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Distributed Secondary Control Based on Dynamic Diffusion Algorithm for Current Sharing and Average Voltage Regulation in DC Microgrids

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journal of Modern Power Systems and Clean Energy 2024年第2期12卷 597-607页

作者： Dawei Liao Fei Gao Daniel j.Rogers Wentao Huang dong Liu Houjun Tang Department of Electrical Engineering Shanghai Jiao Tong UniversityShanghaiChina Department of Engineering Science University of OxfordOxford OX12JDU.K. IEEE

This paper introduces a distributed secondary control scheme for achieving current sharing and average voltage regulation objectives in a DC *** proposed scheme employs a dynamic diffusion algorithm(DDA)instead of the consensus algorithm to enable distributed communication among *** help understand DDA,the relation of DDA and other diffusion algorithms is discussed in detail and its superiority is shown by comparison with diffusion and consensus ***,considering the discrete nature and different sampling time of the digital controller and communication network,a z-domain model of the entire DC microgrid is *** influence of communication and secondary control parameters on the system stability is *** on the established model,the tolerable communication rates are ***-time simulations conducted on the OPAL-RT platform validate the effectiveness of the proposed scheme,showcasing its advantages in terms of convergence speed and stability.

关键词： Cooperative control DC microgrid diffusion algorithm discrete-time modeling distributed secondary control

Coordinate-wise monotonic transformations enable privacy-preserving age estimation with 3D face point cloud

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Science China(Life Sciences) 2024年第7期67卷 1489-1501页

作者： Xinyu Yang Runhan Li Xindi Yang Yong Zhou Yi Liu jing-dong j.Han School of Life Sciences Peking UniversityBeijing 100871China Peking-Tsinghua Center for Life Sciences Academy for Advanced Interdisciplinary StudiesCenter for Quantitative Biology(CQB)Peking UniversityBeijing 100871China Beijing Key Lab of Traffic Data Analysis and Mining School of Computer and Information TechnologyBeijing Jiaotong UniversityBeijing 100044China Clinical Research Institute Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200025China

The human face is a valuable biomarker of aging,but the collection and use of its image raise significant privacy *** we present an approach for facial data masking that preserves age-related features using coordinate-wise monotonic *** first develop a deep learning model that estimates age directly from non-registered face point clouds with high accuracy and *** show that the model learns a highly indistinguishable mapping using faces treated with coordinate-wise monotonic transformations,indicating that the relative positioning of facial information is a low-level biomarker of facial *** visual perception tests and computational3D face verification experiments,we demonstrate that transformed faces are significantly more difficult to perceive for human but not for machines,except when only the face shape information is *** study leads to a facial data protection guideline that has the potential to broaden public access to face datasets with minimized privacy risks.

关键词： face point cloud age estimation face verification privacy coordinate-wise monotonic transformation

Local search yields a PTAS for fixed-dimensional k-means problem with penalties

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journal of the Operations Research Society of China 2024年第2期12卷 351-362页

作者： Fan Yuan Da-Chuan Xu dong-Lei Du dong-Mei Zhang Beijing Institute for Scientific and Engineering Computing Beijing University of TechnologyBeijing 100124China Faculty of Management University of New BrunswickFrederictonNB E3B 9Y2Canada School of Computer Science and Technology Shandong Jianzhu UniversityJinan 250101ShandongChina

We study a problem called the k-means problem with penalties(k-MPWP),which is a natural generalization of the typical k-means *** this problem,we have a set D of client points in R^(d),a set F of possible centers in R^(d),and a penalty cost Pj>O for each point j∈*** are also given an integer k which is the size of the center point *** want to find a center point set S■F with size k,choose a penalized subset of clients P■D,and assign every client in D\P to its open *** goal is to minimize the sum of the squared distances between every point in D\P to its assigned centre point and the sum of the penalty costs for all clients in *** using the multi-swap local search technique and under the fixed-dimensional Euclidean space setting,we present a polynomial-time approximation scheme(PTAS)for the k-MPWP.

关键词： Approximation algorithm k-means Local search Penalty

Numerical Investigations on the Resonance Errors of Multiscale Discontinuous Galerkin Methods for One-Dimensional Stationary Schrödinger Equation

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Communications on Applied Mathematics and Computation 2024年第1期6卷 311-324页

作者： Bo dong Wei Wang Department of Mathematics University of Massachusetts DartmouthNorth DartmouthMA02747USA Department of Mathematics and Statistics Florida International UniversityMiamiFL33199USA

In this paper,numerical experiments are carried out to investigate the impact of penalty parameters in the numerical traces on the resonance errors of high-order multiscale discontinuous Galerkin(DG)methods(dong et *** j Sci Comput 66:321–345,2016;dong and Wang in j Comput Appl Math 380:1–11,2020)for a one-dimensional stationary Schrödinger *** work showed that penalty parameters were required to be positive in error analysis,but the methods with zero penalty parameters worked fine in numerical simulations on coarse *** this work,by performing extensive numerical experiments,we discover that zero penalty parameters lead to resonance errors in the multiscale DG methods,and taking positive penalty parameters can effectively reduce resonance errors and make the matrix in the global linear system have better condition numbers.

关键词： Discontinuous Galerkin(DG)method Multiscale method Resonance errors One-dimensional Schrödinger equation

Machine learning ensemble model prediction of northward shift in potato cyst nematodes(Globodera rostochiensis and ***)distribution under climate change conditions

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journal of Integrative Agriculture 2024年第10期23卷 3576-3591页

作者： Yitong He Guanjin Wang Yonglin Ren Shan Gao dong Chu Simon j.McKirdy Shandong Engineering Research Centre for Environment-friendly Agricultural Pest Management College of Plant Health andMedicineQingdao Agricultural UniversityQingdao 266109China Harry Butler Institute Murdoch UniversityMurdochWA 6150Australia School of Information Technology Murdoch UniversityPerthWA 6150Australia Hebei Dahaituo National Nature Reserve Management Centre Chicheng 075500China

Potato cyst nematodes(PCNs)are a significant threat to potato production,having caused substantial damage in many *** the future distribution of PCN species is crucial to implementing effective biosecurity strategies,especially given the impact of climate change on pest species invasion and *** learning(ML),specifically ensemble models,has emerged as a powerful tool in predicting species distributions due to its ability to learn and make predictions based on complex data ***,this research utilised advanced machine learning techniques to predict the distribution of PCN species under climate change conditions,providing the initial element for invasion risk *** first used Global Climate Models to generate homogeneous climate predictors to mitigate the variation among ***,five machine learning models were employed to build two groups of ensembles,single-algorithm ensembles(ESA)and multi-algorithm ensembles(EMA),and compared their *** this research,the EMA did not always perform better than the ESA,and the ESA of Artificial Neural Network gave the highest performance while being *** results indicated that the distribution range of PCNs would shift northward with a decrease in tropical zones and an increase in northern ***,the total area of suitable regions will not change significantly,occupying 16-20%of the total land surface(18%under current conditions).This research alerts policymakers and practitioners to the risk of PCNs’incursion into new ***,this ML process offers the capability to track changes in the distribution of various species and provides scientifically grounded evidence for formulating long-term biosecurity plans for their control.

关键词： invasive species distribution future climates homogeneous climate predictors single-algorithm ensembles multi-algorithm ensembles artificial neural network

Recent advancements in thermal conductivity of magnesium alloys

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journal of Magnesium and Alloys 2024年第5期12卷 1687-1708页

作者： Hao Lv jun Tan Qian Yuan Fanglei Wang Yunxuan Zhou Quan dong Aitao Tang jürgen Eckert Bin jiang Fusheng Pan National Engineering Research Center for Magnesium Alloys College of Materials Science and EngineeringChongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China Department of Materials Science Chair of Materials PhysicsMontanuniversität LeobenJahnstraße 12Leoben A-8700Austria Erich Schmid Institute of Materials Science Austrian Academy of SciencesJahnstraße 12Leoben A-8700Austria

As highly integrated circuits continue to advance,accompanied by a growing demand for energy efficiency and weight reduction,materials are confronted with mounting challenges pertaining to thermal conductivity and lightweight *** virtue of numerous intrinsic mechanisms,as a result,the thermal conductivity and mechanical properties of the Mg alloys are often inversely related,which becomes a bottleneck limiting the application of Mg *** on several effective modification methods to improve the thermal conductivity of Mg alloys,this paper describes the law of how they affect the mechanical properties,and clearly indicates that peak aging treatment is one of the best ways to simultaneously enhance an alloy's thermal conductivity and mechanical *** the most frequently used Mg alloy,cast alloys exhibit substantial potential for achieving high thermal ***,recent reports indicate that hot deformation can significantly improve the mechanical properties while maintaining,and potentially slightly enhancing,the alloy's thermal *** presents a meaningful way to develop Mg alloys for applications in the field of small-volume heat dissipation components that require high *** comprehensive review begins by outlining standard testing and prediction methods,followed by the theoretical models used to predict thermal conductivity,and then explores the primary influencing factors affecting thermal *** review summarizes the current development status of Mg alloys,focusing on the quest for alloys that offer both high thermal conductivity and high *** concludes by providing insights into forthcoming prospects and challenges within this field.

关键词： Mg alloy Thermal conductivity Mechanical properties Solute atom Second phase

Effects of Aging at 550℃ on α'-Martensitic Transformation of High Si-Bearing Metastable Austenitic Stainless Steel Weld Metal

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Acta Metallurgica Sinica(English Letters) 2024年第9期37卷 1467-1479页

作者： Yakui Chen Shitong Wei dong Wu Shanping Lu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The high Si-bearing 15Cr-9Ni-Nb metastable austenitic stainless steel weld metal was prepared via gas tungsten arc welding and then processed by stabilized heat treatment(SHT)at 850℃ for 3 *** effects of 550℃ aging on the α'-martensitic transformation of the as-welded and the SHT weld metals were *** results showed that the weld metal had poor thermal stability of *** precipitation of NbC during the 850℃ SHT made the thermal stability of the local matrix decrease and led to the formation of a large amount of C-depleted α'-*** precipitation of coarse σ-phase at the δ-ferrite led to the Cr-depleted zone and the formation of Cr-depleted α'-martensite at the early stage of 550℃ *** homogenized diffusion of C and Cr in the matrix during 550℃ aging led to the restoration of austenitic thermal stability and the decrease of α'-martensite *** C-depleted α'-martensite content in the SHT weld metal decreased rapidly at the early stage of aging due to the fast diffusion rate of the C atom in the matrix,while the Cr-depleted α'-martensite decreased at the later stage of aging due to the decreased diffusion rate of the Cr.

关键词： Metastable austenitic stainless steel weld metal α'-martensitic transformation δ-ferrite σ-phase

Eco-evolutionary evidence for the global diversity pattern of Cycas(Cycadaceae)

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journal of Integrative Plant Biology 2024年第6期66卷 1170-1191页

作者： jian Liu Anders jLindstrom Yiqing Gong Shanshan dong Yusheng(Chris)Liu Shouzhou Zhang Xun Gong CAS Key Laboratory for Plant Diversity and Biogeography of East Asia Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Department of Economic Plants and Biotechnology Yunnan Key Laboratory for Wild Plant ResourcesKunming Institute of BotanyChinese Academy of SciencesKunming 650201China University of Chinese Academy of Sciences Beijing 100049China Global Biodiversity Conservancy 144/124 Moo3Soi Bua ThongBangsalaeSattahipChonburi 20250Thailand Key Laboratory of Southern Subtropical Plant Diversity Fairy Lake Botanical GardenShenzhen&Chinese Academy of SciencesShenzhen 518004China Department of Earth and Environmental Sciences Indiana University-IndianapolisIndianapolisIN 46202USA

The evolution of the latitudinal diversity gradient(LDG),characterized by a peak in diversity toward the tropics,has captured significant attention in evolutionary biology and ***,the inverse LDG(i-LDG)mechanism,wherein species richness increases toward the poles,remains inadequately *** are among one of the oldest lineages of extant seed plants and have undergone extensive diversification in the ***,the extant cycad abundance exhibits an i-LDG pattern,and the underlying causes for this phenomenon remain largely ***,using 1,843 nuclear genes from a nearly complete sampling,we conducted comprehensive phylogenomic analyses to establish a robust species-level phylogeny for Cycas,the largest genus within *** then reconstructed the spatial-temporal dynamics and integrated global environmental data to evaluate the roles of species ages,diversification rates,contemporary environment,and conservatism to ancestral niches in shaping the i-LDG *** found Cycas experienced decreased diversification rates,coupled with the cooling temperature since its origin in the Eocene from continental *** regions have distinctively contributed to the formation of i-LDG for Cycas,with the northern hemisphere acting as evolutionary museums and the southern hemisphere serving as ***,water-related climate variables,specifically precipitation seasonality and potential evapotranspiration,were identified as paramount factors constraining Cycas species richness in the rainforest biome near the ***,the adherence to ancestral monsoonal climates emerges as a critical factor in sustaining the diversity *** study underscores the imperative of integrating both evolutionary and ecological approaches to comprehensively unravel the mechanisms underpinning global biodiversity patterns.

关键词： cycads latitudinal diversity gradient niche conservatism spatiotemporal diversification species richness

Overlooked uneven progress across sustainable development goals at the global scale: Challenges and opportunities

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The Innovation 2024年第2期5卷 42-50页

作者： Yali Liu jianqing Du Yanfen Wang Xiaoyong Cui jichang dong Pan Gu Yanbin Hao Kai Xue Hongbo Duan Anquan Xia Yi Hu Zhi dong Bingfang Wu jüurgen P.Kropp Bojie Fu School of Grassland Science Beijing Forestry UniversityBeijing 100083China Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of SciencesBeijing 101408China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory of Tibetan Plateau Earth System Environment and ResourcesChinese Academy of SciencesBeijing 100101China College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China School of Economics and Management University of Chinese Academy of SciencesBeijing 100190China School of Humanities University of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Adaptation and Evolution of Plateau Biota Northwest Institute of Plateau BiologyChinese Academy of SciencesXining 810001China School of Innovation and Entrepreneurship University of Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Remote Sensing Science Aerospace Information Research InstituteChinese Academy of SciencesBeijing 100101China Potsdam Institute for Climate Impact Research 14412 PotsdamGermany Institute for Environmental Science and Geography University of Potsdam14412 PotsdamGermany State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

Differences in progress across sustainable development goals(SDGs)are widespread globally;meanwhile,the rising call for prioritizing specific SDGs may exacerbate such ***,how these progress differences would influence global sustainable development has been long ***,we present the first quantitative assessment of SDGs’progress differences globally by adopting the SDGs progress evenness *** results highlight that the uneven progress across SDGs has been a hindrance to sustainable development because(1)it is strongly associated with many public health risks(e.g.,air pollution),social inequalities(e.g.,gender inequality,modern slavery,wealth gap),and a reduction in life expectancy;(2)it is also associated with deforestation and habitat loss in terrestrial and marine ecosystems,increasing the challenges related to biodiversity conservation;(3)most countries with low average SDGs performance show lower progress evenness,which further hinders their fulfillment of SDGs;and(4)many countries with high average SDGs performance also showcase stagnation or even retrogression in progress evenness,which is partly ascribed to the antagonism between climate actions and other *** findings highlight that while setting SDGs priorities may be more realistic under the constraints of multiple global stressors,caution must be exercised to avoid new problems from intensifying uneven progress across ***,our study reveals that the urgent needs regarding SDGs of different regions seem complementary,emphasizing that regional collaborations(e.g.,demand-oriented carbon trading between SDGs poorly performed and well-performed countries)may promote sustainable development achievements at the global scale.

关键词： globally priori inequality