基于小波和侧抑制网络的红外图像增强算法

针对红外图像存在的对比度差、信噪比低等问题,提出了一种基于小波和侧抑制网络的红外图像对比度增强算法.该算法首先利用小波变换法对图像进行小波分解,然后分别采用优化局部阈值和侧抑制网络法对分解后的高频系数和低频系数进行处理,最后进行小波重构,即得到增强后的图像.实验表明:该算法能够在实现图像增强的同时,较好地抑制图像噪声,...     

关于多项式小分数部分的一个注解

设f(x)为任意一实系数多项式,N.G.Moshchevitin在他的文章[8]中给出了集合{α∈R∶ limn→∞ infnlog n‖af(n)‖＞0}的Hausdorff维数的下界.在本文中,我们延用文[8]的方法并结合齐次Moran集的维数理论给出这个集合Hausdorff维数的精确值.     

Analysis of some new partition statistics

We study several statistics for integer partitions: for a random partition of an integer n we consider the average size of the smallest gap (missing part size), the multiplicity of the largest part, and the largest repeated part size. Furthermore, we estimate the number of gap-free partitions of n. 2000 Mathematics Subject Classification Primary—05A17; Secondary—11P82 Dedicated to Helmut Prodinger on the occasion of his 50th birthday P.J. Grabner is supported by the START-project Y96-MAT of the Austrian Science Fund. This material is based upon work supported by the National Research Foundation under grant number 2053740.     

激光涂层零件的多冲碰撞形变效应与分析

报道了多冲碰撞载荷下激光涂层零件塑性变形现象。利用坐标网格法、显微分析法等分析了激光涂层零件的多碰累积变形现象和规律。这种塑性变形在常温即可发生,且具有低应力和累积特性。变形发生在涂层表面及以下一段区域内,并由大到小呈梯度变化。碰撞能量驱动、冲击温升效应、晶界滑动与迁移、亚结构的形成与孪晶等,是引起多碰累积变形的可能原因。     

在PCB中集成光数据流的制造

介绍了在PCB中采用埋入光互连波导形成集成光数据流的技术。     

On the fractional parts of the natural powers of a fixed number

Let ξ ≠ = 0 and α > 1 be reals. We prove that the fractional parts {ξ αⁿ}, n = 1, 2, 3, ..., take every value only finitely many times except for the case when α is the root of an integer: α = q ^1/d, where q ≥ 2 and d ≥ 1 are integers and ξ is a rational factor of a nonnegative integer power of α.     

局部包络片控制误差简化三角网格模型

利用内外包络控制三角网格模型简化误差是一种可行的方法.但构造整个模型的内外包络需要花费较多的时间,且每次简化操作时也会进行大量重复的三角形相交检测,使算法效率下降.针对这些问题,本文提出了局部包络片控制误差的思想,即每次简化操作仅利用相关部分的包络来控制误差.算法采用三角形收缩操作简化模型,当原始模型上的一个三角形被选中,并尝试进行收缩操作时,先构造其对应的局部包络片;在该三角形收缩后,原来与之相邻的三角形将发生形变,若这些形变后的三角形位于局部包络片之间,则认为此次三角形收缩操作可以接受,否则予以取消.实验结果表明,局部包络片保持了良好的误差控制效果,且由于构造简单,很少发生自交现象,减少了三角形相交检测次数,提高了计算效率.     

波峰焊机用三相异步感应式电泵的研究

开发出一种用三相异步感应泵波峰发生器的全自动单／双波峰焊机替代机械泵式波峰焊机，无任何转动部件，无磨损，免维护，提高了整机可行性。     

Minimax estimators that shift towards a hypersphere for location vectors of spherically symmetric distributions

Let X be a p-dimensional random vector with density f(6X?θ6) where θ is an unknown location vector. For p ≥ 3, conditions on f are given for which there exist minimax estimators θ?(X) satisfying 6Xt6 · 6θ?(X) ? X6 ≤ C, where C is a known constant depending on f. (The positive part estimator is among them.) The loss function is a nondecreasing concave function of 6θ?? θ6². If θ is assumed likely to lie in a ball in $\text{R}$^p, then minimax estimators are given which shrink from the observation X outside the ball in the direction of P(X) the closest point on the surface of the ball. The amount of shrinkage depends on the distance of X from the ball.     

Schur不等式的改进与特征值的估计

设复矩阵Ａ的特征值为λ１，…，λｎ．本文的目的，首先给出和的不等式用以改进Ｓｃｈｕｒ不等式，然后应用这些不等式去估计矩阵Ａ的特征值．