Kalle M. Mikkola

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We obtain state-space formulas for the solution of the Nehari-Takagi/sub-optimal Hankel norm approximation problem for infinite-dimensional systems with a nonexponentially stable generator, via the method of J-spectral factorization. We make key use of a purely frequency domain solution of the problem. AMS mathematical subject classification numbers: 41A30,(More)
STUDY OBJECTIVES To determine the risk factors and frequency of intracranial hemorrhage among patients undergoing thrombolysis for pulmonary embolism. DESIGN A retrospective descriptive and controlled analysis. SETTING Hospitalized patients at centers in the United States, Canada, and Italy. PATIENTS All had evidence of pulmonary embolism on perfusion(More)
It is known that a matrix-valued transfer function P has a stabilizing dynamic controller Q (i.e., h I −Q −P I i−1 ∈ H∞) iff P has a right (or left) coprime factorization. We show that the same result is true in the operator-valued case. Thus, the standard Youla–Bongiorno parameterization applies to every dynamically stabilizable function. We then derive(More)
We reviewed our database of 312 patients with pulmonary embolism who received thrombolysis in five clinical trials. At baseline, none had a history of stroke, internal bleeding within 6 months, surgery within 10 days, or occult blood in stool. Sixty-six major bleeding episodes occurred within 72 hours of administering thrombolysis in 61 (20%) patients:(More)
The efficacy and safety of thrombolysis in patients with cancer with pulmonary embolism is uncertain. Therefore we studied the effects of thrombolysis in 57 patients with cancer and 254 patients without cancer who were treated in five clinical trials with tissue plasminogen activator or urokinase for pulmonary embolism. Immediately after thrombolysis, the(More)
Activated protein C resistance caused by factor V Leiden mutation is the most common inherited cause of an underlying predisposition to pulmonary embolism (PE) and deep venous thrombosis (DVT). We studied the frequency of the factor V Leiden mutation in 50 women who had PE and/or DVT during or after pregnancy or during oral contraceptive use. Ten (20%; 95%(More)
We compute the Bass stable rank and the topological stable rank of several convolution Banach algebras of complex measures on (−∞,∞) or on [0,∞) consisting of a discrete measure (modelling delays, possibly commensurate or having n generators) and/or of an absolutely continuous measure (an L function). We also compute the stable ranks of the convolution(More)