information system
TRANSCRIPT
CHAPTER 10
How to describe an information system?
What Is A System?
What Is A System?
A system is an organized set of related components established to accomplish a certain task
Examples
Dig
estiv
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Sola
r Syste
m
Photo Source: http://www.solarviews.com/
Traffi
c Syste
m
Photo Source: http://pt.wikipedia.org/wiki/Ficheiro:Traffic_Light_German_Complex_With_Bicycles.JPG
Bu
siness sy
stem
s
Photo Source: http://www.flickr.com/photos/stuckincustoms/298010636/sizes/m/in/photostream/
Com
pu
ter sy
stem
Photo Source: http://www.apple.com/
What do they have in common?
Identifying the IPOS helps us understand how a system works
What is IPOS?
IPOS
INPUT - What goes in
PROCESS - What happens
inside?
OUTPUT - What comes out?
IPO
S
Computerized Payroll System
INPUT Smart card
PROCESS Process in the computer
OUTPUT Printout
How can we visually describe a system?
Ways of describing a system
1. Structure diagram Top down approach
2. Data flow diagrams
3. System flowcharts
Top Down Diagrams
An overall task is broken down into smaller more manageable task and the process goes on and on as needed.
What are the steps involved?
1. Identify the main tasks to be done and then break them down into smaller tasks
2. Read from top to bottom – each big task is broken down into smaller tasks.
3. Read it left to right tells you the order in which they happen
Main Tasks
Smaller Tasks
Computerized Payroll System
INPUT Smart card
PROCESS Process in the computer
OUTPUT Printout
Enter Data Edit Data Print Report
AutomaticData
captureEdit Delete Update
ChoosePeriodRange
Summary- Individual- Group
- Statistics
Printrecord
Compute employee’s salary
Example: Employee’s Salary
Collect patient data
Enter patient data
Print patient data
Give patient Data Capture
Form
Patient completes
Data Capture Form
LoadPatient
file
CreateNew
record
EnterNew
record
CheckPrinter
Forpaper
Printpreview
Printrecord
Create new patient record
Example: Patient Record
Data Flow Diagrams
A graphical representation of the "flow" of data through an information system, modelling its process aspects.
A DFD shows what kinds of data will be input to and output from the system, where the data will come from and go to, and where the data will be stored. (Source: Wikipedia)
Symbols
Rectangle (box)
The source of data - shows where the data has come fromExamples: order form,
application form
Part of the system which uses or consumes the data, called a sinkExamples: customer, student
Sausage or bubble
Used to denote a process performed on the data
A process is something which is done to the dataExamples: calculation, sorting
data, combining data etc.
Open Rectangle
It represents a data store
Shows where the data is stored – this include a manual store of a hard copy
Arrows
It shows how the other symbols are connected
Doctor’s appointmentCustomer data file
Produce list of patients overdue
for an appointment
Merge fields into Appointment
Reminder letter
Standard lettersFile (template)
Copy kept in filing cabinet
Payroll System
Employee data file
Produce SUMMARY of login and logout
for the month
Calculate salary/wage based on the
summary
Employee/Accounting fileIs updatedAnd stored
System Flowcharts
A flowchart is a type of diagram that represents an algorithm or process, showing the steps as boxes of various kinds, and their order by connecting these with arrows. This diagrammatic representation can give a step-by-step solution to a given problem. (Source: Wikipedia)
Payroll System – time in
START
Record found?
Displayerror message
Recordupdated
END
Y N
Swipe card
New PatientSTART
CompletedBy
patient
Error?
Input byreceptionist
Validation
Valid? Displayerror message
Visual check
on form
A
Patientfile
Mail merge
Data capture form
Welcomeletter to
new patientNew patient
standard welcome
letter
END
Y
N
A
N
Y
Now it’s your turn…
Make a flowchart of the following activities:
Prepare a cup of hot coffee Watch your favorite TV show Call a friend Starting the computer
Development Timeline
A Gantt chart is a type of bar chart that illustrates a project schedule. Gantt charts illustrate the start and finish dates of the terminal elements and summary elements of a project.
END