UML Sequence Diagram. Design Elements

This UML sequence diagram of order processing center (OPC) was created on the base of sequence diagram from the software architecture documentation wiki of the Software Engineering Institute (SEI) of Carnegie Mellon University (CMU).
[wiki.sei.cmu.edu/ sad/ index.php/ Image:OPCRuntimeRefinementView_ PP2.png]
"Order processing is the process or work-flow associated with the picking, packing and delivery of the packed items to a shipping carrier. Order processing is a key element of order fulfillment. Order processing operations or facilities are commonly called "distribution centers"." [Order processing. Wikipedia]
This order processing center UML sequence diagram example was created using the ConceptDraw PRO diagramming and vector drawing software extended with the ATM UML Diagrams solution from the Software Development area of ConceptDraw Solution Park.

This example of bank ATM UML activity diagram was created on the base of UML use case diagram of automated teller machine from the course "Thinking in Java, 2nd edition, Revision 9" by Bruce Eckel published on the website of the Computer Science and Electrical Engineering Department of the University of Maryland, Baltimore (UMBC).
"If you are designing an auto-teller, for example, the use case for a particular aspect of the functionality of the system is able to describe what the auto-teller does in every possible situation. Each of these “situations” is referred to as a scenario, and a use case can be considered a collection of scenarios. You can think of a scenario as a question that starts with: “What does the system do if...?” For example, “What does the auto-teller do if a customer has just deposited a check within the last 24 hours, and there’s not enough in the account without the check having cleared to provide a desired withdrawal?”
Use case diagrams are intentionally simple to prevent you from getting bogged down in system implementation details prematurely...
Each stick person represents an “actor,” which is typically a human or some other kind of free agent. (These can even be other computer systems, as is the case with “ATM.”) The box represents the boundary of your system. The ellipses represent the use cases, which are descriptions of valuable work that can be performed with the system. The lines between the actors and the use cases represent the interactions.
It doesn’t matter how the system is actually implemented, as long as it looks like this to the user."
[csee.umbc.edu/ courses/ 331/ resources/ tij/ text/ TIJ213.gif]
This automated teller machine (ATM) UML use case diagram example was created using the ConceptDraw PRO diagramming and vector drawing software extended with the ATM UML Diagrams solution from the Software Development area of ConceptDraw Solution Park.