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基于特征概念自动提取系统的研究

湖南城市学院学报（自然科学版） 2006年第1期15卷 69-71,74页

作者：曾朝晖邓曙光陆文彦湖南城市学院湖南益阳413000 中南大学长沙410083

文本分类与文本信息特征概念的提取是当前智能信息服务研究的重点.为自动获取新的特征概念,提出了一种基于特征概念的自动提取系统.该系统包括分词、综合文本词权处理、类别归属和特征概念提取等部分,能有效地从概念上提取文本类特征,... 详细信息

文本分类与文本信息特征概念的提取是当前智能信息服务研究的重点.为自动获取新的特征概念,提出了一种基于特征概念的自动提取系统.该系统包括分词、综合文本词权处理、类别归属和特征概念提取等部分,能有效地从概念上提取文本类特征,提高文本自动分类的准确性.

关键词：特征概念文本分类特征提取

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基于集群智能的高速公路交通状态识别算法

山东科学 2022年第3期35卷 72-81页

作者：曾朝晖王江锋教欣萍熊慧媛龚希志北京交通大学交通运输学院综合交通运输大数据应用技术交通运输行业重点实验室北京100044 河南省交通规划设计研究院股份有限公司河南郑州450000

针对传统交通状态识别算法仅考虑交通参数个体特征差异而存在识别率较低的问题,引入集群智能概念,提出了既考虑交通参数个体特征差异,又考虑个体参数所蕴含的群体特征差异性的高速公路交通状态识别算法。由于模糊C均值聚类算法(fuzzy C-... 详细信息

针对传统交通状态识别算法仅考虑交通参数个体特征差异而存在识别率较低的问题,引入集群智能概念,提出了既考虑交通参数个体特征差异,又考虑个体参数所蕴含的群体特征差异性的高速公路交通状态识别算法。由于模糊C均值聚类算法(fuzzy C-means algorithm,FCM)在交通状态识别泛化能力上存在收敛缓慢的不足,基于反向学习策略以及鲸鱼优化算法(whale optimization algorithm,WOA),考虑个体交通参数所蕴含的集群行为增强了交通状态初始聚类中心种群的多样性,设计了一种具有良好的全局搜索能力集群智能的高速公路交通状态识别算法,融合了反向学习、WOA和FCM算法,克服了FCM识别算法容易陷入局部最优的局限。实证分析结果表明,所提出的交通状态识别算法具有良好的识别效果,准确率达到92%,且收敛速度较FCM算法更快。

关键词：高速公路交通状态模式识别鲸鱼算法模糊聚类反向学习

Optimal proportional reinsurance and investment problem with jump-diffusion risk process under effect of inside information

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Frontiers of Mathematics in China 2014年第4期9卷 965-982页

作者： Jie XIONG Shuaiqi ZHANG hui zhao Xihuan zeng Department of Mathematics FST University of Macao Macao China School of Economics and Commerce Guangclong University of TechnologyGuangzhou 510520 China Department of Statistics Hebei University of Technology Tianjin 300401 China Department of Mathematics Tianjin University Tianjin 300072 China Institute of Business Administration University of Macao Macao China

We study optimal investment and proportional reinsurance strategy in the presence of inside information. The risk process is assumed to follow a compound Poisson process perturbed by a standard Brownian motion. The insurer is allowed to invest in a risk-free asset and a risky asset as well as to purchase proportional reinsurance. In addition, it has some extra information available from the beginning of the trading interval, thus introducing in this way inside information aspects to our model. We consider two optimization problems： the problem of maximizing the expected exponential utility of terminal wealth with and without inside information, respectively. By solving the corresponding Hamilton-Jacobi-Bellman equations, explicit expressions for their optimal value functions and the corresponding optimal strategies are obtained. Finally, we discuss the effects of parameters on the optimal strategy and the effect of the inside information by numerical simulations.

关键词： Inside information investment reinsurance jump diffusion

On First Returning Time and Last Exit Time of a Class of Markov Chain

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Acta Mathematica Sinica,English Series 2013年第2期29卷 331-344页

作者： hui zeng ZHANG Min Zhi zhao Lei WANG Department of Mathematics Hangzhou Normal University Department of Mathematics Zhejiang University

Let {Xn} be a Markov chain with transition probability pij =： aj-（i-1）＋,i,j ≥ 0, where aj=0 providedj 〈 0, a0 〉 0, a0＋a1〈 1 and ∑∞n=0 an= 1. Let μ∑∞n=1nan. It is known that {Xn} is positive recurrent when μ 〈 1; is null recurrent when μ= 1; and is transient when μ 〉 1. In this paper, the integrability of the first returning time and the last exit time are discussed. Keywords Geom/G/1 queuing model, first returning time, last exit time, Markov chain

关键词： Geom/G/1 queuing model first returning time last exit time Markov chain

Time-consistent investment-reinsurance strategies towards joint interests of the insurer and the reinsurer under CEV models

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Science China Mathematics 2017年第2期60卷 317-344页

作者： zhao hui WENG ChengGuo SHEN Yang zeng Yan School of Science Tianjin University Tianjin 300072 China Department of Statistics and Actuarial Science University of Waterloo Waterloo ON N2L 3GI Canada Department of Mathematics and Statistics York University Toronto ON M3J IP3 Canada Lingnan (University) College Sun Yat-sen University Guangzhou 510275 China

The present paper studies time-consistent solutions to an investment-reinsurance problem under a mean-variance *** paper is distinguished from other literature by taking into account the interests of both an insurer and a reinsurer *** claim process of the insurer is governed by a Brownian motion with a drift.A proportional reinsurance treaty is considered and the premium is calculated according to the expected value *** the insurer and the reinsurer are assumed to invest in a risky asset,which is distinct for each other and driven by a constant elasticity of variance *** optimal decision is formulated on a weighted sum of the insurer’s and the reinsurer’s surplus *** a verification theorem,which is established with a formal proof for a more general problem,explicit solutions are obtained for the proposed investment-reinsurance ***,numerous mathematical analysis and numerical examples are provided to demonstrate those derived results as well as the economic implications behind.

关键词： investment-reinsurance problem mean-variance analysis time-consistent strategy constant elas-ticity of variance model

Waiting times and stopping probabilities for patterns in Markov chains

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Applied Mathematics(A Journal of Chinese Universities) 2018年第1期33卷 25-34页

作者： zhao Min-zhi XU Dong ZHANG hui-zeng School of Mathematical Sciences Zhejiang University Department of Mathematics Hangzhou Normal University

Suppose that C is a finite collection of patterns. Observe a Markov chain until one of the patterns in C occurs as a run. This time is denoted by τ. In this paper, we aim to give an easy way to calculate the mean waiting time E(τ) and the stopping probabilities P(τ = τA)with A ∈ C, where τA is the waiting time until the pattern A appears as a run.

关键词： pattern Markov chain stopping probability waiting time

High adaptability of Pinus sylvestris *** to drought-induced soil nutrient deficiency

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Ecological Processes 2022年第1期11卷 512-524页

作者： Jingling Zhang Guigang Lin Qiong zhao De‑hui zeng CAS Key Laboratory of Forest Ecology and Management Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China Daqinggou Ecological Station Institute of Applied EcologyChinese Academy of SciencesShenyang 110016China University of Chinese Academy of Sciences Beijing 100049China School of Resources and Environmental Engineering Anhui UniversityHefei 230601China

Background:Drought can exert a profound influence on soil nutrient availability,and understanding whether and how tree species adapt to this change is a critical priority for predicting the consequence of climate change on forest structure and *** objective of this study was to examine the adaptability of Mongolian pine(Pinus sylvestris ***)to drought‑induced changes in soil nutrient availability from the perspective of root ***:We conducted a 7‑year precipitation manipulation experiment with three levels of throughfall reduction(0%,30%,and 50%)to simulate different drought *** measured soil physicochemical properties and fineroot nutrient concentrations and biomass,and calculated the stoichiometric homeostatic regulation coefficient(1/H)of fine ***:Drought reduced soil organic carbon(C),nitrogen(N),phosphorous(P)and inorganic N concentrations,as well as ratios of total N to total P,and available N to available P in the 0–20 cm soil *** contrast,drought had no significant effect on fine‑root N and P concentrations,and fine‑root biomass in the 0–40 cm soil *** roots displayed high homeostatic regulation coefficients of N(with 1/H values of 0.19 and 0)and P(with 1/H values of 0.33 and 0)concentrations in 0–20 and 20–40 cm soil layers,***:Our results indicate that drought leads to soil nutrient deficiency and the decoupling between N and P cycling,and provide evidence that Mongolian pine has high adaptability to drought‑induced decrease in soil nutrient availability by maintaining great fine‑root biomass to ensure sufficient nutrient uptake.

关键词： C:N:P stoichiometry Fine‑root biomass Stoichiometric homeostasis Throughfall reduction

自动乳腺全容积成像和磁共振成像、钼靶影像学特征在三阴性乳腺癌的诊断及预后分析的价值

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临床放射学杂志 2025年第1期44卷 69-75页

作者：张琪茹赵辉韩华河南省新乡市中心医院超声科二 453000

目的探讨自动乳腺全容积成像(ABVS)和MRI、钼靶影像学特征对三阴性乳腺癌(TNBC)的诊断及预后的价值。方法搜集经病理检测与免疫组织化学检测证实为TNBC患者47例和非三阴性乳腺癌(nTNBC)患者43例。均行ABVS、MRI、钼靶检查,比较两组患者... 详细信息

目的探讨自动乳腺全容积成像(ABVS)和MRI、钼靶影像学特征对三阴性乳腺癌(TNBC)的诊断及预后的价值。方法搜集经病理检测与免疫组织化学检测证实为TNBC患者47例和非三阴性乳腺癌(nTNBC)患者43例。均行ABVS、MRI、钼靶检查,比较两组患者的临床资料、ABVS、MRI、钼靶影像学特征、不同检查方式对TNBC的诊断效能及预后不同TNBC患者的影像学特征。结果TNBC组患者年龄>35岁、肿瘤直径>2 cm、病理分期为Ⅲ期、淋巴结转移患者占比显著高于nTNBC组(P<0.05);TNBC与nTNBC患者的ABVS(肿块形态、边缘、钙化类型、后方回声衰减)、MRI(肿块大小、形态、边缘、内部强化、表观扩散系数、峰值强化率、峰值时间值)、钼靶检查(钙化情况)影像学特征差异均有统计学意义(P<0.05);ABVS、MRI联合钼靶检查诊断TNBC的特异度、敏感度、准确率、预测率均显著高于单一或任意两种检查方法(P<0.05);TNBC预后良好、预后不良患者钙化情况、汇聚征、后方回声衰减、内部强化、峰值强化率差异均有统计学意义(P<0.05)。结论ABVS、MRI联合钼靶影像学特征在TNBC诊断及预测预后中的应用价值较高。

关键词：三阴性乳腺癌自动乳腺全容积成像磁共振成像乳腺钼靶X线预后

High-resolution characterization of the fretting corrosion of Alloy 690 in the simulated secondary water of pressurized water reactor

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Journal of Materials Science & Technology 2023年第20期151卷 30-40页

作者： You Wang Zhangjian Zhou hui Wang Jiang Ju zhao Shen Xiaoqin zeng School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Interdisciplinary Materials Research Center Institute for Advanced StudyChengdu UniversityChengdu 610041China School of Materials Science and Engineering Shanghai Jiao Tong UniversityNo.800 Dongchuan RoadShanghai 200240China

The worn scars on Alloy 690 after the fretting corrosion testing in simulated pressurized water reactor(PWR)secondary water have been comprehensively analyzed by scanning transmission electron microscopy(STEM)and transmission Kikuchi diffraction(TKD).The high-quality characterization results experimentally show that the fretting wear accelerates the corrosion of Alloy 690 in two *** first one is to break the integrity of the oxide scale by introducing cavities at the oxide grain *** second one is to alter the microstructure of the underneath matrix,forming a nano-grained matrix *** increased grain boundary density in this layer can accelerate the consumption of Cr in the near-surface *** loss of oxide scale integrity and the accelerated Cr consumption are believed to contribute to the deteriorated corrosion resistance of Alloy 690 during the fretting corrosion process.

关键词： Alloy 690 Corrosion Fretting wear Transmission electron microscopy Transmission Kikuchi Diffraction