Websphere Business Modeler 6.1 Tutorials: How to set simulation preferences

Quickstart tutorial 4-How to set simulation preferences

How to set simulation preferences

How to set simulation preferences

Introduction

Simulation settings/attributes control the behavior of your simulation runs so that your simulation snapshots and results can be useful reflections of real-world behavior.

When you run a simulation, you can define the variables that you want to measure and analyze. For example, you can specify what each task will cost, how much revenue those same tasks will generate, and how long (in virtual time) a particular process will run.

Simulation attributes can be set at multiple levels.

Simulation preferences
At the highest level of application are the simulation preferences. Values for these attributes are set through the preferences window, and are used as default values for new simulation snapshots and profiles.

Simulation preferences can be set at any time, and all simulation snapshots that you create after you update the preferences will inherit those preferences.
Simulation snapshot
At the next level of specificity are the simulation snapshot settings. The simulation snapshot settings present a subset of the attributes available in the preferences. The initial values for these attributes are taken from the preferences. However, you can override these values by editing the "snapshot defaults".

Simulation snapshot settings will override preferences. A simulation snapshot is a record of a modeling project at the single moment when the snapshot is created. When you create a simulation snapshot, simulation default values are created as part of the snapshot. When you update the default settings (located in the Defaults folder of the snapshot), all simulation profiles that you subsequently create will inherit those new attributes.
Simulation profile
More specific than the simulation snapshot settings are values inside a particular simulation profile. These settings, take their initial values from a combination of the simulation preferences and simulation snapshot settings. When you run a simulation or carry out an analysis on a simulation profile, it is the simulation profile settings that are used. Overriding the values of a specific profile affect the details of simulations you run against the profile, which will be reflected in any dynamic analyses you run against those results.

Process and task settings are specific to a single simulation profile, and will override both preferences and snapshot settings. You can update process and task settings of an individual simulation profile using the Attributes View.

How to set simulation preferences

For the Quickstart Finance Loan Application process, the default cost for each of the tasks is currently zero. You are going to update the simulation preferences to indicate that each task in the process costs US$1.50 to perform.

To view and set simulation preferences, complete the following steps:

On the menu bar, click Window > Preferences. The Preferences window opens.
In the navigation tree, expand Business Modeling and then expand the Simulation folder to view the various simulation preferences. You can set preferences for the following categories: Database Connection, General, Labels, Tasks, Token Creation, and Visual Attributes. For the purposes of this tutorial, you will only update the Task preferences, but you can open and examine each category to become familiar with the different preferences that you can set at this level.
In the navigation tree, click Tasks. The Task pane opens.
Click the Cost and revenue tab. The Cost and revenue fields are displayed, as in the following image:
Update the cost of performing each task in your simulations:
1. In the Cost incurred every time a task runs field, click Edit. A window opens.
2. Click the Specific value radio button, then type the following value: 1.50
3. Click OK. The window closes.
4. Leave the currency as the default USD. You have now specified that every task completed in your simulation will cost U.S. $1.50. (Note that you can also restore the default attribute values by clicking Restore Defaults in the Preferences window.)
Click OK. The Preferences window closes.

You have now set the simulation preferences that each new simulation snapshot will inherit. Later in this module, you will see how the change that you have made in this exercise, increasing the cost of each task to U.S. $1.50 from zero, will affect the outcome of your simulations. Remember, you can update these preferences at any time, and any simulation snapshots or profiles that you subsequently create will inherit those updated preferences.

Now you can prepare to run a simulation by creating a simulation snapshot.

Simulation preferences settings

You can update the following simulation preferences settings:

Setting the database connection preferences
Derby is provided as the default database to store simulation results, but you can also set the preferences to use a locally installed copy of IBM® DB2 Universal Database™ Express Edition if you require higher performance during simulation and analysis.
Specifying general simulation preferences
General simulation preferences define conditions and behaviors for a process as a whole during a simulation. Attributes that you set in the simulation preferences provide default values for simulation snapshots, and their initial profiles.
Setting the simulation profile label preferences
Set the simulation labelling preferences to create a set of default display behaviors for new simulation profiles. These preferences dictate whether labels are initially displayed in simulation profiles, and specify the content that is displayed in each label. For example, you can choose to display the associated data for repositories, and the organizations and locations for tasks.
Choosing the label display behavior for new simulation profiles
You can choose one of two sets of label preferences to use when you create new simulation profiles. You can either choose to reuse the labelling preferences that you defined for display of the process models as you edit them, or you can use your own specific simulation diagram label preferences. You can change the preferences that you are using as your default in the Simulation preferences window.
Setting diagram display preferences
WebSphere Business Modeler allows you to display your simulation profile diagrams using enhanced graphics, or basic graphics.
Setting task simulation preferences (General tasks , Cost and Revenue task )
Task simulation attributes define conditions and behaviors for individual activities within a process during a simulation. Use the task simulation preferences to define default values for these attributes so that they are applied to all new simulation snapshots that you create.
Specifying token creation preferences
You can specify preferences for token creation settings to apply to the inputs of all new simulation snapshots you create.
Setting layout preferences
You can specify the amount of space that the Auto-Layout option will leave between nodes in the process diagram and the simulation diagram.