A comparative study of meta-heuristic and conventional optimization techniques of grid connected photovoltaic system

This paper presents the meta-heuristic and conventional optimizations techniques for the grid connected photovoltaic solar system. The perturb and observe (P&O) and particle swarm optimization (PSO) algorithms are proposed to track the maximum power point (MPP) of the photovoltaic solar system (PVSS). The regularization of the current supplied into the grid is ensured by the proportional integral (PI) corrector whose parameters are generated by the genetic algorithm (GA). The results of these two MPPT methods are compared and showed that the PSO is more efficient than the P&O. The use of GA algorithm to determine PI parameters allowed to obtain 0.89% of total distortion harmonic (THD).

Nonlinearity Attack Against the Kichhoff–Law–Johnson-Noise (KLJN) Secure Key Exchange Protocol

This paper introduces a new attack against the Kirchhoff–Law–Johnson-Noise (KLJN) secure key exchange scheme. The attack is based on the nonlinearity of the noise generators. We explore the effect of total distortion ([Formula: see text]) at the second order ([Formula: see text]), third order ([Formula: see text]) and a combination of the second and third orders ([Formula: see text]) on the security of the KLJN scheme. It is demonstrated that as little as 1% results in a notable power flow along the information channel, which leads to a significant information leak. We also show that decreasing the effective temperature (that is, the wire voltage) and, in this way reducing nonlinearity, results in the KLJN scheme approaching perfect security.

Distortion measurements of sound pressure level generated by a pistonphone

A supplementary interlaboratory comparison on pistonphone calibration was performed between 2018 and 2020 under the auspices of the Inter-American Metrology System. Seven national metrology institutes took part in this comparison. One pistonphone was circulated among the participants for measurement of the generated sound pressure level, frequency, total distortion + noise and total harmonic distortion. This paper presents the results of distortion measurements and analyzes them. From the stability check, notable variances with respect to reported measurement uncertainty were observed. From reported results, a large difference between the estimated uncertainties by the participants was noted. Convergence between results was found when measurements were performed using one-inch microphone while some divergence between results was found when measurements were performed using half-inch microphone. In addition, these results (using one-inch and half-inch microphones), even when obtained by the same institute, sometimes were different. Reasons for these findings are discussed and suggestions for future comparisons are presented.

IMPROVED PERFORMANCE OF PHOTOVOLTAIC BASED EMBEDDED DUAL POWER SOURCE SL-QUASI Z SOURCE INVERTER FOR IM DRIVE

This paper presents the performance of PV-based embedded dual power source of SL quasi Z source inverter. The SL quasi Z source inverter with an embedded PV source and a dual power source (DPS) is injected into the system. The DPS helps the system to operate at an equilibrium state and stabilizes the entire system during PV power fluctuations. The design of the proposed system is carried out in MATLAB/Simulink environment. The control strategy with the PI controller is adopted. ESLQ Z source inverter with voltage boost method is employed with basic SPWM methodology will be suitable for IM drive applications. The system has the merit of a low inrush current that will protect and increase the life of switching devices. Finally, the study and simulation setup is validated by proving their good operating features. The proposed work is trustworthy that minimizes the total distortion factor, start-up inrush current with improved performance. Keywords: Photo voltaic (PV), embedded dual power SL quasi Z source inverter, Induction motor drive (IM), PI controller.

A Price Theory of Multi-Sided Platforms: Comment

Weyl (2010) shows that in multi-sided platform settings, profit maximization leads to classical and Spence distortions, with the Spence distortion providing a new explanation for why prices may sometimes be too high (or too low) on platforms. However, the key formulas that Weyl gives comparing privately and socially optimal prices are misstated. Properly interpreted, his results only explain marginal incentives with respect to setting prices but not the total distortion in prices, which can be very different. (JEL D42, D85, L12, L14)

Transmission Optimization of Wireless Visual Sensor Networks with Compressed Sensing Encoder

The design and optimization of wireless visual sensor network (WVSN) is challenging due to error-prone wireless link, limited resource and low computational capacity. Traditional video coding methods and layered transmission protocols are not efficient for visual information collection in WVSNs. In this paper, we adopted the compressed sensing (CS) paradigm to sense and encode the visual information, and proposed a cross-layer transmission algorithm to achieve optimal trade-off between total distortion and power consumption by simultaneously controlling the CS measurement rate and allocating the power and bandwidth for each wireless link. The algorithm was obtained by using convex dual theory and sub-gradient iterative method. The optimality condition of the proposed algorithm was also given. The algorithm can be implemented in a practical WVSN in a distributed way with only limited local information exchanges.