Event Process Chain

April 19, 2012

An Event Process Chain is a type of flowchart used for business process modeling. Event Driven Process Chain can also be used for configuring an enterprise resource planning and business process improvement. Businesses are using EPC diagrams to lay out business process work flows. EPC diagrams use symbols of several kinds to show the control flow structure of a business structure.
The EPC method was developed within the framework of ARIS, constructed by Professor Wilhelm-August Scheer. (Architecture of Integrated Information Systems), is an approach to enterprise modeling. ARIS offers methods for analyzing processes and taking a holistic view of process design, management, work flow, and application processing. As such it forms the core technique for modeling in ARIS, which serves to link to different views in the so-called control view.
The EPC publication quotes “An EPC is an ordered graph of events and functions. It provides various connectors that allow alternative and parallel execution of processes. In addition to it is specified by the usages of logical operators. A major strength of EPC is said to be its simplicity and easy to understand the process. This makes EPC a widely acceptable technique to denote business processes.” Events are passive elements in EPC. They describe under what circumstances a function or process works. Examples of events are “requirement captured” and “material on stock.”On the EPC graph an event is represented as a hexagon. The diagram must start with an event and end with a event.
Functions are active elements in EPC. They model the task s or activities within the company. Functions describe transformations from an initial state to a resulting state. Examples of functions are “capture requirement” and “check material on stock.” On the EPC diagram a function is represented by a rounded rectangle.
Organization units determine which person or organization within the structure of an enterprise is responsible for a specific function. Examples are “sales manager and sales department.” Organization is represented by an ellipse with a vertical line.
In the EPC, the information, material, or resource object portray objects in the real world. Examples are “material” and “order.” The object is represented as a rectangle.
In the EPC the logical relationships between elements in the control flow is events and functions are described by logical connectors. There are three kinds of logical relationships defined in EPC: 1.) Branch and merge correspond to making decision of which path to choose among several control flows. The branch activates exactly only one of the outgoing control flows and deactivates the others. A branch in the EPC is represented by an opening XOR, whereas a merge is represented as a closing XOR connectors.
2.) Fork and join correspond to activating all paths in the control flow concurrently. A fork has one incoming control flow and two or more outgoing control flows. When the condition is completed, a fork activates all of the outgoing control flows in parallel. A join may have two or more incoming control flows and one outgoing control flow. A join locks into all activated incoming control flows. A fork in the EPC is represented by an opening “AND”, and join is represented as a closing “AND” connectors.
3.) An ‘OR’ relationship corresponds to activating one or more paths among control flows. When at least one of the incoming control flows is activated, the closing ‘OR’ connector will pass the control to the next element after it.
A control flow connects events with functions, process paths, or logical connectors creating a sequence and logical between them. A control flow is represented as a dashed arrow.
Information flows show the connection between functions and input or output data, upon which the function reads changes or writes. Organization unit assignments show the connection between an organization unit and the function it is responsible for. Process paths serve as navigation aid in the EPC.
Event-driven Process Chains are best used in place of any other process diagram if the process begins with a specific event. This event sets the situation for the rest of the process. It is not just a process, but a process completed under very specific circumstances. • Start the diagram. An Event-driven Process Chain begins with an event, symbolized by a hexagon. Add an event to the top of the page. • Add a function. Functions are represented by rounded rectangles and represent an action or process taken that leads from one state to the next.
• Input and output. Input and output from outside or inside sources can also trigger certain functions or processes and are symbolized by rounded rectangles with a vertical line through it.
• Add information. Information or materials are represented by rectangles. • Make connections. Use arrows to connect between two different nodes. You may also branch off if one node may lead to one of two others. You may also use a fork or join two different process flows together, in other words, two nodes lead to the same conclusion.
• Finish. In an Event-driven Process Chain must finish with an event. To best sum up event driven process given by Dr. Mani Chandy, is one is you need to continuously acquire data and there are various ways in which this is done. Some of it is done through sensors. Companies and enterprises all over are finding that they have a lot more sensors in their manufacturing and logistics and they’re generating a lot more statistics than they’re actually using. So number one is the acquisition of data, and two is the fusion of data – correlating data from multiple sources of information. Once you fuse the data you have an idea of what the world is like outside and how it’s changed. And so the third part is to plan. You want to plan a response to this change. And the fourth part is to execute the response. The combination of all four parts is what makes event processing very useful to the business.

Work Cited: Wikipedia, Visipedia, and Dr. Mani Chandy author of Event Processing: Designing IT Systems for Agile Companies
Event driven process.docx


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