UML Use Case Diagram Cheatsheet

UML Use Case Diagrams show a system or application; then they show the people, organizations, or other systems that interact with it; and finally, they show a basic flow of what the system or application does

The Meaning of Software Architecture

The software architecture of a program or computing system is the structure or structures of the system, which comprise software elements, the externally visible properties of those elements, and the relationships among them