Automatic Classification of Anomalous ECG Heartbeats from Samples Acquired by Compressed Sensing.

In this paper, a method for the classification of anomalous heartbeats from compressed ECG signals is proposed. The method operating on signals acquired by compressed sensing is based on a feature extraction stage consisting of the evaluation of the Discrete Cosine Transform (DCT) coefficients of the compressed signal and a classification stage performed by means of a set of k-nearest neighbor ensemble classifiers. The method was preliminarily tested on five classes of anomalous heartbeats, and it achieved a classification accuracy of 99.

The Uncertainty Assessment by the Monte Carlo Analysis of NDVI Measurements Based on Multispectral UAV Imagery.

This paper proposes a workflow to assess the uncertainty of the Normalized Difference Vegetation Index (NDVI), a critical index used in precision agriculture to determine plant health. From a metrological perspective, it is crucial to evaluate the quality of vegetation indices, which are usually obtained by processing multispectral images for measuring vegetation, soil, and environmental parameters. For this reason, it is important to assess how the NVDI measurement is affected by the camera characteristics, light environmental conditions, as well as atmospheric and seasonal/weather conditions.

Sensors and Measurements for UAV Safety: An Overview.

Unmanned aerial vehicles' (UAVs) safety has gained great research interest due to the increase in the number of UAVs in circulation and their applications, which has inevitably also led to an increase in the number of accidents in which these vehicles are involved. The paper presents a classification of UAV safety solutions that can be found in the scientific literature, putting in evidence the fundamental and critical role of sensors and measurements in the field. Proposals from research on each proposed class concerning flight test procedures, in-flight solutions including soft propeller use, fault and damage detection, collision avoidance and safe landing, as well as ground solution including testing and injury and damage quantification measurements are discussed.

A Dictionary Optimization Method for Reconstruction of ECG Signals after Compressed Sensing.

This paper presents a new approach for the optimization of a dictionary used in ECG signal compression and reconstruction systems, based on Compressed Sensing (CS). Alternatively to fully data driven methods, which learn the dictionary from the training data, the proposed approach uses an over complete wavelet dictionary, which is then reduced by means of a training phase. Moreover, the alignment of the frames according to the position of the R-peak is proposed, such that the dictionary optimization can exploit the different scaling features of the ECG waves.

Resolving voltage-time dilemma using an atomic-scale lever of subpicosecond electron-phonon interaction.

Nanoelectronic memory based on trapped charge need to be small and fast, but fundamentally it faces a voltage-time dilemma because the requirement of a high-energy barrier for data retention under zero/low electrical stimuli is incompatible with the demand of a low-energy barrier for fast switching under a modest programming voltage. One solution is to embed an atomic-level lever of localized electron-phonon interaction to autonomously reconfigure trap-site's barrier in accordance to the electron-occupancy of the site. Here we demonstrate an atomically levered resistance-switching memory built on locally flexible amorphous nanometallic thin films: charge detrapping can be triggered by a mechanical force, the fastest one being a plasmonic Lorentz force induced by a nearby electron or positron bunch passing in 10(-13) s.

Elementary excitations at magnetic surfaces and their spin dependence.

The elementary surface excitations are studied by spin-polarized electron energy loss spectroscopy on a prototype oxide surface [an oxygen passivated Fe(001)-p(1×1) surface], where the various excitations coexist. For the first time, the surface phonons and magnons are measured simultaneously and are distinguished based on their different spin nature. The dispersion relation of all excitations is probed over the entire Brillouin zone.

Magnons in a ferromagnetic monolayer.

We report the first observation of high wave vector magnon excitations in a ferromagnetic monolayer. Using spin-polarized electron energy loss spectroscopy, we observed the magnon dispersion in one atomic layer (ML) of Fe on W(110) at 120 K. The magnon energies are small in comparison to the bulk and surface Fe(110) excitations.

Large wave vector spin waves and dispersion in two monolayer fe on w(110).

We present the first surface spin-wave (SW) dispersion measurements up to the surface Brillouin zone boundary of a two monolayer Fe film on W(110) by using spin-polarized electron energy loss spectroscopy. Pronounced features of SW peaks are observed in the spectra at room temperature. We found that the SW energies in the Fe film are strongly reduced compared to spin waves in bulk Fe and to theoretical predictions.

Dissipation of spin angular momentum in magnetic switching.

Applying one ultrashort magnetic field pulse, we observe up to 10 precessional switches of the magnetization direction in single crystalline Fe films of 10 and 15 atomic layers. We find that the rate at which angular momentum is dissipated in uniform large angle spin precession increases with time and film thickness, surpassing the intrinsic ferromagnetic resonance spin lattice relaxation of Fe by nearly an order of magnitude.

The ultimate speed of magnetic switching in granular recording media.

In magnetic memory devices, logical bits are recorded by selectively setting the magnetization vector of individual magnetic domains either 'up' or 'down'. In such devices, the fastest and most efficient recording method involves precessional switching: when a magnetic field B(p) is applied as a write pulse over a period tau, the magnetization vector precesses about the field until B(p)tau reaches the threshold value at which switching occurs. Increasing the amplitude of the write pulse B(p) might therefore substantially shorten the required switching time tau and allow for faster magnetic recording.