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Optimization techniques always play an important role in designing high-performance wireless systems. This presented thesis studies a selected set of optimization problems for different kinds of wireless networks, making use of mathematical programming techniques to find optimal solutions and of efficient heuristics to find near-optimal solutions. The basic contribution of the thesis consists in a

Given a weighted directed graph where some arcs can fail while others are reliable, we aim to compute a shortest pair of failure-disjoint paths. If a reliable arc is used by both paths, its cost is counted only once. We present a polynomial time algorithm to solve the problem.

To be able to connect wirelessly to the internet is nowadays a part of everyday life and the number of wireless devices accessing wireless networks worldwide are increasing rapidly. However, with the increasing number of wireless devices and applications and the amount available bandwidth, spectrum shortage is an issue. A promising way to increase the amount of available spectrum is to utilize fre

We derive the interarrival distribution of a workload input process which is a variation of the infinite source Poisson process for packet traffic. It accounts for long-range dependence and self-similarity exhibited by real traces in the Internet. The packet generation process is compound Poisson over each session which has a heavy tailed distribution. Considering the dependence induced by the wor

Maturity models are widely used in process improvement. The users of a maturity model should be confident that the weak points of the assessed processes can be found, and that the most valuable changes are introduced. Therefore, the evaluation of maturity models is an important activity. In this paper, a mapping study of the literature on the evaluation of maturity models is presented. Two databas

In this study, the authors investigate the resistance of Boolean functions against fast algebraic attacks and deduce a bound between fast algebraic immunity and higher-order non-linearity (it is the first time that a bound between these two cryptographic criteria is given). The authors then show that the fast algebraic immunity of the following two classes of Boolean functions is not good: (a) The

Abstract in Undetermined[Context and motivation] There is considerable flexibility in requirements specifications (both functional and non-functional), as well as in the features of available OSS components. This allows a collaborative matching and negotiation process between stakeholders such as: customers, software contractors and OSS communities, regarding desired requirements versus available

Lightpath reconfiguration is a networking task that can be performed in order to improve resource utilization. The lightpath reconfiguration problem becomes nontrivial when a new set of lightpaths requires the release of resources previously seized by the (working) lightpaths currently in place, but, in order to ensure continuity of the traffic flow, the working lightpaths cannot be torn down befo

Reliability in Ricean multiple-input-multiple-output (MIMO) channels is crucial for safety related vehicle-tovehicle (V2V) applications. Due to the time variability of vehicular communication channel, it is very significant to study the temporal evolution of channel characterization criteria. We present evaluation results of the temporal evolution of the spectral efficiency from channel sounder me

The COST2100 channel model is a reference channel model which provides dynamic multiple-input multiple-output channel responses for radio system simulations. In this paper, channels created by the COST2100 model were compared to channel measurements in order to understand behaviours of the model. Model parameters of the COST2100 model were derived by dynamic double-directional channel measurements

With the open and big data movement in full swing, data sharing becomes more ubiquitous and more often crosses sectoral boundaries. The promise of data to help address societal issues and foster innovation requires public organizations to work together with businesses and researchers. Data collaboratives whereby actors collaborate to share and use data for public good gain increasing interest. Mos

Context: Systems of systems (SoS) are highly complex and are integrated on multiple levels (unit, component, system, system of systems). Many of the characteristics of SoS (such as operational and managerial independence, integration of system into system of systems, SoS comprised of complex systems) make their development and testing challenging. Contribution: This paper provides an understanding

Consumers are pushing for higher data rates to support more services that are introduced in mobile applications. As an example, a few years ago video-on-demand was only accessed through landlines, but today wireless devices are frequently used to stream video. To support this, more flexible network solutions have merged in 4G, introducing new technical problems to the mobile terminal. New techniqu