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Mangier J.,University of Vienna | Witzany C.,University of Vienna | Jorns O.,Telecommunications Research Center Vienna ftw | Schikuta E.,University of Vienna | And 2 more authors.
Concurrency Computation Practice and Experience | Year: 2010

Until now, the research community mainly focused on the technical aspects of Grid computing and neglected commercial issues. However, recently the community tends to accept that the success of the Grid is crucially based on commercial exploitation. In our vision Foster's and Kesselman's statement 'The Grid is all about sharing.' has to be extended by .. and making money out of it!'. To allow for the realization of this vision, the trustworthiness of the underlying technology needs to be ensured. This can be achieved by the use of Gridified Secure Electronic Transaction as a basic technology for trust management and secure accounting in the presented grid-based workflow. We present a framework, conceptually and technically, from the area of the Mobile-Grid, which justifies the Grid infrastructure as a viable platform to enable commercially successful business workflows. Copyright © 2009 John Wiley & Sons, Ltd. Source

Hyytia E.,Telecommunications Research Center Vienna ftw
2009 Proceedings of the 1st International Workshop on Security and Communication Networks, IWSCN 2009 | Year: 2010

Many of the cryptographic primitives can be used in several ways. One interesting application of the Shamir's secret sharing scheme in the context of privacy aware traffic monitoring is to escrow a secret key after m suspicious events have been observed [1]. In the proposed system, a so-called front-end component encrypts the monitored data traffic, which is then stored at the back-end. At the same time, the front-end analyzes the traffic, and if suspicious packets are observed, this is indicated to the back-end by revealing one share of the corresponding encryption key. Once m suspicious events have been detected, the backend can disclose the secret key, decrypt the particular traffic flow, and carry out further investigations. In this paper we study the secret sharing scheme as a counter at the limit when the threshold m is relatively large. We first analyze how the scheme behaves as m approaches the maximum possible value of p - 1, where p is a prime number (design parameter). Then, we also analyze a probabilistic version developed to overcome the limited counting range, or excessive reporting overhead, by revealing shares only with a certain probability after each event, and provide expressions describing the resulting inaccuracy from the introduced randomness. Finally, we also propose a hybrid solution to mitigate the otherwise detoriating performance by using a forward error correction scheme similar to LT codes to encode the shared secret revealing process. Source

Reichl P.,Telecommunications Research Center Vienna ftw
Annales des Telecommunications/Annals of Telecommunications | Year: 2010

Providing Quality of Service (QoS) differentiation in future IP-based networks is closely linked to the concurrent implementation of appropriate pricing and charging mechanisms. Thus, in recent years, a broad range of QoS-based charging mechanisms have been proposed, ranging from Paris Metro Pricing and effective bandwidth pricing to the Cumulus Pricing Scheme or the Contract and Balancing Mechanism. However, the strongly increasing interest in Quality of Experience (QoE/QoX) so far has not led to a comparable burst of research activity in the Internet Economics community. Therefore, in order to highlight this important paradigm shift froma charging perspective, we first will review the most prominent QoS-based charging schemes and provide some discussion on lessons learned. In the next step, we describe the imminent transition from QoS to QoX from an economic point of view and discuss recent proposals for pricing of QoX. The paper ends with an outlook on current and future work in this highly interesting research field.© Institut TELECOM and Springer-Verlag 2009. Source

Laner M.,Vienna University of Technology | Svoboda P.,Vienna University of Technology | Hasenleithner E.,Telecommunications Research Center Vienna ftw | Rupp M.,Vienna University of Technology
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011

Users expect mobile Internet access via 3G technologies to be comparable to wired access in terms of throughput and latency. HSPA achieves this for throughput, whereas delay is significantly higher. In this paper we measure the overall latency introduced by HSUPA and accurately dissect it into contributions of USB-modem (UE), base station (NodeB) and network controller (RNC). We achieve this by combining traces recorded at each interface along the data-path of a public operational UMTS network. The actively generated sample traffic covers real-time applications. Results show the delay to be strongly dependent on the packet size, with random components depending on synchronization issues. We provide models for latency of single network entities as well as accumulated delay. These findings allow to identify optimum settings in terms of low latency, both for application and network parameters. © 2011 Springer-Verlag. Source

Egger S.,Telecommunications Research Center Vienna ftw | Hossfeld T.,University of Wurzburg | Schatz R.,Telecommunications Research Center Vienna ftw | Fiedler M.,Blekinge Institute of Technology
2012 4th International Workshop on Quality of Multimedia Experience, QoMEX 2012 | Year: 2012

A considerable share of applications such as web or e-mail browsing, online picture viewing and file downloads imply waiting times for their users, which is due to the turn-taking of information requests by the user and correspoding response times until each request is fulfilled. Thus, end-user quality perception in the context of interactive data services is dominated by waiting times; the longer the latter, the less satisfied the user becomes. As opposed to heavily researched multimedia experience, perception of waiting times is still not strongly explored in the context of Quality of Experience (QoE). This tutorial will contribute to closing this gap. In its first part, it addresses perception principles and discusses their applicability towards fundamental relationships between waiting times and resulting QoE. It then investigates to which extent the same relationships can also be used to describe QoE for more complex services such as web browsing. Finally, it discusses applications where waiting times determine QoE, amongst other factors. For example, the past shift from UDP media streaming to TCP media streaming (e.g. youtube.com) has extended the relevance of waiting times also to the domain of online video services. In particular, user-perceived quality suffers from initial delays when applications are launched, as well as from freezes during the delivery of the stream. These aspects, which have to be traded against each other to some extent, will be discussed mainly for HTTP video streaming in the last part of this tutorial. © 2012 IEEE. Source

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