Cse3 March2009cwd35with Crane

Introduction to Complex System Engineering 3 march 2009 Emmanuel FUCHS Slides available soon at www.elfuchs.fr

Content • Complex System Example • System Definition • System Engineering • Design The Right System • Process • Requirements • Design and Architecture • Functional and Physical Allocation • Integration • IVVQCA

Complex System Examples Information Systems

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;

T he 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 Sub System Sub System Sub System System Users Mission Environment Stakeholders 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 by the project sponsor As proposed by the programmers As specified in the project request As designed by the 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 Documentation And 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 process uncontrolled poorly managed and reactive initial 1 process characterized by projects and often reactive managed 2 process characterized for the organization and is proactive defined 3 process measured and controlled quantitatively managed 4 focus on process improvement optimizing 5 Status Identified as Level

ITIL

ITIL : Information Technology Infrastructure Library

http:// www.itil-officialsite.com

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

DOORS

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 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 !

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

Flying functional model

Functional decomposition of flying function:

Produce horizontal thrust,

Produce vertical lift.

Takeoff and land,

Sense position and velocity,

Navigate,

Allocations

Represent general relationships that map one model element to another

Different types of allocation are:

Behavioral (i.e., function to component)

Structural (i.e., logical to physical)

Software to Hardware

….

Bird and Airplane Functional to Physical architecture mapping Wings Wings Produce vertical lift Wings Propeller or jet Produce horizontal thrust Brain Brain or computer Navigate Eyes Vision or radar Sense position and velocity Legs Wheels, Takeoff and land Bird Physical Component Airplane Physical Component Function

Stove Pipe architecture User Functional Organization Physical

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.

Tower Crane example

Tower Crane example x

French Tower Cranes

British Tower Cranes

Luffing jib tower crane

When the jib is moved, the hoist gear is controlled in such a way as to ensure that the hook travels horizontally.

The two types of basic jib design

Horizontal Jib

This jib takes the form of a simple structure extending from the tower, along which a trolley can travel, carrying the hoist rope and hook assembly to vary radii.

Luffing Jib

The luffing jib has no trolley, the variation of hook radii is achieved by altering the jib angle, the same as with a mobile crane.

Horizontal Jib

Luffing Jib

These cranes have been designed for work on particularly high buildings or in extremely restricted spaces.

These cranes can solve all the problems that may appear in building sites settled in crowded places, in the town centres or in some areas full of obstacles like prefabricated buildings or towers.

Washing Machine example

Functional To Physical Model