Search results for "signal processing"
showing 10 items of 2451 documents
Dependence of the energy of water molecules in clusters upon hydrogen bonds: a Hirshfeld study
2008
Abstract: The energy of water clusters, containing up to 20 water molecules, are partitioned into molecular contributions using the Hirshfeld method at the DFT level. The molecular energies are analyzed with respect to the hydrogen bonding network in the clusters.
Input-Output Finite-Time Stability of Discrete-Time Impulsive Switched Linear Systems with State Delays
2013
Published version of an article in the journal: Circuits, Systems, and Signal Processing. Also available from the publisher at: http://dx.doi.org/10.1007/s00034-013-9610-7 This paper is concerned with the problem of input-output finite-time stability (IO-FTS) for discrete impulsive switched systems with state delays. Sufficient conditions are presented for the existence of IO-FTS for such systems under the cases of certain switching, arbitrary switching, and uncertain switching. All the obtained results are formulated in a set of linear matrix inequalities (LMIs). Two numerical examples are given to illustrate the effectiveness of the proposed results.
Precision luminosity measurements at LHCb
2014
Measuring cross-sections at the LHC requires the luminosity to be determined accurately at each centre-of-mass energy $\sqrt{s}$. In this paper results are reported from the luminosity calibrations carried out at the LHC interaction point 8 with the LHCb detector for $\sqrt{s}$ = 2.76, 7 and 8 TeV (proton-proton collisions) and for $\sqrt{s_{NN}}$ = 5 TeV (proton-lead collisions). Both the "van der Meer scan" and "beam-gas imaging" luminosity calibration methods were employed. It is observed that the beam density profile cannot always be described by a function that is factorizable in the two transverse coordinates. The introduction of a two-dimensional description of the beams improves sig…
Digital slicing of 3D scenes by Fourier filtering of integral images
2008
We present a novel technique to extract depth information from 3D scenes recorded using an Integral Imaging system. The technique exploits the periodic structure of the recorded integral image to implement a Fourier-domain filtering algorithm. A proper projection of the filtered integral image permits reconstruction of different planes that constitute the 3D scene. The main feature of our method is that the Fourier-domain filtering allows the reduction of out-of-focus information, providing the InI system with real optical sectioning capacity.
Acoustic rendering of particle-based simulation of liquids in motion
2009
In interaction and interface design, the representation of continuous processes often uses liquid metaphors, such as dripping or streaming. When an auditory display of such processes is required, an approach to sound-synthesis based on the physics of liquids in motion would be the most convincing, especially when real-time interaction is into play. In order to bridge the complexity of fluid-dynamic simulations with the needs of interactive sonification, we propose a multi-rate sound synthesis of liquid phenomena. Low-rate smoothed-particle hydrodynamics is used to model liquids in motion and to trigger sound-emitting events. Such events, such as solid-liquid collision, or bubble formation, …
AI-IoT Platform for Blind Estimation of Room Acoustic Parameters Based on Deep Neural Networks
2023
Room acoustical parameters have been widely used to describe sound perception in indoor environments, such as concert halls, conference rooms, etc. Many of them have been standardized and often have a high computational demand. With the increasing presence of deep learning approaches in automatic monitoring systems, wireless acoustic sensor networks (WASNs) offer great potential to facilitate the estimation of such parameters. In this scenario, Convolutional Neural Networks (CNNs) offer significant reductions in the computational requirements for in-node parameter predictions, enabling the so-called Artificial Intelligence-Internet of Things (AI-IoT). In this paper, we describe the design a…
Filtering out intersymbol interference in spread-spectrum communication systems
1979
In this letter the transfer characteristic of the optimum filter suitable for eliminating intersymbol interference in pseudo-noise spread-spectrum communication systems is determined. Such a characteristic is independent of the code sequence employed.
Smart Grid Security: A new Approach to Detect Intruders in a Smart Grid Neighborhood Area Network
2016
International audience; In this paper, we propose an efficient and lightweight attack detection mechanism for a smart grid Neighborhood Area Network (NAN) that combine between distributed and centralized intrusion detection. A NAN includes the customers' appliances, smart meters and collectors. The smart meters measure the power consumption of each appliance and the collectors aggregate the measures and forward them to the control center for analysis. Intrusion Detection System (IDS) agents, proposed in our framework, run in a distributed fashion at smart meters level and in a centralized fashion at collector and control center nodes. A combination between a rule-based detection and a learn…
Boolean-controlled systems via receding horizon and linear programing
2009
We consider dynamic systems controlled by boolean signals or decisions. We show that in a number of cases, the receding horizon formulation of the control problem can be solved via linear programing by relaxing the binary constraints on the control. The idea behind our approach is conceptually easy: a feasible control can be forced by imposing that the boolean signal is set to one at least one time over the horizon. We translate this idea into constraints on the controls and analyze the polyhedron of all feasible controls. We specialize the approach to the stabilizability of switched and impulsively controlled systems.
Inverse Scattering Solutions with Applications to Electromagnetic Signal Processing
2009
When a signal is recorded that has been physically generated by some scattering process (the interaction of electromagnetic, acoustic or elastic waves with inhomogeneous materials, for example), the ‘standard model’ for the signal (i.e. information content convolved with a characteristic Impulse Response Function) is usually based on a single scattering approximation. An additive noise term is introduced into the model to take into account a range of non-deterministic factors including multiple scattering that, along with electronic noise and other background noise sources, is assumed to be relatively weak. Thus, the standard model is based on a ‘weak field condition’ and the inverse scatte…