检索结果-内蒙古大学图书馆

Magnetoelastic coupling driven magnon gap in a honeycomb antiferromagnet

Physical Review B 2024年第10期110卷 104419页

作者： Jeongheon Choe Andrey Baydin Gaihua Ye Bowen Ma Cynthia Nnokwe Martin Rodriguez-Vega David Lujan Swati Chaudhary Fuyang Tay Jiaming He Hiroyuki Nojiri Jianshi Zhou Gregory A. Fiete Junichiro Kono Rui He Xiaoqin Li Department of Physics Center of Complex Quantum Systems Center for Dynamics and Control of Materials Department of Electrical and Computer Engineering Smalley–Curl Institute Department of Physics Applied Physics Graduate Program Smalley–Curl Institute Department of Mechanical Engineering Institute for Materials Research Department of Physics and Astronomy Department of Materials Science and NanoEngineering

Cobalt titanate, CoTiO3, is a honeycomb antiferromagnet recently confirmed experimentally to host Dirac magnons, topological spin-orbit excitons, and chiral phonons. Here, we investigate a magnon gap at the zone center which calls for a refined spin Hamiltonian. We propose a microscopic model for the magnon gap and attribute it to a lattice-distortion (phonon)-induced higher-order spin interaction. Strong magnetoelastic coupling in CoTiO3 is also evident in Raman spectra, in which the magnetic order exerts a stronger influence on phonons corresponding to in-plane ionic motions than those with out-of-plane motions. We further examine the evolution of the zone-center magnons in a high magnetic field up to 18.5 T via THz absorption spectroscopy measurements. Based on this field dependence, we propose a spin Hamiltonian that not only agrees with magnon dispersion measured by inelastic neutron scattering but also includes fewer exchange constants and a realistic anisotropy term. Our work highlights the broad implications of magnetoelastic coupling in the study of topologically protected bosonic excitations.

关键词： Magnetism Magnons Topological materials Raman spectroscopy Terahertz spectroscopy

来源：评论

学校读者我要写书评

暂无评论

Sensitivity Analysis on Green Hydrogen as Energy Storage: A Techno-Economic Case study

Sensitivity Analysis on Green Hydrogen as Energy Storage: A ...

引用

IEEE General Meeting Power& Energy Society

作者： Rahul R Urs Assia Chadly Ahmad Mayyas Ameena Al Sumaiti Department of Industrial Systems and Engineering Khalifa university Abu Dhabi UAE Department of Electrical & Computer Science Engineering Khalifa university Abu Dhabi UAE

Production of green Hydrogen is increasingly helping the world achieve its energy transition goals. Compared to conventional methods, producing Hydrogen using green energy produces fewer carbon emissions. Furthermore, green Hydrogen can be produced from several renewable sources depending on the region’s potential. Photovoltaic systems are considered in this study to estimate green hydrogen production in the United Arab Emirates. The impact of electrolyzer and hydrogen tank capital expenses on green Hydrogen production has been extensively researched in the literature. However, the impact of the varying capital cost is often overlooked. In this work, we analyze the sensitivity of renewable systems’ costs to changes in the costs of producing Hydrogen, and employing it as energy storage.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Market Conditions and their Effect on Market Clearing Price Forecasting 2

Market Conditions and their Effect on Market Clearing Price ...

引用

2nd International Conference on Energy Transition in the Mediterranean Area, SyNERGY MED 2022

作者： Loizidis, Stylianos Konstantinidis, Georgios Theocharidis, Spyros Kyprianou, Andreas Georghiou, George E. University of Cyprus Pv Technology Laboratory Foss Research Centre for Sustainable Energy Department of Electrical and Computer Engineering Nicosia Cyprus University of Cyprus Pv Technology Laboratory Foss Research Centre for Sustainable Energy Department of Mechanical and Manufacturing Engineering Nicosia Cyprus

ISBN: (数字)9781665461078

ISBN: (纸本)9781665461078

High volatility in deregulated electricity markets is that characteristic that exposes its participants to higher risks. Volatility is due to many, and most of the times unpredictable, factors, ranging from fuel prices, production from renewable energy sources, electricity demand to Covid-19 and energy crisis. This article describes the initial stages of the work that combines signalling with market conditions in order to analyse the factors affecting the clearing prices of the day ahead market in view of enhancing the forecasting of these prices. The proposed forecasting methodology is based on the extreme learning machine (ELM) and it is tested on the German and Finnish markets. © 2022 IEEE.

关键词： Forecasting

来源：评论

学校读者我要写书评

暂无评论

Network-Agnostic Voltage-to-Power Sensitivities of a Real-Time Reduced Active Distribution Network

Network-Agnostic Voltage-to-Power Sensitivities of a Real-Ti...

引用

IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia)

作者： Manorath Prasad Zakir Hussain Rather Reza Razzaghi Suryanarayana Doolla Department of Energy Science and Engineering Indian Institute of Technology Bombay Mumbai India Department of Electrical and Computer Systems Engineering Monash University Melbourne Australia

The advent of distribution-level phasor measurement units (D-PMUs) has enhanced the observability of active distribution networks (ADNs) and improved their energy management and control. Recently, various ADN control strategies that require detailed network parameter information have been proposed based on the voltage-to-power sensitivities of the ADN nodes. This paper proposes a new realistic approach to determining nodal voltage-to-power sensitivities of a synchrophasor measurement-based reduced ADN model. The real-time synchrophasor data dynamically updates the parameters of the reduced equivalent model to follow the time-varying operating conditions of the ADN accurately. The voltage-to-power sensitivities of the retained observable nodes are derived from the power flow Jacobian matrix using reduced equivalent model parameters. Thus, the proposed approach is agnostic about detailed line impedance data of the complex ADN. Further, the computational complexity is significantly decreased with the reduced number of nodes in the equivalent ADN model. The proposed approach has been tested on modified IEEE-33 bus benchmark system with high penetration of photovoltaic inverters using a DIgSILENT PowerFactory MATLAB co-simulation platform.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Incremental Volt/Var Control for Distribution Networks via Chance-Constrained Optimization

arXiv

引用

arXiv 2024年

作者： Colot, Antonin Perotti, Elisabetta Glavic, Mevludin Dall’Anese, Emiliano Montefiore Institute University of Liège Belgium Department of ECEE University of Colorado Boulder United States Department of Electrical and Computer Engineering The Division of Systems Engineering Boston University United States

This paper considers an incremental Volt/Var control scheme for distribution systems with high integration of inverter-interfaced distributed generation (such as photovoltaic systems). The incremental Volt/Var controller is implemented with the objective of minimizing reactive power usage while maintaining voltages within safe limits sufficiently often. To this end, the parameters of the incremental Volt/Var controller are obtained by solving a chance-constrained optimization problem, where constraints are designed to ensure that voltage violations do not occur more often than a pre-specified probability. This approach leads to cost savings in a controlled, predictable way, while still avoiding significant over- or under-voltage issues. The proposed chance-constrained problem is solved using a successive convex approximation method. Once the gains are broadcast to the inverters, no additional communication is required since the controller is implemented locally at the inverters. The proposed method is successfully tested on a low-voltage single-phase 42-nodes network and on the three-phase unbalanced IEEE 123-node test system. © 2024, CC BY.

关键词： Constrained optimization

来源：评论

学校读者我要写书评

暂无评论

Control Design for Position Synchronization in Central Converter Multi-Machine Actuators

Control Design for Position Synchronization in Central Conve...

引用

electrical, computer, Communications and Mechatronics engineering (ICECCME), International Conference on

作者： Cláudio de Andrade Lima James Cale Electrical and Computer Engineering Department Colorado State University Fort Collins USA Systems Engineering Department Colorado State University Fort Collins USA

To support further electrification of the aircraft industry, replacements of mechanical with electrical drives for various applications are being considered. Previous research by the authors proposed a drive architecture and control strategy for electromechanical thrust-reverse actuation in aircraft using parallel induction machines in a central-converter multiple-machine architecture, with rotor position synchronization achieved with variable stator resistance circuits controlled with proportional-integral feedback. This paper describes an improved control design employing the H-infinity method. Model linearization and weight function selection for the modified plant in the optimal control synthesis problem are described. Primary findings are that control performance using the proposed approach is improved in terms of maximum and normed position errors and also convergence time compared to the previous design.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Perfect Subset Privacy in Polynomial Computation

Perfect Subset Privacy in Polynomial Computation

引用

IEEE International Symposium on Information Theory

作者： Zirui Deng Vinayak Ramkumar Netanel Raviv Department of Computer Science and Engineering Washington University in St. Louis St. Louis MO USA Department of Electrical Engineering-Systems Tel Aviv University Tel Aviv Israel

ISBN: (数字)9798350382846

ISBN: (纸本)9798350382853

Delegating large-scale computations to service providers is a common practice which raises privacy concerns. This paper studies information-theoretic privacy-preserving del-egation of data to a service provider, who may further delegate the computation to auxiliary worker nodes, in order to compute a polynomial over that data at a later point in time. We study techniques which are compatible with robust management of distributed computation systems, an area known as coded computing. Privacy in coded computing, however, has tradition-ally addressed the problem of colluding workers, and assumed that the server that administrates the computation is trusted. This viewpoint of privacy does not accurately reflect real-world privacy concerns, since normally, the service provider as a whole (i.e., the administrator and the worker nodes) form one cohesive entity which itself poses a privacy risk. This paper aims to shift the focus of privacy in coded computing to safeguarding the privacy of the user against the service provider as a whole, instead of merely against colluding workers inside the service provider. To this end, we leverage the recently defined notion of perfect subset privacy, which guarantees zero information leakage from all subsets of the data up to a certain size. Using known techniques from Reed-Muller decoding, we provide a scheme which enables polynomial computation with perfect subset privacy in straggler-free systems. Furthermore, by studying information super-sets in Reed-Muller codes, which may be of independent interest, we extend the previous scheme to tolerate straggling worker nodes inside the service provider.

关键词： Privacy Data privacy Codes Reed-Muller codes Information leakage Polynomials Decoding

来源：评论

学校读者我要写书评

暂无评论

Use and usability of software verification methods to detect behaviour interference when teaching an assistive home companion robot: A proof-of-concept study

引用

Paladyn 2021年第1期12卷 402-422页

作者： Koay, Kheng Lee Webster, Matt Dixon, Clare Gainer, Paul Syrdal, Dag Fisher, Michael Dautenhahn, Kerstin Department of Computer Science School of Physics Engineering and Computer Science University of Hertfordshire College Lane Hertfordshire HatfieldAL10 9AB United Kingdom School of Computer Science and Mathematics Liverpool John Moores University LiverpoolL2 2QP United Kingdom Department of Computer Science University of Manchester ManchesterM13 9PL United Kingdom Department of Computer Science University of Liverpool Liverpool United Kingdom Department of Computer Science School of Physics Engineering and Computer Science University of Hertfordshire College Lane Hertfordshire HatfieldAL10 9AB United Kingdom Departments of Electrical and Computer Engineering and Systems Design Engineering University of Waterloo ON Canada

When studying the use of assistive robots in home environments, and especially how such robots can be personalised to meet the needs of the resident, key concerns are issues related to behaviour verification, behaviour interference and safety. Here, personalisation refers to the teaching of new robot behaviours by both technical and non-technical end users. In this article, we consider the issue of behaviour interference caused by situations where newly taught robot behaviours may affect or be affected by existing behaviours and thus, those behaviours will not or might not ever be executed. We focus in particular on how such situations can be detected and presented to the user. We describe the human-robot behaviour teaching system that we developed as well as the formal behaviour checking methods used. The online use of behaviour checking is demonstrated, based on static analysis of behaviours during the operation of the robot, and evaluated in a user study. We conducted a proof-of-concept human-robot interaction study with an autonomous, multi-purpose robot operating within a smart home environment. Twenty participants individually taught the robot behaviours according to instructions they were given, some of which caused interference with other behaviours. A mechanism for detecting behaviour interference provided feedback to participants and suggestions on how to resolve those conflicts. We assessed the participants' views on detected interference as reported by the behaviour teaching system. Results indicate that interference warnings given to participants during teaching provoked an understanding of the issue. We did not find a significant influence of participants' technical background. These results highlight a promising path towards verification and validation of assistive home companion robots that allow end-user personalisation. © 2021 Kheng Lee Koay et al., published by De Gruyter.

关键词： Human robot interaction

来源：评论

学校读者我要写书评

暂无评论

3D Drone Path Planning Algorithms with Collision Avoidance: Collision Resolution vs. Prevention

3D Drone Path Planning Algorithms with Collision Avoidance: ...

引用

IEEE World Forum on Internet of Things (WF-IoT)

作者： Rutuja Shivgan Jorge Medina Ziqian Dong Roberto Rojas–Cessa Department of Electrical and Computer Engineering New York Institute of Technology New York NY Department of Electrical and Computer Engineering Networking Research Laboratory Helen and John C. Hartmann New Jersey Institute of Technology Newark NJ

ISBN: (数字)9798350311617

ISBN: (纸本)9798350311624

Because of their limited flight range, multiple drones are often deployed simultaneously to perform complex tasks. The flight path is planned for each drone to follow to complete the job before task execution. However, multi-drone path planning places drones at risk of in-flight collisions. To overcome this problem, we model the multi-drone path planning problem as a multi-vehicle routing problem that maximizes job coverage subject to collision-free paths. We propose three 3D collision-free path planning algorithms, namely, XTRACT, 3DETACH, and ASCEND. XTRACT and 3DETACH provide collision-free paths by setting partial paths at different altitudes while ASCEND prevents intersecting paths at the planning phase by selecting different altitudes. We limit the search processes to two altitudes to demonstrate sufficiency with the lowest height complexity. Through exhaustive evaluations, we compare the performance of the proposed schemes and show the trade-offs between resolving and preventing collisions from path planning. We identify the best-performing strategy by using a profit model to evaluate the plethora of applicable performance metrics.

关键词： Space vehicles Solid modeling Three-dimensional displays Vehicle routing Path planning Orbits Planning

来源：评论

学校读者我要写书评

暂无评论

A Deep Features Based Approach Using Modified ResNet50 and Gradient Boosting for Visual Sentiments Classification

arXiv

引用

arXiv 2024年

作者： Arslan, Muhammad Mubeen, Muhammad Akram, Arslan Abbasi, Saadullah Farooq Ali, Muhammad Salman Tariq, Muhammad Usman Department of Computer Science Loyola University Chicago Chicago United States Department of Computer Science University Of the People CA United States Facultty of Computer Science and Information Technology The Superior University Lahore Lahore Pakistan Department of Electronic Electrical and Systems Engineering University of Birmingham Birmingham United Kingdom

The versatile nature of Visual Sentiment Analysis (VSA) is one reason for its rising profile. It isn't easy to efficiently manage social media data with visual information since previous research has concentrated on Sentiment Analysis (SA) of single modalities, like textual. In addition, most visual sentiment studies need to adequately classify sentiment because they are mainly focused on simply merging modal attributes without investigating their intricate relationships. This prompted the suggestion of developing a fusion of deep learning and machine learning algorithms. In this research, a deep feature-based method for multiclass classification has been used to extract deep features from modified ResNet50. Furthermore, gradient boosting algorithm has been used to classify photos containing emotional content. The approach is thoroughly evaluated on two benchmarked datasets, CrowdFlower and GAPED. Finally, cutting-edge deep learning and machine learning models were used to compare the proposed strategy. When compared to state-of-the-art approaches, the proposed method demonstrates exceptional performance on the datasets presented. © 2024, CC BY.

关键词： Contrastive Learning

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：