The SSP Traceability Specification consists of the following parts:
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The Simulation Task Meta Data (STMD) file format specification, specifying how to store, retrieve and handle simulation task meta data.
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The Simulation Resource Meta Data (SRMD) file format specification, specifying how to store, retrieve and handle simulation resource meta data.
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Common definitions used in those specifications that can be re-used in other traceability contexts.
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The SSP Traceability Packaging specification, specifying how to package STMD and SRMD data, as well as related resources into SSP.
The ability to trace simulation results back to the requirements, models, procedures, rationale, etc., that influenced those results is one of the requirements for credible simulations.
Recognizing that formats already exist for most of those artefacts, the glue particle approach defines formats that allow the user to tie the relevant information together by referencing existing artefacts: Rather than incorporating all information into one homogenous file format, the format acts as a glue between existing file formats.
Thus the glue particle approach focuses on traceability, as well as the exchange between partners, or in heterogeneous IT environments. The role of a single glue particle is to provide the necessary context and relationships tying the relevant information together in transit between two parties or systems. It acts as an interchange standard, not necessarily as a native format used inside one party or system.
It is used to exchange relevant configuration and version statuses between partners and IT environments. For this the relevant information chains are derived from process steps (e.g. for traceability) and made explicit (configuration of information). Version statuses are also made explicit for traceability.
A glue particle does not store any version histories of the carried information but stores only one snapshot valid for a specific date and time. When such information is passed around multiple times, new glue particles incorporating new information are created. They may, however, reference former glue particles they are based on to allow easy reintegration of the new information into the original system.
The glue particle approach can be applied to engineering tasks in general. The STMD file format is the specific variant for simulation tasks.
In the sense of tracking simulation processes that have actually been performed, all relevant information about the simulation process should be recorded in the form of metadata. If necessary, these metadata can be evaluated at a later time in order to be able to trace simulation processes of the past.
The metadata for a simulation task is organized in XML files called STMD files. The structure of STMD files is specified by an STMD XML Schema. The glue particle approach implies that IT tools and systems that contribute or use metadata can read and write STMD files depending on the situation. The STMD files are filled step by step with metadata by the IT tools and systems involved in the simulation process. The graphic in figure Step by step filling of STMD file in an heterogeneous environment shows this principle of filling the STMD files step by step.
It is important to understand that STMD files do not document the simulation process itself. The STMD data format is not a process documentation format. STMD files document metadata of process inputs, procedures, outputs, responsibilities etc. that are associated with the simulation process.
The Simulation Traceability Glue Particle files are based on a generic traceability documentation layout that determines which descriptive elements are required to document simulation related activities in a transparent and comprehensible way in order to enable quality, traceability an re-usability. This layout is basically independent of the actual engineering activities described.
The high level Simulation Traceability Glue Particle layout with its overall structure and descriptive elements will be introduced and explained in the following.
Beside some general and partly technical attributes, which are valid for the whole Simulation Traceability Glue Particle, the basic structure consists of seven phase elements, which correspond to the phases of the Credible Simulation Process and an element General information in which information is summarized, which is also valid for the whole Simulation Traceability Glue Particle. The seven phases are
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AnalysisPhase
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RequirementsPhase
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DesignPhase
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ImplementationPhase
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ExecutionPhase
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EvaluationPhase
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FullfillmentPhase
All phase elements are subdivided into step elements, which have different names in each phase, corresponding to the steps of the Credible Simulation Process. Step elements are all structured identically, regardless of the semantic content of a step element: Each step element has the sub-nodes Input, Procedure, Output, Rationale, Links, LifecycleInformation, and additional sub-elements for Classification and Annotations.
In addition, the entire Simulation Traceability Glue Particle can be classified and annotated.
Glue Particles, by their nature, are not self-contained but reference many resources that they tie together in their function as glue particles. Packaging of glue particles together with their referenced resources into easily exchangeable packages is therefore of fundamental importance.
The current approach to packaging is based on the SSP 1.0 standard, which also serves as a base in other regards. Chapter xxx details how the currently defined particles can be packaged into SSP archives either stand-alone or in ways that allow the treatment of those archives as native SSP packages by SSP-aware processors. Additionally, ways of packaging glue particles into other container formats like FMUs are specified.
Glue particles tie the referenced resources together in a two-fold manner: The broad flow of dependencies from inputs via procedures to outputs, supported by rationale information is given by the explicit structure of the step elements.
This broad dependency chain can be enhanced via more fine granular links through the XML Links (XLinks) based link sections that are present in each step and phase.