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A star-based method for precise wavelength calibration of the Chinese Space Station Telescope(CSST) slitless spectroscopic survey

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Research in Astronomy and Astrophysics 2021年第3期21卷 235-242页

作者： Hai-Bo Yuan Ding-shan deng Yang Sun Department of Astronomy Beijing Normal UniversityBeijing 100875China

The Chinese Space Station Telescope(CSST)spectroscopic survey aims to deliver high-quality low-resolution(R>200)slitless spectra for hundreds of millions of targets down to a limiting magnitude of about 21 mag,distributed within a large survey area(17500 deg2)and covering a wide wavelength range(255-1000 nm by three bands GU,GV,and GI).As slitless spectroscopy precludes the usage of wavelength calibration lamps,wavelength calibration is one of the most challenging issues in the reduction of slitless spectra,yet it plays a key role in measuring precise radial velocities of stars and redshifts of *** this work,we propose a star-based method that can monitor and correct for possible errors in the CSST wavelength calibration using normal scientific observations,taking advantage of the facts that(ⅰ)there are about ten million stars with reliable radial velocities now available thanks to spectroscopic surveys like LAMOST,(ⅱ)the large field of view of CSST enables efficient observations of such stars in a short period of time,and(ⅲ)radial velocities of such stars can be reliably measured using only a narrow segment of CSST *** demonstrate that it is possible to achieve a wavelength calibration precision of a few km s^(-1) for the GU band,and about 10 to 20 kms^(-1) for the GV and GI bands,with only a few hundred velocity standard *** of the method to other surveys are also discussed.

关键词： methods:data analysis methods:statistical techniques:spectroscopic techniques:radial velocities stars:fundamental parameters stars:kinematics and dynamics

An Information Entropy-Based Methodology to Construct the Avulsion Threshold in the Tail Reach of the Estuarine Alluvial Plain

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China Ocean Engineering 2023年第5期37卷 794-806页

作者： YANG Zhuo-yuan XIA Jun-qiang deng shan-shan ZHOU Mei-rong JI Zu-wen YU Xin State Key Laboratary of Water Resources and Management Wuhan UniversityWuhan 430072China Changjiang Survey PlanningDesign and Research Co.LtdWuhan 430010China State Key Laboratary of Simulation and Regulation of River Basin Water Cycle China Insititute of Water Resources and Hydropower ResearchBeijing 100048China Yellow River Institute of Hydraulic Research Yellow River Conservancy CommisionZhengzhou 450003China

Channel avulsion is a natural phenomenon that occurs abruptly on alluvial river deltas,which can affect the channel *** causes for avulsion could be generally categorized as topography-and flood-driven ***,previous studies on avulsion thresholds usually focused on topography-driven factors due to the centurial or millennial avulsion timescales of the world’s most deltas,but neglected the impacts of flood-driven *** the current study,a novel demarcation equation including the two driven factors was proposed,with the decadal timescale of avulsion being considered in the Yellow River Estuary(YRE).In order to quantify the contributions of different factors in each category,an entropy-based methodology was used to calculate the contributing weights of these *** factor with the highest weight in each category was then used to construct the demarcation equation,based on avulsion datasets associated with the *** avulsion threshold was deduced according to the demarcation *** avulsion threshold was then applied to conduct the risk assessment of avulsion in the *** results show that:two dominant factors cover respectively geomorphic coefficient representing the topography-driven factor and fluvial erosion intensity representing the flood-driven factor,which were thus employed to define a two dimensional mathematical space in which the demarcation equation can be obtained;the avulsion threshold derived from the equation was also applied in the risk assessment of avulsion;and the avulsion threshold proposed in this study is more accurate,as compared with the existing thresholds.

关键词： avulsion threshold threshold conditions entropy weight method tail reach Yellow River Estuary

A Weighted Runge-Kutta Method with Weak Numerical Dispersion for Solving Wave Equations

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Communications in Computational Physics 2010年第5期7卷 1027-1048页

作者： shan Chen Dinghui Yang Xiaoying deng Department of Mathematical Sciences Tsinghua UniversityBeijing 100084China

In this paper, we propose a weighted Runge-Kutta (WRK) method to solvethe 2D acoustic and elastic wave equations. This method successfully suppresses thenumerical dispersion resulted from discretizing the wave equations. In this method,the partial differential wave equation is first transformed into a system of ordinarydifferential equations (ODEs), then a third-order Runge-Kutta method is proposedto solve the ODEs. Like the conventional third-order RK scheme, this new methodincludes three stages. By introducing a weight to estimate the displacement and itsgradients in every stage, we obtain a weighted RK (WRK) method. In this paper, weinvestigate the theoretical properties of the WRK method, including the stability criteria, numerical error, and the numerical dispersion in solving the 1D and 2D scalarwave equations. We also compare it against other methods such as the high-ordercompact or so-called Lax-Wendroff correction (LWC) and the staggered-grid *** validate the efficiency and accuracy of the method, we simulate wave fields in the2D homogeneous transversely isotropic and heterogeneous isotropic media. We conclude that the WRK method can effectively suppress numerical dispersions and sourcenoises caused in using coarse grids and can further improve the original RK methodin terms of the numerical dispersion and stability condition.

关键词： WRK method seismic wavefield modeling anisotropy numerical dispersion

A new formula of recovery factor for non-equilibrium transport of graded suspended sediment in the Middle Yangtze River

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Journal of Mountain Science 2023年第1期20卷 87-100页

作者： LI Lin-lin XIA Jun-qiang ZHOU Mei-rong deng shan-shan LI Zhi-wei State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China School of Civil Engineering Architecture and EnvironmentHubei University of TechnologyWuhan430068China

Suspended sediment concentrations in the Middle Yangtze River(MYR)reduced greatly after the Three Gorges Project operation,causing the composition of bed material to coarsen ***,little is known about the non-equilibrium transport of graded suspended sediment owing to different bed material compositions(BMCs)along the MYR,and it is necessary to determine the magnitude of recovery *** the Markov stochastic process in conjunction with the hiding-exposure effect of non-uniform bed-material,a new formula is proposed for calculating the recovery factor including the effect of different BMCs,and it is incorporated into the non-equilibrium transport equation to simulate the recovery processes of suspended load in both sand-gravel bed and sand bed reaches of the *** results show that:(i)the recovery rate of graded sediment concentrations at Zhicheng was slower than that at Shashi during the period 2003-2007;(ii)the mean recovery factors of the coarse,medium,and fine sediment fractions in the ZhichengShashi reach were 0.152,0.0012,and 0.0005,respectively,and the coarse sediment recovered up to the maximum sediment concentration of 0.138 kg/m3over a distance of 15 km;and(iii)the results of the new formula that can consider the effect of bed material composition are in general agreement with the field observations,and the spatial and temporal delay effects are inversely related to particle size and ***,the BMC effect on the nonequilibrium sediment transport in different reaches of the MYR needs to be considered for higher simulation accuracy.

关键词： non-equilibrium sediment transport bed material composition transition probability recovery factor Middle Yangtze River

Additive Hazards Regression with Random Effects for Clustered Failure Times

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Acta Mathematica Sinica,English Series 2015年第3期31卷 511-525页

作者： deng PAN Yan Yan LIU Yuan shan WU Department of Statistics Chinese University of Hong Kong School of Mathematics and Statistics Wuhan University

Additive hazards model with random effects is proposed for modelling the correlated failure time data when focus is on comparing the failure times within clusters and on estimating the correlation between failure times from the same cluster, as well as the marginal regression parameters. Our model features that, when marginalized over the random effect variable, it still enjoys the structure of the additive hazards model. We develop the estimating equations for inferring the regression parameters. The proposed estimators are shown to be consistent and asymptotically normal under appropriate regularity conditions. Furthermore, the estimator of the baseline hazards function is proposed and its asymptotic properties are also established. We propose a class of diagnostic methods to assess the overall fitting adequacy of the additive hazards model with random effects. We conduct simulation studies to evaluate the finite sample behaviors of the proposed estimators in various scenarios. Analysis of the Diabetic Retinopathy Study is provided as an illustration for the proposed method.

关键词： Additive hazards regression clustered failure times counting process empirical process,frailty model checking random effects

A Trusted NUMFabric Algorithm for Congestion Price Calculation at the Internet-of-Things Datacenter

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Computer Modeling in Engineering & Sciences 2021年第3期126卷 1203-1216页

作者： shan Chun Xiaolong Chen Guoqiang deng Hao Liu School of Electronics and Information Guangdong Polytechnic Normal UniversityGuangzhou510665China Information Engineering College Jinhua PolytechnicJinhua32100China The Information Network Engineering and Research Center South China University of TechnologyGuangzhou510641China Qianxin Technology Group Co. Ltd.Beijing100044China

The important issues of network TCP congestion control are how to compute the link price according to the link status and regulate the data sending rate based on link congestion pricing feedback ***,it is difficult to predict the congestion state of the link-end accurately at the *** this paper,we presented an improved NUMFabric algorithm for calculating the overall congestion *** the proposed scheme,the whole network structure had been obtained by the central control server in the Software Defined Network,and a kind of dual-hierarchy algorithm for calculating overall network congestion price had been *** this scheme,the first hierarchy algorithm was set up in a central control server like Opendaylight and the guiding parameter B is obtained based on the intelligent data of global link state *** on the historical data,the congestion state of the network and the guiding parameter B is accurately predicted by the machine learning *** second hierarchy algorithm was installed in the Openflow link and the link price was calculated based on guiding parameter B given by the first *** evaluate this evolved NUMFabric algorithm in NS3,which demonstrated that the proposed NUMFabric algorithm could efficiently increase the link bandwidth utilization of cloud computing IoT datacenters.

关键词： Internet of Things cloud computing intelligent data aggregation distributed optimization trusted network calculation

The X-factor: Enhanced β-oxidation on intracellular triacylglycerols enabling overproduction of polyketide drug-like molecules in microorganisms

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Synthetic and Systems Biotechnology 2020年第1期5卷 19-20页

作者： shan Wang Hai deng Department of Chemistry University of AberdeenAberdeenScotlandAB243UEUnited Kingdom

Natural products have been an unprecedented starting point for drug and agrochemical *** represent the only validated source of chemical diversity capable of delivering a sustainable pipeline for novel drug *** of 1990,80%of clinically used drugs were natural products or natural product-inspired or semi-synthetic *** 1994 to 2007,almost half of the new chemical entities approved by FDA were based on natural products[1].By the end of 2013,natural products or their inspired compounds comprised about 40%of the FDA approved drugs[2].Streptomyces are by far the most prolific natural product producing organisms and as such this genus has been the research subjects for lead compound discovery for decades.

关键词： drugs starting approved

Change of water use efficiency and its relation with root system growth in wheat evolution

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Chinese Science Bulletin 2002年第22期47卷 1879-1883页

作者： ZHANG Suiqi shan Lun deng Xiping Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water ResourcesNorthwest Sci-Tech University of Agriculture and ForestryState Key Lab.of Soil Erosion and Dryland Farming on Loess PlateauYangling 712100China

Raising crop water use efficiency (WUE) is the physiological basis to implement crop high efficiently using water. The present soil column and field experiments are designed to investigate the change of wheat WUE (Triticum aestivum L.) at whole plant level and root system growth in evolution and the relationship between WUE and its root system growth using 10 wheat evolution genotypes with different ploidy chromosomes sets. Results show that in wheat evolution from 2n→6n, WUE at whole plant level increases with the increase of ploidy chromosomes, and root system growth (root weight, root length) and root/shoot ratio of wheat decrease with the increase of ploidy chromosomes under dry and irrigated conditions. WUE is negatively correlated with root weight and root/shoot ratio of wheat in evolution, significantly. Root system growth has an adverse redundancy for WUE in wheat evolution, and the root redundancy reduces with the increase of ploidy chromosomes, which result in the increase of wheat WUE at

关键词： winter wheat evolution root system growth water use efficiency.

LOOKNoC: a low-loss, non-blocking, scalable passive optical interconnect network-on-chip architecture

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The Journal of China Universities of Posts and Telecommunications 2021年第1期28卷 94-106页

作者： deng Junyong Wu Haoyue Luo Jiaying shan Rui Liu Xinchuang School of Eltronie and Information Enginering Xian Universily of Posts and TelecommunicaionsXian 710121China

Low-loss, non-blocking, scalable passive optical interconnect network on-chip(LOOKNoC) structure was proposed based on 2×2 optical exchange switches, using wavelength division multiplexing(WDM)technology to expand to 8×8, 16×16, 32×32, 64×64 passive optical interconnection networks, which can achieve non-blocking communication. The experimental results show that based on the 16×16 optical interconnection network structure, the number of microring resonators(MRs) in LOOKNoC was reduced by 90.9%, 90.9%, 20.0% and 75.0% compared with the generic wavelength-routed optical router(GWOR), λ-router, topology and CrossBar structure. By testing the performance parameters based on the structure of 16×16 by the OMNET++ platform, as the result shows, the average insertion loss of LOOKNoC is 3.0%, 11.6%, 4.8% and 16.7% less than that of GWOR, λ-router, Mesh, and CrossBar structures.

关键词： network-on-chip passive optical interconnect wavelength division multiplexing low-loss non-blocking scalable