The purpose of the EAST-ADL Methodology, developed in the ATESST2 project, is to give guidance on the use of the EAST-ADL language for the construction, validation and reuse of a well-connected set of development models for automotive embedded software.
Given the complexity of the development activities in automotive embedded software development, it is mandatory to structure the methodology so as to enable a relatively fast and easy access to the EAST-ADL language for a small kernel of essential development activities which can then be seamlessly extended to a comprehensive treatment of the language including more specialised development activities which may not necessarily be used in any development project. Hence the methodology is structured into two major components, as illustrated in Figure 1:

Figure 1 - The structure of the EAST-ADL methodology
The main component, the kernel methodology part, comprises a top-down description of the central constructive phases of automotive embedded software development.
The left side of the kernel methodology directly reflects the abstraction levels adopted by EAST-ADL. These phases describe the tasks and activities that need to be performed on the respective abstraction level in order to efficiently use the language in automotive embedded system development. The implementation phase, however, contains a reference to the AUTOSAR methodology. It therefore only describes how to transit from the design phase to implementation in AUTOSAR.
On the right side, integration and verification and validation is found. The focus in the EAST-ADL methodology is in these phases on the V&V aspects.
The kernel methodology is extended into a comprehensive methodology for automotive development projects by adding three additional and orthogonal activities to each of these phases:
· Specification of V&V cases to be executed and evaluated during the corresponding integration phase. V&V cases are most typically test cases, but can also include reviews etc.
· Verification of the model on a given abstraction level to the requirements of the model at the abstraction level directly above.
· V&V activities on the model artifacts of a given level itself, i.e. peer reviews, consistency checks, check of modelling guidelines etc.
The second main component of the EAST-ADL methodology consists of a set of complementary loosely-coupled extensions to the kernel methodology. Each of these extensions may be used as an add-on to the kernel activities. The following extensions are currently included:
· Environment Modeling: Modeling of the (typically analog or discrete-analog) environment of the system to be developed.
· Requirements and V&V: Detailed handling of complex requirements and V&V artiofacts.
· Safety Assurance: Development of Safety-critical systems
· Timing: Detailed handling of timing requirements and properties.
· Variability Modeling: Detailed handling of variability modeling.
· Behavior modeling: Detailed handling of behavioral modeling
The main idea is that the user of the methodology can compose any set of extensions with the kernel. In order to illustrate the intended correlation and interaction between the extensions, the EAST-ADL methodology presents four different configurations (where a configuration is a set of extensions plus the kernel) of increasing complexity:
· Core: Only basic structural models in the kernel methodology.
· Quality: Requirements and V&V extensions are added to Core.
· Quality+: Variability, timing, behavior and reuse added to Quality.
· Safety: Safety added to Quality+.
The timing extension
All timing aspects, including analysis, are captured in the timing extension. The timing extension contains a simplified and collapsed version of the TIMMO methodology, and has a clear focus on specification of timing constraints in the vehicle, analysis and design phases. The reason is that the analyses indicated in the vehicle and analysis phases of the TIMMO methodology are of relatively informal nature. Detailed timing analysis is not available until a hardware architecture is defined in the design phase. The implementation phase of the EAST-ADL methodology does not contain any timing since AUTOSAR v3.1, to which the methodology interfaces, does not support timing.
The timing extension of the EAST-ADL methodology contains the following tasks:
· Capture Vehicle Timing: End-to-end timing constraints as well as other timing contstraints relevant for Vehicle Features are defined.
· Capture Internal Analysis Timing: A budget of delay timing constraints making up end-to-end timing as well as other timing constraints constraining elements inside the FunctionalAnalysisArchitecture are defined.
· Capture External Analysis Timing: End-to-end timing constraints as well as other timing contstraints on external input and outputs are defined
· Assess Timing Feasibility: Consistensy of timing constraints and feasibility of meeting timing constraint under a chosen DesignArchitecture is assessed.
· Capture External Design Timing: End-to-end timing constraints as well as other timing contstraints on external input and outputs are defined.
· Capture Internal Design Timing: A budget of delay timing constraints making up end-to-end timing as well as other timing contstraints constraining elements inside the FunctionalDesignArchitecture are defined.
Relation to the TIMMO-2-USE methodology
The EAST-ADL methodology addresses all aspects of the automotive EE development process, whereas the TIMMO-2-USE methodology focuses on a certain set of use cases related to timing that are mapped to a Generic Methodology Pattern (GMP), see section 3. The GMP summarises all tasks in all extensions (except timing) of the EAST-ADL methodology in one task: Create solution. The tasks in the timing extension correspond to the other tasks in the GMP. However, such mapping is not straight-forward and will result in a many-to-many relation. |