Chapter 1: Introduction to Systems Engineering April 2012

Aims of this Lecture To explain what we mean by “Systems Engineering” To discuss the different types of systems which may be encountered To identify which technologies may be applied

Booklist The textbook for this course is Benjamin S. Blanchard and Wolter J. Fabrycky (2011). Systems Engineering and Analysis (5 th Edition). Upper Saddle River, NJ: Prentice-Hall. ISBN 13:

What is a system? Functionally related elements which collectively form an identifiable whole (the “system”) The system must itself perform some sort of a function The elements may be physical or conceptual

Some terminology Components – the elements of which the system is composed Attributes – properties of individual components or of the system as a whole Relationships between (pairs of) components – so that the components interact to support the system’s functionality (common purpose) State – the values of the attributes and relationships at a particular moment in time

Types of components Structural –Static Operating –Dynamic components which “do the work” Flow –Things which change, such as information or energy

Attributes of components Color, strength, size, weight, power Network topology Maximum speed Machine on/off Volume of fuel

Relationships First order –Functionally necessary to both Second order –“synergistic”, the relationship is complementary Redundant –Duplicate components

Subsystem If system “A” is a component of (larger) system “B”, then “A is a subsystem of B”

Environment Anything outside the system Input to the system from the environment Output from the system to the environment Throughput is –Input, processed by system, then output

Types of systems Natural vs. human-made –Also human-modified Physical vs. conceptual –Also systems of systems Static vs. dynamic –Uncertainty in dynamic systems Closed vs. open –Entropy

Systems Science Science vs. philosophy The Scientific Method Feedback (cybernetics) Homeostasis (biology) “Hierarchy of levels” (Boulding) Systemology – the science of systems –Cybernetics, OR, management science, IS, etc.

Technical systems Technology embedded in society Manufactured components of a system Classification difficult  Continuous change

History and philosophy Industrial age (1700 onwards) –Reductionism and mechanism –Mechanization –Analytic thinking Post-industrial (systems) age (1950 onwards) –Expansionism –Synthetic thinking –Teleology –Societal organizations

Engineering Civil, mechanical, electrical, electronic, … Communication Subcontracting Multidisciplinarity → “Systems engineering”

Systems engineering Various definitions exist Common themes –Top-down approach –Life-cycle –Requirements definition –interdisciplinarity

Factors to Consider when Constructing a Model Assumptions Simplifications Limitations Constraints Preferences Optimization of some of these factors may be mutually exclusive