Kristian Bisgaard Lassen / Simon TjellDep. of Comp. Science, University of Aarhus, Denmark

Developing Tool Support for Problem Diagrams with

CPN and VDM++

Outline

An example of a problem Coloured Petri Nets (CPN) Problem Diagrams Walk through a typical workflow Future work

Coloured Petri Nets (CPN) A graphical modeling language A high-level extension to Petri Nets adding:

Complex data types for tokens A functional language for token manipulation/examination Hierachical constructs Time (delays, timestamps)

Tool support: Graphical editing Simulation by execution State space analysis

Sluice Gate Controller

S

S

Sluice GateController

M

Operator

PD1

Problem Diagrams (1)

Gate &Motor

a: SC! {Direction, Control}GM! {Sensors}

b: GM! {Position, Movement}c: SO! {Buttons}

SluiceOperator

Sluice GateController

Control Gate

c

a b

c

Machine

ContextDomains

Requirement SharedPhenomena

Problem Diagrams (2)

Problem Diagrams: Identify relevant entities in the near environment Identify knowledge about structure in the

environment Identify shared phenomena (~interaction

channels) Do not describe behavior Can be used to document Problem

Decomposition

PD2

Problem Diagrams (3)

a: TC! {Direction, Control}GM! {Sensors}

b': GM! {Position}

a b'TimedController

Gate &Motor

Open Periodically

PD1

PD1

PD2

PD3

Problem Diagrams (4)

a: MC! {Direction, Control}GM! {Sensors}

b: GM! {Position, Movement}c: SO! {Buttons}

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

PD3

Translate

Automatically generates a composite CPN model

Contents:● a module per context domain in the PD● a machine module● a link module

● enables communication through shared phenomena (only)● preserves the structure of the PD● records traces of phenomena activity

● a requirement module

Behavior of context and machine domains is initially free/spontaneous

Translating

PD1

PD2

PD3

PD3

Export

PD3

Translate

Automatically write an XML representation of the composite CPN model● Structure (modules and connections)● Data types● Functions

Exporting (1)

PD1

PD2

PD3

PD3

Export

PD3

Translate

PD3

Exporting (2)PD1

PD2

PD1

PD2

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

Gate & Motor

PD3

Export

PD3

Translate

PD3

Exporting (3)PD1

PD2

PD1

PD2

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

Link module

c

PD3

Export

PD3

Translate

PD3

Exporting (4)PD1

PD2

PD1

PD2

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

Requirement module

PD3

Export

PD3

Translate

PD3

Modifying (1)PD1

PD2

PD1

PD2

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

Modify

CPN Tools

PD3

Export

PD3

Translate

PD3

Modifying (2)PD1

PD2

PD1

PD2

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

Modify

Automatically generated phenomena color sets (data types):colset Value_Buttons = bool;colset Value_Control = bool;colset Value_Sensors = bool;colset Value_Movement = bool;colset Value_Position = bool;colset Value_Direction = bool;

+ color sets for states, events, traces, timestamps etc.(need no manual modification)

Manually modified:colset Value_Buttons = unit;colset Value_Control = with On | Off;colset Value_Sensors = product BOOL * BOOL;colset Value_Movement = with Raising | Falling | Stopped;colset Value_Position = with Top | Between | Bottom;colset Value_Direction = with Up | Down;

PD1

PD2

PD3

Importing

PD3

Export

PD3

Translate

Modify

Translate

PD2

a b'TimedController

Gate &Motor

Open Periodically

Import

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

Translate

Import

PD3

Modify

PD1

PD2

PD3

Combining (1)

Export

PD3

Translate

PD2

a b'TimedController

Gate &Motor

Open Periodically

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

Combine

Prerequisities (to PD3):

●Valid structure (wrt. PD)●No conflicting modules●No interface extension

Translate

Import

PD3

Modify

PD1

PD2

PD3

Combining (2)

Export

PD3

Translate

PD2

a b'TimedController

Gate &Motor

Open Periodically

SluiceOperator

ManualController

Gate &Motor

Allow Operatorto Control Gate

c

a b

c

Combine

Combine

Translate

Import

PD3

Modify

PD1

PD2

PD3

Parallel iterations

Export

PD3

Translate

PD2

Combine

Combine

PD2

Modify

ExportImport

Closing the loop

PD1

PD2

PD3

Translate TranslateTranslate

PD1

PD2

PD3

Export

PD2

PD3

Modify ModifyCombine

ImportExportImport

Combine

Combine

The Role of VDM++ The following is specified using VDM++:

The syntax of hierarchical CPN The syntax of Problem Diagrams Algorithms:

Translate Generation of link/machine/domain/requirement modules Generation of color sets

Combine Structural validation of input models

Export XML generation Color set dependency

Future / Current Work

Automated checking of traces against real-time requirements expressed as high-level sequence diagrams (i.e. scenarios)

Integration with the Problem Oriented Engineering approach