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An efficient simulation algorithm using an algebra of transients for gate circuits was proposed by Brzozowski and Ésik. This algorithm seems capable of predicting all the signal changes that can occur in a circuit under worst-case delay conditions. We verify this claim by comparing simulation with binary analysis. For any feedback-free circuit consisting of one- and two-input gates, we prove that all signal changes predicted by simulation occur in binary analysis, provided that wire delays are taken into account. Two types of finite automata play an important role in our proof.

Transient simulation of a gate circuit is an efficient method of counting signal changes occurring during a transition of the circuit. It is known that this simulation covers the results of classical binary analysis, in the sense that all signal changes appearing in binary analysis are also predicted by the simulation. For feedback-free circuits of 1- and 2-input gates, it had been shown that the converse also holds, if wire delays are taken into account. In this paper we generalize this result. First, we prove that, for any feedback-free circuit N of arbitrary gates, there exists an expanded circuit, constructed by adding a number of delays to each wire of N, such that binary analysis of covers transient simulation of N. For this result, the number of delays added to a wire is obtained from the transient simulation. Our second result involves adding only one delay per wire, which leads to the singular circuit of N. This result is restricted to circuits consisting only of gates realizing functions from the set , functions obtained by complementing any number of inputs and/or the output of a function from , and FORKS. The numbers of inputs of the AND, OR and XOR gates are arbitrary, and all functions of two variables are included. We show that binary analysis of such a circuit covers transient simulation of N. We also show that this result cannot be extended to arbitrary gates, if we allow only a constant number of delays per wire.

Transient algebra is a multi-valued algebra for hazard detection in gate circuits. Sequences of alternating 0's and 1's, called transients, represent signal values, and gates are modeled by extensions of boolean functions to transients. Formulas for computing the output transient of a gate from the input transients are known for NOT, AND, OR and XOR gates and their complements, but, in general, even the problem of deciding whether the length of the output transient exceeds a given bound is NP-complete. We propose a method of evaluating extensions of general boolean functions. We study a class of functions for which, instead of evaluating the extensions on a given set of transients, it is possible to get the same values by using transients derived from the given ones, but having length at most 3. We prove that all functions of three variables, as well as certain other functions, have this property, and can be efficiently evaluated.

In this paper, we investigate the complexity of computing the detector, constructor and lexicographic constructor functions for a given language. The following classes of languages will be considered: (1) context-free languages, (2) regular sets, (3) languages accepted by one-way nondeterministic auxiliary pushdown automata, (4) languages accepted by one-way nondeterministic logspace-bounded Turing machines, (5) two-way deterministic pushdown automaton languages, (6) languages accepted by uniform families of constant-depth polynomial-size Boolean circuits, and (7) languages accepted by multihead finite automata. We show that for the classes (1)–(4), efficient detectors, constructors and lexicographic constructors exist, whereas for (5)– (7) polynomial-time computable detectors, constructors and lexicographic constructors exist iff there are no sparse sets in NP−P (or equivalently, E=NE). Our results provide sharp boundaries between classes of languages which have efficient detectors, constructors and classes of languages for which efficient detectors and constructors do not appear to exist.

We report a transient circuit model of Pt/TiO₂(40nm)/Pt memristor that accurately represents the underlying switching mechanism and can be extended to any other material platforms. The analysis is based on the analytic formulation of dynamical characteristics. The transient circuit model is simulated in Cadence using HSPICE. Rise time and fall times of the 40 nm TiO₂ memristor were calculated to be 11.4 ps and 11.6 ps, respectively. The settling time during ON and OFF switching was determined to be 1.04 ns and 0.78 ns, respectively.

Based on the property of a passive system, the essential conditions under which a hyperchaotic Lorenz system could be equivalent to a passive system via smooth state feedback are derived, making the minimum phase hyperchaotic Lorenz system globally asymptotically stabilized at zero and at any desired equilibrium points. The results of simulation on Matlab and the circuit experiment on EWB confirm the effectiveness of the proposed hyperchaos control method.

In this paper, a new four-dimensional (4D) chaotic system with two cubic nonlinear terms is proposed. The most striking feature is that the new system can exhibit completely symmetric coexisting bifurcation behaviors and four symmetric coexisting attractors with the same Lyapunov exponents in all parameter ranges of the system when taking different initial states. Interestingly, these symmetric coexisting attractors can be considered as unusual symmetrical rotational coexisting attractors, which is a very fascinating phenomenon. Furthermore, by using a memristor to replace the coupling resistor of the new system, an interesting 4D memristive hyperchaotic system with one unstable origin is constructed. Of particular surprise is that it can exhibit four groups of extreme multistability phenomenon of infinitely many coexisting attractors of symmetric distribution about the origin. By using phase portraits, Lyapunov exponent spectra, and coexisting bifurcation diagrams, the dynamics of the two systems are fully analyzed and investigated. Finally, the electronic circuit model of the new system is designed for verifying the feasibility of the new chaotic system.

We report the experimental implementation of the most fundamental NOR gate with a chaotic Chua's circuit by a simple threshold mechanism. This provides a proof-of-principle experiment to demonstrate the universal computing capability of chaotic circuits in continuous time systems.

A novel four-dimensional continuous-time autonomous hyperchaotic system which has no equilibrium is proposed in this paper. By starting from a third-order chaotic system and introducing a further variable performing state feedback, a four-dimensional system exhibiting hyperchaos is obtained. The basic dynamical properties of this system are investigated, such as equilibria and stability, Lyapunov exponent spectrum, and bifurcation diagrams. Furthermore, synchronization via diffusive coupling or control has been addressed. In the latter, parameter identification and synchronization are performed simultaneously. The circuit realization and experimental results are also presented.

The memristor is referred to as the fourth fundamental passive circuit element of which inherent nonlinear properties offer to construct the chaos circuits. In this paper, a flux-controlled memristor circuit is developed, and then a van der Pol oscillator is implemented based on this new memristor circuit. The stability of the circuit, the occurring conditions of Hopf bifurcation and limit circle of the self-excited oscillation are analyzed; meanwhile, under the condition of the circuit with an external exciting source, the circuit exhibits a complicated nonlinear dynamic behavior, and chaos occurs within a certain parameter set. The memristor based van der Pol oscillator, furthermore, has been created by an analog circuit utilizing active elements, and there is a good agreement between the circuit responses and numerical simulations of the van der Pol equation. In the consequence, a new approach has been proposed to generate chaos within a nonautonomous circuit system.

Although chaotic systems with hidden attractors have been discovered recently, there are few investigations about relationships among them. This brief work introduces a novel chaotic system with only one stable equilibrium that is constructed by adding a tiny perturbation into a known chaotic flow having hidden attractors with a line equilibrium.

Recent evidence suggests that a system with only stable equilibria can generate chaotic behavior. In this work, we study a chaotic system with two stable equilibrium points. The dynamics of the system is investigated via phase portrait, bifurcation diagram and Lyapunov exponents. The feasibility of the system is introducing its electronic realization. Moreover, the chaotic system is used in Symmetric Chaos Shift Keying (SCSK) and Chaotic ON-OFF Keying (COOK) modulated communication designs for secure communication. It is determined that the SCSK modulated communication system implemented with the chaotic system is more successful than COOK modulation for secure communication.

A new chaotic system having variable equilibrium is introduced in this paper. The presence of an infinite number of equilibrium points, a stable equilibrium, and no-equilibrium is observed in the system. Interestingly, this system is classified as a rare system with hidden attractors from the view point of computation. Complex dynamical behavior and a circuital implementation of the new system have been investigated in our work.

This paper reports some hidden hyperchaotic attractors and complex dynamics in a new five-dimensional (5D) system with only two nonlinear terms. The system is generated by adding two linear controllers to an unusual 3D autonomous quadratic chaotic system with two stable node-foci. In particular, the hyperchaotic system without equilibrium or with only one stable equilibrium can generate two kinds of hidden hyperchaotic attractors with three positive Lyapunov exponents. Numerical methods not only verify the existence of such attractors and hyperchaotic attractors, but also show the dynamical evolution of this system. The 5D system has self-excited attractors and two types of hidden attractors with the change of its parameter. The parameter switching algorithm is further utilized to numerically approximate the attractor. Specifically, the hidden hyperchaotic attractor can be approximated by switching between two self-excited chaotic attractors. Finally, the circuit realization results are consistent with the numerical results.

Speech Emotion Recognition (SER) is a challenging task characterized by the diversity and complexity of emotional expression. Due to its powerful feature extraction capabilities, Transformer Network (TN) demonstrates advantages and potential in SER. However, the limited size of available datasets and the difficulty of decoupling emotional features restrain its performance and present challenges in implementing SER on edge devices. To address these issues, we present a Memristor-based Progressive Hierarchical Conformer Architecture (MPCA) and design a conformer submodule that leverages convolution to mitigate TN’s limitations in SER. We propose attention-based feature decoupling, employing hierarchical extraction to decouple speaker characteristics and retain the relevant components, thereby obtaining reliable emotional features. Furthermore, we propose a reconfigurable circuit implementation scheme for MPCA based on operator multiplexing achieving flexible modules that can be dynamically adjusted based on the resources of edge devices, and the stability of the designed circuit is analyzed by simulation experiments with PSPICE. We show that the suggested MPCA demonstrates state-of-the-art performance in SER while significantly reducing system power consumption, offering a solution for SER implementation on edge devices.

Biochar is a type of porous carbon by obtained processing organic waste. In recent years, many scholars have dedicated themselves to the study of biochar. The research and development of a biochar manufacturing device has become the focus of numerous studies. This paper mainly describes the structure and principles of a device to obtain biochar in the laboratory. The experimental results indicate that this device can fully meet the needs of biochar manufacturing and has a bright prospect for wide promotion.

Along with the applications of distributed resources (DR), nonlinear power electronic devices and nonlinear and unbalanced loads, some deteriorative influences have been caused such as poor power quality and stability issues. The Static Synchronous compensator (STATCOM), as one of newest reactive power compensations with the best performances, plays an important role in the power system up to now. This paper deals with the fundamental compensation principle, the main circuit, current detection method, control strategy and application prospect of STATCOM which can reduce the line loss of power grid and the power loss of asynchronous motor.

With relating to basic courses of electronic professional, the theoretical teaching and the experimental teaching need synchronization, flexibility and relativity, in order to enable students to accept new knowledge faster, more deeply in the teaching process. This paper emphasizes the idea of “integrating theory with practice”. It is suggested that both experimental and theoretical courses should be paid more attention and the new knowledge will be more conducive to the transformation of knowledge.

The author suggests that the same teacher teaches theory and experimental class of the same class; pay attention to the change of students’ thinking, modify timely curriculum arrangement; rational use of multimedia teaching forms and more development of different forms of teaching resources.