Basic Simulation

In SAP Signavio Process Manager, the Process Simulation is a dedicated feature that uses typical process metrics to deliver insights on:

• What-if scenarios.
• Process behavior.
• Resource planning and optimization.
• Average costs and times.
• Peaks and bottlenecks.

Why do we apply process simulations?

• To improve existing operations and evaluate new plans and alternatives.
• To avoid time-consuming fine-tuning and expensive testing.
• To reduce cycle times, idle times, and to localize weak points and bottlenecks.
• To evaluate alternative concepts, modified process variants, and capacity expansions.

The BPMN simulation tool allows you to visualize process runs and to analyze processes based on configurable one-case and multiple-case scenarios. You can use it to gain information about cost, cycle times, resources, and bottlenecks. Have a look at the following simulation.

Simulating Business Processes can answer common questions and help to make more well-informed decisions. In this case, we investigate a simple Order-to-Cash process. To ensure that you're making informed decisions, review the following scenarios.

Typical requirement: "How much money does a small decrease in shipment costs save us?"

Activity costs must be provided to calculate the overall process costs. These granular costs can include material, electricity, and other task-specific expenses. Labor costs are set up under Resources. The currency can be configured in the settings.

Typical requirement: "How can a reduced shipment duration influence the total cycle time?"

Execution times for tasks are needed to calculate the (minimum) total cycle time of a process. In practice, the cycle time is more than the sum of time for all task executions. Often, there are awaiting times, idle times, and many more to consider which can have an impact on the process. The simulation focuses mainly on task execution times to calculate the minimum cycle time of a process.

Whenever tasks employees perform, it's natural that the execution time is always different. Therefore, it's helpful to consider deviations for manual tasks. In the Scenarios section, choose Duration > Ellipses icon. Now, you can define your execution time for the task.

Typical requirement: "Can we manage a 40% increase of our order volume?"

To simulate multiple cases, the amount of cases starting during a week must be set up in the Frequency tab. 

The amount of cases can be adjusted to accommodate increases and decreases in the workload, depending on the day of the week and the time of day. In our following example, we have 80 cases per day. This equals 400 cases per week.

Each decision point where the process can take different routes must be configured with an estimation of the respective outcome probabilities. Every time a case reaches these points the given values are used independently of previous cases to route the process.

As you can see in the image above, each decision gateway has a probability field in the Frequency tab.

Typical requirement: "If there are illness-related absences, can we keep up with the order volume?"

The available resources are the most important factor influencing the total cycle time and bottlenecks. 

Resources can be set up with detailed working schedules and hourly wages, which are used to calculate the overall process costs. You can edit working schedules for each lane in the Resource tab.

The metrics of the results of a multiple-case simulation.

The overall process costs are the sum of fixed activity costs and resource costs. If deviations for an activity time are used, they can vary based on execution time.

The total cycle time is the sum of all execution and waiting times. Long maximum times usually indicate a bottleneck in the respective lane causing long waiting times due to a lack of resources.

The total cycle time can exceed the simulation time span for two reasons:

• Your resources can't handle cases fast enough and process instances accumulate.
• The cases that occur in the last hours/minutes of your simulation time frame exceed the frame before they’re completed.

The resource consumption table shows how much of their work time that the process participants must spend on the simulated process.

In the bottleneck tab, the pure waiting times are listed on an activity level. This list indicates where the process must be adjusted, or if more employees are required.

A simulation run has discovered two bottlenecks in the Finance and Order Fulfillment Department.

A bottleneck occurs when a resource's limited availability increases the waiting times of cases. When a new case started, the resource was still handling a previously started instance. Adding extra resources for both resources can reduce waiting times and cycle times.