Study on the Influence of Piloti on Mean Radiant Temperature in Residential Blocks by 3-D Unsteady State Heat Balance Radiation Calculation

Piloti is commonly used in tropical and subtropical climate zones to get high wind velocity and create shadowed areas in order to optimize the living environment of residential blocks, but there are few studies to reveal the influence of piloti on the radiant environment of residential blocks systematically. Taking the city of Guangzhou as an example, using 3-D Unsteady State Heat Balance Radiation Calculation Method, this paper shows that the mean radiant temperature (MRT) under piloti area increases with the increase of piloti ratio, and especially when piloti ratio is equal to 100％, the MRT increase trend becomes sharp. The MRT of exposed area decreases with the increase of piloti ratio, especially when piloti ratio reaches 100％, the decrease trend of MRT becomes sharp, which offers the reference for the study on piloti design in subtropical climate zones and further research on living environment by CFD simulation in residential blocks.     

复插值逼近从单位圆盘扩大到Jordan区域的边界充要条件

D是复平面上Jordan闭曲线Γ围成的单连区域.自20世纪40年代以来,在闭域D上用Hermite插值多项式一致逼近和平均逼近f(z)∈A(q)(D),已经有很多研究而且还在继续研究.大量作者接连不断地减少区域边界条件以期提高论文的水平.什么是最少的边界条件?直到现在,这个问题似乎还没有解决.本文已经发现并证明了:为了Hermite插值多项式收敛于f(z)∈A(q)(D—),其充分必要条件是Γ∈C~,即设这区域边界曲线Γ的参数表示是z=z(t),它具有一阶导数z'(t)连续且不等于零于[0,2π]上.     

混凝土坝实测性态的可变模糊综合评价

大坝实测性态综合评价是一个多层次、多指标的复杂评价问题.为此,建立混凝土坝实测性态综合评价体系,提出用均方连差拟定控制指标的方法,并将可变模糊集理论运用于评价中.从单测点建立模型,形成单层指标到多层指标的评价途径,对某混凝土坝的坝体变形进行了综合评价,其结果与监测报告一致,表明可变模糊评价方法运用于混凝土坝实测性态综合评价是合理可靠的.     

高维空间第一类曲面积分的计算及中值定理

目前的数学分析教材中,关于曲线积分和曲面积分的内容大多在三维欧氏空间中论述,对于高维空间中的曲面积分问题很少提及,而在许多工程应用中又需要在高维空间中计算曲面积分.讨论了高维欧氏空间中第一类曲面积分问题,推导出将光滑曲面的第一类曲面积分转化为重积分的一般公式,并将三维空间中的第一类曲面积分中值定理推广到高维的情况.     

积分中值定理的推广

本文首先对积分中值定理做了有益的改进,并对相应“中值点”的渐近性加以讨论。     

Statistical morphology and Bayesian reconstruction

The aim of this paper is to show that basic morphological operations can be incorporated within a statistical physics formulation as a limit when the temperature of the system tends to zero. These operations can then be expressed in terms of finding minimum-variance estimators of probability distributions. It enables us to relate these operations to alternative Bayesian or Markovian approaches to image analysis.We first show how to derive elementary dilations (winner-take-all) and erosions (loser-take-all). These operations, referred to as statistical dilations and erosion, depend on a temperature parameter =1/T. They become purely morphological as goes to infinity and become purely linear averages as goes to zero. Experimental results are given for a range of intermediate values of . Concatenations of elementary operations can be naturally expressed by stringing together conditional probability distributions, each corresponding to the original operations, thus yielding statistical openings and closings. Techniques are given for computing the minimum-variance estimators. Finally, we describe simulations comparing statistical morphology and Bayesian methods for image smoothing, edge detection, and noise reduction.     

炮弹发射弹道目标精度校正估计仿真

针对全球定位系统、雷达和卡尔曼滤波等传统测量手段在弹道量测中面临的诸多问题,提出了超宽带技术与平方根无迹卡尔曼滤波方法相结合的弹道估计算法,通过试验与仿真对该算法进行了分析.结果表明,采用平方根无迹卡尔曼滤波进行估计时,运行时间低于扩展卡尔曼滤波,略高于无迹卡尔曼滤波,且位置和速度均方根误差均低于二者.将平方根无迹卡尔曼滤波应用于弹道估计问题中可取得更为有效、准确的估计结果.     

基于模糊聚类算法的智能电网用户分类

随着智能电网建设的深入,许多智能仪表被接入电网以获取用户的实时负荷数据。由于用户数量众多,单独对个体进行数据处理和分析是不现实的,所以需要对用户进行分类。采用模糊聚类算法来处理负荷侧不同用户的用电负荷数据,随机抽取了某小区的25个用户数据,并对其用电行为进行了分类。结合聚类有效性指标得到了算法的最佳聚类数,并进行了仿真分析。结果表明,模糊聚类算法在负荷侧不同用户用电行为分类中有着较好的表现。     

三角形网格模型顶点曲率的求解算法*

推导了一般三角形网格模型顶点的平均曲率、高斯曲率和主曲率的计算方法,考虑到经常遇到粗糙三角形网格模型,为提高其曲率计算方法的精度,结合Loop细分曲面算法,进一步拓展了该曲率计算方法.该算法用于具有特征保持的网格模型简化取得了良好的效果.     

Investigation of fatigue crack initiation in Ti-6Al-4V during tensile-tensile fatigue

Fatigue crack initiation in Ti-6Al-4V has been investigated in high cycle fatigue (HCF) and low cycle fatigue (LCF) regimes at stress ratio R=0.1 using the replication technique. In all four tested α/β microstructures, the crack was initiated by fracture of equiaxed alpha grain. Fractured alpha grains are seen on the fracture surface as flat facets with features characteristics of cleavage fracture. In the regime of low stress amplitudes and in the absence of reverse loading, cleavage fracture contributes to crack initiation and early stages of crack growth in Ti-6Al-4V. This mechanism is discussed in relation to the anomalous mean stress fatigue behavior exhibited by this alloy.