Etude exacte des conditions de convergence des égaliseurs

Il s'agit de déterminer les conditions de convergence pour un égaliseur adaptatif transverse et de longueur finie travaillant en phase d'apprentissage optimisé avec l'algorithme du gradient stochastique dans le cas d'un canal transverse d'ordre fini. Ceci traite la convergence en moyenne, en moyenne quadratique et la convergence presque sûre. On a pu déterminer une borne suffisante sur le pas d'adaptation critique (le pas à partir duquel l'algorithme diverge) pour différents types de canaux avec ou sans bruit. On a pu mettre en cause l'approche classique en comparant sa borne avec la borne exacte

[Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Sfax-Tunisia (1993-1998)].

&lt;p&gt;Antimicrobial susceptibility and frequency of occurrence of clinical blood isolates in Sfax-Tunisia (1993-1998). The choice of antimicrobial therapy for the treatment of bacteremia is often empirical and based on the knowledge of susceptibility profiles of the most common bacteria causing such infections. This study determines the bacterial etiology of bacteremic episodes and antimicrobial susceptibility patterns recorded at a teaching hospital, from January 1993 to December 1998. We collected 2979 strains responsible for bacteremia. Gram negative bacteria were predominant (60%). The organisms recovered most frequently were Staphylococcus aureus (18.9%), Escherichia coli (14.7%), Klebsiella pneumoniae (14%) and Pseudomonas aeruginosa (7.6%). The incidence of resistance to methicillin were 17.4% for Staphylococcus aureus and 26.8% for coagulase negative Staphylococcus. No resistance to glycopeptides was observed among the enterococci and staphylococci studied. 27.7% of enterobacteriaceae were resistant to third generation cephalosporins. Imipenem was the most active agent against gram negative bacteria. To carry out a surveillance of bacteremic episodes occurring at every hospital, it is necessary to provide valuable information which should be the basis for effective empiric therapy.&lt;/p&gt;</p