Irina Böckelmann

Mobile Augmented Reality in industrial applications: Approaches for solution of user-related issues

Augmented Reality (AR) uses computer-generated virtual information to enhance the userpsilas information access. While numerous previous studies have demonstrated the large potential of AR to improve industrial processes by enhancing product quality and reducing production times it is still unclear if and how long term usage of such AR technology produces stress and strain. This paper presents an approach to use the analysis of Heart Rate Variability to objectively measure current user strain during different work tasks. Results of a user study comparing strain during an AR supported and a non-AR supported work task in a laboratory setting are presented and discussed.

Pick-by-Vision: A first stress test

In this paper we report on our ongoing studies around the application of Augmented Reality methods to support the order picking process of logistics applications. Order picking is the gathering of goods out of a prepared range of items following some customer orders. We named the visual support of this order picking process using Head-mounted Displays “Pick-by-Vision”. This work presents the case study of bringing our previously developed Pickby-Vision system from the lab to an experimental factory hall to evaluate it under more realistic conditions. This includes the execution of two user studies. In the first one we compared our Pickby-Vision system with and without tracking to picking using a paper list to check picking performance and quality in general. In a second test we had subjects using the Pick-by-Vision system continuously for two hours to gain in-depth insight into the longer use of our system, checking user strain besides the general performance. Furthermore, we report on the general obstacles of trying to use HMD-based AR in an industrial setup and discuss our observations of user behaviour.

Einfluss langjähriger beruflicher Lösemittelexposition auf das Farbensehen

ZusammenfassungHintergrund. Ziel der Arbeit ist es, bei Autolackierern den Einfluss einer chronischen beruflichen Lösemittelgemischexposition auf das Farbensehen zu untersuchen. Probanden und Methoden. Die 123 Arbeitnehmer (zwei Gruppen von lösemittelexponierten Lackierern und eine Kontrollgruppe) wurden mittels Ishihara-Tafeln, Lanthony-Desaturated-Panel-D-15-Test,Velhagen-Tafeln und Tritan-Album untersucht. Ergebnisse. Mittels Velhagen-Tafeln wurde bei 3% der aktuell lösemittelexponierten Lackierer und bei 11% der ehemalig Lösemittelexponierten eine Blau-Gelb-Störung für das rechte Auge festgestellt.Alle Kontrollpersonen konnten fehlerfrei die Tafeln lesen; 3% der aktuell und 26% der ehemalig Lösemittelexponierten hatten im Tritan-Test für das rechte Auge eine Blau-Gelb-Störung, aber auch in der Kontrollgruppe zeigten 7% der Probanden die Anomalität. Ähnliche Ergebnisse in beiden Tests wurden für das linke Auge festgestellt.Die CCI-Unterschiede in dem D-15-Test zwischen den drei Gruppen waren statistisch signifikant. Schlussfolgerung. Die Beeinträchtigung des Farbensehens ist ein wichtiger Indikator der neuroophthalmologischen Veränderungen, die durch chronische Lösemittelexposition hervorgerufen werden können.AbstractBackground. The study was designed to determine the influence of chronic occupational exposition of organic solvent mixtures on colour vision of car painters. Subjects and methods. The 123 subjects (2 groups differing in organic solvents exposure and 1 control group) were examined using Ishihara-Panel,Lanthony Desaturated Panel D-15,Velhagen-Panel, and Tritan-Album. Results. In the Velhagen-Panel 3% of the probands currently exposed to organic solvents, and 11% of formerly exposed probands developed a blue/yellow vision defect for the right eye. All control subjects perfectly finished this panel. In the Tritan-Album 3% of currently exposed subjects and 26% of formerly exposed painters expressed a blue/yellow vision defect for the right eye, but also 7% of controls showed anomalies. Similar results were found for both panels with the left eye.The CCI difference in the D-15 Ttest was significant between all three groups. Conclusion. The impaired colour vision may also be an important indicator of neuro-ophthalmological effects after long-term occupational exposure to organic solvents.

Assessing the suitability of cross-sectional and longitudinal cardiac rhythm tests with regard to identifying effects of occupational chronic lead exposure.

The aim of this study was to examine whether signs of neurotoxic influence on the autonomic nervous system, after lengthy occupational lead exposure, could be revealed by appropriate cardiac rhythm analysis. A total of 109 male lead-exposed workers and 27 controls were examined in a cross-sectional study. In addition, 17 lead-exposed participants were investigated a second time in a follow-up study 4 years later. Heart rate variability was assessed in rest, strain, and recovery phases. In the cross-sectional study, lead-exposed persons showed a delayed restoration of cardiac rhythm parameters to the initial vegetative state after the strain phase. This effect significantly increased over a period of 4 more years of exposure in the 17 workers participating in the follow-up study. We found vagal depression caused by long-term lead exposure within the current threshold limit value range, which can be interpreted as an adverse effect.

Perceptual issues in optical-see-through displays

Optical see-through devices enable observers to see additional information embedded in real environments. There is already some evidence of increasing visual load in respective systems. We investigated visual performance when users performed visual search tasks or dual tasks only on the optical see-through device, only on a computer screen, or switching between both. In spite of having controlled for basic differences between both devices, switching between the presentation devices produced costs in visual performance. The assumption that these decreases in performance are partly due to differences localizing the presented objects was confirmed by convergence data.

Reference values for time- and frequency-domain heart rate variability measures

BACKGROUND The analysis of heart rate variability (HRV) has become an established procedure in recent decades. Because there are no appropriate reference values available, HRV findings can still only be compared within a group or in individuals in longitudinal studies. OBJECTIVE The objectives of the present study were to examine a group of healthy subjects of different ages and sexes and to identify reference values for common HRV parameters. METHODS Long-term 24-hour electrocardiograms of 695 voluntary subjects were recorded by using a 2-channel Holter system over a period of 24 hours during daily activities. RESULTS Reference values for men and women in 10-year age groups were calculated for standard deviation of NN intervals, root mean square of successive differences of NN intervals, standard deviation of the average of all consecutive 5-minute NN intervals, percentage of consecutive NN intervals that deviate from one another by more than 50 ms, low-frequency power normalized unit, high-frequency power normalized unit, low frequency/high frequency ratio, SD1, and SD2. The 5th and 95th percentiles were given for each sex and for the age groups 20-30, 30-40, 40-50, and 50-60 years. We observed a consistent decrease in HRV measures with increasing age as well as a sex dependency of HRV findings. CONCLUSION We studied a large group of healthy subjects and identified reference values for commonly used HRV measures for 24-hour ECG measurements. The reference values differed considerably from the values published in 1996 in the Guidelines of the Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. In the future, steps should be taken to expand the database and define reference values for the age groups under 20 and over 60 years. It would be desirable to obtain reference values for short-term recordings (eg, 5-minute recordings) as well.

Vegetative function diagnosis for early detection of lead intoxication

In the search for the early effects of neurotoxic lead poisoning, vegetative function diagnosis is a potential approach, focusing on the behaviour of the cardiac rhythm. Four groups of male subjects (109 copper workers exhibiting mean lead levels in blood of 31.2 μg/dl after long-term lead exposure; 27 control subjects having a similar job in the iron and steel industry without neurotoxic exposure; 35 reference subjects from Magdeburg University Hospital without neurotoxic exposure, and 5 subjects to whom benefits have been awarded for disability resulting from lead intoxication) were studied. All subjects underwent the same psychometric test battery. Special attention was paid to the restoration of vegetative tone after exposure. The more extensive the exposure to lead, the longer was the delay in restoration. This effect seems to be reversible, as workers heavily exposed to lead, but otherwise healthy, were more affected than the patients included in this investigation. Simply comparing the cardiac rhythm of exposed and non-exposed subjects at rest is not sufficient for early detection of lead intoxication. The behaviour of cardiac rhythm in humans at rest is the result of long-term influence by a wide range of factors, of which lead exposure is only one.

Extended investigations of user-related issues in mobile industrial AR

The potential of Augmented Reality (AR) to support industrial processes has been demonstrated in several studies. While there have been first investigations on user related issues in the long-duration use of mobile AR systems, to date the impact of theses systems on physiological and psychological aspects is not explored extensively. We conducted an extended study in which 19 participants worked 4 hours continuously in an order picking process with and without AR support. Results of the study comparing strain and work efficiency are presented and open issues are discussed.

Psychological effects of occupational exposure to organic solvent mixtures on printers

Purpose: Neuropsychiatric symptoms associated with long-term exposure to organic solvents have been investigated for a long time in many occupational studies. The aim of our study was to identify preclinical effects of low-level chronic solvent exposure on the cognitive performance of silk-screen printers. Methods: A cross-sectional study was conducted including 38 printers which were exposed to organic solvent mixtures and 45 controls without neurotoxic exposure. The psychometric test battery included nine tests and two questionnaires. Results: The sum of scales or the total score of the PNF was also significantly (p < 0.001) higher in the exposed group than in the non-exposed. The printers performed worse in some psychometric tests than did controls. Cross validation with the psychometric performances resulted in 69.6% of participants being correctly classified (55.9% printers and 80% controls). Highly significant differences (p < 0.001) between both groups of exposed and non-exposed workers were found for the mean values of the multidimensional psychometric score. Conclusions: These results of our study proved not only that chronic exposure to organic solvent mixtures could induce a psychological effect but also that the psychological/psychometrical tests performed in this study were capable of predicting neurotoxicity.

Analyse der Herzfrequenzvariabilität (HRV) — praktische Relevanz

ZusammenfassungDie Herzfrequenzvariabilität wird durch Analyse der Variation des Intervalls zwischen konsekutiven Normal-Herzschlägen berechnet. Das Intervall zwischen zwei R-Zacken im EKG wird als Abstand zwischen jeweils zwei aufeinanderfolgenden Herzschlägen im physiologischen Rhythmus bezeichnet. Die Änderungen der Herzfrequenz werden vom autonomen Nervensystem (sympathischen und parasympathischen) gesteuert. Diese Variabilität der Herzschlagfolge ist ein physiologisches Phänomen entsprechend der verschiedenen physiologischen Erfordernisse. Die hohe Herzfrequenzvariabilität ist Zeichen einer guten Adaptation, was einem gesunden Individuum mit gut funktionierenden Kontrollmechanismen im autonomen Nervensystem entspricht. Demgegenüber ist die niedrige Variabilität der Herzschlagfolge ein Indikator für nicht ausreichende Adaptationsmechanismen und Beeinträchtigungen in den autonomen Regulationsmechanismen des Herzschlages. Die Methoden der HRV-Analyse differenziert man in zeit- und frequenzbezogene Methoden sowie nichtlineare Methoden.In Abhängigkeit von der Fragestellung (Beanspruchungsreaktion, Antwort in einer Stresssituation, klinische Studie, Diagnostik u. a.) kann sich die Erfassung der HRV von einem kürzeren (bis 5 Minuten) bis zu einem sehr langen Zeitraum (24-h-EKG) erstrecken. Die HRV-Analyse gewinnt momentan in der wissenschaftlichen Forschung und Klinik generell und auch in der Arbeitsmedizin an Bedeutung. Die Anwendungsfelder sind vielfältig (z.B. Messen von Beanspruchung bei psychischer Belastung, Risikostratifizierung).AbstractHeart rate variability (HRV) is quantified by the analysis of variations of the intervals between consecutive normal heart beats. The interval between two R wave peaks of an ECG is referred as the distance between two successive heart beats in normal rhythm. The changes in heart rate are controlled by the autonomic nervous system (sympathetic and parasympathetic). This variation in the beat-to-beat interval is a physiological phenomenon and a reliable reflection of the many physiological factors modulating the normal rhythm of the heart. High heart rate variability is a sign of good adaptability, indicating a healthy individual with good functioning autonomic control mechanisms. On the contrary, low heart rate variability is often an indicator of insufficient adaptability and impairment in autonomic control of the heart in the individual. The standard non-invasive measurements intervening in the analysis of HRV comprise time domain, frequency domain, and non-linear techniques. The measurements of HRV are generally implemented on the basis of 24h-Holter-ECG recording (long-term recordings) or on shorter 5 minute periods (short-term recordings). The way of recording depends on the aim of the study that has to be realized (strain reaction, stress situation, clinical practice, diagnostic etc.). The RR variability gains relevance in many medical fields including occupational medicine. Measures of HRV may indicate psychosocial load at the workplace and also seems to have predictive value for the occurrence of cardiovascular diseases.