Transcript Decision Support Systems

Decision supports Systems Components
• Data management function
– Data warehouse
• Model management function
– Analytical models:
• Statistical model, management science model
• User interface
– Data visualization
New Developments in Decision
Support Systems
• Data visualization: Representing data in
graphical/multimedia formats for analysis.
– Web-based “dashboards”
• http://www.corda.com/centerview-executivedashboard-product-tour.php,
– Product tour
– Retail sales
• Data warehousing
• What-if scenarios
Data Warehouse
• A subject-oriented, integrated, time-variant,
non-updatable collection of data used in
support of management decision-making
processes
– Subject-oriented: e.g. customers, employees,
locations, products, time periods, etc.
• Dimensions for data analysis
– Integrated: Consistent naming conventions,
formats, encoding structures; from multiple data
sources
– Time-variant: Can study trends and changes
– Nonupdatable: Read-only, periodically refreshed
Data Warehouse Design
- Star Schema • Fact table
– contain detailed business data
• Ex. Line items of orders to compute total sales by
product, by salesperson.
• Dimension tables
– contain descriptions about the subjects of the
business such as customers, employees,
locations, products, time periods, etc.
The ETL Process
L
T
One,
companywide
warehouse
E
Periodic extraction  data is not completely current in warehouse
The ETL Process
• Capture/Extract
• Transform
–Scrub or data cleansing
• Load and Index
ETL = Extract, transform, and load
Example:
Order Processing System
CID
Cname
City
OID
ODate
Rating
SalesPerson
Customer
1
Has
M
Order
M
Qty
Has
M
Product
Price
PID
Pname
Star Schema
Location
Dimension
LocationCode
State
City
Can group by State, City
Product
Category
CategoryID
Description
FactTable
LocationCode
PeriodCode
Rating
PID
Qty
Amount
Product
Dimension
PID
Pname
CategoryID
CustomerRating
Dimension
Rating
Description
Period
Dimension
PeriodCode
Year
Quarter
From SalesDB to
MyDataWarehouse
• Extract data from SalesDB:
– Create query to get the data
– Download to MyDataWareHouse
• File/Import/Save as Table
• Transform:
– Transform City to Location
– Transform Odate to Period
• Query FactPC
• Load data to FactTable
On-Line Analytical Processing (OLAP) Tools
• The use of a set of graphical tools that provides
users with multidimensional views of their data
and allows them to analyze the data using simple
windowing techniques
• Relational OLAP (ROLAP)
– Traditional relational representation
• Multidimensional OLAP (MOLAP)
– Cube structure
• OLAP Operations
– Cube slicing–come up with 2-D view of data
– Drill-down–going from summary to more detailed
views
– Roll-up – the opposite direction of drill-down
– Reaggregation – rearrange the order of dimensions
Slicing a data cube
Summary report
Example of drill-down
Starting with summary
data, users can obtain
details for particular
cells
Drill-down with
color added
Geological Information System
GIS
• GIS is a computer-based tool for mapping and
analyzing things that exist and events that
happen on earth. GIS technology integrates
common database operations such as query
and statistical analysis with the unique
visualization and geographic analysis benefits
offered by maps.
Data of GIS
• Geodatabase:
– A geodatabase is a database that is in some
way referenced to locations on the earth.
• Longitude, latitude
• Attribute data:
– Attribute data generally defined as additional
information, which can then be tied to spatial
data.
• Example: Google Earth
Scenario
• A scenario is an assumption about input
variables.
• Excel’s Scenarios is a what-if-analysis tool. A
scenario is a set of values that Microsoft Excel
saves and can substitute automatically in your
worksheet.
• You can use scenarios to forecast the outcome
of a worksheet model. You can create and save
different groups of values on a worksheet and
then switch to any of these new scenarios to
view different results.
Creating a Scenario
• Tools/Scenarios
– Add scenario
• Changing cells
• Resulting cells
• Demo: benefit.xls
Chart
Charting Decision Rules
• An Internet Service Provider charges
customers based on hours used:
– First 10 hours
– Each of the next 20 hours
– Hours over 30 hours
$15
$2 per hour
$1 per hour
Comparing Decision Rules
• Plan 2:
– First 20 hours:
– Hours over 20
$20
$1.5
• Plan 3:
– $35 unlimited access.
Charting Functions
• Demand function:
– P = 150 – 6*Q^2
• Supply function:
– P = 10* Q^2 + 2*Q
• Note:
– Positive area
– Value axis maximum/minimum value:
• Format Value Axis