–idf can be successfully used for stop-words filtering in various subject fields including text summarization and classification. One of the simplest ranking functions is computed by summing the tf–idf for each query term many more sophisticated ranking functions are variants of this simple model.