A Study on Mutually Compensatory Property of Multimedia QoS

本研究的重点是IP网络上的音视频传输。研究结果可以分为以下五类：1。我们通过对以往基于QoS映射的用户级QoS评估研究进行了综述，发现了该技术领域存在的开放性问题，并找到了研究方向。作为用户级QoS的初步研究之一，在三类网络中对应用级QoS进行了评估。我们在ieee802的DiffServ网络上用AF服务处理了Web访问和流媒体服务的应用级QoS。1 .无线局域网，以及蓝牙网络中分段不匹配对QoS的影响。作为第二项初步研究，我们评估了音视频多播中目的地间的同步质量。比较了三种目标间同步方案在Tier模型的分层网络和无线自组织网络中的质量。对用户级QoS进行了区间尺度的评价。本文首先提出了一种利用配对比较法和比较判断法两种心理测量方法获得区间量表用户级QoS参数的方案。接下来，我们研究了端到端延迟的均值和标准差对实时音视频传输的用户级QoS的影响。我们还研究了用户级QoS的连续时间评估及其连续时间映射。研究了音视频传输中QoS的互补性。我们首先使用有序尺度MOS（Mean Opinion Score）作为用户级QoS参数来研究该属性。然后构造了区间尺度的用户级QoS参数，通过主成分分析和多元回归分析得到了应用级和用户级之间的QoS映射关系。此外，我们还考察了内容对互补性的影响。

This research focuses on audio-video transmission over IP networks. The research results can be classified into the following five categories.1.We have surveyed previous studies on user-level QoS assessment by means of QoS mapping, identified open problems in this technical area and found research directions for them.2.Assessment of application-level QoS has beenmade in three types of networks as one of preliminary studies on user-level QoS. We have treated application-level QoS of Web access and streaming services with AF service on DiffServ networks, that of IEEE 802. 1le wireless LANs, and the effect of segmentation mismatch on the QoS in Bluetooth networks.3.As the second preliminary study, we have assessed inter-destination synchronization quality in audio-video multicasting. The quality of three inter-destination synchronization schemes has been compared in a hierarchical network of a Tier model and in wireless ad hoc networks.4.User-level QoS has been evaluated in terms of the interval scale. We first proposed a scheme for obtaining a user-level QoS parameter of the interval scale by means of two psychometric methods : the methods of paired comparison and the law of comparative judgment. We next examined the effect of the mean and standard deviation of end-to-end delay on user-level QoS of live audio-video transmission. We also studied continuous time assessment of user-level QoS and its continuous time mapping.5.The mutually compensatory property of QoS has been investigated in audio-video transmission. We first studied the property using MOS(Mean Opinion Score), which is an ordinal scale, as the user-level QoS parameter. We then constructed a user-level QoS parameter of the interval scale and obtained QoS mapping relations between application-level and user-level by the principal component analysis and multiple regression analysis. Furthermore, we examined the effect of contents on the mutually compensatory property.