Make This Code More efficient

SELECT PROJECT_ID,
SUB_PROJECT_ID,
SHORT_NAME,
ACTIVITY_SEQ,
Prjrep_Timman_API.Get_Job_Name(SHORT_NAME,
SHORT_NAME,
SHORT_NAME,
SHORT_NAME) SHORT_NAME_DESC,
'' REPORT_COST_CODE,
0 INTERNAL_QUANTITY,
sysdate - 7 ACCOUNT_DATE,
OBJID,
OBJVERSION
FROM activity_ext k
WHERE activity_responsible =
company_person_API.get_person_id('10', '1036') AND
state = activity_api.Finite_State_Decode__('Released') AND
(sysdate BETWEEN trunc(early_start) AND trunc(early_finish)
OR
(early_finish BETWEEN
CALENDAR_API.Get_First_Week_Day(sysdate) AND sysdate)) AND
1 NOT IN (select DISTINCT 1
FROM PROJECT_TRANSACTION_NO_ACCESS t
WHERE t.company_id = '10' AND t.emp_no = '1036' AND
t.account_date BETWEEN
CALENDAR_API.Get_First_Week_Day(sysdate) AND
CALENDAR_API.Get_Last_Week_Day(sysdate) AND
k.activity_seq = t.activity_seq)


Can anyone tell me a way to increase the efficiency of the above query segment.
Basically I'm looking for more efficient syntax other than IN in that sub query.

What is the sub query supposed to be doing?

Instead of using 'IN' opeartor try to use 'EXISTS' operator so that u will not need to fetch the records from the database.

Lose the
'select DISTINCT 1'
as well - make it