Dense 3D pressure discomfort threshold (PDT) map of the human head, face and neck: A new method for mapping human sensitivity.

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.

Seat pitch and comfort of a staggered seat configuration.

BACKGROUND: Staggered seats are a solution for the Flying-V aircraft, where the cabin's longitudinal axis has a 26 degrees angle with respect to the direction of flight, to compensate for an otherwise oblique sitting position. However, little is known on acceptable pitches in this staggered configuration. OBJECTIVE: The goal of this research is to evaluate the comfort of different pitches for seats that are staggered relative to the cabin's longitudinal axis. METHODS: Two rows of staggered seats are positioned at three different pitches (27, 29 and 31 inches). 53 participants were seated in each setup. For each, a questionnaire was completed including questions on comfort and discomfort, top view photos were taken to analyse postures and physical dimensions were recorded to define passengers' space. RESULTS: Comfort as well as discomfort were significantly different for the three setups. The comfort at 27 inches was seen as unacceptably low. The 29 and 31-inch configurations showed to result in acceptable levels of comfort, comparable to higher-end seating layouts. There were very little complaints about space in lateral direction (elbow and seat width), showing the advantage of having your won armrest and shoulder space in the staggered configuration. Interesting was that at larger pitches more complaints were found for the seat characteristics, probably in the shorter pitch the other discomfort was overruling this. CONCLUSION: The 26-degree staggered configuration offers improvements in shoulder- and elbow-space. The results for the 29- and 31-inch are expected to allow enough design freedom for further exploration of such a configuration for the Flying-V cabin interior.

Concept evaluation of a new aircraft passenger privacy bubble using virtual prototyping: A Human-Centered Design framework.

BACKGROUND: The Human-Centered Design methodology advocates VR prototyping, as an effective tool to evaluate concepts in a cost-efficient, time-saving way. It is the question of whether it works in the development of a product intended to increase privacy while flying. OBJECTIVE: The current study aims at the application of virtual reality on the evaluation of a new privacy bubble called PRIVA for the passenger cabin. METHODS: An interactive VR was created and aligned with the HTC VIVE headset. 40 participants took part in the experiment as well as in the post-experiment survey. RESULTS: The concept was in overall, desirable as it was perceived to be more private, comfortable, satisfactory, effective, and appealing to participants compared to the current seat experiences. It was also perceived as more satisfactory with regards to the activities. CONCLUSIONS: The VR was effective, although there are limitations, the product seems promising and should be developed further.

Perceived onboard passengers' experience: Flight attendants' point of view.

BACKGROUND: Cabin research is mostly based on passenger reports. However, it is also important to consider the perceptions of flight attendants as onboard service providers, since they can convey a complementary view shedding light on important aspects related to passenger experience. OBJECTIVE: This study seeks to analyze flight-attendants' perception regarding passengers' inflight activities and experience. METHODS: Twenty-eight flight attendants were interviewed on more than twenty-three inflight activities that were extracted from a brainstorming session. A survey was designed based on these activities and was distributed to flight attendants. RESULTS: Overall, flight attendants perceived the activities 'resting/relaxing', 'sleeping' and 'using the restroom' for comfort as the most important activities to passengers, while activities 'talking to neighbors' and 'thinking and observing' were the least important ones. Interesting was the fact that flight attendants scored satisfaction of some activities higher then passengers. CONCLUSIONS: Flight attendants had a similar idea on importance of activities of passengers, but they valued some activities as more satisfactory.

Human behaviour should be recorded in (dis)comfort research.

(Dis)comfort research that has no information on behaviour of the participants can be considered as incomplete, as major influencing factors could be missed. For (dis)comfort research it is important to capture factors such as context, task/activity, posture, movement, (distracting) stimuli and time, as these factors have influence on the experienced (dis)comfort. Recording the behaviour allows for better evaluation of and comparison between studies, contributing to an increase of scientific knowledge on (dis)comfort.

Implementing spring-foam technology to design a lightweight and comfortable aircraft seat-pan.

This paper investigates whether spring-foam technology in an aircraft seat-pan can reduce weight and at the same time provide equal or better comfort. Firstly, through literature studies and using an iterative design process a prototype seat-pan was designed and developed using spring-foam technology. The (dis)comfort of this seat was compared with a standard aircraft seat-pan. Twenty two participants were asked to sit in each seat for 90 min, completing a questionnaire every 15 min. At the end of each seating session pressure map recordings were made of the seat-pans. The results showed that the prototype seat-pan has on average a significantly higher comfort for the first 30 min and at a 60 min recording than the standard seat-pan. The discomfort and long term comfort were not significantly influenced. The pressure distribution on the prototype seat-pan was significantly closer to an ideal pressure distribution than a conventional seat-pan. In addition, the prototype seat-pan had a significantly larger contact area and lower average pressure. The seat-cushion weighs 20% less than the conventional seat-cushion. The study indicates that a seat-pan design using spring-foam technology can be lighter and more comfortable than conventional foam cushion materials. It is recommended to optimize the prototype seat further and conduct long term (dis)comfort studies with a broader variation in subjects' age.

A system to measure seat-human interaction parameters which might be comfort relevant.

In this paper a measurement tool is described and tested to evaluate the characteristics of different elements of a seat. Many studies report a relationship between discomfort and pressure distribution, but it is unknown what exactly is happening in the interaction. The purpose of this study is to present a measuring device, which records the comfort relevant seat parameters pressure and elongation while loading a seat. The results of the study, including the repeatability, reproducibility and detectability show that the measurement method is appropriate for our purpose, although the reproducibility has to be improved by operator experience or by a more intuitive assembling of the measurement setup. An application example illustrates that the interaction of the seat components highly affect the resulting comfort relevant parameters. The question is whether this objectively recorded differences are also experienced by seat occupants, which is interesting to study in future research.

Neck posture and muscle activity in a reclined business class aircraft seat watching IFE with and without head support.

The purpose of this study is to research if a headrest benefits the comfort of the passenger and lowers muscle activity in the neck when sitting in a reclined (slouched) posture while watching in flight entertainment (IFE) in an aircraft business class seat. No significant differences in muscle activity in the musculus sternocleidomastoid and musculus trapezius pars descendant were found between the conditions with headrest and without headrest. A significant difference in expected comfort rating was found. Subjects indicated they expect to experience more comfort with a headrest when watching IFE for a duration of two movies during a long-haul flight. This study also found a significant difference in posture. In the condition without headrest the head was more upright compared to the condition with headrest. The lack of significant difference in muscle activity and the significant difference in posture may indicate that humans tend to look for a head position that is neutral, in the sense of minimal muscle effort. This study shows that the use of a headrest may benefit the comfort experience of the passenger during flight. However, further research is necessary on the design of the headrest and the long-term effects of head support on comfort, discomfort, muscle activity and fatigue for watching IFE in a slouched posture.

Thirty years of anthropometric changes relevant to the width and depth of transportation seating spaces, present and future.

This paper reports the results of an investigation into changes in body shape anthropometry over the past several decades and discusses the impact of those changes on seating in transport, especially airliners. Changes in some body shape dimensions were confirmed in a sample of students at TU Delft; several of the changes, e.g. hip breadth, seated, are relevant to the ongoing design of seating. No change in buttock knee length was observed. The fit between current user anthropometry and current airline seat design, especially regarding seat width, was investigated. A comparison of the average current seat breadth with global anthropometric data suggests that accommodation may be problematic, with less than optimal width for passengers' shoulder and elbow widths.

Clinimetric properties of the Nociception Coma Scale (-Revised): A systematic review.

The Nociception Coma Scale is a nociception behaviour observation tool, developed specifically for patients with disorders of consciousness (DOC) due to (acquired) brain injury. Over the years, the clinimetric properties of the NCS and its revised version (NCS-R) have been assessed, but no formal summary of these properties has been made. Therefore, we performed a systematic review on the clinimetric properties (i.e. reliability, validity, responsiveness and interpretability) of the NCS(-R). We systematically searched CENTRAL, CINAHL, Embase, PsycInfo and Web of Science until August 2015. Two reviewers independently selected the clinimetric studies and extracted data with a structured form. Included studies were appraised on quality with the COSMIN checklist. Eight studies were found eligible and were appraised with the COSMIN checklist. Although nearly all studies lacked sample size calculation, and were executed by the same group of authors, the methodological quality ranged from fair to excellent. Important aspects of reliability, construct validity and responsiveness have been studied in depth and with sufficient methodological quality. The overview of clinimetric properties in this study shows that the NCS and NCS-R are both valid and useful instruments to assess nociceptive behaviour in DOC patients. The studies provide guidance for the choice in NCS-R cut-off value for possible pain treatment and cautions awareness of interprofessional differences in NCS-R measurements. SIGNIFICANCE: This systematic review provides a structured overview of the clinimetric properties of the Nociception Coma Scale (-Revised) and provides insights for a solid evidence-based nociception behaviour assessment and treatment plan.

The effect of human-mattress interface's temperature on perceived thermal comfort.

In recent years, methods that allow for an objective evaluation of perceived comfort, in terms of postural, physiological, cognitive and environmental comfort, have received a great deal of attention from researchers. This paper focuses on one of the factors that influences physiological comfort perception: the temperature difference between users and the objects with which they interact. The first aim is to create a measuring system that does not affect the perceived comfort during the temperatures' acquisition. The main aim is to evaluate how the temperature at the human-mattress interface can affect the level of perceived comfort. A foam mattress has been used for testing in order to take into account the entire back part of the human body. The temperature at the interface was registered by fourteen 100 Ohm Platinum RTDs (Resistance Temperature Detectors) placed on the mattress under the trunk, the shoulders, the buttocks, the legs, the thighs, the arms and the forearms of the test subject. 29 subjects participated in a comfort test in a humidity controlled environment. The test protocol involved: dress-code, anthropometric-based positioning on mattress, environment temperature measuring and an acclimatization time before the test. At the end of each test, each of the test subject's thermal sensations and the level of comfort perception were evaluated using the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) scale. The data analyses concerned, in the first instance, correlations between the temperature at the interface and comfort levels of the different parts of the body. Then the same analyses were performed independently of the body parts being considered. The results demonstrated that there was no strong correlation among the studied variables and that the total increase of temperature at interface is associated with a reduction in comfort.

Don't forget time in environmental design1.

This paper discusses the importance of including time in environmental design and the challenges facing environmental design now and in the future. Research shows that important factors for studying the effects of environments are time, body movement, control and sensory variability. There are many ways to incorporate time into the design and it is dependent on the type of environmental design. Research also suggests that discomfort in restrictive environments, e.g., in an airplane or automobile are strongly related long periods of inactivity and lack of sensory stimulation. Research also suggests that office workers' health risks are in a large part due to restrictive movement, training inefficiencies, and lack of variation found in the environment. A challenge is how to incorporate stimulating activities and variation into restrictive environments. Another challenge is the cost versus benefit of designing comfortable and healthy environments. Will comfort standards be accomplished through volunteer compliance or is it necessary to push for compliance through legal requirements, standards and regulations? Is it time to consider reducing discomfort as a necessity and apply what research has suggested, i.e., that variation and movement over time in interior environments promotes well-being and productivity? Is it time to accept the results of research and apply the findings to the designs and practice of environmental design?

Modeling the relationship between the environment and human experiences.

Within this special issue, different aspects of the environment are studied: aspects that are distant from the human body, close to the body and touching the human body. Consequently, different human senses are involved in these studies as well as the different consequences and effects on the brain and human behaviour. This special issue also highlights many remaining questions about the effects and relationships between environments and human beings and the need for more studies and research. In particular, future studies are needed that address long-term effects and the effects of the combinations of elements which provide comfort or discomfort.

Interior effects on comfort in healthcare waiting areas.

BACKGROUND: This study compared the effects of pre-experience and expectations on participant comfort upon waking, arrival to, and after an appointment, as well as the assessment of properly placed Feng Shui elements in three healthcare waiting rooms. METHODS: Participants assessed comfort levels using self-report surveys. The researcher conducted 'intention interviews' with each doctor to assess the goals of each waiting area design, and conducted a Feng Shui assessment of each waiting area for properly placed Feng Shui elements. RESULTS: The waiting area designed by the Feng Shui expert rated 'most comfortable', followed by the waiting area design by a doctor, and the lowest comfort rating for the conventional waiting room design. Results show a sufficiently strong effect to warrant further research. CONCLUSIONS: Awareness of the external environment, paired with pre-experience and expectation, influences comfort for people over time. Fostering and encouraging a holistic approach to comfort utilizing eastern and western concepts and ergonomic principles creates a sense of "placeness" and balance in the design for comfort in built environments. This is new research information on the influences of the comfort experience over time, to include pre-experience, expectations and the placement of elements in the external environment.

Application of ideal pressure distribution in development process of automobile seats.

BACKGROUND: In designing a car seat the ideal pressure distribution is important as it is the largest contact surface between the human and the car. Because of obstacles hindering a more general application of the ideal pressure distribution in seating design, multidimensional measuring techniques are necessary with extensive user tests. OBJECTIVE: The objective of this study is to apply and integrate the knowledge about the ideal pressure distribution in the seat design process for a car manufacturer in an efficient way. METHODS: Ideal pressure distribution was combined with pressure measurement, in this case pressure mats. In order to integrate this theoretical knowledge of seating comfort in the seat development process for a car manufacturer a special user interface was defined and developed. RESULTS: The mapping of the measured pressure distribution in real-time and accurately scaled to actual seats during test setups directly lead to design implications for seat design even during the test situation. Detailed analysis of the subject's feedback was correlated with objective measurements of the subject's pressure distribution in real time. Therefore existing seating characteristics were taken into account as well. CONCLUSIONS: A user interface can incorporate theoretical and validated 'state of the art' models of comfort. Consequently, this information can reduce extensive testing and lead to more detailed results in a shorter time period.

Exploring the design of a lightweight, sustainable and comfortable aircraft seat.

BACKGROUND: Making a lightweight seat that is also comfortable can be contradictory because usually comfort improvement means adding a feature (e.g. headrest, adjustable lumbar support, movable armrests, integrated massage systems, etc.), which makes seats heavier. OBJECTIVE: This paper explores the design of an economy class aircraft seat that aims to be lightweight, comfortable and sustainable. METHODS: Theory about comfort in seats, ergonomics, lightweight design, Biomimicry and Cradle to cradle was studied and resulted in a list of requirements that the new seat should satisfy. RESULTS: The design process resulted in a new seat that is 36% lighter than the reference seat, which showed that a significant weight reduction can be achieved. This was completed by re-designing the backrest and seat pan and integrating their functions into a reduced number of parts. Apart from the weight reduction that helps in reducing the airplane's environmental impact, the seat also satisfies most of the other sustainability requirements such as the use of recyclable materials, design for disassembly, easy to repair. A user test compared the new seat with a premium economy class aircraft seat and the level of comfort was similar. CONCLUSIONS: Strong points of the new design were identified such as the lumbar support and the cushioning material, as well as shortcomings on which the seat needs to be improved, like the seat pan length and the first impression. Long term comfort tests are still needed as the seat is meant for long-haul flights.

An estimation of the human head, neck and back contour in an aircraft seat.

BACKGROUND: Passenger comfort is a key variable in user acceptance of transportation systems. The back rest of a seat is of importance part in this experience. In designing a backrest, information of the human contour is useful as the product can be formed following this contour. The question is whether there is too much variation due to variety in tasks or in human anthropometry to design a back rest. OBJECTIVE: The research question is whether anthropometric properties and the performed activity have an influence on the back contour of a person. METHODS: The head, neck and back contour of a human sitting in an aircraft seat are estimated by using a kyphometer. In total 46 subjects are measured in two different chairs, when performing two different activities. RESULTS: This research indicates that the maximum variation of the contours occur on the upper back, neck and head. These parts are more bended forward when using a laptop compared with watching IFE. By dividing the data in groups, based on buttock-top of head distance, the height at which significant differences between the groups occur was determined. For one seat 400 mm above the seat pan a significant difference was found and for the other seat this was 420 mm above the seat pan. CONCLUSIONS: Differences in back contour started to appear above 400 mm vertical distance from the seat pan, which means that the design of a seat should facilitate this variation.

Improvement of the Stolwijk model with regard to clothing, thermal sensation and skin temperature.

BACKGROUND: The original Stolwijk model is not equipped with clothing, thermal sensation, comfort indices, individual characteristics and performance loss models. OBJECTIVE: This study attempts to modify the model to include clothing, thermal sensation as well as the calculation of the percentage of dissatisfied as a result of general discomfort. The model is useful for the evaluation of thermal comfort in the built environment by professionals. METHODS: Methods described in literature with regard of clothing, the research of Fiala as well as some in the literature recommended and validated adjustments, to improve the simulation of the skin temperature per body segment, are implemented in the here assembled Stolwijk computer model. Finally, for verification of the above adjustments, the model was compared with experiments conducted in the field of thermal sensation at various levels of temperature change. RESULTS: By improving the simulation of the skin temperature per body segment and by adding clothing and thermal sensation, suitable for the assessment of steady state and transient thermal conditions, and fixed with this the percentage of dissatisfied, the scope of the Stolwijk model has become larger than it was before. CONCLUSION: On the basis of the calculations and the experimental results, it was concluded that the adjusted Stolwijk model was suitable for the simulation of the thermal sensation under steady state and transient thermal conditions.

Attitudes towards personal and shared space during the flight.

BACKGROUND: Aircraft passenger comfort experience was previously defined based on its underlying thematic components representing passengers' perception of the environmental elements and their link to their concerns. OBJECTIVE: This paper aims to 1) identify aircraft passengers' attitudes towards their personal and shared space in the cabin environment during the flight which are linked to their comfort experience and 2) highlight passenger concerns associated with those attitudes. METHOD: A sample involving 16 participants was conducted, collecting full accounts of their real-time flight experiences onboard commercial aircrafts, using questionnaires. RESULTS: Four types of attitudes were identified in reaction to participants' personal and shared space during the flight. Those were described as adjust, avoid, approach, and shield. Passengers' concerns associated with those attitudes were respectively: control, privacy, connectedness and tolerance. CONCLUSIONS: It is concluded that passenger comfort can be improved once the identified concerns and attitudes are addressed in the design of the aircraft seat and interior. Design recommendations are provided accordingly.

Functional customization: Value creation by individual storage elements in the car interior.

BACKGROUND: Mobility demands change due to differing life stages of car owners. Car sharing and retail markets seldom offer a possibility for customization by the user in contrast to the freedom of choice of an initial owner of a car. OBJECTIVE: The value creation of functional customization is investigated. Prior to a test with a concept design, different use case scenarios of car drivers are identified regarding the preferred storage location of their personal belongings in different situations. METHODS: A study with 70 subjects was conducted in order to evaluate the value added by functional customization. Storage habits of users were investigated in general and in relation to a concept design offering the possibility for flexible storage. RESULTS: Smartphones, supplies, beverages and wallets were the most relevant belongings in all driving situations (commuting, leisure, vacation and special occasions) complemented by sports equipment. Smartphones and other valuables are stored within reach and sight of the user. The emotional responses, recorded before and after the test, subdivided in attraction, hope and joy indicated positive feedback. CONCLUSIONS: The ease of use and the design proved to be crucial product characteristics of individually adaptable storage solutions. Positive emotions are contributing factors for a user's purchasing decision.