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Spring 2011 - ÇG IE398 - lecture 2 1
lecture 2 : the problem situation
we discuss:
• the components of a problem situation
• mind maps• rich pictures
Spring 2011 - ÇG IE398 - lecture 2 2
Spring 2011 - ÇG IE398 - lecture 2 3
components of a problem • issues and problems that are the subject of inquiry occur within a context that we call the “problem situation”
(the context is that part of a system's environment that can neither be influenced nor
controlled)• involved in each problem situation, are
–decision makers– objectives– decision criterion– performance measure– control inputs or courses of action
• we can make these more clear as follows
Spring 2011 - ÇG IE398 - lecture 2 4
• goal indicates overall purposee.g. setting up an ambulance service
• objective is more specific than a goale.g. finding the best location for an ambulance service(the textbook makes no distinction between a goal and an objective)
• decision criterion: a rule by which we judge the
achievement of an objectivee.g. maximising expected profits or the rate of return on
investments; minimising total distance travelled, or the longest distance travelled etc.
• performance measure: an output that serves to measure system performance
• objective function: mathematical expression of performance measure, expressing o/p as a function of control i/p’s, (decision variables)
Spring 2011 - ÇG IE398 - lecture 2 5
• stakeholders (roles assumed with respect to the narrow system of interest):– problem owners who have control over
some aspects of the problem situation, such as choosing a course of action
– problem users who use the “solution”, ie. implement the decisions of problem owners
– problem customers, the affected beneficiaries or victims of the solution to be implemented
– analysts (e.g. the OR analyst or the IE) address the problem and develop a solution that must be approved by peroblem owners
• role definition is important; e.g. consider the case of screening for breast cancer:– if the Health Minister initiates the project,
concern will be about effective allocation of funds, priorities, trade-offs, costs; the entire health system will be the of interest
– if doctors or women’s groups initiate the project, concern will be about minimising incidence of cancer and fatalities, not directly over costs
– users may need to be persuaded and trained lest they sabotage implementation
– roles may need to be reassigned for efficiency or efficacy
Spring 2011 - ÇG IE398 - lecture 2 6
Spring 2011 - ÇG IE398 - lecture 2 7
mind maps and rich pictures
these are useful as a first step in setting down and representing our perception of the problem situation where:
•all aspects of a problem situation are mapped on a free-style diagram with or without pictures
•including as much or as little detail as necessary•independently of any particular W (ie. world view) but as a joint product of conflicting views of the situation
•without trying to identify any systems as yet•redrawn as many times as needed in the course of the project
Spring 2011 - ÇG IE398 - lecture 2 8
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Spring 2011 - ÇG IE398 - lecture 2 10
these diagrams should show:• elements of structure; stable or slow-
changing aspects such as buildings, equipment, products, rules, advantages, difficulties etc.
• elements of process; dynamic aspects that change fast such as activities, material flows, information etc.
• relationships between structure and process and consequences of these relationships
• soft as well as hard facts• multiple aspects to facilitate learning and
discussion• not too many connectors, precedences or flows
Spring 2011 - ÇG 11IE398 - lecture 2
Spring 2011 - ÇG 12IE398 - lecture 2