H.264帧内预测与帧间块模式选择快速算法

针对H.264帧间预测时的多子块模式选择和帧内预测的多模式选择问题,提出了一种实用的基于统计门限的模式快速选择算法,通过门限设定有效限定了编码模式的选择范围.多组视频序列的实验结果表明,基于统计门限的帧内预测模式选择算法在Ⅰ帧的PSNR值有微小变化的情况下,大大降低了编码时间,Ⅰ帧的编码时间降低17%～23%,PSNR下降不到0.4%.基于统计门限的帧间块模式选择算法使得平均PSNR值下降了0.047dB(PSNR最大下降不到1%),但是相对全模式预测时,编码器速度提高了20%～30%.     

帧内预测模式快速选择方法研究

H．264标准中的帧内预测方法在很大程度上提高了帧内编码的效率,但同时也增加了编码复杂度。对其中运算量很大的预测模式选择策略和几种改进方法进行了分析,提出了一种自适应的快速预测模式选择方法。该方法主要基于最可能预测模式的自适应阈值和预测模式的选择计算。实验表明,该方法在基本保持了帧内压缩效率的同时,提高了编码的时间效率,而且能够较好支持SIMD指令,有利于汇编指令优化。     

H.264帧间预测模式选择算法研究与优化

H.264出色的压缩性能是以计算复杂度的提高为代价的。使用快速帧间预测模式选择算法是提高H.264编码速率的一种有效方法。文中对H.264帧间预测模式选择的复杂度进行分析之后，对基于X264参考程序的帧间预测算法提出改进，测试结果显示这种改进能将H．264的编码速率提高55％左右。     

一种新的面向隔行视频的AVS帧内预测模式

详细介绍了AVS1-P2中的帧内预测和MBAFF技术,提出了一种新的帧内预测模式.通过分析其中的5种亮度帧内预测模式和新帧内预测模式的相关性利用度,证明该模式很好地利用了隔行视频像素的空间分布特点,与原有的预测模式相比,更好地去除了图像块之间的空间相关性.实验表明该模式可以在标清、高清隔行视频的帧内预测上获得平均0.12dB以上的信噪比增益,平均减少1.77%的码流,是一种有效提高编码效率的预测模式.     

AVS视频编码标准的帧间预测算法研究

介绍AVS视频编码标准的帧间预测技术特点,对帧间预测算法进行分析和研究,为视频帧间编码提供理论依据。     

H.264编码模式选择的研究

研究H.264的编码模式选择方案,根据视频序列的时域相关性和空域相关性的关系,模式选择包括帧内预测和帧间预测,帧间预测基于率失真函数,在一帧图像的编码中则可以采用提前终止预测方向的方法降低编码器端的复杂度.     

基于编码模式的H.264/AVC视频信息隐藏算法

本文提出一种基于编码模式的H.264/AVC信息隐藏方法,通过调制某些宏块的编码模式,分别在Ⅰ帧、P帧和B帧中嵌入隐秘信息.对帧内4x4预测模式的宏块,是通过调整宏块中某个4×4块的编码模式嵌入隐秘信息;对P帧和B帧其它类型的宏块,则是通过调整宏块的编码模式嵌入隐秘信息,模式调整后对宏块做了优化处理.在模式调制过程中引入率失真代价,取得了较好的率失真平衡,减小了隐秘信息嵌入后对视频质量和视频码流的影响.该算法可以实现隐秘信息的快速提取,满足视频实时处理的要求,实验仿真结果证明了该算法的有效性.     

动背景下帧差分法与边缘信息融合的目标检测算法

针对动背景下运动目标的检测问题,文中提出了改进的三步搜索算法有效地提高灰度投影法检测序列帧间运动矢量搜索速度,同时保持了运动矢量的搜索精度.首先通过帧间运动矢量补偿将连续三帧图像的相同背景稳定在同一幅图像的相同位置上,其次对连续的三帧图像进行边缘信息提取,并对三帧连续的边缘图像进行差分法运算,最后结合数学形态学的闭运算...     

基于帧间差分和运动估计的Camshift目标跟踪算法

针对Camshift算法无法适应目标的高速运动、复杂背景和遮挡的局限性,本文提出结合帧间差分法和运动估计对Camshift算法进行改进.首先在颜色概率分布图计算中通过帧间差分法加入目标运动信息,实现自动初始化跟踪并排除与目标相似背景颜色的干扰.之后在搜索窗传递过程中预测目标的位置,根据跟踪状态对搜索窗进行调整,以实现对高速运动目标的跟踪.实验表明新算法在目标高速运动、遮挡、和同色干扰情况下,仍能进行有效跟踪.     

一种基于预测模式的H.264/AVC视频信息隐藏改进算法

提出了一种基于帧内预测模式调制的H.264/AVC视频信息改进隐藏算法.选择参考像素亮度值接近的帧内4×4块,通过对预测模式值进行调制以实现隐秘信息的嵌入,而预测模式调制过程是将最优预测模式变为满足嵌入条件的具有率失真开销最小的预测模式,以尽量减小预测模式的改变对视频客观质量的影响.信息的提取过程不需要原始载体视频,也...     

Empirical best prediction under area-level Poisson mixed models

The paper studies the applicability of area-level Poisson mixed models to estimate small area counting indicators. Among the available procedures for fitting generalized linear models, the method of moments (MM) and the penalised quasi-likelihood (PQL) method are employed. The empirical best predictor (EBP) of the area mean is derived using MM and compared with plug-in alternatives using MM and PQL. The plug-in estimator using PQL is computationally faster and provides competitive performance with respect to EBP that involves high complex integrals. An approximation to the mean squared error (MSE) of the EBP is given and three MSE estimators are proposed. The first two MSE estimators are plug-in estimators without and with bias correction to the second order and the third one is based on parametric bootstrap. Several simulation experiments are carried out for analysing the behaviour of the EBP and for comparing the estimators of the MSE of the EBP. A good choice in practice is the bootstrap alternative since it performs similarly to the analytical versions and is computationally faster. The developed methodology and software are applied to data from the 2008 Spanish living condition survey. The target of the application is the estimation of poverty rates at province level.     

An exact algorithm for project scheduling with multiple modes

We consider an extension of the classical resource-constrained project scheduling problem (RCPSP), which covers discrete resource-resource and time-resource tradeoffs. As a result a project scheduler is permitted to identify several alternatives or modes of accomplishment for each activity of the project. The solution procedure to be presented is a considerable generalization of the branch-and-bound algorithm proposed by Demeulemeester and Herroelen, which is currently the most powerful method for optimally solving the RCPSP. More precisely, we extend their concept of delay alternatives by introducing mode alternatives. The basic enumeration scheme is enhanced by dominance rules which increase the performance of the algorithm. We then report on our computational results obtained from the comparison with the most rapid procedure reported in the literature.     

An evolutionary algorithm for a new multi-objective location-inventory model in a distribution network with transportation modes and third-party logistics providers

This paper proposes a multi-objective optimisation algorithm for solving the new multi-objective location-inventory problem (MOLIP) in a distribution centre (DC) network with the presence of different transportation modes and third-party logistics (3PL) providers. 3PL is an external company that performs all or part of a company’s logistics functions. In order to increase the efficiency and responsiveness in a supply chain, it is assumed that 3PL is responsible to manage inventory in DCs and deliver products to customers according to the provided plan. DCs are determined so as to simultaneously minimise three conflicting objectives; namely, total costs, earliness and tardiness, and deterioration rate. In this paper, a non-dominated sorting genetic algorithm (NSGA-II) is proposed to perform high-quality search using two-parallel neighbourhood search procedures for creating initial solutions. The potential of this algorithm is evaluated by its application to the numerical example. Then, the obtained results are analysed and compared with multi-objective simulated annealing (MOSA). It is concluded that this algorithm is capable of generating a set of alternative DCs considering the optimisation of multiple objectives, significantly improving the decision-making process involved in the distribution network design.     

Looking for the best modes helps solving the MRCPSP/max

The multi-mode resource-constrained project scheduling problem with minimum and maximum time lags MRCPSP/max is a very general project scheduling problem with multiple execution modes per activity, renewable and non-renewable resources and minimum and maximum time lags between activities. In this paper, we describe SA-EVA, an algorithm for the problem. SA-EVA first searches for the best mode for each activity, without considering renewable resources. In this phase a simulated annealing is applied. Once a mode vector has been chosen, the problem reduces to the RCPSP/max, which SA-EVA solves with EVA, an algorithm designed in Ballestín et al. [2009. An evolutionary algorithm for the resource-constrained project scheduling problem with minimum and maximum time-lags. Journal of Scheduling, 14 (4), online]. Computational results show that SA-EVA outperforms the state-of-the-art algorithms in medium and large instances.     

Fast intra prediction mode decision for H.264/AVC video coding

Abstract

Intra coding is used for reducing the spatial redundancy in video coding. H.264 supports several macroblocks of predictions for intra coding such as luma block four 16×16 modes, nine 4×4 modes and chroma block four modes, which significantly improve intra coding efficiency, but increase the encoding complexity. In order to select the best mode, we need to calculate the cost of the various modes. In this paper, a fast intra prediction mode decision for H.264/AVC video coding is proposed. Based on Laplacian, this intra prediction mode decision detects edges and selects the best mode for the block. This mode decision can shorten the time to reduce the encoding time. The experimental results show that the proposed algorithm achieves an encoding time saving of 70% on average.     

A new approach of fatigue life prediction for metallic materials under multiaxial loading

Based on experimental data found in literatures, four traditionally multiaxial fatigue life criteria are analyzed and verified. It is discovered that these conventional criteria cannot reflect well the combined effect both under tension and torsion loadings for some materials, such as 6082-T6 and AlCu4Mg1, due to lack of enough consideration about the influence of stress amplitude ratio and stress level on fatigue life even under proportional loading. In order to solve this problem, a new approach of fatigue life prediction, based on the equal-life curve, is proposed and it is composed of three parts: the multiaxial fatigue life surface, a new path-dependent factor for multiaxial high-cycle fatigue and a material parameter describing material sensitivity to non-proportional loading. Finally, the precision of the presented approach is systematically checked against the experimental data found in literatures for four different materials under proportional and non-proportional loadings.     

A new algorithm for estimating fatigue life under mean value of stress

This paper discusses two problems: allowing for mean value of torsional stress and the variability of material properties with out of‐parallel fatigue characteristics. The effect of normal mean stress and shear mean stress is modified by reduction coefficients, which, to a large extent, depend on the value of existing loads. These coefficients have been developed experimentally on the basis of an analysis of the findings from fatigue tests on 2017A‐T4 and 6082‐T6 aluminium alloys and S355 alloy steel. The methods of calculation, suggested in this paper, are applicable to the materials in elastic–plastic state. The suggested algorithm for estimating fatigue life for the combination of bending or tension and compression and torsion under shear stress is based on Kluger's stress criterion. The usability of the algorithm was verified by comparing the calculation results with the results of own experimental tests on 2017A‐T4 and 6082‐T6 aluminium alloys, which have been noted to indicate sensitivity to shear mean stress, and the tests found in the professional literature (tests on S355, 30CrNiMo8 and 30NCD16 steel and Ti‐6Al‐4 V titanium alloy). A comparative analysis of the calculation and experimental results proved that there is a satisfactory correlation between them.     

An improved algorithm for optimizing product mix under the theory of constraints

One of the most important decisions made in production systems is determining the product mix in such a way that maximum throughput would be obtained. Several algorithms to determine the product mix under the theory of constraints (TOC) have been developed. In this paper, the inefficiency of the traditional TOC algorithm in handling the multiple bottleneck problem is discussed through an example. Then, the latest algorithm and its disadvantages will be discussed and an improved algorithm, which is much more efficient and can reach the optimum solution with considerable speed, will be presented. Finally, the improved algorithm and the integer linear programming (ILP) method will be compared with each other through the example.     

An algorithm for the kinetics of tire pyrolysis under different heating rates

Tires exhibit different kinetic behaviors when pyrolyzed under different heating rates. A new algorithm has been developed to investigate pyrolysis behavior of scrap tires. The algorithm includes heat and mass transfer equations to account for the different extents of thermal lag as the tire is heated at different heating rates. The algorithm uses an iterative approach to fit model equations to experimental data to obtain quantitative values of kinetic parameters. These parameters describe the pyrolysis process well, with good agreement (r² > 0.96) between the model and experimental data when the model is applied to three different brands of automobile tires heated under five different heating rates in a pure nitrogen atmosphere. The model agrees with other researchers’ results that frequencies factors increased and time constants decreased with increasing heating rates. The model also shows the change in the behavior of individual tire components when the heating rates are increased above 30 K min⁻¹. This result indicates that heating rates, rather than temperature, can significantly affect pyrolysis reactions. This algorithm is simple in structure and yet accurate in describing tire pyrolysis under a wide range of heating rates (10–50 K min⁻¹). It improves our understanding of the tire pyrolysis process by showing the relationship between the heating rate and the many components in a tire that depolymerize as parallel reactions.