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X Scuola Nazionale CIRA di dottorato “Antonio Ruberti” Bertinoro, 10-12 Luglio 2006. I Sistemi Positivi Realizzazione: esistenza a tempo continuo e minimalità. Lorenzo Farina Dipartimento di informatica e sistemistica “A. Ruberti” Università di Roma “La Sapienza”, Italy.
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X Scuola Nazionale CIRA di dottorato “Antonio Ruberti” Bertinoro, 10-12 Luglio 2006 I Sistemi PositiviRealizzazione: esistenza a tempo continuo e minimalità Lorenzo FarinaDipartimento di informatica e sistemistica “A. Ruberti”Università di Roma “La Sapienza”, Italy
The positive realization problem for continuous-time systems Spectrum translation property
Examples - I … not to be!
Examples - II … not to be!
Does positive factorization suffice? For general systems, the minimal inner dimension of a factorization of the Hankel matrix coincides with the minimal order of a realization. Is that true also for positive systems?
Does positive factorization suffice? No rotational simmetry, no 3rd order positive realization...
Does positive factorization suffice? No! A positive factorization of the Hankel matrix!
A prologue via examples (I) (contd.) The spectrum must remain unchanged under a rotation of /2(q+1) radians
A prologue via examples (I) The spectrum must remain unchanged under a rotation of /4 radians
The Karpelevich regions n = 4 n = 3
A prologue via examples (II) hidden pole
2 3 Ab Ab b @O Ab cx = 0 2 3 cAx = 0 cAx = 0 cAx = 0
Minimality of Positive SystemsNSC for 3rd order systems (contd.) r3 r2 {1 {1
Minimality of Positive SystemsNSC for 3rd order systems (contd.)
Minimality of Positive SystemsNSC for 3rd order systems (contd.)
Minimality of Positive SystemsNSC for 3rd order systems (contd.)