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Where we are Heading

The discipline of Systems Engineering dates back to the early 1900's; the term is thought to have been first coined by Bell Laboratories in the early 1940's. Sixty-odd years would pass before the need for a dedicated language for modeling systems was perceived in 2001, but it wasn't until 2006 that the Systems Modeling Language (SysML) was adopted by the Object Management Group and became the language of choice for describing systems.

In the field of Systems Engineering, Enterprise Architect has become the tool of choice for many leaders in the industry, because of its flexible, extensible and pragmatic approach to modeling complex systems and its strong compliance with the Systems Modeling Language specification.

An example of a SysML conceptual diagram in Enterprise Architect.

As a platform, Enterprise Architect offers a unique capability in supporting the integration of strategic, business, engineering and technology models, from motivation models through to the implementation of systems and continuing on to support. The tool helps the System Engineer to create Strategic models - including diagrams such as the Balanced Scorecard - Capability models, Tactical models - such as Gap Analysis and Roadmaps - and Operational models, appealing to stakeholders including the senior executives, engineering managers, solution and implementation teams, and engineers.

How it will help you

Readers will typically come to the topic of Model Based Systems Engineering with some existing knowledge or experience even if it is something that has been learnt in lectures or by on the job training, or perhaps by using a different tool. Readers will benefit by understanding Enterprise Architect's features and the tools that are available to develop and manage Model Based Systems Engineering models in Enterprise Architect. This knowledge will enable them to be more productive as an individual and also as a member of a team. The reader will also learn about the syntax and semantics of the Systems Modeling Language popularly know as SysML and how it can be used to model and even to simulate complex engineering systems.

Who will benefit

Anyone involved in the development, management or support of Model Based Systems Engineering initiatives whether at a:

  • Strategic level,
  • Business Value level,
  • Management Level or
  • Engineering level

will benefit from reading this information. This covers a wide range of roles including:

  • Customers,
  • Strategic Thinkers,
  • Senior Management,
  • Engineering Management,
  • System Designers and Architects,
  • Software Designer and Architects,
  • Systems Engineers,
  • Software Engineers,
  • Fabrication Teams,
  • Implementation Teams,
  • Support Staff.

The real power of this way of working and using Enterprise Architect as a tool is in the unification of the interdisciplinary teams. Thus allowing people from a wide range of disciplines, potentially geographically dispersed and working at a wide range of levels from strategy to support, to share a common view of the product or system being developed.

What you will learn

This guidebook will teach you how to use the rich features of Enterprise Architect to develop and manage Model Based Systems Engineering initiatives, to write and read the Systems Modeling Language (SysML), create documentation and to work collaboratively as a member of a team using a formal or informal engineering process.

You will learn what tool facilities are available and which tools should be used to perform a particular technique and using links to help topics how to use them . For example, regardless of the process or framework that is adopted, at some point Allocation between Structural and Behavioral elements will need to be performed; this topic will describe the technique and how to best achieve it using the tools and facilities you have at your fingertips by adopting Enterprise Architect.

Overview of the Documentation

This table provides a list and a description of the subjects that are included in this work, giving an overview of the material.

An Equation with Four Variables

This topic describes Model Based Systems Engineering from a mathematical perspective as an equation with four variables namely: Modeling, Enterprise Architect the tool of choice, the Systems modeling language, and an Engineering Process. Elementary mathematics would suggest that we need four simultaneous equations to solve such a problem. This topic will introduce these four variables and suggest ways you as an engineer or manager can  become proficient in this discipline without the need to solve the equations simultaneously.

We will see how Enterprise Architect can play an important part in all four parts of the equation and has been designed to help make your engineering initiatives successful.

Requirements Overview

Getting Started

This topic introduces newcomers to the tool to the most important aspects of the application, including setting up a model structure, tailoring the application, working with diagrams, other ways of visualizing content and integrations with other tools. It also includes discussions on the user interface, including Ribbons and Perspectives which are fundamental to working with the tool.

The tool has an extensive Help system that has been developed over more than twenty years and that can provide answers to almost any question that an engineer or other stakeholder might have while working in the tool.

Meet the Requirement Tools

Where we are Heading

This topic describes the list of the topics in the Guide, giving an overview of each topic.

Getting to Know the SysML Diagrams

This topic introduces the diagram as the preferred and most commonly used method for visualizing models and repository content. It gives a brief introduction to each diagram and allows the reader to build up a mental map of what the diagrams are and how that can be used both to express one's ideas and to interpret the ideas of others.

Systems Modeling Language Overview

This topic provides insight into the anatomy and the physiology of the Systems Modeling Language. It provides a useful synopsis of the notation and describes the language architecture. It also introduces the fundamental concepts including: Elements, Diagrams, Models and Views. While this information can be gleaned from the Specification itself it is summarized in this topic in enough detail to shield the newcomer from the need to wade through the specification.

Enterprise Architect provides example models and an extensive help system that will act as useful resources to help the newcomers and experienced practitioners alike gain experience with the language.

Additional Requirement Tools

Collaborating as an Engineering Team

This topic introduces the formidable collaboration tools where system engineers, managers, customers, consulting engineers, regulators and standards bodies can all contribute to models. This includes discussions, chats, model mail, a team library, reviews and more.

Using Packages to Structure the Repository

This topic covers the fundamental aspect of the repository structure and how it is used as an organizing principle to ensure that the repository is fit for purpose. It also covers how the Package can be used as a container that both allows content to be added but also provides a mechanism for the management of the elements, properties, diagrams and views that are added to each Package.

Requirements Definition and Management

This topic introduces the engineer and other stakeholders to this all important and central discipline that forms the basis for all other aspects of a modeling endeavor. Enterprise Architect has a formidable and unparalleled set of tools for developing, managing, visualizing and documenting requirements and these are introduced and practical examples are given on how the tool can be used.

Describing User Goals with Use Cases

This topic describes a user-centric way of articulating requirements where the goal that the user is trying to achieve is the foundation upon which a requirement is written. The users' goals are codified in Use Cases, which are represented simply on a diagram but the details of which are fleshed out in Enterprise Architect using the Scenario Builder. This facility allows the description, constraints such as preconditions and post-conditions, and the steps of the scenarios to be written in a compelling and productive user interface. It also describes how behavioral diagrams can be automatically generated from the tool, and the elements such as Activities can be linked to up-stream modeling elements such as Requirements and down-stream elements such as Components - creating effective and useful traceability.

Using Blocks to Model Structure and Constraints

The Block, which is introduced in this topic, is the fundamental unit of structure in the language and can also be used to model constraints. It is the atom of the SysML language and can have Features, Properties and Interaction Points that describe in detail the anatomy. This topic also describes the relationships that Blocks have with other model elements, including the all-important Allocation relationship that relates Blocks to Activities. Allocations tie together the two important pillars of the SysML: Structure and Behavior. It also introduces devices for modeling Quantity and Value Types that can be used to model dimensions in the physical world.

Using Properties and Parts to Model Block Usage

This topic follows on from the previous topic and introduces the Internal Block diagram, which is used to visualize how Blocks are used in a given context. These diagrams show how a Block's part properties can be connected together. The owning Block is represented as a diagram frame and the parts that appear at the part end of the Part Association on a Block Definition diagram appear on the Internal Block diagram as a Part element

Coordinating Behavior with Activities

This topic introduces Activities and the more atomic unit, the Action, which are both used to describe the behavioral aspects of a system at different levels. These all-important elements are equivalent to the verbs in our natural languages and, like verbs, have an organizing function in the model. Enterprise Architect has a number of useful devices such as Simulations that can bring these models to life and allow complex real world problems to be simplified and visualized.

Visualizing with Parametrics and Simulations

This topic explores the use of Parametric diagrams in connection with Block Definition diagrams, which define ConstraintBlocks that model mathematical equations and the parameters they use. The topic describes how these constraints and parameters can be represented on the Parametric diagram, which is a cousin of the Internal Block diagram. Simulation of the Parametric diagrams is also introduced and you will learn how to install and work with the OpenModelica interface. You will learn how advanced plots of equations can be visualized without the need to leave the Enterprise Architect environment.

Modeling Change with StateMachines

This topic introduces the StateMachine as a method of describing the discrete conditions (States) that an entity such as a Block can exhibit. This behavioral device can bring great clarity to a model and solve otherwise intractable problems. Enterprise Architect has a number of tool features that can bring these models to life, namely the State Table and Executable StateMachines that allow the States and the Transitions to be active in compelling visualizations.

Interactions as a Sequence of Messages

In this topic the Sequence diagram is introduced as a way of modeling messaged based behaviors. You will learn how to use this diagram to model a range of engineering concepts. The diagrams model the interaction between Blocks that are internal to the system, or between the system itself and its environment, and they can be used to model the communication that occurs with the steps of a Use Case. Lifelines and Activations are studied and Message orchestration is introduced with the use of Fragments.

A First Example SysML Model

In this topic we explore the diagrams that specify, design and test a Hybrid SUV vehicle that utilizes fuel and electricity as power sources, featuring mechanisms like regenerative breaking to meet its fuel efficiency requirements. The example model is published in an annex of the SysML specification; in this topic we explore the diagrams that have been created in Enterprise Architect, explaining significant language and tool features.

Meet the Systems Engineering Tools

This topic introduces some of the most important tools for working with Systems Engineering models, describing what they are, where they can be found, and how they can be used, including options and where to find more help. There are many other tools that modelers might find useful; these are introduced at relevant points in the document.