In order to improve the prediction accuracy and robustness of radio wave propagation in very high-frequency (VHF) band, we proposed a combination model (CPM) based on entropy weight theory machine learning method. The improved method is used determine initial weights recommendation ITU-R P.1546 P.2001 CPM systematic analysis performance two models. Instead, modeled mapping using statistical comparison shows that are better than models, which root-mean-square error (RMSE) path loss reduced by...

ABSTRACT In high‐voltage feedback applications with small LC filter capacitor equivalent series resistance (ESR), the synchronous sampling process will introduce aliasing, produce low‐frequency distortion, and deteriorate power quality. At same time, there is an inherent 1.5‐beat delay, which limits control bandwidth, resulting in a system stability area insufficient response time. Shifting instant can reduce delay. However, aliasing occur if improperly selected. Previous studies have not...

Today’s highly complex and rapidly changing electromagnetic environment places higher demands on the precise localization of illegal radiation sources. In response to this, this paper innovatively proposes a multi-station fusion-based source method, which leverages frequency, field strength, bandwidth, other characteristic information embedded in frequency band scanning data. The method thoroughly explores energy characteristics detected sources while closely integrating objective laws...

Abstract VHF and UHF are widely used frequency bands, accurate path loss prediction in these bands is of great significance. In order to improve the accuracy stability radio wave propagation, we propose a combined modeling method based on entropy weight method. This assigns appropriate weights predicted values sub‐models using entropy, calculates final value through weighted aggregation. To validate feasibility our proposed method, conduct data from Denver, Colorado. We compare with ITU‐R...

In low-voltage applications using low-Q LC filters, alias-free capacitor voltage acquisition can be achieved, but synchronous sampling under high-Q filters used in high-voltage grid-forming converters causes some degree of distortion and results degradation the power supply quality. And 1.5 beat delay inherent this approach limits control bandwidth, reduces stability region, an inadequate time domain response. Despite these shortcomings, is widely accepted practice. This paper concludes that...

For improving the accuracy and robustness of predicting radio propagation in frequency bands FM Broadcasting Services, we proposed a prediction model suitable for multi-band multi-scenario based on Support Vector Regression (SVR). The modeling is Beijing's measurement data, covering various environments, such as rural, suburban, urban areas, with range 86.7MHz-106.6MHz. A comparison will be made to verify model's performance ITU-R P.1546 model, an internationally common recommended by ITU....

The radio channel model is a major factor supporting the whole life cycle of terrestrial system, including demonstration, design, validation, operation, and so on. To improve spectrum sharing spectral efficiency in services, we analyze three types path loss models detail: deterministic, empirical, semi-empirical models, to meet requirements modeling for traditional band expansion reuse. Then, conduct comparative analysis based on characteristics current models. Furthermore, preview future...

Abstract To master the electromagnetic environment characteristics around Five-hundred-meter Aperture Spherical radio Telescope (FAST) and ensure a better ecological in radio-quiet zone of FAST, we analyzed radiation public communication stations FAST. By comparing FAST received signal power from interference protection threshold astronomy applications, found that total proportion exceeding is 69.01%. Furthermore, to fully protect regular operation proposed four avoidance frequency...

In this study, we aim to analyze the electromagnetic interference (EMI) regarding Five-hundred-meter Aperture Spherical radio Telescope (FAST) caused by base stations in International Mobile Telecommunications-2000 (IMT-2000) frequency band. By analyzing bands used transmitting and receiving devices surrounding environmental parameters utilizing an approach predicting wave propagation loss that is based on deterministic methods, conclude comparing predicted received power at FAST with its...

Epileptic seizures have a serious impact on the normal life of patients with epilepsy. seizure prediction can effectively reduce mental pressure epilepsy and improve patients' quality life. It is key challenging task to predict from Electroencephalogram (EEG) data collected by EEG acquisition devices. To accuracy epileptic prediction, this paper proposes method based synthetic signals Generative Pre-Training (GPT). The generated added into actual data, which improves prediction. In...

With the development of photovoltaic industry, there will be an increasing demand for efficient, high-power density, and low-cost grid interface converters. Compared with two-level inverters, multilevel inverters have following advantages: (1) lower device voltage ratings; (2) better output filtering spectrum; (3) electromagnetic interference (EMI) noise; (4) higher switching speed capability. However, complex circuit inverter bring more parasitic inductance, resulting in serious overvoltage...

With the development of photovoltaic industry; there will be an increasing demand for efficient, high-power density, and low-cost grid interface converters. Compared with two-level inverters, multilevel inverters have following advantages: (1) lower device voltage ratings; (2) better output filtering spectrum; (3) electromagnetic interference (EMI) noise; (4) higher switching speed capability. However, complex circuit inverter bring more parasitic inductance, resulting in severe overvoltage...

Abstract Palladium (Pd)-based sulfides have triggered extensive interest due to their unique properties and potential applications in the fields of electronics optoelectronics. However, synthesis large-scale uniform PdS 2 nanofilms (NFs) remains an enormous challenge. In this work, 2-inch wafer-scale NFs with excellent stability can be controllably prepared via chemical vapor deposition combined electron beam evaporation technique. The thickness pre-deposited Pd film sulfurization...

This study presents an innovative control framework designed for voltage source inverters (VSIs) equipped with LC output filters. The primary objective of this structure is to reduce delay and suppress aliasing by employing a double-loop univariate active damping strategy.The stability the system degraded because limits bandwidth system.It has been shown that although multisampling method can effectively delay,it also suffers from problems pulse loss multiple comparisons, which leads...

ABSTRACT In low‐voltage applications using low‐Q LC filters, alias‐free capacitor voltage acquisition can be achieved, but synchronous sampling under high‐Q filters used in high‐voltage grid‐forming converters causes some degree of distortion and results degradation the power supply quality. And inherent 1.5 periods that delay this approach limit control bandwidth, reduce stability region, result an inadequate time domain response. Despite these shortcomings, is widely accepted practice. The...

Abstract Selenium (Se), as a typical elemental semiconductor, has garnered significant attention due to its excellent carrier mobility, outstanding photoconductivity, and broad spectral response. However, Se micro‐ nanostructures exhibit inherently low nonlinear optical coefficients, necessitating substantial enhancement of their properties. In this study, trigonal (t‐Se) microwires (MWs) t‐Se/MoS 2 mixed‐dimensional vertical heterostructures are synthesized using the atmospheric pressure...

ABSTRACT This study presents an innovative control framework designed for voltage source inverters (VSIs) equipped with LC output filters. The objective of this is to reduce delay and suppress aliasing effects by employing multisampling techniques implementing repetitive filtering methods. approach can significantly delays, thereby enhancing both the bandwidth stability margins system. implementation inverter enhance dynamic performance. However, it may introduce high‐frequency ripples in...

PLC, abbreviation for power line communication technology, is the use of existing low voltage distribution network as a transmission medium to transfer data and exchange information. In order realize high speed Internet access multimedia information by using line, in this paper, Ethernet adapter researched improved taking advantage 220V/380V line. Firstly, OFDM modulation technology analyzed simulated Matlab partially, then INT6400 chosen main control chip, additionally, bandpass filter an...