Zk线性码的对称形式的MacWilliams恒等式

该文定义了Zk线性码的码字的对称重量计数公式，利用离散的Hadamard变换，建立了线性码与其对偶码之间的对称形式的MacWilliams恒等式．     

连续小波变换在多元函数空问中的应用

使用连续小波变换讨论了某些偏微分方程和相应的积分方程之间的关系．使用连续小波变换能够将这些偏微分方程变换成相应的积分方程，这些偏微分方程与相应的积分方程不仅在弱收敛意义下是等价的，而且在范数收敛意义下也是等价的．     

Singular Trajectories in Multi-Input Time-Optimal Problems: Application to Controlled Mechanical Systems

This paper deals with the time-optimal control problem for a class of control systems which includes controlled mechanical systems with possible dissipation terms. The Lie algebras associated with such mechanical systems have certain special properties. These properties are explored and used in conjunction with the Pontryagin maximum principle to determine the structure of singular extremals and, in particular, time-optimal trajectories. The theory is illustrated by an application to a time-optimal problem for a class of underwater vehicles.     

Efficient use of route requests for loop-free on-demand routing in ad hoc networks

On-demand routing protocols flood a route request (RREQ) identified by a unique source-sequenced label (SSL) to build directed acyclic graphs (DAG) consisting of possible paths to destinations, and use reverse paths along such DAGs to send route replies from the destinations. We present the first framework that uses only the SSL of the RREQ to establish loop-free paths without requiring additional mechanisms or information, e.g., per destination-sequence numbers or source routing. We present the Labeled Successor Routing (LSR) protocol, which stores the SSL of the RREQ as a route request label (RRL) at the nodes that participated in the creation of the RREQ DAG. The RRLs allow the source of the RREQ to identify neighbors as loop-free successors to the destination, which reduces network-wide RREQ flooding. Simulations results for scenarios consisting of networks of 50 and 100 mobile nodes show that LSR performs comparably or better than the Dynamic Source Routing (DSR) protocol, the Ad hoc On-demand Distance Vector (AODV) routing protocol, and the Optimized Link State Routing (OLSR) protocol.     

Probabilistic linear models for multiresolution estimation in gray-level images

A multiresolution analysis of digital gray-level images is presented. A gray-level multi-scale framework is determined from two main assumptions: the gray scale is binary at the finest spatial resolution, and the gray levels of composed regions are obtained additively. In order to interrelate the gray-level histograms of the same image at different resolutions, probabilistic linear models are developed, which are then applied for estimation. Linear-optimization theory is used as a way of constructing such models. A general procedure for image processing is sketched, based on gray-level estimation. A versatile algorithm for nonlinear filtering is derived. Some examples of prospective applications are given.This work was partially supported by grant TIC91-646 from the DGYCIT of the Spanish Government.     

Fluid flow and heat transfer in an optical fiber coating process

The optical fiber coating process, using a die and applicator system, was numerically simulated. The coupled partial differential equations, governing the fluid flow and heat transfer, were solved on a transformed, non-uniform, staggered grid. A finite volume method, with conjugate heat transfer, boundary-fitted grid, and variable transport properties, was employed. The pressure was calculated using a SIMPLE-based algorithm. An isothermal case was first modeled, where the effect of the Reynolds number (Re) was studied for different geometries. Different coating fluids were considered. A conjugate boundary condition was employed at the fiber–fluid interface for the non-isothermal flow. A free surface boundary condition was used at the fiber entry into the coating fluid. The meniscus was prescribed on the basis of prior experimental work. Regardless of fiber speed, a circulating flow was observed in the applicator. High shear rates at the dynamic contact point suggest that air can be entrained with a fast moving fiber. It was also found that pressures at the coating fluid inlet did not play a major role, for typical fiber speeds, whereas the thermal conditions that affect the properties of the fluid, such as viscosity, made a significant impact on both the flow and the thermal field. This work could be used to determine the parameters that are critical for improving the quality of the coating, particularly its uniformity, and the production rate.     

基于分水岭和区域合并的图像分割算法*

提出一种应用分水岭与区域合并相结合的图像分割算法.本方法首先利用数学形态学分水岭算法对图像进行分割,然后对分割后的图像进行相似区域合并,以减少分水岭方法产生的过分割现象,从而得到较好的分割效果.     

Equi-affine Invariant Geometry for Shape Analysis

Traditional models of bendable surfaces are based on the exact or approximate invariance to deformations that do not tear or stretch the shape, leaving intact an intrinsic geometry associated with it. These geometries are typically defined using either the shortest path length (geodesic distance), or properties of heat diffusion (diffusion distance) on the surface. Both measures are implicitly derived from the metric induced by the ambient Euclidean space. In this paper, we depart from this restrictive assumption by observing that a different choice of the metric results in a richer set of geometric invariants. We apply equi-affine geometry for analyzing arbitrary shapes with positive Gaussian curvature. The potential of the proposed framework is explored in a range of applications such as shape matching and retrieval, symmetry detection, and computation of Voroni tessellation. We show that in some shape analysis tasks, equi-affine-invariant intrinsic geometries often outperform their Euclidean-based counterparts. We further explore the potential of this metric in facial anthropometry of newborns. We show that intrinsic properties of this homogeneous group are better captured using the equi-affine metric.