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GCRI · Engineering

Systems engineering

Systems engineering is an interdisciplinary approach to designing and managing complex systems over their life cycle. It focuses on requirements, interfaces and interactions so that the whole performs as intended. Systems Science and Modelling stewards this page for the Nexus Consortium.

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01Workspace

The workspace for systems engineering.

Network analysis

The Global Centre for Risk and Innovation (GCRI) · Systems engineering · Run R-0424 · Example interface, not a record

Single point of failureGCRI · GCRI

Dependency graph

nodes: assets · edges: dependencies

Most central nodes

N30.1911Critical
N40.276Normal
N50.413Normal
N60.229Normal

Cascade size under removal

Network analysis.Illustrative interface; not live data.

GCRI · Network analysis. Network analysis: example names and illustrative values, not a record.

02The method

What systems engineering covers.

  1. 01

    Core methods

    requirements engineering; functional decomposition; interface management; model-based systems engineering; trade-off analysis; verification and validation planning.

  2. 02

    Data and instruments

    requirements databases; system architecture models; test records; configuration management records; operational performance data.

  3. 03

    Validation

    Each requirement is traced to verification evidence from analysis, inspection, demonstration or test. Independent reviews check completeness at life cycle gates.

  4. 04

    Limits

    Emergent behaviour in open or socio-technical systems may not be captured by requirements. Rigid processes can slow adaptation to change.

  5. 05

    Use in risk decisions

    Systems engineering exposes interfaces where failures propagate between components and organisations. It supports designing interconnected infrastructure with explicit dependency management.

03Reference practice

Systems engineering is codified in life-cycle standards.

ReferenceWhat it sets
ISO/IEC/IEEE 15288System life-cycle processes
INCOSE Systems Engineering HandbookPractice guidance
Model-based systems engineering (SysML)Formal system models
04Process

How the process runs.

Process

Systems engineering: Cascade across systems

An initial hazard can trigger later risks and events; this illustration draws one cascade across systems such as energy, water, ICT, health and transport.

  1. 01 Hazard

    1. 01Initiating hazardDataset · National DeskCascading risk is the risk that hazard events trigger later risks and events, through chains of interrelated hazards or impacts.

  2. 02 First-order systems

    1. 02Example system: energyModel · System operatorAn example of a system a hazard can hit first. What depends on it is set by a dependency survey.
    2. 03Example system: waterModel · System operatorA second example of a system a hazard can hit first. Its links to other systems are shown as examples only.

  3. 03 Second-order systems

    1. 04Example system: ICTModel · System operatorAn example of a system that may depend on others, for example on backup power. Survey data set the real dependencies.
    2. 05Example system: health servicesModel · System operatorAn example of a system that may depend on water, power and data. Survey data set the real dependencies.
    3. 06Example system: transportModel · System operatorAn example of a system that may depend on ICT, fuel and logistics. Survey data set the real dependencies.

  4. 04 Limiting the cascade

    1. 07Buffers and redundancyStep · National DeskBuffers, redundancy and restoration can limit how far an impact spreads. The OECD report moves from single assets to system resilience.
    2. 08Restoration prioritiesDecision · National DeskThe responsible party sets which services are restored first, under its own rules.

Outline of an external standard or method, from its public sources. It describes what the framework says, not a record of any run. It does not show that Nexus or any partner performs, certifies or approves a step. A gate is a step of the method, never a Nexus approval. The dependencies are examples. A dependency survey for the place sets them.

05In systemic risk work

Requirements, interfaces and emergent behaviour.

Systems engineering manages the interfaces where components meet, which is where systemic failures occur. Applied to risk, it means specifying what a system must do under stress, tracing requirements to tests, and examining emergent behaviour that no component specification captures.

  • Specify requirements for degraded operation.
  • Trace each requirement to verification evidence.
  • Use interface analysis to find hidden dependencies.
  • Applications on Systems Modelling and Foundry.
06Applied in

Platforms that apply this method.

07Stewardship

Who maintains this page.

Systems Science and Modelling stewards systems engineering: it keeps this description current and reviews how the method is applied across the platforms.

08Sources

Where this page’s references lead.

The bodies and documents this page is read against. Status and editions change; each link goes to the issuing body.

09Questions

Questions and answers.

Why does one institution host every method page?
GCRI hosts the STEM Commons so that each method has one canonical description. Platforms link to it rather than repeat it, which keeps definitions consistent.
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Write to the integrity concern form with the passage and the reason.
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