Hello,
The question I asked myself, was while building a course on adomd.net.
The solution I have found, is that The administrator of SSAS server can be the application pool windows user account (it has to be in a domain).
After that, we have the choice between Roles and/or EffectiveUserName for impersonation, in case we have users connecting individually to SSAS.
A link to the course is in my signature.
Regards,
Oussama Dinia
.NET Solutions Architect
http://devmeetsbi.ghost.io/
http://www.devmeetsbi.io/catalog/3079