小波双三次高倍插值搜索算法的遥感图像重建

由于光学遥感成像的距离较远和CCD物理尺寸的限制,获得的图像分辨率都比较低。为了在保持原始图像信息的情况下,提高图像的空间分辨率,改善图像的峰值信噪比,在深入分析前期研究中提出的小波双三次插值搜索算法的基础上,建立了小波双三次高倍插值搜索算法。该算法可以根据需要重建出原始遥感图像的高倍高分辨率遥感图像。实验结果表明,新算法重建出原始图像的2×2倍高分辨率图像的细节信息和视觉效果最好,3×3倍和4×4倍次之,5×5倍较差,更高倍数的高分辨率重建图像不宜在实际应用中采用。     

自由场中采用短时信号分析法的声脉冲叠加法测量反射系数

本文叙述了在自由场有限尺寸平板样品的反射系数测量中降低测试频率的新方法。在声脉冲叠加法基础上引入了短时信号分析法和发射器瞬态抑制法,使平板有效测试频段比经典的声脉冲响应法向低频延伸一个倍频程。本文给出了在铝板反射系数测量中用短时信号分析的结果,在有效测试频段内与理论值相比,误差小于10％。     

An exact algorithm for a workforce allocation problem with application to an analysis of cross-training policies

The evaluation of workforce staffing and scheduling policies is of paramount importance for meeting the challenge of simultaneously providing good customer service and low operational costs. Policy studies are particularly critical in workforce environments plagued by staffing shortages. The cross-utilization of employees among different departments or work centers is a well-recognized staffing policy for coping with shortages. We revisit a non-linear assignment problem for allocating cross-trained workers so as to maximize overall utility, which is measured using a quadratic function of labor shortages. We develop a branch-and-bound algorithm that efficiently provides optimal solutions for problems of practical size. This algorithm is then used to conduct a computational investigation of cross-training policies. Among the most critical factors affecting utility improvement are the coefficient of variation for demand, worker absenteeism, the percentage of cross-trained workers and cross-training breadth. Several important interactions among these and other factors are also identified.     

An axisymmetric heat conduction model for a multi-material cylindrical system with application to analysis of carbon nanotube based composites

A model for axisymmetric steady-state heat conduction in a multi-material cylindrical system containing a thermal superconductor is presented. An analytical solution in terms of series involving Bessel functions is derived for the temperature distribution in the multi-material system. The model may be applied to analyze the thermal behaviors of carbon nanotube based composites. Some results are obtained for specific cases of the multi-material system.     

Discrete singular convolution and its application to the analysis of plates with internal supports. Part 1: Theory and algorithm

This paper presents a novel computational approach, the discrete singular convolution (DSC) algorithm, for analysing plate structures. The basic philosophy behind the DSC algorithm for the approximation of functions and their derivatives is studied. Approximations to the delta distribution are constructed as either bandlimited reproducing kernels or approximate reproducing kernels. Unified features of the DSC algorithm for solving differential equations are explored. It is demonstrated that different methods of implementation for the present algorithm, such as global, local, Galerkin, collocation, and finite difference, can be deduced from a single starting point. The use of the algorithm for the vibration analysis of plates with internal supports is discussed. Detailed formulation is given to the treatment of different plate boundary conditions, including simply supported, elastically supported and clamped edges. This work paves the way for applying the DSC approach in the following paper to plates with complex support conditions, which have not been fully addressed in the literature yet. Copyright © 2002 John Wiley & Sons, Ltd.