算法、em随堂课件本包括示例代码题库和声音等

EDUCATIONTOCREATEABRIGHT 者在本课程使用，不得在课程范围外向任何第散播。任何其他人或者机构不得盗版、、仿造其中的创意和 EDUCATIONTOCREATEABRIGHT

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EDUCATIONTOCREATEABRIGHT 6 条件概率

EDUCATIONTOCREATEABRIGHTP(A|B)P( 发生之后，对 P(B)P(A)*P(B|A)P(A')*P(B|A')nP(B)PAi*PB|Ain7EDUCATIONTOCREATEABRIGHTEDUCATIONTOCREATEABRIGHT

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EDUCATIONTOCREATEABRIGHT朴 (NaiveBayes，NB)是基于“特征之间是独立的”这一朴素假设， Py|x,x

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EDUCATIONTOCREATEABRIGHT计算过程中，分母有可能为空，经常使用IDF(逆文件频率)来替代DF，此时的权重等于TF* 换为：TF*log(IDF+1)

EDUCATIONTOCREATEABRIGHT EDUCATIONTOCREATEABRIGHT把某个研究系统中涉及到的 网络(BayesianNetwork)，又称有向无环图模型(directedacyclicgraphicalmodel,DAG)，是一种概率图模型，根据概率图的拓扑结构， 量{X1,X2,...,Xn}及其N组条件概率分布(ConditionalProbabililtyDistributions,CPD)的性质 EDUCATIONTOCREATEABRIGHT EDUCATIONTOCREATEABRIGHT EDUCATIONTOCREATEABRIGHTP(a,b,c)P(c|a,EDUCATIONTOCREATEABRIGHTaabcEDUCATIONTOCREATEABRIGHTn(1x2,...,xn)P(xn|x1,x2,...,xn1)...P(x2|1)P(1n(1x2,...,xn)P(xi|x1,x2,...,xi1)ABECABECD“正常 网

EDUCATIONTOCREATEABRIGHTp(x1,x2,x3,x4,x5,x6,x7)(1)(2)(3)(4|x1,x2,x3)p(x5|x1,x3)p(x6|x4)p(x7|x4,R01R0101EDUCATIONTOCREATEABRIGHTRS00100110011101RSJB RSJBR01S01 pS1|B1,J1pS1,B1, p pB1,J1,R,S

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pJ1|RpB1|R1,SpR pJ1|RpB1|R,S0.0344

EDUCATIONEDUCATIONTOCREATEABRIGHTcab条件独立：tailtoP(a,b,c)P(c)P(b|c)P(a|cabP(a,b,c)/P(c)P(b|c)P(a|cabpa,b|cpa,b,c/pa,b|cpa|cp(b|EDUCATIONTOCREATEABRIGHT条件独立：headtoacb acbpa,b,c/P(a,b,c)P(a)P(c|a)P(b| p(a)p(c|a)p(b|c)/pa,cpb|