Scenario-Driven Dynamic Analysis of Distributed Architectures

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Scenario-Driven Dynamic Analysis of Distributed Architectures Powered By Docstoc
					Presented by: Thabet Kacem

               Spring 2010
 Contributions
 Introduction
 Proposed Approach
 Related Work
 Reconception of ADLs
 XTEAM Tool Chain
 Discussion
 Conclusion
 Future Work
 Address the shortcoming of ADLs
 Propose a new conception of ADL within MDE
 Approach combines extensible modeling language
  within a framework enabling implementation of
  customized dynamic analysis at architectural level
 Approach was implemented in XTEAM which helped
  to accommodate both new modeling features and new
  architectural styles
 Emergence of highly distributed, resource constrained
  and mobile computing environments
 Consequence: Complexity of software development
  increased difficulties to cope with network latency,
  security & unpredictable network topology
 Efforts went toward raising the level of abstraction for
  describing large scale software systems beyond OO
 ADL emerged to provide the architect with a higher
  level of architectural constructs
 ADL has many problems:
    Focus on structural elements
    Rely on rigid formalisms
 Many crucial aspects of a system cannot be expressed
 MDE emerged as an approach to distributed software
 systems combining DSMLs with model transformers,
 analyzers and generators
Proposed Approach
 The approach combines extensible modeling
  languages with a model interpreter framework for
  rapid implementation of dynamic analysis at arch level
 Analysis provides information about the behavior &
  cross-cutting properties that help an architect to
  compare architectural alternatives and weigh tradeoffs
   Provides ADL extension for mobile systems
   Implements a set of dynamic analysis on top of the
    model interpreter framework
Proposed Approach
 Two requirements to success:
    Extensibility of the language to accommodate new
     domain-specific concepts
    Flexibility of tools to allow rapid implementation of new
     architectural analysis techniques
Related work
 GME: tool implementing MDE paradigm that enables
 the creation of DSML and other related models
Related work
 MILAN: compromises DSML for embedded systems
  based on a dataflow representation & a set of models
  to generate executable specs for simulation engines
 Automates the synthesis of software implementation
  for system models
 It provides highly accurate simulations
 Drawback: suitable for signal processing systems but
  not efficient for large scale distributed architectures
Related work
 WML &CUTS: it’s a DSML that enables dynamic
  analysis of component-based architectures
 WML creates models that are transformed into XML-
  based inputs for CUTS
 Drawbacks:
   WML performs syntactic translation not semantic
   The analysis is implemented in the emulator engine not
    the model interpreter
   It does not capture component behavior
Related work
 xADL: can accommodate new domain specific
 concepts. It is defined by XML schemas.
   Core Schema: standard constructs to all ADLs
   Extension Schema: new modeling elements that are
    written by domain experts
 Drawback: xADL toolset is semantically agnostic then
 it cannot be extended to enforce semantic consistency
Related Work
 FSP: a modeling notation for capturing the behavior of
  software architectural constructs
 Allows construction of composite behavior
 Drawback: It lacks research concerning the execution
  in heterogeneous environment, deployment and
Reconception of ADLs
 Key shortcomings for arch. Based approaches to
 software modeling:
   Inflexible notation with a narrow vocabulary
   Supporting tools that enable only a limited set of
 Assumption: Shortcomings can be addressed by
 representing ADL via domain specific language DSML
 and performing arch. Analysis via model interpreter
Reconception of ADLs
 Avoid the creation of ADL from scratch and use ADL
  composition and enhancement
 These concepts are present in XTEAM
 Model Interpreter framework allows the architect to
  implement custom analysis techniques without
  knowing details of semantic mapping
 Use the ‘hook’ methods implemented by architect
  where objects are arch. constructs defined in ADL
Reconception of ADLs
 Two types of analysis techniques:
    Static: relies on the formalism underlying models to
     provide info about system properties or possible errors
        Problem: Difficulty that system implementation must match
         the model so that the analysis can be relevant
    Dynamic: explores the behavior of the model-based
     arch. representations at runtime by executing them
    It is more useful in comparing high level design
     possibilities early in the development cycle and don’t
     rely on the experience of the architect
XTEAM Tool Chain
 XTEAM ADL: compose a structural ADL (xADL) with
  a behavioral ADL (FSP)
 Creates execution architecture representation
 Adds language extension to capture system change in
  order to help Model Interpreter to implement
  architectural analysis
 Semantic mapping is done by the Model Interpreter
XTEAM Tool Chain
XTEAM Tool Chain
 Domain Specific ADL extension:
   Example: Energy consumption
XTEAM Tool Chain
 Mobile Application testbed used to illustrate the
 energy consumption:
XTEAM Tool Chain
 The energy consumption simulation generator allows
 to do some measurements that can be plotted in
 function of time
XTEAM Tool Chain
 Many factors affect energy consumption:
   Assignment of components to host or deployment
   Determining a dynamic redeployment strategy when
    consumption values differ from expected values
 Many other ADL extensions exist in XTEAM:
   End to end latency
   Memory utilization
   Component reliability
 Three cases where the approach is relevant
    Providing design rationale
    Weighing tradeoffs
    Understanding compositions of Off-the-shelf
 Are these three cases enough to judge that the
  approach is reliable ?
 Is implementing the approach in XTEAM sufficient to
  say the approach is correct ?
 The paper presented a software arch-based approach
  to modeling & analysis of distributed architecture that
  leverage the domain specific extensibility provided by
  model-driven engineering
 Approach addressed shortcomings of ADL
 Deployed & evaluated on XTEAM
 Considered as an improvement over traditional ADL
  and other MDE tools
Future Work
 Use XTEAM in the context of real world security
  application in embedded & mobile devices
 Integrate XTEAM with Desi and Prism-MW
 Determine the exact class of analysis technologies

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