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In recent years, one-bit quantization has attracted widespread attention in the field of direction-of-arrival (DOA) estimation as a low-cost and low-power solution. Many researchers have proposed various estimation algorithms for one-bit DOA estimation, among which atomic norm minimization algorithms exhibit particularly attractive performance as gridless estimation algorithms. However, current one-bit DOA algorithms with atomic norm minimization typically rely on approximating the trace function, which is not the optimal approximation and introduces errors, along with resolution limitations. To date, there have been few studies on how to enhance resolution under the framework of one-bit DOA estimation. This paper aims to improve the resolution constraints of one-bit DOA estimation. The log-det heuristic is applied to approximate and solve the atomic norm minimization problem. In particular, a reweighted binary atomic norm minimization with noise assumption constraints is proposed to achieve high-resolution and robust one-bit DOA estimation. Finally, the alternating direction method of multipliers algorithm is employed to solve the established optimization problem. Simulations are conducted to demonstrate that the proposed algorithm can effectively enhance the resolution.
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http://dx.doi.org/10.3390/s24185936 | DOI Listing |
Comput Biol Med
September 2025
Laboratorio de Procesado de Imagen (LPI), ETSI Telecomunicación, Universidad de Valladolid, Valladolid, Spain. Electronic address:
Modelling the diffusion-relaxation magnetic resonance (MR) signal obtained from multi-parametric sequences has recently gained immense interest in the community due to new techniques significantly reducing data acquisition time. A preferred approach for examining the diffusion-relaxation MR data is to follow the continuum modelling principle that employs kernels to represent the tissue features, such as the relaxations or diffusion properties. However, constructing reasonable dictionaries with predefined signal components depends on the sampling density of model parameter space, thus leading to a geometrical increase in the number of atoms per extra tissue parameter considered in the model.
View Article and Find Full Text PDFJ Environ Radioact
September 2025
Analytical Chemistry and Control Department, Hot Laboratories and Waste Management Center (HLWMC), Egyptian Atomic Energy Authority (EAEA), 13759, Cairo, Egypt.
The huge volume waste of the produced water (PW) associated with petroleum extraction poses significant hazards to the surrounded environment due to its complex composition and the presence of various hazardous pollutants, including organic, inorganic, biological contaminants, and natural occurring radioactive materials (NORM). This study was conducted to investigate the factors affecting the removal of the long-lived radium isotopes, i.e.
View Article and Find Full Text PDFEntropy (Basel)
August 2025
Department of Physics, College of Science, Imam Mohammad Ibn Saud Islamic University (IMSIU), P.O. Box 90950, Riyadh 11623, Saudi Arabia.
In this work, we investigate the quantum coherence and purity in hydrogen atoms under dissipative dynamics, with a focus on the hyperfine structure states arising from the electron-proton spin interaction. Using the Lindblad master equation, we model the time evolution of the density matrix of the system, incorporating both the unitary dynamics driven by the hyperfine Hamiltonian and the dissipative effects due to environmental interactions. Quantum coherence is quantified using the L1 norm and relative entropy measures, while purity is assessed via von Neumann entropy, for initial states, including a maximally entangled Bell state and a separable state.
View Article and Find Full Text PDFPhys Chem Chem Phys
July 2025
Institute of Chemical Physics, Vilnius University, Saulėtekio av. 3, Vilnius, LT-10257, Lithuania.
Atomic orbital (AO) normalization is a foundational assumption in electronic structure theory, yet in practice, the norm of contracted basis functions can deviate from unity due to internal reduction and transformation mechanisms applied by quantum chemistry packages. This work presents a systematic framework for analyzing the physical and numerical consequences of primitive basis function elimination and AO-level norm inconsistency. The implemented methodology quantifies norm loss, separates constructive and destructive contributions, and enables precise renormalization by retaining both positive and negative terms within AO representations.
View Article and Find Full Text PDFOpt Express
September 2024
The geometric phase that introduces the phase discontinuities by the twist of individual meta-atoms has attracted intensive interest in designing multifunctional planar metasurfaces. Typically, the twist axis aligns parallel to the plane of incidence, defined as the plane formed by the norm to the boundary surface and the incident wave vector, termed here as the longitudinal axis. So far, the degree of freedom associated with the other two transverse axes perpendicular to the plane of incidence remains rarely explored.
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