- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Modeling and Simulation of High-Frequency Solar Irradiance
摘要： As the use of solar power as a source of electricity is increasing, so is the interest in modeling radiation at high temporal resolutions. High-dimensional remote sensing data products depend on cloud cover variability, atmosphere aerosol levels, and other atmospheric parameters. Because of weather fronts and aerosols, it is difficult to quantify solar power variability based on distributed solar networks. The global horizontal irradiance (GHI) component in the National Solar Radiation Database (NSRDB) is available at a 30-min time resolution. The algorithm proposed in this paper produces 1-min-resolution GHI samples at locations where NSRDB data are available. The synthetic irradiance datasets are produced using log-additive non-Gaussian mixture models and resampling techniques. The model is trained over historical data, and predicted values are compared with in situ data. This approach allows for estimating the solar irradiance at subhourly temporal resolutions, while featuring variability for locations where measurements are otherwise not available.
关键词： irradiance generation,stochastic modeling,mixture distribution,Downscaling
更新于2025-09-04 15:30:14
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[IEEE 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Austin, TX, USA (2018.9.24-2018.9.26)] 2018 International Conference on Simulation of Semiconductor Processes and Devices (SISPAD) - Emerging Memory Modeling Challenges (Invited Paper)
摘要： Emerging Memory (EM) is a broad class of memory devices leveraging a wide spectrum of physical phenomena and/or material properties, that go beyond the charge storage concept of more conventional NAND and DRAM technologies. Availability of physical models and simulation tools to understand their behavior, predict performance, engineer materials and cell architecture would be extremely useful for their successful development. However, such tools are not always available because of the diversity and complexity of the physical mechanisms. This paper would like to review the main trends of the on-going modeling and simulation activities in the field of EM, trying to point out what are the needs and challenges for the future.
关键词： Modeling,Phase Change Memory,Simulation,Resistive RAM,Emerging Memory,Spin Transfer Torque Magnetic RAM
更新于2025-09-04 15:30:14
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DukeSim: A realistic, rapid, and scanner-specific simulation framework in computed tomography
摘要： The purpose of this study was to develop a CT simulation platform that is 1) compatible with voxel-based computational phantoms, 2) capable of modeling the geometry and physics of commercial CT scanners, and 3) computationally efficient. Such a simulation platform is designed to enable the virtual evaluation and optimization of CT protocols and parameters for achieving a targeted image quality while reducing radiation dose. Given a voxelized computational phantom and a parameter file describing the desired scanner and protocol, the developed platform DukeSim calculates projection images using a combination of ray-tracing and Monte Carlo techniques. DukeSim includes detailed models for the detector quantum efficiency, quantum and electronic noise, detector crosstalk, subsampling of the detector and focal spot areas, focal spot wobbling, and the bowtie filter. DukeSim was accelerated using GPU computing. The platform was validated using physical and computational versions of a phantom (Mercury phantom). Clinical and simulated CT scans of the phantom were acquired at multiple dose levels using a commercial CT scanner (Somatom Definition Flash; Siemens Healthcare). The real and simulated images were compared in terms of image contrast, noise magnitude, noise texture, and spatial resolution. The relative error between the clinical and simulated images was less than 1.4%, 0.5%, 2.6%, and 3%, for image contrast, noise magnitude, noise texture, and spatial resolution, respectively, demonstrating the high realism of DukeSim. The runtime, dependent on the imaging task and the hardware, was approximately 2-3 minutes per rotation in our study using a computer with 4 GPUs. DukeSim, when combined with realistic human phantoms, provides the necessary toolset with which to perform large-scale and realistic virtual clinical trials in a patient and scanner-specific manner.
关键词： simulation,ray tracing,monte carlo,computational human phantoms,computed tomography,virtual clinical trial,in silico modeling,CT simulator
更新于2025-09-04 15:30:14
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A Spectral Assignment-Oriented Approach to Improve Interpretability and Accuracy of Proxy Spectral-Based Models
摘要： In modeling chemical attributes using hyperspectral data, nonlinear relationships between the predictor and the response are frequent. The common nonlinear modeling techniques improve prediction accuracy but suffer from low interpretability of the models. In this paper, we demonstrate a new multivariate modeling method, denoted as spectral assignment-oriented partial least squares (SAO-PLS), which is designed to provide a nonlinear modeling solution with strong interpretability products. The need for this approach is apparent when a given sample population consists of different spectral features for different levels of the response. Accordingly, the suggested SAO-PLS algorithm segments the data in an optimal location on the response distribution by maximizing the difference in spectral assignments between two clusters. SAO-PLS is applied here to two test cases with different characteristics: 1) an established data set containing airborne hyperspectral data of asphaltic roads, merged with in situ measured dynamic friction values captured using a standardized method and 2) a soil spectral library, spectrally measured with an analytical spectral device spectrometer, to which organic carbon measurements were applied. Our results demonstrate the superiority of SAO-PLS over partial least-squares regression for both model accuracy and interpretability, providing a deeper understanding of the underlying processes.
关键词： proxy models,Chemometrics,remote sensing,hyperspectral data,nonlinear modeling
更新于2025-09-04 15:30:14
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Electron Transport in Nanoporous Graphene: Probing the Talbot Effect
摘要： Electrons in graphene can show diffraction and interference phenomena fully analogous to light thanks to their Dirac-like energy dispersion. However, it is not clear how this optical analogy persists in nanostructured graphene, for example, with pores. Nanoporous graphene (NPG) consisting of linked graphene nanoribbons has recently been fabricated using molecular precursors and bottom-up assembly (Moreno et al. Science 2018, 360, 199). We predict that electrons propagating in NPG exhibit the interference Talbot effect, analogous to photons in coupled waveguides. Our results are obtained by parameter-free atomistic calculations of real-sized NPG samples based on seamlessly integrated density functional theory and tight-binding regions. We link the origins of this interference phenomenon to the band structure of the NPG. Most importantly, we demonstrate how the Talbot effect may be detected experimentally using dual-probe scanning tunneling microscopy. Talbot interference of electron waves in NPG or other related materials may open up new opportunities for future quantum electronics, computing, or sensing.
关键词： multiscale modeling,electron transport,Nanoporous graphene,scanning probe microscopy,Talbot interference
更新于2025-09-04 15:30:14
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Fast gas heating of nanosecond pulsed surface dielectric barrier discharge: Spatial distribution and fractional contribution from kinetics
摘要： The effect of heat release in reaction with charged and electronically excited species, or so-called fast gas heating (FGH) in nanosecond surface dielectric barrier discharge (nSDBD) in atmospheric pressure air is studied. 2D numerical simulations based on PASSKEy code (PArallel Streamer Solver with KinEtics code) are conducted. The code is based on the direct coupling of a self-consistent fluid model with detailed kinetics, an efficient photo-ionization model and Euler equations. The choice of local field approximation for nSDBD modeling with simplified kinetics is discussed. The reduced electric field and the electron density are examined at both polarities for the identical high-voltage pulses 24 kV in amplitude on the high voltage electrode and 20 ns FWHM. The distribution of the fast gas heating energy and the resulting gas temperature field are studied and compared with existing references. The input of different reactions to appearing hydrodynamic perturbations is analyzed.
关键词： nanosecond surface dielectric barrier discharge,plasma modeling,fast gas heating,nSDBD
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Atlanta, GA, USA (2018.10.31-2018.11.2)] 2018 IEEE 6th Workshop on Wide Bandgap Power Devices and Applications (WiPDA) - Experimental Comparison of the Efficiency, Power Density and Thermal Performance of Two BIPV Converter Prototypes
摘要： This paper presents an experimental comparison between two series resonant full bridge converters for use in BIPV applications. The first converter employs Si MOSFETS and the second converter uses GaN HEMTs for the switches of the full bridge. The practical implementation and design of the boards and the trade-offs between components are highlighted. The efficiency, power density and thermal performance of the converters are discussed in detail. Practical issues, such as secondary oscillatory behaviour, in the development of a phase-shifted full bridge are highlighted. The used transformer is modeled, including all parasitic elements. Several solutions to avoid transient oscillations in the secondary are set forward. To mitigate these high-frequency voltage transient overshoots, the best solution was found to equip the primary of the converter with a series resonant tank.
关键词： transformer modeling,GaN,BIPV,resonant conversion
更新于2025-09-04 15:30:14
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[IEEE 2018 IEEE 19th Workshop on Control and Modeling for Power Electronics (COMPEL) - Padua (2018.6.25-2018.6.28)] 2018 IEEE 19th Workshop on Control and Modeling for Power Electronics (COMPEL) - Characterization and Modeling of the Impact of the Substrate Potential in the Dynamic and Static Behavior of Power GaN-on-Si HEMTs
摘要： The maturity of GaN power transistors grown on conductive Si substrates permits today the integration of gate drivers and half bridges in a monolithic integrated chip. Among others, the back-gating effect arising from the substrate potential poses a challenge for circuit designers and hinders the development of this promising technology. In this paper, we characterize the effect of the substrate potential in the IV characteristics of a commercially available GaN power HEMT. A modified version of the ASM-HEMT compact transistor model which accounts for the effect of the substrate potential on IV and part of the CV characteristics is extracted from these measurements. Through transient simulations of the fitted transistor model, the impact of the bulk potential in the dynamic and static characteristics of power GaN-on-Si HEMTs is investigated.
关键词： substrate potential,power semiconductor device,semiconductor device modeling,Gallium Nitride,current-voltage characteristics,HEMTs
更新于2025-09-04 15:30:14