一种多进制小波变换DEM数据简化方法

通过对DEM数据的二维多进制小波变换系数特征的讨论，针对三维地理景观的动态、实时绘制问题，提出了一种基于多进制小波变换的数字高程模型数据压缩方法，给出了DEM数据多进制小波系数编码压缩算法及其算法实验结果。     

基于小波分析的DEM数据多分辨率表达研究

在研究三维地形的数字模型中,针对现有DEM数据的多分辨率模型构建中存在的问题,为提高精度,减少失真,结合DEM数据的特点,提出了一种简化的基于小波的DEM数据多分辨率表达算法,通过改变多分辨率分解时高频信号的获取方式,使得DEM数据的多分辨率重构可以以一种相对简单的方式进行,从而使得多分辨率模型的重构效率得到了较大的提高。分析了由于分块小波变换而带来的边界失真问题,并根据滤波器系数的长度不同,提出了相应的解决方法,经试验证明重构效果有较大的提升。     

基于DEM的数字流域河网编码方法研究

数字流域模型中基于二叉树理论的河网编码方法能够实现任意河段的直接定位和高效的拓扑运算.论文首先讨论了利用DEM提取河网的基本原理,然后根据二叉树二元编码规则完成数字流域的河网编码.     

基于小波的数字高程模型压缩方法

根据地理信息系统中数字高程模型（DEM）的特点，提出一种基于小波变换的DEM数据压缩方法．文中主要研究了小波滤波器的选取、最优标量量化器的设计等问题，并对DEM小波分解系数进行了深入的分析．同时，应用该方法对实验DEM数据进行测试．结果表明，该方法较其他方法更为有效，能够在取得大压缩比的同时，有较好的数据恢复质量．     

数字高程模型数据的信息伪装和信息隐藏技术

提出了一种结合信息伪装和隐藏技术来保护数字高程模型(digital elevation model,简称DEM)数据的方法,保证了DEM数据的安全传输和存储.设计了DEM数据极低比特率压缩方法,压缩数据隐藏在伪装数据中.应用带参数整数小波变换,提出可嵌入隐藏信息的小波系数集合生成方法.扩展了只针对图像的基于视觉系统(human visual system,简称HVS)小波域量化噪声的视觉权重(just noticeable distortion,简称JND)分析方法,使其适用于DEM数据,自适应地确定信息     

数字高程模型数据整数小波水印算法

提出了一种高效、安全的数字高程模型(digital elevation mode,简称DEM)数据小波水印算法,以解决DEM数据版权保护和限制非法使用的问题.在理论上,基于提升理论构造了一种包含自由变量t的紧支撑小波,选取参数t=1的9/7整数小波基,只需要整数加法和移位实现,运算量低,便于硬件实现.提出可嵌入水印的小波系数集生成方法,扩展了基于视觉系统(HVS)小波域量化噪声的视觉权重(JND)分析方法,使其适用于DEM数据,并能够自适应地确定水印嵌入的强度.该算法在保证地形形状和起伏特征的前提下,提高了水印的鲁棒性.应用Rabin方法生成的单向Hash函数,水印算法可以完全公开.     

小波变换在图象压缩中的应用

本文讨论了数字图象数据信息压缩的有关技术问题，文章首先简要介绍了传统的Ｈｕｆｆｍａｎ编码方法的然后提出利用正交小波变换对图象进行分解，结合Ｈｕｆｆｍａｎ编码法图象进行编码，压缩的技术。     

移动计算环境中曲线数据实时压缩方法

移动计算环境中存储、计算和通信等资源受限,为了解决在资源受限环境中实时压缩和解压缩海量曲线数据的问题,提出了基于整形小波变换和FFEP编码的压缩方法.将曲线坐标根据给定容限从浮点数转换为整数,计算其一阶差分后进行整形小波变换;为了加快编码解码速度,提出FFEP编码方案,根据数据的概率分别采用4位、5位、8位及变长码进行编码,对经小波变换后的高频部分有较好的编码效果.由于坐标类型转换、小波变换和FFEP编码主要采用整数位运算及加减法运算并且在原存储空间实现,因此该方法具有较小的时间和空间复杂度.实验结果表明,本文方法能够在当前流行的PDA上将等高线数据实时地压缩到10%以内.     

大规模多分辨率地形实时绘制算法研究

为解决海量地形数据无法实现直接、连续地实时绘制的问题,根据小波分析的特点,提出了基于小波分析的多分辨率地形模型生成算法.该算法利用小波分析对数字高程模型(DEM,digital elevation model)数据进行简化压缩,采用四叉树结构来表示地形,构建视点相关多分辨率地形模型.实验结果表明,该算法使需要的地形数据量大为减少,能高效地生成地形的多分辨率模型,并且地形的逼真程度高.因此,该算法结构简单、便于实现大规模地形实时绘制.     

基于SPIHT编码的语音信号压缩算法

提出了一种基于最佳小波包变换和SPIHT编码的语音信号压缩编码方法。该方法首先对语音信号进行小波包变换,求解最佳小波树,进行动态位分配,再用改进的SPIHT算法对变换后的小波系数进行压缩编码。并且采用了熵编码的方法进一步提高了压缩比。实验表明,该方法在较高的压缩比下能获得较好的信号重构质量,计算复杂度低,延迟小。     

Assessing Ideational and Evaluative Skills and Creative Styles and Attitudes

This article describes the rationale for the multiphase creative problem solving process, and reports the findings from an empirical investigation conducted to facilitate the problem solving of managers. The ideational skills of the managers were assessed before and after training in a complete process of creative problem solving, along with their ideational attitudes, creative problem solving style (i.e., generator, conceptualizer, optimizer, or implementor), and evaluative skill (i.e., ability to recognize original ideas). The most important findings indicated that the training had a significant impact on the evaluative accuracy of the managers. They were significantly more accurate in their judgments about original ideas after training, both in their identification of original ideas and their recognition of unoriginal ideas. After training, the managers also gave more solutions and more original solutions to problems. Finally, several variables (e.g., the “preference for active divergence” attitude, and the conceptualizer process style) seemed to moderate the impact of training. Training was therefore effective, with specific effects that can be predicted from pre-training individual differences in attitudes and process style.     

Rank and select revisited and extended

The deep connection between the Burrows–Wheeler transform (BWT) and the so-called rank and select data structures for symbol sequences is the basis of most successful approaches to compressed text indexing. Rank of a symbol at a given position equals the number of times the symbol appears in the corresponding prefix of the sequence. Select is the inverse, retrieving the positions of the symbol occurrences. It has been shown that improvements to rank/select algorithms, in combination with the BWT, turn into improved compressed text indexes.     

Semantics and verification of monitors and systems of monitors and processes

In this paper we present a sound and complete semantics for the monitor concept of C.A.R. Hoare. First a method for specification of monitors, introduced by O.-J. Dahl, is reviewed. This method is based on the relation between the historic sequence of monitor procedure calls and the historic sequence of monitor procedure exits. Based on such specifications and our new monitor semantics we present a method by which it is possible to prove that a concrete monitor is an implementation of an abstract one. In the last part of the paper an axiomatic semantics for systems of concurrent processes and monitors is introduced. The method supports verification by separation of concerns: Properties of the communication to and from each process are proven in isolation by a usual Hoare style axiomatic semantics, while abstract monitors are also specified in isolation by the method reviewed in the first part of the paper. These properties of the components of the system are then used in a new proof rule to conclude properties of the complete system. Stein Gjessing received a Ph.D. (actually a Dr. philos.) from the University of Oslo (Norway) in 1985. Presently he is an Associate Professor at the Institute of informatics, University of Oslo, Norway. Dr. Gjessings research interests are in the area of concurrent and distributed programming, operating systems, formal specification and verification and programming languages.     

Integrating and automating analysis and optimization

The development of an interface coupling program on personal computers for an analysis software system such as ANSYS, SAP, etc. and an optimization software system, MOST, is presented. By controlling and directing the communications the interface coupler integrates the two programs while retaining their versatility and interactive features. The integrated system is used to solve a numerical example of active noise control for a three-dimensional enclosure, in which an energy density level of control points is minimized by adding the sound source to cancel the unwanted noise. The interface coupling program automates with relatively low cost the iterative process for designing an engineering system, remaining flexible in acoustical modelling and efficient in equation solving. Also, the coupling interface is developed in a general-purpose way so that it can be expanded easily to integrate more analysis software packages of different kinds.