Analysis and modelling of traffic produced by adaptive HTTP-based video

The increase of HTTP-based video popularity causes that broadband and Internet service providers' links transmit mainly multimedia content. Network planning, traffic engineering or congestion control requires an understanding of the statistical properties of network traffic; therefore, it is desirable to investigate the characteristic of traffic traces generated by systems which employ adaptive bit-rate streaming. Our first contribution is an investigation of traffic originating from 120 client-server pairs, situated in an emulated content distribution network, and multiplexed onto a single network link. We show that the structure of the traffic is distinct from the structure generated by the first and second generation of HTTP video systems, and furthermore, not similar to the structure of general Internet traffic. The obtained traffic exhibits negative and positive correlations, anti-persistence, and its distribution function is skewed to the right. Our second contribution is an approximation of the traffic by ARIMA/FARIMA processes blue and artificial neural networks. As we show, the obtained traffic models are able to enhance the performance of an adaptive streaming algorithm. Document type: Articl

On the Influence of Network Impairments on YouTube Video Streaming, Journal of Telecommunications and Information Technology, 2012, nr 3

Video sharing services like YouTube have become very popular which consequently results in a drastic shift of the Internet traffic statistic. When transmitting video content over packet based networks, stringent quality of service (QoS) constraints must be met in order to provide the comparable level of quality to a traditional broadcast television. However, the packet transmission is influenced by delays and losses of data packets which can have devastating influence on the perceived quality of the video. Therefore, we conducted an experimental evaluation of HTTP based video transmission focusing on how they react to packet delay and loss. Through this analysis we investigated how long video playback is stalled and how often re-buffering events take place. Our analysis revealed threshold levels for the packet delay, packet losses and network throughput which should not be exceeded in order to preserve smooth video transmission

The Quality of Hospital Services in A Multidimensional Approach

Abstract The paper is a synthetic version of the broader study, which the authors have done within the scope of the project funded by the Ministry of Science and Higher Education. Its aim was to propose a comprehensive method for assessing the quality of service of public ut ility entities. More precisely it can be said that the goal was to a designate a model that regardless of the type and area of activity of public utility entities will allow to assess their work in the sa me way, using the same method in each of the proposed dimensions. Given the limited scope of the present study it will be restricted to consideration of economic, professional, process, professional and social d imensions of the assessment of one of the public health service entities, name ly the hospital

Propozycja syntetycznego miernika oceniającego działalność instytucji użyteczności publicznej

The proposal measure synthetic evaluation of the activities of public institutions Presented article is continuation previous paper [Biernacki, 2010]. Author proposes own evaluation method in 5 dimensions of public utilities: (1) economic (effeciency); (2) professional (effectiveness); (3) process; (4) personal (customer satisfaction); (5) social (improvement in public welfare). This paper presents comprehensive evaluation method in activity public utilities, based on standardized and comparable method in five dimensions. Empirical examples present core methotology