Tom 73 (2022): Zeszyt 5 (September 2022)

This paper proposes a new inverter control strategy whose main purpose is to reduce the current harmonic distortion resulting from unnecessary control actions without sacrificing the system’s dynamic response. The brain’s capabilities to learn and react to stress are mimicked to generate control actions based on emotional cues. The model is based on the brain emotional learning based intelligent controller, to which an autonomous nervous system was added. The modified controller aims at separating the strategy during transient states from the one during steady states. The proposed method was compared to the PI controller, the PR controller, and a neural network-based controller on Matlab Simulink. It shows major improvements in terms of harmonic distortion and a complete removal of the inter-harmonics. It provides a good dynamic response in transient states and an immunity to irrelevant signal variations during the steady state, which results in an improvement in the harmonic production.

In our paper, we have proposed to use graphs to detect anomaly in human action video. Although the detection of anomaly is a widely researched topic, but very few researchers have detected anomaly in action video using graphs. in our proposed method we have represented the smaller section (sub-section) of our input video as a graph where vertices of the graph are the space time interest points in the sub-section video and the association between the space time interest points exists. Thus, graphs for each sub section are created to look for a repeated substructure. We believe most of the actions inherently are repeated in nature. Thus, we have tried to capture the repetitive sub-structure of the action represented as a graph and used this repetitive sub-structure to compress the graph. If the compressed graph has few elements that have not been compressed, we suspect them as anomaly. But the threshold value takes care not to make the proposed method very much sensitive towards the few uncompressed elements. Our proposed method has been implemented on locally created “extended KTH” and “extended Weizmann” datasets with good accuracy score. The proposed method can also be extended for few more applications such as training athletes and taking elderly care.

In this study, a modified version of salp swarm algorithm (MSSA) is used to synthesize elliptical antenna arrays (EAAs). The original salp swarm algorithm (SSA) is an optimization algorithm inspired by the behavior of salps in nature, which is used to solve engineering problems. The main purpose of the synthesis in this study is to obtain an EAA pattern with low maximum sidelobe levels (MSLs) for a fixed narrow first null beamwidth (FNBW). For different examples, the amplitude and angular position values of the antenna array elements are considered as optimization parameters. To show the effectiveness of the MSSA, eight examples of EAAs with 8, 12, and 20 elements are given. The results obtained with MSSA are compared with those of the antlion optimization, symbiotic organizations search, flower pollination algorithm, and accelerated particle swarm optimization from the literature. It is clear from the numerical results that MSSA outperforms the other algorithms in terms of the suppression of MSL.

This manuscript presents a design of a differentiator in the digital domain with its low noise realization. It manifests the minimization of the L₁ -error objective function by using a hybrid optimization technique consisting of the particle swarm and simulated annealing optimization algorithm. The obtained magnitude response provides a noteworthy approximation of the ideal differentiator with a minimal magnitude inaccuracy when compared with the existing designs. The realization structures are also investigated and compared in terms of the noise gain behavior.

A triple path dual resistive feedback noise cancellation (TP-DRNC) low noise amplifier (LNA) with transformer output presented which provides high gain, low noise figure (NF), and high figure of merit (F_M). The analysis of triple path, dual resistive, gain, and NF have been discussed. The effect of various components used in the circuit have been analyzed and their optimized values are obtained which resulted in the high (F_M). The combination of dual resistive feedback with triple path NC transformer output allowed for low NF and high gain. The proposed GPDK 45 nm complementary metal oxide semiconductor (CMOS) technology-based LNA offers a flat gain curve of 10.81 dB over the range of 1.6 GHz to 4.3 GHz, or 2.7 GHz bandwidth, and S₁₁ less than −9 dB. The input third order intercept point (IIP3) for the given bandwidth has value of 5.7 dBm, while the minimal NF achieved is 2.7 dB; (F_M1) is 14.026 and (F_M2) is 12.48. The proposed LNA’s layout with an o -chip transformer has an area of 0.01985 mm²

The article is devoted to the complete design of an intelligent barrier that uses piezoelectric ceramic transducers as transmitter of an acoustic signal and as a receiver. There is a relatively rich device base on the market for these transducers. These transducers are also not economically demanding. The barrier is composed of three identical bars. A continues wave rectangular signal generation is used for excitation of the converters on the transmitting side. The receiving side is more complex. A signal from the receiving transducer is first analog pre-processed and converted to logical values of 0 or 1. Subsequently, these signals are processed in a microcontroller system, evaluated and a possible alarm of a presence of an intruder is signaled using a display, a light-emitting diode and a piezoelectric siren. The display also shows the number of alarms. Some intelligence is added to the system by classifying a potential intruder. The functionality of the system is verified in a detail and discussed.

Diamond is recognized as one of the most promising wide bandgap materials for advanced electronic applications. However, for many practical uses, hybrid diamond growth combining metal electrodes is often demanded. Here, we present the influence of thin metal (Ni, Ir, Au) layers on diamond growth by microwave plasma chemical vapor deposition (MWCVD) employing two different concepts. In the first concept, a flat substrate (GaN) was initially coated with a thin metal layer, then exposed to the diamond MWCVD process. In the second concept, the thin diamond film was firstly formed, then it was overcoated with the metal layer and finally, once again exposed to the diamond MWCVD. It should be mentioned that this concept allows the implementation of the metal electrode into the diamond bulk. It was confirmed that the Ni thin films (15 nm) hinder the formation of diamond crystals resulting in the formation of an amorphous carbon layer. Contrary to this finding, the Ir layer resulted in a successful overgrowth by the fully closed diamond film. However, by employing concept 2 (ie hybrid diamond/metal/diamond composite), the thin Ir layer was found to be unstable and transferred into the isolated clusters, which were overgrown by the diamond film. Using the Au/Ir (30/15 nm) bilayer system stabilized the metallization and no diamond growth was observed on the metal layer.

Due to the lack of efficient specified multi-hop routing protocol, IEEE 802.11 ad hoc networks have been in limited use for realizing wireless sensor networks where wireless sensors are dispersed in a region and each sensor can transmit its data to one another. We propose a novel MAC routing protocol for IEEE 802.11 wireless sensor networks, of which the service areas are extended by appropriately appointed pseudo-access points.

Voicing is an important phonetic characteristic of speech. Each phoneme belongs to a group of either voiced or unvoiced sounds. We investigated and compared the performance of five algorithms widely used to estimate speech voicing. All algorithms were implemented in Matlab and tested on both short consonants and continuous speech. Phonetically paired consonants (voiced vs unvoiced) and parts of read speech from audio books were used in the experiments. The tuned harmonics-to-noise ratio method gave the best results in both situations, ie for consonants and continuous speech. Using this method, the overall voicing of Czech, Polish, Hungarian and English was investigated. Hungarian speech showed the highest proportion of voiced parts, approx. 75 %. In other languages, the proportion of voiced parts was around 70 %.

This paper deals with single and three phase multilevel inverters power quality. The voltage total harmonic distortion rate is an important criterion for choosing the number of inverter levels and checking compatibility with power quality requirements. In this study, the author raises an interesting issue related to the definition of voltage THD boundaries with upper and lower limits. The problem is reformulated, and a novel and more practical approach is developed for three- and single-phase multilevel inverters. Found upper and lower voltage THD limits are sufficiently verified with most known switching algorithms like sinusoidal modulation (SM) with phase disposition (PD), space vector modulation (SVM) and selective harmonic elimination (SHE). They are also valid for cascaded (H-Bridge), neutral point clamped (NPC) and flying capacitors (FC) multilevel inverters.