检索结果-内蒙古大学图书馆

Bridging preference-based instrumental variable studies and cluster-randomized encouragement experiments: Study design, noncompliance, and average cluster effect ratio

arXiv

引用

arXiv 2020年

作者： Zhang, Bo Heng, Siyu Mackay, Emily J. Ye, Ting Department of Statistics The Wharton School University of Pennsylvania PhiladelphiaPA United States Graduate Group in Applied Mathematics and Computational Science School of Arts and Sciences University of Pennsylvania PhiladelphiaPA United States Department of Anesthesiology and Critical Care Perelman School of Medicine University of Pennsylvania PhiladelphiaPA United States

Instrumental variable methods are widely used in medical and social science research to draw causal conclusions when the treatment and outcome are confounded by unmeasured confounding variables. One important feature of such studies is that the instrumental variable is often applied at the cluster level, e.g., hospitals’ or physicians’ preference for a certain treatment where each hospital or physician naturally defines a cluster. This paper proposes to embed such observational instrumental variable data into a cluster-randomized encouragement experiment using statistical matching. Potential outcomes and causal assumptions underpinning the design are formalized and examined. Testing procedures for two commonly-used estimands, Fisher’s sharp null hypothesis and the pooled effect ratio, are extended to the current setting. We then introduce a novel cluster-heterogeneous proportional treatment effect model and the relevant estimand: the average cluster effect ratio. This new estimand is advantageous over the structural parameter in a constant proportional treatment effect model in that it allows treatment heterogeneity, and is advantageous over the pooled effect ratio estimand in that it is immune to Simpson’s paradox. We develop an asymptotically valid randomization-based testing procedure for this new estimand based on solving a mixed integer quadratically-constrained optimization problem. The proposed design and inferential methods are applied to a study of the effect of using transesophageal echocardiography during CABG surgery on patients’ 30-day mortality rate. Copyright © 2020, The Authors. All rights reserved.

关键词： Hospitals

来源：评论

学校读者我要写书评

暂无评论

Benchmarking quantum logic operations relative to thresholds for fault tolerance

arXiv

引用

arXiv 2022年

作者： Hashim, Akel Seritan, Stefan Proctor, Timothy Rudinger, Kenneth Goss, Noah Naik, Ravi K. Kreikebaum, John Mark Santiago, David I. Siddiqi, Irfan Quantum Nanoelectronics Laboratory Department of Physics University of California at Berkeley BerkeleyCA94720 United States Graduate Group in Applied Science and Technology University of California at Berkeley BerkeleyCA94720 United States Computational Research Division Lawrence Berkeley National Lab BerkeleyCA94720 United States Quantum Performance Laboratory Sandia National Laboratories AlbuquerqueNM87185 United States Quantum Performance Laboratory Sandia National Laboratories LivermoreCA94550 United States Materials Sciences Division Lawrence Berkeley National Lab BerkeleyCA94720 United States Materials Sciences Division Lawrence Berkeley National Lab BerkeleyCA94720 United States

Contemporary methods for benchmarking noisy quantum processors typically measure average error rates or process infidelities. However, thresholds for fault-tolerant quantum error correction are given in terms of worst-case error rates - defined via the diamond norm - which can differ from average error rates by orders of magnitude. One method for resolving this discrepancy is to randomize the physical implementation of quantum gates, using techniques like randomized compiling (RC). In this work, we use gate set tomography to perform precision characterization of a set of two-qubit logic gates to study RC on a superconducting quantum processor. We find that, under RC, gate errors are accurately described by a stochastic Pauli noise model without coherent errors, and that spatially-correlated coherent errors and non-Markovian errors are strongly suppressed. We further show that the average and worst-case error rates are equal for randomly compiled gates, and measure a maximum worst-case error of 0.0197(3) for our gate set. Our results show that randomized benchmarks are a viable route to both verifying that a quantum processor's error rates are below a fault-tolerance threshold, and to bounding the failure rates of near-term algorithms, if - and only if - gates are implemented via randomization methods which tailor noise. Copyright © 2022, The Authors. All rights reserved.

关键词： Benchmarking

来源：评论

学校读者我要写书评

暂无评论

Randomized Compiling for Scalable Quantum Computing on a Noisy Superconducting Quantum Processor

引用

Physical Review X 2021年第4期11卷 041039-041039页

作者： Akel Hashim Ravi K. Naik Alexis Morvan Jean-Loup Ville Bradley Mitchell John Mark Kreikebaum Marc Davis Ethan Smith Costin Iancu Kevin P. O’Brien Ian Hincks Joel J. Wallman Joseph Emerson Irfan Siddiqi Quantum Nanoelectronics Laboratory Department of Physics University of California at Berkeley Berkeley California 94720 USA Graduate Group in Applied Science and Technology University of California at Berkeley Berkeley California 94720 USA Computational Research Division Lawrence Berkeley National Lab Berkeley California 94720 USA Materials Sciences Division Lawrence Berkeley National Lab Berkeley California 94720 USA Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology Cambridge Massachusetts 02142 USA Quantum Benchmark Inc. Kitchener Ontario N2H 5G5 Canada Keysight Technologies Canada Kanata Ontario K2K 2W5 Canada Institute for Quantum Computing and Department of Applied Mathematics University of Waterloo Waterloo Ontario N2L 3G1 Canada

The successful implementation of algorithms on quantum processors relies on the accurate control of quantum bits (qubits) to perform logic gate operations. In this era of noisy intermediate-scale quantum (NISQ) computing, systematic miscalibrations, drift, and crosstalk in the control of qubits can lead to a coherent form of error that has no classical analog. Coherent errors severely limit the performance of quantum algorithms in an unpredictable manner, and mitigating their impact is necessary for realizing reliable quantum computations. Moreover, the average error rates measured by randomized benchmarking and related protocols are not sensitive to the full impact of coherent errors and therefore do not reliably predict the global performance of quantum algorithms, leaving us unprepared to validate the accuracy of future large-scale quantum computations. Randomized compiling is a protocol designed to overcome these performance limitations by converting coherent errors into stochastic noise, dramatically reducing unpredictable errors in quantum algorithms and enabling accurate predictions of algorithmic performance from error rates measured via cycle benchmarking. In this work, we demonstrate significant performance gains under randomized compiling for the four-qubit quantum Fourier transform algorithm and for random circuits of variable depth on a superconducting quantum processor. Additionally, we accurately predict algorithm performance using experimentally measured error rates. Our results demonstrate that randomized compiling can be utilized to leverage and predict the capabilities of modern-day noisy quantum processors, paving the way forward for scalable quantum computing.

关键词： Quantum algorithms Quantum benchmarking Quantum control Quantum information with solid state qubits

来源：评论

学校读者我要写书评

暂无评论

OrigamiPlot: An R Package and Shiny Web App Enhanced Visualizations for Multivariate Data

arXiv

引用

arXiv 2024年

作者： Lu, Yiwen Tong, Jiayi Lei, Yuqing Sutton, Alex J. Chu, Haitao Levine, Lisa D. Lumley, Thomas Asch, David A. Duan, Rui Schmid, Christopher H. Chen, Yong Department of Biostatistics Epidemiology and Informatics Perelman School of Medicine University of Pennsylvania PhiladelphiaPA United States Department of Biostatistics Epidemiology and Informatics University of Pennsylvania Perelman School of Medicine PhiladelphiaPA United States The Graduate Group in Applied Mathematics and Computational Science School of Arts and Sciences University of Pennsylvania PhiladelphiaPA United States Department of Biostatistics Johns Hopkins Bloomberg School of Public Health BaltimoreMD United States Department of Population Health Sciences University of Leicester Leicester United Kingdom Division of Biostatistics and Health Data Science University of Minnesota MinneapolisMN United States Statistical Research and Innovation Global Biometrics and Data Management Pfizer Inc. New YorkNY United States Pregnancy and Perinatal Research Center Department of Obstetrics & Gynecology University of Pennsylvania Perelman School of Medicine PhiladelphiaPA United States Leonard Davis Institute of Health Economics PhiladelphiaPA United States Department of Statistics Faculty of Science University of Auckland Auckland New Zealand Division of General Internal Medicine University of Pennsylvania PhiladelphiaPA United States Department of Biostatistics Harvard T.H. Chan School of Public Health BostonMA United States Department of Biostatistics Brown University ProvidenceRI United States PhiladelphiaPA United States PhiladelphiaPA United States

We introduce OrigamiPlot, an open-source R package and Shiny web application designed to enhance the visualization of multivariate data. This package implements the origami plot, a novel visualization technique proposed by Duan et al. in 2023, which improves upon traditional radar charts by ensuring that the area of the connected region is invariant to the ordering of attributes, addressing a key limitation of radar charts. The software facilitates multivariate decision-making by supporting comparisons across multiple objects and attributes, offering customizable features such as auxiliary axes and weighted attributes for enhanced clarity. Through the R package and user-friendly Shiny interface, researchers can efficiently create and customize plots without requiring extensive programming knowledge. Demonstrated using network meta-analysis as a real-world example, OrigamiPlot proves to be a versatile tool for visualizing multivariate data across various fields. This package opens new opportunities for simplifying decision-making processes with complex data. © 2024, CC BY.

关键词： Data visualization

来源：评论

学校读者我要写书评

暂无评论

Gaussian differential privacy

arXiv

引用

arXiv 2019年

作者： Dong, Jinshuo Roth, Aaron Su, Weijie J. Graduate Group in Applied Mathematics and Computational Science University of Pennsylvania Department of Computer and Information Sciences University of Pennsylvania Department of Statistics Wharton School University of Pennsylvania

In the past decade, differential privacy has seen remarkable success as a rigorous and practical formalization of data privacy. This privacy definition and its divergence based relaxations, however, have several acknowledged weaknesses, either in handling composition of private algorithms or in analyzing important primitives like privacy amplification by subsampling. Inspired by the hypothesis testing formulation of privacy, this paper proposes a new relaxation of differential privacy, which we term "f-differential privacy" (f-DP). This notion of privacy has a number of appealing properties and, in particular, avoids difficulties associated with divergence based relaxations. First, f-DP faithfully preserves the hypothesis testing interpretation of differential privacy, thereby making the privacy guarantees easily interpretable. In addition, f-DP allows for lossless reasoning about composition in an algebraic fashion. Moreover, we provide a powerful technique to import existing results proven for the original differential privacy definition to f-DP and, as an application of this technique, obtain a simple and easy-to-interpret theorem of privacy amplification by subsampling for f-DP. In addition to the above findings, we introduce a canonical single-parameter family of privacy notions within the f-DP class that is referred to as "Gaussian differential privacy" (GDP), defined based on hypothesis testing of two shifted Gaussian distributions. GDP is the focal privacy definition among the family of f-DP guarantees due to a central limit theorem for differential privacy that we prove. More precisely, the privacy guarantees of any hypothesis testing based definition of privacy (including the original differential privacy definition) converges to GDP in the limit under composition. We also prove a Berry–Esseen style version of the central limit theorem, which gives a computationally inexpensive tool for tractably analyzing the exact composition of private algorithms. Taken

关键词： Gaussian distribution

来源：评论

学校读者我要写书评

暂无评论

Gravitational AdS to dS phase transition in five-dimensional Einstein-Maxwell-Gauss-Bonnet gravity

引用

Physical Review D 2020年第6期102卷 064008-064008页

作者： Daris Samart Phongpichit Channuie Department of Physics Faculty of Science Khon kaen University 123 Mitraphap road Khon Kaen 40002 Thailand School of Science Walailak University Thasala Nakhon Si Thammarat 80160 Thailand College of Graduate Studies Walailak University Thasala Nakhon Si Thammarat 80160 Thailand Research Group in Applied Computational and Theoretical Science (ACTS) Walailak University Thasala Nakhon Si Thammarat 80160 Thailand Thailand Center of Excellence in Physics Ministry of Education Bangkok 10400 Thailand

In this work, we revisit a toy model proposed by Camanho et al. [J. High Energy Phys. 10 (2015) 179] and extensively study the possible existence of gravitational phase transition from AdS to dS geometries by adding the Maxwell field as an impurity substitution. We show that the phase transitions proceed via the bubble nucleation of spherical thin shells described by different branches of the solution which host a black hole in the interior. In order to demonstrate the existence of the phase transition, we examine how the free energy and temperature depend on the higher-order gravity coupling (λ) indicating the possibility of thermalon-mediated phase transition. We observe that the phase transitions of the charged case are possible in which the required (maximum) temperature is lower than that of the neutral case. Interestingly, we also discover that the critical temperature and the coupling λ of the phase transitions are modified when having the charge. Notably, our results agree with the claim that the generalized gravitational phase transition is a generic behavior of the higher-order gravity theories even when the matter field is added.

关键词： Alternative gravity theories General relativity equations & solutions General relativity formalism

来源：评论

学校读者我要写书评

暂无评论

Optimized fermionic SWAP networks with equivalent circuit averaging for QAOA

arXiv

引用

arXiv 2021年

作者： Hashim, Akel Rines, Rich Omole, Victory Naik, Ravi K. Kreikebaum, John Mark Santiago, David I. Chong, Frederic T. Siddiqi, Irfan Gokhale, Pranav Quantum Nanoelectronics Laboratory Department of Physics University of California at Berkeley BerkeleyCA94720 United States Graduate Group in Applied Science and Technology University of California at Berkeley BerkeleyCA94720 United States Computational Research Division Lawrence Berkeley National Lab BerkeleyCA94720 United States Super.tech ChicagoIL60615 United States Materials Sciences Division Lawrence Berkeley National Lab BerkeleyCA94720 United States University of Chicago ChicagoIL60637 United States

The fermionic SWAP network is a qubit routing sequence that can be used to efficiently execute the Quantum Approximate Optimization Algorithm (QAOA). Even with a minimally-connected topology on an n-qubit processor, this routing sequence enables O(n2) operations to execute in O(n) steps. In this work, we optimize the execution of fermionic SWAP networks for QAOA through two techniques. First, we take advantage of an overcomplete set of native hardware operations in order to decompose the relevant quantum gates and SWAP networks in a manner which minimizes circuit depth and maximizes gate cancellation. Second, we introduce Equivalent Circuit Averaging, which randomizes over degrees of freedom in the quantum circuit compilation to reduce the impact of systematic coherent errors. Our techniques are experimentally validated on the Advanced Quantum Testbed through the execution of QAOA circuits for finding the ground state of two- and four-node Sherrington–Kirkpatrick spin-glass models with various randomly sampled parameters. We observe a ∼ 60% average reduction in error (total variation distance) for QAOA of depth p = 1 on four transmon qubits on a superconducting quantum processor. Copyright © 2021, The Authors. All rights reserved.

关键词： Degrees of freedom (mechanics)

来源：评论

学校读者我要写书评

暂无评论

Traversable wormholes in f(R) massive gravity

引用

Physical Review D 2020年第8期102卷 084026-084026页

作者： Takol Tangphati Auttakit Chatrabhuti Daris Samart Phongpichit Channuie Department of Physics Faculty of Science Chulalongkorn University Bangkok 10330 Thailand Department of Physics Faculty of Science Khon Kaen University Khon Kaen 40002 Thailand School of Science Walailak University Nakhon Si Thammarat 80160 Thailand College of Graduate Studies Walailak University Nakhon Si Thammarat 80160 Thailand Research Group in Applied Computational and Theoretical Science (ACTS) Walailak University Nakhon Si Thammarat 80160 Thailand Thailand Center of Excellence in Physics Ministry of Higher Education Science Research and Innovation Bangkok 10400 Thailand

In this work, the study of traversable wormholes in f(R) massive gravity with the function f(R)=R+α1Rn, where α1 and n are arbitrary constants, is considered. We choose the shape function of the form b(r)=rexp(−α(r−r0)) with α and r0 being an arbitrary constant and a radius of the wormhole throat, respectively. Here α affects the radius of curvature of the wormhole. We consider a spherically symmetric and static wormhole metric and derive field equations. Moreover, we visualize the wormhole geometry using embedding diagrams. Furthermore, we check the null, weak, dominant, and strong energy conditions at the wormhole throat with a radius r0 invoking three types of redshift functions, Φ=constant, γ1/r, log(1+γ2/r) with γ1 and γ2 are arbitrary real constants. We also compute the volume integral quantifier to calculate the amount of the exotic matter near the constructed wormhole throat.

关键词： Alternative gravity theories General relativity equations & solutions General relativity formalism

来源：评论

学校读者我要写书评

暂无评论

WONDER: Weighted one-shot distributed ridge regression in high dimensions

arXiv

引用

arXiv 2019年

作者： Dobriban, Edgar Sheng, Yue Wharton Statistics Department University of Pennsylvania 3730Walnut Street PhiladelphiaPA United States Graduate Group in Applied Mathematics and Computational Science Department of Mathematics University of Pennsylvania

In many areas, practitioners need to analyze large datasets that challenge conventional single-machine computing. To scale up data analysis, distributed and parallel computing approaches are increasingly needed. Here we study a fundamental and highly important problem in this area: How to do ridge regression in a distributed computing environment? Ridge regression is an extremely popular method for supervised learning, and has several optimality properties, thus it is important to study. We study one-shot methods that construct weighted combinations of ridge regression estimators computed on each machine. By analyzing the mean squared error in a high dimensional random-effects model where each predictor has a small effect, we discover several new phenomena. Infinite-worker limit: The distributed estimator works well for very large numbers of machines, a phenomenon we call "infinite-worker limit". Optimal weights: The optimal weights for combining local estimators sum to more than unity, due to the downward bias of ridge. Thus, all averaging methods are suboptimal. We also propose a new Weighted ONe-shot DistributEd Ridge regression (WONDER) algorithm. We test WONDER in simulation studies and using the Million Song Dataset as an example. There it can save at least 100x in computation time, while nearly preserving test accuracy. Copyright © 2019, The Authors. All rights reserved.

关键词： Regression analysis

来源：评论

学校读者我要写书评

暂无评论

Relationship between changing malaria burden and low birth weight in sub-Saharan Africa: A difference-in-differences study via a pair-of-pairs approach

arXiv

引用

arXiv 2020年

作者： Heng, Siyu O'Meara, Wendy P. Simmons, Ryan A. Small, Dylan S. Graduate Group in Applied Mathematics and Computational Science School of Arts and Sciences University of Pennsylvania PhiladelphiaPA United States Department of Statistics The Wharton School University of Pennsylvania PhiladelphiaPA United States Global Health Institute School of Medicine Duke University DurhamNC United States Department of Biostatistics and Bioinformatics School of Medicine Duke University DurhamNC United States

According to the World Health Organization (WHO), in 2018, an estimated 228 million malaria cases occurred worldwide with most cases occurring in sub-Saharan Africa. Scale-up of vector control tools coupled with increased access to diagnosis and effective treatment has resulted in a large decline in malaria prevalence in some areas, but other areas have seen little change. Although interventional studies demonstrate that preventing malaria during pregnancy can reduce the low birth weight (i.e., child's birth weight 2−10) > 0.4) to a low rate (PfPR2−10 Copyright © 2020, The Authors. All rights reserved.

关键词： Diseases

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：