International Journal of Human Factors and Ergonomics (8 papers in press)
Human-factors lessons from a longitudinal, in-vivo study of operations at a low-cost carrier
by Simon A. Bennett
Abstract: Apart from Ginnetts (1990) seminal paper, there are few in vivo studies of flight operations generally, and of crew resource management (CRM) specifically. This paper presents an ethnographic account of fifty-six intra-European flights and an in-house CRM training course. The subject airline provided the author (referred to as the observer) with an airside pass. At the subject airline, pilots and cabin crew are jointly trained in CRM. It was found that (1) pilot-cabin crew teams functioned effectively under a variety of conditions, (2) safety-critical flight-deck routines, such as programming the flight-management computer, were subject to interruption, (3) pilots and cabin crewmembers provided emotional support to colleagues which promoted efficiency and effectiveness, and (4) pilots who had not operated for a considerable time could be rostered to operate services to challenging airfields. The findings suggested that (1) joint training of pilots and cabin crew in CRM delivers safety and efficiency benefits, (2) benefits would accrue from expanding the CRM training catchment to include key ground personnel, (3) services to challenging airfields must be crewed by pilots who operate regularly. The study showed that despite the passage of time and evolution of the industry, the observations made by Ginnett twenty-years ago still hold. It is recommended that the industry develops a complete understanding of the lived-reality of flight operations. This can only be achieved through candid in-vivo studies of ground-schools and flight-deck/cabin labour.
Keywords: Crew resource management; safety; ethnography; inductive; lessons.
Flexible office, flexible working? A post-relocation study on how and why university employees use a combi-office for their activities at hand.
by Antonio Cobaleda Cordero, Maral Babapour, I.C. MariAnne Karlsson
Abstract: This study reports on a group of university employees, six months after their relocation from cell-offices into a combi-office. Data from interviews, observations and planning documentation was collected to gain an in-depth understanding of how employees use their office landscape and why. Activity Theory was taken as framework for the analysis. The findings show that the new office landscape was perceived to be more flexible and capable of supporting employees activities. The overall occupancy was low and backup spaces, such as quiet rooms, were barely used. Matches and mismatches between the employees, their activities and the office were identified that explain the occupancy rates and why spaces such as quiet rooms were unpopular spaces. This paper contributes with rich detail on the use of a flexible office landscape in a university context and shows the usefulness of Activity Theory in the study of employee-office interactions.
Keywords: office use; office landscape; flexible office; flexible working; combi-office; spatial attributes; Activity Theory; post-relocation study.
Preserving Auditory Situation Awareness in Headphone-Distracted Persons
by Keenan May, Bruce Walker
Abstract: Auditory distraction due to portable audio devices poses a hazard for pedestrians and cyclists. To explore solutions, auditory situation awareness (SA) was assessed within a simulated auditory roadway environment rendered via speakers. Participants' ability to report the presence and current/future location of vehicles was measured. The key manipulation was whether concurrently-presented distracting music was spatialized. Also manipulated were two common safety measures that impact spatialization quality: whether bone or air conduction headphones were used, and whether sounds were presented in one or both ears. Spatialization of distractors improved vehicle localization in some conditions, as did presenting to one ear and via bone conduction. In Experiment 2, distractors were spatialized adaptively, to be diametrically opposed to targets. This intervention improved localization without increasing workload. Results suggest that static or adaptive spatialization should be considered as a safety measure for sound presentation in computing systems used by cyclists or pedestrians.
Keywords: Safety; headphones; situation awareness; bone conduction; bicycling; roadway; hazard avoidance; spatial audio.
VEHand: an in-vehicle information system to improve driving performance in an unfamiliar traffic regulation
by Hasan J. Alyamani, Manolya Kavakli, Stephen Smith
Abstract: Driving under unfamiliar traffic regulations (UFTR) is associated with an increased number of traffic accidents. To drive safely in such conditions, drivers need to adapt their prior knowledge to a new driving situation. This ability is called cognitive flexibility (CF). CF is influenced by the degree of handedness of the performer. The goal of this research was to develop a driving-assistance system that adapts the information it provides based on the handedness degree of drivers under UFTR. Two empirical studies were conducted in a driving simulator. The results of the first study indicated that left/mixed-handed drivers made significantly fewer errors that could be attributed to CF impairment than did strong right-handed drivers. Accordingly, we developed a driving-assistance system ('VEHand'), which provides drivers with useful feedback based on their handedness degree. The results of the second study indicated that VEHand significantly assisted strong-right handed drivers to correctly enter roundabouts and intersections.
Keywords: cognitive flexibility; driving performance; in-vehicle information system; IVIS; degree of handedness; driving simulator; unfamiliar traffic regulation; UFTR; roundabout; intersections.
Exploratory study on adequacy of upper extremity position during smartphone usage
by Han-Yeong Yun, Tae-Lim Yoon
Abstract: This study compared the effects of the prone, side-lying, and sitting positions during smartphone use. Positions can cause discomfort in the upper extremity musculoskeletal system. Thirty healthy young adults were recruited and instructed to type on a smartphone for 5 min in each position and 5 min rest between each position. Electromyography data acquired from the upper extremity muscles were analysed using the amplitude probability distribution function (APDF) method. Wrist and elbow joint angles were assessed using the motion analysis system (MyoMotion). In 50% of APDFs, the flexor carpi ulnaris muscle displayed higher muscle activity in the side-lying position, whereas the abductor pollicis brevis (APB) and extensor carpi ulnaris (ECU) muscles showed higher muscle activity in the sitting position. In 90% of APDF, the upper trapezius, ECU, and APB muscles showed higher muscle activity in the sitting position. Additionally, the side-lying position showed a neutral wrist extension angle of 0° compared to the prone and sitting positions (p < 0.05). Using smartphones in the side-lying position is recommended to reduce overuse of the upper-extremity muscles and poor alignment of the wrists.
Keywords: smartphone; typing; positions; sitting; prone; side-lying; surface electromyography; MyoMotion; amplitude probability distribution function; APDF.
Special Issue on: CNB2019 Biomechanics for Performance and Well-being
Increased bone conducted vibration reduces motion sickness in automated vehicles
by Spencer Salter, Cyriel Diels, Stratis Kanarachos, Doug Thake, Paul Herriotts, Didier A. Depireux
Abstract: Motion sickness is common within many forms of transport; it affects most of the population who experience some symptoms at some time. Automated vehicles (AV) offer productivity benefits but also increased incidence of motion sickness. There are mitigation methods with varying degrees of effectiveness to combating motion sickness. Bone conductive vibration (BCV) applied to the head is a proven motion sickness mitigation. It is not known if the level of vibration is important. Twenty-nine participants were subjected to normal urban driving whilst undertaking a 'gaze down' non-driving related task (NDRT) within an AV cabin whilst wearing the BCV device. High and low vibration settings were randomly chosen as were the seating positions in a between participants design. Twenty-five participants successfully completed the experiment. It was found that when the device is applied to the head, the time to nausea increased by up to a factor of 1.6 when set to high over low settings for highly susceptible participants. BCV did not improve task performance.
Keywords: automated vehicles; bone conducted vibration; motion sickness; mitigation; tinnitus.
Biomechanics performance in 30-s chair stand test in patients with medial knee osteoarthritis
by Vitor Ferreira, Leandro Machado, Adélio Vilaça, Francisco Xará-Leite, Paulo Roriz
Abstract: Knee osteoarthritis (OA) is characterised by weakness and knee joint pain which may affect the performance in some activities of daily life like sit-to-stand. The aim of this study is to evaluate the strategies used by patients with knee OA when performing the 30-second chair stand test (30s-CST), and its association with their well-being. Twenty-one patients with knee OA were recruited. A 3D motion analysis system and two force plates were used to capture the kinematics and kinetics during the 30s-CST. The sit-to-stand and the stand-to-sit phases of the test were analysed independently. Significant differences were found (p < 0.05) between the first three and the last three repetitions in the 30s-CST for knee joint moment and power. No significant differences have been found between the most painful knee and the contralateral knee. The correlations found between the subscales of the knee injury and osteoarthritis outcome score (KOOS) and biomechanical parameters were significant (p < 0.05). Patients with the best score in KOOS subscales also showed better performance in the 30s-CST. Assistive technologies that maximise biomechanical strategies could be a valuable contribution to improve the well-being of these patients.
Keywords: sit-to-stand; power; joint moment; knee; knee injury and osteoarthritis outcome score; KOOS; visual analogue scale; VAS; motion analysis; performance; well-being.
Correlation between ankle stiffness and antagonist co-activation in post-stroke subjects
by Edgar Ribeiro, Augusta Silva, Liliana Pinho, Rubim Santos, Francisco Pinho, Andreia S.P. Sousa
Abstract: Tonus dysfunction has been broadly investigated in post-stroke subjects through the evaluation of muscle resistance against stretching, however, its characterisation in functional context is challenging. This study aims to analyse the correlation between intrinsic stiffness, functional stiffness and antagonist co-activation at the ankle joint of post-stroke subjects. Both lower limbs of eight post-stroke participants were evaluated. Intrinsic stiffness was assessed during passive dorsiflexion by an isokinetic dynamometer, functional stiffness during upright standing on a force platform and antagonist co-activation was obtained in upright standing and postural phases of gait initiation and stand-to-sit through the electromyographic signal of ankle muscles. A significant positive correlation was found between antagonist co-activation of ipsilesional tibialis anterior/soleus pair in upright standing and functional stiffness (r = 0.810; p = 0.015; 1-β; = 0.899). Antagonist co-activation seems to be related to functional stiffness in upright standing, suggesting the relevance of evaluating tonus dysfunction through motor control variables obtained under functional conditions.
Keywords: tonus; postural control; movement; ankle; stiffness; antagonist co-activation; upright standing; gait initiation; stand-to-sit; stroke.