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Background: Prototyping is an established practice for user interface design and for requirements engineering within agile software development, even so there is a lack of theory on prototyping. Aims: The main research objective is to provide a means to categorise prototyping instances, in order to enable comparison and reflection of prototyping practices. Method: We have performed a systematic m
Large-scale software engineering is a collaborative effort where teams need to communicate to develop software products. Managers face the challenge of how to organise work to facilitate necessary communication between teams and individuals. This includes a range of decisions from distributing work over teams located in multiple buildings and sites, through work processes and tools for coordinatin
The use of radio signal for position tracking (positioning) and navigation has a long tradition. Most notably, global navigation satellite systems (GNSS) are now widely applied for civilian applications, ranging all the way from tracking of cargo containers to gaming. However, GNSS suffers from limited coverage in dense urban areas and indoors and also from a limited position accuracy, which rules
We use the received bit information rate (RBIR) to analyze the performance of multi-layer transmission when combined with hybrid automatic repeat request (HARQ). The different layers are obtained from ordinary Gray-coded M-QAM and used for transmitting log2(M) codewords in parallel, exploiting that the different bits in Gray-coded M-QAM have very different reliability. The performance is analyzed
Grammatical asymmetries in possessive constructions are overtly coded in about 18% of the world’s languages according to the World Atlas of Language Structures (Dryer & Haspelmath, 2013). What primarily motivates these grammatical asymmetries is controversial and has been at the crux of the “iconicity vs. frequency” debate (e.g. Croft, 2008; Haiman, 2008; Haspelmath, 2008). This paper contribu
Spatially distributed transmission points connected to the same source, known as distributed antenna systems, can improve system performance compared to single-link traditional systems. However, the anticipated gain depends heavily on the cross-correlation properties of the large-scale parameters (LSPs) of the different links. Usually, measured LSPs—except the large-scale fading
Non-Orthogonal Multiple Access (NOMA) for a multi-user single- input single-output (SISO) setup is studied in the power and the frequency domains simultaneously. The problem of sum-bandwidth minimization under perfect channel state information is solved for various combinations of rate requirements and user pairings. In this process, an iterative Tabu-search based algorithm is applied to avoid an
Non-Orthogonal Multiple Access (NOMA) is studied under statistical Channel State Information (CSI) and probabilistic constraints. Unlike the conventional power domain only NOMA, the definition of NOMA here considers both the power and the frequency domains simultaneously, where a flat power spectrum is assumed for each UE. This increases the capacity region when compared to the conventional definiti
For a pair of closely located and cooperating user equipments (UEs), a precoder is designed at the base station (BS) which considers the UE cooperation. The UEs collaborate over an out-of-band side-link with a finite capacity. The side-link may be used for interference cancellation (IC) or for relaying decoded symbols. The precoder has two parts, a cooperative part based on channel inversion and a
A scheme for exploiting cooperation in satellite receivers is proposed. The cooperation takes place through a capacity-constrained link, and we assume that a relay node quantizes its received signal and sends it to the destination node. We demonstrate its effectiveness with three different schemes on satellite channels with high-order APSK modulations. The first two schemes employ equidistant quan
The primary objective of this study is to compare the accuracy of two risk models, International Heart Transplantation Survival Algorithm (IHTSA), developed using deep learning technique, and Index for Mortality Prediction After Cardiac Transplantation (IMPACT), to predict survival after heart transplantation. Data from adult heart transplanted patients between January 1997 to December 2011 were c
The Theory of Characteristic Modes (TCM) has recently been shown to be beneficial in solving a wide variety of complex electromagnetic problems. However, there are still open issues in using TCM to analyze objects which consist of simple or complex media. Either a volume integral equation (VIE) or a surface integral equation (SIE) is required to solve for the characteristic modes of these objects.
In order to develop reliable communications links for high speed railway (HSR) systems, accurate models for the propagation channel are required. The radio channel properties in HSR scenarios are different from those in cellular scenarios not only due to the high velocity, but also due to the special construction elements and the type of surroundings along the train lines. This paper focuses on th
This article investigates digital predistortion (DPD) linearization of hybrid beamforming large-scale antenna transmitters. We propose a novel DPD processing and learning technique for an antenna sub-array, which utilizes a combined signal of the individual power amplifier (PA) outputs in conjunction with a decorrelation-based learning rule. In effect, the proposed approach results in minimizing t
Hidden antenna solutions for car roofs are of current interest to car manufacturers, to avoid having larger shark-fin based antenna systems to support growing number of wireless services. However, there are only a few studies in the literature on the integration of hidden antennas, particularly in relation to realistic roofs and propagation channels. This paper investigates the performance impact
The Theory of Characteristic Modes (TCM) offers a natural and systematic way to design Multiple-Input Multiple-Output (MIMO) antennas with high total efficiency and uncorrelated antenna patterns. In this paper, recent advances in the growing field of TCM-aided MIMO antenna design are reviewed. In particular, the focus is on the challenging problem of designing MIMO antennas for compact mobile term
Today's test methods used for verifying the performance and robustness of automotive applications using wireless communication are often based on fieldtrails, which are time consuming, costly, and not repeatable. Therefore, there is an urgent need for new verification methods that can be performed in lab environment, where the realistic radio propagation environment can be emulated. The telecom in
The focus of this thesis is on proposing and analyzing a powerful class of codes on graphs---with trellis constraints---that can simultaneously approach capacity and achieve very low error floor. In particular, we propose the concept of spatial coupling for turbo-like code (SC-TC) ensembles and investigate the impact of coupling on the performance of these codes. The main elements of this study ca
