To establish guidelines for sleeping space in vehicles, the sleeping postures of 189 participants are studied, 105 of them were asked to take the position in which they fall asleep and 84 have been asked to assume the position in which they lie most of the time. Seven percent slept on the stomach, 19% on the back and 74% on the side and 49% slept on the side with both legs flexed. For all participants a bed size of 200 × 90 cm will do. It is discussed that for one night while travelling a bed size of 171 × 76 cm might be sufficient as it results in a reasonably good sleep according to another study and in almost half of the cases in this study people sleep on the side with both legs folded. Apart from the sleeping space for a good sleep, attention is needed for a dark environment with a good temperature and relative silence.@en

To reduce the weight of a seat of a city car (A-segment), a new car seat was developed. First, a questionnaire was used to define the main functions the occupants prefer to have in the seat. The reclining and forward afterwards movement of the seat were seen as most important. Based on this outcome a seat was developed with a new reclining mechanism and a weight reduction of 4 kg. This seat was tested by 30 participants and compared with a bench mark seat of the Toyota Aygo. It was clear that comfort testing is difficult comparing a full developed car seat with a prototype, which still needs development. Nevertheless, the comfort was comparable between the two seats and the shoulder space of the new seat was appreciated. The conclusion is that it is possible to develop a more light weight car seat, which has the main features preferred by occupants, but further development is needed.

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According to the literature, there is a significant correlation be-tween the total experienced discomfort while seated and the maximum values of discomfort around the area of the side bolsters. However, there is not much research on bolster design. In this study pressure distribution between the human body and a bolster is recorded to see if further optimization of bolsters is possible. The study shows that the lower rib generates more pres-sure around 30-35 cm above the seat pan and it shows that there is much in-terindividual variation. In this project a new smart mechanism in the bolster was developed, which can adapt to different shapes, but it is also clear that pressure sensors in the bolster are preferable to be able to adapt to the large variation between humans.@en

Automated driving frees users from the task of driving, allowing them to engage in new activities. Using keywords related to Non-Driving-Related Activities (NDRAs) and automated vehicles (and their variants), with reference to the Society of Automotive Engineers (SAE) levels 3, 4, and 5, the authors identified 2430 studies from various databases and sources. Of these, 47 were included in this study, with 39 included in the meta-analysis. The meta-analysis of the included studies shows a positive correlation between automation levels and the diversity of NDRAs. Communication and interaction with passengers are the most common activities, followed by media consumption, rest, and relaxation. Food and drink consumption slightly surpasses working and productivity, while personal habits and hygiene are less prioritized. Although some users still value vehicle monitoring, this need decreases with higher automation levels. Key activities such as communication, laptop use, and sleeping are highlighted as significant benefits of automation, as users transition away from situational awareness and are able to perform cognitively intensive tasks. The review also addresses potential design implications to support these NDRAs and discusses related regulatory challenges.@en

BACKGROUND:
In vehicles there is often limited space for seats. This might mean that reclining the back rest reduces the legroom. The second row in a cargo van has this problem and in this limited space an upright seat and a reclined seat with less legroom was developed and tested.

OBJECTIVE:
The research question of this study is: Does a reclined backrest with less leg room result in the same comfort and/or discomfort as an upright backrest with more leg room?

METHODS:
Twenty participants are asked to sit 45 minutes in the upright seat with 8 cm more legroom and 45 minutes in the reclined seat. Ten participants started in the upright seat and ten in the reclined. Participants had to complete a comfort and discomfort questionnaire every 15 minutes and a qualitative interview was conducted after experiencing both seats.

RESULTS:
For comfort no statistically significant differences were found between both seats. For discomfort statistically significant differences were found where discomfort was lower in the reclined seat. Half of the participants preferred the upright and half the reclined seat. The interviews showed that the reclined position was more related to relaxation.

CONCLUSIONS:
This study indicates that a more reclined back rest results in less discomfort, but that does not lead to a clear preference of participants. The reclined position is associated with relaxing, and this study indicates that for the relaxing state the more reclined seat is preferred. For more active situations the upright posture seems better.@en

Turboprop aircraft are a useful alternative to reduce CO2 emissions, but they have a higher noise and vibration level compared to turbojets. We investigated how passengers perceived noise and vibration during two turboprop flights in an ATR72.In general, noise as assessed as slightly loud and slightly annoying, but became less noisy and more comfortable over time. Subjects evaluated the vibration as rather comfortable, but the perception of vibration varied for different body areas. Discomfort of vibration decreased. If noise sensitivity is added to these analyses, changes over time largely disappeared showing the complex interaction between characteristics of the person and the environment. In summary, the rather negative evaluation of noise and vibration could be the factors why people decide not to fly with turboprop aircrafts. The development of turboprop aircraft with less noise and vibration remains important so that this more sustainable aircraft type is competitive. @en

Taking a nap is a welcome pastime in vehicles such as trains, airplanes, and cars. Flat sleeping cannot always be facilitated because of space and economic constraints, but a larger backrest recline angle is associated with better sleep quality. To define the best and the worst comfort experience and sleep comfort in these settings, and to offer design guidelines to practitioners, six backrest recline angles were compared regarding overall comfort and sleep comfort. The backrest recline angles ranged from 110 to 150 degrees, and 180 degrees was added as a reference. 16 participants were invited to sleep for a duration of 90 min. in each condition. Overall comfort and sleep comfort significantly improve in conditions higher than 120 degrees. Local discomfort is rated relatively low in all angles, but in comparison, people experience high discomfort in the neck, lower back, and lower leg region while in the 110 and 120 degrees condition. It is concluded that in the bigger recline angles the napping comfort experience is higher, with a minimum advised angle of 130 degrees.@en

Turboprop aircraft should be improved as they are more environmentally friendly aircraft compared to turbojet aircraft but noise and vibration are often too high for passengers. A simple and uncomplicated way to carry out experiments is using a demonstrator. To determine whether the demonstrator represents the reality, it must be validated. In this project, real flights were first conducted in a turboprop aircraft. During two 70-minute flights, 94 subjects answered questions about symptoms, mood or comfort levels related to noise and vibration, among other things. In the next step, investigations will be carried out in the demonstrator under the same conditions as the real flights. Both results will be compared with each other. If the data from the demonstrator corresponds to that of the real flights, the demonstrator is considered to have been successfully validated. The requirement for this is that the demonstrator data lies within the confidence intervals of the results from the real flights. The aim is to validate a full-scale on-ground demonstrator of a regional turboprop aircraft cabin that will be used for multiple tests like subject tests and comfort evaluation, composite materials and structures, systems and energy consumption.

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When designing wearables that interface with the human head, face and neck, designers and engineers consider human senses, ergonomics and comfort. A dense 3D pressure discomfort threshold map could be helpful, but does not exist yet. Differences in pressure discomfort threshold for areas of the head, neck and face were recorded, to create a 3D pressure discomfort threshold map.

Between 126 and 146 landmarks were placed on the left side of the head, face and neck of twenty-eight healthy participants (gender balanced). The positions of the landmarks were specified using an EEG 10–20 system-based landmark-grid on the head and a self-developed grid on the face and neck. A 3D scan was made to capture the head geometry and landmark coordinates. In a randomised order, pressure was applied on each landmark with a force gauge until the participant indicated experiencing discomfort. By interpolating all collected pressure discomfort thresholds based on their corresponding 3D coordinates, a dense 3D pressure discomfort threshold map was made.

A relatively low-pressure discomfort threshold was found in areas around the nose, neck front, mouth, chin-jaw, cheek and cheekbone, possibly due to the proximate or direct location of nerves, blood veins and soft (muscular) tissue. Medium pressure discomfort was found in the neck back, forehead and temple regions. High pressure discomfort threshold was found in the back of the head and scalp, where skin is relatively thin and closely supported by bone, making these regions interesting for mounting or resting head, face and neck related equipment upon.@en

The sleep quality and (dis)comfort sitting upright was studied among 40 participants who took a nap at home. They were asked to take a nap at 17:00h on three consecutive days. The backrest had to be at a different angle every day: upright, reclined and more reclined. They were asked to record the backrest angle of the three positions and report the length of the sleep, the sleep quality, comfort and discomfort and influence of other factors each during each nap. From the 120 cases (3 conditions, 40 participants), the cases where participants were not able to sleep had an average backrest angle of 110˚, which was significantly different from the cases where participants were able to sleep, who had an average backrest angle of 118˚. The scores in the more upright position (<110˚) resulted in significantly more discomfort and a lower sleep quality than in the reclined positions (>123˚). As the conditions were arranged by the participants, there was much variation in outcomes. Therefore, future research under more standardised conditions is recommended.@en

For the sake of energy and cost savings, it is sometimes necessary to maintain the indoor climate in a room at conditions that deviate from optimal thermal comfort. More important than thermal sensation is how a change in conditions will affect the thermal acceptability of a space and whether the percentage of people who are (dis)satisfied with the environment will change with regard of the acceptability. The aim of this technical note and arithmetic study is to find out to what extent the thermal indoor climate can be assessed on the basis of thermal
acceptability, in addition to the thermal (dis)satisfied, by making use of research that has already been carried out. In addition to the relationship between the percentage of (dis)satisfied and acceptability, attention is paid to how this result relates to current Dutch government building regulations. The paper concerns a proposal for the assessment of thermal indoor climate based on the thermal acceptability, in addition to the thermal (dis)satisfied.@en

Passengers' comfort experience during flights is important in choosing their flights. The focus of this study is passengers’ perceived comfort in different climbing angles during ascent. Twenty-six participants were invited to experience three inclination angles including 3°, 14° and 18° in a Boeing 737 cabin. The angle of 3° was used to simulate cruising stage and the other two were used to simulate different climbing angles. Participants experienced each setting for 20 min where the perceived comfort, their heart rate variability(HRV), and their body contact pressure values on the backrest and seat pan were recorded with questionnaires, HRV bands and pressure mats respectively. The results indicate a preference of 14° inclination angle resembling the cruising angle (3°) and having the slowest moving speed of the center of pressure (COP) on both the backrest and seat pan.

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Wearables are used to recognize human activities in various applications. However, there is limited evidence on the comfort feelings in using wearables, which is crucial for the adoption and long-term engagement of users in those applications. In this paper, we propose the concept of comfort wearables in the context of in-flight posture recognition. A comfort wearable and a tight-fit version, using identical hardware and software architecture, were prototyped and tested by 35 participants in a Boeing 737 cabin. During the usage of each wearable, participants were asked to perform seven frequently observed in-flight sitting postures and report their overall comfort/discomfort afterwards. A multilayer perceptron neural network was used to classify those activities. Experiment results indicated that participants appreciated the comfort wearable, rating it with significantly higher comfort scores and lower discomfort scores. Cross-validation results also revealed that using the comfort wearable achieved even better accuracy (74.8%) than using the tight-fit wearable (65.8%) in posture recognition. Outcomes of the study demonstrate that ergonomic design and technical accuracy are not competing factors in the wearable design and highlight the opportunities for designing and using comfort wearables in broader contexts.@en

BACKGROUND: A valid distribution of key anthropometric parameters among participants is often a perquisite of ergonomics research. OBJECTIVE: In this paper, we investigated the accuracy of self-reported stature and body mass of the population in the Netherlands. METHODS: Data from 4 experiments was synthesized where in each experiment, participants self-reported their stature and body mass prior to being measured, of which they were not notified before. RESULTS: Statistical analysis of 249 records indicated that on average, participants overreported their stature by 1.31 cm and underreported their mass by 1.45 kg. This is especially true for people with a BMI ≥ 25. CONCLUSION: Two models were proposed to adjust the self-reported stature and body mass for ergonomic researchers in a survey or recruitment. Limitations in using the models are highlighted as well.

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