基于感兴趣区域的可伸缩性容错编码

为了在低带宽的条件下提高视频质量并获得更高的编码效率,提出一种基于感兴趣区域(ROI)实现可伸缩容错编码的方法.在编码时结合基于ROI对象的动态FMO,满足了编码效率和容错性能的折衷.同时,结合FMO特性实现对增强层的感兴趣区域的优先传输,提高了视频质量和码流的可伸缩性.实验结果表明,该方法对于带宽受限条件下的图像传输具有很好的差错鲁棒性,图像PSNR可以提高2.5 dB左右,能为图像感兴趣区域提供有效保护,提高图像质量.     

一种基于镜头描述的可伸缩视频码流提取方法

可伸缩视频码流提取使视频流能够适应不同带宽的网络带宽和不同处理能力的终端。提出一种基于镜头描述的视频码流提取框架,通过离线预处理获得原始视频镜头的描述,建立参考帧二叉树,基于码流分析和镜头描述实现可伸缩码流提取。实验表明该方法可以实现快速码流提取,在不损失编码效率的前提下保证视觉质量。     

一种基于SPIHT算法的感兴趣区域编码新方法

在研究JPEG2000中的感兴趣区域(ROI)编码算法优缺点的基础上,结合嵌入式编码理论和人眼视觉特性,利用等级树分集(SPIHT)编码算法的特性,提出了一种高效的ROI编码方法,压缩后的码流具有嵌入式特点,支持渐进传输.实验结果表明:尽管在低码率下,该算法整体峰值信噪比较低,但主观视觉效果明显好于SPIHT算法,结果令人满意.     

可伸缩视频编码的码率控制技术研究

可伸缩视频编码能生成空域、时域、质量可伸缩的视频码流,如何对其进行码率控制来生成最优的可伸缩性码流,对适应不同需求的终端十分重要.结合可伸缩视频编码码率控制的研究现状,描述了最新的研究进展,综述了码流控制的原理、经典算法,分析总结了可伸缩视频编码的关键技术及在可伸缩视频编码中的挑战.通过对增强层中各种码率控制算法的优缺点的分析,总结出增强层的时域可扩展和空域可扩展中码率控制的最优解决方案.最后对可伸缩编码中码率控制技术的发展趋势进行了展望.     

适于交通监控的内容自适应空间可伸缩视频编码算法

当前空间可伸缩编码很少考虑视频感兴趣区域ROI(Region of Interest)或视觉突出内容,从而不能更好地适应视觉重要内容在较低分辨率移动终端的显示。对此,提出一种适用于交通监控的内容自适应空间可伸缩视频编码算法。采用背景差法获取运动车辆并进行目标跟踪,一般情况下在交通监控中主导车辆(视觉上最突出的车辆)所在运动窗为ROI,将该ROI设定为裁剪窗口,并使用H.264/AVC可伸缩编码SVC(Scalable Video Coding)标准的扩展空间可伸缩方法 ESS(Extended Spatial Scalability)进行编码,同时在空间增强层使用跟踪准确度代替PSNR作为质量度量标准。实验表明,该算法与传统的下采样空间扩展算法相比,对低分辨率空间层解码下的视觉感知有较大的改善,而且在保证跟踪相对准确的前提下,码率可以节省约60%。     

基于PBBShift的ROI编码方法

为使观察者提早了解图像的大致情况,提出了基于部分背景位平面位移(PBBShift)的感兴趣区域(ROI)编码方法.该方法将背景(BG)位平面分为两部分,编码时下移剩余的BG位平面,解码时可优先传输ROI系数和重要的BG系数,然后传输剩余的BG系数.实验证明,该方法在低码率下,ROI和BG质量相差无几;在高码率下,ROI获得比BG更好的质量.改进的方法在带宽受限的网络中有很大的实用价值.     

MGS片层重要性分析及其应用*

基于中粒度质量可伸缩（medium grain scalable, MGS）编码在可伸缩编码（scalable video coding, SVC）应用中的广泛性,在分析了MGS编码结构特点和问题的基础上,利用DCT系数分布特性提出MGS片层数据重要性的估计方法实现对MGS编码各片层重要性的估计。在此重要性估计方法的前提基础上,将之应用于指导可伸缩编码中的码流提取和容错编码。实验测试结果表明,MGS片层数据重要性估计方法的准确性和应用有效性,保障了视频码流质量,提高了码流提取效率。     

基于MPEG-4的FGS视频压缩技术的研究

精细可伸缩性视频编码FGS(Fine Granular Scalable)是MPEG-4标准的视频化框架中的关键性的编码技术。FGS编码方法生成两个视频流：基本层码流和增强层码流。基本层码流是必须传输的，并且码率低；增强层码流则根据带宽的实际情况来决定传多少，甚至不传，这种分级性的编码方式和传输方式使视频流有较好的鲁棒性。     

一种适宜于传输的视频编码方案

可伸缩视频编码方案因其能够适应不同带宽的网络以及不同的终端,近年得到了极大的发展,本文介绍了可伸缩编码方案所用的关键技术-基于运动补偿的时域滤波器(MCTF)、空域可伸缩、SNR域可伸缩,并提出了一种新的码流组织与选取方案.     

基于宏块的渐进、精细可伸缩的视频编

渐进精细可伸缩(PFGS)的视频编码是面向Internet的视频流化应用中的一项重要技术,同MPEG-4标准中的精细可伸缩(FGS)的视频编码相比,PFGS视频编码具有更高的编码效率.然而,由于现有的PFGS方法以帧为单位来选择编码时的参考图像,因此该方法很难同时在编码效率和误差控制方面都取得好的效果.提出了一种灵活、高效的基于宏块的PFGS编码方法,并提出3种帧间(INTER)编码方式用于增强层宏块编码,其中的一个编码方式把原有的PFGS视频编码中的误差控制技术扩展到了宏块层.同时也提出了一个编码方式选择算法以确定每个增强层宏块的编码方式,由于该算法仅需用到时域预测信息,因此实现起来非常简单,并且性能稳定.实验结果表明,基于宏块的PFGS视频编码既能有效地消除低码率下的误差传递和累积,也能提高在其他码率下的编码效率.     

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     

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。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.