JZ

J. Zhao

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19 records found

Conference paper (2025) - N. Akram, J. Zhao, E. Verschuur, N. Savva
With a focus on geo-imaging applications for the energy transition, we are looking for affordable, but still accurate seismic imaging methodologies. One of those recently developed methods is Joint Migration Inversion, which involves the joint estimation of the seismic reflectivity image and the background propagation velocity model. This method operates in the frequency domain and is based on recursive wavefield propagation, while including all scattering and transmission effects. The involved full wavefield modeling engine is the most time-consuming part of the JMI process, so accelerating this has direct impact on the overall costs. One option is making use of the fact that the modeling can be done independently per frequency component, such that we can model the data for a subset of these frequencies and use interpolation to obtain the data at missing frequencies. This papers studies the use of a neural network (NN) approach for this interpolation process. We investigate the accuracy of the interpolation process under different sub-sampling ratios and using regular or irregular subsampling. The counter-intuitive result is that regular subsampling gives slightly better results. Moreover, we demonstrate that we can go down to 66% missing frequencies with the currently used NN based on the cGAN approach. ...
Conference paper (2024) - F. R.Segundo Sevilla, Y. Liu, E. Barocio, P. Korba, A. Zamora, D. Dotta, F. Bellizio, J. Cremer, J. Zhao, More authors...
This paper summarizes recent advancements on spatio-temporal data-driven and machine learning methods for static and dynamic security assessment, and their particular use cases. It is a collective effort of different research groups members of the IEEE Working Group on Big Data Analytics for Transmission Systems, to provide transmission system operators (TSOs) with innovative tools and ideas for their potential implementation. The algorithms presented here are classified as non-training and training approaches, namely spatio-temporal and machine learning based, considering as input time series from time domain simulations, and or synchrophasor data from wide-area monitoring systems. The efficacy of these algorithms is then evaluated in different IEEE benchmark models and using real system measurements from different countries. ...

Hydrospheric and cryospheric data products

Conference paper (2016) - M. Menenti, L. Jia, H.R. Ghafarian Malamiri, V. Phan Hien, R. Lindenbergh, J. Li, J. Wen, L. Li, J. Zhao, B. Dou, G. Hu, Q. Liu, X. Xin, L. Roupioz, C. Zheng, J. Zhou, Z. Li, R. Faivre
The state of the land surface and the water cycle over the South and East Asia can be determined by space observation. New or significantly improved algorithms have been developed and evaluated against ground measurements. Variables retrieved include land surface properties, i.e. NDVI, LAI, FPAR, albedo, soil moisture, glacier and lake levels. Based on these biophysical parameters derived from microwave and optical remote sensing observations, a hybrid remotely sensed evapotranspiration (ET) estimation model named ETMonitor was developed and applied to estimate the daily actual ET of the Southeast Asia at a spatial resolution of 1 km. The changes in glaciers and lakes on the Tibetan Plateau, and the drainage links between glaciers and lakes are determined in this climate-sensitive region. ...
Conference paper (2014) - H Tang, J Zhao, B Li, SYY Leung, CCA Yuan, GQ Zhang
Conference paper (2014) - J Zhao, Y Liu, H Tang, SYY Leung, CCA Yuan, GQ Zhang
Journal article (2013) - Z Zhang, ACA Delsing, PHL Notten, J Zhao, P Dorenbos, HT Hintzen
Journal article (2013) - Z Zhang, OM ten Kate, HT Hintzen, ACA Delsing, Z. Man, R. Xie, Y Shen, MJH Stevens, PHL Notten, P Dorenbos, J Zhao
Journal article (2012) - Z Zhang, OM ten Kate, ACA Delsing, MJH Stevens, J Zhao, PHL Notten, P Dorenbos, HT Hintzen
Conference paper (2008) - CP Pabón-Pereira, J Zhao, B Elmekci, G Zeeman, JB van Lier
Journal article (2005) - G Kumaravelu, MM Alkaisi, D Macdonald, J Zhao, B Rong, A Bittar
Journal article (1998) - J Zhao, R Abegg, DC Healey, L Lee, E Korkmaz, N Kolb, CDP Levy, J Li, CA Miller, SA Page, R Helmer, AK Opper, AR Berdoz, H Postma, WD Ramsay, J Soukop, GM Stinson, WTH van Oers, AN Zelenski, J Birchall, JR Campbell, CA Davis, PPJ Delheij, L Gan, LG Green, LG Greeniaus