Power inversion (PI) is a known adaptive beamforming algorithm that is widely used in wireless communication systems for anti-jamming purposes. The PI algorithm is typically implemented in a digital domain, which requires the radio-frequency signals to be down-converted into base-band signals, and then sampled by ADCs. In practice, the down-conversion circuit will introduce phase noises into the base-band signals, which may degrade the performance of the algorithm. At present, the impacts of phase noise on the PI algorithm have not been studied, according to the open literature, which is, however, important for practical design. Therefore, in this paper, we present a theoretical analysis on the impacts, provide a new mathematical model of the PI algorithm, and offer a closed-form formula of the interference cancellation ratio (ICR) to quantify the relations between the algorithm performance and the phase noise level, as well as the number of auxiliary antennas. We find that the ICR in decibel decreases logarithmically linearly with the phase noise variance. In addition, the ICR improves with an increasing number of auxiliary antennas, but the increment is upper-bounded. The above findings are verified with both simulated and measured phase noise data.
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http://dx.doi.org/10.3390/s22062362 | DOI Listing |
Invest Radiol
January 2025
From the Department of Radiology, Ulsan University Hospital, Ulsan, Republic of Korea (T.Y.L.); Department of Radiology, University of Ulsan College of Medicine, Seoul, Republic of Korea (T.Y.L.); Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea (J.H.Y., H.K., J.M.L.); Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea (J.H.Y., S.H.P., J.M.L.); Department of Radiology, Inje University Busan Paik Hospital, Busan, Republic of Korea (J.Y.P.); Department of Radiology, Seoul National University Bundang Hospital, Seongnam, Republic of Korea (S.H.P.); Department of Radiology, Hanyang University College of Medicine, Seoul, Republic of Korea (C.L.); Division of Biostatistics, Medical Research Collaborating Center, Seoul National University Hospital, Seoul, Republic of Korea (Y.C.); and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Republic of Korea (J.M.L.).
Objective: The aim of this study was to intraindividually compare the conspicuity of focal liver lesions (FLLs) between low- and ultra-low-dose computed tomography (CT) with deep learning reconstruction (DLR) and standard-dose CT with model-based iterative reconstruction (MBIR) from a single CT using dual-split scan in patients with suspected liver metastasis via a noninferiority design.
Materials And Methods: This prospective study enrolled participants who met the eligibility criteria at 2 tertiary hospitals in South Korea from June 2022 to January 2023. The criteria included (a) being aged between 20 and 85 years and (b) having suspected or known liver metastases.
J Opt Soc Am A Opt Image Sci Vis
August 2024
Frequency-domain near-infrared spectroscopy (FD-NIRS) is a noninvasive method for quantitatively measuring optical absorption and scattering in tissue. This study introduces structured interrogation (SI) as an interference-based approach for implementing FD-NIRS in order to enhance optical property estimation in multilayered tissues and sensitivity to deeper layers. We find that, in the presence of realistic noise, SI accurately estimates properties and chromophore concentrations with less than a 5% error.
View Article and Find Full Text PDFJ Res Med Sci
December 2024
Department of Medical Imaging Center, Affiliated Hospital of Shandong Second Medical University, Weifang, Shandong, China.
Background: Accurate and timely assessment of tumor response after chemotherapy is crucial in clinical settings. The aim of this study was to explore the feasibility of Gemstone Spectral Imaging (GSI) for early assessment of chemotherapy responses in patients with colorectal cancer liver metastasis (CRCLM).
Materials And Methods: From October 2012 to October 2018, 46 patients (28 males and 18 females) with CRCLM received GSI followed by chemotherapy were retrospectively reviewed.
J Neural Eng
January 2025
School of Biomedical Engineering, Southern Medical University, 1023 Shatai Road, Baiyun District, Guangzhou, Guangdong, 510515, CHINA.
Objective: Entrainment has been considered as a potential mechanism underlying the facilitatory effect of rhythmic neural stimulation on neurorehabilitation. The inconsistent effects of brain stimulation on neurorehabilitation found in the literature may be caused by the variability in neural entrainment. To dissect the underlying mechanisms and optimize brain stimulation for improved effectiveness, it is critical to reliably assess the occurrence and the strength of neural entrainment.
View Article and Find Full Text PDFiScience
January 2025
Department of Electrical and Computering Engineering, Binghamton University, Binghamton, NY 13902, USA.
Our recent research on type-I quadrature parity-time (PT) symmetry, utilizing an open twin-beam system, not only enables observing genuine quantum photonic PT symmetry amid phase-sensitive amplification (PSA) and loss in the presence of Langevin noise but also reveals an additional classical-to-quantum (C2Q) transition in noise fluctuations. In contrast to the previous setup, our exploration of an alternative system assuming no loss involves a type-II PSA-only scheme. This scheme facilitates dual opposing quadrature-PT symmetry, offering a comprehensive and complementary comprehension of C2Q transitions and PT-enhanced quantum sensing with optimal performance in the symmetry unbroken region.
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