Tesi sul tema "Physiological drive"

Dyspnea, the awareness of an increase in breathing discomfort, is commonly experienced during physical activity in healthy individuals and in patients with cardiopulmonary disease. It is well established that the intensity of perceived dyspnea is consistently higher during exercise in healthy women compared to men, regardless of age, height, and weight. However, the mechanism(s) of this sex-related difference in activity-related dyspnea is/are poorly understood and represented the primary focus of this thesis.Compared to men, women have smaller lungs, narrower airways, and weaker breathing muscles. These anatomical differences manifest as greater mechanical constraints on ventilation, particularly during the stress of exercise when ventilatory requirements are high. In addition, the amount of work the breathing muscles must perform in order to move a given volume of air into and out of the lungs during exercise is considerably higher in women than men. It is reasonable to predict that, because of these differences, the central nervous system must activate the respiratory muscles (particularly the diaphragm) to a greater extent during exercise in women compared to men to achieve the same level of ventilation and that this higher respiratory muscle activation may account for the increased perception of activity-related dyspnea in women. While it is not feasible to directly measure the neural output of the brains' respiratory control center at rest or during exercise in humans, central neural respiratory motor drive can be assessed indirectly by quantifying the electromyogram of the crural diaphragm (EMGdi) using a special electrode catheter positioned in an individual's esophagus. To date, no previous study, in health or disease, has examined whether the combination of relatively greater dynamic mechanical ventilatory constraints and a higher EMGdi (i.e., neuromechanical uncoupling of the respiratory system) during exercise in women is responsible, at least in part, for sex differences in activity-related dyspnea. To address this important question we compared detailed assessments of EMGdi, respiratory muscle function, ventilation, breathing pattern, operating lung volumes, cardio-metabolic function, and dyspnea intensity and unpleasantness ratings during symptom-limited incremental bicycle exercise testing in 25 healthy, young (20-40 yrs) women and 25 age-matched men. Our results demonstrated relatively greater mechanical constraints on tidal volume expansion at any given ventilation during exercise in women compared to men. The present study was the first to demonstrate that esophageal electrode catheter-derived measures of EMGdi were consistently higher at any given ventilation during exercise in women compared with men and that these differences reflected, in large part, the presence of relatively greater dynamic mechanical ventilatory constraints in women. In keeping with the results of previous studies, sensory intensity and unpleasantness ratings of dyspnea were higher at any given ventilation during submaximal exercise in women compared to men. However, in contrast to our a priori hypothesis, these perceptual differences could not be readily explained by greater neuromechanical uncoupling of the respiratory system, but primarily reflected the awareness of a relatively higher EMGdi (or central neural respiratory motor drive) needed to achieve any given ventilation during exercise in the setting of greater dynamic mechanical ventilatory constraints in women. These findings may have implications for our understanding of the physiological mechanisms of sex differences in activity-related dyspnea in variants of health (e.g., aging) and in patients with cardiopulmonary disease.
La dyspnée, définie comme la conscience d'une augmentation de gêne respiratoire, est souvent connu pendant l'activité physique chez les sujets sains ainsi que chez les patients ayant une maladie cardio-pulmonaire. Il est bien établi que l'intensité de la dyspnée perçue est systématiquement plus élevée au cours de l'exercice chez les femmes en bonne santé par rapport aux hommes, indépendamment de l'âge, de la taille et du poids. Cependant le/les mécanisme(s) de cette différence sont mal compris et la clarification de ceux-ci comportent l'objet principal de la thèse en question.Comparativement aux hommes, les femmes ont de plus petits poumons, des voies respiratoires plus étroites et des muscles respiratoires plus faibles. Ces différences anatomiques se manifestent par de plus grandes contraintes mécaniques sur la ventilation, en particulier pendant le stress de l'exercice lorsque les besoins ventilatoires sont élevés. Par conséquent, le travail que les muscles respiratoires doivent effectuer afin de déplacer un volume défini d'air dans les poumons pendant l'exercice est considérablement plus élevé chez les femmes que chez les hommes. En raison de ces différences, nous prévoyons que le système nerveux central doit activer les muscles respiratoires (notamment le diaphragme) dans une plus grande mesure chez les femmes pour atteindre le même niveau de ventilation et que cette activation supérieure peut expliquer la perception accrue de la dyspnée liée à l'activité chez les femmes. Même s'il n'est pas possible de mesurer directement les signaux envoyés par le centre de contrôle respiratoire chez l'homme, le contrôle moteur de la respiration peut être évalué indirectement en quantifiant l'électromyogramme du diaphragme crural (EMGdi) en utilisant un cathéter à électrode spécialisée placée dans l'oesophage d'un individu. À ce jour, aucune étude n'a examiné si la combinaison de contraintes ventilatoires mécaniques plus grandes et d'un EMGdi plus élevé pendant l'exercice chez les femmes est responsable des différences de sexe dans la dyspnée liée à l'activité. Nous avons donc comparé des évaluations détaillées de EMGdi, de fonction musculaire respiratoire, de ventilation, de modèle de respiration, de volumes pulmonaires opérationnels, de fonction cardio-métabolique, et d'intensité de la dyspnée et des cotes de désagréments lors de tests d'exercice incrémental de vélo dans 25 jeunes (20-40 yrs) femmes saines et 25 hommes sains du même âge. Nos résultats démontrent des contraintes mécaniques sur l'expansion du volume courant pendant l'exercice plus fortes chez les femmes par rapport aux hommes. La présente étude est la première à démontrer que les mesures de cathéter à électrodes œsophagiennes dérivés de EMGdi étaient systématiquement plus élevés peu importe le niveau de ventilation au cours de l'exercice chez les femmes par rapport aux hommes et que ces différences reflètent, en grande partie, la présence de contraintes ventilatoires mécaniques dynamiques relativement plus grande chez les femmes. En accord avec les résultats d'études antérieures, l'intensité sensorielle et le désagrément de dyspnée ont été supérieurs à n'importe quelle ventilation donnée au cours de l'exercice sous-maximal chez les femmes par rapport aux hommes. Cependant, contrairement à notre hypothèse a priori, ces différences de perception ne peuvent être facilement expliquées par un plus grand découplage neuromécanique du système respiratoire et reflètent la conscience d'une EMGdi relativement élevée (ou moteur d'entraînement respiratoire neural central) nécessaire pour atteindre une ventilation donnée pendant l'exercice dans le cadre de contraintes ventilatoires mécaniques dynamiques plus grande chez les femmes. Ces résultats pourraient avoir des implications dans notre compréhension des mécanismes de différences de sexe dans la dyspnée liée à l'activité dans les variantes de la santé et chez les patients ayant une maladie cardio-pulmonaire.

Background: Acute and chronic respiratory failure occurs as a consequence of an imbalance in the load-capacity-drive relationship of the respiratory system. Despite the high morbidity and mortality of these patients, clear clinical strategies for assessment and subsequent management have been lacking due to the limited high quality data available. The aim of this thesis was to evaluate novel techniques to monitor patients with acute respiratory deterioration as well as the use of specific monitoring and non-invasive ventilation strategies in patients with chronic respiratory failure, which could translate into important clinical benefits. Methods: Three clinical physiological studies were performed. Firstly, a randomised controlled trial evaluated an automated novel hybrid pressure-volume mode of non-invasive ventilation to treat obesity hypoventilation syndrome. Although the primary outcome measure was gas exchange at three months, important physiological measures including physical activity, sleep quality and their relationship to weight loss were also investigated. Secondly, an observational cohort trial investigated the role of a novel advanced physiological biomarker, neural respiratory drive, to identify treatment failure and readmission risk in patients admitted to hospital with an acute exacerbation of chronic obstructive pulmonary disease. The third physiological trial investigated, in patients with persistent hypercapnic respiratory failure following an acute exacerbation of COPD as part of a large randomised controlled trial, the efficacy and mechanism of action of home mechanical ventilation and its effect on sleep quality compared with standard oxygen therapy. Results: The automated volume targeted mode of ventilation demonstrated no advantage in physiological and clinical outcomes above a nurse-led protocolised standard set up of non-invasive ventilation in the management of obesity hypoventilation syndrome. The trial was the first to demonstrate that the management of sleep disordered breathing and chronic respiratory failure in obesity hypoventilation syndrome confers an improvement in objectively assessed physical activity as well as weight loss, which has important clinical implications. In the second trial, neural respiratory drive was validated as a novel physiological biomarker to monitor acute clinical change during hospital treated exacerbations of COPD. Furthermore, patients in whom neural respiratory drive failed to fall in response to treatment prior to hospital discharge had a significantly higher risk of hospital readmission within 14 days, again, highlighting the important clinical implications of detailed physiological observations. The third physiological trial confirmed previous data indicating that an important mechanism of action of home mechanical ventilation in COPD is through improvements in central respiratory drive, but this conclusion was given greater confidence by the use of advanced physiological monitoring. Conclusion: The data presented in this thesis provide clinically important information on the physiological targeting of set-up of non-invasive ventilation in patients with chronic respiratory failure secondary to obesity hypoventilation syndrome and severe COPD. Important markers of treatment success in the management of chronic respiratory failure in obesity hypoventilation syndrome have been identified including physical activity, sleep quality and weight loss. These data have also established the potential clinical role of advanced physiological biomarkers of neural respiratory drive to monitor clinical change and to risk stratify patients during acute exacerbations of COPD. Finally, the data in this thesis provides further evidence that the major mechanism of action of home mechanical ventilation in hypercapnic COPD patients is the modification of central respiratory drive.

Background & rationale. "Dyspnea" refers to the awareness of breathing discomfort that accompanies an increase in physical activity in health and across various diseases. It is arguably the most severe and burdensome symptom experienced by patients with chronic pulmonary disorders and is an important contributor to physical activity-limitation and adverse health outcomes, including hospitalization and death. Nevertheless, the mechanisms of dyspnea on exertion in health and disease remain partially understood. Accumulating evidence implicates neuromechanical uncoupling of the respiratory system as a likely mechanism of activity-related dyspnea, particularly in patients with chronic pulmonary diseases. According to this hypothesis, sensory intensity and unpleasantness ratings of dyspnea increase as a function of the widening disparity (as exercise progresses) between neural respiratory drive and the simultaneous response of the respiratory system, particularly as it relates to tidal volume (VT) expansion. An alternative and largely untested hypothesis states that the increased perception of dyspnea during exercise may reflect the awareness of increased neural respiratory drive needed achieve any given ventilation (V· E) in the presence of "abnormal" restrictive constraints on VT expansion. To date, the contribution of pathophysiological abnormalities in neural respiratory drive, dynamic respiratory mechanics and their interaction to the symptom of dyspnea during exercise in patients with chronic pulmonary disorders has proved difficult to study (beyond correlation) due to the presence of multiple co-morbidities that may independently contribute to the perception of dyspnea. Research Objectives. In light of the information cited above, the objectives of this research project were to better understand the physiological mechanisms of exertional dyspnea. Methods. This randomized cross-over study examined the acute effects of external thoracic restriction by chest wall strapping (CWS) – an accepted model of the "abnormal" restrictive constraints on VT expansion typical of patients with chronic pulmonary disorders - on detailed assessments of V· E, breathing pattern, dynamic respiratory mechanics, neural respiratory drive (as assessed by changes in the diaphragm electromyogram; EMGdi), and sensory intensity and unpleasantness ratings of dyspnea during symptom-limited incremental cycle exercise testing in 20 healthy, young men with normal lung function and cardiorespiratory fitness. Results. The key findings of this study include: [1] relatively greater dynamic mechanical constraints on VT expansion were evident during exercise with vs. without CWS; [2] EMGdi was consistently higher during exercise with vs. without CWS; [3] CWS had no effect on neuromechanical coupling of the respiratory system, as evidenced by relative preservation of the relationship between increasing EMGdi and VT expansion (adjusted for CWS-induced reductions in vital capacity) during exercise; [4] sensory intensity and unpleasantness ratings of dyspnea were significantly higher during exercise with vs. without CWS; and [5] CWS had no effect on the relationship between increasing EMGdi and each of the intensity and unpleasantness of dyspnea during progressive exercise. Conclusions & implications. We concluded that the increased perception of dyspnea during exercise with CWS could not be readily explained by increased neuromechanical uncoupling of the respiratory system, but that it likely reflected the awareness of increased neural respiratory drive needed to overcome the "abnormal" restrictive constraints on VT expansion. These findings may have implications for our understanding of the pathophysiological mechanisms of exertional dyspnea causation in patients with chronic restrictive lung disorders. This information, in turn, may aid in the development of more effective dyspnea relieving interventions for use in these patients.
Contexte et raisonnement. La «dyspnée» désigne une prise de conscience de gêne respiratoire se manifestant généralement à l'effort autant chez ceux en santé que ceux atteints de diverses maladies. Sans doute, il est symptôme le plus lourdement ressenti par patients atteints de maladies pulmonaires chroniques (MPC) pour son effet limitant sur l'activité physique et effet nocif sur la santé, y compris l'hospitalisation et la mort. Néanmoins, les mécanismes de la dyspnée d'effort en temps de santé et maladie restent que partiellement comprises. Des étudies ultérieurs suggèrent le découplage neuromécanique du système respiratoire comme mécanisme de dyspnée d'effort, en particulier chez patients atteints de MPC. Selon cette hypothèse, l'intensité sensorielle et le sentiment de malaise augmentent en fonction d'une disparité croissante entre pulsion respiratoire neuronale et réaction simultanée du système respiratoire, concernant notamment le volume courant (VT) d'extension. Une hypothèse alternative et largement non vérifiée suggère qu'une perception de la dyspnée élevée durant exercice reflète une prise de conscience d'une pulsion respiratoire neuronale nécessaire pour atteindre une ventilation (V· E) donnée lors de contraintes "anormales" sur l'expansion VT. À ce jour, la contribution des anomalies physiopathologiques sur la pulsion respiratoire neural, mécanique respiratoire dynamique et symptôme de la dyspnée au cours de l'exercice chez patients atteints de MPC s'est révélée difficile à étudier (au-delà de corrélation) en raison de présence de multiples comorbidités contribuant indépendamment à la perception de la dyspnée. Objectif. En guise de l'information présentée précédemment, nous tentons de mieux comprendre les mécanismes physiologiques de dyspnée d'effort. Méthode. Cette étude randomisée, contrôlée et croisée a permis d'examiner les effets aigus de la restriction thoracique externe par le cerclage de paroi thoracique (chest wall strapping, CWS),- un modèle accepté qui assimile les contraintes restrictives "anormales" sur l'expansion du VT de patients avec troubles pulmonaires chroniques - sur la V· E, mode de respiration, mécanique respiratoire dynamique, pulsion respiratoire neural (évaluée par changements dans l'électromyogramme du diaphragme; EMGdi), cotes d'intensité sensorielle et malaise accompagnant la dyspnée au cours d'épreuve incrémental d'effort limitée par symptômes, dans 20 jeunes hommes en santé et à fonctions pulmonaire et cardiorespiratoire normaux. Résultats. Les résultats principaux furent : [1] Les contraintes mécaniques dynamiques sur l'expansion du VT étaient relativement plus grandes durant effort avec CWS que sans; [2] L'EMGdi était systématiquement plus élevé lors de l'effort avec CWS que sans; [3] Le CWS n'avait aucun effet sur le découplage neuromécanique du système respiratoire, comme la relation entre EMGdi et expansion du VT (normalisée selon la réduction de la capacité vitale causée par le CWS) durant effort a été maintenue. [4] L'intensité sensorielle et le sentiment de malaise accompagnant la dyspnée étaient sensiblement plus élevés durant effort avec CWS que sans; et [5] Le CWS n'a eut aucun effet sur la relation entre une l'EMGdi augmentée, et l'intensité sensorielle et malaise ressentie, pris séparément durant l'effort progressif. Conclusions. Nous concluons que la perception accrue de la dyspnée durant effort avec CWS n'est pas aisément expliquée par découplage neuromécanique du système respiratoire élevé, mais qu'elle reflète plutôt la prise de conscience de la pulsion respiratoire neural supplémentaire nécessaire pour surmonter les contraintes restrictives « anormales » sur l'expansion du VT. Nos résultants permettent d'approfondir notre compréhension des mécanismes physiopathologiques causant la dyspnée d'effort chez patients à troubles pulmonaires chroniques, et s'avère important pour le développement de modalités soulageant la dyspnée chez ces patients dans le futur.

Vehicle safety and road safety are two important issues. They are related to each other and road accidents are mostly caused by driver distraction. Issues related to driver distraction like eating, drinking, talking to a passenger, using IVIS (In-Vehicle Information System) and thinking something unrelated to driving are some of the main reasons for road accidents. Driver distraction can be categorized into 3 different types: visual distraction, manual distraction and cognitive distraction. Visual distraction is when driver's eyes are off the road and manual distraction is when the driver takes one or both hands off the steering wheel and places the hand/s on something that is not related to the driving safety. Cognitive distraction whereas happens when a driver's mind is not on the road. It has been found that cognitive distraction is the most dangerous among the three because the thinking process can induce a driver to view and/or handle something unrelated to the safety information while driving a vehicle. This study proposes a physiological measurement to detect driver cognitive distraction. Features like lips, eyebrows, mouth movement, eye movement, gaze rotation, head rotation and blinking frequency are used for the purpose. Three different sets of experiments were conducted. The first experiment was conducted in a lab with faceLAB cameras and served as a pilot study to determine the correlation between mouth movement and eye movement during cognitive distraction. The second experiment was conducted in a real traffic environment using faceAPI cameras to detect movement on lips and eyebrows. The third experiment was also conducted in a real traffic environment. However, both faceLAB and faceAPI toolkits were combined to capture more features. A reliable and stable classification algorithm called Dynamic Bayesian Network (DBN) was used as the main algorithm for analysis. A few more others algorithms like Support Vector Machine (SVM), Logistic Regression (LR), AdaBoost and Static Bayesian Network (SBN) were also used for comparison. Results showed that DBN is the best algorithm for driver cognitive distraction detection. Finally a comparison was also made to evaluate results from this study and those by other researchers. Experimental results showed that lips and eyebrows used in this study are strongly correlated and have a significant role in improving cognitive distraction detection.

Driving a vehicle involves a series of events, which are related to and evolve with the mental state (such as sleepiness, mental load, and stress) of the driv- er. These states are also identified as causal factors of critical situations that can lead to road accidents and vehicle crashes. These driver impairments need to be detected and predicted in order to reduce critical situations and road accidents. In the past years, physiological signals have become conven- tional measures in driver impairment research. Physiological signals have been applied in various studies to identify different levels of mental load, sleepiness, and stress during driving. This licentiate thesis work has investigated several artificial intelligence algorithms for developing an intelligent system to monitor driver mental state using physiological signals. The research aims to measure sleepiness and mental load using Electroencephalography (EEG). EEG signals, if pro- cessed correctly and efficiently, have potential to facilitate advanced moni- toring of sleepiness, mental load, fatigue, stress etc. However, EEG signals can be contaminated with unwanted signals, i.e., artifacts. These artifacts can lead to serious misinterpretation. Therefore, this work investigates EEG arti- fact handling methods and propose an automated approach for EEG artifact handling. Furthermore, this research has also investigated how several other physiological parameters (Heart Rate (HR) and Heart Rate Variability (HRV) from the Electrocardiogram (ECG), Respiration Rate, Finger Tem- perature (FT), and Skin Conductance (SC)) to quantify drivers’ stress. Dif- ferent signal processing methods have been investigated to extract features from these physiological signals. These features have been extracted in the time domain, in the frequency domain as well as in the joint time-frequency domain using wavelet analysis. Furthermore, data level signal fusion has been proposed using Multivariate Multiscale Entropy (MMSE) analysis by combining five physiological sensor signals. Primarily Case-Based Reason- ing (CBR) has been applied for drivers’ mental state classification, but other Artificial intelligence (AI) techniques such as Fuzzy Logic, Support Vector Machine (SVM) and Artificial Neural Network (ANN) have been investigat- ed as well. For drivers’ stress classification, using the CBR and MMSE approach, the system has achieved 83.33% classification accuracy compared to a human expert. Moreover, three classification algorithms i.e., CBR, an ANN, and a SVM were compared to classify drivers’ stress. The results show that CBR has achieved 80% and 86% accuracy to classify stress using finger tempera- ture and heart rate variability respectively, while ANN and SVM reached an accuracy of less than 80%.
Vehicle Driver Monitoring

Despite of the documented impacts of the so-called green revolution, food security in the world faces new challenges in terms of population growth, increases in no-agricultural land use (urbanization), and climate change. Trends in food security show that the world community is operating within two limits of food system: (i) the quantity of food that can be produced under a given climate; and (ii) the quantity of food needed by a growing and changing population. Therefore, taking food security successfully into the future requires novel approaches to boost agricultural productivity in order to balance food supply and demand without expanding the agricultural land. To date, progress in wheat yield has been largely the result of the development of dwarf varieties through introgression of reduced height (Rht) genes. The height reductions arising from the presence of these genes increased yield by alteration of partitioning of dry matter and nitrogen in favour of the spike. However, increased partitioning through additional reductions in plant height is not likely; as comparative studies indicate that wheat yield is reduced when plants are shortened beyond a threshold, and most of the modern cultivars have reached the optimal height. Therefore, this dissertation aimed to identify the physiological attributes able to produce yield increases in the Rht genotypes with the optimal heights. Approaches based on physiological understanding of yield are necessary for developing genotypes combining high yielding potential and agronomic traits of superior adaptation, and for understanding yield limiting factors. Yet, direct measurement of physiological variables is often difficult or expensive; as an example, measuring plant water status in the field is problematic, with techniques such as psychrometry generally only being suitable for laboratory studies. Therefore, proxy such as tissue RWC may be a good alternative measure of plant water status. We aimed to address these questions with three components of experimental research :(i) proxy-based screening to increased photosynthetic rate and water use efficiency in wheat; (ii) determinants of increased HI in lines with different Rht genes (b, c) when incorporated into contrasting background wheat genomes (B, D), and the relative effect on N partitioning during grain filling; (iii) analyses of stable isotopes (δ²H, δ¹⁸O, δ¹⁵N and δ¹³C) in an agronomic perspective in alley cropping systems associated with adjacent N₂ fixing trees, in terms of hydraulic redistribution, N availability and crop yields. In this thesis, the proxy-based approach to crop selection was defined as a surrogate-based (proxy and surrogate used interchangeably) screening of cultivars for morphological, anatomical, and physiological traits of performance or crop environmental responses. The research proposed steps for conducting a proxy-based crop selection programme. A comparative screening of 23 Eps cultivars and ranking for traits of photosynthetic and water use efficiency showed the correlative relationships of SLA to An, WUEi, leaf N, Δ¹³C, Kh, leaf RWC, and IVD. Additionally, it was observed that IVD may influence WUE and Amax. It was suggested that these relationships of SLA to traits of photosynthesis possibly resulted from the association of SLA and the leaf biochemical characteristics. Attention was also given to examining the mechanistic foundations that determine the relationship between plant height and yield. The results showed the straw-shortening significantly correlated both with Amax and Kh; and SLA decreased with the level of dwarfing; and the Amax related both Kh and SLA. Therefore, it was proposed that the straw-shortening may affects Amax by exerting a controlling influence over Kh through SLA. Moreover, both the partitioning of N to spike and the flag leaf N were related to plant height and growth stage. Additionally, the increased post-anthesis partitioning of N to grain associated with high N uptake rate and high MRT of N were probably the traits behind increased NUE and NHI. The data also indicated that increased grain number per spike, kernel weight and reduced peduncle length might be the driver of the increased HI in this experiment. The test of the hypothesis that there might be practical application of the analyses of the natural abundance of stable isotopes (δ²H, δ¹⁸O, δ¹³C, and δ¹⁵N) and isotopic mixing model by IsoSource to understand plant interactions in terms of water redistribution and nitrogen transfer and uptake in agroforestry systems, indicated a consistent gradient in depletion of wheat xylem water δ²H, δ¹⁸O, and δ¹⁵N in leaf as moving further away from the tree line. The data also reflected a consistent pattern of isotopic values (δ²H, δ¹⁸O, and δ¹⁵N) in wheat in the proximity of the tree being similar to that of the tree, suggesting they were using the same source of water and N. Similarly, an isotopic mixing model data showed that the crops in the proximity of the trees accessed considerably amounts of the water and nitrogen redistributed by trees. The study also indicated the improvement in water use efficiency, chlorophyll content, grain number per spike, and grain yield for the crops nearest to the trees for a distance up to 5 m. In conclusion, selection for increased HI should shift focus from reduced plant height to include increased grain number and kernel weight, increased partitioning of N to spike, reduced peduncle length, and low SLA. Finally, the hypothesis that efflux of water and N in agroforestry system from tree roots in topsoil and influences a number of physiological functions of neighbouring crops was confirmed by isotopic and physiological data.

Les centres respiratoires du tronc cérébral régulent la ventilation. Les signaux qu’ils émettent sont transmis aux muscles inspiratoires. La commande respiratoire peut être monitorée au lit du patient au moyen de l’activité électrique diaphragmatique (Eadi) ou de la pression d’occlusion à 100 ms (P0.1). Le monitorage de ces paramètres devrait permettre d’optimiser l’assistance ventilatoire délivrée.Il n’existe que peu de données relatives aux valeurs normales d’Eadi et de P0.1 et à leurs variations en situations non physiologiques. La question de la fiabilité des mesures réalisables au lit du patient reste également débattue. Ce projet de thèse visait à augmenter les connaissances relatives à l’Eadi et à la P0.1.Les travaux réalisés ont permis de : 1. mieux caractériser l’amplitude de l’Eadi en situations physiologique et non physiologiques, 2. démontrer que la valeur maximale d’Eadi reflète bien l’intensité de la commande, 3. démontrer que le monitorage de l’Eadi est complémentaire à celui du profil ventilatoire et de l’effort inspiratoire, 4. démontrer que Eadi et P0.1 sont bien corrélés,5. démontrer que l’Eadi peut être utilisé pour optimiser les réglages en aide inspiratoire et que ceci améliore la synchronisation patient-ventilateur, 6. démontrer que les variations de P0.1 sont bien reflétées par les mesures de P0.1 réalisées par les ventilateurs et 7. démontrer que les ventilateurs sous-estiment les P0.1 de référence. Des études complémentaires sur de plus grands collectifs et portant sur le devenir des patients doivent être réalisées avant que le monitorage de l’Eadi et de la P0.1 puissent être recommandés comme techniques de routine chez les patients ventilés
The brainstem respiratory centers are in charge of breathing regulation. Their output is transmitted to the inspiratory muscles. Respiratory drive monitoring can be performed using the electrical activity of the diaphragm (Eadi) or the measurement of the occlusion pressure at 100 ms (P0.1). Monitoring these parameters should allow improving the delivered ventilator assist. Few data regarding the normal values of Eadi and P0.1 and their variations in non-physiological situations are available. The question of the reliability of the bedside measurements also remains opened.This thesis project aimed at increasing our knowledge on Eadi and P0.1 measurements. The studies performed allowed 1. better characterizing Eadi and P0.1 normal values in physiological and non-physiological situations. 2. demonstrating that Eadi maximal value well reflects inspiratory drive intensity, 3. demonstrating that Eadi monitoring provides additional information compared to respiratory profile and inspiratory effort monitoring, 4. demonstrating that Eadi and P0.1 are well correlated, 5. demonstrating that Eadi can be used to improve the ventilator settings during pressure support and that this strategy allows improving patient-ventilator synchrony. 6. showing that the P0.1 variations are well reflected by the P0.1 measured by the ventilators, 7. demonstrating that overall the P0.1 measured by the ventilators underestimate the reference P0.1. Additional studies in more patients and studies designed to assess the impact on patient’s outcome of using Eadi and P0.1 monitoring should be perform before recommaending these monitorings as a standard procedure in ventilated patients

Two previous studies performed at Virginia Tech have shown that it is feasible to detect drowsy drivers using driving performance and physiological measures. Therefore, assuming that drowsiness can be detected, it becomes important to develop methods (countermeasures) by which drivers can regain and maintain alertness. The current study was thus undertaken in an attempt to evaluate three subsidiary tasks which differed only in regard to input modality (auditory, tactual, or visual) in terms of: 1) the degree to which they aided the driver by maintaining or restoring alertness; and 2) the degree to which the responses to these tasks could be used to detect drowsiness. Subjective measures of drowsiness were also obtained to provide an additional source of verification of level of drowsiness. To accomplish these objectives, a total of 12 male and female driver-subjects drove a moving-base simulator continuously from 12:30 a.m. to 3:00 a.m. During this time, the subjects performed each of the subsidiary tasks for a 30-minute period; they also drove for a 30-minute period during which no subsidiary task was performed. During the simulated, nighttime, highway driving scenario, 20 driving performance, behavioral, and physiological measures were collected for each 3-minute driving interval, along with 5 subsidiary task measures and subjective alertness ratings. The experimental results indicated that none of the three subsidiary tasks provided an effective means of maintaining driver alertness. However, the results of a second series of discriminant analyses did indicate that driver impairment due to drowsiness could be reliably detected with linear combinations of subsidiary task and driving measures. In fact, promising discriminant models for the auditory and visual tasks were identified which employed a subsidiary task response measure of the number of correct responses to the subsidiary task during each 6-minute driving interval as well as a physiological measure of the subject's heart rate variance; these models showed overall classification error percentages as low as 3% and 8%. Finally, the analyses of the subjective alertness ratings indicated that subjects' ratings were not significantly affected by either the type of subsidiary task performed or time-on-task.
Ph. D.

Few attempts have been made to use physical and physiological driver characteristics to predict driver drowsiness. As a result, a reliable drowsy driver detection system has yet to be devised. Thus, the primary objectives of this research were to determine whether driving characteristics and response variables could be used to detect eyelid closure associated with edrowsiness, and. to provide ‘potential measures of driver· drowsiness. In. the study, eyelid closure was defined as the measurement standard of drowsiness. Eyelid closure, in studies conducted at Duke University, was a reliable measure of drowsiness. A computer simulated nighttime driving task introduced 90 minutes of typical highway driving to twenty driver/subjects seated ixx a moving-base driving simulator. Each driver/subject drove under two conditions--rested and after 19 hours of being awake. During the 90 minutes of driving, two types of low—level stimuli, steering wheel torque and front wheel displacement, were applied to the simulation. Responses to these stimuli as well as driving I measures from the intervals between stimuli were analyzed for variations associated with eyelid closure. Seventeen dependent variables were investigated.
Ph. D.
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Falling asleep while operating a moving vehicle is a contributing factor to the statistics of road related accidents. It has been estimated that 20% of all accidents where a vehicle has been involved are due to sleepiness behind the wheel. To prevent accidents and to save lives are of uttermost importance. In this thesis, given the world’s largest dataset of driver participants, two methods of evaluating driver sleepiness have been evaluated. The first method was based on the creation of epochs from lane departures and KSS, whilst the second method was based solely on the creation of epochs based on KSS. From the epochs, a number of features were extracted from both physiological signals and the car’s controller area network. The most important features were selected via a feature selection step, using sequential forward floating selection. The selected features were trained and evaluated on linear SVM, Gaussian SVM, KNN, random forest and adaboost. The random forest classifier was chosen in all cases when classifying previously unseen data.The results shows that method 1 was prone to overfit. Method 2 proved to be considerably better, and did not suffer from overfitting. The test results regarding method 2 were as follows; sensitivity = 80.3%, specificity = 96.3% and accuracy = 93.5%.The most prominent features overall were found in the EEG and EOG domain together with the sleep/wake predictor feature. However indications have been made that complexities might contribute to the detection of sleepiness as well, especially the Higuchi’s fractal dimension.

In competitive golf, the player’s ability to hit the ball a long distance affects the score in a positive way. Swing kinematics is considered an important factor in driver performance; one way of improving swing kinematics is through strength and power training. Subsequently, high-level golfers and their coaches often explore novel ways of increasing the distance of a shot, in particular driver carry distance (CD). This licentiate thesis presents two studies with the overall aim of studying how swing kinematic and physical characteristics are associated with driver performance among intercollegiate golf players. The studies report swing kinematics associated with driver performance (study 1) and the impact of isokinetic rotational training on driver performance and swing kinematic variables (study 2). The methods used were (1) a cross-sectional correlation study (n=15) and (2) an open trial intervention study (n=20). The studies investigated (1) the relationship between golf swing kinematics and driver performance, and (2) the impact of strength training on swing kinematics and driver performance variable. The results show variables that were distinctive for the club head speed (CHS) were mainly during the downswing: greater X-factor stretch; and higher pelvis peak speed. Whilst, factors distinctive to the regression model for CD were mainly at impact: reduced thorax rotation; and greater thorax lateral bend. Nine weeks of isokinetic training increased seated rotational force and power, peak arm speed and arm acceleration, ball speed, and CD more compared to isotonic training. Even though isokinetic training did not increase CHS, it did result in greater CD. This licentiate thesis contributes to the understanding of which variables influence driver performance, in particular CD, among high-level golfers. Segmental interactions (pelvis-thorax), lead arm speed and acceleration, isokinetic and isotonic training. These results may guide training interventions aiming to improve driver and golf performance among high-level golfers, particularly those with a background of strength training. Future studies could investigate how the interaction between swing kinematics, clubhead trajectory, and driver performance variables differ between male and female golfers.

Successful driver performance is fundamental in preventing vehicle crashes. Stress can negatively affect driver performance and significantly increase the risk of a crash. Therefore, an in-vehicle warning system for driver stress levels is needed to continuously predict dangerous driving situations and proactively alert drivers to ensure safe and comfortable driving. As a result of the recent developments in sensing technologies and context recognition, driver stress can be detected using multimodal measurements. This thesis proposes a general framework for building a driver stress level detection system based on multimodal measurements and adopts different approaches to maximise the performance of the system.

This research program examined the factors of motivation and genetic variations for their effects on sleepiness and performance. The results suggest that certain genetic variations were found to influence aspects of physiological and subjective sleepiness as well as performance outcomes. Motivation had no effect on performance when partially sleep deprived, but motivation improved task performance on a low-order cognitive task when fully rested. The results suggest sleepiness is resistant to motivation to improve performance. As such, drivers who continue to drive while sleepy by applying extra effort to the task of driving are engaging in a risky driving behaviour.

The incidence of sleep-related crashes has been estimated to account for approximately 20% of all fatal and severe crashes. The use of sleepiness countermeasures by drivers is an important component to reduce the incidence rates of sleep-related crashes. Taking a brief nap and stopping for a rest break are two highly publicised countermeasures for driver sleepiness and are also believed by drivers to be the most effective countermeasures. Despite this belief, there is scarce evidence to support the utility of these countermeasures for reducing driver sleepiness levels. Therefore, determining the effectiveness of these countermeasures is an important road safety concern. The current study utilised a young adult sample (N = 20) to investigate the effectiveness of a nap and an active rest break. The countermeasures effects were evaluated by physiological, behavioural (hazard perception skill), and subjective measures previously found sensitive to sleepiness. Participants initially completed two hours of a simulated driving task followed by a 15 minute nap opportunity or a 15 minute active rest break that included 10 minutes of brisk walking. After the break, participants completed one final hour of the simulated driving task. A within-subjects design was used so that each participant completed both the nap and the active rest break conditions on separate occasions. The analyses revealed that only the nap break provided any meaningful reduction in physiological sleepiness, reduced subjective sleepiness levels, and maintained hazard perception performance. In contrast, the active rest break had no effect for reducing physiological sleepiness and resulted in a decrement in hazard perception performance (i.e., an increase of reaction time latencies), with a transient reduction in subjective sleepiness levels. A number of theoretical, empirical and practical issues were identified by the current study.

Drowsiness is one of the main contributors to road crashes. This research program examines the utility of drowsiness detection based on singular and hybrid approaches using physiological signals of EEG, EOG, and ECG. Four supervised machine learning models were developed to detect drowsiness levels, using physiological features known to be associated with drowsiness and performance impairment. The ground truth was subjective sleepiness responses while performing a repetitive reaction time task. The outcome of the study indicates that the selected features provided higher performance in the hybrid approaches than the singular approaches, which could be useful for future research implications.

Les systèmes d’efflux tripartite de type Resistance, Nodulation and cell-Division (RND) sont essentiels dans le maintien de phénotypes de résistance multidrogues et contre les métaux lourds dans nombreuses bactéries Gram-négatives. Le transport de ces composés toxiques hors de la cellule est permis par l’assemblage d’une protéine de type antiporteur cation/proton (unité RND) insérée dans la membrane interne, connectée à une protéine insérée dans la membrane externe, pour former un canal de sorti qui traverse l’entièreté de l’enveloppe cellulaire. Le troisième composant du système, la protéine de type membrane fusion protein (MFP) qui est aussi appelée periplasmic adaptor protein (PAP), est requis pour permettre l’assemblage de tout ce complexe à trois composants. Cependant, les MFPs sont supposées jouer un rôle important et actif dans le mécanisme d’efflux du substrat. Pour mieux comprendre le rôle des MFPs au sein des systèmes d’efflux de type RND, nous avons étudié les protéines ZneB (précédemment appelée HmxB) et SilB, les composants périplasmiques des systèmes ZneCBA et SilABC responsables de la résistance aux métaux lourds chez Cupriavidus metallidurans CH34. Nous avons identifié la spécificité de liaison au substrat de ces protéines, montrant leur capacité à fixer le zinc (ZneB), ou le cuivre et l’argent (SilB). De plus, nous avons résolu la structure cristalline de ZneB à une résolution de 2.8 Å dans la forme apo- et avec un ion zinc fixé. La structure de ZneB possède une architecture générale composée de quatre domaines caractéristiques des MFPs, et la présence du site de coordination au zinc dans une région très flexible à l’interface des domaines β-barrel et membrane proximal. Les modifications structurales que la protéine subit lors de la fixation du zinc on été observée dans le cristal mais aussi en solution, ce qui suggère un rôle actif des MFPs dans le mécanisme d’efflux des métaux, vraisemblablement via la fixation et le relargage de l’ion à l’antiporteur. Les études de sélectivité de transport des antiporteurs ZneA et SilA montre que ces dernières et leurs protéines périplasmiques respectives ont des affinités similaires pour les métaux lourds. De plus, les études de transport ont apportés des arguments en faveur de l’hypothèse de capture cytoplasmique du substrat par l’antiporteur, tandis que la capacité des protéines périplasmiques à fixer les métaux lourds a apporté des arguments en faveur de l’hypothèse de capture périplasmique du substrat par l’antiporteur. Les deux modes de capture pourraient en réalité coexister ;cependant, le débat autour du compartiment cellulaire de capture du substrat par l’antiporteur est complexe et requiert de plus amples efforts afin d’être cerné. / Tripartite resistance nodulation cell division (RND)-based efflux complexes are paramount for multidrug and heavy metal resistance in numerous Gram-negative bacteria. The transport of these toxic compounds out of the cell is driven by the inner membrane proton/substrate antiporter (RND protein) connected to an outer membrane protein to form an exit duct that spans the entire cell envelope. The third component, a membrane fusion protein (MFP) also called periplasmic adaptor protein, is required for the assembly of this complex. However, MFPs are also proposed to play an important active role in substrate efflux. To better understand the role of MFPs in RND-driven efflux systems, we studied ZneB (formerly HmxB) and SilB, the MFP components of the ZneCAB and SilABC heavy metal RND-driven efflux complexes from Cupriavidus metallidurans CH34. We have identified the substrate binding specificity of the proteins, showing their ability to selectively bind zinc (ZneB), or copper and silver cations (SilB). Moreover, we have solved the crystal structure of the apo- and the metal-bound forms of ZneB to 2.8 Å resolution. The structure of ZneB displays a general architecture composed of four domains characteristic of MFPs, and it reveals the metal coordination site at the very flexible interface between the β-barrel and the membrane proximal domains. Structural modifications of the protein upon zinc binding were observed in both the crystal structure and in solution, suggesting an active role of MFPs in substrate efflux possibly through binding and release. The selectivity assays of the antiporter proteins ZneA and SilA demonstrated similar specificities in relation to their cognate MFPs toward heavy metal cations. Moreover, antiporter transport assays provide evidence for cytoplasmic substrate capture by this protein, whereas MFP substrate binding provides evidence for periplasmic substrate capture. Therefore, both modes of capture might co-exist; nevertheless, the substrate capture issue is a complex topic still needing consequent efforts to understand it.
Doctorat en Sciences agronomiques et ingénierie biologique
info:eu-repo/semantics/nonPublished

Das Ziel dieser Dissertation ist die systematische Entwicklung eines weiterführenden Konzeptes zur Fahrer-Fahrzeug Kooperation, dessen Tauglichkeit anhand empirischer Daten evaluiert und im Hinblick auf sein belegbares Potential in Bezug auf bestehende Ansätze bewertet werden soll.Da Annahmen und Prämissen der Mensch-Maschine-Interaktion den Ausgangspunkt bilden, beginnt die dezidierte Auseinandersetzung und begriffliche Differenzierung von Kooperation in eben diesem Kontext und führt folgerichtig zu einer definitorischen Abgrenzung gegenüber existierenden Ansätzen, der Forderung eines spezifischen Rollenverständnisses zur Interaktion sowie der Ableitung konzeptueller Grundbedingungen. Anschließend werden die strukturellen und prozeduralen Merkmale dieser spezifischen Interaktion herausgearbeitet und dazu benutzt, die generellen Attribute von Kooperation zwischen Fahrer und Fahrzeug zu identifizieren. Dafür wurden nachfolgend solche Indikatoren abgeleitet, vermittels derer der unterstellte Gewinn infolge der Kooperation von Fahrer und Fahrzeug kontrolliert und bewertet werden kann.Im Rahmen mehrerer Voruntersuchungen wurden Fahrsituationen identifiziert, die am meisten von einer kooperativen Interaktion zwischen Fahrer und Fahrzeug profitieren würden. Im Ergebnis wurden für die zwei Hauptuntersuchungen das „Überholen auf der Autobahn“ und das „Linksabbiegen auf innerstädtischen Straßen und Landstraßen mit Gegenverkehr“ als Fahrszenarien ausgewählt, die in jeweils einem eigenständigen Experiment mit alternativen Systemvarianten verglichen worden sind. Die Prüfung spezifischer Hypothesen wurde dabei in die prototypische Umgebung eines Fahrsimulators eingebettet. Abschließend werden in dieser Arbeit die Möglichkeiten zur Etablierung und Einbettung dieses Interaktionskonzeptes in den übergreifenden sozio-technischen Kontext aufgezeigt und zukünftige Perspektiven diskutiert.
The aim of this dissertation is to systematically develop a continuative concept of driver-automobile cooperation, to evaluate its suitability on the basis of empirical data, and to value its provable potential in relation to existing approaches.Assumptions and premises regarding the human-machine interaction constitute the starting point of this work. The decisive altercation and notional differentiation of cooperation are explained in just this context, leading logically to a definitional demarcation of existing approaches, the demand of a specific role understanding of the interaction as well as the derivation of conceptual basic conditions. The structural and procedural characteristics of this specific interaction are then elaborated upon and used to identify the general attributes of cooperation between driver and automobile. In the following, such indicators are derived by which the implied profit as a result of cooperation between driver and automobile can be controlled and valued. Within the framework of several preliminary investigations, those driving situations were identified that would profit most from a cooperative interaction between driver and automobile. As a result, the two driving scenarios "Overtaking on Highways" and "Turning Left on Urban and Country Roads with Oncoming Traffic" were utilized in the experiments. Both single scenarios have been compared in independent experiments with regard to alternative system variants. The prove of specific hypotheses was embedded in the prototypical surroundings of a driving simulator. Finally, the possibility of establishing and embedding this interaction concept into the overall socio-technical context will be presented, and future perspectives will be discussed.

Dissertation submitted to the Faculty of Health Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree Master of Science in Medicine (Physiology). Johannesburg, 2012.
The game of golf requires players to strike a ball towards a distant target in as few as possible shots. One key component to the successful completion of this goal is a proficient golf swing. The golf swing is composed of a sequence of highly complex biomechanical movements requiring coordinated body movements and postural control. In addition, walking (a fundamental part of the game of golf) may have interesting effects on golf drive performance however, to date, this is largely unknown. The objective of the study was to identify the physiological and biomechanical variables that predict golf drive performance and to assess the effects of a hole-to-hole distance walk on golf drive performance. Twenty-one amateur golfers volunteered to take part in the study. The golfers were divided into two groups based on their recent average scores: More Competitive Group ((MCG) n=13, scores≤88) and Irregular Social Group ((ISG) n=8, scores>89). Drive distance (resting ball position) and accuracy (perpendicular distance from target) were directly measured. Balance and hand-eye coordination were assessed using a modified stork test and a customised three dimensional maze respectively. Lean mass was determined using bioimpedance. To determine walking effects participants hit ten golf balls and then walked 500m before repeating the tests. Average balance duration of both legs (r=0.45 p=0.048) the left leg (r=0.44 p=0.041) and the right leg (r=0.44 p=0.041) were all significantly correlated to drive distance. The hand and eye coordination task was correlated with total drive distance (r=-0.60 R2=0.36 p=0.008), but was not significantly associated with the centre of hit between the club face and ball. Significant contributors to a physiological model predictive of drive distance (R2=0.667; p=0.001) included age (β=1.228) lean mass percentage (β=1.899) and left leg balance (β=1.542). A corresponding biomechanical model (R2=0.9996; p=0.025; n=5) shows that leading arm angle (β=16.51), left elbow angle (β=-0.265) and lateral bend (β=-1.297) together significantly predict drive distance. Heart rate was significantly elevated following iv the walk for all golfers but was not significantly different between the groups before or after the walk. The MCG had significantly longer drives following the walk (p=0.018). The changes in drive distance were correlated to the changes in right leg balance with eyes closed (r=-0.62 R²=0.38 p=0.003). When considering changes in kinematic variables as a result of the walk, the change in the left knee angle at backswing (r=0.84 R²=0.71 p=0.017) and the right femur aspect angle at contact were correlated to the change in drive distance (r=0.87 R²=0.75 p=0.025). The physiological and biomechanical models described variables that predict golf drive performance, highlighting the importance of balance and the kinematics of the upper body segments during the swing. Furthermore this study identifies the beneficial effects of walking early in a round to golfers of better golf ability and the effects that such a hole-to-hole walk has on the physiological and biomechanical attributes of the golfer.

The term ‘restitution narrative’ describes the hope we all have when illness or accidental impairment befalls us to be returned to a pre-morbid condition of health as soon as possible, and in modern Western society we expect the miracle of restitutions to be mediated by medical science. Medicine is still unable to cure a wide range of illness and disability. For these people the restitution narrative fails. This study attempts to create space between health and illness, the space of the failed patient, within which to explore the iatrogenic and disabling effects on bodies and minds living in a society that has come to expect not to suffer when illness or disability is incurable and chronic. Through the medium of a purpose built website, people who are chronically ill and disabled discussed the ‘wicked issues’ that make lives already challenged unnecessarily difficult. Application of the findings of research in psychobiology is applied to speculate whether health may be worsened by being a failed patient in a culture for which health has become the ultimate good. Ideas of social fuzziology are brought into play to help imagine ways in which the dualities of health and illness, normal and abnormal, are broken down and the normalizing ideologies of medicine resisted.
Doctor of Philosophy (PhD)

The term ‘restitution narrative’ describes the hope we all have when illness or accidental impairment befalls us to be returned to a pre-morbid condition of health as soon as possible, and in modern Western society we expect the miracle of restitutions to be mediated by medical science. Medicine is still unable to cure a wide range of illness and disability. For these people the restitution narrative fails. This study attempts to create space between health and illness, the space of the failed patient, within which to explore the iatrogenic and disabling effects on bodies and minds living in a society that has come to expect not to suffer when illness or disability is incurable and chronic. Through the medium of a purpose built website, people who are chronically ill and disabled discussed the ‘wicked issues’ that make lives already challenged unnecessarily difficult. Application of the findings of research in psychobiology is applied to speculate whether health may be worsened by being a failed patient in a culture for which health has become the ultimate good. Ideas of social fuzziology are brought into play to help imagine ways in which the dualities of health and illness, normal and abnormal, are broken down and the normalizing ideologies of medicine resisted.

碩士
國立臺灣科技大學
電子工程系
99
In the course of driving, sudden disease outbreak often cause traffic accidents. In this study, we designed a wearable photoplethysmography sensor module based on a Programmable System on Chip （PSoC）. It transmits photoplethysmogram （PPG） signal to a smartphone via Bluetooth. On the smartphone, a heart rate （HR） detection algorithm is implemented. When the abnormal HR is detected, the smartphone will use the sound and vibration to warn the driver. At the same time, physiological data and GPS location are also be transmitted to the remote server （monitoring center） via the mobile network, so that the staff on the center can monitor the newest information and understand the driver’s driving status. In order to reduce motion artifact, LED and silicon photodiode are put into the separate magnetic ring and use the transmission method to measure PPG signal on earlobe. The results show the difference in heart beats between the ECG method and our method is 0 in all driving behaviors test. It shows this new PPG sensor can prevent motion artifact effectively and increase accuracy of heart rate detection in driver’s physiological monitoring.

碩士
國立臺灣師範大學
體育研究所
82
The purpose of this study was to investigate the effects of motor-driven exercise on recovery heart rate, ventilation, oxygen uptake and blood lactate removal rate following a maximal exercise. Subjects were fifteen male students with average age, height and weight of 22.0For attaining VO2max, each subject performed a maximal cycling test with progressively increased workloads. Immediately following maximal exercise of 110% VO2max on the bicycle ergometer, all subjects randomly performed one of the recovery treatments, a static rest or a motor driven exercise. Expired air was determined by Sensormedics 2900 metabolic system. 　　Blood samples for determination of lactate concentration were taken at rest, 5th and 15th minute after maximal exercise from an indwelling venous catheter. Data were analyzed by repeated measure analysis of covariance, the results included: 　　1. Recovery heart rates 5th, 10th minute following motor-driven exercise were significantly higher than those of static recovery. 　　2. Ventilation and oxygen uptake 5th, 10th and 15th minute following motor-driven exercise were significantly higher than those of static recovery. 　　3. Blood lactate removal rate following 15minutes of motor-driven exercise was significantly faster than that of static recovery. 　　The results revealed that motor driven recovery maintained higher levels of recovery ventilation, oxygen uptake and heart rate, and thus increase the blood lactate removal rate. Such an elevation in physiological responses may shorten recovery period and improve recovery efficiency following severe physical exercise.

Emerging technologies such as real-time travel information systems and automated vehicles (AVs) have profound impacts on driver decision-making behavior. While they generally have positive impacts by enabling drivers to make more informed decisions or by reducing their driving effort, there are several concerns related to inadequate consideration of cognitive and psychological aspects in their design. In this context, this dissertation analyzes different aspects of driver cognition and psychology that arise from drivers’ interactions with these technologies using physiological data collected in two sets of driving simulator experiments.

This research analyzes the latent cognitive and psychological effects of real-time travel information using electroencephalogram (EEG) data measured in the first set of driving simulator experiments. Using insights from the previous analysis, a hybrid route choice modeling framework is proposed that incorporates the impacts of the latent information-induced cognitive and psychological effects along with other explanatory variables that can be measured directly (i.e., route characteristics, information characteristics, driver attributes, and situational factors) on drivers’ route choice decisions. EEG data is analyzed to extract two latent cognitive variables that capture the driver’s cognitive effort during and immediately after the information provision, and cognitive inattention before implementing the route choice decision.

Several safety concerns emerge for the transition of control from the automated driving system to a human driver after the vehicle issues a takeover warning under conditional vehicle automation (SAE Level 3). In this context, this study investigates the impacts of driver’s pre-warning cognitive state on takeover performance (i.e., driving performance while resuming manual control) using EEG data measured in the second set of driving simulator experiments. However, there is no comprehensive metric available in the literature that could be used to benchmark the role of driver’s pre-warning cognitive state on takeover performance, as most existing studies ignore the interdependencies between the associated driving performance indicators by analyzing them independently. This study proposes a novel comprehensive takeover performance metric, Takeover Performance Index (TOPI), that combines multiple driving performance indicators representing different aspects of takeover performance.

Acknowledging the practical limitations of EEG data to have real-world applications, this dissertation evaluates the driver’s situational awareness (SA) and mental stress using eye-tracking and heart rate measures, respectively, that can be obtained from in-vehicle driver monitoring systems in real-time. The differences in SA and mental stress over time, their correlations, and their impacts on the TOPI are analyzed to evaluate the efficacy of using eye-tracking and heart rate measures for estimating the overall takeover performance in conditionally AVs.

The study findings can assist information service providers and auto manufacturers to incorporate driver cognition and psychology in designing safer real-time information and their delivery systems. They can also aid traffic operators to incorporate cognitive aspects while devising strategies for designing and disseminating real-time travel information to influence drivers’ route choices. Further, the study findings provide valuable insights to design operating and licensing strategies, and regulations for conditionally automated vehicles. They can also assist auto manufacturers in designing integrated in-vehicle driver monitoring and warning systems that enhance road safety and user experience.

碩士
國防大學管理學院
資源管理及決策研究所
100
This study is to explore the effect of weather and conductor on driver’s psychological, physiological responses and driving performance. A driving simulator was used and a total of 20 male subjects participated in the study. The independent variables included weather condition (sunny day, foggy day) and vehicle conductor (involved, not involved), the dependent variables included heart rate (HR), driving task complete time and subjective mental workload (NASA TLX). The results showed that the HR was greatest while driving in foggy day without vehicle conductor. When unexpected situation happened (e.g. a barricade was suddenly placed on a road), the HR was lower while driving with vehicle conductor regardless of the weather condition. Moreover, the complete time was shorter, NASA-TLX score was lower and subjective performance satisfaction was greater in the condition of driving with vehicle conductor. Therefore, transforming from single visual channel resource using to both visual and auditory channel resources using would improve the driver’s concentration on road condition and resulted in driver's mental workload and task complete time reduced.

Geographical species redistributions are among the primary ecological responses to global climate change. In subtropical and temperate oceans, the predominant climate-driven distributional responses are range extensions, which outpace warm, trailing range-edge contractions by four times over on average. Climate-driven species range extensions have unpredictable consequences for recipient communities and the provision of associated ecosystem services, presenting a critical concern for management. However, the rates of species’ responses to changing climate vary considerably, preventing accurate forecasts of range extensions based on climate data alone. Most of this variability appears to arise from the dynamic physiological and behavioural traits which underpin ectothermic species’ responses to temperature and other habitat changes. Predictive capacity can be increased by understanding and incorporating these biological mechanisms from which range extensions emerge. Pursuit of key mechanisms spans a growing body of observational, experimental, and modelling efforts as well as theoretical frameworks. These domain-specific approaches have yielded considerable insights into aspects of range extensions and their mechanisms. However, limited integration across domains and inadequate ecological realism in general have hindered efforts to develop a mechanistic understanding of range extensions. At the typically ‘cool’, leading range edges pertinent to range extensions, both abiotic and biological conditions likely diverge from historical ranges. For example, water temperatures vary seasonally and over even small distances which virtually all mobile animals will select for non-randomly. Furthermore, range-extending individuals are likely to vary in behavioural and physiological responses to temperature due to plasticity and selection. Thus, research assuming average regional range-edge temperatures and population mean traits do not accurately reflect the conditions in which range extensions occur. However, contemporary range extension fronts provide a unique opportunity to investigate these conditions. Here, I integrated laboratory-based experimental and field-based observational approaches to examine the thermal physiological performance, movement behaviour, and field energetics of snapper Chrysophrys auratus (Forster 1801) at the extreme poleward front of the species’ ongoing range extension into southeast Tasmania. Specifically, I i) identify the physiological performances, behaviours, and their interactions relevant to persistence at range edge conditions; ii) test hypotheses regarding the mechanisms underpinning range extensions at the range limit of snapper; iii) and address knowledge gaps for management of this important teleost predator and its emerging range-edge fishery. First, I experimentally compared swimming and aerobic metabolism performances of snapper after range-optimal (20 °C) and ambient range-edge winter temperature acclimation (10 – 12 °C) with swim tunnel respirometry and establish baseline allometric scaling relationships for this key species. I tested and found little support for performance limitation arising from aerobic capacity insufficiency, a prominent hypothesis in the field. Moreover, I found that while range front acclimation curtails top end sustained swimming and metabolic performance, low speed swimming energetic efficiency increases, and maintenance costs declined. However, the degree to which these declines could pose a mechanism of ecological limitation depends on demands on these performances in the field. Next, I characterised the movements of 30 range front snapper with passive acoustic telemetry to determine the degree to which snapper are able to behaviourally thermoregulate and whether novel patterns of movement behaviour have emerged in this population. Range-front snapper are resident to small areas of key warm inshore habitat in summer which decline to unfavourably cold temperatures in winter. However, snapper exhibit a novel inshore-offshore seasonal migration strategy, selecting optimal temperatures across at least 45 km. I demonstrate aspects of snapper ecology of key management concern such as high seasonal site fidelity to predictable localised habitats, and I identify thermal limitation of nursery habitat as a potential mechanism of distributional limitation. I also present new methods to characterise daily patterns of telemetry data. Finally, I integrated lab and field approaches to characterise field acceleration and swimming energetics of ten snapper with accelerometer acoustic transmitters. Contrary to a commonly assumed monotonic relationship between field acceleration and temperature optimality, snapper acceleration peaked at moderate suboptimal temperatures during seasonal migration-related behaviour. Swim speeds and associated metabolic demands were predicted from transmitter acceleration with functions developed from experimental swim tunnel calibration of seven snapper implanted with transmitters. Swimming activity-related demands on aerobic metabolism in the field did not increase at the most sub-optimal temperatures, incongruent with the hypothesis that sub-optimal temperatures drive aerobic scope budgeting conflicts. Energetic efficiency did not appear to have a predominant effect in shaping volitional swim speeds. My work realises a long-proposed, integrated approach to range extensions reveals the complex, dynamic interplay of behaviour, performance, and environmental variability at root of climate-driven range extensions. I have demonstrated novel behaviour can cause extended range ecology to deviate from expected habitat relationships (i.e., those underpinning correlative distribution models), and by integrating experimental performance data, greatly increased the inference that can be drawn from field-based work on thermal limitation. For example, this approach has enabled the test of several hypotheses generated from theoretical frameworks of thermal limitation: aerobic scope does not appear to be a limiting factor at a species’ distributional limit; In situ body acceleration did not serve as a suitable as a proxy for thermal performance because the relative use of performance wasn’t greatest at the most physiologically favourable temperatures and instead varied with the demands of adaptive seasonal behaviours. These results provide the data needed for bioenergetic modelling that can provide the basis for forecasts of this range-extending species’ demography and ecological interactions, critical for management of this global phenomenon. Finally, in situ investigations of range extensions are rare in large part due to logistical constraints. The success of this study illustrates the importance of engaging with stakeholders, in this case the Tasmanian recreational fishing community, enabling obtaining experimental animals, and facilitating the generation of hypotheses and effective design of field studies.