This document discusses system modeling and the Unified Modeling Language (UML). It introduces system modeling as developing abstract models of a system using different types of models. It then discusses UML as a tool for developing these models, specifically covering the activity, use case, sequence, class, and state diagram types. Each diagram type is briefly described. Examples are provided of an activity diagram modeling an ATM and use case diagrams for an ATM system, university registration system, and online shopping system. The relationships between use cases like include and extend are also covered. Finally, sequence diagrams modeling a login process and ATM transactions are shown.

1. System Modeling
elliot attipoe
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2. Objectives
• To understand how graphical models can be
used to represent software systems.
• To understand why different types of model
are required for system development.
• To introduce you to some of the diagram types
in the Unified Modeling Language (UML).
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3. System Modeling
• System modeling is the process of developing
abstract models of a system.
• Types of models
– External perspective
– Interaction perspective
– Structural perspective
– Behavioral perspective
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4. Unified Modeling Language (UML)
• A tool for developing models.
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5. UML diagram types
1. Activity diagrams - which show the activities involved
in a process or in data processing.
2. Use case diagrams - which show the interactions
between a system and its environment.
3. Sequence diagrams - which show interactions
between actors and the system and between system
components.
4. Class diagrams - which show the object classes in the
system and the associations between these classes.
5. State diagrams - which show how the system reacts
to internal and external events.
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6. Activity Diagram – ATM example
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7. Use case modeling
• A Use-case specifies the behaviour of a system
or part of a system.
• They focus on the interaction different users
have with the system from the user’s point of
view.
• This helps uncover requirements in a way that
clients find easy to understand.
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8. Formal Definitions
• Actor
– A role that a user can play.
– Examples: instructor, advisor, student.
– Actors do not have to be human.
– An actor is always outside of the system boundary, an
external entity.
• Use Cases
– Actions on a systeminitiated by an actor.
– These are the main tasks performed by each actor.
– Use cases represent complete functionality of a task.
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9. Scenario: ATM system
• Identify the users of the system and their
roles?
• Customer – check balance, deposit, withdraw,
transfer
• Bank staff – can do all that plus adding money
and paper, repair
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11. UCC registration system
• Actors
– Registration officers
– Student
– Faculty officer
– Registration staff
– Accounts
– Hall porters
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12. Online Shopping System
• Identify actors and their use cases
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13. Actor : Customer
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14. Actor : Admin
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15. <<extend>> relationship
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16. <<include>> relationship
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17. <<include>> and <<extend>> relationship
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18. Question
• A tour operator takes bookings for people who would like to tour cities by
bicycle. She employs people familiar with the local area to take groups to
interesting locations. The bookings are taken via the internet and phone,
as well as from people walking up to her office. Each tour group runs once
a day, starting from a fixed location at 9:00am. If there is a larger group
than can be handled by one tour leader the group is split and another tour
is taken at 10am by a second tour leader who is contacted as soon as the
group size exceeds a certain size.
• People have to pay before the tour starts at which point they are given a
bicycle owned by the company. They have to pay a deposit for the bicycle
which is refundable at the end of the tour.
• At the end of each day the bicycles are checked for any damage, and
repaired if necessary.
• Identify the use cases and actors that are applicable for this business.
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19. Demo on use case
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20. Sequence Diagram
• Sequence diagram is use to model the
interactions between the actors and the
objects in a system.
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21. Model login
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22. Sequence diagram for login
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23. ATM machine – insert card
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24. ATM – withdraw (sequence diagram)
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