ARMI is a project management tool used for doing stakeholder analysis for a project. It identifies the responsibilities of the personnel involved in the project.
A - Approver / Sponsor, one who authorizes and approves the project and its progress
R - Resource, a subject matter expert (SME) whose skills and knowledge are required for specific duration
M - Member, a full-time project team member
I - Interested Party, someone who needs to be kept informed about the project status
RACI - is a project management tool for determining the roles and responsibilities of all the personnel within the project team. It is also called as Responsibility Assignment Matrix.
R - Responsible, doer of the task / activities. There should be at least one Responsible for each task / activity
A - Accountable, owner of the task / activities. Approves the work done by Responsible. There must be only one Accountable for each task / activity
C - Consulted, typically a subject matter expert who is consulted while completing a task / activity. Usually is a two-way communication
I - Informed, those who are updated about completion of task / activity. Usually is a one-way communication
An application oriented question on the topic along with responses can be seen below. The best answer was provided by Sumanta Das on 30th November 2017.