In this paper, we focus on a novel simple chaotic circuit with a memristor, a memcapacitor and a linear inductor in parallel. Then we establish the circuit’s dimensionless mathematical model. ...Nineteen types of different chaotic attractors are found in the circuit. The chaotic system’s equilibrium point and stability are analyzed by using the traditional dynamic analysis methods, and the dynamical behaviors with three varying parameters of this circuit are analyzed in detail. Furthermore, some special phenomena such as state transition, chaos degradation and the multiple coexisting attractors are discovered. Finally, we implement this circuit through the DSP platform and the results illustrate the validity of the theoretical analysis. Theoretical analysis and simulation results indicate that the simple chaotic circuit has very rich dynamical characteristics.
•Insolation received on PV surface at various tilt angles was assessed.•Taguchi method was applied to evaluate optimal factors.•Enforced fuzzy logic MPPT, optimized by chaos PSO.•Employed ...DSP-in-the-loop based on Opal-RT OP5600.
Solar photovoltaic (PV) cells have attracted substantial interest recently owing to environmental concerns and the energy crisis. However, the efficiency of power generation by solar PV cells depends on various factors, such as climatic conditions and tilt angle. Therefore, maximum power point tracking (MPPT) for PV modules is important. This work proposes a novel robust design, which relies on various combinations of insolations, temperatures, and tilt angles, in a stand-alone PV system with MPPT. Orthogonal experiments are carried out using the Taguchi method, avoiding a full factorial experimental design. In the proposed Taguchi-based MPPT robust design of the PV system, insolation and temperature are regarded as an input and ‘noise’, respectively; insolation passage, tilt angle, and load resistance are factors that affect the results of the Taguchi experiments in multiple scenarios. A fuzzy logic controller, tuned by chaos particle swarm optimization (PSO) was utilized to implement MPPT. A stand-alone PV system was used to demonstrate the results that were obtained by the robust design of MPPT and applicability of the proposed method. Finally, a Digital Signal Processor-in-the-Loop simulation was performed using an OP5600 real-time digital simulator by Opal-RT to demonstrate the viability of the proposed scheme.
Human evolution is divided into two parts, the evolution of DNA-dominated human body and the evolution of brain-dominated human behavior. Therefore, the study of brain function provides clues to ...explore human evolution. In computational neuroscience, mathematical neuron models can be used to describe the biological functions of the brain, especially discrete neuron models. From the concept of neuroscience, discrete fractional-order (FO) neuron models combine memories into a dynamical model, which is essential for analyzing neuron model functions. In this paper, a class of FO-bi-Rulkov neuron map and introduce discrete memristor to estimate neurons exposed to electromagnetic radiation (EMR) is proposed. The effects of order variation, especially incommensurate-order, are analyzed. The basic and complex dynamical behavior of neuron are explored by multiple characteristic analysis methods. Finally, a digital circuit implementation of the neuron model is performed. This work provides a basis and application for future research on FO discrete neuron models.
•A fractional-order discrete neuron map considering the case of Electromagnetic Radiation is proposed.•Unlike many studies where incommensurate-order is considered. It can describe the memory function of the brain more precisely.•Strikingly, biological behaviors of neuronal map, such as asymptotic periodic and chaotic spike firing, are also present in FO-bi-Rulkov neuron map.•Complex dynamical behavior, including multistability, offset-boosting behavior are presented.•The digital circuit of the chaotic attractors are designed and implemented on the DSP platform, and the achievability of the FO-bi-Rulkov neuron map are verified.
In recent years, memristors have shown great potential in building artificial neural networks. Many researchers have worked on improving and innovating the design of memristors. The bifunctional ...memristor proposed in this paper provides new ideas for establishing artificial neural networks. And a novel second-order memristor Hindmarsh–Rose neuron (SOM-HR) is constructed on this basis. The SOM-HR model can well simulate the dynamical behavior of the memristive autapse HR neuron under electromagnetic radiation (EMR), and many types of firing patterns, coexisting firing patterns and state transition are found. In addition, the correctness of the numerical simulation is verified by circuit simulation and digital signal processor (DSP) implementation. Finally, the chaotic sequences generated by this model are used for image encryption, which guarantees the security of the encryption scheme. The results of the study provide a reference for construction and application of complex neural network.
•A second-order flux-controlled memristor is designed.•An analog circuit for the memristor was constructed.•Biological neuron modeling based on bifunctional memristor•The dynamical behavior of the new neural model is analyzed.•The neuron model was implemented by analog circuit and DSP platform respectively.
Orthogonal frequency-division multiplexing-based passive optical network (OFDM-PON) with low-cost direct detection is the current research focuses of access networks. It can realize multi-dimensional ...bandwidth allocation based on subcarriers and time slots. In general, the inverse fast Fourier transform (IFFT) with Hermitian symmetric (HS) mapped symbols is applied to generate the real-valued baseband signal for intensity modulation. However, only half of the subcarriers can be employed to carry user data, while the other half are modulated by the corresponding conjugate data. Therefore, both IFFT and FFT are not fully utilized in HS-OFDM systems. Under the same bandwidth granularity (data subcarriers) and data transmission rate, the non-HS OFDM (NHS-OFDM) can reduce IFFT/FFT size by half. The hardware implementation and power consumption will be significantly reduced compared to the HS-OFDM. In this paper, we design and implement the baseband HS/NHS-OFDM transceivers based on field programmable gate array chips and data converters. On-chip resource usage and power consumption are analyzed and compared. It shows that the NHS-OFDM transmitter (receiver) can save up to 58% (58%) multipliers, 46.8% (41.7%) registers, and 48% (42.9%) look-up tables. About 11.9% (19.6%) of on-chip power consumption is reduced for the transmitter (receiver). In addition, the two real-time baseband transceivers are comparatively investigated in a directly-modulated laser-based direct detection transmission system. The bit error rate (BER) performance after 20 km standard single-mode fiber transmission is measured with both offline and real-time digital signal processing (DSP) algorithms. It exhibits that the NHS-OFDM system’s power penalty is negligible at the BER of 3.8e−3, compared to the HS-OFDM. Moreover, the real-time receivers have a similar BER performance to corresponding offline ones.
•We designed and implemented low-complexity real-time NHS-OFDM transceivers based FPGA for the low-cost PON.•A modified C2R/R2C conversion method is proposed for the NHS-OFDM transceivers.•A low-complexity timing synchronization method is employed in real-time NHS-OFDM systems.
Magnetic mesoporous carbon (Fe3O4@C, MMC) was synthesized and characterized. It was used for the first time as a sorbent for the magnetic dispersive solid phase microextraction (M-dSPμE) of copper ...and lead in water and vegetables. FAAS was used to determine the analyte concentrations after elution. The MMC was found to be have surface area of 145.9 m2 g−1 and average pore diameter of 15 nm. The analytical parameters affecting M-dSPμE of copper and lead were optimized. They were pH of sample, 6; eluent, 2 mol L−1 HCl (3 mL); and sample volume, 250 mL. The MMC reaches equilibrium very fast without vortexing for adsorption and only 5 s for elution. The LOD and PF of the M-dSPμE method for copper and lead were found to be 0.87 μg L−1 and 83 for Cu(II) and 2.8 μg L−1 and 167 for Pb(II), respectively. The precision of the M-dSPμE method was found to be ≤ 3.2%. The M-dSPμE method was verified by certificate reference materials (TMDA-53.3 Fortified Lake water and NIST SRM 1573a Tomato Leaves). It was successfully applied to the determination of copper and lead in lake water, wastewaters, sea water, radish, spinach, lettuce, and celery samples.
Display omitted
•Magnetic mesoporous carbon (Fe3O4@C, MMC) was synthesized and characterized.•It was used as a sorbent for M-dSPμE of Cu(II) and Pb(II).•No vortex is required for adsorption of analyte ions on MMC.•MMC adsorbent showed high selectivity for the adsorption of analytes.•The analysis of copper and lead was made in water and vegetables.
PDF
