Mode Switching Research Articles

Pulsed field ablation in patients with cardiac implantable electronic devices: an ex vivo assessment of safety.

Pulse field ablation (PFA) is a novel catheter ablation technology with potential safety benefits due to its tissue selectivity. It has the potential to directly damage or interact with the functionality of cardiac implantable electronic devices (CIEDs) in the form of electromagnetic interference (EMI). The aim of our study was to assess the impact of PFA on CIEDs. PFA lesions (45 per CIED) were applied from the Farapulse system to CIEDs (< 5 cm from the lead tip and < 15 cm from the generator). All devices were checked before and after PFA application for proper sensing and pacing functionality as well as for integrity of shock circuits in ICDs using a heart simulator. Moreover, devices were then interrogated for any spontaneous reprogramming, mode switching or other EMI effects. In total, 44 CIEDs were tested (16 pacemaker, 21 ICDs, 7 CRT-P/D) with 1980 PFA applications. There was no change in device settings, functionality and electrical parameters, and there was no macroscopic damage to the devices. The risk of damage to the electric components or leads on a patient-based analysis is 0/44 (95% CI 0-8%) and on a PFA pulse-based analysis is 0/1980 (95% CI 0-0.2%). Clinically relevant EMI appeared with oversensing and pacing inhibition but not tachycardia detection. Bipolar PFA appears safe and does not result in damage to CIEDs or leads. Clinically relevant EMI does occur, but appropriate peri-procedural programming may mitigate this. In vivo studies are needed to confirm our findings.

Sliding mode control for uncertain fractional-order reaction–diffusion memristor neural networks with time delays

This paper investigates a sliding mode control method for a class of uncertain delayed fractional-order reaction–diffusion memristor neural networks. Different from most existing literature on sliding mode control for fractional-order reaction–diffusion systems, this study constructs a linear sliding mode switching function and designs the corresponding sliding mode control law. The sufficient theory for the globally asymptotic stability of the sliding mode dynamics are provided, and it is proven that the sliding mode surface is finite-time reachable under the proposed control law, with an estimate of the maximum reaching time. Finally, a numerical test is presented to validate the effectiveness of the theoretical analysis.

GazeSwitch: Automatic Eye-Head Mode Switching for Optimised Hands-Free Pointing

This paper contributes GazeSwitch, an ML-based technique that optimises the real-time switching between eye and head modes for fast and precise hands-free pointing. GazeSwitch reduces false positives from natural head movements and efficiently detects head gestures for input, resulting in an effective hands-free and adaptive technique for interaction. We conducted two user studies to evaluate its performance and user experience. Comparative analyses with baseline switching techniques, Eye+Head Pinpointing (manual) and BimodalGaze (threshold-based) revealed several trade-offs. We found that GazeSwitch provides a natural and effortless experience but trades off control and stability compared to manual mode switching, and requires less head movement compared to BimodalGaze. This work demonstrates the effectiveness of machine learning approach to learn and adapt to patterns in head movement, allowing us to better leverage the synergistic relation between eye and head input modalities for interaction in mixed and extended reality.

Engineering Light‐Driven Rod‐Shaped Micromotors for Exhibiting Controlled and Tunable Multimode Swimming

AbstractThe recent era of research has been focused on attaining precise and adjustable propulsion modes in micromotors, with remarkable implications in microrobotics and active‐matter applications. This study introduces a novel design of rod‐shaped micromotors featuring light‐driven motion and wavelength‐dependent multimodal swimming behavior. The micromotors are fabricated through the Glancing Angle Deposition (GLAD) technique, which offers a flexible approach to engineering surfaces by incorporating photocatalytic materials (TiO2 and Cu2O) at specific locations. Here, three distinct designs of micromotors (titania, hybrid‐1, and hybrid‐2) are presented that are programmed to showcase diverse behaviors of movements (linear, helical, and axial rotation) when exposed to a specific wavelength. The application of light facilitates convenient control over activity and mode switching by altering between UV and visible ranges. Numerical modeling using a finite element approach is performed to validate the experimental results, demonstrating excellent agreement with the experimental findings. The present study is anticipated to be helpful in tailoring such complex micro/nanoscale advanced functional materials with intricating swimming modes desired for various applications in micro/nanorobotics.

Choice or Constraint? A Locally Tailored Assessment of Housing and Transportation Costs in Central Texas

Transportation costs are a key component of an overall household budget. These costs are determined in part by residential location—housing and transportation costs are inextricably linked. The burden of high housing and transportation costs must be understood in context. High costs on their own are not necessarily a problem if a household freely chooses their location. Although several national-level tools (including the Center for Neighborhood Technology’s H+T Index and the U.S. Department of Housing and Urban Development’s Location Affordability Index) are now available to improve transparency about combined housing and transportation costs, their ability to reflect local conditions and to understand relative burdens is limited. In this paper, we create a combined housing and transportation cost index tailored to the realities of the Austin metropolitan area in Central Texas, with most data sources coming from state and local government or pertinent transportation agencies. We identify households allocating large shares of their budgets to housing and transportation costs and differentiate between those that have the ability to mode switch to reduce costs in principle and those that do not. Black and Hispanic/Latino households were disproportionately burdened by high costs. But across the entire population, overall cost burdens were low. This result means that fostering nonautomobile travel or denser residential living will be challenging using cost arguments alone.

Seamless multi‐mode switching controller of four‐switch buck–boost converter based on integrated natural trajectory method

SummaryWith the characteristics of high efficiency and high power density, the four switch buck–boost (FSBB) converter is widely used in electric vehicles, direct current microgrids, and so forth. However, how to achieve smooth switching between different modes of FSBB has always been a hot issue in the theoretical and engineering fields. In this paper, considering the dynamic performance and output voltage or inductance current deviation, a control algorithm with integrated natural trajectory method is designed to realize the switching of different modes of FSBB converter. The proposed control algorithm is based on the theory of large signal natural locus and average natural locus. The normalized phase locus of inductance current and output voltage divides the phase plane into five regions and performs large signal or average switching operations in different regions. Theoretical analysis shows that the proposed control algorithm can achieve the balance between the dynamic performance and output voltage or inductance current deviation of FSBB converter in different mode switching. Finally, the performance of the proposed control algorithm is verified by experiments results.

Polarization‐Enhanced Narrow‐Band GeS2 2‐D SWIR Spectral Phototransistor

AbstractIntegrated computational spectrometers with gate‐tunable nano heterostructures and reconstruction algorithms are attractive for on‐chip gas‐sensing spectrometers and have enabled versatile spectrum detectors. However, they require the selective and optical filtering capabilities of wavelengths, restricting their efficient implementation in narrow‐band photodetection. In this study, a printable spectral phototransistor is developed with high dynamic detectivity (1012 Jones and 105 Hz at −3 db bandwidth) modulated by a GeS2 nanosheet heterostructure at short‐wave infrared (SWIR) regime. Using the transport mode switching of carriers in a heterostructure and the polarization‐sensitivity of the GeS2 two‐dimension (2‐D) nanosheet, this SWIR spectral phototransistor demonstrates an accurate narrow‐band selective (96.7% accuracy) spectrum detector and performed a deep‐learning analysis of an artificial neural network (ANN). Furthermore, this GeS2 2‐D based spectral phototransistor, characterized by its high in‐plane anisotropy and electrically reconfigurable properties, extends the applicability of narrow‐band photodetection with 15 nm Full Width at Half Maximum (FWHM) to the recognition of trace‐gases at the parts per billion (ppb) level.

Nonlinear dynamic modeling and analysis of the fluid-transporting cracked pipe using the hybrid semi-analytical and finite element method

The fatigue cracks may develop in the pipe systems due to long-term cyclic loading, which may cause catastrophic accidents. The finite element method (FEM) is usually adopted to simulate the stress singularity and breathing effect, resulting in expensive computational costs. Therefore, in this paper, an efficient hybrid semi-analytical and finite element (SA-FE) method is proposed to study the nonlinear dynamic characteristics of the fluid-transporting cracked pipe (FTCP) considering the breathing effect. Furthermore, the crack sensitivity parameters are obtained through bending-bending and bending-axial vibration analysis. For the SA-FE method, the semi-analytical method (SAM) and FEM are separately used to construct the dynamic models of the non-cracked and cracked regions, and the connection at the interface is performed by constraint equations. Subsequently, the validity of the modeling method is substantiated through both FEM and experimental tests. Finally, the effects of crack and fluid parameters on the dynamic characteristics of the FTCP are analyzed. The results indicate that changes in crack positions may trigger different-order mode switching, and continuous switching may occur between higher-order modes. In addition, the bending-bending and bending-axial coupling responses can effectively detect crack failures of the FTCP with varying levels of damage. The proposed model can offer valuable insights for fault diagnosis and health monitoring of FTCP.

Rapid mode switching facilitates the growth of Trichodesmium: A model analysis

Trichodesmium is one of the dominant dinitrogen (N2) fixers in the ocean, influencing global carbon and nitrogen cycles through biochemical reactions. Although its photosynthetic activity fluctuates rapidly, the physiological or ecological advantage of this fluctuation is unclear. We develop a metabolic model of Trichodesmium that can perform daytime N2 fixation. We examined (1) the effect of the duration of switches between photosynthetic and non-photosynthetic cellular states and (2) the effect of the presence and absence of N2 fixation in photosynthetic states. Results show that a rapid switch between photosynthetic and non-photosynthetic states increases Trichodesmium growth rates by improving metabolic efficiencies due to an improved balance of C and N metabolism. This provides a strategy for previous paradoxical observations that all Trichodesmium cells can contain nitrogenase. This study reveals the importance of fluctuating photosynthetic activity and provides a mechanism for daytime N2 fixation that allows Trichodesmium to fix N2 aerobically in the global ocean.

Transparent ionic liquid antenna based on multi-modes using multiple feeding structures

With the rapid development of modern wireless communication technology, there is an increasing demand for the functionality of the communication system carried by a single platform. To improve the utilization of the antenna, a multimode liquid antenna is proposed in this paper. The antenna is fabricated using 3D printing technology and mainly consists of a cylindrical dielectric resonator, a coaxial feeding structure, and a slot-coupling feeding structure. By hollowing out the middle of a resin container and filling it with low-loss ionic liquid with stable dielectric properties, a liquid dielectric resonator antenna (DRA) is formed. The various resonant modes (slot mode, HEM11δ, TM11δ, TM21δ, and TM31δ modes) can be excited by introducing different feeding structures. The operating frequencies and radiation patterns can be modulated by mode switching. Simulated and measured results show that the antenna operates in the frequency bands of 2.25–2.76 GHz (20.4 %) and 4.82–5.73 GHz (17.3 %), and the maximum gain can be up to 10.3 dBi. The proposed antenna structure avoids the complex RF control circuit design, which has various applications including 5G/6G communications, transparent electronic devices, and Internet of Things.

The Study of Mode-switching Behavior of PSR J0614+2229 Using the Parkes Ultra–wide-bandwidth Receiver Observations

In this paper we present a detailed single-pulse and polarization study of PSR J0614+2229 based on the archived data observed on 2019 August 15 (MJD 58710) and 2019 September 12 (MJD 58738) using the ultra−wide-bandwidth low-frequency receiver on the Parkes radio telescope. The single-pulse sequences show that this pulsar switches between two emission states, in which the emission of state A occurs earlier than that of state B in pulse longitude. We found that the variation in relative brightness between the two states varies temporally and both states follow a simple power law very well. Based on the phase-aligned multifrequency profiles, we found that there is a significant difference in the distributions of spectral index across the emission regions of the two states. Furthermore, we obtained the emission height evolution for the two emission states and found that, at a fixed frequency, the emission height of state A is higher than that of state B. What is even more interesting is that the emission heights of both states A and B do not change with frequency. Our results suggest that the mode switching of this pulsar is possibly caused by changes in the emission heights that alter the distributions of spectral index across the emission regions of states A and B, resulting in frequency-dependent behaviors, i.e., intensity and pulse width.

A Distributed Learning-Based Economic Dispatch Approach of Microgrids Considering Operational Mode Switch

A Distributed Learning-Based Economic Dispatch Approach of Microgrids Considering Operational Mode Switch

Design and characterization of a new high-count wide-range fission chamber based on GEM

As one of the main detectors for monitoring neutron flux rate in a nuclear reactor, the fission chamber (FC) suffers from issues such as low sensitivity, limited counting rate dynamic range, and system mode switching is cumbersome. This study utilizes the advantages of gas electron multipliers (GEM), which are easy to fabricate in large areas and have high counting rates, to design a novel fission chamber. By conducting Monte Carlo simulations on parameters such as the thickness of the 235U coating, the drift distance, and the operating electric field strength, a wide-range fission chamber design that combines high sensitivity and a counting rate range based on GEM has been obtained. The simulation results demonstrated that using a GEM detector to build a fission chamber can significantly improve sensitivity and extend the counting rate range. Subsequently we built a proof-of-concept GEM-based fission chamber and tested it with a 55Fe low-energy X-ray source and an Am-Be neutron source. The results showed that the proof-of-concept detector had a good signal-to-noise ratio and energy linearity, as well as clear discrimination between alpha background and neutron pulse amplitudes.

Towards Safe Autonomy in Hybrid Traffic: Detecting Unpredictable Abnormal Behaviors of Human Drivers via Information Sharing

Hybrid traffic which involves both autonomous and human-driven vehicles would be the norm of the autonomous vehicles’ practice for a while. On the one hand, unlike autonomous vehicles, human-driven vehicles could exhibit sudden abnormal behaviors such as unpredictably switching to dangerous driving modes—putting its neighboring vehicles under risks; such undesired mode switching could arise from numbers of human driver factors, including fatigue, drunkenness, distraction, aggressiveness, and so on. On the other hand, modern vehicle-to-vehicle (V2V) communication technologies enable the autonomous vehicles to efficiently and reliably share the scarce run-time information with each other [ 1 ]. In this article, we propose, to the best of our knowledge, the first efficient algorithm that can (1) significantly improve trajectory prediction by effectively fusing the run-time information shared by surrounding autonomous vehicles, and can (2) accurately and quickly detect abnormal human driving mode switches or abnormal driving behavior with formal assurance without hurting human drivers’ privacy. To validate our proposed algorithm, we first evaluate our proposed trajectory predictor on NGSIM and Argoverse datasets and show that our proposed predictor outperforms the baseline methods. Then through extensive experiments on SUMO simulator, we show that our proposed algorithm has great detection performance in both highway and urban traffic. The best performance achieves detection rate of 97.3%, average detection delay of 1.2 s, and 0 false alarm.

Self-Switching Wireless Power Transfer System Design with Constant Current/Constant Voltage Output Features Based on LCC-LCL/S Topology

To meet the demand for constant current and constant voltage charging of batteries and to increase the system output power, the LCC-LCL/S-type self-switching wireless power transfer system is proposed. The system does not require communication between the primary and secondary circuits, and its output mode is controlled by simply changing the status of two switches on the secondary side. Notably, the system satisfies the zero phase angle characteristic before and after mode switching. The parameter design method is proposed based on the circuit topology and the maximum safe current constraint. To make the output voltage fluctuation as small as possible, the optimum load switching point for the system has been designed, and its optimality has been validated by simulation. Furthermore, the switching control strategy is proposed, considering the effects of the system no-load and load short-circuit in real situations. Finally, an experimental platform was built to achieve the high efficiency output of the system with the maximum output voltage of 46.21 V, the maximum output power of 180 W, and the maximum efficiency of 93.4%, which verified the applicability of the proposed method.

A Novel reaching law sliding mode control method of PMSM considering iron loss

The loss of motor is ignored in the traditional speed control, while the loss minimization control (LMC) takes the high efficiency of the motor and does not consider the speed performance. Therefore, with the iron loss torque as the bond between efficiency and dynamic performance, this paper presents a sliding mode control method under the loss minimization target to achieve the high efficiency and high dynamic performance of permanent magnet synchronous motor (PMSM). Firstly, a d-axis current compensation method based on Taylor series expansion of virtual power loss (VPL) is proposed to minimize the loss of PMSM. Secondly, to eliminate the influence of iron loss on the speed performance, a PMSM speed tracking model including iron loss is established. Then, an adaptive sliding mode reaching law with disturbance estimation (ASMRLDE) is proposed to avoid energy consumption and the sliding mode chattering of the system caused by excessive sliding mode switch gain by adjusting the speed at which the system state reaches the sliding surface. Finally, the superiority of the proposed sliding mode control method under the loss minimization target in terms of loss minimization and speed control of the motor is proved through multi-condition experiments.

An estimation method for switching points of multimode spatiotemporal data based on SFSTAR

Various traditional methods, including statistical and spatial map-based approaches, are employed to model spatiotemporal data. However, the lack of explicit descriptions of spatial and temporal dependencies leads to unnecessarily intensive and uninterpretable relationships among the variables. To address this problem, space–time autoregressive moving average (STARMA)-type models that can depict temporal and spatial dependencies in a parametric manner are adopted in this study. However, such models may not be applicable to unlabeled multimode spatiotemporal data. In this study, we propose a switching flexible space–time autoregressive (SFSTAR) model to describe multimode spatiotemporal data. Considering the coupling between the parameter estimation of each mode and determination of the switching points, an estimation method is proposed to identify the mode switching points to partition the multimode data into different segments. First, the proposed estimation method identifies the number of segments by locating the transition regions that enclose the switching points based on the spatiotemporal feature extraction proposed herein. Second, with the estimated number of segments that is actually the number modes and the constraints on the locations of the switching points given by the transition regions, the proposed method jointly estimates the switching points and the SFSTAR model parameters in each mode through Bayesian optimization. The effectiveness of the proposed method is evaluated using a numerical example and a fiber optic temperature measurement dataset.

Asymmetric nucleation processes in spontaneous mode switch of active matter

Flocking and vortical are two typical motion modes in active matter. Although it is known that the two modes can spontaneously switch between each other in a finite-size system, the switching dynamics remain elusive. In this work, by computer simulation of a two-dimensional Vicsek-like system with 1000 particles, we find from the perspective of the classical nucleation theory that the forward and backward switching dynamics are asymmetric: going from flocking to vortical is a one-step nucleation process, while the opposite is a two-step nucleation process, with the system staying in a metastable state before reaching the final flocking state.

A decentralized coordinated control scheme for the DC network with a multiport converter

For complex networks with multiple subgrids formed by solid-state transformers, existing studies primarily focus on coordination within the networks in islanded mode, overlooking cooperation in grid-connected mode. To address this gap, this paper proposes a coordinated control scheme for the triple active bridge (TAB) converter in the grid-connected DC network. By establishing a droop relationship between the input power and the voltage difference, the TAB converter facilitates coordination between the utility grid and the DC network. The energy exchange with the utility grid is not only regulated by the TAB converter but also adjusted according to the utility grid state. So, the proposed scheme effectively facilitates coordination between the higher- and lower-level networks, strengthening system stability. Besides, the proposed scheme employs a unified control structure, which has power sharing and voltage regulation capabilities in grid-connected mode, as well as operating in islanded mode. This control structure enables the TAB converter to seamlessly transition across different operation modes, avoiding mode switching process and reducing the control complexity. Moreover, the proposed scheme is decentralized which negates the necessity for communication links, bolstering the system reliability. Lastly, the feasibility of the proposed scheme is analyzed in theory and validated by the hardware-in-loop tests.

Mixed Variable Parameter Energy Storage-Assisted Frequency Support Strategy

With the continuous increase in the installed capacity of new energy systems, the impact of power shocks on grid frequency is becoming more significant, seriously affecting the stability of the grid and thermal power units. For this reason, a mixed variable parameter energy storage-assisted frequency support control method is proposed. This method introduces an integral control mode based on the existing control mode and forms a co-ordinated control mode. The impact of the switching point of the mixed control mode is analyzed, and a new mode switching method is used. The model adjusts the frequency regulation parameters according to the different states of the grid frequency, making the frequency regulation more efficient. Finally, a frequency regulation model that integrates various improvement methods is built, and a 10 min continuous load disturbance is applied to compare and verify the frequency regulation performance of the model as a whole. The results indicate that the proposed control method can significantly improve the quality of grid frequency regulation, reduce the frequency deviation amplitude to 0.00096 p.u., reduce the participation time of thermal power units to 190.8393 s, and reduce the peak output to 0.1934 MW, demonstrating its engineering feasibility.