ISO/IEC 15909-3:2021

INTERNATIONAL ISO/IEC
STANDARD 15909-3
First edition
2021-11
Systems and software engineering —
High-level Petri nets —
Part 3:
Extensions and structuring
mechanisms
Ingénierie du logiciel et des systèmes — Réseaux de Petri de haut
niveau —
Partie 3: Extensions et mécanismes de structuration
Reference number
© ISO/IEC 2021
© ISO/IEC 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
© ISO/IEC 2021 – All rights reserved

Contents Page
Foreword .v
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Conformance . 2
4.1 General . 2
4.2 Enrichment process . 2
4.3 Extension process . 2
4.4 Structuring mechanism . 3
5 Enrichment process .3
5.1 General . 3
5.2 Instances of enrichment . 3
5.2.1 General . 3
5.2.2 Inhibitor arcs . 3
5.2.3 Reset arcs . 4
5.2.4 Read arcs . 4
5.2.5 Capacity places . 5
5.3 Generalized enrichment process . 5
5.3.1 General . 5
5.3.2 Definition of Petri nets with enrichment . 5
5.3.3 Definition of enabling rule for Petri nets with enrichment . 6
5.3.4 Filtering function for enrichment . 6
5.3.5 Firing rule for Petri nets with enrichment . 6
5.3.6 Compatibility with extensions . 6
6 Extension process . 6
6.1 General . 6
6.2 An instance of extension: FIFO nets . 6
6.2.1 General . 6
6.2.2 Definition of FIFO nets . 7
6.2.3 Behavioural semantics . 7
6.2.4 Definition of equivalent high-level Petri net . 7
6.2.5 Compatibility with enrichments . 7
6.3 The generalized extension process . 7
6.3.1 General . 7
6.3.2 Definition of the net type . 8
6.3.3 Definition of the behavioural semantics . 8
7 Structuring mechanism.8
7.1 General . 8
7.2 Module definition . 8
7.2.1 Definition of sort generator . 8
7.2.2 Definition of module interface . 9
7.2.3 Definition of module implementation . 9
7.3 Module instantiation . 9
7.3.1 General . 9
7.3.2 Definition of module instances and uses . 9
7.3.3 Definition of module definition . 10
7.3.4 Definition of signature and homomorphisms σ . 11
k
7.3.5 Definition of variables . 11
7.3.6 Definition of algebra .12
iii
© ISO/IEC 2021 – All rights reserved

ˆ
7.3.7 Definition of places and transitions T .12
Annex A (informative) Guidelines for graphical notations .13
Bibliography .15
iv
© ISO/IEC 2021 – All rights reserved

Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are
members of ISO or IEC participate in the development of International Standards through technical
committees established by the respective organization to deal with particular fields of technical
activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international
organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the
work.
The procedures used to develop this document and those intended for its further maintenance
are described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria
needed for the different types of document should be noted. This document was drafted in
accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives or
www.iec.ch/members_experts/refdocs).
Attention is drawn to the possibility that some of the elements of this document may be the subject
of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent
rights. Details of any patent rights identified during the development of the document will be in the
Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC
list of patent declarations received (see patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to
the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see
www.iso.org/iso/foreword.html. In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 7, Software and systems engineering.
A list of all parts in the ISO/IEC 15909 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
v
© ISO/IEC 2021 – All rights reserved

Introduction
Petri nets have been used to describe a wide range of systems since their invention in 1962. The
technique is mathematically defined and can thus be used to provide unambiguous specifications
and descriptions of applications. It is also an executable technique, allowing specification prototypes
to be developed to test ideas at the earliest and cheapest opportunity. Specifications written in the
technique can be subjected to analysis methods to prove properties about the specifications, before
implementation commences, thus saving on testing and maintenance time and providing a high level of
quality assurance.
A problem with Petri nets is the explosion of the number of elements in their graphical form when they
are used to describe complex systems. High-level Petri nets were developed to overcome this problem
by introducing higher level concepts, such as the use of complex structured data as tokens, and using
algebraic expressions to annotate net elements. The
...