Page 108 - Contributed Paper Session (CPS) - Volume 2
P. 108

CPS1443 Shogo H.N. et al.
                  e.g., Uchida and Yoshida (2012). The 2-dimensional latent process { }   is
                                                                                       ≥0
                  defined by the following SDE:

                             (1)         (1)            1   2        1
                         d [    ] = ([  1  3 ] [    ] + [  5 ]) d + [     ] d ,  = [ ],
                                                                            
                                                                               0
                              (2)   2   4    (2)   6  2  3           1

                  where { }   is a 2-dimensional Wiener process. Our observation { ℎ  =0,…,
                                                                                      }
                            ≥0
                  is defined as
                                          =    + Λ 1/2   ,  = 0, … , ,
                                        ℎ   ℎ     ℎ 

                  where  Λ  is  a  2 × 2 -dimensional  positive  semi-definite  matrix,  and
                                                                                  ⋆
                   ℎ   ∼ ...   (,  ). Let us set the parameters in the simulation by Λ = 10 −4  ,
                                                                                           
                             2
                                  2
                                                                       6
                                    ⋆
                    ⋆
                   = (1, 0.1, 1) ,   = (−1, −0.1, −0.1, −1, 1, 1) ,   = 10 ,  ℎ = 6.310 × 10 −5  ,
                                                                           
                   = 63.096,  = 1.9,  = 6172,  = 162, Δ = 1.022 × 10 . The number of
                                                                           −2
                                                             
                                        
                                                   
                   
                  iteration is 1000. The following table summarises the result of the simulation:
                  the left column shows the target parameters and their true values, the middle
                  column  corresponds  to  our  proposal  method  and  the  right  one  is  for  the
                  existent  method  called  local  Gaussian  approximation  (LGA)  (Uchida  and
                  Yoshida,  2012).  The  value  without  brackets  indicate  the  mean  in  1000
                  iterations and that with brackets is the root-mean-squared error (RMSE).

                         Parameter              Our proposal         LGA (existent method)
                                 true
                     target                  mean         RMSE         mean         RMSE
                                 value
                                    −4
                                                   −4
                     Λ (1,1)     10        1.32 × 10      (3.21 ×
                                                          10 )
                       ⋆
                                                             −5
                       (1,2)       0       6.29 × 10      (6.31 ×
                                                   −6
                     Λ ⋆                                  10 )
                                                             −6
                                    −4
                                                   −4
                     Λ (2,2)     10        1.33 × 10      (3.25 ×
                                                          10 )
                       ⋆
                                                             −5
                                 1       0.997493      (0.0101)    2.045903      (1.0459)
                        ⋆
                        1
                                0.1      0.095540      (0.0073)    0.048684      (0.0514)
                        ⋆
                        2
                                 1       0.997770      (0.0103)    2.049110      (1.0491)
                        ⋆
                        3
                                −1       −1.073397     (0.2056)    −4.587123     (3.6698)
                        ⋆
                        1
                               −0.1      −0.097747     (0.1964)    0.237936      (0.6836)
                        ⋆
                        2
                               −0.1      −0.095846     (0.1931)    0.238196      (0.6808)
                        ⋆
                        3
                                −1       −1.064302     (0.2009)    −4.559194     (3.6493)
                        ⋆
                        4
                                 1       1.060123      (0.2802)    3.936379      (3.1035)
                        ⋆
                        5
                                 1       1.055244      (0.2784)    3.911360      (3.0893)
                        ⋆
                        6
                                                                      97 | I S I   W S C   2 0 1 9
   103   104   105   106   107   108   109   110   111   112   113