网络新闻传播失真原因探析

网络技术日渐成熟,网络新闻逐渐成为人们获取信息的主要途径。网络新闻以其便捷,快速,实时性强成为继报刊、电视之后的重要新闻报道形式之一。但是目前网络新闻的现状令人堪忧,部分网络新闻传播失真,片面追求轰动效应。新闻的真实性是新闻的核心要素,为规避新闻传播失真,社会各界应做出相应的措施来提高网络新闻可信度。

网络新闻传播中的失真原因剖析

信息技术的发展使得网络新闻得到了快速的发展与推广,这种快捷、方便的新闻传播方式受到了人们的普遍喜爱,成为人们获取信息的主要渠道,网络新闻在传播中具有更加显著的实时性特点,逐渐取代了报纸、电视等传统媒体传播的方式,但是网络新闻传播中的失真问题也是不容忽视的,在今后的发展中要结合实际情况提升网络新闻的真实度。

基于失真反向传播的时域依赖率失真优化

率失真优化是基于块的混合视频编码器中一项关键技术,然而广泛采用的独立率失真优化远未取得最优编码性能。为提升高效视频编码的率失真性能,提出了一种时域依赖率失真优化算法。首先,采用指数形式率失真函数,推导出时域失真传播因子的计算式;然后,通过预编码获得编码失真和运动补偿预测误差,并采用失真反向传播估算时域失真传播因子;最后,自适应地调节编码树单元的拉格朗日乘子和量化参数,以优化编码比特资源分配。实验结果显示,在低时延编码配置下,相比于高效视频编码的率失真优化算法,所提算法在获得同等重建视频质量的前提下,将所有测试视频码率平均节省4.4%,BasketballDrill序列码率最高节省13.0%。

视频编码失真估计综述

编码失真是评价视频算法性能的主要因素之一,如率失真优化、码率控制和最佳量化等算法设计中,在不进行复杂预编码的情况下精确估计编码失真,是达到良好率失真性能的必要途径。虽然部分编码失真估计方法已经被采用并作为编码算法的基础,然而,与对码率估计的关注度不同,失真估计并未引起人们的足够关注。系统地回顾总结了视频编码失真估计方法,实验并给出了一些比较结果。将失真估计方法分为四类:1)基于DCT系数分布的建模;2)ρ域;3)λ域和4)基于失真传播的建模。概述了这些方法的基本原理,并且根据实验结果对模型的精度进行了简要对比分析。

Attenuation and Distortion of Compression Waves Propagating in Very Long Tube

A lot of phenomena related to propagating various waves are seen when the high-speed train goes through the tunnel,the gas pipeline is broken due to an accident or the air brake of the wagon operates.For instance,a compression wave generated ahead of a high-speed train entering a tunnel propagates to the tunnel exit and spouts as a micro pressure wave,which causes an exploding sound.In order to estimate the magnitude correctly,the mechanism of the attenuation and distortion of a compression wave propagating along a very long tunnel must be understood and the experimental information on these phenomena is required.An experimental investigation is carried out to clarify the attenuation and distortion of the propagating compression wave in a very long tube.Experimental results show that the strength of a compression wave decreases with distance.The attenuation and distortion of compression waves are affected by the initial waveform of the compression wave and by the unsteady boundary layer induced by the propagating wave.The shape of a compression wave becomes different with the propagating distance;that is,a shock wave appears just head of a wavefront and an overshoot on pressure distribution is observed behind a shock wave due to the transition of the unsteady boundary layer.

Constraints on the Distortion of Area Objects in the Process of Map Objects Displacement

The displacement operator is an important and still a hot topic in map generalization. In the generalization product, symbols must be unambiguous and easily perceived and readily understood, which makes space competition among features an important obstacle in the process of map objects displacement. Space conflict between objects, through propagation process, may be spread and more objects may drift into it. In order to maintain symbols equilibrium and spatial relationship between objects, some unimportant symbols or parts of symbols should be distorted under constraints according to visual graphic resolution thresholds to figure out space competition among map features. Three constraints including position, legibility and characteristics are important for the maintenance of symbols equilibrium and spatial relationship, which are discussed in this paper. The skeleton is introduced to represent area objects figure characteristic, in which an area object can be separated to parts hierarchically according to their importance in the construction. Then, the finite element method is applied to the map objects’ displacement and distortion, in which a strategy for the parameters of finite element method is discussed.