orcl> select name,value from v$parameter where name in ('processes','sessions');

NAME                 VALUE
-------------------- --------------------
processes            150
sessions             248

orcl> alter system set processes=1000 scope=spfile;

System altered.

orcl> alter system set sessions=1100 scope=spfile;

System altered.

orcl> startup force
ORACLE instance started.

Total System Global Area  523108352 bytes
Fixed Size                  1384664 bytes
Variable Size             402657064 bytes
Database Buffers          113246208 bytes
Redo Buffers                5820416 bytes
Database mounted.
Database opened.
orcl> select name,value from v$parameter where name in ('processes','sessions');

NAME                 VALUE
-------------------- --------------------
processes            1000
sessions             1522

orcl> select * from v$version;

BANNER
--------------------------------------------------------------------------------
Oracle Database 11g Enterprise Edition Release 11.2.0.2.0 - Production
PL/SQL Release 11.2.0.2.0 - Production
CORE    11.2.0.2.0      Production
TNS for 32-bit Windows: Version 11.2.0.2.0 - Production
NLSRTL Version 11.2.0.2.0 - Production

orcl>