Searched for: author%3A%22Zhang%2C+L.%22
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Zhang, D. (author), Zhang, L. (author), Verschuur, D.J. (author)
Ground penetrating radar (GPR) is a commonly used technology for identifying and examining ice. The low electrical conductivity and the uniformity of ice covers provide GPR with exceptional signal penetration and, thus, the ability to reveal the internal layers of glaciers. To extract the necessary information, wavefield separation and imaging...
conference paper 2024
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Zhang, L. (author), Han, S. (author), Grammatico, S. (author)
In this paper, we propose a novel behavior planner that combines game theory with search-based planning for automated lane merging. Specifically, inspired by human drivers, we model the interaction between vehicles as a gap selection process. To overcome the challenge of multi-modal behavior exhibited by the surrounding vehicles, we formulate...
conference paper 2023
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Zhang, L. (author), Zhang, Y. (author), van Keulen, A. (author)
High computational costs are encountered in topology optimization problems of geometrically nonlinear structures since intensive use has to be made of incremental-iterative finite element simulations. To alleviate this computational intensity, reduced-order models (ROMs) are explored in this paper. The proposed method targets ROM bases...
journal article 2023
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Zhang, L. (author), Babaie, M. (author)
Digital beamforming receivers (RXs) support MIMO operation and offer great flexibility and accuracy in multi-beam formation and calibration. However, compared with analog phased-array and hybrid systems, due to the absence of any rejection for spatial in-band blockers, the RX/ADC dynamic range and linearity should be high enough to prevent...
conference paper 2022
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Zhang, L. (author), Shen, Y. (author), de Vreede, L.C.N. (author), Babaie, M. (author)
This letter presents a millimeter-wave (mm-wave) vector-modulated phase shifter (VMPS) for phased-array applications. To improve the phase-shift accuracy without drastically increasing design complexity, the proposed VMPS structure employs variable-gain amplifiers (VGAs) that offer 2× better resolution at their low-gain...
journal article 2022
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Zhang, Youming (author), Wei, Zhennan (author), Tang, Xusheng (author), Zhang, L. (author), Huang, Fengyi (author)
This letter presents a convenient approach based on the two-port kQ-product theory to analyze the influence of interwinding capacitive coupling on the efficiency of the transformer. It is demonstrated that a transformer with proper size can benefit from the interwinding capacitive coupling to maximize its efficiency at a desired frequency....
journal article 2022
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Zhang, L. (author), Shao, Jie (author), Zheng, Yikang (author), Wang, Y. (author), Slob, E.C. (author)
Marchenko imaging can be seen as an internal multiple elimination scheme in imaging domain. By solving coupled Marchenko equations, the measured seismic data can be correctly redatumed to the subsurface with source positioned at subsurface and receivers positioned at acquisition surface. Then, the artefact-free image of the source point can...
journal article 2022
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van der Neut, J.R. (author), Brackenhoff, J.A. (author), Meles, G.A. (author), Zhang, L. (author), Slob, E.C. (author), Wapenaar, C.P.A. (author)
A Green's function in an acoustic medium can be retrieved from reflection data by solving a multidimensional Marchenko equation. This procedure requires a priori knowledge of the initial focusing function, which can be interpreted as the inverse of a transmitted wavefield as it would propagate through the medium, excluding (multiply)...
journal article 2022
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van der Neut, J.R. (author), Brackenhoff, J. (author), Meles, G. (author), Zhang, L. (author), Slob, E.C. (author), Wapenaar, C.P.A. (author)
Green’s functions in an unknown medium can be retrieved from single-sided reflection data by solving a multidimensional Marchenko equation. This methodology requires knowledge of the direct wavefield throughout the medium, which should include forward-scattered waveforms. In practice, the direct field is often computed in a smooth background...
conference paper 2021
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Slob, E.C. (author), Zhang, L. (author), Verschuur, D.J. (author)
Marchenko multiple elimination schemes are able to attenuate all internal multiple reflections in acoustic reflection data. These can be implemented with and without compensation for two-way transmission effects in the resulting primary reflection data set. The methods are fully automated and run without human intervention, but they require the...
journal article 2021
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Wapenaar, C.P.A. (author), Brackenhoff, J.A. (author), Dukalski, Marcin (author), Meles, G.A. (author), Slob, E.C. (author), Staring, M. (author), Thorbecke, J.W. (author), van der Neut, J.R. (author), Zhang, L. (author), Reinicke Urruticoechea, C. (author)
With the Marchenko method it is possible to retrieve Green's functions between virtual sources in the subsurface and receivers at the surface from reflection data at the surface and focusing functions. A macro model of the subsurface is needed to estimate the first arrival; the internal multiples are retrieved entirely from the reflection data....
journal article 2021
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Slob, E.C. (author), Zhang, L. (author)
Migration, velocity and amplitude analysis are the employed processing steps to find the desired subsurface information from seismic reflection data. The presence of free-surface and internal multiples can mask the primary reflections for which many processing methods are built. The ability to separate primary from multiple reflections is...
journal article 2021
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Bakker, Coen (author), Zhang, L. (author), Higginson, Kristie (author), van Keulen, A. (author)
Stiffened shells and plates are widely used in engineering. Their performance is highly influenced by the arrangement, or layout, of stiffeners on the base shell or plate and the geometric features, or topology, of these stiffeners. Moreover, modular design is beneficial, since it allows for increased quality control and mass production. In...
journal article 2021
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Thorbecke, J.W. (author), Zhang, L. (author), Wapenaar, C.P.A. (author), Slob, E.C. (author)
The Marchenko multiple elimination (MME) and transmission compensation schemes retrieve primary reflections in the two-way traveltime domain without model information or using adaptive subtraction. Both schemes are derived from projected Marchenko equations and are similar to each other, but they use different time-domain truncation operators...
journal article 2021
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Peng, Haorui (author), Vasconcelos, Ivan (author), Sripanich, Yanadet (author), Zhang, L. (author)
Marchenko methods can retrieve both Green’s functions and focusing functions from single-sided reflection data and a smooth velocity model, as essential components of a redatuming process. Recent studies also show that a modified Marchenko scheme can reconstruct primary-only reflection responses directly from reflection data without requiring a...
journal article 2021
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Slob, E.C. (author), Zhang, L. (author)
The ability to separate primary reflections from multiples is important for making subsurface images. Many existing methods need some form of model information and adaptive subtraction. Marchenko methods have been modified to operate at the acquisition surface. The associated filters can be computed from the reflection response without any model...
conference paper 2020
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Slob, E.C. (author), Zhang, L. (author)
Marchenko methods compute a focusing function for a receiver at the acquisition surface and a virtual source in the subsurface. Computing the focusing function requires subsurface information. The method has been modified to operate at the acquisition surface. The focusing function becomes a fundamental wave field as known since many decades....
conference paper 2020
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Zhang, L. (author), Hung, H.S. (author)
In this paper, we carry out an extensive study of social involvement in free standing conversing groups (the so-called F-formations) from static images. By introducing a novel feature representation, we show that the standard features which have been used to represent full membership in an F-formation cannot be applied to the detection of so...
journal article 2020
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Staring, M. (author), Zhang, L. (author), Thorbecke, J.W. (author), Wapenaar, C.P.A. (author)
We have seen many developments in Marchenko equation-based methods for internal multiple attenuation in the past years. Starting from a wave-equation based method that required a smooth velocity model, there are now Marchenko equation-based methods that do not require any model information or user-input. In principle, these methods accurately...
conference paper 2020
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Meles, G.A. (author), Zhang, L. (author), Thorbecke, J.W. (author), Wapenaar, C.P.A. (author), Slob, E.C. (author)
Seismic images provided by reverse time migration can be contaminated by artefacts associated with the migration of multiples. Multiples can corrupt seismic images, producing both false positives, that is by focusing energy at unphysical interfaces, and false negatives, that is by destructively interfering with primaries. Multiple prediction...
journal article 2020
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