曲线梁桥地震分析中的合理建模

为精确、快捷地模拟曲线梁桥在地震荷载作用下的反应,研究了曲线梁桥的合理建模方法,探讨了普通梁单元建模的可能性。通过SAP2000,以一曲线梁桥为对象分别采用厚板单元,普通梁单元,带质量惯性矩的梁单元建立了相应计算模型进行地震计算。计算结果表明,通过将普通梁单元放置主梁形心位置并采用无质量刚臂单元连接梁底支座的方法建立模型与厚板单元建模结果相近,满足精度要求,可应用到实际工程中。

初中数学建模教学初探

一提起数学,人们会想到它的抽象和复杂,感觉数学比较枯燥无味。但人们的日常生活离不开数学,人们每天的收入、支出和工作都需要用到数学,数学具有广泛的应用性。数学的产生就是为了解决现实世界中的问题,当然有大量的问题由于当时社会的局限性,用数学一时难以进行解决,但随着科学技术的发展,特别是计算机技术的进步,新的数学方法能够对这些现实问题进行解答,数学的应用越来越广泛。比如数学建模的产生,对日常生活中的一些问题能够进行方便有效的解决,它建立起了数学与现实世界的桥梁。

复杂山地风电场机位湍流分析研究

大湍流易增加风电机组的疲劳载荷,造成风电机组的损坏。为准确评估风电项目中各机位点的湍流值,避免因湍流误评导致机位废弃或机型选择不当,以江西某风电场及广东某风电场实际工程为例,从复杂地形的特殊风况、软件适应性及不合理模拟建模3个方面,分析了机位湍流偏大或失真的内在机理,并提出提高机位湍流仿真模拟计算精度的对策。

“将军饮马问题——线段和最短”教学设计和反思

好的引入是一堂课的“敲门砖”,笔者尝试追根溯源,从将军饮马的故事引出课题,激发学生学习兴趣.转化思想是初中数学重要思想之一,合理转化,可以化难为易,化繁为简.将军饮马问题是将两点在直线同侧的问题转化为两点在直线异侧的问题,但图形复杂时,学生很难把将军饮马问题从图形中抽离,所以学会识模、合理建模成为解题的关键.通过讨论、总结、归纳模型特征,达到巩固模型、掌握模型的目的.

Modeling of Mass Transfer in Nonideal Multicomponent Mixture with Maxwell-Stefan Approach

The Intalox metal tower packing was used to simulate an industrial relevant extractive distillation column for purifying azeotropic multicomponent mixture.In order to explain the inconsistencies in the modeling of transfer process in nonideal multicomponent distillation column,a method was developed with equilibrium stage models(EQ)and non-equilibrium model(NEQ)incorporated with Maxwell-Stefan diffusion equations in the framework of AspenONE simulator.Dortmund Modified UNIFAC(UNIFAC-DMD)thermodynamic model was employed to estimate activity coefficients.In addition,to understand the reason for the diffusion against driving force and the different results by EQ and NEQ models,explicit investigations were made on diffusion coefficients, component Murphree efficiency and mass transfer coefficients.The results provide valuable information for basic design and applications associated with extractive distillation.

Research on Compress or Modeling Methods

This article describes some of the common modeling method on compressor： black-box model, theoretical model, hybrid model and so on. It compares them, pointing out its advantages and disadvantages. In order to improve the design of the compressor and its performance, this paper proposes a new modeling theory. In this model, when you make the curve fitting between multiple variables, variables can be divided into many groups. Firstly, looking for the relationship between the variables in groups, and then you can find the relationship between aggregated group.

MODELING AND SIMULATION OF COMPOUND CLUTTER FOR COASTAL ENVIRONMENT

This paper introduces a novel clutter power model of coastal compound and deduces the statistic characteristics and the arithmetics of model parameter estimation algorithm. Then, a novel coastal compound distributed model of the clutter amplitude is proposed and its statistic character- istics are studied. Subsequently, the nonlinear relation of autocorrelation function is deduced between the coastal compound clutter random sequences and the correlated Gaussian random sequences, which is the important prerequisite for the clutter simulation based on the ZMNL (Zero Memory NonLin- earity). Lastly, the advantage of the algorithm is demonstrated by a feasible simulation of the gen- eration of the random coastal compound clutter sequences.

Modeling and Multi-objective Optimization of Refinery Hydrogen Network

The demand of hydrogen in oil refinery is increasing as market forces and environmental legislation, so hydrogen network management is becoming increasingly important in refineries. Most studies focused on single-objective optimization problem for the hydrogen network, but few account for the multi-objective optimization problem. This paper presents a novel approach for modeling and multi-objective optimization for hydrogen network in refineries. An improved multi-objective optimization model is proposed based on the concept of superstructure. The optimization includes minimization of operating cost and minimization of investment cost of equipment. The proposed methodology for the multi-objective optimization of hydrogen network takes into account flow rate constraints, pressure constraints, purity constraints, impurity constraints, payback period, etc. The method considers all the feasible connections and subjects this to mixed-integer nonlinear programming （MINLP）. A deterministic optimization method is applied to solve this multi-objective optimization problem. Finally, a real case study is intro-duced to illustrate the applicability of the approach.

A GAUSSIAN MIXTURE MODEL-BASED REGULARIZATION METHOD IN ADAPTIVE IMAGE RESTORATION

A GMM (Gaussian Mixture Model) based adaptive image restoration is proposed in this paper. The feature vectors of pixels are selected and extracted. Pixels are clustered into smooth,edge or detail texture region according to variance-sum criteria function of the feature vectors. Then pa-rameters of GMM are calculated by using the statistical information of these feature vectors. GMM predicts the regularization parameter for each pixel adaptively. Hopfield Neural Network (Hopfield-NN) is used to optimize the objective function of image restoration,and network weight value matrix is updated by the output of GMM. Since GMM is used,the regularization parameters share properties of different kind of regions. In addition,the regularization parameters are different from pixel to pixel. GMM-based regularization method is consistent with human visual system,and it has strong gener-alization capability. Comparing with non-adaptive and some adaptive image restoration algorithms,experimental results show that the proposed algorithm obtains more preferable restored images.

Seismic rock physical modelling for gas hydrate-bearing sediments

There are ambiguities and uncertainties in the recognition of gas hydrate seismic reflections and in quantitative predictions of physical information of natural gas hydrate reservoirs from seismic data. Rock physical modelling is a bridge that transforms the seismic information of geophysical observations into physical information, but traditional rock physics models lack descriptions of reservoir micro-structures and pore-filling materials. Considering the mineral compositions and pore microstructures of gas hydrates, we built rock physical models for load-bearing and pore-filling gas hydrate-bearing sediments,describe the mineral compositions, pore connectivity and pore shape using effective media theory, calculated the shear properties of pore-filling gas hydrates using Patchy saturation theory and Generalized Gassmann theory, and then revealed the quantitative relation between the elastic parameters and physical parameters for gas hydrate-bearing sediments. The numerical modelling results have shown that the ratios of P-wave and S-wave velocities decrease with hydrate saturation, the P-wave and S-wave velocities of load-bearing gas hydrate-bearing sediments are more sensitive to hydrate saturation, sensitivity is higher with narrower pores, and the ratios of the P-wave and S-wave velocities of pore-filling gas hydrate-bearing sediments are more sensitive to shear properties of hydrates at higher hydrate saturations. Theoretical analysis and practical application results showed that the rock physical models in this paper can be used to calculate the quantitative relation between macro elastic properties and micro physical properties of gas hydrate-bearing sediments, offer shear velocity information lacking in well logging, determine elastic parameters that have more effective indicating abilities, obtain physical parameters such as hydrate saturation and pore aspect ratios, and provide a theoretical basis and practical guidance for gas hydrate quantitative predictions.

Reality-Virtuality Fusional Campus Environment:An Online 3D Platform Based on OpenSimulator

This paper presents a reality-virtual fusional campus environment.It is an online 3D platform with some aspects of real information merged together.The whole platform is based on OpenSimulator with detailed geo-models to represent the university campus.Some preliminary experiments were done to integrate the realistic information with the virtual campus for making the geo-environment not only with detailed indoor and outdoor models,but also with the real representations of the physical world.The overall motivation is to provide a framework with strong support for reality-virtuality fusional modeling in a collaborative 3D online platform for research purposes.

Composite Waves for a Cell Population System Modeling Tumor Growth and Invasion

In the recent biomechanical theory of cancer growth,solid tumors are considered as liquid-like materials comprising elastic components.In this fluid mechanical view,the expansion ability of a solid tumor into a host tissue is mainly driven by either the cell diffusion constant or the cell division rate,with the latter depending on the local cell density(contact inhibition) or/and on the mechanical stress in the tumor.For the two by two degenerate parabolic/elliptic reaction-diffusion system that results from this modeling,the authors prove that there are always traveling waves above a minimal speed,and analyse their shapes.They appear to be complex with composite shapes and discontinuities.Several small parameters allow for analytical solutions,and in particular,the incompressible cells limit is very singular and related to the Hele-Shaw equation.These singular traveling waves are recovered numerically.