Learning Simio Lab Series 1 Lab Module 01 Evaluating Potential Modifications to a Driver’s License...

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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

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

Objectives and Outline

• Objectives– Learn the basics of:

• The Simio user-interface• Modeling in Simio• Using the Simio Pivot Grid

• Outline1. Description of the system to be modeled2. Introduction to the Simio user interface3. Model the “current” configuration4. Experiment and verify the current model5. Model the “proposed” configuration6. In-lab and take-home assignments

Video 1

Video 2

Video 4

Video 5

Video 3


Drivers’ License Office

Written Exam

The written exam is administered by one of two exam clerks. When an applicant arrives, s/he waits for an available clerk and, once one is available, takes the exam with the clerk.

The exam requires approximately 8.8 minutes.

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.

Check In

At check-in, a single clerk checksthe applicant’s driving history(if any) and gives the applicant the initial paperwork.

Check-in takes approximately 5 minutes.

Applicants arrive at a rate of approximately 10/hour.

Performance Metrics:• Server Utilizations• Time In System• Number In System


Simio User Interface

• Files Menu• Ribbons• Project Tabs• Libraries• Project• Current Model• Properties• Facility View


Simio Standard LibrarySource: 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.



Written Exam



Check Out



Check In







• So, we need to model:– Applicant arrival process

– Check-in process

– Exam process

– Check-out process

– Applicant departure process

– Applicant transfer between processes

Source

Sink

Server

Server

Server

Path


Build the Initial Model!


Object Hierarchy - The Family of “Objects”

Object Definition

Object Instance

Object Runspace(Realization)


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


Editing Properties

• Displayed in Properties Window• Defined by object builder• Integers, Booleans, rules, expressions, …• Expression editor (down arrow at right):



Written Exam



Check Out



Check In






Run Length and Pivot Grid


Expected “Results” – Static Model

Arrival Rate (per hr) 10

IAT (mins) 6

Check-in Exam Check-out Overall

Split 100.0% 100.0% 100.0%

Capacity 1 2 2

Process Time (mins) 5 8.8 9 22.8

Process Rate (per hr per unit) 12.0 6.8 6.7

Utilization 83.3% 73.3% 75.0%

Num at Station (L) 5 3.2 3.4 11.6

Time at Station (W - mins) 30 19.2 20.4 69.6



Written Exam



Check Out



Check In






Proposed System Modification

Check InWritten Exam

Check Out

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.


Build the Proposed Configuration Model!


In-Lab Assignment

• 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.

Server Utilizations

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

Current

Proposed A

Proposed B

Proposed C


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)

Date post:	01-Apr-2015
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Learning Simio Lab Series 1 Lab Module 01 Evaluating Potential Modifications to a Driver’s License...

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