Marcin Kołodziej

Prof. Marcin Kołodziej

Warsaw University of Technology, Warsaw, Mazowieckie, Poland
orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 January 2017 in Procedia Computer Science
Verified
Journal Article
Open access
PTPaweł Tarnowski
Paweł Tarnowski
MKMarcin Kołodziej
Marcin Kołodziej
AMAndrzej Majkowski
Andrzej Majkowski
RRRemigiusz J. Rak
Remigiusz J. Rak

1 September 2020 in Computational Intelligence and Neuroscience
Verified
Journal Article
Open access
PDF file
PTPaweł Tarnowski
Paweł Tarnowski
MKMarcin Kołodziej
Marcin Kołodziej
AMAndrzej Majkowski
Andrzej Majkowski
RRRemigiusz Jan Rak
Remigiusz Jan Rak
This article reports the results of the study related to emotion recognition by using eye-tracking. Emotions were evoked by presenting a dynamic movie material in the form of 21 video fragments. Eye-tracking signals recorded from 30 participants were used to calculate 18 features associated with eye movements (fixations and saccades) and pupil diameter. To ensure that the features were related to emotions, we investigated the influence of luminance and the dynamics of the presented movies. Three classes of emotions were considered: high arousal and low valence, low arousal and moderate valence, and high arousal and high valence. A maximum of 80% classification accuracy was obtained using the support vector machine (SVM) classifier and leave-one-subject-out validation method.

29 July 2020 in IEEE Sensors Journal
Verified
Journal Article
Closed access
MKMarcin Kołodziej
Marcin Kołodziej
PTPaweł Tarnowski
Paweł Tarnowski
DSDariusz Sawicki
Dariusz Sawicki
AMAndrzej Majkowski
Andrzej Majkowski
RRRamigiusz J. Rak
Ramigiusz J. Rak
APAgnieszka Pluta
Agnieszka Pluta
Although the psychophysiological signs of fatigue are well known, automatic methods for the detection of fatigue in employees in specific working conditions are still lacking. Many people do repetitive work on computers and become fatigued; therefore, the detection of fatigue in employees can help prevent accidents and increase their work efficiency. In this paper, we propose an algorithm for the effective detection of fatigue which is based only on electrooculographic (EOG) signal. Three features were assessed: blink duration, blink amplitude, and time between blinks. To cause fatigue, the N-back test, lasting for 60 minutes, was carried out. The article presents the research results for 24 users. The effectiveness of the proposed system was measured by the accuracy of classification. The average classification accuracy was 0.93 for user-dependent mode and 0.89 for user-independent mode. The results of the conducted experiments indicated that assessing the three proposed features can help in the effective detection of fatigue in users.

26 October 2017 in Applied Psychophysiology and Biofeedback
Verified
Journal Article
Open access
PDF file
DZDariusz Zapała
Dariusz Zapała
PFPiotr Francuz
Piotr Francuz
EZEwelina Zapała
Ewelina Zapała
NKNatalia Kopiś
Natalia Kopiś
PWPiotr Wierzgała
Piotr Wierzgała
MKMarcin Kołodziej
Marcin Kołodziej
The challenges of research into brain–computer interfaces (BCI) include significant individual differences in learning pace and in the effective operation of BCI devices. The use of neurofeedback training is a popular method of improving the effectiveness BCI operation. The purpose of the present study was to determine to what extent it is possible to improve the effectiveness of operation of sensorimotor rhythm-based brain–computer interfaces (SMR-BCI) by supplementing user training with elements modifying the characteristics of visual feedback. Four experimental groups had training designed to reinforce BCI control by: visual feedback in the form of dummy faces expressing emotions (Group 1); flashing the principal elements of visual feedback (Group 2) and giving both visual feedbacks in one condition (Group 3). The fourth group participated in training with no modifications (Group 4). Training consisted of a series of trials where the subjects directed a ball into a basket located to the right or left side of the screen. In Group 1 a schematic image a face, placed on the controlled object, showed various emotions, depending on the accuracy of control. In Group 2, the cue and targets were flashed with different frequency (4 Hz) than the remaining elements visible on the monitor. Both modifications were also used simultaneously in Group 3. SMR activity during the task was recorded before and after the training. In Group 3 there was a significant improvement in SMR control, compared to subjects in Group 2 and 4 (control). Differences between subjects in Groups 1, 2 and 4 (control) were insignificant. This means that relatively small changes in the training procedure may significantly impact the effectiveness of BCI control. Analysis of behavioural data acquired from all participants at training showed greater effectiveness in directing the object towards the right side of the screen. Subjects with the greatest improvement in SMR control showed a significantly lower difference in the accuracy of rightward and leftward movement than others.

1 January 2012 in Metrology and Measurement Systems
Verified
Journal Article
Closed access
PDF file
RRRemigiusz J. Rak
Remigiusz J. Rak
MKMarcin Kołodziej
Marcin Kołodziej
AMAndrzej Majkowski
Andrzej Majkowski
In the last decade of the XX-th century, several academic centers have launched intensive research programs on the brain-computer interface (BCI). The current state of research allows to use certain properties of electromagnetic waves (brain activity) produced by brain neurons, measured using electroencephalographic techniques (EEG recording involves reading from electrodes attached to the scalp - the non-invasive method - or with electrodes implanted directly into the cerebral cortex - the invasive method). A BCI system reads the user's “intentions” by decoding certain features of the EEG signal. Those features are then classified and "translated" (on-line) into commands used to control a computer, prosthesis, wheelchair or other device. In this article, the authors try to show that the BCI is a typical example of a measurement and control unit.

1 May 2018
Verified
Conference Paper
Closed access
PTPawel Tarnowski
Pawel Tarnowski
MKMarcin Kołodziej
Marcin Kołodziej
AMAndrzej Majkowski
Andrzej Majkowski
RRRemigiusz Jan Rak
Remigiusz Jan Rak
An article presents the results of research related to the detection of emotions using combined analysis of galvanic skin response (GSR) and electroencephalographic (EEG) signals. Twenty seven volunteers participated in the experiment. Emotions were evoked by presentation of a set of twenty one movies. Emotions, evoked by individual movies, were later rated by participants according to valence and arousal. GSR signal was used to indicate the most stimulating movies, then features extracted from EEG signal were used to classify emotions. To determine the features EEG signal was analyzed in the frequency domain using fast Fourier transform (FFT) algorithm. For classifying emotions, according to valence and arousal, two classifiers were implemented: support vector machine (SVM) and k-nearest neighbors (k-NN).