Switching System Research Articles

Exploring Nano-optical Molecular Switch Systems for Potential Electronic Devices: Understanding Electric and Electronic Properties through DFT-QTAIM Assembly.

The design and synthesis of molecular nanoswitches using organic molecules represent a crucial research field within molecular electronics. To understand the switching mechanisms, it is essential to investigate various factors, such as charge/energy transfer, electron transfer, nonlinear optical properties (NLO), current-voltage (I-V) curves, Joule-like (LJL) and Peltier-like (LPL) intramolecular phenomenological coefficients, as well as the energy levels of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) boundary orbitals. In this Article, a novel approach to designing a molecular nanoswitch and understanding its ON/OFF mechanism is presented, utilizing the quantum theory of atoms in molecules (QTAIM), density functional theory (DFT), and Landauer theory (LT). These analyses contribute significantly to a deep understanding of switching effects within molecular electronic systems.

Robust Guaranteed Cost Composite Anti-bump $$L_2$$-Gain Control for a Class of Switched Systems Under Mixed State-Dependent Switching

Robust Guaranteed Cost Composite Anti-bump $$L_2$$-Gain Control for a Class of Switched Systems Under Mixed State-Dependent Switching

Attack-compensated asynchronous output feedback control for stochastic switching systems with sojourn probability

This study addresses the problem of attack-compensated asynchronous output feedback control for stochastic switching systems with sojourn probability. Unlike traditional Markov/semi-Markov models that rely on transition probabilities, a novel switching rule is introduced that focuses on sojourn probability information associated with the target mode and sojourn time, which are easier to obtain than the well-known transition probabilities. Considering the vulnerability of stochastic switching systems to cyber-attacks, where the system state becomes unobservable and difficult to manage, a compensation-based output feedback controller framework is proposed. Using the Lyapunov method and stochastic analysis, sufficient conditions are provided to ensure system stability. Finally, the effectiveness and applicability of the developed approach are demonstrated using an F-404 aircraft engine system model.

Developing an off-on fluorescence sensor based on red copper nanoclusters wrapped by sulfhydryl and polymer double ligands for sensitive detection of N-acetyl-L-cysteine

N-acetyl-L-cysteine (NAC) as a class of thiols is commonly used in the treatment of lung diseases, detoxification and prevention of liver damage. In this paper, 4-mercaptobenzoic acid (4-MBA) coated and polyvinylpyrrolidone (PVP) attached copper nanoclusters (4-MBA@PVP-CuNCs) were successfully synthesized using a simple one-pot method with an absolute quantum yield of 10.98 %, and its synthetic conditions (like effects of single/double ligands and temperature) were studied intensively. Then Hg2+ could quench the fluorescence of the 4-MBA@PVP-CuNCs and its fluorescence was restored with the addition of NAC. Based on the above principles, an off–on switching system was established to detect NAC. That is, the 4-MBA@PVP-CuNCs-Hg probe was prepared by adding Hg2+ to switch off the fluorescence of the CuNCs by static quenching, and then NAC was added to switch on the fluorescence of the probe based on the chelation of NAC and Hg2+. Moreover, the effects of metal ion types and mercury ion doses for the probe construction were also further discussed. The method showed excellent linearity in the range of 0.05–1.25 µM and low detection limit of 16 nM. Meanwhile, good recoveries in real urine, tablets and pellets were observed, which proved the reliability of the method and provided a convenient, fast and sensitive method for NAC detection.

Smc for discrete delayed semi-Markov switching systems

Smc for discrete delayed semi-Markov switching systems

A new numerical simulation method of 3D rough surface topography with coupling 3D roughness parameters Sdr, Sdq, Spd, Spc, and characteristic functions

The existing surface topography modeling methods based on random process theory make it difficult to realize the coupling of three-dimensional roughness parameters Sdr, Sdq, Spd, and Spc in ISO25178, which are related to the friction and lubrication performance of parts. The paper proposes constraints set for the structure of spatial features in height matrix discrete points during the random switching process, and the accurate coupling of parameters Sdr, Sdq, Spd, and Spc with characteristic functions is achieved by the improved random switching system. The new method is applied to simulate four kinds of finishing surface topography numerically, and the results show that the relative errors of these four parameters are effectively reduced from 5–110 % to 1 %.

Transient stability of grid following inverters: The impacts of damping and fault ride‐through

AbstractThe interaction of grid following inverters with a weak grid raises risks of transient instability. The effects of damping and fault‐ride through (FRT) make the transient dynamics more complicated. To investigate the impact of FRT on the transient stability of converters, this paper first employs the switch system theory to construct a mathematical model for the synchronous mechanism of inverters. Secondly, the method of semi‐algebraic system real root classification is comprehensively used to analyse the existence of equilibrium points (EPs) and provide necessary and sufficient conditions for their existence. Finally, based on the theory of differential geometry, a method for computing the stability domain of converters is proposed. Compared with traditional methods, the results obtained from this approach are precise and non‐conservative. The study in this paper indicates that the equivalent damping effect from the proportional control in a phase‐locked loop significantly enlarges the stability region, whereas the active current injection shrinks the stability region. The reactive current droop characteristic also has impacts on the stability region, especially with active current injection. The switchover between the droop mode and constant current mode requires extra precaution in the calculation of the EPs and critical fault clearing time.

Distribution of Sports Load by the Smart Photovoltaic Cell Switching System

In order to discuss the allocation effect of anintelligent photovoltaic cell switching system on sports load, thispaper, based on the ZigBee sensing model, designs theinformation allocation module for collecting sports load statusbased on the spectral characteristic analysis of model parametersand the real-time observation of sports load status, and obtainsthe initial data. In-depth analysis of the correlation analysis ofintelligent photovoltaic cell switching system on sports loadallocation, and judge the influence degree of sports loadallocation. The results show that in the monitoring of sports loadstatus, the data acquisition frequency of 28 to 30 kHz can reach -50 dB, and the maximum oxygen uptake VO2, the number ofmax indicators reached 33.21 ± 3.09 and O2, the number of Pindicators is 362.57 ± 98.71, and the number of METs is 9.06 ±1.21. Therefore, we show that the smart photovoltaic cellswitching system has a positive correlation with the sports loaddistribution, and the smart photovoltaic cell switching system hasa practical effect on the sports load distribution.

(Invited) Engineering the Switching Kinetics of Valence Change-Based Memristive Devices for Neuromorphic Computing

Memristive devices based on the valence mechanism are highly interesting candidates for the use as hardware representation of synapses in neuromorphic computing. The memristive model system SrTiO3 exhibit gradual switching and can be tuned between short-term and long-term plasticity. We will discuss the impact of the switching kinetics on the gradual switching mode and provide general guidelines for the design of gradual switching systems. Moreover, we present an approach to accelerate the switching kinetics of SrTiO3 by up to 103 times, or reduce the operating voltage by ≈ 30% to maintain the switching speed.Our approach is to introduce a low thermal conductivity layer inside the active electrode of the active electrode of the devices, which blocks the heat dissipation caused by Joule heating during switching. Our method leaves the switching layer and its interfaces with the electrodes intact, while the use of HfO2 and TaOx as the heat blocking layers ensures ease of fabrication and CMOS compatibility. We will demonstrate that this approach is transferable to other more common material systems.

Embedded system controlled switching system for reconfigurable antennas

AbstractA multiband and reconfigurable antenna is the one of the main aspects in the communication system which has an extremely important role. An embedded based solution for the fast operation of a reconfigurable antenna to work in a specific operating frequency band is the solution of future technologies. Embedded based solution increases the speed by avoiding the dependence on manual control of the RF switching elements. In this paper, the proposed embedded system‐controlled switching mechanism operate the reconfigurable antenna in any one of the operating bands by a single command to be send from a remote location. The embedded system receives the command and configure a set of PIN diodes as per the modes. The proposed solution consists an Arduino UNO board as motherboard, SIM900A as GSM module to receive the command from user, biasing circuit to control the operation of PIN diode, PIN diode to reconfigure the patch pattern and a user mobile for sending AT command.The proposed model is successful and tested on proteus software 8.0. The model is also deployed on the newly designed multiple‐input‐multiple‐output antenna where the result shows the successful operation to achieve multiband frequency operation.

$$H_\infty $$ Reliable Bumpless Transfer Control for Switched Systems: A Mixed State/Time Dependent Switching Method

$$H_\infty $$ Reliable Bumpless Transfer Control for Switched Systems: A Mixed State/Time Dependent Switching Method

Thermodynamic characteristics of a novel solar single and double effect absorption refrigeration cycle

Solar absorption refrigeration systems provide one of the economical options for air conditioning. In order to reduce the complexity and economic cost, a more advanced solar single-double-effect switching system is proposed. The innovation of this system is that it replaces the single-effect and high-pressure generators in previously developed single-double-effect switching system with a specific generator. The optimal heat source switching temperature of the new system was determined by the genetic algorithm to be 125.5 °C. Compared with the original single-double-effect switching system, the average coefficient of performance of the system is increased by 8.6 %, and the fluctuation of refrigeration capacity during the switching period is reduced by 48 %. The new solar single-double-effect switching system is investigated based on thermodynamic characteristics, energy, exergy, and economy aspects. The results showed that heat exchangers of the system have strong coupling. The cooling water temperature has a greater impact on the performance of the dual-effect mode. In the single-effect mode, the special-pressure generator has the largest exergy destruction (39 %), while in the double-effect mode, the absorber has the largest exergy destruction (41 %). Besides, the economic analysis demonstrated that the new system is economically viable with a payback period of 9.33 years.

A Petri nets-based modeling method for multi robot path planning

The construction of lunar bases is one of the core enabling technologies in current lunar exploration and development plans of various countries. However, to eliminate the constraints of high transportation costs and limited manned space technology, a new research plan is to employ multi robot teams to build lunar bases. The key to this solution is how to achieve path planning for complex tasks for multiple robots. Therefore, this article takes the exploration and collection area, lunar soil collection, and lunar soil transportation in the lunar base construction scene as complex task inputs, and studies a multi robot path planning modeling method based on Petri net model. Firstly, a Petri net model for multi robot motion was constructed. Meanwhile, linear temporal logic(LTL) language was used to describe the related tasks of lunar base construction. Finally, simulation validation was conducted in Matlab software and compared with the modeling method using switching systems. The results show that the total modeling time required for using the Petri net model is reduced by two orders of magnitude compared to the modeling time for a single task switching system model, indicating that the established Petri net multi robot model has advantages such as avoiding dimension explosion and computational efficiency.

Generalized flow calculation of the gas flow in a network of capillaries used in gas chromatography.

A general method for the calculation of the flow and pressure of a gas in a network of cylindrical capillaries is presented. This method is used specifically for gas chromatographic systems in this work. With this approach, it is possible to easily calculate flow and pressures in complex gas chromatographic systems, like flow-modulated or thermal-modulated multidimensional gas chromatographic systems, or systems with multiple outlets at different pressures. A mathematic abstraction using graph theory is used to represent the system of capillaries. With this graph, the flow balance equations at the connections of the capillaries can easily be set up. Using a computer algebra system, the system of flow balance equations can be solved for the pressures at the connection points. For simple systems, this approach is presented, and calculated flows, pressures, and hold-up times are compared with measured values. In addition, two complex systems (4-Way-Splitter, Deans Switch system) of capillaries are presented with calculations only. For these systems, certain conditions were formulated, that is, a certain difference in hold-up times and a defined split ratio between different paths of these systems. Using a numeric non-linear solver, configurations of these systems were found, that fulfill these conditions.

Stabilization of Networked Switched Systems Under DoS Attacks.

This article studies the stability issue of networked switched systems (NSSs) under denial-of-service (DoS) attacks. To address this issue, the derived limitations imposed on both the frequency of DoS attacks on each subsystem and the upper limit of attack duration that each subsystem can tolerate are mode-dependent, which is more efficient and flexible than the current results for NSSs. Moreover, we reveal the relationship between the upper bound of the average maximum tolerable attack duration associated with the corresponding subsystem and the actual mode-dependent average dwell time. Furthermore, we identify that the total tolerable DoS attack duration as a percentage of the system runtime in this article can be higher than existing results. Finally, an example is given to demonstrate the effectiveness of our work.

Stability analysis and anti-windup design of saturated switching systems based on multiple Lyapunov functions

Abstract In this paper, employing advanced multiple Lyapunov functions (MLF) technology, we conduct a thorough investigation into the fault-tolerant characteristics of actuator saturation-based systems, particularly those prone to failures. Based on this comprehensive analysis, we carefully design an anti-windup (AW) controller, incorporating an efficient AW compensator and precisely calibrated gains for the dynamic state feedback controller, tailored to meet the specific needs of practical control systems. To further demonstrate the effectiveness of our approach, we also provide a detailed numerical example.

Robust Switching Time Optimization for Networked Switched Systems via Model Predictive Control.

This article presents a model predictive control (MPC) strategy to find the optimal switching time sequences of networked switched systems with uncertainties. First, based on predicted trajectories under exact discretization, a large-scale MPC problem is formulated; second, a two-level hierarchical optimization structure coupled with a local compensation mechanism is established to solve the formulated MPC problem, where the proposed hierarchical optimization structure is actually a recurrent neural network consisting of a coordination unit (CU) at the upper level and a series of local optimization units (LOUs) related to each subsystem at the lower level. Finally, a real-time switching time optimization algorithm is designed to calculate the optimal switching time sequences.

Design of switching system between LED light and pulsed laser at the cold light source end of hysteroscopy

Design of switching system between LED light and pulsed laser at the cold light source end of hysteroscopy

Wavelength-selective, time-resolved, and visible-light-responsive multicolor switching systems for multistate dynamic information encryption

Visible-light-responsive photoreversible multi-color switching systems (PMCSSs) are attractive to meet the advanced demands in dynamic information encryption. Particularly, PMCSSs with wavelength-selective and time-resolved color switching are highly important but underexplored. Here, a new strategy is proposed to realize wavelength-selective, time-resolved, and visible-light-responsive PMCSSs by integrating acetamide ligand-capping CdS (CdS-NH2) nanoparticles and various redox dyes in solid films for multistate dynamic information encryption. The –NH2 groups of surface-bounded CH3CONH2 act as sacrificial electron donors for scavenging photogenerated holes to endow the CdS-NH2 nanoparticles high photoreductive ability and activity in a broad visible light range from 400 to 515 nm, thus enabling the long-waited wavelength-selective multicolor switching via coupling the wavelength-dependent photoreductivity of CdS-NH2 nanoparticles and the discoloration kinetics of redox dyes, such as methylene blue (MB) and phenosafranine (PS). Moreover, the time-dependent color switching during recoloration process of the color switching system can be modulated by tuning the oxidation kinetics of MB and methylene green (MG), enabling time-resolved dynamic imaging characteristics. Based on the unusual properties of the PMCSSs, a kind of wavelength-selective and time-resolved codes are designed for advanced dynamic information encryption. This work provides new guidance for developing of new PMCSSs for information encryption with high security requirements.

Anti-Disturbance Bumpless Transfer Control for a Switched Systems via a Switched Equivalent-Input-Disturbance Approach

This paper concentrates on the issue of anti-disturbance bumpless transfer (ADBT) control design for switched systems. The ADBT control design problem refers to designing a continuous controller and a switching rule to ensure the switched system satisfies the ADBT property. First, the concept of the ADBT property is introduced. Then, via a switched equivalent-input-disturbance (EID) methodology, a switched EID estimator is formulated to estimate the impact of external disturbances within the switched system. Second, a bumpless transfer control is then constructed via a compensator integrating an EID estimation. Finally, the effectiveness of the presented control scheme is verified by controlling a switching resistor–inductor–capacitor circuit on the Matlab platform. Above all, a new configuration for ADBT control of switched systems is established via a switched EID methodology.