Penn Fall DeHon Senior Design Skills and Advice September 27, 2013 Specification and Concept Generation

Message Don’t Panic –about solving everything at once –Employ wishful thinking Don’t get stuck on first idea –Generate many –Mix & Match –Get Systematic Evaluate ideas against constraints and priorities Penn Fall DeHon

Senior Design Intro Penn Fall DeHon

Engineering Design Methodology Problem Definition Requirement Ident. and Analysis –Priorities Specification Problem Decomp. Concept Generation –Brainstorming Modeling Parameterization and Design-Space Exploration Benchmarking Concept Selection Prototyping Implementation Testing Debugging Evaluation

Engineering Design Methodology Problem Definition Requirement Ident. and Analysis –Priorities Specification Problem Decomp. Concept Generation –Brainstorming Modeling Parameterization and Design-Space Exploration Benchmarking Concept Selection Prototyping Implementation Testing Debugging Evaluation

Penn Fall DeHon Specification Before can start solving –Need to know what your solving Before can evaluate “goodness” –Need to know what trying to accomplish –Priorities

Penn Fall DeHon Quantitative Specification Typically need to –turn vague specification –into something quantifiable/measurable Something concrete From: fast packet processing –To: process 700B packets at Gb/s – added latency of 15 microseconds

Penn Fall DeHon Specifications More of a trick/challenge for things that don’t have natural metrics –From: Door closes easily –To: Door latches with <5 lbs. Of force… –From: reliable –To: 1 failure in 10 9 hours of operation 1 undetected failure …

Penn Fall DeHon Establish Priorities Which requirement is king? Which have flexibility? –Can tradeoff? Ex: Requirements – quad rotor –Cost in Volume (<$200) –Battery Life (>15 minutes of flying) –Payload (up to 1 kg)

Penn Fall DeHon Establish Targets Acceptable Ranges Ideal Usually Relative to alternatives/competitors Problem formulation should capture priorities

Penn Fall DeHon RotoRouter Targets and Priorities Starting Point –Support TCP/IP –Operate with Introduction Based Routing –Logic fit in NetFPGA (gates, memory) Cryptographic hardware couldn’t be too large –Run at Gb/s line rate Cryptographic hardware must be fast –Detect and limit “bad” traffic Less than 10% impact on “good” traffic –Prevent tampering with packets

Penn Fall DeHon Concept Generation

Penn Fall DeHon Goal of Concept Generation Fully explore design space –Not miss options –Open minds to possibilities –Know what we can do Competitors can do

Penn Fall DeHon Components Structured Approach Partial Solutions Uncertainty/Unknown Documentation

Penn Fall DeHon Non-Atomic Insight Nothing will ever be attempted, if all possible objections must be first overcome. --- Samuel Johnson, 1759.

Penn Fall DeHon Uncertainty “Do you remember what I have taught you? Most intelligent beings prefer to live in certainty than uncertainty. Rather than accept uncertainty, they will discount the input of their own senses. It is through this mechanism that mages manipulate the perception of others.” --- Elric to Galen upon his [Elric's] death Invoking the Darkness, Jeanne Cavelos

Penn Fall DeHon Concept Generation: Steps Start refined problem specification 1.Clarify/decompose 2.Search –Externally –Internally / brainstorm 3.Explore Systematically 4.Reflect

Penn Fall DeHon Decompose Separate components must solve –Divide and conquer Maybe attack w/ separate passes through process Focus on bottleneck –Critical path/subproblem –Where most risk is Most innovation needed

Router Decompose Decide where packet needs to go Switch packet Ensure integrity Ensure privacy Validate packet wanted by destination Penn Fall DeHon

Quad Rotor Decompose Propulsion Location – how know where you are Energy supply Control and Stabilize Motion Control Route Planning Payload pickup and hold Penn Fall DeHon

Search Externally Literature –Published / library –Web….google, IEEE DL, ACM DL –Patents Customers Experts (faculty/research labs, advisors, industry contacts) Benchmark related / competitive Understand state-of-art

Penn Fall DeHon Search Internally/Brainstorm Common bugs: –Reject things too early “Nothing…” quote –Latch onto few ideas Get stuck in own local minima

Penn Fall DeHon Search Internally/Brainstorm Different mode of thinking Generate lots of ideas Suspend judgment / no squashing Grow mode / acid mode Find good pieces, incomplete ideas Wishful thinking Comfortable with uncertainty

Penn Fall DeHon Brainstorm Throw out ideas Write them down … draw pictures De-personalize –Name by characteristics not person –Not attacking person/idea –Group ownership –Everyone contribute to debugging Friendly amendments Mix-and-match Good science –Find best ideas, avoid Not-Invented-Here syndrome

Penn Fall DeHon People and Brainstorming Good to have both individual and group thinking times More brains generally good –Maybe limit size of group at a time –Different perspectives good Group ownership of final product –Involve stake holders –Build confidence in conclusion –Get buy in

Penn Fall DeHon Systematic Exploration Parameterized Design Space –Knobs can turn to move between design points? Concept combination matrix Classification tree Goals: –Find holes –Over-emphasis –Make sure think about all cross products…

Penn Fall DeHon Reflect Throughout process Comfortable solving problem? –Specification adequate? Process

Message Don’t Panic –about solving everything at once –Employ wishful thinking Don’t get stuck on first idea –Generate many –Mix & Match –Get Systematic Evaluate ideas against constraints and priorities Penn Fall DeHon

Time Permitting Work on example(s) –Decompose –Brainstorm Penn Fall DeHon