A geometric theory for 2-D systems including notions of stabilisability

In this paper we consider the problem of internally and externally stabilising controlled invariant and output-nulling subspaces for two-dimensional (2-D) Fornasini–Marchesini models, via static feedback. A numerically tractable procedure for computing a stabilising feedback matrix is developed via linear matrix inequality techniques. This is subsequently applied to solve, for the first time, various 2-D disturbance decoupling problems subject to a closed-loop stability constraint

Geometric techniques for implicit two-dimensional systems

Geometric tools are developed for two-dimensional (2-D) models in an implicitFornasini–Marchesini form. In particular, the structural properties of controlled and conditionedinvariance are defined and studied. These properties are investigated in terms ofquarter-plane causal solutions of the implicit model given compatible boundary conditions.The definitions of controlled and conditioned invariance introduced, along with the correspondingoutput-nulling and input-containing subspaces, are shown to be richer than theone-dimensional counterparts. The analysis carried out in this paper establishes necessaryand sufficient conditions for the solvability of 2-D disturbance decoupling problems andunknown-input observation problems. The conditions obtained are expressed in terms ofoutput-nulling and input-containing subspaces, which can be computed recursively in a finitenumber of steps

Numerically reliable design for proportional and derivative state-feedback decoupling controller

10.1016/S0005-1098(02)00138-3Automatica38122121-2125ATCA

On the quadratic controllability and quadratic feedback minimality

10.1109/TAC.2002.802765IEEE Transactions on Automatic Control4791487-1491IETA

An implicit systems characterization of a class of impulsive linear switched control processes. Part 1: Modeling

International audienc

Decoupling of internal variable structure for a class of switched systems

International audienc

State feedback decoupling problem with stability for (a,b, c,d) quadruples

10.1137/070692716SIAM Journal on Matrix Analysis and Applications3041735-176

Decoupling of internal variable structure for a class of switched systems

International audienc

Diagnostic Value of Procalcitonin for Bacterial Infection in Elderly Patients in the Emergency Department

OBJECTIVES: To evaluate the diagnostic performance of procalcitonin (PCT) in elderly patients with bacterial infection in the emergency department (ED). DESIGN: Prospective. SETTING: ED of a tertiary care hospital. PARTICIPANTS: Elderly patients with systemic inflammatory response syndrome (SIRS) enrolled from September 2004 through August 2005. MEASUREMENTS: A serum sample for the measurement of PCT, two sets of blood cultures, and other cultures of relevant specimens from infection sites were collected in the ED. Two independent experts blinded to the PCT results classified the patients into bacterial infection and nonbacterial infection groups. RESULTS: Of the 262 patients with SIRS enrolled, 204 were classified as having bacterial infection and 48 as having bacteremia. PCT levels were significantly higher in patients with bacteremia than in those without. The area under the receiver operating characteristic curve for identification of bacteremia according to PCT was 0.817 for the old- old group (>or=75), significantly higher than 0.639 for the young-old group (65- 74); P=.02). The diagnostic sensitivity, specificity, positive predictive value, and negative predictive value of PCT for bacteremia in patients aged 75 and older were 96.0%, 68.3%, 33.8%, and 98.8%, respectively, with a PCT cutoff value of 0.38 ng/mL. CONCLUSION: PCT is sensitive for diagnosing bacteremia in elderly patients with SIRS at ED admission but is helpful in excluding bacteremia only in those aged 75 and older. PCT is not an independent predictor of local infections in these patients