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Decision support and BI systems chapter 04

Decision Support and
Business Intelligence
Systems
(9th Ed., Prentice Hall)
Chapter 4:

Modeling and Analysis


Learning Objectives










4-2


Understand the basic concepts of
management support system (MSS) modeling
Describe how MSS models interact with data
and the users
Understand the well-known model classes and
decision making with a few alternatives
Describe how spreadsheets can be used for
MSS modeling and solution
Explain the basic concepts of optimization,
simulation and heuristics; when to use which

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Learning Objectives











4-3

Describe how to structure a linear
programming model
Understand how search methods are used to
solve MSS models
Explain the differences among algorithms,
blind search, and heuristics
Describe how to handle multiple goals
Explain what is meant by sensitivity analysis,
what-if analysis, and goal seeking
Describe the key issues of model management


Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Opening Vignette:
“Model-Based Auctions Serve More
Lunches in Chile”
 Background: problem situation
 Proposed solution
 Results
 Answer and discuss the case questions

4-4

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Modeling and Analysis Topics











4-5

Modeling for MSS (a critical component)
Static and dynamic models
Treating certainty, uncertainty, and risk
Influence diagrams (in the posted PDF file)
MSS modeling in spreadsheets
Decision analysis of a few alternatives (with
decision tables and decision trees)
Optimization via mathematical programming
Heuristic programming
Simulation
Model base management

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


MSS Modeling



A key element in most MSS
Leads to reduced cost and increased
revenue


DuPont Simulates Rail Transportation System
and Avoids Costly Capital Expenses



Procter & Gamble uses several DSS models
collectively to support strategic decisions



4-6

Locating distribution centers, assignment of DCs to
warehouses/customers, forecasting demand,
scheduling production per product type, etc.

Fiat, Pillowtex (…operational efficiency)…

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Major Modeling Issues




Problem identification and environmental
analysis (information collection)
Variable identification




Forecasting/predicting




4-7

More information leads to better prediction

Multiple models: A MSS can include several
models, each of which represents a
different part of the decision-making
problem




Influence diagrams, cognitive maps

Categories of models >>>

Model management

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Categories of Models
Category

4-8

Objective

Techniques

Optimization of
problems with few
alternatives

Find the best solution from Decision tables,
a small number of
decision trees
alternatives

Optimization via
algorithm

Find the best solution from
a large number of
alternatives using a stepby-step process

Linear and other
mathematical
programming
models

Optimization via
an analytic formula

Find the best solution in
one step using a formula

Some inventory
models

Simulation

Find a good enough
solution by experimenting
with a dynamic model of
the system

Several types of
simulation

Heuristics

Find a good enough
solution using “commonsense” rules

Heuristic
programming and
expert systems

Predictive
and
Predict future
Forecasting, Markov
Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall
other models
occurrences, what-if
chains, financial, …


Static and Dynamic Models


Static Analysis






Dynamic Analysis






4-9

Single snapshot of the situation
Single interval
Steady state
Dynamic models
Evaluate scenarios that change over time
Time dependent
Represents trends and patterns over time
More realistic: Extends static models

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Decision Making:
Treating Certainty, Uncertainty and
Risk
 Certainty Models






Uncertainty






Several outcomes for each decision
Probability of each outcome is unknown
Knowledge would lead to less uncertainty

Risk analysis (probabilistic decision making)




4-10

Assume complete knowledge
All potential outcomes are known
May yield optimal solution

Probability of each of several outcomes
occurring
Level of uncertainty => Risk (expected value)

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Certainty, Uncertainty and Risk

4-11

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Influence Diagrams
(Posted on the Course Website)







Graphical representations of a model
“Model of a model”
A tool for visual communication
Some influence diagram packages create and
solve the mathematical model
Framework for expressing MSS model
relationships
Rectangle = a decision variable
Circle = uncontrollable or intermediate variable
Oval = result (outcome) variable: intermediate or final
Variables are connected with arrows  indicates the
direction of influence (relationship)

4-12

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Influence Diagrams:
Relationships
CERTAINTY
Amount in
CDs

Interest
Collected

UNCERTAINTY
Price
Sales

The shape of
the arrow
indicates the
type of
relationship

RANDOM (risk) variable: Place a tilde (~) above the variable’s name
~
Demand
Sales
4-13

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Influence Diagrams: Example
An influence diagram for the profit model
Unit Price
~
Amount used in
Advertisement

Income
Units Sold
Profit

Profit = Income – Expense
Unit Cost
Income = UnitsSold * UnitPrice
UnitsSold = 0.5 * Advertisement Expense
Expenses = UnitsCost * UnitSold + FixedCost

Expenses

Fixed Cost

4-14

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Influence Diagrams: Software


Analytica, Lumina Decision Systems




DecisionPro, Vanguard Software Co.




Integrates influence diagrams and Excel, also supports
Monte Carlo simulations

PrecisionTree, Palisade Co.


4-15

Includes influence diagrams, decision trees and
simulation

Definitive Scenario, Definitive Software




Supports hierarchical (tree structured) diagrams

DATA Decision Analysis, TreeAge Software




Supports hierarchical (multi-level) diagrams

Creates influence diagrams and decision trees directly
in an Excel spreadsheet

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Analytica Influence Diagram of a
Marketing
Problem: The Marketing Model

4-16

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Analytica: The Price Submodel

4-17

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Analytica: The Sales Submodel

4-18

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


MSS Modeling with Spreadsheets





Spreadsheet: most popular end-user modeling
tool
Flexible and easy to use
Powerful functions









4-19

Add-in functions and solvers

Programmability (via macros)
What-if analysis
Goal seeking
Simple database management
Seamless integration of model and data
Incorporates both static and dynamic models
Examples: Microsoft Excel, Lotus 1-2-3

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Excel spreadsheet - static model example:
Simple loan calculation of monthly
payments

F = P(1 + i ) n
 i (1 + i ) n 
A = P

n
(
1
+
i
)

1



4-20

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Excel spreadsheet Dynamic model
example:
Simple loan
calculation of
monthly payments
and effects of
prepayment

4-21

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Decision Analysis: A Few
Alternatives
Single Goal Situations
Decision tables





Decision trees







4-22

Multiple criteria decision analysis
Features include decision
variables (alternatives),
uncontrollable variables, result
variables

Graphical representation of
relationships
Multiple criteria approach
Demonstrates complex
relationships
Cumbersome, if many
alternatives exists

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Decision Tables


Investment example



One goal: maximize the yield after one year



Yield depends on the status of the economy
(the state of nature)




4-23

Solid growth
Stagnation
Inflation

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Investment Example:
Possible Situations
1. If solid growth in the economy, bonds yield
12%; stocks 15%; time deposits 6.5%
2. If stagnation, bonds yield 6%; stocks 3%;
time deposits 6.5%
3. If inflation, bonds yield 3%; stocks lose 2%;
time deposits yield 6.5%

4-24

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


Investment Example:
Decision Table





4-25

Payoff Decision variables (alternatives)
Uncontrollable variables (states of economy)
Result variables (projected yield)
Tabular representation:

Copyright © 2011 Pearson Education, Inc. Publishing as Prentice Hall


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