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Telescope Modeling Challenge Team

Purpose

In an effort to further promote the INCOSE/OMG Model-Based Systems Engineering (MBSE) Initiative, a next generation Telescope Modeling Challenge Team has been convened to investigate the applicability of MBSE to specifying, analyzing, designing, and verifying systems in the telescope domain. As part of the INCOSE SE Transformation, a strategic objective is to accelerate the transformation of systems engineering to a model-based discipline. The Telescope Modeling Challenge Team is driven to accomplish this goal by studying how telescope models interact throughout the system life cycle to best achieve the desired science cases set forth by stakeholders, while enabling the highest engineering capabilities to model real-world solutions.

In 2007, the European Southern Observatory (ESO) and the German Chapter of INCOSE (GfSE) joined to form the first generation Telescope MBSE Challenge Team, SE2. Their work can be found here: Telescope Modeling Challenge Team SE2. The second generation Telescope Modeling Challenge Team expands on the work and efforts from SE2.

Measure of Success

Our team will produce a new revision to the Cookbook for MBSE with SysML to provide system modelers with recipes and best practices for common modeling problems. Success of this Cookbook will be seen in the adoption of MBSE across the telescope community, including increased MBSE collaboration across projects and a trend toward organizational adoption of MBSE methods, as well as its utility to accelerate the development of telescope systems in varying stages of the system life cycle. System modelers will be able to make their models available for use across multiple domains, and their effectiveness will be measured by user feedback and system development improvements. Success will also be measured by examples of SysML challenges and lessons learned applied to real projects, as well as tool enhancements and improved ROI demonstrated by the use of these MBSE tools.

MBSE Challenge Goals

SysML is a graphical modeling language that provides semantics and notation (meaning and representations) to support the specifications, analysis, design, verification, and validation of complex systems. SysML is not a tool or methodology. The language is intended to support the specification and architecture of systems , and like many formal or informal languages it can be represented and applied in many different ways.

The next generation Telescope Modeling Challenge Team will continue to use SysML to facilitate the application of MBSE to systems engineering practices.

Primary goals for the Telescope Modeling Challenge Team are to:

  • Unordered List ItemProvide examples of SysML common modeling problems and best resolution approaches
  • Unordered List ItemDemonstrate that SysML is an effective means to support requirements engineering and management of complex systems throughout the development life cycle
  • Unordered List ItemDemonstrate the benefits of SysML models as the basis for integrated engineering and analyses

The new revision of the Cookbook for MBSE with SysML will provide the latest updates to MBSE challenges, goals, and lessons learned as the team continues its mission to promote telescope modeling for real-world applications. The presentation, Telescope Modeling with SysML, provides an overview of the previous results from SE2, and the current challenges and goals for the next generation Telescope Modeling Challenge Team.

Adopters of MBSE at different telescope projects

Collaboration

Case Studies

Schedule

DateMilestoneStatusPoint of Contact

Webinars

DateTopicWho

SE2 Team Members

NameOrganizationContact Information
Robert Karban (lead) ESOrobert.karban@incose.org
Tim Weilkiens oose GmbHtim.weilkiens@incose.org
Rudolf Hauber
Berthil Muth HOOD Groupberthil.muth@hood-group.com
Rainer Diekmann Consultant Rainer.Diekmann@hamburg.de
Michele Zamparelli ESOmzampare@eso.org
Andreas Hein TUMA.Hein@lrt.mw.tum.de
Christian Zingel IPEK – Institut für Produktentwicklungchristian.zingel@kit.edu

Methodology

SysML is a language and does not prescribe any methodology. For example, SysML allows to use the «allocate» relationship between nearly any model element. But where is this feature useful in a specific project? How can the relationship be determined from the model, e.g. for traceability? What are the consequences of having an «allocate» relationship between two elements? You do not find answers to these questions in the SysML specification.

SE2 did not define a MBSE methodology. The modeling work is based on different existing methodologies like SYSMOD, OOSEM, or Wymore´s MBSE theory. The Challenge Team has found some best practices and modeling guidelines to complement them but each project needs its own specific set of methods (see the Survey of Methodologies for more information). The results are supposed to be mostly method independent.

Achievements

You find a complete version of the model and other material like presentations on our website: Telescope and Space Systems Modeling Challenge Teams.

Major problems addressed

  • Use properly SysML language and its elements to represent a system
    • Representative model
    • Practices and guidelines
  • Scalable model organization
  • Reuse of blocks (catalog)
  • Modeling challenges
    • Identified and provided feed back to OMG´s Revision Task Force (RTF) Working Groups
    • Notation (e.g. Connection of nested blocks)
    • Modeling technicalities (e.g. Grouping of interfaces, Variant modeling)
    • Tool (e.g. Configuration and Quality Control)
  • Methodology (e.g. multi-layer allocation)
  • Feed back to vendor for improvement of tool
  • And many more smaller problems (see Cookbook)

Modeling challenges

SysML is a new language. This creates two inherent challenges: Is SysML sufficiently mature for real projects and is it accepted by a wide range of systems engineers? Especially the fact that SysML is based on UML sheds a special light on these challenges. Could a modeling language, which was initially defined for software development, be used to model systems and will systems engineers accept a language with origins in the software discipline? An overall result of our project is, that this question can be answered with yes.

The APE project is a pretty good challenge for SysML. It is complex, interdisciplinary without a special focus on software; it is a real system and no simplified coffee machine as often used as demonstration project. Although we found that SysML is practicable to model complex systems, we have found a list of SysML shortcomings.

The most significant ones are:

  • Variant modeling
  • Connection of nested blocks
  • Grouping of interfaces with nested ports
  • Logical vs. Physical decomposition
  • Functional multi-layer abstraction
  • Reuse of blocks, allocation and instances
  • Structural multi-layer allocation
  • Defining Quality of Service
  • Transition to UML for software
  • Configuration and Quality Control
  • Navigability
  • Modelling Frames of Reference and Coordinate Systems
  • Modelling Work Breakdown Structures

Cookbook for MBSE with SysML

The Cookbook addresses a variety of modeling areas, illustrated with real world examples.

 APE Junction Box Interface APE electrical view
  • Style and Layout
  • Model Organization
  • System Aspects and Views
  • Requirements and Use Case modeling
  • Structure Modeling
  • Behavior Modeling
  • Interface Modeling
  • Guidelines for Modeling Non-Functional Aspects
  • Integration with other Disciplines
  • Variant Modeling
  • Cross-cutting the Model and Traceability
  • Constraint Modeling
  • Ontologies
  • Metrics
  • Model Based Document Generation
  • Boilerplates for Requirements
  • Modeling reusable Parts in a Catalog
  • SE Profile, Customization, and Meta-Modeling

Online Model

The APE SysML Model provides the complete model navigable online in any web-browser.

Readings

From the SE2 Readings section you can download most given presentations and published papers related to MBSE and SysML by the SE2 Challenge team members.

Downloads

In Downloads section you will find the complete model in MagicDraw´s mdzip format as well as the Open-Source MBSE Plugin for the modelling tool, which helps in querying the model, create automatically basic organizational structure, extracts model variants, and supports model based document generation based on DocBook.

Wiki Articles

Model Based Document Generation

The document is modeled in the same model as the system, using UML/SysML elements. A subset of the DocBook markup language is mapped to stereotypes, and applied to UML/SysML model elements, e.g. chapter to package, paragraph to comment. The MBSE plug-in which you can download from this site creates a DocBook file from the model. Note, that it is just a proof of concept with limitations. For example, only a limited number of DocBook elements are supported but sufficient to make reasonable use of it.

The plug-in can be downloaded here: MBSE Plugin.

The advantages are manifold

  • consistent integration of system model and system documentation
  • direct linking to model elements (also diagrams) from the document
  • changes of diagram names is automatically reflected in the document
  • using proper definition of the stereotype associations only compatible elements can be selected to compose the document, e.g. a figure references diagrams, a chapter references paragraphs.
  • the documentation is at the same time navigable in the model and printable
  • documents are modeled in a tool independent way. Only a small plug-in is needed to generate DocBook XML.

There are also disadvantages (which we hope will be solved by tool vendors in the future…)

  • which subset of DocBook should be supported?
  • creating cross-references (also internal ones) is possible but a bit cumbersome
  • comments are elements without a name and therefore a bit difficult to find in the model browser
  • MagicDraw's text editor supports only HTML which is not compliant with DocBook and the text has to be transformed (which is done automatically when generating)

Model Execution

This section will contain progress on Model Execution of SysML models.

References

mbse/telescope.1487988119.txt.gz · Last modified: 2017/02/25 02:01 by acrawford