Thorsten Cziharz Peter Hruschka Stefan Queins Thorsten Weyer Handbook of Requirements Modeling According to the IREB Standard Education and Training for IREB Certified Professional for Requirements Engineering Advanced Level "Requirements Modeling" Version 1.3 August 2016 Translated from German by: Ed van Akkeren, Lars Baumann, Jan Jaap Cannegieter, Colin Hood, Peter Hruschka, Matthias Lampe, Ellen Leutbecher, Hans van Loenhoud, Piet de Roo, Stefan Staal, and Johan Zandhuis The compilation of this handbook was supported by Terms of Use 1. Any individual or training provider may use this handbook as a basis for seminars provid- ed that the copyright holders are acknowledged and the source and owner of the copyright is named. In addition, this handbook may be used for advertising purposes with the consent of the IREB. 2. Any individual or group of individuals may use this handbook as a basis for articles, books, or other derived publications provided that the authors and the IREB are credited as the source and owners of the copyright. This work, including all its parts, is protected by copyright. Use of the document is permit- ted—where this is not permitted explicitly—by copyright law only with the consent of the copyright owners. This applies in particular to reproductions, adaptations, translations, mi- crofilming, storage and processing in electronic systems, and public disclosure. Thanks Our thanks to Torsten Bandyszak, Sibylle Becker, Nelufar Ulfat-Bunyadi, Ruth Rossi, Tracy Duffy, and Stefan Sturm for their support in the preparation of the manuscript. This handbook was produced by (in alphabetical order): Thorsten Cziharz, Dr. Peter Hruschka, Dr. Stefan Queins, and Dr. Thorsten Weyer Copyright © 2016 "Handbook of Requirements Modeling According to the IREB Standard" is with the authors listed. Rights are transferred to the IREB International Requirements Engi- neering Board e.V. Table of Contents 1 Basic Principles ................................................................................................................................................. 1 1.1 The Benefits of Modeling Requirements .................................................................................... 1 1.2 Applications of Requirements Modeling .................................................................................... 2 1.3 Terms and Concepts in Requirements Modeling .................................................................... 2 1.4 Requirements Models ........................................................................................................................ 3 1.5 Views in Requirements Modeling ................................................................................................. 6 1.6 Views of the Dynamic View in Requirements Modeling ....................................................... 8 1.7 Adapting Modeling Languages for Requirements Modeling............................................... 9 1.8 Integrating Textual Requirements in the Requirements Model ...................................... 10 1.9 Documenting Dependencies between Model Elements ..................................................... 10 1.10 The Benefits of Requirements Modeling .................................................................................. 11 1.11 The Quality of Requirements Models ........................................................................................ 12 1.12 Further Reading ................................................................................................................................. 14 2 Context Modeling .......................................................................................................................................... 15 2.1 Purpose .................................................................................................................................................. 15 2.2 Context Diagrams .............................................................................................................................. 15 2.3 Other Types of Context Modeling ................................................................................................ 18 2.4 Further Reading ................................................................................................................................. 18 3 Information Structure Modeling ............................................................................................................. 19 3.1 Purpose .................................................................................................................................................. 19 3.2 Modeling Information Structures ................................................................................................ 19 3.3 Simple Example .................................................................................................................................. 20 3.4 Modeling Classes, Attributes, and Data Types ........................................................................ 20 3.5 Modeling Relationships ................................................................................................................... 29 3.6 Modeling Generalizations and Specializations ....................................................................... 36 3.7 Other Modeling Concepts ............................................................................................................... 38 3.8 Further Reading ................................................................................................................................. 39 4 Dynamic Views ............................................................................................................................................... 41 4.1 Dynamic Views of Requirements Modeling ............................................................................ 41 4.2 Use Case Modeling ............................................................................................................................. 41 4.3 Data Flow-Oriented and Control Flow-Oriented Modeling of Requirements ............ 48 4.4 State-Oriented Modeling of Requirements .............................................................................. 61 4.5 Further Reading ................................................................................................................................. 78 5 Scenario Modeling ........................................................................................................................................ 79 5.1 Purpose .................................................................................................................................................. 79 5.2 Relationship between Scenarios and Use Cases .................................................................... 80 5.3 Approaches to Scenario Modeling............................................................................................... 80 5.4 Simple Examples of a Modeled Scenario .................................................................................. 81 5.5 Scenario Modeling using Sequence Diagrams ........................................................................ 83 5.6 Scenario Modeling with Communication Diagrams ............................................................. 91 5.7 Examples of Typical Diagrams in the Scenario View ........................................................... 91 5.8 Further Reading ................................................................................................................................. 95 Glossary ..................................................................................................................................................................... 97 List of Abbreviations ......................................................................................................................................... 103 References ............................................................................................................................................................. 105 IREB CPRE Advanced Level Module "Requirements Modeling" In recent years, the scope and complexity of typical software-based systems have increased significantly. This is reflected directly in the number of requirements arising and the com- plexity in terms of the mutual dependencies between requirements. All forecasts about the expected future increase in the size and complexity of software-based systems predict that the number of requirements and the complexity of interdependencies will continue to in- crease dramatically in the future. This becomes clear, for example, if we consider the devel- opment trends in the field of business information systems in terms of the Internet of Ser- vices (IoS) and Internet of Things (IoT) or the development in the field of intelligent embed- ded systems. Both trends are paving the way for a somewhat revolutionary penetration of the physical world by dynamic networked software-based systems, referred to as "cyber- physical systems". The first thing to note is that requirements are taking a central role in the development pro- cess of software-based systems. What is more, the extent and complexity of the require- ments of a system are becoming more difficult to handle. Accordingly, the specification of requirements has already reached its limits in many areas if this is done only in natural lan- guage (i.e., in text form). In many cases, this has