Modelica_StateGraph2.UsersGuide Modelica_StateGraph2.UsersGuide


Library Modelica_StateGraph2 is a free Modelica package providing components to model discrete event and reactive systems in a convenient way. This package contains the User's Guide for the library and has the following content:

  1. "Tutorial" gives an overview of the most important aspects of the StateGraph2 library.
  2. "Comparison with StateGraph1" explains the significant enhancements with respect to the previous Modelica.StateGraph version.
  3. "Release Notes" summarizes the differences between different versions of this library.
  4. "Literature" provides references that have been used to design and implement this library.
  5. "Used Modelica Extensions" summarizes the non-standard extensions used by this library.
  6. "Modelica License 2" is the license under which this package and all of its subpackages is released.
  7. "Contact" provides information about the authors of the library as well as acknowledgments.

Package Content

NameDescription
Modelica_StateGraph2.UsersGuide.Tutorial Tutorial Tutorial
Modelica_StateGraph2.UsersGuide.ComparisonWithStateGraph1 ComparisonWithStateGraph1 Comparison with StateGraph1
Modelica_StateGraph2.UsersGuide.ReleaseNotes ReleaseNotes Release notes
Modelica_StateGraph2.UsersGuide.Literature Literature Literature
Modelica_StateGraph2.UsersGuide.UsedModelicaExtensions UsedModelicaExtensions Used Modelica Extensions
Modelica_StateGraph2.UsersGuide.ModelicaLicense2 ModelicaLicense2 Modelica License 2
Modelica_StateGraph2.UsersGuide.Contact Contact Contact


Modelica_StateGraph2.UsersGuide.ComparisonWithStateGraph1 Modelica_StateGraph2.UsersGuide.ComparisonWithStateGraph1


The Modelica_StateGraph2 library (called StateGraph2 below) is based on the experience with the current Modelica.StateGraph library (called StateGraph1 below) and is a significantly further development of StateGraph1. Furthermore, it is heavily based on the article (Malmheden et. al. 2008), see literature, but uses a different implementation technique as described in this article. The StateGraph2 library has the following improvements with respect to the StateGraph1 library:


Modelica_StateGraph2.UsersGuide.ReleaseNotes Modelica_StateGraph2.UsersGuide.ReleaseNotes


Version 2.0.1, 2010-11-08

Uses Modelica Standard Library 3.2

Version 2.0, 2009-08-10

First version of the Modelica_StateGraph2 library based on Modelica.StateGraph and the prototype ModeGraph library from Martin Malmheden. The changes with respect to Modelica.StateGraph (version 1) are summarized here.


Modelica_StateGraph2.UsersGuide.Literature Modelica_StateGraph2.UsersGuide.Literature


The Modelica_StateGraph2 library is described in detail in (Otter et. al. 2009, see below) and is additionally based on the following references:

André, C. (2003):
Semantics of S.S.M (Safe State Machine).. I3S Laboratory, UMR 6070 University of Nice-Sophia Antipolis / CNRS.
 
Arzen K.-E. (2004):
JGrafchart User Manual. Version 1.5. Department of Automatic Control, Lund Institute of Technology, Lund, Sweden, Feb. 13, 2004.
 
Dressler I. (2004):
Code Generation From JGrafchart to Modelica.. Master thesis, supervisor: Karl-Erik Arzen, Department of Automatic Control, Lund Institute of Technology, Lund, Sweden, March 30, 2004.
 
Elmqvist H., Mattsson S.E., Otter M. (2001):
Object-Oriented and Hybrid Modeling in Modelica. Journal Europeen des systemes automatises (JESA), Volume 35 - n. 1, 2001.
 
Harel, D. (1987):
A Visual Formalism for Complex Systems. Science of Computer Programming 8, 231-274. Department of Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel.
 
Malmheden M. (2007):
ModeGraph - A Mode-Automata-Based Modelica Library for Embedded Control. Master thesis, Department of Automatic Control, Lund University, Sweden.
 
Malmheden M., Elmqvist H., Mattsson S.E., Henrisson D., Otter M. (2008):
ModeGraph - A Modelica Library for Embedded Control based on Mode-Automata. Modelica'2008 Conference, March 3-4, 2008.
 
Maraninchi F., Rémond, Y. (2002):
Mode-Automata: A New Domain-Specific Construct for the Development of Safe Critical Systems.
 
Mosterman P., Otter M., Elmqvist H. (1998):
Modeling Petri Nets as Local Constraint Equations for Hybrid Systems using Modelica. SCSC'98, Reno, Nevada, USA, Society for Computer Simulation International, pp. 314-319, 1998.
 
Otter M., Malmheden M., Elmqvist H., Mattsson S.E., Johnsson C. (2009):
A New Formalism for Modeling of Reactive and Hybrid Systems. Modelica'2009 Conference, Como, Italy, Sept. 20-22, 2009.


Modelica_StateGraph2.UsersGuide.UsedModelicaExtensions Modelica_StateGraph2.UsersGuide.UsedModelicaExtensions


This library is implemented with the Modelica 3.1 language. Additionally, some extensions to the Modelica language are used, in order to guarantee that only valid StateGraph2 graphs are accepted by a Modelica tool. It is planned to introduce these new language elements into the next version 3.2 of the Modelica language. This means, only Modelica tools will be able to process this Modelica_StateGraph2 package, if the following (non-standard) extensions of Modelica are supported:

Connection Graphs for State Diagrams (new section 9.4.2)

In order that a Modelica translator can guarantee the connection structure of hierarchical state diagrams, some additional operators are needed for the virtual connection graph. This special virtual connection graph is called "virtual state diagram graph" in the sequel. Virtual state diagram graphs are undirected graphs having overdetermined type or record instances as nodes. The branches are defined by connect(..) and by Connections.branch(..) statements. With the new operators Connections.uniqueRoot(..) and Connections.uniqueRootIndices(..) restrictions to the graph are introduced, as defined in the following table. If one node of a virtual connection graph is marked with uniqueRoot(..), then a virtual state diagram graph is present and it is not allowed to apply the operators Connections.root(..), Connections.potentialRoot, or Connections.isRoot(..) on a node of this graph.


Modelica_StateGraph2.UsersGuide.ModelicaLicense2 Modelica_StateGraph2.UsersGuide.ModelicaLicense2


All files in this directory (Modelica) and in all subdirectories, especially all files that build package "Modelica_StateGraph2" and all files in Modelica\Images are licensed by DLR and Dynasim under the Modelica License 2


The Modelica License 2

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Licensed by DLR and Dynasim under the Modelica License 2

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Frequently Asked Questions

This section contains questions/answer to users and/or distributors of Modelica packages and/or documents under Modelica License 2. Note, the answers to the questions below are not a legal interpretation of the Modelica License 2. In case of a conflict, the language of the license shall prevail.


Using or Distributing a Modelica Package under the Modelica License 2

What are the main differences to the previous version of the Modelica License?

  1. Modelica License 1 is unclear whether the licensed Modelica package can be distributed under a different license. Version 2 explicitly allows that “Derivative Work” can be distributed under any license of Your choice, see examples in Section 1d) as to what qualifies as Derivative Work (so, version 2 is clearer).

  2. If You modify a Modelica package under Modelica License 2 (besides fixing of errors, adding vendor specific Modelica annotations, using a subset of the classes of a Modelica package, or using another representation, e.g., a binary representation), you must rename the root-level name of the package for your distribution. In version 1 you could keep the name (so, version 2 is more restrictive). The reason of this restriction is to reduce the risk that Modelica packages are available that have identical names, but different functionality.

  3. Modelica License 1 states that “It is not allowed to charge a fee for the original version or a modified version of the software, besides a reasonable fee for distribution and support“. Version 2 has a similar intention for all Original Work under Modelica License 2 (to remain free of charge and open source) but states this more clearly as “No fee, neither as a copyright-license fee, nor as a selling fee for the copy as such may be charged”. Contrary to version 1, Modelica License 2 has no restrictions on fees for Derivative Work that is provided under a different license (so, version 2 is clearer and has fewer restrictions).

  4. Modelica License 2 introduces several useful provisions for the licensee (articles 5, 6, 12), and for the licensor (articles 7, 12, 13, 14) that have no counter part in version 1.

  5. Modelica License 2 can be applied to all type of work, including documents, images and data files, contrary to version 1 that was dedicated for software only (so, version 2 is more general).

Can I distribute a Modelica package (under Modelica License 2) as part of my commercial Modelica modeling and simulation environment?

Yes, according to Section 2c). However, you are not allowed to charge a fee for this part of your environment. Of course, you can charge for your part of the environment.

Can I distribute a Modelica package (under Modelica License 2) under a different license?

No. The license of an unmodified Modelica package cannot be changed according to Sections 2c) and 2d). This means that you cannot sell copies of it, any distribution has to be free of charge.

Can I distribute a Modelica package (under Modelica License 2) under a different license when I first encrypt the package?

No. Merely encrypting a package does not qualify for Derivative Work and therefore the encrypted package has to stay under Modelica License 2.

Can I distribute a Modelica package (under Modelica License 2) under a different license when I first add classes to the package?

No. The package itself remains unmodified, i.e., it is Original Work, and therefore the license for this part must remain under Modelica License 2. The newly added classes can be, however, under a different license.

Can I copy a class out of a Modelica package (under Modelica License 2) and include it unmodified in a Modelica package under a commercial/proprietary license?

No, according to article 2c). However, you can include model, block, function, package, record and connector classes in your Modelica package under Modelica License 2. This means that your Modelica package could be under a commercial/proprietary license, but one or more classes of it are under Modelica License 2.
Note, a “type” class (e.g., type Angle = Real(unit=”rad”)) can be copied and included unmodified under a commercial/proprietary license (for details, see the next question).

Can I copy a type class or part of a model, block, function, record, connector class, out of a Modelica package (under Modelica License 2) and include it modified or unmodified in a Modelica package under a commercial/proprietary license

Yes, according to article 2d), since this will in the end usually qualify as Derivative Work. The reasoning is the following: A type class or part of another class (e.g., an equation, a declaration, part of a class description) cannot be utilized “by its own”. In order to make this “usable”, you have to add additional code in order that the class can be utilized. This is therefore usually Derivative Work and Derivative Work can be provided under a different license. Note, this only holds, if the additional code introduced is sufficient to qualify for Derivative Work. Merely, just copying a class and changing, say, one character in the documentation of this class would be no Derivative Work and therefore the copied code would have to stay under Modelica License 2.

Can I copy a class out of a Modelica package (under Modelica License 2) and include it in modified form in a commercial/proprietary Modelica package?

Yes. If the modification can be seen as a “Derivative Work”, you can place it under your commercial/proprietary license. If the modification does not qualify as “Derivative Work” (e.g., bug fixes, vendor specific annotations), it must remain under Modelica License 2. This means that your Modelica package could be under a commercial/proprietary license, but one or more parts of it are under Modelica License 2.

Can I distribute a “save total model” under my commercial/proprietary license, even if classes under Modelica License 2 are included?

Your classes of the “save total model” can be distributed under your commercial/proprietary license, but the classes under Modelica License 2 must remain under Modelica License 2. This means you can distribute a “save total model”, but some parts might be under Modelica License 2.

Can I distribute a Modelica package (under Modelica License 2) in encrypted form?

Yes. Note, if the encryption does not allow “copying” of classes (in to unencrypted Modelica source code), you have to send the Modelica source code of this package to your customer, if he/she wishes it, according to article 6.

Can I distribute an executable under my commercial/proprietary license, if the model from which the executable is generated uses models from a Modelica package under Modelica License 2?

Yes, according to article 2d), since this is seen as Derivative Work. The reasoning is the following: An executable allows the simulation of a concrete model, whereas models from a Modelica package (without pre-processing, translation, tool run-time library) are not able to be simulated without tool support. By the processing of the tool and by its run-time libraries, significant new functionality is added (a model can be simulated whereas previously it could not be simulated) and functionality available in the package is removed (e.g., to build up a new model by dragging components of the package is no longer possible with the executable).

Is my modification to a Modelica package (under Modelica License 2) a Derivative Work?

It is not possible to give a general answer to it. To be regarded as "an original work of authorship", a derivative work must be different enough from the original or must contain a substantial amount of new material. Making minor changes or additions of little substance to a preexisting work will not qualify the work as a new version for such purposes.


Using or Distributing a Modelica Document under the Modelica License 2

This section is devoted especially for the following applications:

  1. A Modelica tool extracts information out of a Modelica package and presents the result in form of a “manual” for this package in, e.g., html, doc, or pdf format.

  2. The Modelica language specification is a document defining the Modelica language. It will be licensed under Modelica License 2.

  3. Someone writes a book about the Modelica language and/or Modelica packages and uses information which is available in the Modelica language specification and/or the corresponding Modelica package.

Can I sell a manual that was basically derived by extracting information automatically from a Modelica package under Modelica License 2 (e.g., a “reference guide” of the Modelica Standard Library):

Yes. Extracting information from a Modelica package, and providing it in a human readable, suitable format, like html, doc or pdf format, where the content is significantly modified (e.g. tables with interface information are constructed from the declarations of the public variables) qualifies as Derivative Work and there are no restrictions to charge a fee for Derivative Work under alternative 2d).

Can I copy a text passage out of a Modelica document (under Modelica License 2) and use it unmodified in my document (e.g. the Modelica syntax description in the Modelica Specification)?

Yes. In case you distribute your document, the copied parts are still under Modelica License 2 and you are not allowed to charge a license fee for this part. You can, of course, charge a fee for the rest of your document.

Can I copy a text passage out of a Modelica document (under Modelica License 2) and use it in modified form in my document?

Yes, the creation of Derivative Works is allowed. In case the content is significantly modified this qualifies as Derivative Work and there are no restrictions to charge a fee for Derivative Work under alternative 2d).

Can I sell a printed version of a Modelica document (under Modelica License 2), e.g., the Modelica Language Specification?

No, if you are not the copyright-holder, since article 2c) does not allow a selling fee for a (in this case physical) copy. However, mere printing and shipping costs may be recovered.


Modelica_StateGraph2.UsersGuide.Contact Modelica_StateGraph2.UsersGuide.Contact


Main Authors:
Martin Otter
Deutsches Zentrum für Luft und Raumfahrt e.V. (DLR)
Institut für Robotik und Mechatronik
Abteilung für Systemdynamik und Regelungstechnik
Postfach 1116
D-82230 Wessling
Germany
email: Martin.Otter@dlr.de
  and   Martin Malmheden and Hilding Elmqvist
Dynasim AB (a Dassault Systèmes company)
Ideon Science Park
SE-223 70 Lund
Sweden
email: Martin.Malmheden@3ds.com

Acknowledgements:

This library is based on the Modelica.StateGraph library and therefore the acknowledgement of the StateGraph library is repeated here:

The Modelica_StateGraph2 library is based on further ideas developed in (Malmheden et.al., 2008), see literature, and the prototype ModeGraph library developed by Martin Malmheden during his master thesis and for this article.

Partial financial support of DLR by BMBF (BMBF Förderkennzeichen: 01IS07022F) for the development of the Modelica_StateGraph2 library within the ITEA2 project EUROSYSLIB is highly appreciated.


Automatically generated Fri Nov 12 17:26:46 2010.