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Specialty Engineering as an Element of Systems Engineering. INCOSE MEETING (Enchantment Chapter) August 9, 2006. Murray Elowitz JJ & E Research Corp 11045 Greenview NE Albuquerque, NM 87111 (505) 856-7247 melowitz@comcast.net. Purpose.
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Specialty Engineering as an Element of Systems Engineering INCOSE MEETING (Enchantment Chapter) August 9, 2006 Murray Elowitz JJ & E Research Corp 11045 Greenview NE Albuquerque, NM 87111 (505) 856-7247 melowitz@comcast.net
Purpose To discuss how System Engineers include SPECIALTY ENGINEERINGin their project • Defining Specialty Engineering • Where it fits into System Engineering • Example 1: Meeting spec • Example 2: More subtle Goal: Maximize effectiveness of specialties to support program success M. Elowitz
Defining Specialty Engineering • Murray’s Definition (Today’s version) – Specialty Engineering is the collection of those narrow disciplines that are needed to engineer a complete system Some specialty engineering has deliverable functional products, Some specialty engineering is analytic. Exercise for the student – define products of each specialty M. Elowitz
What are specialties SAMPLE LIST (For integrated hardware/software/data systems) • RELIABILITY, MAINTAINABILITY, AVAILABILITY • Human Factors • Safety • Electromagnetic Effects • Facilities Some people include • Logistics Exercise for the student – Name other specialties M. Elowitz
Definitions M. Elowitz
Typical Org Chart Specialties under System Engineering - Allows careful direction to get to needed results M. Elowitz
Characteristics • Why distinguish the specialties from System Engineering? • Usually a narrow discipline; e.g., RMA • In project team, hard to level load manpower • Practitioners usually want their own identity • Why place specialties under System Engineering? • For early phases (Concept Definition through DemVal) • SE needs to control or task the specialties • Knows where the problems and issues are • Understands and performs top-level trades Exercise for the student – Give more reasons M. Elowitz
System Requirements System Design System Analysis Specialty Require Specialty Design Specialty Analysis In System Engineering Process Preliminary Design Specialty Des, Anal M. Elowitz
Example 1: Meeting spec • Critical Requirement is reliability of commercial aircraft • After initial modeling, AVIONICS is critical segment Model Reliability Add Detail Reliability Add Detail Reliability OK Meets Specs Design Design Iteration Design Iteration Reflect results • Two sides to iteration • Underdesign drives loss of sales • Underdesign drives warranty costs • Overdesign drives cost, possibility • loss of sales Did Not Meet Specs Did Not Meet Specs M. Elowitz
Look up Failure Rates Present Model System Crunch Reliability Handbook Process Examples of the kind of system level trades needed instantly System engineer needs special studies What is sensitivity of R to tolerance on controlled temperature? If tightening up on Temp increases vibration, what is system R? If we replace component C with a cheaper one, but use redundancy, will we still meet R spec? M. Elowitz
Example 2: More subtle • Availability – Requires reliability calculations and corresponding MTTR’s • What if the baseline design makes component K hard to replace, creating a large MTTR? • System tradeoffs may involve lowering MTTR on other components, improving R of component K or others, major design changes to lower K’s MTTR, and so on (and on) • System engineer needs to direct Specialty Engineering to solve the right problem • Then SE may need to address whether spec is reasonable M. Elowitz
System Engineering Golden Rules M. Elowitz
Summary • In the early phases of a program, System Engineering needs tight control over Specialties • Needs to direct resources • Needs to prioritize • Needs responsiveness • Putting Specialties under System Engineer provides needed control • System Engineer needs to know the capabilities and limitations of each specialty M. Elowitz