The object-based scalable coding in MPEG-4 is investigated, and a prioritized transmission scheme of MPEG-4 audio-visual objects （AVOs） over the DiffServ network with the QoS guarantee is proposed. MPEG-4 AVOs are e...The object-based scalable coding in MPEG-4 is investigated, and a prioritized transmission scheme of MPEG-4 audio-visual objects （AVOs） over the DiffServ network with the QoS guarantee is proposed. MPEG-4 AVOs are extracted and classified into different groups according to their priority values and scalable layers （visual importance）. These priority values are mapped to the 1P DiffServ per hop behaviors （PHB）. This scheme can selectively discard packets with low importance, in order to avoid the network congestion. Simulation results show that the quality of received video can gracefully adapt to network state, as compared with the ‘best-effort＇ manner. Also, by allowing the content provider to define prioritization of each audio-visual object, the adaptive transmission of object-based scalable video can be customized based on the content.展开更多
HAS(HTTP Adaptive Streaming)能够实现流畅播放和视频质量的平衡,为用户提供更好的服务质量体验。大多数基于HAS的流媒体用户体验质量(Quality of Experience,QoE)模型考虑了当前系统或网络条件,但对用户所处环境的客观影响、用户心理...HAS(HTTP Adaptive Streaming)能够实现流畅播放和视频质量的平衡,为用户提供更好的服务质量体验。大多数基于HAS的流媒体用户体验质量(Quality of Experience,QoE)模型考虑了当前系统或网络条件,但对用户所处环境的客观影响、用户心理因素的考虑较少。面向移动流媒体客户端的应用场景,从客观感知影响参数和心理效应影响参数两个方面来考虑移动端流媒体的QoE影响因素,设计用户QoE评估模型。提出移动设备抖动状态检测和用户观看位置检测方法,并将设备抖动状态、用户观看位置与流媒体服务质量相结合,再根据心理学系列位置效应来综合评估用户的质量体验情况。最后通过实验证明了所提的用户QoE模型能够提供准确有效且符合用户实际体验的QoE评估结果。展开更多
阐述了基于教考分离的高校试卷库管理系统的设计与实现.基于Visual Basic6.0和Access2003数据库,系统采用ActiveX Data Objects数据库技术、对象链接和嵌入技术、ADO的流对象和富文本框RichTextBox控件,将试卷电子文档以二进制数据的形...阐述了基于教考分离的高校试卷库管理系统的设计与实现.基于Visual Basic6.0和Access2003数据库,系统采用ActiveX Data Objects数据库技术、对象链接和嵌入技术、ADO的流对象和富文本框RichTextBox控件,将试卷电子文档以二进制数据的形式存入Access数据库的OLE字段,并保存试卷相关的重要信息,以便能有效地管理和重复利用这些重要的试卷数据.系统具有规模小、功能适用、单机操作、有一定的安全性、操作简单等特点,适合各级各类学校试卷管理工作之用.展开更多
文摘The object-based scalable coding in MPEG-4 is investigated, and a prioritized transmission scheme of MPEG-4 audio-visual objects （AVOs） over the DiffServ network with the QoS guarantee is proposed. MPEG-4 AVOs are extracted and classified into different groups according to their priority values and scalable layers （visual importance）. These priority values are mapped to the 1P DiffServ per hop behaviors （PHB）. This scheme can selectively discard packets with low importance, in order to avoid the network congestion. Simulation results show that the quality of received video can gracefully adapt to network state, as compared with the ‘best-effort＇ manner. Also, by allowing the content provider to define prioritization of each audio-visual object, the adaptive transmission of object-based scalable video can be customized based on the content.
文摘HAS(HTTP Adaptive Streaming)能够实现流畅播放和视频质量的平衡,为用户提供更好的服务质量体验。大多数基于HAS的流媒体用户体验质量(Quality of Experience,QoE)模型考虑了当前系统或网络条件,但对用户所处环境的客观影响、用户心理因素的考虑较少。面向移动流媒体客户端的应用场景,从客观感知影响参数和心理效应影响参数两个方面来考虑移动端流媒体的QoE影响因素,设计用户QoE评估模型。提出移动设备抖动状态检测和用户观看位置检测方法,并将设备抖动状态、用户观看位置与流媒体服务质量相结合,再根据心理学系列位置效应来综合评估用户的质量体验情况。最后通过实验证明了所提的用户QoE模型能够提供准确有效且符合用户实际体验的QoE评估结果。
文摘阐述了基于教考分离的高校试卷库管理系统的设计与实现.基于Visual Basic6.0和Access2003数据库,系统采用ActiveX Data Objects数据库技术、对象链接和嵌入技术、ADO的流对象和富文本框RichTextBox控件,将试卷电子文档以二进制数据的形式存入Access数据库的OLE字段,并保存试卷相关的重要信息,以便能有效地管理和重复利用这些重要的试卷数据.系统具有规模小、功能适用、单机操作、有一定的安全性、操作简单等特点,适合各级各类学校试卷管理工作之用.
