BTS330
Understanding User Requirements
1
Requirements
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Steps:
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Define vision/scope
Identify users/stakeholders
Identify use cases
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Understand what interaction is happening with
the system
Identify business rules
2
Use Case Modeling
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Actor
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Represent anything outside the system
that uses the system to do something
From your stakeholder list, identify those
‘stakeholders’ that will actually use the
system  those are the actors
Use Case Modeling
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Actor
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Give them a name – use a name that
describes the role that the actor plays in
relation to the system
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i.e. Fitness Instructor, member, manager
Really a role that a person (or system, or
device) plays when using the system
Give the actor a brief description
Use Case Modeling
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Fitness Instructor
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Member
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Instructs fitness classes
Uses the club’s facilities and services
manager
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Is responsible for overseeing the operation
of the club and managing the employees
Use Case Modeling
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Actor Tip:
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Every system requires an actor to start the
system and to shut it down  the actor is
anything outside the system that
exchanges information with the system
Every system requires some sort of
maintenance to be done
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i.e. backup – actor is ‘system clock’
Use Case Modeling
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Actor
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A person, software system, department,
role, device…etc…. outside of the system
that interacts with the system
Actor
Actor
System
Actor
Use Case Modeling
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Use cases:
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Express the behaviour of the system that produce
a measurable result of value to an actor
Describe the things actors want the system to do
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i.e. query the status of an order
How do the users use the system?
Each major system ‘usage’ is a use case
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i.e. Process A Membership, Manage Fitness Classes,
Maintain Employee
8
Use Case Modeling
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Use case:
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A sequence of interactions between a
system and an external actor
Accomplishes a ‘useful’ goal; something of
value to the user
9
Use Case Modeling
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Actors communicate with the system to:
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Start a use case
Ask for some data stored in the system
which the use case presents to the actor
Change data stored in the system by
means of a dialog with the system (request
some data, change it and save it)
10
Use Case Modeling
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Use cases communicate with the actor
to:
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Report that something special has
happened in the system that the actor
should be aware of
Ask an actor for help in making a decision
needed to achieve a goal
Delegate responsibility to an actor
11
Use Case Modeling
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Identifying use cases
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For each actor list the interaction they
must have with the system
The interaction should be a ‘goal’ that the
actor wants to accomplish by using the
system
Name the interaction  use a verb to
name the interaction
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i.e. Schedule A Class, Process A Membership
Use Case Modeling
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Use cases are usually completed in a
short period of time
If parts of the use case are widely
separated in time and performed by
different actors, then those parts are
probably better as separate use cases
Use Case Modeling
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Identifying use cases tips:
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What functions will the actor want from the
system?
Does the system store information? What actors
will create, read, update, or delete that
information?
Does the system need to notify an actor about
changes in its internal state?
Are there any external events that the system
must know about? What actor informs the system
about those events?
Use Case Modeling
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Identifying use cases
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Every system starts from a vision
Vision can tell us the key features required
of the system, possible constraints and
who the stakeholders might be
In-class Exercise
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Jim’s Gym
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For Jim’s Gym who needs to acquire an automated
computer system to run his new business, the Gym
Management System is an information system that will
provide a single point of access to manage his gym. The
system will provide the capability to manage all aspects of
Jim’s business such as managing members and fitness staff,
schedule employees and fitness classes as well as a gift
shop. There will also be services such as massage therapy
and private and semi-private instruction with a fitness
instructor offered. Unlike the competition, our product will
allow members to manage their experience at Jim’s gym
through an interactive web interface where customers can
sign up for classes and services that the gym will be
offering.
In-Class Exercise
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From the vision statement:
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Stakeholders:
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Jim
Fitness instructors
Use Cases:
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Manage Members
Manage Staff
Schedule Employees
Schedule Classes
Gift Shop
Massage Therapy
Private, semi-private instruction
Sign up for classes
In-Class Exercise
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Which of these will an actor need to interact with the
system?
Which of these will require further analysis to
determine who the actors need to be and what
interaction they need to have with the system?
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Manage Members
Manage Staff
Schedule Employees
Schedule Classes
Gift Shop
Massage Therapy
Private, semi-private instruction
Sign up for classes
In-Class Exercise
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For your business, start with your vision
statement
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Identify who the stakeholders are
Identify the use cases by listing the
interaction the actor needs to have with
the system (you might be able to identify
some of the interaction from your vision
statement)