At cognos Server- UDA and TMP files are few files which get created when a report is been run. These files will be deleted automatically after the report run is finished.
We might be in a situation when this files go big and not getting deleted after the session. At that time you can delete them manually. But if you are not able to delete manually (assuming you are having admin rights) then you need to check at cognos connection if any reports are running at background. Make sure there are no reports running in background, if they are then notify user and kill them.
An other option is to kill few services at task manager(not the cognos server related) and check whether the temp files are deleted or not.
cognos analytics uda files unable to delete
cognos analytics UDA Temp Files