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PREDICTION OF STAGE-DISCHARGE IN RIVER USING KALMAN FILTER

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Journal of Hydrodynamics 1991年第1期3卷 51-55页

作者： fan, Yu-chen Water Conservancy and Hydropower Research Inst Beijing China

In this paper Mannig's resistance coefficient n is used as a state-variable for Kalman filter, the stage h in the river as an observation-variable. Comparing this form of Kalman filter with Simons' form, the result of... 详细信息

关键词： Computers Applications Flow of Water Hydrodynamics Mathematical Models Mathematical Techniques Differential Equations

Large Deviation Results for Generalized Compound Negative Binomial Risk Models

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Acta Mathematicae Applicatae Sinica 2009年第1期25卷 151-158页

作者： fan-chao Kong chen Shen School of Mathematics Anhui University and Hefei Teachers College Hefei 230001 China

In this paper we extend and improve some results of the large deviation for random sums of random variables. Let {Xn;n 〉 1} be a sequence of non-negative, independent and identically distributed random variables with common heavy-tailed distribution function F and finite mean μ ∈R^＋, {N（n）; n ≥0} be a sequence of negative binomial distributed random variables with a parameter p C （0, 1）, n ≥ 0, let {M（n）; n ≥ 0} be a Poisson process with intensity λ 〉 0. Suppose {N（n）; n ≥ 0}, {Xn; n≥1} and {M（n）; n ≥ 0} are mutually independent. Write S（n） =N（n）∑i=1 Xi-cM（n）.Under the assumption F ∈ C, we prove some large deviation results. These results can be applied to certain problems in insurance and finance.

关键词： Poisson process negative binomial sequence large deviation heavy-tailed distribution ruinprobabili

Thermomechanical coupling effect on characteristics of oxide film during ultrasonic vibration-assisted ELID grinding ZTA ceramics

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Chinese Journal of Aeronautics 2021年第6期34卷 125-140页

作者： fan chen Guangxi LI Bo ZHAO Wenbo BIE School of Electrical and Mechanical Engineering Pingdingshan UniversityPingdingshan 467000China School of Mechanical and Power Engineering Henan Polytechnic UniversityJiaozuo 454003China

Ultrasonic vibration-assisted ELID(UVA-ELID)grinding is utilized as a novel and highly efficient processing method for hard and brittle materials such as *** this study,the UVA-ELID grinding ZTA ceramics is employed to investigate the influence of thermomechanical loading on the characteristics of oxide *** on the fracture mechanics of material,the model of internal stress for oxide film damage is *** thermomechanical loading is composed of mechanical force and the thermal stress generating from grinding *** theoretical model is established for the mechanical force,thermal stress and internal stress *** the finite element analysis method is used to simulate the theoretical *** mechanical force and grinding temperature is measured during the actual grinding *** the grinding process,the effect of grinding wheel speed and grinding depth on the thermomechanical force and the characteristics of oxide film is *** with the conventional ELID(CELID)grinding,the mechanical force decreased by 25.6%and 22.4%with the increase of grinding wheel speed and grinding depth respectively,and the grinding temperature declined by 10.7%and12.8%during the UVA-ELID *** thermal stress in the latter decreased by 16.3%and20.8%respectively,and internal stress reduced by 12.3%and 15.6%.It was experimentally found that the topographies of oxide layer on the surface of the wheel and the machined surface in the latter was better than that in the *** results indicate that the action of ultrasonic vibration establish a significant effect on the ***,it should be well considered for future reference when processing the ZTA ceramics.

关键词： Oxide film Surface quality Thermomechanical loading Ultrasonic vibration-assisted ELID grinding ZTA ceramics

Theoretical Study on Mechanism of Reaction of OH with HO2NO2

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Chinese Journal of Chemical Physics 2008年第1期21卷 32-38页

作者： Yan Tian Tian-jing He Li He fan-chen Liu Dong-ming chen Department of Chemical Physics University of Science and Technology of China Hefei 230026 China Department of Electronic Science and Technology University of Science and Technology of ChinaHefei 230025 China School of Science Anhui Agricultural University Hefei 230036 China

The reaction of HO2NO2 （peroxynitric acid, PNA） with OH was studied by the hybrid density functional B3LYP and CBS-QB3 methods. Based on the calculated potential energy surface, five reaction channels, H20＋NO2＋O2, HOOH＋NO3, NO2＋HO3H, HO2＋HONO2 and HO2＋HOONO, were examined in detail. The major reaction channel is PNA＋OH→M1→TS1→H2O＋NO2＋O2. Taking a pre-equilibrium approximation and using the CBS-QB3 energies, the theoretical rate constant of this channel was calculated as 1.13×10-12 cm^3/（molecule s） at 300 K, in agreement with the experimental result. Comparison between reactions of HOONO2＋OH and HONO2＋OH was carried out. For HOR＋OH reactions, the total rate constants increase from R=NO2 to R=ONO2, which is consistent with experimental measurements.

关键词： Reaction Peroxynitric acid ab initio calculation Rate constant

A density functional study on magnetic exchange interaction between Mn(II)ion and nitronyl nitroxide radical in trans-and cis-metal-radical complexes

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Science China Chemistry 2005年第5期48卷 402-414页

作者： WEI Haiyan WANG fan chen Zhida State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China State Key Laboratory of Rare Earth Materials Chemistry and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China

The magneto-structural correlation between a Mn(II) ion, coordinated in an octahe-dral environment, and two nitronyl nitroxide radical ligands in trans- and cis-metal-radical com-plexes is investigated by the broken symmetry (BS) approach within density functional theory (DFT). The dependences of coupling constants J on three structural parameters: (i) bond angle θ (Mn-O-N (nitroxide)); (ii) rotating angle ψ, defined by the nitronyl nitroxide radical plane rotating around the axial Mn-O (nitroxide); (iii) bond distance R (Mn-O (nitroxide)) are directly calculated. Our calculations showed that both trans- and cis-Mn(II)-radical complexes behave a stronger antiferromagnetic interaction, consistent with experiments. In view of molecular orbital theory, the direct exchanges, including σ-type and π-type exchanges, are responsible for the magnetic ex-change pathways. There is a preferable linear correlation between the calculated coupling con-stants J and the overlap integral squares Sa2b between the local magnetic orbitals at the various rotating angle ψ at the fixed bond angle θ and bond distance R, in both trans- and cis-Mn(II)- radical complexes.

关键词： density functional theory, broken-symmetry approach, magnetic exchange, molecular magnetism,Mn(II)-NITR complex.

Pulling Vs. Pushing:Effect of Climatic Factors on Periodical Fluctuation of Russian and South Korean Tourist Demand in Hainan Island,China

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Chinese Geographical Science 2017年第4期27卷 648-659页

作者： chen fan LIU Jun GE Quansheng Tourism School Sichuan University Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences

While climate is an important factor attracting tourists to certain destinations,it can also motivate people residing in a country with a harsh climate to move to another *** applying X-12 decompositions and a panel data regression analysis,this study analyzes the pull and push effects of climatic seasonal factors between destination(Hainan Island,China) and source countries(Russia and South Korea).The findings show that climatic seasonal factors have significant pulling and pushing effects on seasonal patterns of tourism demand,with temperature being the main ***,the number of paid vacation days in the source country affects that country's sensitivity to climatic seasonal factors;countries with a higher numbers of paid vacation days are more sensitive to climatic ***,future global warming may causes the aforementioned pull and push effects to abate,which will have an unavoidable influence on tourism industries.

关键词： seasonality climate tourism demand Hainan Island China

A study on specialist or special disease clinics based on big data

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Frontiers of Medicine 2014年第3期8卷 376-381页

作者： Zhuyuan fang Xiaowei fan Gong chen Jiangsu Province Ho spital of TCM Nanjing 210029 China

Correlation analysis and processing of massive medical information can be implemented through big data technology to find the relevance of different factors in the life cycle of a disease and to provide the basis for scientific research and clinical practice. This paper explores the concept of constructing a big medical data platform and introduces the clinical model construction. Medical data can be collected and consolidated by distributed computing technology. Through analysis technology, such as artificial neural network and grey model, a medical model can be built. Big data analysis, such as Hadoop, can be used to construct early prediction and intervention models as well as clinical decision-making model for specialist and special disease clinics. It establishes a new model for common clinical research for specialist and special disease clinics.

关键词： big data correlation analysis medical information integration data analysis clinical model

High efficient moving object extraction and classification in traffic video surveillance

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Journal of Systems Engineering and Electronics 2009年第4期20卷 858-868页

作者： Li Zhihua Zhou fan Tian Xiang chen Yaowu Inst. of Advanced Digital Technology and Instrument Zhejiang Univ. Hangzhou 310027 P. R. China

Moving object extraction and classification are important problems in automated video surveillance systems. A background model based on region segmentation is proposed. An adaptive single Gaussian background model is used in the stable region with gradual changes, and a nonparametric model is used in the variable region with jumping changes. A generalized agglomerative scheme is used to merge the pixels in the variable region and fill in the small interspaces. A two-threshold sequential algorithmic scheme is used to group the background samples of the variable region into distinct Gaussian distributions to accelerate the kernel density computation speed of the nonparametric model. In the feature-based object classification phase, the surveillance scene is first partitioned according to the road boundaries of different traffic directions and then re-segmented according to their scene localities. The method improves the discriminability of the features in each partition. AdaBoost method is applied to evaluate the relative importance of the features in each partition respectively and distinguish whether an object is a vehicle, a single human, a human group, or a bike. Experimental results show that the proposed method achieves higher performance in comparison with the existing method.

关键词： background model nonparametric model adaptive single Gaussian model object classification

Factorial design analytics on effects of material parameter uncertainties in multiphysics modeling of additive manufacturing

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npj Computational Materials 2023年第1期9卷 1848-1865页

作者： Amanda Giam fan chen Jiaxiang Cai Wentao Yan Integrative Sciences and Engineering Programme NUS Graduate SchoolNational University of SingaporeSingapore 119077Singapore Department of Mechanical Engineering National University of SingaporeSingapore 117575Singapore Department of Industrial Systems Engineering and Management National University of SingaporeSingapore 117576Singapore

A bottleneck in Laser Powder Bed Fusion(L-PBF)metal additive manufacturing(AM)is the quality inconsistency of its *** address this issue without costly experimentation,computational multi-physics modeling has been used,but the effectiveness is limited by parameter uncertainties and their *** propose a full factorial design and variable selection approach for the analytics of main and interaction effects arising from material parameter uncertainties in multi-physics *** is collected from high-fidelity thermal-fluid simulations based on a 2-level full factorial design for 5 selected material *** physical phenomena of the L-PBF process are analyzed to extract physics-based domain knowledge,which are used to establish a validation checkpoint for our *** data visualization with half-normal probability plots,interaction plots and standard deviation plots,is used to assess if the checkpoint is being *** then apply the combination of best subset selection and the LASSO method on multiple linear regression models for comprehensive variable *** yield statistically and phyiscally validated findings with practical implications,emphasizing the importance of parameter interactions under uncertainty,and their relation to the underlying physics of L-PBF.

关键词： parameter additive analytic