نشریه عصر برق
پیاپی 17 (تابستان 1401)

The growing demand for broadband services for moving devices led to the development of ESIM (Earth Station In Motion) technology. These services can be used in cars, trains, air and sea ships. The International Telecommunication Union (ITU) and many regional and national telecommunications regulators are developing standards and regulations that, when complied with by ESIM, minimize such interference. At WRC2015, the frequency band of 20.2-19.7 GHz and 29.5-30 GHz assigned to ESIM. In addition, at WRC2019, the frequency band was extended to 17.7-19.7 GHz and 27.5-29.5 GHz and the regulatory and interference considerations were raised by various countries. In WRC2023, these issues will be addressed, as well as the use of ESIM in FSS Non-GEO satellite systems in the 17.7-19.7 GHz and 27.5-29.5 GHz. Several services were already using part or all of the frequency band allocated to ESIM (GEO or Non-GEO). Service providers, operators, and regulators have largely taken into account interference and licensing processes over the years. In this research, an brief introduction of ESIM has been given. After a brief presentation on how the studies and analyzes have been done in order to extract the requirements for controlling ESIM interference in ITU documents and meetings, the initial scenarios for analysis the interference are stated. In the following, the technology of Network Control and Monitoring Center (NCMC) along with monitoring stations, monitors of radio-space spectrum, Geoloction system and the challenges of their implementation are briefly described. Finally, due to the need to provide ESIM service in the near future as well as the development of related technologies, the challenges in this area were summarized.

Mega Satellite Constellations are the latest achievement of the new space age. This technology, with a large number of satellites, at a low orbital altitude, provides the possibility of providing services with high bandwidth, low delay and competitive with other terrestrial communication platforms. One of the important requirements in establishing reliable and stable communication in satellite communication is the study of the propagation of radio waves in different frequency bands in order to extract parameters effective in the efficiency of the satellite link and creating a suitable model for predicting the effects of factors affecting wave propagation based on the parameters obtained for different regions. In this paper, in addition to a brief review of the key features of satellite constellations, as well as a more detailed review of an example of this type of new space technology, the issue of atmospheric phenomena affecting the propagation of satellite waves at Ku and Ka frequencies has been investigated. In this study, not only LEO orbit, but also the earth’s GEO various atmospheric phenomena and their effects on the satellite signal quality are described Also, in accordance with the introduced methods, a proposed arrangement sample for simultaneous measurement of satellite signal and meteorological parameters has been presented and operational measurement results have also been presented.

Recently, the ever-increasing occurrence rate of high-impact rare (HR) natural events has attracted the attention of researchers to the effects of such incidents on power systems. Examination of available data shows that HR events have the potential to shut down a significant part of the power system and disrupt the routine life of customers. To analyze the power system behavior in the face of HR events, researchers introduced the concept of power system resiliency. Reviewing HR event types threatening Microgrids, the effects of these incidents are investigated. Then, the basic concepts and elements of resilience are discussed. Presenting a state-of-the-art review of the literature, resilience-assessment metrics are discussed and compared. Finally, resilience-improving measures for Microgrids are described. Conclusive remarks are given as well.

Due to its important advantages over other forms of energy, the electrical energy is nowadays expected to keep on being the most frequently used form of consumed energy. Proper management and development of the generation, transmission and distribution systems carries significant value with respect to efficiency improvement, loss reduction, power quality and enhancement of the country infrastructure. Standardization is a focus of interest in many scientific and engineering fields. The severe competition among industries and globalization of the economy encouraged many producers around the world to approach quality production conforming to the standards. Without production line standardization, any producer will fail to achieve valuable success. It may even fail in maintaining its present statute causing income declines on a daily basis, losing competition capabilities and eventually becoming bankrupt if it does not initiate research on standardization in the current situation of the borderless world of business. Standardization in the field of electrical systems for generation, transmission and distribution in the fields of design, manufacturing, test, provision, construction, installation and commissioning of electrical equipment improves performance and is a key to proper privatization with the purpose of maintaining and continually improving the power grid as an important national infrastructure. Therefore, to review the relevant international standards, and to compare them with national standards and regula

The electrocardiogram (ECG) signal shows the electrical activity of the heart, which includes three P, QRS and T waves. The detection of R peaks and, as a result, QRS complexes, is very important in the ECG signal and provides information about the heart rate and possible abnormalities, thus helping to diagnose heart diseases. In this article, different R peak extraction methods have been investigated. These methods include PT algorithm, GR algorithm, UNSW algorithm, Tiger Energy Operator (TEO) algorithm, signal structural analysis algorithm, Hilbert transform, wavelet transform, adaptive filters, evolutionary algorithms and neural networks. Also, the performance of these methods has been evaluated based on the criteria of sensitivity, positive prediction, accuracy and detection error rate, which among the mentioned methods, TEO algorithm, Hilbert transform and convolutional neural network (CNN) have a lower detection error rate.

Quantum computing is a new method of information processing based on the concepts of quantum mechanics which leads to strange and powerful events in the field of quantum. Each unitary matrix represents a quantum gate. Synthesis of quantum circuits refers to the process of converting a quantum gate into a series of basic gates implementable in quantum technologies and is divided into two general categories, namely decomposition and composition-based. In the first category, quantum circuits are synthesized by using matrix decomposition methods and in the second category, they are synthesized by using matrix multiplication of gates. This study deals with the first category, which uses mathematical algorithms to achieve the final characteristic of a quantum circuit.