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In this paper, a fuzzy logic controller equipped with training algorithms is developed such that the H tracking performance should be satisfied for a model-free nonlinear fractional order time delay system which is infinite dimensional in nature and time delay is a source of instability. In order to deal with the linguistic uncertainties caused from delay terms, the adaptive time delay fuzzy logic system is constructed to approximate the unknown time delay system functions. By incorporating Lyapunov stability criterion with H tracking design technique, the free parameters of the adaptive fuzzy controller can be tuned on line by output feedback control law and adaptive law. Moreover, the tracking error and external disturbance can be attenuated to arbitrary desired level. The numerical results show the effectiveness of the proposed adaptive H tracking scheme. [ABSTRACT FROM AUTHOR]

This paper proposes an adaptive fuzzy sliding mode control (AFSMC) to synchronize two different uncertain fractional-order time-delay chaotic systems, which are infinite dimensional in nature, and time delay is a source of instability. Because modeling the behavior of dynamical systems by fractional-order differential equations has more advantages than integer-order modeling, the adaptive time-delay fuzzy-logic system is constructed to approximate the unknown fractional-order time-delay-system functions. By using Lyapunov stability criterion, the free parameters of the adaptive fuzzy controller can be tuned online by output-feedback-control law and adaptive law. The sliding mode design procedure not only guarantees the stability and robustness of the proposed AFSMC, but it also guarantees that the external disturbance on the synchronization error can be attenuated. The simulation example is included to confirm validity and synchronization performance of the advocated design methodology. [ABSTRACT FROM AUTHOR]

Fuzzy control is a model free approach, i.e., it does not require a mathematical model of the system under control. An observer-based indirect adaptive fuzzy neural tracking control equipped with VSS and H∞ control algorithms is developed for nonlinear SISO systems involving plant uncertainties and external disturbances. Three important control methods, i.e., adaptive fuzzy neural control scheme, VSS control design and H∞ tracking theory, are combined to solve the robust nonlinear output tracking problem. A modified algebraic Riccati-like equation must be solved to compensate the effect of the approximation error via adaptive fuzzy neural system on the H∞ control. The overall adaptive scheme guarantees the stability of the resulting closed-loop system in the sense that all the states and signals are uniformly bounded and arbitrary small attenuation level of the external disturbance on the tracking error can be achieved. The simulation results confirm the validity and performance of the advocated design methodology. [Copyright &y& Elsevier]

As the rolling element bearing continues to soar in industry, the requirement for accurate bearing degradation prognostics becomes more and more crucial. A single Fuzzy predictor may suffer from its model parameters optimization. To this end, this paper proposed a new ensemble Fuzzy predictor model for estimating the degradation of a bearing using tribological responses among the rollers and the bearing races. This new method employs the genetic algorithm (GA) to assign an optimal weight vector to a set of adaptive network-based Fuzzy inference system (ANFIS) models. The ensemble of the predicted values of the ANFIS models is used as the prediction of the bearing degradation. Experimental data acquired from the degradation test of five rolling element bearings was used to evaluate the prediction performance of the proposed method. The analysis result demonstrates that the ensemble ANFIS model enables to improve the prediction accuracy against a single ANFIS one. The contribution of this paper is that the ensemble of the ANFIS models is not addressed in existing research and should be optimized. [ABSTRACT FROM AUTHOR]

Abstract Background and aims Cervical spondylosis (CS) is reported to be associated with vertebrobasilar insufficiency. However, few cohort studies have investigated the association between CS and posterior circulation ischemic stroke. Methods The study cohort comprised 27,990 patients aged ≥18 years with a first diagnosis of CS. The controls consisted of patients with propensity score matched for age, sex, and comorbidities at a ratio of 1:1. We investigated the relationships of CS with ischemic stroke and all-cause mortality. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). The average follow-up duration was 6.13 (SD = 3.18) and 6.07 (SD = 3.19) years in the CS and non-CS cohorts, respectively. Results The mean age of CS patients and non-CS patients was 54.9 ± 13.4 and 55.1 ± 14.9 years. Fifty-eight point five percent of CS patients and 59.2% of non-CS patients were women. CS patients were 1.46 folds more likely to develop a posterior circulation ischemic stroke (95% CI, 1.23–1.72) than non-CS patients. CS patients with myelopathy exhibited a 1.50–fold risk (95% CI, 1.21–1.86) of posterior circulation ischemic stroke compared with non-CS patients; CS patients without myelopathy were at a 1.43-fold risk (95% CI, 1.18–1.73) of posterior ischemic stroke compared with non-CS patients. The risk of posterior ischemic stroke was non-significant between non-CS patients and CS patients who had received spinal anterior decompression (adjusted HR, 1.66; 95% CI, 0.78–3.52), while receiving posterior decompression was associated with a 4.23-fold risk of posterior ischemic stroke (95% CI, 1.05–17.0). Conclusions This population-based study showed that CS is associated with an increased risk of posterior circulation ischemic stroke. Surgical posterior decompression was associated with the highest risk of posterior ischemic stroke. Highlights • CS patients were 1.46-fold more likely to develop a posterior circulation ischemic stroke than were the non-CS patients. • CS patients with myelopathy exhibited a 1.50-fold risk of posterior circulation ischemic stroke compared with non-CS patients. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed to inspect micro-lens size of optical connectors. In imaging, it can be found that the edge of a micro-lens and sharpness of the base image are different from the images of a square or straight edge. The edge of a micro-lens may be fuzzy and its gray scale distribution map may present a downtrend, making it difficult to identify the edge position. This study used a micro-lens with a diameter of 110μm as a basis reference. Furthermore, a high-precision AFM was used to obtain accurate values. The measured results were substituted into a newly proposed fuzzy ratio analysis method to deduce the fuzzy ratio and adjust edge fuzzy functions for further analysis of the micro lens edge in order to obtain more accurate results, which were used for the inspection of optical connectors to improve measurement accuracy. The experiment demonstrated that the error between the study results and the results of the commercial measurement system is lower than 1μm, and the inspection speed is faster. [Copyright &y& Elsevier]

Background and Aims: Cervical spondylosis (CS) is reported to be associated with increased sympathetic activity and hypertension. However, the cardiovascular (CV) outcomes of patients with CS are largely unknown., Methods: A national insurance claims dataset of 22 million enrollees in Taiwan during 1999-2010 was used as the research database. We identified 27,948 patients with CS and age-, sex-, and comorbidity-matched controls. By using multivariate logistic regression analysis after adjustment for potential cardiovascular (CV) confounders, we calculated odds ratios (ORs) with 95% confidence intervals (CIs) to quantify the association between CS and acute coronary syndrome (ACS)., Results: A total of 744 ACS events were identified among the 27,948 patients with CS. The overall incidence of ACS was 4.27 per 1000 person-years in the CS cohort and 3.90 per 1000 person-years in the non-CS cohort, with an adjusted hazard ratio (aHR) of 1.13 (95% CI = 1.08-1.18). The aHRs of ACS were 1.08 (95% CI = 1.03-1.15) in the CS cohort without myelopathy and 1.20 (95% CI = 1.13-1.28) in the CS cohort with myelopathy, compared with the non-CS cohort. Compared with patients with CS without neurological signs, patients with CS receiving rehabilitation exhibited a 0.67 aHRs of ACS (95% CI = 0.59-0.76), whereas those with neurological signs receiving spinal decompression exhibited 0.73 aHRs of ACS (95% CI = 0.63-0.84)., Conclusions: CS is associated with an increased risk of ACS. Receiving treatment for CS, either rehabilitation or spinal decompression, is associated with less risk of ACS., (Copyright © 2018 Elsevier B.V. All rights reserved.)

This paper presents a novel adaptive fuzzy logic controller (FLC) equipped with an adaptive algorithm to achieve H(∞) synchronization performance for uncertain fractional order chaotic systems. In order to handle the high level of uncertainties and noisy training data, a desired synchronization error can be attenuated to a prescribed level by incorporating fuzzy control design and H(∞) tracking approach. Based on a Lyapunov stability criterion, not only the performance of the proposed method is satisfying with an acceptable synchronization error level, but also a rather simple stability analysis is performed. The simulation results signify the effectiveness of the proposed control scheme., (Copyright © 2011 ISA. Published by Elsevier Ltd. All rights reserved.)

A new hybrid direct/indirect adaptive fuzzy neural network (FNN) controller with a state observer and supervisory controller for a class of uncertain nonlinear dynamic systems is developed in this paper. The hybrid adaptive FNN controller, the free parameters of which can be tuned on-line by an observer-based output feedback control law and adaptive law, is a combination of direct and indirect adaptive FNN controllers. A weighting factor, which can be adjusted by the tradeoff between plant knowledge and control knowledge, is adopted to sum together the control efforts from indirect adaptive FNN controller and direct adaptive FNN controller. Furthermore, a supervisory controller is appended into the FNN controller to force the state to be within the constraint set. Therefore, if the FNN controller cannot maintain the stability, the supervisory controller starts working to guarantee stability. On the other hand, if the FNN controller works well, the supervisory controller will be deactivated. The overall adaptive scheme guarantees the global stability of the resulting closed-loop system in the sense that all signals involved are uniformly bounded. Two nonlinear systems, namely, inverted pendulum system and Chua's (1989) chaotic circuit, are fully illustrated to track sinusoidal signals. The resulting hybrid direct/indirect FNN control systems show better performances, i.e., tracking error and control effort can be made smaller and it is more flexible during the design process.