基于GIS与虚拟现实技术的土地整理规划研究

以湖北省赤壁市赤壁片土地整理规划为例,利用GIS(地理信息系统)与VR(虚拟现实技术)进行的土地整理规划,将实地测量数据在ArcGIS软件中进行数字化处理,采用GIS建立DEM(数字高程模型),同时将各种单体工程用三维制图软件3D MAX建模,并将3D模型嵌入在规划后的DEM中,获得规划后的虚拟场景,判断规划的合理性,同时对规划进行调整并加以完善.结果表明,基于GIS和VR技术进行土地整理规划,增强了规划后虚拟场景的仿真性,提高了土地整理规划结果的科学性.     

Optimization of elastic material parameters of sheet metal with FEMU and DIC

In this paper a deep-drawing sheet steel is characterized through tensile tests with samples taken in different angles to the rolling direction. The displacement field is recorded with an optical full-field measurement system and the deformation field is calculated by Digital Image Correlation (DIC). The orthotropic elastic material parameters are identified through an iterative parameter optimization via Finite Element Model Updating (FEMU). In this procedure the material parameters are modified in every iteration so that the numerically computed deformation field and forces match the measured values as well as possible. Depending on the objective function and the input values used in the optimization routine, global or only local minima exist. To show the convergence of the applied technique, two different optimization algorithms, one gradient-based and one gradient-free with different initial starting points were used. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

A comparison of regime-switching temperature modeling approaches for applications in weather derivatives

A comparison of regime-switching approaches to modeling the stochastic behavior of temperature with an aim to the valuation of temperature-based weather options is presented. Four models are developed. Three of these are two-state Markov regime-switching models and the other is a single-regime model. The regime-switching models are generated from a combination of different underlying processes for the stochastic component of temperature. In Model 1, one regime is governed by a mean-reverting process and the other by a Brownian motion. In Model 2, each regime is governed by a Brownian motion. In Model 3, each regime is governed by a mean-reverting process in which the mean and speed of the mean-reversion remain the same, but only the volatility switches between the states. Model 4 is a single-regime model, where the temperature dynamics are governed by a single mean-reverting process. All four models are utilized to determine the expected heating degree days (HDD) and cooling degree days (CDD), which play a crucial role in the valuation of weather options. A four-year temperature dataset from Toronto, Canada, is used for the analysis. Results demonstrate that Model 1 captures the temperature dynamics more accurately than the other three models. Model 1 is then used to price the monthly call options based on a range of strike HDD.     

Forest fire modelling using cellular automata: application to the watershed Oued Laou (Morocco)

ABSTRACT

In this work, we consider the problem of modelling the phenomenon of forest fires using the cellular automata approach. The proposed model takes into account the main parameters that affect this phenomenon like nature and density of vegetation, humidity, wind, and altitude. We developed a decision-aided tool with JAVA which allows to analyse and format several hybrid collected data (satellite images, Digital Terrain Model) relatively to each studied area. The generated scenarios of forest fire spread in the study area will be considered as a guide for strategies in control and prevention of forest fires. As an application, we consider the watershed Oued Laou (Morocco).     

矩形宏单元B-I模型与板结构的影响面

本文首次建立了矩形宏单元的B-Ⅰ模型,比现有模式更具实用价值及灵活性.为建立薄板内力R的影响面,文中定义了诸相应的广义分布荷载q.算例表明,本文提出的模型及广义荷载公式具有计算精度高,占用内存少等优点,对承受移动荷载的板结构,诸如双向连续桥面板,高桩码头无梁板等效果尤为突出.     

RISK-BASED MULTIATTRIBUTE DECISION-MAKING IN PROPERTY AND WATERSHED MANAGEMENT

ABSTRACT. Determining best management systems for properties and evaluating their sustainability at the watershed scale are useful and important aspects of integrated watershed management. Multiattribute decision-making (MADM) is very useful for modeling the selection of best management systems for properties in a watershed. This paper reviews four MADM approaches including utility theory, surrogate worth tradeoff, free iterative search and stochastic dominance with respect to a function (SDWF). Emphasis is on determining how the first three methods could be used to determine the best (most preferred) combinations of attributes and associated management systems for a property. An application of the expected utility method with risk neutral preferences is presented in which farmer's preferences for five attributes are used to rank five farming systems for an agricultural watershed in Missouri. A framework is presented for assessing the sustainability of the best management systems for all properties in a watershed and the cost-effectiveness of policies for enhancing sustainable resource management at the watershed scale.     

Time series analysis of covariance based on linear transfer function models

In this article, a time series analysis of covariance model is introduced when covariates time series have lead–lag relationship with response time series. Parameter estimation and hypothesis testing for this model are made in spectral domain. We provide an instruction for our approach using a real Hydrological time series data set.

     

投资者心态对股票价格走势的作用机理研究

假设股价变化遵循马尔科夫转移过程,考察具有不同心态的投资者的市场行为,给出投资者心态与股价变化之间相互作用的模型,得到了股价走势的两个基本模式,并用此模型解释股价走势中的动量效应和反转效应.     

Courant type approximations and their wavelet decomposition

Courant type functions (not necessarily piecewise linear) are considered, and a wavelet decomposition of the corresponding embedded spaces is constructed. Model examples are presented. Bibliography: 9 titles. Illustrations: 2 figures. __________ Translated from Problemy Matematicheskogo Analiza, No. 37, 2008, pp. 3–22.     

GPM(1,1,m)模型及其在中国能源消费预测中的应用

客观准确地预测能源消费,可以为政府制定社会经济发展政策提供重要参考.利用矩阵分析的思想研究了灰色预测模型的建模机理,提出了基于时间多项式的可拓形式GPM(1,1,m)模型,并分析了其理论意义.在此基础上,通过研究了时间多项式对模型参数和预测值的影响,推导了它们之间的定量关系,设计了实际建模中的优化方法和参数估计的一般形...     

平行数据模型中异方差问题的处理——截面内误差项U_(it)～ARCH(q)

本文在平行数据模型方差成分的框架下,考虑了横截面内误差项Uit～ARCH(q)的异方差处理方法.给出模型设定的假设检验和参数的一致估计,并利用Monte-Carlo方法验证了本文估计方法优于普通最小二乘估计方法.     

变参数非等间距GM(1,1)模型及应用

在对非等间距序列建模时,考虑到序列本身的特点,结合GM(1,1)模型的建模过程,提出了一种对非等间距序列建立变参数GM(1,1)模型的方法,并将其应用于具体实例进行分析,计算结果表明本文提出的方法具有较高的精度,从而为解决非等间距序列的拟合及预测问题提供了一种比较好的思路.     

平行数据模型中异方差问题的处理——截面内误差项v_(it)～ARCH(q)

本文在平行数据模型方差成分的框架下,考虑了横截面内误差项v_(it)～ARCH(q)的异方差处理方法。给出模型设定的假设检验和参数的一致估计,并利用Monte-Carlo方法验证了本文估计方法优于普通最小二乘估计方法。     

A Scharfetter–Gummel Type Discretization of the Quantum Drift Diffusion Model

We derive a generalized Scharfetter–Gummel discretization of the Quantum Drift Diffusion Model in one space dimension. The scheme relies on the introduction of a generalized potential which identifies the quantum drift term. Further, the new scheme is stable in the semiclassical limit recovering the SG scheme for the classical drift diffusion equations. Numerical results for a ballistic diode are presented.     

基于跳扩散过程的数据选择权定价

本文在风险中性原理下研究基于跳扩散过程的数据选择权定价问题,推导了标的资产价格服从跳扩散过程的数据选择权的定价公式。     

判别分析在基因剪切位点识别中的应用

基因的结构预测是目前极为活跃的研究领域,而基因剪切位点的识别则是基因结构预测中的重要环节.本文采用自己提出的平均似然比等方法,同时采用目前较为有效的权重矩阵(WMM)、最大相关分解(MDD)、动态规划等模型,充分提取剪切位点信号区的统计特征,采用统计中判别分析的方法进行判别,得到了较好的判别效果,并与其它方法进行了比较.     

层次分析法与人工智能相互关系的比较研究

以解决和分析宏观、复杂决策问题为主要特点的AHP方法同以解决具体、微观问题的专家系统之间有本质的联系。本文从分析和比较二者的特点出发,将不同层次的决策知识形式化地统一表示成IF-THEN型的规则,通过引入MYCIN系统中的不精确推理,来推导出所要排序的结论。这种推理与AHP中的合成算法有类似之处,但由于AHP合成时忽略了同层元素间不可避免的相关性,因而,二者在证据对结论支持的量值上略有不同。可是,在通常情况上不会导致排出次序的变化。此外,本文中所建议的方法对于准则层元素之间如果存在“与”或“或”的关系时,用推理的方法仍可求出不同的排序结果,这无疑在实际应用中具有相当的实用价值。本文所提出的方法除了保留原AHP的特点外,还对“定性推理”所需的知识获取过程有重要意义,而且,它为利用深层知识来解释浅层知识开辟了一条途径。     

Intelligent control of time-varying dynamical systems using CMAC artificial neural network

In this paper, some successful case studies are presented on the intelligent control of time-varying linear/nonlinear dynamical systems using the Cerebellar Model Arithmetic Computer (CMAC) artificial neural network, and a recently developed unified linear system theory and a novel control technique called Extended-Mean Assignment Control (EMAC). Thanks to CMAC's simple and effective training algorithm and fast learning convergence, satisfactory and encouraging simulation results of angle-of-attack control of an aerobreak re-entry spacecraft and attitude control of an earth orbiting space vehicle subject to gravity gradient torque are obtained and presented in this paper. Suggestions for further investigations on the control of time-varying dynamical systems using CMAC and EMAC are proposed.     

Digital planarity—A review

Digital planarity is defined by digitizing Euclidean planes in the three-dimensional digital space of voxels; voxels are given either in the grid-point or the grid-cube model. The paper summarizes results (also including most of the proofs) about different aspects of digital planarity, such as supporting or separating Euclidean planes, characterizations in arithmetic geometry, periodicity, connectivity, and algorithmic solutions. The paper provides a uniform presentation, which further extends and details a recent book chapter in [R. Klette, A. Rosenfeld, Digital Geometry—Geometric Methods for Digital Picture Analysis, Morgan Kaufmann, San Francisco, 2004].