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Successful development of software systems involves efficient navigation among software artifacts. However, as artifacts continuously are produced and modified, engineers are typically plagued by challenging information landscapes. One state-of-practice approach to structure information is to establish trace links between artifacts, a practice that is also enforced by several development standards

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

Excitation of the chassis enables single-antenna terminals to achieve good bandwidth and radiation performance, due to the entire chassis being utilized as the main radiator. In contrast, the same chassis excitation phenomenon complicates the design of multiple antennas for MIMO applications, since the same characteristic mode of the chassis may be effectively excited by more than one antenna, lea

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

The 60 GHz band is very promising for high data rate (>1 Gb/s) wireless systems operating at short ranges. However, due to the short wavelengths in this frequency band, the shadowing effects cuased by human bodies and furniture are severe and need to be modeled properly. In this paper, we present an experimental, measurement-based characterization of the reflection and shadowing effects in the 60

Context: Software product lines (SPL) are used in industry to achieve more efficient software development. However, the testing side of SPL is underdeveloped. Objective: This study aims at surveying existing research on SPL testing in order to identify useful approaches and needs for future research. Method: A systematic mapping study is launched to find as much literature as possible, and the 64

The post-failure convergence of shortest path routing (SPR) protocols used in IP networks can be too slow to meet the restrictive requirements (i.e. maximum allowable delay, jitter, etc.) of the multimedia services and therefore new protection/restoration mechanisms combined with IP routing are of interest. The article addresses the optimization of three potential rerouting mechanisms based on the

In this paper we establish a geometry-based stochastic ultra-wideband channel model for outdoor infostations scenarios. We statistically describe the location and strength of clusters of scatterers, as well as the shape and width of visibility and shadowing regions. We also separately model diffuse radiation (which cannot be explained by the scatterer components), and show that its fading statisti

Effective requirements engineering (RE) can support efficient development of successful products. However, assessing and improving how RE supports its context, i.e. the development life cycle, is non-trivial since many different roles and factors are involved over a long period of time. Project retrospectives may support project teams in reflecting on how requirements are agreed upon and communica

Background: The popularity of the open source software development in the last decade, has brought about an increased interest from the industry on how to use open source components, participate in the open source community, build business models around this type of software development, and learn more about open source development methodologies. Aim: The aim of this study is to review research ca

We consider a window decoding scheme for Braided Convolutional Codes (BCCs) based on the BCJR algorithm. We describe the principle of this decoding scheme and show that BCCs with window decoding exhibit excellent performance. The tradeoff between performance and decoding latency is examined and, to reduce decoding complexity, both uniform and nonuniform message passing schedules within the decodin

This paper presents an efficient technique to enhance the isolation between two closely spaced PIFAs for MIMO mobile terminals. The proposed decoupling method is based on a T-shape slot impedance transformer and it enables an inter-PIFA spacing of 1 mm to be achieved. The 10 dB impedance bandwidth and 20 dB isolation bandwidth cover the 2.4 GHz WLAN band (2.4-2.48 GHz), with a maximum isolation of

Data volumes in communication networks increase rapidly. Further, usage of social network applications is very wide spread among users, and among these applications, Facebook is the most popular. In this paper, we analyse user demands patterns and content popularity of Facebook generated traffic. The data comes from residential users in two metropolitan access networks in Sweden, and we analyse mo