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Hierarchical Community Detection Based on Partial Matrix Convergence Using Random Walks

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Tsinghua Science and Technology 2018年第1期23卷 35-46页

作者： Wei zhang Feng Kong Liming Yang Yunfang Chen mengyuan zhang School of Computer Science Nanjing University of Posts and Telecommunications and Jiangsu High Technology Research Key Laboratory for Wireless Sensor Networks Nanjing 210023 China. Chen are with School of Computer Science Nanjing University of Posts and Telecommunications Nanjing 210023 China Concordia Institution System Engineering (CIISE) Concordia University Montreal QC H3G 1M8 Canada.

Random walks are a standard tool for modeling the spreading process in social and biological systems But in the face of large-scale networks, to achieve convergence, iterative calculation of the transition matrix in random walk methods consumes a lot of time. In this paper, we propose a three-stage hierarchical community detection algorithm based on Partial Matrix Approximation Convergence （PMAC） using random walks. First, this algorithm identifies the initial core nodes in a network by classical measurement and then utilizes the error function of the partial transition matrix convergence of the core nodes to determine the number of random walks steps. As such, the PMAC of the core nodes replaces the final convergence of all the nodes in the whole matrix. Finally based on the approximation convergence transition matrix, we cluster the communities around core nodes and use a closeness index to merge two communities. By recursively repeating the process, a dendrogram of the communities is eventually constructed. We validated the performance of the PMAC by comparing its results with those of two representative methods for three real-world networks with different scales

关键词： community detection random walks transition matrix clustering

Optimal Operation with Dynamic Partitioning Strategy for Centralized Shared Energy Storage Station with Integration of Large-scale Renewable Energy

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 359-370页

作者： Jianlin Li Zhijin Fang Qian Wang mengyuan zhang Yaxin Li Weijun zhang Beijing Future Technology Innovation Centre for Electrochemical Energy Storage System Integration North China University of Technology Beijing China State Grid Fujian Electric Power Research Institute Fuzhou China

As renewable energy continues to be integrated into the grid,energy storage has become a vital technique supporting power system *** effectively promote the efficiency and economics of energy storage,centralized shared energy storage(SES)station with multiple energy storage batteries is developed to enable energy trading among a group of *** this paper,we propose the optimal operation with dynamic partitioning strategy for the centralized SES station,considering the day-ahead demands of large-scale renewable energy power *** implement a multi-entity cooperative optimization operation model based on Nash bargaining *** model is decomposed into two subproblems:the operation profit maximization problem with energy trading and the leasing payment bargaining *** distributed alternating direction multiplier method(ADMM)is employed to address the subproblems *** reveal that the optimal operation with a dynamic partitioning strategy improves the tracking of planned output of renewable energy entities,enhances the actual utilization rate of energy storage,and increases the profits of each participating *** results confirm the practicality and effectiveness of the strategy.

关键词： Shared energy storage(SES) dynamic partitioning strategy optimal operation Nash bargaining theory actual utilization rate of energy storage

Resource Scheduling Strategy for Performance Optimization Based on Heterogeneous CPU-GPU Platform

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Computers, Materials & Continua 2022年第10期73卷 1621-1635页

作者： Juan Fang Kuan Zhou mengyuan zhang Wei Xiang Faculty of Information Technology Beijing University of TechnologyBeijing100124China La Trobe University MelbourneVIC3086Australia James Cook University CainsQLD4878Australia

In recent years,with the development of processor architecture,heterogeneous processors including Center processing unit(CPU)and Graphics processing unit(GPU)have become the ***,due to the differences of heterogeneous core,the heterogeneous system is now facing many problems that need to be *** order to solve these problems,this paper try to focus on the utilization and efficiency of heterogeneous core and design some reasonable resource scheduling *** improve the performance of the system,this paper proposes a combination strategy for a single task and a multi-task scheduling strategy for multiple *** combination strategy consists of two sub-strategies,the first strategy improves the execution efficiency of tasks on the GPU by changing the thread organization *** second focuses on the working state of the efficient core and develops more reasonable workload balancing schemes to improve resource utilization of heterogeneous *** multi-task scheduling strategy obtains the execution efficiency of heterogeneous cores and global task information through the processing of task *** on this information,an improved ant colony algorithm is used to quickly obtain a reasonable task allocation scheme,which fully utilizes the characteristics of heterogeneous *** experimental results show that the combination strategy reduces task execution time by 29.13%on *** the case of processing multiple tasks,the multi-task scheduling strategy reduces the execution time by up to 23.38%based on the combined *** strategies can make better use of the resources of heterogeneous systems and significantly reduce the execution time of tasks on heterogeneous systems.

关键词： Heterogeneous computing CPU-GPU Performance Workload balance

10Be Exposure Ages Obtained From Quaternary Glacial Landforms on the Tibetan Plateau and in the Surrounding Area

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Acta Geologica Sinica(English Edition) 2018年第2期92卷 786-800页

作者： zhang mengyuan MEI Jing zhang Zhigang WANG Jian XU Xiaobin School of Geographical Sciences Nanjing Normal University Nanjing 210023 China Key Laboratory of Virtual Geographic Environment (Nanjing Normal University) Ministry of Education Nanjing 210023 China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing 210023 China State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou 730000 China School of Urban and Resource Environment Jiangsu Second Normal University Nanjing 210024 China

In situ terrestrial cosmogenic nuclide （TCN） exposure dating using 10Be is one of the most successful techniques used to determine the ages of Quaternary deposits and yields data that enable the reconstruction of the Quaternary glacial history of the Tibetan Plateau and the surrounding mountain ranges. Statistical analysis of TCN 10Be exposure ages, helps to reconstruct the history of glacial fluctuations and past climate changes on the Tibetan Plateau, differences in the timing of glacier advances among different regions. However, different versions of the Cosmic-Ray-prOduced NUclide Systematics on Earth （CRONUS-Earth） online calculator, which calculates and corrects the TCN ages of Quaternary glacial landforms, yield different results. For convenience in establishing contrasts among regions, in this paper, we recalculate 1848 10Be exposure ages from the Tibetan Plateau that were published from 1999 to 2017 using version 2.3 of the CRONUS-Earth calculator. We also compare the results obtained for 1594 10Be exposure ages using different versions （2.2, 2.3 and 3.0） of the CRONUS- Earth calculator. The results are as follows. （1） Approximately 97% of the exposure ages are less than 200 ka. A probability density curve of the exposure ages suggests that greater numbers of oscillations emerge during the Holocene, and the peaks correspond to the Little Ice Age, the 8.2 ka and 9.3 ka cold events; the main peak covers the period between 12 and 18 ka. （2） In most areas, the newer versions of the calculator produce older 10Be exposure ages. When different versions of the CRONUS-Earth calculator are used, approximately 29% of the 10Be exposure ages display maximum differences greater than 10 ka, and the maximum age difference for a single sample is 181.1 ka.

关键词： 10Be probability density curves in situ terrestrial cosmogenic nuclides CRONUS-Earth,Tibetan Plateau

Regional source contributions to fine particulate matter of less studied cities in Beijing-Tianjin-Hebei region in 2017

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Particuology 2023年第11期82卷 111-121页

作者： Qixian Liu mengyuan zhang Pengfei Wang Kaiyu Chen Peng Wang Yi zhang Baojun zhang Hongliang zhang Department of Environmental Science and Engineering Fudan UniversityShanghai200438China Department of Civil and Environmental Engineering Louisiana State UniversityBaton RougeLA70803USA Department of Chemical Engineering University of UtahSalt Lake City84112USA Department of Atmospheric and Marine Sciences Fudan UniversityShanghai200438China IRDR ICoE on Risk Interconnectivity and Governance on Weather/Climate Extremes Impact and Public Health Fudan UniversityShanghai200438China Tangshan Ecological Environment Publicity and Education Center TangshanHebei063000China Institute of Eco-Chongming Shanghai200062China

Located in the central area of the North China Plain, the Beijing-Tianjin-Hebei region experiences severe air pollution, especially for Hebei province with five cities among the top 10 cities with the worst air quality nationwide. However, less studies have investigated local and regional contributions to cities in Hebei in comparison to Beijing and Tianjin. In this study, a source-oriented version of the Community Multiscale Air Quality (CMAQ) model is used to quantify inter- and intra-province transport of PM_(2.5) in 11 cities within Hebei in 2017. PM_(2.5) and its components vary seasonally with high levels in winter and low levels in summer. Local contributions to total PM_(2.5) within cities are 23%–61%, while intra-province transport contributes 10%–30%, and inter-province transport contributes 23%–46%, with top contributors of Shandong (4%–22%), Henan (3%–15%) and Shanxi (2%–11%). The primary components in most cities are mainly from local sources (30%–80%), and the secondary components are mainly from inter-province contributions (30%–66%). Local sources have the highest contributions to total PM_(2.5) in Shijiazhuang (∼49%), followed by Shanxi (∼12%) and Xingtai (∼7%). Secondary components from local and intra-province emissions are the major cause of heavy pollution events. These results suggest that both local and regional joint control measures with neighboring cities and provinces are necessary for pollution reduction in Hebei cities.

关键词： PM_(2.5) Source-oriented Hebei Regional contributions Community Multiscale Air Quality(CMAQ) model

A ratiometric fluorescent nanoprobe based on ZIF-8@AuNCs-Tb for visual detection of 2,6-pyridinedicarboxylic acid

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Journal of Rare Earths 2022年第8期40卷 1165-1172页

作者： Kang Shao Siyu Wen mengyuan zhang Jing Wang Shiyi Ye Zaifa Pan College of Chemical Engineering Zhejiang University of TechnologyHangzhou 310014China Institute of Animal Husbandry and Veterinary Science Zhejiang Academy of Agricultural SciencesHangzhou 310002China College of Life Science Yangtze UniversityJingzhou 434023China

The rapid and sensitive detection of 2,6-pyridinedicarboxylic acid(DPA),one of the main biomarkers of Bacillus anthracis,is of great significance for the screening and diagnosing of ***,a ratiometric fluorescent nanoprobe based on zeolite imidazolate framework-8(ZIF-8)@AuNCs-Tb was constructed by embedding both gold nanoclusters(AuNCs)and terbium ions(Tb^(3+))into ZIF-8 for highresolution visual detection of *** to the aggregation induced emission enhancement(AIE)effect,AuNCs embedded in ZIF-8 emit a strong orange *** Tb^(3+)is coordinated with DPA added to the nanoprobe,it will emit a strong green fluorescence owing to the antenna *** results reveal that ZIF-8@AuNCs-Tb nanoprobe can detect DPA effectively with a good linear relationship in the range of 40-200 and 200-1000μmol/L,the limit of detection(LOD)is estimated at 1.8μmol/L(3σ/k).The proposed nanoprobe shows a remarkable selectivity for DPA and is quite easy to realize visualization based on the fluorescent color changing from orange to green,which has potential application in clinical *** feasibility of this method was verified by standard addition recovery experiments simulating the release of DPA from spores.

关键词： Terbium ions Ratiometric fluorcscent nanoprobe Visual detection Gold nanoclusters Zeolite imidazolate framework-8 Rare earths

Hemolysis of PM_(10) on RBCs in vitro:An indoor air study in a coal-burning lung cancer epidemic area

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Geoscience Frontiers 2022年第1期13卷 506-511页

作者： mengyuan zhang Longyi Shao Tim Jones Ying Hu Rachel Adams Kelly BéruBé State Key Laboratory of Coal Resources and Safe Mining and College of Geoscience and Surveying EngineeringChina University of Mining&TechnologyBeijing 100083China School of Earth and Environmental Sciences Cardiff UniversityMuseum AvenueCardiff CF103YEUK Guangdong Province Nuclear Industry Geological Bureau Guangzhou 510800China School of Health Sciences Cardiff Metropolitan UniversityLlandaff CampusWestern AvenueCardiff CF52YBWalesUK School of Biosciences Cardiff UniversityMuseum AvenueCardiff CF103AXWalesUK

Epidemiological studies have suggested that inhalation exposure to indoor ambient air from coal-burning environments is causally associated with respiratory health *** order to explore the toxicological mechanisms behind the adverse health effects,the hemolytic activity of PM_(10)(particulate matter with an aerodynamic diameter of 10 um or less)samples collected from homes burning coal in the recognized China"cancer village"Xuanwei were evaluated and matched against their trace elemental *** results demonstrated that the hemolytic activity of indoor PM_(10) in coal-burning environments ranged from 4.28%to 5.24%,with a clear positive dose-response *** low dose samples exhibited a reduced hemolytic activity,PM_(10) could have a toxic effect upon people in a coal-burning indoor environment for extended time *** concentrations of analyzed trace elements in PM_(10) samples ranged from 6966 to 12,958 *** the analyzed elements,Zn,Ti,Ni,Cu,Pb,Ba,Mn,Cr and V were found at higher concentrations and accounted for over 95%of the total *** concentrations of total analyzed elements in the PM_(10) samples revealed a significant positive correlation with PM_(10) hemolytic *** the analyzed elements,Zn,Pb and Cs positively correlated with hemolysis,while Li,U and V negatively correlated with the hemolysis of human red blood cells(RBCs).Therefore,the heavy metal elements could be one of the main factors responsible for the hemolytic capacity of indoor PM_(10) in coal-burning environments.

关键词： Air pollution PM_(10) Coal Hemolysis Xuanwei County

Evaluating Optimal Treatment for Melanoma:A Network Meta-Analysis

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Chinese Journal of Plastic and Reconstructive Surgery 2021年第1期3卷 27-31页

作者： mengyuan zhang Qiong HE Yuifang YU Baolin zhang Department of Plastic Surgery First Hospital of Shanxi Medical UniversityTaiyuanShanxi 030001China Department of Endocrinology.First Hospital of Shanxi Medical University TaiyuanShanxi 030001China

Background It is necessary to determine the optimal treatment for melanoma as the incidence of melanoma is increasing every *** this study,we conducted a metaanalysis to compare the effectiveness of available treatments for *** The index keywords“melanoma”and“treatment”were used to search the PubMed,Cochrane Library,Web of Science,and Embase databases,and the articles were limited to randomized controlled *** search was filtered for articles published until February 2020,and articles were independently extracted by two *** metaanalysis(Stata®14.0 software network package,StataCorp LLC,TX,USA)was used to compare the effectiveness of the mentioned treatments of *** A total of 616 articles were screened of which 6 were selected for meta-analysis,involving 5 treatment measures and 2047 patients(those who were not followed up on were excluded).The treatment strategies reported for melanoma included tumor necrosis factor(L19-TNFα)and interleukin-2(L19IL2)in combination with dacarbazine(L19IL2+DTIC),DTIC,programmed cell death-1 plus cytotoxic T cell antigen-4(PD-1+CTLA-4),PD-1,and *** Among L19IL2+DTIC,DTIC,PD-1+CTLA-4,PD-1,and CTLA-4,CTLA-4 is found to be the best treatment method for *** study findings provide a reference for the clinical treatment of melanoma and can clarify the direction for setting up controlled clinical trials.

关键词： Melanoma treatment Network Meta-analysis

Kinetics of Catalyzed Thermal Degradation of Polylactide and Its Application as Sacrificial Templates

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Chinese Journal of Chemistry 2022年第23期40卷 2801-2807,I0002页

作者： Li Feng Chenhui Cui Zhen Li mengyuan zhang Shenghui Gao Qiang zhang Youshen Wu Zhishen Ge Yilong Cheng Yanfeng zhang School of Chemistry Xi'an Jiaotong UniversityXianShaanxi 710049China Shaanxi Yuneng Group Energy and Chemical Industry Research Institute Co. Ltd.YulinShaanxi 719000China

Polylactide(PLA)is an outstanding sacrificial template material for the manufacture of microchannels in a thermosetting ***,the initial thermal degradation temperature of pure PLA is relatively high(about 280℃),which limits its use as a sacrificial *** this report,we found that TBD,an organic base catalyst,can significantly reduce the thermal degradation temperature of *** has higher catalytic activity for the thermal degradation of PLA compared with Tin(II)oxalate(Sn(Oxa)),one catalyst reported in the ***,the gaseous products catalyzed by TBD for PLA thermal degradation are mainly lactide,and the formation temperature of the monomer is lower and the yield is higher,which may have potential value for PLA recycling.A combined catalyst,S8T2,was composed of 80%low activity catalyst Sn(Oxa)and 20%high activity catalyst TBD,which can catalyze the rapid degradation of PLA without greatly damaging the mechanical properties of ***-S8T2 sacrificial fibers can form high-precision one-dimensional microchannels in the epoxy resin matrix,and 3D-printed PLA-S8T2 sacrificial templates can be used to form three-dimensional microchannels in a thermosetting matrix by vaporization of sacrificial components process(VaSC).These features highlight the great potential of PLA-S8T2 as sacrificial template material for the preparation of the complicated microchannels in the thermosetting matrix.

关键词： Polymers Gaseous product Kinetics Sacrificial template Microchannel