Architecting and designing > Business Process Analysis (BPA) > Simulation of Process Models > Specify how tokens or objects enter a process
  
Specify how tokens or objects enter a process
You must create one or more “tokens” that will pass through a business process flow diagram. A token might represent a reservation request in a reservation system, an unwashed car in a car wash, and so forth.
You can specify more than one token to flow through a process: it is specified in the definition of the Start event on the diagram. You use a UML Object definition as this token. An Object is an instance of a Class. To create an Object, you must also specify the Class that it is instantiating, and the Package that it belongs to.
Create the objects
The object must be created first before you can apply it to a Start Event. You cannot create one in the Start Event definition.
1 Make sure that UML properties are turned on for the encyclopedia (select Tools > Customize Method Support> Encyclopedia Configuration, and then make sure UML is selected. If not, select it, and then reopen the encyclopedia).
2 Create a Class definition for the object, using standard tool techniques to create a new definition of type Class.
3 Create an Object definition, using standard tool techniques to create a new definition of type Object: specify the Object’s package, and the Object's Class (the one you just created).
Assign the objects to the start event
1 Open the definition of the starting event on a business process diagram, go to the Sim Definition tab, and specify that the event is a Start Event in the BPMN Event Type property.
2 Click Apply to save changes to the definition to the repository, register it as a start event, and add new properties and tabs to the dialog for a Start event.
Clicking Apply is the same as closing and reopening the definition.
Arrival profiles
Arrival Profiles represent a constant quantity of objects arriving in a time period. You can specify an Arrival Profile with the definition of BPMN objects to enumerate how often it “arrives” in the business flow.
When defining an Arrival Profile the following Simulation properties apply:
Profile type
You can select Entry or Profile Lists. If you change the given, default choice, you must press the Apply button (or reopen the definition) for the definition dialog to change and present properties relevant to the choice.
Entry, which consists of a single Entry Profile, or
Profile Lists: use this choice if you want to create an Arrival Profile which in itself is made up of a grouping of other Arrival Profiles. For example, you might want to specify a constant rate of arrivals that is made up of individual constant rates for time periods that make up an 8- or 24-hour day (see example below).
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Profile Duration Length/Time Units: Select how long this profile will last.
Inter arrival time
Inter arrivals provide a method of creating object arrivals at regular intervals without the need to specify detailed arrival profiles. Inter arrivals require that the total number of objects (or unlimited) to arrive is specified along with how often one object (or a batch) arrive. Variables can be defined as either constant values, distributions (using the distribution wizard) or predefined variables. The value type list box determines which value is applied to the simulation.
When defining an Inter Arrival Time the following Simulation properties will apply:
Maximum arrivals
Maximum number of objects that can arrive throughout the simulation run.
Maximum Value Type
Specify that the Maximum Value Type is Constant, Distribution, or Variable. If you specify one of these choices, then you only need to fill in the accompanying property from the set below:
Constant: Type in the number of Objects that you want to run the experiment for. For example, when simulating a Car Wash, you might want to look at 500 cars. You would enter the number 500 in this field.
Distribution
Variable
First arrival at
The time of the first object to arrive in the model. You can specify that the First Arrival At property is Constant, Distribution, or Variable. If you specify one of these choices, then you only need to fill in the accompanying property from the set below:
Constant: the Constant Arrival Time by default is set to 0. If you set it to 60 by putting the number 60 in the Constant field of the First Arrival At property, the model will be simulated for 60 time units before the first Object would be brought into the system.
Distribution
Variable
Inter arrival time
Time between the objects arrivals. The time of the first object to arrive in the model. You can specify that the Inter Arrival Time property is Constant, Distribution, or Variable. If you specify one of these choices, then you only need to fill in the accompanying property from the set below:
Constant
Distribution
Variable
Lot size
Number of objects that arrive together. The time of the first object to arrive in the model. You can specify that the Lot Size property is Constant, Distribution, or Variable. If you specify one of these choices, then you only need to fill in the accompanying property from the set below:
Constant
Distribution
Variable
See also
Simulation of Process Models