Learning Simio Lab Series 1

Lab Module 01

Evaluating Potential Modifications to a Driver’s License Facility

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 1

Objectives and Outline

• Objectives

– Learn the basics of:

• The Simio user-interface

• Modeling in Simio

• Using the Simio Pivot Grid

• Outline

1.

Description of the system to be modeled

2.

Introduction to the Simio user interface

3.

Model the “current” configuration

4.

Experiment and verify the current model

5.

Model the “proposed” configuration

6.

In-lab and take-home assignments

Video 1

Video 2

Video 3

Video 4

Video 5

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 2

Applicants arrive at a rate of approximately

10/hour.

Performance Metrics:

• Server Utilizations

• Time In System

• Number In System

Drivers’ License Office

Check In

Written

Exam

At check-in, a single clerk checks the applicant’s

The written exam is administered by one of two exam clerks.

When an applicant driving history

(if any) and gives the applicant the initial paperwork.

arrives, s/he waits for an available clerk and, once one is available, takes the exam with the clerk.

Check-in takes approximately 5 minutes.

The exam requires approximately 8.8 minutes.

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved

Check Out

At check-out, the applicant completes the process using one of two check-out computers and receives his/her temporary license.

Check-out takes approximately 9 minutes.

3

• Files Menu

• Ribbons

• Project Tabs

• Libraries

• Project

• Current Model

• Properties

• Facility View

Simio User Interface

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 4

Simio Standard Library

Source : Generate entities of a specified type and arrival pattern.

Sink : Destroy entities.

Server : Capacitated process, such as a machine.

Workstation : Capacitated process, includes setup, process, tear-down.

Combiner : Batches entities with a parent entity (e.g., pallet).

Separator : Splits batches or copies entities.

Resource : Seized/Released by objects.

Vehicle : Fixed route or on-demand pickups/drop-offs.

Worker : Moveable resource, for stationary and non-stationary tasks.

BasicNode : Simple intersection, fixed object input.

TransferNode : Change destination/get rides, fixed object output.

Connector : Zero travel time.

Path : Entities independently move at their own speeds.

TimePath : Entities complete travel in a specified time.

Conveyor : Accumulating/non-accumulating conveyor devices.

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 5

Applicants arrive at a rate of approximately

10/hour.

Performance Metrics:

• Server Utilizations

• Time In System

• Number In System

Drivers’ License Office

Check In

Written

Exam

At check-in, a single clerk checks the applicant’s

The written exam is administered by one of two exam clerks.

When an applicant driving history

(if any) and gives the applicant the initial paperwork.

arrives, s/he waits for an available clerk and, once one is available, takes the exam with the clerk.

Check-in takes approximately 5 minutes.

The exam requires approximately 8.8 minutes.

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved

Check Out

At check-out, the applicant completes the process using one of two check-out computers and receives his/her temporary license.

Check-out takes approximately 9 minutes.

6

• So, we need to model:

– Applicant arrival process

Drivers’ License Office

Source

– Check-in process

– Exam process

– Check-out process

– Applicant departure process

– Applicant transfer between processes

Server

Server

Server

Sink

Path

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 7

Build the Initial Model!

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Object Hierarchy - The Family of “Objects”

Object Runspace

( Realization )

Object Instance

Object

Definition

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Initial Object Properties

• Source1 (Source)

– Interarrival Time: Random.Exponential(6) ; units: Minutes

• CheckIn (Server)

– Initial Capacity: 1 (default)

– Processing Time: Random.Exponential(5) ; units: Minutes

• Exam (Server)

– Initial Capacity: 2

– Processing Time: Random.Exponential(8.8) ; units: Minutes

• CheckOut (Server)

– Initial Capacity: 2

– Processing Time: Random.Exponential(9) ; units: Minutes

• Sink1 (Sink)

– All defaults

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 10

Editing Properties

• Displayed in Properties Window

• Defined by object builder

• Integers, Booleans, rules, expressions, …

Expression editor (down arrow at right):

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 11

Applicants arrive at a rate of approximately

10/hour.

Performance Metrics:

• Server Utilizations

• Time In System

• Number In System

Drivers’ License Office

Check In

Written

Exam

At check-in, a single clerk checks the applicant’s

The written exam is administered by one of two exam clerks.

When an applicant driving history

(if any) and gives the applicant the initial paperwork.

arrives, s/he waits for an available clerk and, once one is available, takes the exam with the clerk.

Check-in takes approximately 5 minutes.

The exam requires approximately 8.8 minutes.

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved

Check Out

At check-out, the applicant completes the process using one of two check-out computers and receives his/her temporary license.

Check-out takes approximately 9 minutes.

12

Run Length and Pivot Grid

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 13

Expected “Results” – Static Model

Arrival Rate (per hr)

IAT (mins)

10

6

Split

Capacity

Process Time (mins)

Process Rate (per hr per unit)

Utilization

Num at Station (L)

Time at Station (W - mins)

Check-in Exam Check-out Overall

100.0% 100.0% 100.0%

1 2 2

22.8

5

12.0

83.3%

5

30

8.8

6.8

73.3%

3.2

19.2

9

6.7

75.0%

3.4

20.4

11.6

69.6

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 14

Applicants arrive at a rate of approximately

10/hour.

Performance Metrics:

• Server Utilizations

• Time In System

• Number In System

Drivers’ License Office

Check In

Written

Exam

At check-in, a single clerk checks the applicant’s

The written exam is administered by one of two exam clerks.

When an applicant driving history

(if any) and gives the applicant the initial paperwork.

arrives, s/he waits for an available clerk and, once one is available, takes the exam with the clerk.

Check-in takes approximately 5 minutes.

The exam requires approximately 8.8 minutes.

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved

Check Out

At check-out, the applicant completes the process using one of two check-out computers and receives his/her temporary license.

Check-out takes approximately 9 minutes.

15

Proposed System Modification

Check In

Written

Exam

Add an optional “computerized exam kiosk” to replace one of the two clerks.

Applicants would have a choice between the exam administered by a human clerk and the computerized exam.

The computer kiosk will support two exam-takers at a time.

Initially, assume that ½ of the applicants choose the kiosk and that the exam time is the same as with the human clerk.

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved

Check Out

16

Build the Proposed Configuration Model!

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In-Lab Assignment

Server Utilizations

Ck-In M-Exam C-Exam Ck-Out NIS TIS

Current

Proposed A

Proposed B

Proposed C

• Proposed A - Exponential exam times for both

• Proposed B – Reduced variance on the exam times:

• Human – Random.Triangular(6, 8.8, 11.6)

• Kiosk – Random.Uniform(6, 11.6)

• Proposed C – Same as B, but send 70% to the kiosk (hint: use Selection

Weights on the alternative paths leading from check-in)

• For each metric, report the average and confidence interval half-width (h) based on 25 replications, each of length 1000 hours with a 500 hour warm-up.

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 18

Homework Assignment

• Starting with the “Proposed C” configuration from the in-lab assignment, implement the following exam failure logic:

– When an applicant fails the exam, s/he returns to re-take the exam. The applicant should return to the same exam station (either human or computer)

• Using your modified model, determine the maximum percentage of exam failures that the system can support before becoming unstable

(where the exam servers cannot keep up with the arriving applicants).

• Consider a walk-up bank that that has an ATM, a single teller, and a manager.

• ATM customers visit the ATM and teller customers visit the teller.

• 10% of customers (regardless of original type) visit the manager after visiting the ATM or teller.

• Arrival and service time properties are:

– ATM customers arrive at the rate of 10/hour and spend approximately 4 minutes at the ATM

– Teller customers arrive at the rate of 5/hour and spend approximately 7 minute at the teller

– Customers that visit the manager spend approximately 20 minutes with the manager

• Run 25 replications for 2000 hours each (no warmup) and determine the server utilizations and the times that the customers spend in the system (ATM customers, teller customers, customers that see the manager)

Copyright © 2013 - Jeffrey S. Smith | All Rights Reserved 19