Yuansong Qiao

Performance Evaluation of Multimedia Content Distribution Over Multi-Homed Wireless Networks

The growing availability of IP based heterogeneous wireless access technologies coupled with the increasing capabilities of mobile devices is creating opportunities for multimedia distribution. Through its multi-homing feature, the ability to support multiple network connections in a single end to end association, the transport layer Stream Control Transmission Protocol (SCTP) can enable seamless and transparent communication sessions over multiple heterogeneous networks. This paper analyzes the performance of multimedia distribution when making use of two multi-homing SCTP-based approaches: Single Path Transfer and Concurrent Multi-path Transfer, in which a single or all paths within an association are used simultaneously for data transmission. In this investigation various retransmission policies and different parameter sets are used in turn and recommendations are made for achieving best results during video delivery. In order to perform this study a novel realistic evaluation tool-set was proposed and is described, which can simulate video delivery over SCTP. Our simulation results and analysis show how to optimize the transmission of multimedia content over SCTP associations in both single and multipath scenarios.

SCTP Performance Issue on Path Delay Differential

This paper studies the effect of path delay on SCTP performance. It focuses on the SCTP fast retransmit algorithm and demonstrates that the performance in the current retransmission strategy will degrade acutely when the secondary path delay is less than the primary path delay at a certain level. The performance degradation is due to the disordered SACKs and constant congestion window size during the fast retransmit phase. Some modifications aimed at these problems are proposed and evaluated. This paper also identifies that the cause of the performance degradation in SCTP is a result of the single path configuration oriented design of the current fast retransmit algorithm. Several fast retransmission strategies are evaluated for different path delay and bandwidth configurations.

An evaluation of Heart Rate and ElectroDermal Activity as an objective QoE evaluation method for immersive virtual reality environments

Recently, we have seen an emergence of affordable Head Mounted Displays (HMD) such as the Oculus Rift, HTC Vive, and the PS4 Project Morpheus which allow users to experience 3D virtual reality (VR). These types of hardware aim to facilitate new and novel experiences for users above and beyond what is possible with traditional audiovisual displays. However, a very limited number of studies exist in the literature to determine the influence of these technologies on user Quality of Experience (QoE). In order to evaluate QoE as users consume VR content, this paper proposes the use of affordable consumer electronics to capture objective physiological metrics: Heart Rate (HR) and ElectroDermal Activity (EDA). Our findings indicate different HR and EDA dependent on VR and non-VR environments. Additionally, we examine the relationship between these objective metrics and user QoE captured via a post-test questionnaire. To the best of the authors knowledge, this is the first work which demonstrates a tangible relationship between the EDA/HR combination and user QoE of immersive VR environments.

Olfaction-Enhanced Multimedia: A Survey of Application Domains, Displays, and Research Challenges

Recently, the concept of olfaction-enhanced multimedia applications has gained traction as a step toward further enhancing user quality of experience. The next generation of rich media services will be immersive and multisensory, with olfaction playing a key role. This survey reviews current olfactory-related research from a number of perspectives. It introduces and explains relevant olfactory psychophysical terminology, knowledge of which is necessary for working with olfaction as a media component. In addition, it reviews and highlights the use of, and potential for, olfaction across a number of application domains, namely health, tourism, education, and training. A taxonomy of research and development of olfactory displays is provided in terms of display type, scent generation mechanism, application area, and strengths/weaknesses. State of the art research works involving olfaction are discussed and associated research challenges are proposed.

Performance Evaluation of Distributing Real-Time Video Over Concurrent Multipath

Recent research on Concurrent Multipath Transfer (CMT) and CMT with a Potentially-Failed destination state (CMT-PF) uses the transport layer multi-homing protocol Stream Control Transmission Protocol (SCTP) to increase application throughput by distributing transmitted data across multiple end-to-end paths. This paper investigates and evaluates the performance of CMT with Partial Reliability (CMT-PR) and CMT-PF with Partial Reliability (CMT-PF-PR), novel extensions of SCTP for real-time video distribution. The Evalvid-CMT platform was implemented in the University of Delawares SCTP/CMT ns-2 module to perform emulation experiments in order to compare CMT and CMT-PR, CMT-PF and CMT-PF-PR,respectively. The results presented in the paper show how the CMT-PR and CMT-PF-PR outperform CMT and CMT-PF respectively. Consequently the former are suggested as strategies for real-time video concurrent multipath transmissions.

The Impact of Scent Type on Olfaction-Enhanced Multimedia Quality of Experience

In the quest to increase user perceived quality of experience (QoE), the classic audio-visual content paradigm can be extended to include media components that stimulate other human senses. Among these, olfaction-enhanced multimedia has attracted significant attention, as it is both attractive from user point of view and challenging from research perspective. This paper presents the results of two subjective studies which analyzed user QoE of olfaction-enhanced multimedia. Diverse scent types and video content were considered. In particular, QoE levels were studied when one and two olfaction stimuli enhanced audiovisual media. The results presented show that scent type influences user QoE. Statistically significant differences between pleasant and unpleasant scent types existed. Also, in certain cases, users were prepared to forgive the presence of unpleasant scent types with respect to QoE. Finally, users reported a clear preference for olfaction presented after the video sequence with which the olfaction effect should be synchronized, as opposed to before the video sequence.

Comparative Study of Real-Time Multimedia Transmission over Multi-homing Transport Protocols

The availability of multimedia applications suitable for deployment using 3G and GPRS networks has led to a requirement for end-to-end quality of service. More efficient mechanisms are needed in order to provide the required end user quality of service in wireless data networks. This paper investigates the performance implications of transmitting real-time multimedia content over a multi-homed transport protocol in a manner which is tolerant of network failure. It evaluates video quality with different retransmission policies combined with various path failure detection thresholds, path bandwidths, delays and loss rate conditions through Partial Reliable Stream Control Transmission Protocol (PR-SCTP). A solution called Evalvid-SCTP, which is a trace driven simulation of MPEG-4 video over SCTP, was designed to achieve the performance evaluation.

Analysis of Real-time Multimedia Transmission over PR-SCTP with Failover Detection Delay and Reliability Level Differential

The growing availability of different wireless access technologies provides the opportunity for real-time distribution of multimedia content using multi-homing technology. Investigating the behaviors and quality of such applications under heavy network load is necessary. This paper studies the effect of path failure detection threshold and reliability level on Stream Control Transmission Protocol Partial Reliability Extension (PR-SCTP) performance in symmetric and asymmetric path conditions respectively with different path loss rates. The platform Evalvid-SCTP implemented in the University of Delaware’s SCTP ns-2 module performs the emulation experiment.

Congestion control with the fixed cost at the domain border

CSFQ is designed as an open loop controller to provide fair best effort service, which supervises the bandwidth consumption of pre-flow and has become helpless after P2P flows dominate the traffic of the Internet. Token- Based Congestion Control (TBCC) is based on a closed loop congestion control principle, which restricts the token resource consumed by an end-user and provides fair services with O(1) complexity. As Self-Verifying CSFQ, it is heavy load to police inter-domain traffic for lack of trust. In this paper, Token- Limited Congestion Control (TLCC) is presented, which appends inter-domain congestion control to TBCC. TLCC provides the fixed cost to the inter-domain congestion charging with O(1) complexity. By simulations, it is demonstrated that TLCC can provide stable and fair bandwidth allocation across the domain border.

An Analysis of Alterations to the SCTP RTO Calculation Mechanism for WLAN Environments

As a connection oriented transport layer protocol the Stream Control Transmission Protocol (SCTP) inherits many of the features of the Transmission Control Protocol (TCP) including the mechanism by which Retransmission Timeout (RTO) is calculated. Previous investigations have established that the mechanism through which SCTP calculates RTO is inappropriate in Wireless LAN (WLAN) environments. This paper investigates the performance implications of changes to the SCTP RTO calculation mechanism. In particular alterations to the parameters α, the smoothing factor, and β, the delay variance factor are investigated. Results indicate that performance improvements are achievable through careful selection of α and β values. Throughput improvements of 63% over the default mechanism defined in RFC 4960 are described. These performance improvements however, while significant, still can not address the switchover delays which result from the distortions caused by continuously increasing RTT values in WLAN environments.