Differential Privacy Location Protection Method Based on the Markov Model

Algorithm 1

Location prediction based on the Markov model (LPAM).

Input: ; // degree transition matrix

  ; // location at time k-1

  now; // current location

  ; // estimate each location

  ; // weight array

Output: result // output all predicted locations

1. FOREACH

2.  ; //cumulate is an accumulation process

3.  FOREACH

4.   ;

5.   // one step transition probability matrix P is obtained

6. FOR i=2 to n Do

7.  ; // calculate n-step transition probability matrix

8. ENDFOR

9. setZero(X); // clear X and calculate the estimate

10. FOR i=1 to n Do

11.  ; // multiplication of weight and matrix

12.  ; // calculate X

13. ENDFOR

14.  ; // output all predicted locations

15. RETURN result;