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.

Artifact types in information systems design science – a literature review

Abstract: Many information systems researchers designate their work as design science referring to the term “IT artifact” and the categorization systems that have emerged under this label Alas, there is no consensus at this point as to what the research output in design science is and what types of artifacts exist Using a widely accepted artifact typology would strengthen the scientific discussion and ease the categorization of contributions Based on a literature review of all DESRIST publications and a special MISQ issue on design science, we derived such a typology We identified eight relevant artifact types and related our typology to existing ones With this contribution, we hope to enable a discussion about what legitimate design science outputs and their main types are.

REPLEX: dynamic traffic engineering based on wardrop routing policies

Abstract: One major challenge in communication networks is the problem of dynamically distributing load in the presence of bursty and hard to predict changes in traffic demands. Current traffic engineering operates on time scales of several hours which is too slow to react to phenomena like flash crowds or BGP reroutes. One possible solution is to use load sensitive routing. Yet, interacting routing decisions at short time scales can lead to oscillations, which has prevented load sensitive routing from being deployed since the early experiences in Arpanet.However, recent theoretical results have devised a game theoretical re-routing policy that provably avoids such oscillation and in addition can be shown to converge quickly. In this paper we present ReplEx, a distributed dynamic traffic engineering algorithm based on this policy. Exploiting the fact that most underlying routing protocols support multiple equal-cost routes to a destination, it dynamically changes the proportion of traffic that is routed along each path. These proportions are carefully adapted utilising information from periodic measurements and, optionally, information exchanged between the routers about the traffic condition along the path.We evaluate the algorithm via simulations employing traffic loads that mimic actual Web traffic, i. e., bursty TCP traffic, and whose characteristics are consistent with self-similarity. The simulations quickly converge and do not exhibit significant oscillations on both artificial as well as real topologies, as can be expected from the theoretical results.

Stochastic Games for Security in Networks with Interdependent Nodes

Abstract: This paper studies a stochastic game theoretic approach to security and intrusion detection in communication and computer networks. Specifically, an Attacker and a Defender take part in a two-player game over a network of nodes whose security assets and vulnerabilities are correlated. Such a network can be modeled using weighted directed graphs with the edges representing the influence among the nodes. The game can be formulated as a non-cooperative zero-sum or nonzero-sum stochastic game. However, due to correlation among the nodes, if some nodes are compromised, the effective security assets and vulnerabilities of the remaining ones will not stay the same in general, which leads to complex system dynamics. We examine existence, uniqueness, and structure of the solution and also provide numerical examples to illustrate our model.

Security Games with Incomplete Information

Abstract: We study two-player security games which can be viewed as sequences of nonzero-sum matrix games played by an Attacker and a Defender. At each stage of the game iterations, the players make imperfect observations of each other's previous actions. The underlying decision process can be viewed as a fictitious play (FP) game, but what differentiates this class from the standard one is that the communication channels that carry action information from one player to the other, or the sensor systems, are error prone. Two possible scenarios are addressed in the paper: (i) if the error probabilities associated with the sensor systems are known to the players, then our analysis provides guidelines for each player to reach a Nash equilibrium (NE), which is related to the NE of the underlying static game; (ii) if the error probabilities are not known to the players, then we study the effect of observation errors on the convergence to the NE and the final outcome of the game. We discuss both the classical FP and the stochastic FP, where for the latter the payoff function of each player includes an entropy term to randomize its own strategy, which can be interpreted as a way of concealing its true strategy.

MobiAd: private and scalable mobile advertising

Abstract: We introduce MobiAd; a scalable, location-aware, personalised and private advertising system for mobile platforms. Advertising is the driving force behind many websites and service providers on the Internet. With the ever-increasing number of smart phones, there is a fertile market for personalised and localised advertising. They key benefit of using mobile phones is to take advantage of the vast amount of information on the phones and the locations of interest to the user in order to provide personalised ads. Preservation of user privacy is however essential for successful deployment of such a system. MobiAd would perform a range of data mining tasks in order to maintain an interest profile on the user's phone, and use the infrastructure network to download and display relevant ads and reports the clicks via a Delay Tolerant Networking (DTN) protocol. In this paper we provide an overview into existing advertising systems and privacy concerns on mobile phones, in addition to the scalable local ad download and privacy-aware DTN-based click report dissemination methods that we propose for MobiAd.