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Reducing feedback load for OFDM-based wireless system

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The Journal of China Universities of Posts and Telecommunications 2013年第2期20卷 25-31页

作者： LI ming-ming WANG Xiao-xiang ZHOU Jia Key Laboratory of Universal Wireless Communications Ministry of Education Beijing University of Posts and Telecommunications

In this paper, the feedback load reduction problem in wireless systems based on orthogonal frequency division multiplexing （OFDM） is investigated and an opportunistic feedback scheme （OFS） is proposed. The key idea behind OFS is that only the key channel gains which can significantly affect the system throughput are fed back to the BS. Firstly, the key channel gains are proved to belong to a channel gain interval. Secondly, a statistical method is proposed to estimate the channel gain interval. Thirdly, the opportunistic feedback scheme is formulated and the feedback load of OFS is analyzed. The advantage of OFS is threefold： the first is OFS can work in both OFDM-based multicast system and OFDM-based unicast system. The second is the channel fading type of the BS-user link is not required, which is more realistic. The third is OFS can get better feedback load performance compared with other schemes, while achieving almost the same throughput performance compared with that of full feedback scheme.

关键词： OFDM wireless system feedback load reduction multicast system unicast system opportunistic feedback scheme

ANALYSIS OF STATE-CHANGING WATER HAMMER IN A LONG PIPE

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Journal of Hydrodynamics 2004年第1期16卷 52-60页

作者： ZHANGLi-xiang ZHANGHong-ming WANGZheng-jun YANGKe DepartmentofEngineeringMechanics KunmingUniversityofScienceandTechnologyKunming650051China YuannanNujiangElectricPowerCorp. Nujiang673100China CollegeofArchitecturalandCivilEngineering WenzhouUniversityWenzhou325027China

Pressure wave propagation along a pipe attached with an activepressure-controlling system at an end was described by an unsteady state-changing motion of thepressure wave fronts, in order to study the interaction among successive waves caused by successivecontrolling spillovers with the consideration of liquid compressibility due to high head. A modelfor water hammer propagation was established by using the continuity, momentum, and energyequations. The influence of the wave interactions on the pressure suppression was analyzed. Testingverifications were conducted with a 2575m length and 776m head penstock in hydro-power station. Thecomputed results are in good agrement with the tested ones.

关键词： water hammer unsteady flows fluid-structure interaction (FSI)

Dynamic optimization of 1,3-propanediol fermentation process:A switched dynamical system approach

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Chinese Journal of Chemical Engineering 2022年第4期35卷 192-204页

作者： xiang Wu Yuzhou Hou Kanjian Zhang ming Cheng School of Mathematical Sciences Guizhou Normal UniversityGuiyang 550001China School of Life Sciences Guizhou Normal UniversityGuiyang 550001China School of Electrical Engineering Southeast UniversityNanjing 210096China School of Automation Southeast UniversityNanjing 210096China Key Laboratory of Measurement and Control of CSE Ministry of EducationSoutheast UniversityNanjing 210096China

This paper considers a dynamic optimization problem(DOP)of 1,3-propanediol fermentation process(1,3-PFP).Our main contributions are as ***,the DOP of 1,3-PFP is modeled as an optimal control problem of switched dynamical *** the existing switched dynamical system optimal control problem,the state-dependent switching method is applied to design the switching ***,in order to obtain the numerical solution,by introducing a discrete-valued function and using a relaxation technique,this problem is transformed into a nonlinear parameter optimization problem(NPOP).Although the gradient-based algorithm is very efficient for solving NPOPs,the existing algorithm is always trapped in a local minimum for such problems with multiple local ***,in order to overcome this challenge,a gradient-based random search algorithm(GRSA)is proposed based on an improved gradient-based algorithm(IGA)and a novel random search algorithm(NRSA),which cannot usually be trapped in a local *** convergence results are also established,and show that the GRSA is globally ***,a DOP of 1,3-PFP is provided to illustrate the effectiveness of the GRSA proposed by this paper.

关键词： Process control Optimization Mathematical modeling Switched system State-dependent switching Global optimization

Orientation-Dependent Morphology and Evolution of Interfacial Dislocation Networks in Ni-Based Single-Crystal Superalloys:A Molecular Dynamics Simulation

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Acta Mechanica Solida Sinica 2021年第1期34卷 79-90页

作者： Bin Chen Wen-Ping Wu ming-xiang Chen Department of Engineering Mechanics School of Civil EngineeringWuhan UniversityWuhan430072China State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan430072China

In this paper,the morphology and evolution of interfacial dislocation networks of(100),(110)and(111)interphases of Ni-based single-crystal superalloys are studied by molecular dynamics(MD)***-dimensional cubic-type and sandwich-type models are chosen to explore the orientation-dependent morphology of dislocation networks,and their respective advantages and disadvantages are *** the simulations,it is observed that various lattice orientations and model types lead to different morphologies of dislocation *** on the analysis of average atomic energy and dislocation characteristics,the(100)orientation model has a more regular dislocation network,lower energy and better stability than the(110)and(111)orientation models after MD relaxation,which are supported by previous experimental and numerical ***,the cubic-type model has lower energy and better stability than the sandwich-type *** will be helpful for choosing a more appropriate and reasonable model for simulating the interfacial dislocation networks of Ni-based single-crystal superalloys.

关键词： Ni-based single-crystal superalloys Molecular dynamics simulation Orientation Interfacial dislocation networks

Predictive Analysis of Susceptibility of Different Species to SARS-CoV-2 based on ACE2 Receptors

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Biomedical and Environmental Sciences 2020年第11期33卷 877-881页

作者： XU Xiao Gang WANG Huan WANG San Ying ZHANG Jing sun Chuan WEI ming xiang YAN Jing MAO Gen xiang Zhejiang Provincial Key Lab of Geriatrics&Geriatrics Institute of Zhejiang Province Department of GeriatricsZhejiang HospitalHangzhou 310013ZhejiangChina The George Washington University Department of BiostatisticsWashington DC 20052USA

Coronavirus Disease 2019(COVID-19)is a pulmonary inflammatory disease caused by infection with the highly pathogenic new coronavirus(SARSCo V-2)[1].To date,COVID-19 has spread to at least210 countries and territories,infected more than10.94 million people,and killed more than 519,000 people,according to Johns Hopkins *** April 15,2020,the COVID-19 outbreak was declared a global health emergency[2].

关键词： ACE2 Hopkins Receptor

How to improve machine learning models for lithofacies identification by practical and novel ensemble strategy and principles

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Petroleum Science 2023年第2期20卷 733-752页

作者： Shao-Qun Dong Yan-ming sun Tao Xu Lian-Bo Zeng xiang-Yi Du Xu Yang Yu Liang State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China College of Science China University of PetroleumBeijing102249China College of Geoscience China University of PetroleumBeijing102249China

Typically, relationship between well logs and lithofacies is complex, which leads to low accuracy of lithofacies identification. Machine learning (ML) methods are often applied to identify lithofacies using logs labelled by rock cores. However, these methods have accuracy limits to some extent. To further improve their accuracies, practical and novel ensemble learning strategy and principles are proposed in this work, which allows geologists not familiar with ML to establish a good ML lithofacies identification model and help geologists familiar with ML further improve accuracy of lithofacies identification. The ensemble learning strategy combines ML methods as sub-classifiers to generate a comprehensive lithofacies identification model, which aims to reduce the variance errors in prediction. Each sub-classifier is trained by randomly sampled labelled data with random features. The novelty of this work lies in the ensemble principles making sub-classifiers just overfitting by algorithm parameter setting and sub-dataset sampling. The principles can help reduce the bias errors in the prediction. Two issues are discussed, videlicet (1) whether only a relatively simple single-classifier method can be as sub-classifiers and how to select proper ML methods as sub-classifiers;(2) whether different kinds of ML methods can be combined as sub-classifiers. If yes, how to determine a proper combination. In order to test the effectiveness of the ensemble strategy and principles for lithofacies identification, different kinds of machine learning algorithms are selected as sub-classifiers, including regular classifiers (LDA, NB, KNN, ID3 tree and CART), kernel method (SVM), and ensemble learning algorithms (RF, AdaBoost, XGBoost and LightGBM). In this work, the experiments used a published dataset of lithofacies from Daniudi gas field (DGF) in Ordes Basin, China. Based on a series of comparisons between ML algorithms and their corresponding ensemble models using the ensemble strat

关键词： Lithofacies identification Machine learning Ensemble learning strategy Ensemble principle Homogeneous ensemble Heterogeneous ensemble

Protein science research in China

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Protein & Cell 2010年第1期1卷 4-5页

作者： ming sun Rui-ming Xu Institute of Biophysics Chinese Academy of Sciences

Proteins are major executors of life processes, carrying out essential and nonessential functions inside and outside of the cell, in species ranging from simple unicellular organisms to mammals. Thus, not surprisingly, studies of structure and function of proteins span the entire spectrum of molecular biology and modern biomedical sciences in general. Due to historical reasons, protein science research in China was isolated and limited in scope until late 1970s. In the last two decades,China has seen an outburst of research activities,government initiatives, and aggregation of human talents in protein science research. This article provides an overview of major initiatives in research funding, investment in infrastructures, and research forces for protein science research in China.

关键词： China science research structure and function molecular biology major government activities processes essential studies species limited simple modern forces scope human span cell two

Influence of Inhomogeneity on Critical Behavior of Earthquake Model on Random Graph

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Communications in Theoretical Physics 2006年第2X期46卷 261-264页

作者： ZHANG Duan-ming sun Fan YU Bo-ming PAN Gui-Jun YIN Yah-Ping LI Rui SU xiang-Ying Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

We consider the earthquake model on a random graph. A detailed analysis of the probability distribution of the size of the avalanches will be given. The model with different inhomogeneities is studied in order to compare the critical behavior of different systems. The results indicate that with the increase of the inhomogeneities, the avalanche exponents reduce, i.e., the different numbers of defects cause different critical behaviors of the system. This is virtually ascribed to the dynamical perturbation.

关键词： self-organized criticality earthquake model critical behavior power-law finite size scaling random network

Integrated Planning of an Active Distribution Network and DG Integration in Clusters Considering a Novel Formulation for Reliability Assessment

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CSEE Journal of Power and Energy Systems 2023年第2期9卷 561-576页

作者： Di Hu Lei sun ming Ding School of Electrical Engineering and Automation Hefei University of TechnologyHefei 230009China Anhui Provincial Laboratory of Renewable Energy Utilization and Energy Saving Hefei University of TechnologyHefei 230009China

The concept of DG clusters is introduced with highly penetrated integration of distributed generation(DG)into active distribution networks(ADNs).DG clusters are referred to as parts of an ADN,including DGs,distribution lines and *** formation of DG clusters helps to optimally dispatch DG outputs within *** this regard,an integrated planning strategy of ADNs and DGs in cluster(IPNDGC)is *** order to guarantee that the planning strategy meets the reliability requirements,a reliability assessment is considered in the proposed ***,reliability assessment is generally accomplished according to a fixed network topology and known DG allocation,which makes it difficult to integrate reliability into planning *** deal with this difficulty,a novel formulation method for reliability assessment is proposed considering the network topology uncertainties and isolated operating probabilities of DG *** reliability index(RI)represented by expected customer interruption cost(ECOST)is employed in the proposed planning *** planning model is formulated as a mixed integer second order conic programming planning *** actual distribution system is employed to illustrate the accuracy and efficiency of the proposed planning model.

关键词： DG cluster distribution network planning reliability