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MICROcomputer REALIZATIONS OF LYNN FAST DIGITAL-FILTERING DESIGNS

MEDICAL & BIOLOGICAL engineering & COMPUTING 1980年第5期18卷 638-642页

作者： MALIK, NR Electrical & Computer Engineering Program University of Iowa Iowa City USA

The feasibility of real-time digital filtering using dedicated state-of-the-art microcomputers of 8-bit wordlength is demonstrated. Implementations of Lynn's integer filter structures by means of wrap-around queue data structures are shown to operate at sampling rates of over 8 kHz. An initial condition constraint unique to this filter class which must be satisfied to prevent inadvertent overflows or oscillations in microcomputers is discussed. The fast-filtering techniques are applied to the problem of calculating the average absolute value of a fast signal in real time.

关键词： Digital filters Microcomputers Online computing Signal processing

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Three-dimensional computation of light scattering from cells

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IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1996年第4期2卷 898-905页

作者： Dunn, A RichardsKortum, R Biomedical Engineering Program Department of Electrical and Computer Engineering University of Technology Austin TX USA

Using the finite-difference time-domain method, three-dimensional scattering patterns are computed for cells containing multiple organelles. The scattering cross section and average cosine of the scattering angle are computed for cells as a function of volume fraction of melanin granules and mitochondria, Results show that small organelles play a significant role in light scattering from cells, and the volume fraction of organelles affects both the total amount of scattered light and the angular distribution of scattered light.

关键词： Light scattering Optical scattering Mie scattering Electromagnetic scattering Cells (biology) Optical refraction Finite difference methods Time domain analysis Biomedical optical imaging High-resolution imaging

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Symbolic regression approach for analytical modeling of ITU-R P.1546-6 propagation curves

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Telecommunication Systems 2025年第2期88卷 1-28页

作者： Oliveira, Guilherme Kneitz de Haddad, Diego Barreto Giraldi, Gilson Antonio Dias, Maurício Henrique Costa Computer Engineering Coord. CEFET-RJ Rua do Imperador 971 Centro Histórico Rio de Janeiro Petrópolis 25620003 Brazil Master’s Program in Electrical Engineering (PPEEL) CEFET-RJ Av. Maracanã 229 Rio de Janeiro Rio de Janeiro 20271110 Brazil COMAC LNCC Av. Getúlio Vargas 333 Rio de Janeiro Petrópolis 25651-075 Brazil

Accurately modeling wireless channel propagation is essential for the design and optimization of wireless systems. Large-scale propagation models predict path loss and received signal strength, with Recommendation ITU-R P.1546-6 being a key resource for scenarios involving extended distances and antenna heights, operating over 30 MHz to 4000 MHz and antenna heights from 10 m to 1200 m. This paper employs symbolic regression, a machine learning approach combining genetic programming with experimental data, to derive analytical expressions for the field-strength curves in this Recommendation. Unlike neural networks, which function as black-box models, symbolic regression yields explicit mathematical expressions that enable direct interpolation for unlisted configurations and provide analytical insights into the propagation behavior. Nevertheless, the derived formulas offer an alternative to tabulated data, bridging the gap between purely empirical approaches and black-box models such as neural networks. The findings contribute to the understanding of propagation challenges and highlight the trade-offs in analytical modeling for complex scenarios. Analytical formulas with minimal complexity were sought, under the constraint that the maximum absolute error in dB, compared to measured data, should be less than 2 dB for distances ranging from 1 km to 1000 km between the antenna and the receiver. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.

关键词： Communication Systems Design Propagation Loss Modeling Symbolic Regression

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Unbiased Parameter Estimation for Bayesian Inverse Problems

arXiv

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arXiv 2025年

作者： Chada, Neil K. Jasra, Ajay Maama, Mohamed Tempone, Raul Department of Mathematics City University of Hong Kong China School of Data Science The Chinese University of Hong Kong Shenzhen CN Shenzhen China Applied Mathematics and Computational Science Program Computer Electrical and Mathematical Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

In this paper we consider the estimation of unknown parameters in Bayesian inverse problems. In most cases of practical interest, there are several barriers to performing such estimation, This includes a numerical approximation of a solution of a differential equation and, even if exact solutions are available, an analytical intractability of the marginal likelihood and its associated gradient, which is used for parameter estimation. The focus of this article is to deliver unbiased estimates of the unknown parameters, that is, stochastic estimators that, in expectation, are equal to the maximizer of the marginal likelihood, and possess no numerical approximation error. Based upon the ideas of [4] we develop a new approach for unbiased parameter estimation for Bayesian inverse problems. We prove unbiasedness and establish numerically that the associated estimation procedure is faster than the current state-of-the-art methodology for this problem. We demonstrate the performance of our methodology on a range of problems which include a PDE and ODE. Copyright © 2025, The Authors. All rights reserved.

关键词： Markov processes

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Corrections to “Comprehensive Analysis of Design and Performance Evaluation Methodologies for a High-Resolution Read-Out IC With Ultralow 1/ f Corner for DC Measurement Applications”

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IEEE Transactions on Instrumentation and Measurement 2025年 74卷

作者： Junho Kang Woosol Han Suhwan Kim Jaehoon Jun Department of Electrical and Computer Engineering and the Inter-University Semiconductor Research Center (ISRC) Seoul National University Seoul South Korea Department of Electrical and Computer Engineering and Program in Semiconductor Convergence Inha University Incheon South Korea Department of Electrical and Computer Engineering Seoul National University Seoul South Korea Gwanak Analog Company Ltd. Seoul South Korea Department of Electrical and Computer Engineering and the Program in Semiconductor Convergence Inha University Incheon South Korea

Presents corrections to the paper, (Corrections to “Comprehensive Analysis of Design and Performance Evaluation Methodologies for a High-Resolution Read-Out IC With Ultralow 1/ f Corner for DC Measurement Application... 详细信息

关键词： Performance evaluation

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DESCRIPTION AND PERFORMANCE OF A FIBEROPTIC CONFOCAL FLUORESCENCE SPECTROMETER

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APPLIED SPECTROSCOPY 1994年第3期48卷 350-355页

作者： RICHARDSKORTUM, R DURKIN, A ZENG, J Biomedical Engineering Program Department of Electrical and Computer Engineering University of Texas at Austin Austin Texas 78712

We describe a fiber-optic-based confocal fluorescence spectrometer for obtaining depth-resolved, attenuated fluorescence emission spectra with lateral resolution of several microns and depth resolution of tens of microns. The confocal optics of the spectrometer are small, inexpensive, and easy to construct and to interface to existing spectrometers. We compare the performance of this system to that of conventional fluorescence spectrometers for nonscattering homogeneous and inhomogeneous samples. We demonstrate that the confocal measurements readily provide information about the sample geometry and optical properties not available from nonconfocal measurements. Potential applications of the technique are discussed.

关键词： FLUORESCENCE SPECTROSCOPY CONFOCAL FIBER OPTIC

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ACOUSTIC TRANSMISSION OF THE RESPIRATORY SYSTEM USING SPEECH STIMULATION

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IEEE TRANSACTIONS ON BIOMEDICAL engineering 1991年第2期38卷 126-132页

作者： COHEN, A BERSTEIN, AD Department of Electrical and Computer Engineering Biomedical Engineering Program Ben-Gurion University of the Negev Beersheba Israel

Two methods for the analysis of the acoustic transmission of the respiratory system are presented. Continuous speech utterance is used as acoustic stimulation. The transmitted acoustic signal is recorded from various sites over the chest wall. The AR method analyzes the power spectral density function of the transmitted sound, which heavily depends on the microphone assembly and the utterance. The method was applied to a screening problem and was tested on a small database that consisted of 19 normal and five abnormal patients. Using the first five AR coefficients and the prediction error of an AR(10) model, as discriminating features, the system screened all abnormals. An ARMA method is suggested, which eliminates the dependence on microphone and utterance. In this method, the generalized least squares identification algorithm is used to estimate the ARMA transfer function of the respiratory system. The normal transfer function demonstrates a peak at the range of 130-250 Hz and sharp decrease in gain for higher frequencies. A pulmonary fibrotic patient demonstrated a peak at the same frequency range, a much higher gain in the high frequency range with an additional peak at about 700 Hz.

关键词： Respiratory system Speech Microphones Transfer functions Frequency Spectral analysis Density functional theory Assembly Acoustic testing Spatial databases

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Unavoidable multilevel biaxial symmetry breaking in chiral hybrid liquid crystals

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Physical Review E 2025年第4期111卷 045410-045410页

作者： Jin-Sheng Wu Marina Torres Lázaro Souvik Ghosh Haridas Mundoor Henricus H. Wensink Ivan I. Smalyukh Department of Physics and Chemical Physics Program University of Colorado Boulder Colorado 80309 USA Laboratoire de Physique des Solides–UMR 8502 Université Paris-Saclay and CNRS 91405 Orsay France International Institute for Sustainability with Knotted Chiral Meta Matter Hiroshima University Higashihiroshima Japan Department of Electrical Computer and Energy Engineering Materials Science and Engineering Program and Soft Materials Research Center University of Colorado Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado Boulder Colorado 80309 USA

Chiral nematic or cholesteric liquid crystals (LCs) are fluid mesophases with long-ranged orientational order featuring a quasilayered periodicity imparted by a helical director configuration but lacking long-range positional order. Doping molecular cholesteric LCs with strongly anisotropic uniaxial colloidal particles adds another level of complexity because of the interplay between weak surface-anchoring boundary conditions and bulk-based elastic distortions near the particle-LC interface. Using cylindrical colloidal disks and rods with different geometric shapes and surface conditions, we demonstrate that these colloidal inclusions generically exhibit biaxial orientational probability distributions which may impart anomalously strong local biaxiality onto the hybrid cholesteric LC structure. Unlike nonchiral hybrid molecular-colloidal LCs, where biaxial order emerges only at critical colloid volume fractions exceeding some uniaxial-biaxial transition value, the orientational probability of the colloidal inclusions immersed in chiral nematic hosts is unambiguously biaxial even at infinite dilution. We demonstrate that the colloids induce local biaxial perturbations within the molecular orientational order of the LC host medium which strongly enhances the weak but native biaxial order of chiral nematic LC induced by the chiral symmetry breaking of the director field. With the help of analytical modeling and computer simulations based on the Landau–de Gennes free energy of the host LC around the colloids, we rationalize the observed multilevel biaxial order and conclude that it is not only unavoidable but also strongly enhanced compared to both achiral hybrid LCs and purely molecular cholesteric LCs.

关键词： Cholesteric liquid crystals

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The Role of Harmonization: A Systematic Analysis of Various Task-based Scenarios

The Role of Harmonization: A Systematic Analysis of Various ...

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Medical Imaging 2025: Physics of Medical Imaging

作者： Xia, Shao-Jun Vancoillie, Liesbeth Sotoudeh-Paima, Saman Zarei, Mojtaba Ho, Fong Chi Tushar, Fakrul Islam Chen, Xiaoyang Dahal, Lavsen Lafata, Kyle J. Abadi, Ehsan Lo, Joseph Y. Samei, Ehsan Center for Virtual Imaging Trials Carl E. Ravin Advanced Imaging Labs Department of Radiology Durham United States Department of Biomedical Engineering Durham United States Department of Electrical & Computer Engineering Durham United States Medical Physics Graduate Program Durham United States Department of Physics Durham United States Department of Radiation Oncology Duke University Durham United States

ISBN: (纸本)9781510685888

In medical imaging, harmonization plays a crucial role in reducing variability arising from diverse imaging devices and protocols. Patient images obtained under different computed tomography (CT) scan conditions may show varying performance when analyzed using an artificial intelligence model or quantitative assessment. This necessitates the need for harmonization. Virtual imaging trial (VIT) through digital simulation can be used to develop and assess the effectiveness of harmonization models to minimize data variability. The purpose of this study was to assess the utility of a VIT platform for harmonization across a range of lung imaging scenarios. To ensure consistent and reliable analysis across different virtual imaging datasets, we conducted a multi-objective assessment encompassing three typical task-based scenarios: lung structure segmentation, chronic obstructive pulmonary disease (COPD) quantification, and lung nodule quantification. A physics-informed deep neural network was applied as the unified harmonization model for all three tasks. Evaluation results before and after harmonization reveal three findings: 1) modestly improved Dice scores and reduced Hausdorff Distances at 95th Percentile in lung structure segmentation;2) decreased variation in biomarkers and radiomics features in COPD quantification;and 3) increased number of radiomics features with high intraclass correlation coefficient in lung nodule quantification. The results demonstrate the significant potential of harmonization across various task-based scenarios and provide a benchmark for the design of efficient harmonizers. © 2025 SPIE.

关键词： Lung cancer

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Probabilistic genotype-phenotype maps reveal mutational robustness of RNA folding, spin glasses, and quantum circuits

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Physical Review Research 2025年第1期7卷 013118-013118页

作者： Anna Sappington Vaibhav Mohanty Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Harvard-MIT Program in Health Sciences and Technology Harvard Medical School Boston Massachusetts 02115 USA and Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Harvard/MIT MD-PhD Program Harvard Medical School Boston Massachusetts 02115 USA and Massachusetts Institute of Technology Cambridge Massachusetts 02139 USA Department of Chemistry and Chemical Biology Harvard University Cambridge Massachusetts 02138 USA

Recent studies of genotype-phenotype maps have reported universally enhanced phenotypic robustness to genotype mutations, a feature essential to evolution. Virtually all of these studies make a simplifying assumption that each genotype—represented as a sequence—maps deterministically to a single phenotype, such as a discrete structure. Here we introduce probabilistic genotype-phenotype (PrGP) maps, where each genotype maps to a vector of phenotype probabilities, as a more realistic and universal language for investigating robustness in a variety of physical, biological, and computational systems. We study three model systems to show that PrGP maps offer a generalized framework which can handle uncertainty emerging from various physical sources: (1) thermal fluctuation in RNA folding, (2) external field disorder in the spin-glass ground state search problem, and (3) superposition and entanglement in quantum circuits, which are realized experimentally on IBM quantum computers. In all three cases, we observe a biphasic robustness scaling which is enhanced relative to random expectation for more frequent phenotypes and approaches random expectation for less frequent phenotypes. We derive an analytical theory for the behavior of PrGP robustness, and we demonstrate that the theory is highly predictive of empirical robustness.

关键词： Quantum computers

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