German Network Agency

About: German Network Agency is a other organization based out in Bonn, Germany. It is known for research contribution in the topics: Software-defined radio & Foreign direct investment. The organization has 14 authors who have published 17 publications receiving 204 citations.

ETSI reconfigurable radio systems: status and future directions on software defined radio and cognitive radio standards

Abstract: This article details the current work status of the ETSI Reconfigurable Radio Systems Technical Committee, positions the ETSI work with respect to other standards efforts (IEEE 802, IEEE SCC41) as well as the European Regulatory Framework, and gives an outlook on the future evolution. In particular, software defined radio related study results are presented with a focus on SDR architectures for mobile devices such as mobile phones. For MDs, a novel architecture and inherent interfaces are presented enabling the usage of SDR principles in a mass market context. Cognitive radio principles within ETSI RRS are concentrated on two topics, a cognitive pilot channel proposal and a Functional Architecture for Management and control of reconfigurable radio systems, including dynamic self-organizing planning and management, dynamic spectrum management, joint radio resource management. Finally, study results are indicated that are targeting a SDR/CR security framework.

Determinants of students' success at university

Abstract: This paper studies the determinants of academic success using a unique administrative data set of a German university. We show that high school grades are strongly associated with both graduation probabilities and final grades, whereas variables measuring social origin or income have only a smaller impact. Moreover, the link between high school performance and university success is shown to vary substantially across faculties. In some fields of study, the probability of graduating is rather low, while grades are quite good conditional on high school performance. In others, weaker students have a greater chance of graduating, but grades are more differentiated.

Gravity Models in R

Abstract: Gravity models are used to explain bilateral flows related to the sizes of bilateral partners, a measure of distance between them and other influences on interaction costs. The underlying idea is rather simple. The greater the masses of two bodies and the smaller the distance between them, the stronger they attract each other. This concept is applied to several research topics such as trade, migration or foreign direct investment. Even though the basic idea of gravity models is rather simple, they can become very complex when it comes to the choice of models or estimation methods. The package \textbf{gravity} targets to provide \proglang{R} users with the functions necessary to execute the most common estimation methods for gravity models, especially for cross-sectional data. Gravitatsmodelle werden verwendet, um bilaterale Strome zu erklaren. Dabei werden sowohl die Grosen und die Distanz der jeweiligen Partner als auch weitere Einflussfaktoren zur Erklarung herangezogen. Die zugrundeliegende Idee dieser Modelle beruht auf dem Gravitatsprinzip. Je schwerer zwei Korper und je kleiner deren Distanz zueinander, desto starker ist ihre gegenseitige Anziehungskraft. Dieses Konzept wird auf verschiedene Forschungsreiche angewendet, so zum Beispiel Handel, Migration und auslandische Direktinvestitionen. Auch wenn die zugrundeliegende Idee von Gravitatsmodellen eher einfach ist, so kann deren Schatzung je nach Wahl des zugrundegelegten okonomischen Zusammenhangs komplex werden. Das Paket \textbf{gravity} ermoglicht es \proglang{R}-Nutzern die gangigsten Verfahren fur Gravitatsmodelle in der Querschnittsanalyse zu verwenden.

Analyzing Modes of Foreign Entry: Greenfield Investment versus Acquisition

Abstract: This paper studies the entry decision of a multinational enterprise into a foreign market. Two alternative entry modes for a foreign direct investment are considered: Greenfield investment versus acquisition. In contrast to existing approaches, the acquisition price and the profits under both entry modes are endogenously determined. Interestingly we find that the optimal entry mode decision is affected by the competition intensity in the market in a non-monotonic way. When markets are very much or very little competitive, greenfield investment is the optimal entry mode, while for intermediate values it is acquisition.

Digital and dynamic certification in the framework of the novel revised R&TTE Directive in Europe

Abstract: The next revision of the R&TTE Directive, which represents the basic regulatory framework for wireless communication in Europe, is expected to be finalized in 2011. In particular, this new revision is expected to provide a novel framework for reconfigurable radio devices, for example building on Software Defined Radio features. Those devices may maintain one or multiple links to heterogeneous radio access technologies simultaneously. Also, new features may be added after the sale of the device via software download, such as the addition of a new radio access technology to selected mobile devices. This addition of new features to a device that is already on the market is obviously challenging from a certification perspective. For this purpose, this paper proposes novel approaches for updating certificates building on the novel concepts of dynamic Declaration of Conformity, CE Marking and Alert Symbol marking as they are discussed for example in ETSI Reconfigurable Radio Systems (ETSI RRS) standardization. Those new mechanisms will allow for the software upgrade of features that may affect certification of a mobile device.