Since you don't want to answer to the very valid tamil's question about your NLS_TERRITORY setting, I'll assume you are in one of those territories where week starts on MONDAY. (If according to your NLS settings your week starts on SUNDAY, you'll have to modify the following function accordingly):
CREATE OR REPLACE FUNCTION my_non_iso_week (p_date DATE)
l_first_day := TO_CHAR(TRUNC(p_date, 'YYYY'), 'D');
IF TO_CHAR(p_date, 'D') >= l_first_day THEN
l_result := TO_NUMBER(TO_CHAR(p_date, 'WW'));
l_result := TO_NUMBER(TO_CHAR(p_date, 'WW'))+1;
Jurij Modic ASCII a stupid question, get a stupid ANSI
24 hours in a day .... 24 beer in a case .... coincidence?
If you had clearly posted your requirement, many people would have given the answers.
If the first week contains only 2 days (Jan 1, 2005 and Jan 2, 2005 only), your weekly scheduling algorithm (I assume) program may not work correctly. You need to code much more than if you use standard ISO week.