1.1 Preliminary Remarks

The topic of process design and process optimization is of central importance for all companies and other organizations. It is a continuous task. However, process optimization requires that processes first be identified and described by means of process models. Only after this documentation has been carried out can weaknesses be identified and eliminated, and new approaches to process design - within the context of digitalization and automation - be incorporated.

Significant changes have also occurred in the methods used over the past ten years. New methods have emerged, such as BPMN, while others that never truly gained acceptance in process modeling - such as UML activity diagrams - have largely disappeared. Event-driven Process Chains (EPCs), however, remain the ideal instrument for modeling processes in the context of an as-is analysis: they are simple, quick to learn, and nevertheless provide expressive process models, as will hopefully become clear in this text. One cannot reasonably expect more from a method. If, within the scope of requirements engineering, a more implementation-oriented modeling of processes is desired, other instruments should be chosen - for example, BPMN.

Methods

For presenting process examples, I use the terms concrete example and abstract example. Concrete examples illustrate a process (or a process segment) using specific, domain-related situations. They show how a process works in practice by referring to realistic tasks, documents, and decisions. Abstract examples, by contrast, use simplified and generic constructs that are independent of any specific application domain. Their purpose is to highlight the underlying syntactic modeling principles without being distracted by domain-specific details.

Process Examples

1.2 List of Abbreviations

The following abbreviations are used throughout this text. They correspond to standard terminology in process modeling and related disciplines. Abbreviations that appear in Event-Driven Process Chains (EPCs) and Business Process Diagrams (BPDs) are explained within the respective process models.

1.3 Structure of This Work

This text is designed to introduce readers step by step to the modeling of business processes using Event-Driven Process Chains (EPCs) and Business Process Diagrams (BPDs) of BPMN. The structure follows this intent.

• Chapter 2 presents, in general terms, how the literature defines business processes and process modeling.

Beginning with Chapter 3, the focus shifts to EPCs.

• Chapter 3 introduces the foundational concepts as defined by the originators of the method (Scheer and his team).
• Chapter 4 deepens this understanding by presenting the basic patterns that can occur in EPCs.
• Chapter 5 provides an introduction to process modeling with EPCs through a commented example.
• Chapter 6 summarizes the syntactic rules, offers recommendations for the pragmatics of process modeling, and outlines several design guidelines.

Further discussions of EPCs and their modeling can be found in [Staud 2025]. This includes, in Chapter 8, numerous examples of EPCs with different modeling emphases.

Beginning with Chapter 7, this text turns to BPMN.

• Chapter 7 describes how the authors of BPMN conceptualize business processes.
• Chapter 8 presents introductory examples that illustrate the most important components and structural characteristics.
• Chapter 9 addresses the documentation of individual process steps.
• Chapter 10 explains how information and its processing are represented in BPDs.
• Chapter 11 describes how events are viewed and captured in BPMN.
• Chapter 12 is dedicated to the representation of sequence flows.
• Chapter 13 elaborates on gateways, the operators of BPMN, building on the discussions introduced earlier.