State Transition Behavior Research Articles

Experimental Study on the Self-Initiated Static-Dynamic State Transition Mechanism of Strain Rockburst

During the entire processes of rockburst catastrophe, the self-initiated static-dynamic state transition behaviour is a turning point in the development of strain rockburst from static deformation to dynamic failure. However, its dynamic process and triggering mechanism have not yet received sufficient attention and accurate revelation. This study focuses on the scientific issue, by designing experiment we have successfully achieved the physical simulation of rockburst under quasi-static displacement loading conditions. Then, the static-dynamic state transition process was studied on a millisecond time scale, and rockburst triggering mechanism was investigated from mechanical perspectives. Through experiment, the self-initiated elastic rebound dynamic behaviour of the surrounding rock is discovered and identified as the key to triggering rockburst. Mechanically, this behaviour directly causes an impact load on the burst rock, which can be considered the direct cause of rockburst.

Extreme Homogeneous and Heterogeneous Multistability in a Novel 5D Memristor-Based Chaotic System with Hidden Attractors

This paper proposes a novel five-dimensional (5D) memristor-based chaotic system by introducing a flux-controlled memristor into a 3D chaotic system with two stable equilibrium points, and increases the dimensionality utilizing the state feedback control method. The newly proposed memristor-based chaotic system has line equilibrium points, so the corresponding attractor belongs to a hidden attractor. By using typical nonlinear analysis tools, the complicated dynamical behaviors of the new system are explored, which reveals many interesting phenomena, including extreme homogeneous and heterogeneous multistabilities, hidden transient state and state transition behavior, and offset-boosting control. Meanwhile, the unstable periodic orbits embedded in the hidden chaotic attractor were calculated by the variational method, and the corresponding pruning rules were summarized. Furthermore, the analog and DSP circuit implementation illustrates the flexibility of the proposed memristic system. Finally, the active synchronization of the memristor-based chaotic system was investigated, demonstrating the important engineering application values of the new system.

Self-initiated static-dynamic state transition behavior and triggering mechanism of strain rockburst using three-dimensional discrete element method

The accurate understanding of rockburst mechanism poses a global challenge in the field of rock mechanics. Particularly for strain rockburst, achieving self-initiated static-dynamic state transition is a crucial step in the formation of catastrophic events. However, the state transition behavior and its impact on rockburst have not received sufficient attention, and are still poorly understood. Therefore, this study specifically focuses on the state transition behavior, aiming to investigate its abrupt transition process and formation mechanism, and triggering effects on rockburst. To facilitate the study, a novel burst rock-surrounding rock combined laboratory test model is proposed and its effectiveness is validated through experiment verification. Subsequently, corresponding numerical models are established using the three-dimensional (3D) discrete element method (DEM), enabling successful simulation of static brittle failure and rockbursts of varying intensities under quasi-static displacement loading conditions. Moreover, through secondary development, comprehensive recording of the mechanical and energy information pertaining to the combined specimen system and its subsystems is achieved. As a result of numerical investigation studies, the elastic rebound dynamic behavior of the surrounding rock was discovered and identified as the key factor triggering rockburst and controlling its intensity. The impact loading on the burst rock, induced by elastic rebound, directly initiates the dynamic processes of rockburst, serving as the direct cause. Additionally, the transient work and energy convergence towards the burst rock resulting from elastic rebound are recognized as the inherent cause of rockburst. Moreover, it has been observed that a larger extent of surrounding rock leads to a stronger elastic rebound, thereby directly contributing to a more intense rockburst. The findings can provide novel theoretical insights for the exploring of rockburst mechanism and the development of monitoring and prevention techniques.

Solution and dynamics analysis of fractal-fractional multi-scroll Chen chaotic system based on Adomain decomposition method

In recent years, newly proposed fractal-fractional calculus operators have been used to predict the chaotic behavior of some attractors, and the new operators can capture self-similarity in the studied chaotic attractors. The results of varying with fractal order and fractional order are interesting, however, the dynamics are barely analyzed in these studies, and the law of fractal order and fractional order on the system is not clear. In this paper, the fractal-fractional differential operators with inverse operator property are redefined in the Caputo sense, and a new numerical scheme is proposed based on the sixth-order Adomain decomposition method. Then the dynamics of the new multi-scroll Chen chaotic system and its three degradation modes are analyzed completely in the fractal-fractional sense. The influence of the change of fractal order and fractional order on the chaotic system is revealed. Finally, a new physical phenomenon of the fractal-fractional chaotic system is captured by observing the coexistence of multi-scroll and two-scroll chaotic attractors of the new system through a wood-grain-like attractor basin, as well as transient chaos, chaotic jumps, and complex state transition behaviors. It is shown that fractal-fractional multi-scroll Chen system has complex and specific dynamical behaviors.

Long-run analysis of a perturbed HIV/AIDS model with antiretroviral therapy and heavy-tailed increments performed by tempered stable Lévy jumps

The novelty of this article lies in providing a new framework for modeling the dynamics of HIV/AIDS infection under antiretroviral therapy (ART) which aims to reduce a person's viral load to an undetectable level. Since HIV/AIDS transmission can exhibit very tailed behavior (unpredictable jumps) due to the fact that the risk of spreading can vary greatly depending on the behavior and characteristics of individuals, we probe the effect of α-stable jumps on its asymptotic dynamics. Our proposed model is a compartmental step-wise formulation that takes the form of a system of Itô-Lévy differential equations with α-stable process. First, we check its well-posedness and we give the necessary assumptions needed for the analysis. Then, and based on a new approach, we prove two main asymptotic scenarios: extinction and stationary persistence of HIV/AIDS infection. The theoretical outcomes show that the kinetic behavior of our HIV/AIDS system is principally induced by certain underlying parameters, which are accurately correlated to the Lévy noise amplitudes. Finally, we reinforce our study with two numerical experiments to test the impact of the innovative mathematical techniques adopted to obtain the main results. Moreover, we numerically highlight the influence of α-stable jumps in epidemic state transition and dynamic behavior change.

Elucidating Transition State Behaviour from Mobility Data by Cascades of Markov Chains

With the ongoing trend towards digitisation, vast amounts of, often very fine-grained, data are being collected. The ultimate goal is to capture and understand the behaviour of a system, such as the traffic in a city. However, making sense of such data is not straightforward due to its high level of detail and complex dependencies in time and space. Exploring heuristic approaches is essential to arrive at data representations that enable better insights into the underlying system dynamics by zooming out from the detail. In this paper, a novel approach for representing and reasoning about traffic state transition behaviour via a multitude of parameterised Markov chains models, cleverly designed to fit in a cascade, is proposed. The benefits of working with a multitude of individual Markov chains are outlined and subsequently, it is illustrated how to combine them into daily transition graphs such that their graph representation can be exploited to extract insights about daily traffic behaviour. In addition, targeting context-specific studies, an alternative approach is introduced combining in a dynamic fashion a cascade of Markov chains covering longer and overlapping time windows. A recursive algorithm is conceived and validated allowing to exploit this cascade structure for computing state transition probabilities over time. The potential of the proposed approach for mining traffic state transitions is demonstrated on a use case derived from real-world data.

Multilevel Operation of Ferroelectric FET Memory Arrays Considering Current Percolation Paths Impacting Switching Behavior

This paper reports multi-level-cell (MLC) operation of ferroelectric FETs (FeFET) arranged in AND-connected memory arrays with a bit-error rate (BER) of 4% when writing a random data pattern. The FeFETs with HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> have been embedded in GlobalFoundries 28 nm bulk high-k metal gate (HKMG) technology and are based on a metal-ferroelectric-isolator-semiconductor (MFIS) stack. Due to the direct field influence of the ferroelectric layer onto the Si-channel current percolation paths (CPPs) dominate the state transition behavior. This results in device-to-device variation and contributes to the asymmetry in programming and erasing progression. For array operation, write schemes and state-preserving inhibit schemes are evaluated to cope with the influence of the CPPs. Finally, this enables us to take advantage of the MLC capabilities of FeFETs on the array level, further enhancing the storage density of the 1T memory cells. Robust retention is proven for the MLC states at 85°C as well as reliable rewritability of the memory array with changing input patterns.

A Special State Transition in the Blazar OT 081: Implication for the Unified State Transition Paradigm of Different-scale Black Hole Systems

Exploring the similar behavior of black hole systems with different scales will provide insight into the unified physical laws of black hole systems. Here, we report a special spectral state transition process in blazar OT 081, which is driven by a supermassive black hole. Based on the X-ray flux versus photon index distribution, stacked average X-ray spectra, L 2500Å − α ox parameters, and broadband spectral energy distributions, we conducted a pilot study on the spectral state transition for this blazar system. The analysis results suggest that the source transitions through a steady-state point from a strong corona, weak jet unsteady state to a weak corona, strong jet unsteady state. This state transition behavior is similar to that observed in the much smaller Galactic black hole binary systems, providing further observational evidence for the possible existence of a unified state transition paradigm for black hole systems with different scales.

Characterization of Single Length Cycle Two-Attractor Cellular Automata Using Next-State Rule Minterm Transition Diagram

Cellular automata (CAs) are simple mathematical models that are effectively being used to analyze and understand the behavior of complex systems. Researchers from a wide range of fields are interested in CAs due to their potential for representing a variety of physical, natural and real-world phenomena. Three-neighborhood one-dimensional CAs, a special class of CAs, have been utilized to develop various applications in the field of very large-scale integration (VLSI) design, error-correcting codes, test pattern generation, cryptography and others. A thorough analysis of a three-neighborhood cellular automaton (CA) with two states per cell is presented in this paper. A graph-based tool called the next-state rule minterm transition diagram (NSRTD) is presented for analyzing the state transition behavior of CAs with fixed points. A linear time mechanism has been proposed for synthesizing a special class of irreversible CAs referred to as single length cycle two-attractor CAs (TACAs), having only two fixed points.

Evidence for surface effects on the intermolecular interactions in Fe(II) spin crossover coordination polymers.

From X-ray absorption spectroscopy (XAS) and X-ray photoemission spectroscopy (XPS), it is evident that the spin state transition behavior of Fe(II) spin crossover coordination polymer crystallites at the surface differs from the bulk. A comparison of four different coordination polymers reveals that the observed surface properties may differ from bulk for a variety of reasons. There are Fe(II) spin crossover coordination polymers with either almost complete switching of the spin state at the surface or no switching at all. Oxidation, differences in surface packing, and changes in coordination could all contribute to making the surface very different from the bulk. Some Fe(II) spin crossover coordination polymers may be sufficiently photoactive so that X-ray spectroscopies cannot discern the spin state transition.

Modeling the modulus of bitumen/SBS composite at different temperatures based on kinetic models

Bitumen/styrene-butadiene-styrene (SBS) polymer composite material (also coded as polymer modified bitumen, PMB) is one of the most employed composite materials in the pavement industry. PMB is viscoelastic and exhibits temperature-dependent modulus. Abundant researches have investigated the influence of temperature on the PMB modulus, however few have attempted to establish a model to describe the direct relationship between the PMB modulus and the temperature. This paper aims to use a kinetic model for fiber reinforced composite to describe the inherent relationship between the PMB modulus and temperature. Furthermore, a modified model is proposed to find better fitting results specifically for PMB composite. Considering the fact that PMB has a much higher polydispersity, the modified model uses nonlinear least squares regression instead of the original Coats–Redfern method to determine the kinetic parameters (activation energy and pre-exponential factor). The determination of glassy state modulus and rubbery state modulus is also replaced by numerical optimization instead of visual inspection. The predicted modulus was compared with experimental results obtained by Dynamic Mechanical Analysis (DMA), and a good agreement was found. The method introduced by this study could be a promising approach to study the temperature-dependent properties and state transition behaviors of PMB composite.

Engineering attractive interaction in ZIF-based phase change materials for boosting electro- and photo- driven thermal energy storage

Metal organic frameworks contain abundant empty space for selectively absorbing phase change materials (PCM) molecules and sometimes chemically transformed. However, the strong attractive interaction between metal organic frameworks and PCM severely blocks sufficient crystalline-amorphous state transition of PCM. Herein, we proposed an attractive interaction engineering strategy on hierarchical zeolitic imidazolate frameworks (ZIF) based phase change materials (polyethylene glycol/carbon cloth@ZIF, PEG/CC@ZIF) for boosting crystalline-amorphous state transition behavior and electro-/photo- driven thermal performance. Carboxyl-modified CC scaffold regulates attractive interaction between ZIF and PEG, which enhances energy storage capacity of the phase change composite. Moreover, ZIF nanoflakes deposited on the surface of CC reduce the convective heat loss at the solid–gas interface, and CC scaffold facilitates electron transportation and photon penetration, thus significantly enhancing electro- and photo- driven thermal energy storage. Furthermore, ZIF-induced chain effect between PEG and CC enhances the mechanical properties of PEG/CC@ZIF. Notably, commercially available transition metal oxide photocatalyst can be uniformly sprayed on the surface of PEG/CC@ZIF through coordination chemical engineering for multi-functional phase change composite.

Magnetic Field Perturbations to a Soft X-ray-Activated Fe (II) Molecular Spin State Transition

The X-ray-induced spin crossover transition of an Fe (II) molecular thin film in the presence and absence of a magnetic field has been investigated. The thermal activation energy barrier in the soft X-ray activation of the spin crossover transition for [Fe{H2B(pz)2}2(bipy)] molecular thin films is reduced in the presence of an applied magnetic field, as measured through X-ray absorption spectroscopy at various temperatures. The influence of a 1.8 T magnetic field is sufficient to cause deviations from the expected exponential spin state transition behavior which is measured in the field free case. We find that orbital moment diminishes with increasing temperature, relative to the spin moment in the vicinity of room temperature.

Chain dynamics evolution of ethylene‐propylene‐diene monomer in response to hot humid and salt fog environment

AbstractThis work is dedicated to the mechanism underlying the influence of the harsh environment that may cause accelerated aging (high temperature, humidity, and salt spray) on the static and dynamics characteristics of ethylene‐propylene‐diene monomer (EPDM) copolymer. A molecular dynamics simulation was employed to provide an insight into the effects of the hot humid and salt fog environment on the micro and macroscopic properties. First, evidence shows that the Tg obtained by fitting mean square displacement does not rely on the selection of the equilibrium time. Second, radial distribution function, chain configuration, and nonbonding interaction were analyzed and it is inferred that the ambient humidity and temperature show a significant synergy on the EPDM system, which is attributed to the aggregation state transition and diffusion behavior of partial water at high temperatures. Finally, water and salt were considered as two factors to explore the influence on the Tg and the mobility of the molecular chain. It is concluded that the existence of water molecules significantly affects the chain dynamic behavior of EPDM, while salt is not regarded as an influencing factor. In general, our simulated work provides some insights and guidance for the durability of EPDM when used in harsh environments.

Multiplicity of thermodynamic states of van der Waals gas in nanobubbles

The gas-containing nanobubbles have attracted extensive attention due to their remarkable properties and extensive application potential. However, a number of fundamental aspects of nanobubbles, including thermodynamic states for the confined gas, remain still unclear. Here we theoretically demonstrate that the van der Waals (vdW) gases confined in nanobubbles exhibit a unique thermodynamic state of remarkably deviating from the bulk gas phase, and the state transition behavior due to the size-dependent Laplace pressure. In general, the vdW gas inside nanobubbles present multiple stable or transient states, where 0–2 states are for supercritical gas and 0–4 for subcritical gas. Our further analysis based on Rayleigh–Plesset equation and free energy determination indicates that the gas states in nanobubbles exhibits different levels of stability, from which the coexistence of multiple bubble states and microphase equilibrium between droplets and bubbles are predicted. This work provides insight to understand the thermodynamic states appeared for gas in nanobubbles.

Discovery of State Transition Behaviors in PSR J1124–5916

Abstract With the 12 year long observations by Fermi-LAT, we discover two pairs of spin-down state transitions of PSR J1124–5916, making it the second young pulsar detected to have such behaviors. PSR J1124–5916 shows mainly two states according to its spin-down rate evolution, the normal spin-down state and the low spin-down state. In about 80% of the observation time, the pulsar is in the normal spin-down state, in which the spin-down rate decreases linearly and gives a braking index of 1.98 ± 0.04. The two transitions to the low spin-down state are in MJD 55183–55803 and MJD 56114–56398, respectively, with fractional amplitudes both ∼0.4%. No significant difference between the γ-ray profiles of the two spin-down states is detected, which is similar to PSR B0540–69, the other young pulsar with state transition detected.

Directly Printed Hollow Connectors for Microfluidic Interconnection with UV-Assisted Coaxial 3D Printing

Effective and reliable interconnections are crucial for microfluidics to connect with the macro world. Current microfluidic interfaces are still bulky, expensive, or with issues of clogging and material limitation. In this study, a novel ultraviolet (UV)-assisted coaxial three-dimensional (3D) printing approach was proposed to fabricate hollow microfluidic connectors with advantages of rapid prototyping, fixture-free, and materials compatible. An assembled coaxial nozzle was designed to enable co-flow extrusion, where the inner flow (water) served as the sacrificial layer and the outer flow (adhesive) was cured for shell formation. Furthermore, a converged UV-LED light source was attached to the coaxial nozzle for UV curing of adhesives. UV rheological characterizations were performed to study the UV curing kinematics, and the gelation time was employed to describe the state transition behaviors of UV curable adhesives used in the study. To explore requirements for successful hollow connectors direct printing, processing criteria such as co-flow regime and pre-cure time were investigated. The hollow connectors with an inner channel diameter of ~150 μ m and a height of 5 mm were successfully printed on polymethyl methacrylate (PMMA) and glass substrate. The integration feasibility of the proposed method was also demonstrated by the presented microfluidic device with printed hollow connectors.

A cellular automata guided two level obfuscation of Finite-State-Machine for IP protection

A popular countermeasure against IP piracy is to obfuscate the Finite State Machine (FSM) which is assumed to be the heart of a digital system. Most of the existing FSM obfuscation strategies rely on additionally introduced set of obfuscation mode state-transitions to protect the original state-transitions of the FSM. Although these methods assume that it is difficult to extract the FSM behavior from the flattened gate-level netlist, some recent reverse engineering attacks could successfully break the defense of these schemes. The capability of differentiating obfuscation mode state-transitions from normal mode state-transitions makes these attacks powerful. As a countermeasure against these attacks, we propose a new strategy that offers a key-based obfuscation to each state-transition of the FSM. We use a special class of non-group additive cellular automata (CA), called D1 ∗ CA, and it's counterpart D1∗CAdual to obfuscate each state-transition of the FSM. Each state-transition has its own customized key, which must be configured correctly in order to get correct state-transition behavior from the synthesized FSM. A second layer of protection to the state-transition logic enhances the security of the proposed scheme. An in-depth security analysis of the proposed easily testable key-controlled FSM synthesis scheme demonstrates its ability to thwart the majority of the state-of-the-art attacks, such as FSM reverse engineering, SAT, and circuit unrolling attacks. Thus, the proposed scheme can be used for IP protection of the digital designs. Experimentations on various IWLS′93 benchmark FSM designs show that the average area, power, and delay overheads our proposed multi-bit key-based obfuscated FSM design are 56.43%, 6.87%, and 23.41% while considering the FSMs as standalone circuits. However, experimentation on the Amber23 processor core shows these overheads drastically reduce (reported area, power, and delay overheads values are 0.0025%, 0.44%, and 0%, respectively) while compared with respect to the entire design.

A novel automata and neural network based fault diagnosis system for PLC controlled manufacturing systems

The Fault and Anomaly Detection and Isolation (FADI) in Programmable Logic Controller (PLC) controlled systems is an important and challenging problem. In this paper, we present an automated tool, called the Manufacturing Process Failure Diagnosis Tool (MPFDT) that can detect and isolate the faults and anomalies in the PLC controlled manufacturing systems effectively. MPFDT utilizes two independent knowledge-based process behaviour models of the manufacturing system to satisfy the FADI purpose. The fundamental idea is to detect the inconsistencies between the modelled and the observed manufacturing process behaviour. The first model is a Deterministic Finite-state Automaton (DFA) based model of the PLC control process that is used to determine whether the observed state transition behaviour of the PLC control process is consistent with the modelled state transition behaviour or not. The second model is basically a set of Artificial Neural Network (ANN) based one-class classifiers that are used to identify whether any significant difference exist between the observed and the reference electrical power consumption profile of the manufacturing system or not. The experimental results show that the FADI accuracy rate of the proposed tool is very high (more than 98%).

Matrix approach to simplification of finite state machines using semi‐tensor product of matrices

AbstractIn this paper, we use a new mathematical tool, semi‐tensor product of matrices, to investigate the problem of simplification of finite state machines (FSMs) in a mathematical manner. First, based on the dynamic equations of state transition and output behavior which are developed recently, an algebraic criterion of k‐difference states is established. Second, using the criterion, a scheme is designed to construct the incompatible graphs of FSMs. Third, with the incompatible graphs and the method of searching internally stable sets of graphs proposed by the authors, a solution is proposed to obtain all of the compatible state set (CSS) of FSMs. Then, with the aid of the CSS, we investigate three kinds of structures of state space of FSMs, including compatible cover of state set (CCSS), representative set of state set (RSSS), and minimum representative set of state set (MRSSS); necessary and sufficient conditions are proposed to formulate the three kinds of structures. Finally, examples are given to exemplify minimum realizations of FSMs by these conditions.