IE_403_LAB_1

IE 403 SIMULATION

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Atlm University, Department of Industrial Engineering Research Assistant Hale Akkocaolu & Assistant Professor Altan zkil

IE-403 SIMULATION LAAB # 1

Exploring ARENA

Arena is a true Microsoft Windows operating system application, so you can use

shortcut keys such as Ctrl+C for copy. In Arena window, there are nine menus which are

File, Edit, View, Tools, Arrange, Object, Run, Window and Help. The model can be split

into two views: the flowchart view and the spreadsheet view (see Figure 1).

Figure 1. Arena Window

Project Bar hosts panels containing objects with which youll be working, displaying one

panel at a time. In Figure 1, Project Bar is displaying Basic Process Panel which contains

fundamental building blocks, called modules. Reports and Navigate are the other panels

that are currently attach to our Project Bar. For more complex model, other panels will

be needed which are Advanced Process, Advanced Transfer, Elements and Blocks. We

can attach these panels to Project Bar by right-clicking on Project Bar, selecting

Template Panel and attaching required panel from Template file. The steps that are

followed to attaching Advanced Process panel are shown in Figure 2 and Figure 3. Click

on Open button in Attach Template Panel Window, then your Project Bar should look

like Figure 4. You should follow same steps for attaching other required panels.

Project Bar

Status Bar

Model Window

Flowchart View

Model Window

Spreadsheet

View

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Figure 2. Attaching Template Panel 1

Figure 3. Attaching Template Panel 2

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Figure 4. Attached Advanced Process Panel

Modules

The basic building blocks for Arena modules are called modules. These are the

flowchart and data objects that define the process to be simulated and are chosen

from panels in the Project Bar. Modules come in two basic flavors: flowchart and data.

Flowchart modules describe the dynamic process in the model where data modules

define the characteristics of various process elements, like entities, resources and

queues. (see Figure 5.)

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Figure 5. Modules of Basic Process Panel

Model 3-1: Drill Press Example

Well start with a simple case. In this manufacturing system, parts arrive exponentially

with mean 5. If a part arrives and finds the drill press idle, its processing at the drill

press starts right away; otherwise, it waits in First-In First-Out (FIFO) queue.

Processing time for drill press operation is TRIA(1,3,6). After completion of drilling

process, parts leave the system. Run the simulation for 20 minutes.

Building Model

Since youll start to build a model, first you should define your project and running

conditions. In order to do this, first select Run/Setup menu option. Then click on

Project Parameters tab. Enter Project Title, Analyst Name and Project Description.

Select what kind of output performance measures we want to be told about afterwards

from Statistics Collection as shown in Figure 6. For this example, the queue, resource

and entity statistics will be enough.

Flowchart Modules

Data Modules

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Figure 6. Run Setup Option/Project Parameters Tab

Figure 7 shows the Replication Parameters tab of Run/Setup, which controls a number

of aspects about the run. First we need to enter Number of Replication. If we request

multiple replications, we need to tell Arena what to do between replication

(Initialization of System and Statistics). Since we request single replication, we do not

make any changes Initialize Between Replications part. In this case, system has not

warm-up period but in many systems operations cannot start with doors opening. Then

enter replication length and its time unit and if we have any terminating condition, we

should enter this information into Terminating Condition box. The completed tab for

this example is shown in Figure 7.

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Figure 7. Run Setup Option/Replication Parameters Tab

You can also change the animation speed from Run Speed tab of Run/Setup.

After setting the run conditions, we can start construction of our model.

Create Flowchart Module: Click on Create from Basic Process panel and drag and

place it into Flowchart View. Open Create module by double-clicking it to get dialog box

in Figure 8.

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Figure 8. Create Module Dialog Box (By Default)

First change the name of module, Entity Type. In the Time Between Arrivals area of

the dialog box, we accepted the default Random (Expo) for the Type, changed the

default Value of 1 to 5, and selected Minutes as the Units from the drop-down menu.

Finally click OK to save changes and dialog box should look like Figure 9.

Figure 9. Create Module Dialog Box for Model 3-1

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Entity Data Module: Previously, we define Entity Type as Part in Create module. But

you might want to change some things about it. To do this, click the Entity data module

in Basic Process panel. For instance you can change animation picture for Parts as

Figure 10.

Figure 10. Entity Spreadsheet for Model 3-1

Process Flowchart Module: Click on Process module in Basic Process panel and drag it

into flowchart view. Double click on it and edit Process module. After entering name of

the process, you need to select type of action. There are four action options.

Delay: Simply indicates that a process delay will be incurred with no resource

constraint.

Seize Delay: It indicates that a resource(s) will be allocated in this module and a delay

will occur, but that resource release will occur at a later time.

Seize Delay Release: This option indicates that a resource(s) will be allocated followed

by a process delay and then the allocated resource(s) will be released.

Delay Release: This indicates that a resource(s) has previously been allocated and that

the entity will simply delay and release the specified resource(s).

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If you select options except first one you should also add a resource or resources to

seize and/or release.

Then you should define Delay Type, Units and related values. The completed Process

module for this model is shown in Figure 11.

Figure 11. Process Module Dialog Box for Model 3-1

Resource and Queue Data Module: Once youve defined this process module, your

model has both a Resource and a Queue, with names you specified for resource and

default name of ProcessName.Queue for queue. If you want to change default name you

can change it from spreadsheet view of Resource or Queue module.

Dispose Flowchart Module: The final flowchart module is the Dispose; Figure 12

shows how to edit it for this model.

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Figure 12. Dispose Module Dialog Box

Dynamic Plots

To make a plot, press Plot button ( ) on the Animate toolbar to get a blank Plot

dialog box, and then proceed as indicated in Figure 13. You can add expression by

clicking Add button in Plot dialog Box.

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Figure 13. Plot Dialog Box for Model 3-1

While its legal to type in NQ(Drilling Center.Queue) manually for the Expression in the

Plot Expressions secondary dialog box, youd first have to know that this is the right

thing to type in, which you might not know. Arena provides Expression Builder, which you

can access by right-clicking in any box that calls for some kind of Expression, and then

selecting Build Expression. Figure 14 shows the Expression Builder Window after we

expanded the Expression Type tree on the left to get at what we want for the queue-

length plot. The label on the box in the upper right will change depending on what we

select in the Expression Type tree; here it provides a drop-down list where we can

specify the queue for which we want to know the Current Number in Queue. The

current Expression box at the bottom is the Expression Builders answer, and clicking

OK at this point pastes this text back into the Expression box from where we started

with our right-click.

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Figure 14. Expression Builder Dialog Box

The plot for the number busy at the drill press is quite similar, with only two

differences from Figure 13, both of which are in the Plot Expressions secondary dialog

box. First make the Expression NR(Drill Press), an expression you can dscover with

the Expression Builder via the Expression Type path Basic Process Variables >> Resouce

>> Usage >> Current Number Busy, and Select Drill Press under Resource Name. Finally,

make the Maximum 2 since we know this curve will always be at heigth zero or one.

Final view of Model 3-1 is shown in Figure 15.

Figure 15. General View of Model 3-1

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Running It

To Run the model, click the Go button ( ) in the Standard toolbar (or Run >> Go or

pres the F5 key); note that the buttons in this group are similar to those on a video

player. The first time you run a model Arena checks your model for errors (or you can

do this step by itself with the button on the run Interaction toolbar, or Run >>

Check Model or the F4 key); if you have errors, youll gently scolded about them now,

together with receiving some help on finding and correcting them.

The Arena box that appears at the end of the run asks if youd like to see the summary

results. After you look at those reports (or if you choose not to), your model window will

appear to be hung and you cant edit anything. Thats because youre still in run mode for

the model, which gives you a chance to look at the plots and the final status of the

animation. To get out of run mode and back to being able to edit, you have to click End

( ), just like on a video player.

Viewing the Reports

If youd like to see the numerical results now, click Yes in the Arena box that appears

at the end of your simulation. This opens a new reports window in the Arena window.

The Project Bar now displays the Reports panel, which lists several different Reports

you can view, such as Category Overview, Category by Replications, and Resources.

Clicking on each of these reports in the Project Bar opens aa seperate report window in

the Arena window. Dont forget to close these report windows when youre done viewing

them since they dont go away on their own if you simply go back to your model window;

if you change your model then re-run it.

Date post:	17-Oct-2015
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