Search

Background and Aims: Obese patients undergoing bariatric and metabolic surgeries have a high chance of respiratory depression and could need admission to an intensive care unit or a high-dependency unit. Several studies have compared remifentanil to other opioids or non-opioids in these patients. This review investigated the efficacy and safety of remifentanil in bariatric and metabolic surgeries. Methods: After registering with PROSPERO, we searched PubMed/Medline, Ovid, CINAHL and the Cochrane Library with relevant keywords to find studies in which remifentanil was compared to other opioids or non-opioids in adult patients undergoing bariatric and metabolic surgeries. We used the risk of bias-2 tool to assess bias and Grading of Recommendation, Assessment, Development and Evaluation to determine the level of evidence. RevMan 5.4 was used to perform a quantitative meta-analysis. Results: Of the 121 articles retrieved from the database search, seven articles fulfilled the inclusion criteria. The overall bias was low in five studies and high in two studies. There was significant heterogeneity in the control group, which comprised opioids and also non-opioids like labetalol, dexmedetomidine and lignocaine. A quantitative meta-analysis was not reported due to a lack of comparable data for a meaningful quantitative meta-analysis. Conclusion: The results of this systematic review neither support nor refute the use of remifentanil in patients undergoing bariatric and metabolic surgeries, compared to other medications. Further studies are needed to investigate its efficacy and safety in these patients. [ABSTRACT FROM AUTHOR]

This paper presents a new nonlinear fractional-order model identification of a two-level voltage source inverter fed induction motor (VSI-IM). The nonlinearities present in inverter and IM cause the failure of the sensorless controls and model predictive controls, which mainly depends on the VSI-IM model. In the proposed work, an attempt has been made to identify the exact nonlinear behavior of the VSI-IM model using the PWM signal injection method. The identified fractional-order VSI-IM model is helpful to provide more insight into the dynamic behavior of the IM drive in the speed controller design (sensorless and sensored) and in predictive controls (model-based and model-free). The fractional VSI-IM models are identified at low, medium, and high frequencies. The best fit of these models is compared to the integer-order identified VSI-IM models. The experimental study clearly shows that the fractional-order VSI-IM identified model is superior to the integer-order VSI-IM model in terms of best fit with the actual hardware speed response. [ABSTRACT FROM AUTHOR]

Although several studies have revealed that fractional order controllers usually outperform conventional integer-order control solutions, fractional order controllers are not yet widely applied in industrial applications due to their complex mathematical background. In this paper, further improvements of a simple weighted sum feedback design are introduced that imitates the behavior of a fractional order controller but is free from its various formal restrictions. The proposed control solution has the main characteristics of a fractional order controller, such as finite memory length, excellent transient response with no overshoot and robust behavior, but it is placed into a much simpler mathematical framework. In the current paper, a simple derivative term was incorporated in the design which made the controller's output more stable by completely eliminating output chattering. The proposed control method was developed for a general second-order system. It was tested in a fixed point iteration-based adaptive control scenario, through simulations using a robotic example and on experimental basis as well, utilizing a simple one-degree-of-freedom electromechanical system. The presented experiments are the first systematic investigations of the fixed point iteration-based adaptive control method. [ABSTRACT FROM AUTHOR]

Competing Interests: Conflicts of Interest, Funding: Please see DISCLOSURES at the end of this article.

In this technical communication a voltage differencing transconductance amplifier (VDTA)-based unified grounded fractional/integer order negative/positive inductance emulator (IE) has been proposed which can be configured as (i) fractional order negative inductance emulator (FO-PIE) (ii) fractional order positive inductor emulator (FO-PIE) (iii) integer order negative inductance emulator (IO-NIE) and (iv) integer order positive inductor emulator (IO-PIE). The proposed unified IE is designed around a single VDTA and a grounded fractional capacitor (FC) or capacitor only. Non-ideal mathematical formulations of the proposed IE are carried out to enumerate the effect of non-idealities associated with VDTA. The functionality of proposed structure is validated through Virtuoso from Cadence tool suite using 180 nm generic process design kit (gpdk) CMOS technology parameters. Power supplies of ± 0. 7 V are used for VDTA simulation. The continued fraction expansion (CFE)-based rational approximation is used for FC implementation which is realized using RC ladder network truncated to 12th order. Fractional negative and positive inductances of value 78.13 Ω / s 0. 3 , 23.44 Ω / s 0. 5 and 0.78 Ω / s 0. 7 are realized and simulated. The topology is also tested for 1 mH positive and negative integer order inductances. The simulation results corroborate with theoretical propositions. The applicability of the proposed structure is justified through two application examples namely parasitic fractional order inductance cancellation and fractional order high pass filter. [ABSTRACT FROM AUTHOR]

Background: Remifentanil and sufentanil are potent short-acting synthetic opioid analgesics. The administration of remifentanil has been associated with the incidence of opioid-induced hyperalgesia. Opioid-induced hyperalgesia may be alleviated when opioids, such as morphine, are switched to sufentanil. Therefore, this retrospective observational study aimed to compare the effects of remifentanil and sufentanil on postoperative pain in patients undergoing robotic gynecological surgery. Methods: We retrospectively analyzed the electronic medical records of patients who underwent elective robotic gynecological surgery between January 2016 and February 2021. The patients were classified into sufentanil (n = 159) or remifentanil (n = 359) groups according to the opioids administered continuously during anesthesia. The primary outcome assessed in this study was the postoperative pain score measured using the numeric rating scale (NRS). The secondary outcomes assessed included the recovery time (from discontinuation of opioid infusion to extubation) and frequency of rescue analgesic administration in the post-anesthesia care unit (PACU). Results: The recovery time did not differ significantly between the two groups. The NRS score for pain (median [1Q, 3Q]) in the PACU was significantly lower in the sufentanil group than in the remifentanil group (2 [2, 3] vs. 4 [3, 7], P < 0.001). The frequency of rescue analgesic administration in the PACU was 6.3% and 35.4% in the sufentanil and remifentanil groups, respectively (P < 0.001). Conclusions: Sufentanil, as an adjunct to sevoflurane anesthesia is more advantageous than remifentanil in terms of postoperative pain control during robotic gynecological surgery. [ABSTRACT FROM AUTHOR]

The use of fractional-order (FO) calculus for the solution of different problems in many fields has increased recently. However, the usage of FO system models in practice brings some difficulties. The FO operator, fractance device, is usually realized via several integer-order approximation methods, which have pros and cons in the aspect of operation frequency, time response and stability region. These methods may not meet all performance expectations. In this regard, author proposes an efficient hybrid integer-order approximation method for FO derivative operator without causing any additional difficulty in realization. The proposed method combines Matsuda and modified stability boundary locus (M-SBL) approximation methods. The advantage of each method is combined in a single hybrid function by considering root mean square error (RMSE) rates for step response. The performance of hybrid transfer function is analyzed in comparison with Matsuda, Oustaloup, continued fraction expansion (CFE) and M-SBL transfer functions for both frequency and time response. Analog realization of the proposed model is performed experimentally via partial fraction expansion method. Analog design is verified via both Multisim simulations and experimental results. The improvements due to the hybrid behavior and the consistency of experimental results with theoretical and simulation results demonstrate the practicality and usefulness of the hybrid model. [ABSTRACT FROM AUTHOR]

One of the central problems in control theory is related to the design of controllers for the improvement of system performance. The aim of this paper is to design an efficient digital fractional-order proportional-integral-derivative (FO-PID) controller for the speed control of buck converter fed permanent magnet DC (PMDC) motor. Speed control is achieved by a pulse width modulated control. The FO-PID controller parameters (gain and order) are obtained by using the ant colony optimization (ACO) technique. The effectiveness of the proposed control scheme is simulated and verified using MATLAB/Simulink results. The performance comparison shows that the speed control of buck converter fed PMDC motor is improved with proposed FO-PID controller than that of integer-order PID controller. [ABSTRACT FROM AUTHOR]

The main purpose of the present paper is to establish an alternative approach to compute the H2-norm for a fractional-order transfer function of the first kind based on Caputo fractional derivative. The key idea behind this new approach is the use of the concept of the parahermitian transfer matrices and the state-space realization. Numerical examples are presented to illustrate the new approach. [ABSTRACT FROM AUTHOR]

In this paper, a new optimal reduced order fractionalized PID (ROFPID) controller based on the Harris Hawks Optimization Algorithm (HHOA) is proposed for aircraft pitch angle control. Statistical tests, analysis of the index of performance, and disturbance rejection, as well as transient and frequency responses, were all used to validate the effectiveness of the proposed approach. The performance of the proposed HHOA‐ROFPID and HHOA‐ROFPID controllers with Oustaloup and Matsuda approximations was then compared not only to the PID controller tuned by the original HHO algorithm but also to other controllers tuned by cutting‐edge meta‐heuristic algorithms such as the atom search optimization algorithm (ASOA), Salp Swarm Algorithm (SSA), sine‐cosine algorithm (SCA), and Grey wolf optimization algorithm (GOA). Simulation results show that the proposed controller with the Matsuda approximation provides better and more robust performance compared to the proposed controller with the Oustaloup approximation and other existing controllers in terms of percentage overshoot, settling time, rise time, and disturbance rejection. [ABSTRACT FROM AUTHOR]

Fuel cells are essential components of renewable energy sources. There are many industrial applications related to them. One of the sample applications is electrical power compensation systems (EPCS). EPCS, as one of the essential parts of electrical installations, are used to eliminate reactive power. In this study, the effective control of a static compensation system developed for fuel cell power-generation plants is studied to eliminate the reactive power caused by the loads. The static compensator is a five-level inverter consisting of 24 IGBTs. Here, advanced and hybrid controllers are used and tested together. In the study, fractional-order proportional–integral–derivative controller-based model predictive controller (MPC), tilt-integral-derivative controller-based MPC controller, and hybrid fractional-order proportional-tilt-integral-derivative-based MPC (FOPTID-MPC) controller are used, and their efficiencies compared in terms of transient response characteristics and an error-based performance function. In addition, the parameter adjustments of the controllers are made using the Pathfinder Optimization Algorithm. The effectiveness of the proposed FOPTID-MPC controller scheme is shown. [ABSTRACT FROM AUTHOR]

Background: Total intravenous anaesthesia (TIVA) is a ideal substitute to inhalation anaesthesia because of hemodynamic complications. TIVA with suitable combination of anaesthetic drugs will have good post-operative results. Method: 60 patients aged between 18 to 65 years undergoing laparoscopic cholecystectomies were studied. Sixty patients classified in three groups, 20 patients in each group. GroupsS1 and S2 received propofol with sufentanil added at 1µgml and 2 µg ml concentration respectively while group P received propofol without sufentanil. Additional sufentanil boluses (10 µg) were when there is an increase in the hemodynamic parameters, recovery times, and post-operation analgesia g were compared in all three groups of patients. Results: Hemodynamic parameters (HR, SBP, DBP) were not significantly different in all three groups. Fewer S2 patients required additional sufentanil boluses to maintain proper hemodynamic status. S2 group had better postoperative analgesia (p<0.001) but prolonged recovery time as compared to other two groups. Conclusion: Sufentanil mixed with propofol provides better hemodynamic stability in laparoscopic cholecystectomies where more chances of pneumothoraxdue to fluctuations in hemodynamic parameters which may lead to morbidity and mortality [ABSTRACT FROM AUTHOR]

This paper concentrates on computing the stabilizing region of fractional‐order proportional integral derivative (FOPID) controllers for interval delayed fractional‐order plants. An interval delayed fractional‐order plant is defined as a fractional‐order transfer function with a time delay whose denominator and numerator coefficients are all uncertain and lie in specified intervals. In the present study, first, a theorem is proven to analyze the robust stability of the given closed‐loop. Then, a method is proposed to solve the problem of robustly stabilizing interval delayed fractional‐order plants by using FOPID controllers. Moreover, two auxiliary functions are presented to fulfill the additional specifications of design, ensuring better performance of the controlled system with respect to the disturbance and noise. Finally, two examples are provided to illustrate the design procedure. [ABSTRACT FROM AUTHOR]

In light of the COVID-19 pandemic, many patients have suffered from Acute Respiratory Distress Syndrome (ARDS) in Intensive Care Units (ICUs) around the world. In the medical field, it is known that the so-called artificial ventilation device, which has become the mainstay of treatment of such syndrome, decreases mortality in critically ill COVID-19 patients. Due to the high reliability of this device, there is an emergency need to follow up the progress made on designing a robust controller for improving its performance. From this perspective, this work introduces different control design schemes for obtaining an optimal Fractional-order PID controller (or simply PIρDμ-controller) of the Artificial Ventilation (AV) system through two optimization algorithms: the Bacteria Foraging Optimization (BFO) and the Particle Swarm Optimization (PSO) algorithms. The realization of the controller is accomplished using four approximations: Oustaloup's approximation, the Continued Fractional Expansion (CFE) approximation and the 1st- and 2nd-order El-Khazali approximations. The validation of the controller design and the AV system behavior are verified via numerical simulation in order to demonstrate the effectiveness and the potency of all proposed schemes. [ABSTRACT FROM AUTHOR]

Cucullanus tunisiensissp. nov., (Nematoda: Cucullanidae), collected from the intestine of the white grouper Epinephelus aeneus from waters off the coast of Tunisia is described based on light and scanning electron microscopic observations. The new species is characterized by the presence of lateral alae, ventral sucker, long unequal spicules (left spicule 2474-2789 μm long, right spicule 2357-2518 μm long). This is the sixth nominal species of the genus Cucullanus Müller, 1777 and the first representative of this genus infecting fishes of Serranidae family reported from Tunisian waters. [ABSTRACT FROM AUTHOR]

The generation of energy from renewable sources is dependent mostly on weather conditions because of which instabilities in the hybrid microgrid system may arise. To tackle the same in such a system, coordinated frequency and voltage control with appropriate control strategy have been investigated in this work considering a single area independent hybrid system. A combined solar gas turbine, solar chimney, and biodiesel-operated generator along with hybrid electric vehicles and refrigerators as the thermostatic load are used to model the hybrid system. Constraints of the proposed cascaded PI-TID controller are finely tuned with the recently developed DBOA. Coordinated frequency and voltage control of a combined solar gas turbine-solar chimney with thermostatic loads in an isolated hybrid microgrid system have not been reported earlier. Furthermore, the application of DBOA to tune a cascaded PI-TID controller for coordinated control of voltage and frequency is a novel approach. Extensive simulation studies of the model is carried out to obtain the dynamic response by considering various uncertain conditions. Values of maximum overshoot (0.002194), undershoot (0.006042), and setting time (1.781sec) of frequency deviation and peak overshoot (0.002296), undershoot (0.004511), and setting time (1.709 sec) of voltage deviation proved the effectiveness of the proposed system. [ABSTRACT FROM AUTHOR]

This paper proposes a compound data-driven control method to solve the problems of low damping resonance, different dynamic properties, and hysteresis in the large-range compliant micropositioning stage driven by a Maxwell reluctance actuator. First, in order to verify the proposed control algorithm, a reluctance-actuated, XY compliant micropositioning stage is constructed according to the principle of operation of a reluctance actuator. Second, in order to eliminate the influence of complex dynamics on the controller design, a fractional order proportional-integral feedback controller is designed using a data iterative feedback turning algorithm. Third, the finite impulse response feedforward filter is optimized using experimental data, and the on-line inverse estimation of the system frequency response function and its iterative feedforward compensation are carried out to further eliminate the influence of light damping resonance. Finally, the proposed control method is used for tracking the experiment and compared with other methods. The experimental results show that the proposed control method can better meet the requirements of high precision, fast speed, and strong anti-interference ability for large stroke micro/nanopositioning and tracking. [ABSTRACT FROM AUTHOR]

Any alternating electric power supply is always characterized by three reference quantities, which are voltage, electric power and frequency. The generators of power stations are synchronous machines. The present work is based on the modelling of the synchronous machine for a study of the stability of the electricity transmission network. The example considered is a thermal power station of the national network. i.e., Algiers port power station. We have developed a computer program based on MATLAB to simulate the calculations of our multi-variable system. The study presented in this article examines the static stability of a thermal power plant. To make this study a reality, it is necessary to model the synchronous machine. We present the three models of the synchronous machine by emphasizing the role of the shock absorbers and the smoothness of the model with three windings. This work is supported by a spectral analysis based on the eigenvalues of the system. [ABSTRACT FROM AUTHOR]

Electric vehicle (EV) has been widely used in our life, one of the key technologies is the batteries, power accumulator battery test system (PABTS), which is initiated for evaluating the performance of the EV batteries, has been used in many battery-manufacture companies. The parallel operation of the PABTS forms a dc-microgrid, owing to the low inertia of the dc-link capacitance, the charging and discharging tests of the batteries can easily cause dc-bus voltage fluctuations, which may jeopardize the system stability. To increase the system inertia and achieve good system stability, a fractional-order model-predictive-control (FOMPC) and fractional-order virtual-inertia-control (FOVIC) strategy (namely, FOMPC-FOVIC method) is proposed for the bidirectional grid-connected converter. First, the fractional-order virtual inertial link is used to replace the integral-order virtual inertial link, which significantly improves the system stability. Second, combined with fractional-order model-predictive-control, virtual dc current compensation is proposed to further suppress the dc-bus voltage fluctuations. Finally, the fractional-order discrete state-space equation of the virtual inertial link is derived, and the cost function design and its optimal solution are elaborated. To demonstrate the effectiveness of the proposed FOMPC-FOVIC scheme, experimental results indicate that the proposed method is superior to the existing methods in terms of inertial support and dc-bus voltage regulation. [ABSTRACT FROM AUTHOR]

This article proposes a fractional-order intelligent fault-tolerant synchronization tracking control (FO-I-FTSTC) scheme for multiple unmanned airships (UAs) against actuator faults. Within the developed control architecture, fixed-time prescribed performance functions (PPFs) are first designed to transform the synchronization tracking errors into a new set of error variables, such that the original errors are strictly confined within the prescribed bounds. Then, fractional calculus and sliding mode surface are sequentially introduced to construct the FO errors. Moreover, to handle the unknown terms and bias faults in the FO sliding-mode error dynamics, fuzzy neural networks with recurrent loops are artfully constructed to act as the intelligent learning units. Furthermore, the norm of the loss-of-effectiveness fault factors is introduced for each UA to reduce the number of adaptive parameters. The distinct feature of the proposed method is that the FO-I-FTSTC performance is significantly enhanced by integrating recurrent fuzzy neural networks, fractional calculus, and fixed-time PPFs into a unified framework, leading to a high-precision control scheme. It is shown by Lyapunov analysis that all UAs can track their desired references in a synchronized manner, and the synchronization tracking errors are bounded and strictly confined within the prescribed error bounds. Comparative hardware-in-the-loop experiments are presented to show the effectiveness of the proposed FO-I-FTSTC scheme. [ABSTRACT FROM AUTHOR]

A novel fuzzy adaptive finite‐time controller is designed for synchronization and control of the Duffing–Holmes and the gyroscope systems in the presence of uncertainty and external disturbance. The fractional‐order fast nonsingular terminal sliding mode manifold is used to ensure the finite‐time control, speed up the convergence rate, and address the singularity problem of the conventional terminal sliding mode controller. Also, the novel control law successfully reduces the chattering phenomenon. Adaptive biased type‐II fuzzy inference system is used to determine the optimal values of the switching control term. The adaptation rules of the novel fuzzy inference system are achieved based on Lyapunov stability theorem. Finally, by using numerical simulations, the effectiveness and superiority of the proposed control scheme are verified against some other methods. [ABSTRACT FROM AUTHOR]

This research presents a fractional order (FO) controller for frequency control in microgrid. Four intelligent methodologies, namely, Grasshopper optimization algorithm (GOA), Gravitational search algorithm (GSA), Genetic algorithm (GA), and Particle swarm optimization (PSO), are used for optimization-based tuning of FO controller. The proposed microgrid consists of wind turbine, solar photo voltaic system, aqua electrolyser, flywheel, ultra-capacitor, battery storage system, diesel engine, and fuel cell. GOA is employed to tune the parameters of the controllers. Application of GOA-based two-/multi-stage fractional order PID controller i.e., FOPID-(1 + PI) controller in frequency control for microgrid is a novel work. GOA-optimized FOPID-(1 + PI) controller unveils best results over the conventional PID/FOPID controller in terms of settling time, peak undershoot/overshoot, and performance index. Examination of dynamic responses for abrupt changes in load request divulges the pre-eminence of the proposed controller strategy with others. The robustness study implies that GOA-optimized fractional controller operates superbly and robustly under nonlinearities and perturbation in system parameters. In order to demonstrate the ascendancy of GOA, its results in terms of statistical parameters and performance index are compared with the results of GA, PSO, and GSA. [ABSTRACT FROM AUTHOR]

This article deals with the control chassis dynamics of a light electric vehicle. In the frame of Global Chassis Control, it proposes a hierarchical control approach focuses on compensating the chassis dynamics against driver disturbances. It is based on a supervisory structure consists of two main levels, a global controller for regulating chassis variables and a local controller to each suspension system. Both controllers are designed using a fractional-order robust controller, namely CRONE controller, to provide an optimized solution for the performance-robustness tradeoff. The main objective is to improve ride comfort for passengers while respecting road holding and handling criteria. In contrast to other studies, random road disturbances are considered to investigate the limits of the proposed approach. Analysis in frequency and time domain has been done to evaluate the performance and robustness of the designed controller. Simulation results based on a full nonlinear 14 degree of freedom vehicle model show that the proposed strategy can effectively improve the ride quality in the field of interest where a significant performance in driver disturbance rejection is reported. [ABSTRACT FROM AUTHOR]

Five new structures of linear fractional-order voltage-controlled oscillators (FO-VCOs) utilizing only Multiplication-Mode Current Conveyors (MMCCs) and canonic numbers of all grounded passive elements (AGPEs) are presented in this paper. The derivation procedure has been detailed along with the relevant nonideal analysis. The work also presents three fractional-order cases of the oscillators and brings out the effects of port nonidealities and port parasitics on the performance of presented FO-VCOs. The workability of all the five new FO-VCOs has been validated on PSPICE utilizing library files of AD844 and AD835 for realizing MMCC employed in the FO-VCOs. For all the three special fractional-order cases, the simulation results have been tabulated along with relevant MATLAB plots that facilitate comparison among oscillation parameters and the fractional order. The harmonic distortion figures have been found out by Fourier analysis. Experimental workability of a VCO, employing MMCC realized with AD835 and AD844 of our investigation is included to support hardware functionality. [ABSTRACT FROM AUTHOR]

Herein, the fractional derivative is firstly proposed to describe the constitutive relationship of a fluid inerter, and a dynamic model of a vibration isolation system (VIS) with both a fractional-order inerter and damper is established. The effects of the inerter parameters on the displacement transmissibility are analyzed; the results indicate that the fractional constitutive model can express the inertia and damping effects simultaneously, and the ratio between them can be changed by adjusting the derivative order. Furthermore, semi-analytical calculation methods of fractional critical damping, and optimal fractional critical damping and corresponding derivative order are proposed and verified through three examples. [ABSTRACT FROM AUTHOR]

In this work, an attempt has been made to implement a fractional based internal model control (IMC) for automatic generation control (AGC) of power system. In general power system, models are complex and having higher orders, as a result design procedure of IMC controller for AGC becomes complicated one. In this work, model order reduction (MOR) techniques are introduced to reduce effort in designing controller for such a complex system. These techniques can capture dynamics of higher order power systems with lower order models without loosing inherent properties of system. In this paper, Nyquist-based model reduction technique is employed for integer order model compression. A simple structure fractional order filter in cascade with fractional order proportional integral derivative (FOPID-FOF) controller based on the IMC theory is developed for obtained lower order models to solve load frequency control (LFC) problem. The distinguished feature is the less number of tuning parameters for the design of fractional controller. The resultant controller is implemented for the single area power system in MATLAB environment. The simulation results are compared to show the effectiveness of the proposed method. Also, the proposed method is applied to two area PV-Reheated power system and three area non-reheated power system. [ABSTRACT FROM AUTHOR]

This paper presents the continuous-time fractional linear systems and their main properties. Two particular classes of models are introduced: the fractional autoregressive-moving average type and the tempered linear system. For both classes, the computations of the impulse response, transfer function, and frequency response are discussed. It is shown that such systems can have integer and fractional components. From the integer component we deduce the stability. The fractional order component is always stable. The initial-condition problem is analyzed and it is verified that it depends on the structure of the system. For a correct definition and backward compatibility with classic systems, suitable fractional derivatives are also introduced. The Grünwald-Letnikov and Liouville derivatives, as well as the corresponding tempered versions, are formulated. [ABSTRACT FROM AUTHOR]

An intelligent model of the incremental capacity (IC) curve of an automotive lithium-ferrophosphate battery is presented. The relative heights of the two major peaks of the IC curve can be acquired from high-current discharges, thus enabling the state of health estimation of the battery while the vehicle is being operated and in certain cases, aging mechanisms can be suggested. Our model has been validated using a large dataset (number of batteries) representing different degradation scenarios, obtained from a recently available open-source database. [ABSTRACT FROM AUTHOR]

This article focuses on the robust D-stabilization analysis of fractional-order control systems where each of the system and the controller may be of fractional order. The coefficients of the system are considered as complex linear functions of interval uncertain parameters, so this article deals with fractional-order polytopic systems. First, a necessary and sufficient condition is introduced for the robust D-stabilization of the closed-loop control system based on the zero exclusion condition and the value set concept. Then, the geometric pattern of the value set of the characteristic polynomial is obtained analytically using the exposed vertices. Second, a function is presented to check the introduced condition. Third, the transition points, at which the exposed vertices of the value set may change, are derived to reduce the computational burthen. Fourth, a new function is provided to determine the D-stability robustness radius (margin) of these control systems, that is, determining bounds on the uncertain parameters such that the control system remains D-stable. The achieved results are applicable to systems of incommensurate order and consequently of commensurate order. Finally, numerical simulations and practical experiments based on a three-degrees-of-freedom flight simulator turn table are conducted to illustrate the achieved results. [ABSTRACT FROM AUTHOR]

In this article, we deal with the development of a fractional-order notch filter (FONF) for a grid-connected solar photovoltaic (PV) system. The developed FONF control approach is used to estimate fundamental active constituents from the distorted load currents, and hence, gating pulses for operating voltage source converter (VSC) are used in the PV system. This control approach for the grid-connected solar PV system is designed to achieve several purposes, such as feeding active power demand of the load/grid and countercurrent-related power quality issues at the common connecting point. The power quality issues taken into consideration are harmonics distortion, reactive power burden on the system, and unbalancing of connected loads. The FONF-based control proposes a modified structure of an integer-order notch filter. The integer-order filters have a limitation due to the fixed integrator and differentiator terms. In FONF, the power of integrator used in a notch filter can be modified according to the application required for obtaining the accurate response of the system. A prototype of the grid-connected solar PV system is developed in the laboratory using IGBTs based VSC and dSPACE MicroLabBox (DS-1202) to demonstrate the behavior of the FONF-based control. Simulation and experimental results are obtained for steady-state and unbalanced loads with variation in the solar irradiance. The harmonic distortions in the system are observed as per the IEEE-519 standard. [ABSTRACT FROM AUTHOR]

This article presents a novel Whale Optimization Algorithm (WOA) approach for optimal tuning of Fractional-Order Proportional Integral and integral-order Controller (FOPIλ) is used to solar Photo-Voltaic (PV) fed sensorless speed control of Permanent Magnet Brushless DC (PMBLDC) motor under the various operating condition such as (i) speed change by set speed command signal, (ii) solar PV output voltage variations, (iii) varying load conditions, (iv) integrated conditions, and (v) controller parameters uncertainty. The PMBLDC motor is remarkably robust speed control against the uncertainties, Solar PV output power fluctuation, external load disturbances, the nonlinearity characteristics, and poor controllability. To overcome this above limitation, optimization algorithms are proposed namely Bat Algorithm (BA), Grey Wolf Optimization (GWO), and WOA optimized FOPIλ controllers. To develop a MATLAB 2019a/Simulink model of FOPIλ controller for Solar PV-fed sensorless speed control of PMBLDC motor using BA, GWO, and WOA and corresponding numerical simulation results are carried out under various working conditions. It shows the effectiveness of the proposed controllers is completely verified by comparing the above three intelligent optimization techniques. It is evident that out of these three intelligent controllers, the WOA-optimized FOPIλ controller for solar PV-fed sensorless speed control of PMBLDC motor gives enhanced performance by minimizing the time domain parameters, performance indices error, convergence time, control efforts, cost function, mean, and standard deviation. [ABSTRACT FROM AUTHOR]

A detailed analysis of the recent developments on the realization of fractance device is presented. A fractance device which is used to exhibit fractional order impedance properties finds applications in many branches of science and engineering. Realization of fractance device is a challenging job for the people working in this area. A term fractional order element, constant phase element, fractor, fractance, fractional order differintegrator, fractional order differentiator can be used interchangeably. In general, a fractance device can be realized in two ways. One is using rational approximations and the other is using capacitor physical realization principle. In this paper, an attempt is made to summarize the recent developments on the realization of fractance device. The various mathematical approximations are studied and a comparative analysis is also performed using MATLAB. Fourth order approximation is selected for the realization. The passive and active networks synthesized are simulated using TINA software. Various physical realizations of fractance device, their advantages and disadvantages are mentioned. Experimental results coincide with simulated results. [ABSTRACT FROM AUTHOR]

In this paper, fractional-order chaotic systems in an analog-based platform are realized using field programmable analog arrays (FPAA) hardware. With the help of this work, we aim to increase the complexity of chaotic systems. Approximated transfer functions in frequency domain are obtained by analyzing different values of fractional-order integrator with the Charef approximation method. In this study, fractional-order numerical calculation of Rssler and Sprott type-H chaotic systems is carried out. MATLAB Simulink model for chaotic systems that satisfy the conditions of chaos in the boundaries of fractional order value is schematically presented. Moreover, CAM designs and analysis that facilitate the realization of fractional-order transfer functions in FPAA platforms are introduced. The analog-based FPAA experimental and numerical outcomes for fractional order chaotic systems are demonstrated. The comparison of the results obtained in the numerical analysis and simulation study with the experimental results is given. This study confirms that the unpredictability of the chaos carrier signals realized by digital-based can be increased with analog-based FPAA hardware and fractional-order structures so as to provide safer transfer of information signals. [ABSTRACT FROM AUTHOR]

This study employs the Caputo–Fabrizio and Atangana–Baleanu fractional derivatives to determine the impedance and admittance model of fractional capacitor and inductor. The analog implementation circuits are proposed aiming at fractional-order electric elements based on these two derivatives, which can be widely used in a variety of electrical systems using new fractional operators. Constant phase capacitor and inductor are approximated by the Oustaloup algorithm and the recursive net-grid-type analog circuit, respectively. Based on that, approximation circuits of fractional electric components under Caputo–Fabrizio and Atangana–Baleanu definitions are given. For the purpose of judging whether the implementation topology of fractional-order capacitor and inductor is accurate, taking fractional RC and RL circuit defined by Caputo, Caputo–Fabrizio and Atangana–Baleanu derivatives as examples, the comparison of numerical and circuit simulations is carried out. The correctness of the analog implementation circuits using the Caputo–Fabrizio and Atangana–Baleanu definitions is verified. Fractional-order RC charging circuit experiments based on Caputo, Caputo–Fabrizio and Atangana–Baleanu derivatives are taken as examples. Several experiments with different fractional-order and circuit parameters are carried out. The validity of the implementation methods is ulteriorly proved with experiment data. [ABSTRACT FROM AUTHOR]

In this study, a new sinusoidal fractional oscillator circuit in which the fractional low-pass filter and fractional differentiator form a closed loop has been introduced. The single series R − C pair and Valsa method have been used to imitate the fractional-order capacitor. Two different sinusoidal signals with different phases are available at output ports. An integer version of the proposed oscillator is not possible, only the fractional version is valid, that is a noticeable feature. The introduced circuit has been simulated by employing SPICE software. The proposed fractional oscillator is also verified by implementing circuit with AD817ANs and passive components, experimentally. [ABSTRACT FROM AUTHOR]

For battery equivalent circuit model parameter identification, the fractional-order modeling and the bionic algorithm are two excellent techniques. The former can describe the impedance characteristics of batteries accurately, while the latter has natural advantages in solving some nonlinear problems. However, the high computational cost limits their application. In this article, a parameter-identification method for a battery fractional-order model based on the coevolutionary particle swarm optimization (CPSO) is proposed. In this algorithm, a large number of optimization calculations are dispersed between the adjacent sampling times in the form of evolutionary steps by CPSO, so the algorithm can run in real time with the sampling process. In addition, the simplified fractional approximation further reduces the computational cost. By conducting tests under various algorithm conditions, we evaluate the main factors affecting the algorithm performance in detail. Our results show that compared with the integer-order model, the fractional-order model can track the optimal value more effectively in a wider optimization space, CPSO can track the time-varying battery parameters in real time by continuous evolution, and computational costs can be effectively reduced by using a fixed-order fractional-order model and appropriately compressing the length of the historical data required for fractional-order computation. [ABSTRACT FROM AUTHOR]

The main goal of anesthesiology is to achieve the best level of analgesia and a fast recovery of consciousness following anesthesia. The preservation of spontaneous breathing during general anesthesia with anesthetic gases is practiced by many anesthetists. However, very few studies have dealt with these positive properties of volatile anesthetics such as sevoflurane or desflurane. Remifentanil is a very short half-life opiate that combines sufficient intra-operative analgesia with a fast post-operative recovery time. We tested the hypothesis that spontaneous breathing can reduce overdosing with remifentanil during desflurane anesthesia. In this prospective, single center, multiple anesthetist study, 30 patients were randomized into two groups (volume-controlled ventilation mode and spontaneous breathing). The spontaneous breathing group showed a significantly lower post-operative pain level than the volume-controlled ventilation mode group. Furthermore, less remifentanil as well as less piritramide was needed in the spontaneous breathing group compared with volume-controlled ventilation mode. It was possible to achieve spontaneous breathing in all patients with 0.6 minimum alveolar concentration desflurane, in order to control the remifentanil rate and prevent an overdose. All spontaneous breathing patients had low intra- and post-operative pain levels and the need for analgesics was equal to or lower than that in the volume-controlled ventilation mode group. By reducing the intra-operative amount of opiates, both the post-operative pain and the amount of post-operative analgesia required can be reduced. A balanced anesthesia with spontaneous intra-operative breathing is needed to determine the required amount of opiates. This study was approved by the Ethic Committee of the Ruhr-University of Bochum (approval No. 2435) in September, 2004. [ABSTRACT FROM AUTHOR]

The design of non‐integer order controllers and tuning of its fractional parameters have attracted the research community of science and engineering in previous years. However, few attempts already have been done by the researchers to present the excellent results for some limited cases of models using fractional controllers; still, many physical world problems are untouched and waiting to be discovered. The big obstacle which impounds the adaptation of non‐integer controllers is the complexity in the tuning rules for physical systems. The objective of this article is to present a novel graphical tuning approach of mono and dual degree fractional controllers to fulfill the five different design requirements such as iso‐damping, gain crossover frequency, sensitivity, phase margin, and steady‐state error cancellation. To demonstrate the effectiveness of the suggested tuning technique, two test bench setups, rotary inverted pendulum and magnetic levitation system, have been taken as a case study. The experimental results are given to validate the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This study attempts to maintain the terminal voltage level of an automatic voltage regulator (AVR) and control the speed of a direct current (DC) motor using a fractional order proportional integral derivative (FOPID) controller. The best parameters of the controller have been adjusted using a novel meta-heuristic algorithm called opposition-based hybrid slime mold with simulated annealing algorithm. The proposed algorithm aims to improve the original slime mold algorithm in terms of exploitation and exploration using simulated annealing and opposition-based learning, respectively. A time domain objective function was adopted as performance index to design the FOPID-based AVR and DC motor systems. The initial performance evaluation was carried out using unimodal and multimodal benchmark functions. The results confirmed the superior exploration and exploitation capabilities of the developed algorithm compared to the other state-of-the-art optimization algorithms. The performance of the proposed algorithm has also been assessed through statistical tests, time domain and frequency domain simulations along with robustness and disturbance rejection analyses for both DC motor and AVR systems. The proposed algorithm has shown superior capabilities for the respective systems compared to the other state-of-the-art optimization algorithms used for the same purpose. [ABSTRACT FROM AUTHOR]

Copyright of Automatisierungstechnik is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this paper is to determine analytically the resonance limits for second kind commensurate fractional systems in terms of the pseudo damping factor ξ and the commensurate order v and in addition specify the different resonance regions. In the literature, these limits and regions have never been discussed mathematically, they are determined numerically. Second kind commensurate fractional systems are resonant if the equation : Ω3v + 3ξcos(vπ/2)Ω2v + (2ξ2 + cos(vπ))Ωv + ξcos(vπ/2) = 0, obtained by setting the first derivative of the amplitude-frequency response equal to zero, has at last one strictly positive root. As in the conventional case, resonance limits correspond to zero discriminant of the last equation. This discriminant is a cubic equation in ξ2 whose coefficients change depending on v. To resolve this equation, the tangent trigonometric solving method is used and the relationship between ξ and v is established, which represents the resonance limits expression. To search resonance regions, a mathematical study is conducted on the first equation to find the positive roots number for each (v, ξ) combination. Compared to works already achieved, a new region appeared in the region of single resonant frequency with an anti-resonant one. The results are tested through numerical examples and applied to a fractional filter. [ABSTRACT FROM AUTHOR]

This brief proposes a discrete-time fractional-order differentiator based on the super-twisting algorithm for second-order systems. The differentiator achieves higher performance with respect to the classical ones of integer order in terms of convergence time and robustness. It relaxes the classical boundedness condition required to be satisfied by the second-order derivatives of the functions in conventional differentiators. The numerical integration is performed by an implicit Euler discretization technique based on the Fractional Adams-Moulton method, which significantly suppresses the chattering. The significance of the proposed differentiator is demonstrated through a simulation example, comparing with the classical ones. [ABSTRACT FROM AUTHOR]

This article presents our recent work towards development of a controller for the new class of modernized excavators. There is an increasing demand to develop autonomous earth-moving machines that are: more efficient than the conventional ones and capable of operating with minimal supervision by operators. A fractional-order pro-portional-integral-derivative (FOPID) control is applied to a newly designed electro-hydrostatic actuator (EHA) circuit for these machines. We further employ the Oustaloup recursive method for which the parameters of the controller are chosen based on the modified Nelder-Mead optimization algorithm. Our experimental results indicate that the proposed controller is capable of controlling the speed of the link with a negligible error. This work paves the road for development of autonomous, energy efficient, off-road mobile machines. [ABSTRACT FROM AUTHOR]

Copyright of Revista Mexicana de Biodiversidad is the property of Universidad Nacional Autonoma de Mexico, Instituto de Biologia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to deal with some difficult problems in fractional-order systems, like high computational load of fractional-order operator, fractional-order transfer function is commonly approximated by an integer order model. However, the dimension of this model increases with its accuracy, which can make the design of a controller more difficult. In this paper, a new approach for modelling of fractional-order systems is investigated. Exploiting the multimodel technique, the suggested method replaces the unique fractional-order model by a set of simpler integer order models. The determination of the different models is based on an approximation of the fractionalorder derivative operator sα. Then the global model is obtained through a fusion of the simple models weighted by their respective relevance degrees calculated by optimizing a constrained least squares problem. The resulting final model can represent adequately the fractional-order systems both in time and in frequency domains. Simulations and comparative studies carried out on academic examples indicate the interest, the clarity and the improvement in accuracy in both time and frequency domains of the proposed modelling method, compared to modelling by a single model based on the approximation of Oustaloup. [ABSTRACT FROM AUTHOR]

The paper presents the theoretical foundation and practical implementation aspects of Fractional Order Controllers (FOCs) for power system applications. With this aim, the paper provides a comprehensive mathematical background on the stability analysis of dynamic systems with inclusion of fractional order derivatives and discusses their software implementation based on the Oustaloup's Recursive Approximation (ORA) method. Then the paper illustrates a variety of examples of ORA-based FOCs, namely, automatic generation control of synchronous machines; frequency control of a converter-interfaced energy storage system; and voltage control through a static synchronous compensator. The WSCC 9-bus test system and a realistic 1,479-bus model of the Irish transmission system are employed to test and compare the examined FOCs with their integer-order versions. [ABSTRACT FROM AUTHOR]