Search results for: OSCILLATING TRIBOMETRY
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Grazing bifurcation and chaotic oscillations of vibro-impact systems with one degree of freedom
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Central Vagotonic Effects of Atropine Modulate Spectral Oscillations of Sympathetic Nerve Activity
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Analog fault signature based on sigma-delta modulation and oscillation-test methodology.
PublicationW artykule dokonano przeglądu prac z zakresu testowania układów elektronicznych metodą oscylacyjną. Wskazując na niedostatki aktualnie stosowanej techniki testowania oscylacyjnego zaproponowano nową sygnaturę uszkodzeń dla układów analogowych. Proponowany parametr diagnostyczny jest wydobywany z odpowiedzi czasowej oscylatora testującego, w układzie złożonym z detektora szczytowego, modulatora sigma-delta oraz licznika rewersyjnego....
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Model and simulation tests of a squirrel-cage induction motor with oscillation of air gap
PublicationPrzedstawiono model matematyczny silnika, który pozwala na wprowadzanie ekscentryczności wirnika. Zaprezentowano obliczone widma prądu z wprowadzoną oscylacją wirnika, co z pewnym przybliżeniem odpowiada uszkodzeniu łożyska. Rezultaty symulacji pozwalają na określenie zależności pomiędzy oscylacją szczeliny powietrznej i składowych w widmie prądu.
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Friction-Induced Oscillations of a Non-Asbestos Organic Pin Sliding on a Steel Disc
PublicationFriction-induced oscillations result in deterioration of performance of disc brakes and are generally undesired. We conduct experimental study of friction-induced oscillations in a non-asbestos organic material / steel pair used in disc brakes of motor vehicles. The tests are done by use of a pin-on-disc machine which has the pin sample supported on a deformable beam. The adjustable friction parameters are the disc velocity, contact...
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Coupling between Blood Pressure and Subarachnoid Space Width Oscillations during Slow Breathing
PublicationThe precise mechanisms connecting the cardiovascular system and the cerebrospinal fluid (CSF) are not well understood in detail. This paper investigates the couplings between the cardiac and respiratory components, as extracted from blood pressure (BP) signals and oscillations of the subarachnoid space width (SAS), collected during slow ventilation and ventilation against inspiration resistance. The experiment was performed on...
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Ripple oscillations in the left temporal neocortex are associated with impaired verbal episodic memory encoding
PublicationBACKGROUND: We sought to determine if ripple oscillations (80-120 Hz), detected in intracranial electroencephalogram (iEEG) recordings of patients with epilepsy, correlate with an enhancement or disruption of verbal episodic memory encoding. METHODS: We defined ripple and spike events in depth iEEG recordings during list learning in 107 patients with focal epilepsy. We used logistic regression models (LRMs) to investigate the...
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On the mechanism of oscillations in three-phase system containing coationc surfactant and nitrobenzene liquid membrane
PublicationObserwuje się oscylacje różnicy potencjału elektochemicznego między fazami wodnymi oscylatora zawierającego bromek heksadecylotrimetyloamoniowy. Ta różnica potencjału składa sie z potencjałów na granicach faz między membraną a fazą wodną donorową oraz membraną a fazą wodną akceptorową. Wykazano, że oscylacje zachodzą na granicy fazy akceptorowej i membrany. Są one spowodowane procesami adsorpcji/desorpcji pary jonowej surfaktantu...
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Wavelet transform analysis to assess oscillations in pial artery pulsation at the human cardiac frequency
PublicationPial artery adjustments to changes in blood pressure (BP)may last only seconds in humans. Using a novelmethod called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) in humans, we aimed to assess the relationship between spontaneous oscillations in BP and cc-TQ at frequencies between 0.5 Hz and 5 Hz. We hypothesized that analysis of...
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Wild oscillations in a nonlinear neuron model with resets: (I) Bursting, spike-adding and chaos
PublicationIn a series of two papers, we investigate the mechanisms by which complex oscillations are generated in a class of nonlinear dynamical systems with resets modeling the voltage and adaptation of neurons. This first paper presents mathematical analysis showing that the system can support bursts of any period as a function of model parameters, and that these are organized in a period-incrementing structure. In continuous dynamical...
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High-quality Experiment Dedicated to microGravity Exploration, Heat Flow and Oscillation Measurement from Gdańsk
PublicationIn this paper we propose HEDGEHOG (High-quality Experiment Dedicated to microGravity Exploration, Heat flow and Oscillation measurement from Gdańsk) REXUS experiment to investigate vibrational and heat flow phenomena during the whole (ascent, microgravity phase, descent and recovery) flight of a sounding rocket. First, a proposed system of cantilever beams is discussed to study dynamic behaviour of dummy payload. Dimensioning has...
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Mild poikilocapnic hypoxia increases very low frequency haemoglobin oxygenation oscillations in prefrontal cortex
PublicationBackground: The aim of the study was to investigate the effect of mild cerebral hypoxia on haemoglobin oxygenation(HbO2), cerebrospinal fluid dynamics and cardiovascular physiology. To achieve this goal, four signals were recorded simultaneously: blood pressure, heart rate / electrocardiogram, HbO2 from right hemisphere and changes of subarachnoid space (SAS) width from left hemisphere. Signals were registered from 30 healthy,...
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Electrochemical oscillations and bistability during anodic dissolution of vanadium electrode in acidic media—part I. Experiment
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Theory versus experiment for vacuum Rabi oscillations in lossy cavities. II. Direct test of uniqueness of vacuum
PublicationThe paper continues the analysis of vacuum Rabi oscillations we started in part I [Phys. Rev. A 79, 033836 (2009)]. Here we concentrate on experimental consequences for cavity QED of two different classes of representations of harmonic-oscillator Lie algebras. The zero-temperature master equation, derived in part I for irreducible representations of the algebra, is reformulated in a reducible representation that models electromagnetic...
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Electrochemical oscillations and bistability during anodic dissolution of vanadium elektrode in acidic media. part 1. Experiment
PublicationDynamiczne niestabilności, oscylacje prądowe i bistabilność obserwowane były podczas anodowego roztwarzania elektrody wanadowej w trakcie badań wykorzystujących techniki stało i zmienno prądowe. Analizowany był wpływ warunków eksperymentalnych jak: stężenia kwasu, temperatury itd. Badania pozwoliły stworzyć diagramy przedstawiające regiony występowania oscylacji i bistabilności.
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Coupling of Blood Pressure and Subarachnoid Space Oscillations at Cardiac Frequency Evoked by Handgrip and Cold Tests: A Bispectral Analysis
PublicationThe aim of the study was to assess blood pressure–subarachnoid space (BP–SAS) width coupling properties using time–frequency bispectral analysis based on wavelet transforms during handgrip and cold tests. The experiments were performed on a group of 16 healthy subjects (F/M; 7/9) of the mean age 27.2 ± 6.8 years and body mass index of 23.8 ± 4.1 kg/m². The sequence of challenges was first handgrip and then cold test. The handgrip...
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Weak localization competes with the quantum oscillations in a natural electronic superlattice: The case of Na1.5(PO2)4(WO3)20
PublicationWe report an investigation of the combined structural and electronic properties of the bronze Na1.5(PO2)4(WO3)20. Its low-dimensional structure and possible large reconstruction of the Fermi surface due to charge density wave instability make this bulk material a natural superlattice with a reduced number of carriers and Fermi energy. Signatures of multilayered two-dimensional (2D) electron weak localization are consequently reported,...
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Combined Single Neuron Unit Activity and Local Field Potential Oscillations in a Human Visual Recognition Memory Task
PublicationGOAL: Activities of neuronal networks range from action potential firing of individual neurons, coordinated oscillations of local neuronal assemblies, and distributed neural populations. Here, we describe recordings using hybrid electrodes, containing both micro- and clinical macroelectrodes, to simultaneously sample both large-scale network oscillations and single neuron spiking activity in the medial temporal lobe structures...
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Acute hypoxia diminishes the relationship between blood pressure and subarachnoid space width oscillations at the human cardiac frequency
PublicationAcute hypoxia exerts strong effects on the cardiovascular system. Heart-generated pulsatile cerebrospinal fluid motion is recognised as a key factor ensuring brain homeostasis. We aimed to assess changes in heart-generated coupling between blood pressure and subarachnoid space width oscillations during hypoxic exposure.
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Increased inspiratory resistance affects the dynamic relationship between blood pressure changes and subarachnoid space width oscillations
PublicationBackground and objective Respiration is known to affect cerebrospinal fluid (CSF) movement. We hypothesised that increased inspiratory resistance would affect the dynamic relationship between blood pressure (BP) changes and subarachnoid space width (SAS) oscillations. Methods Experiments were performed in a group of 20 healthy volunteers undergoing controlled intermittent Mueller Manoeuvres (the key characteristic of the procedure...
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AN ATTEMPT AT IDENTIFYING THE INFLUENCE OF TEST HEAD ASSEMBLY STIFFNESS ON THE RESULTS OF A TRIBOLOGICAL EXPERIMENT CONDUCTED UNDER MICRO-OSCILLATION CONDITIONS
PublicationThe outcome of experimental research on a group of dry bearing materials carried out under small oscillation conditi ons and using a test rig designed and made at Gdansk University of Technology inspired the decision to find out if the stiffness of test head elements in fluenced the generated results. Therefore, a computer model utilising finite elements was devised and used to simulate the workings of the test head. The mode l...
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Wpływ cech konstrukcyjnych stanowiska badawczego na proces tarcia ślizgowego
PublicationZaprezentowano wyniki badań będących bezpośrednią kontynuacją wcześniejszych prac z zakresu badania drgań wywołanych tarciem. Badano konforemne płaskie skojarzenie pierścieniowe z monolitycznego Al2O,3 smarowanego olejem parafinowym. Badania wykonano na Tribometrze PT-3 wyposażonym w komputerowy system sterująco pomiarowy, umożliwiający wielokanałową szerokopasmową rejestrację przyspieszeń, sił i przemieszczeń. Układ badawczy tribometru...
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Visually validated semi-automatic high-frequency oscillation detection aides the delineation of epileptogenic regions during intra-operative electrocorticography
PublicationOBJECTIVE: To test the utility of a novel semi-automated method for detecting, validating, and quantifying high-frequency oscillations (HFOs): ripples (80-200 Hz) and fast ripples (200-600 Hz) in intra-operative electrocorticography (ECoG) recordings. METHODS: Sixteen adult patients with temporal lobe epilepsy (TLE) had intra-operative ECoG recordings at the time of resection. The computer-annotated ECoG recordings were visually...
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[PP.17.01] INCREASED INSPIRATORY RESISTANCE AFFECTS THE CARDIAC CONTRIBUTION TO THE RELATIONSHIP BETWEEN BLOOD PRESSURE AND PIAL ARTERY PULSATION OSCILLATIONS
PublicationThere is increasing evidence that heart performance directly influences cerebral perfusion. We hypothesised that increased inspiratory resistance would affect the cardiac contribution to the relationship between blood pressure and pial artery pulsation oscillations.
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Sympathetic Activation Does Not Affect the Cardiac and Respiratory Contribution to the Relationship between Blood Pressure and Pial Artery Pulsation Oscillations in Healthy Subjects
PublicationUsing a novel method called near-infrared transillumination backscattering sounding (NIR-T/BSS) that allows for the non-invasive measurement of pial artery pulsation (cc-TQ) and subarachnoid width (sas-TQ) in humans, we assessed the influence of sympathetic activation on the cardiac and respiratory contribution to blood pressure (BP) cc-TQ oscillations in healthy subjects. The pial artery and subarachnoid width response to handgrip...
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Increased inspiratory resistance alters the cardiac contribution to the dynamic relationship between blood pressure and pial artery pulsation oscillations in healthy subjects
PublicationThere is increasing evidence that heart performance directly influences cerebral perfusion. We hypothesised that increased inspiratory resistance will affect the cardiac contribution to the relationship between blood pressure and pial artery pulsation oscillations.
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THIRD-ORDER EXPONENTIAL INTEGRATOR FOR LINEAR KLEIN–GORDON EQUATIONS WITH TIME AND SPACE-DEPENDANT MASS
PublicationAllowing for space- and time-dependance of mass in Klein–Gordon equations re- solves the problem of negative probability density and of violation of Lorenz covariance of interaction in quantum mechanics. Moreover it extends their applicability to the domain of quantum cosmology, where the variation in mass may be accompanied by high oscillations....
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THIRD-ORDER EXPONENTIAL INTEGRATOR FOR LINEAR KLEIN–GORDON EQUATIONS WITH TIME AND SPACE-DEPENDANT MASS
PublicationAllowing for space- and time-dependance of mass in Klein–Gordon equations re- solves the problem of negative probability density and of violation of Lorenz covariance of interaction in quantum mechanics. Moreover it extends their applicability to the domain of quantum cosmology, where the variation in mass may be accompanied by high oscillations....
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Contribution to the mechanism of liquid membrane oscillators involving cationic surfactant.
PublicationIt is shown that liquid membrane oscillators with cationic surfactants havemore complex oscillation patterns than observed previously. The actual details of the oscillations depend strongly on the nature of the membrane material, dislosing even the presence of parallel molecular events. It appearsthat sampling topology also has a great influence on the observed oscillato-ry behaviour. Variation of oscillation patterns with...
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Modelowanie procesów oscylacyjnych w układach z membraną ciekłą i kationowym surfaktanetm = Modeling of oscillation processes in systems with liquid membrane and cationic surfactant
PublicationBadano mechanizm oscylacji róznicy potencjału elektrycznego między fazami wodnymi trójfazowego układu z membraną ciekłą zawierającą kwas pikrynowy rozpuszcony w nitrobenzenie. Wodna faza donorowa zawierała kationowy surfaktant (bromek heksadecylotrimetyloamoniowy) i etanol. Faza akceptorowa składała się z wodnego roztworu sacharozy. Mechanizm sugeruje, że gwałtowna adsorpcja i desorpcja surfaktantu na granicy fazy akceptorowej...
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Amplitude-distance spectroscopy in semi-contact mode
Open Research DataSince it was invented by Binnig et al. in 1986, atomic force microscopy (AFM) plays a key role in science and technology at the nanoscale. AFM is a microscopic technique that visualizes the surface topography using the attractive and repulsive forces of interaction between several atoms (in theory) of a blade attached to the end of the probe lever and...
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Neural oscillations induced by IAPS pictures (session 10)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 1)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 9)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 5)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 2)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 11)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 3)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 6)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 4)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 8)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 7)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 14)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 13)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 16)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 19)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 17)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 22)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 15)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...
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Neural oscillations induced by IAPS pictures (session 21)
Open Research DataThe data were collected to perform research on the possibility of controlling the content displayed on the monitor screen using human emotional states extracted from EEG signals. The dataset contains recordings of 14-channel EEG signals gathered from seven persons aged 23 - 35 within 26 sessions, during which 45 different random photos, taken from the...