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Novel Static Security and Stability Control of Power Systems Based on Artificial Emotional Lazy Q-Learning

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Energy Engineering 2024年第6期121卷 1713-1737页

作者： Tao Bao Xiyuan Ma Zhuohuan Li Duotong Yang Pengyu Wang Changcheng Zhou digital Grid Research institute Southern Power GridGuangzhou510000China

The stability problem of power grids has become increasingly serious in recent years as the size of novel power systems *** order to improve and ensure the stable operation of the novel power system,this study proposes an artificial emotional lazy Q-learning method,which combines artificial emotion,lazy learning,and reinforcement learning for static security and stability analysis of power ***,this study compares the analysis results of the proposed method with those of the small disturbance method for a stand-alone power system and verifies that the proposed lazy Q-learning method is able to effectively screen useful data for learning,and improve the static security stability of the new type of power system more effectively than the traditional proportional-integral-differential control and Q-learning methods.

关键词： Artificial sentiment static secure stable analysis Q-learning lazy learning data filtering

SPARSE RECOVERY BASED ON THE GENERALIZED ERROR FUNCTION

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Journal of Computational Mathematics 2024年第3期42卷 679-704页

作者： Zhiyong Zhou Department of Statistics and Data Science and Institute of Digital FinanceHangzhou City UniversityHangzhou 310015China

In this paper,we offer a new sparse recovery strategy based on the generalized error *** introduced penalty function involves both the shape and the scale parameters,making it extremely *** both constrained and unconstrained models,the theoretical analysis results in terms of the null space property,the spherical section property and the restricted invertibility factor are *** practical algorithms via both the iteratively reweighted■_(1)and the difference of convex functions algorithms are *** experiments are carried out to demonstrate the benefits of the suggested approach in a variety of *** practical application in magnetic resonance imaging(MRI)reconstruction is also investigated.

关键词： Sparse recovery Generalized error function Nonconvex regularization Itera-tive reweighted Li Difference of convex functions algorithms

Performance Enhancement of Single-Phase Immersion Liquid-Cooled Data Center Servers

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Journal of Thermal Science 2024年第5期33卷 1757-1772页

作者： GE Junlei XIA Feifan ZHANG Chengbin HUANG Yongping School of Energy and Environment Southeast UniversityNanjing 210096China Wuhan digital Engineering Research institute Wuhan 430205China

As the promising cooling method for the next generation of data centers,the internal heat transport mechanism and enhancement mechanism of single-phase immersion liquid-cooled(SPILC)systems are not yet well *** address this,a steady-state three-dimensional numerical model is constructed herein to analyze flow and thermal transport capacities in servers using SPILC and traditional air-cooling ***,this paper emphasizes the influence of component positioning,and underscores the benefits of optimizing coolant flow distribution using *** results indicate that the SPILC system outperforms the traditional air-cooling approach at the same inlet Reynolds number(Re).When Re=10000,the SPILC method reduces the maximum temperature by up to 70.13%,increases the average convective heat transfer coefficient by287.5%,and provides better overall thermal uniformity in data center ***,placing devices downstream of high-power components creates"thermal barriers"and degrades thermal transport for upstream devices due to increased flow *** spacing between high-power devices can lead to the formation of bypass channels,further deteriorating heat ***,the addition of baffles in the inlet section of SPILC systems effectively enhances heat dissipation *** maximize the heat dissipation capacity,minimizing bypass channels and optimizing the flow distribution of coolants are crucial.

关键词： single-phase immersion liquid-cooled performance enhancement data center

A cross-sectional analysis of the effectiveness of a nutritional support programme for people with tuberculosis in Southern Madagascar using secondary data from a non-governmental organisation

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Infectious Diseases of Poverty 2024年第1期13卷 101-102页

作者： Mara Anna Franke Julius Valentin Emmrich Fierenantsoa Ranjaharinony Onja GbrilleRavololohanitra Harizaka Emmanuel Andriamasy Samuel Knauss Nadine Muller Global digital health Lab at Charité Center for Global health Charité – Universitätsmedizin Berlin Berlin Germany London School of Hygiene and Tropical Medicine London UK Ärzte Für Madagaskar E.V. Leipzig Germany Heidelberg institute of Global health Heidelberg University Heidelberg Germany Berlin institute of health at Charité - Universitätsmedizin Berlin Berlin Germany Doctors for Madagascar Antananarivo Madagascar Speciality Network: Infectious Diseases and Respiratory Medicine Charité - Universitätsmedizin Berlin Berlin Germany

Background There is a strong,bi-directional link between tuberculosis(TB)and undernutrition:TB often causes undernutrition,and undernourished people are more likely to contract TB and experience worse ***,several TB nutritional support programmes exist;however,evidence on their effectiveness is limited and *** study evaluates the effect of a nutritional support programme implemented for people with TB in the Atsimo-Andrefana region,Madagascar in *** this programme,undernourished people with TB[with a body mass index(BMI)of<18.5 kg/m]receive 0.6 L of vegetable oil and 6.0 kg of a soy-wheat blend per month throughout their TB *** We analysed secondary non-governmental organisation data collected between January and Novem-ber 2022 in the Atsimo-Andrefana region,Southern Madagascar,including information on an individual's medical conditions(e.g.,type of TB,treatment outcomes)and nutritional status measured prior to,during,and after comple-tion of treatment(e.g.,height,weight,mid-upper arm circumference).We conducted descriptive analyses of patient baseline characteristics and outcomes to assess the impact of the provided nutritional support on the BMI of people With *** A total of 1310 people with TB were included in the study[9.9%(130)children under the age of 5,32.1%(420)children between 5 and 18 years,58.0%(760)adults].55.4% of children under 5,28.1% of children between ages 5 and 18,and 81.3%of adults were undernourished at treatment initiation.42.3%(55/130)of children under 5 experi-enced severe acute malnutrition at treatment *** the average BMl of adults with TB receiving food support increased over time,from 17.1 kg/m^(2)(interquartile range:15.8-18.3,range:10.3-22.5)to 17.9 kg/m^(2)(interquartile range:16.6-19.1,range:11.9-24.1),most adults remained undernourished even after completing TB *** The current TB nutritional support programme falls short of sufficiently increasing the BM

关键词： Tuberculosis Sub-Saharan Africa Undernutrition Nutritional support

digital Twin Modeling Enabled Machine Tool Intelligence:A Review

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 29-54页

作者： Lei Zhang Jianhua Liu Cunbo Zhuang School of Mechanical Engineering Tianjin University of CommerceTianjin 300134China Laboratory of digital Manufacturing School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 10081China

Machine tools,often referred to as the“mother machines”of the manufacturing industry,are crucial in developing smart manufacturing and are increasingly becoming more *** twin technology can promote machine tool intelligence and has attracted considerable research ***,there is a lack of clear and systematic analyses on how the digital twin technology enables machine tool ***,digital twin modeling was identified as an enabling technology for machine tool intelligence based on a comparative study of the characteristics of machine tool intelligence and digital *** review then delves into state-of-the-art digital twin modelingenabled machine tool intelligence,examining it from the aspects of data-based modeling and mechanism-data dual-driven ***,it highlights three bottleneck issues facing the *** these problems,the architecture of a digital twin machine tool(DTMT)is proposed,and three key technologies are expounded in detail:Data perception and fusion technology,mechanism-data-knowledge hybrid-driven digital twin modeling and virtual-real synchronization technology,and dynamic optimization and collaborative control technology for multilevel ***,future research directions for the DTMT are *** work can provide a foundation basis for the research and implementation of digital-twin modeling-enabled machine tool intelligence,making it significant for developing intelligent machine tools.

关键词： Machine tool digital twin Smart manufacturing Synchronization

Temporal and spatial evolution of global major grain trade patterns

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Journal of Integrative Agriculture 2024年第3期23卷 1075-1086页

作者： Ziqi Yin Jiaxuan Hu Jing Zhang Xiangyang Zhou Lingling Li Jianzhai Wu Agricultural Information institute Chinese Academy of Agricultural SciencesBeijing 100081China institute of Scientific and Technical Information of China Beijing 100038China Zibo Agricultural Science Research institute Zibo 255000China Zibo institute for digital Agriculture and Rural Research Zibo 255000China

The complex and volatile international landscape has significantly impacted global grain supply security. This study uses a complex network analysis model to examine the evolution and trends of the global major grain trade from 1990 to 2020, focusing on network topology, centrality ranking, and community structure. There are three major findings. First, the global major grain trade network has expanded in scale, with a growing emphasis on diversification and balance. During the study period, the United States, Canada, China, and Brazil were the core nodes of the network. Grain-exporting countries were mainly situated in Asia, the Americas, and Europe, and importing countries in Asia, Africa, and Europe. Second, a significant increase in the number of high centrality countries with high export capacity occurred, benefiting from natural advantages such as fertile land and favorable climates. Third, the main global grain trade network is divided into four communities, with the Americas-Europe community being the largest and most widespread. The formation of the community pattern was influenced by geographic proximity, driven by the core exporting countries. Therefore, the world needs to enhance the existing trade model, promote the multi-polarization of the grain trade network, and establish a global vision for the future community. Countries and regions should participate actively in global grain trade security governance and institutional reform, expand trade links with other countries, and optimize import and export policies to reduce trade risks.

关键词： grain trade pattern evolution complex network

Fabricating functionally graded Fe-Cr-Co permanent magnetic alloys via laser powder bed fusion

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Journal of Iron and Steel Research International 2024年第3期31卷 729-737页

作者： Ya-zhou He Ya-qing Hou Peng Shen Hao Zhang Dong Zhou Hang Su Central Iron and Steel Research institute Co. Ltd.Beijing 100081China Material digital R&D Center China Iron and Steel Research Institute Group Co.Ltd.Beijing 100081China

Laser powder bed fusion(LPBF)in-situ alloying technology offers the possibility to construct gradient materials with varied structures and *** graded Fe-Cr-Co permanent magnetic alloys were fabricated by LPBF and in-situ alloying mixed powders of Fe,Cr,and Co *** effects of different Fe,Cr and Co contents on the microstructure,magnetic properties and hardness of Fe-Cr-Co alloys prepared by LPBF were *** as-built Fe-Cr-Co alloys present a single body-centered-cubic phase and have a homogeneous distribution of *** mechanical properties and magnetic properties of the compositionally graded sample show a gradient *** the increase in Cr content,the Vickers hardness of the sample increases,and the saturation magnetization of the sample *** optimal magnetic properties in an isotropic state are given as coercivity HcB=21.65 kA/m,remanence Br=0.70 T and energy product(BH)_(max)=5.35 kJ/m^(3),which are comparable to or higher than the reported magnetic properties in an isotropic state prepared by traditional powder *** in-situ alloying technology has the potential to further explore Fe-Cr-Co magnetic materials,such as those consisting of multiple or more constituent elements,and to maximize the compositional flexibility of magnetic materials.

关键词： Fe-Cr-Co alloy Laser powder bed fusion In-situ alloying Functional material Magnetic property

A Framework Based on the DAO and NFT in Blockchain for Electronic Document Sharing

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2373-2395页

作者： Lin Chen Jiaming Zhu Yuting Xu Huanqin Zheng Shen Su Cyberspace institute of Advanced Technology Guangzhou UniversityGuangzhou510006China Engineering Research Center of lntegration and Application of digital Learning Technology Ministry of EducationBeijing100816China

In the information age,electronic documents(e-documents)have become a popular alternative to paper documents due to their lower costs,higher dissemination rates,and ease of knowledge ***,digital copyright infringements occur frequently due to the ease of copying,which not only infringes on the rights of creators but also weakens their creative ***,it is crucial to establish an e-document sharing system that enforces copyright ***,the existing centralized system has outstanding vulnerabilities,and the plagiarism detection algorithm used cannot fully detect the context,semantics,style,and other factors of the *** watermark technology is only used as a means of infringement *** paper proposes a decentralized framework for e-document sharing based on decentralized autonomous organization(DAO)and non-fungible token(NFT)in *** use of blockchain as a distributed credit base resolves the vulnerabilities inherent in traditional centralized *** e-document evaluation and plagiarism detection mechanisms based on the DAO model effectively address challenges in comprehensive text information checks,thereby promoting the enhancement of e-document *** mechanism for protecting and circulating e-document copyrights using NFT technology ensures effective safeguarding of users’e-document copyrights and facilitates e-document ***,recognizing the security issues within the DAO governance mechanism,we introduce an innovative optimization *** experimentation,we validate the enhanced security of the optimized governance mechanism,reducing manipulation risks by up to 51%.Additionally,by utilizing evolutionary game analysis to deduce the equilibrium strategies of the framework,we discovered that adjusting the reward and penalty parameters of the incentive mechanism motivates creators to generate superior quality and unique e-documents,while evaluators are more likely to engage in

关键词： Electronic document sharing blockchain DAO NFT evolutionary game

Method of extracting disturbed position in φ-OTDR based on signal relevance evaluation

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Optoelectronics Letters 2024年第9期20卷 513-517页

作者： LI Chengzhi YANG Yang LIU Lijun GAO Fei DU Xuan LIANG Hu Kunlun digital Technology Co. Ltd.Beijing 102206China Tianjin Navigation Instruments Research institute Tianjin 300131China

A theoretical analysis was conducted on the intrinsic bond between multi-point responses caused by the same single vibration in phase sensitive optical time-domain reflectometer(OTDR). Temporal similarity of signals collected from adjacent sample locations were investigated. Referring to correlation coefficient as well as the relative energy level, a method of extracting disturbed position in φ-OTDR based on signal relevance evaluation is proposed to perform fast screening of massive φ-OTDR raw data to pinpoint those signals with significance.

关键词： OTDR signal disturbed