检索结果-内蒙古大学图书馆

Density functional theory investigation of electronic structure and muon hyperfine interaction in isolated adenine and thymine

引用

Interactions 2024年第1期245卷 1-14页

作者： Zaharim, Wan Nurfadhilah Sulaiman, Shukri Jamaludin, Ammaina Rozak, Harison Watanabe, Isao Department of Chemical Sciences Faculty of Science and Technology Universiti Kebangsaan Malaysia Selangor Bangi43600 Malaysia Nuclear Structure Research Group RIKEN Nishina Center for Accelerator Based Science 2-1 Hirosawa Wako Saitama351-0198 Japan Physics Section School of Distance Education Universiti Sains Malaysia Pulau Pinang Minden11800 Malaysia Computational Physics Laboratory School of Distance Education Universiti Sains Malaysia Pulau Pinang Minden11800 Malaysia Innovative Global Program College of Engineering Shibaura Institute of Technology Saitama337-8570 Japan

In DFT calculation, a basis set is an important factor in determining the quality of results, especially for hyperfine interaction where changes in the local geometry and electronic structure can have a big impact. The use of extensive basis sets is always desirable and is expected to produce better results. However, for DNA molecules of more than 10 base-pairs, all-electron geometry optimization calculation using large basis sets such as 6-311++G(d,p) is prohibitively difficult even on a supercomputer. An alternative is to use smaller basis sets such as 6-31G which is used in this work. Thus, the objective of the work reported here is to determine whether 6-31G basis set is suitable to be used to study muon hyperfine interaction in short DNA molecule. It is found that in comparison with 6-311++G(d,p), 6-31G does not change the ranking of muon sites stability in isolated adenine and thymine. Furthermore, the 6-31G calculated muon HFCCs are slightly closer to the experimental values. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2024.

关键词： Electronic structure

来源：评论

学校读者我要写书评

暂无评论

RTM process simulation by using XFEM and level set method

RTM process simulation by using XFEM and level set method

引用

18th International Conference on Composites Materials, ICCM 2011

作者： Jung, Yeonhee Han, Woo-Suck Vautrin, Alain Kim, Seung Jo LCG/UMR 5148 Centre SMS Ecole Nationale Supérieure des Mines de Saint-Etienne 42023 Saint-Etienne France Interdisciplinary Program in Computational Science and Technology Seoul National University Seoul 151-742 Korea Republic of School of Mechanical and Aerospace Engineering Seoul National University Seoul 151-742 Korea Republic of

A numerical simulation program for Resin Transfer Molding (RTM) manufacturing process is developed using eXtended Finite Element Method (XFEM) combined with the level set method. The level set method is used to track the resin flow front at each time step. XFEM allows to obtaining better accuracy of the resin pressure field in the flow front region than the classical FEM. The enriched shape functions of XFEM are derived by using the level set values of the front region. Finally, the level set values are calculated by an implicit characteristic Galerkin method. The numerical fill time is compared with the analytical solution to validate this program.

关键词： Resin transfer molding

来源：评论

学校读者我要写书评

暂无评论

Interference mitigation of adjacent radio frequency signals on a flexible software-defined radio testbed platform 55

Interference mitigation of adjacent radio frequency signals ...

引用

55th Annual International Telemetering Conference: Cultivating the Next Generation of Range Engineers, ITC 2019

作者： Elahi, Mirza M. Sandoval, Jose C. Gonzalez, Virgilio Corral, Pabel Yasuda, Susumu Gonzalez, Virgilio Computational Science Program University of Texas at El Paso El PasoTX79968 United States Department of Electrical and Computer Engineering University of Texas at El Paso El PasoTX79968 United States U.S. Army Test and Evaluation Command White Sands Missile Range White SandsNM United States

ISBN: (纸本)9781713801887

The radio frequency (RF) spectrum is crowded with users and adjacent frequency users are facing an increase in interference from each other. The spectrum governing body Federal Communications Commission (FCC) has the difficult task of allocating spectral bands for new users for mobile devices using 4G LTE technology. Telemetry (TM) is affected by the adjacent band 4G LTE users in terms of signal degradation. To minimize the interference between adjacent frequency users, several methods can be used. A common but inefficient method separates adjacent band frequencies using guard bands which leaves a big portion of the spectrum unused. Alternatively, adjacent RF signals can be separated using digital filtering techniques with the signal of interest being unharmed and reducing the signal power of the interfering signal. A digital filtering technique includes bandpass filter (BPF) rejection, which has the ability to filter out adjacent interfering signals. This is accomplished by designing bandpass digital filters where the passband and stopband frequencies are adjusted to achieve maximum signal power and reject the interfering signal by reducing its power. A flexible software-defined radio testbed is set up to experiment and analyze this scenario with ease and effective measures. © 2019 International Foundation for Telemetering. All rights reserved.

关键词： Bandpass filters

来源：评论

学校读者我要写书评

暂无评论

Angular-Momentum-Dependent Orbital-Free Density Functional Theory

引用

Physical Review Letters 2013年第6期111卷 066402-066402页

作者： Youqi Ke Florian Libisch Junchao Xia Lin-Wang Wang Emily A. Carter Department of Mechanical and Aerospace Engineering Program in Applied and Computational Mathematics and Andlinger Center for Energy and the Environment Princeton University Princeton New Jersey 08544 USA Material Science Division Lawrence Berkeley National Laboratory Berkeley California 94720 USA

Orbital-free (OF) density functional theory (DFT) directly solves for the electron density rather than the wave function of many electron systems, greatly simplifying and enabling large scale first principles simulations. However, the required approximate noninteracting kinetic energy density functionals and local electron-ion pseudopotentials severely restrict the general applicability of conventional OFDFT. Here, we present a new generation of OFDFT called angular-momentum-dependent (AMD)-OFDFT to harness the accuracy of Kohn-Sham DFT and the simplicity of OFDFT. The angular momenta of electrons are explicitly introduced within atom-centered spheres so that the important ionic core region can be accurately described. In addition to conventional OF total energy functionals, we introduce a crucial nonlocal energy term with a set of AMD energies to correct errors due to the kinetic energy density functional and the local pseudopotential. We find that our AMD-OFDFT formalism offers substantial improvements over conventional OFDFT, as we show for various properties of the transition metal titanium.

关键词： DENSITY functional theory ELECTRON density KINETIC energy PSEUDOPOTENTIAL method TRANSITION metal compounds ELECTRON-ion collisions

来源：评论

学校读者我要写书评

暂无评论

A Neuro-Inspired Approach to Solve a Simultaneous Location and Mapping Task Using Shared Information in Multiple Robots Systems 15

A Neuro-Inspired Approach to Solve a Simultaneous Location a...

引用

15th International Conference on Control, Automation, Robotics and Vision, ICARCV 2018

作者： Menezes, Matheus Chaves De Freitas, Edison Pignaton Cheng, Sen De Oliveira, Alexandre Cesar Muniz De Almeida Ribeiro, Paulo Rogerio Graduate Program on Computer Science Federal University of Maranhão Sao Luis Brazil Computational Neuroscience Ruhr University Bochum Institute for Neural Computation Bochum Germany Department of Informatics Federal University of Maranhão Sao Luis Maranhao Brazil Department of Computer Engineering Federal University of Maranhão Sao Luis Maranhao Brazil

ISBN: (纸本)9781538695821

This paper presents a neuro-inspired mapping approach that uses partial information shared by multiple robots to reduce the time to create a map of an entire environment. Robots using a neurobiologically inspired algorithm, namely RatSLAM, map an environment sharing video information among themselves. RatSLAM, which is based on the navigation system present in the hippocampus of rodents' brain, has been widely used on simultaneous localization and mapping (SLAM) problem. This proposal has been able to generate suitable maps mainly when there is redundant information, e.g. a scene is seen more than once, since this fact activates local view cells that inject activity inside the pose cells via an excitatory link. The work here reported extends this approach by merging partial information acquired by multiple robots. The results from the performed experiments show that the final map built by two robots with shared information is similar to one built by two robots performing the same mapping task individually, i.e. without sharing information. However, the time spent to generate the whole map with the proposed shared approach was smaller than the one without the shared information. Thus, the current approach allows creating a complete map of an environment within a reduced time using multiple robots. © 2018 IEEE.

关键词： Mapping

来源：评论

学校读者我要写书评

暂无评论

Stability of stochastic gradient descent on nonsmooth convex losses 20

Stability of stochastic gradient descent on nonsmooth convex...

引用

Proceedings of the 34th International Conference on Neural Information Processing Systems

作者： Raef Bassily Vitaly Feldman Cristóbal Guzmán Kunal Talwar Department of Computer Science & Engineering The Ohio State University Apple Pontificia Universidad Católica de Chile Institute for Mathematical and Computational Engineering ANID – Millennium Science Initiative Program Millennium Nucleus Center for the Discovery of Structures in Complex Data

ISBN: (纸本)9781713829546

Uniform stability is a notion of algorithmic stability that bounds the worst case change in the model output by the algorithm when a single data point in the dataset is replaced. An influential work of Hardt et al. [20] provides strong upper bounds on the uniform stability of the stochastic gradient descent (SGD) algorithm on sufficiently smooth convex losses. These results led to important progress in understanding of the generalization properties of SGD and several applications to differentially private convex optimization for smooth *** work is the first to address uniform stability of SGD on nonsmooth convex losses. Specifically, we provide sharp upper and lower bounds for several forms of SGD and full-batch GD on arbitrary Lipschitz nonsmooth convex losses. Our lower bounds show that, in the nonsmooth case, (S)GD can be inherently less stable than in the smooth case. On the other hand, our upper bounds show that (S)GD is sufficiently stable for deriving new and useful bounds on generalization error. Most notably, we obtain the first dimension-independent generalization bounds for multi-pass SGD in the nonsmooth case. In addition, our bounds allow us to derive a new algorithm for differentially private nonsmooth stochastic convex optimization with optimal excess population risk. Our algorithm is simpler and more efficient than the best known algorithm for the nonsmooth case [16].

关键词：

来源：评论

学校读者我要写书评

暂无评论

Rewriting regulatory DNA to dissect and reprogram gene expression

引用

Cell 2025年

作者： Martyn, Gabriella E. Montgomery, Michael T. Jones, Hank Guo, Katherine Doughty, Benjamin R. Linder, Johannes Bisht, Deepa Xia, Fan Cai, Xiangmeng S. Chen, Ziwei Cochran, Kelly Lawrence, Kathryn A. Munson, Glen Pampari, Anusri Fulco, Charles P. Sahni, Nidhi Kelley, David R. Lander, Eric S. Kundaje, Anshul Engreitz, Jesse M. Department of Genetics Stanford University School of Medicine Stanford 94305 CA United States Basic Science and Engineering Initiative Stanford Children's Health Betty Irene Moore Children's Heart Center Stanford 94305 CA United States Calico Life Sciences LLC South San Francisco 94080 CA United States Department of Genitourinary Medical Oncology Division of Cancer Medicine The University of Texas MD Anderson Cancer Center Houston 77030 TX United States Department of Genomic Medicine The University of Texas MD Anderson Cancer Center Houston 77030 TX United States Department of Epigenetics and Molecular Carcinogenesis The University of Texas MD Anderson Cancer Center Houston 77230 TX United States Department of Bioengineering Stanford University Stanford 94305 CA United States Department of Computer Science Stanford University Stanford 94305 CA United States Novo Nordisk Foundation Center for Genomic Mechanisms of Disease Broad Institute of MIT and Harvard Cambridge 02142 MA United States Gene Regulation Observatory Broad Institute of MIT and Harvard Cambridge 02142 MA United States Broad Institute of MIT and Harvard Cambridge 02142 MA United States Department of Bioinformatics and Computational Biology The University of Texas MD Anderson Cancer Center Houston 77230 TX United States Quantitative and Computational Biosciences Program Baylor College of Medicine Houston 77030 TX United States Department of Biology MIT Cambridge 02139 MA United States Department of Systems Biology Harvard Medical School Boston 02115 MA United States Stanford Cardiovascular Institute Stanford University Stanford 94305 CA United States

Regulatory DNA provides a platform for transcription factor binding to encode cell-type-specific patterns of gene expression. However, the effects and programmability of regulatory DNA sequences remain difficult to map or predict. Here, we develop variant effects from flow-sorting experiments with CRISPR targeting screens (Variant-EFFECTS) to introduce hundreds of designed edits to endogenous regulatory DNA and quantify their effects on gene expression. We systematically dissect and reprogram 3 regulatory elements for 2 genes in 2 cell types. These data reveal endogenous binding sites with effects specific to genomic context, transcription factor motifs with cell-type-specific activities, and limitations of computational models for predicting the effect sizes of variants. We identify small edits that can tune gene expression over a large dynamic range, suggesting new possibilities for prime-editing-based therapeutics targeting regulatory DNA. Variant-EFFECTS provides a generalizable tool to dissect regulatory DNA and to identify genome editing reagents that tune gene expression in an endogenous context. © 2025 Elsevier Inc.

关键词： CRISPR enhancers gene regulation high-throughput screening non-coding variants predictive models prime editing RNA FlowFISH sequence design transcription factors

来源：评论

学校读者我要写书评

暂无评论

Geospatial Intelligence for Individual Crop Detection and Anomaly Monitoring

Geospatial Intelligence for Individual Crop Detection and An...

引用

IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Freda Elikem Dorbu Leila Hashemi-Beni Department of Computational Data Science and Engineering North Carolina A&T State University Department of Built Environment Geomatics Program North Carolina A&T State University

Acquisition of geospatial data by UAV has been acknowledged as an effective method of attaining reliable and quick high-resolution remote sensing data for analysis and decision-making in different applications such as agriculture as it produces timely results, and it is affordable. UAVs coupled with other technological applications such as robotics, computing and deep learning facilitate the execution of precision agriculture. The execution of individual tree identification enables vivid description of the crop peak height and canopy for accurate estimation of issues related to crop growth such as biomass reduction, lodging, and stunted growth. A geospatial intelligence algorithm was developed to determine the lodging state of the crops. First, the optical imagery (RGB) was automatically annotated using maximum likelihood classification algorithm for faster acquisition of ground truth and to verify with the manually annotated image data for deep learning training. The acquired images were split for training of fine-tuned three deep learning methods including U-net, U-net++ and attention-residual Unet. The results show that each model has the tendency to learn patterns in data and predict lodged crops. Results from the analysis were validated by visual assessment of the time-series aerial images and validation data acquired from the ground truth data using k-fold cross validation approach.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Artificial neural network approach for turbulence models: A local framework

arXiv

引用

arXiv 2021年

作者： Xie, Chenyue Xiong, Xiangming Wang, Jianchun Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Department of Mechanics and Aerospace Engineering Southern University of Science and Technology Shenzhen518055 China

A local artificial neural network (LANN) framework is developed for turbulence modeling. The Reynolds-averaged Navier-Stokes (RANS) unclosed terms are reconstructed by artificial neural network (ANN) based on the local coordinate system which is orthogonal to the curved walls. We verify the proposed model for the flows over periodic hills. The correlation coefficients of the RANS unclosed terms predicted by the LANN model can be made larger than 0.96 in an a priori analysis, and the relative error of the unclosed terms can be made smaller than 18%. In an a posteriori analysis, detailed comparisons are made on the results of RANS simulations using the LANN and Spalart-Allmaras (SA) models. It is shown that the LANN model performs better than the SA model in the prediction of the average velocity, wall-shear stress and average pressure, which gives the results that are essentially indistinguishable from the direct numerical simulation (DNS) data. The LANN model trained in low Reynolds number Re = 2800 can be directly applied in the cases of high Reynolds numbers Re = 5600, 10595, 19000, 37000 with accurate predictions. Furthermore, the LANN model is verified for flows over periodic hills with varying slopes. These results suggest that the LANN framework has a great potential to be applied to complex turbulent flows with curved *** Codes 76F40, 76F55, 76N99 Copyright © 2021, The Authors. All rights reserved.

关键词： Neural networks

来源：评论

学校读者我要写书评

暂无评论

Orchard: building large cancer phylogenies using stochastic combinatorial search

arXiv

引用

arXiv 2023年

作者： Kulman, Ethan Kuang, Rui Morris, Quaid Computational and Systems Biology Program Sloan Kettering Institute New YorkNY United States Department of Computer Science and Engineering University of Minnesota MinneapolisMN United States

Phylogenies depicting the evolutionary history of genetically heterogeneous subpopulations of cells from the same cancer, i.e., cancer phylogenies, offer valuable insights about cancer development and guide treatment strategies. Many methods exist that reconstruct cancer phylogenies using point mutations detected with bulk DNA sequencing. However, these methods become inaccurate when reconstructing phylogenies with more than 30 mutations, or, in some cases, fail to recover a phylogeny altogether. Here, we introduce Orchard, a cancer phylogeny reconstruction algorithm that is fast and accurate using up to 1000 mutations. Orchard samples without replacement from a factorized approximation of the posterior distribution over phylogenies, a novel result derived in this paper. Each factor in this approximate posterior corresponds to a conditional distribution for adding a new mutation to a partially built phylogeny. Orchard optimizes each factor sequentially, generating a sequence of incrementally larger phylogenies that ultimately culminate in a complete tree containing all mutations. Our evaluations demonstrate that Orchard outperforms state-of-the-art cancer phylogeny reconstruction methods in reconstructing more plausible phylogenies across 90 simulated cancers and 14 B-progenitor acute lymphoblastic leukemias (B-ALLs). Remarkably, Orchard accurately reconstructs cancer phylogenies using up to 1,000 mutations. Additionally, we demonstrate that the large and accurate phylogenies reconstructed by Orchard are useful for identifying patterns of somatic mutations and genetic variations among distinct cancer cell subpopulations. © 2023, CC BY.

关键词： Plant 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：