<p>The goal of this thesis has been to study the behaviour of the closed loop driver-vehicle-environment in simulation and to find parameters of the synthetic vehicle model, which minimise certain optimisation criteria. A method of optimising parameters using genetic algorithms has been implemented and has proven to work well. Two different driving strategies have been tried in the optimisation of an ISO lane-change maneouvre. The first approach has simulated a beginner driver and his or her behaviour. The second approach simulates an experienced driver and also the possibility of driver adaption to different vehicle types. The implemented driver model has shown to be sufficient to describe the driver's behaviour during lateral maneouvres. A parameter set which minimises the lateral acceleration response on steering wheel angle has proven to be the optimum. This includes a small steering wheel ratio, and a small but positive under steer gradient. The driver has demonstrated the ability to adapt to different vehicles, and therefore different parameter sets, describing the driver, should be used for different problems.</p>

Experienced and novice simulator pilots are subject to some of the constraints of a real flight (or a full flight simulator) situation in a PC based flight simulation. In this thesis, the effects of expertise, working memory capacity, inhibition and divided attention on situation awareness (SA) in simulated flight task environments are investigated. The cognitive aspects underlying the process of situation awareness are explored by analyzing the compound effects of above listed factors. Online and Offline SA measurements obtained from a simulated flight task are used with flight hours standing for expertise and scores of Automated Operation Span Task, Stroop and Coskun&ouml / z visual attention tasks as measurements for working memory capacity, inhibition and divided attention respectively. Regression analyses reveal that expected relationships of simulator pilots&rsquo / SA with expertise and inhibition capacity are supported. On the other hand, expected relationships of SA with working memory and divided attention capacities are not revealed. This situation probably results from unsystematic differences in simulator pilots&rsquo / practices. In addition to the main experiment, simulator pilots&rsquo / levels of neural activity at their dorsolateral prefrontal cortex are also measured during their behavioral performance. The relationships among neural correlates of mental workload induced by the simulated flight are investigated by the functional near-infrared (fNIR) spectroscopy optical brain imaging technology. Theorized mental workload distinction in the scenario of the simulated flight task is successfully observed in both perceived workload declarations and oxygenation measurements by fNIR.

Ytters är skälen till undersökningarna i denna avhandling ekonomiska. Att flyga moderna krisgsflygplan är dyrt. Kan effektiv träning bedrivas intermittent i stället för kontinuerligt? Kan billigare skolflygplan vara ett komplement till krigsflygplan i systemutbildningen? En studie av intermittent flygning på jaktflygplan gjordes i två etapper, först i simulator - del I i avhandlingen - och sedan i luften - del II i avhandlingen. En del av en attackstudie med kompletteringsflygning i skolflygplan är del III.  Studierna hade en experiment-kontrollgrupps-design. I jaktstudien jämfördes avgångna flygförare med aktiv personal. I attackstudien jämfördes aktiva förare vid en experimentdivision med likaledes aktiva förare vid en kontrolldivision. Prestationsvärdering är av avgörande betydelse i undersökningarna. Parallellt med flygförarnas prestation har även deras arbetsbelastning mätts både i simulator och i luften, liksom deras ansträngning, motivation och sinnesstämning. Prognosen från simulator till luften angående förarnas kapacitet och operativa användbarhet kunde förbättras, när hänsyn togs även till andra variabler än prestation. Modeller av flygförares funktion och prestation under flygning kunde konstrueras med utgångspunkt från den utmaning, d v s risk och svårighet, som upplevdes före flygning.

The goal of this thesis has been to study the behaviour of the closed loop driver-vehicle-environment in simulation and to find parameters of the synthetic vehicle model, which minimise certain optimisation criteria. A method of optimising parameters using genetic algorithms has been implemented and has proven to work well. Two different driving strategies have been tried in the optimisation of an ISO lane-change maneouvre. The first approach has simulated a beginner driver and his or her behaviour. The second approach simulates an experienced driver and also the possibility of driver adaption to different vehicle types. The implemented driver model has shown to be sufficient to describe the driver's behaviour during lateral maneouvres. A parameter set which minimises the lateral acceleration response on steering wheel angle has proven to be the optimum. This includes a small steering wheel ratio, and a small but positive under steer gradient. The driver has demonstrated the ability to adapt to different vehicles, and therefore different parameter sets, describing the driver, should be used for different problems.

Les variables neurovégétatives permettent d’évaluer l’état fonctionnel de l’individu, et représentent un intérêt pour mieux comprendre le comportement du conducteur, facteur déterminant de la sécurité routière. Ce travail est centré sur l’évaluation de la charge mentale du conducteur automobile par l’analyse de l’activité électrodermale. L’objectif est d’extraire les meilleurs indicateurs du signal électrodermal pour différencier la charge mentale induite par des situations de conduite réelle. L’analyse d’une trentaine d’indicateurs phasiques a permis de différencier des situations de conduite nominale, comparables en termes d’exigence comportementale mais différentes au niveau cognitif. Après traitement approprié du signal, en particulier en appliquant des transformations log, l’amplitude des réponses électrodermales est apparue comme un des indices les plus discriminants. Toutefois, les différences de charge mentale induites par les situations de conduite n’ont pas exactement correspondu à celles qui avaient été supposées. Une explication alternative mettant en avant des processus d’anticipation est proposée. Trois indicateurs toniques, dont deux sont nouveaux, ont ensuite été testés dans une expérience de double tâche, où une activité secondaire distractive était effectuée simultanément à la conduite. L’un s’est révélé inadapté au profil des signaux, mais les deux autres ont permis d’établir une hiérarchisation partielle de la surcharge induite. Particulièrement sensible à l’aspect cognitif de la distraction, l’évaluation psychophysiologique de la charge mentale par l’activité électrodermale apparaît complémentaire de l’analyse de la performance de conduite. / As an assessment tool for individual’s functional state, autonomic indices can help improving our knowledge of drivers’ behaviour, which is a central road safety causal factor. This work is focused on driver’s mental workload assessment, relying on electrodermal activity analysis. This is an attempt to highlight the most reliable electrodermal indices with the aim to distinguish accurately mental workload elicited by actual driving situations. The analysis of about thirty phasic indices, led to differentiate nominal driving situations. These were selected on the basis of comparable behavioural requirements, but of differences cognitive processes. After appropriate signal processing, (using log transformations in particular), electrodermal responses amplitude has the most potential to distinguish among experimental conditions. However, some of the differences about mental workload were not exactly those which were previously expected. An alternative interpretation of results highlighting anticipation processes is thus proposed. Tonic variations were then studied in a dual task experiment, including two new indices. The distractive power of several secondary tasks, performed while driving, was to be evaluated using these indices. One of the indices was unrelated to signals’ profile. Conversely, the two others gave a clear distinction of potential distraction elicited selectively by each secondary task. Mental workload was thus showed as being evaluated accurately using electrodermal activity analysis. Using objective physiological data and defining new electrodermal indices brought more reliability in the field of mental workload. Thus, electrodermal activity is a good candidate to complete data usually brought by tests or questionnaires.

Les situations de collaboration à distance dans l’industrie induisent de nouvelles contraintes pour les opérateurs. Dans le contexte de l’utilisation d’environnements virtuels collaboratifs immersifs, nous avons mis en place une série d’études portant sur la compréhension mutuelle, et plus particulièrement au partage d’information de nature spatiale. Les résultats de la première étude ont permis de mettre en évidence l’influence du rôle des participants, guides ou manipulateurs, sur les énoncés spatialisés. Les énoncés étaient centrés préférentiellement sur l’action du manipulateur, suggérant la recherche d’un moindre effort collaboratif. Les résultats de deux études sur la production d’énoncés spatialisés ont permis d’identifier que l’exigence mentale pour la production d’énoncés est modulée notamment par la position de la cible à décrire par rapport au destinataire. En effet, selon la position de la cible, le locuteur doit opérer ou non des transformations mentales coûteuses pour prendre la perspective du destinataire. Cet effort peut être amoindri en présence d’indices visuels distaux. La dernière étude, portant sur la compréhension d’énoncés spatialisés, a permis de mettre en évidence que les énoncés centrés sur le destinataire sont les plus simples à comprendre pour une tâche de nature égocentrée. Certains énoncés exocentrés induisent également une moindre exigence mentale, mais uniquement selon certaines conditions. Les résultats sont discutés selon le principe du moindre effort collaboratif et la théorie des cadres de référence. Ce travail a permis de proposer des pistes de développement pour faciliter la collaboration à distance dans les environnements virtuels. / Remote collaborative situations in industry involve new constraints for workers. In the context of using immersive virtual environments to collaborate, we set up a series of experiments focusing on the mutual comprehension, and more specifically on the process of sharing spatial information. Results of the first experiment showed the influence of one collaborator’s role on spatial statements. Guides and manipulators both used statements preferentially centered on manipulator’s action, which supports the least collaborative effort principle. Results of two experiments about spatial statements production allowed to point out that mental workload is modulated by the target position relative to the addressee. According to the target location, the speaker must operate or not cognitively costly mental transformations to take the addressee perspective. However this workload could be lowered by means of visual cues. The last experiment focused on the understanding of spatial statements. It showed that statements centered on the addressee are the easiest to understand when the task is also centered on the addressee. Some exocentered statements could also induce a lower mental workload but only in some conditions. Results are discussed in relation to the least collaborative effort principle and the spatial frames of reference theory. This work opens new leads to facilitate remote collaboration through virtual environments.

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La validité des simulateurs de conduite est une question essentielle pour étayer et valoriser les travaux visant à mieux comprendre les comportements de conduite. Alors que les dimensions subjective et comportementale de la validité ont été régulièrement étudiées, elles font face à certaines limites. A l’opposé, rares sont les études qui se sont intéressées à la validité psychologique des simulateurs. Cette dimension compare l'implication des mécanismes qui sous-tendent les comportements entre conduite réelle et virtuelle. De plus, très peu d’études ont confronté les différentes dimensions de la validité, alors que cela pourrait contribuer au développement d’une métrologie des environnements virtuels. C’est précisément à ce niveau que se situe ce travail de thèse, au cours duquel des mesures classiques de la validité comportementale (vitesse, contrôle latéral) ont été confrontées à des mesures de la validité psychologique examinée sous l’angle de la charge mentale en prenant notamment comme indicateur les clignements oculaires. L’objectif principal était de déterminer si le niveau de charge mentale diffère entre conduite sur route et conduite sur simulateur dans des cas où les comportements observés ne permettent pas de faire de distinction.Pour répondre à cette question, ce travail de thèse a été organisé autour de trois expériences réalisées sur simulateur de conduite et d’une étude sur route réelle. Les deux premières expériences visaient à mieux cerner l’effet de certains facteurs inhérents à la conduite sur route ouverte (trafic, environnement) sur les comportements de conduite et la charge mentale. La troisième expérience était quant à elle destinée à comparer la charge mentale induite par la conduite réelle et la conduite sur simulateur « bas coût », en confrontant cette mesure de la validité psychologique aux mesures comportementales classiques. Enfin, la quatrième expérience a porté sur les effets du retour d’effort du volant sur cette même charge mentale.Les principaux résultats ont mis en évidence un niveau de charge supérieur en conduite simulée par comparaison à la conduite en situation réelle, alors que certaines mesures comportementales (vitesse) n’étaient pas différentes. Cette charge accrue sur simulateur ne semble cependant pas trouver son origine dans le retour d’effort au volant, les modalités de retour testées n’ayant pas eu d’effet sur les indicateurs de la charge. Au final, ce travail confirme que la prise en compte de la validité psychologique, examinée ici sous l’angle de la charge mentale, présente un intérêt dans une démarche d’évaluation, dans le but de mieux cerner le positionnement des utilisateurs face à un dispositif de réalité virtuelle. Il ouvre ainsi des perspectives pour améliorer la validité des simulateurs de conduite. / The validity of driving simulators is an essential subject to support and highlight the works aiming to understand driving behaviours more thoroughly. While the subjective and behavioural dimensions of that validity have often been studied, they encounter a few limits. On the other hand, studies about simulators’ validity are fairly rare. This dimension compares the implication of mechanisms inherent in behaviours between real and virtual driving. Furthermore, very few studies have considered the various dimensions of validity at once, whereas it could contribute to the development of a metrology for virtual environments. This thesis is precisely about this, with confrontations between classical measurements of behavioural validity (speed, lateral control) and measurements of psychological validity, examined from the viewpoint of mental workload - using indicators such as eye blinking. The main objective was to ascertain whether the mental workload levels vary between road driving and simulated driving when the observed behaviours aren’t relevant to make a clear difference.To answer this question, this thesis has been organised around three experiences carried out on driving simulators and a comparison between actual road driving and low-cost simulated driving. Two of those experiences were conducted to finely analyse the effect of some factors inherent to open road driving (traffic, environment) on driving behaviours and mental workload. The third experience was made to compare the mental workload induced by real driving and low-cost simulator driving, by putting this psychological validity measurement against classical behavioural measurements. Lastly, the fourth experience focused on the effects of the driving wheel’s force-feedback on this same mental workload.The main results revealed a higher workload level on simulated driving than on real driving, while some behavioural measurements (speed) were not different. This increased workload with the simulator does not seem to stem from the wheel’s force-feedback, since the tested feedback methods did not have a repercussion on the workload levels. In the end, this work confirms that taking psychological validity - examined here from a mental workload viewpoint - does have an interest within an evaluation process to analyse in a finer fashion the mental state of users when faced with a virtual reality system. It creates prospects to improve the validity of driving simulators.

<p>The advancement of robotic-assisted surgery (RAS) has revolutionized the field by enabling surgeons to perform intricate procedures with enhanced precision, improved depth perception, and more precise control. Despite these advancements, current RAS systems still rely on teleoperation, where surgeons control the robots remotely. The complexity of the master-slave control mechanism, along with the technical challenges involved, can impose significant mental workloads on surgeons. As excessive mental workload (MWL) can adversely affect performance and increase the likelihood of errors, addressing operator mental overload has become crucial for successful operation in RAS. To tackle this problem, there has been increased interest in developing robots that can provide operators with varying levels of assistance based on their MWL (i.e., adaptive system) during task execution. However, the research in this area is notably limited, primarily due to two key factors: the absence of a real-time MWL assessment framework and the lack of effective intervention strategies to mitigate MWL in RAS.</p> <p>This Ph.D. dissertation aims to fill these gaps by designing the adaptive system in RAS and exploring its impact on surgical task performance. The dissertation comprises three studies. The first study demonstrated the feasibility of the adaptive system in RAS by introducing an MWL-triggered semi-autonomous suction tool as a proof-of-concept. Building upon the insights gained from the first study, the second study focused on enhancing the adaptive system's adaptability to more complex RAS tasks. In particular, the second study proposed a task-independent MWL model that had potential to be applied to various RAS tasks. Additionally, more intelligent interventions were investigated. Furthermore, the third study aimed to investigate the benefits of adaptive system in RAS training by introducing a personalized and adaptive training program based on human MWL profile. The findings of this dissertation revealed evidence supporting the effectiveness of the adaptive system in moderating subjects’ MWL, and its potential in enhancing task performance in RAS. This dissertation highlights the potential of incorporating adaptive systems into future RAS platforms, so that to provide valuable support and assistance to surgeons during critical moments and facilitate surgical training by identifying and addressing the specific needs of surgeons.</p>

付記する学位プログラム名: デザイン学大学院連携プログラム / 京都大学 / 新制・課程博士 / 博士(工学) / 甲第24607号 / 工博第5113号 / 新制||工||1978(附属図書館) / 京都大学大学院工学研究科機械理工学専攻 / (主査)教授 椹木 哲夫, 教授 小森 雅晴, 教授 泉井 一浩 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM