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惩罚矩阵T混合模型及其在省域经济分类中的应用
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作者 李泽安 汪钱荣 赵为华 《统计与决策》 北大核心 2025年第1期41-46,共6页
为充分考虑矩阵数据的特性和数据内部的关联性,文章基于矩阵T分布建立矩阵T混合模型及其惩罚模型来研究聚类问题。在矩阵T混合模型的似然函数上对均值矩阵分量施加自适应核范数低秩惩罚,应用ECM算法提出惩罚似然估计算法,同时提出了一... 为充分考虑矩阵数据的特性和数据内部的关联性,文章基于矩阵T分布建立矩阵T混合模型及其惩罚模型来研究聚类问题。在矩阵T混合模型的似然函数上对均值矩阵分量施加自适应核范数低秩惩罚,应用ECM算法提出惩罚似然估计算法,同时提出了一种改进的BIC模型选择准则来选择最优的混合模型数量和调节参数,进而通过自适应核范数阈值自动实现低秩估计,实现准确聚类。最后,通过数值模拟研究及与已有方法的对比验证了该方法的有用性,且将所建立的惩罚混合模型应用于中国省域经济发展水平划分研究,得到了比较准确的聚类结果。 展开更多
关键词 矩阵t分布 混合模型 自适应核范数 ECM算法 奇异值阈值
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Identification of prognostic molecular subtypes and model based on CD8+ T cells for lung adenocarcinoma
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作者 HONGMIN CAO YING XUE +3 位作者 FEI WANG GUANGYAO LI YULAN ZHEN JINGWEN GUO 《BIOCELL》 SCIE 2024年第3期473-490,共18页
Background:Cytotoxic T lymphocytes(CD8+T)cells function critically in mediating anti-tumor immune response in cancer patients.Characterizing the specific functions of CD8+T cells in lung adenocarcinoma(LUAD)could help ... Background:Cytotoxic T lymphocytes(CD8+T)cells function critically in mediating anti-tumor immune response in cancer patients.Characterizing the specific functions of CD8+T cells in lung adenocarcinoma(LUAD)could help better understand local anti-tumor immune responses and estimate the effect of immunotherapy.Methods:Gens related to CD8+T cells were identified by cluster analysis based on the single-cell sequencing data of three LUAD tissues and their paired normal tissues.Weighted gene co-expression network analysis(WGCNA),consensus clustering,differential expression analysis,least absolute shrinkage and selection operator(LASSO)and Cox regression analysis were conducted to classify molecular subtypes for LUAD and to develop a risk model using prognostic genes related to CD8+T cells.Expression of the genes in the prognostic model,their effects on tumor cell invasion,and interactions with CD8+T cells were verified by cell experiments.Results:This study defined two LUAD clusters(CD8+0 and CD8+1)based on CD8+T cells,with cluster CD8+0 being significantly associated with the prognosis of LUAD.Three heterogeneous subtypes(clusters 1,2,and 3)differing in prognosis,genome mutation events,and immune status were categorized using 42 prognostic genes.A prognostic model created based on 11 significant genes(including CD200R1,CLEC17A,ZC3H12D,GNG7,SNX30,CDCP1,NEIL3,IGF2BP1,RHOV,ABCC2,and KRT81)was able to independently estimate the death risk for patients in different LUAD cohorts.Moreover,the model also showed general applicability in external validation cohorts.Low-risk patients could benefit more from taking immunotherapy and were significantly related to the resistance to anticancer drugs.The results from cell experiments demonstrated that the expression of CD200R1,CLEC17A,ZC3H12D,GNG7,and SNX30 was significantly downregulated,while that of CDCP1,NEIL3,IGF2BP1,RHOV,ABCC2 and KRT81 was upregulated in LUAD cells.Inhibition of CD200R1 greatly increased the invasiveness of the LUAD cells,but inhibiting CDCP1 expression weakened the invasion ability of LUAD cells.Conclusion:This study defined two prognostic CD8+T cell clusters and classified three heterogeneous molecular subtypes for LUAD.A prognostic model predictive of the potential effects of immunotherapy on LUAD patients was developed. 展开更多
关键词 CD8+t cell Lung adenocarcinoma Molecular subtype Prognostic model IMMUNOtHERAPY
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T型管冷热流体混合模化方法及数值模拟验证
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作者 高清 周书华 +3 位作者 高汉武 卢涛 陈学 罗彦 《北京化工大学学报(自然科学版)》 北大核心 2025年第1期93-102,共10页
实际工程中的T型管道尺寸大、参数条件严苛,若要对其进行试验研究,所需投入较高,因此有必要对工程实际工况进行模化。采用动量比一致作为主要的相似准则,以高温导热油作为介质,建立了垂直布置的T型管道模型,保证原型与模型在温差、速度... 实际工程中的T型管道尺寸大、参数条件严苛,若要对其进行试验研究,所需投入较高,因此有必要对工程实际工况进行模化。采用动量比一致作为主要的相似准则,以高温导热油作为介质,建立了垂直布置的T型管道模型,保证原型与模型在温差、速度比、管径比上的热相似性。运用大涡模拟(LES)对原型及模型进行数值模拟验证,比较二者在温度、速度的时间分布上的相似性,结果表明原型及模型T型管内流场及温度场具有一定的相似性,利用导热油作为介质并采用动量比相似进行T型管冷热流体混合模化具有可行性。 展开更多
关键词 t型管 数值模拟 模化 导热油
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综合scRNA-Seq和Bulk RNA-Seq技术建立与肝癌CD8^(+)T细胞相关的预后模型
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作者 刘洋 池晴佳 田菲菲 《西安交通大学学报(医学版)》 北大核心 2025年第1期169-177,共9页
目的 通过单细胞测序(scRNA-Seq)和Bulk转录组测序(Bulk RNA-Seq)技术鉴定出与肝癌CD8^(+)T细胞相关的生物标志物并建立预后模型。方法 从GEO数据库中下载肝癌的单细胞数据集,通过scRNA-Seq技术提取患者与对照组间CD8^(+)T细胞的差异表... 目的 通过单细胞测序(scRNA-Seq)和Bulk转录组测序(Bulk RNA-Seq)技术鉴定出与肝癌CD8^(+)T细胞相关的生物标志物并建立预后模型。方法 从GEO数据库中下载肝癌的单细胞数据集,通过scRNA-Seq技术提取患者与对照组间CD8^(+)T细胞的差异表达基因。从TCGA数据库中下载肝癌的基因表达谱数据及临床数据,使用CIBERSORT算法、WGCNA技术筛选出与CD8^(+)T细胞具有相关性的模块基因。将差异基因与模块基因取交集基因并进行GO、KEGG分析,应用单因素COX回归分析和LASSO算法建立预后模型。通过K-M曲线和ROC曲线对模型在内、外部数据集中的预测效果进行验证。根据风险评分的中位值划分高低风险组,对高低风险组间的浸润性免疫细胞分布情况和肿瘤突变情况进行分析。结果 构建出具有9个基因的预后模型,K-M曲线及ROC曲线表明模型在内、外部数据集中均具有良好的预测能力,在高低风险组中,浸润性免疫细胞的分布情况和基因突变情况均存在显著差异。结论 本研究结合scRNA-Seq和Bulk RNA-Seq技术利用生物信息学方法开发出了一种基于CD8^(+)T细胞的新型预后模型,为肝癌患者的预后改善和生存预测提供了可靠的理论依据。 展开更多
关键词 肝癌 单细胞测序(scRNA-Seq) Bulk转录组测序(Bulk RNA-Seq) CD8^(+)t细胞 预后模型
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基于生物信息学分析PTTG1和UBE2C与肝癌预后的相关性
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作者 操利超 巴颖 +4 位作者 谌芳 徐龙 余晨笛 卢晓萍 张核子 《临床检验杂志》 2025年第1期50-58,共9页
目的利用GEO和TCGA数据库中的单细胞数据、基因表达数据和临床信息,挖掘与肝癌预后T/NK细胞相关的差异表达基因(T/NK cell-related differentially expressed genes,T/NK-DEGs),并构建肝癌预后模型。方法从GEO数据库中获得肝癌单细胞数... 目的利用GEO和TCGA数据库中的单细胞数据、基因表达数据和临床信息,挖掘与肝癌预后T/NK细胞相关的差异表达基因(T/NK cell-related differentially expressed genes,T/NK-DEGs),并构建肝癌预后模型。方法从GEO数据库中获得肝癌单细胞数据以及肝癌的基因表达矩阵。从TCGA数据库中获得肝癌基因组图谱(TCGA-LIHC)队列,其中包括mRNA表达数据、临床信息、生存信息、体细胞突变数据。基于以上数据集,通过生物信息学方法构建肝癌患者的预后模型,并预测该模型的性能。结果共鉴定出2个与肝癌预后相关的T/NK-DEGs,分别为PTTG1和UBE2C,并基于此构建了肝癌预后模型。根据风险评分,将患者分为高风险评分组和低风险评分组,其中高风险评分组患者预后明显较差。构建的肝癌预后模型在1年、3年和5年时间点的ROC曲线下面积(AUC^(ROC))分别为0.685、0.647和0.594,且较高的风险评分伴随较晚的临床分期(Ⅰ期、Ⅱ期、Ⅲ期)和T分期(T1、T2、T3),差异有统计学意义(P<0.05)。该预后模型能够预测肝癌患者的免疫细胞比例、免疫治疗和化疗药物的敏感性。结论构建的预后模型对肝癌患者的个体化生存预测和临床治疗反应具有重要的临床价值。 展开更多
关键词 肝癌 t细胞 NK细胞 生物信息学 预后模型
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尖牙反[牙合]矫治人字形和T形曲组合正畸弓丝矫治力建模 被引量:1
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作者 姜金刚 李长鹏 +2 位作者 李风潇 孙健鹏 张永德 《仪器仪表学报》 EI CAS CSCD 北大核心 2024年第7期189-199,共11页
固定矫治技术是治疗牙齿反[牙合]最为有效的矫治手段,主要通过正畸弓丝释放的矫治力来达到反[牙合]矫治中的矫治空间预留、反[牙合]牙齿回收的目的。在牙齿反[牙合]畸形中,尖牙反[牙合]是最为常见的牙齿反[牙合]畸形,常使用人字形和T形... 固定矫治技术是治疗牙齿反[牙合]最为有效的矫治手段,主要通过正畸弓丝释放的矫治力来达到反[牙合]矫治中的矫治空间预留、反[牙合]牙齿回收的目的。在牙齿反[牙合]畸形中,尖牙反[牙合]是最为常见的牙齿反[牙合]畸形,常使用人字形和T形组合曲关闭上颌牙列间隙。本文旨在正畸治疗前量化人字形和T形组合曲释放矫治力的情况,为正畸医师提供尖牙反[牙合]矫治的理论参考。分析人字形和T形组合曲的形变过程,将其形变过程分为弹性形变和弹塑性形变两类,并对两种形变下的矫治力微分方程进行了构建,将其释放的矫治力分为闭隙矫治力和倾覆矫治力两种,完成了人字形和T形组合曲理论模型的建立,其次对有限元仿真值与理论值的误差率进行计算,得到闭隙矫治力仿真值与理论值的误差率在0.43%~8.33%之间,倾覆矫治力的仿真值与理论值的误差率在2.13%~9.76%之间,搭建实验测量平台得到了闭隙矫治力实验值与理论值误差率为0%~9.30%、倾覆矫治力实验值与理论值的误差率为0%~9.76%,实验测量数据与理论值具有相同的非线性变化趋势,验证了人字形和T形组合曲理论预测模型的正确性,该模型能帮助医师在治疗前对正畸力进行详细的定量分析,从而为个性化治疗方案的制定提供依据,更好地满足患者需求。 展开更多
关键词 t形曲 人字形曲 矫治力模型 有限元仿真 矫治力测量
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HTLV-1病毒蛋白Tax对U-2 OS骨肉瘤细胞有丝分裂的影响 被引量:2
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作者 蒋贤杰 高林枫 +1 位作者 武敏 张渝君 《兰州大学学报(医学版)》 CAS 2017年第3期7-12,共6页
目的研究人1型T淋巴细胞白血病病毒(HTLV-1)所编码的病毒蛋白Tax对骨肉瘤细胞生长周期的影响。方法通过构建慢病毒表达载体在人骨肉瘤细胞株U-2 OS中表达Tax;荧光显微镜检测表达Tax所引起的骨肉瘤细胞形态和细胞分裂的变化;流式细胞方... 目的研究人1型T淋巴细胞白血病病毒(HTLV-1)所编码的病毒蛋白Tax对骨肉瘤细胞生长周期的影响。方法通过构建慢病毒表达载体在人骨肉瘤细胞株U-2 OS中表达Tax;荧光显微镜检测表达Tax所引起的骨肉瘤细胞形态和细胞分裂的变化;流式细胞方法分析表达Tax对骨肉瘤细胞周期产生的影响。结果与亲本骨肉瘤细胞比较,表达Tax的骨肉瘤细胞形态由正常的椭圆形转化为长梭形;出现了胞质分裂异常;有双核或多核细胞形成;细胞的生长周期在G2/M期发生了停滞。结论 Tax的表达破坏了骨肉瘤细胞有丝分裂的胞质分裂过程,造成异倍体现象的出现,使细胞停滞在有丝分裂的晚期。这或许是HTLV-1感染导致正常细胞转化为癌细胞的原因之一。 展开更多
关键词 人1型t淋巴细胞白血病病毒 u-2 OS骨肉瘤细胞 tAX 胞质分裂异常
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基于改进MobileNet V3的矿物智能识别模型
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作者 宛鹤 张金艳 +4 位作者 屈娟萍 张崇辉 薛季玮 王森 卜显忠 《金属矿山》 CAS 北大核心 2024年第1期174-181,共8页
针对当前矿物识别领域存在的精度不佳、适应性差、携带不便等问题,提出了一种基于改进MobileNet V3的矿物智能识别模型(CA-MobileNet V3)。为获得研究所需的有效数据集,通过由mindat. org网站和自行拍摄方式获取的矿物图像创建了一个包... 针对当前矿物识别领域存在的精度不佳、适应性差、携带不便等问题,提出了一种基于改进MobileNet V3的矿物智能识别模型(CA-MobileNet V3)。为获得研究所需的有效数据集,通过由mindat. org网站和自行拍摄方式获取的矿物图像创建了一个包含19种矿物的数据集,对其进行数据增强处理,并按照8:1:1的比例划分为训练集、验证集和测试集。为提升模型对图像信息的特征提取能力,引入协调注意力机制,用以替代轻量型MobileNet V3模型的原始SE注意力机制,以提高矿物识别准确率。最后,采用迁移学习方法预训练CA-MobileNet V3模型,以加速模型收敛、提高泛化能力、避免过拟合。在训练过程中,将CA-MobileNet V3与mobilenet v3、MobileNet V3、ShuffleNet V2、Efficient Net V2等模型进行了性能比较。结果表明:各迁移模型均展现出显著的收敛速度优势,而CA-MobileNet V3矿物智能识别模型的Top1-准确率、Top2-准确率、f_1-score值分别达到93.90%、98.58%和93.89%,在所有模型中效果最佳,且模型大小仅为4.61 MB,属于轻量化模型。为验证模型有效性,t-SNE可视化分析被用于不同模型的识别效果比较,进一步印证了CA-MobileNet V3模型的优越性。 展开更多
关键词 矿物分类 迁移学习 轻量化模型 协调注意力机制 t-SNE
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Thrust and Torque Characteristics Based on a New cutter-head Load Model 被引量:13
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作者 LIU Jianqin REN Jiabao GUO Wei 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第4期801-809,共9页
Full face rock tunnel boring machine(TBM) has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under complex geological ... Full face rock tunnel boring machine(TBM) has been widely used in hard rock tunnels, however, there are few published theory about cutter-head design, and the design criteria of cutter-head under complex geological is not clear yet. To deal with the complex relationship among geological parameters, cutter parameters, and operating parameters during tunneling processes, a cutter-head load model is established by using CSM(Colorado school of mines) prediction model. Force distribution on cutter-head under a certain geology is calculated with the new established load model, and result shows that inner cutters bear more force than outer cutters, combining with disc cutters abrasion; a general principle of disc cutters' layout design is proposed. Within the model, the relationship among rock uniaxial compressive strength(UCS), penetration and thrust on cutter-head are analyzed, and the results shows that with increasing penetration, cutter thrust increases, but the growth rate slows and higher penetration makes lower special energy(SE). Finally, a fitting mathematical model of ZT(ratio of cutter-head torque and thrust) and penetration is established, and verified by TB880 E, which can be used to direct how to set thrust and torque on cutter-head. When penetration is small, the cutter-head thrust is the main limiting factor in tunneling; when the penetration is large, cutter-head torque is the major limiting factor in tunneling. Based on the new cutter-head load model, thrust and torque characteristics of TBM further are researched and a new way for cutter-head layout design and TBM tunneling operations is proposed. 展开更多
关键词 tBM(full face rock tunnel boring machine) cutter-head load model CSM(Colorado school of mines) model cutter-head layout design t
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房地产股价波动对高技术板块的溢出效应研究——基于DGC-t-MSV模型
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作者 徐晔 谢涛 陶长琪 《运筹与管理》 CSSCI CSCD 北大核心 2024年第8期226-232,共7页
过度的金融资产投资可能导致房地产股价泡沫,并且通过风险溢出渠道给高技术板块带来价格冲击。研究聚焦于房地产行业和高技术产业的股票价格指数,结合MODWT分解和DGC-t-MSV模型进行实证分析,结果表明:其一,“房地产-高技术”的股票价格... 过度的金融资产投资可能导致房地产股价泡沫,并且通过风险溢出渠道给高技术板块带来价格冲击。研究聚焦于房地产行业和高技术产业的股票价格指数,结合MODWT分解和DGC-t-MSV模型进行实证分析,结果表明:其一,“房地产-高技术”的股票价格动态相关,房地产行业价格波动的传导作用更加强烈,对高技术板块具有明显的溢出效应;其二,实施限制性政策后房地产行业的挤出效应降低,高技术及其分类产业的创新投入受到的限制逐渐减弱;其三,短、中期频繁交易是导致房地产溢价的主要原因,需要警惕高技术板块面临的溢出风险。积极引导高技术板块的价值投资,合理配置技术要素,能够有效促进高技术产业的高质量、高水平发展。 展开更多
关键词 房地产股价波动 高技术板块 溢出效应 DGC-t-MSV模型
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基于量子衍生涡流算法和T⁃S模糊推理模型的储层岩性识别
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作者 赵娅 管玉 +1 位作者 李盼池 王伟 《石油地球物理勘探》 EI CSCD 北大核心 2024年第1期23-30,共8页
鉴于梯度下降法易陷入局部极值、普通群智能优化算法易早熟收敛,提出一种基于量子衍生涡流算法(Quantum Vortex Search Algorithm,QVSA)和T⁃S模糊推理模型的岩性识别方法,QVSA具有操作简单、收敛速度快、寻优能力强等优点,有助于T⁃S模... 鉴于梯度下降法易陷入局部极值、普通群智能优化算法易早熟收敛,提出一种基于量子衍生涡流算法(Quantum Vortex Search Algorithm,QVSA)和T⁃S模糊推理模型的岩性识别方法,QVSA具有操作简单、收敛速度快、寻优能力强等优点,有助于T⁃S模糊推理模型获得最优参数配置,从而实现储层岩性的准确识别。首先利用具有全局搜索能力的QVSA优化T⁃S模糊推理模型的各种参数;然后利用主成分分析方法降低获取的地震属性维度;再利用优化的T⁃S模糊推理模型识别储层岩性。实验结果表明,利用反映储层特征的8个地震属性识别储层岩性时,所提方法的识别正确率达到92%,比普通BP网络方法高5.1%,同时查准率、查全率、F1分数等指标也较BP网络方法提升明显。 展开更多
关键词 储层岩性识别 量子衍生涡流算法 t⁃S 模糊推理模型 模糊集 地震属性
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Bifidobacterium lactis attenuates onset of inflammation in a murine model of colitis 被引量:12
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作者 David Philippe Laurent Favre +7 位作者 Francis Foata Oskar Adolfsson Genevieve Perruisseau-Carrier Karine Vidal Gloria Reuteler Johanna Dayer-Schneider Christoph Mueller Stéphanie Blum 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第4期459-469,共11页
AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial cultur... AIM: To assess the anti-inflammatory effect of the probiotic Bifidobacterium lactis (B. lactis) in an adoptive transfer model of colitis. METHODS: Donor and recipient mice received either B. lactis or bacterial culture medium as control (deMan Rogosa Sharpe) in drinking water for one week prior to transfer of a mix of naive and regulatory T cells until sacrifice. RESULTS: All recipient mice developed signs of colonic inflammation, but a significant reduction of weight loss was observed in B. lactis-fed recipient mice compared to control mice. Moreover, a trend toward a diminution of mucosal thickness and attenuated epithelial damage was revealed. Colonic expression of pro-inflammatory and T cell markers was significantly reduced in B. lactis-fed recipient mice compared to controls. Concomitantly, forkhead box protein 3, a marker of regulatory T cells, was significantly up-regulated by B. lactis. CONCLUSION: Daily oral administration of B. lactis was able to reduce inflammatory and T cells mediators and to promote regulatory T cells specific markers in a mouse model of colitis. 展开更多
关键词 PROBIOtICS BIFIDOBACtERIUM COLItIS Adoptive transfer model Regulatory t cells INFLAMMAtION MICE
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t/k-fault diagnosis algorithm of n-dimensional hypercube network based on the MM*model 被引量:4
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作者 LIANG Jiarong ZHOU Ning YUN Long 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第1期216-222,共7页
Compared with accurate diagnosis, the system’s selfdiagnosing capability can be greatly increased through the t/kdiagnosis strategy at most k vertexes to be mistakenly identified as faulty under the comparison model,... Compared with accurate diagnosis, the system’s selfdiagnosing capability can be greatly increased through the t/kdiagnosis strategy at most k vertexes to be mistakenly identified as faulty under the comparison model, where k is typically a small number. Based on the Preparata, Metze, and Chien(PMC)model, the n-dimensional hypercube network is proved to be t/kdiagnosable. In this paper, based on the Maeng and Malek(MM)*model, a novel t/k-fault diagnosis(1≤k≤4) algorithm of ndimensional hypercube, called t/k-MM*-DIAG, is proposed to isolate all faulty processors within the set of nodes, among which the number of fault-free nodes identified wrongly as faulty is at most k. The time complexity in our algorithm is only O(2~n n~2). 展开更多
关键词 hypercube network t/k-diagnosis algorithm multiprocessor systems the Maeng and Malek(MM)* model Preparata Metze and Chien(PMC)
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Species abundance distribution models of Toona ciliata communities in Hubei Province,China 被引量:4
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作者 Yang Wang Huoming Zhou +2 位作者 Jingyong Cai Congwen Song Linzhao Shi 《Journal of Forestry Research》 SCIE CAS CSCD 2021年第1期103-117,共15页
The study of plant species abundance distribution(SAD)in natural communities is of considerable importance to understand the processes and ecological rules of community assembly.With the distribution of tree,shrub and... The study of plant species abundance distribution(SAD)in natural communities is of considerable importance to understand the processes and ecological rules of community assembly.With the distribution of tree,shrub and herb layers of eight natural communities of Toona ciliata as research targets,three diff erent ecological niche models were used:broken stick model,overlapping niche model and niche preemption model,as well as three statistical models:log-series distribution model,log-normal distribution model and Weibull distribution model,to fi t SAD of the diff erent vegetation layers based on data collected.Goodness-of-fi t was compared with Chi square test,Kolmogorov–Smirnov(K–S)test and Akaike Information Criterion(AIC).The results show:(1)based on the criteria of the lowest AIC value,Chi square value and K–S value with no signifi cant diff erence(p>0.05)between theoretic and observed SADs.The suitability and goodness-of-fi t of the broken stick model was the best of three ecological niche models.The log-series distribution model did not accept the fi tted results of most vegetation layers and had the lowest goodness-of-fi t.The Weibull distribution model had the best goodness-of-fi t for SADs.Overall,the statistical SADs performed better than the ecological ones.(2)T.ciliata was the dominant species in all the communities;species richness and diversity of herbs were the highest of the vegetation layers,while the diversities of the tree layers were slightly higher than the shrub layers;there were fewer common species and more rare species in the eight communities.The herb layers had the highest community evenness,followed by the shrub and the tree layers.Due to the complexity and habitat diversity of the diff erent T.ciliata communities,comprehensive analyses of a variety of SADs and tests for optimal models together with management,are practical steps to enhance understanding of ecological processes and mechanisms of T.ciliata communities,to detect disturbances,and to facilitate biodiversity and species conservation. 展开更多
关键词 toona ciliata community tree-shrubherb layers Niche models Statistical models Species abundance distribution(SAD) model fi t
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海洋石油工程固定式导管架平台T/K/Y节点马鞍口建模
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作者 林永章 柳冉 +2 位作者 翟志国 王伟 袁杰 《金属加工(热加工)》 2024年第6期73-76,共4页
海洋石油工程固定式导管架是海上油气资源开采的重要设施,是由钢管相贯焊接形成的空间桁架结构。导管架的主要焊接结构是T/K/Y节点,T/K/Y节点中存在大量的马鞍口结构。目前,对马鞍口的加工及焊接主要以二维图样贴片为主,尚无软件可实现... 海洋石油工程固定式导管架是海上油气资源开采的重要设施,是由钢管相贯焊接形成的空间桁架结构。导管架的主要焊接结构是T/K/Y节点,T/K/Y节点中存在大量的马鞍口结构。目前,对马鞍口的加工及焊接主要以二维图样贴片为主,尚无软件可实现管节点马鞍口的参数化三维建模。在分析马鞍口相贯线机理的基础上,建立马鞍口相贯线的数学模型,并基于此利用Unity3D编写了绘制马鞍口相贯线的通用软件,实现了马鞍口的参数化三维建模,有效解决了实际生产中T/K/Y节点马鞍口难以建模的问题,为管节点马鞍口的加工及智能焊接提供精确的模型。 展开更多
关键词 t/K/Y节点 马鞍口 参数化建模
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Dynamic modeling of a parafoil system considering flap deflection 被引量:4
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作者 Tao Jin Sun Qinglin +1 位作者 Chen Zengqiang He Yingping 《Journal of Southeast University(English Edition)》 EI CAS 2017年第4期416-425,共10页
In order to better study the dynamic characteristics and the control strategy of parafoil systems,considering the effect of flap deflection as the control mechanism and regarding the parafoil and the payload as a rigi... In order to better study the dynamic characteristics and the control strategy of parafoil systems,considering the effect of flap deflection as the control mechanism and regarding the parafoil and the payload as a rigid body,a six degrees-of-freedom(DOF)dynamic model of a parafoil system including three DOF for translational motion and three DOF for rotational motion,is established according to the K rchhoff motion equation.Since the flexible winged paafoil system flying at low altitude is more susceptibleto winds,the motion characteristics of the parafoil system Wth and Wthout winds are simulated and analyzed.Furthermore,the ardropm test is used to further verify the model.The comparison results show that the simulation trajectory roughly overlaps with the actual flight track.The horzontnl velocity of the simulation model is in good accordance with the airdrop test,with a deviation less than0.5m/s,while its simulated vertical velocity fuctuates slightly under the infuence of the wind,and shows a similar trend to the ardrop test.It is concludedthat the established model can well describe the characteristics of the parafoil system. 展开更多
关键词 parafoil system dynamic modeling and simulation fig h t chaacterstic airdrop experiment fap defection
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基于T态模型的课程考核方案改进与实践
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作者 付非 唐琳 张慧锋 《科学咨询》 2024年第20期26-29,共4页
课程考核方案的T态模型从两个维度提升考核设计:横向的要素设计维度,即学习者知识、能力及素质在考核中均有衡量;纵向思考深度,逻辑的价值递进性。管理沟通课程考核方案的改进以T态模型为框架,旨在提升课程的“高阶性”与“挑战度”。... 课程考核方案的T态模型从两个维度提升考核设计:横向的要素设计维度,即学习者知识、能力及素质在考核中均有衡量;纵向思考深度,逻辑的价值递进性。管理沟通课程考核方案的改进以T态模型为框架,旨在提升课程的“高阶性”与“挑战度”。通过建立“目标导向”试题库,构建网络教学资源库、建立阶段性考核方案、构建线上线下结合的立体考核模式来进行考核的改进。具体实施的过程中,课前布置、课中投票问答、课后测验和期末测试均围绕增强应用性、灵活性的原则,构建丰富性、反思性强的考核体系。实施效果表明新的考核方案能够提高学习者参与度和学习积极性,有助于培养学习者终身学习的习惯、提升团队协作与解决复杂问题的能力,形成了横纵交织的课程考核结构,横联纵进效应的高品质、目标导向的整体考核。 展开更多
关键词 t态模型 管理沟通 考核方案 改进 课程 实践 医药院校
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S-T-S混合式循环互助教学模式用于少学时“化工原理”课程
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作者 吕玲 《教育教学论坛》 2024年第31期157-160,共4页
“化工原理”课程是化工及相关专业的专业基础课程,相关专业的学时少,课程难,需重点解决的问题是“三多”“三不愿”“三不明”。针对痛点问题,提出了线上线下混合式循环互助的创新设计思路,包括:教师帮助学生自制课前、课中、课后习题... “化工原理”课程是化工及相关专业的专业基础课程,相关专业的学时少,课程难,需重点解决的问题是“三多”“三不愿”“三不明”。针对痛点问题,提出了线上线下混合式循环互助的创新设计思路,包括:教师帮助学生自制课前、课中、课后习题,学生帮助教师反馈真实学习情况,学生帮助学生组团互助学习。问卷调查和评教结果显示,在一定程度上解决了“三多”“三不愿”的问题;通过建立“助教团队”反馈不同层次学生的学习情况,较好地解决了“三不明”的问题。学生的成绩与教改前相比有明显提高。 展开更多
关键词 线上线下 S-t-S教学模式 化工原理 痛点问题
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Development of a novel rat model of heterogeneous hepatic injury by injection with colchicine via the splenic vein 被引量:2
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作者 Yan-Yan Zhang Chao-Xu Zhang +6 位作者 Yu Li Xuan Jiang Yong-Fang Wang Yang Sun Jun Wang Wan-Ying Ji Yi Liu 《World Journal of Gastroenterology》 SCIE CAS 2018年第44期5005-5012,共8页
AIM To develop a novel rat model of heterogeneous hepatic injury.METHODS Seventy male Sprague-Dawley rats were randomly divided into a control group(n = 10) and a colchicine group(n =60). A 0.25% colchicine solution(0... AIM To develop a novel rat model of heterogeneous hepatic injury.METHODS Seventy male Sprague-Dawley rats were randomly divided into a control group(n = 10) and a colchicine group(n =60). A 0.25% colchicine solution(0.4 mL/kg) was injected via the splenic vein in the colchicine group to develop a rat model of heterogeneous hepatic injury. An equal volume of normal saline was injected via the splenic vein in the control group. At days 3, 7, and 14 and weeks 4, 8, and 12 after the operation, at least seven rats of the colchicine group were selected randomly for magnetic resonance imaging(MRI) examinations, and then they were euthanized. Ten rats of the control group underwent MRI examinations at the same time points, and then were euthanized at week 12. T2-weighted images(T2 WI) and diffusion weighted imaging(DWI) were used to evaluate the heterogeneous hepatic injury. The heterogeneous injury between the left and right hepatic lobes was assessed on liver sections according to the histological scoring criteria, and correlated with the results of MRI study. RESULTS Obvious pathological changes occurred in the hepatic parenchyma in the colchicine group. Hepatic injury scores were significantly different between the left and right lobes at each time point(P < 0.05). There was a significant difference in apparent diffusion coefficient(ADC) of DWI and liver-to-muscle ratio(LMR) of T2 WI between the left and right lobes of rats in the colchicine group(P < 0.05) at each time point, and similar results were observed between the colchicine and control groups. Besides, there was a significant correlation between hepatic injury scores and ADC values or LMR(r =-0.682, P = 0.000; r =-0.245, P = 0.018).CONCLUSION Injection with colchicine via the splenic vein can be used to successfully develop a rat model of heterogeneous hepatic injury. DWI and T2 WI may help evaluate the heterogeneous injury among liver lobes. 展开更多
关键词 Heterogeneous hepatic injury Rat model COLCHICINE t2-weighted images Diffusion weighted imaging
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Comparing the model forms estimating generalised diameter-height re-lationships in Tecomella undulata plantations in hot arid region of India 被引量:1
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作者 Vindhya Prasad Tewari 《Journal of Forestry Research》 SCIE CAS CSCD 2007年第4期255-260,共6页
Four generalised diameter-height equations were developed and compared for pure and even-aged stands of Tecomella undulata in hot arid region of Rajasthan State in India. The data used to fit the equations consisted o... Four generalised diameter-height equations were developed and compared for pure and even-aged stands of Tecomella undulata in hot arid region of Rajasthan State in India. The data used to fit the equations consisted of 1 540 diameter-height observations collected from the plots laid out in uniformly stocked stands of varying age and density. The performance of four equations was tested by non-linear least squares regression and evaluated using different statistical criteria. Finally, these equations, with the same values of coefficients ob- tained during the fitting phase, were validated by an independent data set consisting of 854 diameter-height observations. Overall, equation (4) (Hui and Gadow function) was found to perform best for both the fitting data set as well as validation data set. 展开更多
关键词 Generalised height-diameter equations t. undulata model evaluation validation Hot desert INDIA
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