In this paper, we consider design of H ∞ feedback control systems with quantized signals. We first assume that a state feedback has been designed for a continuous-time LTI system so that the closed-loop system is (Hurwitz) stable and a desired H ∞ disturbance attenuation level is achieved, and that the states are quantized before they are passed to the controller. We propose a statedependent strategy for updating the quantizer's parameter, so that the system is asymptotically stable and achieves the same H ∞ disturbance attenuation level. We then extend the result to the case of observer-based dynamic output feedback where the measurement outputs are quantized, and propose an output-dependent strategy for updating the quantizer's parameter.

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Aims:We aimed to test the hypothesis that the presence of in-stent yellow plaque (YP) assessed by angioscopy would be a risk of very late stent failure (VLSF) of the cobalt-chromium everolimus-eluting stent (CoCr-EES) in comparison with first-generation drug-eluting stents (DES).Methods and results: DESNOTE-X was a prospective cohort study, an extended study of the DESNOTE study (UMIN000013515). All patients who received successful angioscopic examination at planned oneyear follow-up of DES were clinically followed. The primary endpoint was VLSF defined as a composite of cardiac death, target vessel myocardial infarction, and target lesion revascularisation. A total of 504 patients with 549 lesions were enrolled over a period of 12.5 years. At one-year follow-up, the incidence of YP was significantly higher in the first-generation DES than in the CoCr-EES (199/292 [68%] vs 80/257 [31%], p<0.001). Maximum yellow colour grade on coronary angioscopy at one-year follow-up was an independent predictor of future VLSF in the first-generation DES (HR 2.604 [95% CI: 1.265-5.361], p=0.009), whereas it was not in the CoCr-EES (p for interaction 0.022). Conclusions:The incidence of in-stent atherosclerosis identified as YP on angioscopy was lower and its impact on late clinical events appeared smaller in the CoCr-EES than in the first-generation DES.

In this paper, we consider stability analysis and design for switched systems consisting of linear discrete-time descriptor subsystems. When all descriptor subsystems are stable, we show that if the descriptor matrix and all the subsystem matrices are commutative pairwise, then the switched system is stable under arbitrary switching. We also extend the result to the case where all subsystems have different descriptor matrices. Under the same commutation condition, we show that in the case where none of the descriptor subsystems is stable, if there is a stable combination of the unstable descriptor subsystems, then we establish a class of switching laws which stabilize the switched descriptor system. All the results are natural but important extensions to the existing results for switched systems composed of state space subsystems.

In this paper, we consider stability analysis and design for switched systems consisting of linear descriptor systems that have the same descriptor matrix. When all descriptor systems are stable, we show that if the descriptor matrix and all the system matrices are commutative pairwise, then the switched system is stable under arbitrary switching. This is an extension of the existing well known result in [1] for switched linear systems with state space models to switched descriptor systems. Under the same commutation condition, we also show that in the case where all descriptor systems are not stable, if there is a stable convex combination of the unstable descriptor systems, then we can establish a class of switching laws which stabilize the switched system. We finally make some discussion about obtaining the stable convex combination by solving a matrix inequality efficiently, and about relaxing the commutation condition for stabilizability of the switched system.