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arXiv 2025年

作者： Owens, Jonathan R. Farag, Marwa H. Rao, Pooja Giani, Annarita GE Vernova Advanced Research Center NiskayunaNY12302 United States Quantum Algorithm Engineering NVIDIA Santa ClaraCA95051 United States

We perform a series of calculations using simulated QPUs, accelerated by NVIDIA CUDA-Q platform, focusing on a molecular analog of an amine-functionalized metal-organic framework (MOF) — a promising class of materials for CO2 capture. The variational quantum eigensolver (VQE) technique is employed, utilizing the unitary coupled-cluster method with singles and doubles (UCCSD) within active spaces extracted from the larger material system. We explore active spaces of (6e,6o), (10e,10o), and (12e,12o), corresponding to 12, 20, and 24 qubits, respectively, and simulate them using CUDA-Q’s GPU-accelerated state-vector simulator. Notably, the 24-qubit simulations—among the largest of their kind to date—are enabled by gate fusion optimizations available in CUDA-Q. While these active space sizes are among the largest reported in the context of CO2 chemisorption, they remain insufficient for a fully accurate study of the system. This limitation arises from necessary simplifications and scalability challenges of VQE, particularly the barren plateau problem. Nonetheless, this work demonstrates the application of VQE to a novel material system using large-scale simulated QPUs and offers a blueprint for future quantum chemistry calculations. © 2025, CC BY.

关键词： Molecular orbitals

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High-resolution simulations of nonlinear electromagnetic turbulence in tokamak devices

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The European Physical Journal Special Topics 2025年 1-14页

作者： Liu, Yanjun Liu, Zixi Liu, Jian Gao, Baofeng Zhang, Wei Xia, Tianyang Liu, Haiqing Zhuang, Ge Gao, Xiang Institute of Plasma Physics Chinese Academy of Sciences Anhui China KTX Laboratory and Department of Engineering and Applied Physics University of Science and Technology of China Anhui China Weihai Institute for Interdisciplinary Research Shandong University Shandong China SDU-ANU Joint Science College Shandong University Shandong China Shandong Computer Science Center (National Supercomputing Center in Jinan) Qilu University of Technology (Shandong Academy of Sciences) Shandong China Advanced Algorithm Joint Lab National Supercomputing Center in Jinan Shandong China

To achieve long-pulse steady operation, the physical mechanisms of boundary turbulence need further investigation. We employ the two-fluid model with flute reduction on BOUT++ to simulate the boundary plasma in Tokamaks. The space and time scales of turbulence reproduced by our simulations closely relate to the spatial mesh size and time step size, respectively. As an inherent time scale, the Alfven time is sufficient to resolve MHD instabilities. The spatial scale can be refined by increasing mesh resolutions, which necessitates larger scale parallel computing resources. We have conducted nonlinear simulations using more than 33 million spatial meshes with 16,384 CPU processors in parallel. The results indicate that while the decrease in parallel efficiency with an increase in core numbers does not necessarily lead to shorter runtimes, higher computational complexity improves parallel efficiency for the same number of cores. In addition, the mesh resolution required for convergence conditions differs between linear and nonlinear simulations, with nonlinear simulations demanding higher resolution. Besides finer structure obtained, the fluctuation characteristic of density similar to WCM, which is more consistent with the experimental observation, also shows the requirement for high-resolution meshes and large-scale computing in the future.

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Performance of a continuous real-time QT interval monitoring algorithm for the critical-care setting

Performance of a continuous real-time QT interval monitoring...

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2006 Computers in Cardiology, CIC

作者： Helfenbein, Eric Zhou, S.H. Feild, D.Q. Lindauer, J.M. Gregg, R.E. Wang, J.Y. Kresge, S.S. Michaud, F.P. Advanced Algorithm Research Center Philips Medical Systems Milpitas CA United States Philips Medical Systems Advanced Algorithm Research Center Building 3 South 540 Alder Drive Milpitas CA 95035 United States

ISBN: (纸本)1424425328

We developed an automated continuous real-time QTc interval monitoring algorithm for the critical-care setting. The performance of the QT interval measurement algorithm was tested on the PhysioNet adult QT ECG dataset (n=105), and on a pediatric ECG dataset (n=20) and a neonatal dataset (n = 24) recorded from intensive care units. The algorithm performance is measured by sensitivity (the ability to measure the QT interval), and accuracy (the difference between the automated QT measurements and cardiologists' manual annotations). We obtained 92% sensitivity in the adult group, 85% in the pediatric group and 75% in the neonatal group. On the 95 adult cases which had both an algorithm and a cardiologist measurement, the mean difference was 1 ms with a standard deviation of 35 ms. On the pediatric ECGs, the mean difference was -12 ms with a standard deviation of 20 ms. In the neonatal cases, the mean difference was -6 ms with a standard deviation of 12 ms.

关键词： Pediatrics

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Modeling and Classification of the ST Segment Morphology for Enhanced Detection of Acute Myocardial Infarction

Modeling and Classification of the ST Segment Morphology for...

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2019 Computing in Cardiology, CinC 2019

作者： Firoozabadi, Reza Gregg, Richard E. Babaeizadeh, Saeed Philips Healthcare Advanced Algorithm Research Center 3000 Minuteman Rd AndoverMA01810 United States

ISBN: (纸本)9781728169361

A number of cardiac conditions such as acute pericarditis (PC) and early repolarization (ER) cause ST elevation which mimics ST-segment Elevation Myocardial Infarction (STEMI). Current guidelines recommend analyzing ST segment morphology to distinguish STEMI from these confounders. ST elevation in PC and ER (and possibly in STEMI) is concave (upward) in the JTpeak interval, while a convex or straight ECG ST segment is associated with the diagnosis of STEMI. We developed an algorithm to classify concavity characteristic of the ST segment. A quadratic polynomial regression algorithm was introduced to model the shape of JTpeak interval. Our diagnostic algorithm generated representative beats and measured the fiducial points and standard measurements such as ST level in 12-lead 10-sec segments of ECG recordings. JTpeak interval was modeled by a parabola using a least-squares polynomial regression algorithm. Classifier features such as curvature, parabola direction and vertex, model fit error, and the noise measure were determined. A bootstrap-aggregated tree ensemble classifier determined the ST segment shape. Our algorithm was evaluated on a 12-lead ECG database collected in two medical centers. Our ST segment polynomial regression model exhibited significant improvement in concavity detection versus a simple conventional method. © 2019 Creative Commons.

关键词： Morphology

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An Ensemble of Bagged Decision Trees for Early Prediction of Sepsis

An Ensemble of Bagged Decision Trees for Early Prediction of...

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2019 Computing in Cardiology, CinC 2019

作者： Firoozabadi, Reza Babaeizadeh, Saeed Philips Healthcare Advanced Algorithm Research Center 3000 Minuteman Rd AndoverMA01810 United States

ISBN: (纸本)9781728169361

Sepsis is a serious medical condition caused by the body's response to an infection. Early prediction and treatment of sepsis are critical. In response to the PhysioNet/CinC Challenge 2019, we developed an algorithm for early prediction of sepsis. Three datasets provided by the challenge are from ICU patients in three separate hospitals, two of which are publicly available to the participants, but the third is hidden and used for scoring. Data are highly unbalanced and contain many missing values. Each patient's data comprises hourly collected samples of 40 features. We preprocessed the data by a plausibility filter eliminating the outliers, forward filling of the missing data and replacing the remaining by population mean, and standardization of the numerical data. We developed an ensemble of bagged decision trees with a highly unbalanced misclassification cost to predict the sepsis for each sample of features in a patient. The classifier was trained on the first hospital dataset and validated on the second hospital dataset. A total of 15 important features and a set of hyperparameters were selected in an iterative training approach. Our team (AlgTeam, ranking 39) submitted nine entries for evaluation on the subset of the hidden data and selected the entry with highest utility score which resulted in the final utility score of 0.24 on the full test dataset. © 2019 Creative Commons.

关键词： Decision trees

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A Graphical Evaluation Tool to Utilize ECG Data Without Reference Annotation

A Graphical Evaluation Tool to Utilize ECG Data Without Refe...

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2019 Computing in Cardiology, CinC 2019

作者： Zhang, Yu-He Babaeizadeh, Saeed Philips Healthcare Advanced Algorithm Research Center 3000 Minuteman Road AndoverMA01810 United States

ISBN: (纸本)9781728169361

Without reference annotation, statistical metrics such as sensitivity and positive predictive value (PPV) cannot be calculated. Annotating a large ECG database may not be feasible, hence, the interest in developing an evaluation tool that does not require reference annotation. We developed a tool for evaluating key performance attributes (KPA) including arrhythmia detection, heart rate, ST value, and noise tolerance. The tool has three layers of KPA graphics. The top layer includes interactive distribution graphs of the KPA values for aggregated results for the entire database. From this top layer the user can select an individual record to launch interactive trending graphs that display the KPA values, or their discrepancies, for a time span on that particular record. From this second layer the user can identify any KPA value of interest (e.g., a specific arrhythmia label) to view the underlying ECG waveform. Navigating through these three layers, the user is able to quickly confirm the validity of KPA reported by the algorithm. We modified the noise tolerance of an exercise ECG arrhythmia algorithm. Then used this tool to visually verify the resulting improvement on the Telemetric and Holter ECG Warehouse (THEW) stress database E-OTH-12-0927-015. We confirmed the visual verification of improvement by manually annotating a small subset of records in this database. © 2019 Creative Commons.

关键词： Database systems

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A model for estimation of noise tolerance in ECG parameters

A model for estimation of noise tolerance in ECG parameters

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Computers in Cardiology (CinC)

作者： Reza Firoozabadi Richard E. Gregg Saeed Babaeizadeh Philips Healthcare Advanced Algorithm Research Center (AARC) Philips Healthcare Advanced Algorithm Research Center Andover MA USA

ISBN: (纸本)9781509008964

Parameters extracted from ECG recordings show different noise tolerance levels. Some parameters may be slightly affected by noise, while the others could be inaccurate. Choosing a single noise threshold for all parameters may lead to adoption of invalid results or removal of valid parameters. In this study, we develop a statistical model between the Signal-to-Noise Ratio (SNR) and our Signal Quality Indicator (SQI) algorithm, and determine the noise-tolerance threshold for several ECG parameters statistically. Our dataset was based on the STAFF-III database with added physical noise recording segments from MIT-BIH database containing electrode motion, muscle artifact and baseline wander. We generated 3193 noise-added 12-lead ECG signals with SNR varying from -6dB to 24dB. For each 10-second segment, the noise level was measured by our SQI algorithm, and ECG parameters were measured by the Philips DXL ECG algorithm, allowing us to derive a noise model and the thresholds for noise tolerance of the ECG parameters. Varying thresholds suggest using parameter-specific thresholds in order to avoid reduction in accuracy.

关键词： Electrocardiography Noise measurement Signal to noise ratio Noise level Databases Current measurement Frequency measurement

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Comparison of methods for allocating costs of empty railcar movements in a railcar pooling system

Comparison of methods for allocating costs of empty railcar ...

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作者： Cheng, Yao Lin, Wei-Hua Advanced Traffic and Logistics Algorithm Systems Research Center Department of Systems and Industrial Engineering University of Arizona Tucson AZ 85721 United States

Allocating the cost of empty railcar miles to partners in a railcar pooling system is an important pricing problem in railway management. Recently, the authors of this paper proposed a cost allocation scheme for empty railcar movements based on game theory that explicitly considers the level of participation and contribution from each partner, the costs generated before and after cooperation, and the overall benefit obtained by each partner because of cooperation. This paper compares the performance of the model with three other cost allocation models with respect to fairness, stability, and computational efficiency. The comparison is made with two scenarios adapted from examples documented in the literature. The results indicate that the cost allocation scheme based on game theory outperforms other methods in ensuring fairness and enhancing stability in a coalition. Most remarkably, it yields reasonable results even in situations in which other models behave poorly. Computationally, it is manageable for practical problems.

关键词： Railroad cars

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Lead-wire interchange detection in practical settings

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Journal of Electrocardiology 2024年 84卷 37-38页

作者： Zhang, Yu-He, PhD Gregg, Richard, MS Advanced Algorithm Research Center Philips Healthcare Andover MA USA

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Effects of data augmentation and filters for automatic diagnosis of 12-lead ECG using residual network based deep learning

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Journal of Electrocardiology 2022年 73卷 16-17页

作者： An, Junmo Gregg, Richard E. Babaeizadeh, Saeed Advanced Algorithm Research Center Philips Healthcare Cambridge MA USA

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