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连铸方坯直接轧制温度场及产品性能研究 被引量:10
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作者 郝晋阳 冯光宏 张宏亮 《钢铁钒钛》 CAS 北大核心 2016年第3期119-123,共5页
直接轧制连铸坯切断后直接进入粗轧,没有加热炉加热过程,导致连铸坯温度场不均匀。通过有限元法对直接轧制连铸坯进粗轧机前的温度场以及直接轧制和传统轧制第一道次形变进行了数值模拟,结果表明:150 mm×150 mm连铸坯切断及之后的3... 直接轧制连铸坯切断后直接进入粗轧,没有加热炉加热过程,导致连铸坯温度场不均匀。通过有限元法对直接轧制连铸坯进粗轧机前的温度场以及直接轧制和传统轧制第一道次形变进行了数值模拟,结果表明:150 mm×150 mm连铸坯切断及之后的300 s内,连铸坯总体温度保持1 000℃以上的较高温度,可以实现直接轧制;直接轧制心部形变比传统轧制大,连铸坯心部比表面温度高,心表温差大有利于形变的渗透。进行了方坯直接轧制现场试验,验证了温度场模拟结果,同时对产品力学性能及时效进行试验,结果表明:方坯直接轧制连铸坯不均匀温度场导致了连铸坯各部位对应产品的性能差异;经时效试验,产品抗拉强度和屈服强度在20 MPa范围波动,变化的趋势不明显,断后延伸率在时效的前10天有明显升高。 展开更多
关键词 连铸方坯 直接轧制 温度场 力学性能 时效试验
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QSTE700型冷弯高强度钢方管的冷作硬化效应 被引量:9
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作者 晁灿 赵亦希 +2 位作者 康稳 晏培杰 马跃峰 《上海交通大学学报》 EI CAS CSCD 北大核心 2014年第5期605-609,共5页
针对直接成方冷弯QSTE700型高强度钢方管的直边和角部进行单向拉伸试验,分析了其不同部位的力学性能,并将试验结果与普碳钢方管进行对比.结果表明:成形后,高强度钢方管直边部分的屈服强度和抗拉强度的增幅不大,焊缝区域的屈服强度提高了... 针对直接成方冷弯QSTE700型高强度钢方管的直边和角部进行单向拉伸试验,分析了其不同部位的力学性能,并将试验结果与普碳钢方管进行对比.结果表明:成形后,高强度钢方管直边部分的屈服强度和抗拉强度的增幅不大,焊缝区域的屈服强度提高了约10%;方管角部的屈服强度平均增幅为17.78%,明显低于普碳钢方管角部屈服强度的增幅,角部屈服强度的提高与实际的成形圆角有关.同时,将方管分为直边区和角部区,分别赋予材料真实力学性能参数进行有限元模拟,所得结果比均匀化材质更接近于真实情况. 展开更多
关键词 高强度钢 方管 冷弯成形 单向拉伸试验 冷作硬化
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方钢管覆板及竖向插板加强T形节点受压静力试验 被引量:9
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作者 常鸿飞 夏军武 +1 位作者 段晓牧 戚豹 《建筑结构学报》 EI CAS CSCD 北大核心 2013年第10期57-63,共7页
为分析方钢管加强节点的轴压承载能力和破坏模式,对支管与主管宽度比β=0.4和β=0.8的两组覆板加强节点、竖向插板加强节点进行轴向静力加载试验。分析了节点破坏模式、荷载-位移曲线、主管变形及应变,以及加强节点的受压承载机理。结... 为分析方钢管加强节点的轴压承载能力和破坏模式,对支管与主管宽度比β=0.4和β=0.8的两组覆板加强节点、竖向插板加强节点进行轴向静力加载试验。分析了节点破坏模式、荷载-位移曲线、主管变形及应变,以及加强节点的受压承载机理。结果表明:在支管轴向压力作用下,未加强及加强节点的变形能力都较好,试件在破坏前有充分的塑性发展;覆板及插板加强节点的受压承载能力较对应的未加强试件有显著提高,当β=0.4时加强节点的破坏模式与未加强节点一致,当β=0.8时存在节点过度加强问题,引起支管先于节点破坏;相同β下,覆板加强节点的受压承载力高于竖向插板加强节点;在主管表面屈服破坏控制的情况下,覆板加强节点的承载机理为覆板与主管上翼缘共同屈服,竖向插板加强节点的承载机理为插板扩大了主管上、下翼缘的屈服范围。 展开更多
关键词 方钢管 覆板加强节点 竖向插板加强节点 静力试验 受压承载能力
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基于随机森林模型的古代玻璃主成分鉴定及分类 被引量:2
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作者 肖锦娟 庞金祥 陈文卓 《科学技术创新》 2023年第14期37-40,共4页
本文主要研究了古代玻璃制品的成分分析与鉴别问题。选取相关数据,对缺失值处理和异常数据剔除后,进行定类与定类之间关系分析,选择差异性分析中的卡方检验判断玻璃表面风化与纹饰、颜色、类型之间的关系,再使用多独立样本Kruskal-Walli... 本文主要研究了古代玻璃制品的成分分析与鉴别问题。选取相关数据,对缺失值处理和异常数据剔除后,进行定类与定类之间关系分析,选择差异性分析中的卡方检验判断玻璃表面风化与纹饰、颜色、类型之间的关系,再使用多独立样本Kruskal-Wallis和单因素方差分析进行显著性差异判断,得到相应的统计规律。并依据风化点检测数据,建立基于参数检验和非参数检验的化学成分预测模型,并将数据合并处理后采用随机森林对高钾玻璃和铅钡玻璃分类规律进行分析,根据玻璃利用类别,利用主成分分析法进行玻璃的亚类划分。再根据得到的载荷矩阵热力图结合因子载荷象限,并进行降维处理,得到最终的划分结果。 展开更多
关键词 古代玻璃 随机森林 卡方检验 化学成分 参数检验
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钢管杆方形法兰受弯性能试验研究与有限元分析 被引量:6
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作者 邓洪洲 高英赫 +1 位作者 张亮亮 金晓华 《建筑结构学报》 EI CAS CSCD 北大核心 2014年第7期44-52,共9页
为研究双杆输电钢管杆中方形刚性法兰的受力性能,对2组6个方形刚性法兰试件进行了静力加载试验,并对方形法兰节点进行了非线性有限元分析。对法兰板、肋板及螺栓的受力分析结果表明,试验结果与有限元分析结果具有较好的一致性。参考现... 为研究双杆输电钢管杆中方形刚性法兰的受力性能,对2组6个方形刚性法兰试件进行了静力加载试验,并对方形法兰节点进行了非线性有限元分析。对法兰板、肋板及螺栓的受力分析结果表明,试验结果与有限元分析结果具有较好的一致性。参考现行规范中圆形刚性法兰的设计方法,设计方形刚性法兰的法兰板和肋板是安全的,但计算方形法兰节点的螺栓受力则偏于不安全,螺栓实际受力为拉弯应力状态。法兰板刚度不均匀会导致个别螺栓受力过大,推荐采用切角形法兰板和在钢管上下翼缘板中间布置通长外肋的方式来减小螺栓受力的不均匀性。提出以第2排螺栓中心连线作为方形刚性法兰在弯矩作用下的旋转轴,此时最大受拉螺栓轴力较现行规范计算结果增大20%,与试验和有限元分析结果接近。 展开更多
关键词 钢管杆 方形法兰 刚性法兰 静力试验 有限元分析 受弯性能
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水流强度对淹没式方桩局部冲刷特性的影响
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作者 杜升涛 王超琳 +2 位作者 杨博 王振鲁 梁丙臣 《河海大学学报(自然科学版)》 CAS CSCD 北大核心 2024年第2期92-100,共9页
为研究不同水流强度作用下淹没式方桩的局部冲刷特性及流场变化,开展了非均匀沙条件下的桩基局部冲刷试验,分析了桩周的冲刷地形、冲刷深度变化规律;利用OpenFOAM对不同水流强度下的桩周流场进行了模拟,讨论了桩前马蹄涡、桩周回流和下... 为研究不同水流强度作用下淹没式方桩的局部冲刷特性及流场变化,开展了非均匀沙条件下的桩基局部冲刷试验,分析了桩周的冲刷地形、冲刷深度变化规律;利用OpenFOAM对不同水流强度下的桩周流场进行了模拟,讨论了桩前马蹄涡、桩周回流和下降水流的分布特点。结果表明:在清水冲刷条件下,桩周的冲刷坑深度、沙丘高度和受冲刷影响区域大小均随水流强度的增大而增大;在平衡冲刷地形下,高水流强度冲刷后桩周流动更加复杂,冲刷坑内的涡流强度大幅度提高;当水流强度接近1时,粗颗粒泥沙对细颗粒的屏蔽效应会在一定程度上影响桩周最大冲刷深度。 展开更多
关键词 方桩 局部冲刷 水流强度 流场特性 模型试验 OPENFOAM
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Association between people’s attitudes towards human-elephant conflict and their locational,demographic,and socio-economic characteristics in Buxa Tiger Reserve and its adjoining area,India
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作者 Chiranjib NAD Tamal BASU-ROY 《Regional Sustainability》 2024年第1期11-25,共15页
“Human-elephant conflict(HEC)”,the alarming issue,in present day context has attracted the attention of environmentalists and policy makers.The rising conflict between human beings and wild elephants is common in Bu... “Human-elephant conflict(HEC)”,the alarming issue,in present day context has attracted the attention of environmentalists and policy makers.The rising conflict between human beings and wild elephants is common in Buxa Tiger Reserve(BTR)and its adjoining area in West Bengal State,India,making the area volatile.People’s attitudes towards elephant conservation activity are very crucial to get rid of HEC,because people’s proximity with wild elephants’habitat can trigger the occurrence of HEC.The aim of this study is to conduct an in-depth investigation about the association of people’s attitudes towards HEC with their locational,demographic,and socio-economic characteristics in BTR and its adjoining area by using Pearson’s bivariate chi-square test and binary logistic regression analysis.BTR is one of the constituent parts of Eastern Doors Elephant Reserve(EDER).We interviewed 500 respondents to understand their perceptions to HEC and investigated their locational,demographic,and socio-economic characteristics including location of village,gender,age,ethnicity,religion,caste,poverty level,education level,primary occupation,secondary occupation,household type,and source of firewood.The results indicate that respondents who are living in enclave forest villages(EFVs),peripheral forest villages(PFVs),corridor village(CVs),or forest and corridor villages(FCVs),mainly males,at the age of 18–48 years old,engaged with agriculture occupation,and living in kancha and mixed houses,have more likelihood to witness HEC.Besides,respondents who are illiterate or at primary education level are more likely to regard elephant as a main problematic animal around their villages and refuse to participate in elephant conservation activity.For the sake of a sustainable environment for both human beings and wildlife,people’s attitudes towards elephants must be friendly in a more prudent way,so that the two communities can live in harmony. 展开更多
关键词 Human-elephant conflict Elephant conservation Chi-square test statistics Binary logistic regression Demographic and socioeconomic characteristics Buxa Tiger Reserve
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基于多元线性回归预测模型的sensor态势研究 被引量:6
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作者 张俭鸽 李颖颖 《计算机技术与发展》 2011年第9期229-232,共4页
由于系统漏洞层出不穷,网络管理员也不容易获得用户主机的安全态势,如何在攻击者利用漏洞之前,对网络中用户主机的漏洞、脆弱性进行自动发现成为保障计算机网络安全、平稳运行的关键问题。文中针对多元线性回归预测模型算法,首先利用最... 由于系统漏洞层出不穷,网络管理员也不容易获得用户主机的安全态势,如何在攻击者利用漏洞之前,对网络中用户主机的漏洞、脆弱性进行自动发现成为保障计算机网络安全、平稳运行的关键问题。文中针对多元线性回归预测模型算法,首先利用最小二乘法实现对多元线性回归方程的求解,然后利用"t-检验"检验回归系数的显著性,实现对sensor安全的精确预测,使网络管理员能直观了解到sensor的全状况,以寻求最低的事故率、最少的损失和最优的安全投资效益。 展开更多
关键词 漏洞 安全态势 多元线性回归预测模型 最小二乘法 t-检验
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Correlation knowledge extraction based on data mining for distribution network planning 被引量:1
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作者 Zhifang Zhu Zihan Lin +4 位作者 Liping Chen Hong Dong Yanna Gao Xinyi Liang Jiahao Deng 《Global Energy Interconnection》 EI CSCD 2023年第4期485-492,共8页
Traditional distribution network planning relies on the professional knowledge of planners,especially when analyzing the correlations between the problems existing in the network and the crucial influencing factors.Th... Traditional distribution network planning relies on the professional knowledge of planners,especially when analyzing the correlations between the problems existing in the network and the crucial influencing factors.The inherent laws reflected by the historical data of the distribution network are ignored,which affects the objectivity of the planning scheme.In this study,to improve the efficiency and accuracy of distribution network planning,the characteristics of distribution network data were extracted using a data-mining technique,and correlation knowledge of existing problems in the network was obtained.A data-mining model based on correlation rules was established.The inputs of the model were the electrical characteristic indices screened using the gray correlation method.The Apriori algorithm was used to extract correlation knowledge from the operational data of the distribution network and obtain strong correlation rules.Degree of promotion and chi-square tests were used to verify the rationality of the strong correlation rules of the model output.In this study,the correlation relationship between heavy load or overload problems of distribution network feeders in different regions and related characteristic indices was determined,and the confidence of the correlation rules was obtained.These results can provide an effective basis for the formulation of a distribution network planning scheme. 展开更多
关键词 Distribution network planning Data mining Apriori algorithm Gray correlation analysis Chi-square test
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Screening influencing factors of blood stasis constitution in traditional Chinese medicine 被引量:3
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作者 ZHOU Xiaoying YANG Shengwen +3 位作者 OU Jintao WANG Zhuo WANG Guangrong LUO Yue 《Digital Chinese Medicine》 2022年第2期169-177,共9页
Objective To study the influencing factors of blood stasis constitution and provide a basis for treating blood stasis-related diseases by traditional Chinese medicine(TCM) constitution identification.Methods Data were... Objective To study the influencing factors of blood stasis constitution and provide a basis for treating blood stasis-related diseases by traditional Chinese medicine(TCM) constitution identification.Methods Data were collected using the self-developed TCM constitution identification platform based on B/S model by the project team. The obtained data were divided into blood stasis constitution and normal constitution groups. The differences of the categorical type influencing factors(gender, birth mode, feeding mode within four months of birth, family history, marital status, eating habits, sleeping habits, exercise habits, emotional state, stress situation, and living environment) and the quantitative type influencing factors(sleep time, age,and mother’s age at birth) on the constitution of the two groups were analyzed. In the singlefactor analysis, the Pearson’s chi-square test was selected for the categorical variable, and the independent sample t test and Mann-Whitney U nonparametric test were selected for the quantitative variables according to whether they conformed to the positive-terrestrial distribution;the binary logistic stepwise regression method was selected for the multi-factor analysis.Results The data of 318 cases were collected from the TCM composition identification platform, and 159 cases of blood stasis constitution were used as the experimental group and 159 cases of normal constitution were used as the control group. The Pearson’s chi-square test yielded significant differences(P < 0.05) in the effects of gender, pressure situation, family history, living environment, emotional state, exercise habits, and dietary habits on blood stasis constitution. The independent samples t test yielded differences in sleep duration between the blood stasis constitution and normal constitution populations(P < 0.05), which meant sleep duration of the blood stasis constitution population was less than that of the normal constitution population. The Mann-Whitney U nonparametric test results accepted the o 展开更多
关键词 Blood stasis constitution Screening influencing factors Pearson’s chi-square test Nonparametric test Binary logistic stepwise regression
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有限深度均匀水流中方柱阻力测试研究 被引量:4
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作者 邓绍云 邱清华 《红水河》 2009年第3期42-47,共6页
为解决工程实际中方柱桩基码头与桥墩的水流绕流阻力计算问题,以指导涉及方柱桩基的物理模型试验和数值模拟计算等工作,在归纳总结已有的研究成果的基础上,通过先进的测力设备,对有限深度均匀水流中方柱绕流进行了阻力测试研究,进一步... 为解决工程实际中方柱桩基码头与桥墩的水流绕流阻力计算问题,以指导涉及方柱桩基的物理模型试验和数值模拟计算等工作,在归纳总结已有的研究成果的基础上,通过先进的测力设备,对有限深度均匀水流中方柱绕流进行了阻力测试研究,进一步掌握其特性规律,并指出今后研究方向。 展开更多
关键词 有限深度均匀水流 方柱 绕流 阻力特性 试验
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钢箱模块叠合方钢管梁受弯性能试验与参数分析
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作者 常鸿飞 胡磊 +3 位作者 宋心怡 秦福阳 安爱臣 张少华 《中国矿业大学学报》 EI CAS CSCD 北大核心 2023年第3期540-549,共10页
为解决叠箱模块化钢结构体系模块间约束较弱的问题,提出上下模块方钢管梁叠合受力的连接方法,通过试验与有限元参数分析研究了简支叠合钢梁的受弯性能,考察了连接位置、螺栓数量、钢梁尺寸等因素的影响.试验结果表明:试验构件出现2种典... 为解决叠箱模块化钢结构体系模块间约束较弱的问题,提出上下模块方钢管梁叠合受力的连接方法,通过试验与有限元参数分析研究了简支叠合钢梁的受弯性能,考察了连接位置、螺栓数量、钢梁尺寸等因素的影响.试验结果表明:试验构件出现2种典型破坏模式,即钢梁屈服和连接件剪切破坏;抗剪连接可阻止上下梁间的滑移,有效提高叠合钢梁的受弯性能,强连接叠合梁抗弯承载力比无连接叠合梁提高了26.67%,初始抗弯刚度提高了70.65%.参数分析表明:随弯剪段螺栓数量增加,叠合梁的受弯性能比无连接叠合梁有明显提升;每个弯剪段连接处各设置4个直径20 mm的螺栓,且连接板长、板厚分别为240 mm,8 mm时,上下梁间有较好的协同受弯性能.叠合钢梁协同受弯机理为:叠合梁间的抗剪连接阻止了上下梁间相对滑移,对上梁产生偏心压力,对下梁产生偏心拉力.随着连接作用的增强,上下梁的中和轴均趋近叠合面,从而使上梁呈现压弯受力的特征,下梁则呈现拉弯受力的特征. 展开更多
关键词 钢箱模块 方钢管 叠合钢梁 受弯性能 试验 参数分析
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方捆打捆机草捆动态称重试验台设计与试验 被引量:4
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作者 高国民 郭辉 +3 位作者 吕全贵 郝良军 刘希光 刘家君 《农机化研究》 北大核心 2020年第4期139-144,共6页
为实时监测方捆打捆机作业过程中各草捆质量,实现方捆机草捆随车动态称重系统的测试,设计并搭建了以STM32单片机为核心控制器的动态称重试验台。通过对方草捆称重过程及两组称重的数据分析,获得了称重值变化规律。针对此变化规律确定了... 为实时监测方捆打捆机作业过程中各草捆质量,实现方捆机草捆随车动态称重系统的测试,设计并搭建了以STM32单片机为核心控制器的动态称重试验台。通过对方草捆称重过程及两组称重的数据分析,获得了称重值变化规律。针对此变化规律确定了草捆质量检测方法,用格拉布斯准则将称重异常数据点剔除,并对剩余称重值中相邻3个称重值取平均,选取所有平均值中最大值作为此草捆质量检测值。运用SPSS软件对多组不同质量草捆检测值与实际值进行曲线回归,获得草捆质量检测值与实际值回归方程,并测试此回归方程拟合效果。结果表明:回归方程可有效拟合草捆质量检测值与实际值的关系(R^2=0.998,Sig<0.05);称重系统能有效对方草捆质量进行动态监测,监测误差小于3%,可为方捆打捆机草捆随车动态称重系统提供理论依据。 展开更多
关键词 草捆 打捆机 动态称重 试验台
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烧杯搅拌试验条件的最优化 被引量:3
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作者 张延风 《企业技术开发》 2014年第4期44-45,共2页
烧杯搅拌试验是水厂合理确定混凝剂投加量的重要方法,文章选用新型有机玻璃方形烧杯,利用正交试验对南郊水厂烧杯搅拌试验条件进行最优筛选,同时,结合生产工艺及G值,提出了处理黑河水质时烧杯搅拌试验的最优化试验条件。
关键词 黑河水质 烧杯搅拌试验 方形烧杯 正交试验
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Propagation Model Optimization Based on Ion Motion Optimization Algorithm for Efficient Deployment of eLTE Network
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作者 Deussom Djomadji Eric Michel Tsague Njatsa Austene Beldine Tonye Emmanuel 《Journal of Computer and Communications》 2022年第11期171-196,共26页
Propagation models are the foundation for radio planning in mobile networks. They are widely used during feasibility studies and initial network deployment, or during network extensions, particularly in new cities. Th... Propagation models are the foundation for radio planning in mobile networks. They are widely used during feasibility studies and initial network deployment, or during network extensions, particularly in new cities. They can be used to calculate the power of the signal received by a mobile terminal, evaluate the coverage radius, and calculate the number of cells required to cover a given area. This paper takes into account the standard K factors model and then uses the Ion motion optimization (IMO) algorithm to set up a propagation model adapted to the physical environment of each of the Cameroonian cities of Yaoundé and Bertoua for different frequencies and technologies. Drive tests were made on the CDMA network in the city of Yaoundé on one hand and on an LTE TDD network in the city of Bertoua on the other hand. IMO is used as the optimization algorithm to deduct a propagation model which fits the environment of the two considered towns. The calculation of the root-mean-square error (RMSE) between the actual data from the drive tests and the prediction data from the implemented model allows the validation of the obtained results. A comparative study made between the RMSE value obtained by the new model and those obtained by the Okumura-Hata and K factors standard models, allowed us to conclude that the new model obtained in each of these two cities is better and more representative of our local environment than the Okumura-Hata currently implemented. The implementation shows that IMO can perform well and solve this kind of optimization problem;the newly obtained models can be used for radio planning in the cities of Yaounde and Bertoua in Cameroon. 展开更多
关键词 Drive test IMO Propagation Models Root Mean square Error
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On the Different Ways to Handle the Trend of Disease Risk in Genetic Association Tests
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作者 Tapati Basak 《Open Journal of Statistics》 2022年第4期521-531,共11页
Genetic association studies usually apply the simple chi-square (χ<sup>2</sup>)-test for testing association between a single-nucleotide polymorphism (SNP) and a particular phenotype, assuming the genotyp... Genetic association studies usually apply the simple chi-square (χ<sup>2</sup>)-test for testing association between a single-nucleotide polymorphism (SNP) and a particular phenotype, assuming the genotypes and phenotypes are independent. So, the conventional χ<sup>2</sup>-test does not consider the increased risk of an individual carrying the increasing number of disease responsible allele (a particular genotype). But, the association tests should be performed with the consideration of this disease risk according to the mode of inheritance (additive, dominant, recessive). Practical demonstration of the two possible methods for considering such order or trends in contingency tables of genetic association studies using SNP genotype data is the purpose of this paper. One method is by pooling the genotypes, and the other is scoring the individual genotypes, based on the disease risk according to the inheritance pattern. The results show that the p-values obtained from both the methods are similar for the dominant and recessive models. The other important features of the methods were also extracted using the SNP genotype data for different inheritance patterns. 展开更多
关键词 Association CHI-square Trend test SNP GENOTYPE
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方立柱水压机动态测试分析 被引量:2
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作者 左虹 官英平 +1 位作者 刘国权 史哲 《锻压技术》 CAS CSCD 北大核心 1995年第1期48-51,共4页
本文对改造后的水压机进行了动态测试分析,并与理论计算进行了比较,得出的结论对生产实际中的机器技术改造有重要指导意义。
关键词 立柱 位移 测试 水压机 锻压设备
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Epidemiological Characteristics of Influenza A and B in Macao,2010–2018 被引量:2
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作者 HoiMan Ng Teng Zhang +9 位作者 Guoliang Wang SiMeng Kan Guoyi Ma Zhe Li Chang Chen Dandan Wang MengIn Wong ChioHang Wong Jinliang Ni Xiaohua Douglas Zhang 《Virologica Sinica》 SCIE CAS CSCD 2021年第5期1144-1153,共10页
Influenza is one of the major respiratory diseases in humans.Macao is a tourist city with high density of population and special population mobility.The study on the epidemiological characteristics of influenza in Mac... Influenza is one of the major respiratory diseases in humans.Macao is a tourist city with high density of population and special population mobility.The study on the epidemiological characteristics of influenza in Macao should bring great value for preventing influenza in tourist cities like Macao in the world.In this study,we collected a total of 104,874 samples with influenza-like illness(ILI)in Macao from 2010 to 2018.Chi-square test and binary multivariable logistic regression were used to investigate the epidemiological characteristics of influenza A and B in Macao.Among these ILI samples,the overall positive rate is 17.17%for influenza A and 6.97%for influenza B.The epidemics of influenza in three years(i.e.,2012,2017 and 2018)differ from the remaining years(i.e.,normal years).In a normal year,influenza A occurs year-round whereas influenza B is seasonal.Our research shows significant differences in influenza infections between different age groups in normal years.Interestingly,our analysis shows no significant difference between locals and tourists in influenza A and B infection in a normal year,whereas the odds of influenza A in tourists were significantly higher than those in locals in July 2017 and the odds of influenza B in tourists were significantly higher than those in locals in January–February 2012 and January–February 2018.This is possibly attributed by the policy of free vaccination to everyone in Macao.These findings should be valuable for preventing influenza in not only Macao but also the world. 展开更多
关键词 INFLUENZA EPIDEMIOLOGY Chi-square test Logistic regression MACAO
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航空发动机试飞数据野值识别与补正算法 被引量:2
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作者 左思佳 李卢丹 《机械研究与应用》 2019年第3期34-36,共3页
为了降低智能实时监控系统由于数据野值导致的虚警,需要在监视系统进行故障认定前对数据野值进行识别和补正。针对实际航空发动机试飞数据的情况,设计了基于最小二乘拟合结合莱特准则的自适应野值识别算法;采用适应于发动机试飞监视的... 为了降低智能实时监控系统由于数据野值导致的虚警,需要在监视系统进行故障认定前对数据野值进行识别和补正。针对实际航空发动机试飞数据的情况,设计了基于最小二乘拟合结合莱特准则的自适应野值识别算法;采用适应于发动机试飞监视的野值补正算法,达到实时监视中野值剔除的目的。通过仿真数据和实际试飞数据的验证,表明了此方法在试飞中应用的有效性。 展开更多
关键词 航空发动机 莱特准则 最小二乘 飞行试验
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GOODNESS-OF-FIT TEST WITH GENETIC BACKGROUND 被引量:1
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作者 WUJihua XIEMinyu PENGRong SUNZhihua 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2005年第1期27-34,共8页
The chi-square test is a well-known goodness-of-fit test. It is available for arbitrary alternative hypothesis, particularly for a very general alternative. However, when the alternative is a “one-sided” hypothesis,... The chi-square test is a well-known goodness-of-fit test. It is available for arbitrary alternative hypothesis, particularly for a very general alternative. However, when the alternative is a “one-sided” hypothesis, which usually appears in genetic linkage analysis, the chi-square test does not use the information offered by the one-sided hypothesis.Therefore, it is possible that an appropriate one-sided test, which uses the information,will be better than the chi-square test. This paper gives such an efficient one-sided test.Monte Carlo simulation results show that it is more powerful than the chi-square test, and its power has been increased by 30 percent as compared with that of the chi-square test in most situations. 展开更多
关键词 chi-square test goodness-of-fit test monte carlo simulation
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