[데이터마이닝] 5.링크분석(Link analysis) 5.3절 연습문제(Exercise 5.3.5 )

Exercise 5.3.1 : Compute the topic-sensitive PageRank for the graph of Fig. 5.15, assuming the teleport set is:

(a) A only.

M = matrix(c(0, 1/3 ,1/3 ,1/3,
             1/2,0,0,1/2,
             1,0,0,0,
             0, 1/2 , 1/2, 0),nrow = 4)
r = matrix(c(1/4,1/4,1/4,1/4))
beta = 0.8

es = matrix(c(1,0,0,0),nrow=4)
s = 1
pre_r = r
r = (beta*M)%*%r + (1-beta)/s * es
while(pre_r != r ){
  pre_r = r
  r = (beta*M)%*%r + (1-beta)/s * es
}
r

 

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(b) A and C.

M = matrix(c(0, 1/3 ,1/3 ,1/3,
             1/2,0,0,1/2,
             1,0,0,0,
             0, 1/2 , 1/2, 0),nrow = 4)
r = matrix(c(1/4,1/4,1/4,1/4))
beta = 0.8

es = matrix(c(1,0,1,0),nrow=4)
s = 2
pre_r = r
r = (beta*M)%*%r + (1-beta)/s * es
while(pre_r != r ){
  pre_r = r
  r = (beta*M)%*%r + (1-beta)/s * es
}
r

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