1. Modeling Basic Operations & Inputs
Chapter 4
Modeling Basic Operations & Inputs

2. Outline detailed operations general usage of ARENA Model 04-01

3. A 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

4. An Electronic Assembly/Test System
Part A
EXPO(5)
Scrapped
Process A
Tria(1,4,8)
Part A TRIA(1,3,4)
Part B WEIB (2.5, 5.3)
20%
Rework 9%
80%
EXPO(45)
Salvaged & Shipped
Sealer
91%
Shipped
Part B
Batches of 4 EXPO(30), de-batch on arrival
Process B
Tria(3,5,10)

5. An Electronic Assembly/Test System
create entities
statistics
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
processes
chance
type-dependent service times
unreliable system
create batches of 4 entities & de-batch later
to determine the number of racks

6. Model 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

7. Remarks 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

8. Model 04.02

9. New Features of Model 04-02: Refinements 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

10. Schedule 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

11. Failure 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

12. Collect Statistics statistics time in system: customer average
sealer: state dependent, time average
rack: number of rack needed, time average

13. Collect 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

14. Statistics 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

15. Instantaneous Utilization and 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

16. Model 04.03

17. New Features of Model 04-03: Refinements of Model 04-02
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

18. Model 04.04

19. New Features of Model 04-04: Refinements of Model 04-03
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