Preface

Welcome to the Agile Model-Based Systems Engineering Cookbook! There is a plethora of published material for agile methods, provided that you want to create software. And the system is small. And the team is co-located. And it needn’t be certified. Or safety-critical or high-reliability.

MBSE is none of these things. The output of MBSE isn’t software implementation but system specification. It is usually applied to more complex and larger-scale systems. The teams are diverse and often spread out across departments and companies. Much of the time, the systems produced must be certified under various standards, including safety standards. So how do you apply agile methods to such an endeavor?

Most of the work in MBSE can be thought of as a set of workflows that produce a set of interrelated work products. Each of these workflows can be described with relatively simple recipes for creating the work products for MBSE including system requirements, systems architecture, system interfaces, and deployment architectures. That’s what this book brings to the table and what sets it apart.

In this second edition, some new recipes have been added and all the examples and figures have been done using the Cameo Systems Modeler SysML tool.

Who this book is for

The book is, first and foremost, for systems engineers who need to produce work products for the specification of systems that include combinations of engineering disciplines, such as software, electronics, and mechanical engineering. More specifically, this book is about model-based systems engineering using the SysML language to capture, render, and organize the engineering data. Further, the book is especially about how to do all that in a way that achieves the benefits of agile methods – verifiably correct, adaptable, and maintainable systems. We assume basic understanding of the Systems Modeling Language (SysML) and at least some experience as a systems engineer.

What this book covers

Chapter 1, Basics of Agile Systems Modeling, discusses some fundamental agile concepts, expressed as recipes, such as managing your backlog, using metrics effectively, managing project risk, agile planning, work effort estimation and prioritization, starting up projects, creating an initial systems architecture, and organizing your systems engineering models. The recipes all take a systems engineering slant and focus on the work products commonly developed in a systems engineering effort.

Chapter 2, System Specification, is about agile model-based systems requirements – capturing, managing, and analyzing the system specification. One of the powerful tools that MBSE brings to the table is the ability to analyze requirements by developing computable and executable models. This chapter provides recipes for several different ways of doing that, as well as recipes for model-based safety and cyber-physical security analysis, and specifying details of information held within the system.

Chapter 3, Developing Systems Architecture, has recipes focused on the development of systems architectures. It begins with a way of doing model-based trade-studies (sometimes known as “analysis of alternatives”). The chapter goes on to provide recipes for integrating use case analyses into a systems architecture, applying architectural patterns, allocation of requirements into a systems architecture, and creating subsystem-level interfaces.

Chapter 4, Handoff to Downstream Engineering, examines one of the most commonly asked questions about MBSE: how to hand the information developed in the models off to implementation engineers specializing in software, electronics, or mechanical engineering. This chapter provides detailed recipes for getting ready to do the hand off, creating a federation of models to support the collaborative engineering effort to follow, converting the logical systems engineering interfaces to physical interface schemas, and actually doing the allocation to the engineering disciplines involved.

Chapter 5, Demonstration of Meeting Needs Verification and Validation, considers a key concept in agile methods: that one should never be more than minutes away from being able to demonstrate that, while the system may be incomplete, what’s there is correct. This chapter has recipes for model simulation, model-based testing, computable constraint modeling, adding traceability, how to run effective walkthroughs and reviews, and – my favorite – Test-driven modeling.

Appendix, The Pegasus Bike Trainer, details a case study that will serve as the basis for most of the examples in the book. This is a “smart” stationary bike trainer that interacts with net-based athletic training systems to allow athletes to train in a variety of flexible ways.

It contains aspects that will be implemented in mechanical, electronic, and software disciplines in an ideal exemplar for the recipes in the book.

To get the most out of this book

To get the most out of this book, you will need a solid, but basic, understanding of the Systems Modeling Language (SysML). In addition, to create the models, you will need a modeling tool. The concepts here are expressed in SysML so any standards-compliant SysML modeling tool can be used.

All the example models in this book are developed using the Cameo Systems Modeler tool. To execute models and run simulations, you will need the Simulation Toolkit, included with the tool:

Software/hardware covered in the book	OS requirements
Cameo Systems Modeler	Windows, macOS, or Linux

Download the example models

You can download the example models for this book from the author’s website at www.bruce-douglass.com. Note that these models are all in Cameo-specific format and won’t generally be readable by other modeling tools.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

Where to go from here

Visit the authors, website at www.bruce-douglass.com for papers, presentations, models, engineering forums, to download the models from this book, and more.

Download the color images

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: https://packt.link/av1n2.

Conventions used

There are a number of text conventions used throughout this book.

Bold: Indicates a new term, an important word, or words that you see on the screen. For instance, words in menus or dialog boxes appear in the text like this. For example: “Select System info from the Administration panel.

Get in touch

Feedback from our readers is always welcome.

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