One-way wave equation seismic prestack forward modeling with irregular surfaces

Mathematical geophone （MG） and equal-time stacking （ETS） principles are used to implement seismic prestack forward modeling with irregular surfaces using the oneway acoustic wave-equation. This method receives seismic primary reflections from the subsurface using a set of virtual MGs. The receivers can be located anywhere on an irregular observing surface. Moreover, the ETS method utilizes the one-way acoustic wave equation to easily and quickly image and extrapolate seismic reflection data. The method is illustrated using high single-noise ratio common shot gathers computed by numerical forward modeling of two simple models, one with a flat surface and one with an irregular surface, and a complex normal fault model. A prestack depth migration method for irregular surface topography was used to reoroduce the normal fault model with high accuracy.

A parametric bootstrap approach for one-way classification model with skew-normal random effects

In this paper,several properties of one-way classification model with skew-normal random effects are obtained,such as moment generating function,density function and noncentral skew chi-square distribution,etc.Based on the EM algorithm,we discuss the maximum likelihood(ML)estimation of unknown parameters.For testing problem of fixed effect,a parametric bootstrap(PB)approach is developed.Finally,some simulation results on the Type I error rates and powers of the PB approach are obtained,which show that the PB approach provides satisfactory performances on the Type I error rates and powers,even for small samples.For illustration,our main results are applied to a real data problem.

相依稳健t过程函数型ANOVA模型

随着数据的多元化和复杂化,函数型ANOVA模型已经被越来越多的学者研究并应用到各行各业.为了减弱模型对于离群值的敏感度,本文对于相依的多元响应变量提出了一种相依稳健t过程函数型ANOVA模型.为了刻画变量之间的相依性和保证协方差函数的正定性,本文引入了随机效应变量和卷积方法构造了一个协方差函数.另外,模型中引入了随机效应函数去描述研究对象的个体特征.统计性质,例如稳健性和信息相合性在本文中也得到了相应的研究,并通过数值模拟和实例分析来验证此模型的可行性.

Using Excel to Explore the Effects of Assumption Violations on One-Way Analysis of Variance (ANOVA) Statistical Procedures

To understand any statistical tool requires not only an understanding of the relevant computational procedures but also an awareness of the assumptions upon which the procedures are based, and the effects of violations of these assumptions. In our earlier articles (Laverty, Miket, & Kelly [1]) and (Laverty & Kelly, [2] [3]) we used Microsoft Excel to simulate both a Hidden Markov model and heteroskedastic models showing different realizations of these models and the performance of the techniques for identifying the underlying hidden states using simulated data. The advantage of using Excel is that the simulations are regenerated when the spreadsheet is recalculated allowing the user to observe the performance of the statistical technique under different realizations of the data. In this article we will show how to use Excel to generate data from a one-way ANOVA (Analysis of Variance) model and how the statistical methods behave both when the fundamental assumptions of the model hold and when these assumptions are violated. The purpose of this article is to provide tools for individuals to gain an intuitive understanding of these violations using this readily available program.

Multi-Objective Optimization of Fused Deposition Modeling for Mechanical Properties of Biopolymer Parts Using the Grey-Taguchi Method

The urgent need to develop customized functional products only possible by 3D printing had realized when faced with the unavailability of medical devices like surgical instruments during the coronavirus-19 disease and the ondemand necessity to perform surgery during space missions.Biopolymers have recently been the most appropriate option for fabricating surgical instruments via 3D printing in terms of cheaper and faster processing.Among all 3D printing techniques,fused deposition modelling(FDM)is a low-cost and more rapid printing technique.This article proposes the fabrication of surgical instruments,namely,forceps and hemostat using the fused deposition modeling(FDM)process.Excellent mechanical properties are the only indicator to judge the quality of the functional parts.The mechanical properties of FDM-processed parts depend on various process parameters.These parameters are layer height,infill pattern,top/bottom pattern,number of top/bottom layers,infill density,flow,number of shells,printing temperature,build plate temperature,printing speed,and fan speed.Tensile strength and modulus of elasticity are chosen as evaluation indexes to ascertain the mechanical properties of polylactic acid(PLA)parts printed by FDM.The experiments have performed through Taguchi’s L27orthogonal array(OA).Variance analysis(ANOVA)ascertains the significance of the process parameters and their percent contributions to the evaluation indexes.Finally,as a multiobjective optimization technique,grey relational analysis(GRA)obtains an optimal set of FDM process parameters to fabricate the best parts with comprehensive mechanical properties.Scanning electron microscopy(SEM)examines the types of defects and strong bonding between rasters.The proposed research ensures the successful fabrication of functional surgical tools with substantial ultimate tensile strength(42.6 MPa)and modulus of elasticity(3274 MPa).

激光熔覆CoCrFeNiTi高熵合金工艺优化及预测模型研究

目的探究激光熔覆工艺参数对CoCrFeNiTi高熵合金涂层质量及形貌的影响,实现激光熔覆CoCrFeNiTi高熵合金涂层形貌的精确控制。方法基于田口正交法,设计不同激光工艺参数下30CrMnSiA表面激光熔覆CoCrFeNiTi高熵合金实验,以激光功率、扫描速度、送粉速率为影响因素,以涂层稀释率、高度、宽度、裂纹密度、宽高比为响应目标,通过方差和信噪比分析影响因素与响应目标的关系,并确定最优工艺参数,建立工艺参数与CoCrFeNiTi高熵合金涂层性能和形貌的支持向量回归预测模型。结果激光功率对熔覆层稀释率、宽度和裂纹密度的影响较大,且与熔覆层稀释率、高度、宽度、裂纹密度、宽高比呈正相关。扫描速度对涂层高度、裂纹密度和宽高比的影响较大,与涂层高度呈负相关,与涂层裂纹密度和宽高比呈正相关。送粉速率对熔覆层稀释率、高度和宽高比的影响较大,与熔覆层稀释率和高度呈负相关,与熔覆层宽高比呈正相关。得到了最优工艺参数,激光功率为600 W,扫描速度为18 mm/s,送粉速率为1.6 r/min。通过预测模型测试可知,熔覆层稀释率、高度、宽度、裂纹密度和宽高比预测模型的决定系数均大于0.93。结论基于支持向量回归的CoCrFeNiTi高熵合金涂层形貌预测模型的精度较高,能够实现CoCrFeNiTi高熵合金熔覆层形貌的精确预测,为熔覆层形貌的控制提供了新的思路。

基于ANOVA模型的延边地区制造业偏离-份额分析

通过建立基于ANOVA的偏离-份额分析对延边地区制造业竞争力进行数据分析,可重新回顾进入新时期之后延边地区制造业相对于全国范围制造业的竞争力强弱,判断制造业各产业部门较国家制造业产业部门的竞争力优势水平,进而完善和改进延边地区经济发展战略。由分析结果可知,延边地区制造业总体竞争力与国内水平相比较弱,27个产业研究对象中有21个产业部门的竞争力较全国制造业对应产业部门处于竞争劣势。虽然医药制造业、纺织业等主要产业的竞争力较为突出,但是这些行业在整个延边制造业中所占的比重极小,不足以改变整个延边制造业的整体竞争力水平,导致了延边地区制造业整体增长缓慢。

Spatio-temporal variation and relationship between agricultural efficiency and irrigation intensity in a semi-arid region of India

A surging population in Karnataka State,a semi-arid region in India,poses a threat to both food security and livelihood sustainability,necessitating a concentrated effort to bolster agricultural efficiency and achieve United Naton’s Sustainable Development Goal 2(zero hunger).Therefore,in order to address the pressing issue of food scarcity in Karnataka,this study meticulously examined the spatio-temporal variation of agricultural efficiency and irrigation intensity in Karnataka,uncovering its significant dependence of agricultural efficiency on irrigation intensity.Specifically,this study used a one-way analysis of variance(ANOVA)to ascertain significant differences in the means of agricultural efficiency and irrigation intensity during 2004-2005 and 2018-2019.This study showed that the maximum improvement in agricultural efficiency index was recorded in Belgaum(40.24),Gulbarga(24.77),and Yadgir districts(22.92)between 2004-2005 and 2018-2019,which indicated the progressing trend and better scope for agriculture extension.On the contrary,some districts expressed threat(a decline of above 20.00 of agricultural efficiency index)and needed special care for the improvement of agricultural efficiency in four northern districts(Bagalkot,Bidar,Raichur,and Bijapur),three southern districts(Chitradurga,Chikballapur and Hassan),and two southern districts(Koppal and Gadag)in Karnataka.During 2004-2005,irrigation intensity varied from 3.19%to 56.39%,with the lowest irrigation intensity in Kodagu District and the highest irrigation intensity in Shimoga District.During 2018-2019,irrigation intensity changed from 0.77%to 72.77%,with the lowest irrigation intensity in Kodagu District and the highest in Dakshin Kannad District.Moreover,the research scrutinized the complex relationship between agricultural efficiency and irrigation intensity,with the correlation coefficient increased from 0.162 during 2004-2005 to 0.255 during 2018-2019.It implies that in both periods,a low positive correlation existed between these two variables.Over time,several factors(high-yield seeds and chemical fertilizers)other than irrigation intensity gradually became essential for agricultural efficiency.This research offers a wealth of valuable insights for regional planners and policy-makers contending with comparable challenges in various regions of India and other developing countries.

玻璃文物成分分析与鉴别的数学模型

针对2022年全国大学生数学建模竞赛C题“玻璃文物的成分分析与鉴别问题”中的4个问题分别进行建模分析,根据玻璃文物的化学成分含量、纹饰及颜色等数据,基于单因素方差分析,探究玻璃文物的表面风化与玻璃类型、纹饰及颜色的关系,建立ARIMA模型,预测风化前玻璃文物的化学成分含量;通过主成分分析提取玻璃文物的分类特征,结合聚类算法进行亚类划分;通过基于欧氏距离的聚类算法鉴别未知玻璃文物的类别,分析玻璃文物分类结果的敏感性;通过K-Means++聚类算法分析不同类别玻璃文物的关联关系,对不同类别玻璃文物关联关系的差异性进行判断,给出结论。

基于ANOVA方差的生态旅游者对景区管理模式的态度分析

根据环境认知差异对生态旅游者进行分类,可以探究不同类型的生态旅游者对景区管理模式的态度差异。以我国黄山、张家界、云台山以及庐山风景区为样本,对生态旅游者的态度分四组进行问卷调查,然后使用ANOVA方差分析法对不同类型的生态旅游者对景区管理模式的态度进行计量分析。研究表明,不同类型的生态旅游者对景区生态管理方式的态度确实存在明显差别:1组生态旅游者更注重旅游的生态体验,他们对当前景区管理方式在一定程度上持反对态度;2组和3组对当前景区管理方式的态度并不明显;4组为生态忧患型的生态旅游者,对于当前景区管理方式基本持肯定态度。

Meta-ANOVA方法在FTO基因rs9939609多态性位点遗传模式界定中的应用

目的：探索FTO基因rs9939609位点的遗传模式,综合评价该位点多态性与肥胖的遗传关联性。方法：全面检索国内外数据库,搜集符合纳入标准的研究资料,并按照排除标准排除。运用meta-ANOVA方法对FTO基因rs9939609位点AA、AT和TT 3种基因型携带者的体重指数（BMI）的平均水平进行比较,得到设定的参数λ判断该位点的遗传模式。结果：共纳入文献48篇,按照年龄进行分层后,少年组9篇,成年组33篇,老年组6篇。3组的AA、AT和TT 3种基因型携带者BMI平均水平差异有统计学意义[少年组（P〈0.001）,λ=0.5,β=0.656,95%CI（0.489~0.823）;成年组（P〈0.001）,λ=0.5,β=0.670,95%CI（0.562~0.778）;老年组（P〈0.001）,λ=0.5,β=0.523,95%CI（0.363~0.682）]。3组的验证遗传模式均为加性遗传。结论：FTO基因rs9939609位点多态性与肥胖有关联性,A等位基因有使BMI增加的风险,该位点的遗传模式为加性遗传。

Cp准则应用于遴选最佳ANOVA模型

以往在对特定的方差分析（ANOVA）资料指定其数学模型时，都是根据因子及因子之间的互作效应的多少来进行的，似乎在ANOVA问题当中不存在模型选择问题。本文则表明在ANOVA当中不但存在着模型选择问题，而且利用Cp准则还能导致正确的结论。

个人特质与大学生消费水平关系的研究——基于Probit模型和ANOVA模型

在512份安徽大学大学生消费的调查问卷的基础上,先用有序Probit回归模型分析个人特质对大学生消费水平的影响;再用方差分析方法分析个人特质的不同水平对于消费支出的影响;结果显示,大学生所在的年级、生源地、家庭收入状况以及大学生的理财观念对大学生消费水平影响显著,大学生的性别、专业类型和兄弟姐妹个数影响不显著,而家庭收入对于大学生的消费起到决定性影响。

Optimization of Fused Deposition Modelling (FDM) Process Parameters Using Bacterial Foraging Technique

Fused deposition modelling (FDM) is a fast growing rapid prototyping (RP) technology due to its ability to build functional parts having complex geometrical shapes in reasonable build time. The dimensional accuracy, surface roughness, mechanical strength and above all functionality of built parts are dependent on many process variables and their settings. In this study, five important process parameters such as layer thickness, orientation, raster angle, raster width and air gap have been considered to study their effects on three responses viz., tensile, flexural and impact strength of test specimen. Experiments have been conducted using central composite design (CCD) and empirical models relating each response and process parameters have been developed. The models are validated using analysis of variance (ANOVA). Finally, bacterial foraging technique is used to suggest theoretical combination of parameter settings to achieve good strength simultaneously for all responses.

Design and analysis of logarithmic spiral type sprag one-way clutch

A complete mathematical model for logarithmic spiral type sprag one-way clutch design and analysis is given.It assumes that the motion of all clutch components can be expressed by a model of epicyclic gearing.It takes advantage of Hunt-Crossley contact impact theory to calculate the contact forces between sprags and races,and it can be used for optimization of design and comparison with other types of sprag clutches.A good deal of analysis shows that the parameters of the steady windup angle,the steady contact force,the natural frequency and natural cycle of clutch have nothing to do with the initial velocity of outer race,while the parameters of the maximum transient windup angle,the maximum transient impact force and the steady engagement time increase linearly in the mode of engaging operation of clutch.It is also shown that the strut angle has great influence on the dynamic engagement performance of clutch.The parameters of the steady windup angle,the maximum transient windup angle,the steady engaging time,the steady contact force,the maximum transient impact force and the natural cycle of clutch decrease linearly nearly with the inner strut angle,while the natural frequency of the system increases linearly with the inner strut angle.

A Three-Dimensional Numerical Model for Predicting the Weld Bead Geometry Characteristics in Laser Overlap Welding of Low Carbon Galvanized Steel

Laser welding (LW) becomes one of the most economical high quality joining processes. LW offers the advantage of very controlled heat input resulting in low distortion and the ability to weld heat sensitive components. To exploit efficiently the benefits presented by LW, it is necessary to develop an integrated approach to identify and control the welding process variables in order to produce the desired weld characteristics without being forced to use the traditional and fastidious trial and error procedures. The paper presents a study of weld bead geometry characteristics prediction for laser overlap welding of low carbon galvanized steel using 3D numerical modelling and experimental validation. The temperature dependent material properties, metallurgical transformations and enthalpy method constitute the foundation of the proposed modelling approach. An adaptive 3D heat source is adopted to simulate both keyhole and conduction mode of the LW process. The simulations are performed using 3D finite element model on commercial software. The model is used to estimate the weld bead geometry characteristics for various LW parameters, such as laser power, welding speed and laser beam diameter. The calibration and validation of the 3D numerical model are based on experimental data achieved using a 3 kW Nd:Yag laser system, a structured experimental design and confirmed statistical analysis tools. The results reveal that the modelling approach can provide not only a consistent and accurate prediction of the weld characteristics under variable welding parameters and conditions but also a comprehensive and quantitative analysis of process parameters effects on the weld quality. The results show great concordance between predicted and measured values for weld bead geometry characteristics, such as depth of penetration, bead width at the top surface and bead width at the interface between sheets, with an average accuracy greater than 95%.

Numerical Investigation of Laser Surface Hardening of AISI 4340 Using 3D FEM Model for Thermal Analysis of Different Laser Scanning Patterns

Laser surface hardening is becoming one of the most successful heat treatment processes for improving wear and fatigue properties of steel parts. In this process, the heating system parameters and the material properties have important effects on the achieved hardened surface characteristics. The control of these variables using predictive modeling strategies leads to the desired surface properties without following the fastidious trial and error method. However, when the dimensions of the surface to be treated are larger than the cross section of the laser beam, various laser scanning patterns can be used. Due to their effects on the hardened surface properties, the attributes of the selected scanning patterns become significant variables in the process. This paper presents numerical and experimental investigations of four scanning patterns for laser surface hardening of AISI 4340 steel. The investigations are based on exhaustive modelling and simulation efforts carried out using a 3D finite element thermal analysis and structured experimental study according to Taguchi method. The temperature distribution and the hardness profile attributes are used to evaluate the effects of heating parameters and patterns design parameters on the hardened surface characteristics. This is very useful for integrating the scanning patterns’ features in an efficient predictive modeling approach. A structured experimental design combined to improved statistical analysis tools is used to assess the 3D model performance. The experiments are performed on a 3 kW Nd:Yag laser system. The modeling results exhibit a great agreement between the predicted and measured values for the hardened surface characteristics. The model evaluation reveals also its ability to provide not only accurate and robust predictions of the temperature distribution and the hardness profile as well an in-depth analysis of the effects of the process parameters.

家禽试验中重复测量数据的常用分析方法

在家禽试验中经常会需要对试验动物进行连续性观察而获得重复测量数据。对这类数据资料如果采用常规方差分析或者对重复测量数据的各时间点分别分析,其结果可能因为来自相同个体的多次观察数据间存在相关而加大误差,或无法充分反应数据连续观测的特性。针对动物试验中重复测量数据的统计方法,文章分析了重复测量数据的重复测量方差分析(RM-ANOVA)、多变量方差分析(MANOVA)法以及混合线性模型拟合法的适用条件,结合案例详述了如何选择合适的方法在R语言中实现对这类数据的分析,为家禽科学及相关专业涉及重复测量数据的统计分析提供参考。

Effects of Neo-Tethyan evolution on the petroleum system of Persian Gulf Superbasin

Considering the Neo-Tethyan tectonic process and the resulting environmental changes,a geodynamic model of“one-way train loading”is proposed to analyze the formation and evolution mechanism of the Persian Gulf Superbasin with the most abundant hydrocarbons in the world.The Persian Gulf Superbasin has long been in a passive continental margin setting since the Late Paleozoic in the process of unidirectional subduction,forming a superior regional space of hydrocarbon accu-mulation.During the Jurassic-Cretaceous,the Persian Gulf Superbasin drifted slowly at low latitudes,and developed multiple superimposed source-reservoir-caprock assemblages as a combined result of several global geological events such as the Hadley Cell,the Equatorial Upwelling Current,and the Jurassic True Polar Wander.The collision during the evolution of the foreland basin since the Cenozoic led to weak destruction,which was conducive to the preservation of oil and gas.Accordingly,it is be-lieved that the slow drifting and long retention in favorable climate zone of the continent are the critical factors for hydrocarbon enrichment.Moreover,the prospects of hydrocarbon potential in other continents in the Neo-Tethyan were proposed.

吉林省乡村教师职业认同与留职意愿的关系研究

以吉林省452份乡村教师调研数据为研究对象,分析吉林省乡村教师留职意愿的特征,发现吉林省乡村教师中超过一半希望能够继续留职从事乡村教师工作.教师基本信息和职业认同对乡村教师留职意愿影响的单因素方差分析结果表明:不同性别、年龄、婚姻状况、学历的乡村教师留职意愿有显著性差异;而不同职称、教龄、学校类型和学校位置的乡村教师留职意愿无显著性差异;不同职业价值观、角色价值观、职业行为倾向、职业归属感及职业认同的乡村教师留职意愿有显著性差异.乡村教师留职意愿影响因素模型的多元线性回归分析结果表明,职业认同、性别、年龄、婚姻状况、学历对乡村教师留职意愿有显著影响,其中职业认同和年龄是正向影响,性别和学历是负向影响.而职称、教龄、学校类型、学校位置对乡村教师留职意愿没有显著性影响.多元线性回归模型结果与单因素方差分析模型结果高度一致.进而提出预提升乡村教师留职意愿应高度重视提升乡村青年教师的职业认同感,并提出具体建议.