Ralf Seepold

Prof. Dr. Ralf Seepold

Ubiquitous Computing Lab, Hochschule Konstanz University of Applied Sciences, Konstanz, Baden-Württemberg, Germany
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Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

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

Representative Publications

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15 September 2020 in Sensors
Verified
Journal Article
Open access
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VMVictor Corcoba Magaña
Victor Corcoba Magaña
WSWilhelm Daniel Scherz
Wilhelm Daniel Scherz
Ralf SeepoldRalf Seepold
Ralf Seepold
Natividad Martínez MadridNatividad Martínez Madrid
Natividad Martínez Madrid
XPXabiel García Pañeda
Xabiel García Pañeda
RGRoberto Garcia
Roberto Garcia
Globalization has increased the number of road trips and vehicles. The result has been an intensification of traffic accidents, which are becoming one of the most important causes of death worldwide. Traffic accidents are often due to human error, the probability of which increases when the cognitive ability of the driver decreases. Cognitive capacity is closely related to the driver’s mental state, as well as other external factors such as the CO2 concentration inside the vehicle. The objective of this work is to analyze how these elements affect driving. We have conducted an experiment with 50 drivers who have driven for 25 min using a driving simulator. These drivers completed a survey at the start and end of the experiment to obtain information about their mental state. In addition, during the test, their stress level was monitored using biometric sensors and the state of the environment (temperature, humidity and CO2 level) was recorded. The results of the experiment show that the initial level of stress and tiredness of the driver can have a strong impact on stress, driving behavior and fatigue produced by the driving test. Other elements such as sadness and the conditions of the interior of the vehicle also cause impaired driving and affect compliance with traffic regulations.

1 January 2019 in Procedia Computer Science
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Journal Article
Open access
MGMarkus Gromer
Markus Gromer
DSDavid Salb
David Salb
TWThomas Walzer
Thomas Walzer
Natividad Martínez MadridNatividad Martínez Madrid
Natividad Martínez Madrid
Ralf SeepoldRalf Seepold
Ralf Seepold

10 July 2023 in Biomedical Engineering Letters
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Journal Article
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Maksym GaidukMaksym Gaiduk
Maksym Gaiduk
ÁAÁngel Serrano Alarcón
Ángel Serrano Alarcón
Ralf SeepoldRalf Seepold
Ralf Seepold
Natividad Martínez MadridNatividad Martínez Madrid
Natividad Martínez Madrid
The scoring of sleep stages is one of the essential tasks in sleep analysis. Since a manual procedure requires considerable human and financial resources, and incorporates some subjectivity, an automated approach could result in several advantages. There have been many developments in this area, and in order to provide a comprehensive overview, it is essential to review relevant recent works and summarise the characteristics of the approaches, which is the main aim of this article. To achieve it, we examined articles published between 2018 and 2022 that dealt with the automated scoring of sleep stages. In the final selection for in-depth analysis, 125 articles were included after reviewing a total of 515 publications. The results revealed that automatic scoring demonstrates good quality (with Cohen's kappa up to over 0.80 and accuracy up to over 90%) in analysing EEG/EEG + EOG + EMG signals. At the same time, it should be noted that there has been no breakthrough in the quality of results using these signals in recent years. Systems involving other signals that could potentially be acquired more conveniently for the user (e.g. respiratory, cardiac or movement signals) remain more challenging in the implementation with a high level of reliability but have considerable innovation capability. In general, automatic sleep stage scoring has excellent potential to assist medical professionals while providing an objective assessment.

24 May 2023 in Sensors
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Andrei BoikoAndrei Boiko
Andrei Boiko
Natividad Martínez MadridNatividad Martínez Madrid
Natividad Martínez Madrid
Ralf SeepoldRalf Seepold
Ralf Seepold
Sleep is essential to physical and mental health. However, the traditional approach to sleep analysis—polysomnography (PSG)—is intrusive and expensive. Therefore, there is great interest in the development of non-contact, non-invasive, and non-intrusive sleep monitoring systems and technologies that can reliably and accurately measure cardiorespiratory parameters with minimal impact on the patient. This has led to the development of other relevant approaches, which are characterised, for example, by the fact that they allow greater freedom of movement and do not require direct contact with the body, i.e., they are non-contact. This systematic review discusses the relevant methods and technologies for non-contact monitoring of cardiorespiratory activity during sleep. Taking into account the current state of the art in non-intrusive technologies, we can identify the methods of non-intrusive monitoring of cardiac and respiratory activity, the technologies and types of sensors used, and the possible physiological parameters available for analysis. To do this, we conducted a literature review and summarised current research on the use of non-contact technologies for non-intrusive monitoring of cardiac and respiratory activity. The inclusion and exclusion criteria for the selection of publications were established prior to the start of the search. Publications were assessed using one main question and several specific questions. We obtained 3774 unique articles from four literature databases (Web of Science, IEEE Xplore, PubMed, and Scopus) and checked them for relevance, resulting in 54 articles that were analysed in a structured way using terminology. The result was 15 different types of sensors and devices (e.g., radar, temperature sensors, motion sensors, cameras) that can be installed in hospital wards and departments or in the environment. The ability to detect heart rate, respiratory rate, and sleep disorders such as apnoea was among the characteristics examined to investigate the overall effectiveness of the systems and technologies considered for cardiorespiratory monitoring. In addition, the advantages and disadvantages of the considered systems and technologies were identified by answering the identified research questions. The results obtained allow us to determine the current trends and the vector of development of medical technologies in sleep medicine for future researchers and research.

1 December 2018 in Physiological Measurement
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Maksym GaidukMaksym Gaiduk
Maksym Gaiduk
Thomas PenzelThomas Penzel
Thomas Penzel
Juan A. OrtegaJuan A. Ortega
Juan A. Ortega
Ralf SeepoldRalf Seepold
Ralf Seepold
Objective : This paper presents an algorithm for non-invasive sleep stage identification using respiratory, heart rate and movement signals. The algorithm is part of a system suitable for long-term monitoring in a home environment, which should support experts analysing sleep. Approach : As there is a strong correlation between bio-vital signals and sleep stages, multinomial logistic regression was chosen for categorical distribution of sleep stages. Several derived parameters of three signals (respiratory, heart rate and movement) are input for the proposed method. Sleep recordings of five subjects were used for the training of a machine learning model and 30 overnight recordings collected from 30 individuals with about 27 000 epochs of 30 s intervals each were evaluated. Main results : The achieved rate of accuracy is 72% for Wake, NREM, REM (with Cohen’s kappa value 0.67) and 58% for Wake, Light (N1 and N2), Deep (N3) and REM stages (Cohen’s kappa is 0.50). Our approach has confirmed the potential of this method and disclosed several ways for its improvement. Significance : The results indicate that respiratory, heart rate and movement signals can be used for sleep studies with a reasonable level of accuracy. These inputs can be obtained in a non-invasive way applying it in a home environment. The proposed system introduces a convenient approach for a long-term monitoring system which could support sleep laboratories. The algorithm which was developed allows for an easy adjustment of input parameters that depend on available signals and for this reason could also be used with various hardware systems.

14 March 2016 in Journal of Tourism Futures
Verified
Journal Article
Open access
TTTatjana Thimm
Tatjana Thimm
Ralf SeepoldRalf Seepold
Ralf Seepold
Purpose: The purpose of this paper is to find out tourism movement patterns via the tracking of tourists with the help of positioning systems like GPS in the rural area of the Lake Constance destination in Germany. In doing so past, present and future of tourist tracking is illustrated. Design/methodology/approach: The tracking is realized via common smartphones extended by an app, with dedicated sensors like position loggers and a survey. The three different approaches are applied in order to compare and cross-check results (triangulation of data and methods). Findings: Movement patterns turned out to be diverse and individualistic within the rural destination of Lake Constance and following an ants trail in sub-destinations like the city of Constance. Repeat visitors and first-time visitors alike always visit the bigger cities and main day-trip destinations of the Lake. A possible prediction tool enables new avenues of governing tourism movement patterns. Research limitations/implications: The tracking techniques can be developed further into the direction of “quantified self” using gamification in order to make the tracking app even more attractive. Practical implications: An algorithm-based prediction tool would offer new perspectives to the management of tourism movements. Social implications: Further research is needed to overcome the feeling of invasiveness of the app to allow tracking with that approach. Originality/value: This study is original and innovative because of the first-time use of a smartphone app in tourist tracking, the application on a rural destination and the conceptual description of a prediction tool.