1 Chapter 4 Modeling Basic Operations & Inputs.

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Chapter 4

Modeling Basic Operations & Inputs

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OutlineOutline

detailed operations Model 04-01 Model 04-02 Model 04-03 Model 04-04

general usage of ARENA

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A Sequence of Related ModelsA Sequence of Related Models

Model 4-1: a sealed electronic assembly and test system more features,

Model 4-2: additional features in scheduling, failure, and states of resources

Model 4-3: more advanced animation Model 4-4: advanced features in moving –

stations, routes, and animation

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An Electronic Assembly/Test SystemAn Electronic Assembly/Test System

Sealer

Part A

EXPO(5)

Part B

Batches of 4 EXPO(30), de-batch on arrival

Process A

Tria(1,4,8)

Process B

Tria(3,5,10)

Part A TRIA(1,3,4)

Part B WEIB (2.5, 5.3) EXPO(45)

Rework

9%

91%

Shipped

20%Scrapped

80%Salvaged &

Shipped

5


Sealer

Part A

EXPO(5)Process A

Tria(1,4,8)

Process B

Tria(3,5,10)

Part A TRIA(1,3,4)

Part B WEIB (2.5, 5.3) EXPO(45)

Rework

9%

91%

Shipped

20%Scrapped

80%Salvaged &

Shipped

Part B

Batches of 4 EXPO(30), de-batch on arrival


type-dependent service timescreate entities

processeschance

statistics

unreliable system

to determine the number of rackscreate batches of 4 entities & de-batch later

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Model 04-01Model 04-01

ignore details the 2-minute traveling times the working hours of stations schedule of the re-workers failure of the sealer the number of racks used

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Remarks for Model 04-01Remarks for Model 04-01

two types of entities entity-dependent service time: an attributes of

an entity: a local variable of the entity time in system: marking the time entering the

system chance: conditional routes type dependent statistics: record mechanism

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Model 04.02

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New Features of Model 04-02: New Features of Model 04-02: Refinements of Model 04-01Refinements of Model 04-01

run length 10 days, 16 hours per day

two 8 hr shifts / day 1 re-worker in the first shift

2 re-workers in the second shift

sealer may break down life time expo(120)

repair time expo(4)

statistics of the status of sealer: on and off

statistics of the rework queue (distribution of # of racks) each rack possible to hold 10 items

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Schedule of the Rework StationSchedule of the Rework Station

run length: Setup menu variable resource

define schedule of re-workers (Schedule module) modify the # of hours per day to suit the schedule

associate the schedule with the (resource of the) re-work station

option on resource when a service is interrupted: ignore, wait, preempt

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Failure of ResourceFailure of Resource

failure of the sealer define a failure (Failure module in Advanced

Processes) associate the failure with a resource the treatment of incomplete work at a failure

same as schedule: ignore, wait, and preempt

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Collect StatisticsCollect Statistics

statistics time in system: customer average

sealer: state dependent, time average

rack: number of rack needed, time average

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Collect StatisticsCollect Statistics

to get time-in-system statistics of a type of entities

(customer-average statistics) use Record module

record exit time - creation time

compile statistics

to get time-persistent statistics of a collection of values of

variables or a collection of states of resources use Statistics module (in Advance Process Template)

may need to self-define categories

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Statistics for Racks and for SealersStatistics for Racks and for Sealers

time-persistent statistics – Statistic module statistics on sealer status

fraction of idle, failed, and busy time of sealer statistic type: frequency (not time-persistent)

statistics on number of racks needed fractions of time for different number of racks used statistic type: frequency (not time-persistent)

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Instantaneous Utilization Instantaneous Utilization and Scheduled Utilizationand Scheduled Utilization

for a resource, let B(t) = # of units of the resource busy at t M(t) = # of units of the resource available at t

instantaneous utilization

scheduled utilization

T

dsTsMsB

0 )()(

0 0

0 0

( ) / ( )

( ) / ( )

T T

T T

B s Tds B s ds

M s Tds M s ds

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Model 04.03

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animation of queues length and points of queues

changing entity pictures creating new one: copy, edit, and assign entity

picture adding resource pictures

creating resource picture from animation tool bar adding variable plots

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Model 04.04

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saving connection links by station and route modules stations: module for program and icon for animation

route: module for program and link for animation

possible to have multiple station icons in animation for one

location

two station icons between one route link in animation

changing an entity picture: by an Assignment

Module

1 Chapter 4 Modeling Basic Operations & Inputs.

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