1. UC Berkeley: Chess Vanderbilt University: ISIS University of Memphis: MSI CHESS Review May 10, 2004 Berkeley, CA Model-Based Design Edited by Janos Sztipanovits, Presented by Gabor Karsai ISIS, Vanderbilt University

2. CHESS Review, May 10, 2004 2 Objectives Model-based design focuses on the formal representation, composition, and manipulation of models during the design process. Specific research areas: 1.Composition of Domain Specific Modeling Languages 2.Model Transformation 3.Model Synthesis

3. CHESS Review, May 10, 2004 3 Concrete Syntax C Abstract Syntax A Semantic Domain S Semantic Mapping Parsing Concepts Relations Well formed-ness rules Mathematical abstraction for specifying the meaning of models Notation for representing models L = MCMC MSMS 1. Composition of Domain Specific Modeling Languages

4. CHESS Review, May 10, 2004 4 Research Agenda Research Agenda: 1.Using the Meta-Object Facility (OMG) as the meta-metamodel 2.Specification of DSML semantics via meta- modeling 3.Foundation for composing DSML-s 4.New Semantic Domains 5.Extension of meta-programmable tools Baseline: −Modeling of Abstract Syntax using UML class diagrams and OCL as meta language; −Meta-programmable Graphical Model Editor (GME)

5. CHESS Review, May 10, 2004 5 Semantics via Meta-Modeling: Baseline Concrete Syntax Abstract Syntax Semantic Domain Semantics parses to Meta-modeling language with well-defined semantics Concrete Syntax Abstract Syntax Semantic Domain Semantics parses to Represented by Meta-model Semantics DSML Meta-model Structural Semantics DSML: StateFlow DOMAIN-MODEL META-MODEL Meta-Model of StateFlow using uml/OCL as meta modeling language.

6. CHESS Review, May 10, 2004 6 New Direction: Precise Meta-Modeling CS A M C MSMS DSML MOF A DSML GME M C,DSML GME A DSML GME C DSML TLA A MOFTLA S MOF TLA M S,MOF C SA MSMS MCMC MOF TLA + GME MOF GME MOF GME MOF  TLA A MOFTLA S MOF TLA M S,MOF C SA MSMS MCMC MOF TLA + Modeled by Mapped into Concrete syntax modeling Abstract syntax modeling with MOF Set-valued semantics for MOF Meta-model MOF/TLA+ Model (meta-meta model) GME Meta- Programmable Model Builder Ongoing Work: ( Poster: Compositional Metamodeling for DSMLs ) Changing from UML-CD/OCL to MOF in abstract syntax modeling Developing set-valued semantics for MOF using TLA+ as meta-language Developing MOF A DSML  TLA A DSML translator

7. CHESS Review, May 10, 2004 7 Semantics via Translation: Baseline Concrete Syntax Abstract Syntax Semantic Domain Semantics parses to Concrete Syntax Abstract Syntax Semantics parses to Semantic Domain translator DSML Semantics Modeling language with well-defined semantics Synchronous Dataflow (SDF) translator Behavioral Semantics A SF Hierarchical Signal Flow (HSF) Lee, Sangiovanni-Vincentelli

8. CHESS Review, May 10, 2004 8 M HMA,MA SC A M C M S MA CS A M C MSMS HMA MOF A HMAMOF A MA HMA DM TLA + TLA S MA MOF’ T HMA,MA MOF MOF’ MOF TLA + TLA A MA TLA M S,MA M S : A HMA  S MA M S = M S1 ○ M S2 ○ M S3 M S1 : MOF A HMA  MOF A MA M S2 : MOF A MA  TLA A MA M S3 : TLA A MA  TLA S MA MA DM Metapr. transformer New Direction: Translational Specification of DSML Semantics Ongoing Work: ( Poster: Compositional Metamodeling for DSMLs ) TLA+ specification of the semantics of selected models of computations (reference models) Specifying DSML semantics via specifying mapping between the abstract syntax of DSML and the reference models Developing modeling and translation tools

9. CHESS Review, May 10, 2004 9 New Semantic Domains: HyVisual – Hybrid System Modeling Tool Based on Ptolemy II HyVisual is a DSML designed for hybrid system modeling, specialized from Ptolemy II by combining its CT and FSM domains.

10. CHESS Review, May 10, 2004 10 Major Applications of Meta Modeling: Metropolis Meta Model (Formal Model) How are designs represented in Metropolis? Metropolis “meta-model”: a language + modeling mechanisms –represents all key ingredients: function, architecture, refinement, platforms –parser and API to browse designs, interact with tools

11. CHESS Review, May 10, 2004 11 Must describe objects at different levels of abstraction –Do not commit to the semantics of any particular model of computation Define a set of “building blocks” –specifications with many useful Models of Computations can be described using the building blocks –Processes, communication media and schedulers separate computation, communication and coordination P1 P2 M S P1.pZ.write( )  P2.pX.read( ) pX pZpXpZ M’ Computation CommunicationCoordination Metropolis Meta-Model

12. CHESS Review, May 10, 2004 12 Core Metropolis “Meta Model” Processes –Concurrent Computation, sequential execution within each process –Execution within a process can be suspended with the AWAIT statement Interfaces –The types of Ports, bundle function declarations Media –Model Communication by providing definitions of Interface Functions –Passive, cannot run in their own threads Netlists –STRUCTURE and CONCURRENCY Quantity Managers –Performance modeling Constraints –Specification & Synchronization Formal Semantics –Operational Semantics based on Action Automata

13. CHESS Review, May 10, 2004 13 2. Model Transformations Platform-Based Design of Embedded Systems Matlab Code-Gen. if (inactiveInterval != -1) { int thisInterval = (int)(System.currentTimeMillis() - lastAccessed) / 1000; if (thisInterval > inactiveInterval) { invalidate(); ServerSessionManager ssm = ServerSessionManager.getManager(); ssm.removeSession(this); } private long lastAccessedTime = creationTime; /** * Return the last time the client sent a request associated with this * session, as the number of milliseconds since midnight, January 1, 1970 * GMT. Actions that your application takes, such as getting or setting * a value associated with the session, do not affect the access time. */ public long getLastAccessedTime() { return (this.lastAccessedTime); } this.lastAccessedTime = time; /** * Update the accessed time information for this session. This method * should be called by the context when a request comes in for a particular * session, even if the application does not reference it. */ public void access() { this.lastAccessedTime = this.thisAccessedTime; this.thisAccessedTime = System.currentTimeMillis(); this.isNew=false; } lastAccessedTime = 0L; lastAccessedTime = ((Long) stream.readObject()).longValue(); maxInactiveInterval = ((Integer) stream.readObject()).intValue(); isNew = ((Boolean) stream.readObject()).booleanValue(); Matlab Code-Gen. Domain-Specific Modeling Languages Generator Model-Based Generator Technology - Modeling of generators - Generating generators - Provably correct generators - Embeddable generators Configuration Specification Analysis Tool Code P i-1 PiPi P i+1

14. CHESS Review, May 10, 2004 14 Research Agenda Research Agenda: 1.Meta Generators: Specification and generation of model transformations using graph rewriting technology 2.Embeddable generators 3.Generative extensions to modeling languages Baseline: −Meta-models of the Abstract Syntax of the source and target DSML-s; −Tools helping the procedural implementation of translators

15. CHESS Review, May 10, 2004 15 Model Transformation Using Meta-Models and Graph Rewriting Rewrite Engine Input Models Target Models Physical interface Input abstract syntax Output abstract syntax Input Interface Output Interface A PI UDM GRE Metamodel of Input Metamodel of Output Metamodel of Transformation Meta-level: Translatordesign Implementation:Execution Formal, explicit, and precise model of the transformations Karsai/Agrawal, ISIS

16. CHESS Review, May 10, 2004 16 Component Specialization Model of Computation semantics defines communication, flow of control Ptolemy II model scheduler Schedule: - fire Gaussian0 - fire Ramp1 - fire Sine2 - fire AddSubtract5 - fire SequenceScope10 parser method call if block method call block … for (int i = 0; i < plus.getWidth(); i++) { if (plus.hasToken(i)) { if (sum == null) { sum = plus.get(i); } else { sum = sum.add(plus.get(i)); } … Java actor definitions are parsed and then specialized for their context. target code abstract syntax tree Specialize for data types parameter values scheduling By token unboxing inlining partial evaluation dead code elimination specializer

17. CHESS Review, May 10, 2004 17 3. Model Synthesis Modeling Controller Synthesis System Analysis Code Synthesis Validation Verification Target Analysis Platform Platform Models Plant Model Integrated Model Design Feedback Valid Model Code/Model Test Vectors Valid Code/ Model Design Feedback Download Valid Model Challenge: Compose plant and controller models using library components with alternatives so as to satisfy design constraints Example design flow:

18. CHESS Review, May 10, 2004 18 Research Agenda Baseline: −Constraint-based design space exploration coupled to a dataflow language Research Agenda: 1.Pattern-based model synthesis 2.Models of Computations as design patterns 3.Design constraints and design patterns for multiple Models of Computations

19. CHESS Review, May 10, 2004 19 Pattern-based Model Synthesis Component Abstraction (T A ) Design Space Modeling (M D ) Design Space Encoding (T E ) Design Space Pruning Design Decoding Component Reconstruction Simulink Behavioral Models And Model Components Main Design Flow Design Space Modeler DESERT Model Synthesis Flow Using meta-modeling and model transformations we made the constraint based design space exploration tool suite composable with different design flows. Neema, Sztipanovits, Karsai at EMSOFT 2003

20. CHESS Review, May 10, 2004 20 Example: Use of Model Translation in the DESERT Tool Chain Component Abstraction (T A ) Simulink® Metamodel Abstracted Simulink Model Components Design Space Metamodel