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The purpose of the study is to highlight the creation and development of machine and horse stations in the MASSR. The end of the 20s of the last century marks the actual beginning of a complex process of collectiv- ization of the agrarian sector in the USSR. The creation of the machine and horse stations on the territory of the Moldavian Autonomous Soviet Socialist Republic contributed to the emergence of bases capable of supplying, if necessary (especially in the spring, when sowing was carried out), agricultural machinery and draft power. At the same time, such stations were used as a propaganda tool in favor of the nationalization of property. Ultimately, this form of organization of the collective mode of production did not give the expected results, and the main reason for the failure was poor management of human resources. Familiarization with archival documents showed that this method of using horses in agricultural work turned out to be ineffective. The failure of the machine and horse stations organization was one of the first evidence that personal material interest prevails over the collective one. [ABSTRACT FROM AUTHOR]

One of the maximum popular renewable electricity assets is photovoltaics. Grid-connected photovoltaic structures are designed to generate as a lot strength as possible. Photovoltaic systems have nonlinear traits imposed with the aid of environmental factors consisting of radiation and temperature, making it hard to operate at the most power factor. It may additionally be tough to extract the maximum amount of electricity due to the formation of nearby maxima because of other factors which include shading or degradation. There are several MPPT algorithms and approaches that may be used for this. Publications with comparative analyses have also been released. However, in most of these works, comparisons are based on simulations or literature review. From the simplest to the most complex MPPT methods, empirical validation remains important. The two simplest and most widely used MPPT techniques are the perturbation, open-loop, and incremental conductance algorithms. The three most challenging ones are sliding mode control, backstepping controller, and particle swarm optimization. Therefore, five MPPT algorithms are empirically studied in this paper. Under test settings, Matlab/Simulink was used to conduct experimental experiments. The findings demonstrate that under ordinary operating circumstances, the backstepping algorithm is the only one capable of finding the global MPP under the influence of local shadowing. [ABSTRACT FROM AUTHOR]

For proper functioning and stability of a power system, it is of utmost importance that the system frequency is kept within permitted operating limits using the Automatic Generation Control (AGC) else stability is compromised. This may lead to disruption of system operation and/or damage of the power grid equipment. The AGC system must be protected against false data injection (FDI) attacks as the information required by AGC is transmitted to the control centre by the means of communication links which are vulnerable against cyber-attacks. Hence, to overcome this issue a Generalized Extended State Observer (GESO) based resilient sliding mode compensator is developed in this paper. GESO is used for the purpose of detecting FDI attacks against the AGC system. In order to mitigate the effect of the FDI attack in the system, sliding mode compensator is utilised. It not only mitigates the effect of attacks but also allows the control centre to make its decision based on the uncompromised sensor signals instead of the compromised signals. The proposed method is subjected to a variety of FDI attacks and the simulation results confirm its competency to successfully detect, estimate and compensate for FDI attacks regardless of the effect of AGC nonlinearities. [ABSTRACT FROM AUTHOR]

The features of the local mean and fluctuational flow structure, carrier phase turbulence and the propagation of the dispersed phase in the bubbly and droplet-laden isothermal round polydispersed jets were numerically simulated. The dynamics of the polydispersed phase is predicted using the Eulerian–Eulerian two-fluid approach. Turbulence of the carrier phase is described using the second-moment closure while taking into account the presence of the dispersed phase. The numerical analysis was performed in a wide range of variation of dispersed phase diameter at the inlet and particle-to-fluid density ratio (from gas flow laden with water droplets to carrier fluid flow laden with gas bubbles). An increase in the concentration of air bubbles and their size leads to jet expansion (as compared to a single-phase jet up to 40%), which indicates an increase in the intensity of the process of turbulent mixing with the surrounding space. However, this makes the gas-droplet jet narrower (up to 15%) and with a longer range in comparison with a single-phase flow. The addition of finely dispersed liquid droplets to an air jet suppresses gas phase turbulence (up to 15%). In a bubbly jet, it is found that small bubbles (Stk < 0.1) accumulate near the jet axis in the initial cross-sections, while concentration of the large ones (Stk > 0.2) along the jet axis decreases rapidly. In the gas-droplet jet, the effect of dispersed phase accumulation is also observed in the initial cross-section, and then its concentration decreases gradually along the jet axis. For gas bubbles (Stk < 0.1), small turbulence attenuation (up to 6%) is shown. [ABSTRACT FROM AUTHOR]

Controlling the manipulators in a precise manner is a challenging task. To overcome this difficulty around the world, many researchers have developed various control algorithms but are not providing optimal results. To obtain the optimal results in the current research the authors designed a proportional, integral, and derivative (PID) controller, fuzzy logic controller (FLC), and sliding mode controller (SMC) for a 2-DOF manipulator. The concept of forward and inverse kinematics was initially solved after assigning the D-H parameters for each joint. The purpose of forward or direct kinematics is to obtain the position and orientation of the end effector. Further, the concept of inverse kinematics is used to estimate the joint angles. Later on, the Lagrange-Euler formulation was used to calculate the dynamics of the 2-DOF manipulator, which is required to estimate the torque required for each joint of the robotics arm. The main goal of this research problem is to optimize the angular error between the two successive events. Finally, the developed algorithm is compared with the existing algorithms such as PID and Fuzzy logic controller.

The 4-wheel independent drive (4WID) electric vehicle has better safety and stability. However, the multi-motor drive system would lead to an increased fault probability in the vehicle. In particular, the uncertainty of fault motors and parameter disturbances could lead to uncertainties in control. This study presents a fault-tolerant hierarchical control approach that utilizes an improved Model Predictive Control (MPC) to address the problem. The proposed method employs Sliding Mode Control (SMC) in the upper layer to generate the vehicle’s yaw moment, which could inhibit system parameter disturbance and improve the system’s robustness. Incorporating the fault matrix induced by motor malfunctions, the state-space equation of the vehicle is modified to establish a vehicle dynamics model under motor faults. In the lower layer, the torque reconstruction allocation strategy is designed to coordinate the four motors under the motor fault condition by the MPC rolling optimization online, which could reduce the impact of the motor fault uncertainty for fault-tolerant control. The multi-constraint conditions of MPC are set up according to the vehicle state parameters. To address the additional yaw moment caused by the MPC torque reconfiguration allocation control strategy, the torque transfer method is used as the input allocation for MPC. Finally, the proposed control strategy is verified by online simulation. The simulation outcomes demonstrate the effectiveness of the proposed hierarchical fault-tolerant control approach in achieving fault-tolerant control of the 4WID electric vehicle, with the improved MPC outperforming the conventional MPC in terms of performance.

Active Magnetic Bearing system (AMB) is a nonlinear mechatronic device utilized for levitating the rotating components of a machine without physical contact with the stationary parts. The nonlinearity properties pose a challenge for ensuring system stability. To achieve stable and optimal performance, controllers must be incorporated. A model of the proposed AMB has been derived and results a $2\times 2$ MIMO system. To simplify it, the model is linearized using Taylor series expansion technique. Simulation experiments have been conducted using MATLAB. In this paper, a neuro-fuzzy sliding mode controller (NFSMC) has been designed to control the position of the AMB system. Simulink models of the AMB with different control strategies have been developed for conducting simulation studies. The comparison results indicate that, with SMC, the position of the rotors follows the reference input but it is affected by chattering. It is further observed that FSMC reduces the chattering, while NFSMC controllers automatically eliminate the chattering problem and operate more robustly and smoothly. The system’s stability has been analyzed using the Lyapunov theorem. According to the results gained, the NFSMC improves the overall system performance. The NFSMC controller yields an optimal result having no overshoot, a settling time of 0.5 sec, and a rise time of 0.10 sec in comparison with FSMC controller which exhibits overshoot of 0.392%, a settling time of 0.75 sec, and a rise time of 0.133 sec, while the SMC shows overshoot of 9.047%, a settling time of 7.5 sec, and a rise time of 0.17 sec.

In order to improve the tracking ability of the vehicle mounted photoelectric tracking platform, and make its tracking system has the characteristics of rapid response, small overshoot, high-precision position tracking, strong anti-interference and good robustness. In this paper, a joint active disturbance rejection control (ADRC) and sliding mode control (SMC) method is proposed, which can effectively improve the tracking ability of the equipment. Firstly, the mathematical model of the DC motor is analyzed, and then the sliding mode control based on the linear extended state observer (LESO) and the third-order tracking differentiator is established as the speed loop control of the system. Finally, the parameters of the nonlinear ADRC which built control system’s position loop are optimized by the improved differential evolution (DE) algorithm. The speed loop simulation results show that the proposed algorithm has better control effect than PID control algorithm, Robust control algorithm, and ADRC control algorithm;The simulation of position loop demonstrates that the performance of the controller optimized by DE algorithm is better than the parameter tuning based on experience. The experimental results illustrate that the proposed control algorithm can ensure that the optoelectronic tracking equipment can track the target which 3km away with 0.1 mrad accuracy.

Soil is dynamic due to various internal and external processes exerted on the soil, resulting in unique soil characteristics in space in short and long distances. Geostatistics (kriging) is the method of quantifying the spatial variation of soil properties. This research was mainly aimed at applying geostatistics to quantify and interpolate the spatial dependence and structure of three soil properties, namely pH, EC, and Soil Moisture Content (SMC) in a small area. This research was conducted on paddy fields in Mlandingan Kulon Village, Situbondo Regency. Sampling was conducted on an area of 9.2 ha with 31 sample points. Normal data distribution was found for pH and EC, whereas this was not the case for SMC. The results of the analysis showed that most of the pH values were alkaline (>8), EC values were non-saline (

The grid-connected Doubly Fed Induction Generator (DFIG) system is exposed to severe grid faults. The DFIG is sensitive to grid disturbances, which lead to consideration in the controller design. This paper proposed the Modified Super Twisting (MST) algorithm for the Low Voltage Ride Through (LVRT) enhancement under voltage sag condition. This proposed algorithm is implemented using the 2nd Order Sliding Mode (SOSM) to control the DFIG based wind generator. The higher-order switching functions are introduced in the SOSM for sliding surface control. Moreover, the Lyapunov analysis for the MST algorithm brings down the chattering amplitude. The advantages of the proposed algorithm are that it reduces the system uncertainties, chattering effect and improves the settling period of the system parameters. The performance of the proposed algorithm is compared with existing algorithms in the literature with the help of MATLAB/SIMULINK. The Hardware-In-Loop (HIL) is used to validate the simulation results, which have been performed on the OPAL-RT setup. In addition, the proposed algorithm is also tested on an equivalent model of the practical Wind Farm (WF). Based on the studies, it is found that the proposed algorithm enhanced the LVRT performance of the single Wind Turbine (WT)-DFIG system as well as the practical WF under transient conditions.

With the rapid development of information technology,privacy-preserving multiparty cooperative computation is becoming more and more popular.Secure multiparty computation is a key technology to address such problems.In scientific research and practical applications,people measure the similarity of two strings with Hamming(edit) distance.It is of great significance to study privacy-preserving Hamming(edit) distance computation.This paper studies privacy-preserving Hamming(edit) distance computation.First,we transform Hamming distance computation to inner product computation of vectors,and then use Okamoto-Uchiyama(OU) cryptosystem and encryption-and-choose technique to design protocol for Hamming distance.Second,we give each alphabet of a string a number,transform edit distance to determine whether the difference of the number of two alphabets is 0,and use OU cryptosystem to design a privacy-preserving edit distance computation protocol.The security of the protocol is strictly proved,the computational complexity of the protocol is analyzed,the actual implementation efficiency of the protocol is tested and compared with the existing results.Theoretical analysis and experimental results show that our protocols are efficient.

This study represents a comparison of novel robust adaptive sliding mode control using stochastic gradient descent (ASMCSGD) versus the super twisting algorithm (STA) for the proton exchange membrane fuel cell (PEMFC) power system. PEMFC has been constantly encountered with external disturbances such as inlet gas pressures and temperature fluctuations which a novel adaptive control law should be designed to be robust against the mentioned perturbations. The proposed ASMCSGD is based on the conventional sliding mode control (SMC), which guarantees robustness and restraining external disturbances. As is common, the main drawback of conventional SMC is the generation of a chattering phenomenon. Therefore, by using the stochastic gradient descent (SGD), a novel adaptive control law is designed. Hence, the SGD can continuously calculate the adaptive gain and then guarantee robustness besides minimizing the chattering phenomenon. The stability of the PEMFC power system for both controllers ASMCSGD and STA is demonstrated via the Lyapunov theorem. Simulation results have been studied and illustrate the effectiveness of the proposed controller successfully using Matlab/Simulink. [Display omitted] • A novel adaptive sliding mode is established for a PEM fuel cell power system. • The adaptive sliding mode is compared with the STA. • Theoretical stability proofs were addressed for each controller. • Simulation results focused in robustness and reduction of chattering phenomenon. [ABSTRACT FROM AUTHOR]

The six-degree-of-freedom (6 DOF) motion of the mother-ship, which is caused by wave fluctuation, makes offshore operations difficult. To solve this problem, various heave compensation systems were proposed, as well as the law of wave motion. These heave compensation systems included passive heave compensation system, semi-active heave compensation system, and active heave compensation (AHC) system. However, the empirical formula of wave motion is not suitable for practical offshore operations, and rare AHC systems take the characteristic of compensation into consideration. To study the compensation characteristic of the AHC system based on electric-driven marine winch in the actual sea condition and improve the accuracy of compensation, this work uses the measured data of wave motion, and deduces the motion equations of multi-axial driving system. By substituting the above elements into the AHC system and designing the sliding mode controller (SMC), the simulation results show the ideal compensation effect of the system. By comparing with experimental results, it is concluded that the driving system operates in according with the specified states, and the compensation performance of system is effective. The overall work is conductive to the research on AHC system, as well as the exploitation of marine resources. [ABSTRACT FROM AUTHOR]

An exoskeleton robot is a sample of a wearable robot. One of the most critical challenges in developing wearable robots is the application of the interactive force between human and robot. Force sensors need to be placed on the robot. Consideration in using these sensors needs to be given to factors such as cost, noise, and weight. One way that can be used to help with the operation of the exoskeleton is to support the sensors with observers. This study will estimate the interactive force applied to a human arm model and the exoskeleton robot. The sliding mode control (SMC) method will be employed to design a chattering‐free robust fixed‐time controller and observer, for estimating the states of the human arm and exoskeleton robot. Utilizing this information from state observers, the interactive force is estimated. The state observer and the controller work together in real‐time (online estimation). The Lyapunov theory is used to show the fixed‐time stability analysis of the controller and the observer. Numerical simulation with three scenarios demonstrates the performance of the proposed design. [ABSTRACT FROM AUTHOR]

Summary: Sliding mode control is one of the common control methods for manipulators, but the discontinuity of sliding mode control can cause jitter and vibration of the manipulator system. This article takes the Dobot Magician manipulator as the research object and constructs a simplified model of the manipulator dynamics. And the adaptive fuzzy sliding mode control method is designed in combination with fuzzy control theory, which effectively solves the jitter problem of the control torque. In the MATLAB/Simulink simulation environment analysis show that the proposed adaptive fuzzy sliding mode control method solves the jitter problem in sliding mode control with good stability, robustness and tracking performance. By combining the adaptive fuzzy sliding mode control method with the manipulator and comparing the motion time of the same motion trajectory with the PID control method in Dobot Studio, the hardware experiment results effectively verify the feasibility and effectiveness of the designed control method. [ABSTRACT FROM AUTHOR]

The control of an autonomous underwater vehicle (AUV) is regarded as a difficult challenge, owing to the nonlinear and uncertain dynamics of the AUV. In this work, Optimized neural network (NN) is integrated with the "second-order sliding mode control (SoSMC) approach" for control of yaw angle in AUV. More particularly, the positive gain of SoSMC is predicted by an optimized NN model, where the training is performed by a novel Sea Lion Distance-based FireFly algorithm via tuning the optimal weights. At last, the supremacy of the adopted model is validated under various measures. Accordingly, the RMSE values accomplished by the proposed model is 40.94%, 1.39%, 0.69%, 0.69% and 0.41% better than existing models like "GW-SMC, FF-SoSMC, SLnO-SoSMC, POA-SoSMC and GW-SoSMC", respectively, for set point 1. [ABSTRACT FROM AUTHOR]

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One of the great concerns when tackling nonlinear systems is how to design a robust controller that is able to deal with uncertainty. Many researchers have been working on developing such type of controllers. One of the most efficient techniques employed to develop such controllers is sliding mode control (SMC). However, the low order SMC suffers from chattering problem which harm the actuators of the control system and thus unsuitable to be used in many practical applications. In this paper, the drawbacks of low order traditional sliding mode control (FOTSMC) are resolved by presenting a novel adaptive radial basis function neural network-based generalized rth order sliding mode control strategy for nth order uncertain nonlinear systems. The proposed solution adopts neural networks for their excellent capability in function approximation and thus used to approximate the nonlinearities and uncertainties for systems under consideration. The approximation errors are completely considered in the developed approach. The proposed approach can be used with any order of sliding mode and thus can be generally used with various types of applications. The global stability of the proposed control approach is proved through Lyapunov stability criterion. The proposed approach is validated and assessed through simulations on the nonlinear inverted pendulum system with severe modeling uncertainties. The simulations results show that the proposed approach provide superior performance compared with other approaches in the literature. [ABSTRACT FROM AUTHOR]

The bacterial chromosome is spatially organized through protein-mediated compaction, supercoiling, and cell-boundary confinement. Structural Maintenance of Chromosomes (SMC) complexes are a major class of chromosomeorganizing proteins present throughout all domains of life. Here, we study the role of the Escherichia coli SMC complex MukBEF in chromosome architecture and segregation. Using quantitative live-cell imaging of shape-manipulated cells, we show that MukBEF is crucial to preserve the toroidal topology of the Escherichia coli chromosome and that it is non-uniformly distributed along the chromosome: it prefers locations toward the origin and away from the terminus of replication, and it is unevenly distributed over the origin of replication along the two chromosome arms. Using an ATP hydrolysis-deficient MukB mutant, we confirm that MukBEF translocation along the chromosome is ATP-dependent, in contrast to its loading onto DNA. MukBEF and MatP are furthermore found to be essential for sister chromosome decatenation. We propose a model that explains how MukBEF, MatP, and their interacting partners organize the chromosome and contribute to sister segregation. The combination of bacterial cell-shape modification and quantitative fluorescence microscopy paves way to investigating chromosome-organization factors in vivo. [ABSTRACT FROM AUTHOR]

This study examines and evaluates how the government communicated the volcanic eruption that occurred in La Palma (Spain) in 2021. For that purpose, SCCT and the SMCC models were used to perform a content analysis of the online communication approach followed on Twitter by Cabildo de La Palma (@CabLaPalma), 112 Canarias (@112canarias), and the Spanish Home Office (@interiorgob). Findings suggest that these three institutions aligned their communications by using complementary strategies, message framings and styles to successfully handle the crisis. However, this study also highlights areas of improvement in the approaches taken by these three public entities.

The bacterial chromosome is spatially organized through protein-mediated compaction, supercoiling, and cell-boundary confinement. Structural Maintenance of Chromosomes (SMC) complexes are a major class of chromosome-organizing proteins present throughout all domains of life. Here, we study the role of the Escherichia coli SMC complex MukBEF in chromosome architecture and segregation. Using quantitative live-cell imaging of shape-manipulated cells, we show that MukBEF is crucial to preserve the toroidal topology of the Escherichia coli chromosome and that it is non-uniformly distributed along the chromosome: it prefers locations toward the origin and away from the terminus of replication, and it is unevenly distributed over the origin of replication along the two chromosome arms. Using an ATP hydrolysis-deficient MukB mutant, we confirm that MukBEF translocation along the chromosome is ATP-dependent, in contrast to its loading onto DNA. MukBEF and MatP are furthermore found to be essential for sister chromosome decatenation. We propose a model that explains how MukBEF, MatP, and their interacting partners organize the chromosome and contribute to sister segregation. The combination of bacterial cell-shape modification and quantitative fluorescence microscopy paves way to investigating chromosome-organization factors in vivo.

The main challenges of the input current control in synchronous DC-DC buck converters are the nonlinear model of the system, changes of the operating point in a wide range, and the need to use an input LC filter for current smoothing, which may result in the instability of the closed-loop system. In this paper, a step-by-step approach is developed for the design and improvement of a PI-feedforward closed-loop controller. It is shown that a linear PI controller cannot stabilize the closed-loop system properly during wide changes in model parameters, e.g., an equivalent series resistance of the input filter. To cope with the stability issues, a fixed-frequency sliding mode controller (SMC) has been developed in this paper for the implementation of an electro-mechanical actuator (EMA) emulator. Moreover, a systematic approach is proposed for controller tuning and the selection of the SMC's gains. To achieve high power efficiency, high-frequency GaN switches are used for the practical implementation of the DC-DC converter. Despite large changes in the load current, the designed nonlinear controller can track the input current reference satisfactorily. Steady-state and dynamic responses of the proposed SMC are compared with conventional linear controllers. Considering the Lyapunov stability theorem, it is proved that the designed SMC can stabilize the closed-loop system in the entire utilizable domain. The proposed nonlinear SMC controller enjoys a very simple control law. Hence, despite having very high switching and sampling frequencies, it can be easily implemented. The experimental response of the designed synchronous DC-DC buck converter is evaluated experimentally by implementing the control strategy in a TMS320F28335PGFA DSP from Texas Instrument. Moreover, the comprehensive comparison of the proposed SMC controller and a PI-feedforward controller proved the superior performance of the developed closed-loop system, in terms of the transient time response, robustness, and stability of the EMA emulator. [ABSTRACT FROM AUTHOR]

In this article, the synchronization problem of hyperchaotic systems is addressed on the basis of active sliding mode control (SMC) and proportional integral (PI) SMC techniques. The stability analysis in the suggested methodologies is derived with the help of Lyapunov stability approach. In the manuscript, a comparative study presenting both above mentioned SMC approaches has been presented. Further, both the SMC techniques have been stretched to analyze secure communication for hyperchaotic systems under consideration. Switching surfaces are constructed using active SMC and PI SMC to achieve the purpose of synchronization. Between both the control techniques, PI switching surface simplifies the operation of synchronization in comparison with active control switching surface. In PI SMC, lesser number of control signals are needed to achieve the desired synchronization. The system parameters have been considered to be known. In a master–slave arrangement, the suggested controllers assure the presence of sliding motion and attain asymptotic synchronization of hyperchaotic systems. Ultimately, numerical simulations are produced to establish and authenticate the suggested controllers' effectiveness. This paper presents the effectiveness of the two control approaches designed for addressing synchronization problems along with secure communication scheme. [ABSTRACT FROM AUTHOR]

Coalescent with recombination is one of the most important population models in population genetics. This model is very efficient for simulating realistic genealogies and genetic data. But due the complexity of its state space, in particular due to the combinatorial reasons, the inference under this model is computationally intensive and often infeasible. The Sequential Markovian Coalescent (SMC), and its modification SMC , are approximations to the full coalescent with recombination. Many methods use SMC for inference purposes, often by applying Hidden Markov Model framework. It was shown that SMC is a very accurate approximation of the coalescent with recombination in the case of a panmictic population. But in reality population histories are much more complex, in particular due to migrations. Here we investigate the accuracy of the SMC approximation in case of structured coalescent with recombination, more precisely in case of two populations with continuous symmetric migration between them. [ABSTRACT FROM AUTHOR]

Chaos is a phenomenon that occurs in some non-linear systems. Therefore, the output of the system will be heavily dependent on the initial conditions. Since the main characteristic of the chaos is an abnormal behavior of the system output, it should be considered in designing control systems. In this paper, controlling chaos phenomenon in a time-variant non-linear gear transmission system is investigated. To do this, a non-linear model for the system is introduced considering the effective parameters of the system, and then it is shown that chaos appears in the system by plotting phase plane of state-space variables. It should be noted that there is a great difference between random and chaotic behavior. In random cases, the model or input contains uncertainty, and therefore, the system behavior and output are not predictable. However, in chaotic behavior, there is only a brief uncertainty in the system model, input or initial conditions, and designing controller based on output prediction could be achieved. Therefore, model predictive control (MPC) algorithms are used to control the chaos, using the output prediction concept. In many cases, perturbation term also can be considered as uncertainty, and therefore, a robust controller family can be used for eliminating chaos. Both generalized predictive controller (GPC) and sliding mode controller (SMC) are used for chaos control here. The simulation results show the efficiency of the proposed algorithms.

• Current soil moisture indices (SMIs) are sensitive to VWC. • Vegetation-water Resistant SMI (VRSMI) insensitive to VWC. • VRSMI incorporates a physical relation between NIR and SWIR reflectance. • A linear relationship is found between soil VRSMI and soil moisture. • VRSMI supports SMC estimation under low-moderate crop cover. Soil surface moisture content (SMC) is one of the most critical and fundamental indicators of crop drought because water is vital for vegetation growth. In recent decades, satellite high-spatial-resolution optical multi-spectral remote-sensing sensors have entered a new stage. However, current optical remote sensing SMC indices (SMIs) are sensitive to cropland SMC and vegetation water content (VWC). From dry to saturated, the soil spectra decreased quickly as the SMC increased. For the vegetation spectra, the short-wave infrared (SWIR) bands decreased as the VWC increased. The differences in the responses of near-infrared (NIR) and SWIR bands to water may help distinguish soil moisture from mixed soil-vegetation spectra. This study focuses on (a) analyzing how soil and vegetation reflectance are affected by VWC and SMC, (b) designing a new vegetation-water resistant soil moisture index (VRSMI) based on the differences in the responses of NIR bands and SWIR bands to water, and (c) evaluating the potential of using VRSMI to remotely estimate SMC in low-moderate crop-covered regions. VRSMI uses SWIR1-SWIR2 as the numerator to detect the water absorption features and NIR×(SWIR1)0.5 as the denominator to weaken the vegetation effect. VRSMI and soil-VRSMI (VRSMIs) were tested using laboratory- and field-based spectra datasets. Our study presents the following conclusions: (1) The differences in the responses of NIR and SWIR bands to water help distinguish the effects of soil moisture on mixed soil-vegetation spectra. (2) VRSMIs can provide high-performance SMC estimates under low-moderate vegetation cover (NDVI < 0.55). (3) VRSMIs can be used for cropland SMC evaluation without considering crop VWC (laboratory-based spectra dataset: RMSE = 0.07–0.11, R 2 = 0.96–0.98; field-based spectra dataset: RMSE = 0.17–0.18, R 2 = 0.63–0.79). Our study indicates that VRSMI and VRSMIs can provide high-performance relative SMC estimates under low-to-moderate vegetation cover. [ABSTRACT FROM AUTHOR]

The main contribution of this article is creating synergy between subjects; this means that students use the same graphical tool in several subjects. So far, the bond graph has not been used in control theory, but it is the “native language” of mechatronics engineers, so we would like to introduce it into the teaching of control theory. The bond graph method is proposed as a novel teaching method to teach mechatronics subjects in the paper. The bond graph is a graphical alternative to ordinary differential equations from a mathematical standpoint. Traditionally, control theory employs ordinary differential equations, as they are familiar to control theorists. However, mathematically, both approaches are equivalent but require a slightly different approach in their application. This article highlights the mathematical similarities between the two approaches while emphasizing the distinctions in graphical representation. Another contribution is that the PID and sliding mode controller are represented using the bond graph method. In the meantime, through the use of practical examples, we effectively illustrate how the same problem can be solved using either approach. In the training materials, the PID controller and an adaptive robust sliding mode controller (ARSMC) with the bond graph are utilized as examples to demonstrate synergy in mechatronics. Finally, we present proof that mechatronic engineers achieve superior outcomes when utilizing the bond graph approach, based on test results from undergraduate students.

The employment of input filters in modern DC–DC converters is mandatory in order to ensure EMC (Electro-Magnetic Compatibility), provide power electronics with decent voltage and minimize the converter influence on the power grid. The LC type input filters bring also a possibility of voltage and current oscillation that may occur in the system. This oscillation may rise to a certain level that affects system stability. A wide range of methods are employed in order to attenuate these oscillations and allow appropriate system transient response. In this paper, the sliding mode control (SMC) strategy is proposed to reduce the input LC filter voltage and current oscillation and allow DC (Direct Current) output voltage control for both resistive and constant power load. The proposed control algorithm is intended for use in railway, tram and trolleybus DC/DC converters. For the proposed scheme of control simulation, a model is developed using Simulink software. Furthermore, laboratory stand experiments are carried out to verify simulation results.