Software Engineering Institute

Software Engineering Institute is Carneige Mellon 
University, they developed CMMI model which is popularly 
followed by software organisations as Standard..

SEI = 'Software Engineering Institute' at Carnegie-Mellon 
University; initiated by the U.S. Defense Department to 
help improve software development processes.

CMM = 'Capability Maturity Model', now called the CMMI 
('Capability Maturity Model Integration'), developed by the 
SEI. It's a model of 5 levels of process 'maturity' that 
determine effectiveness in delivering quality software. 

ISO 
'International Organisation for Standardization' - The ISO 
9001:2000 standard (which replaces the previous standard of 
1994) concerns quality systems that are assessed by outside 
auditors, and it applies to many kinds of production and 
manufacturing organizations, not just software.

IEEE 
'Institute of Electrical and Electronics Engineers' 

ANSI 
'American National Standards Institute', the primary 
industrial standards body in the U.S.;