Youmin Zhang

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In this paper, a bibliographical review on reconfigurable (active) fault-tolerant control systems (FTCS) is presented. The existing approaches to fault detection and diagnosis (FDD) and fault-tolerant control (FTC) in a general framework of active fault-tolerant control systems (AFTCS) are considered and classified according to different criteria such as(More)
Multiple-model (MM) estimation, as a powerful approach to adaptive estimation, has received a great deal of attention in recent years due to its unique power to handle problems with both structural and parametric uncertainties and/or changes, and to decompose a complex problem into simpler subproblems. In his Bode Lecture given at the 1995 IEEE Conference(More)
The stochastic stability of fault tolerant control systems (FTCSs) in the presence of noise has been analyzed using the Lyapunov function approach. In particular, FTCS with a Markovian fault detection and isolation (FDI) process with transition probabilities conditioned on the state of another Markovian process representing component failures are(More)
Macrophages play crucial roles in the formation of atherosclerotic lesions. Akt, a serine/threonine protein kinase B, is vital for cell proliferation, migration, and survival. Macrophages express three Akt isoforms, Akt1, Akt2, and Akt3, but the roles of Akt1 and Akt2 in atherosclerosis in vivo remain unclear. To dissect the impact of macrophage Akt1 and(More)
OBJECTIVE The balance between apoptosis susceptibility and efferocytosis of macrophages is central to plaque remodeling and inflammation. LRP-1 and its ligand, apolipoprotein E, have been implicated in efferocytosis and apoptosis in some cell types. We investigated the involvement of the macrophage LRP-1/apolipoprotein E axis in controlling plaque apoptosis(More)
A fast learning algorithm for training multilayer feedforward neural networks (FNN's) by using a fading memory extended Kalman filter (FMEKF) is presented first, along with a technique using a self-adjusting time-varying forgetting factor. Then a U-D factorization-based FMEKF is proposed to further improve the learning rate and accuracy of the FNN. In(More)
A novel fault-tolerant control system design technique has been proposed in this paper, which blends the multiple-model principle with the unavoidable performance degradation due to faults in actuators, sensors or system dynamics. The number of models employed depends on the characteristics of the system, the nature of the failures considered, and the(More)
In this paper, the classical least squares (LS) and recursive least squares (RLS) for parameter estimation have been re-examined in the light of the present day computing capabilities. It has been demonstrated that for linear time-invariant systems, the performance of blockwise least squares (BLS) is always superior to that of RLS. In the context of(More)
Advanced fault detection and accommodation schemes are required for ensuring efficient and reliable operation of modern wind turbines. This paper presents a novel approach in designing a fault detection and diagnosis (FDD) and fault-tolerant control (FTC) scheme for a wind turbine using fuzzy modeling, identification and control techniques. First, an(More)