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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Измерение когнитивной нагрузки с помощью оценки показателей фотоплетизмограммы : магистерская диссертация / Measuring cognitive load by evaluating photoplethysmogram indicators

Гашкова, А. С., Gashkova, A. S. January 2024 (has links)
Когнитивная нагрузка является решающим фактором в умственно напряженной деятельности, т.к. на прямую связана с продуктивностью деятельности, обучаемостью и имеет решающее значение в педагогике, профессиональной среде. Также актуальным остается вопрос о нахождении наиболее простого и точного метода для обнаружения когнитивной перегрузки. Цель исследования: изучить эффективность показателей фотоплетизмограммы для отслеживания когнитивной нагрузки, обнаружения состояния когнитивной перегрузки. В работе рассмотрены общие теоретические положения, связанные с теорией когнитивной нагрузки, рабочей памяти. Проведен обзор маркеров когнитивной нагрузки на показателях сердечной деятельности. Анализ результатов фотоплетизмографии 119 человек показал, что амплитуда пульсовой волны (АПВ), частота сердечных сокращений (ЧСС) оказалась чувствительна к когнитивной перегрузке (p <0.001). А также состояние перегрузки значительно влияет на АПВ. Полученные результаты способствуют пониманию психофизиологических показателей когнитивной нагрузки и дают представление об использовании АПВ в качестве неинвазивного метода. / Cognitive load is a decisive factor in mentally stressful activities, because it is directly related to productivity, learning ability and is crucial in pedagogy and the professional environment. The question of finding the simplest and most accurate method for detecting cognitive overload also remains relevant. The purpose of the study: to study the effectiveness of photoplethysmogram indicators for tracking cognitive load, detecting the state of cognitive overload. The paper considers general theoretical positions related to the theory of cognitive load and working memory. The review of markers of cognitive load on cardiac activity indicators was carried out. Analysis of the results of photoplethysmography of 119 people showed that the pulse wave amplitude (PWA) and heart rate (HR) were sensitive to cognitive overload (p <0.001). Also, the overload condition significantly affects the PWA. The results obtained contribute to the understanding of psychophysiological indicators of cognitive load and give an idea of the use of PWA as a non-invasive method.
12

Assessment of blind source separation techniques for video-based cardiac pulse extraction

Wedekind, Daniel, Trumpp, Alexander, Gaetjen, Frederik, Rasche, Stefan, Matschke, Klaus, Malberg, Hagen, Zaunseder, Sebastian 09 September 2019 (has links)
Blind source separation (BSS) aims at separating useful signal content from distortions. In the contactless acquisition of vital signs by means of the camera-based photoplethysmogram (cbPPG), BSS has evolved the most widely used approach to extract the cardiac pulse. Despite its frequent application, there is no consensus about the optimal usage of BSS and its general benefit. This contribution investigates the performance of BSS to enhance the cardiac pulse from cbPPGs in dependency to varying input data characteristics. The BSS input conditions are controlled by an automated spatial preselection routine of regions of interest. Input data of different characteristics (wavelength, dominant frequency, and signal quality) from 18 postoperative cardiovascular patients are processed with standard BSS techniques, namely principal component analysis (PCA) and independent component analysis (ICA). The effect of BSS is assessed by the spectral signal-tonoise ratio (SNR) of the cardiac pulse. The preselection of cbPPGs, appears beneficial providing higher SNR compared to standard cbPPGs. Both, PCA and ICA yielded better outcomes by using monochrome inputs (green wavelength) instead of inputs of different wavelengths. PCA outperforms ICA for more homogeneous input signals. Moreover, for high input SNR, the application of ICA using standard contrast is likely to decrease the SNR.
13

Improving Deep Representations by Incorporating Domain Knowledge and Modularization for Synthetic Aperture Radar and Physiological Data

Agarwal, Tushar January 2022 (has links)
No description available.

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