Structuring Formalism: System Description (SDSF)

A Structuring Formalism provides a way to organize and gain insights from AD Elements for a system-of-interest Architecture Description Framework (System-of-Interest ADF). This Structuring Formalism uses a two step approach aligned to the early life cycle processes found in ISO 15288:2015. These steps are to create:

• A System Description that captures the basic structure, behaviour and properties of a system-of-interest to establish a common language and understanding within the team.

• A System-of-Interest ADF that provides stakeholders with specific viewpoints and views of the system-of-interest based upon a whole system understanding of the system-of-interest.

The System Description is created using a SysDesc ADF that allows the System Description to be considered as an AD Element in the scope of the SysDesc ADF. This allows correspondences to be identified that promote re-use of AD Elements across a wider set of system-of-interests.

The concept of a System Description is used as the basis for this Structuring Formalism: System Description (SDSF). This document contains a description of the System Description (SDSF) that is used to gain insights about the AD Elements (including other System Descriptions) to structure the System-of-Interest ADF. This Structuring Formalism contains the following:

• A conceptual model of the Structuring Formalism: System Description (SDSF)  used to organize and gain insight from the AD Elements for the System-of-Interest ADF.

• The various steps for creating and using System Descriptions when gaining insight and enhancing reuse of the AD Elements .

• The Structural Categories that allow sharing and reuse of AD Elements using correspondences.

• Various links to examples and results from using the two step approach.

• The types of benefits that can be achieved using the System Description as an AD Element.

PDF: Structuring Formalism: System Description (SDSF), Version 0.4, 07-February-2023

used to create System Descriptions and related System-of-Interest ADF:

Context: Fit within the early ISO 15288:2015 life cycle processes

This System Description (SDSF) is used within the context of the life cycle of a system-of-interest identified in ISO 15288:2015. The early technical processes of the life cycle provide an opportunity to engage stakeholders about their concerns and needs for the system-of-interest. Establishing a common language and vision require conversations and co-creation of information. This can be seen as a two step process:

• Shaping the system-of-interest using a System Description (6.4.1, 6.4.2, 6.4.3) Blue Rectangle

• Creating the system-of-interest  Architecture Description Framework based upon the system-of-interest System Description (6.4.4) Green Rectangle

The following picture shows the two areas where these conversations can occur:

Shaping the system-of-interest (Blue Rectangle)

The first three processes (6.4.1, 6.4.2, and 6.4.3) build an understanding of the system-of-interest through identifying stakeholders and their needs and concerns, identifying stakeholder and system requirements and understanding the language (Ontology) and structure, behavior and system properties (capabilities) of the system-of-interest. The system-of-interest row (third row from the top) co-creates an understanding of the whole system through the creation of a System Description. The system engineering role or the system architect role is generally working to build this understanding across the team. One of the outcomes from the process 6.4.3 System Requirements Definition is a System Description. This step is similar to the process "Architecture Conceptualization" in ISO 42020:2019. The System Description is created using the SysDesc ADF as an Architecture Description.

Also during this period, insights can be gained through the identification and reuse of other system descriptions. This reuse is captured through correspondences across the various AD Elements, including other System Descriptions.

Creating the system-of-interest  Architecture Description Framework (Green Rectangle)

The System-of-Interest ADF provides viewpoints and views that address the full set of stakeholders and their concerns based upon the system description created in 6.4.3. The System Description provides a strong foundation for the creation of the additional AD elements needed for the System-of-Interest ADF. This step is very similar to the "Architecture Elaboration" process in ISO 42020:2019.

The insights gained from the System Description through identification of correspondences provides a way of reusing AD Elements across other Architecture Description Frameworks, such as viewpoints, model kinds, ADLs, etc.

This System Description (SDSF) Document

The Structuring Formalism consists of three key parts:

• The conceptual model of the System Description (SDSF)

• The approach to creating a SoI ADF based on the System Description (SDSF)

• The System Classification Framework for identification and use of existing systems and system descriptions.

Each of these parts are described in this System Description (SDSF).