120 likes | 242 Views
IE 429 Discrete Systems Simulation. Group 8: Extra Credit Example 5: Expression Geoffrey Cheung Chris Guzman Chris Mui. Expressions.
E N D
IE 429Discrete Systems Simulation Group 8: Extra Credit Example 5: Expression Geoffrey Cheung Chris Guzman Chris Mui
Expressions • An expression element is an element whose value is determined by referencing the expression name while the general term expression refers to a data type that defines the acceptable entries for a particular field.
Purpose of Expression • We use the expression module for travel time when travel time is consistent throughout the process to help aid when doing a sensitivity analysis. • The analyst would only have to change one expression element as oppose to many within the system. • When there are many processes with travel times that are the same (e.g. travel time of expo(3) or expo(4)) then analyst will only need to refer to the expression element within the process.
Practice Example • Part A arrives to the facility one by one with time between arrivals that are distributed exponentially with an average of 5 hours. • Part A goes through 4 different processes: welding (EXPO 5 hours), machining (EXPO 2 hours), paint (EXPO 3 hours), and inspection (EXPO 2 hours). • There is a travel time that is triangularly distributed with a minimum of .5 hours, maximum of 1.5 hours, and a mode of 1 hour before each process. • After the processes are completed, part A is sent to the warehouse. Run this model for 2000 hours.
Results – Tally Variables • Identifier Average Half Width Minimum Maximum Obs. • ___________________________________________________________________________________________________ • PartA.VATime 15.948 .76470 5.4401 38.227 405 • PartA.NVATime .00000 .00000 .00000 .00000 405 • PartA.WaitTime 103.60 (Corr) .00000 243.07 405 • PartA.TranTime .00000 .00000 .00000 .00000 405 • PartA.OtherTime .00000 .00000 .00000 .00000 405 • PartA.TotalTime 119.55 (Corr) 10.968 266.16 405 • Inspection.Queue.WaitTime 1.6834 .73676 .00000 16.145 405 • Machining.Queue.WaitTime 1.4772 .58827 .00000 17.815 408 • Paint.Queue.WaitTime 6.2826 3.6648 .00000 59.525 407 • Welding.Queue.WaitTime 95.265 (Corr) .00000 228.14 412
Results – Discrete Change Variables • Identifier Average Half Width Minimum Maximum FinalValue • _________________________________________________________________________________________________ • PartA.WIP 26.444 (Corr) .00000 56.000 46.000 • Inspector Gadget.NumberBusy .42360 .06710 .00000 1.0000 .00000 • Inspector Gadget.NumberScheduled 1.0000 (Insuf) 1.0000 1.0000 1.0000 • Inspector Gadget.Utilization .42360 .06710 .00000 1.0000 .00000 • Painter.NumberBusy .64789 (Insuf) .00000 1.0000 1.0000 • Painter.NumberScheduled 1.0000 (Insuf) 1.0000 1.0000 1.0000 • Painter.Utilization .64789 (Insuf) .00000 1.0000 1.0000 • Welder.NumberBusy .98944 (Insuf) .00000 1.0000 1.0000 • Welder.NumberScheduled 1.0000 (Insuf) 1.0000 1.0000 1.0000 • Welder.Utilization .98944 (Insuf) .00000 1.0000 1.0000
Results – Discrete Change Variables • Identifier Average Half Width Minimum Maximum FinalValue • _________________________________________________________________________________________________ • Worker.NumberBusy .39053 .06137 .00000 1.0000 1.0000 • Worker.NumberScheduled 1.0000 (Insuf) 1.0000 1.0000 1.0000 • Worker.Utilization .39053 .06137 .00000 1.0000 1.0000 • Inspection.Queue.NumberInQueue .34090 .16101 .00000 6.0000 .00000 • Machining.Queue.NumberInQueue .31169 (Insuf) .00000 8.0000 2.0000 • Paint.Queue.NumberInQueue 1.2785 .74172 .00000 14.000 .00000 • Welding.Queue.NumberInQueue 21.231 (Corr) .00000 53.000 39.000
Results - Outputs • Identifier Value • _____________________________________________________________ • PartA.NumberIn 451.00 • PartA.NumberOut 405.00 • Inspector Gadget.NumberSeized 405.00 • Inspector Gadget.ScheduledUtilization .42360 • Painter.NumberSeized 407.00 • Painter.ScheduledUtilization .64789 • Welder.NumberSeized 412.00 • Welder.ScheduledUtilization .98944 • Worker.NumberSeized 408.00 • Worker.ScheduledUtilization .39053 • System.NumberOut 405.00