检索结果-南通市图书馆

Optimal Risk Sharing for Maxmin Choquet Expected Utility Model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第2期40卷 430-444页

作者： De-jian tian Shang-ri wu School of Mathematics China University of Mining and TechnologyXuzhou 221116China

This article analyzes the Pareto optimal allocations,agreeable trades and agreeable bets under the maxmin Choquet expected utility(MCEU)*** provide several useful characterizations for Pareto optimal allocations for risk averse *** derive the formulation descriptions for non-existence agreeable trades or agreeable bets for risk neutral *** build some relationships between ex-ante stage and interim stage on agreeable trades or bets when new information arrives.

关键词： maxmin Choquet expected utility model Pareto optimal allocation agreeable trade agreeable bet

TWO-PHASE IMAGE SEGMENTATION BY NONCONVEX NONSMOOTH MODELS WITH CONVERGENT ALTERNATING MINIMIZATION ALGORITHMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2023年第4期41卷 588-622页

作者： Weina Wang Nannan tian Chunlin wu Department of Mathematics Hangzhou Dianzi UniversityHangzhou 310018China School of Mathematical Sciences Nankai UniversityTianjin 300000China

Two-phase image segmentation is a fundamental task to partition an image into foreground and *** this paper,two types of nonconvex and nonsmooth regularization models are proposed for basic two-phase *** extend the convex regularization on the characteristic function on the image domain to the nonconvex case,which are able to better obtain piecewise constant regions with neat *** analyzing the proposed non-Lipschitz model,we combine the proximal alternating minimization framework with support shrinkage and linearization strategies to design our *** leads to two alternating strongly convex subproblems which can be easily ***,we present an algorithm without support shrinkage operation for the nonconvex Lipschitz *** the Kurdyka-Lojasiewicz property of the objective function,we prove that the limit point of the generated sequence is a critical point of the original nonconvex nonsmooth *** experiments and comparisons illustrate the effectiveness of our method in two-phase image segmentation.

关键词： Nonconvex nonsmooth regularization Characteristic function Box constraints Support shrinking alternating minimization Kurdyka-Lojasiewicz property Image segmentation

Memristor-based multi-channel pulse coupled neural network for image fusion

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2020年第6期27卷 54-72页

作者： Liu Jian wu Chengmao tian Xiaoping School of Electronic Engineering Xi'an University of Posts and TelecommunicationsXi'an 710121China

Image fusion is widely used in computer vision and image *** that the traditional image fusion algorithm has a certain limitation in multi-channel image fusion,a memristor-based multi-channel pulse coupled neural network(M-MPCNN)for image fusion is *** on a dual-channel pulse coupled neural network(D-PCNN),a novel multi-channel pulse coupled neural network(M-PCNN)is firstly constructed in this *** the exponential growth dynamic threshold model is used to improve the pulse generation of pulse coupled neural network,which can not only avoid multiple ignitions effectively,but can also improve operational efficiency and reduce *** the same time,synchronous capture can also enhance image edge,which is more conducive to image ***,the threshold and synaptic characteristics of pulse coupled neural networks(PCNNs)can be well realized by using a memristor-based pulse *** results show that the proposed algorithm can fuse multi-source images more effectively than existing state-of-the-art fusion algorithms.

关键词： multi-channel memristor pulse coupled neural network

The effect of dolomite amendment on soil organic carbon mineralization is determined by the dolomite size

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2021年第1期10卷 118-129页

作者： hongtao wu Jinli Hu Muhammad Shaaban Peng Xu Jinsong Zhao Ronggui Hu College of Urban and Environmental Sciences Hubei Normal UniversityHuangshiChina College of Resources and Environment Huazhong Agricultural UniversityWuhanChina Department of Soil Science Faculty of Agricultural Sciences and TechnologyBahauddin Zakariya UniversityMultanPakistan.

Background:The size of lime material is vital for the efficiency of ameliorating soil acidity,thereby influencing soil biochemical ***,the effects of different sized lime material application on soil organic carbon(SOC)mineralization are yet to be ***,a 35-day incubation experiment was conducted to determine the effects of three particle size fractions(0.5 to 0.25,0.25 to 0.15,and<0.15 mm)of dolomite on SOC mineralization of two acidic paddy ***:CO_(2) emission was increased by 3–7%,11–21%,and 32–49%for coarse-,medium-,and fine-sized dolomite treatments,respectively,compared to the control in both *** also well conformed to a first-order model in all treatments,and the estimated decomposition rate constant was significantly higher in the fine-sized treatment than that of other treatments(P<0.05),indicating that SOC turnover rate was dependent on the dolomite *** finer particle sizes were characterized with higher efficiencies of modifying soil pH,consequently resulting in higher dissolved organic carbon contents and microbial biomass carbon,eventually leading to higher CO_(2) ***:The results demonstrate that the size of dolomite is a key factor in regulating SOC mineralization in acidic paddy soils when dolomite is applied to manipulate soil pH.

关键词： Dolomite Particle size SOC mineralization Acidic paddy soil

Radar Quantitative Precipitation Estimation Based on the Gated Recurrent Unit Neural Network and Echo-Top Data

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2023年第6期40卷 1043-1057页

作者： Haibo ZOU Shanshan wu Miaoxia tian Key Laboratory of Poyang Lake Wetland and Watershed Research of Ministry of Education&School of Geography and Environmental Science Jiangxi Normal UniversityNanchang 330022China Meteorological Sciences Institute of Jiangxi Province Nanchang 330046China Key Laboratory of Natural Disaster Monitoring Early Warning and Assessment of Jiangxi ProvinceNanchang 330022China Jiangxi Climate Center Nanchang 330046China

The Gated Recurrent Unit(GRU) neural network has great potential in estimating and predicting a variable. In addition to radar reflectivity(Z), radar echo-top height(ET) is also a good indicator of rainfall rate(R). In this study, we propose a new method, GRU_Z-ET, by introducing Z and ET as two independent variables into the GRU neural network to conduct the quantitative single-polarization radar precipitation estimation. The performance of GRU_Z-ET is compared with that of the other three methods in three heavy rainfall cases in China during 2018, namely, the traditional Z-R relationship(Z=300R1.4), the optimal Z-R relationship(Z=79R1.68) and the GRU neural network with only Z as the independent input variable(GRU_Z). The results indicate that the GRU_Z-ET performs the best, while the traditional Z-R relationship performs the worst. The performances of the rest two methods are *** further evaluate the performance of the GRU_Z-ET, 200 rainfall events with 21882 total samples during May–July of 2018 are used for statistical analysis. Results demonstrate that the spatial correlation coefficients, threat scores and probability of detection between the observed and estimated precipitation are the largest for the GRU_Z-ET and the smallest for the traditional Z-R relationship, and the root mean square error is just the opposite. In addition, these statistics of GRU_Z are similar to those of optimal Z-R relationship. Thus, it can be concluded that the performance of the GRU_ZET is the best in the four methods for the quantitative precipitation estimation.

关键词： quantitative precipitation estimation Gated Recurrent Unit neural network Z-R relationship echo-top height

Experimental Study of Turbulent Boundary Layers on Groove/Smooth Flat Surfaces

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2005年第3期14卷 193-197页

作者： Hongwei MA Qiao tian Hui wu School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100083 China

This paper presents an experimental investigation of the turbulent boundary layers on both groove and smooth flat surfaces. The flow structures were shown in a water tunnel using the hydrogen-bubble flow visualization technique. The measurement results indicate that: (1) the grooves can effectively reduce accumulation of low-speed fluids, decrease the number of the low-speed streaks and depress oscillation of the streaks in the sublayer; (2) the grooves can restrain forming of the horseshoe vortices in the buffer region; (3) the grooves bate oscillation and kinking of the quasi-streamwise vortices and restrain production of the hairpin vortices and the ring vortices, reducing both frequency and intensity of the turbulence bursting; (4) the grooves directly affect the flow structures in the sublayer of the boundary layer and then modulate the flow field up to the buffer region and the logarithmic region by restraining development and interaction of the vortices.

关键词： streamwise groove turbulent boundary layer drag reduction mechanism coherent structure hydrogen-bubble flow visualization

A New Coherent Integration Method for Frequency Jittering Radar

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Electronics 2017年第5期26卷 1008-1016页

作者： YANG Gang tian Jing wu Shuang CUI Wei wu Siliang School of Information and Electronics Beijing Institute of Technology Beijing Institute of Remote Sensing Equipment

For the frequency jittering radar,the problems of range migration and phase jittering among different pulses may occur during the long-time integration,which will affect the target energy ***,a new coherent integration algorithm,namely,Frequency jittering based Radon-Fourier transform(FJ-RFT),is *** on jointly searching in the motion parameter space,the problems mentioned above can be simultaneously resolved and the coherent integration can be then *** Cramer-Rao lower bound(CRLB) and the Blind speed sidelobes(BSSL) of the proposed FJ-RFT are analyzed in ***,numerical experiments are provided to demonstrate the effectiveness of the proposed method.

关键词： Frequency jittering Coherent integration Cramer-Rao lower bound(CRLB) Blind speed sidelobes(BSSL)

A video structural similarity quality metric based on a joint spatial-temporal visual attention model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第12期10卷 1696-1704页

作者： Hua ZHANG Xiang tian Yao-wu CHEN Institute of Advanced Digital Technology and Instrumentation Zhejiang University Hangzhou 310027 China

Objective video quality assessment plays a very important role in multimedia signal processing. Several extensions of the structural similarity （SSIM） index could not predict the quality of the video sequence effectively. In this paper we propose a structural similarity quality metric for videos based on a spatial-temporal visual attention model. This model acquires the motion attended region and the distortion attended region by computing the motion features and the distortion contrast. It mimics the visual attention shifting between the two attended regions and takes the burst of error into account by introducing the non-linear weighting fimctions to give a much higher weighting factor to the extremely damaged frames. The proposed metric based on the model renders the final object quality rating of the whole video sequence and is validated using the 50 Hz video sequences of Video Quality Experts Group Phase I test database.

关键词： Quality assessment Structural similarity (SSIM) index Attended region Visual attention shift

Particulate n-alkanes and fatty acids in the Changjiang river system

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2007年第2期26卷 36-48页

作者： wu Ying ZHANG Jing LIU Sumei ZHANG Zaifeng CHEN hongtao XIONG Hui State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai 200062 China College of Chemical Engineering and Chemistry Ocean University of China Qingdao 266003 China Nantong Institute of Environmental Sciences Nantong 314151 China

Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease （0.84% ～ 1.88%） of organic carbon content from the upper reaches to the estuary.δ^13 values of particulate organic carbon was in the range of -24.9×10^-3 to -26.6×10^-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm^3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm^3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ^13 and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs （soil organic matter） among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream.

关键词： organic carbon δ13C n-alkanes fatty acids Changjiang River