检索结果-内蒙古大学图书馆

Hopf Solitons in Helical and Conical Backgrounds of Chiral Magnetic Solids

Physical Review Letters 2020年第5期125卷 057201-057201页

作者： Robert Voinescu Jung-Shen B. Tai (戴榮身) Ivan I. Smalyukh Department of Physics University of Colorado Boulder Colorado 80309 USA Materials Science and Engineering Program Soft Materials Research Center and Department of Electrical Computer and Energy Engineering University of Colorado Boulder Colorado 80309 USA Renewable and Sustainable Energy Institute National Renewable Energy Laboratory and University of Colorado Boulder Colorado 80309 USA

Three-dimensional topological solitons attract a great deal of interest in fields ranging from particle physics to cosmology, but remain experimentally elusive in solid-state magnets. Here we numerically predict magnetic heliknotons, an embodiment of such nonzero-Hopf-index solitons localized in all spatial dimensions while embedded in a helical or conical background of chiral magnets. We describe conditions under which heliknotons emerge as metastable or ground-state localized nonsingular structures with fascinating knots of magnetization field in widely studied materials. We demonstrate magnetic control of three-dimensional spatial positions of such solitons, as well as show how they interact to form moleculelike clusters and possibly even crystalline phases comprising three-dimensional lattices of such solitons with both orientational and positional order. Finally, we discuss both fundamental importance and potential technological utility of magnetic heliknotons.

关键词： Dzyaloshinskii-Moriya interaction Skyrmions Chiral magnets Micromagnetic modeling Topology

来源：评论

学校读者我要写书评

暂无评论

Identifying and Anticipating Cyberattacks That Could Cause Physical Damage to Industrial Control Systems

引用

IEEE Power and Energy Technology Systems Journal 2019年第4期6卷 172-182页

作者： Angle, Matthew G. Madnick, Stuart Kirtley, James L. Khan, Shaharyar Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA02139 United States Sloan School of Management School of Engineering Massachusetts Institute of Technology CambridgeMA02139 United States System Design and Management Program Massachusetts Institute of Technology CambridgeMA02139 United States

Physical control systems are increasingly controlled by reconfigurable, network-enabled devices to increase flexibility and ease commissioning and maintenance. Such capability creates vulnerabilities. Devices may be remotely reprogrammed by a malicious actor to act in unintended ways, causing physical damage to mechanical equipment, infrastructure, and life and limb. In this paper, past examples of actual damage to cyber-physical systems are shown, threats posed by software-controlled variable frequency drives (VFDs) are analyzed, and a small-scale version of an attack on ubiquitous VFD equipment is demonstrated. © 2014 IEEE.

关键词： Embedded systems

来源：评论

学校读者我要写书评

暂无评论

Potential Impact of Social Media to Support Government Services in Jakarta Smart City 3

Potential Impact of Social Media to Support Government Servi...

引用

3rd International Conference on Information Management and Technology, ICIMTech 2018

作者： Didik Madyatmadja, Evaristus Abdurachman, Edi Gaol, Ford Lumban Pudjianto, Bonifasius W. Hapsara, Manik Information Systems Department Computer Science Department BINUS Graduate Program-Doctor of Computer Science Jakarta11480 Indonesia Computer Science Department Bina Nusantara University BINUS Graduate Program-Doctor of Computer Science Jakarta11480 Indonesia Indonesian Creative Economy Agency Jakarta Indonesia University of New South Wales School of Engineering and Information Technology Australia

ISBN: (纸本)9781538658215

The purpose of this initiative is to ensure that citizens use social media to access information about the state of the city. Social media application offers benefits in the form of a channel of communication between the community and the government or the group that has public interest. Through this application, the public could channel complaints about public services. Perception becomes the important key for this condition because user action is determined by their perception toward the government e-services. The result of standard measurement for customer satisfaction on government organization is used to help find the weakness of the service and correct it. The interface is made to be more user-friendly to ensure the effective service. So, it is necessary to develop the system continuously. Perceived quality is one of the important determinants of the success of social media application, therefore needs identification of the user's perception and expectations and involving becomes the key to success besides the good quality that will increase the trust and satisfaction of users. Evaluation of social media applications is needed so that it can provide recommendations to the provincial government of DKI Jakarta related to what things can be done to improve community service. © 2018 IEEE.

关键词： Smart city

来源：评论

学校读者我要写书评

暂无评论

Big Data Governance for Building A Smart Cities

Big Data Governance for Building A Smart Cities

引用

International Conference on ICT For Smart Society (ICISS)

作者： Novan Zulkarnain Raymond Kosala Benny Ranti Suhono Harso Supangkat Computer Science Department BINUS Graduate Program Doctor of Computer Science Information Systems Department Bina Nusantara University Jakarta Indonesia Computer Science Department Bina Nusantara University Jakarta Indonesia Computer Science Department Universitas Indonesia Depok Indonesia School of Electrical and Informatics Engineering Institute of Technology Bandung Bandung Indonesia

There have been many studies conducted related to Smart City, IT Governance and Big Data. In this study aims to find out how the relationship between the three and how to form a framework to explain it. The methodology used is qualitative by looking for some literature on smart city framework, IT Governance framework, and a Big Data framework. From these results, an overall picture of the relationship between the three is concluded, where Big Data has a role in IT Governance. and also the relationship of IT Governance to the realization of Smart City. And the final results of this study produce a framework to explain the relationship between Smart City, IT Governance and Big Data.

关键词：

来源：评论

学校读者我要写书评

暂无评论

UNDERSTANDING THE PERCEPTION OF COVID-19 POLICIES BY MINING A MULTILANGUAGE TWITTER DATASET

arXiv

引用

arXiv 2020年

作者： Lopez, Christian E. Vasu, Malolan Gallemore, Caleb Computer Science Department Lafayette College EastonPA18042 United States Mechanical Engineering Department Lafayette College EastonPA18042 United States International Affairs Program Lafayette College EastonPA18042 United States

The objective of this work is to explore popular discourse about the COVID-19 pandemic and policies implemented to manage it. Using Natural Language Processing, Text Mining, and Network Analysis to analyze corpus of tweets that relate to the COVID-19 pandemic, we identify common responses to the pandemic and how these responses differ across time. Moreover, insights as to how information and misinformation were transmitted via Twitter, starting at the early stages of this pandemic, are presented. Finally, this work introduces a dataset of tweets collected from all over the world, in multiple languages, dating back to January 22nd, when the total cases of reported COVID-19 were below 600 worldwide. The insights presented in this work could help inform decision makers in the face of future pandemics, and the dataset introduced can be used to acquire valuable knowledge to help mitigate the COVID-19 pandemic. Copyright © 2020, The Authors. All rights reserved.

关键词： Social networking (online)

来源：评论

学校读者我要写书评

暂无评论

Resilience enhancements of power distribution lines using computer vision technology

Resilience enhancements of power distribution lines using co...

引用

2019 Institute of Industrial and Systems Engineers Annual Conference and Expo, IISE 2019

作者： Alam, Md Morshedul Tokgoz, Berna Eren Zhu, Zanbo Zhang, Jing Hwang, Seokyon Department of Industrial Engineering Lamar University BeaumontTX77710 United States Department of Computer Science Lamar University BeaumontTX77710 United States Construction Management Program Lamar University BeaumontTX77710 United States

ISBN: (纸本)9781713814092

The electric power distribution network is one of the infrastructures that experience frequent and large-scale damages caused by storms. In particularly, the wooden poles carrying power from local substations to customers are found to be extremely vulnerable to storms. There are several reasons for pole failure such as pole inclination angle, decay over the time, falling trees or branches, etc. Among them, the pole inclination angle is assumed to have significant impacts and not much addressed in existing literature. However, pole failure inevitably leads to power outages for hours, days, or even weeks, depending on the intensity of storms and the severity of damages. A methodology was developed by utilizing the deep learning-based vision technologies integrated with a drone system to determine the pole inclination angle. Then, the angular deflection of a pole was determined by applying wind and gravitational forces. Resilience conditions of a pole are determined based on the angular deflection. A cost-benefit analysis was performed to compare losses and savings for different pole conditions. Different strategies were examined based on an angular deflection during the service life of a pole. © 2019 IISE Annual Conference and Expo 2019. All rights reserved.

关键词： Cost benefit analysis

来源：评论

学校读者我要写书评

暂无评论

Question-Answering System Extracts Information on Injection Drug Use from Clinical Notes

arXiv

引用

arXiv 2023年

作者： Mahbub, Maria Goethert, Ian Danciu, Ioana Knight, Kathryn Srinivasan, Sudarshan Tamang, Suzanne Rozenberg-Ben-Dror, Karine Solares, Hugo Martins, Susana Trafton, Jodie Begoli, Edmon Peterson, Gregory D. Cyber Resilience and Intelligence Division Oak Ridge National Laboratory Oak RidgeTN United States Information Technology Services Division Oak Ridge National Laboratory Oak RidgeTN United States Computational Sciences and Engineering Division Oak Ridge National Laboratory Oak RidgeTN United States Department of Biomedical Informatics Vanderbilt University NashvilleTN United States Program Evaluation and Resource Center Office of Mental Health and Suicide Prevention Department of Veterans Affairs United States Department of Medicine Stanford University School of Medicine StanfordCA United States Veterans Affairs Great Lakes Health Care System WestchesterIL United States Department of Electrical Engineering and Computer Science University of Tennessee Knoxville KnoxvilleTN United States

Background: Injection drug use (IDU) is a dangerous health behavior that increases mortality and morbidity. Identifying IDU early and initiating harm reduction interventions can benefit individuals at risk. However, extracting IDU behaviors from patients’ electronic health records (EHR) is difficult because there is no International Classification of Disease (ICD) code and the only place IDU information can be indicated is unstructured free-text clinical notes. Although natural language processing can efficiently extract this information from unstructured data, there are no validated tools. Methods: To address this gap in clinical information, we design and demonstrate a question-answering (QA) framework to extract information on IDU from clinical notes. Our framework involves two main steps: (1) generating a gold-standard QA dataset and (2) developing and testing the QA model. We utilize 2323 clinical notes of 1145 patients sourced from the VA Corporate Data Warehouse to construct the gold-standard dataset for developing and evaluating the QA model. We also demonstrate the QA model’s ability to extract IDU-related information on temporally out-of-distribution data. Results: Here we show that for a strict match between gold-standard and predicted answers, the QA model achieves 51.65% F1 score. For a relaxed match between the gold-standard and predicted answers, the QA model obtains 78.03% F1 score, along with 85.38% Precision and 79.02% Recall scores. Moreover, the QA model demonstrates consistent performance when subjected to temporally out-of-distribution data. Conclusions: Our study introduces a QA framework designed to extract IDU information from clinical notes, aiming to enhance the accurate and efficient detection of people who inject drugs, extract relevant information, and ultimately facilitate informed patient care. © 2023, CC BY-NC-ND.

关键词： Data warehouses

来源：评论

学校读者我要写书评

暂无评论

Coherent growth and characterization of van der Waals 1T−VSe2 layers on GaAs(111)B using molecular beam epitaxy

引用

Physical Review Materials 2020年第8期4卷 084002-084002页

作者： Tiancong Zhu Dante J. O’Hara Brenton A. Noesges Menglin Zhu Jacob J. Repicky Mark R. Brenner Leonard J. Brillson Jinwoo Hwang Jay A. Gupta Roland K. Kawakami Department of Physics The Ohio State University Columbus Ohio 43210 USA Program in Materials Science and Engineering University of California Riverside California 92521 USA Materials Science Division Lawrence Livermore National Laboratory Livermore California 94550 USA Department of Materials Science and Engineering The Ohio State University Columbus Ohio 43210 USA Department of Electrical and Computer Engineering The Ohio State University Columbus Ohio 43210 USA Semiconductor and Epitaxy Analysis Laboratory The Ohio State University Columbus Ohio 43210 USA

We report epitaxial growth of vanadium diselenide (VSe2) thin films in the octahedrally coordinated (1T) structure on GaAs(111)B substrates by molecular beam epitaxy. Film thickness from a single monolayer (ML) up to 30 ML is demonstrated. Structural and chemical studies using x-ray diffraction, transmission electron microscopy, scanning tunneling microscopy, and x-ray photoelectron spectroscopy indicate high-quality thin films. Further studies show that monolayer VSe2 films on GaAs are not air stable and are susceptible to oxidation within a matter of hours, which indicates that a protective capping layer should be employed for device applications. This work demonstrates that VSe2, a candidate van der Waals material for possible spintronic and electronic applications, can be integrated with III-V semiconductors via epitaxial growth for two- and three-dimensional hybrid devices.

关键词： Chemical bonding Growth Ferromagnets III-V semiconductors Transition metal dichalcogenides Molecular beam epitaxy Reflection high-energy electron diffraction

来源：评论

学校读者我要写书评

暂无评论

Scalable Metagrating for Efficient Ultrasonic Focusing

引用

Physical Review Applied 2021年第6期16卷 064014-064014页

作者： Yan Kei Chiang Li Quan Yugui Peng Shahrokh Sepehrirahnama Sebastian Oberst Andrea Alù David A. Powell School of Engineering and Information Technology University of New South Wales Canberra ACT 2610 Australia Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Centre for Audio Acoustics and Vibration University of Technology Sydney Broadway NSW 2007 Australia Physics Program Graduate Center City University of New York New York New York 10016 USA

Acoustic metalenses have been pursued over the past decades due to their pivotal role in a wide variety of applications. Recent research efforts have demonstrated that, at ultrasonic regimes, acoustic levitation can be realized with standing waves, which are created by the interference between incoming and reflected focused waves. However, the conventional gradient-metasurface approach to focus ultrasonic waves is complex, leading to poor scalability. In this work, we propose a design principle for ultrasonic metalenses, based on metagratings—arrays of discrete scatters with coarser features than gradient metasurfaces. We achieve beam focusing by locally controlling the excitation of a single diffraction order with the use of metagratings, with geometry adiabatically varying over the lens aperture. We show that our metalens can effectively focus impinging ultrasonic waves to a focal point with a full width at half maximum of 0.364 of the wavelength. The focusing performance of the metalens is demonstrated experimentally, validating our proposed approach. This metagrating approach to focusing can be adopted for different operating frequencies by scaling the size of the structure, which has coarse features suitable for high-frequency designs, with potential applications ranging from biomedical science to nondestructive testing.

关键词： Acoustic measurements Acoustic metamaterials Acoustic modeling Acoustic wave phenomena Beam optics Ultrasonics Bloch-Floquet theorem Ultrasound techniques

来源：评论

学校读者我要写书评

暂无评论

Automatic Food Leftover Estimation in Tray Box Using Image Segmentation

Automatic Food Leftover Estimation in Tray Box Using Image S...

引用

International Conference on Sustainable Information Engineering and Technology (SIET)

作者： Yuita Arum Sari Ratih Kartika Dewi Jaya Mahar Maligan Anindya Sasri Ananta Sigit Adinugroho Computer Vision Research Group Faculty of Computer Science Malang Indonesia Mobile Game and Multimedia Research Group Faculty of Computer Science Malang Indonesia Food Nutrition Study Program Faculty of Agricultural Technology Malang Indonesia

Nutritional food is the most important aspect for people to fulfil their daily needs, but nowadays, the change of lifestyle can affect the style of food consumption, for instance leaving food when they take a meal. Besides, food leftover causes loss of consumed nutrients. We took an observation in a canteen in Faculty of Agricultural Technology in University of Brawijaya produces lost of food about 1,142.5 gram per day. To prevent the amount of food waste, this paper proposes an early stage framework to create an automatic leftover estimation method using image segmentation based on color channel. So that, we can optimize of the amount of food served and avoid loss food nutritions hereinafter. We experimented in two types of background of tray box: black and gray, then an automatic cropping process based on each sub area of tray box is implemented. Each part of them contains an item of food, so we detect the area using color channel segmentation and implements B component in LAB color space. After getting the main area of food, then two areas between segmented food image are compared before and after being consumed. The calculation of the predicted leftover portion is calculated based on original weight of food item. The result shows that tray box with black background with constant (cd) is the best to project leftover, in which reaches 2.37 of Root Mean Square Error (RMSE). It proves that the propose method is sufficient to handle the leftover prediction of food.

关键词：

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：