On the dynamics of a new memristive diode emulator-based Chua’s circuit

Achieving comprehensive code quality and ensuring software reliability are critical goals in modern software engineering. This paper delves into advanced strategies that encompass both technical and organizational practices, aiming to enhance code quality and boost software reliability. Key strategies include the implementation of rigorous code review processes, adoption of automated testing frameworks, and the utilization of static and dynamic code analysis tools. Firstly, rigorous code review processes are fundamental for maintaining high standards of code quality. By fostering a collaborative environment where peer reviews are routine, teams can catch potential issues early, ensure adherence to coding standards, and promote knowledge sharing. This practice not only improves code quality but also enhances team cohesion and expertise. Secondly, automated testing frameworks are indispensable in achieving comprehensive test coverage and reducing the incidence of bugs. Unit tests, integration tests, and end-to-end tests, when automated, provide continuous feedback and ensure that code changes do not introduce new defects. This continuous testing approach is crucial for maintaining software reliability, especially in agile and DevOps environments where rapid iterations are common. Furthermore, the integration of static and dynamic code analysis tools into the development pipeline offers additional layers of quality assurance. Static analysis tools inspect the codebase for potential vulnerabilities, code smells, and compliance with coding standards without executing the program. Dynamic analysis tools, on the other hand, evaluate the software during runtime to detect memory leaks, concurrency issues, and performance bottlenecks. Together, these tools provide a comprehensive assessment of the code’s health and reliability. Moreover, fostering a culture of continuous improvement and learning within the development team is essential. Regular training sessions, workshops, and knowledge-sharing activities help in keeping the team updated with the latest advancements in software engineering practices and tools. Encouraging a mindset of quality-first and reliability among developers ensures long-term benefits and sustainability. In conclusion, achieving comprehensive code quality and ensuring software reliability require a multifaceted approach that integrates rigorous code reviews, automated testing frameworks, and both static and dynamic analysis tools. Coupled with a strong culture of continuous learning and improvement, these strategies collectively contribute to the development of robust, reliable, and high-quality software systems. Keywords: Software Reliability, Code Quality, Advanced, Strategies, Comprehensive.

The aim of this study was to investigate, in a tube model, how the speed of a mucous simulant was influenced by angle and different types of oscillations. Using a repeated-measures study design, the primary outcome measure was the mucous simulant speed calculated from the time taken for the mucous simulant to travel a distance of 10 cm. Ultrasonic gel diluted to a viscosity (113 Poise), approximating human sputum, was introduced into a flexible tube similar in diameter to the human adult trachea. The tube was subjected to discrete angles of 0 degrees and 30 degrees, 60 degrees and 90 degrees downward. Symmetrical oscillation was applied in both the transverse and longitudinal directions with frequencies of 5, 15 and 25 Hz at amplitudes of 1 mm and 2 mm peak-to-peak using a commercially available oscillator. Asymmetrical oscillation was applied using repeated cycles of slow acceleration and fast deceleration in the longitudinal direction at 0 degrees and 30 degrees downward and up a 5 degrees incline using a custom-built apparatus. Each 30 degrees angle increment of the tube from 0 degrees to 90 degrees significantly increased mucous simulant speed (p<0.001). Symmetrical oscillation did not provide an advantage over angle in terms of mucous simulant speed; however, asymmetrical oscillation increased mucous simulant speed beyond that caused by angle for all angles tested (p<0.001) and was able to drive mucous simulant up a small incline (5 degrees) in this tube model. It was found that certain types of longitudinal oscillation elongated the mucous simulant. The present study supports the use of gravity to assist in secretion clearance. Asymmetrical oscillation is a novel technique which warrants further investigation.

This study presents two improved designs of eccentric-shaped permanent magnets and teeth-shaped stators in radial-flux dual three-phase permanent magnet electric machines to reduce cogging torque and torque ripple. The finite element analysis (ANSYS Electromagnetics) has been adopted in simulation, and real radial-flux dual three-phase permanent magnet electric machines have been fabricated in experiment to verify the study. Using the radial-flux dual three-phase permanent magnet electric machines in electric machine systems can improve the reliability and obtain higher output torque. In electrical drives and control, a simplified model-free predictive current control method has been proposed and implemented to drive the radial-flux dual three-phase permanent magnet electric machines, and the control law has been achieved by a TMS320F28377S microcontroller of Texas Instruments. The simplified model-free predictive current control method is senseless to parameter variations and back electromotive force of the permanent magnet electric machines, and only needs current sensors to detect six-phase current. The optimal one has been chosen by 14 various switching modes, which has the minimum cost function, and then the converter can be directly driven and controlled in the next sampling period. The features of the simplified model-free predictive current control method can reduce the algorithm calculation and avoid the defect of conventional model-based predictive current control scheme. A proportional-integral speed controller has also been designed to achieve the speed response of the fixed-speed tracking effect. Finally, the feasibility and effectiveness of the proposed simplified model-free predictive current control method for the dual three-phase permanent magnet electric machines can be verified in the experimental and quantitative results.

Chaos is ubiquitous in nonlinear dynamical systems. It is a hidden state of deterministic disorder in certain regions of parameters and initial conditions of a nonlinear system. The path taken by the system to reach chaos is known as its route to chaos. The state of the system can drastically change from a stable fixed point or a periodic solution to chaos due to the effect of local or global bifurcation. The available tools, such as bifurcation diagrams, Lyapunov spectra, Poincaré maps, phase plots, and time series plots, explore the routes for such qualitative changes. These are tiresome procedures. For more efficient verifications, this work offers a guide or catalog for several routes to chaos (RTC) through which a continuous-time dynamical system enters or exits from chaos. Additionally, this review paper highlights various signatures associated with common RTC to make identification easier. The main emphasis is on enabling a reader to assess these RTC by merely observing the explained signatures in the bifurcation diagrams and the Poincaré maps.

The paper reports the simplest 4-D dissipative autonomous chaotic system with line of equilibria and many unique properties. The dynamics of the new system contains a total of eight terms with one nonlinear term. It has one bifurcation parameter. Therefore, the proposed chaotic system is the simplest compared with the other similar 4-D systems. The Jacobian matrix of the new system has rank less than four. However, the proposed system exhibits four distinct Lyapunov exponents with $$(+, 0, -, -)$$ sign for some values of parameter and thus confirms the presence of chaos. Further, the system shows chaotic 2-torus $$(+,0,0,-)$$ , quasi-periodic $$[(0,0,-,-), (0,0,0,-)]$$ and multistability behaviour. Bifurcation diagram, Lyapunov spectrum, phase portrait, instantaneous phase plot, Poincare map, frequency spectrum, recurrence analysis, 0–1 test, sensitivity to initial conditions and circuit simulation are used to analyse and describe the complex and rich dynamic behaviour of the proposed system. The hardware circuit realisation of the new system validates the MATLAB simulation results. The new system is developed from the well-known Rossler type-IV 3-D chaotic system.

Memristor is a kind of resistance with a memory function and its special properties decide its broad prospect for application. At present, the focus and difficulty of the research in memristor lie in the establishment of new models and related applications. Therefore, in this paper a new continuous and smooth memristor model is put forward first and the correctness of this new model is proved through the study in the phase trajectory relationship between voltage and current. Then based on Chua’s circuit, a new fifth-order hyper-chaotic circuit including two new memristor models is designed and the dimensionless mathematical model is deduced. By the classical nonlinear method of circuit analysis, the dissipation of the new system is put into study in this paper. It is proved through numerical simulation, bifurcation diagram, Lyapunov spectrum that the new system has its unique dynamical behavior. At last, chaotic sequence of the new system is used to encrypt the image and the encrypted histogram, the correlation and anti-attack capability between adjacent pixels and the key sensitivity are emphatically analyzed. It turns out that when applied to image encryption, the newly proposed memristor chaotic system has relatively high safety performance.

Global aspects of turbulence induced by heteroclinic cycles in competitive diffusion Lotka–Volterra equation

Detailed investigation of the bifurcation diagram of capacitively coupled Josephson junctions in high-Tc superconductors and its self similarity

Stepper motors are employed in a wide range of consumer and industrial applications. Their use is simple: a digital device generates pulse-bursts and a direction bit towards a power driver that produces the 2-phase currents feeding the motor windings. Despite its simplicity, this open-loop approach fails if the torque load exceeds the motor capacity, so the motor and driver should be oversized at the expense of efficiency and cost. Field-Oriented closed-loop Control (FOC) solves the problem, and the recent availability of low cost electronics devices like Digital Signal Processors, Field Programmable Gate Arrays (FPGA), or even Microcontrollers with dedicated peripherals, fostered the investigation and implementation of several variants of the FOC method. In this paper, a simple and economic FOC torque control method for hybrid stepper motors is presented. The load angle is corrected accordingly to the actual shaft position through pulse-bursts and direction commands issued towards a commercial stepper driver, which manages the 2-phase winding currents. Thanks to the FPGA implementation, the control loop updates the electrical position every 50 μs only, thus allowing a load angle accuracy of −1/100 rad for a rotor velocity up to 750 rev/min, as shown in the reported experiments.

Taking the air conditioner cluster as the object, under the condition of individual perception and controllable state of the air conditioner, the cluster state is given a considerable and controllable function. In the analysis of the load model of a single air conditioner, considering the comfort of indoor temperature, the characteristics of on and off are given, that is, the cycle of on time and off time; on this basis, the air conditioning clusters are divided according to the same or similar switching cycles, thereby forming a switching strategy of series and parallel groups to achieve load balance. In the on state, if the adjustment of the power of the air conditioner itself is not considered, a simple aggregation control method is given. The analysis of numerical examples shows that this method is simple and reliable.

A simple and sensitive quality control method of the anaerobic atmosphere for identification and antimicrobial susceptibility testing of anaerobic bacteria

This paper presents a simple and effective control method to control the output voltage of DC-DC converters. The proposed method overcomes the problems associated with PWM hysteresis control. The method is also simpler and easier to implement than one cycle control (OCC). Boost, buck-boost, buck and cuk converters are selected for study. Two cases of study are included. The first represents disturbances that nay occur in the converter input voltage while the second represents the change in the converter output reference voltage. Simulation results validate the effectiveness of applying the proposed method to DC-DC converters.

The general model predictive current control uses a discrete-time model of the system to predict the future current behavior for all the possible voltage vectors generated by the inverter, and then the vector which minimizes a cost function is selected and applied. In this paper, a simplified model predictive current control method for a three-phase voltage-source inverter is presented in order to reduce the amount of calculations in the practical implementation of this method, especially for multilevel ones with large predictions. Utilizing the sector information of the reference voltage space vector, the proposed method just needs a subset of all the available voltage vectors for the prediction and optimization. The computational effort has been greatly reduced while the steady-state performance and dynamic response of the current control are improved. In addition, a reduced switching frequency is obtained. Simulation results are presented to verify the proposed method.

This paper presents a novel simplified digital control method for active power filters. By forcing the mains current to be linear with the mains voltage, the functions of harmonics elimination, reactive power compensation and unbalance correction are realized. In the proposed control method, only the mains currents and the dc bus voltage of the inverter are required to be detected. And with simple calculation, the duty ratios of switches in each switching cycle are got. So the fully digital control is easy to realize, the complex calculation in the conventional instantaneous reactive power theory is avoided and the difficulty in realizing digital control caused by the hysteresis is overcome. The viability and effectiveness of the proposed control method is demonstrated by simulation and experimental results.

In this paper a simplified and stable high frequency injection sensorless control method for reluctance synchronous machine drives is presented. This method is based on previous work where the conventional band pass filter is omitted from the demodulation scheme to prevent unnecessary time delay and magnitude decrease. Previous work presented accurate position estimation at very low speed under no-load conditions. The proposed method is evaluated under various different load conditions and at high speeds. The performance of the proposed method is compared to the performance of the drive while using a rotary encoder. Experimental results show that the scheme is stable under various load conditions and delivers good performance. (6 pages)