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A CUDA-based GPU engine for gprMax: Open source FDTD electromagnetic simulation software
摘要： The Finite-Difference Time-Domain (FDTD) method is a popular numerical modelling technique in computational electromagnetics. The volumetric nature of the FDTD technique means simulations often require extensive computational resources (both processing time and memory). The simulation of Ground Penetrating Radar (GPR) is one such challenge, where the GPR transducer, subsurface/structure, and targets must all be included in the model, and must all be adequately discretised. Additionally, forward simulations of GPR can necessitate hundreds of models with different geometries (A-scans) to be executed. This is exacerbated by an order of magnitude when solving the inverse GPR problem or when using forward models to train machine learning algorithms. We have developed one of the first open source GPU-accelerated FDTD solvers specifically focussed on modelling GPR. We designed optimal kernels for GPU execution using NVIDIA’s CUDA framework. Our GPU solver achieved performance throughputs of up to 1194 Mcells/s and 3405 Mcells/s on NVIDIA Kepler and Pascal architectures, respectively. This is up to 30 times faster than the parallelised (OpenMP) CPU solver can achieve on a commonly-used desktop CPU (Intel Core i7-4790K). We found the cost-performance benefit of the NVIDIA GeForce-series Pascal-based GPUs – targeted towards the gaming market – to be especially notable, potentially allowing many individuals to benefit from this work using commodity workstations. We also note that the equivalent Tesla-series P100 GPU – targeted towards data-centre usage – demonstrates significant overall performance advantages due to its use of high-bandwidth memory. The performance benefits of our GPU-accelerated solver were demonstrated in a GPR environment by running a large-scale, realistic (including dispersive media, rough surface topography, and detailed antenna model) simulation of a buried anti-personnel landmine scenario.
关键词： GPGPU,Finite-Difference Time-Domain,GPU,CUDA,GPR,NVIDIA
更新于2025-09-11 14:15:04
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One-Step Leapfrog ADI-FDTD Method Using the Complex-Conjugate Pole-Residue Pairs Dispersion Model
摘要： A novel one-step leapfrog alternating-direction-implicit finite-difference time-domain method for the modeling of dispersive media described by the complex-conjugate pole-residue pairs model is proposed. The efficiency of the technique is demonstrated in benchmark numerical examples.
关键词： finite-difference time-domain (FDTD) method,leapfrog alternating-direction-implicit (LADI) scheme,Dispersive media
更新于2025-09-11 14:15:04
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[IEEE 2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO) - Reykjavik, Iceland (2018.8.8-2018.8.10)] 2018 IEEE MTT-S International Conference on Numerical Electromagnetic and Multiphysics Modeling and Optimization (NEMO) - Concept of a Complex Envelope Faber Polynomial Approach for the Solution of Maxwell’s Equations
摘要： We investigate a novel complex envelope approach for the numerical solution of Maxwell’s equations based on the time domain propagator using Faber the expansion of polynomials. Due to the application of the complex envelope only the envelope of the investigated fields has to be simulated. This offers promising prospects with respect to the application of larger time steps. The properties of the Faber polynomials enable a flexible and a highly accurate approximation of the time domain propagator what offers interesting prospects for the analysis of devices in the fields of THz technology and photonics.
关键词： Electromagnetic propagation,finite-difference time-domain (FDTD) methods
更新于2025-09-11 14:15:04
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Novel FDTD Scheme for Analysis of Frequency-Dependent Medium Using Fast Inverse Laplace Transform and Prony’s Method
摘要： A novel finite-difference time-domain (FDTD) approach is proposed for analysis of wave propagation in a general frequency-dependent medium. In the proposed method, formulation of the fractional derivatives in the time-domain representation is circumvented by using the fast inverse Laplace transform (FILT) and Prony’s method. The FILT is used to transform the dispersion expressed in a frequency domain into a time-domain response and Prony’s method is utilized to extract parameters and transform the time-domain responses into those in the z-domain so that they can be incorporated into the FDTD method directly. The update equation of the electric field in the FDTD method is then formulated by using the z-transformation. Stability analysis of the proposed scheme is also investigated by means of the root-locus method. Reflection coefficients of dispersive media, such as Debye, Cole–Cole, Davidson–Cole, and Havriliak–Negami media simulated in a one-dimensional domain and a three-layered biological medium of skin, fat, and muscle tissues inside a waveguide with a TE10 fundamental mode in a two-dimensional domain, are found to be in good agreement with those obtained by an analytical method over a broad frequency range, demonstrating validity of the proposed FDTD scheme.
关键词： Prony’s method,time-domain method,Cole–Cole medium,FDTD,Finite-difference,Laplace transform,frequency-dependent medium
更新于2025-09-11 14:15:04
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Analysis of Electromagnetic Wave Propagation in Variable Magnetized Plasma via Polynomial Chaos Expansion
摘要： A three-dimensional stochastic FDTD algorithm is developed and applied to electromagnetic wave propagation in collisional magnetized plasma characterized by a variable electron density, collision frequency, and background magnetic ?eld. The proposed stochastic model is based on the expansion of the random / variable time-domain electric and magnetic ?elds in terms of orthogonal polynomials in independent random variables representative of the variable ionospheric content. Electromagnetic wave propagation in magnetized plasma having low variability (small deviations) and also high variability (large deviations) of the electron density, collision frequency, and background magnetic ?eld is studied. The stochastic algorithm is validated against brute-force Monte Carlo results. The algorithm is considerably more computationally ef?cient than Monte Carlo. When applied to electromagnetic wave propagation in the ionosphere, the variability of the Earth’s magnetic ?eld and ionospheric parameters can be accounted for due to naturally varying space weather conditions and day-to-day variations, measurement errors, etc. Although only electrons are considered here, positive and negative ions may be accommodated in a straight-forward manner.
关键词： ?nite-difference time-domain (FDTD),electromagnetic wave propagation,ionosphere,polynomial chaos,uncertainty,collisional magnetized cold plasma
更新于2025-09-11 14:15:04
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[IEEE 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Honolulu, HI, USA (2018.7.18-2018.7.21)] 2018 40th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - Reliability of Short-Term Heart Rate Variability Indexes Assessed through Photoplethysmography
摘要： The gold standard method to monitor heart rate variability (HRV) comprises measuring the time series of interbeat interval durations from electrocardiographic (ECG) recordings. However, due to the widespread use, simplicity and usability of photoplethysmographic (PPG) techniques, monitoring pulse rate variability (PRV) from pulse wave recordings has become a viable alternative to standard HRV analysis. The present study investigates the accuracy of PRV, measured as a surrogate of HRV, for the quantification of descriptive indexes computed in the time domain (mean, variance), frequency domain (low-to-high frequency power ratio LF/HF, HF band central frequency) and information domain (entropy, conditional entropy). We analyze short time series (300 intervals) of HRV measured from the ECG and of PRV acquired from Finometer device in 76 subjects monitored in the resting supine position (SU) and in the upright position during head-up tilt (HUT). Time, frequency and information domain indexes are computed for each HRV and PRV series and, for each index, the comparison between the two approaches is performed through statistical comparison of the distributions across subjects, robust linear regression, and Bland-Altman plots. Results of the comparison indicate an overall good agreement between PRV-based and HRV-based indexes, with an accuracy that is slightly lower during HUT than during SU, and for the band-power ratio and conditional entropy. These results suggest the feasibility of PRV-based assessment of HRV descriptive indexes, and suggest to further investigate the agreement in conditions of physiological stress.
关键词： information domain,photoplethysmography,time domain,pulse rate variability,frequency domain,heart rate variability
更新于2025-09-10 09:29:36
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Time-Division Parallel FDTD Algorithm
摘要： We propose a novel and efficient algorithm to parallelize the finite-difference time-domain method, where the observation period is divided into an arbitrary number of subsections, whose computation is distributed to corresponding computer nodes. The proposed algorithm roughly reduces the computational time to an n-th fraction of the conventional algorithm, where n is the number of nodes for parallel computing, thus verifying its efficiency improvement.
关键词： finite-difference complex-frequency-domain method,fast inverse Laplace transform,finite-difference time-domain method,time-division parallel algorithm
更新于2025-09-10 09:29:36
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Fast method for analysing nonlinear composite right/left-handed transmission lines based on finite-difference time-domain method
摘要： In this study, a new finite-difference time-domain (FDTD) scheme is presented for analysing nonlinear composite right/left-handed (CRLH) transmission lines, with reduction of the central processing unit time. A step by step analysis is demonstrated to solve the equations for nonlinear CRLH transmission lines based on the FDTD method. The proposed method is applied to a nonlinear CRLH transmission line as an example and the results are confirmed by those of the conventional FDTD method. The comparisons reveal that the presented solution efficiently decreases by about 82% of the computational time consumption.
关键词： finite-difference time-domain (FDTD),computational time reduction,nonlinear composite right/left-handed (CRLH) transmission lines
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Broadband Full Polarimetric Scatterometry for Monitoring Soil Moisture and Vegetation Properties Over a Tibetan Meadow
摘要： A scatterometer is installed on a meadow over the Tibetan Plateau in August 2017 to measure the full polarimetric backscattering coefficient ??0 over a wide frequency range (1 - 10 GHz) year-round. In this paper we describe the setup of scatterometer as well as the activities undertaken to test the reliability of the system. The measured radar cross section of a dihedral reflector matches the theoretical model for 3 – 10 GHz after the calibration. The temperature-induced systematic error in the radar return will be accounted for by using the antenna cross coupling as a reference. For the retrieval of ?0 the frequency-dependent antenna radiation pattern and the site geometry are accounted for. Fading will be dealt with by using frequency agility techniques.
关键词： Radar cross section calibration,Time-domain gating,Tibetan Plateau,Broadband,Scatterometer
更新于2025-09-10 09:29:36
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A sensor detecting kissing bonds in adhesively bonded joints using electric time domain reflectometry
摘要： The joining technology with the highest potential in lightweight construction is the adhesive bonding. In an adhesively bonded joint different defects can occur. Alongside gross defects like areas of uncured adhesive and voids, adhesion defects like kissing bonds pose a serious problem to the confidence in these kind of joints in the aircraft industry and other industries. Since kissing bonds are small interfacial defects of as few as nanometers in thickness, the detection by conventional nondestructive testing methods is not possible in most applications. In this paper a novel adhesive sensor based on the electric time domain reflectometry is proposed detecting differences in the deformation of the adherents in an adhesively bonded joint to infer that a kissing bond is taking affect. Numerical calculations are used to show that the proposed sensor principle poses a productive approach. For the numerical calculations a finite difference time domain model is used. The sensor is then validated experimentally by shear tension testing of single lap shear specimens with the adhesive sensor integrated into the joint.
关键词： Kissing bond,Fiber reinforced plastics,Digital image correlation,Non-destructive testing,Adhesively bonded joint,Electric time domain reflectometry
更新于2025-09-10 09:29:36