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We study the nature of the [Ti II] and [Ni II] emission from the so-called strontium filament found in the ejecta of eta Carinae. To this purpose, we employ multilevel models of the Ti II and Ni II systems, which are used to investigate the physical condition of the filament and the excitation mechanisms of the observed lines. For the Ti II ion, for which no atomic data were previously available,

OBJECTIVE: Recent studies have found an increased risk for both anxiety disorder and attention-deficit hyperactivity disorder (ADHD) in the adult relatives of children with ADHD in comparison with adult relatives of normal controls. Such findings may account for the high rates of comorbid anxiety found in children with ADHD, and they suggest a relationship between the two disorders. However, addit

The amount of data in large-scale software engineering contexts continues to grow and challenges efficiency of software engineering efforts. At the same time, information related to requirements plays a vital role in the success of software products and projects. To face the current challenges in software engineering information management, software companies need to reconsider the current models

PLL (Phase Locked Loop) based frequency synthesizers are widely used in the wireless communication field. This paper puts focus on the design and implementation of a 60dB SNR (Signal to Noise Ratio) FM transmitter, which realizes direct frequency modulation of audio signal by utilizing a carrier frequency ranging from 78MHz to 108MHz, with a 100 kHz channel selection resolution. Fabricated in stan

In this paper we analyze the small-scale fading statistics for vehicle-to-vehicle (V2V) communications in a typical open sub-urban street crossing. The two cars approach the crossing from two different streets and the channel conditions vary from non line-of sight (NLOS) to line-of-sight (LOS). The small-scale fading of the first delay bin is Ricean distributed with a time-varying K-factor. The la

Abstract in UndeterminedAs standards and regulatory codes are issued by third party organizations and committees, the project organization can neither control the content of all standards that the projects should adhere to, nor negotiate or make changes to them that can make the project development easier. Moreover, large infrastructure projects require compliance with hundreds of standards of reg

In this paper, we study random puncturing of protograph-based spatially coupled low-density parity-check (SC- LDPC) code ensembles. We show that, with respect to iterative decoding threshold, the strength and suitability of an LDPC code ensemble for random puncturing over the binary erasure channel (BEC) is completely determined by a single constant that depends only on the rate and iterative deco

We consider an optimization problem of joint link rate assignment and transmission scheduling in wireless mesh networks. We assume that each radio link uses (when active) one selected link-dependent modulation and coding scheme. For finding an exact optimum, the problem requires a complicated branch-and-price algorithm that becomes excessively time consuming for networks of practical size. Therefo

The total transmission bandwidth and component carrier aggregation proposed by LTE-Advanced, sets a new challenge to the design of terminals. This article presents a way to assure terminals cope with the large bandwidth in an efficient manner. Various filtering methods are explored showing that an SDR architecture, such as ADRES (Architecture for Dynamically Reconfigurable Embedded Systems), is su

This work focuses on the design of SC-LDPC codes for transmission over non-ergodic, block-fading channels. Our main contribution is an algorithm, allowing to start from a (J,K )-regular, uncoupled LDPC ensemble, from which one can recursively build up a protograph-based SC-LDPC ensemble having any target diversity order d. The diversity order is achieved assuming a low-complexity iterative decodin

Background: There is a need for ecient regression testing in most software development organizations. Often the proposed solutions involve automation. However, despite this being a well researched area, research results are rarely applied in industrial practice. Aim: In this paper we aim to bridge the gap between research and practice by providing examples of how evidence-based regression testing

In this paper a non-line-of-sight (NLOS) path-loss and fading model developed for vehicle-to-vehicle (V2V) communication at 5:9 GHz is validated with independent and realistic measurement data. The reference NLOS model is claimed to be flexible and of low complexity, and incorporates specific geometric aspects in a closed-form expression.We validated the accuracy of the model with the help of real

An increasing demand from e.g. real-time multimedia applications (IPTV, OTT) adds strains on especially DSL based access links. In this paper we argue why it is important to study DSL link impairments and their impact on QoS parameters on higher layers. We discuss the need for establishing methods for quality of service estimation with cross layer techniques and present some initial results.

Pattern reconfigurability is a desirable feature of mobile handset antennas, as it enables the antennas to adapt to non-stationary propagation environments. However, it is difficult to vary the radiation pattern of a handset antenna at frequencies below 1 GHz because the entire chassis commonly acts as the main radiator. Hence, designing pattern reconfigurability based on the antenna element (seco

The pervasive use and insatiable demand for high-performance wireless devices globally are driving the development of new communication technologies and standards. In this chapter, we present advancements in the area of terminal antenna systems and describe how they play a major role in enabling strict performance requirements to be met in future systems. As opposed to conventional systems that do

Context: The authors wanted to assess whether the quality of published human-centric software engineering experiments was improving. This required a reliable means of assessing the quality of such experiments. Aims: The aims of the study were to confirm the usability of a quality evaluation checklist, determine how many reviewers were needed per paper that reports an experiment, and specify an ap