HAS Based Empirical QoE Study over TCP and QUIC on Diverse Networks

HTTP adaptive streaming (HAS) is the de-facto standard for video services over the Internet delivering increased Quality of Experience (QoE) as a function of the network status. Such adaptive streaming atop HTTP relies predominantly on TCP as the reliable transport protocol. Recently, QUIC, an alternative of TCP transport, has emerged to overcome TCP’s native shortcomings and improve the HTTP-based applications QoE. This paper investigates three strategies (Rate, Buffer, and Hybrid) based adaptive bitrate streaming (ABS) algorithms behavioral performance over the traditional TCP and QUIC transport protocol. For this purpose, we experimentally evaluate different cellular network traces in a high-fidelity emulated testbed and compare the performance of ABS algorithms considering QoE metrics over TCP and QUIC. Our empirical results show that each ABS algorithm’s (Conventional, BBA, and Arbiter) QoE performance is biased for TCP. As a result, QUIC suffers the ineffectiveness of traditional state-of-art ABS algorithms to improve video streaming performance without specific changes.

A Reliable Transport Scheme for Human Opportunistic Networks

The human opportunistic networks (ONs) formed by hand-held smart devices can facilitate peer-to-peer communication when humans are on the move, despite contemporaneous end-to-end paths rarely existing. In some scenarios, where network resources, especially power, are scarce and the traffic is large, the data delivery is prone to poor user experience and unbounded delay, although the best effort mechanism “store-carry-forward” is used. To cope with that, most transport/routing schemes obtain an acceptable latency at the cost of energy resources. In real-life human ONs, however, excessive energy consumption will trigger passive participation of the relays in message forwarding, so as to save their limited energy resource. Thus, the reliability of these schemes may get worse in real-life human ONs. In this paper, a reliable transport scheme is developed by making an optimal trade-off between the file round-trip delay and the energy consumption of relays. We make use of acknowledgements and coding at the source to enable successful file delivery. When setting up the network model, the cache management rule referred as “full-duplex” strategy is formulated, and then a mathematical model is established to analyze the proposed scheme. This model describes the evolution of packet dissemination and allows both the mean file round-trip delay and the energy consumption up to the reception of the last acknowledgement by the source to be expressed. Subsequently, a new function based on these two metrics is proposed to reflect the number of files that can be delivered under time and energy constraints. Through optimization procedure, the configurations that can maximize the function are obtained; thus, the optimization of these two metrics is achieved. Numerous simulations and comparisons are conducted and the results verify the accuracy of the analytical model. Comparison results show that with limited energy and passive relays, the proposed transport scheme can significantly reduce the energy consumption of file delivery, which obviously alleviates the selfish behavior of nodes. Therefore, the reliability and stability of the communication service in human ONs are enhanced.

Diffuse or hitch a ride: how photoreceptor lipidated proteins get from here to there

Photoreceptors are polarized neurons, with specific subcellular compartmentalization and unique requirements for protein expression and trafficking. Each photoreceptor contains an outer segment (OS) where vision begins, an inner segment (IS) where protein synthesis occurs and a synaptic terminal for signal transmission to second-order neurons. The OS is a large, modified primary cilium attached to the IS by a slender connecting cilium (CC), the equivalent of the transition zone (TZ). Daily renewal of ~10% of the OS requires massive protein biosynthesis in the IS with reliable transport and targeting pathways. Transport of lipidated (‘sticky’) proteins depends on solubilization factors, phosphodiesterase δ (PDEδ) and uncoordinated protein-119 (UNC119), and the cargo dispensation factor (CDF), Arf-like protein 3-guanosine triphosphate (ARL3-GTP). As PDE6 and transducin still reside prominently in the OS of PDEδ and UNC119 germline knockout mice, respectively, we propose the existence of an alternate trafficking pathway, whereby lipidated proteins migrate in rhodopsin-containing vesicles of the secretory pathway.

A Joint Reliable Transport Strategy in Internet of Vehicles

Internet of Vehicles (IoV) is promising in bringing various data services from the traditional Internet to vehicle networks. Therefore, a reliable transport service in IoV needs to cross multiple heterogeneous networks with quite different characteristics. However, no single transport protocol is able to cope with such complex scenarios comprehensively with efficient data transmission all the way. To this end, we provide a solution named the joint reliable transport strategy (JR-TS) that selects different transport protocols on demand based on various scenarios, and builds an entire end-to-end route by linking all these transport protocols head to tail. Currently, JR-TS has already included three types of transport protocols to adapt to three typical network scenarios. With the proper implementations and settings, JR-TS can improve end-to-end transport performance and cache capacity efficiency more effectively than any single transport protocol.