Complex System Engineering
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Introduction to Complex System Engineering Emmanuel FUCHS Slides available soon at www.elfuchs.fr
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Transcript of Complex System Engineering
Introduction to Complex System Engineering
Emmanuel FUCHS
Slides available soon at www.elfuchs.fr
Information Systems
ComplexSystem
Examples
System ProblemsExamples
System Problems Examples
System definition (Eberhardt Rechtin 1926-2006)
• A system is a construct or collection of different elements that together produce results not obtainable by the elements alone.
• The elements, or parts, can include people, hardware, software, facilities, policies, and documents; that is, all things required to produce systems-level results.
• The results include system level qualities, properties, characteristics, functions, behavior and performance.
• The value added by the system as a whole, beyond that contributed independently by the parts, is primarily created by the relationship among the parts; that is, how they are interconnected.
Systemic
The whole is greater than the sum of the parts;
The part is greater than a fraction of the whole.Aristotle
System: another definition
• A system is any set (group) of interdependent or temporally interacting parts.
• Parts are generally systems themselves and are composed of other parts, just as systems are generally parts of other systems.
System Definition
SubSystem
SubSystem
SubSystem
SystemUsers
Mission
EnvironmentStakeholders
Border
System Meta Model
From INCOSE
SE Bodies
• http://www.afis.fr/– Association Française d'Ingénierie Système
• http://www.incose.org/– International Council on Systems Engineering
(INCOSE)
System Engineering Definition
“an interdisciplinary approach encompassing the entire technical effort to evolve and verify an integrated and balanced set of system, people, product, and process solutions that satisfy customer needs…..”
System Engineering (SE)
• SE focuses on defining customer needs and required functionality early in the development cycle, documenting requirements, then proceeding with design synthesis and system validation while considering the complete problem
• Systems engineers deal with abstract systems, and rely on other engineering disciplines to design and deliver the tangible products that are the realization of those systems.
• Systems engineering effort spans the whole system lifecycle.
Systemic Approach
• One + One > two
• Aristotle : The whole is more than the sum of its parts.– Parts (Components)– Connections
System Engineering Meta Model
From INCOSE
System engineer/architect
• Works with system abstraction.– It is impossible to master everything
• Requirements Management• System Model
Design the right system
As proposed bythe project sponsor
As proposed by the programmers
As specified in the project request
As designed bythe project analyst
As installed at the users’ site
What the customer really want
Process Definition
• Set of interrelated of interacting activities which transforms inputs to outputs
P
Inputs Outputs
A Process
Process: V cycle
Sequential V cycle drawbacks
DocumentationAnd mock-up
Phase
Sequential V cycle drawbacks
DocumentationAnd mock-up
Phase
Iterative and Incremental
Incremental
Iterative
Barry W. Boehm
Iterative and Incremental
• The Systems Engineering Process is not sequential. It is parallel and iterative.
• The complex interrelationship between creating and improving models throughout the process of developing and selecting alternatives is a good example of the dynamic nature of the systems engineering process.
Process Standardization
• NASA• DOD (US Departement Of Defense):
– Documentation Model
• IEEE• ISO (International Organization for
Standardization) • IEC (International Electrotechnical Committee).
– ISO/IEC 15504 / SPICE (Software Process Improvement and Capability dEtermination)
• SEI (Software Engineering Institute)
Capability Maturity Model - Integration
• CMMI defines the essential elements of effective processes for engineering disciplines based on best industry experiences.
• CMMI models provide guidance when developing and evaluating processes.
• CMMI models are not actually processes or process descriptions.
CMMI Maturity Levels
Level Identified as Status
5 optimizing focus on process improvement
4quantitatively managed process measured and controlled
3 definedprocess characterized for the organization and is proactive
2 managedprocess characterized by projects and often reactive
1 initialprocess uncontrolled poorly managed and reactive
Process Documentation and Review
• SSS: System/Segment Specification • SSDD : System/Segment Design Document • IRS : Interface Requirement Specification• ICD : Interface Control Definition
• SRR : System Requirement Review• SDR : System Design Review• TRR : Test Readiness Review
Process Activities
What is a requirement ?
• A requirement is a condition to be satisfied in order to respond to:– A contract– A standard– A specification – Any other document and / or model imposed.
Requirements
• User’s Requirements– Statements in natural language of the system
services.– Described by the user
• System Requirements– Structured document setting out detailed
description of system services. – Part of the contract
User’s Requirements example
• A customer must be able to abort a transaction in progress by pressing the Cancel key instead of responding to a request from the machine.
• The washing machine will be used in the following countries: UK, USA, Europe, Eastern Europe
Process
System Requirements
• The System shall provide ........ • The System shall be capable of ........ • The System shall weigh ........ • The Subsystem #1 shall provide ........ • The Subsystem #2 shall interface with .....
Requirement Quality
• A good requirement states something that is necessary, verifiable, and attainable
• To be verifiable, the requirement must state something that can be verified by:– analysis, inspection, test, or demonstration
(AIDT)
Requirement analysis
• User Requirement– Minimum levels of noise and vibration
are desirable.
• System Requirement– Requirement 03320: The noise
generated shall not exceed 60 db
Requirement Types
• Functional requirements– Functional requirements capture the intended
behavior of the system. – This behavior may be expressed as services,
tasks or functions the system is required to perform
• Non-Functional requirements– All others
• Constraints
Process
System Architecture
• The System Architecture identifies all the products (including enabling products) that are necessary to support the system and, by implication, the processes necessary for development, production/construction, deployment, operations, support, disposal, training, and verification
Architecture Modeling
• System : Abstraction– Functional model– Dynamic model– Semantic Model– Object model– Physical Model– Interfaces Model
• Model Views
Architecture Meta Model
From IEEE
Architecture and Components Assembly
Example of Architecture Views
• The Functional Architecture – identifies and structures the allocated
functional and performance requirements.
• The Physical Architecture– depicts the system product by showing how it
is broken down into subsystems and components
Functional To Physical Model
• Functional : Discover the system functions
• Washing Machine– What it does ?
• Washes
– How it does ?• Agitates
– Physical Component : Agitator
Functional VS physical Model
• How to fly ?• Look at birds: Physical Model• So I need: Legs, Eyes, Brain, and Wings.• But I can not fly !!!• Why ?• I have to find the flight functional model !
Flying functional model
• Functional decomposition of flying function:– Produce horizontal thrust,– Produce vertical lift. – Takeoff and land, – Sense position and velocity, – Navigate,
Example Birds physical for flying
• Physical decomposition: – physical components that birds used to fly:
Legs, Eyes, Brain, and Wings.
• But can not be applied to system directly
Function Airplane Physical
Component Bird Physical
Component
Takeoff and land Wheels, Legs
Sense position and velocity
Vision or radar Eyes
Navigate Brain or computer Brain
Produce horizontal thrust
Propeller or jet Wings
Produce vertical lift Wings Wings
Bird and Airplane Functional to Physical architecture
mapping
Multi-criteria decision
Trade Off
• Multi-criteria decision-aiding techniques are available to help discover the preferred alternatives.
• This analysis should be repeated, as better data becomes available.
Washing Machine example
Context Diagram
Washing Machine Functional Breakdown
Washing Machine Data Flows
Washing Machine Physical Model
agitator
tube
draining
hand-operated washer
plungers
Washing Machine Physical Modelagitator
Outer tube
draining
top loading
US
Washing Machine Physical Model
agitator
Outer tube
draining
Inner tube = drum
front loading
Europe
Process
Integration
• Integration means bringing things together so they work as a whole.
Spaghetti Plate Syndrome
Spaghetti Plate Syndrome
Spaghetti Plate Syndrome
Spaghetti Plate Syndrome
Spaghetti Plate Syndrome
Spaghetti Plate Syndrome
Spaghetti Plate Syndrome
Spaghetti Plate
Spaghetti Plate Syndrome
Spaghetti Plate
System Architect
Spaghetti Plate Syndrome
Spaghetti Plate
System Architect System Integrator
Encapsulation Analogy
Implementation Interface
A driver doesn't care of engine's internal working.He only knows the interface
Process
IVVQCA
• Integrate : – Build the system
• Verification : – Ensures that you built it right
• Validation : – Ensures that you built the right thing
• Certification : – Ensure that the system is safe
• Acceptance : – Ensures that the customer gets what he wants and
the company get paid.
Ensure that the system is safe
Conclusion
Thank You For Your Attention
Questions are welcome
Contacts :
Slides Available soon at www.elfuchs.fr
