Systems Engineering Demystified

A practitioner's handbook for developing complex systems using a model-based approach

Jon Holt

• Publisher: Packt Publishing
• Year: 2021
• ISBN:
  9781838985448
• Topic: Computer Science
• Subtopic: Systems Architecture
• Index: Computer Science

Get to grips with systems engineering life cycles, processes, and best practices and discover techniques to successfully develop complex systems

Key Features

• Discover how to manage increased complexity and understand systems better via effective communication
• Adopt a proven model-based approach for systems engineering in your organization
• Apply proven techniques for requirements, design, validation and verification, and systems engineering management

Book Description

Systems engineering helps us to understand, specify, and develop complex systems, and is applied across a wide set of disciplines. As systems and their associated problems become increasingly complex in this evermore connected world, the need for more rigorous, demonstrable, and repeatable techniques also increases.Written by Professor Jon Holt – an internationally recognized systems engineering expert – this book provides a blend of technical and business aspects you need to understand in order to develop successful systems. You'll start with systems engineering basics and understand the complexity, communication, and different stakeholders' views of the system. The book then covers essential aspects of model-based systems engineering, systems, life cycles, and processes, along with techniques to develop systems. Moving on, you'll explore system models and visualization techniques, focusing on the SysML, and discover how solutions can be defined by developing effective system design, verification, and validation techniques. The book concludes by taking you through key management processes and systems engineering best practices and guidelines.By the end of this systems engineering book, you'll be able to confidently apply modern model-based systems engineering techniques to your own systems and projects.

What you will learn

• Understand the three evils of systems engineering - complexity, ambiguous communication, and lack of understanding
• Realize successful systems using model-based systems engineering
• Understand the concept of life cycles and how they control the evolution of a system
• Explore processes and related concepts such as activities, stakeholders, and resources
• Discover how needs fit into the systems life cycle and which processes are relevant and how to comply with them
• Find out how design, verification, and validation fit into the life cycle and processes

Who this book is for

This book is for aspiring systems engineers, engineering managers, or anyone looking to apply systems engineering practices to their systems and projects. While a well-structured, model-based approach to systems engineering is an essential skill for engineers of all disciplines, many companies are finding that new graduates have little understanding of systems engineering. This book helps you acquire this skill with the help of a simple and practical approach to developing successful systems. No prior knowledge of systems engineering or modeling is required to get started with this book.

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Section 1: Introduction to Systems Engineering

In this section, we will understand what Systems Engineering is and why there is a growing need for such an approach with today's increasingly complex systems.

This section has the following chapters:

• Chapter 1, Introduction to Systems Engineering
• Chapter 2, Model-Based Systems Engineering

Chapter 1: Introduction to Systems Engineering

This chapter focuses on the background of systems engineering, considering the history of the subject and why it is needed. This chapter will also provide an understanding of the main concepts associated with systems engineering and the terminology that will be adopted throughout this book, thus aiding our understanding of the topic as we progress. To do this, we will look at the following topics:

• A brief history of systems engineering
• Defining systems engineering
• The need for systems engineering

A brief history of systems engineering

It may be argued that systems engineering has been being employed ever since mankind started building and developing complex systems. It could also be said that the pyramids in ancient Egypt are examples of complex systems, along with simple stone structures, such as henges, which may actually form part of a larger astrological system. Furthermore, mankind has been observing complex systems such as the solar system since the ancient Greeks first observed the motion of the planets and created the model of the geocentric universe.

In more recent times, the term systems engineering may be traced back to the early part of the 20th century in Bell Laboratories in the USA (Fagen 1978). Examples of systems engineering may be observed in the Second World War and the first attempt to teach systems engineering is claimed to have been in 1950 at MIT (Hall 1962).

The 1960s saw the formulation of the field of study known as systems theory, which was first postulated by Ludwig von Bertalanffy (Bertalanffy 1968) as "general systems theory."

The main tenet of systems theory is that it is a conceptual framework based on the principle that the component parts of a system can best be understood in the context of the relationships with each other and with other systems, rather than in isolation (Wilkinson 2011). This is essential for all systems engineering as it means that elements in a system, or the systems themselves, are never considered by themselves but in relation to other elements or systems.

As systems became more complex, the need for a new approach to developing systems became more prevalent. Throughout the latter part of the 20th century, this need grew until it reached the point, in 1990, that the National Council on Systems Engineering (NCOSE) was founded in the USA. Since then, this organization has evolved into the International Council on Systems Engineering (INCOSE), in 1995, which is the world's foremost authority on systems engineering and has over 70 chapters throughout the world.

Today, as the complexity of the world that we live in and the systems that are being developed are increasing at an ever-expanding rate, there is an increased need for approaches that are rigorous and robust and can cope with these high levels of complexity. Systems engineering is such an approach.

Defining systems engineering

When considering systems engineering as a topic, it is important to understand exactly what is meant by the key terms that are being used. One aspect of all engineering (and all other professions for that matter) that will emerge from this book very quickly is that there is seldom a single, definitive definition for any term. This creates a potential problem as communication, as will be discussed later in this chapter, is key to successful systems engineering.

In order to address this potential problem, this chapter will introduce, discuss, and define specific concepts and their associated terminology that will be used throughout the book. This will enable a domain-specific language to be built up that will then be used consistently throughout this book. Wherever possible and appropriate, the terminology adopted will be based on international best practices, such as standards such as ISO 15288 (ISO 2015), to ensure the provenance of the information presented here.

Defining a system

The first concept that will be discussed is that of a system. A system will be defined in different ways by different people, depending on the nature of the system. So, first of all, some types of systems will be identified to illustrate some of the typical types of systems that may be encountered in systems engineering.

There are many different classifications, or taxonomies, of systems and one of the more widely accepted classifications is the one defined by Peter Checkland (Checkland, 1999), which is illustrated in the following diagram:

Figure 1.1 – Checkland's five types of system

The diagram in Figure 1.1 shows Checkland's five types of generic systems, which are as follows:

• Natural systems, which represent open systems whose characteristics are beyond the control of humans. Such systems include weather systems, nature, the environment, time, and so on.
• Designed physical systems, which represent what most people would immediately think of when considering a system, such as smartphones, tablets, helicopters, cars, trains, planes, spaceships, boats, TVs, cameras, bridges, computer games, satellites, and even domestic appliances. The list is almost endless. The systems will typically consist of physical artifacts that represent the real-world manifestation of the system.
• Designed abstract systems, which represent systems that have no physical artifacts but that are used by people to understand or explain an idea or concept. Examples of such systems include models, equations, thought experiments, and so on.
• Human activity systems, which are people-based systems that can be seen or observed in the real world. These systems will typically consist of different sets of people interacting to achieve a common goal or purpose. Examples of such systems include a political system, social groups, people-based services, and so on.
• Transcendental systems, which are systems that go beyond our current understanding. Examples of such systems include deities, unknown problems, and Numberwang.

This is a good set of classifications that will be the one that is used as a reference in this book. These classifications are a good way to think about different types of systems, but the important point to understand here is that we can apply systems engineering to all five of these different categories of systems.

Also, it should be kept in mind that it is possible to have systems that actually fit into more than one of these categories. Imagine, for example, a transport system that would have to take into account: vehicles (designed physical systems), operating models (designed abstract systems), the environment (a natural system), and the governing political system (a human activity system). In real life, the complexity of systems is such that it is typical, rather than unusual, to encounter examples of these systems that can fit into multiple categories.

Characteristics of a system

The five different broad types of systems have been introduced, but there is also a common set of characteristics that may be associated with all of these types of systems. These characteristics allow the systems to be understood and developed. Let's explore these in the following sections.

System elements – characterizing system structure

Any system will have its own natural structure and may be thought of as a set of interacting system elements, as shown in the following diagram:

Figure 1.2 – Basic structure of a system – system elements

The diagram in Figure 1.2 shows that a system is made up of a set of system elements and that there are two types of systems: a system of interest and an enabling system. System of interest refers to a system...