检索结果-内蒙古大学图书馆

arXiv 2020年

作者： Yi, Xinlei Zhang, Shengjun Yang, Tao Chai, Tianyou Johansson, Karl H. The Division of Decision and Control Systems School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm100 44 Sweden The Department of Electrical Engineering University of North Texas DentonTX76203 United States The State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang110819 China

The distributed nonconvex optimization problem of minimizing a global cost function formed by a sum of n local cost functions by using local information exchange is considered. This problem is an important component of many machine learning techniques with data parallelism, such as deep learning and federated learning. We propose a distributed primal–dual stochastic gradient descent (SGD) algorithm, suitable for arbitrarily connected communication networks and any smooth (possibly nonconvex) cost functions. We show that the proposed algorithm achieves the linear speedup convergence rate O(1/√nT) for general nonconvex cost functions and the linear speedup convergence rate O(1/(nT)) when the global cost function satisfies the Polyak–Lojasiewicz (P–L) condition, where T is the total number of iterations. We also show that the output of the proposed algorithm with constant parameters linearly converges to a neighborhood of a global optimum. We demonstrate through numerical experiments the efficiency of our algorithm in comparison with the baseline centralized SGD and recently proposed distributed SGD algorithms. Copyright © 2020, The Authors. All rights reserved.

关键词： Cost functions

来源：评论

学校读者我要写书评

暂无评论

Distributed delay model of the McKeithan’s network

引用

IFAC-PapersOnLine 2019年第7期52卷 33-38页

作者： György Lipták Katalin M. Hangos Process Control Research Group Systems and Control Laboratory Computer and Automation Research Institute Hungarian Academy of Sciences P.O. Box 63 H-1518 Budapest Hungary Department of Electrical Engineering and Information Systems University of Pannonia Veszprém Hungary

In this paper CRNs containing linear reaction chains with multiple joint complexes were considered in order to obtain an equivalent reduced order delayed CRN model with distributed time delays. For this purpose, our earlier method (Lipták and Hangos (2018)) for decomposing the chains of linear reactions with multiple joint complexes was used together with the "linear chain trick". An analytical expression for the kernel function of the distributed delay was also derived from the reaction rate coefficients of the linear reaction chains. Our approach was demonstrated using the example of the well known McKeithan’s network model of kinetic proofreading.

关键词： process control Delay Chemical Reaction Networks

来源：评论

学校读者我要写书评

暂无评论

The effect of thermal radiation on singularities in the dark universe

arXiv

引用

arXiv 2021年

作者： Brevik, Iver Timoshkin, A.V. Paul, Tanmoy Department of Energy and Process Engineering Norwegian University of Science and Technology TrondheimN-7491 Norway Tomsk State Pedagogical University Kievskaja Street 60 Tomsk634061 Russia International Laboratory of Theoretical Cosmology Tomsk State University of Control Systems and Radio Electronics Lenin Avenue 36 Tomsk634050 Russia Department of Physics Chandernagore College Hooghly712 136 India Department of Theoretical Physics Indian Association for the Cultivation of Science 2A & 2B Raja S.C. Mullick Road Kolkata700 032 India

Cosmological models with an inhomogeneous viscous dark fluid, coupled with dark matter in the Friedmann- Robertson-Walker (FRW) flat universe, are considered. The influence of thermal effects caused by Hawking radiation on the visible horizon is studied, in connection with the classified type I and type III singularities which are known to occur within a finite amount of time. Allowance of thermal effects implies that a transition to a type II singularity can take place, in a finite time. We take into account a bulk viscosity of the dark fluid, observing the equation of state in the case of radiation, and find that there is a qualitative change in the singular universe of type I: it may pass into a singularity of type III, or it may avoid the singularity at all. © 2021, CC BY.

关键词： Equations of state

来源：评论

学校读者我要写书评

暂无评论

Influence of remelting sequence on defect generation and high-temperature mechanical properties in laser powder bed fusion of IN718 alloys

引用

Additive Manufacturing 2025年

作者： Fuzhong Chu Shun Wu Haopeng Shen Hongyu Yan Yaping Wu Xianfa Xu Hao Zhang Aijun Huang Ruiping Zou Xinhua Wu Zongyan Zhou ARC Research Hub for Smart Process Design and Control Department of Chemical and Biological Engineering Monash University Clayton VIC 3800 Australia Monash Centre for Additive Manufacturing Monash University Notting Hill VIC 3168 Australia School of Iron and Steel Soochow University Suzhou 215021 China Jiangxi Provincial Key Laboratory for Simulation and Modelling of Particulate Systems Jiangxi University of Science and Technology Nanchang Campus Jiangxi 330013 China Faculty of Materials and Manufacturing Beijing University of Technology Beijing China

The laser multiple melting strategy is commonly employed in the laser powder bed fusion (LPBF) process to reduce porosity levels and optimize mechanical properties. However, the influence of the temporal sequences of energy input has received limited attention, despite their potential to control defect generation and microstructure evolution. Therefore, in this work, two specific remelting sequences were investigated, referred to here as the preheating strategy (a low-energy first scan followed by a high-energy second scan) and the remelting (a high-energy first scan followed by a low-energy second scan) strategy. The findings indicated that defect generation and surface roughness are highly sensitive to variations in the remelting sequences, demonstrating that samples subjected to the remelting strategy exhibit significantly lower porosity levels. The simulations revealed that the defects in the preheating strategy originate from insufficient melting between layers and rough top surfaces caused by inadequate melt pool flow. Additionally, the samples subjected to the remelting strategy exhibited superior high-temperature mechanical properties, with an ultimate tensile strength of 959.7 MPa, yield strength of 792 MPa, and outstanding elongation of 23.1% along the building direction after heat treatment. This enhancement was attributed to the increased geometrically necessary dislocation density induced by fine carbides measuring 0.9 μm. This study offers valuable insights into the laser multiple melting process, providing a foundation for future research aimed at optimizing mechanical properties in the LPBF process.

关键词： laser powder bed fusion remelting sequence defect generation simulation high-temperature mechanical property

来源：评论

学校读者我要写书评

暂无评论

The determination of deforestation rate in eastern Slovakia in the years 1998-2018 based on multispectral satellite images from missions Landsat 5 and 7 11

The determination of deforestation rate in eastern Slovakia ...

引用

11th International Scientific and Technical Conference on Geodesy, Cartography and Geoinformatics, GCG 2019

作者： Pukanská, Katarína Bartoš, Karol Gašinec, Juraj Kseňak, Ľubomír Frąckiewicz, Pawel Bieda, Agnieszka Institute of Geodesy Cartography and Geographical Information Systems Faculty of Mining Ecology Process Control and Geotechnologies Technical University of Košice Košice Slovakia Faculty of Environmental Geomatic and Energy Engineering Kielce University of Technology Kielce Poland Department of Geomatics Faculty of Mining Surveying and Environmental Engineering AGH University of Science and Technology Kraków Poland

ISBN: (纸本)9780367346515

By using the instruments and methods of remote sensing, it is possible to detect forest damage caused by pests or calamities, while reducing time demands and achieving nationwide assessment of the area. This paper deals with the determination of the extent of deforestation in the Rožňava district (Slovakia) on the principle of calculating the normalized difference vegetation index NDVI from multispectral images of Landsat 5 and Landsat 7 satellites. The data sets were prepared in 5-year epochs using the JavaScript programming language and satellite bands B3, B4, B5, and B7 so that the cloudiness is eliminated from images while displaying the forest cover during the vegetation period. The NDVI calculation was performed in the ESA SNAP software. The resulting data classification was subsequently realized by calculating the percentage decrease in QGIS 2.18 software. © 2020 Taylor & Francis Group, London.

关键词： Deforestation

来源：评论

学校读者我要写书评

暂无评论

Integration of multispectral and radar satellite images for flood range determination of historical flood in Slovakia 2010 11

Integration of multispectral and radar satellite images for ...

引用

11th International Scientific and Technical Conference on Geodesy, Cartography and Geoinformatics, GCG 2019

作者： Pukanská, Katarína Bartoš, Karol Hurčíková, Viera Kseňak, Ľubomír Gil, Marcin Bieda, Agnieszka Institute of Geodesy Cartography and Geographical Information Systems Faculty of Mining Ecology Process Control and Geotechnologies Technical University of Košice Košice Slovakia Faculty of Environmental Geomatic and Energy Engineering Kielce University of Technology Kielce Poland Department of Geomatics Faculty of Mining Surveying and Environmental Engineering AGH University of Science and Technology Kraków Poland

ISBN: (纸本)9780367346515

The objective of this work is to evaluate the extent of historic floods on rivers within Košice region in June 2010. Nowadays, massive floods are an annual reality, as the increasing number of natural disasters is a consequence of global climate changes. Their increasing frequency and severity cause immense damage to property, but also loss of human lives. For the purpose of mapping these floods, historical multispectral satellite images from Landsat 5 were used as the input data, together with radar image from Envisat, from the time of floods in 2010. The results of the floods were compared with the corresponding satellite data from the data with a normal situation. All used image and radar data are freely available to download and process. Given data sets were opened and processed in open-source software ESA-SNAP. The result of the study is the determination of the extent and quantification of historical floods in Eastern Slovakia in 2010. © 2020 Taylor & Francis Group, London.

关键词： Floods

来源：评论

学校读者我要写书评

暂无评论

Dead-Time Compensator for State-delay Stable systems

引用

IFAC-PapersOnLine 2018年第18期51卷 672-677页

作者： Albertos, P. García, P. Chen, Q. Luan, X. Department of Systems Engineering Control Instituto de Automática e Informática Industrial Universitat Politècnica deValència Spain Key Laboratory of Advance Process Control for Light Industries Institute of Automation Jiangnan University China

This paper deals with the control of simple process models with state-delays. A pre-compensator is used to cancel the delay. Due to the cancellation of some terms, the process as well as its undelayed part should be stable. Although the approach is general, in order to simplify the notation, second order systems are considered to describe the procedure. The proposed methodology is applied to compensate the delay in a recycled reactor as well as to control a pure state-delayed academic example. © 2018

关键词： process control Delay control systems Recycling control design Dead time compensator Dead time compensation Pre compensator Second order systemss Stable systems State delay Time delay systems

来源：评论

学校读者我要写书评

暂无评论

Corrigendum to "Current challenges of hydrothermal treated wastewater (HTWW) for environmental applications and their perspectives: A review" [Environ. Res. 212 Part D (2022) 113532]

引用

Environmental research 2024年第PT 3期252卷 119005页

作者： Muhammad Usman Zhijian Shi Nalok Dutta Muhammad Awais Ashraf Bushra Ishfaq Mohamed Gamal El-Din Department of Civil and Environmental Engineering University of Alberta Edmonton AB T6G 2W2 Canada Bioproducts Sciences and Engineering Laboratory (BSEL) Washington State University Tri-Cities Richland WA 99354 United States Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3) Department of Environmental Science and Engineering Fudan University Shanghai 200433 China Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes Shanghai 200438 China. Electronic address: musman4@ualberta.ca. Shanghai Technical Service Platform for Pollution Control and Resource Utilization of Organic Wastes Shanghai 200438 China. Bioproducts Sciences and Engineering Laboratory (BSEL) Washington State University Tri-Cities Richland WA 99354 United States. State Key Laboratory of Multiphase Complex Systems CAS Key Laboratory of Green Process and Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 China. Food Technology Section Post-harvest Research Center Ayub Agricultural Research Institute Faisalabad Pakistan. Department of Civil and Environmental Engineering University of Alberta Edmonton AB T6G 2W2 Canada. Electronic address: mgamalel-din@ualberta.ca.

来源：评论

学校读者我要写书评

暂无评论

Robust Stabilization of T-S Fuzzy Stochastic Descriptor systems via Integral Sliding Modes

引用

IEEE TRANSACTIONS ON CYBERNETICS 2018年第9期48卷 2736-2749页

作者： Li, Jinghao Zhang, Qingling Yan, Xing-Gang Spurgeon, Sarah K. Institute of Systems Science State Key Laboratory of Synthetical Automation for Process Industries Northeastern University Shenyang China Instrumentation Control and Embedded Systems Research Group School of Engineering and Digital Arts University of Kent Canterbury U.K. Department of Electronic and Electrical Engineering University College London London U.K.

This paper addresses the robust stabilization problem for T-S fuzzy stochastic descriptor systems using an integral sliding mode control paradigm. A classical integral sliding mode control scheme and a nonparallel distributed compensation (Non-PDC) integral sliding mode control scheme are presented. It is shown that two restrictive assumptions previously adopted developing sliding mode controllers for Takagi-Sugeno (T-S) fuzzy stochastic systems are not required with the proposed framework. A unified framework for sliding mode control of T-S fuzzy systems is formulated. The proposed Non-PDC integral sliding mode control scheme encompasses existing schemes when the previously imposed assumptions hold. Stability of the sliding motion is analyzed and the sliding mode controller is parameterized in terms of the solutions of a set of linear matrix inequalities which facilitates design. The methodology is applied to an inverted pendulum model to validate the effectiveness of the results presented.

关键词： Integral sliding mode control inverted pendulum nonparallel distributed compensation (Non-PDC) robust stabilization Takagi-Sugeno (T-S) fuzzy stochastic descriptor systems

来源：评论

学校读者我要写书评

暂无评论

Synchronization of Chaotic systems: a survey study

Synchronization of Chaotic Systems: a survey study

引用

Signal, control and Communication (SCC), International Conference on

作者： Noussaiba Griba Faiçal Hamidi Kamel Menighed Boumedyen Boussaid Mohamed Naceur Abdelkrim Lobaratory of Modelling Analysis and Control of Systems (MACS) University of Gabes Gabes Tunisia Petrochemical and Process Engineering Department University August 20 1955-Skikda Skikda Algeria

ISBN: (数字)9781728135960

ISBN: (纸本)9781728135977

This paper gives a survey study of the synchronization of nonlinear systems with chaotic behavior. The chaotic systems studied are Lorenz and Rössler systems. The principal configuration of the synchronization techniques belong to the "Master-Slave" configuration. The techniques widely used to achieve synchronization are "linear active control" and "Nonlinear active control". Numerical simulations are provided to show the effectiveness of these methods.

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：