关于逆Walsh序的快速Walsh变换算法研究

从Walsh变换算法出发，总结出快速算法中的二分技术设计思路，提出了逆Walsh序的快速Walsh变换算法，给出了逆Walsh序的算法的流程图，为算法在图像处理中的实际应用打下基础。     

Walsh矩阵的复制生成及其计算机图像

Walsh函数在信号处理、图像处理、通信等众多领域有着广泛的应用.Walsh函数系是一个正交而完备的函数系,可以通过多种方法生成这一函数系.其中,Swick提出的复制方法应用最为广泛,该方法以Walsh函数的序码作为复制信息,可以复制出任意给定序数的Walsh函数.其本质是基于向量的处理,不适于类似快速变换等二维信号的处理.Walsh函数系可用Walsh方阵Wk表示.提出了基于W_k的行复制和块复制方法.基于对称性引入复制算子,并发现了一种新序(类Walsh序).利用Kronecker积推导了6种序的Walsh方阵的递推公式并绘制了它们的计算机图像,发现这些图像具有分形意义上的自相似结构.结果表明,基于矩阵的复制是比基于序码的复制更先进的复制方法.前者性能更优,适于快速变换的设计.而且,利用它发现了Walsh函数系的第4种对称的序:类Walsh序.通过分析和比较各种序的计算机图像,得出类Walsh序更适合作为Walsh序的逆反形式的猜想.     

Walsh变换核矩阵的简单生成及其应用

本文讨论了Walsh函数的Walsh序、Paley序与Hadamard序相应的变换核矩阵的相互转化关系，给出了三类序的Walsh变换核矩阵的生成算法，且生成算法简单，还给出了Matlab生成该类矩阵的Matlab程序，并将几类矩阵的转换置换矩阵应用到图像信息的加密置乱中，置乱效果很好。     

一维Walsh变换的阵列协处理器的设计

本文给出了一种用短序列Walsh变换芯片构成长序列Walsh变换阵列协处理器的方法.按此法,易用2~t片2~t长芯片构成2~(2t)长的Walsh变换的阵列协处理器,并且易用2~(t+1)片2~t长芯片及2~(2t)个蝶形运算器构成2~(2t+1)长的Walsh变换的阵列协处理器.     

一种基于Walsh变换的立体匹配基元

提出了一种以Walsh变换系数作为匹配基元的双目立体匹配方法。通过Walsh正交变换核对图像，变换得到Walsh系数，图像的特征被嵌入到该系数中，费用函数采用了Walsh变换系数作为匹配基元，而不是采用传统的像素灰度值。该文给出了算法的费用函数、匹配过程中相关的数据和最后的视差图。试验结果表明，将Walsh 系数作为一种匹配基元的方法是可行和有效的。     

多维离散Walsh变换快速算法设计

在分析二维离散Walsh变换形式化描述的基础上，以二维Walsh变换为例设计了一类多维离散型walsh变换的快速算法，分析了该算法的性能，指出这类算法形式多样，应用广泛。     

基于Walsh谱统计分布特征的水下入侵目标分类

提出一种利用目标回波Walsh统计分布特征识别水下入侵目标方法,文中探讨水下入侵目标回波的Walsh谱统计分布特征,提取其统计分布特征量,均值、标准差、偏度系数、峰度系数和波动系数构建特征空间,降低了直接用Walsh谱识别的特征维数。针对采集对应三种入侵目标的回波信号提取其Walsh谱统计分布特征量并进行分类识别实验,并给出了BP神经网络的分类结果。     

基于混沌和Walsh变换的二值图像加密算法

提出一种基于混沌映射和Walsh变换的二值图像加密算法。首先对二值图像进行混沌加密,再对混沌加密后的图像用Walsh变换进行置乱,实现图像信息的高强度加密。运用Walsh变换可以在很大程度上节约计算时间。仿真实验结果表明,混沌序列与Walsh变换相结合的方法加密强度高,计算时间短。     

基于Walsh变换的数字水印算法*

经对目前数字水印变换域算法的研究,发现常用的变换大多都是正交变换（如DCT和DWT等）。通过对Walsh正交函数系的研究,获得了与之对应的性能优良的正交变换,提出一种新颖的、鲁棒的Walsh域盲水印算法。实验表明,该算法计算简单,且具有良好的不可见性,并且在抵抗噪声和JPEG压缩攻击等方面具有较强的鲁棒性。     

时变线性系统最优控制的Walsh级数分析法

本文应用Walsh级数把最优控制问题转化成了一般代数极值问题,算法简洁明了,适合 计算机求解,并解决了以前用Walsh级数分析时一直难以处理的末端条件问题[1],同时给出 了计算实例,结果令人满意.     

Detecting and removing specularities in facial images

Specularities often confound algorithms designed to solve computer vision tasks such as image segmentation, object detection, and tracking. These tasks usually require color image segmentation to partition an image into regions, where each region corresponds to a particular material. Due to discontinuities resulting from shadows and specularities, a single material is often segmented into several sub-regions. In this paper, a specularity detection and removal technique is proposed that requires no camera calibration or other a priori information regarding the scene. The approach specifically addresses detecting and removing specularities in facial images. The image is first processed by the Luminance Multi-Scale Retinex [B.V. Funt, K. Barnard, M. Brockington, V. Cardei, Luminance-Based Multi-Scale Retinex, AIC’97, Kyoto, Japan, May 1997]. Second, potential specularities are detected and a wavefront is generated outwards from the peak of the specularity to its boundary or until a material boundary has been reached. Upon attaining the specularity boundary, the wavefront contracts inwards while coloring in the specularity until the latter no longer exists. The third step is discussed in a companion paper [M.D. Levine, J. Bhattacharyya, Removing shadows, Pattern Recognition Letters, 26 (2005) 251–265] where a method for detecting and removing shadows has also been introduced. The approach involves training Support Vector Machines to identify shadow boundaries based on their boundary properties. The latter are used to identify shadowed regions in the image and then assign to them the color of non-shadow neighbors of the same material as the shadow. Based on these three steps, we show that more meaningful color image segmentations can be achieved by compensating for illumination using the Illumination Compensation Method proposed in this paper. It is also demonstrated that the accuracy of facial skin detection improves significantly when this illumination compensation approach is used. Finally, we show how illumination compensation can increase the accuracy of face recognition.     

Biomechanical analysis of materials handling manipulators in short distance transfers of moderate mass objects: joint strength,spine forces and muscular antagonism

Although often suggested as a control measure to alleviate musculoskeletal stresses, the use of mechanical assistance devices (i.e. manipulators) in load transfers has not been extensively studied. Without data describing the biomechanical effects of such devices, justification for decisions regarding implementation of such tools is difficult. An experimental study of two types of mechanical manipulators (articulated arm and overhead hoist) was conducted to determine whether biomechanical stresses, and hence injury risk, would be alleviated. Short distance transfers of loads with moderate mass were performed both manually and with manipulator assistance under a variety of task conditions. Using analysis and output from new dynamic torso models, strength demands at the shoulders and low back, lumbar spine forces, and lumbar muscle antagonism were determined. Strength requirements decreased significantly at both the shoulders and low back when using either manipulator in comparison with similar transfers performed manually. Peak spine compression and anteriorposterior (a-p) shear forces were reduced by about 40% on average, and these reductions were shown to be primarily caused by decreases in hand forces and resultant spinal moments. Two metrics of muscular antagonism were defined, and analysis showed that torso muscle antagonism was largest overall when using the hoist. The results overall suggest that hoist-assisted transfers, although better in reducing spine compression forces, may impose relatively higher demands on coordination and/or stability at extreme heights or with torso twisting motions. The relatively higher strength requirements and spine compression associated with the articulated arm may be a result of the high inertia of the system. Potential benefits of practice and training are discussed, and conclusions regarding implementation of mechanical manipulators are given.     

A numerical model for the winter circulation in Lake Trichonis, Greece

Progress in the understanding and eventual management of lakes depends upon iterative interactions between model-guided measurements and measurement-tested model development. A research example of this progress can be demonstrated by the measurement campaigns that were mounted in Lake Trichonis, in central Greece. Numerical simulations and analytical theories have been tested against currents, surface seiche and temperatures. Simultaneous water gauges, current meters, anemometric stations, thermometers, sediment and water samplers were used for the verification of the model. The agreement between the theoretically predicted and experimentally determined data was satisfactory for most of the verifications. The most significant error was due to atmospheric pressure. The computed surface seiche showed excellent agreement with the observations, even in spectral analysis. The computed currents showed circulation patterns very similar to those measured in the field. The computed temperature distributions throughout the lake were not in good agreement because of incoming water from the bottom.     

基于属性优先关系的多用户Skyline查询处理算法#br#

Skyline查询为多目标决策等问题提供了解决方案。每个用户对数据属性的优先关系的需求不同,传统算法无法有效解决多用户场景下的偏好Skyline查询。针对该问题,提出一种基于属性优先关系的多用户偏好Skyline查询算法--MUPS算法。该算法基于属性权重对原始Skyline结果集通过新的σ-支配方式进行剪枝;同时,通过交互动态修正属性的权重大小,使最终结果更符合用户群的真实偏好需求。最后,在模拟和真实数据上验证MUPS算法的有效性和良好的交互性能。     

Parallel Fiber Coding in the Cerebellum for Life-Long Learning

Continuous and real-time learning is a difficult problem in robotics. To learn efficiently, it is important to recognize the current situation and learn appropriately for that context. To be effective, this requires the integration of a large number of sensorimotor and cognitive signals. So far, few principles on how to perform this integration have been proposed. Another limitation is the difficulty to include the complete contextual information to avoid destructive interference while learning different tasks.We suggest that a vertebrate brain structure important for sensorimotor coordination, the cerebellum, may provide answers to these difficult problems. We investigate how learning in the input layer of the cerebellum may successfully encode contextual knowledge in a representation useful for coordination and life-long learning. We propose that a sparsely-distributed and statistically-independent representation provides a valid criterion for the self-organizing classification and integration of context signals. A biologically motivated unsupervised learning algorithm that approximate such a representation is derived from maximum likelihood. This representation is beneficial for learning in the cerebellum by simplifying the credit assignment problem between what must be learned and the relevant signals in the current context for learning it. Due to its statistical independence, this representation is also beneficial for life-long learning by reducing the destructive interference across tasks, while retaining the ability to generalize. The benefits of the learning algorithm are investigated in a spiking model that learns to generate predictive smooth pursuit eye movements to follow target trajectories.     

Query rewritings using views for XPath queries,framework, and methodologies

Query rewriting using views is a technique that allows a query to be answered efficiently by using pre-computed materialized views. It has many applications, such as data caching, query optimization, schema integration, etc. This issue has been studied extensively for relational databases and, as a result, the technology is maturing. For XML data, however, the work is inadequate. Recently, several frameworks have been proposed for query rewriting using views for XPath queries, with the requirement that a rewriting must be complete. In this paper, we study the problem of query rewriting using views for XPath queries without requiring that the rewriting be complete. This will increase its applicability since in many cases, complete rewritings using views do not exist. We give formal definitions for various concepts to formulate the problem, and then propose solutions. Our solutions are built under the framework for query containment. We look into the problem from both theoretic perspectives, and algorithmic approaches. Two methods to generate rewritings using views are proposed, with different characteristics in terms of generalities and efficiencies. The maximality properties of the rewritings generated by these methods are discussed.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

Constrained and SNR-Based Solutions for TV-Hilbert Space Image Denoising

We examine the general regularization model which is based on total-variation for the structural part and a Hilbert-space norm for the oscillatory part. This framework generalizes the Rudin-Osher-Fatemi and the Osher-Sole-Vese models and opens way for new denoising or decomposition methods with tunable norms, which are adapted to the nature of the noise or textures of the image. We give sufficient conditions and prove the convergence of an iterative numerical implementation, following Chambolle’s projection algorithm. In this paper we focus on the denoising problem. In order to provide an automatic solution, a systematic method for choosing the weight between the energies is imperative. The classical method for selecting the weight parameter according to the noise variance is reformulated in a Hilbert space sense. Moreover, we generalize a recent study of Gilboa-Sochen-Zeevi where the weight parameter is selected such that the denoised result is close to optimal, in the SNR sense. A broader definition of SNR, which is frequency weighted, is formulated in the context of inner products. A necessary condition for maximal SNR is provided. Lower and upper bounds on the SNR performance of the classical and optimal strategies are established, under quite general assumptions.     

第四代GIS软件研究

地理信息系统是国家空间数据基础设施建设的重要组成部分,对国民经济建设和国家安全有着重要的意义,文中总结了GIS软件的发展历史与技术特点,结合IT技术的发展,指出了现有软件存在的不足,并分析了技术原因,根括了第四代GIS软件的研究目标和技术体系,提出了发展我国第四代GIS软件步骤的建议。