Symmetric quadratic tetration interpolation using forward and backward operation combination

The existed interpolation method, based on the second-order tetration polynomial, has the asymmetric property. The interpolation results, for each considering region, give individual characteristics. Although the interpolation performance has been better than the conventional methods, the symmetric property for signal interpolation is also necessary. In this paper, we propose the symmetric interpolation formulas derived from the second-order tetration polynomial. The combination of the forward and backward operations was employed to construct two types of the symmetric interpolation. Several resolutions of the fundamental signals were used to evaluate the signal reconstruction performance. The results show that the proposed interpolations can be used to reconstruct the fundamental signal and its peak signal to noise ratio (PSNR) is superior to the conventional interpolation methods, except the cubic spline interpolation for the sine wave signal. However, the visual results show that it has a small difference. Moreover, our proposed interpolations converge to the steady-state faster than the cubic spline interpolation. In addition, the option number increasing will reinforce their sensitivity.

Classifying European cigarette consumption trajectories from 1970 to 2015

ObjectivesTo systematically code and classify longitudinal cigarette consumption trajectories in European countries since 1970.DesignBlinded duplicate qualitative coding of periods of year-over-year relative increase, plateau, and decrease of national per capita cigarette consumption and categorisation of historical cigarette consumption trajectories based on longitudinal patterns emerging from the data.Setting41 countries or former countries in the European region for which data are available between 1970 and 2015.ResultsRegional trends in longitudinal consumption patterns identify stable or decreasing consumption throughout Northern, Western and Southern European countries, while Eastern and Southeastern European countries experienced much greater instability. The 11 emergent classes of historical cigarette consumption trajectories were also regionally clustered, including a distinctive inverted U or sine wave pattern repeatedly emerging from former Soviet and Southeastern European countries.ConclusionsThe open-access data produced by this study can be used to conduct comparative international evaluations of tobacco control policies by separating impacts likely attributable to gradual long-term trends from those more likely attributable to acute short-term events. The complex, regionally clustered historical trajectories of cigarette consumption in Europe suggest that the enduring normative frame of a gently sloping downward curve in cigarette consumption can offer a false sense of security among policymakers and can distract from plausible causal mechanisms among researchers. These multilevel and multisectoral causal mechanisms point to the need for a greater understanding of the political economy of regional and global determinants of cigarette consumption.

Combined Vector and Direct Controls Based on Five-Level Inverter for High Performance of IM Drive

The goal of this study was to figure out how to regulate an induction motor in a hybrid electric vehicle. Conventional combined vector and direct control induction motors take advantage of the advantages of vector control and direct torque control. It is also a method that avoids some of the difficulties in implementing both of the two control methods. However, for this method of control, the statoric current has a great wealth of harmonic components which, unfortunately, results in a strong undulation of the torque regardless of the region speed. To solve this problem, a five-level neutral point clamped inverter was used. Through multilevel inverter operation, the voltage is closer to the sine wave. The speed and torque are then successfully controlled with a lower level of ripple in the torque response which improves system performance. The analysis of this study was verified with simulation in the MATLAB/Simulink interface. The simulation results demonstrate the high performance of this control strategy.

Android Function Generator

The paper focuses on an application that can be developed on android, Android is a multipurpose operating system based on Linux for mobile devices such as smartphones and tablet computers, it contains several versions such as donot, ice-cream sandwich, KitKat, pie, etc. Function generator is a device used to generate a wide range of standardized electrical pulses such as sine wave, square wave and sawtooth wave whose frequency ranges from 0.1Hz to 11,000 Hz .In this paper we aim to review how this function generator can be developed using an android mobile application. The mobile phone application uses android in order to implement a function generator which generates different A.C sources available in the laboratory. This can be used extensively in remote areas where it is not easy to carry the function generator. Keyword: Function Generator, Android, CRO, Signals

Performance Analysis of PWM Based Full Wave Bridge Inverter

An obvious device for the utilization of renewable energy sources is inverter and Pulse Width Modulation technique is widely used method for voltage source inverters. This paper deals with the generation of PWM signals by analog circuit, where the comparison of sine wave and sawtooth wave for the operation of power circuit takes place. The above mentioned technique is studied and verified by Simulating the circuit. The prototype of PWM based, single phase, full bridge inverter is developed and the results are verified for the nominal voltage and frequency with the help of simulation and hardware is designed. Keywords: Inverter, SPWM, VSI, Simulation, MATLAB

Reduction of Coil-Crack Angle Sensitivity Effect Using a Novel Flux Feature of ACFM Technique

Alternating current field measurement (ACFM) testing is one of the promising techniques in the field of non-destructive testing with advantages of the non-contact capability and the reduction of lift-off effects. In this paper, a novel crack detection approach was proposed to reduce the effect of the angled crack (cack orientation) by using rotated ACFM techniques. The sensor probe is composed of an excitation coil and two receiving coils. Two receiving coils are orthogonally placed in the center of the excitation coil where the magnetic field is measured. It was found that the change of the x component and the peak value of the z component of the magnetic field when the sensor probe rotates around a crack followed a sine wave shape. A customized accelerated finite element method solver programmed in MATLAB was adopted to simulate the performance of the designed sensor probe which could significantly improve the computation efficiency due to the small crack perturbation. The experiments were also carried out to validate the simulations. It was found that the ratio between the z and x components of the magnetic field remained stable under various rotation angles. It showed the potential to estimate the depth of the crack from the ratio detected by combining the magnetic fields from both receiving coils (i.e., the x and z components of the magnetic field) using the rotated ACFM technique.

Reduction of Coil-Crack Angle Sensitivity Effect Using a Novel Flux Feature of ACFM Technique

Alternating current field measurement (ACFM) testing is one of promising techniques in the field of non-destructive testing with advantages of the non-contact capability and the reduction of lift-off effects. In this paper, a novel crack detection approach is proposed to reduce the effect of the angled crack (cack orientation) by using rotated ACFM techniques. The sensor probe is composed of an excitation coil and two receiving coils. Two receiving coils are orthogonally placed in the centre of the excitation coil where the magnetic field is measured. It is found that the change of the x component and the peak value of the z component of the magnetic field when the sensor probe rotates around a crack follows a sine wave shape. A customised accelerated finite element method solver programmed in MATLAB is adopted to simulate the performance of the designed sensor probe which can significantly improve the computation efficiency due to the small crack perturbation. The experiments have also been carried out to validate the simulations. It is found that the ratio between the z and x components of the magnetic field remains stable under various rotation angles. It shows the potential to estimate the depth of the crack from the ratio detected by combining the magnetic fields from both receiving coils (i.e., the x and z components of the magnetic field) using the rotated ACFM technique.

Power Conversion Techniques Using Multi-Phase Transformer: Configurations, Applications, Issues and Recommendations

Recently, the superiority of multi-phase systems in comparison to three-phase energy systems has been demonstrated with regards to power generation, transmission, distribution, and utilization in particular. Generally, two techniques, specifically semiconductor converter and special transformers (static and passive transformation) have been commonly employed for power generation by utilizing multi-phase systems from the available three-phase power system. The generation of multi-phase power at a fixed frequency by utilizing the static transformation method presents certain advantages compared to semiconductor converters such as reliability, cost-effectiveness, efficiency, and lower total harmonics distortion (THD). Multi-phase transformers are essential to evaluate the parameters of a multi-phase motor, as they require a multi-phase signal that is pure sine wave in nature. However, multi-phase transformers are not suitable for variable frequency applications. Moreover, they have shortcomings with regard to impedance mismatching, the unequal number of turns which lead to inaccurate results in per phase equivalent circuits, which results in an imbalance output in phase voltages and currents. Therefore, this paper aims to investigate multi-phase power transformation from a three-phase system and examine the different static multi-phase transformation techniques. In line with this matter, this study outlines various theories and configurations of transformers, including three-phase to five-, seven-, eleven-, and thirteen-phase transformers. Moreover, the review discusses impedance mismatching, voltage unbalance, and per phase equivalent circuit modeling and fault analysis in multi-phase systems. Moreover, various artificial intelligence-based optimization techniques such as particle swarm optimization (PSO) and the genetic algorithm (GA) are explored to address various existing issues. Finally, the review delivers effective future suggestions that would serve as valuable opportunities, guidelines, and directions for power engineers, industries, and decision-makers to further research on multi-phase transformer improvements towards sustainable operation and management.