Background: Flood is one of the most destructive natural disasters of climate change effects in West Africa. Flood risk occurrence is a combination of natural and anthropogenic factors, which calls for a better unders...
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A robust fuzzy control design based on gain and phase margins specifications for nonlinear systems, with time delay, via multiobjective genetic algorithm, in the continuous time domain, is proposed. A Fuzzy C-Means (F...
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A robust fuzzy control design based on gain and phase margins specifications for nonlinear systems, with time delay, via multiobjective genetic algorithm, in the continuous time domain, is proposed. A Fuzzy C-Means (FCM) clustering algorithm estimates the antecedent parameters and the rule number of a Takagi-Sugeno fuzzy model, through from input and output data of the process, whereas the least squares algorithm estimates the consequent parameters. A multiobjective genetic strategy is defined to tune the fuzzy controller parameters, so the gain and phase margins of the fuzzy control system are close to the specified ones. The fuzzy PID controller was implemented on a real time acquisition data platform and compared with the PID controller Ziegler Nichols. The results demonstrate the effectiveness and practical viability of the proposed methodology.
Spinal cord injury is damage to the spinal cord that results in loss of functions, causes muscle, joint and bone deficits, moreover it increases the muscle tone level. FEScycling is an alternative rehabilitation proce...
Spinal cord injury is damage to the spinal cord that results in loss of functions, causes muscle, joint and bone deficits, moreover it increases the muscle tone level. FEScycling is an alternative rehabilitation process to conserve the musculoskeletal system affected by the injury in the functional state. The aim of this study is to get the legs bilaterally synchronized by FES and compare MMG signal responses. The preliminary protocol consists of five consecutive contractions. The first and the last contractions were discarded and the three intermediate contractions were analyzed. A ratio between MMG values of muscle responses during propulsion and return of pedalling phases was calculated for each cycle and each leg. The applied FES profile consisted of pulse and burst on time of 250 us and 5 ms and frequencies of 1000 Hz and 20 Hz, respectively. Results showed that greater MMG RMS values tend to occur during the propulsion phase than in the return phase. MMG Z axis of RLL and MMG X axis of LLL were the axes that presented the greatest ratios. The MMG RMS signal showed that greater values tend to occur during the propulsion phase than in the return phase of the same thigh.
Upper airway structure is known to be affected in individuals with obstructive sleep apnea (OSA). In this pilot study, we investigated whether the changes of upper airway resistance (UAR) within a breathing phase, est...
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ISBN:
(纸本)9781424492695
Upper airway structure is known to be affected in individuals with obstructive sleep apnea (OSA). In this pilot study, we investigated whether the changes of upper airway resistance (UAR) within a breathing phase, estimated from tracheal breathing sounds and airflow, is a predictor of OSA severity. Tracheal breathing sounds and airflow of 15 individuals in three groups of mild, moderate and severe OSA during wakefulness, recorded in supine position, were used in this study. The grouping of the study subjects were done based on their apnea/hypopnea index (AHI) per hour, prospectively. The breathing sounds and airflow were recorded simultaneously with full overnight polysomnography (PSG) assessment. The sounds of 3 noise-free breathing cycles were extracted and sequestered into inspiratory and expiratory phase segments manually for each study subject. The power spectra of the sound signals of each respiratory phase were calculated in 15ms windows with 50% overlap between adjacent windows. The UAR was then estimated as the ratio of the energy of power spectrum of each window within 100 to 2500 Hz, and its corresponding airflow. Then, the variance of the short-time windows' UAR, Var(UAR) during each respiratory phase was calculated. The ratio of the Var(UAR) in logarithmic scale between inspiration and expiration was found to be significantly different (p<0.01) between the three OSA groups;also it was found to be highly correlated with AHL These results are congruent with the hypothesis that the upper airway patency is not kept constant in OSA population, and suggest the change in acoustic UAR during wakefulness maybe considered as a predictor of OSA.
This paper proposes a new application based on fuzzy logic to search the optimal Step Size of the Normalized Least Mean Square (NLMS) algorithm for beamforming systems. The searching of the step size depends on the fu...
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ISBN:
(纸本)9781479984992
This paper proposes a new application based on fuzzy logic to search the optimal Step Size of the Normalized Least Mean Square (NLMS) algorithm for beamforming systems. The searching of the step size depends on the fuzzy inference results of an estimation of the final value of the cost function (J_E) instead of using its instantaneous value. The update of the step-size is performed outside of the adaptive algorithm and given it feedback by the fuzzy inference system;therefore the step-size is still fixed for the NLMS algorithm but variable for the complete searching scheme. Simulation experimental results show that a useful approximation of the optimal step-size can be obtained for different conditions of signal-to-noise plus interference ratios (SINR) and the minimization of the mean square error for the adaptive beamforming algorithm is also achieved.
After publication of the original article [1] it was noted that the name of author, D. Luke Fisher, was erroneously typeset in both the PDF and online formats of the manuscript as Luke D. Fisher.
After publication of the original article [1] it was noted that the name of author, D. Luke Fisher, was erroneously typeset in both the PDF and online formats of the manuscript as Luke D. Fisher.
In this paper we present a controller that achieves global input-to-state stability for a linear system of arbitrary relative degree, subjected to matched and unmatched disturbances. This controller combines the prope...
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ISBN:
(纸本)9781467371605
In this paper we present a controller that achieves global input-to-state stability for a linear system of arbitrary relative degree, subjected to matched and unmatched disturbances. This controller combines the properties of a discontinuous term, and a linear one, enforcing a conventional sliding mode using only partial state information. A direct and simple way of choosing the gains for this controller is also provided.
Human platelet lysates (HPLs), obtained from therapeutic-grade platelet concentrates (PC), are rich in growth factors and other bioactive molecules. HPL is increasingly evaluated as a substitute for foetal bovine seru...
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Human platelet lysates (HPLs), obtained from therapeutic-grade platelet concentrates (PC), are rich in growth factors and other bioactive molecules. HPL is increasingly evaluated as a substitute for foetal bovine serum (FBS), to likely become the next ‘gold standard’ supplement of growth media for clinical-grade ex vivo propagation of human cells. HPL avoids the risks of immunological reactions against xenoproteins. HPL quality and safety benefit from the pathogen safety measures in place for producing PC for transfusion. Numerous studies support that HPL-expanded mesenchymal stromal cells show improved proliferation and decreased doubling time than when using FBS-supplemented media and maintain characteristic immunophenotype, differentiation capacity and T-cell immunosuppressive effect. Several methods are used to prepare HPL; they differ in the selection and formulation of the starting PC, the consideration or not for blood groups, the pool size, the membrane lysis procedure, the depletion of fibrinogen, and the implementation or not of a pathogen inactivation step on PC materials or during manufacture. Allogeneic ‘off-the-shelf’ pooled HPLs, made from approximately fifty, or more, PC, are currently produced by blood establishments and/or available through commercial suppliers. Improved HPL standardization and safety profile, through larger pools and dedicated viral inactivation and removal treatments, is expected in the next few years, broadening applications in cell therapy and regenerative medicine. Systematic studies of the impact of the mode of production of HPL on the isolation and expansion of various human cell types should be encouraged.
Background: Decades of steady improvements in life expectancy in Europe slowed down from around 2011, well before the COVID-19 pandemic, for reasons which remain disputed. We aimed to assess how changes in risk factor...
Background: Decades of steady improvements in life expectancy in Europe slowed down from around 2011, well before the COVID-19 pandemic, for reasons which remain disputed. We aimed to assess how changes in risk factors and cause-specific death rates in different European countries related to changes in life expectancy in those countries before and during the COVID-19 pandemic. Methods: We used data and methods from the Global Burden of Diseases, Injuries, and Risk Factors Study 2021 to compare changes in life expectancy at birth, causes of death, and population exposure to risk factors in 16 European Economic Area countries (Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, and Sweden) and the four UK nations (England, Northern Ireland, Scotland, and Wales) for three time periods: 1990–2011, 2011–19, and 2019–21. Changes in life expectancy and causes of death were estimated with an established life expectancy cause-specific decomposition method, and compared with summary exposure values of risk factors for the major causes of death influencing life expectancy. Findings: All countries showed mean annual improvements in life expectancy in both 1990–2011 (overall mean 0·23 years [95% uncertainty interval [UI] 0·23 to 0·24]) and 2011–19 (overall mean 0·15 years [0·13 to 0·16]). The rate of improvement was lower in 2011–19 than in 1990–2011 in all countries except for Norway, where the mean annual increase in life expectancy rose from 0·21 years (95% UI 0·20 to 0·22) in 1990–2011 to 0·23 years (0·21 to 0·26) in 2011–19 (difference of 0·03 years). In other countries, the difference in mean annual improvement between these periods ranged from –0·01 years in Iceland (0·19 years [95% UI 0·16 to 0·21] vs 0·18 years [0·09 to 0·26]), to –0·18 years in England (0·25 years [0·24 to 0·25] vs 0·07 years [0·06 to 0·08]). In 2019–21, there was an overall decrease in mean annual life expectancy a
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