SYSTEMS ENGINEERING FUNDAMENTALS 4/10/2003 1

Transcription

1 SYSTEMS ENGINEERING FUNDAMENTALS 1

2 WHAT S A SYSTEM? DOD : An integrated composite of people, products, and processes that provide a capability to satisfy a stated need or objective. NASA: A set of interrelated components which interact with one another in an organized fashion toward a common purpose. INCOSE: A construct or collection of different elements that together produce results not obtainable by the elements alone. 2

3 SOME EXAMPLES OF SYSTEMS NEW COMPUTER NETWORK SYSTEM REUSABLE LAUNCH SYSTEM A UNIVERSITY NATIONAL MISSILE DEFENSE SYSTEM 35 MM CAMERA SYSTEM TRANSPORTATION SYSTEM COMMUNICATION NETWORK SYSTEM A ROCK? THE EARTH? A CAR? 3

4 ROCK SYSTEM? Crystalline structure formed of various chemical compounds Chemical compound is formed from chemical elements Each Element is composed of protons, neutrons, and electrons Even though a rock has a well defined boundary, a rock can be a part of a river bed or part of a geological formation 4

5 SOMEONE S SYSTEM IS SOME ELSE S SUBSYSTEM A system is most often hierarchical. Your system is someone else s subsystem Someone s system, may be your subsystem. 5

6 System Understanding Environment Boundary Environment Boundary System Environment Boundary System Description Objective or Function: What is purpose or goal? Is it static or dynamic? Is it open or closed? Control: How is it regulated? Structure: How is it assembled? Is it physical or conceptual? Complexity: How many parts and how are they related? Origin: Is it natural, man-made, etc.? System Elements Components Attributes Relationships 6

7 SYSTEMS ENGINEERING DEFINITIONS International Council Of Systems Engineers (INCOSE): An interdisciplinary approach and means to enable the realization of successful systems. Electronic Industry Alliance (EIA) Standard IS-632, Systems Engineering (1994): An interdisciplinary approach that encompasses the entire technical effort, and evolves into and verifies an integrated and life cycle balanced set of system people, products, and process solutions that satisfy customer needs. Institute of Electrical and Electronics Engineering (IEEE) 1220, Standard for Application and Management of the Systems Engineering Process (1994): An interdisciplinary, collaborative approach that derives, evolves, and verifies a life-cycle balanced system solution which satisfies customer expectations, and meets public acceptability. 7

8 WHY SYSTEMS ENGINEERING? Increased complexity of products and processes Large number of interfaces among components, sub- components, etc Evolution of world wide competitive markets & Time to Market (Competition) Exponential expansion of knowledge & technology Customer demand for optimized systems Individuals can no longer solve complex problems by themselves. It has become necessary to organize multi-disciplined teams where each member contributes a specific skill or expertise to achieve a common goal. 8

9 SYSTEM COMPLEXITY EXAMPLE INDY RACE CAR Carbon- Fiber Skin Sophisticated electronic nervous system Serpentine wires Precision sensors LCDs Spread spectrum wireless communications equipment Antilock brake systems kick in when sensors detect a spin Data Acquisition Geeks (DAGs) Laptop pulse monitoring of a 800 horsepower data terminal remote control as it speeds around the track at 220mph 9

10 RAPID TECHNOLOGY CHANGES Miles per Hour Speed of Human Transportation Speed of a galloping horse: 43 MPH Fastest Jet Airplane: 2193 MPH Speed of sound 758 MPH ; Chuck Yeager October Time (AD) Nuclear powered space craft: 32,000 MPH Fastest rocket powered airplane: 4534 MPH Bullet Trains: 300 MPH Steam powered trains: 126 MPH First Autos: 39 MPH Fastest jet-powered automobile: 740 MPH Fastest Prop Plane: 600 MPH Stafford Beer: Brain of the Firm 10

11 THREE BASIC ARGUMENTS FOR THE VALUE OF SYSTEMS ENGINEERING Assurance that the system will accomplish its objectives The cost-time trade effect Cost to fix a missed requirement Time from project start Insurance against serious low-probability consequences 11

12 COST OVERRUN AS A FUNCTION OF SYSTEMS ENG. EFFORT 200 * GRO 78 Cost Overrun (%) * OMV * TDRSS GALL * * HST * TETH CEN * * MARS * CHA * STS SEASAT * * UARS * DB * COBE * ERB 80 * Voyager * Ulysses * ISEE * HEAO Systems Engineering Effort (% of Total Cost) Reference: Metrics and Case Studies for Evaluating Engineering Designs, Moody et al 12

13 AEROSPACE SYSTEMS FAILURES - EXAMPLE OF THE NEED FOR SYSTEMS ENGINEERING Multiple failures across different launch vehicles and contractors Vehicle Launch Spacecraft Failure Mode Titan IVA Aug 98 NRO Electrical cable short Delta III 26 Aug 98 Galaxy 10 Vehicle roll stability Titan IVB-27/IUS-21 9 Apr 99 DSP-19 IUS Stage separation Athena II 27 Apr 99 IKONOS Fairing failure to sep Titan IVB-32/Centaur Apr 99 MILSTAR-3 Centaur guidance s/w Delta III 4 May 99 ORION-III RL10-B2 engine No common hardware or software failures/causes among incidents Each individual incident considered a small error or oversight that led to total loss of mission Cost of these failures to various users/customers: Over $3 billion! Failures initiated president s broad area review 13

14 WHO DOES SYSTEMS ENGINEERING? All Members of a Multi-disciplinary Team Engineering Quality Subcontract Management Business Management Etc. Everyone involved with development of a system should be a systemsthinker. Keep the end result in mind. Everyone should use a common framework (PROCESS) and language (REQUIREMENTS): Sees the forest amongst the trees Common language and plan 14

15 Science determines what IS.. Component Engineering determines what CAN BE.. Systems Engineering determines what SHOULD BE Systems engineering provides a systematic and orderly framework that should be accepted and used by all disciplines during the development of complex systems. 15

16 A SYSTEMS ENGINEER IS ONE WHO Orientation to customer (s) /stakeholder (s) Promotes broad-based thinking Practices a top down approach Recognizes the importance of processes Employs evolving innovative skills, techniques & tools Develops appreciation for the role of all disciplines and their integration (Facilitator/ Integrator) Acquires an experience base that prepares & motivates for greater individual responsibility Does the Right Things Right 16

17 GENERAL PRINCIPLES OF SYSTEMS ENGINEERING Know the problem Focus on purpose(s) Know the customer, ex. the consumer, the user, stakeholder expectations Discipline focus on the end product Use operational effectiveness criteria Establish and manage requirements and performance measures Verify requirements and validate system performance Identify and assess alternatives so as to converge on a solution Manage interfaces Perform risk management Maintain the integrity of the system Use an articulated and documented process Manage against the plan Corporate focus on continuous and process improvement and lessons learned 17

18 SYSTEMS ENGINEERING IS A PROCESS AS WELL AS A FIELD OF STUDY 18

19 APPLICATION OF SYSTEMS ENGINEERING Systems Engineering process & discipline applies to all programs Application & Balancing Considerations ( Art of Systems Engineering ) Size and complexity of the system Level of system definition detail Scenarios and missions Set of measures of effectiveness/metrics Known constraints and requirements Technology base Other factors related to major risk areas Enterprise best practices and strengths Cost, Schedule, and Risk 19

20 SUMMARY A system is a construct that produces results not obtained by its elements alone Systems Engineering competence is the fundamental skill needed in today s environment to provide a systematic and orderly framework that can be used by multiple disciplines during development of complex systems What you do upfront will have greatest impact on success/failure later on Somebody s system can be someone else s subsystem Systems Engineering is a process and a discipline (a field of study). Requirements key =f[customer, user, developer, life cycle view, program management effort] Systems engineering activity must be designed to manage risk and performance parameters Ensures exploration of a more comprehensive design space 20