Publications by Hamidreza Karami

Chat with Graph Search

Ask any question about EPFL courses, lectures, exercises, research, news, etc. or try the example questions below.

DISCLAIMER: The Graph Chatbot is not programmed to provide explicit or categorical answers to your questions. Rather, it transforms your questions into API requests that are distributed across the various IT services officially administered by EPFL. Its purpose is solely to collect and recommend relevant references to content that you can explore to help you answer your questions.

The localization of partial discharges (PD) is important to monitor the conditioning of high voltage insulator materials. One of the key components in power grids is the high power transformer. Localization of PDs in these pieces of equipment can increase ...

Source reconstruction methods have many applications such as antenna diagnosis, calculating far-field radiated emissions, and identifying incompatible sources on integrated circuits or printed circuit boards. In this paper, the Gerchberg-Saxton algorithm i ...

In this paper, the impact of an increasing number of arbitrary electrical/electronic devices on the overall radiated emissions is investigated. Understanding and quantifying such an impact are prerequisites to the proper evaluation of electromagnetic compa ...

This article presents for the first time an OpenACC (Open accelerators)-aided Graphics Processing Unit (GPU)-based approach adopting a 3D moving window finite difference time domain (MW-FDTD) method for calculating lightning electromagnetic fields over lar ...

The localization of partial discharge (PD) sources is of importance for the monitoring and maintenance of power transformers. Time difference of arrival (TDoA) based methods are widely adopted in the literature for the localization of PDs. Recently, time r ...

In this article, we propose a novel approach for the localization of electromagnetic interference (EMI) sources based on the concept of compressive sensing and metalenses. We show that using the spatial and frequency dispersion offered by the metalens, we ...

In this paper, we present a review and classification of the published works on the use of Electromagnetic Time Reversal (EMTR)-based methods to locate landmines. Different approaches for landmine localization using EMTR are investigated. Specifically, the ...

Recently, a closed time-reversal cavity for electromagnetic waves was demonstrated and experimentally realized using a network of transmission lines. This paper presents an analysis in the frequency domain of the wave propagation characteristics that perta ...

This paper presents a rigorous assessment of natural frequencies associated with fault-originated travelling waves in power networks, factoring in the presence of multiple junctions and branches. The proposed assessment exploits the Baum-Liu-Tesche (BLT) e ...

In recent years, the electromagnetic time reversal (EMTR) theory has been successfully applied for locating various sources of disturbances, such as short-circuit faults, in power systems. In this paper, a theoretical analysis of the feasibility of applyin ...

Electromagnetic Time Reversal (EMTR) has been used to locate different types of electromagnetic sources. We propose a novel technique based on the combination of EMTR and Machine Learning (ML) for source localization. We show for the first time that ML tec ...

In this work, we present a novel technique to locate partial discharge (PD) sources based on the concept of time reversal. The localization of the PD sources is of interest for numerous applications, including the monitoring of power transformers, Gas Insu ...

Time reversal exploits the invariance of electromagnetic wave propagation in reciprocal and lossless media to localize radiating sources. Time-reversed measurements are back-propagated in a simulated domain and converge to the unknown source location. The ...

In this paper, three machine learning (ML)-based approaches—XGBoost, Artificial Neural Network (ANN), and Random Forest algorithms—are compared for the localization of lightning through the analysis of lightninginduced voltages on power transmission lines. ...

We implement an electromagnetic time reversal technique (EMTR) to locate lightning return strokes. The two-dimensional finite difference time domain is employed to simulate the EMTR process in both, the forward-time and the backward-time phases. Scatterers ...

The localization of Electromagnetic Interference (EMI) sources is very important in Electromagnetic Compatibility applications. Recently, a novel localization technique based on the Time Reversal Cavity (TRC) concept was proposed using only one sensor. In ...

An open accelerator (OpenACC)-aided graphics processing unit (GPU)-based finite difference time domain (FDTD) method is presented for the first time for the 3D evaluation of lightning radiated electromagnetic fields along a complex terrain with arbitrary t ...

In this paper, a series of numerical simulations are conducted for various 2D and 3D configurations to demonstrate the performance of the Time Reversal MUltiple SIgnal Classification (TR‐MUSIC) method. The results reveal the excellent performance of TR‐MUS ...

In this paper, the time reversal (TR) technique is extended to localize a partial discharge (PD) source in the acoustic regime. The proposed acoustic TR method consists of three steps, a) the acoustic waves emitted by the PD source are recorded by at least ...

In this paper, for the first time, an experimental proof of concept for utilising time reversal (TR) in the acoustic regime to localise partial discharge (PD) sources was presented using a single sensor. To achieve this, an experimental setup comprising a ...

Hamidreza Karami

Chat with Graph Search

Partial discharge localization in power transformers using acoustic time reversal

Source Reconstruction Method Using Phase-Less Magnetic Near-Field Measurements: Application of the Method of Moment with Roof-Top Basis Functions

EMC Impact of Disturbances Generated by Multiple Sources

Assessing the Efficacy of a GPU-Based MW-FDTD Method for Calculating Lightning Electromagnetic Fields Over Large-Scale Terrains

An experimental validation of partial discharge localization using electromagnetic time reversal

A Compressive Sensing Framework for EMI Source Localization Using a Metalens Structure: Localization Beyond the Diffraction Limit

Landmine Detection Using Electromagnetic Time Reversal-Based Methods: 1. Classical TR, Iterative TR, DORT and TR-MUSIC

A Frequency-Domain Analysis of a Time-Reversal Cavity for Electromagnetic Waves in Transmission Line Networks

Rigorous Assessment of Natural Frequencies of Fault-Originated Travelling Waves

Assessment of the Feasibility of Applying the Electromagnetic Time Reversal Theory to Locate Defects in Grounding Electrodes

Single-Sensor Source Localization Using Electromagnetic Time Reversal and Deep Transfer Learning: Application to Lightning

Partial Discharge Localization Using Time Reversal: Application to Power Transformers

Spatiotemporal energy‐density distribution of time‐reversed electromagnetic fields

An Efficient Machine Learning Model for Lightning Localization via Lightning-Induced Voltages on Transmission Lines

Numerical and Experimental Validation of Electromagnetic Time Reversal for Geolocation of Lightning Strikes

Localization of Electromagnetic Interference Source Using a Time Reversal Cavity: Application of the Maximum Power Criterion

On the Efficiency of OpenACC-aided GPU-Based FDTD Approach: Application to Lightning Electromagnetic Fields

Landmine Detection Using Electromagnetic Time Reversal‐Based Methods: 2. Performance Analysis of TR‐MUSIC

An Acoustic Time Reversal Technique to Locate a Partial Discharge Source: Two-Dimensional Numerical Validation

An experimental proof of concept of time‐reversal single‐sensor acoustic source localisation: Application to partial discharges