首页 > 最新文献

Applied and Computational Mathematics最新文献

英文 中文
Two-scale Finite Element Discretizations for Semilinear Parabolic Equations 半线性抛物型方程的双尺度有限元离散
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-11-16 DOI: 10.11648/J.ACM.20200906.12
F. Liu
In this paper, to reduce the computational cost of solving semilinear parabolic equations on a tensor product domain Ω⊂ℝd with d = 2 or 3, some two-scale finite element discretizations are proposed and analyzed. The time derivative in semilinear parabolic equations is approximated by the backward Euler finite difference scheme. The two-scale finite element method is designed for the space discretization. The idea of the two-scale finite element method is based on an understanding of a finite element solution to an elliptic problem on a tensor product domain. The high frequency parts of the finite element solution can be well captured on some univariate fine grids and the low frequency parts can be approximated on a coarse grid. Thus the two-scale finite element approximation is defined as a linear combination of some standard finite element approximations on some univariate fine grids and a coarse grid satisfying H = O (h1/2), where h and H are the fine and coarse mesh widths, respectively. It is shown theoretically and numerically that the backward Euler two-scale finite element solution not only achieves the same order of accuracy in the H1 (Ω) norm as the backward Euler standard finite element solution, but also reduces the number of degrees of freedom from O(h-d×τ-1) to O(h-((d)+1)/2×τ-1) where τ is the time step. Consequently the backward Euler two-scale finite element method for semilinear parabolic equations is more efficient than the backward Euler standard finite element method.
本文为了减少在d = 2或3的张量积域Ω上求解半线性抛物方程的计算代价,提出并分析了几种双尺度有限元离散化方法。用后向欧拉有限差分格式逼近半线性抛物方程的时间导数。设计了双尺度有限元法进行空间离散化。双尺度有限元方法的思想是基于对张量积域上椭圆问题的有限元解的理解。有限元解的高频部分可以在一些单变量细网格上很好地捕获,低频部分可以在粗网格上近似。因此,双尺度有限元近似定义为在满足H = O (h1/2)的单变量细网格和粗网格上的一些标准有限元近似的线性组合,其中H和H分别为细网格宽度和粗网格宽度。理论和数值表明,向后欧拉双尺度有限元解不仅在H1 (Ω)范数上达到与向后欧拉标准有限元解相同的精度阶数,而且将自由度从O(h-d×τ-1)减少到O(h-(d)+1)/2×τ-1),其中τ为时间步长。因此,用后向欧拉双尺度有限元法求解半线性抛物方程比用后向欧拉标准有限元法求解更有效。
{"title":"Two-scale Finite Element Discretizations for Semilinear Parabolic Equations","authors":"F. Liu","doi":"10.11648/J.ACM.20200906.12","DOIUrl":"https://doi.org/10.11648/J.ACM.20200906.12","url":null,"abstract":"In this paper, to reduce the computational cost of solving semilinear parabolic equations on a tensor product domain Ω⊂ℝd with d = 2 or 3, some two-scale finite element discretizations are proposed and analyzed. The time derivative in semilinear parabolic equations is approximated by the backward Euler finite difference scheme. The two-scale finite element method is designed for the space discretization. The idea of the two-scale finite element method is based on an understanding of a finite element solution to an elliptic problem on a tensor product domain. The high frequency parts of the finite element solution can be well captured on some univariate fine grids and the low frequency parts can be approximated on a coarse grid. Thus the two-scale finite element approximation is defined as a linear combination of some standard finite element approximations on some univariate fine grids and a coarse grid satisfying H = O (h1/2), where h and H are the fine and coarse mesh widths, respectively. It is shown theoretically and numerically that the backward Euler two-scale finite element solution not only achieves the same order of accuracy in the H1 (Ω) norm as the backward Euler standard finite element solution, but also reduces the number of degrees of freedom from O(h-d×τ-1) to O(h-((d)+1)/2×τ-1) where τ is the time step. Consequently the backward Euler two-scale finite element method for semilinear parabolic equations is more efficient than the backward Euler standard finite element method.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87224439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
A Construction of Imprimitive Groups of Rank 4 or 5 4阶或5阶非原始群的构造
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-11-04 DOI: 10.11648/J.ACM.20200906.11
Chang Wang, Renbing Xiao
Let G be a transitive permutation group acting on a finite set Ω. For a point α of Ω, the set of the images of G acting on α is called the orbit of α under G and is denoted by αG, and the set of elements in G which fix α is called the stabilizer of α in G and is denoted by Gα. We can get some new orbits by using the natural action of the stabilizer Gα on Ω, and then we can define the suborbit of G. The suborbits of G on Ω are defined as the orbits of a point stabilizer on Ω. The number of suborbits is called the rank of G and the length of suborbits is called the subdegree of G. For finite primitive groups, the study of the rank and subdegrees of group has a long history. In this paper, we construct a class of imprimitive permutation groups of rank 4 or 5 by using imprimitive action and product action of wreath product, determine the number and the length of the suborbits, and extend the results to imprimitive permutation groups of rank m+1 and 2n+1, where m and n are positive integers.
设G是作用于有限集合Ω上的传递置换群。对于Ω点α, G作用于α的像的集合称为α在G下的轨道,记为αG, G中固定α的元素的集合称为α在G中的稳定子,记为Gα。利用稳定剂Gα在Ω上的自然作用,我们可以得到一些新的轨道,然后我们可以定义G的子轨道。将G在Ω上的子轨道定义为Ω上的点稳定剂的轨道。子轨道的个数称为G的秩,子轨道的长度称为G的子度。对于有限原始群,对群的秩和子度的研究已有很长的历史。本文利用环积的非原作用和乘积作用构造了一类秩为4或5的非原置换群,确定了子轨道的个数和长度,并将结果推广到秩为m+1和2n+1的非原置换群,其中m和n为正整数。
{"title":"A Construction of Imprimitive Groups of Rank 4 or 5","authors":"Chang Wang, Renbing Xiao","doi":"10.11648/J.ACM.20200906.11","DOIUrl":"https://doi.org/10.11648/J.ACM.20200906.11","url":null,"abstract":"Let G be a transitive permutation group acting on a finite set Ω. For a point α of Ω, the set of the images of G acting on α is called the orbit of α under G and is denoted by αG, and the set of elements in G which fix α is called the stabilizer of α in G and is denoted by Gα. We can get some new orbits by using the natural action of the stabilizer Gα on Ω, and then we can define the suborbit of G. The suborbits of G on Ω are defined as the orbits of a point stabilizer on Ω. The number of suborbits is called the rank of G and the length of suborbits is called the subdegree of G. For finite primitive groups, the study of the rank and subdegrees of group has a long history. In this paper, we construct a class of imprimitive permutation groups of rank 4 or 5 by using imprimitive action and product action of wreath product, determine the number and the length of the suborbits, and extend the results to imprimitive permutation groups of rank m+1 and 2n+1, where m and n are positive integers.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88787595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Age-Infection Model and Control of Marek Disease 马立克病的年龄感染模型及控制
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-10-13 DOI: 10.11648/j.acm.20200905.13
Uwakwe Joy Ijeoma, Inyama Simeon Chioma, O. Andrew
We formulated three compartmental model of Marek Disease model. We first determined the basic Reproduction number and the existence of Steady (Equilibrium) states (disease-free and endemic). Conditions for the local stability of the disease-free and endemic steady states were determined. Further, the Global stability of the disease-free equilibrium (DFE) and endemic equilibrium were proved using Lyponav method. We went further to carry out the sensitivity analysis or parametric dependence on R0 and later formulated the optimal control problem. We finally looked at numerical Results on poultry productivity in the presence of Marek disease and we drew five graphs to demonstrate this. The first figure shows the effect of both vaccination (v) and biosecurity measures (u) on the latently infected birds. The population of infected birds increases speedily and then remains stable without the application of any control measure, with the controls, the population increases to about 145 and then begins to reduce from day 8 till it drops to 50 on day 20 and then remains stable. With this strategy, only bird vaccination (v) is applied to control the system while the other control is set to zero. In the second figure, the effect of bird vaccination and its’ positive impact is revealed, though there is an increase to about 160 before a decrease occurs. From the third figure, as the control (u) ranges from 0.2 to 0.9, we see that the bird population still has a high level of latently infected birds. This result from figure shows that the bird population is not free from the disease, hence, the biosecurity control strategy is not effective without vaccination of susceptible birds and hence it is not preferable as the only control measure for marek disease. The numerical result in the fourth figure shows that as the latently infected bird population increases without control, with vaccination it decreases as more susceptible birds are vaccinated. From the fifth figure we observe, that as the control parameter increases, the total deaths by infection reduces, also as the age of the infection increases to the maximum age of infection which is 6 months (thatis, T=24 weeks), the number of deaths increases to 30 in a day. Hence, control measures should be applied at the early ages of infection in order to avoid high mortality rate during the outbreak of the disease.
我们建立了马立克病模型的三室模型。我们首先确定了基本繁殖数和稳定(平衡)状态(无病和地方病)的存在。确定了无病和地方性稳定状态的局部稳定条件。此外,利用Lyponav方法证明了无病平衡(DFE)和地方性平衡的全局稳定性。我们进一步进行了灵敏度分析或参数对R0的依赖,并在此基础上制定了最优控制问题。我们最后看了马立克病下家禽生产力的数值结果,我们画了五张图来证明这一点。第一个数字显示了疫苗接种(v)和生物安全措施(u)对潜伏感染禽类的影响。在不采取任何控制措施的情况下,感染禽的数量迅速增加,然后保持稳定,有了控制,从第8天开始增加到145只左右,然后开始减少,到第20天下降到50只,然后保持稳定。采用该策略,只应用禽类疫苗接种(v)来控制系统,而将其他控制设置为零。在第二张图中,显示了禽类疫苗接种的效果及其积极影响,尽管在下降之前增加到160左右。从第三个图中,当控制(u)在0.2到0.9之间时,我们看到鸟类种群中潜伏感染的鸟类仍然很高。从图中可以看出,鸟类种群并没有完全摆脱疾病,因此,如果没有对易感鸟类进行疫苗接种,生物安全控制策略是无效的,因此不适合作为唯一的控制措施。图4中的数值结果表明,由于潜伏感染的鸟类数量在不受控制的情况下增加,接种疫苗后,随着更多易感鸟类接种疫苗,潜伏感染的鸟类数量减少。从图5中我们观察到,随着控制参数的增加,感染造成的总死亡人数减少,随着感染年龄增加到感染的最大年龄,即6个月(即T=24周),死亡人数增加到每天30人。因此,应在感染的早期采取控制措施,以避免疾病爆发期间的高死亡率。
{"title":"Age-Infection Model and Control of Marek Disease","authors":"Uwakwe Joy Ijeoma, Inyama Simeon Chioma, O. Andrew","doi":"10.11648/j.acm.20200905.13","DOIUrl":"https://doi.org/10.11648/j.acm.20200905.13","url":null,"abstract":"We formulated three compartmental model of Marek Disease model. We first determined the basic Reproduction number and the existence of Steady (Equilibrium) states (disease-free and endemic). Conditions for the local stability of the disease-free and endemic steady states were determined. Further, the Global stability of the disease-free equilibrium (DFE) and endemic equilibrium were proved using Lyponav method. We went further to carry out the sensitivity analysis or parametric dependence on R0 and later formulated the optimal control problem. We finally looked at numerical Results on poultry productivity in the presence of Marek disease and we drew five graphs to demonstrate this. The first figure shows the effect of both vaccination (v) and biosecurity measures (u) on the latently infected birds. The population of infected birds increases speedily and then remains stable without the application of any control measure, with the controls, the population increases to about 145 and then begins to reduce from day 8 till it drops to 50 on day 20 and then remains stable. With this strategy, only bird vaccination (v) is applied to control the system while the other control is set to zero. In the second figure, the effect of bird vaccination and its’ positive impact is revealed, though there is an increase to about 160 before a decrease occurs. From the third figure, as the control (u) ranges from 0.2 to 0.9, we see that the bird population still has a high level of latently infected birds. This result from figure shows that the bird population is not free from the disease, hence, the biosecurity control strategy is not effective without vaccination of susceptible birds and hence it is not preferable as the only control measure for marek disease. The numerical result in the fourth figure shows that as the latently infected bird population increases without control, with vaccination it decreases as more susceptible birds are vaccinated. From the fifth figure we observe, that as the control parameter increases, the total deaths by infection reduces, also as the age of the infection increases to the maximum age of infection which is 6 months (thatis, T=24 weeks), the number of deaths increases to 30 in a day. Hence, control measures should be applied at the early ages of infection in order to avoid high mortality rate during the outbreak of the disease.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88301795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Exploiting Machine Learning Algorithms for Predicting Crash Injury Severity in Yemen: Hospital Case Study 利用机器学习算法预测也门碰撞伤害严重程度:医院案例研究
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-09-29 DOI: 10.11648/J.ACM.20200905.12
Tariq Al-Moqri, Xiao Haijun, J. P. Namahoro, E. Alfalahi, Ibrahim Alwesabi
This study focused on exploiting machine learning algorithms for classifying and predicting injury severity of vehicle crashes in Yemen. The primary objective is to assess the contribution of the leading causes of injury severity. The selected machine learning algorithms compared with traditional statistical methods. The filtrated second data collected within two months (August-October 2015) from the two main hospitals included 156 injured patients of vehicle crashes reported from 128 locations. The data classified into three categories of injury severity: Severe, Serious, and Minor. It balanced using a synthetic minority oversampling technique (SMOTE). Multinomial logit model (MNL) compared with five machine learning classifiers: Naive Bayes (NB), J48 Decision Tree, Random Forest (RF), Support Vector Machine (SVM), and Multilayer Perceptron (MLP). The results showed that most of machine learning-based algorithms performed well in predicting and classifying the severity of the traffic injury. Out of five classifiers, RF is the best classifier with 94.84% of accuracy. The characteristics of road type, total injured person, crash type, road user, transport way to the emergency department (ED), and accident action were the most critical factors in the severity of the traffic injury. Enhancing strategies for using roadway facilities may improve the safety of road users and regulations.
本研究的重点是利用机器学习算法对也门车辆碰撞的伤害严重程度进行分类和预测。主要目的是评估损伤严重程度的主要原因的贡献。所选择的机器学习算法与传统的统计方法进行了比较。在两个月内(2015年8月至10月)从两家主要医院收集的过滤后的第二次数据包括来自128个地点报告的156名车祸伤者。数据分为三种损伤严重程度:严重、严重和轻微。它使用合成少数过采样技术(SMOTE)进行平衡。多项logit模型(MNL)与五种机器学习分类器:朴素贝叶斯(NB)、J48决策树、随机森林(RF)、支持向量机(SVM)和多层感知器(MLP)进行了比较。结果表明,大多数基于机器学习的算法在预测和分类交通伤害严重程度方面表现良好。在5个分类器中,RF是最好的分类器,准确率为94.84%。道路类型特征、受伤总人数特征、碰撞类型特征、道路使用者特征、前往急诊科的运输方式特征和事故行为特征是影响交通伤害严重程度的最关键因素。加强道路设施的使用策略可以提高道路使用者的安全性和法规。
{"title":"Exploiting Machine Learning Algorithms for Predicting Crash Injury Severity in Yemen: Hospital Case Study","authors":"Tariq Al-Moqri, Xiao Haijun, J. P. Namahoro, E. Alfalahi, Ibrahim Alwesabi","doi":"10.11648/J.ACM.20200905.12","DOIUrl":"https://doi.org/10.11648/J.ACM.20200905.12","url":null,"abstract":"This study focused on exploiting machine learning algorithms for classifying and predicting injury severity of vehicle crashes in Yemen. The primary objective is to assess the contribution of the leading causes of injury severity. The selected machine learning algorithms compared with traditional statistical methods. The filtrated second data collected within two months (August-October 2015) from the two main hospitals included 156 injured patients of vehicle crashes reported from 128 locations. The data classified into three categories of injury severity: Severe, Serious, and Minor. It balanced using a synthetic minority oversampling technique (SMOTE). Multinomial logit model (MNL) compared with five machine learning classifiers: Naive Bayes (NB), J48 Decision Tree, Random Forest (RF), Support Vector Machine (SVM), and Multilayer Perceptron (MLP). The results showed that most of machine learning-based algorithms performed well in predicting and classifying the severity of the traffic injury. Out of five classifiers, RF is the best classifier with 94.84% of accuracy. The characteristics of road type, total injured person, crash type, road user, transport way to the emergency department (ED), and accident action were the most critical factors in the severity of the traffic injury. Enhancing strategies for using roadway facilities may improve the safety of road users and regulations.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73886231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
A log-Dagum Weibull Distribution: Properties and Characterization 对数-达格姆威布尔分布:性质和表征
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-09-18 DOI: 10.20944/PREPRINTS202009.0428.V1
A. Khadim, A. Saghir, Tassaddaq Hussain
Developments of new probability models for data analysis are keen interest of importance for all fields. The log-Dagum distribution has a prominent role in the theory and practice of statistics. In this article, a new family of continuous distributions generated from a log Dagum random variable called the log-Dagum Weibull distribution is proposed. The key properties of the proposed distribution are derived. Its density function can be symmetrical, left-skewed, right-skewed and reversed-J shaped and can have increasing, decreasing, bathtub hazard rates shaped. The model parameters are estimated by the method of maximum likelihood and illustrate its importance by means of applications to real data sets.
发展用于数据分析的新的概率模型是各个领域的重要兴趣。对数-达格姆分布在统计学理论和实践中具有重要的作用。本文提出了一种由对数Dagum随机变量生成的连续分布,称为对数-Dagum威布尔分布。推导了该分布的关键性质。其密度函数可以是对称的、左偏的、右偏的和倒j型的,可以是增加的、减少的、浴缸危险率的形状。用极大似然法对模型参数进行了估计,并通过对实际数据集的应用说明了极大似然法的重要性。
{"title":"A log-Dagum Weibull Distribution: Properties and Characterization","authors":"A. Khadim, A. Saghir, Tassaddaq Hussain","doi":"10.20944/PREPRINTS202009.0428.V1","DOIUrl":"https://doi.org/10.20944/PREPRINTS202009.0428.V1","url":null,"abstract":"Developments of new probability models for data analysis are keen interest of importance for all fields. The log-Dagum distribution has a prominent role in the theory and practice of statistics. In this article, a new family of continuous distributions generated from a log Dagum random variable called the log-Dagum Weibull distribution is proposed. The key properties of the proposed distribution are derived. Its density function can be symmetrical, left-skewed, right-skewed and reversed-J shaped and can have increasing, decreasing, bathtub hazard rates shaped. The model parameters are estimated by the method of maximum likelihood and illustrate its importance by means of applications to real data sets.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86368173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Intuitionistic Fuzzy Set and Its Application in Corona Covid-19 直觉模糊集及其在冠状病毒感染中的应用
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-09-03 DOI: 10.11648/J.ACM.20200905.11
A. M. Kozae, M. Shokry, M. Omran
Intuitionistic Fuzzy set (IFS) theory plays an important role in real life and engineering problems. There are many model involving fuzzy matrices to deal with different complicated aspects. Intuitionistic fuzzy set (IFS) is useful in providing a flexible model for developing the uncertainty and vagueness involved in making decisions where the theories of uncertainty are very useful to treat with mathematics that needs to address. In other words, the application of intuitionistic fuzzy sets instead of fuzzy sets means the introduction of another degree of freedom into a set description. Intuitionistic fuzzy set (IFS) called the generalization of fuzzy sets was proposed in K. T. Atanassov. So, we can use it in decision making. We examined the definition of IFS and puts new definitions of IFS (Intuitionistic fuzzy set) in this paper and suggested its implementation in the Corona Covid-19. For several similar real-life cases the suggested approach can be applied.
直觉模糊集(IFS)理论在现实生活和工程问题中起着重要作用。有许多涉及模糊矩阵的模型来处理各种复杂的问题。直觉模糊集(IFS)可以提供一个灵活的模型,用于开发决策中涉及的不确定性和模糊性,其中不确定性理论对于处理需要解决的数学问题非常有用。换句话说,用直觉模糊集代替模糊集意味着在集合描述中引入另一个自由度。直觉模糊集(IFS)是由K. T. Atanassov提出的,称为模糊集的泛化。所以,我们可以用它来做决策。本文对IFS的定义进行了研究,提出了IFS(直觉模糊集)的新定义,并提出了IFS在新冠肺炎疫情中的实施建议。对于几个类似的现实案例,建议的方法可以应用。
{"title":"Intuitionistic Fuzzy Set and Its Application in Corona Covid-19","authors":"A. M. Kozae, M. Shokry, M. Omran","doi":"10.11648/J.ACM.20200905.11","DOIUrl":"https://doi.org/10.11648/J.ACM.20200905.11","url":null,"abstract":"Intuitionistic Fuzzy set (IFS) theory plays an important role in real life and engineering problems. There are many model involving fuzzy matrices to deal with different complicated aspects. Intuitionistic fuzzy set (IFS) is useful in providing a flexible model for developing the uncertainty and vagueness involved in making decisions where the theories of uncertainty are very useful to treat with mathematics that needs to address. In other words, the application of intuitionistic fuzzy sets instead of fuzzy sets means the introduction of another degree of freedom into a set description. Intuitionistic fuzzy set (IFS) called the generalization of fuzzy sets was proposed in K. T. Atanassov. So, we can use it in decision making. We examined the definition of IFS and puts new definitions of IFS (Intuitionistic fuzzy set) in this paper and suggested its implementation in the Corona Covid-19. For several similar real-life cases the suggested approach can be applied.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90988987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 11
Explore the Characteristics of Age, BMI and Blood Composition of Breast Cancer Patients Based on Multivariate Statistical Analysis 基于多元统计分析探讨乳腺癌患者年龄、BMI及血液成分的特征
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-08-22 DOI: 10.11648/j.acm.20200904.15
R. Dong
In this paper, through a series of analysis and testing of breast cancer detection data, the statistical rules of multiple objects and multiple indicators are analyzed in the case of their correlation. First of all, univariate diagnosis and multivariate diagnosis were performed on the data. Among them, when studying the correlation between variables, it was found that HOMA had a clear linear positive correlation with insulin content in blood. It is worth noting that some patients with breast cancer show a high degree of insulin resistance and blood insulin content, which is a feature not found in samples without breast cancer. Then, through single factor analysis of variance, we believe that there were significant differences in blood test conditions, ages, and BMI indicators of samples of different health conditions. Next, the principal component analysis was used to reduce the dimension of the data. In this study, the differences in age, BMI, and blood component content between the two groups with different health conditions can be summarized by these two independent factors. Among them, the absolute value of the MCP-1 (monocyte chemoattractant protein 1) coefficient in the main component 1 is large, reflecting the characteristics of the blood component of the sample; the load values of glucose and leptin in the main component 2 are large, reflecting similar results. Then, assuming the use of m = 3 factor model and the use of maximum likelihood method and principal component method, the original data and factor rotation data are re-analyzed, so that the variables are reduced to 3 factors for analysis. Among them, the maximum likelihood method is used to estimate the factor rotation data. The first factor reflects the insulin resistance factor attributed to insulin and HOMA indicators, and the second factor reflects the body fat and thin factor attributed to BMI and leptin. The third factor reflects the glucose content in the blood. Finally, by setting different misjudgment costs for discriminant analysis, the obtained APER is 0.1638 and EAER is 0.1872. Among them, the probability of discriminating patients with breast cancer from not having breast cancer is 0.09375, which is a low rate of misjudgment and also means the model established in this paper is efficient.
本文通过对乳腺癌检测数据的一系列分析和检验,分析了多对象、多指标在相关性情况下的统计规律。首先对数据进行单因素诊断和多因素诊断。其中,在研究变量间的相关性时,发现HOMA与血液中胰岛素含量有明显的线性正相关。值得注意的是,一些乳腺癌患者表现出高度的胰岛素抵抗和血液胰岛素含量,这是在没有乳腺癌的样本中没有发现的特征。然后,通过单因素方差分析,我们认为不同健康状况样本的血液检查条件、年龄、BMI指标存在显著差异。其次,采用主成分分析法对数据进行降维。在本研究中,不同健康状况的两组在年龄、BMI和血液成分含量上的差异可以通过这两个独立的因素来总结。其中,主成分1中的MCP-1(单核细胞趋化蛋白1)系数绝对值较大,反映了样品血液成分的特点;主成分2中葡萄糖和瘦素的负荷值较大,反映出相似的结果。然后,假设使用m = 3因子模型,使用极大似然法和主成分法,对原始数据和因子旋转数据进行重新分析,使变量减少到3个因子进行分析。其中,最大似然法用于估计因子旋转数据。第一个因素反映了胰岛素和HOMA指标导致的胰岛素抵抗因素,第二个因素反映了BMI和leptin导致的体脂和体瘦因素。第三个因素反映了血液中的葡萄糖含量。最后,通过设置不同的误判代价进行判别分析,得到的APER为0.1638,EAER为0.1872。其中,判别乳腺癌患者与非乳腺癌患者的概率为0.09375,误判率较低,也说明本文建立的模型是有效的。
{"title":"Explore the Characteristics of Age, BMI and Blood Composition of Breast Cancer Patients Based on Multivariate Statistical Analysis","authors":"R. Dong","doi":"10.11648/j.acm.20200904.15","DOIUrl":"https://doi.org/10.11648/j.acm.20200904.15","url":null,"abstract":"In this paper, through a series of analysis and testing of breast cancer detection data, the statistical rules of multiple objects and multiple indicators are analyzed in the case of their correlation. First of all, univariate diagnosis and multivariate diagnosis were performed on the data. Among them, when studying the correlation between variables, it was found that HOMA had a clear linear positive correlation with insulin content in blood. It is worth noting that some patients with breast cancer show a high degree of insulin resistance and blood insulin content, which is a feature not found in samples without breast cancer. Then, through single factor analysis of variance, we believe that there were significant differences in blood test conditions, ages, and BMI indicators of samples of different health conditions. Next, the principal component analysis was used to reduce the dimension of the data. In this study, the differences in age, BMI, and blood component content between the two groups with different health conditions can be summarized by these two independent factors. Among them, the absolute value of the MCP-1 (monocyte chemoattractant protein 1) coefficient in the main component 1 is large, reflecting the characteristics of the blood component of the sample; the load values of glucose and leptin in the main component 2 are large, reflecting similar results. Then, assuming the use of m = 3 factor model and the use of maximum likelihood method and principal component method, the original data and factor rotation data are re-analyzed, so that the variables are reduced to 3 factors for analysis. Among them, the maximum likelihood method is used to estimate the factor rotation data. The first factor reflects the insulin resistance factor attributed to insulin and HOMA indicators, and the second factor reflects the body fat and thin factor attributed to BMI and leptin. The third factor reflects the glucose content in the blood. Finally, by setting different misjudgment costs for discriminant analysis, the obtained APER is 0.1638 and EAER is 0.1872. Among them, the probability of discriminating patients with breast cancer from not having breast cancer is 0.09375, which is a low rate of misjudgment and also means the model established in this paper is efficient.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87915752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Improved Preservation Technology for Non-Instantaneous Deteriorating Inventory Using Boundary Condition Estimation 基于边界条件估计的非瞬时变质库存改进保存技术
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-07-17 DOI: 10.11648/j.acm.20200904.12
Ihsan Hishamuddin, S. S. Supadi, M. Omar
Various forms of preservation technology nowadays allow businesses to handle valuable perishable items with greater flexibility. Even with a wide variety of preservation techniques, the mathematical modelling of its implementation in EOQ literature remains rigid. The paper aims to integrate an improved preservation technology in a non-instantaneous deteriorating inventory model for businesses maximizing their average total cycle profit. The improved preservation technology furthers the delay to the time within the cycle where deterioration begins and enhances the durability of inventory that allows operators to employ a less prudent holding facility. Another improvement in this area is the accurate accumulation of preservation cost depending on the inventory level at hand. The conventional EOQ method of forming the objective function before choosing the optimal values for our two decision variables (Cycle time and level of preservation) is undertaken. The cycle time is split in two, differing in their inventory process (deterioration beginning in the second period). The time when deterioration begins is derived using the model's boundary conditions, a first attempt within the area. The optimal solution set is solved for a numerical example using an algorithm to demonstrate the model and prove the global nature of the solution. An investigation into the gains from the improved preservation technology is conducted by dissecting the effects within each individual component within the objective function. 3 separate channels by which this improved preservation technology modelling benefits the business model is found namely shifting to the higher profitable period, effects towards preservation affected costs and the returns to scale from successively increasing preservation levels. Sensitivity analysis is conducted to demonstrate and confirm the findings. The paper discovers great benefits from such an improved modelling that warrants further attention within the scope of preserved inventory models, especially on how levels of preservation could influence the traditional decision variable optimized such as cycle time or ordering frequency. Findings of the paper would have significant benefits to different inventory models with its own delay before deterioration and holding facility requirement.
如今,各种形式的保存技术使企业能够更灵活地处理有价值的易腐物品。即使有各种各样的保存技术,EOQ文献中对其实现的数学建模仍然是僵化的。本文旨在将改进的保存技术集成到非瞬时变质库存模型中,使企业的平均总周期利润最大化。改进的保存技术进一步延迟了周期内开始变质的时间,并提高了库存的耐久性,从而使作业者能够采用不那么谨慎的保存设施。这方面的另一个改进是根据手头的库存水平准确地积累保存成本。采用传统的EOQ方法,先形成目标函数,然后选择两个决策变量(周期时间和保存水平)的最优值。周期时间分为两个,不同的库存过程(恶化开始于第二个周期)。使用模型的边界条件,即区域内的第一次尝试,推导出退化开始的时间。最后用一种算法求解了一个数值算例的最优解集,以证明该模型和解的全局性。通过分析目标函数内每个单独成分的影响,对改进的保存技术的收益进行了调查。这一改进的保存技术模型通过3个不同的渠道使商业模式受益,即转向更高的盈利期,对保存的影响影响了成本,以及从不断提高的保存水平中获得的规模回报。进行敏感性分析以证明和确认研究结果。本文发现这种改进的模型有很大的好处,值得在保存库存模型的范围内进一步关注,特别是保存水平如何影响优化的传统决策变量,如周期时间或订购频率。本文的研究结果对不同的库存模型具有显著的借鉴意义。
{"title":"Improved Preservation Technology for Non-Instantaneous Deteriorating Inventory Using Boundary Condition Estimation","authors":"Ihsan Hishamuddin, S. S. Supadi, M. Omar","doi":"10.11648/j.acm.20200904.12","DOIUrl":"https://doi.org/10.11648/j.acm.20200904.12","url":null,"abstract":"Various forms of preservation technology nowadays allow businesses to handle valuable perishable items with greater flexibility. Even with a wide variety of preservation techniques, the mathematical modelling of its implementation in EOQ literature remains rigid. The paper aims to integrate an improved preservation technology in a non-instantaneous deteriorating inventory model for businesses maximizing their average total cycle profit. The improved preservation technology furthers the delay to the time within the cycle where deterioration begins and enhances the durability of inventory that allows operators to employ a less prudent holding facility. Another improvement in this area is the accurate accumulation of preservation cost depending on the inventory level at hand. The conventional EOQ method of forming the objective function before choosing the optimal values for our two decision variables (Cycle time and level of preservation) is undertaken. The cycle time is split in two, differing in their inventory process (deterioration beginning in the second period). The time when deterioration begins is derived using the model's boundary conditions, a first attempt within the area. The optimal solution set is solved for a numerical example using an algorithm to demonstrate the model and prove the global nature of the solution. An investigation into the gains from the improved preservation technology is conducted by dissecting the effects within each individual component within the objective function. 3 separate channels by which this improved preservation technology modelling benefits the business model is found namely shifting to the higher profitable period, effects towards preservation affected costs and the returns to scale from successively increasing preservation levels. Sensitivity analysis is conducted to demonstrate and confirm the findings. The paper discovers great benefits from such an improved modelling that warrants further attention within the scope of preserved inventory models, especially on how levels of preservation could influence the traditional decision variable optimized such as cycle time or ordering frequency. Findings of the paper would have significant benefits to different inventory models with its own delay before deterioration and holding facility requirement.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88859566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 2
Some Metric Properties of Semi-Regular Equilateral Nonagons 半正等边nonagon的一些度量性质
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-06-18 DOI: 10.11648/J.ACM.20200903.17
Nenad Stojanović
A simple polygon that either has equal all sides or all interior angles is called a semi-regular nonagon. In terms of this definition, we can distinguish between two types of semi-regular polygons: equilateral polygons (that have equal all sides and different interior angles) and equiangular polygons (that have equal interior angles and different sides). Unlike regular polygons, one characteristic element is not enough to analyze the metric properties of semi-regular polygons, and an additional one is needed. To select this additional characteristic element, note that the following regular triangles can be inscribed to a semi-regular equilateral nonagon by joining vertices: ∆A1 A4A7, △ A2 A5 A8, △A3 A6 A9. Now have a look at triangle △A1 A4A7. Let us use the mark φ=∡(a,b1) to mark the angle between side a of the semi-regular nonagon and side b1 of the inscribed regular triangle. In interpreting the metric properties of a semi-regular equilateral nonagon, in addition to its side, we also use the angle that such side creates with the side of one of the three regular triangles that can be inscribed to such semi-regular nonagon. We consider the way in which convexity, possibility of construction, surface area, and other properties depend on a side of the semi-regular nonagon and angle φ=∡(a,b1).
所有边相等或所有内角相等的简单多边形称为半正多边形。根据这个定义,我们可以区分两种类型的半正多边形:等边多边形(所有边相等,内角不同)和等角多边形(内角相等,边不同)。与正多边形不同的是,半正多边形的度量特性分析只需要一个特征元素是不够的,还需要增加一个特征元素。要选择这个额外的特征元素,请注意以下正三角形可以通过连接顶点来切边到半正等边nonagon:∆A1 A4A7,△A2 A5 A8,△A3 A6 A9。现在看三角形△A1 A4A7。我们用标记φ=∡(a,b1)来标记半正三角形的a边与内切正三角形的b1边之间的夹角。在解释半正等边三角形的度量特性时,除了它的边,我们还使用这个边与三个正三角形中的一个的边形成的角,这三个正三角形可以被切成这个半正等边三角形。我们考虑凸性、构造可能性、表面积和其他性质依赖于半正nonagon的边和角φ=∡(a,b1)的方式。
{"title":"Some Metric Properties of Semi-Regular Equilateral Nonagons","authors":"Nenad Stojanović","doi":"10.11648/J.ACM.20200903.17","DOIUrl":"https://doi.org/10.11648/J.ACM.20200903.17","url":null,"abstract":"A simple polygon that either has equal all sides or all interior angles is called a semi-regular nonagon. In terms of this definition, we can distinguish between two types of semi-regular polygons: equilateral polygons (that have equal all sides and different interior angles) and equiangular polygons (that have equal interior angles and different sides). Unlike regular polygons, one characteristic element is not enough to analyze the metric properties of semi-regular polygons, and an additional one is needed. To select this additional characteristic element, note that the following regular triangles can be inscribed to a semi-regular equilateral nonagon by joining vertices: ∆A1 A4A7, △ A2 A5 A8, △A3 A6 A9. Now have a look at triangle △A1 A4A7. Let us use the mark φ=∡(a,b1) to mark the angle between side a of the semi-regular nonagon and side b1 of the inscribed regular triangle. In interpreting the metric properties of a semi-regular equilateral nonagon, in addition to its side, we also use the angle that such side creates with the side of one of the three regular triangles that can be inscribed to such semi-regular nonagon. We consider the way in which convexity, possibility of construction, surface area, and other properties depend on a side of the semi-regular nonagon and angle φ=∡(a,b1).","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72602591","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 1
Heat and Mass Transfer on MHD Jeffrey-Hamel Flow in Presence of Inclined Magnetic Field 倾斜磁场作用下MHD杰弗里-哈默尔流的传热传质
IF 1 2区 数学 Q1 Mathematics Pub Date : 2020-06-18 DOI: 10.11648/j.acm.20200904.11
E. R. Onyango, M. Kinyanjui, M. Kimathi, S. M. Uppal
In this study, a magnetohydrodynamic Jeffrey-Hamel flow of a viscous, fluid that conducts electricity and is incompressible through a divergent conduit in presence of inclined variable magnetic field with heat and mass transfer has been investigated. The solutions of the governing equations of the MHD flow are obtained numerically since they are non-linear. The numerical scheme used is implemented in a computer software program and the results presented in graphical form. The velocity profile, the temperature profiles, the effect of variable magnetic field and of varying various dimensionless numbers on the flow are analyzed. Jeffrey-Hamel flows are also applied in the diffuser development. Some of the systems include; the channel between the compressor and gas turbine engine burner, the canal at departure from a gas turbine linked to the jet pipe, the canal subsequent to the impellor of a centrifugal compressor, wind tunnels with closed circuits, and water turbine draft tubes among several others. The results provide significant information for the improvement of proficiency and performance of technologies in aerospace, chemical, civil, environmental, industrial and mechanical applications.
在这项研究中,研究了一种粘性的、导电的、不可压缩的流体在倾斜变磁场存在下通过发散导管的磁流体动力学杰弗里-哈默尔流,并进行了传热传质。由于MHD流动的控制方程是非线性的,所以用数值方法求解。所使用的数值格式在计算机软件程序中实现,并以图形形式给出结果。分析了速度分布、温度分布、变磁场和各种无量纲数变化对流动的影响。杰弗里-哈默尔流也应用于扩散器的发展。一些系统包括;压气机和燃气轮机燃烧器之间的通道,燃气轮机与喷射管连接的通道,离心式压气机叶轮后的通道,封闭回路的风洞,水轮机引水管等。研究结果为提高航空航天、化学、民用、环境、工业和机械应用领域的技术熟练程度和性能提供了重要信息。
{"title":"Heat and Mass Transfer on MHD Jeffrey-Hamel Flow in Presence of Inclined Magnetic Field","authors":"E. R. Onyango, M. Kinyanjui, M. Kimathi, S. M. Uppal","doi":"10.11648/j.acm.20200904.11","DOIUrl":"https://doi.org/10.11648/j.acm.20200904.11","url":null,"abstract":"In this study, a magnetohydrodynamic Jeffrey-Hamel flow of a viscous, fluid that conducts electricity and is incompressible through a divergent conduit in presence of inclined variable magnetic field with heat and mass transfer has been investigated. The solutions of the governing equations of the MHD flow are obtained numerically since they are non-linear. The numerical scheme used is implemented in a computer software program and the results presented in graphical form. The velocity profile, the temperature profiles, the effect of variable magnetic field and of varying various dimensionless numbers on the flow are analyzed. Jeffrey-Hamel flows are also applied in the diffuser development. Some of the systems include; the channel between the compressor and gas turbine engine burner, the canal at departure from a gas turbine linked to the jet pipe, the canal subsequent to the impellor of a centrifugal compressor, wind tunnels with closed circuits, and water turbine draft tubes among several others. The results provide significant information for the improvement of proficiency and performance of technologies in aerospace, chemical, civil, environmental, industrial and mechanical applications.","PeriodicalId":55503,"journal":{"name":"Applied and Computational Mathematics","volume":null,"pages":null},"PeriodicalIF":10.0,"publicationDate":"2020-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76415942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 9
期刊
Applied and Computational Mathematics
全部 Acc. Chem. Res. ACS Applied Bio Materials ACS Appl. Electron. Mater. ACS Appl. Energy Mater. ACS Appl. Mater. Interfaces ACS Appl. Nano Mater. ACS Appl. Polym. Mater. ACS BIOMATER-SCI ENG ACS Catal. ACS Cent. Sci. ACS Chem. Biol. ACS Chemical Health & Safety ACS Chem. Neurosci. ACS Comb. Sci. ACS Earth Space Chem. ACS Energy Lett. ACS Infect. Dis. ACS Macro Lett. ACS Mater. Lett. ACS Med. Chem. Lett. ACS Nano ACS Omega ACS Photonics ACS Sens. ACS Sustainable Chem. Eng. ACS Synth. Biol. Anal. Chem. BIOCHEMISTRY-US Bioconjugate Chem. BIOMACROMOLECULES Chem. Res. Toxicol. Chem. Rev. Chem. Mater. CRYST GROWTH DES ENERG FUEL Environ. Sci. Technol. Environ. Sci. Technol. Lett. Eur. J. Inorg. Chem. IND ENG CHEM RES Inorg. Chem. J. Agric. Food. Chem. J. Chem. Eng. Data J. Chem. Educ. J. Chem. Inf. Model. J. Chem. Theory Comput. J. Med. Chem. J. Nat. Prod. J PROTEOME RES J. Am. Chem. Soc. LANGMUIR MACROMOLECULES Mol. Pharmaceutics Nano Lett. Org. Lett. ORG PROCESS RES DEV ORGANOMETALLICS J. Org. Chem. J. Phys. Chem. J. Phys. Chem. A J. Phys. Chem. B J. Phys. Chem. C J. Phys. Chem. Lett. Analyst Anal. Methods Biomater. Sci. Catal. Sci. Technol. Chem. Commun. Chem. Soc. Rev. CHEM EDUC RES PRACT CRYSTENGCOMM Dalton Trans. Energy Environ. Sci. ENVIRON SCI-NANO ENVIRON SCI-PROC IMP ENVIRON SCI-WAT RES Faraday Discuss. Food Funct. Green Chem. Inorg. Chem. Front. Integr. Biol. J. Anal. At. Spectrom. J. Mater. Chem. A J. Mater. Chem. B J. Mater. Chem. C Lab Chip Mater. Chem. Front. Mater. Horiz. MEDCHEMCOMM Metallomics Mol. Biosyst. Mol. Syst. Des. Eng. Nanoscale Nanoscale Horiz. Nat. Prod. Rep. New J. Chem. Org. Biomol. Chem. Org. Chem. Front. PHOTOCH PHOTOBIO SCI PCCP Polym. Chem.
×
引用
GB/T 7714-2015
复制
MLA
复制
APA
复制
导出至
BibTeX EndNote RefMan NoteFirst NoteExpress
×
0
微信
客服QQ
Book学术公众号 扫码关注我们
反馈
×
意见反馈
请填写您的意见或建议
请填写您的手机或邮箱
×
提示
您的信息不完整,为了账户安全,请先补充。
现在去补充
×
提示
您因"违规操作"
具体请查看互助需知
我知道了
×
提示
现在去查看 取消
×
提示
确定
Book学术官方微信
Book学术文献互助
Book学术文献互助群
群 号:481959085
Book学术
文献互助 智能选刊 最新文献 互助须知 联系我们:info@booksci.cn
Book学术提供免费学术资源搜索服务,方便国内外学者检索中英文文献。致力于提供最便捷和优质的服务体验。
Copyright © 2023 Book学术 All rights reserved.
ghs 京公网安备 11010802042870号 京ICP备2023020795号-1