AVS中帧内预测模式的快速选择策略

为了降低AVS帧内预测模式的计算复杂度,提出了一种率失真优化（RDO）准则下的基于边缘特征的快速帧内预测模式选择算法。利用Sobel算子对亚采样后的图像建立边缘方向场,构建编码块的预测模式直方图,根据预测模式直方图的分布确定率失真优化候选预测模式;并对亮度块和色度块分别优化。仿真结果表明,与原AVS相比,该算法在比特率略有增加和信噪比基本保持不变的条件下,大大减少了计算时间,提高了AVS编码速度。     

自适应阈值AVS帧间模式快速选择算法

为降低AVS视频编码标准中帧间模式选择算法的复杂度,提出自适应阈值帧间模式快速选择算法。利用相邻宏块模式之间的相关性和预测模式统计分布规律预测当前宏块最可能预测模式,根据相邻宏块率失真代价的相关性自适应地调整判决阈值,如果帧间最可能预测模式率失真代价满足阈值判决准则,则最可能预测模式为最佳模式,提前退出模式搜索。实验结果表明,该算法在基本保持AVS原有编码性能的前提下编码速度得到较大提高。     

AVS中B帧宏块模式选择快速方法

为了降低AVS中B帧宏块模式选择的计算复杂度,提出了一种基于率失真优化（RDO）的宏块模式快速选择算法。根据人眼对图像边缘比较敏感的特点,提出了视觉阈值模型;利用sobel算子提取出宏块的边缘信息,并应用到视觉阈值模型中,从而得到了边缘点模型。在对图像水平、垂直纹理复杂度分析的基础上,对边缘点模型进行了选择,得到了宏块分割模式的快速算法;根据图像序列的时/空相关性提出了帧内预测判决算法。仿真结果表明,与原AVS全搜索算法相比,本算法在比特率略有增加和信噪比基本保持不变的条件下,使整个图像的总编码时间减少了40%左右,从而大大提高了AVS编码速度。     

H.264/AVC中基于决策树的P帧快速模式选择

目的 H.264/AVC帧间预测编码需要对所有可能编码模式计算并比较率失真代价,众多的模式类型导致了P帧编码的计算复杂度非常高。为此提出一种针对P帧的基于决策树的快速候选模式选择算法。方法在对宏块进行16×16的帧间运动估计后,首先根据残差宏块中4×4全零系数块个数对部分宏块直接选择出候选模式;然后使用16个4×4块的变换域系数绝对值之和(SATD)值,采用决策树分类方法对其余宏块选择候选模式。结果由于只需对候选模式进行编码,因此有效降低了编码器的计算复杂度。实验结果表明,与原始全搜索编码算法相比,该算法对不同运动程度的视频序列获得了较一致的编码时间的节省,同时平均峰值信噪比的损失和平均比特率的增加均较少。结论新的P帧帧间预测候选模式选择算法,根据帧间运动估计后的残差宏块信息,采用决策树方法对候选模式集进行分类。实验结果表明,该算法能在保证视频编码质量的前提下,有效地降低编码过程中的计算量,缩短编码时间。     

H.264帧内预测模式的快速选择算法

为了降低H.264标准中帧内预测模式选择的复杂度,提出一种快速的帧内预测方法.H.264采用率失真优化(RDO)算法,通过计算所有预测组合模式的率失真代价来确定宏块的最优编码模式,其计算复杂度非常大.提出的帧内预测快速选择方法利用宏块的绝对误差和(SAD)来缩小预测模式的范围,减少帧内预测的计算量,从而提高模式判别的速度.实验结果表明,在图像质量和码率基本保持不变的情况下,该算法使Ⅰ帧的编码速度提高约76%.     

H.264/AVC中基于决策树的P帧快速模式选择（HHME2013第61号论文）

目的：H.264/AVC帧间预测编码需要对所有可能编码模式计算并比较率失真代价,众多的模式类型导致了P帧编码的计算复杂度非常高。本文提出了一种针对P帧的基于决策树的快速选择候选模式算法。方法：在对宏块进行16×16的帧间运动估计后,首先根据残差宏块中4×4全零系数块个数对部分宏块直接选择出候选模式;然后使用16个4×4块的SATD值,采用决策树分类方法对其余宏块选择候选模式。结果：由于只需对候选模式进行编码,因此有效降低了编码器的计算复杂度。实验结果表明,与原始全搜索编码算法相比,该算法对不同运动程度的视频序列获得了较一致的编码时间节省,同时平均峰值信噪比的损失和平均比特率的增加均较少。结论：本文提出了一种新的P帧帧间预测候选模式选择算法,根据帧间运动估计后的残差宏块信息,采用决策树方法对候选模式集进行分类。实验结果表明,该算法能在保证视频编码质量的前提下,有效地降低编码过程中的计算量,缩短编码时间。     

基于SATD准则的HEVC快速帧内预测算法

相比于H.264/AVC视频编码标准,高效视频编码（HEVC）具有更大的压缩率和计算复杂度。HEVC更多的帧内预测模式显著地提升了编码器的率失真性能,但更高的算法复杂度使得编码时间大大增加。通过对典型序列编码的统计分析,提出一种基于变换残差绝对值和（SATD）的帧内预测模式快速选择算法,以降低HEVC帧内预测过程的计算复杂度。所提算法通过比较SATD来加速帧内预测模式的判决,避免了耗时的率失真代价（RD-Cost）计算,并且选择性地降低候选预测模式的数量,以减少总体编码时间。通过与现有其他HEVC快速算法进行比较测试,结果表明,所提算法平均减少了12.90%~19.89%的编码时间（编码器不进行任何优化）,而BD-Rate码率指标仅增加了0.5%~0.96%,几种算法的率失真性能基本一致。     

H.264/AVC高档次标准快速帧内模式选择算法研究

针对H.264/AVC高档次标准中帧内模式选择计算复杂度高的问题,提出一种新颖的基于纹理信息的快速帧内模式选择方法。利用绝对误差均值检测宏块的复杂度,选择块尺寸模式;利用平均绝对相邻像素差来检测图像块的纹理方向,筛选候选预测模式。实验结果表明,上述两部分算法单独使用都能够有效降低帧内模式选择的计算复杂度,使编码速度分别提高27%和64%,并且对率失真性能的影响可以忽略不计。利用整合后的综合算法,在率失真性能几乎保持不变的情况下,帧内编码速度提高超过70%以上。     

H.264帧内4×4块预测模式选择快速算法研究

在H.264视频编码过程中,编码时间受诸多因素的影响,如帧间/帧内模式选择、运动估计(ME)、率失真优化(RDO)等。为了以较快速度和较好质量进行编码,针对H.264帧内模式选择,提出了一种适用于H.264帧内4×4块预测的模式选择快速算法。该算法利用帧内4×4块最优预测模式与和它相邻的预测模式之间率失真代价(RD Cost)的高相关性,以及绝对变换误差和(SATD)与率失真(RD)性能之间的强相关性,有效地跳过一些不太可能的预测模式,从而使帧内4×4块模式选择过程只需进行4次率失真代价计算即可。实验结果显示,该算法在编码性能和编码速度之间取得了很好的折衷。     

基于AVS的帧内预测模式快速选择算法

AVS视频标准采用率失真优化（RDO）算法来提高帧内预测的压缩性能。但是RDO算法在保证编码图像获得最佳的压缩效率和图像质量的同时给整个编码过程带来了很大的计算量。提出了一种简单有效的AVS1-P2帧内预测模式的快速选择算法。该算法利用相邻块最佳预测模式之间的相关性和块内亮度变化的方向性来缩小候选模式的范围,从而有效节省了编码总时间。实验结果证明,与AVS1-P2的标准参考软件rm52j相比,本算法在保证图像质量和比特率几乎不变的情况下,编码总时间减少了24%~27%。     

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.