Model-Driven Analysis Frameworks
for Embedded Systems
George Edwards
USC Center for Systems and Software Engineering
gedwards@usc.edu
Presentation Outline
• Embedded Systems
– 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
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
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
4
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
5
Challenge: Constructing Interpreters
1. 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
2. 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
Model Interpreter Implementation Tasks
1.
Find a computational theory that derives the relevant
properties
2.
Determine the syntax and semantics of the
analysis modeling constructs
3.
Discover the semantic relationships between
the constructs present in the architectural
models and those present in the analysis
models
4.
Determine the compatibility between the
assumptions and constraints of the architectural
models and the analysis models, and resolve
conflicts
5.
Implement a model interpreter that executes a
sequence of operations to transform an
architectural model into an analysis model
6.
Verify the correctness of the transformation
6
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 domainspecific analysis and platform-specific synthesis
– Enables a family of analytic techniques to be applied to an
architectural model
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
MIF Extensibility
• Language 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
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
Modeling in XTEAM
XDEVS Simulation Framework
• Implements a
mapping from
architectural
models to a
discrete event
simulation
(DEVS) model
Invoke the
Apply
Traverse
architect- the
Interpret
domainmodel
defined
each
object
specific
framework
semantics
based
on at
extension at
each and
type
each
extension
context
extension
point
point
XDEVS Framework Extensions
• Employs the Strategy pattern to implement domainspecific 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
XDEVS Applications
• Providing design rationale
• Weighing architectural
trade-offs
• Discovering emergent
behavior of component
assemblies
• Generating test cases and
validating component
implementations
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
For More Information
Visit the XTEAM website:
http://www-scf.usc.edu/~gedwards/xteam.html
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.