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pyvine:The Python Package for Regular Vine Copula Modeling,Sampling and Testing

Communications in Mathematics and Statistics 2021年第1期9卷 53-86页

作者： Zhenfei Yuan Taizhong hu Department of Statistics and Finance School of ManagementUniversity of Science and Technologyof ChinaHefei 230026AnhuiChina

Regular vine copula provides rich models for dependence structure *** combines vine structures and families of bivariate copulas to construct a number of multivariate distributions that can model a wide range dependence patterns with different tail dependence for different *** special cases of regular vine copulas,C-vine and D-vine copulas,have been extensively investigated in the *** propose the Python package,pyvine,for modeling,sampling and testing a more generalized regular vine copula(R-vine for short).R-vine modeling algorithm searches for the R-vine structure which maximizes the vine tree dependence in a sequential *** maximum likelihood estimation algorithm takes the sequential estimations as initial values and uses L-BFGS-B algorithm for the likelihood value optimization.R-vine sampling algorithm traverses all edges of the vine structure from the last tree in a recursive way and generates the marginal samples on each edge according to some nested ***-of-fit testing algorithm first generates Rosenblatt’s transformed data E and then tests the hypothesis H^(∗)_(0):E∼C_(⊥)by using Anderson–Darling statistic,where C_(⊥)is the independence *** method is used to compute an adjusted p-value of the empirical distribution of replications of Anderson–Darling *** computing of related functions of copulas such as cumulative distribution functions,Hfunctions and inverse H-functions often meets with the problem of *** solve this problem by reinvestigating the following six families of bivariate copulas:Normal,Student t,Clayton,Gumbel,Frank and Joe’s *** of the above related functions of copulas are given when the overflow occurs in the *** these are implemented in a subpackage bvcopula,in which subroutines are written in Fortran and wrapped into Python and,hence,good performance is guaranteed.

关键词： Regular vine copula Dependence structure Multivariate modeling Multivariate sampling Rosenblatt’s transformation Anderson–Darling test Bivariate copula Python

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Hybrid battery integrated by Zn-air and Zn-Co3O4 batteries at cell level

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Journal of Energy Chemistry 2020年第10期29卷 375-383页

作者： Ning Liu Honglu hu Xinxin Xu Qiang Wang Department of Chemistry College of ScienceNortheastern UniversityShenyang 110819LiaoningChina Key Laboratory of Electromagnetic Processing of Materials MOENortheastern UniversityShenyang 110819LiaoningChina

The construction of Zn based hybrid battery through the combination of Zn-air and Zn-Co3O4 batteries at cell level is a feasible strategy to integrate high voltage,specific capacity and energy density in one power supply *** Zn based hybrid battery,an efficient cathode material with high specific capacitance and excellent ORR,OER activities is a vital component,which determines its performance in great *** this work,with Co based coordination polymer as precursor,oxygen vacancy-rich Co3 O4 based cathode material is *** this material Co3O4 particles with the size about 20 to 35 nm reside evenly in mesoporous carbon matrix doped by nitrogen *** OER,the overpotential of this cathode material is merely 330 m *** ORR proceeds with a typical four electron process with half wave achieving 0.76 *** charge/discharge at 1 A·g^-1,specific capacitance of this cathode material is 254.4 mAh·g^-*** current density increases to 20 A·g^-1,the specific capacitance still arrives at 122.5 mAh·g^-1 with nearly 50%*** on attractive performance of this cathode material,Zn based hybrid battery is *** discharge at 1 m A·cm-2,it presences two voltage platforms at 1.71 and 1.14 *** this situation,specific capacitance reaches 790 m Ah·g^-1 with energy density 928 Wh·kg^-*** battery shows promising stability after 300-cycle continuous test.

关键词： Zn based battery Hybrid battery Oxygen vacancy Electrocatalysis Co3O4

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An Efficient Summer Operation Scheme for a Thermal Power Plant Air Cooling System based on Electric Peak Shaving

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Journal of Thermal Science 2020年第2期29卷 393-407页

作者： hu hemin LIANG Shiqiang JIANG Yuyan GUO Yongxian heat and Mass Transter Research Center Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

We proposed a novel efficient operation scheme for a thermal power plant’s air-cooling system based on peak shaving, in order to cope with high ambient temperature in summer. We introduced an absorptiongeneration equipment with water/lithium working pairs into the air cooled condenser(ACC) to reconstruct the traditional thermal power plant, and established a dynamic thermodynamic model adopting Ebsilon code. We studied the thermodynamic performance variation of the reconstructed thermal power plant throughout a 24-hour cycle and found that the fluctuation ratio of the turbine back pressure decreased to 6% from 78%, which is beneficial for the stable and safe operation of the electric power system. The thermal performance improvement benefited from the exploitation of the heat transfer potential of ACC, which realized via cold duty schedule throughout the day, under different ambient temperature conditions. In this system, the generated power was higher at relatively high ambient temperature than that at relatively low ambient temperature, which solved the electricity demand-supply imbalance problem under high ambient temperature. Finally, the same optimization effects for power thermal plants with an indirect air-cooling system were obtained using the same operation scheme.

关键词： thermal power reconstruction air cooled condenser(ACC) indirect air cooling system peak-shaving absorption-generation equipment

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Incremental join view maintenance on distributed log-structured storage

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Frontiers of Computer Science 2021年第4期15卷 105-120页

作者： huichao DUAN huiqi hu Weining QIAN Aoying ZHOU School of Data Science and Engineering East China Normal UniversityShanghai 200062China

Modern database systems desperate for the ability to support highly scalable transactions and efficient queries simultaneously for real-time *** solution is to utilize query optimization techniques on the on-line transaction processing(OLTP)*** materialized view is considered as a panacea to decrease query ***,it also involves the significant cost of maintenance which trades away transaction *** this paper,we examine the design space and conclude several design features for the implementation of a view on a distributed log-structured merge-tree(LSMtree),which is a well-known structure for improving data write *** a result,we develop two incremental view maintenance(IVM)approaches on *** avoids join computation in view maintenance *** with two optimizations is proposed to decouple the view maintenance with the transaction *** the asynchronous update,we also provide consistency queries for *** on TPC-H benchmark show our methods achieve better performance than straightforward methods on different workloads.

关键词： materialized views asynchronous maintenance hybrid transaction and analytical process LSM-tree

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Resource optimization in wireless powered cooperative mobile edge computing systems

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Science China(Information Sciences) 2021年第8期64卷 56-65页

作者： Qibin YE Weidang LU Su hu Xiaohan XU National Key Laboratory on Communications University of Electronic Science and Technology of China College of Information Engineering Zhejiang University of Technology

Mobile edge computing(MEC) meets the high-bandwidth and ultra-low-latency requirements of mobile networks and improves communication reliability by reducing the networks’ load. In this study, we study a wireless powered MEC system, which includes an access point(AP) and two mobile devices. The endurance of mobile devices can be effectively enhanced using the wireless power transfer technology and user cooperation. However, during user cooperation, a closer user assists a farther user with forwarding tasks by sharing the same bandwidth, which causes interference. To overcome the interference issue, the closer user can instead assist other users in forwarding tasks by using a different bandwidth. We aim to minimize the power of the AP by joint power and bandwidth optimization while satisfying the delay and users’ computational tasks. Simulation results show that the proposed user collaboration method can overcome user interference,reduce energy consumption, and improve user performance compared with the baseline policies.

关键词： mobile edge computing user cooperation wireless power transfer energy consumption resource management

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Role of epithelial-mesenchymal transition in chemoresistance in pancreatic ductal adenocarcinoma

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World Journal of Clinical Cases 2021年第19期9卷 4998-5006页

作者： Xiu hu Wei Chen Department of Pharmacy Affiliated Hangzhou Cancer HospitalZhejiang University School of MedicineHangzhou 310002Zhejiang ProvinceChina Cancer Institute of Integrated Traditional Chinese and Western Medicine Key Laboratory of Cancer Prevention and Therapy Combining Traditional Chinese and Western Medicine of Zhejiang ProvinceZhejiang Academy of Traditional Chinese MedicineTongde Hospital of Zhejiang ProvinceHangzhou 310012Zhejiang ProvinceChina

Pancreatic cancer(PC)is the seventh leading cause of cancer death *** vast majority of patients who have PC develop metastases,resulting in poor treatment *** great progress in therapeutic approaches has been achieved in recent decades,extensive drug resistance still persists,representing a major hurdle to effective anticancer therapy for pancreatic ductal adenocarcinoma(PDAC).Therefore,there is an urgent need to better understand the drug resistance mechanisms and develop novel treatment strategies to improve patient *** studies suggest that chemoresistance is closely related to epithelial-mesenchymal transition(EMT)of PDAC ***,this article summarizes the impact of EMT on PDAC from the perspective of chemotherapy resistance and discusses the possible novel applications of EMT inhibition to develop more effective drugs against PDAC.

关键词： Epithelial-mesenchymal transition Drug resistance Carcinoma Pancreatic ductal Transcription factors MicroRNAs

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组织传播中战略模糊性命题的伦理辩护

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山东社会科学 2009年第8期 21-25页

作者：胡河宁温州医学院组织传播研究所浙江温州325035

战略模糊性是组织传播中的一个重要命题,是一个客观存在的组织传播现象。加强组织的伦理文化建设,澄清管理者的伦理价值观念,把握决定瞬间的伦理机智,组织传播中的战略模糊性在实现组织利益的同时,也能实现最大限度的诚实和善意。

关键词：战略模糊性组织传播组织伦理

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Extrapolation cascadic multigrid method on piecewise uniform grid

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Science China Mathematics 2013年第12期56卷 2711-2722页

作者： CheN ChuanMiao hu HongLing College of Mathematics and Computer Science Key Laboratory of High Performance Computing and Stochastic Information Processing (Ministry of Education of China)Hunan Normal University

The triangular linear finite elements on piecewise uniform grid for an elliptic problem in convex polygonal domain are discussed. Global superconvergence in discrete Hi-norm and global extrapolation in discrete L2-norm are proved. Based on these global estimates the conjugate gradient method （CG） is effective, which is applied to extrapolation cascadic multigrid method （EXCMG）. The numerical experiments show that EXCMG is of the global higher accuracy for both function and gradient.

关键词： linear finite element piecewise uniform grid superconvergence extrapolation extrapolation cas-cadic multigrid method

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Adult neural stem cells and schizophrenia

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World Journal of Stem Cells 2022年第3期14卷 219-230页

作者： Ling hu Lei Zhang Department of Laboratory Animal Science and Institutes of Brain Science Fudan UniversityShanghai 200032China Shanghai Yangzhi Rehabilitation Hospital(Shanghai Sunshine Rehabilitation Center)and Department of Anatomy and Neurobiology Tongji University School of MedicineShanghai 200092China

Schizophrenia(SCZ)is a devastating and complicated mental disorder accompanied by variable positive and negative symptoms and cognitive *** many genetic risk factors have been identified,SCZ is also considered as a neurodevelopmental *** of the pathogenesis and the development of treatment is challenging because complex interactions occur between these genetic risk factors and environment in essential neurodevelopmental *** neural stem cells share a lot of similarities with embryonic neural stem cells and provide a promising model for studying neuronal development in *** adult neural stem cells also play an important role in cognitive functions including temporal and spatial memory encoding and context discrimination,which have been shown to be closely linked with many psychiatric disorders,such as *** in this review,we focus on the SCZ risk genes and the key components in related signaling pathways in adult hippocampal neural stem cells and summarize their roles in adult neurogenesis and animal *** hope that this would be helpful for the understanding of the contribution of dysregulated adult neural stem cells in the pathogenesis of SCZ and for the identification of potential therapeutic targets,which could facilitate the development of novel medication and treatment.

关键词： Neural stem cells Adult hippocampal neurogenesis Schizophrenia Risk genes Signaling pathways Behavior

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NONLINEAR DYNAMIC MODELING AND PERIODIC VIBRATION OF A CANTILEVER BEAM SUBJECTED TO AXIAL MOVEMENT OF BASEMENT

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Acta Mechanica Solida Sinica 2002年第2期15卷 133-139页

作者： Feng Zhihua hu Haiyan Nanjing Univ Aeronaut & Astronaut Inst Vibrat Engn Res Nanjing 210016 Peoples R China

Dynamic modeling of a cantilever beam under an axial movement ofits basement is present- ed. The dynamic equation of motion for thecantilever beam is established by using Kane's equation first andthen simplified through the Rayleigh-Ritz method. Compared with oldermodeling method, which lineari- zes the generalized inertia forcesand the generalized active forces, the present modeling takes thecoupled cubic nonlinearities of geometrical and inertial types intoconsideration.

关键词： cantilever beam parametric excitation dynamic modeling nonlinear dynamics

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