scholarly journals Review of Isolated Matrix Inverters: Topologies, Modulation Methods and Applications

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2394
Author(s):  
Oleksandr Korkh ◽  
Andrei Blinov ◽  
Dmitri Vinnikov ◽  
Andrii Chub

This paper presents a review of isolated matrix inverters. The study contributes to creating a point of reference for a comprehensive classification of existing solutions. Over 30 topologies were reviewed, and the main advantages and disadvantages discussed. Applications of isolated matrix inverters are summarized in a tabular form to demonstrate their flexibility for different power and voltage levels achieved due to the presence of a transformer. These inverters have been proposed for the uninterruptible power supplies, high and low-voltage/power photovoltaic systems, low-power fuel cell, different low- and high-voltage battery and/or electric vehicle chargers, audio amplifiers. The fully controlled switches on both terminals of these converters typically can provide the bidirectional power transfer capability, which is also addressed for most of the topologies, but requires some modification in their modulation strategy. Average efficiency of today’s isolated matrix inverters is comparable with the two-stage power converters; however, they can provide higher reliability and lower cost.

2020 ◽  
pp. 29-45
Author(s):  
O.A. Naydis ◽  
I.O. Naydis

The article considers the types, forms, mechanisms and classification of mergers and acquisitions, identifies their positive effects, and studies the tactics of acquisitions. The analysis of anti-capture measures: active and preventive methods of protection against hostile mergers and acquisitions. A comparative analysis of anti-capture measures with acquisitions tactics was carried out, the advantages and disadvantages of their application were identified.


2017 ◽  
Vol 31 (2) ◽  
pp. 82-89
Author(s):  
E. S. Epifanov

This article presents a classification of major factors that shape the cost of Internet site. Also discusses the limitations in determining the objectives of the web site; advantages and disadvantages of different factors.


i-com ◽  
2020 ◽  
Vol 19 (2) ◽  
pp. 67-85
Author(s):  
Matthias Weise ◽  
Raphael Zender ◽  
Ulrike Lucke

AbstractThe selection and manipulation of objects in Virtual Reality face application developers with a substantial challenge as they need to ensure a seamless interaction in three-dimensional space. Assessing the advantages and disadvantages of selection and manipulation techniques in specific scenarios and regarding usability and user experience is a mandatory task to find suitable forms of interaction. In this article, we take a look at the most common issues arising in the interaction with objects in VR. We present a taxonomy allowing the classification of techniques regarding multiple dimensions. The issues are then associated with these dimensions. Furthermore, we analyze the results of a study comparing multiple selection techniques and present a tool allowing developers of VR applications to search for appropriate selection and manipulation techniques and to get scenario dependent suggestions based on the data of the executed study.


2021 ◽  
Vol 11 (5) ◽  
pp. 668
Author(s):  
Sani Saminu ◽  
Guizhi Xu ◽  
Zhang Shuai ◽  
Isselmou Abd El Kader ◽  
Adamu Halilu Jabire ◽  
...  

The benefits of early detection and classification of epileptic seizures in analysis, monitoring and diagnosis for the realization and actualization of computer-aided devices and recent internet of medical things (IoMT) devices can never be overemphasized. The success of these applications largely depends on the accuracy of the detection and classification techniques employed. Several methods have been investigated, proposed and developed over the years. This paper investigates various seizure detection algorithms and classifications in the last decade, including conventional techniques and recent deep learning algorithms. It also discusses epileptiform detection as one of the steps towards advanced diagnoses of disorders of consciousness (DOCs) and their understanding. A performance comparison was carried out on the different algorithms investigated, and their advantages and disadvantages were explored. From our survey, much attention has recently been paid to exploring the efficacy of deep learning algorithms in seizure detection and classification, which are employed in other areas such as image processing and classification. Hybrid deep learning has also been explored, with CNN-RNN being the most popular.


1985 ◽  
Vol 111 ◽  
pp. 411-413
Author(s):  
Janet Rountree ◽  
George Sonneborn ◽  
Robert J. Panek

Previous studies of ultraviolet spectral classification have been insufficient to establish a comprehensive classification system for ultraviolet spectra of early-type stars because of inadequate spectral resolution. We have initiated a new study of ultraviolet spectral classification of B stars using high-dispersion IUE archival data. High-dispersion SWP spectra of MK standards and other B stars are retrieved from the IUE archives and numerically degraded to a uniform resolution of 0.25 or 0.50 Å. The spectra (in the form of plots or photowrites) are then visually examined with the aim of setting up a two-dimensional classification matrix. We follow the method used to create the MK classification system for visual spectra. The purpose of this work is to examine the applicability of the MK system (and in particular, the set of standard stars) in the ultraviolet, and to establish classification criteria in this spectral region.


Author(s):  
K. G. Yashchenkov ◽  
K. S. Dymko ◽  
N. O. Ukhanov ◽  
A. V. Khnykin

The issues of using data analysis methods to find and correct errors in the reports issued by meteorologists are considered. The features of processing various types of meteorological messages are studied. The advantages and disadvantages of existing methods of classification of text information are considered. The classification methods are compared in order to identify the optimal method that will be used in the developed algorithm for analyzing meteorological messages. The prospects of using each of the methods in the developed algorithm are described. An algorithm for processing the source data is proposed, which consists in using syntactic and logical analysis to preclean the data from various kinds of noise and determine format errors for each type of message. After preliminary preparation the classification method correlates the received set of message characteristics with the previously trained model to determine the error of the current weather report and output the corresponding message to the operator in real time. The software tools used in the algorithm development and implementation processes are described. A complete description of the process of processing a meteorological message is presented from the moment when the message is entered in a text editor until the message is sent to the international weather message exchange service. The developed software is demonstrated, in which the proposed algorithm is implemented, which allows to improve the quality of messages and, as a result, the quality of meteorological forecasts. The results of the implementation of the new algorithm are described by comparing the number of messages containing various types of errors before the implementation of the algorithm and after the implementation.


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