Learn More
Real-time audio and video transmission over shared packet networks, such as the Internet, has become possible thanks to efficient data compression schemes and the provision of high-speed networks. Low-cost multimedia conferencing technology could benefit many users in different areas, such as remote collaboration, distance education and health-care. It is(More)
This paper presents an experiment comparing the relative impact of different types of degradation on subjective quality ratings of interactive speech transmitted over packet-switched networks. The experiment was inspired by observations made during a large-scale, long-term field trial of multicast conferencing. We observed that user reports of(More)
Internet Protocol (IP)-based videoconferencing technology can offer a low-cost means of collaboration and resource sharing on a national or global scale. This is potentially of interest to many users, especially in non-profit sectors such as education and healthcare. However, it has been questioned whether a best-effort network service can provide the(More)
1. ABSTRACT There is currently much discussion of Quality of Service (QoS) measurements at the network level of real-time multimedia services, but it is the subjective quality perceived by the user that will determine whether these applications are adopted. This paper argues that ITU-recommended methods for subjective quality assessment of speech and video(More)
Network congestion affects all users, but real-time multimedia communication is particularly vulnerable. It has been proposed that bandwidth reservation should be used to guarantee a certain quality of service (QoS) for such applications. In order to employ bandwidth reservation effectively, we need to know how much bandwidth a particular application(More)
It was hypothesized that rapid rather than slow re-warming following traumatic brain injury (TBI) and short-term hypothermia results in secondary, ultrastructural pathology. After stretch injury to the right optic nerve, adult guinea pigs were randomly allocated to one of six experimental groups. Either (1) sham (all procedures but not stretch-injured; n =(More)