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The total flow control equations and the characteristics of unsteady gradually varied flow in open channels

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Journal of Hydrodynamics 2019年第1期31卷 177-185页

作者： shi-he Liu Qian-yi Zhao qiu-shi Luo State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China Yellow River Engineering Consulting Co. LtdZhengzhou 450003China

Most unsteady channel flows in nature and practical engineering appear as gradually varied ones,and in the free surface,the deformation conforms to the long wave ***-dimensional total flow models were usually used to for the numerical simulation of long-term and long-distance reaches to describe the water movements,however,the models lack a clear relationship between the three-dimensional flow field and the total flow ***,few studies of the variations of the roughness coefficient against the time in unsteady flows were *** following results are obtained through the theoretical analysis and the numerical simulations in this paper.(1) One-dimensional total flow control equations of the unsteady gradually varied flow in open channels are obtained directly from the mathematical model of the viscous fluid motion,and can both reflect the influence of the turbulence and provide an explicit expression of the energy slope *** equations establish a direct connection between the descriptions of the three-dimensional flow fields and the one-dimensional total flows.(2) Synchronous prototype observation data and planar two-dimensional numerical simulation results are used to extract the one-dimensional total flow information and discuss the total flow characteristics.(3)The orders of magnitude for terms in the total flow motion equation are compared,and the variation of the roughness coefficient against the time is analyzed.

关键词： Open channel unsteady flow total flow characteristics control equations

SIMULATION OF LOW-CONCENTRATION SEDIMENT-LADEN FLOW BASED ON TWO-PHASE FLOW THEORY

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Journal of Hydrodynamics 2007年第5期19卷 653-660页

作者： LIU shi-he ZHAO shi-lai LUO qiu-shi School of Water Resource and Hydropower Wuhan University Wuhan 430072 China

Low concentration sediment-laden flow is usually involved in water conservancy, environmental protection, navigation and so on. In this article, a mathematical model for low-concentration sediment-laden flow was suggested based on the two-phase flow theory, and a solving scheme for the mathematical model in curvilinear grids was worked out. The observed data in the Zhang River in China was used for the ver/fication of the model, and the calculated results of the water level, velocity and river bed deformation are in agreement with the observed ones.

关键词： two-phase flow sediment-laden flow,numerical simulation

NUMERICAL SIMULATION OF ATOMIZATION RAINFALL AND THE GENERATED FLOW ON A SLOPE

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Journal of Hydrodynamics 2012年第2期24卷 273-279页

作者： LIU shi-he TAI Wei FAN Min LUO qiu-shi State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University Wuhan430072 China Yellow River Engineering Consulting Co. Ltd Zhengzhou 450003 China

This article studies the atomization rainfall and the generated flow on a slope by numerical *** atomization rainfall is simulated by a unified model for splash droplets and a suspended mist,and the distribution of the diameter of splash rain drops is *** slope runoff generated by the atomization rainfall is simulated by a depth-averaged 2-D model,and the localization of the rainfall intensity in space is specially *** simulation results show that：（1） the median rain size of the atomization rainfall increases in the longitudinal direction at first,then monotonously decreases,and the maximum value is taken at the longitudinal position not in consistent with the position where the maximum rain intensity is *** the lateral direction the median rain size monotonously decreases,（2） since the atomization rainfall is distributed in a strongly localized area,it takes a longer time for its runoff yield to reach a steady state than that in the natural rainfall,the variation ranges of the water depth and the velocity in the longitudinal and lateral directions are larger than those in the natural rainfall.

关键词： atomized flow unified model slope runoff numerical simulation

An Edge Computing Algorithm Based on Multi-Level Star Sensor Cloud

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Computer Modeling in Engineering & Sciences 2023年第8期136卷 1643-1659页

作者： Siyu Ren shi qiu Keyang Cheng The Open University of Chengdu Major in Computer ApplicationChengdu610000China Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences.Xi’an710119China School of Computer Science and Communication Engineering Jiangsu UniversityZhenjiang212013China

Star sensors are an important means of autonomous navigation and access to space information for *** have been widely deployed in the aerospace *** satisfy the requirements for high resolution,timeliness,and confidentiality of star images,we propose an edge computing algorithm based on the star sensor *** sensors cooperate with each other to forma sensor cloud,which in turn extends the performance of a single *** research on the data obtained by the star sensor has very important research and application ***,a star point extraction model is proposed based on the fuzzy set model by analyzing the star image composition,which can reduce the amount of data ***,a mappingmodel between content and space is constructed to achieve low-rank image representation and efficient ***,the data collected by the wireless sensor is delivered to the edge server,and a differentmethod is used to achieve privacy *** a small amount of core data is stored in edge servers and local servers,and other data is transmitted to the *** show that the proposed algorithm can effectively reduce the cost of communication and storage,and has strong privacy.

关键词： Star-sensing sensor cloud fuzzy set edge computing mapping

Representation Theorem for Generators of Quadratic BSDEs

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Acta Mathematicae Applicatae Sinica 2018年第3期34卷 622-635页

作者： shi-qiu ZHENG Shou-mei LI College of Applied Sciences Beijing University of Technology Beijing 100124 China College of Sciences North China University of Science and TechnologyTangshan 063210 China

In this paper, we establish a general representation theorem for generator of backward stochastic differential equation（BSDE）, whose generator has a quadratic growth in z. As some applications, we obtain a general converse comparison theorem of such quadratic BSDEs and uniqueness theorem, translation invariance for quadratic g-expectation.

关键词： backward stochastic differential equation representation theorem of generator converse comparison theorem g-expectation

SIMULATION OF SEDIMENT-LADEN FLOW BY DEPTH-AVERAGED MODEL BASED ON UNSTRUCTURED COLLOCATED GRID

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Journal of Hydrodynamics 2007年第4期19卷 525-532页

作者： LIU shi-he LUO qiu-shi MEI Jun-ya School of Water Resource and Hydropower Wuhan University Wuhan 430072 China

The 2-D depth-averaged mathematical model for sediment-laden flows has been widely used in river control and other related engineering problems, and now it is usually solved on structured grids. Since the natural river is usually very complicated in plane boundary, and unstructured grids are more attractive in solving the problems with complicated domains, the following questions about solving 2-D depth-averaged model were discussed in this article：（1） a modified Bowyer algorithm was suggested to generate unstructured grids for natural rivers, （2） the Finite Volume Method （FVM） is employed to discretize the governing equations of the 2-D depth-averaged model and an implicit scheme was suggested with unstructured collocated grids, （3） the observed hydrological data of the Chenglingji Reach in the Yangtze River are used for verification of the presented method It seems that the suggested numerical scheme works very well, and the simulation results of both hydraulic characteristics and river bed deformation are in good agreement with the observed ones.

关键词： Bowyer algorithm unstructured grid SIMPLE algorithm

Satellite anomaly detection based on reconstruction discrepancy theory utilizing a new dual-branch reconstruction model

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Science China(Technological Sciences) 2024年第10期67卷 3294-3307页

作者： ZHAO HaoTian qiu shi LIU Ming CAO XiBin Research Center of Satellite Technology School of AstronauticsHarbin Institute of TechnologyHarbin 150001China

To enhance the accuracy of deep learning methods based on reconstruction discrepancy in satellite anomaly detection tasks,this study proposes a dual-branch reconstruction model(DBRM)and designs a comprehensive satellite anomaly detection framework around this ***,we introduce the temporal-channel mixer(TC-Mixer)module,which mainly comprises a self-attention layer for capturing long-range temporal dependencies in telemetry data,and two types of feed-forward networks(FFN)for extract-ing complex patterns in the temporal and channel dimension of telemetry *** design endows the TC-Mixer module with robust capabilities for extracting complicated dependencies in telemetry ***,with the TC-Mixer module as the main component,we designed the *** model utilizes a shared latent representation layer,allowing the regeneration branch and forecasting branch of the DBRM to share most of the feature extraction network *** approach significantly en-hances the model’s regression accuracy while reducing computational ***,using the DBRM as the core network model,we devised a comprehensive satellite anomaly detection *** includes an anomaly criterion that considers the reconstruction discrepancy of both the regeneration and forecasting branches,the peak-over-threshold(POT)method for anomaly thresholding,and the MIC-based feature engineering method,***,we conducted comparative experiments with several SOTA anomaly detection algorithms on two public and one private satellite anomaly detection *** experimental results validate the effectiveness and superiority of our proposed method.

关键词： anomaly detection reconstruction discrepancy dual-branch reconstruction model(DBRM) satellite telemetry data time series

Lung Nodules Detection in CT Images Using Gestalt-Based Algorithm

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Chinese Journal of Electronics 2016年第4期25卷 711-718页

作者： qiu shi WEN Desheng CUI Ying FENG Jun Xi'an Institute of Optics and Precision Mechanics of CAS University of Chinese Academy of Sciences College of Equipment Engineering Engineering University of Chinese Armed Police Force School of Information Science and Technology Northwest University

To overcome low accuracy and high false positive of existing computer-aided lung nodules *** propose a novel lung nodule detection scheme based on the Gestalt visual cognition *** proposed scheme involves two parts which simulate human eyes cognition features such as simplicity,integrity and ***,lung region was segmented from lung Computed tomography(CT) *** local threedimensional information was integrated into the Maximum intensity pro jection(MIP) images from axial,coronal and sagittal *** this way,lung nodules and vascular are strengthened and discriminated based on pathologic image characteristics of lung *** experimental database includes fifty-three high resolution CT images contained lung nodules,which had been confirmed by *** experimental results show that,the accuracy rate of the proposed algorithm achieves 91.29%.The proposed framework improves performance and computation speed for computer aided nodules detection.

关键词： Computer-aided detection(CAD) Lung nodules Maximum intensity pro jection(MIP)

Dynamics of nuclear spin-1/2 system in a strong bichromatic RF-field

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Nuclear Science and Techniques 2009年第1期20卷 56-59页

作者： LU Hongliang shi Chunhua qiu Xijun Department of Physics Shanghai University Shanghai 200444 China

Based on calculating the influence of RF-field with various physical parameters on the dynamics of the spin 1/2 system,it was found that the spin state could be changed up and down by choosing appropriate RF pulses, and the coherent control of the RF pulses could substantially modify the behavior of spin dynamics:quicker change of two states could be produced even for small pulse *** addition,the oscillatory structures around the resonant frequency and the propagation features of the pulses depend on the relative phase of the bichromatic RF pulses.

关键词：原子能核四极矩共振探测原理试验