Deutsche Telekom

About: Deutsche Telekom is a company organization based out in Welwyn Garden City, United Kingdom. It is known for research contribution in the topics: Telecommunications network & Terminal (electronics). The organization has 3473 authors who have published 5208 publications receiving 65429 citations. The organization is also known as: DTAG & German Telecom.

Benefits of SOA: Evaluation of an implemented scenario against alternative architectures

Abstract: Service-oriented architecture (SOA) is based on a design principle for business software systems. The SOA movement has taken up momentum, especially because of widespread middleware vendor support, e.g. by IBM, HP, BEA, Microsoft, Sun, Software AG, TIBCO, Oracle, SAP and others. Still answers to questions of how the target architecture should look like and what the advantages over other architectures are remain open. We have implemented a scenario based on free software, which consists of a well-defined service-oriented target architecture. In this article, we compare the used service-oriented approach with other state-of-theart architectures to show that changeability and efficiency improve compared to alternative architectures.

At home in the lab: Assessing audiovisual quality of HTTP-based adaptive streaming with an immersive test paradigm

Abstract: In this paper, we assess audiovisual quality of HTTP Adaptive Streaming using a novel subjective test design. The goal of this test was to systematically study the impact of both quality variations and stalling events on remembered quality. To gather more ecologically valid results, we wanted to reach a degree of test subject engagement and attention closer to real-life video viewing than what is achieved in traditional lab tests. To this aim, we used a novel test design method: the “immersive” paradigm, where subjects never see the same source stimulus twice. A total of 66 source clips of one minute length have been shown, selected from online video services. Together with qualitative results obtained from questionnaires, we can confirm previously reported effects, such as the impact of quality switching frequency. We also present new findings on the interaction of stalling events and quality drops. Finally, the contribution highlights that a long duration test of over one hour is feasible using the immersive paradigm while keeping subjects entertained.

Enhanced authentication and/or enhanced identification of a secure element of a communication device

Abstract: A method for enhanced authentication and/or enhanced identification of a secure element of a user equipment includes: transmitting a first message to a secure element; receiving a second message, from the secure element at a first server entity, the second message including at least the signed public key and a signature information, wherein the signing message content includes at least one information element that is omitted in the second message; transmitting a third message, to the second server entity, the third message including at least the signed public key and the signature information, wherein the signing message content is accessible to or derivable by the second server entity in view of a verification of the signature information contained in the second message for authentication and/or identification purposes.

On the Benefit of Virtualization: Strategies for Flexible Server Allocation

Abstract: Virtualization technology facilitates a dynamic, demand-driven allocation and migration of servers. This paper studies how the flexibility offered by network virtualization can be used to improve Quality-of-Service parameters such as latency, while taking into account allocation costs. A generic use case is considered where both the overall demand issued for a certain service (for example, an SAP application in the cloud, or a gaming application) as well as the origins of the requests change over time (e.g., due to time zone effects or due to user mobility), and we present online and optimal offline strategies to compute the number and location of the servers implementing this service. These algorithms also allow us to study the fundamental benefits of dynamic resource allocation compared to static systems. Our simulation results confirm our expectations that the gain of flexible server allocation is particularly high in scenarios with moderate dynamics.

A Physiological Approach to Determine Video Quality

Abstract: Video quality has turned out to be a crucial aspect of multimodal transmission services. Most common video quality tests rely on a conscious judgment of test participants reflecting their internal quality perception. But it is not completely clear how this conscious rating is formed, neither in the auditory nor in the visual domain. Initial audio tests with Electroencephalography (EEG) have shown that EEG recordings can be used as a sensitive and non-intrusive method for quality assessment. In this paper we conducted first experiments of pure video quality tests with EEG to complement this approach in the visual domain. One of the goals for this experiment was to show that there is a different pattern in the EEG data for cases with no distortion compared to cases when there was a distortion and the subject recognized this in the subjective test.