A 2007 study by the National Academy of Sciences provides strong motivation to explore the use of dependability cases as a means to address verification, and ultimately, certification, of highly complex systems. Kestrel Technology, LLC, is developing a prototype extensible workbench to develop, maintain, and analyze safety cases – a specialized form of dependability cases. The CertWare workbench contributes several core modules supporting safety case models, and extends these with a service-based APIs for plugging new capabilities into the workbench for processing these models.
In addition to typical features such as multi-user safety case model editing, change tracking, and templates, the CertWare workbench emphasizes support for analysis of safety case model structure and content. The APIs for external tool integration provide support for a variety of analyses of the safety case models. Model transformations enable syntactic and semantic analysis. Probabilistic reasoning provides support for uncertain evidence and computations of confidence levels. Logical reasoning provides support for answering queries on the model, determining the impact of negative evidence or inconsistent arguments, and incorporating unknown data. Historical reasoning and trend monitoring supports project management for case production, including assessing the cost and schedule impact of revised requirements or rework.
Source code is available at our GitHub repository.
When choosing a new copy of Eclipse to run CertWare, it is easiest to start with the Eclipse Modeling Tools download package. To install the CertWare feature into any Eclipse use one of the project's update sites:
http://raw.github.com/nasa/CertWare/master/net.certware.feature.updatesitefrom the remote GitHub repository.
net.certware.feature.updatesitefrom the local copy of the repository
http://certware-update.s3.amazonaws.comfrom an S3 copy for major releases.
For information regarding using update sites to install software in Eclipse, see Installing new features with the update manager.
An installation guide document is also available for a step-by-step procedure.
See the version history for a summary of changes in each update.
See the license for legal terms regarding this software. Note that the full CertWare workbench includes two licenses that the installer presents for acknowledgment: one for the NASA open source agreement, and a second for a UCLA software agreement. The UCLA agreement refers only to the Bayesian reasoning engine software that is provided for research and education non-commercial use. Users can choose not to install this feature.
Several narrated movies are available for familiarization with the tools (English):
- Creating a project
- Creating new files
- Creating new diagrams
- Validating models and managing problems
- Using examples to populate initial models
- Using EGit for version control.
See also the Eclipse documentation for using EGit.
- Software metrics models and calculations.
See also the safety case metrics document.
- Exporting argument content
- Performing MAP and MPE queries on Bayesian network models
- Using semi-formal proofs
Contributions to the project objectives and implementation have been made by several parties:
The CertWare logo and some workbench graphics were created by Richard Mays.
Initial funding for CertWare development was provided by NASA Langley Research Center Contract NNL10AA08C.
The CertWare software is provided by the U.S. Government under NASA's Open Government Initiative. Please read the CertWare NASA Open Source Agreement for NASA and third party license terms and conditions.
The Bayesian reasoning engine embedded in the CertWare Bayesian Reasoning Support feature is provided by UCLA under terms for research and educational non-commercial use. Please see the agreement above for details.