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An improved deep forest model for forecast the outdoor atmospheric corrosion rate of low-alloy steels

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Journal of Materials Science & Technology 2020年第14期47卷 202-210页

作者： Yuanjie Zhi Tao Yang dongmei Fu School of Automation and Electrical Engineering University of Science and Technology BeijingBeijing100083China Beijing Engineering Research Center of Industrial Spectrum Imaging University of Science and Technology BeijingBeijing 100083China

The paper proposes a new deep structure model,called Densely Connected Cascade Forest-Weighted K Nearest Neighbors(DCCF-WKNNs),to implement the corrosion data modelling and corrosion ***,we collect 409 outdoor atmospheric corrosion samples of low-alloy steels as experiment ***,we give the proposed methods process,including random forests-K nearest neighbors(RF-WKNNs)and ***,we use the collected datasets to verify the performance of the proposed *** results show that compared with commonly used and advanced machine-learning algorithms such as artificial neural network(ANN),support vector regression(SVR),random forests(RF),and cascade forests(cForest),the proposed method can obtain the best prediction *** addition,the method can predict the corrosion rates with variations of any one single environmental variable,like pH,temperature,relative humidity,SO2,rainfall or Cl-.By this way,the threshold of each variable,upon which the corrosion rate may have a large change,can be further obtained.

关键词： Random forests Deep forest model Low-alloy steels Outdoor atmospheric corrosion Prediction and data-mining

Topological entropy of sets of generic points for actions of amenable groups

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Science China Mathematics 2018年第5期61卷 869-880页

作者： dongmei Zheng Ercai Chen School of Physical and Mathematical Sciences Nanjing Tech University School of Mathematical Sciences and Institute of Mathematics Nanjing Normal University

Let G be a countable discrete infinite amenable group which acts continuously on a compact metric space X and let μ be an ergodic G-invariant Borel probability measure on X. For a fixed tempered F?lner sequence {Fn} in G with limn→+∞|Fn|/log n= ∞, we prove the following result:h_top^B(G_μ, {F_n}) = h_μ(X, G),where G_μ is the set of generic points for μ with respect to {F_n} and h_top^B(G_μ, {F_n}) is the Bowen topological entropy(along {F_n}) on G_μ. This generalizes the classical result of Bowen(1973).

关键词： entropy generic point amenable group variational principle

An Improvement for GVW

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Journal of Systems Science & Complexity 2022年第1期35卷 427-436页

作者： ZHENG Licui LI dongmei LIU Jinwang Department of Mathematics and Computing Sciences Hunan University of Science and TechnologyXiangtan 411201China

Gao,et al.(2015)gave a simple algorithm to compute Gr?bner bases named *** can be used to compute Gr?bner bases for both ideals and syzygies at the same time,and the latter plays an important role in free resolutions in homological *** GVW algorithms the authors need to compute all the J-pairs firstly and then use GVW criterion(which refers the criterions used in GVW)to determine which one is useless or which one the authors should do *** this paper,based on the study of relations between J-pairs,the authors propose the concept of *** concept allows the authors to filter the useless J-pairs in a rather convenient ***,by using this concept,the authors may easily determine which two pairs’J-pair need not to be ***,the Gr?bner basis which the authors obtained is relatively simpler than the one in GVW.

关键词： Factor Grobner basic GVW

A Meta-Analysis on Phenotypic Variation in Cadmium Accumulation of Rice and Wheat:Implications for Food Cadmium Risk Control

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Pedosphere 2019年第5期29卷 545-553页

作者： LI Xiaofang ZHOU dongmei Key Laboratory of Agricultural Water Resources Hebei Key Laboratory of Soil EcologyThe Innovative Academy of Seed DesignCentre for Agricultural Resources ResearchInstitute of Genetics and Developmental BiologyChinese Academy of SciencesShijiazhuang 050021 (China) Institute of Soil Science Chinese Academy of SciencesNanjing 210008 (China) School of Environment Nanjing UniversityNanjing 210093 (China)

In some densely-populated countries, farmland has been widely cadmium (Cd) contaminated, and the utilization of the contaminated farmland for crop production is currently unavoidable. This necessitates the use of low-Cd crops (i.e., pollution-safe cultivars, the crop varieties with the ability to accumulate a low level of Cd in their edible parts when grown on polluted soil) in these areas and highlights the importance of knowledge on phenotypic variation in crop Cd accumulation for food Cd risk control. Studies on phenotypic variation in heavy metal accumulation started decades ago for a wide range of crops, and synthesis of the scattered experimental results in the literature is in need. We built a Low-Cd Crops Database based on literature research, and relevant meta-analysis was performed to quantitatively explore the phenotypic variation in Cd uptake and translocation of rice and wheat. Considerable variability existed among rice (median grain Cd bioconce nt ration factor (BCF) of 0.10) and wheat (median grain Cd BCF of 0.21) phenotypes in grain Cd accumulation, and this variability was labile to soil pH and the level of Cd stress. Wheat statistically had a higher root-to-shoot Cd-translocating ability than rice, highlighting potential food Cd risks and the importance of growing low-Cd wheat in slightly Cd-contaminated regions. Meanwhile, no correlations were detected among soil-to-root, root-to-shoot, and shoot-to-grain translocation factors, implying that Cd uptake and internal translocation in crops were probably controlled by different underlying gene tic mechanisms. Root-to-shoot Cd transport could be a favorable target trait for selecting and breeding low-Cd rice and wheat. In all, this review provides a comprehensive low-Cd crop list for remediation practice and a systematic meta-analysis inferring food Cd risks based on plant capacity for Cd accumulation and desired traits for low-Cd crop breeding.

关键词： bioconcentration factor Cd contamination Cd stress heavy metal low-Cd crops plant uptake polution-safe cultivars soil pH translocation factor

Factorization for n-D Polynomial Matrices over Arbitrary Coefficient Field

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Journal of Systems Science & Complexity 2020年第1期33卷 215-229页

作者： LIU Jinwang LI dongmei ZHENG Licui School of Mathematics and Computing Sciences Hunan University of Science and TechnologyXiangtan 411201China

Multivariate(n-D)polynomial matrix factorization is one of important research contents in multidimensional(n-D)systems,circuits,and signal *** this paper,several results on n-D polynomial matrices factorization over arbitrary coefficient fields are *** on these results,generalizations of some results on general matrix factorization are obtained for given n-D polynomial matrices whose maximal order minors or lower order minors satisfy certain *** proposed results fit for arbitrary coefficient field and have a wide range of application.

关键词： Coefficient field matrix factorization multidimensional polynomial matrix order minor

A Mathematical Model with Delays for Schistosomiasis Japonicum Transmission

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Chinese Annals of Mathematics,Series B 2010年第4期31卷 433-446页

作者： Yu YANG dongmei XIAO Department of Mathematics Shanghai Jiao Tong University Shanghai 200240 China Corresponding author. Department of Mathematics Shanghai Jiao Tong University Shanghai 200240 China

A dynamic model of schistosoma japonicum transmission is presented that incorporates effects of the prepatent periods of the different stages of schistosoma into Baxbour＇s model. The model consists of four delay differential equations. Stability of the disease free equilibrium and the existence of an endemic equilibrium for this model are stated in terms of a key threshold parameter. The study of dynamics for the model shows that the endemic equilibrium is globally stable in an open region if it exists and there is no delays, and for some nonzero delays the endemic equilibrium undergoes Hopf bifurcation and a periodic orbit emerges. Some numerical results are provided to support the theoretic results in this paper. These results suggest that prepatent periods in infection affect the prevalence of schistosomiasis, and it is an effective strategy on schistosomiasis control to lengthen in prepatent period on infected definitive hosts by drug treatment （or lengthen in prepatent period on infected intermediate snails by lower water temperature）.

关键词： A mathematical model Schistosoma japonicum transmission Dynamics Globally stable Periodic orbits

Polymer flooding: Current status and future directions

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Petroleum Science 2023年第2期20卷 910-921页

作者： R.S.Seright dongmei Wang New Mexico Institute of Mining and Technology SocorroNMUSA University of North Dakota Grand ForksNDUSA

This review presents our perspective on the factors that have brought polymer flooding to its current state. Insights are provided on why HPAM is the dominant polymer used as well as what is needed to make alternative polymers and mobility-control methods viable. Explanation is given for why large polymer banks are needed for polymer flooding, and design of the injected polymer viscosity is detailed for cases with/without crossflow. The role of fractures and horizontal wells are discussed for improving injectivity and extending polymer flooding to recover oils with viscosities as high as 10,000 cP. Operational improvements are described to minimize mechanical and oxidative stability to allow HPAM polymers to be viable to 70 °C and ATBS polymers to 120 °C. Key factors affecting polymer retention are summarized. The paper points out unresolved issues and future directions for polymer flooding.

关键词： Polymer flooding Reservoir sweep improvement

Quality Improvement through Contract Design and Competition in Agricultural Suppply Chains

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Journal of Systems Science and Systems Engineering 2024年第6期33卷 716-735页

作者： Jinxin Yang dongmei Xue Weihua Zhou School of Management Zhejiang UniversityHangzhou310058China Alibaba Business School Hangzhou Normal UniversityHangzhou311121China

Quality emerges as a pivotal competitive factor for agricultural ***,retailers within agricultural supply chains have begun investing in technologies to improve quality and designing contracts to incentivize farmers to enhance their labor *** farmers and the retailers incur different quality investment costs,with this cost increasing in the quality they ***,retailers have embraced the farmer-competition strategy,employing competition to stimulate improved agricultural product quality among *** construct a Stackelberg game model to analyze how farmers’quality investment,retailer’s contract design,and profits are affected by the retailer’s farmer-competition *** show that the farmer competition introduced by the retailer is not always effective in improving the farmer’s quality ***,the competition cannot always lead to additional profits for the ***,the supply chain profit suffers from the retailer’s farmer-competition strategy when the competition intensity between farmers is relatively *** results offer insights for retailers by identifying how should the retailer design the contract to improve the farmer’s quality effort given the existence of the farmer competition and under what conditions the retailer should adopt the farmer-competition strategy.

关键词： Quality management farmer competition agricultural supply chain contract farming

System Model and Equilibrium Strategy of Mobile Users in a Hybrid Access Network

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Journal of Systems Science and Systems Engineering 2019年第2期28卷 224-237页

作者： dongmei Zhao Shunfu Jin Wuyi Yue School of Information Science and Engineering Yanshan UniversityQinhuangdao 066000 China Department of Intelligence and Informatics Konan University Kobe Japan

Mobile users usually access the Internet via a hybrid access network, in which cellular and Wi-Fi networks are available alternatively. In the hybrid access network, a mobile user decides to send or not to send a packet according to the number of packets already in the system and the phase of the server. In order to evaluate the system performance of the hybrid access network, in this paper we first establish a fully observable continuous time Markovian queueing system. Then, we present an exact analysis to investigate the behavior of the mobile users in the network. Through iterations and diagonalization, we obtain the expected sojourn time of a newly arriving packet in a closed form. Moreover, with the monotonicity for the expected sojourn time of a newly arriving packet, we prove the existence of the Nash equilibrium strategy. Finally, we analyze the socially optimal strategy and motivate the mobile users to accept the socially optimal strategy by changing the sojourn cost.

关键词： Hybrid access network observable queueing system expected sojourn time Nash equilibriumstrategy socially optimal strategy