Generalized Methodology Application for System Design

The design process for analogue circuit design is formulated on the basis of the optimum control theory. The artificially introduced special control vector is defined for the redistribution of computational costs between network analysis and parametric optimization. This redistribution minimizes computer time. The problem of the minimal-time network design can be formulated in this case as a classical problem of the optimal control for some functional minimization. There is a principal difference between the new approach and before elaborated methodology. This difference is based on a higher level of the problem generalization. In this case the structural basis of design strategies is more complete and this circumstance gives possibility to obtain a great value of computer time gain. Numerical results demonstrate the effectiveness and prospects of a more generalized approach to circuit optimization. This approach generalizes the design process and generates an infinite number of the different design strategies that will serve as the structural basis for the minimal time algorithm construction. This paper is advocated to electronic systems built with transistors. The main equations for the system design process were elaborated.

Tri-valued Memristor-based Hyper-chaotic System with Hidden and Coexistent Attractors

Recently, the nonlinear dynamics of memristor has attracted much attention. In this paper, a novel fourdimensional hyper-chaotic system (4D-HCS) is proposed by introducing a tri-valued memristor to the famous L¨u system. Theoretical analysis shows that the 4D-HCS has complex chaotic dynamics such as hidden attritors and coexistent attractors, and it has larger maximum Lyapunov exponent and chaotic parameter space than the original L¨u system. We also experimentally analyze the dynamics behaviors of the 4D-HCS in aspects of the phase diagram, Poincar´e mapping, bifurcation diagram, Lyapunov exponential spectrum, and the correlation coefficient, and the analysis results show the complex dynamic characteristics of the proposed 4D-HCS. In addition, the comparison with binary-valued memristorbased chaotic system shows that the 4D-HCS has unique characteristics such as hyper-chaos and coexistent attractors. To show the easy implementation of the 4D-HCS, we implement the 4D-HCS in an analogue circuit-based hardware platform, and the implementation results are consistent with the theoretical analysis. Finally, using the 4D-HCS, we design a pseudorandom number generator to explore its potential application in cryptography.

Development of a piezoelectric pump with ball valve structure

This study designs, fabricates and tests a piezoelectric pump with the structure of a polystyrene ball check valve. The structure of the check valve consists of three layers of specially designed polymethylmethacrylate plates and six polystyrene balls, which forms a particular three-layer constraint mechanism to limit the lateral and vertical displacement of the balls. The assembly of the ball valve can be completed with a simple placing operation, which simplifies the assembly process of the entire pump. The balls are lightweight, which is beneficial for working at high frequencies. The current design adopts two compressible spaces, and the equivalent analogue circuit of compressible spaces is established and analysed. Experimental results indicate that compressible spaces can alleviate the burden in the actuator and smoothen the flow rate pulsation in the long flow channel. The theoretical analysis and experimental tests reveal that this new piezoelectric pump is self-priming. A high flow rate of 99.6 mL/min and the maximum back pressure of 15.3 kPa are obtained when the pump is driven with a sinusoidal voltage of 448 Vpp at the resonant frequency of 790 Hz.

A spiking and adapting tactile sensor for neuromorphic applications

The ongoing research on and development of increasingly intelligent artificial systems propels the need for bio inspired pressure sensitive spiking circuits. Here we present an adapting and spiking tactile sensor, based on a neuronal model and a piezoelectric field-effect transistor (PiezoFET). The piezoelectric sensor device consists of a metal-oxide semiconductor field-effect transistor comprising a piezoelectric aluminium-scandium-nitride (AlxSc1−xN) layer inside of the gate stack. The so augmented device is sensitive to mechanical stress. In combination with an analogue circuit, this sensor unit is capable of encoding the mechanical quantity into a series of spikes with an ongoing adaptation of the output frequency. This allows for a broad application in the context of robotic and neuromorphic systems, since it enables said systems to receive information from the surrounding environment and provide encoded spike trains for neuromorphic hardware. We present numerical and experimental results on this spiking and adapting tactile sensor.

The Electrical Analogue Computer of Microtubule’s Protofilament

Microtubules as essential biopolymers implicated into electrical intracellular transport open a lot of questions about their intrinsic character of dynamic instability. Both experimental and theoretical investigations are used to understand their behavior in order to mimic and build powerful and smart biomaterials. So, in this paper, by analytical and computational approaches, we proposed an electrical analogue computer of microtubule’s protofilament drawing from the partial differential equation which describes microtubule’s motion. Using the computing elements, namely, operational amplifiers, capacitors, and resistors, we designed analytically the bioelectronic circuit of the microtubule’s protofilament. To validate our model, Runge–Kutta code was used to solve the partial differential equation of MT’s motion on software Matlab, and then, the results obtained are used as a controller to fit and validate numerical results obtained by running the bioelectronic circuit on software PSpice. It is shown that the analogue circuit displayed spontaneous electrical activity consistent with self-sustained electrical oscillations. We found out that two behaviors were exhibited by the voltage generated from the electrical analogue computer of MT’s protofilament; amplification and damping behaviors are modulated by the values of the resistor of the summing operational amplifier. From our study, it is shown that low values of the resistor promote damping behavior while high values of the resistor promote an amplification behavior. So microtubule’s protofilament exhibits different spontaneous regimes leading to different oscillatory modes. This study put forward the possibility to build microtubule’s protofilament as a biotransistor.

On the zero-level offset in the GOSAT TANSO-FTS O₂ A band and the quality of solar-induced chlorophyll fluorescence (SIF): comparison of SIF between GOSAT and OCO-2

Satellite remote sensing of solar-induced chlorophyll fluorescence (SIF) has attracted attention as a method for improving the estimation accuracy of the photosynthetic production of terrestrial vegetation in recent years. The Greenhouse gases Observing Satellite (GOSAT) has the ability to observe both SIF and the concentrations of CO2 and CH4 and thus is expected to contribute to the understanding of the global carbon budget. Evaluating artefact signals (e.g. zero-level offset caused by non-linearity in the analogue circuit in the case of GOSAT) is effective for inferring the instrument status and important for retrieving SIF from satellite measurements. Here we investigate the characteristics of the zero-level offset and the consistency of satellite-derived SIFs by comparing the derived SIF with the Orbiting Carbon Observatory-2 (OCO-2) SIF at multiple spatial scales (footprint to global). The zero-level offset was evaluated using filling-in signals over bare soil while investigating the criteria for identifying barren areas. An analysis of the temporal variation of the zero-level offset over a period of 9 years suggests that the radiometric sensitivity of the GOSAT spectrometer changed after switching the optics path selector in January 2015. The GOSAT SIF was highly consistent with the OCO-2 SIF, with a bias within 0.1 mW m−2 nm−1 sr−1 for most months and an inter-region bias of about 0.2 mW m−2 nm−1 sr−1. Our results agree with the previous comparisons and support the consistency among the present satellite SIF data, which is important for the utilization of those data.

DEVELOPMENT OF INDUCTIVE SENSOR BASED ON RANDOM OSCILLATOR

The purpose of the work consists in the investigation of the possibility to use a random oscillator with the inductive coil as an inductive sensor. The work problems: methods development for the synthesis of a random oscillator with the inductive coil; development and investigation of methods for the analysis of oscillations in a random circuit at target bringing to a sensitive coil; an experimental confirmation of the results obtained theoretically. The investigation methods used in the work: a simulation, a computer experiment, a nature experiment. The investigation results: a confirmation of the hypothesis, lying in the basis of the investigation, on the applicability of random oscillators in sensor applications; a procedure for the synthesis of random oscillators with the inductive coil based on a specified random system of differential equations; data on the applicability of different kinds of the analysis of oscillations for the emphasis of information on the parameter measured, methods for these data processing. The novelty of this paper consists in that this is the first Russian language work on random sensors – a new promising direction of investigations in the field on non-linear dynamics. In this work for the first time there is used a random oscillator for the prototype formation of an approximation industrial sensor with a cup core. Conclusions: 1. On the basis of a random oscillator specified with a differential equation there may by synthesized a sensitive electric analogue circuit. 2. Using a simple geometrical analysis of an attractor it is possible to define a value of the parameter (inductivity) under measurement with high accuracy and to transform this value into data on a distance to an aim.

On the zero-level offset in the GOSAT TANSO-FTS O₂ A-band and the quality of solar-induced chlorophyll fluorescence (SIF): Comparison of SIF between GOSAT and OCO-2

Satellite remote sensing of solar-induced chlorophyll fluorescence (SIF) has attracted attention as a method for improving the estimation accuracy of the photosynthetic production of terrestrial vegetation in recent years. The Greenhouse gases Observing SATellite (GOSAT) has the ability to observe both SIF and the concentrations of CO2 and CH4 and thus is expected to contribute to understanding of the global carbon budget. Evaluating artifact signals (e.g., zero-level offset caused by non-linearity in the analogue circuit in the case of GOSAT) is effective for inferring the instrument status and important for retrieving SIF from satellite measurements. Here we investigate the criteria for identifying vegetation-free areas to evaluate the zero-level offset and the offset correction method, while comparing the derived SIF with the Orbiting Carbon Observatory-2 (OCO-2) SIF at multiple spatial scales (footprint to global). The criteria were determined as a small variation in the radiance within the GOSAT instantaneous field of view for cloudy ocean scenes and a higher albedo in the 2.0 μm band than in the 1.6 μm band for bare soil scenes, which were slightly different from the previously used criteria. The GOSAT SIF that was most consistent with the OCO-2 SIF was obtained when the zero-level offset was evaluated from bare soil over the globe, with a bias of about 0.1 mW m−2 nm−1 sr−1. Our results agree with the previous comparisons and support the consistency among the present satellite SIF data, which is important for the utilization of those data. An analysis of the temporal variation of the zero-level offset over a period of 9 years suggests that the radiometric sensitivity of the GOSAT spectrometer changed after switching the optics path selector in January 2015.