Testing usability and trainability of indirect touch interaction: perspective for the next generation of air traffic control systems

This study aims to determine whether indirect touch device can be used to interact with graphical objects displayed on another screen in an air traffic control (ATC) context. The introduction of such a device likely requires an adaptation of the sensory-motor system. The operator has to simultaneously perform movements on the horizontal plane while assessing them on the vertical plane. Thirty-six right-handed participants performed movement training with either constant or variable practice and with or without visual feedback of the displacement of their actions. Participants then performed a test phase without visual feedback. Performance improved in both practice conditions, but accuracy was higher with visual feedback. During the test phase, movement time was longer for those who had practiced with feedback, suggesting an element of dependency. However, this ‘cost’ of feedback did not extend to movement accuracy. Finally, participants who had received variable training performed better in the test phase, but accuracy was still unsatisfactory. We conclude that continuous visual feedback on the stylus position is necessary if tablets are to be introduced in ATC.     

A 3D analysis of the joint torques developed during driver's ingress–egress motion

Providing an easy ingress–egress (I/E) movement remains a challenge for car designers. I/E has been largely studied in kinematics, but not in dynamics. This study proposes: (1) to evaluate and describe the motor torques developed in the lower limbs and lumbar joints during I/E motions and (2) to analyse the influence of the car geometry and subject anthropometry. An experiment was performed to observe 15 subjects of three anthropometrical groups getting in and out of a car mock-up simulating three different vehicle configurations. Motor torques were extracted using an inverse dynamics analysis. Both ingress and egress motions were primarily characterised by large torques. Overall, the taller a subject and the lower the seat of the vehicle were, the larger the peak torques were. Moreover, peak torques were higher for egress than ingress. These results are discussed in regard to the current knowledge on I/E ergonomics.     

Spring-in behavior of curved composites manufactured by Flexible Injection

This paper investigates the manufacturing distortion of curved composite parts manufactured by a new Liquid Composite Molding (LCM) process called Flexible Injection (FI). This technique uses a deformable tool to speed up the fabrication but may generate manufacturing defects when strongly curved shapes are processed. The goal of the study is to evaluate the impact of such heterogeneities on the dimensional stability of the product. Curved components were first manufactured with varying processing conditions to achieve a wide range of layup quality. The shape stability of the samples was then recorded as a function of temperature to measure the thermoelastic component of distortion and experimental results were compared with predictions made by two modeling techniques. Under certain conditions, manufacturing defects can significantly affect the distortion behavior. This suggests that a robust preforming procedure is of primary importance to produce curved parts by Flexible Injection with a high level of repeatability.     

Cognitive conflict in human-automation interactions: a psychophysiological study

The review of literature in sociology and distributed artificial intelligence reveals that the occurrence of conflict is a remarkable precursor to the disruption of multi-agent systems. The study of this concept could be applied to human factors concerns, as man-system conflict appears to provoke perseveration behavior and to degrade attentional abilities with a trend to excessive focus. Once entangled in such conflicts, the human operator will do anything to succeed in his current goal even if it jeopardizes the mission. In order to confirm these findings, an experimental setup, composed of a real unmanned ground vehicle, a ground station is developed. A scenario involving an authority conflict between the participants and the robot is proposed. Analysis of the effects of the conflict on the participants' cognition and arousal is assessed through heart-rate measurement (reflecting stress level) and eye-tracking techniques (index of attentional focus). Our results clearly show that the occurrence of the conflict leads to perseveration behavior and can induce higher heart rate as well as excessive attentional focus. These results are discussed in terms of task commitment issues and increased arousal. Moreover, our results suggest that individual differences may predict susceptibility to perseveration behavior.     

Fruit load or fruit position alters response to temperature and subsequently cherry tomato quality

Changes in fruit–source ratio during the growth and maturation of cherry tomato fruits were studied in combination with increased fruit temperature. Six treatments were compared: the presence or absence of local heating combined with different fruit origins (7P, fruit from trusses pruned to seven flowers; 14P, proximal fruits; 14D, distal fruits from trusses pruned to 14 flowers). 7P were less sensitive to heating whereas 14P and 14D showed greater reduction in water and dry matter (DM) content. Distal fruits had the lowest structural DM (sDM), which could be due to a lower fruit cell number. Heating further decreased the sDM, so that fruit sink size was the lowest for distal fruits subjected to heating. Under low competition (7P), heating had a beneficial effect on sugar and lycopene content, whereas acids, β‐carotene and vitamin C content were reduced. Under high competition (14P, 14D), heating increased the ratio sDM–DM. This was mainly due to the reduced content of sugars and acids, but also to the reduced accumulation of secondary metabolites such as vitamin C, β‐carotene and lycopene. This study underlines the interactions between fruit temperature and the fruit–source ratio and the consequences for fruit composition and nutritional quality. Copyright © 2005 Society of Chemical Industry     

Mid-infrared spectroscopy as a tool for rapid determination of internal quality parameters in tomato

The objective of this study was to investigate the possibility of predicting the quality parameters of tomato by mid-infrared spectroscopy. For 2 years, tomato samples, representing a large variability in the chemical composition, were scanned using the attenuated total reflectance accessory of a Fourier transform spectrometer in the wavenumber region between 4000 and 400 cm⁻¹_. Calibration models were developed using partial least squares (PLS) regression method and were tested with internal validation sample set in the first year. Different spectral preprocessing techniques were investigated and different spectral regions were selected to optimise the calibration models. In addition, the models obtained in 2007 were used to predict the soluble solids, dry matter and total acidity in tomato harvested in 2008.     

A case of association between hepatocellular carcinoma and porphyria variegata

BACKGROUND: A correlation between acute intermittent porphyria or porphyria cutanea tarda and hepatocellular carcinoma (HCC) has been noted in several studies, but only one case of association between HCC and porphyria variegata has been reported. We therefore report another case of association between HCC and porphyria variegata. METHODS: A 54-year-old nurse with familial porphyria variegata who developed an HCC was studied. The diagnosis of porphyria variegata was made in the course of a familial survey by means of measuring lymphocyte protoporphyrinogen oxidase activity, at a time when the patient had no symptoms. Eighteen years later the patient presented with a firm enlargement of the liver. RESULTS: Histologic examination showed a well-differentiated HCC. The diagnosis was confirmed by positive immunostaining for alpha-foetoprotein antibodies. DISCUSSION: Sixteen months after surgical resection of the HCC the patient was still alive.