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INCOSE UK ChapterAutumn Assembly 2001
Systems Engineering :Past, Present & Future
Professor Philip John, Cranfield [email protected]
Technical Requirement Specifications• System TRS• Subsystem TRSs
Interface Control Documents
Design Reviews
Multidisciplinary teams
System Proving
System Design methodologiesand supporting tools
Configuration Management
What is SE ?
Concurrent Engineering
Availability Reliability & MaintainabilityHuman Factors Logistics Support Analysis
Safety
Performance
Requirements Management Requirements Engineering
System Integration
Simulation & ModellingTrials
Standards
Functional ArchitecturePhysical Architecture
System Test, Evaluation & Acceptance
Verification & ValidationSystem Installation
Training
A Basic View of SE Process
User Requirements
System Design
Subsystem Testing
Integration Tests
Acceptance Tests
System Requirements
Sub-system Reqts
Sub-system Development & Build
System Tests
A Basic View of SE Process
User Requirements
System Design
Subsystem Testing
Integration Tests
Acceptance Tests
System Requirements
Sub-system Reqts
Sub-system Development & Build
System TestsUnderstanding the problem
Formulating anacceptable solution
Implementing the solution
Proving the solution
Process Improvements
Process Improvements
* Systematic, disciplined systems process
Process Improvements
* Systematic, disciplined systems process* Objective : balancing performance, cost & time
Process Improvements
* Systematic, disciplined systems process* Objective : balancing performance, cost & time* Need to avoid expensive, late surprises … early decisions
crucial
Process Improvements
* Systematic, disciplined systems process* Objective : balancing performance, cost & time* Need to avoid expensive, late surprises … early decisions
crucial* Focus on …
> identifying decision drivers & evaluating options> increased rigour through formal methods, scenarios, use cases etc> through life approach … making trade-offs> use of simulation, prototyping etc> multidisciplinary teams> information sharing, justification, traceability
Process Improvements
* Systematic, disciplined systems process* Objective : balancing performance, cost & time* Need to avoid expensive, late surprises … early decisions
crucial* Focus on …
> identifying decision drivers & evaluating options> increased rigour through formal methods, scenarios, use cases etc> through life approach … making trade-offs> use of simulation, prototyping etc> multidisciplinary teams> information sharing, justification, traceability
* Not much focus on the nature of systems themselves
Are process improvements enough ?
User Requirements
System Design
Subsystem Testing
Integration Tests
Acceptance Tests
System Requirements
Sub-system Reqts
Sub-system Development & Build
System TestsUnderstanding the problem
Formulating anacceptable solution
Implementing the solution
Proving the solution?
??
Understanding the problem
Automobile technology about 1890
Early Systems developmentsdrew heavily on previous experience
Automobile technology about 1890
Early Systems developmentsdrew heavily on previous experience
• Expectations centred on performance• Fundamental architecture based on years of evolution• Fundamental interactions and influences in the environment well precedented e.g. ‘we know who the stakeholders are’• … the problem to be tackled was clear
SE formalised in US defence & aerospace (e.g. B47 Stratojet)
Formalised Systems Engineeringdealt with similarly clear problems
… problem was fairly clear … aircraft & their operations were well understood … users & stakeholders were ‘obvious’
The Systems challengeis becoming more complex
The Systems challengeis becoming more complex
* Customer / Enterprise expectations> Constraints (performance, time, cost .. including through life cost etc)> Customers want Benefits achieved, not features for their own sake> We need to decide what is relevant to achieve those benefits> Customers want customisation & adaptability
The Systems challengeis becoming more complex
* Customer / Enterprise expectations> Constraints (performance, time, cost .. including through life cost etc)> Customers want Benefits achieved, not features for their own sake> We need to decide what is relevant to achieve those benefits> Customers want customisation & adaptability
* Enterprise environment> extended, global … organisations, team dynamics & decisions are complex
The Systems challengeis becoming more complex
* Customer / Enterprise expectations> Constraints (performance, time, cost .. including through life cost etc)> Customers want Benefits achieved, not features for their own sake> We need to decide what is relevant to achieve those benefits> Customers want customisation & adaptability
* Enterprise environment> extended, global … organisations, team dynamics & decisions are complex
* Highly integrated with environment & other systems> stronger, wider influences & interrelationships
The Systems challengeis becoming more complex
* Customer / Enterprise expectations> Constraints (performance, time, cost .. including through life cost etc)> Customers want Benefits achieved, not features for their own sake> We need to decide what is relevant to achieve those benefits> Customers want customisation & adaptability
* Enterprise environment> extended, global … organisations, team dynamics & decisions are complex
* Highly integrated with environment & other systems> stronger, wider influences & interrelationships
* Increasing rate of change … & uncertainty> need to establish through life robustness … through life influences
The Systems challengeis becoming more complex
* Customer / Enterprise expectations> Constraints (performance, time, cost .. including through life cost etc)> Customers want Benefits achieved, not features for their own sake> We need to decide what is relevant to achieve those benefits> Customers want customisation & adaptability
* Enterprise environment> extended, global … organisations, team dynamics & decisions are complex
* Highly integrated with environment & other systems> stronger, wider influences & interrelationships
* Increasing rate of change … & uncertainty> need to establish through life robustness … through life influences
* Situations are becoming increasingly varied & unprecedented
The Systems challengeis becoming more complex
* Customer / Enterprise expectations> Constraints (performance, time, cost .. including through life cost etc)> Customers want Benefits achieved, not features for their own sake> We need to decide what is relevant to achieve those benefits> Customers want customisation & adaptability
* Enterprise environment> extended, global … organisations, team dynamics & decisions are complex
* Highly integrated with environment & other systems> stronger, wider influences & interrelationships
* Increasing rate of change … & uncertainty> need to establish through life robustness … through life influences
* Situations are becoming increasingly varied & unprecedented….. We, as systems engineers, must decide what is relevant and
critical and highest priority more explicitly than ever before
The Systems challengeis becoming more complex
* Customer / Enterprise expectations> Constraints (performance, time, cost .. including through life cost etc)> Customers want Benefits achieved, not features for their own sake> We need to decide what is relevant to achieve those benefits> Customers want customisation & adaptability
* Enterprise environment> extended, global … organisations, team dynamics & decisions are complex
* Highly integrated with environment & other systems> stronger, wider influences & interrelationships
* Increasing rate of change … & uncertainty> need to establish through life robustness … through life influences
* Situations are becoming increasingly varied & unprecedented….. We, as systems engineers, must decide what is relevant and
critical and highest priority more explicitly than ever before…. we face open problems rather than closed problems
EmergentCapability
Influences (time, cost etc)
Related Systems
Wider environment /situation
Influences & Interactions
System
Implications for Systems Engineering
Implications for Systems Engineering
*We must establish a clear, common understanding of our view of the problem across stakeholders, the SE team etc
Implications for Systems Engineering
*We must establish a clear, common understanding of our view of the problem across stakeholders, the SE team etc*We cannot rely on previous precedents
Implications for Systems Engineering
*We must establish a clear, common understanding of our view of the problem across stakeholders, the SE team etc*We cannot rely on previous precedents* … this system context and associated decisions must be established and communicated explicitly
Implications for Systems Engineering
*We must establish a clear, common understanding of our view of the problem across stakeholders, the SE team etc*We cannot rely on previous precedents* … this system context and associated decisions must be established and communicated explicitly*Soft methods are essential in progressing such ‘open’ problems towards a tangible systems engineering programme
Formulating an acceptable solution
Systems solutions arebecoming more complex
Systems solutions arebecoming more complex
* An increasing number of subsystem options (choices) are available to us
Systems solutions arebecoming more complex
* An increasing number of subsystem options (choices) are available to us
* Systems are more highly integrated than ever> enabled by IT and communications technologies> moving away from the historical role of the human operator as the primary
system integrator and embedding more decisions in the system design
Systems solutions arebecoming more complex
* An increasing number of subsystem options (choices) are available to us
* Systems are more highly integrated than ever> enabled by IT and communications technologies> moving away from the historical role of the human operator as the primary
system integrator and embedding more decisions in the system design
* We are no longer constrained by historical system architectures> we need to develop more sophisticated architectural design approaches> many system architectures are unprecedented
Systems solutions arebecoming more complex
* An increasing number of subsystem options (choices) are available to us
* Systems are more highly integrated than ever> enabled by IT and communications technologies> moving away from the historical role of the human operator as the primary
system integrator and embedding more decisions in the system design
* We are no longer constrained by historical system architectures> we need to develop more sophisticated architectural design approaches> many system architectures are unprecedented
* The relationship between Function & Form is changing significantly
System Architecture
System Architecture
SYSTEM
Function
Subsystem
Function
Subsystem
Function
Subsystem
System Architecture
SYSTEM
Function
Subsystem
Function
Subsystem
Function
Subsystem
….‘DETAIL Complexity’Senge (1990)
System Architecture
SYSTEM
Function
Subsystem
Function
Subsystem
Function
Subsystem
….‘DETAIL Complexity’Senge (1990)
….‘DYNAMIC Complexity’
SYSTEM
Function
Subsystem
Function
Subsystem
Function
Subsystem
System Architecture
SYSTEM
Function
Subsystem
Function
Subsystem
Function
Subsystem
….‘DETAIL Complexity’Senge (1990)
….‘DYNAMIC Complexity’
SYSTEM
Function
Subsystem
Function
Subsystem
Function
Subsystem
This change in system characteristics has far
reaching implications for SE
Implications for Systems Engineering
Implications for Systems Engineering
* System Architectures must be designed with little or no precedent
> we must be more explicit and careful in our architectural designfrom the outset> we need to understand system interactions more explicitly … they are no longer ‘obvious’ … they must be explored and communicated
Implications for Systems Engineering
* System Architectures must be designed with little or no precedent
> we must be more explicit and careful in our architectural designfrom the outset> we need to understand system interactions more explicitly … they are no longer ‘obvious’ … they must be explored and communicated
* Organisational and contractual barriers are increasingly likely to cut through critical system relationships
Implications for Systems Engineering
* System Architectures must be designed with little or no precedent
> we must be more explicit and careful in our architectural designfrom the outset> we need to understand system interactions more explicitly … they are no longer ‘obvious’ … they must be explored and communicated
* Organisational and contractual barriers are increasingly likely to cut through critical system relationships* System evaluation …gaining confidence in our system ... is increasingly difficult
Proving the solution
Implications of increasing complexity
Implications of increasing complexity* The increased complexity of the external systems challenge :
> how do we assess the validity of our analysis of the important influences and interactions when they are unprecedented ? … how do we judge criticality ? … how do we judge if we’ve thought of everything ? … more difficult to identify all the stakeholders
Implications of increasing complexity* The increased complexity of the external systems challenge :
> how do we assess the validity of our analysis of the important influences and interactions when they are unprecedented ? … how do we judge criticality ? … how do we judge if we’ve thought of everything ? … more difficult to identify all the stakeholders
* The move from Detail Complexity to Dynamic Complexity in System design :> system interdependencies more difficult to identify … most are indirect …
again, many are unprecedented> system behaviour more difficult to predict with confidence … how do we
judge if we’ve done enough testing / simulation / scenarios / use cases ?> Historical techniques such as Failure Mode & Effects Analysis need to be re-
thought
Implications of increasing complexity* The increased complexity of the external systems challenge :
> how do we assess the validity of our analysis of the important influences and interactions when they are unprecedented ? … how do we judge criticality ? … how do we judge if we’ve thought of everything ? … more difficult to identify all the stakeholders
* The move from Detail Complexity to Dynamic Complexity in System design :> system interdependencies more difficult to identify … most are indirect …
again, many are unprecedented> system behaviour more difficult to predict with confidence … how do we
judge if we’ve done enough testing / simulation / scenarios / use cases ?> Historical techniques such as Failure Mode & Effects Analysis need to be re-
thought
* “Given system complexity, multiple & unexpected interactions of failures are inevitable” Normal Accidents, Perrow
Summary
Summary
* We face increased integration (internal and external to our system) and this has profound implications for Systems Engineering
Summary
* We face increased integration (internal and external to our system) and this has profound implications for Systems Engineering* These cannot be addressed by process improvements alone … it is crucial that systems engineers understand systems & their implications
Summary
* We face increased integration (internal and external to our system) and this has profound implications for Systems Engineering* These cannot be addressed by process improvements alone … it is crucial that systems engineers understand systems & their implications* “Soft” and “Hard” approaches must both be a fundamental part of the systems engineer’s skills
Summary
* We face increased integration (internal and external to our system) and this has profound implications for Systems Engineering* These cannot be addressed by process improvements alone … it is crucial that systems engineers understand systems & their implications* “Soft” and “Hard” approaches must both be a fundamental part of the systems engineer’s skills* Fundamental historical practices must be reassessed & progressed with increasing care and with explicit decisions and communication :
> e.g. problem closure, architecture design, FMECA, system evaluation
Systems Engineeringin the 21st Century
Understanding &Dealing withSYSTEMS
Process Discipline
Hard & Soft approaches,methods & tools
• Systems Engineering Body of Knowledge
• SE competencies
• Training & Education
• Continuing Professional Development