How my i improve the time's response access disk

hello gurus,

      I try to be clear. my database is in version 11.2.0.3 in a server Linux x86-64 redhat 6.8.

I execute this query,(sqlid: bjxpsu76dkj40) by my forms oracle.

  therefore :

      1 - when I execute these query First time in the morning every day then my response's time is 35 mints average. ( see bad tkprof )

      2 - when I execute a second times and after n times this query by the same forms then my response's time is 3 mints average. ( see good tkprof )

Conclusion :

     my I/O are not correct then I would like improve my I/O performance.

     my data are stored in a SAN fiber 8Gb, then my responsible system tell to me it is correct then how may I control it ?