The Framework Manager is the metadata modelling tool of IBM Cognos
Cognos Report Studio is used to create and manage more advanced reports. Report Studio is used by Report Authors.
Cognos Analysis Studio is an application to analyze and explore business data in a multidimensional manner.
Event Studio is a process (an agent) which runs in background. Event studio takes such actions as: generating emails, running reports, updating news channel in a corporate portal or communicating with other software.