Read previous article written before on Topic Link below:
Business Intelligence reports are generally created to un-structured or semi structured business Problems which covers Decision support system DSS, Management support system MIS.
To Know more : Read: http://sandyclassic.wordpress.com/2013/01/31/strategic-information-systems-will-be-in-focus-again-next-5-yrs/
Business Intelligence Reporting solution can develop reports of varying requirements from Nowadays from operation to BI due to pervasive nature of BI to Exit at level of Transaction processing System TPS at Knowledge level, to Office Automation system OAS at lowest operational level where operational reports about daily status is gerally used from ERP.
Typical hierarchy of Information systems from Decision Support system at top to lowest Office automation system.
Customising Cognos Authentication mechanism for integration is first step see details
How to Customize Cognos to any specific non-existent customisation using SDK. Read
If data is completely unstructured data which cannot be analysed by traditional BI system but requiring Hadoop, Hive , HBase then customisation has to integrate Big data system Read: