1. Model-Driven Analysis Frameworks for Embedded Systems
George Edwards
USC Center for Systems and Software Engineering

2. Presentation Outline Embedded Systems Model-Driven Engineering
Modeling
Analysis
Model-Driven Engineering
Domain-specific languages
Model interpreters
Challenge: Performing Analysis on Domain-Specific Models
Promising Solution: Model Interpreter Frameworks
XTEAM
Modeling environment
Discrete event simulation framework
Conclusions

3. Modeling Embedded Systems
Diversity and heterogeneity
Different operating platforms
Wide varieties of scale
Result: no “one-size-fits-all” modeling language
Close and continual interaction with the physical environment and electrical, mechanical, and biological systems
Result: models need to incorporate elements of these systems
Strict operating requirements
Result: models need to be analyzable, executable

4. Analysis of Embedded Systems
Quality attributes are system properties that describe how services are performed
Also called non-functional or quality-of-service properties
Evaluation of quality attributes is critical in meeting overall end-user operational goals
Modification of a system that does not meet quality attribute requirements is difficult and expensive
Overall goal: Quantitatively and objectively evaluate quality attributes during system design to arrive at a better overall system

5. Model-Driven Engineering
Model-driven engineering (MDE) combines domain-specific modeling languages with model analyzers, transformers, and generators
Metamodels define elements, relationships, views, and constraints
Model interpreters leverage domain-specific models for analysis, generation, and transformation

6. Challenge: Constructing Interpreters
Model Interpreter Implementation Tasks
Find a computational theory that derives the relevant properties
Determine the syntax and semantics of the analysis modeling constructs
Discover the semantic relationships between the constructs present in the architectural models and those present in the analysis models
Determine the compatibility between the assumptions and constraints of the architectural models and the analysis models, and resolve conflicts
Implement a model interpreter that executes a sequence of operations to transform an architectural model into an analysis model
Verify the correctness of the transformation
Using the standard MDE process, a model interpreter must be constructed for each analysis that will be applied to a model
Significant investment of effort
Constructing and maintaining DSMLs and interpreters is difficult and expensive
Little guidance exists on how to construct DSMLs and interpreters
Requires particular type of expertise
Common topic of research papers in the modeling community

7. Solution: Model Interpreter Frameworks
Use a model interpreter framework to implement domain-specific analysis
An infrastructure for automated construction of analysis models from domain-specific architectures
Leverages the commonality among domain-specific architectural modeling languages
Provides extension mechanisms to accommodate domain-specific analysis and platform-specific synthesis
Enables a family of analytic techniques to be applied to an architectural model

8. Role of MIFs
Abstracts the details of domain-independent interpretation
Allows engineers to implement domain-specific interpretation
Produces an artifact useful in a wide variety of contexts

9. MIF Extensibility Language Extensions Module Extensions
Permit the definition of new domain-specific constructs
Design approach: define a new class that implements the semantics of each new type
Example: middleware component models, reference architecture types
Module Extensions
Permit the replacement of core simulation algorithms and functions
Design approach: modularize each algorithm and abstract algorithms behind standard interfaces
Examples: Real-time scheduling, publish-subscribe services
Plug-in Extensions
Permits implementation of domain-specific analysis techniques
Design approach: create hooks where call-backs occur
Examples: resource utilization monitor, stochastic workload generator

10. The eXtensible Toolchain for Evaluation of Architectural Models
A modeling environment and accompanying set of model interpreter frameworks for software architectures
Consists of:
A specialized metamodeling language
A suite of model interpreter frameworks
Example extensions targeted towards resource-constrained and mobile computing environments
Provides the extensibility to easily accommodate both new modeling language features and new architectural analyses

11. Modeling in XTEAM

12. XDEVS Simulation Framework
Invoke the architect-defined framework extension at each extension point
Apply domain-specific semantics at each extension point
Traverse the model
Interpret each object based on type and context
Implements a mapping from architectural models to a discrete event simulation (DEVS) model

13. XDEVS Framework Extensions
Employs the Strategy pattern to implement domain-specific extensions
Each Concrete Strategy generates code to realize a particular analysis
Invoked at specific times during the interpretation process
Generated code calculates and records analysis results

14. XDEVS Applications Providing design rationale
Weighing architectural trade-offs
Discovering emergent behavior of component assemblies
Generating test cases and validating component implementations

15. Conclusions
Lack of automated mechanisms for applying model transformations to and performing analysis on domain-specific models
Our methodology leverages extensible frameworks to simply the analysis of embedded systems

16. Visit the XTEAM website:
For More Information
Visit the XTEAM website:
XTEAM Publications:
George Edwards and Nenad Medvidovic, A Methodology and Framework for Creating Domain-Specific Development Infrastructures, Proceedings of the 23rd IEEE ACM International Conference on Automated Software Engineering (ASE), September 2008.
George Edwards, Chiyoung Seo, and Nenad Medvidovic, Model Interpreter Frameworks: A Foundation for the Analysis of Domain-Specific Software Architectures, Journal of Universal Computer Science (JUCS), Special Issue on Software Components, Architectures and Reuse, 2008.
George Edwards, Chiyoung Seo, and Nenad Medvidovic, Construction of Analytic Frameworks for Component-Based Architectures, Proceedings of the Brazilian Symposium on Software Components, Architectures and Reuse (SBCARS), August 2007.
George Edwards, Sam Malek, and Nenad Medvidovic, Scenario-Driven Dynamic Analysis of Distributed Architectures, Proceedings of the 10th International Conference on Fundamental Approaches to Software Engineering (FASE), March 2007.