Session 07 Problem Identification and Solving Problem Identification and Solving Chapter 6 Overview Learning objectives 1 What is a problem 2 Structure and complexity in problems 3 Puzzles problems and messes ID: 311176
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Slide1
Principles of Information Systems
Session
07
Problem Identification and SolvingSlide2
Problem Identification and Solving
Chapter
6Slide3
OverviewLearning objectives
1. What is a problem?
2. Structure and complexity in problems
3. Puzzles, problems and messes
4. General methods for solving problems
5. From problems to solutions
6. Creative problem solving strategies
7. SummarySlide4
Learning objectives
Identify different kinds of problems and approaches to their solution
Distinguish problems, symptoms and problem situations
Explain the difference between puzzles, problems and messes
Apply the various problem-solving methods in appropriate solutions
Recognize wicked, intractable and insoluble problems
Describe some techniques for creative problem solvingSlide5
What is a problem? Examples for people, organisations, society
Problem or symptom?
Irritant or sign e.g. Ibises in suburbs –nuisance or sign of drought
Problem analysis - an important skill
1. What is a problem?
2. Structure and complexity
3. Puzzles, problems and messes
4. General methods
5. From problems to solutions
6. Creative problem solving strategies
7. SummarySlide6
Identifying the real problemDistinguishing symptoms from deeper problems
tingling hands may seem a trivial problem but may be a symptom of a stroke or diabetes
high staff turnover may lead to extra recruitment and training costs. Underlying problem may be low morale and people are leaving because of bad managers
Problem analysis aims at finding deeper problems that underlie or cause an apparent problem.Slide7
Problem situationsCan be a set (or system) of related problemsLosing your job
Can
’
t pay for house
Partner leaves youStress from all this …
Which do you fix first?Slide8
Problems
Givens
:
what you have at the start
Operations
:
what you can do with what you have
Goals
:
what you are trying to achieve
I’m Winston Wolf, I solve problems.Jimmie: Good, ‘cause we got one.
(Wayne
Wickelgren
)Slide9
Given: and Operation: Insert a vowelGoal: Make a complete English wordGiven:
Operations
: arithmetic
Goal
: Combine to make 20
Examples
3
4
2
S _ C K
A
E
I
O
U
+
/
x
-Slide10
Example: Bagh Chalhttp://en.wikipedia.org/wiki/Bagh_ChalSlide11
Example
Given:
an incomplete chessboard and 31 dominos
Operation
: place dominos on board
Goal
: until board is covered Slide12
Problem analysisWickelgren
’
s idea applies widely:
puzzles … organisational strategy … warfare…
Analysis involves:
identifying components and regularities
whether there is enough information
Some problems are
intractable
:
(not easily controlled or directed; not docile or manageable; stubborn; obstinate.)
They need other types of approach for a solutionProblems worthy of attackProve their worth by hitting backSlide13
Problems can range from simple puzzles to complex and messy situations.
Problem analysis and problem identification are important skills.
All problems have
givens
,
operations
and
goals
RecapSlide14
Structure and complexity
Amount of
formal structure
the more structure a problem has, the easier is a generalised solution.
Amount of
complexity
more complex problems are less
tractable
1. What is a problem?
2. Structure and complexity
3. Puzzles, problems and messes
4. General methods
5. From problems to solutions
6. Creative problem solving strategies
7. SummarySlide15
Structure - examples Abdul is older than Bob
Bob is older than Christine
age is structured (transitive)
Equivalently
Abdul is taller than Bob
Bob is taller than Christine
“
who is tallest
”
has same structure
A B CSlide16
Problem: Where does John live?
John, Val and
Diarmuid
all live
in the Perth area
Val lives northeast of John
Meeting at
Diarmuid
’
s house is most convenientSlide17
Degrees of structureStructured problems
: routine, readily solved with known methods. Suited to computer analysis.
Semi-structured problems
: part of the problem is structured. This part may be solved in a familiar way, then can support judgement
Unstructured problems:
no ready method of solution, may need to be structured somehow for solving or management. Slide18
ExamplesStructured problem – sudoku
Semi-structured
problem
Choosing which car to buy within your budget
Unstructured
problem –
should we build a dam?Slide19
ComplexityHow many things are involved?
How do they interact?
Do they get messier over time?
Are they combined with other problems in the wider situation?
Problem structuring can help reduce complexity.Slide20
Three levels of complexityPuzzles
:
well-defined whose fixed solution is readily worked out.
(e.g Sudoku, FreeCell).
Problems
:
well defined, but different exclusive solutions are possible.
(e.g choosing a home computer, designing your garden)
Messes
: complex issues, not well defined, or without agreed problem definition.
(e.g. dams, bypasses)
. Solutions must address the whole mess: ignoring relationships to other parts of the mess will lead to failure.
(Ackoff)Slide21
Dragon Curve by
Solkoll
with extract
Structure
and
Complexity
are similarSlide22
Structure and complexity help define problems.
The more
structure
a problem has, the easier is a generalised solution.
More
complex
problems are less tractable.
RecapSlide23
Puzzles, problems & messes
Puzzles
Problems
Constraint problems
Optimisation, maximisation and minimisation problems
Search space and NP-completeness
Messes
What
is a problem?
Structure
and complexity
Puzzles
, problems and messesGeneral methods From problems to solutions
Creative
problem solving strategies
SummarySlide24
1. Puzzles
Simple problems, commonly quantifiable or logical, with well understood methods
What discount applies for cash now, rather than over a three-year term?
How much feed to maintain yield from a stock of cattle? How many animals should I graze on this land to maximise productivity?
Discipline-specific methods/formulae apply.
F = C/5 * 9 + 32 given 100°C – what is Fahrenheit?
Solution usually unambiguous: exact numbers. Slide25
2. ProblemsSome quantification, but also unknowns. (semi-structured).
How many prisons/hospitals should we have?
What export price to allow for tariffs and legal compliance costs in unpredictable market?
How much should I spend on marketing, compared with research and development?
Possible approach:
Identify assumptions, work out a numerical answer, then consider wider feasibility. Slide26
How many hospitals?
Work out the
population
to be served by the hospitals, the average
percentage
in hospital at any one time, and their
average
stay.
Other information shows that:
The population is expanding
people are living longer
health problems increasingly manageable at home
a policy trend towards keeping people out of hospital where possible.
Assumptions moderate original number up or down. Answers more approximate than exact.Slide27
A general class: Constraint- satisfaction problems
Set limits on what solutions are possible
May be quantifiable or qualitative in nature.
e.g. Decision problems with two alternatives or many
Where to place the next O
Where should my family live?
How should I vote?
Some have no right answer, or many equally good or bad answers. Slide28
Where should my family live?
Answers are needed! Often
satisfactory
answers are found by
constraining
the problem. House locations may be narrowed down by asking:
Can I get to my place of livelihood from there?
Can the children get
to a good
school?
Is it in an attractive area
Is transport convenient?
Can I afford it?Does the whole family like it?Is it near the CBD?Can I get broadband? … Slide29
Hard vs soft constraints
Such considerations constrain, but don
’
t determine the solution.
Hard
constraints are not negotiable
I must be able to get to my work place
F = C/5 * 9 + 32
Soft
allow some tolerance
proximity to the beach is debatable or can be relaxed (i.e. loosened or dropped). Typical solution may not meet all constraints but it may meet enough of them well enough. Not perfect but satisfies the requirements.Slide30
Optimisation, maximisation and minimisation problems
Examples:
How to maximise shareholder value?
How to minimise staff turnover?
Optimal mix of products we should manufacture?
Optimal density of planting for best yield?
Stacking shipping containers at ports.
Stacking containers is an
optimisation
problem. Find a balance between putting through as many containers as possible to
maximise
profit, and
minimising
the throughput time to remain competitive. Tools e.g. MS SolverSlide31
Search space problems
When many components interact this creates a very large set of possibilities. Perhaps only one combination is of interest.
Sudoku
Travelling
sales rep
problem.
Which way should the travelling
sales rep
go?
Computational complexity:
Brute force
search may take forever, need more intelligent solution strategies.Slide32
3. Messes
Puzzles and problems can be
tamed
. They apply in idealised worlds, without social and political realities. But consider:
Should this country have the death penalty?
How should we deal with poverty?
How can we fix the university parking crisis?
Messes need
managing
not solving
deal with the situation vs solve the problem
Problem and possible solutions (may) be defined, but method to reach solution is arguable. Some messes are wicked problems.Slide33
How can we fix the
parking
crisis? Slide34
Puzzles
,
problems
and
messes
are three classes of problems
.
Each has particular qualities and general approaches to solution which can be used.
RecapSlide35
General methods for solving problems
Pólya
’
s 4-step general method
Understand the problem 2. Devise a plan
Implement the plan 4.
Reflect on the outcome
Within each steps are prompts:
- have you seen this before? - Solve a simpler problem.
Pólya
called these
heuristics
. They help you guess at or partly solve a more complex problem. 1. What is a problem?2. Structure and complexity3. Puzzles, problems and messes
4. General methods
5. From problems to solutions
6. Creative problem solving
strategies
7. SummarySlide36
Heuristic:
Solve a simpler problem
Sliding tiles puzzleSlide37
Herbert Simon’s model
Closely related to
“
scientific method
”
but tailored to management decision problems
Intelligence
: collect information, identify the problem
Design
: conceive alternatives, select criteria
Choice
: evaluate alternatives, select
Implementation
: put decision into effect, allocate resources, controlBasis for other methods and versionsSlide38
There are some general approaches that can be applied to all problems,
e.g. Pólya's method and Simon
’
s model
RecapSlide39
From problems to solutions
Generally all aim at
understanding and defining the problem
designing a solution addressing a specifically defined problem.
5.1 Facets of problem definition
5.2 Approaches to problem solution
Puzzles
Problems
Messes and wicked problems
1. What is a problem?
2. Structure and complexity
3. Puzzles, problems and messes
4. General methods 5. From problems to solutions6. Creative problem solving
strategies
7. SummarySlide40
problem definition
Formulating
problems: how a problem is described and represented makes it easier or harder to handle. Try these:
19+27+46+54+73+81= (1)
19+81+54+46+73+27= (2)
7x6x5x4x3x2x1 = (3)
1x2x3x4x5x6x7 = (4)
These pairs have equivalent intellectual difficulty but (2) and (4) are easier.
A problem well stated is half solved
Slide41
Problem OwnershipWho has the parking problem? Students /staff who can’t park?
University officers?
Bus company?
Government?
Solutions can cause problems!
A rail link may affect nearby houses
Multi-storey stops library expansion…Slide42
Practice example: (from Gause & Weinberg)
A road tunnel through the Swiss Alps has been built. For safety a sign is made:
At a scenic viewpoint just beyond the far end of the tunnel people stop for photos and refreshment. Many then find their car batteries dead from leaving lights on!
National police
are fed up jump-starting cars. Tourists are upset.
WHOSE PROBLEM IS IT?
Tunnel ahead - please turn on headlightsSlide43
WHOSE PROBLEM IS IT?Drivers
Tunnel engineer
Gendarmes
Swiss canton president
Other
All of the above
None of the above
Probably the
tunnel engineer
’
s
problem
WHAT SOLUTIONS MIGHT WORK? Slide44
Possible solutionsSign at tunnel end?
Ignore it?
Battery chargers at rest stop?
Franchise battery charging?
Each solution causes new problems!
Turn off your lightsSlide45
Possible solutionsSign at tunnel end?Problem: people
should not turn
off lights at night
Ignore it?
Problem: no changes and loss of reputation
Battery chargers at rest stop?
Problem: expensive, maintenance, unpopular…
Franchise battery charging?
Problem: commercialises rest stop, unacceptable to tourists, govt. …
A better sign?
Turn off your lightsSlide46
A better sign?
If
it is daylight and
if
your lights are on
then
turn off your lights
If
it is dark and
if
your lights are off
then
turn on your lightsIf it is daylight and if your lights are off then leave your lights off If it is dark and if your lights are on then leave your lights on
Turn off your lightsSlide47Slide48Slide49
Choosing which problem to solve
Which problem to solve in a problem situation?
analysing specific problem components
prioritising and scoping
Medical triage at an accident. Who to treat first with the limited resources of ambulance officers and time?
An organisation identifies problems in its marketing, finance, IT, and innovation departments. Business analysis suggests fixing the IT aspects is most critical.Slide50
Agreed conceptual modelsWith (19+81)+(54+46)+(73+27)=
all information is given, operations and goal are obvious
Problem is understood so the solution is straightforward.
The
conceptual model
is base 10 arithmetic
Not always so clear e.g. in ethical questions. Slide51
Accountancy
puzzle
A trading company has this information for June:
a. sales revenues
=
$ 150 000
b. product costs of goods sold = $
80
000
c. purchasing costs
=
$
5 000d. overhead costs = $ 30 000 1. Compute the gross margin in June;2. Compute the operating income in June.Arithmetic is straightforward, but conceptual model may be disputed. Different ways to calculate Product costs (w.r.t selling price, or yearly income statement)
Different interpretation
different result.Slide52
Approaches to problem solution
Puzzles have structure that may be used in defining more complex problems.
e.g.Sudoku
is a constraint satisfaction problem:
Simple rules
Universally played
Develops thinking skills
Only logic required
Kids stuff
Unique solutionSlide53
Real problems also need insight into the worldHow much wine should I provide for a party?
At what rate should I repay my home loan?
These (numerical) everyday life problems differ from maths puzzles, and use heuristics
Allow one glass/hour over four hours each, and assume one case produces 60 glasses
(Pólya)
Guess likely answer and check - Work backwards
Draw a figure - Solve a related problem
Problems Slide54
SEND
+
MORE
MONEY
DONALD
+
GERALD
ROBERT
Crypt-arithmetic and
FreecellSlide55
Practice problem
A rock climber sets off at first light to ascend a cliff-face. Taking all day, pausing at various tricky bits, he spends the night at the top. He starts climbing down at the same time the next morning. How can we prove that there must be a point on the cliff that will be passed at the same time of day, no matter how much more quickly he descends?Slide56
a diagram may be the best representation
step
xSlide57
Messes
Soft Systems Methodology (SSM)
Strategic
Options Development and Analysis (SODA)
Strategic Choice Analysis (SCA)
Morphological analysis
The Viable Systems Model (see chapter 8)
Scenario analysis
Simulation of situations using system dynamics
Slide58
Soft Systems Methodology (SSM) Originated by Peter Checkland (1981)
‘
Systems Thinking, Systems Practice
’
Focuses on the
human
activity aspects and social and political contexts of a problem
Provides guidance in defining complex problems thoroughly and identifying feasible and desirable solutions
Rich pictures (chapter 3) are used widely in SSMSlide59
Strategic Options Development and Analysis (SODA)
Developed by Colin Eden and Fran Ackerman
A version of cognitive mapping directly designed to address
organisational
problems
An unstructured situation is organised into a structure that surfaces understanding
Identifies relevant issues which are then clustered and linked
Issues can then be dealt with in agreed action plans
A shared map is produced
A SODA map represents how problem owners and team members think through their decision making in messy situationsSlide60
Strategic Choice Analysis (SCA)
John Friend and Alan Hickling
Group planning decisions
Targets situations where there are complex interconnections, lack of structure and uncertainty
Recognises different sources of knowledge contribution, and forces a practicable level of consensus and learning
Has been used in developing countries and by humanitarian organisations in disaster reliefSlide61
Morphological analysis
Fritz Zwicky
Deals with structure in messes
Recognises that judgemental processes are involved
Identifies the
‘
shape
’
of the problem space and how the parts interact
Emphasises coherence and consistency, rather than quantification and causality
Has been used in many organisations to invent and innovateSlide62
Once a problem has been understood and defined, appropriate methods of solution come into play.
Puzzles, problems and messes have different approaches to problem solving.
RecapSlide63
Creative problem solving strategies
Avoid dealing head-on with the problem!
Reframe it
Examine its assumptions
Solve another problemRefer it to someone elseAsk around
Procrastinate appropriately
Go around blockages
Sleep on it
What
is a problem?
Structure
and complexity
Puzzles
, problems and messesGeneral methods From problems to solutions
Creative
problem solving strategies
SummarySlide64
The old nine dots puzzle
Without lifting your pen from the paper, draw four straight lines that cross through all the dots.
2. If that is too easy, try this. Draw one straight line through all nine dots.
?Slide65
Over-constraining or
limiting the problem
J. AdamsSlide66
Conceptual Blockbusting (Adams)
Perceptual
blocks
Seeing what you expect to see
Emotional
blocks
Fear of taking a risk
Cultural
and environmental blocks
Tradition is better than change
Reason is good, intuition is bad
Intellectual blocks using the wrong language (e.g. verbal vs. visual)Slide67
Exercise (optional)
Table tennis ball inside a steel pipe buried in concrete
Six of you have:
30m clothesline hammer
Chisel box of cereal
File wire coat hanger
Monkey wrench light bulb
Think of ways to get ball out of pipe. (5 mins)
(Adams, p54)Slide68
Lateral Thinking (Edward de Bono)
Digging a hole deeper is useless if it
’
s in the wrong place
So reframe the problem
At a tennis tournament, there are 131 players in the men
’
s singles. How many matches were required to decide the winner?
“
A truck is stuck under a bridge. How to get it out?Slide69
What is this?
?Slide70
What is this?Slide71
Oblique Strategies (Eno, Schmidt)
Turn
it upside down
Make
an exhaustive list of everything you might do & do the last thing on the list
Disconnect
from desire
Don
’
t
be afraid of things because they're easy to do
Is
there something missing
Do nothing for as long as possible Tidy up Do the words need changing? …Slide72
Malouff’s problem understanding strategies
1. Clarify the problem
2. Identify key elements of the problem
3. Visualize the problem or a relevant process or situation
4. Draw a picture of the problem or relevant process
5. Create a model of the problem or a relevant process
6. Imagine being the problem, a key process, or the solution
7. Simulate or act out a key problem element
8. Consider a specific example
9. Consider extreme case
10. Change perspective
11. Consider levels and systems Slide73
Creating problem solving strategies aim at freeing the
‘
blocks
’
to a solution,
e.g. by side-stepping, reframing, or examining their assumptions
RecapSlide74
Summary
“
Problems
”
are very common
All problems have givens, operations and goals
Puzzles/problems/messes can be classified by degree of structure and complexity
General approaches to problem identification and problem solving exist.
There are some systematic types of solution:
breaking problems down, using heuristics, reframing or creatively managing.
Messes require more advanced techniquesSlide75