scholarly journals Unbiased experiments in congested networks

2021 ◽  
Author(s):  
Bruce Spang ◽  
Veronica Hannan ◽  
Shravya Kunamalla ◽  
Te-Yuan Huang ◽  
Nick McKeown ◽  
...  
Keyword(s):  
Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 948
Author(s):  
Carlos Eduardo Maffini Santos ◽  
Carlos Alexandre Gouvea da Silva ◽  
Carlos Marcelo Pedroso

Quality of service (QoS) requirements for live streaming are most required for video-on-demand (VoD), where they are more sensitive to variations in delay, jitter, and packet loss. Dynamic Adaptive Streaming over HTTP (DASH) is the most popular technology for live streaming and VoD, where it has been massively deployed on the Internet. DASH is an over-the-top application using unmanaged networks to distribute content with the best possible quality. Widely, it uses large reception buffers in order to keep a seamless playback for VoD applications. However, the use of large buffers in live streaming services is not allowed because of the induced delay. Hence, network congestion caused by insufficient queues could decrease the user-perceived video quality. Active Queue Management (AQM) arises as an alternative to control the congestion in a router’s queue, pressing the TCP traffic sources to reduce their transmission rate when it detects incipient congestion. As a consequence, the DASH client tends to decrease the quality of the streamed video. In this article, we evaluate the performance of recent AQM strategies for real-time adaptive video streaming and propose a new AQM algorithm using Long Short-Term Memory (LSTM) neural networks to improve the user-perceived video quality. The LSTM forecast the trend of queue delay to allow earlier packet discard in order to avoid the network congestion. The results show that the proposed method outperforms the competing AQM algorithms, mainly in scenarios where there are congested networks.


Author(s):  
Oded Cats ◽  
Jens West

The distribution of passenger demand over the transit network is forecasted using transit assignment models which conventionally assume that passenger loads satisfy network equilibrium conditions. The approach taken in this study is to model transit path choice as a within-day dynamic process influenced by network state variation and real-time information. The iterative network loading process leading to steady-state conditions is performed by means of day-to-day learning implemented in an agent-based simulation model. We explicitly account for adaptation and learning in relation to service uncertainty, on-board crowding and information provision in the context of congested transit networks. This study thus combines the underlying assignment principles that govern transit assignment models and the disaggregate demand modeling enabled by agent-based simulation modeling. The model is applied to a toy network for illustration purposes, followed by a demonstration for the rapid transit network of Stockholm, Sweden. A full-scale application of the proposed model shows the day-to-day travel time and crowding development for different levels of network saturation and when deploying different levels of information availability.


Computing ◽  
2015 ◽  
Vol 98 (3) ◽  
pp. 235-256 ◽  
Author(s):  
Kawuu W. Lin ◽  
Sheng-Hao Chung ◽  
Chun-Cheng Lin

2014 ◽  
Vol 1030-1032 ◽  
pp. 2019-2023 ◽  
Author(s):  
Yi Luo ◽  
Da Lin Qian

In this paper, we proposed a network efficiency measure for congested networks based on the user equilibrium, travel costs, demand and road resources being occupied. Compares the network efficiency on expressway before and after the bus lane operation, the results show that the exclusive bus lane stimulates demand for mass transportation, which greatly improves the efficiency of transit operation. Finally, combined with the survey data, we are clear that how to improve the level of services of public transportation and how to attract more travelers to use buses for commuting.


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