一种基于校正无线电传播时间的室内三维定位模型

对室内终端进行基于无线通信基站的三维定位时,由于无线电在传播过程中,存在建筑物或树木遮挡、反射、折射等物理现象,导致基站到终端传播时间的测量值与精确值之间存在误差.为了减少上述误差对定位精度的影响,运用无线定位原理建立了一种基于校正无线电传播时间的改进的室内三维定位模型.通过对2016年全国研究生数学建模问题C题所提供的不同场景的数据分析,发现基站与终端无线电传播时间的测量值与其精确值之间存在线性关系,而且同一场景下近似有相同的线性关系,场景不同线性关系一般不同.基于这一现象,对基本的定位模型进行了合理的修正形成了改进的定位模型,数值实验表明改进的定位模型有很好的定位精度和鲁棒性.     

多基站下基于信号到达时间的室内三维定位

对基于无线电信号的到达时间(TOA)的定位技术进行了研究.首先,建立了TOA测量值与真实值间的函数关系,通过求解含惩罚项的非线性最小二乘问题实现终端定位和噪声估计,并在已有研究的基础上提出了Alternating Iterative Reweighting(AIR)算法;其次,利用基站之间的几何位置进行筛选,根据每个终端信息完成自适应的最少基站的选择及定位;并结合物理特性实现终端运动轨迹预测;最后,根据基站通信半径筛选出可被定位终端,完成定位精度与终端平均连接度数之间关系的建模.     

基于几何非协调分解的区域分解方法误差分析

对三维可压线弹性问题采用一种基于几何非协调分解的区域分解方法进行求解,证明了数值解具有最优误差估计.     

基于颜色和方向特征区域对比度的显著性检测模型

视觉显著性检测是很多计算机视觉任务的重要步骤,提出了一种基于颜色、方向特征和空间位置关系相结合的区域对比显著性检测算法.首先用基于图论的算法将图像分割成若干区域,结合区域间颜色特征和空间对比度计算出颜色显著图.同时采用基于纹理特征的算法分割图像,通过方向特征和空间对比度得到方向显著图.最后将二者结合得到最终显著图.在国际现有公开测试集上进行仿真实验,并与其它显著性检测方法进行对比,检测结果更加准确、合理,证明此算法切实可行.     

基于一种灰色综合关联模型的区域客运结构优化研究

为实现客运结构总体区域优化,运用灰色系统理论中的灰色综合关联分析模型,以珠三角地区客运结构为研究对象进行实证研究,建立了各种客运方式的旅客周转量与相关经济社会主要指标间的灰色综合关联矩阵,对客运结构系统特征及相关影响因素作优势分析.研究结论表明:城市化程度对客运结构影响最大;其次是人均可支配收入,再次是人均生产总值;人口总数对客运结构影响小,但对客运总量影响大.珠三角地区在中短途客运方面,应大力发展城市轨道交通(城际铁路和地下铁道);在长途客运方面,应大力发展高速铁路和民航.     

长三角区域经济一体化和经济收敛:基于空间杜宾面板模型

区域经济一体化是我国区域经济协调持续发展的长期趋势和重要手段.已有研究表明产业区域间推移有助于推进区域经济一体化,但没有考虑到邻近区域的空间相互作用及其影响.尝试将邻近空间溢出效应纳入到区域经济一体化及其区域经济增长差异收敛性.以泛长三角为典型区域进行了实证检验,空间杜宾模型的计量结果表明:未来2025年左右,长三角区域经济一体化融合程度达到一个新的发展阶段,区域内经济发展差异将缩小一半;长三角区域经济一体化存在显著的正向空间自相关性,区域内各个地区间的经济融合发展具有明显的空间集聚和邻近区域的空间溢出效应,且物质资本、城市化具有空间挤出效应;长三角区域经济增长差异存在条件收敛趋势,且具有正向空间自相关性,存在显著的经济一体化涓流效应.基于上述分析,提出长三角区域经济一体化的主要政策建议有:长三角区域内各级地方政府,建立以行政契约制度和磋商沟通机制为主要方式的地区性多元协调机制;充分发挥市场机制和企业主体作用,加快建设和培育现代服务业和先进制造业中心,推动产业城镇互动发展,形成区域融合重组的增长极轴.     

中国区域就业结构与区域收入差异的实证研究—基于panel-data模型

运用面板数据模型(Panel-data Model)分析了直辖市、东中西部三大产业的就业结构对区域收入差异的影响,不同区域的就业结构对区域的收入差异影响不同,针对不同区域情况,提出了协调发展产业,调整产业就业结构.促使区域差异缩小的政策建议.     

基于深度学习和水流调控算法的智能室内灭火系统研究

近些年,随着人民生活水平的不断提高以及高质量生活意识的不断增强,越来越多的家用电器通过线上购物的方式走进普通家庭.这些用电产品在给人民生活提供便利的同时,由于本身质量问题以及带来的电路高载荷问题也为人民生活埋下诸多火灾隐患.一旦引发室内火灾,将会对居民的生命财产安全带来极其严重的危害.目前常用的自动灭火系统虽能在一定程...     

基于函数凸性的变换区域舍选法在连续分布随机数中的应用

本文提出了基于函数凸性的变换区域舍选法算法 ,该方法可应用于产生具有凸性区间的密度函数随机数 .与一般舍选法相比 ,变换区域舍选法有较大的接受概率 ,能有效地提高舍选法效率 .     

基于HWSME的股票最佳投资区域起端的模糊综合评判方法

寻找进入主升浪的股票对投资效益最大化意义重大.讨论并界定了股票最佳投资区域,借助于HWSME和模糊综合评判,建立了股票最佳投资区域起端的模糊综合评判方法,构建了评价指标体系和隶属函数.通过对中国股票市场部分股票进行了横向和纵向预测实验,结果证明了方法的有效性.对投资效益最大化提供了强有力的分析工具.     

Sensitivity analysis in geometric programming: Theory and computations

This paper surveys the main developments in the area of sensitivity analysis for geometric programming problems, including both the theoretical and computational aspects. It presents results which characterize solution existence, continuity, and differentiability properties for primal and dual geometric programs as well as the optimal value function differentiability properties for primal and dual programs. It also provides an overview of main computational approaches to sensitivity analysis in geometric programming which attempt to estimate new optimal solutions resulting from perturbations in some problem parameters.     

Investigation of a macroeconomic model by the method of region analysis

A macroeconomic model on the relation between economic growth and the environment is investigated with the aim of illustrating how the method of region analysis can be used in solving practical problems formulated as regular optimal control problems with state constraints.This paper was written when the author was invited by Professor R. Bulirsch to work at the Munich University of Technology with the assistance of the Alexander Von Humboldt Foundation. The author would like to express his sincere gratitude to the Alexander Von Humboldt Foundation and to Professor Bulirsch.     

Pension funding problem with regime‐switching geometric Brownian motion assets and liabilities

This paper extends the pension funding model in (N. Am. Actuarial J. 2003; 7 :37–51) to a regime‐switching case. The market mode is modeled by a continuous‐time stationary Markov chain. The asset value process and liability value process are modeled by Markov‐modulated geometric Brownian motions. We consider a pension funding plan in which the asset value is to be within a band that is proportional to the liability value. The pension plan sponsor is asked to provide sufficient funds to guarantee the asset value stays above the lower barrier of the band. The amount by which the asset value exceeds the upper barrier will be paid back to the sponsor. By applying differential equation approach, this paper calculates the expected present value of the payments to be made by the sponsor as well as that of the refunds to the sponsor. In addition, we study the effects of different barriers and regime switching on the results using some numerical examples. The optimal dividend problem is studied in our examples as an application of our theory. Copyright © 2009 John Wiley & Sons, Ltd.     

Mathematical analysis of an influenza epidemic model,formulation of different controlling strategies using optimal control and estimation of basic reproduction number

In this article, a deterministic model is formulated to perform a thorough investigation of the transmission dynamics of influenza. In particular, our model takes into account the effects of medication as well as hospitalization. An in-depth stability analysis of the model is performed, and it is subsequently shown that the model is locally, as well as globally asymptotically stable, when R₀ > 1. It is also shown that there exists a unique endemic equilibrium whenever R₀ > 1. After estimating the effective contact rate, we estimate the basic reproduction number, using both an ordinary least squares and generalized least squares methodology. We also estimated confidence intervals for the effective contact rate using parametric bootstrapping. Furthermore, we perform uncertainty and sensitivity analysis to recognize the impact of crucial model parameters on R₀. In addition, using ideas from the optimal control theory, optimal medication and hospitalization strategies are proposed to eliminate the disease.     

A CLASS OF TRUST REGION METHODS FOR LINEAR INEQUALITY CONSTRAINED OPTIMIZATION AND ITS THEORY ANALYSIS Ⅱ. LOCAL CONVERGENCE RATE AND NUMERICAL TESTS

In this paper we prove that a class of trust region methods presented in part Ⅰ is superlinearly convergent. Numerical tests are reported thereafter. Results by solving a set of typical problems selected from literatures have demonstrated that our algorithm is effective.     

A theoretical model for Reynolds-stress and dissipation-rate budgets in near-wall region

A 3-D wave model for the turbulent coherent structures in near-wall region is proposed. The transport nature of the Reynolds stresses and dissipation rate of the turbulence kinetic energy are shown via computation based on the theoretical model. The mean velocity profile is also computed by using the same theoretical model. The theoretical results are in good agreement with those found from DNS, indicating that the theoretical model proposed can correctly describe the physical mechanism of turbulence in near wall region and it thus possibly opens a new way for turbulence modeling in this region.     

Parameter uncertainty, sensitivity analysis and prediction error in a water-balance hydrological model

Analysis of uncertainty is often neglected in the evaluation of complex systems models, such as computational models used in hydrology or ecology. Prediction uncertainty arises from a variety of sources, such as input error, calibration accuracy, parameter sensitivity and parameter uncertainty. In this study, various computational approaches were investigated for analysing the impact of parameter uncertainty on predictions of streamflow for a water-balance hydrological model used in eastern Australia. The parameters and associated equations which had greatest impact on model output were determined by combining differential error analysis and Monte Carlo simulation with stochastic and deterministic sensitivity analysis. This integrated approach aids in the identification of insignificant or redundant parameters and provides support for further simplifications in the mathematical structure underlying the model. Parameter uncertainty was represented by a probability distribution and simulation experiments revealed that the shape (skewness) of the distribution had a significant effect on model output uncertainty. More specifically, increasing negative skewness of the parameter distribution correlated with decreasing width of the model output confidence interval (i.e. resulting in less uncertainty). For skewed distributions, characterisation of uncertainty is more accurate using the confidence interval from the cumulative distribution rather than using variance. The analytic approach also identified the key parameters and the non-linear flux equation most influential in affecting model output uncertainty.     

Error estimation,adaptivity and data transfer in enriched plasticity continua to analysis of shear band localization

In this paper, an adaptive FE analysis is presented based on error estimation, adaptive mesh refinement and data transfer for enriched plasticity continua in the modelling of strain localization. As the classical continuum models suffer from pathological mesh-dependence in the strain softening models, the governing equations are regularized by adding rotational degrees-of-freedom to the conventional degrees-of-freedom. Adaptive strategy using element elongation is applied to compute the distribution of required element size using the estimated error distribution. Once a new mesh is generated, state variables and history-dependent variables are mapped from the old finite element mesh to the new one. In order to transfer the history-dependent variables from the old to new mesh, the values of internal variables available at Gauss point are first projected at nodes of old mesh, then the values of the old nodes are transferred to the nodes of new mesh and finally, the values at Gauss points of new elements are determined with respect to nodal values of the new mesh. Finally, the efficiency of the proposed model and computational algorithms is demonstrated by several numerical examples.     

各地区城市市政工程情况统计分析及评估

本文利用数学计算软件SAS作主成分分析 ,将我国各地区城市市政工程情况进行排序、分类 ,再用对应分析法分别对各地区进行单项指标分析 ,最后对影响各地区城市市政工程情况的几个重要因素进行相关分析。以期为各地区城市市政工程的健康发展提供更好的思路     

Minimization approach to membership evaluation in fuzzy sets and error analysis

Evaluation of the degree of membership in fuzzy sets is a fundamental topic in fuzzy set theory. Saaty (Ref. 1) proposes a method for solving this problem that has been widely accepted. In this paper, we examine the problem from an error minimization point of view that attempts to reflect the real intentions of the decision maker. When this approach is used, the findings reveal that fuzzy sets of different cardinalities have dramatically different requirements in the consistency level of the input data as far as the error minimization criterion is concerned.