Symptom :        
       After startup oracle database in sqlplus , the alert log were written oracle database error like below
      
ORA-07445: exception encountered: core dump [nttaddr2bnd()+1152] [SIGSEGV] [ADDR:0x0] [PC:0x73AC842] [Address not mapped to object]
......
Sweep Incident[1243(number)]: completed
found dead dispatcher
......
(Database: 11.1.0.6 OS: REDHAT ES5.3 64bit)

      Solution:
     Comment out the dispatcher parameter of oracle database .
     e.g. *.dispatchers='(PROTOCOL=TCP) (SERVICE=orclXDB)'