Evaluation of different feedback designs for target guidance in human controlled robotic cranes: A comparison between high and low performance groups.

Labour shortages and costly operator training are driving the need for digital on-board robotic crane operator support in forestry and construction. This simulator study investigated the effects of sonification (auditory, pitch/loudness) and continuous visual (brightness/size) feedback on aiming movements with a robotic crane for low and high performers. The feedback was designed non-linear and linear. Thirty-six participants controlled a robotic crane bimanually using joysticks across 320 movements. Performance and skill indicators (movement time, accuracy, trajectory, smoothness) as well as satisfaction, and usefulness were assessed. Low-performing participants showed higher movement accuracy, particularly with non-linear pitch feedback compared to visual feedback. High performers exhibited no significant performance improvement in movement time, accuracy, or smoothness. There was no effect of linear or non-linear mapping of the feedback. Additionally, perceived satisfaction was lower with auditory than visual feedback. These results suggest that real-time auditory feedback can enhance operator accuracy whereas acceptance remains challenging.

Analysis of learning the bimanual control of (tele)operating joint space controlled robotic arms with 4 degrees of freedom using the two-timescales power law of learning.

Training costs for operators of robotic arms in forestry and construction are high. A systematic analysis of skill development can help to make training more efficient. This research focuses on motor skill development by investigating the bimanual control of a four-DoF robotic arm. The two-time scale power law of learning was used to identify difficulties in control learning. Ten participants acquired the control of the robotic arm in a simulator over ten sessions within seven weeks. Eight movement targets were presented in each of six blocks per session, comprising 432 robotic arm movements. The results suggest that learning varies for each joystick axis, with control of the elbow joint showing the highest learning gain. The base and shoulder joints showed similar learning gains. The wrist joint showed mixed results in terms of use or disuse. Performance increased with retention, suggesting that a longer period of consolidation aided skill acquisition.Practitioner summary: A shortage of skilled operators, costly, and extensive training of heavy machine operators in robotic arm control requires to revisit control skill learning. This study showed that focus of training ought to be shifted to specific joints and training requires to emphasise longer resting periods between training sessions.

Neuroergonomics on the Go: An Evaluation of the Potential of Mobile EEG for Workplace Assessment and Design.

OBJECTIVE: We demonstrate and discuss the use of mobile electroencephalogram (EEG) for neuroergonomics. Both technical state of the art as well as measures and cognitive concepts are systematically addressed. BACKGROUND: Modern work is increasingly characterized by information processing. Therefore, the examination of mental states, mental load, or cognitive processing during work is becoming increasingly important for ergonomics. RESULTS: Mobile EEG allows to measure mental states and processes under real live conditions. It can be used for various research questions in cognitive neuroergonomics. Besides measures in the frequency domain that have a long tradition in the investigation of mental fatigue, task load, and task engagement, new approaches-like blink-evoked potentials-render event-related analyses of the EEG possible also during unrestricted behavior. CONCLUSION: Mobile EEG has become a valuable tool for evaluating mental states and mental processes on a highly objective level during work. The main advantage of this technique is that working environments don't have to be changed while systematically measuring brain functions at work. Moreover, the workflow is unaffected by such neuroergonomic approaches.

Did you even see that? visual sensory processing of single stimuli under different locomotor loads.

Modern living and working environments are more and more interspersed with the concurrent execution of locomotion and sensory processing, most often in the visual domain. Many job profiles involve the presentation of visual information while walking, for example in warehouse logistics work, where a worker has to manage walking to the correct aisle to pick up a package while being presented with visual information over data-glasses concerning the next order. Similar use-cases can be found in manufacturing jobs, for example in car montage assembly lines where next steps are presented via augmented reality headsets while walking at a slow pace. Considering the overall scarcity of cognitive resources available to be deployed to either the cognitive or motor processes, task performance decrements were found when increasing load in either domain. Interestingly, the walking motion also had beneficial effects on peripheral contrast detection and the inhibition of visual stream information. Taking these findings into account, we conducted a study that comprised the detection of single visual targets (Landolt Cs) within a broad range of the visual field (-40° to +40° visual angle) while either standing, walking, or walking with concurrent perturbations. We used questionnaire (NASA-TLX), behavioral (response times and accuracy), and neurophysiological data (ERPs and ERSPs) to quantify the effects of cognitive-motor interference. The study was conducted in a Gait Real-time Analysis Interactive Laboratory (GRAIL), using a 180° projection screen and a swayable and tiltable dual-belt treadmill. Questionnaire and behavioral measures showed common patterns. We found increasing subjective physical workload and behavioral decrements with increasing stimulus eccentricity and motor complexity. Electrophysiological results also indicated decrements in stimulus processing with higher stimulus eccentricity and movement complexity (P3, Theta), but highlighted a beneficial role when walking without perturbations and processing more peripheral stimuli regarding earlier sensory components (N1pc/N2pc, N2). These findings suggest that walking without impediments can enhance the visual processing of peripheral information and therefore help with perceiving non-foveal sensory content. Also, our results could help with re-evaluating previous findings in the context of cognitive-motor interference, as increased motor complexity might not always impede cognitive processing and performance.

[Intralogistics in the age of digital change: Job demands and mental strain in order picking using the example of a company from the e-commerce sector]. / Intralogistik im Zeitalter des digitalen Wandels: Arbeitsanforderungen und psychische Beanspruchung in der Kommissionierung am Beispiel eines Unternehmens aus dem E-Commerce-Bereich.

The e­commerce sector is experiencing a continuous boom in logistics due to digitization. Along with mostly manual activities, people remain a decisive resource in the warehouse, which must be retained and integrated with a particular view to demographic change. In the article, the survey results of a field study with focus on the area of order picking, which was conducted at a large mail-order company, are described as an example and compared with survey results from other companies. Based on the job demand resources model, stressors, challenges and resources are examined in addition to the target variables of work ability, job satisfaction and health. The results indicate that stressors and work resources roughly keep the balance, even if, for example, job satisfaction and health are only at a medium level. Above all, there is still a need of action regarding autonomy of employees. The digital transformation is seen as an opportunity to expand the scope for action and decision-making.Practical Relevance: Due to the manual nature of the activities and the predefined processes, operational logistics involves a large number of work demands that can lead to mental strain and, in the long term, to disorders or illnesses. The expansion of work-related resources is necessary to compensate for the stressors. Digitization is seen as an opportunity to expand these resources.

Individual-Level Interventions for Decreasing Job-Related Stress and Enhancing Coping Strategies Among Nurses: A Systematic Review.

Background: Nurses are facing unprecedented amounts of pressure because of the ongoing global health challenges. Improving nurses' resilience to job-related stress and enhancing their strategies to cope effectively with stressors are key issues facing many health care institutions during the COVID-19 pandemic. This literature review aimed to: a) provide a thorough overview of individual-level interventions for stress management among nurses, b) identify measurement tools utilized to evaluate nurses' stress level, and c) provide the best evidence-based recommendations for future research and practice adapted to the current restrictions. Design: Systematic review. Data Sources: Studies published between January 2000 and October 2020 were retrieved from the following sources: EBSCOhost, Dortmund University Library, PubMed, Medline, Google Scholar, Applied Nursing Research, and reference lists from relevant articles. Review methods: Individual-level interventions with a control group or a placebo intervention were included in the final sample. Primary outcome was defined as a change in individual stress level or stress symptoms which were measured by objective or subjective instruments with evidence of validity. Articles published in English or German were included in the present review. Results: In total, 27 relevant studies were included into the current review. There are some indications that technology-delivered interventions with relaxation and stress management interventions comprising cognitive-behavioral components might be effective in decreasing stress among nurses and improving their well-being. Furthermore, although there were some attempts to collect objectively measured parameters for assessing the primary outcome of stress, the majority of the interventions utilized self-reported stress scales. Conclusion: A wide range of interventions are available for nurses. However, it is of utmost importance to develop and implement stress management programs that are conveniently accessible in the workplace and above all, meet the current restrictions for minimizing human contacts. To this end, innovative interventions delivered through digital technology, such as virtual reality, seem to be a promising solution for combating the detrimental impact of stress on nurses. Special attention should be also paid to applying standardized objective measurement tools to allow the assessment of sensitive physiological indices and the generalizability of scientific knowledge.

Capturing Interactive Work for Nurses-First Validation of the German IWDS-N as a Multidimensional Measure.

The theoretical framework of interactive work provides a multi-dimensional perspective on the interpersonal demands of nurses in nurse-patient interactions. It is defined by four dimensions: emotional labor directed to the self and others, cooperative work, and subjective acting. While the framework stems from qualitative research, the aim of the current study is to translate it into a quantitative scale to enable measurement of the high interpersonal demands that so often remain implicit. For this reason, we conducted an online survey study (N = 157; 130 women, 25 men, 2 divers) among professional nurses in Germany (spring 2021) to test the derived items and subscales concerning interactive work, which resulted in a 4-factor model that was verified with confirmatory factor analysis (CFA). The survey further captured additional information on established constructs concerning job-related well-being (e.g., burn out, meaningfulness), job characteristics (e.g., work interruptions, time pressure) and individual resources (coping strategies) that are supposed to correlate with interactive work demand scales for nurses (IWDS-N), to determine the quantitative nature of their relations. The results show that the subscales of the IWDS-N have adverse effects on indicators of work-related well-being. Moreover, negative job characteristics, such as time pressure, are positively correlated with subscales of the IWDS-N and are therefore problem-focused coping strategies as an individual resource. The results emphasize that a multidimensional consideration of self-regulatory processes is useful to capture the subtle and complex nature of the interactive work demands of nurses. The current study is the first that developed a quantitative, multi-dimensional measure for interactive work demands, which can help make implicit demands in service work explicit.

Visual search in virtual 3D space: the relation of multiple targets and distractors.

Visual search and attentional alignment in 3D space are potentially modulated by information in unattended depth planes. The number of relevant and irrelevant items as well as their spatial relations may be regarded as factors which contribute to such effects. On a behavioral level, it might be different whether multiple distractors are presented in front of or behind target items. However, several studies revealed that attention cannot be restricted to a single depth plane. To further investigate this issue, two experiments were conducted. In the first experiment, participants searched for (multiple) targets in one depth plane, while non-target items (distractors) were simultaneously presented in this or another depth plane. In the second experiment, an additional spatial cue was presented with different validities to highlight the target position. Search durations were generally shorter when the search array contained two additional targets and were markedly longer when three distractors were displayed. The latter effect was most pronounced when a single target and three distractors coincided in the same depth plane and this effect persisted even when the target position was validly cued. The study reveals that the depth relation of target and distractor stimuli was more important than the absolute distance between these objects. Furthermore, the present findings suggest that within an attended depth plane, irrelevant information elicits strong interference. In sum, this study provides further evidence that allocation of attention is a flexible process which may be modulated by a variety of perceptual and cognitive factors.

Exploring the benefits and limitations of augmented reality for palletization.

Superimposing virtual visual information within the real world is referred to as augmented reality (AR). This technique becomes increasingly popular and due to technical advances can be applied to various purposes ranging from consumer entertainment to industrial use cases. Workplaces equipped with AR assistance-systems promise fast and accurate performance. Within the field of intralogistics, palletization constitutes a field of application which may benefit from guidance by AR. In the present investigation, participants performed a palletization task while they received instructions via three different devices (paper list, tablet, AR glasses). Performance data and subjective ratings were obtained. Participants subjectively preferred to work with the AR device. Number of errors was reduced while at the same time handling times were prolonged when the AR device was used. In all experimental conditions, performance improved in the course of the experiment. Least improvement was observed in the AR condition, which emphasizes that such applications allow decent performance without prior experience. Overall, the present results indicate that the utility of AR applications is limited when task demands are low. Such applications might be more useful in unclear and complex situations. Furthermore, AR possesses high hedonic qualities which may ease the integration of novel work processes.

Cognitive-motor interference in the wild: Assessing the effects of movement complexity on task switching using mobile EEG.

Adaptively changing between different tasks while in locomotion is a fundamental prerequisite of modern daily life. The cognitive processes underlying dual tasking have been investigated extensively using EEG. Due to technological restrictions, however, this was not possible for dual-task scenarios including locomotion. With new technological opportunities, this became possible and cognitive-motor interference can be studied, even in outside-the-lab environments. In the present study, participants carried out a cognitive-motor interference task as they responded to cued, auditory task-switch stimuli while performing locomotive tasks with increasing complexity (standing, walking, traversing an obstacle course). We observed increased subjective workload ratings as well as decreased behavioural performance for increased movement complexity and cognitive task difficulty. A higher movement load went along with a decrease of parietal P2, N2 and P3 amplitudes and frontal Theta power. A higher cognitive load, on the other hand, was reflected by decreased frontal CNV amplitudes. Additionally, a connectivity analysis using inter-site phase coherence revealed that higher movement as well as cognitive task difficulty had an impairing effect on fronto-parietal connectivity. In conclusion, subjective ratings, behavioural performance and electrophysiological results indicate that less cognitive resources were available to be deployed towards the execution of the cognitive task when in locomotion compared to standing still. Connectivity results also show a scarcity of attentional resources when switching a task during the highest movement complexity condition. Summarized, all findings indicate a central role of attentional control regarding cognitive-motor dual tasking and an inherent limitation of cognitive resources.

Allocation of attention in 3D space is adaptively modulated by relative position of target and distractor stimuli.

Allocation of attention across different depth planes is a prerequisite for visual selection in a three-dimensional environment. Previous research showed that participants successfully used stereoscopic depth information to focus their attention. This, however, does not mean that salient information from other depth planes is completely neglected. The present study investigated the question of whether competing visual information is differentially processed when displayed in a single depth plane or across two different depth planes. Moreover, it was of interest whether potential effects were further modulated by the items' relative spatial position (near or far). In three experiments participants performed a variant of the additional singleton paradigm. Targets were defined by stereoscopic depth information and as such appeared either in a near or far depth plane. Distractor stimuli were displayed in the same or in the opposed depth plane. The results consistently showed that visual selection was slower when target and distractor coincided within the same depth plane. There was no general advantage for targets presented in near or far depth planes. However, differential effects of target depth plane and the target-distractor relation were observed. Selection of near targets was more affected by distractors within the same depth plane while far targets were identified more slowly when the amount of information in closer depth planes increased. While attentional resources could not be exclusively centered to a distinct depth plane, the allocation of attention might be organized along an egocentric gradient through space and varies with the organization of the visual surrounding.

The influence of relevant and irrelevant stereoscopic depth cues: Depth information does not always capture attention.

Previous research reported ambiguous findings regarding the relationship of visuospatial attention and (stereoscopic) depth information. Some studies indicate that attention can be focused on a distinct depth plane, while other investigations revealed attentional capture from irrelevant items located in other, unattended depth planes. To evaluate whether task relevance of depth information modulates the deployment of attentional resources across depth planes, the additional singleton paradigm was adapted: Singletons defined by depth (i.e., displayed behind or in front of a central depth plane) or color (green against gray) were presented among neutral items and served as targets or (irrelevant) distractors. When participants were instructed to search for a color target, no attentional capture from irrelevant depth distractors was observed. In contrast, it took substantially longer to search for depth targets when an irrelevant distractor was presented simultaneously. Color distractors as well as depth distractors caused attentional capture, independent of the distractors' relative depth position (i.e., in front of or behind the target). However, slight differences in task performance were obtained depending on whether or not participants fixated within the target depth plane. Thus, the current findings indicate that attentional resources in general are uniformly distributed across different depth planes. Although task relevant depth singletons clearly affect the attentional system, this information might be processed subsequent to other stimulus features.

Review of Three-Dimensional Human-Computer Interaction with Focus on the Leap Motion Controller.

Modern hardware and software development has led to an evolution of user interfaces from command-line to natural user interfaces for virtual immersive environments. Gestures imitating real-world interaction tasks increasingly replace classical two-dimensional interfaces based on Windows/Icons/Menus/Pointers (WIMP) or touch metaphors. Thus, the purpose of this paper is to survey the state-of-the-art Human-Computer Interaction (HCI) techniques with a focus on the special field of three-dimensional interaction. This includes an overview of currently available interaction devices, their applications of usage and underlying methods for gesture design and recognition. Focus is on interfaces based on the Leap Motion Controller (LMC) and corresponding methods of gesture design and recognition. Further, a review of evaluation methods for the proposed natural user interfaces is given.

Surprising depth cue captures attention in visual search.

A substantial amount of evidence indicates that surprising events capture attention. The present study was primarily intended to investigate whether expectancy discrepant depth information also is able to capture attention immediately and-more specifically-whether cues that are relatively closer or farther differentially modulate behavior. For this purpose, participants had to identify one of two target letters in a search display. Stimulus positions were initially cued by uninformative placeholders. After half of the trials, the cue at the target position was suddenly and unexpectedly (critical trial) displayed closer to or farther from the observer. In line with previous research, both depth cues captured attention on their very first appearance. Performance in the critical trial was superior to the error rates in the trials without depth cue and was even above the performance in subsequent trials that included depth cue. This effect was only observed when the cue preceded the target by 400 ms. Using a shorter cue-stimulus interval of 100 ms, only a delayed improvement was observed, which denotes a typical feature of surprise capture. Moreover, response times were faster in trials comprising a depth cue, and this was already true for the critical trial. Apart from that, no other marked differences between near and far depth cues were observed. Therefore, the present results emphasize that surprising depth information indeed captures attention. However, in contrast to other perceptual tasks, search performance was not considerably influenced by relative position in depth.

The interconnection of mental fatigue and aging: An EEG study.

Mental fatigue, a state of reduced alertness and decreased overall performance due to prolonged cognitive activity, is a major cause for a large number of accidents in traffic and industry. Against the background of an aging workforce, the investigation of the interconnection of mental fatigue and aging is of great practical relevance. In the present study, a group of younger and a group of older adults performed a cognitive task for 3h. The experimental design also comprised breaks with various durations. Beside behavioral data, the spectral properties of the ongoing EEG with respect to time on task and breaks were analyzed. No differences between the age groups were found in behavior, but electrophysiological measures provide some evidence that older adults in our study were differentially affected by time on task. In the later course of the experiment modulations in frontal theta power became larger for older, compared to younger adults. This may indicate strain due to task demands, eventually resulting from the deployment of compensatory processes. Occipital alpha, which has been linked to internally oriented brain states, saturates faster in younger adults. It thus maybe, that especially the younger participants' performance deteriorated due to the monotonous nature of the task itself. Both mechanisms, an increased consumption of cognitive resources in older adults and a decrease of motivation in younger adults, could mask differences in performance decrements between the age groups due to mental fatigue.

Simple reaction time and size-distance integration in virtual 3D space.

Simple reaction time to visual stimuli depends on several stimulus properties. Recently, converging evidence showed that larger stimulus size evokes faster reactions and that this effect seemingly depends on the stimulus' perceived size rather than on physical stimulus properties. Size-distance scaling usually is regarded as the main functional mechanism underlying size perception. Yet, the role of stimulus depth (distance to a target) has often been neglected in previous studies. Hence, in the present investigation, stimuli were generated using stereo head mounted displays to manipulate stimulus depth. In Experiment 1, a large or small target was presented within the center of a reference plane, either in the same depth plane or displaced (near, far) while participants had to perform a simple reaction time task. At the same time, the target was modulated such that either retinal size was constant or variable across depth planes. In Experiments 2 and 3 the reference plane was shifted along with the target (blocked or on a trial-by-trial basis), while retinal size modulation was equal to Experiment 1. As expected, participants reacted faster to physically larger targets. Also Experiment 1 revealed faster reaction times for closer targets, while the commonly described connection between perceived size (i.e., size-distance scaling) was not apparent in any experiment. Thus, unlike past findings using a virtual three-dimensional task-setting (as induced by binocular disparity) reaction times are not affected by variations of perceived stimulus size.

Fast and Forceful: Modulation of Response Activation Induced by Shifts of Perceived Depth in Virtual 3D Space.

Reaction time (RT) can strongly be influenced by a number of stimulus properties. For instance, there was converging evidence that perceived size rather than physical (i.e., retinal) size constitutes a major determinant of RT. However, this view has recently been challenged since within a virtual three-dimensional (3D) environment retinal size modulation failed to influence RT. In order to further investigate this issue in the present experiments response force (RF) was recorded as a supplemental measure of response activation in simple reaction tasks. In two separate experiments participants' task was to react as fast as possible to the occurrence of a target located close to the observer or farther away while the offset between target locations was increased from Experiment 1 to Experiment 2. At the same time perceived target size (by varying the retinal size across depth planes) and target type (sphere vs. soccer ball) were modulated. Both experiments revealed faster and more forceful reactions when targets were presented closer to the observers. Perceived size and target type barely affected RT and RF in Experiment 1 but differentially affected both variables in Experiment 2. Thus, the present findings emphasize the usefulness of RF as a supplement to conventional RT measurement. On a behavioral level the results confirm that (at least) within virtual 3D space perceived object size neither strongly influences RT nor RF. Rather the relative position within egocentric (body-centered) space presumably indicates an object's behavioral relevance and consequently constitutes an important modulator of visual processing.

Frontal theta activity reflects distinct aspects of mental fatigue.

Longer lasting performance in cognitively demanding tasks leads to an exhaustion of cognitive resources and to a state commonly described as mental fatigue. More specifically, the allocation and focusing of attention become less efficient with time on task. Additionally, the selection of even simple responses becomes more error prone. With respect to the recorded EEG, mental fatigue has been reported to be associated with an increase in frontal theta and frontal and occipital alpha activity. The present study focused on the time course of changes in behavior and in the EEG to characterize fatigue-related processes. Participants performed a spatial stimulus-response-compatibility task in eight blocks for an overall duration of 4h. Error rates increased continuously with time on task. Total alpha power was larger at the end compared to the beginning of the experiment. However, alpha power increased rapidly and reached its maximal amplitude already after 1h, whereas frontal theta showed a continuous increase with time on task, possibly related to increased effort to keep the performance level high. Time frequency analyses revealed power changes in the theta band induced by task relevant information that might be assigned to a drain of executive control capacities. Thus, frontal theta turned out to be a reliable marker of distinct changes in cognitive processing with increasing fatigue.

Evaluation of the leap motion controller as a new contact-free pointing device.

This paper presents a Fitts' law-based analysis of the user's performance in selection tasks with the Leap Motion Controller compared with a standard mouse device. The Leap Motion Controller (LMC) is a new contact-free input system for gesture-based human-computer interaction with declared sub-millimeter accuracy. Up to this point, there has hardly been any systematic evaluation of this new system available. With an error rate of 7.8% for the LMC and 2.8% for the mouse device, movement times twice as large as for a mouse device and high overall effort ratings, the Leap Motion Controller's performance as an input device for everyday generic computer pointing tasks is rather limited, at least with regard to the selection recognition provided by the LMC.