1 unified modeling language michael k. wildes university of california, riverside – extension...
TRANSCRIPT
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Unified Modeling Language
Michael K. Wildes
University of California, Riverside – Extension Program
Presentation 2
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Definition
CustomerThe person who the IT personnel are building the system forThey must be the owner of the system as wellThe trick is to identify the real customerThe real customer (owner) has the checkbook
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Definition
UserThe user is one who will interact with the system
They are important as they report to the owner problems
Both the customer and the user must be satisfied !
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Definition
ActorA person or thing that interacts with a computer system
An actor can have many roles customer employee Clerk
An actor can also be another computer system
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Definition
Initiating ActorAn actor who initiates a business transaction
For example Customer who makes a purchase Employee who places timecard into time clock Client who makes a payment
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Definition
Participating ActorAn actor who is a part of the systemThey facilitate the business transactionFor example Clerk who enters the purchase into a Point of Sale
terminal Clerk who places paper in the printer Accountant who audits report Credit card authorization system
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Planning is a very critical phase
It requires much interaction between analysts, owners, and users
The preliminary investigation and the Project Specifications report must show that the system is feasible before continuing into analysis
If not, stop the process
PLANNING
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Definition
Feasibility
A project is feasible if it appears that automation will solve the user's information related problem while satisfying economic, operational, technical, organizational, environmental, and temporal constraints
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Definition
Economic Feasibility
A project is economically feasible if it appears that the solution is affordable
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Definition
Operational Feasibility
A project is operationally feasible if it appears that the solution can be operated by the participants
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Definition
Technical Feasibility
A project is technically feasible if it appears that the solution is possible with today’s technology
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Definition
Organizational Feasibility
A project is organizationally feasible if it appears that the solution is political doable within the organization
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Definition
Environmental Feasibility
A project is environmentally feasible if it appears that the solution is not harmful to the environment
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Definition
Temporal Feasibility
A project is temporally feasible if it appears that the solution can be created in time
This is one that can make or break a lot of systems
Remember Time Boxing
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Definition
Time BoxingPlacing a due date for each deliverable from two weeks to two months
It is much easier to complete a small goal rather than a large one
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Definition
MeasurabilityMust overcome the ‘Productivity Paradox’.
Must explain the ‘Increasing Returns Model’
The user must be able to judge that the goal was met
This means the goal should be expressed in quantitative terms
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Definition
Measurability continued
For example A video can be rented in less than 15 seconds The fine was computed correctly A minimum wage employee with less than two
hours of training can learn to use the point of sale terminal
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Definition
ConstraintA limit on the system
For example Budget for project is $20,000.00 Must be completed in six months Must be usable by a minimum wage employee Must provide for changes in sales tax laws
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Definition
A soft constraint is set by an internal entityThis means that your organization can change themFor example Must be usable by a minimum wage employee Budget for project is $20,000.00 Some existing business rules may have to be
changed
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Definition
EventAn occurrence by an initiating actor that a system responds to
Sometimes called an external event as it is generated outside the system
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Definition
Environmental DiagramShows actors system participants events
and how they interact
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Definition
Environmental Diagram
Rent Video
PayEmployeesVideo Store
Information System
Clerk
Customer
Payroll Clerk
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Definition
Use CaseA narrative description of a system process initiated by an external event
Consists of actor actions and system responses for each individual step
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Definition
Use CaseSelect 4 or 5 High-Level Use Cases. Brief elaboration of these.
Prioritize Use Cases.
Can use ‘Scoring Method’ to Prioritize
Focus on 2 Expanded, Full-Dress Use Cases
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Definition
System EventThe Actor actions for each individual step
They consist of: typing in text boxes selecting from list boxes pushing buttons of forms
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Definition
System ResponseThe specific System Response for each system event
For example: Display price Print Receipt Post transaction to journal
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Deliverables
2. List system functions and attributes
For example record sale or Record sale in less than ten seconds Record sale using a web page
May be hidden such as Post transaction to journal
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Deliverables
3. Use case definitions
The use case is identified
Include its name
Include initiating and participation actors
Overview A customer arrives at a POS terminal with good to
purchase. The cashier records the purchase and the customer leaves with the goods upon completion
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Deliverables
PrototypePurpose is to show screens that user will be working with
Probably will not have much functionality
Possibly done in Visual Basic
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Deliverables
Draft Conceptual Model
Is just of list of each domain (business) object
For example: Customer Store Product
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Deliverables
Draft of Possible System Architecture
This is related to feasibility
Hardware costs and performance let decision makers know if system is feasible
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Summary
UML provides a standard for the following artifacts:
Project Specifications
Environmental Diagram
System functions & attributes
High level Use Cases
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Summary
Artifacts (cont’d)
Expanded Use Cases (top of page 67)
Typical Course of Events and System Response Table (pages 67-70)
Draft conceptual model