Rate-distortion optimized frame dropping and scheduling for multi-user conversational and streaming video

We propose a Rate-Distortion (RD) optimized strategy for frame-dropping and scheduling of multi-user conversa- tional and streaming videos. We consider a scenario where conversational and streaming videos share the forwarding resources at a network node. Two buffers are setup on the node to temporarily store the packets for these two types of video applications. For streaming video, a big buffer is used as the associated delay constraint of the application is moderate and a very small buffer is used for conversational video to ensure that the forwarding delay of every packet is limited. A scheduler is located behind these two buffers that dynamically assigns transmission slots on the outgoing link to the two buffers. Rate-distortion side information is used to perform RD-optimized frame dropping in case of node overload. Sharing the data rate on the outgoing link between the con- versational and the streaming videos is done either based on the fullness of the two associated buffers or on the mean incoming rates of the respective videos. Simulation results showed that our proposed RD-optimized frame dropping and scheduling ap- proach provides significant improvements in performance over the popular priority-based random dropping (PRD) technique.

Optimal source rate control for adapting VBR video over CBR channels

In this paper we discuss the source rate control problem of adapting variable bit-rate （VBR） compressed video over constant bit-rate （CBR） channels. Firstly we formulate it as an optimal control problem of a discrete linear system with state and control constraints. Then we apply the discrete maximum principle to get the optimal solution. Experimental results are given in the end. Compared with traditional algorithms, the proposed algorithm is suitable for the coder with continuous output rates, and can achieve the better solution. Our algorithm can be used in both off-line and on-line coding.

Dynamic Reconfigurable Structure with Rate Distortion Optimization

The Rate Distortion Optimization(RDO)algorithm in High Efficiency Video Coding(HEVC)has many iterations and a large number of calculations.In order to decrease the calculation time and meet the requirements of fast switching of RDO algorithms of different scales,an RDO dynamic reconfigurable structure is proposed.First,the Quantization Parameter(QP)and bit rate values were loaded through an H⁃tree Configurable Network(HCN),and the execution status of the array was detected in real time.When the switching request of the RDO algorithm was detected,the corresponding configuration information was delivered.This self⁃reconfiguration implementation method improved the flexibility and utilization of hardware.Experimental results show that when the control bit width was only increased by 31.25%,the designed configuration network could increase the number of controllable processing units by 32 times,and the execution cycle was 50%lower than the same type of design.Compared with previous RDO algorithm,the RDO algorithm implemented on the reconfigurable array based on the configuration network had an average operating frequency increase of 12.5%and an area reduction of 56.4%.

Efficient Rate Control Algorithm for Multi-view Video Coding

Rate control is one of the key factors influencing the multi-view video transmission.However,there is not a rate control algorithm in the existing Joint Multi-view Video Coding Model.In this paper,an efficient rate control algorithm and a bit allocation strategy for multi-view video coding are proposed.In order to obtain the consistent view quality,a bit allocation model based on the Lagrange optimum algorithm is firstly proposed.Secondly,considering the encoding statistical characteristics of different view types,a view weighting factor is introduced,and it will help improve the precision of bit allocation among views.Compared with the fixed QP control strategy,experiment results show that the proposed algorithm can efficiently control the bit rate and obtain more consistent views,with video visual quality improved.

Novel Rate-Control Algorithm Based on TM5 Framework

Rate control is a key technology in the fields of video coding and transmission, and it has attracted a great attention and has been studied extensively. The TM5 framework of MPEG-2 is a classical rate control algo-rithm and has being widely used. However, it has some underlying drawbacks during practical applications such as the poor rate control precision and high computational complexity. Hence, in this paper, a novel rate-control algorithm based on the TM5 framework is proposed. The drawback of the target bit allocation method of the original TM5 algorithm is firstly analyzed and improved. Then, a new rate-distortion model is incorporated into the rate control algorithm to implement rate prediction to enhance the rate-control precision. Meanwhile, the macro-block (MB) level rate control is adapted to be frame level to reduce the computational complexity. Experiments are conducted and some results are given. Compared with the original TM5 algo-rithm, the improved novel algorithm not only can enhance the rate-control precision but also can reduce the complexity and the fluctuation of decoded image quality.

An efficient rate control algorithm for JPEG2000 based on reverse order

The JPEG2000 image compression standard is the powerful encoder which can provide phenomenal rate-control performance. The post-compression rate-distortion(PCRD) algorithm in JPEG2000 is not efficient. It requires encoding all coding passes even though a large contribution of them will not be contained in the final code-stream. Tier-1 encoding in the JPEG2000 standard takes a significant amount of memory and coding time. In this work, a low-complexity rate distortion method for JPEG2000 is proposed. It is relied on a reverse order for the resolution levels and the coding passes. The proposed algorithm encodes only the coding passes contained in the final code-stream and it does not need any post compression rate control part. The computational complexity of proposed algorithm is negligible, making it suitable to compression and attaining a significant performance. Simulations results show that the proposed algorithm obtained the PSNR values are comparable with the optimal PCRD.

Efficient Rate Control for Motion JPEG2000 under Constraint Memory

Fine scalability can provide not only precise rate control for constant bitrate (CBR) traffic, but also accurate quality control for variable bitrate (VBR) traffic. Motion JPEG2000 is a codec that can provide fine scalability with bitstreams. An efficient rate control approach utilizing a single buffer and two kinds of threshold for Motion JPEG2000 under resource constraint was proposed, which can offer good result in the constant quality video.

Optimal control of natural resources in mining industry

The paper focuses on the optimal control of natural resources in mining industry. The purpose is to pro- pose an optimal extraction series of these resources during the lifetime of the Mine＇s maintenance. Fol- lowing the proposed optimal control model, a sensitivity analysis has been performed that includes the interest rate impact on the optimal solution. This study shows that the increasing of the interest rate sti- mulates faster extraction of the resources. The discounting factor induces that the resource has to be extracted faster hut this effect is counterbalanced by the diminishing returns of the annual cash flow. At higher parameters of ＂alpha＂ close to one of the power function about 80% from the whole resource will be extracted during the first 4 years of object/mine maintenance. An existence of unique positive root with respect to return of investment has been proposed and proved by two ways： by the ＂method of chords＂ and by using specialized software.

An Improved Rate Control Method Based on Modification at Scene Change for H.264

This paper presents an improved rate control method for H.264. First, the scene changes are detected by the average absolute difference of the brightness histograms between the adjacent frames. Then, the bit allocation and quantization parameters are adjusted, using a certain threshold. In addition, the calculation of the mean absolute difference （MAD） is modified in an alternative way, which makes the rate distortion optimization （RDO） more accurate. Extensive simulation results show that the proposed method, compared with G012, can improve the average peak signal-to-noise ratio （PSNR） and moderate the image quality.

Variable Bit Rate Fuzzy Control for Low Delay Video Coding

Rate control plays a critical role in achieving perceivable video quality under a variable bit rate,limited buffer sizes and low delay applications.Since a rate control system exhibits non-linear and unpredictable characteristics,it is difficult to establish a very accurate rate-distortion(R-D)model and acquire effective rate control performance.Considering the excellent control ability and low computing complexity of the fuzzy logic in non-linear systems,this paper proposes a bitrate control algorithm based on a fuzzy controller,named the Fuzzy Rate Control Algorithm(FRCA),for All-Intra(AI)and low-delay(LD)video source coding.Contributions of the proposed FRCA mainly consist of four aspects.First,fuzzy logic is adopted to minimize the deviation between the actual and the target buffer size in the hypothetical reference decoder(HRD).Second,a fast lookup table is employed in fuzzy rate control,which reduces computing cost of the control process.Third,an input domain determination scheme is proposed to improve the precision of the fuzzy controller.Fourth,a novel scene change detection is introduced and integrated in the FRCA to adaptively adjust the Group-of-Pictures(GOP)length when the source content fluctuates.The FRCA can be transplanted and implemented in various industry coders.Extensive experiments show that the FRCA has accurate variable bit-rate control ability and maintains a steady buffer size during the encoding processes.Compared with the default configuration encoding under AI and LD,the proposed FRCA can achieve the target bit rates more accurately in various classical encoders.

PRE-Processing for Video Coduing with Rate-Distortion Optimization Decision

This paper proposes an adaptive video pre-processing algorithm for video coding. This algorithm works on the original image before intraor inter-prediction. It adopts Gaussian filter to remove noise and insignificant features existing in images of video. Detection and restoration of edges are followed to restore the edges which are excessively filtered out in filtered images. Rate-Distortion Optimization （RDO） is employed to decide adaptively whether a processed block or a unprocessed block is coded into bit-streams doe more efficient coding. Our experiment results show that the algorithm achieves good coding performances on both subjective and objective aspects. In addition, the proposed pre-processing algorithm is transparent to decoder, and thus can be compliant with any video coding standards without modifying the decoder.

Improved rate-distortion optimized video coding using non-integer bit estimation and multiple Lambda search

Many modern video encoders use the Lagrangian rate-distortion optimization （RDO） algorithm for mode deci- sions during the compression procedure. For each encoding stage, this approach involves minimizing a cost, which is a function of rate, distortion and a multiplier called Lambda. This paper proposes to improve the RDO process by applying two modifications. The first modification is to increase the ac- curacy of rate estimation, which is achieved by computing a non-integer number of bits for arithmetic coding of the syntax elements. This leads to a more accurate cost computation and therefore a better mode decision. The second modification is to search and adjust the value of Lambda based on the char- acteristics of each coding stage. For the encoder used, this paper proposes to search multiple values of Lambda for the intra-4x4 mode decision. Moreover, a simple shift in Lambda value is proposed for motion estimation. Each of these modi- fications offers a certain gain in RDO performance, and, when all are combined, an average bit-rate saving of up to 7.0% can be achieved for the H.264/AVC codec while the same concept is applicable to the H.265/HEVC codec as well. The extra added complexity is contained to a certain level, and is also adjustable according to the processing resources available.

面向耕地保护的充填体-煤柱协同承载及地表沉陷控制研究

耕地是粮食安全的基石,而煤炭则是能源供应的保障。然而,采煤引起的耕地损毁问题在我国高潜水位平原煤粮复合区尤为显著。为了应对这一问题,提出基于充填体-煤柱协同承载体的区域性沉陷控制方法,以实现采煤效益与耕地保护之间的平衡。以河南省某矿区为例,基于面向耕地保护的区域性沉陷控制方法,首先,分析了充填体-煤柱协同承载体的形成过程及其设计原则;随后,使用PFC软件模拟了不同充实率对充填体-煤柱协同承载体稳定性的影响,并基于FLAC3D软件模拟确定了满足耕地保护指标的最优工作面开采参数。研究结果显示:充填体会对煤柱产生侧向支撑,有利于提高煤柱稳定性,形成共同支撑覆岩的协同承载体。当充实率达到85%时,充填区裂纹约占总数的73.42%,此时充填体在协同承载体中发挥主要承载作用,系统处于稳定状态。进一步分析表明,采空区位于应力释放区,而协同承载体位于应力集中区,其应力集中系数呈现出随采宽增大而上升的趋势。在综合考虑充填成本和耕地保护指标后,确定了该矿区最佳的区域性沉陷控制开采参数为采宽160 m、充填宽100 m。该参数设置既能够节约充填成本,又能有效控制地表下沉量,达到耕地保护的标准。该研究成果可为煤粮复合区的绿色开采提供理论依据和工程参考。

单重休假和可变失效率的N-策略可修排队分析与费用优化

本文研究在N-策略控制下有单重休假和可变失效率的M/G/1可修排队系统,其中每当系统清空顾客,服务员就立刻开启一次不中断休假。当服务员休假回来若发现系统中至少有N个顾客时便立即开始服务,否则便待在系统中直到有N个顾客再提供服务,而且服务台在其忙期和闲期中的失效率不同。首先应用稳态队长的随机分解性质推导出了稳态队长的概率母函数,然后通过一些代数运算得到了系统一些排队性能指标,如平均队长、忙循环的平均长度和顾客的平均等待时间等。其次,我们还得到了服务台的可靠性指标,如不可用度和故障频度。最后建立费用目标函数,用数值实例讨论了有(没有)等待时间约束下的费用优化问题,并得到了使得费用最小的一维最优控制策略N*和当休假时间长度固定为T时的二维最优控制策略(N*,T*)。

基于PSO-BP神经网络的回转窑喷煤量预测

喷煤量调节是回转窑内各段温度控制的主要途径和手段,但由于回转窑内球团的煅烧过程具有非线性、时滞性、多变量和不确定性等特点,该部分温度难以有效控制。本文构建一种基于粒子群算法优化BP神经网络(PSO-BP)的回转窑喷煤量预测模型,通过仿真试验对比喷煤量的预测值与实际值,分析误差和辨识模型的拟合效果。结果表明:PSO-BP神经网络预测模型的精度优于原始BP神经网络,具有较高的寻优效率,总体拟合效果较好,其线性拟合度约为0.95,绝对误差约为0.09 t/h,相对误差约为2.4%。基于PSO-BP神经网络模型预测预热段的温度平均相对误差为0.8%,总体平均温度波动在±10℃以内,说明构建的回转窑喷煤量预测模型准确可靠且适用性强,将建立的神经网络作为前馈控制模块与传统的PID控制相结合构成预热段温度自动控制系统,可实现回转窑温度场稳定控制。

面向H.266/VVC的R-λ帧内码率控制算法

在R-λ帧内码控中,提出基于卷积神经网络(Convolutional Neural Networks,CNN)的最佳比特分配和最优拉格朗日因子λ选择。首先,探索编码树单元(Coding Tree Unit,CTU)的码率与失真(Rate-Distortion,R-D)及码率与拉格朗日因子λ(Rate-λ,R-λ)的关系特性,设计具有四输出的CNN预测R-D和R-λ曲线的关键参数;然后,建立帧级λ和目标码率的优化方程,反演得到最佳CTU码率分配;最后,根据CTU码率分配和先知的R-λ曲线,得到最优CTU级λ。实验表明,算法在保持4.76%控制精度下,比VTM13.0默认码控算法提高0.31 dB的编码质量。

Optimized beaconing rate control for vehicular Ad-hoc networks

In vehicular Ad-hoc networks （VANETs）, beacon message is designed for the purpose of periodically broadcasting the status information （velocity, direction, etc.）, which enable neighbor awareness and support some safety applications. However, under high density scenarios, fixed rate beaconing can cause severe congestion and lower the deliver rate of beacons and other kinds of messages. In this paper, we describe beaconing rate control approach with an one-dimensional Markov model, and based on this, an optimized beacon rate control scheme is proposed which aims to mitigate the congestion and maximize the deliver efficiency of beaconing. Analytical and simulation results show that our proposed scheme can achieve higher adaptability and beaconing efficiency compared with other schemes in various environments.

Optimal decay rate of vibrating beam equations controlled by combined boundary feedback forces

The optimal decay rate problem is considered for boundary control system modeling by a flexible structure consisting of a Eular-Bernoulli beam. Controls are a bending moment in proportion to angular velocity and a shear force in proportion to velocity. A sensitivity asymptotic analysis of the system's eigenvalues and eigenfunctions is set up. It is proved that, for every 0<K 2<+∞ and 0<-K 1<+∞, all the generalized eigenfunctions of form a Riesz basis ofV×H, and the optimal exponential decay rate can be obtained from the spectrum of the system.

产业结构与环境污染关系的实证分析——基于1995-2009年的数据

本文首先运用Granger因果检验方法分析国民经济各产业产出与污染排放量之间的联系;然后用回归方法分析三大产业在国民经济中所占的比例变化对环境污染的影响;之后针对各地区不同工业内部格局,计算相应的污染治理努力程度。研究表明:环境污染与各产业产值间存在长期稳定的协同效应;三大产业在国民经济中所占的比例影响着环境污染,工业产业是污染排放的最大因素;污染控制总量不能直接评价一个地区污染治理努力程度。

MPEG-4视频的实时传输

ＭＰＥＧ－４是一个全新的多媒体标准，采用了基于对象和模型的编码方法。简要总结了 ＭＰＥＧ－４视频编码的各种特点，对网络实时传输ＭＰＥＧ－４视频提出了各种评估标准。