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Title: An investigation into quality of service for distributed haptic virtual environments
Author: Yap, K. M.
Awarding Body: Queens University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2008
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The effective transmission of sense of touch (haptics) traffic presents a significant challenge to the current Internet architecture. It is clear that the Quality of Service (QoS) needed to support haptic feedback in networks will be significantly different from that used to support conventional real-time traffic such as voice or video. Haptic applications require a stringent QoS from the network for successful interaction in Distributed Virtual Environments (DVEs). Network impairments such as time delay, jitter and packet loss each have different (and severe) impacts on the user's haptic experience for haptic interaction. Network delay reduces the fidelity when touching a virtual object due to reduction of force response. Jitter and packet loss can cause abrupt force feedback. All of these can cause system instability. Hence, there is a need to investigate what QoS techniques can be used to support distributed haptic applications over the Internet, and how to compensate for impairments introduced by the underlying network.· This is particularly important because it has potential to improve performance of Distributed Haptic Virtual Environment (DHVE) applications. Two new m.ethodologies for improving the performance of distributed haptic applications over IP switched networks are presented. These are developed by considering both the network and application aspects. The first methodology uses a novel approach by providing QoS (i.e. Diffserv) for multimodal traffic flows. The QoS levels required for supporting networked haptic collaboration are determined. Haptic traffic is characterized and modeled by using a network simulation tool. This involves development of a simulation model for DHVE traffic based on empirical measurements. Subsequently, it is shown by simulation and through practical experimentation that haptic traffic in multimodal systems can be provided with specific service quality over a QoS-enabled network; which shows that the haptic experience is improved by reducing delay and increasing throughput by using specific QoS class from DiffServ for haptic traffic. The second methodology examines whether existing position prediction and delay compensation algorithms can be used to enhance the haptic performance under network impairments. A new peer-topeer test bed has been developed in order to provide position synchronization and haptic collaboration for distributed haptic applications. In addition, a new compensation algorithm is developed to mitigate the effects of burst packet loss. This is based on the use of interleaving to randomize burst errors across many packets. Results show that this algorithm improves haptic applications' tolerance to burst loss by up to 45%. It improves the original QoS threshold limits of 24% to 35% for the burst packet loss in achieving a stable haptic collaboration. The results will provide valuable knowledge to the designers of future DHVE applications and to the underlying networks that have to support them; which also provides both effective and efficient force and position collaboration among multiple (>2) users.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available