Post on 15-Apr-2017
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Rolando Brondolin rolando.brondolin@mail.polimi.itLucaCerina luca.cerina@mail.polimi.itAlessandra Fusco alessandra1.fusco@mail.polimi.it
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Focus on NMF (2)
GivenanonnegativematrixA� Rm×n andapositiveintegerk<min{m,n}findnonnegativematricesW� Rm×k andH� Rk×n tominimizethefunctional:
Img:Cheung,VincentCK,etal. "Musclesynergypatternsasphysiologicalmarkersofmotorcorticaldamage."ProceedingsoftheNationalAcademyofSciences 109.36(2012):14652-14656.
A->EMGsampledsignal,W->MuscleSynergy,H->Time-varyingactivation
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NMFheuristicsiterativelyupdatesWandHandconvergestoalocaloptimalsolution,checkingateachstepthevalueofthecostfunction.Polynomial time[1],butstillexpensive!
[1]Vavasis,StephenA."Onthecomplexityofnonnegativematrix factorization."SIAMJournalonOptimization 20.3(2009):1364-1377.
FPGAs• Highpower• Low energy consumption• Difficult todevelop• Real-timeNMFfeasible with
acceptable energy costs
Microprocessors• Highpower• HighEnergyconsumption• Real-timeNMFfeasible but at
highenergy cost
Microcontrollers• Low power• Low Energy• Real-timeNMFnot feasible on
site,external CPUis needed
Chosen architecture