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)

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• 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

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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

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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