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Development of diabetic complications and influencing factors among 32653 type 2 diabetes patients:retrospective cohort study using a multi-state Markov
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作者 Shu-Yuan Shi Hou-Yu Zhao +5 位作者 Zhi-Ke Liu Ruo-Gu Meng Peng Shen Si-Yan Zhan Hong-Bo Lin Feng Sun 《Medical Data Mining》 2024年第2期1-8,共8页
Background:Patients with type 2 diabetes are at high risk for developing multiple chronic complications.However,there is a lack of studies of the cumulative number of diabetic complications in China.Methods:A retrospe... Background:Patients with type 2 diabetes are at high risk for developing multiple chronic complications.However,there is a lack of studies of the cumulative number of diabetic complications in China.Methods:A retrospective cohort study was performed from 2009 to 2021.Type 2 diabetes patients who were first diagnosed after the age of 35 years between January 1,2009,and December 31,2017,were included.Five states were defined according to the number of chronic complications:no(S0),one(S1),two(S2),three(S3),and four or more complications(S4).A multi-state Markov model was constructed to estimate transition probability,transition intensity,mean sojourn time,and the possible factors for each state.Results:The study included 32653 type 2 diabetes patients(mean age,59.59 years;15929(48.8%)male),and mean follow-up time of 7.75 years.In all,4375 transitions were observed.The 12-year transition probability of from state S0 to S1 was the lowest at 16.4%,while that from S2 to S3 was the highest,at 45.6%.Higher fasting blood glucose,lower high-density lipoprotein cholesterol,higher total cholesterol,and an unhealthy diet were associated with higher risk of progression from S0 to S1.Being female,less than 60 years old,weekly physical activity,and vegetarian diet decreased this risk.Being female and less than 60 years old reduced the likelihood of transition from S1 to S2,whereas lower high-density lipoprotein cholesterol increased this likelihood.Conclusions:Following the occurrence of two complications in type 2 diabetes patients,the risk for accumulating a third complication within a short time is significantly increased.It is important to take advantage of the stable window period when patients have fewer than two complications,strengthen the monitoring of blood glucose and blood lipids,and encourage patients to maintain good living habits to prevent further deterioration. 展开更多
关键词 multi-state Markov model transition probability type 2 diabetes diabetic chronic complications
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Inverse Transformation of Elliptical Relative State Transition Matrix 被引量:1
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作者 Jianfeng Yin Yinrui Rao Chao Han 《International Journal of Astronomy and Astrophysics》 2014年第3期419-428,共10页
A new set of relative orbit elements (ROEs) is used to derive a new elliptical formation flying model in previous work. In-plane and out-of-plane relative motions can be completely decoupled, which benefits elliptical... A new set of relative orbit elements (ROEs) is used to derive a new elliptical formation flying model in previous work. In-plane and out-of-plane relative motions can be completely decoupled, which benefits elliptical formation design. In order to study the elliptical control strategy and perturbation effects, it is necessary to derive the inverse transformation of the relative state transition matrix based on relative orbit elements. Poisson bracket theory is used to obtain the linear transformations between the two representations: the relative orbit elements and the geocentric orbital frame. In this paper, the details of these transformations are presented. 展开更多
关键词 RELATIVE ORBIT Elements ELLIPTICAL Formation FLYING RELATIVE State transition matrix Inverse Transformation POISSON BRACKET
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Correlation of Claudins6 (CLDN6) gene expression in meningioma tissue with the expression of matrix metalloproteinases (MMPs)/tissue inhibitors of matrix metalloproteinase (TIMPs) and epithelial-mesenchymal transition (EMT) genes
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作者 An-Qiang Yang Xiao-Bin Yang Ping Li 《Journal of Hainan Medical University》 2017年第17期117-120,共4页
Objective:To study the correlation of Claudins6 (CLDN6) gene expression in meningioma tissue with the expression of matrix metalloproteinases (MMPs)/tissue inhibitors of matrix metalloproteinase (TIMPs) and epithelial... Objective:To study the correlation of Claudins6 (CLDN6) gene expression in meningioma tissue with the expression of matrix metalloproteinases (MMPs)/tissue inhibitors of matrix metalloproteinase (TIMPs) and epithelial-mesenchymal transition (EMT) genes.Methods:Meningioma tissue samples that were surgically removed in Yibin First People's Hospital between April 2014 and May 2017 were selected, normal arachnoid tissue samples that were collected from decompressive craniectomy in Yibin First People's Hospital during the same period were selected, and the expression of CLDN6, MMPs/TIMPs and EMT genes in tissues were determined.Results: CLDN6 protein expression in meningioma tissue was significantly lower than that in normal arachnoid tissue;EMMPRIN, MMP2, MMP9, Vimentin and N-cadherin protein expression in meningioma tissue were significantly higher than those in normal arachnoid tissue while TIMP1, TIMP2, E-cadherin andα-catenin protein expression were significantly lower than those in normal arachnoid tissue;EMMPRIN, MMP2, MMP9, Vimentin and N-cadherin protein expression in meningioma tissue with higher CLDN6 expression were significantly lower than those in meningioma tissue with lower CLDN6 expression while TIMP1, TIMP2, E-cadherin andα-catenin protein expression were significantly higher than those in meningioma tissue with lower CLDN6 expression. Conclusion: Lowly expressed CLDN6 gene in meningioma tissue can increase the hydrolysis activity of MMPs, induce epithelial-mesenchymal transition and thus promote the invasive growth of meningioma. 展开更多
关键词 MENINGIOMA Claudins6 Invasion matrix METALLOPROTEINASE Epithelial-mesenchymal transition
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Correlation of annexin A2 expression with epithelial-mesenchymal transition and extracellular matrix degradation in bile duct carcinoma
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作者 Yu-Bing Zhu Wei Hu 《Journal of Hainan Medical University》 2017年第24期101-104,共4页
Objective: To investigate the correlation of annexin A2 expression with epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) degradation in bile duct carcinoma. Methods: A total of 60 patients with p... Objective: To investigate the correlation of annexin A2 expression with epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) degradation in bile duct carcinoma. Methods: A total of 60 patients with primary bile duct carcinoma who accepted bile duct carcinoma laparotomy in our hospital between April 2009 and May 2017 were selected. The bile duct carcinoma tissue and adjacent normal tissue were kept during operation and enrolled in bile duct cancer group (n=60) and normal control group (n=60). The protein expression of annexin A2, EMT marker molecules, MMPs subtypes and TIMPs subtypes in two groups of specimens were detected, and Pearson test was used to evaluate the correlation of annexin A2 expression with EMT and ECM degradation in bile duct carcinoma tissue. Results: Annexin A2 expression in bile duct cancer group was higher than that in normal control group;E-cadherin, β-catenin and syndecan-1 protein expression in bile duct cancer group were lower than those in control group whereas P-cadherin and Vimentin protein expression were higher than those in normal control group;MMP-2, MMP-7 and MMP-9 protein expression in bile duct cancer group were higher than those in normal control group whereas TIMP-1 and TIMP-2 protein expression were lower than those in normal control group. Pearson test showed that the annexin A2 expression in bile duct carcinoma was directly correlated with the protein expression of EMT marker molecules, MMPs subtypes and TIMPs subtypes. Conclusion: annexin A2 increases in bile duct carcinoma, and it can regulate EMT and ECM degradation process to affect the disease outcome. 展开更多
关键词 BILE duct carcinoma ANNEXIN A2 Epithelial-mesenchymal transition EXTRACELLULAR matrix
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Multimodal process monitoring based on transition-constrained Gaussian mixture model 被引量:4
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作者 Shutian Chen Qingchao Jiang Xuefeng Yan 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2020年第12期3070-3078,共9页
Reliable process monitoring is important for ensuring process safety and product quality.A production process is generally characterized bymultiple operation modes,and monitoring thesemultimodal processes is challengi... Reliable process monitoring is important for ensuring process safety and product quality.A production process is generally characterized bymultiple operation modes,and monitoring thesemultimodal processes is challenging.Most multimodal monitoring methods rely on the assumption that the modes are independent of each other,which may not be appropriate for practical application.This study proposes a transition-constrained Gaussian mixture model method for efficient multimodal process monitoring.This technique can reduce falsely and frequently occurring mode transitions by considering the time series information in the mode identification of historical and online data.This process enables the identified modes to reflect the stability of actual working conditions,improve mode identification accuracy,and enhance monitoring reliability in cases of mode overlap.Case studies on a numerical simulation example and simulation of the penicillin fermentation process are provided to verify the effectiveness of the proposed approach inmultimodal process monitoring with mode overlap. 展开更多
关键词 Multimodal process monitoring Gaussian mixture model State transition matrix Process control Process systems Systems engineering
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An Improved Method for Estimating the Transition Probability Using Diameter Growth in Even-aged Forest Stands 被引量:1
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作者 Jia Naiguang Kang Huining Xu SongDepartment of Foundation Courses. Beijing Forestry University 《北京林业大学学报》 CAS CSCD 北大核心 1992年第S2期47-54,共8页
The method of Zeng et al. (1991) employed diameter growth to estimate the transition probability of the matrix model in uneven-aged forest stands. In this paper the Weibull distribution for even-aged forest stands ins... The method of Zeng et al. (1991) employed diameter growth to estimate the transition probability of the matrix model in uneven-aged forest stands. In this paper the Weibull distribution for even-aged forest stands instead of uniform distribution chosen by Zeng is used. By comparing the results of the improved method with those of the original method of Zeng, it turns out that the improved method of Zeng given in this paper is more efficient. 展开更多
关键词 even-aged FOREST STANDS matrix model transition PROBABILITY parameter estimation UNIFORM DISTRIBUTION Weibull DISTRIBUTION
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Practical Method for Determining All the Minimum Solutions of Fuzzy Matrix Equation and Transitive Closure of Fuzzy Relation 被引量:2
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作者 阎家杰 赵万忠 《Chinese Quarterly Journal of Mathematics》 CSCD 1993年第4期99-103,共5页
In this paper,the new theory frame and practical methhod for determining all the minimum solutions of Fuzzy matrix equation and transitive closure of Fuzzy relation is described,and it has been carried out on the mier... In this paper,the new theory frame and practical methhod for determining all the minimum solutions of Fuzzy matrix equation and transitive closure of Fuzzy relation is described,and it has been carried out on the miero-computer quickly and accurately. 展开更多
关键词 fuzzy matrix equation minimum solution fuzzy relation transitive closure
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Effect of WNT5A on epithelial-mesenchymal transition and its correlation with tumor invasion and metastasis in nasopharyngeal carcinoma 被引量:1
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作者 Hong-Hai Zhu Xiao-Yuan Zhu +2 位作者 Ming-Hui Zhou Gen-Yang Cheng Wei-Hua Lou 《Asian Pacific Journal of Tropical Medicine》 SCIE CAS 2014年第6期488-491,共4页
Objective:To investigate the correlation between nasopharyngeal carcinoma cell WNT5A and epithelial-mesenchytnal transition(emt)/metastasis,and investigate its possible mechanisms.Methods:RT-PCR and gene transfection ... Objective:To investigate the correlation between nasopharyngeal carcinoma cell WNT5A and epithelial-mesenchytnal transition(emt)/metastasis,and investigate its possible mechanisms.Methods:RT-PCR and gene transfection were used to detect the expression of nasopharyngeal carcinoma cell strains WNT5A and EMT related factor 5-8F.Transient transfcction of NPC cell line 5-8F was determined by liposome of plasmid with WNT5A gene.The differential expressions of WNTSA and EMT-related factors in cells before and after transfection were detected by RTPCR.Cell scratch assay and Transwell assay were used to detect the motility abilities of cells before and after 5-8F transfection.Results:The expressions of WNT5A and EMT related factors matrix metalloproleinasc-2 of the WNTSA transferred group in the nasopharyngeal carcinoma cell line 5-8F were higher than the blank control group and the empty vector transferred group,and the transfer ability of the WNTSA transferred group was higher than that in the blank control group and the empty vector transferred group,while the expressions of EMT related factors E-cadherin were lower than that in the blank control group and the empty vector transferred group,and the transfer ability of the WNT5A transferred group was higher than that in the blank control group and the empty vector transferred group.Conclusions:In nasopharyngeal carcinoma cells,WNT5A can regulate the epithelial-mesenchymal transition and affect the ability of tumor invasion and metastasis of nasopharyngeal carcinoma. 展开更多
关键词 WNT5A Epithelial-mesenchymal transition matrix metalloproteinase-2 E-CADHERIN Nasopharyngeal cancer METASTASIS
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Phase Transitions of a Dilute O(n) Model
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作者 GUOWen-An HenkW.J.B1ote LIUYuan-Yuan 《Communications in Theoretical Physics》 SCIE CAS CSCD 2004年第6期911-916,共6页
We investigate tricritical behavior of the O(n) model in two dimensions by means of transfer-matrix and finite-size scaling methods. For this purpose we consider an O(n) symmetric spin model on the honeycomb lattice w... We investigate tricritical behavior of the O(n) model in two dimensions by means of transfer-matrix and finite-size scaling methods. For this purpose we consider an O(n) symmetric spin model on the honeycomb lattice with vacancies; the tricritical behavior is associated with the percolation threshold of the vacancies. The vacancies are represented by face variables on the elementary hexagons of thelattice. We apply a mapping of the spin degrees of freedom model on a non-intersecting-loop model, in which the number n of spin components assumes the role of a continuously variable parameter. This loop model serves as a suitable basis for the construction of the transfer matrix.Our results reveal the existence of a tricritical line, parametrized by n, which connects the known universality classes of the tricritical Ising model and the theta point describing the collapse of a polymer. On the other side of theIsing point,the tricritical line extends to the n = 2 point describing a tricritical O(2) model. 展开更多
关键词 phase transition dilute O(n) model tricritical behavior transfer matrix
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Expressions and clinical significances of MMP-2 and TIMP-2 mRNA in bladder transitional cell carcinomas
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作者 Yunyan Wang Junsong Meng +2 位作者 Haijun Zhuang Jianquan Hou Duangai Wen 《The Chinese-German Journal of Clinical Oncology》 CAS 2011年第5期278-281,共4页
Objective:The aim of the study was to investigate the expressions of matrix metalloproteinase-2(MMP-2) and tissue inhibitor of MMP-2(TIMP-2) mRNA in transitional cell carcinomas of bladder and discuss their clinical s... Objective:The aim of the study was to investigate the expressions of matrix metalloproteinase-2(MMP-2) and tissue inhibitor of MMP-2(TIMP-2) mRNA in transitional cell carcinomas of bladder and discuss their clinical significances.Methods:Using RT-PCR and real time quantitative PCR(RQ-PCR) technique,the expressions of MMP-2 and TIMP-2 mRNA of 45 cases of bladder carcinoma(tumor group) and 10 cases of normal bladder tissue(control group) were analyzed.Results:MMP-2 and TIMP-2 were not expressed in control group.MMP-2 was expressed in 30 cases tumor samples and TIMP-2 was expressed in 26 cases.The expression of MMP-2 mRNA in non-muscle invasive bladder cancers and grade I cancers was lower than that in muscle invasive bladder cancers and grades II-III cancers respectively.The differences were statistically significant(P<0.05).The expression of MMP-2 in recurrent patients was higher than that in incipient patients.TIMP-2 mRNA expression decreased with grades and stage.The expression of TIMP-2 in non-muscle invasive bladder cancers and grade I cancers was higher than that in muscle invasive bladder cancers and grades II-III cancers respectively.There was statistical difference between two groups(P < 0.05).TIMP-2 expression in incipient patients was higher than that in recurrent patients,but the difference was not significant(P>0.05).Conclusion:These results suggest that MMP-2 and TIMP-2 play an important role in the invasion step of transitional cell carcinoma of bladder.MMP-2 may become a new approach to the diagnosis of bladder carcinoma. 展开更多
关键词 transitional cell carcinoma of bladder matrix metalloproteinase-2(MMP-2) tissue inhibitor of MMP-2(TIMP-2)
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KINETO-ELASTODYNAMIC ANALYSIS USED BY THE MATRIX-TRANSIT METHOD
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作者 Tong Zhou Zou HujunShanghai Jiaotong University 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 1995年第2期149-154,共6页
An element based on the harmonic functions for Performing vibration analysis oflinkages was developed to propose the matrix-transit equations and the kineto-elastrodynamics(KED) different equations. Method and the KED... An element based on the harmonic functions for Performing vibration analysis oflinkages was developed to propose the matrix-transit equations and the kineto-elastrodynamics(KED) different equations. Method and the KED equations was continllous undertaken by themodal superposition approach. The results from those equations include the quasistatic parts andthe dynamic parts. The dynamic parts equaled to the developing parts of the computationaccurations. 展开更多
关键词 Kineto-elastrodynamics (KED) matrix-transit methods Laser experimentPlaner elastric link mechanism Space elastric link mechanics
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一种基于模型概率单调性变化的自适应IMM-UKF改进算法 被引量:1
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作者 王平波 陈强 +2 位作者 卫红凯 贾耀君 沙浩然 《电子与信息学报》 EI CAS CSCD 北大核心 2024年第1期41-48,共8页
针对现有交互式多模型(IMM)算法模型间切换迟滞和转换速率慢的缺点,提出一种基于模型概率单调性变化的自适应交互式多模型无迹卡尔曼滤波改进算法(mIMM-UKF)。该算法利用后验信息模型概率的单调性,对马尔可夫转移概率矩阵及模型估计概... 针对现有交互式多模型(IMM)算法模型间切换迟滞和转换速率慢的缺点,提出一种基于模型概率单调性变化的自适应交互式多模型无迹卡尔曼滤波改进算法(mIMM-UKF)。该算法利用后验信息模型概率的单调性,对马尔可夫转移概率矩阵及模型估计概率进行二次修正,加快了匹配模型的切换速度及转换速率。仿真结果表明,与现有算法相比,该算法通过快速切换匹配模型,有效提高了水下目标跟踪精度。 展开更多
关键词 水下目标跟踪 IMM-UKF算法 自适应 转移概率矩阵 单调性
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基于分形理论的城市空间结构及其影响因素研究——以贵阳市为例
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作者 陈鹏 元丽娇 《信阳师范学院学报(自然科学版)》 CAS 2024年第1期88-96,共9页
以贵阳市为研究区,以2010、2020年各土地利用类型数据为基础,采用分形理论探究贵阳市土地利用的变化速度和幅度,并分析贵阳市土地空间结构变化的驱动因素。结果表明:(1)贵阳市主要以耕地和林地为主,研究期间耕地、林地、草地等农业用地... 以贵阳市为研究区,以2010、2020年各土地利用类型数据为基础,采用分形理论探究贵阳市土地利用的变化速度和幅度,并分析贵阳市土地空间结构变化的驱动因素。结果表明:(1)贵阳市主要以耕地和林地为主,研究期间耕地、林地、草地等农业用地面积下降,建设用地和水体面积增加显著。(2)研究期间贵阳市各地类分形维数相差较大,整体边界维数呈上升趋势,形态维数下降,说明城市空间结构不规则性增加,城市土地利用复杂化,紧凑性降低。(3)贵阳市土地利用类型的变化是自然、人为因素共同导致的,尤其是经济与政策的影响。 展开更多
关键词 分形理论 转移矩阵 城市空间结构
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裙带菜多糖抑制肝癌细胞增殖和迁移的机制
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作者 刘伟萍 陈建芬 +2 位作者 安金琪 罗艺 刘凤斌 《中国药理学通报》 CAS CSCD 北大核心 2024年第4期670-678,共9页
目的探讨裙带菜多糖(sulfated polysaccharide from Undaria pinnatifida,SPUP)对肝癌细胞增殖、迁移的影响及潜在机制。方法MTT和克隆形成实验检测SPUP对肝癌细胞HepG2、SMMC-7721增殖的影响;Hoechst 33258染色和Western blot法检测SPU... 目的探讨裙带菜多糖(sulfated polysaccharide from Undaria pinnatifida,SPUP)对肝癌细胞增殖、迁移的影响及潜在机制。方法MTT和克隆形成实验检测SPUP对肝癌细胞HepG2、SMMC-7721增殖的影响;Hoechst 33258染色和Western blot法检测SPUP干预后对HepG2、SMMC-7721细胞凋亡的影响;Transwell和划痕法检测HepG2、SMMC-7721细胞的迁移和侵袭;免疫荧光和Western blot法检测SPUP对肝癌细胞自噬、上皮-间质转化(epithelial-mesenchymal transition,EMT)和基质金属蛋白酶2(matrix metalloproteinase 2,MMP-2)、MMP-9蛋白的影响。结果SPUP对HepG2、SMMC-7721细胞有短期和长期的抑制增殖作用,对正常肝细胞L-02无明显抑制作用,SPUP可促进两种肝癌细胞凋亡和自噬水平。同时,SPUP可以抑制肝癌细胞的迁移侵袭能力,降低EMT和MMPs水平。结论SPUP通过促进凋亡和自噬、抑制EMT和MMPs,进而抑制肝癌细胞的增殖和迁移。 展开更多
关键词 裙带菜多糖 肝细胞癌 增殖 自噬 凋亡 侵袭迁移 上皮间质转化 基质金属蛋白酶
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基于改进自适应IMM算法的高速列车组合定位
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作者 王小敏 雷筱 张亚东 《电子与信息学报》 EI CAS CSCD 北大核心 2024年第3期817-825,共9页
针对列车高精度定位问题,该文提出基于改进自适应交互多模型(IMM)的高速列车高精度组合定位方法。首先,根据列车定位需求和各传感器特点,设计了卫星接收器、轮轴测速传感器、测速雷达以及单轴陀螺仪4种传感器的组合定位方案。然后,针对... 针对列车高精度定位问题,该文提出基于改进自适应交互多模型(IMM)的高速列车高精度组合定位方法。首先,根据列车定位需求和各传感器特点,设计了卫星接收器、轮轴测速传感器、测速雷达以及单轴陀螺仪4种传感器的组合定位方案。然后,针对IMM融合滤波算法因先验信息不准导致固定参数设置不当的问题,引入Sage-Husa自适应滤波和转移概率矩阵(TPM)自适应更新集成为自适应IMM算法。针对多模型切换的滞后问题,利用子模型似然函数值能快速反映模型变化趋势的特点,将似然函数值设为判定标志,并引入判定窗对TPM矩阵元素进行修正,有效提升了模型的切换速度。最后,基于改进自适应IMM算法对4种传感器定位信息进行融合滤波,实现高速列车的高精度组合定位。仿真结果表明:改进后的算法相比其他自适应IMM算法提升定位精度1.6%~14.7%,并且能通过提高模型间切换速度来有效降低位置误差峰值,同时具备较好的抗噪性能。 展开更多
关键词 列车定位 交互式多模型 Sage-Husa自适应滤波算法 马尔可夫转移概率矩阵 判定窗
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非齐次树上非齐次马氏链转移矩阵的一个极限性质
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作者 金少华 李慧云 +1 位作者 臧婷 贺雅萍 《高等数学研究》 2024年第1期22-24,46,共4页
通过引入样本散度的概念和构造辅助非负鞅,利用Doob鞅收敛定理给出了非齐次树上k重非齐次马氏链转移矩阵的一个极限性质.
关键词 非齐次树 马氏链 强极限定理 转移矩阵
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基于局部变分贝叶斯推断的分布式交互式多模型估计
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作者 胡振涛 杨诗博 侯巍 《控制理论与应用》 EI CAS CSCD 北大核心 2024年第4期681-690,共10页
针对目前部分多模型算法预先设定运动模型转移概率矩阵对状态估计精度的不利影响,本文提出了一种基于局部变分贝叶斯推断的分布式交互式多模型估计算法.不同于传统交互式多模型估计中运动模型转移概率矩阵为先验已知的假设条件,在分布... 针对目前部分多模型算法预先设定运动模型转移概率矩阵对状态估计精度的不利影响,本文提出了一种基于局部变分贝叶斯推断的分布式交互式多模型估计算法.不同于传统交互式多模型估计中运动模型转移概率矩阵为先验已知的假设条件,在分布融合估计框架下,首先基于最小化Kullback-Leibler散度准则的递归优化策略实现对运动模型转移概率矩阵的预测与更新;在此基础上,结合变分贝叶斯推断实现对当前时刻目标状态与模型概率的联合估计;最后依据协方差交叉融合策略完成对局部状态估计融合.仿真结果表明:新算法通过对运动模型转移概率矩阵以及模型概率自适应在线估计,有效提升了机动目标的状态估计精度. 展开更多
关键词 机动目标跟踪 变分贝叶斯推断 模型转移概率矩阵 分布式融合 协方差交叉融合
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预处理对TiB_(2)增强铝基复合材料电弧增材影响
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作者 孙焕焕 赵亮 +3 位作者 蒋鹏 刘易麟 冯鑫源 刘萍 《沈阳理工大学学报》 CAS 2024年第5期77-82,共6页
以TiB_(2)/6056铝基复合材料丝材为焊材,采用冷金属过渡焊接技术,研究TiB_(2)增强铝基复合材料丝材的电弧增材,重点分析预热处理对增材层成形及接头质量的影响。结果表明:当焊接电流为140 A、送丝速度为8 m/min、焊接速度为5 mm/s、基... 以TiB_(2)/6056铝基复合材料丝材为焊材,采用冷金属过渡焊接技术,研究TiB_(2)增强铝基复合材料丝材的电弧增材,重点分析预热处理对增材层成形及接头质量的影响。结果表明:当焊接电流为140 A、送丝速度为8 m/min、焊接速度为5 mm/s、基板预热温度为200℃时制备的增材层与基板未预热制备的增材层相比,外观成形更好,气孔数目降低,气孔尺寸减小,晶粒更细小,TiB_(2)颗粒分散更好,且增材层硬度与拉伸性能均得到了提高。 展开更多
关键词 冷金属过渡技术 电弧增材 预处理 TiB_(2)增强铝基复合材料
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公路沥青路面性能全指标预估模型研究
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作者 于丽梅 田恬 +1 位作者 果晓君 唐海翔 《北方交通》 2024年第10期26-30,34,共6页
文章基于半马尔可夫模型,利用吉林省普通公路沥青路面2017~2022年的检测数据,首先按照公路等级和养护历史进行数据分组处理,得到不同分组条件下对应的各项路面性能指标的状态转移概率,然后计算得到半马尔可夫状态转移概率矩阵库,最后建... 文章基于半马尔可夫模型,利用吉林省普通公路沥青路面2017~2022年的检测数据,首先按照公路等级和养护历史进行数据分组处理,得到不同分组条件下对应的各项路面性能指标的状态转移概率,然后计算得到半马尔可夫状态转移概率矩阵库,最后建立了基于状态转移概率矩阵的路面性能预估方程。对比结果表明,预测模型较好地表征了路面使用性能衰变规律,能够预测路面性能衰变。 展开更多
关键词 沥青路面 性能全指标预估模型 半马尔可夫模型 状态转移矩阵 路面性能预测
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基于快速评价方法的土地利用变化分析 被引量:1
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作者 周慧茹 孙晓莉 +2 位作者 任秀丽 王鑫 郑毅 《黑龙江科学》 2024年第2期41-46,50,共7页
为构建快速评价方法,及时掌握区域土地利用变化动态,促进土地资源的科学合理利用,推进自然资源可持续发展,利用影像自动分割技术,对2010年、2020年两期遥感数据进行地类信息采集,利用ArcGIS模型构建技术,采用土地利用动态变化度、地学... 为构建快速评价方法,及时掌握区域土地利用变化动态,促进土地资源的科学合理利用,推进自然资源可持续发展,利用影像自动分割技术,对2010年、2020年两期遥感数据进行地类信息采集,利用ArcGIS模型构建技术,采用土地利用动态变化度、地学信息图谱及土地利用转移矩阵等方法对研究区土地利用情况进行综合分析。结果显示,2010—2020年研究区林地面积增加244.81 hm~2,住宅用地面积增加69.68 hm~2,水域及水利设施用地面积增加33.60 hm~2;耕地和草地面积分别减少262.81 hm~2、30.71 hm~2,其他地类面积变化不大。从土地利用动态变化度来看,公共管理与公共服务用地增幅显著,达到24.62%。从地学信息图谱及土地利用转移矩阵来看,林地增加来源地类主要为耕地、园地及草地,整个研究区域均有分布,主要受到退耕还林政策及在影像分割和目视解译过程中的林下耕地影响。通过一系列研究较快地摸清了土地利用数量、布局及各地类之间相互转化的剧烈程度,可为土地利用可持续发展及相关部门开展研究提供决策依据。 展开更多
关键词 快速评价 动态变化度 转移矩阵 地学信息图谱
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