SysML in Action with Cameo Systems Modeler

Olivier Casse

• Publisher: ISTE Press - Elsevier
• Year: 2017
• Print ISBN: 9781785481710
• eBook ISBN: 9780081017739
• Topic: Computer Science
• Subtopic: Hardware
• Index: Computer Science

System engineering (SE) using models (MBSE) is currently in vogue in the community of SE practitioners, whether they are analysts, architects, developers or testers. INCOSE has contributed greatly to the definition of a language for the community, henceforth standardized under ISO-19514: SysML. However, this language is not associated by default with any particular MBSE procedure. This is a major difficulty hampering its implementation.In order to overcome this difficulty, this book describes, in addition to the SysML notation, a generic approach based on the main principles of SE and relative standards, serving as the basis for a specific MBSE approach to be built. This is in order to respond to the specificities of the field of projects in which the practitioners evolve. In order to carry out the procedure in a pragmatic way, a simplified but realistic example serves as a guideline from the initial requirements to the validation of the system, putting into action the SysML modeling tool Cameo Systems Modeler by No Magic.- Based on a realistic example and simplified, yet still useful for professionals (no ATM or traffic lights)- Explores everything from requirements to validation to cover the classical V cycle- Utilizes a generic approach, fully suitable to SysML, to apply major system engineering principles and standards- Helps users learn to make their own model by transcribing their needs and taking advantage of the tool features, - Conserves time by using recommended workarounds to develop custom processes for this tool, before deploying successfully on real industrial projects

1

SysML: Object Management Group (OMG) Systems Modeling Language

Abstract

SysML is the result of a desire to establish a modeling language common to the stakeholders in a complex project of system engineering as of January 2001. Previous available approaches had great disparity, that is to the level of the languages and the tools, not promoting communication, maintenance etc.

Keywords

Activity diagram Fragment; Labels/tags; Model-based systems engineering; Pseudo-states; State machine diagram; Stereotypes; SysML; Use case diagram; V cycle

1.1 Background

SysML is the result of a desire to establish a modeling language common to the stakeholders in a complex project of system engineering as of January 2001. Previous available approaches had great disparity, that is to the level of the languages and the tools, not promoting communication, maintenance etc.

Moreover, the Unified Modeling Language (UML) language, which had already been available at the time for over several years, was accessible on a large number of modeling tools. Some projects have tried to use UML as a means of system modeling. Unfortunately, its strong computing connotation and the lack of certain concepts (traceability of requirements for example) were a hindrance to the success of UML in Systems Engineering.

A consortium consisting of mainly American and European members has been created within the OMG with industrialists, mainly in the field of space and aeronautics, tool publishers, as well as academic organizations or groups of experts in the field, including the International Council on Systems Engineering (INCOSE), which we will discuss later.

Figure 1.1 Official logo of OMG SysML. For a color version of this figure, see www.iste.co.uk/casse/sysml.zip

1.2 What is SysML?

SysML is a modeling language consisting of a toolbox offering several ways to describe a complex system. SysML also proposes, in a Model-Based Systems Engineering (MBSE) framework, documenting a system from different points of view or perspectives, in order to make the description accessible to target readers.

SysML is not a method, no specific approach is proposed by the OMG for its implementation.

SysML reuses a subset of UML 2 and extends it to address the additional requirements of system engineering.

Figure 1.2 SysML is both a subset and an extension of UML 2

The part of UML reused for SysML is generally known as UML4SYSML.

We will see that many UML2 diagrams are repeated without any changes, or with few minor additions, which was one of the objectives of the OMG whereby tool publishers proposed a modeler that facilitated modifications; all SysML modeling tools are indeed based on a UML core, specialized for SysML through a dedicated profile.

The version of SysML described in this book is V1.5, which was the official version at the time of the publication of this book.

1.3 System Engineering in a nutshell

We will focus solely on aspects related to SysML, voluntarily omitting the other aspects (economic, commercial, regulatory, etc.), since they are beyond the context of this book.

System engineering is a multidisciplinary approach designed to enable the production of successful systems.

Figure 1.3 Product Lifecycle

This approach focuses on defining the customer needs and the functionalities necessary for the proper functioning of a system. These needs and expectations must be validated as early as possible in the development cycle, documenting the requirements and then carrying out the design and validation of the system, taking into account the whole topic to be covered: operational aspects, performance, testability, manufacturing constraints, costs and delays, training and support and ultimately disposal.

Several standards govern good Systems Engineering practices, in particular IEEE-15288, as well as EIA 632 and IEEE 1220. The main reference will be to IEEE-15288, for example highlighting these few key steps:

– specifications, interviews and customer requirements;

– defining the stakeholder need process;

– technical specifications;

– requirements analysis;

– definition of the preliminary system;

– design process.

1.4 Advantages of System Engineering

The following is a non-exhaustive list of the main benefits of using a system engineering approach. First, complying with the requirements given for a product ensures an increase in quality by implementing the verification and validation principle as early as possible. Then, mastering the complexity, through modeling and simulation, the decomposition of the system serving as a common basis for the development of the system (single and unified platform), exchanges and collaborative work.

Some advantages also derive from the ...

Table of contents

• Cover
• Title page
• Table of Contents
• Copyright
• Foreword
• Preface
• 1: SysML: Object Management Group (OMG) Systems Modeling Language
• 2: About Cameo Systems Modeler
• 3: Example
• 4: Case Study
• 5: Beyond Modeling
• Glossary
• Bibliography
• Index