体绘制技术在医学可视化中的新发展

科学计算可视化体绘制算法能反映出体数据的内部信息，在医学，它已经从辅诊断发展成为辅助治疗的重要手段，体可视化技术是医学可视化的重要研究内容，其处理过程包括体数据的获取，模型的建立，数据的映射，绘制等操作，该文介绍了医学可视化中常使用的几种光照模型，针对基于图象空间和对象空间两种体绘制算法，介绍了它们的基本思想方法，并详细阐述了在近期的主要加速技术和提高图象质量方法的新进展，最后给出了实验数据和结论。     

三维医学图象可视化技术综述

概要地分析和评述了近年来三维医学图象可视化技术的发展,并主要从三维医学图象的分割标注、多模态医学图象的数据整合、体数据的绘制等3个角度对三维医学图象的可视化技术进行了分类综述,同时介绍了各种算法的原理和最新进展,由于医学图象可视化的目的是辅助医学了解生物内部组织的信息,因此除图象绘制技术外,组织及组织特性的精确自动分割标注技术,以及将不同图象模态提供的互补信息综合起来的匹配/融合技术外,都是医学图象可视化需要解决的重要问题,其中,多模态图象的可视化在三维医学图象可视化领域中最具有挑战性和发展前景。     

医学体数据三维可视化方法的分类与评价

医学图象三维可视化具有极大的医学研究和临床诊疗应用前景,是现代医学影象研究的重要领域。医学图象三维可视化方法通常分为表面绘制和体绘制,已有许多具体的算法提出,一些算法兼具表面绘制和体绘制的特点,归为混合绘制方法,该文概述了一些典型算法,并讨论了其特点及相互联系,同时对各类方法的应用场合及前景了分析和评价。     

三维体可视化若干问题研究

首先对可视化技术特别是三维可视化算法进行了分析和对比，并根据体数据的建模方法对算法进行了归类，并指出了目前三维可视化技术存在的问题，继而从基于小波的分辨率模型的体绘制算法和基于Cluster模型的并行体绘制算法这两个方面具体探讨了对三维体可视化算法进一步研究的思路，首次提出了参数化的光照模型和图像质量评价的数学模型等概念。     

交互式动态体绘制及其加速算法

体绘制三维成象法是一门新兴的3D采样数据场可视化技术，在医学成象和科学可视化领域有着极为广泛的应用，但由于3D数据量大，其使用往往受到巨大计算开销的限制，因此很多研究人员致力于静态体绘制加速算法的研究，并解决医学图象三维可视化中三维体数据显示速度与成象质量问题，因而提出了一种交互式动态体绘制算法，即从任意的视点距离和视线方向进行动态编制，并在分析其算法复杂度的基础上，提出一种新的加速算法，同时使得动态体绘制过程几乎达到实时的效果，经验证，这种算法比标准算法快4～5倍。     

基于GPU的实时光线投射算法

介绍了一种基于GPU（可编程图形处理单元）的快速实时光线投射算法。为满足大规模体数据集的绘制要求,利用当前GPU的新特性,直接将体数据作为纹理载入显存,采用预积分分类方法在GPU中对体数据进行重采样和分类,避免了计算机主内存与GPU纹理内存之间数据交换的瓶颈问题;利用硬件支持的三维纹理和片元着色器,实时计算每个体素的梯度,实现高质量的光照,保证高质量的图像绘制效果。实验结果表明该方法在医学三维数据场可视化中,能够实时、高效地生成高质量的交互式体可视化图像。     

医学体数据三维可视化技术

医学体数据的可视化是科学计算可视化的重要研究领域,其处理过程包括体数据的获取、模型的建立、数据的映射、绘制等操作。论文对医学体数据可视化的相关技术进行了综述,讨论了医学体数据的结构模型和表示方法,全面地分析了医学体数据可视化中各种算法和技术的特点,及相关的加速技术,探讨了目前医学体数据可视化存在的问题及发展趋势。     

基于图象的交互绘制和数据压缩

体数据的绘制速度是交互可视化的瓶颈。将基于图象的绘制方法和传统的体绘制方法相结合,提出了一个新的基于图象的快速图形图象绘制系统,大大提高了体数据交互可视化的速度。该方法首先用传统的体绘制方法得到一列采样图象,然后根据图象间象素的冗合性,通过Ｗａｒｐｉｎｇ变换压缩数据,由压缩后的数据Ｗａｒｐｉｎｇ生成任意视点的视图。为了进一步提高计算速度,给出了递推Ｗａｒｐｉｎｇ变换计算流程。     

医学图像可视化的视觉优化方法

由于受主观意识和经验等因素的影响,医学图像可视化中传递函数的选择和设置会直接影响医学图像可视化效果.为此,提出一种基于视觉优化的医学图像可视化方法.针对三维医学图像绘制,采用基于GPU加速的光线投射体绘制半自动化传递函数,解决了三维图像全局和焦点上下文的优化显示问题;针对二维图像呈现,借助直方图均衡化、图像融合和全变分模型3种图像增强算法,解决了二维医学图像噪声干扰、对比度模糊和边缘丢失等问题.通过与传统方法的实验对比,三维医学图像在绘制时间和绘制效果方面均有改善;引入图像质量评估指标峰值信噪比和平均结构相似性,验证了全变分模型在二维医学图像增强中的有效性.结合视觉优化方法设计开发了医学图像可视化交互系统,包含对医学数据的三维可视化和交互分析功能,有效地拓展算法的应用性.     

全局光照环境中的逆向绘制

提出一种恢复场景中所有物体的反射特性的方法.算法以一个全景图、场景的完整几何模型和光源信息为输入,结果是场景的一个完整反射模型.恢复是以逐步求精的方式进行的.先假定物体表面是漫反射面并生成一幅全景图,然后算法逐步迭代,比较绘制的全景图和原始全景图,如果有的物体的误差超过某个阈值,算法为他们选择更负责的反射模型.最后,场景中的每个物体有了一个合适的反射模型,可以在新的光照和视点条件下绘制,旧的物体可以从场景中移去,新的物体可以添加到场景中.对漫反射、各向同性反射和各向异性反射纹理面的纹理恢复也作了深入研究;高光和阴影的影响也能基本去除.     

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.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。