208,664 research outputs found

    Analysis and Application of Panel Data Model

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    随着人们生活和经济活动的日益复杂,以及信息技术的不断发展,相比较传统横截面数据和时间序列,面板数据更能反映人们复杂的行为和数据背后的深层含义,对面板数据模型的分析和研究成为科研工作者关注的新热点。面板数据是包含多个时间序列截面的数据,因此它也比横截面数据和时间序列包含了更多的现实意义和内涵。 本文对面板数据静态模型和动态模型进行了研究,着重讨论了各个模型的参数估计,在不同的模型下利用合适的估计方法得到对参数的一致无偏估计。在静态模型中加入滞后项,得到了面板数据的动态模型,对两类模型的对比分析发现,由于滞后项和变量之间存在相关性,静态模型中的估计方法并不完全适用于动态模型。然后本文对非平稳面板...With the increasing complexity of people’s lives and economic activities, and the continuous development of information technology. Compared to traditional cross sectional data and time series,panel data better reflect the deep meaning of people behind complex behavior and data. The analysis and research on the panel data model has become a new hot spot for scientific research workers. Panel data ...学位:理学硕士院系专业:数学科学学院_应用数学学号:1902014115262

    Fitting mixed Erlang densities under Roughness Penalty

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    在统计学中,如何较好地拟合一组给定数据的密度函数并给出密度曲线的参数形式一直备受关注。尤其是实际问题中经常遇见的删失数据和多峰数据的拟合,不但要求密度曲线具有高度的灵活性,而且不能出现过度拟合现象,这就大大增加了拟合难度。其中,对于混合模型的研究越来越受到人们的重视,是因为混合模型是一种介于参数方法与非参数方法间的半参数模型,这种半参数模型的优越在于它既避免了参数模型对数据结构的拟合偏离问题又具有分布函数可知等非参数模型无法具备的拟合性质。继Tijims[2]给出证明,在弱收敛的意义下,具有相同尺度参数的混合Erlang模型可以无限逼近任意分布后,利用混合Erlang模型解决金融、保险等行业的...In statistics, the problem of how to give the density function of given data well by mathematical expression has drawn too much attention. Especially when it comes to the censored data or multi-mode data, the density curve needs not only be of high flexibility but also can get rid of overfit, which greatly increase the difficulty of fitting.Among them, the development of mixed model has received p...学位:理学硕士院系专业:数学科学学院_概率论与数理统计学号:1902014115262

    Varying-coefficient Panel Data Models with Cross-sectional Dependence: Estimation and Specification Testing

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    由于可以有效地控制不可观测的个体异质性和为更现实的行为假设建模等优势,面板数据模型被广泛地应用到经济学和金融学等领域的实证研究中。然而,传统的面板数据模型假设模型具有参数线性形式并且各个截面个体是相互独立的。参数线性假设可能造成模型误设。截面独立的假设经常与现实不符。为了解决上述问题,本论文提出了一类具有截面相关的变系数面板数据模型。同时,为了判断在实证分析中是否应该使用本论文提出的变系数模型,我们构造了检验变系数面板数据模型系数稳定性的检验统计量。论文主体共包括三个部分,其具体安排如下: 首先,我们建立了一类变系数异质面板数据模型,其自变量、平滑变量和误差项存在通过共同因子结构引入的截...Panel data models are widely used in many disciplines, such as economics, finance, due to the ability to control for the unobservable individual heterogeneity and model more realistic behavioral hypotheses. However, classical panel data models focus on the parametric linear specification of regression relationship and assume independence among different individuals. It is known that the parametric...学位:经济学博士院系专业:王亚南经济研究院_数量经济学学号:2772011015402

    Detection of Gene Regulatory Relationships based on ODE Model with Continuous Time-Lag

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    多年来,基因之间调控关系的识别研究层出不穷。本文主要提出带有连续延时的常微分方程模型来刻画两两基因之间的调控关系,然后进行模拟数据试验,并用此模型判别真实的两两基因对之间是否有调控关系。 首先,我们建立了带有连续延时的常微分方程模型;其次,基于真实实验数,我们模拟生成有调控关系以及没有调控关系的基因对数据;然后,我们将模拟数据代入我们提出的带有连续延时的ODE模型中并求解相关参数,再选取相应特征对判别基因对之间是否有调控关系的SVM分类器进行训练与测试,我们得到测试准确率高达89.5%;再次,我们比较了所提出的模型和线性模型应用在相同模拟数据上的结果的优劣,得到我们提出的模型能更好地刻画基因...Over the past years, there are many studies on the detection of regulatory relationships between genes. This paper mainly proposed an Ordinary Differential Equation model with continuous time-lag to describe the relationships between genes, then did simulations and predicted whether two genes of real data have the regulatory relationship. Firstly, we construct an Ordinary Different...学位:理学硕士院系专业:数学科学学院_计算数学学号:1902014115260

    Numerical and mathematical analysis of some combustion and phase separation models

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    本文先后讨论了两类自由边界问题:热-扩散燃烧模型和高阶广义Cahn-Hilliard方程,并针对这两类问题进行稳定性分析和数值模拟。 (I)热-扩散燃烧模型: 该模型描述了在二维带型区域中,零阶反应和分段温度动力机制的预混火焰热-扩散燃烧现象,模型表示为: 我们针对自由边界的胞状不稳定情况(即Lewis数满足0In this thesis, we will successively consider two free-interface problems: one is a thermo-diffusive combustion model, the other is a higher-order generalized Cahn-Hilliard equation. In both cases, we are interested in the stability analysis and numerical simulations. (I) Thermo-diffusive combustion: The problem models a thermo-diffusive combustion of premixed flame with zero-order reac...学位:理学博士院系专业:数学科学学院_计算数学学号:1902013015416

    Research on Reservoir Prediction Automatic Optimization Model Based on Seismic Data

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    地震数据中蕴含着丰富的有关地下的地质构造、底层岩性和流体物性等信息,是储层预测的数据基础。但随着我国油气勘探开发的水平越来越高和勘探领域的不断延伸,地震属性数量和种类膨胀式增长,储层预测难度增大。数据挖掘是一种有效进行储层预测手段。本文基于数据挖掘中的特征降维方法和聚类分析构造了储层预测模型。 基于数据挖掘的储层预测模型在实际使用中经常需要人工设置参数。如果使用者不了解数据挖掘技术,设置参数是一个困难的事。储层预测模型参数选择的好坏对其预测结果有很大影响。储层预测模型一般会有多个参数,有的参数变化范围比较大,模型参数取值组合很多,人工寻找模型最佳参数很耗费时间。本文提出一个储层预测模型参数自...The seismic data contains abundant information of stratigraphic lithology, fluid physical properties and geological structure. The information about reservoir property and lithology which is effectively extracted from seismic data has very strong practicability. However, with the development of oil-gas exploration development in our country and the constant extension of exploration fields. The nu...学位:工学硕士院系专业:软件学院_计算机科学与技术学号:2432014115239

    A mixed of Erlang autogressive conditional duration model with an application to high-frequency data analysis

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    随着信息技术的发展,金融高频数据的分析工作越来越被重视。而条件自回归持续期(ACD)模型在处理金融高频数据的正值时间序列方面,有着重要的作用。普遍情况下,持续期模型的新息多在0附近大密度聚集,并呈现非对称的厚尾分布,因此具有厚尾形状的分布越来越多地被统计学家们应用于ACD模型中。事实上,历史上将指数分布、Weibull分布、广义伽马分布等分布作为新息分布的ACD模型已能够处理大部分高频数据,但这些模型存在一个共同的不足,就是对模型新息序列的拟合效果都不是很好,此时模型参数的估计只能是拟最大似然估计。因此对于数据量不断增大数据结构愈趋复杂的金融高频数据,我们仍需寻求更具灵活性的分布函数来拟合持续...With the development of information technology, more and more attention has been paid to financial high-frequency data analysis. The autoregressive conditional duration (ACD) model plays an important role in dealing with the positive time series of financial high-frequency data. In the general case, the error of the duration model is dense in the vicinity of 0, and presents an asymmetric heavy-tai...学位:理学硕士院系专业:数学科学学院_概率论与数理统计学号:1902014115261

    Partially Linear Spatial Lag Panel Model with Fixed Effects

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    传统的计量经济学,忽略了地理空间邻近引起的数据空间相依性和空间异质性,可能导致模型估计方法和检验结果的失效或偏差。预先设定参数形式的空间计量模型具有较为强烈的主观性,对一些具体的计量问题,不足以充分刻画被解释变量和解释变量之间的潜在关系。因此本文试图构建一类半参数空间滞后面板模型,并对其估计量性质进行必要的理论推导和数值模拟验证。 Yu,Jong&Lee(2008)研究了固定效应空间动态面板数据模型的拟极大似然估计量的大样本性质,Su&Jin(2010)研究了一类部分线性空间自回归模型的截面拟极大似然估计量。在此基础上,本文构建了一类部分线性固定效应空间滞后面板模型,在此模型中,综合考虑了固...Traditional econometrics ignore the spatial dependency and spatial heterogeneity caused by the geospatial proximity, which may lead to the failure or deviation of the methods and test results. However, the parametric spatial measurement models with pre-set parameters have a strong subjectivity. For some specific measurement problems, they are not enough to fully describe the potential relationship...学位:经济学硕士院系专业:经济学院_统计学学号:1542014115199

    Estimation of Varying-Coefficient Spatial Auto-Regression Panel Model with Random Effects

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    具有良好可读性和稳健性的变系数模型在各学科领域应用广泛。本文构建了一种新的随机效应变系数空间自回归面板模型,运用截面极大似然估计方法,导出了模型的估计量,证明其具备一致性和渐近正态性,蒙特卡洛模拟研究显示估计量的小样本表现效果良好。Varying coefficient models with superior readability and robustness have been widely used in a variety of research fields. In this paper, it proposes the new varying coefficient spatial autoregrcssive panel model with random effects. By the profile maximum likelihood estimators are constructed, it gets the consistency and asymptotical normality of these estimators. The Monte Carlo simulation shows that the estimators have good performances under finite samples.本文为国家社会科学基金项目“半参数变系数空间自回归模型的理论及应用研究”(16BTJ018)、教育部人文社会科学重点研究基地重大项目“集聚经济下的中国地方政府财税行为研究”(15JJD790029)、教育部人文社会科学项目“空间自回归单指数模型的理论和实践”(13YJA9100002)和福建省自然科学基金项目“几类新的变系数空间白回归模型的估计和应用研究”(2017J01396)的阶段性成果
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