UML description of ROS simulation models

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UML description ofROS simulation models

• Report on work by
• Jos Vermeulen (NIKHEF),
• Bob Cranfield (UCL)

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Overview

• Recap of aims proposal
• Intro to UML with example diagrams
• Status of ROS model description
• Status of ROC model description
• Issues
• Next steps

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Aims

• The goal is a method for describing ROS
  simulation models that
• is not committed to a specific modelling tool
• can be readily used with Simdaq and Ptolemy
• is complete enough to include all ROS features
  that need to be modelled
• is accessible to the ROS team members so they can
  agree on the accuracy of the model
• Whole point is to find a common language in
  which the members of the team can discuss and
  evolve the model.

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UML

• Proposal is to use the UML (Unified Modelling
  Language)
• Widely used, including in ATLAS offline
• Designed to be easy to follow, with simple
  diagram notation
• Books tools available

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What is the model?

• Need to be careful with the term model
• A UML description is itself a model
• Our aim is to provide a UML model of a
  discrete-event model of the ROS
• i.e. NOT a UML model of
• the ROS
• the ROS software
• a Simdaq or Ptolemy implementation

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Note on tools

• Together 4.2
• free to academics
• multi-platform
• comprehensive diagramming
• used in ATLAS offline
• but memory hungry glitchy on Linux
• Source Navigator 4.5.2
• RedHat product
• convenient for reverse-engineering

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UML description

• A UML description is shown as a series of
  diagrams, of views of the system. Diagrams refer
  to the underlying UML model.
• UML has several types of diagram, some suited to
  real-time systems.
• The UML is object-oriented, but intended for a
  wide range of systems.
• UML diagrams are meant to be easy to follow

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UML diagrams

• use case diagram
• class diagram
• activity diagram
• object diagram
• sequence diagram
• collaboration diagram

• state diagram
• component diagram
• deployment diagram
• entity-relationship diagram
• business process diagram

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Class diagram

• The class diagram sets the context.
• It shows the classes of the system as boxes, with
  various linkages between.
• In Together classes are central elements, holding
  attributes operations.
• We need an object-oriented analysis of the
  significant features of the ROS to identify
  relevant elements of a class diagram.

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TRG (class diagram)
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Activity diagram

• The activity diagram shows the flow of logic
  within an operation.
• Key elements are activities (in rounded boxes)
  and conditional branches (diamonds).

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TRG_Task6 (activity diagram)
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Collaboration diagram

• The Collaboration diagram shows a snapshot of a
  set of objects, with the messages passing between
  them.
• The messages can be e.g. actual messages or
  method calls
• Messages initiate operations in the receiving
  objects

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TRG_Corbo (collaboration diagram)
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Sequence diagram

• The Sequence diagram is an alternative
  presentation of the information in a
  Collaboration diagram.
• It emphasises the time dimension, running
  vertically, and shows timing information.
• Together can automatically convert between
  Sequence and Collaboration diagrams.

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State diagram

• The State diagram is another way of describing
  the details of an operation.
• It shows a sub-system as a set of states, with
  transitions between them.
• It is probably more relevant to the
  implementation phase.

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TRG_Task6 (state diagram)
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ROS model

• Reverse engineering
• of ATDF code

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ROS default diagram
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TRG package
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ROB package
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ROB (class diagram)
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ROB_InTask (activity diagram)
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ROB_DCTask (activity diagram)
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ROB_TrgTask (activity diagram)
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ROB_TrgTask (sequence diagram)
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ROB_Local (collaboration diagram)
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EBIF package
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EBIF (class diagram)
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EBIF_Task1 (activity diagram)
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EBIF_Task2 (activity diagram)
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EBIF_Task3 (activity diagram)
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EBIF_Task4 (activity diagram)
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EBIF_OutStorage (collaboration diagram)
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IOM_sched package
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IOM_Sched (activity diagram)
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IOM_Sched (collaboration diagram)
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default (class diagram)
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ROC model

• Reverse engineering of
• Bertram Renschs Ptolemy code

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ROC Class diagram
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ROC full Collaboration diagram
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DETRG Activity diagram
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DEXpci Activity diagram
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Open issues

• Naming of attributes operations
• Representation of i/o channels
• Indication of time-consuming operations
• Naming convention for diagrams
• Maintenance of sub-set diagrams

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Next steps

• Complete first-draft activity, collaboration,
  sequence diagrams
• Check diagrams with ROS team
• Add diagrams for different ROS variants
• Add diagrams for hardware elements