June 06, 2008
Everything you ever wanted to know but were afraid to ask.
Abstract
"Do you have issues with your customers that don't understand the differences between "Wants and Needs", "Objectives and Goals" and "Requirements"? Do you have top level requirements that don't fully trace to software requirements? Do you problems dealing with COTS requirements? Learn how the Incremental Commitment Model can help!
The presentation will start with a refresher on the Incremental Commitment Model, including the many overlaps with requirements. Next, SysML's Requirements "Modeling" capabilities will be discussed, including roles of Activity Diagrams, Use Cases, Requirements and Parameter Diagrams, and the cross-cutting concepts that link SysML diagrams related to behavior with those that represent structure. The abilities of some SysML tools' with respect to Model Checking, and State Machine execution (for operational concepts validation through simulation) will also be presented.
Following the level setting introductory material, the "Requirements" conundrums will be addressed, including why there is only one word for all levels of "requirements"; COTS (especially software) putting the cart before the horse; and bringing in the software people too late, especially in Software Intensive Systems, but also just with systems with both hardware and software components. Over the lifecycle of a system, especially the early parts, systems engineers should be talking about "Wants and Needs", followed closely with slightly more precise "Objectives and Goals" and more concretely negotiated "Win Conditions". These finally get refined into explicit system requirements for functionality (AKA capabilities) and performance (AKA levels of service), AND constraints and derived requirements that often come from the "Win Conditions". The previous refinements are then repeated at the sub-system and software levels. But a top-down, functional decomposition can often lead to "requirements" at lower levels that are impossible to achieve: how can they be called "requirements"?
Finally, a group discussion will take place to try to identify scenarios of requirements specification that do not seem to have been addressed by the foregoing concepts. This will be of great assistance to CSSE as we try to tackle this non-trivial problem. Remember, at least for software, the effort spent to detect and fix a requirements defect during the requirements specification activity can be .01 to .001 times the cost, or higher, if it is not detected until "testing". What is that ratio for systems requirements?
Your Presenter: A. Winsor Brown is an Instructor for the Computer Science and Systems Architecting and Engineering Departments, and Assistant Director of the Center for Systems and Software Engineering, University of Southern California.
Winsor Brown has extensive experience in software engineering, including architecture, process improvement, and training. He has a Master of Science in Electrical Engineering from California Institute of Technology and a Bachelor of Engineering Science from Rensselaer Polytechnic Institute. Prior to joining USC's CSSE as Assistant Director, Winsor had over 30 years of experience in software development, software engineering and software engineering management; it was gained through aerospace, industrial and commercial applications. During his career, Winsor has been involved in such programs as Barclays Global Investors Core PM system, the Future Combat System, FAA's Enroute Automation Modernization, International Space Station SEPG, and C-17 Software Program Management. He is a co-author of Software Cost Estimation with COCOMO II.
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Logistics
Location: Northrop Grumman E2 Presentation Center (in tall building off of Entrance 2), Redondo Beach, CA (formerly TRW) - 2299 Marine Ave., Redondo Beach, CA 90278
Directions: Take the 405 Inglewood exit (southbound it's the exit after Rosecrans East, northbound it's the exit just after Hawthorne) and go north on Inglewood Avenue (southbound, turn left at the end of the ramp, northbound, turn right). Turn left at Marine. Continue West under the freeway past the railroad tracks three lights to Simon Ramo Drive. E2 is on the tall white building to the LEFT, past the shorter presentation building. (See page 733 A5 of the Thomas Brothers Guide.)
Time: 9 a.m. - 12:00 noonAdmission: Free Reservations: No reservations are necessary, except for Foreign Nationals.
Please Note: Foreign Nationals, including Northrop Grumman
foreign employees, must contact Warren Scheinin
(warren.scheinin@ngc.com) at least three (3) days before
the meeting so NGC can process the paperwork for visits
in a NGC building in accordance with Department of
Defense regulations. The usual identification (passport,
green card, student visa) will be necessary on the visit
day.
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