Switching Model Research Articles

Does internet use drive rural household savings? Evidence from 7825 farmer households in rural China

Based on the 7825 farmer households from the 2016 China Labor Dynamic Survey Database (CLDS), this study employs the Tobit model and endogenous switching model to empirically investigate the impact of Internet use on rural household savings. This study finds that: (1) Internet use in rural areas significantly promotes rural household savings. (2) Farmers with Internet use and close to the bank, may have higher saving rates than farmers with Internet use and far from the bank. (3) Rural household savings are also closely associated with the characteristics of the household head, household members, and the geographic location of the village.

Modeling the conduction mechanisms of intrinsic multi-level states in HfOx-based resistive random access memory

Multi-level cell storage technology based on resistive random access memory (RRAM) with multi-level state characteristics is more attractive in achieving low-cost ultra-high-density nonvolatile memory. Although a large number of literatures have reported the multi-level state characteristics of RRAM, so far there is no unified model that can well explain the intrinsic reasons for the existence of intermediate resistance state (IRS) and the switching mechanism between different resistance states. Multi-level state characteristics are observed by I–V characteristic measurements on RRAM with TiN/HfOx/barrier layer/TiN stacks fabricated using a commercialized 28 nm CMOS process. Compared to other published resistive switching models, the proposed model based on trap-assisted tunneling is more consistent with the measured. The model can reproduce the multi-level state characteristics based on the mechanism that interaction between defects and oxygen vacancies at the interface of HfOx and TiN electrode, resulting in the formation of multiple weak conductive filaments. Furthermore, the wide spread of high resistance state (HRS) and the switching between HRS and IRS are determined by the distance of tunneling gap. As HfOx-based RRAM will soon be commercialized, it is becoming very urgent to clarify the switching mechanisms of multi-level state characteristics and propose a universal model. Consequently, this work satisfied the current demand and significantly advanced the understanding and development of commercialized, cost-effective, high-density multi-bit HfOx-based RRAM technology.

A switching MPC-based power management strategy for DC microgrids with SOC consistency and energy loss

The DC microgrids equipped with photovoltaic and energy storage systems have increasingly been applied to unmanned vehicles, and energy management is attracted much more attention. In this work, a power management strategy based on switching model predictive control is proposed to tackle energy loss and inconsistency of energy storage systems. The dynamic characteristic of the battery are fully addressed, and the non-affine equation constraints are dealt with by the iterative approximation method. The proposed strategy balances energy loss and state-of-charge consistency of the energy storage system and can operate when future environmental information is unavailable. Finally, comparative examples with existing schemes verify the effectiveness of the proposed strategy.

Reduced sensor based single stage charger with four quadrant capabilities using predictive control

Single stage battery chargers eliminate the DC link capacitor stage between two stage power conversion. In this work, a reduced sensor based four quadrant charger with single stage power conversion is realized with AC–DC matrix converter topology. Although, a small capacitor filter on DC side is used in this configuration, it is only required to supply or absorb high frequency ripple component of the battery current, to prevent the battery from being damaged. The grid current estimation is done using the converter switching model and AC side filter model, leading to the elimination of grid current sensor. The simple model predictive control used here in conjunction with instantaneous reactive power theory, avoids the use of any proportional integral controller, thus making the control scheme simpler. The single stage design increases power density, and the charger’s dependability is increased by the absence of a large electrolytic capacitor. While the battery charges and receives power from the grid, the AC–DC matrix converter used here, performs a voltage bucking function. The simulation results and experimental findings from a lab-developed hardware prototype are used to validate the design and control of the proposed charger.

Determinants of the European Sovereign Debt Crisis: Application of Logit, Panel Markov Regime Switching Model and Self Organizing Maps.

The study aims to empirically identify the determinants of the debt crisis that occurred within the framework of 15 core EU member countries (EU-15). Contrary to previous empirical studies that tend to use event-based crisis indicators, our study develops a continuous fiscal stress index to identify the debt crises in the EU-15 and employs three different estimation techniques, namely self-organizing map, multivariate logit and panel Markov regime switching models. Our estimation results show first that the study correctly identifies the time and the length of the debt crisis in each EU-15-member country. Empirical results then indicate, via three different models, that the debt crisis in the EU-15 is the consequence of deterioration of both financial and macroeconomic variables such as nonperforming loans over total loans, GDP growth, unemployment rates, primary balance over GDP, and cyclically adjusted balance over GDP. Furthermore, variables measuring governance quality, such as voice and accountability, regulatory quality, and government effectiveness, also play a significant role in the emergence and the duration of the debt crisis in the EU-15.

Compact multifilament model of resistive switching metal-oxide memristor

A fairly simple compact circuit multifilament resistive switching model of a metal-oxide memristor with controlled multilevel conductance tuning is presented, which is in demand for self-training of large arrays of memristor synapses and information processing using them. A good agreement between the calculated and measured volt-ampere characteristics and the pulse-time dependent plasticity curve is shown.

Effect of PIN Diode Integration on Patch Antennas for Frequency Reconfigurable Antenna Applications

PIN diodes are commonly used to design reconfigurable antennas owing to their sufficient isolation, lower cost, and ease of fabrication. This study aims to explore the effect of biasing conditions of a PIN diode radio frequency (RF) switch on a frequency-reconfigurable antenna. This approach investigates the contribution of the forward diode current and the reversed biased voltage on the shift in the operating band, the impedance matching, and the radiation efficiency of a reconfigurable antenna. The benefits and drawbacks of different approaches to modeling PIN diode RF switches are demonstrated on Ansys electromagnetic switch. The result shows a significant match between simulated and measured operating bands, impedance matching, and radiation efficiency. The proposed RF switch model can be used as a practical simulation model for implementing various reconfigurable microwave components.

On the Existence of Negative Capacitance: Examining Ferroelectric-Dielectric Stack Experiments Using the NLS and LK Models

The Landau–Khalatnikov (LK) model of ferroelectric switching includes an inherent region of negative capacitance (NC) in its lossless charge versus voltage description and allows the possibility of stabilization of the ferroelectric in this region to achieve quasi-static NC (QSNC). On the other hand, the nucleation-limited switching (NLS) model, which is another model used to describe ferroelectric switching, precludes QSNC and offers an alternative explanation for the appearance of an NC region in recent voltage-pulse experiments performed on ferroelectric-dielectric (FE-DE) stacks. As such, we investigate such experiments that probe the existence of an NC region using both the LK and NLS models. While the LK model can reproduce all experimental results seen in prior literature, we find that the NLS model is incapable of properly reproducing results under a multitude of investigation metrics. Hence, we conclude that the use of the NLS model to exclude the existence of QSNC is problematic.

Analyzing the Impact of Foreign Capital Inflows and Political Economy on Economic Growth: An Application of Regime Switching Model

The goal of this study is to use the Markov Regime Model (MSM) to evaluate the impact of three important FCIs and the political economy on Pakistan’s economic growth. The current research used quarterly data from 2000 to 2020. The empirical results demonstrate that dictatorship contributes favorably to the high and low growth regime of the economy, while election time contributes positively to the expansion period and adversely in recession times of the economy. Results confirmed that external debt has a strong negative influence on economic growth in both the high and low-growth regimes. Remittances, FDI, and growth, on the other hand, have a positive and substantial link with economic growth. This research suggested that effective fiscal and monetary policies, as well as a suitable political environment, should be provided so that foreign investors would be enticed to invest in Pakistan.

Research on the Reliability Test and Life Assessment Methods of Relays Used in Circuit Breaker Operating Mechanism

As one of the key components of the circuit breaker operating mechanism, the relay can experience performance degradation due to harsh environmental factors, such as salt spray, during operation, which can ultimately affect the normal operation of the circuit breaker and threaten the safe and stable operation of the power system. To effectively evaluate the condition of the relay operating in salt spray environments over the long term, this study conducted accelerated aging experiments on a certain model of auxiliary switch under salt spray conditions using an existing test platform. The relay’s pull-in voltage, release voltage, pull-in time, and release time were analyzed as characteristic parameters affected by salt spray. The results showed that the intrusion of salt spray caused a decline in the coil performance of the relay, which required higher voltage to provide the electromagnetic force needed for operation, leading to an increase in operating voltage. On the other hand, coil degradation also caused a decrease in the electromagnetic force generated by the step voltage, resulting in a slower operating time. Subsequently, a Genetic Algorithm_Back Propagation Neural Network GA_BP) algorithm model suitable for identifying the relay status in this study was established. After optimization by a Genetic Algorithm Neural Network (GA), the recognition accuracy increased from 78.6% to 91.8%, which showed significant improvement. By clarifying the changes in the characteristic parameters of the relay in a salt spray environment and relying on experimental data, this study established a relevant state recognition model. The research results have important engineering application value for understanding the relay operating status of the circuit breaker operating mechanism in salt spray environments, conducting circuit breaker operating mechanism relay life prediction, and preventing circuit breaker operating mechanism failures.

Conformational switching and flexibility in cobalamin-dependent methionine synthase studied by small-angle X-ray scattering and cryoelectron microscopy

Cobalamin-dependent methionine synthase (MetH) catalyzes the synthesis of methionine from homocysteine and 5-methyltetrahydrofolate (CH3-H4folate) using the unique chemistry of its cofactor. In doing so, MetH links the cycling of S-adenosylmethionine with the folate cycle in one-carbon metabolism. Extensive biochemical and structural studies on Escherichia coliMetH have shown that this flexible, multidomain enzyme adopts two major conformations to prevent a futile cycle of methionine production and consumption. However, as MetH is highly dynamic as well as both a photosensitive and oxygen-sensitive metalloenzyme, it poses special challenges for structural studies, and existing structures have necessarily come from a "divide and conquer" approach. In this study, we investigate E. coli MetH and a thermophilic homolog from Thermus filiformis using small-angle X-ray scattering (SAXS), single-particle cryoelectron microscopy (cryo-EM), and extensive analysis of the AlphaFold2 database to present a structural description of the full-length MetH in its entirety. Using SAXS, we describe a common resting-state conformation shared by both active and inactive oxidation states of MetH and the roles of CH3-H4folate and flavodoxin in initiating turnover and reactivation. By combining SAXS with a 3.6-Å cryo-EM structure of the T. filiformis MetH, we show that the resting-state conformation consists of a stable arrangement of the catalytic domains that is linked to a highly mobile reactivation domain. Finally, by combining AlphaFold2-guided sequence analysis and our experimental findings, we propose a general model for functional switching in MetH.

ВЛИЯНИЕ ЧАСТОТЫ ПЕРЕМЕННОГО ПОЛЯ НА ЭЛЕКТРОФИЗИЧЕСКИЕ СВОЙСТВА ПОЛИМЕРНЫХ ПЛЕНОК

The results of an experimental study of the frequency dependences of the impedance of metal-polymer-metal sandwich structures for different thicknesses of the polymer layer are presented. The voltage characteristics of the samples in various frequency ranges were measured. The general view of the amplitude-frequency characteristics graphs for all film thicknesses is well described by the theoretical model of the sequential RC circuit. On all graphs, you can notice the presence of a cutoff frequency, which can be interpreted as the beginning of the RC filter. However, there are also significant deviations from the theoretical characteristics. It is established that with a polymer layer thickness of 80 nm in the frequency range At 10-40 Hz, an abnormal decrease in impedance is observed, corresponding to an increase in current at the volt-ampere characteristics. The resulting charge instability is considered as a consequence of the volume-charge polarization, which, in turn, is due to the specifics of polymer-polymer interfaces that arise during the formation of the supramolecular structure of the polymer. The results of the work are interpreted within the framework of the resistive switching model, which assumes that in the case of submicron polymer films used in the metalpolymer-metal system, resistive switching is possible as a result of the sequential transformation of the energy electronic subsystem of the polymer film under the action of charge injection from the electrodes.

Evaluating the impact of productive safety net program on rural household food security achievement: Endogenous switching regression modeling approach

The Ethiopian government, together with other organizational partners, developed the Rural Productive Safety Net Program (PSNP) to combat food insecurity. Therefore, this article aimed to examine the impact of a rural PSNP on household food security in the market district. By the probability sampling technique, 380 sample households and two rural PSNP technicians used as the primary data source, while secondary data were collected from the national report. The analysis was carried out with the help of descriptive analysis and econometric models. The study used Endogenous Switching Model (ESM) to analyze and examine the impacts of a rural PSNP on food security and identify factors that affect household participation in rural PSNP. Ten explanatory variables were included in the model to identify the determinant variable, of which seven are significant. The significant variable found to determine households’ participation in rural PSNP is age, livestock unit, labor force, cultivated land, off-farm income, and credit access by a level of confidence of 5% and 1%, respectively. The study findings showed that participation in rural PSNP only increases current consumption smoothing rather than future consumption, after graduating member households turn back into their previous living standards. Currently, food insecurity is one of the main challenges in the study area that requires immediate intervention to alleviate the problem. The PSNP is one of the integrated programs with the aim of helping food-insecure rural households become food-secure ones. Based on the finding, the study recommends that the program cash transfer should be increased and complementary community investment should be introduced. The limitation of some targeting criteria is an observed problem of the program in the study area. Due to certain criteria, poor households were excluded. Therefore, an adjustment of the criteria that had been taken to exclude poor households is necessary.

Intra-hour photovoltaic forecasting through a time-varying Markov switching model

This work presents a Markov switching model with a time-varying transition matrix to forecast intra-hour photovoltaic (PV) power output, aiming at providing forecasting flexibility. First, the proposed methodology captures images of the sky employing a self-made, low-cost all-sky imager. Second, the goal is to limit exposure problems in those images via the exposure fusion technique. Third, the proposed algorithm identifies groups of pixels forming clouds through a super paramagnetic clustering algorithm. Finally, we model the problem with a homogeneous Poisson process and forecast the cloud location and the shadowed area on a PV plant for the coming minutes. The shadowed area together with meteorological data are the inputs to this model. In the case study, our approach shows better performance than the persistence method, in particular for changing cloud conditions.

Semi-automated bathymetry using Sentinel-2 for coastal monitoring in the Western Mediterranean

Nearshore bathymetry is one of the main parameters used in coastal studies. However, regular and continuous bathymetries are scarce due to the difficulty of continuous data collection using traditional surveys. Remote sensing offers an attractive alternative to conventional collection methods for acquiring freely available, reliable, and frequent high-resolution data from space missions, such as the European Union's Copernicus programme Sentinel-2A/B satellites, which are increasingly demonstrating their potential to derive bathymetric information. Consequently, satellite-derived bathymetry (SDB) is being used more regularly because of its low cost and high efficiency. In this study, we apply a log-transformed band ratio SDB model in the Western Mediterranean Sea (Mallorca Island, Spain). This model has been widely used in the Caribbean and along the U.S. coast, among other sites, with outstanding results in heterogeneous environments. The SDB model consists of an automatic multi-scene approach applied over several images corrected by a robust atmospheric correction model (ACOLITE), a switching model, and a procedure to remove pixels from optically deep waters. We retrieve depths up to 14 m with a mean bias of 0.02 m and a median absolute error of 0.71 m compared with multibeam echo-sounder (MBES) data. The outcomes of this study confirm the effectiveness of the multi-scene approach to automatically correct the imagery to derive accurate depths and characterize erosional and accretion patterns annually. Furthermore, it highlights the benefit of the switching model to take advantage of the spectral sensitivity of different multi-band ratio approaches. This study will provide the scientific community with substantial knowledge and improved SDB techniques to consolidate the understanding of nearshore processes in such a relevant ecosystem as the Mediterranean Sea.

Resistive Switching: Physics, Devices and Applications

Resistive Switching: Physics, Devices and Applications

A Study of Trade Strategies Based on the Markov Regime Switching Model

Market traders often buy and sell stocks to maximize their total return. For each purchase and sale, there is often a return commission. Having trading technology plays an important role in quantitative trading. In this paper, we first use the XGBoost model to learn the historical price fluctuation data of gold and bitcoin, and the prediction accuracy R2 is between 0.998 and 0.999, which is a good fit. Then LT algorithm and PS algorithm are used to identify the rules, the Markov regime switching model is used to determine the bear and bull market, and finally, the DQN model is used to plan the trading strategy and add a machine learning algorithm to it to optimize the strategy to get the initial $1000 in the future investment strategy.

Is energy transition possible for oil-producing nations? Probing the case of a developing economy

An expected decline in oil revenue and a complicated global energy market present significant concerns about oil-producing countries’ intentions to move away from fossil fuels. Understanding the dynamics of these concerns, particularly in light of potential energy transitions, is crucial for future energy supply and sustainable energy discussion. Given the scarcity of research on the issue, this study examined whether an implied shift from fossil fuels to a cleaner energy state is possible for Ghana, a small oil-producing economy in sub-Saharan Africa. A two-state Markov Switching Model (MSM) was applied to a dataset covering 1980–2019. Results based on a multivariate state-dependent regression technique were documented as follows: First, the probability of transitioning from a nonrenewable energy state to a renewable energy state is 76.5%. Second, there is 80.2% chance of remaining in a renewable energy state for five years. Third, fossil fuel production undermines cleaner energy development as 1% growth in nonrenewable energy causes a 0.20% decline in renewable energy generation. Finally, trade openness and foreign direct investment promote cleaner energy growth. The study concluded that Ghana’s economy has a greater chance of transitioning from fossil fuels and an equally higher chance of realizing a cleaner energy state, despite a declining policy support for renewable energy development.

An Optimized Electric Propulsion System for Hyperloop Applications

In this paper, an advanced electric propulsion system (EPS) is designed for an ultra-fast electric train. The proposed system consists of a slotless dual-sided linear synchronous motor (DSLSM) and a three-step track powering topology. A multi-objective optimization workflow based on a reduced-order model of DSLSM is used to optimize the permanent magnets (PMs) and the winding dimensions to maximize the thrust force density and efficiency. The optimized model is validated using the finite element analysis (FEA). Then, a new fault-tolerant control algorithm is proposed for the optimized DSLSM fixing the mover in the center of the DSLSM under any airgap disturbance. Finally, a high-fidelity switching model of the complete EPS is developed. The performance of the proposed EPS is verified using a real-time hardware-in-the-loop (HIL) simulator under normal and faulty conditions.

Opposite thermal-stimuli fluorescent behavior induced by π-bridge in two carbazole derivatives for high-level information encryption

Organic luminophores that exhibit emission ON-OFF switching under thermal stimulus are prominent candidates for developing high-level information encryption. Herein, the rationally controlled luminescence ON-OFF switching behavior of two carbazole derivatives with identical acceptor by tailoring the π-bridge are demonstrated. CPDI with phenyl π-unit showed aggregation induced emission (AIE) but thermally stimulated emission turn-off, while CTDI with thienyl as π-unit exhibited a totally different aggregation caused quenching (ACQ) and thermally stimulated emission turn-on in the solid-state. Structural characterizations revealed that the difference was derived from the opposite effect that form intermolecular π-π interactions after heating treatment. Based on their opposite thermally stimulated ON-OFF and OFF-ON luminescence switching model, fourth-level information encryption application was achieved.