1 Modeling workflows : The organizational dimension and alternative notations. Wil van der Aalst Eindhoven University of Technology Faculty of Technology Management Department of Information and Technology P.O. Box MB Eindhoven The Netherlands
2 Workflow management concepts A workflow definition is composed out of three parts: process definition: a description of the process itself resource classification: a classification of the resources to be used resource management rules: how to map work onto resources
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نکات مهم فصل سوم
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14 In what order? Pull control –Determined by people, i.e., a "race" for attention. –System may "suggest" urgent work items or offer multiple view on the work available. Push control –System decides whether the worker can view and/or select multiple work items, i.e., order may be enforced or suggested. In both cases possible queueing disciplines are: –FIFO (First In First Out) –LIFO (Last In First Out) –SPT (Shortest Processing Time) –EDD (Earliest Due Date) –PRIO (Prioritization based on case attributes)
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18 Example (taken from "Operations Management" by Roberta Russell & Bernard W. Taylor) PROCESSINGDUE WorkItemTIMEDATE A510 B1015 C25 D812 E68 Note that unlike most scheduling problems work items emerge on the fly!
19 FIFO (also known as FCFS) A B C D E FIFOSTARTPROCESSINGCOMPLETIONDUE SEQUENCETIMETIMETIMEDATETARDINESS
20 EDD C02250 E26880 A D B EDDSTARTPROCESSINGCOMPLETIONDUE SEQUENCETIMETIMETIMEDATETARDINESS
21 SPT C02250 A E D B SPTSTARTPROCESSINGCOMPLETIONDUE SEQUENCETIMETIMETIMEDATETARDINESS
22 Comparison FIFO FIFO EDD15.00 EDD SPT6.0 SPT AVERAGEAVERAGENO. OFMAXIMUM RULECOMPLETION TIMETARDINESSWI TARDYTARDINESS We will return to the topic of workflow analysis and simulation...
23 Push versus pull
24 Push control workflow enactment service push to a selected "victim"
25 Pull control workflow enactment service pull selected work items
26 pull control
27 Mosts WFM systems are hybrid, e.g., Staffware personal queue group queue
28 Who is doing what? Pull control –Determined by people, i.e., a "race" among resources. –Select to start and/or select to allocate work item. Push control –Round robin. –Weighted round robin. –Shortest queue. –Select the most specialized resource (i.e., do not allocate "generalists" unless needed).
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