Oliver Hohlfeld

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The estimation of quality for real time services over telecommunication networks requires realistic models in order to generate impairments and failures during transmission. Starting with the classical Gilbert-Elliot model, we derive the second order statistics over arbitrary time scales and fit the parameters to match the packet loss pattern of traffic(More)
Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by SVC.(More)
Video streaming applications are a major driver for the evolution of the future Internet. In this paper we introduce a framework for QoE management for video streaming systems based on the H.264/SVC codec, the scalable extension of H.264/AVC. A relevant feature is to control the user perceived quality of experience (QoE) by exploiting parameters offered by(More)
Content and services which are offered for free on the Internet are primarily monetized through online advertisement. This business model relies on the implicit agreement between content providers and users where viewing ads is the price for the "free" content. This status quo is not acceptable to all users, however, as manifested by the rise of ad-blocking(More)
The migration of voice communication from the Public Switched Telephone Network to the Internet pushes the need to adequately size network resources such as buffers and capacity. This paper addresses the problem of how these resources should be scaled in the number of voice flows N in order to guarantee predefined packet loss probabilities and end-to-end(More)
Real-time Internet services are gaining in popularity due to rapid provisioning of broadband access technologies. Delivery of high quality of experience (QoE) is important for consumer acceptance of multimedia applications. IP packet level errors affect QoE and the resulting quality degradations have to be taken into account in network operation. We derive(More)
Traffic engineering and an economical provisioning of bandwidth is crucial for network providers in times of high competition in broadband access networks. We investigate the efficiency of caching as an option to shorten end-to-end paths and delays while at the same time reducing traffic loads. The portion of HTTP based distribution of cacheable content on(More)
The class of Gupta-Kumar results give the asymptotic throughput in multi-hop wireless networks but cannot predict the throughput behavior in networks of typical size. This paper addresses the non-asymptotic analysis of the multihop wireless communication problem and provides, for the first time, closed-form results on multi-hop throughput and delay(More)
On March 17, 2013, an Internet census data set and an accompanying report were released by an anonymous author or group of authors. It created an immediate media buzz, mainly because of the unorthodox and unethical data collection methodology (i.e., exploiting default passwords to form the Carna botnet), but also because of the alleged unprecedented large(More)