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Introduction to Complex System Engineering. Emmanuel FUCHS Slides available soon at www.elfuchs.fr. Information Systems. Complex System Examples. System Problems Examples. System Problems Examples. System definition (Eberhardt Rechtin 1926-2006).
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Introduction to Complex System Engineering Emmanuel FUCHS Slides available soon at www.elfuchs.fr
Information Systems ComplexSystem 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 Mission System Users Sub System Border Sub System Sub System Stakeholders Environment
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
As designed by the project analyst As specified in the project request As proposed by the project sponsor As proposed by the programmers What the customer really want As installed at the users’ site Design the right system
Process Definition • Set of interrelated of interacting activities which transforms inputs to outputs P Inputs Outputs
Sequential V cycle drawbacks Documentation And mock-up Phase
Sequential V cycle drawbacks Documentation And mock-up Phase
Iterative and Incremental Iterative Incremental
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.
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
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
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
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
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