1. Optimization: Technical Performance Allocation
EMIS 8340
Systems Engineering Tool—applying tools to engineering systems
Optimization: Technical Performance Allocation
Mark E. Sampson

2. Allocatable (Weight, Cost,…)
Requirement Types…
Allocatable (Weight, Cost,…)
Non-Allocatable (material/process standards that apply to everything)
…shall be painted green
…shall be written in Mil-Std 1750 compliant ADA
…let’s talk about the interesting ones…
[DSMC ]

3. Requirements Allocation…the big picture
Captured requirements…
Linking requirement to functions…
Functions linked to physical alternatives/architectures…
…keep going until realizable
…requirements flow thru system & documented in allocation matrix R R R R R
Battery
Motor
Processor
Drive
Allocation Matrix
R Func1 Battery
R Battery
R Func2 Motor
[SE Handbook 9.2 ] [DSMC ]

4. Technical Budgets/Targets/Design Constraints
Come from external interfaces, drivers, constraints…
“How much” coming from functions
Allocated/divided up among design alternatives
Quantifiable requirements like:
weight
power
thru-put
cost
error …
Example allocation flow-down:
System-transmit collected data in real time to remote ground site
Segment-provide wideband data link from spacecraft to relay
Element-provide 10Mhz link at 17Ghz
Sub-system-provide 10Mhz link at 17Ghz with 10W effective radiated power for 20 minutes per orbit revolution
[SE Handbook 9.2.2]
[Lacy 1992]

5. Flowing-down Technical Budgets/Constraints…
Tools are an important part of this process...
Math Models
Excel
Tracing tools with extensions…
A few SE tools include integrated budgeting (SLATE, Cradle-SEE,…)
SLATE Technical Budgeting Demo…
[SE Handbook 9.2.2] [DSMC ]

6. Costing…Design to Cost, Life Cycle Costing,…
Predicting the cost of your system
Using it as critical parameter for choosing alternatives
Apparently we aren’t very good at predicting how much something will cost…particularly in software:
GAO: “only 2% of software is usable exactly as delivered”
Standish: “53% of projects will cost 189% of estimates”
…either we are poor at executing or we are poor at estimating
Engineered Costing relies on bottom-up rollups of tasks, etc.
Analogs—just like this other one
Rules-of-thumb—test costs 25% of manufacturing
Validated/Modeled rules-of-thumb— Parametric Cost Estimation Models
[ [DSMC ]

7. Costing…Parametric Cost Estimation
Identifies Cost Estimating Relationships (CERs) & “logic” among those relationships to estimate costs.
Cost Estimates are then validated/tested using statistical techniques
A number of hardware/software cost models have been created:
Price-H,-S,… (LMCO)
REVIC
COCOMO
AMCM--missions
SoftCost-R
…and a systems model is under development…
COSYSMO Dr. Barry Boehm (USC) Dr. Richardo Valerdi (MIT/UofA) Present/Demo
Unmanned Mission Non-recurring Cost Model [