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In this paper, a robust active fault tolerant control (AFTC) scheme is proposed for induction motor drives (IMD) via input-output linearization control (IOLC) and nonlinear observer. In order to estimate the states and to reconstruct the faults, two different observers are used; a Luenberger observer (LO) and an extended kalman filter (EKF). Further we introduce feedback linearization strategy by choosing the output function as the rotor speed and flux square. To provide a direct comparison between these FTCs schemes, the performance is evaluated using the control of IMD under failures, variable speed, and variable parameters, finally the obtained results show that the proposed controller with the proposed observers provides a good trajectory tracking, and these schemes are robust with respect to faults, parameter variations, and external load disturbances for induction motor drive system.

Background: Efforts to improve alternative CD4 T-cell counting methods are critical to accelerate the implementation of HIV antiretroviral therapy in resources limited regions. Substituting liquid format reagents to eliminate cold-chain transportation and refrigerated storage with dry format reagents contributes to higher efficiency supply management solution especially for laboratories at remote locations. ReaMetrix has developed dry format reagent kits compatible with the FACSCount system, a dedicated flow cytometer for T-cell subset enumeration widely used in resource limited settings. A dual site collaborative study was designed to compare T-cell subsets using both the new dry format ReaMetrix reagent and the original BD Biosciences liquid reagents.Method: A total of 167 HIV positive samples prepared with Rea T Count (ReaMetrix) and FACSCount (BD Biosciences) reagents were analyzed using FACSCount Systems. To compare both methods, Bland-Altman, Pollock, Scott % similarity and correlation coefficient statistical analysis was applied. Immuno-Trol served as an assay processing control and quality indicator of interlaboratory and intralaboratory variation.Results: The mean bias and limits of agreement for CD4 T-cell measurements between Rea T Count and FACSCount reagents were 216 cells/ll (24.6%) and 274 to 143, respectively. The correlation obtained was 0.988 with a similarity of 97.9%. Between laboratory variation data was very good with %CV below 10%.Conclusion: The introduction of dry reagents permits the elimination of cold-chain transportation and the on-site refrigerated storage without compromise to assay quality. The substitution of dry reagents facilitates easier supply management practice that will assure wider access to quality HIV treatment. V C 2009 Clinical Cytometry Society

In this paper, a control algorithm based on Backstepping technique for differential drive mobile robot path tracking is developed. The use of backstepping theory to solve the problem of path tracking is relatively new in the field of mobile robots control. Numerical simulations were conducted to show the effectiveness of the proposed algorithms to solve the nonholonomic constraints of the mobile robot, and its ability to achieve satisfactory performance. The stability of the system is proven via Lyapunov theory.