scholarly journals Client-Driven Joint Cache Management and Rate Adaptation for Dynamic Adaptive Streaming over HTTP

2013 ◽  
Vol 2013 ◽  
pp. 1-16 ◽  
Author(s):  
Chenghao Liu ◽  
Miska M. Hannuksela ◽  
Moncef Gabbouj
Keyword(s):  
Rate Adaptation ◽  
Cache Management ◽  
Adaptive Streaming ◽  
Adaptation Algorithm ◽  
Proxy Cache ◽  
Proxy Caches ◽  
Simulation Results ◽  
And Storage ◽  
Media Data ◽  
Adaptation Method

Due to the fact that proxy-driven proxy cache management and the client-driven streaming solution of Dynamic Adaptive Streaming over HTTP (DASH) are two independent processes, some difficulties and challenges arise in media data management at the proxy cache and rate adaptation at the DASH client. This paper presents a novel client-driven joint proxy cache management and DASH rate adaptation method, named CLICRA, which moves prefetching intelligence from the proxy cache to the client. Based on the philosophy of CLICRA, this paper proposes a rate adaptation algorithm, which selects bitrates for the next media segments to be requested by using the predicted buffered media time in the client. CLICRA is realized by conveying information on the segments that are likely to be fetched subsequently to the proxy cache so that it can use the information for prefetching. Simulation results show that the proposed method outperforms the conventional segment-fetch-time-based rate adaptation and the proxy-driven proxy cache management significantly not only in streaming quality at the client but also in bandwidth and storage usage in proxy caches.

scholarly journals Enhancing QoE for Mobile Users by Environment-Aware HTTP Adaptive Streaming

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3645 ◽  
Author(s):  
Weizhan Zhang ◽  
Hao He ◽  
Shuyan Ye ◽  
Zhiwen Wang ◽  
Qinghua Zheng
Keyword(s):  
Video Quality ◽  
Rate Adaptation ◽  
Dynamic Network ◽  
Mobile Users ◽  
Adaptive Streaming ◽  
Adaptation Algorithm ◽  
Model Driven ◽  
Http Adaptive Streaming ◽  
Qoe Model

HTTP adaptive streaming (HAS) has become a dominated media streaming paradigm in today’s Internet, which enriches the user’s experience by matching the video quality with the dynamic network conditions. A range of HAS mechanisms have been proposed to enhance the Quality of Experience (QoE). However, existing mechanisms ignore the environmental impact in the QoE evaluation of mobile users, while the popularity of mobile video allows users to watch videos in diversified scenarios. In this paper, we propose an environment-aware HAS scheme that fully concentrates on the different criteria for evaluating video QoE under different environments. Using the advantage of the sensors in mobile phones, the scheme constructs and validates a video QoE model based on environment perception and then designs a model-driven, environment-aware HAS rate adaptation algorithm. We also evaluate the scheme with an environment-aware DASH (Dynamic Adaptive Streaming over HTTP) player in real mobile environments. Compared to the benchmark HAS mechanism, the experimental results demonstrate that our scheme can provide appropriate differentiated rate adaptation for different environments, resulting in a higher QoE.

The Sensitivity Simulation of Different Geometric Pretreatment in Method of Characteristics

2017 ◽  
Author(s):  
Tian XiaoRui ◽  
Zhou Tao ◽  
Li Zichao ◽  
Yu Tao
Keyword(s):  
Computational Efficiency ◽  
Method Of Characteristics ◽  
Azimuthal Angle ◽  
Reactor Core ◽  
Characteristic Line ◽  
Simulation Results ◽  
And Storage

In reactor core physics analysis,the research about the pre-processing of Method of Characteristic (MOC) including the generation and storage of characteristic line,the progress of calculation and the choosing of different quadrature set.In addition,doing some simulations,which is based on OpenMOC code and C5G7-MOX benchmark,about different parameters (including the track spacing,azimuthal angles and polar angles) and calculated its impacts on the computational efficiency and accuracy.the simulation results are as following:setting the track spacing as 0.1 cm or the azimuthal angle number as 4,the simulation results have better accuracy. Whether choosing the Leonard’s optimum quadrature set or the Tabuchi-Yamamoto quadrature set,the number of polar angles have tiny impact on accuracy.

scholarly journals Web Proxy Auto Discovery for Dynamically Created Web Proxies

2020 ◽  
Vol 245 ◽  
pp. 07026
Author(s):  
Dave Dykstra
Keyword(s):  
Distributed Database ◽  
Database System ◽  
General Purpose ◽  
Single Source ◽  
Sources Of Information ◽  
Proxy Cache ◽  
Proxy Caches ◽  
Distributed Database System ◽  
The Web

The WLCG Web Proxy Auto Discovery (WPAD) service provides a convenient mechanism for jobs running anywhere on the WLCG to dynamically discover web proxy cache servers that are nearby. The web proxy caches are general purpose for a number of different http applications, but different applications have different usage characteristics and not all proxy caches are engineered to work with the heaviest loads. For this reason, the initial sources of information for WLCG WPAD were the static configurations that ATLAS and CMS maintain for the Conditions data that they read through the Frontier Distributed Database system, which is the most demanding popular WLCG application for web proxy caches. That works well for use at traditional statically defined WLCG sites, but now that usage of commercial clouds is increasing, there is also a need for web proxy caches to dynamically register themselves as they are created. A package called Shoal had already been created to manage dynamically created web proxy caches. This paper describes the integration of the Shoal package into the WLCG WPAD system, such that both statically and dynamically created web proxy caches can be located from a single source. It also describes other improvements to the WLCG WPAD system since the last CHEP publication.

An Information Real-Time Transmission Algorithm Based on the Android Platform

2014 ◽  
Vol 701-702 ◽  
pp. 943-946
Author(s):  
Nian Fang Hong
Keyword(s):  
Real Time ◽  
Data Transmission ◽  
Cell Phone ◽  
Streaming Media ◽  
Time Synchronization ◽  
Adaptive Streaming ◽  
Time Increase ◽  
Limited Bandwidth ◽  
Real Time Transmission ◽  
Media Data

In the wireless network environment, a large number of applications based on cell phone have emerged. But it has appeared some problems such as large amount of data and limited bandwidth and higher quality transmission in the mobile streaming media data transmission. To solve these problems, this paper designs a bandwidth adaptive streaming media real-time synchronization algorithm. Algorithm firstly analysis the state of the network, and then through real-time increase or decrease the factor method to effectively adjust the code flow rate, thus improve the QoS of streaming in transmission; to meet the learners' online learning, for subsequent teaching and interaction provides a good technical support.

A fair server adaptation algorithm for HTTP adaptive streaming using video complexity

2018 ◽  
Vol 78 (9) ◽  
pp. 11203-11222 ◽  
Author(s):  
Ran Dubin ◽  
Raffael Shalala ◽  
Amit Dvir ◽  
Ofir Pele ◽  
Ofer Hadar
Keyword(s):  
Adaptive Streaming ◽  
Adaptation Algorithm ◽  
Http Adaptive Streaming ◽  
Video Complexity
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