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This thesis is based on five papers (A-E) treating estimation methods for unbounded densities, random fields generated by Lévy processes, behavior of Lévy processes at level crossings, and a Markov random field mixtures of multivariate Gaussian fields. In Paper A we propose an estimator of the location parameter for a density that is unbounded at the mode. The estimator maximizes a modified lik
In this paper, we study a flexible routing strategy for demand protection and a corresponding optimization problem for networks that permanently experience fluctuations of the capacity available on their links. This is an important and novel topic as limited link availability is a fundamental feature of wireless networks; yet majority of work in survivable network design is restricted to total fai
Although the research on the design of heterogeneous concurrent systems has a long and rich history, a unified design methodology and tool support have not emerged so far. Therefore, the creation of such systems remains a difficult, time-consuming and error-prone process. The absence of principled support for system evaluation and optimization at high level of abstraction makes the quality of the
Quality requirements complement functional requirements with information on the target quality levels of software functions or emergent system quality aspects. In release planning the allocation of development effort in further investments into product enhancements, new or enhanced functions are competing with quality improvements for limited resources. When setting balanced quality targets for de
We introduce successive cancellation (SC) decoding of product codes (PCs) with single parity-check (SPC) component codes. Recursive formulas are derived, which resemble the SC decoding algorithm of polar codes. We analyze the error probability of SPC-PCs over the binary erasure channel under SC decoding. A bridge with the analysis of PCs introduced by Elias in 1954 is also established. Furthermore
This thesis focuses on algorithms and proofs of concepts in the area of wireless systems operating with a large number of antennas, especially at the base station side.The first studied topic concerns the design and implementation of massive multiple-input multiple-output (MIMO) testbeds, primarily for communications. This is an entirely new engineering challenge on its own, due to the unprecedent
During the last few years most work done on the task of image segmentation has been focused on deep learning and Convolutional Neural Networks (CNNs) in particular. CNNs are powerful for modeling complex connections between input and output data but lack the ability to directly model dependent output structures, for instance, enforcing properties such as smoothness and coherence. This drawback mot
A fully automatic system for abdominal organ segmentation is presented. As a first step, an organ localization is obtained via a robust and efficient feature registration method where the center of the organ is estimated together with a region of interest surrounding the center. Then, a convolutional neural network performing voxelwise classification is applied. The convolutional neural network co
Background. Search and selection of primary studies in Systematic Literature Reviews (SLR) is labour intensive, and hard to replicate and update. Aims. We explore a machine learning approach to support semi-automated search and selection in SLRs to address these weaknesses. Method. We 1) train a classi er on an initial set of papers, 2) extend this set of papers by automated search and snowballing
Abundant data is the key to successful machine learning. However, supervised learning requires annotated data that are often hard to obtain. In a classification task with limited resources, Active Learning (AL) promises to guide annotators to examples that bring the most value for a classifier. AL can be successfully combined with self-training, i.e., extending a training set with the unlabelled e
In sensor network applications with low traffic intensity, idle channel listening is one of the main sources of energy waste. The use of a dedicated low-power wake-up receiver (WRx), which utilizes duty-cycled channel listening, can significantly reduce the idle listening energy cost. Extreme low-power design typically leads to performance losses, indirectly increasing energy costs. Striking the r
We consider designing demodulators for linear vector channels that use reduced-size trellis descriptions for the received signal. We assume an iterative receiver and use interference cancellation (IC) with soft-information provided by an outer decoder to mitigate the signal part that is not covered by a reduced-size trellis description. In order to reach a trellis description, a linear filter is a
We consider the potential for positioning with a system where antenna arrays are deployed as a large intelligent surface (LIS), which is a newly proposed concept beyond massive multi-input multi-output (MIMO) where future man-made structures are electronically active with integrated electronics and wireless communication making the entire environment "intelligent". In a first step, we derive Fishe
In this paper, we consider the potential of data-transmission in a system with a massive number of radiating and sensing elements, thought of as a contiguous surface of electromagnetically active material. We refer to this as a Large Intelligent Surface (LIS). The "LIS" is a newly proposed concept, which conceptually goes beyond contemporary massive MIMO technology, and arises from our vision of a
In this paper, we introduce the concept of spatially coupled turbo-like codes (SC-TCs) as the spatial coupling of a number of turbo-like code ensembles. In particular, we consider the spatial coupling of parallel concatenated codes, introduced by Berrou et al., and that of serially concatenated codes (SCCs), introduced by Benedetto et al. Furthermore, we propose two extensions of braided convoluti
Hsu–Kasami–Chien (HKC) are a class of cyclic codes that can correct either burst or random errors. This paper studies the maximum burst-correcting capability of HKC codes. A necessary and sufficient condition for a b- burst-correcting cyclic HKC code is given and simplified as a generalized one for Fire codes. An upper bound on the burstcorrecting capability of HKC codes is derived, which improves
The effect of a user’s body on channel characteristics for single user downlink transmission in an urban scenario for the 5th generation (5G) systems is investigated with ray-tracing at 15 GHz and 28 GHz. Three different designs of user equipment (UE) antennas are fabricated and integrated into a mobile phone prototype, and their 3D radiation patterns are measured both with and without
In this letter, the fading statistics of wireless channels in high-speed railway cutting scenarios are characterized based on measurements. A multiple scattering model called second-order scattering fading (SOSF) is used to model the small-scale fading considering the influence of cuttings and bridges. The SOSF model can offer the possibility of analytical estimation for different fading severitie
Radio-based localization has the potential to provide centimeter-level position information. In this paper we apply joint probabilistic data association to multipath-assisted simultaneous localization and mapping (SLAM) for this purpose. In multipath-assisted localization, position-related information in multipath components (MPCs) is exploited to increase the accuracy and robustness of indoor tra
Massive MIMO (MaMIMO) is a key technology for 5G wireless communication, enabling large increase in both spectral and energy efficiency at the same time. Before it can be deployed, it is important to find efficient implementation strategies. Because of the many antennas, an essential part of decreasing complexity, and further improving energy efficiency, is optimization of the digital signal proce
