Hi Dileep - Integration Events are for loading data into Ariba and to push transactional data to ERP systems like SAP. In the Administration console of Ariba, they refer to Integration Events as "Data Import/Export". Some examples of loading data into Ariba are Users, Suppliers, Accounts. Transactional push examples are Purchase Order Push, Receipt Push, Invoice Push. There are different channels to import/export. There's the File Channel which uses CSV or Excel files, and there's Web Services that leverages SOAP messages over Https. Typically data loading leverages CSV flat files, whereas transactional push leverages Web Services. For example, when integrating to SAP, the PO push can use real-time Web Services calls to SAP's Netweaver PI. There's an additional channel for intra-application data pushing between Buyer and Upstream called HTTP Channel. This channel will sync master data between the 2 applications. For instance, when loading Users or Suppliers into Buyer, the deltas will be pushed to Upstream via the HTTP channel integration events.
Scheduled Tasks are used for processes. They are Java implementations, therefore logically you could really do anything, however some typical usages are for notifications (ex: overdue charge notification), status updates from the Ariba Network (ex: Order Confirmations), and troubleshooting (ex: Send Stuck Collaboration Requests). As the name implies, you can schedule a task to run on an interval of your choosing. Often several tasks are grouped together for batch processing. An example of this may be to Load PCard Charges, followed by Process Loaded Charges.