Search results for "working"

Typical Aspects of the Microwave Noise Performance of HEMTs at Decreasing Temperatures

1996

In analog signal processing at microwave frequencies the noise performance of active devices is of fundamental importance for the accurate design of low-noise amplifiers. To this aim, the determination of the four noise parameters F O , Γ O (complex variable) and Rn has to be accomplished together with the usual scattering parameter measurements vs. frequency. In addition, the dependence of the device performance vs. temperature is of interest for circuit applications characterized by harsh environmental conditions. In this work the noise behavior of high electron mobility transistors has been investigated by means of measurements and modeling in the 2-18 GHz frequency range and as a functi…

The implications of the EU Labour law in Latvia

2013

Discrete wavelet transform implementation in Fourier domain for multidimensional signal

2002

Wavelet transforms are often calculated by using the Mallat algorithm. In this algorithm, a signal is decomposed by a cascade of filtering and downsampling operations. Computing time can be important but the filtering operations can be speeded up by using fast Fourier transform (FFT)-based convolutions. Since it is necessary to work in the Fourier domain when large filters are used, we present some results of Fourier-based optimization of the sampling operations. Acceleration can be obtained by expressing the samplings in the Fourier domain. The general equations of the down- and upsampling of digital multidimensional signals are given. It is shown that for special cases such as the separab…

A Robust Wrap Reduction Algorithm for Fringe Projection Profilometry and Applications in Magnetic Resonance Imaging.

2017

In this paper, we present an effective algorithm to reduce the number of wraps in a 2D phase signal provided as input. The technique is based on an accurate estimate of the fundamental frequency of a 2D complex signal with the phase given by the input, and the removal of a dependent additive term from the phase map. Unlike existing methods based on the discrete Fourier transform (DFT), the frequency is computed by using noise-robust estimates that are not restricted to integer values. Then, to deal with the problem of a non-integer shift in the frequency domain, an equivalent operation is carried out on the original phase signal. This consists of the subtraction of a tilted plane whose slop…

Improving the stability bound for the PPH nonlinear subdivision scheme for data coming from strictly convex functions

2021

Abstract Subdivision schemes are widely used in the generation of curves and surfaces, and therefore they are applied in a variety of interesting applications from geological reconstructions of unaccessible regions to cartoon film productions or car and ship manufacturing. In most cases dealing with a convexity preserving subdivision scheme is needed to accurately reproduce the required surfaces. Stability respect to the initial input data is also crucial in applications. The so called PPH nonlinear subdivision scheme is proven to be both convexity preserving and stable. The tighter the stability bound the better controlled is the final output error. In this article a more accurate stabilit…

Non-parametric spectrum cartography using adaptive radial basis functions

2017

This paper presents a framework for spectrum cartography based on the use of adaptive Gaussian radial basis functions (RBF) centered around a specific number of centroid locations, which are determined, jointly with the other RBF parameters, by the available measurement values at given sensor locations in a specific geographical area. The spectrum map is constructed non-parametrically as no prior knowledge about the transmitters is assumed. The received signal power at each location (over a given bandwidth and time period) is estimated as a weighted contribution from different RBF, in such a way that the both RBF parameters and the weights are jointly optimized using an alternating minimiza…

How to make head or tail of ‘bridging’ and ‘bonding’?: addressing the methodological ambiguity1

2008

A distinction has recently been proposed between bridging (or encompassing) and bonding (or inward-looking) social networks. However, existing theoretical contributions remain vague as to the fundamental meaning of both concepts. As a consequence, two distinct interpretations have developed alongside each other. In the present paper, we employ data on voluntary association membership in Flanders to empirically illustrate that both approaches can lead to substantially different outcomes and therefore appear to tap into different dimensions of bridging versus bonding. These findings underline the problematic nature of the current conceptual ambiguity. We conclude that should the bridging/bond…

Combining Inter-Subject Modeling with a Subject-Based Data Transformation to Improve Affect Recognition from EEG Signals

2019

Existing correlations between features extracted from Electroencephalography (EEG) signals and emotional aspects have motivated the development of a diversity of EEG-based affect detection methods. Both intra-subject and inter-subject approaches have been used in this context. Intra-subject approaches generally suffer from the small sample problem, and require the collection of exhaustive data for each new user before the detection system is usable. On the contrary, inter-subject models do not account for the personality and physiological influence of how the individual is feeling and expressing emotions. In this paper, we analyze both modeling approaches, using three public repositories. T…

A Comparative Analysis of Residual Block Alternatives for End-to-End Audio Classification

2020

Residual learning is known for being a learning framework that facilitates the training of very deep neural networks. Residual blocks or units are made up of a set of stacked layers, where the inputs are added back to their outputs with the aim of creating identity mappings. In practice, such identity mappings are accomplished by means of the so-called skip or shortcut connections. However, multiple implementation alternatives arise with respect to where such skip connections are applied within the set of stacked layers making up a residual block. While residual networks for image classification using convolutional neural networks (CNNs) have been widely discussed in the literature, their a…

Opportunities and challenges of the opening of the Arctic Ocean for Norway

2020

Abstract This chapter analyzes the potential opportunities and challenges associated with the opening of the Arctic Ocean for Norway. Climate change in the Arctic is opening up access to sea routes of the Arctic region, and this could boost trade and consequently result in a sharp increase in shipping traffic in Norway. Specifically, Northern Norway would become a focal point for port- and shipping-related activities. However, these opportunities can only be fully utilized if the various stakeholders involved are able to manage the challenges of the opening of the Arctic Ocean. Like opportunities, challenges also cover a range of spheres, including environmental pollution, ecological damage…