Sökresultat

Effective utilization of the spatial domain enhances the capacity of a mobile radio network. A common technique is to use sector antennas, where the sectors are formed by weighting the outputs from the antenna elements. This results in spatial domain selectivity, which significantly improves the signal-to-(noise and interference) ratio in the received signals. However, the operation of the sector

Subband adaptive filters have been proposed to speed up the convergence and to lower the computational complexity of time domain adaptive filters. However, subband processing causes signal degradations due to aliasing effects and amplitude distortions. This problem is unavoidable due to further filtering operations in subbands. In this paper, the problem of aliasing effect and amplitude distortion

This paper presents a new approach for multiple speaker DOA estimation using an array of microphones. The method relies on the fact that multiple independent speakers have a small overlap in the time-frequency domain, i.e. the individual signals are almost W-disjoint orthogonal. By introducing a time-frequency mask and by continuously tracking the set of time-frequency points corresponding to each

In many applications where speech separation and enhancement is of interest, e.g. conferencing systems, mobile phones and hearing aids, accurate speaker localization is important. This paper presents an alternative criteria for the well known steered response power with phase transform (SRP-PHAT) algorithm, in which the steered response relates to peaks in the fourth order cross cumulant, rather t

We present a variational formulation of the governing equations and introduce global indicators to describe the behavior of acoustofluidic devices driven at resonance frequencies by means of a piezoelectric transducer. The individuation of the correct Lagrangian densities for the different parts constituting the device (the piezo transducer, the silicon walls, the fluid-filled microchannel, and th

The ability to move safely between obstacles is critical for animals that fly rapidly through cluttered environments but surprisingly little is known about how they achieve this. Do they reactively avoid obstacles or do they instead fly towards the gaps between them? If they aim towards gaps, what information do they use to detect and fly through them? Here, we aim to answer these questions by pre

In the vehicular communication channels, the mobility of the receiver (RX) and the transmitter (TX) along with the movements of interacting objects in the propagation environment result in significant non-stationary channel fading. The channel impulse response exhibits not just significant delay- and Doppler spreads, but also the delay- and Doppler spreads themselves are changing over the time- an

Objective: The atrioventricular (AV) node plays a central role in atrial fibrillation (AF) as it influences the conduction of impulses from the atria into the ventricles. In the present paper, the statistical dual pathway AV node model, previously introduced by us, is modified so that it accounts for atrial impulse pathway switching even if the preceding impulse did not cause a ventricular activat

The purpose of this work is to develop and implement a simple and robust preservation technology that can enhance food and economic security and thereby improve the lives of people in developing countries. The technique under development is termed “solar assisted pervaporation (SAP)”. It is a sustainable technology whereby fruit juices or purées are concentrated using reusable pouches made of “bre

In this study, we systematically assess the spatial variability in carbon and nitrogen balance simulations related to the choice of global circulation models (GCMs), representative concentration pathways (RCPs), spatial resolutions, and the downscaling methods used as calculated with LPJ-GUESS. We employed a complete factorial design and performed 24 simulations for Europe with different climate i

In this work we implement features for IEEE 802.11ac in the NS-3 simulator, in particular wider channels and bit-error calculations for higher modulation coding schemes. We also implement four wireless LAN deployment scenarios from the 802.11ax working group scenario document, and evaluate their performance under different operating conditions. Our simulation results demonstrate that many nodes in

In the quest for deciphering disease-associated biomarkers, high-performing tools for multiplexed protein expression profiling of crude clinical samples will be crucial. Affinity proteomics, mainly represented by antibody-based microarrays, have during recent years been established as a proteomic tool providing unique opportunities for parallelized protein expression profiling. But despite the pro

The second generation (2G) cellular networks are the current workhorse for machine-to-machine (M2M) communications. Diversity in 2G devices can be present both in form of multiple receive branches and blind repetitions. In presence of diversity, intersymbol interference (ISI) equalization and co-channel interference (CCI) suppression are usually very complex. In this paper, we consider the improve

Expression of antibodies inside cells has been used successfully to ablate protein function. This finding suggests that the technology should have an impact on disease treatment and in functional genomics where proteins of unknown function are predicted from genomic sequences. A major hindrance is the paucity of antibodies that function in eukaryotic cells, presumably because the antibodies fold i

Background: With a yearly incidence of 56 per 100,000 inhabitants, colorectal cancer (CRC) is one of the most common malignancies in the Western world, representing the third leading cause of cancer-related mortality. Within three years after the diagnosis of CRC, 29% of patients will have developed liver metastases. Liver resection is a possibly curative treatment, and several preoperative strate

PURPOSE: The feasibility of hyperpolarized 129Xe for fast MR angiography (MRA) was evaluated using the echo-planar imaging (EPI) technique.MATERIAL AND METHODS: Hyperpolarized Xe gas was dissolved in ethanol, a carrier agent with high solubility for Xe (Ostwald solubility coefficient 2.5) and long relaxation times. The dissolved Xe was injected as a bolus into a flow phantom where the mean flow ve

The measurement of absorbed dose distributions using dosemeter gel and magnetic resonance imaging (MRI) in a standard geometry has been investigated. Absorbed depth-dose curves and profiles measured with this new technique show good agreement with corresponding measurements using diodes. This was proven in a 60Co beam as well as an electron beam. The dosemeter gel is made of agarose and ferrous su