Academic literature on the topic 'Action Observation System'
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Journal articles on the topic "Action Observation System"
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Mattiassi, Alan D. A., Sonia Mele, Luca F. Ticini, and Cosimo Urgesi. "Conscious and Unconscious Representations of Observed Actions in the Human Motor System." Journal of Cognitive Neuroscience 26, no. 9 (September 2014): 2028–41. http://dx.doi.org/10.1162/jocn_a_00619.
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Action observation activates the observer's motor system. These motor resonance responses are automatic and triggered even when the action is only implied in static snapshots. However, it is largely unknown whether an action needs to be consciously perceived to trigger motor resonance. In this study, we used single-pulse TMS to study the facilitation of corticospinal excitability (a measure of motor resonance) during supraliminal and subliminal presentations of implied action images. We used a forward and backward dynamic masking procedure that successfully prevented the conscious perception of prime stimuli depicting a still hand or an implied abduction movement of the index or little finger. The prime was followed by the supraliminal presentation of a still or implied action probe hand. Our results revealed a muscle-specific increase of motor facilitation following observation of the probe hand actions that were consciously perceived as compared with observation of a still hand. Crucially, unconscious perception of prime hand actions presented before probe still hands did not increase motor facilitation as compared with observation of a still hand, suggesting that motor resonance requires perceptual awareness. However, the presentation of a masked prime depicting an action that was incongruent with the probe hand action suppressed motor resonance to the probe action such that comparable motor facilitation was recorded during observation of implied action and still hand probes. This suppression of motor resonance may reflect the processing of action conflicts in areas upstream of the motor cortex and may subserve a basic mechanism for dealing with the multiple and possibly incongruent actions of other individuals.
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Hodges, Nicola J. "Observations on Action-Observation Research: An Autobiographical Retrospective Across the Past Two Decades." Kinesiology Review 6, no. 3 (August 2017): 240–60. http://dx.doi.org/10.1123/kr.2017-0016.
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When we watch other people perform actions, this involves many interacting processes comprising cognitive, motor, and visual system interactions. These processes change based on the context of our observations, particularly if the actions are novel and our intention is to learn those actions so we can later reproduce them, or respond to them in an effective way. Over the past 20 years or so I have been involved in research directed at understanding how we learn from watching others, what information guides this learning, and how our learning experiences, whether observational or physical, impact our subsequent observations of others, particularly when we are engaged in action prediction. In this review I take a historical look at action observation research, particularly in reference to motor skill learning, and situate my research, and those of collaborators and students, among the common theoretical and methodological frameworks of the time.
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Chad Woodruff, Christopher, and Shannon Maaske. "Action execution engages human mirror neuron system more than action observation." NeuroReport 21, no. 6 (April 2010): 432–35. http://dx.doi.org/10.1097/wnr.0b013e3283385910.
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Modroño, Cristián, Sergi Bermúdez, Mónica Cameirão, Fábio Pereira, Teresa Paulino, Francisco Marcano, Estefanía Hernández-Martín, et al. "Is it necessary to show virtual limbs in action observation neurorehabilitation systems?" Journal of Rehabilitation and Assistive Technologies Engineering 6 (January 2019): 205566831985914. http://dx.doi.org/10.1177/2055668319859140.
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Introduction Action observation neurorehabilitation systems are usually based on the observation of a virtual limb performing different kinds of actions. In this way, the activity in the frontoparietal Mirror Neuron System is enhanced, which can be helpful to rehabilitate stroke patients. However, the presence of limbs in such systems might not be necessary to produce mirror activity, for example, frontoparietal mirror activity can be produced just by the observation of virtual tool movements. The objective of this work was to explore to what point the presence of a virtual limb impacts the Mirror Neuron System activity in neurorehabilitation systems. Methods The study was conducted by using an action observation neurorehabilitation task during a functional magnetic resonance imaging (fMRI) experiment with healthy volunteers and comparing two action observation conditions that: 1 – included or 2 – did not include a virtual limb. Results It was found that activity in the Mirror Neuron System was similar during both conditions (i.e. virtual limb present or absent). Conclusions These results open up the possibility of using new tasks that do not include virtual limbs in action observation neurorehabilitation environments, which can give more freedom to develop such systems.
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Southgate, Victoria, Mark H. Johnson, Tamsin Osborne, and Gergely Csibra. "Predictive motor activation during action observation in human infants." Biology Letters 5, no. 6 (August 12, 2009): 769–72. http://dx.doi.org/10.1098/rsbl.2009.0474.
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Certain regions of the human brain are activated both during action execution and action observation. This so-called ‘mirror neuron system’ has been proposed to enable an observer to understand an action through a process of internal motor simulation. Although there has been much speculation about the existence of such a system from early in life, to date there is little direct evidence that young infants recruit brain areas involved in action production during action observation. To address this question, we identified the individual frequency range in which sensorimotor alpha-band activity was attenuated in nine-month-old infants' electroencephalographs (EEGs) during elicited reaching for objects, and measured whether activity in this frequency range was also modulated by observing others' actions. We found that observing a grasping action resulted in motor activation in the infant brain, but that this activity began prior to observation of the action, once it could be anticipated. These results demonstrate not only that infants, like adults, display overlapping neural activity during execution and observation of actions, but that this activation, rather than being directly induced by the visual input, is driven by infants' understanding of a forthcoming action. These results provide support for theories implicating the motor system in action prediction.
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Bolliet, Olivier, Christian Collet, and André Dittmar. "Observation of Action and Autonomic Nervous System Responses." Perceptual and Motor Skills 101, no. 1 (August 2005): 195–202. http://dx.doi.org/10.2466/pms.101.1.195-202.
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Observing somebody performing an action has been shown to elicit neuronal activity in the premotor cortex. This paper investigated physiological effect of observing an effortful action at the peripheral level. As Autonomic Nervous System responses reflect central nervous system processes such as movement planning and programming, it was expected that observing an action would elicit a pattern of ANS responses matching those recorded during actual movement. 12 male subjects, ages 23 to 28 years ( M = 25.5, SD = 1.9), were selected as they were experienced in weight lifting. They were asked to observe a squat movement followed by returning to the upright position under 3 different conditions: (i) observation of actual movement performed by somebody else, (ii) observation of a video of the subject himself (first-person video), and (iii) observation of a video of somebody else performing the same movement (third-person video). Moreover, each movement was observed when performed at 50% and 90% of each participant's personal best mark (% of the highest weight which could be lifted). Three ANS parameters were continuously recorded: skin resistance, temperature and heart rate. ANS responses varied as a function of movement intensity: autonomic responses recorded during movement observation at 90% were significantly higher and longer than those recorded during movement observation at 50%. Thus, autonomic responses were linked to the amount of observed effort. Conversely, no difference was found among the three conditions of observation. ANS responses from observation of actual movement were shown to resemble those recorded under the two conditions of video observation.
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BOLLIET, OLIVIER. "OBSERVATION OF ACTION AND AUTONOMIC NERVOUS SYSTEM RESPONSES." Perceptual and Motor Skills 101, no. 5 (2005): 195. http://dx.doi.org/10.2466/pms.101.5.195-202.
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Ray, Matthew, Deborah Dewey, Libbe Kooistra, and Timothy N. Welsh. "The relationship between the motor system activation during action observation and adaptation in the motor system following repeated action observation." Human Movement Science 32, no. 3 (June 2013): 400–411. http://dx.doi.org/10.1016/j.humov.2012.02.003.
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Kourtis, Dimitrios, Natalie Sebanz, and Günther Knoblich. "Favouritism in the motor system: social interaction modulates action simulation." Biology Letters 6, no. 6 (June 23, 2010): 758–61. http://dx.doi.org/10.1098/rsbl.2010.0478.
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The ability to anticipate others' actions is crucial for social interaction. It has been shown that this ability relies on motor areas of the human brain that are not only active during action execution and action observation, but also during anticipation of another person's action. Recording electroencephalograms during a triadic social interaction, we assessed whether activation of motor areas pertaining to the human mirror-neuron system prior to action observation depends on the social relationship between the actor and the observer. Anticipatory motor activation was stronger when participants expected an interaction partner to perform a particular action than when they anticipated that the same action would be performed by a third person they did not interact with. These results demonstrate that social interaction modulates action simulation.
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Bates, Alan T., Tina P. Patel, and Peter F. Liddle. "External Behavior Monitoring Mirrors Internal Behavior Monitoring." Journal of Psychophysiology 19, no. 4 (January 2005): 281–88. http://dx.doi.org/10.1027/0269-8803.19.4.281.
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Abstract: The discovery of mirror neurons in monkeys has reshaped thinking about how the brain processes observed actions. There is growing evidence that these neurons, which show similar firing patterns for action execution and observation, also exist in humans. Many parts of the motor system required to perform a specific action are activated during the observation of the same action. We hypothesized that behavior monitoring that occurs during action execution is mirrored during action observation. To test this, we measured error negativity/error-related negativity (Ne/ERN) while participants performed and observed a Go/NoGo task. The Ne/ERN is an event-related potential that is thought to reflect an error detection process in the brain. In addition to finding an Ne/ERN for performed errors, we found that an Ne/ERN was also generated for observed errors. The Ne/ERN for observed errors may reflect a system that plays a key role in imitation and observational learning.
Dissertations / Theses on the topic "Action Observation System"
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Moutsopoulou, Karolina. "Automaticity of the human action observation system : modulations by attention and action planning." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608711.
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Tia, Banty. "Couplage perception-action et équilibre postural : approche fondamentale. Application de l'observation pour le réentrainement chez les sujets agés." Thesis, Dijon, 2011. http://www.theses.fr/2011DIJOS027.
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L’imitation volontaire est établie comme l’un des modes principaux d’acquisition des habiletés motrices. Il existe également une autre forme d’imitation, automatique et involontaire, étudiée initialement en psychologie sociale du fait de son interaction étroite avec les comportements pro-sociaux. Récemment, et sous l’influence de travaux des années 1990 mettant en lumière des substrats neuronaux communs à l’observation et à l’exécution du mouvement, les recherches scientifiques se sont concentrées sur cette notion d’imitation automatique et ont investigué, via différents paradigmes expérimentaux, les effets de facilitation et d’interférence entre mouvements observés et exécutés. Le travail réalisé dans le cadre de cette thèse vise à améliorer notre compréhension des mécanismes de contagion motrice et à identifier leurs applications possibles au réentraînement moteur. Dans une première étude, nous avons évalué l’impact de l’observation de mouvements de déséquilibre sur le balancement postural d’observateurs jeunes (24,5 ± 5 ans), sans troubles posturaux. Le contrôle de l’équilibre orthostatique fait principalement intervenir des structures sous-corticales pour le maintien du tonus postural et l’intégration multisensorielle. Ces substrats neuronaux seraient, de la même manière que les fonctions végétatives indépendantes du contrôle volontaire, plus facilement contaminés par les mouvements observés. Cependant, l’observation d’un déséquilibre sollicite également des mécanismes de régulation posturale, qui restreignent le balancement de l’observateur et se surajoutent à des processus inhibiteurs prévenant l’imitation compulsive des mouvements observés. Par conséquent, ce paradigme expérimental nous a permis de tester les limites des effets de contagion à partir d’une situation où les processus inhibiteurs et régulateurs de la posture étaient fortement sollicités. Cette étude nous a conduits à mettre en évidence une contamination du balancement postural des sujets par le déséquilibre observé, ce qui a confirmé l’importance et la prédominance des processus d’imitation. Ce résultat soulève des questions importantes en termes d’applications au réentraînement moteur chez les patients souffrant de troubles posturaux, en particulier chez les personnes âgées qui présentent une altération de leurs fonctions de stabilisation. En effet, si l’observation d’un déséquilibre conduit à une réaction de contagion motrice, il est vraisemblable qu’elle sollicite également des fonctions inhibitrices et régulatrices permettant la stabilisation de l’observateur. La visualisation répétée d’un déséquilibre peut-elle alors conduire à une amélioration de la stabilisation chez les personnes à risque ? Pour étudier cette question, il serait nécessaire de répéter ce protocole chez le public cible - les réponses pouvant être modulées par l’âge et les aptitudes motrices des personnes. Notre seconde étude visait à évaluer l’impact du répertoire moteur sur les réactions de contagion motrice. S’il est admis que le système moteur (contraintes biomécaniques, niveau d’expertise) affecte les processus perceptifs, son effet sur les réactions d’imitation automatique a été peu étudié. Nous avons analysé les réactions posturales d’observateurs jeunes (24,2 ± 3,7 ans), sains, face à des séquences de déséquilibre antéro-postérieur et médio-latéral. Les stratégies d’équilibration posturale sont associées à des contraintes différentes selon ces deux axes, avec une symétrie médio-latérale et une asymétrie antéropostérieure – asymétrie résultant d’une position du centre de masse en avant de l’articulation de la cheville, qui induit une sollicitation accrue des muscles du plan postérieur pour la stabilisation posturale. Un impact du système moteur sur le processus de contagion serait donc susceptible de se traduire par des réactions posturales différentes dans nos deux conditions d’observation. etcVoluntary imitation is known as a major means of acquisition of motor skills. Besides, another form of imitation, automatic and involuntary, was initially more extensively studied in social psychology, perhaps because of its close interaction with prosocial behaviors. Recently, there was a renewal of interest in automatic imitation, following research works of the 1990s that highlighted common neural substrates for movement observation and execution. In this context, scientific studies started, through various experimental paradigms, to investigate facilitation and interference effects between observed and executed movements. Research work presented in this thesis aims to improve our understanding of the mechanisms involved in motor contagion and to identify their possible application to motor retraining. For this purpose, we evaluated, in our first study, the impact of observation of postural imbalance on body sway of young (24.5 ± 5 years), healthy observers. Postural control mainly relies on subcortical structures for maintaining postural tonus and ensuring multisensory integration. Similarly to vegetative functions that are independent of voluntary control, these neural substrates would be more easily contaminated by observed movements. However in response to observed imbalance, postural regulation mechanisms, superimposed to inhibitory processes that prevent compulsive imitation, restrain observers’ disequilibrium. Therefore, this experimental paradigm enabled us to test the limits of contagion mechanisms in a situation highly soliciting inhibitory and regulation processes. Our results led us to highlight a contagion effect of observed imbalance on subjects’ postural sway, which confirmed the importance of imitation processes. These results raise an important question in terms of applications for movement retraining in patients with postural disorders, more specifically in elderly patients with impaired stabilization functions. In effect, if observation of postural imbalance leads to a motor contagion response, it is also likely to solicit regulatory and inhibitory functions for observers’ postural stabilization. Thus, could repeated observation of such disequilibrium movements lead to an improvement of stabilization functions for subjects with postural deficits? To investigate this question, it will be necessary to repeat this protocol with the target population, since observers’ response is likely to vary with age and motor competences. To complete this work, we conducted a second study to assess the impact of the motor repertoire on motor contagion responses. Although it is widely accepted that the motor system (biomechanical constraints, level of expertise) affects perceptual processes, its effect on imitative responses has been little studied. We analyzed postural reactions of young (24.2 ± 3.7 years), healthy observers when presented with sequences of anteroposterior and medio-lateral imbalance. Postural equilibration strategies are associated with different constraints along these two axes, with a medio-lateral symmetry and an anteroposterior asymmetry – this latter asymmetry results from a location of the center of mass ahead of the ankle joint, which induces an increased solicitation of muscles from the posterior plane for stabilization. An impact of the motor system on the contagion process could therefore appear in the form of different postural responses in our two observation conditions. Our results indicated a greater contagion effect during observation of anteroposterior compared to medio-lateral imbalance. Postural contagion is therefore conditioned by observers’ equilibration strategy. In our third study, we considered using this contagion effect for perceptual training aimed at the maintenance and improvement of elderly subjects’ motor performances. The issue of an observational training device is especially relevant when considering people for whom physical exercise is limited due to fatigue or pain.etc
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Bowyer, Sarah Elizabeth. "Participatory mapping as an approach for health services co-planning : finding the local voice in the rural context." Thesis, University of the Highlands and Islands, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238533.
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A key factor to the Scottish Governments' public policy and public service reconfiguration is collaborative working between service providers and service users in a framework of co-production. A second key factor in this reform is a place-based approach. Despite this rhetoric of co-production of health services having been used for some time in health policy, and considering the numerous interpretations of the meaning of both co–production and 'place' in the academic and professional literature, how rural dwellers experience rurality in terms of places and space, and how this may in turn affect health and interactions with co-production, remains underrepresented in health policy planning. In light of changes in health service provision, rural health care poses itself as a potentially emotive and sometimes volatile topic. A co-productive approach may encourage understanding, acceptance and better usage of health services and neighbourhood resources, by the residents registered as patients with local medical practices. This doctoral research study considered the use of participatory mapping techniques to generate, gather and capture the local voice of residents from two rural Scottish communities, regarding the self-perception of their health in relation to the place they call home. Through a participatory action research approach, using iterative co-design, residents were asked how their environment impacted on their health, and in particular their cardiovascular health. Qualitative data were collected through participatory mapping techniques and co- analysed using a thematic analysis process. The application of the concept of therapeutic landscapes revealed the importance of the 'sense of place' and its impact on health, along with the physical, social and cultural environmental aspects traditionally considered in public health disciplines. Results were digitised using geographic information systems (GIS) to illustrate the interactions between place, people and health, through a relational lens. This research demonstrates a working example of how, drawing from the discipline of health geography, a place based approach can make an important contribution to rural health service co- planning within a co-production framework.
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Lapenta, Olivia Morgan. "Efeito da neuromodulação em ritmo mu durante observação e mentalização de movimentos biológicos e não-biológicos." Universidade Presbiteriana Mackenzie, 2012. http://tede.mackenzie.br/jspui/handle/tede/1584.
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The Mental Simulation theory suggests activation of the motor network during imagery and execution of movements, similarly to the activation during observation and execution of actions, which is mediated by the Mirror Neuron System. This activation can be measured using eletroencefalography register of Mu rhythm suppression. It is propose that motor network activation and therefore increase of cortical excitability at primary motor cortex and Mu dessynchronization are due to premotor Miror-Neuron System inputs. Transcranial direct current stimulation is a neuromodulation technique that induce facilitation and inhibition of neural firing leading to enhance or decrease in cortical excitability, respectively. Thus, we propose to evaluate the polarity dependent effects of this technique in the Mu rhythm during biological and non-biological movements observation and imagery tasks. Therefore we applied anodal, cathodal and sham stimulation in 21 male subjects (mean age 23.8+3,06), over left primary motor cortex (2mA for 20min) and immediately after we registered the electroencephalography considering the electrodes C3, C4 and surrounding C3 and C4 and Cz. Analyses of C3 and C4 showed significant effects according to Movement (p=0.005), and also for the interactions between type of stimulation and hemisphere (p=0.04) and type of stimulation, movement and hemisphere (p=0.02). Surrounding electrodes analyses revealed significant effect for the interaction between stimulation type, task condition and movement type (p=0.03). Thus, the main findings of this study were i. Mu suppression for biological movement (in both imagery and observation) of the hand region in the contralateral hemisphere after sham stimulation, ii. reverse effect for the surrounding electrodes during imagery condition and iii. polarity-dependent neuromodulation of the Mu rhythm. The results are discussed considering focal ERD/ surrounding ERS according to the type of task. We concluded that there are contralateral focal Mu dessynchronization during observation and imagery of biological movements together with syncronizarion of the motor areas not involved in the task only for the imagery condition and that transcranial direct current stimulation has a significant effect under the entire electrode and according to the applied polarity. The use of transcranial direct current stimulation followed by observation and imagery tasks might be an interesting intervention strategy for disturbances involving motor ability impairment as well as deficits related to imitation and comprehension of other s actions.
A teoria de simulação mental sugere ativação da rede neural motora durante mentalização e execução de movimentos, de maneira análoga à ativação em observação e execução de ações, o que é mediado pelo Sistema de Neurônios-Espelho. Esta ativação pode ser mensurada por supressão do ritmo Mu registrado por eletroencefalografia. É proposto que a ativação de áreas motoras e, portanto, o aumento de excitabilidade cortical em cortex motor primário e a dessincronização do ritmo Mu ocorram em consequência de insumo proveniente do Sistema Neurônios-Espelho pré-motor. A estimulação transcraniana por corrente contínua consiste numa técnica de neuromodulação por facilitação e inibição de disparo neuronal levando a aumento e redução de excitabilidade cortical, respectivamente. Assim, foi proposto avaliar os efeitos polaridade dependentes desta técnica sobre ritmo Mu durante tarefas de observação e mentalização de movimentos biológicos e não biológicos. Para tal, aplicamos estimulação anódica, catódica e placebo em 21 homens destros (idade média de 23.8+3,06), sobre córtex motor primário esquerdo (2mA por 20min) e, em seguida foi feito o registro eletroencefalográfico considerando os eletrodos C3, C4 e entorno de C3 e C4 e Cz. A análise de C3 e C4 apresentou efeitos significativos quanto ao tipo de Movimento (p=0.005) e ainda quanto as interações entre tipo de estimulação e hemisfério (p=0.04) e tipo de estimulação, de movimento e hemisfério (p=0.02). A análise dos eletrodos do entorno revelou efeito significativo para a interação entre tipo de estimulação, condição da tarefa e tipo de movimento (p=0.03). Assim, os principais achados do estudo foram i. supressão de Mu para movimento biológico (em mentalização e observação) da região da mão em hemisfério contralateral após estimulação placebo, ii. efeitos inversos para eletrodos de entorno em condição de mentalização e iii. neuromodulação polaridade dependente de ritmo Mu. Os resultados de oscilação de Mu são discutidos considerando ERD focal/ ERS entorno de acordo com o tipo de tarefa. Concluímos que há dessincronização contralateral focal de Mu durante observação e mentalização de movimentos biológicos, acompanhada por sincronização de áreas motoras não envolvidas na tarefa apenas na condição de mentalização e que a estimulação transcraniana por corrente contínua tem efeito sob toda a superfície do eletrodo e difere de acordo com a polaridade aplicada. O uso da estimulação transcraniana por corrente contínua combinada com tarefas de observação e mentalização pode conferir uma estratégia interessante de intervenção em distúrbios envolvendo comprometimento das habilidades motoras bem como comprometimento de habilidades de imitação e compreensão das ações do outro.
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DI, NUZZO CHIARA. "L'apprendimento motorio in persone sane e Parkinsoniane: L'effetto combinato dell'esperienza multimodale e di neurostimolazione." Doctoral thesis, Università Cattolica del Sacro Cuore, 2015. http://hdl.handle.net/10280/6211.
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L'obiettivo principale del lavoro è stato di valutare il ruolo della neurostimolazione e della multimodalità (intesa come la presentazione visiva di un modello che esegue un movimento assieme a una musica sincrona) nell’apprendimento motorio, indagando sia gli effetti sugli adulti sani sia su pazienti affetti da Morbo di Parkinson (MP). Per raggiungere tale obiettivo, sono state condotte tre ricerche sperimentali e longitudinali, utilizzando diversi strumenti, come tDCS, biofeedback e KinectTM.
Partendo da una sistematica revisione della letteratura nel campo della riabilitazione neuromotoria, sono state identificate tre forme di trattamento che sembrano efficaci contro i sintomi motori del MP. Tuttavia, pur riconoscendo la loro efficacia, non sono mai stati combinati nella pratica riabilitativa: l’Action Observation Learning (basato sulla teoria del sistema dei neuroni specchio), la neurostimolazione anodica non-invasiva sulla zona motoria primaria e l'uso della musica.
I risultati dimostrano un chiaro sostegno della multimodalità e della neuro stimolazione nella fase di encoding e un loro supporto nel migliorare le funzioni motorie, anche a distanza di un mese. Questo lavoro offre nuove indicazioni per lo sviluppo di approcci innovativi ed efficaci nel campo dell’apprendimento motorio.The main objective was to assess the role of neurostimulation and multimodality (namely the presentation of a visual model together with a synchronized musical track) in motor learning, by considering both healthy adults and Parkinsonian patients (PD). In order to achieve this goal, three experimental and longitudinal studies were carried out, using different tools such as tDCS, biofeedback and KinectTM. Starting with a systematic review, three innovative approaches which seem to be effective in treating the motor symptoms of PD, were identified. However, while recognizing the effectiveness of these three promising approaches, they have never been combined: Action Observation Learning (based on the theory of mirror neuron system), the non-invasive anodal neurostimulation on the primary motor area and the use of music. The results showed a clear support of multimodality and neurostimulation during the encoding phase and in improving motor functions, even after one month. This work provides new suggestions for innovative and effective treatments in motor learning field.
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Van, Gorp Jérémy. "Diagnostic et observation d'une classe de systèmes dynamiques hybrides. Application au convertisseur multicellulaire série." Phd thesis, Université de Valenciennes et du Hainaut-Cambresis, 2013. http://tel.archives-ouvertes.fr/tel-00933659.
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Cette thèse s'intéresse au diagnostic et à l'observation de systèmes linéaires à commutations et à l'application au convertisseur multicellulaire série. L'objectif est de proposer des solutions pour des sous-systèmes non-observables au sens classique et dont des fautes continues ou discrètes peuvent être présentes. Après la présentation d'un état de l'art sur les techniques d'observation et de diagnostic pourles systèmes à commutations, le mémoire est scindé en deux parties. La première partie propose, d'une part, une stratégie d'estimation des états discret et continu d'un système linéaire à commutation soumis à une entrée inconnue. Un observateur hybride basé sur la théorie des modes glissants d'ordre supérieur est développé. D'autre part, deux procédures de diagnostic sont présentées. La première combine un observateur hybride et un diagnostiqueur pour détecter une faute continue. Pour la seconde, un diagnostic actif est défini sur la base de la théorie du test afin de détecter et d'isoler une faute discrète. Dans la seconde partie de ce mémoire, les étapes de la réalisation d'un convertisseur multicellulaire sont détaillées. Ensuite, un chapitre est dédié à la validation des approches théoriques d'observation et de diagnostic sur le convertisseur à trois cellules. Un observateur est synthétisé afin d'estimer les tensions des capacités. Les deux procédures de diagnostic sont appliquées pour la détection d'une variation des valeurs des capacités et le diagnostic de cellules bloquées. Enfin, une commande binaire pour le convertisseur est proposée. L'application de cette stratégie permettra, par la suite, la commande tolérante aux fautes du convertisseur.
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Superina, Giulia. "Observation de noyaxu actifs de galaxies de type "blazar" avec les téléscopes H. E. S. S. : caractérisation de la variabilité au TeV du blazar PKS 2155-304." Palaiseau, Ecole polytechnique, 2008. http://www.theses.fr/2008EPXX0068.
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Prokoph, Heike. "Observations and modeling of the active galactic nucleus B2 1215+30 together with performance studies of the ground-based gamma-ray observatories VERITAS and CTA." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2013. http://dx.doi.org/10.18452/16844.
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Das Gebiet der bodengebundenen Gamma-Astronomie bietet Zugang zu Photonen im TeV-Energiebereich und hat sich in den letzten Jahrzehnten vor allem durch den Erfolg der abbildenden atmosphärischen Cherenkov-Technik profiliert. In dieser Arbeit werden zwei dieser Cherenkov-Teleskop-Systeme, VERITAS und das zukünftige CTA, mit Hilfe von Monte-Carlo-Simulationen in Hinblick auf deren Sensitivität auf hochenergetische Gammastrahlung (E > 50 GeV) untersucht. Besonderes Augenmerk wird hierbei auf die Beobachtungsmöglichkeit mit CTA unter Mondlicht gelegt. Es wird gezeigt, dass dadurch eine Beobachtungszeitverlängerung um etwa 30% ohne signifikante Sensitivitätsverluste erreicht werden kann, was besonders wichtig für zeitlich variable Quellen ist. Eine dieser variablen Quellklassen sind aktive Galaxienkerne, welche zur Zeit etwa ein Drittel der bekannten hochenergetischen Gammastrahlungsquellen repräsentieren. Die meisten davon sind Blazare, deren Emission durch nicht-thermische Strahlung aus gebündelten Strömen von Materie und Energie (sogenannten Jets) dominiert wird. Diese Jets breiten sich mit annähernd Lichtgeschwindigkeit aus und sind in Sichtlinie des Betrachters ausgerichtet. Der Blazar B2 1215+30 wurde zwischen 2008 und 2012 mit VERITAS fast 100 Stunden beobachtet. Die Datenanalyse, welche in dieser Arbeit präsentiert wird, weist die Quelle mit einer Signifikanz von neun sigma nach und offenbart Langzeitvariabilität mit einem hellen Flusszustand im Jahr 2011. Multi-Wellenlängen-Daten werden verwendet um die spektrale Energieverteilung von B2 1215+30 zu konstruieren, welche gut mit einem leptonischen Ein-Zonen-Modell beschrieben werden kann. Das verwendete Modell wird im Detail vorgestellt und mögliche Einschränkungen an den Modellparameterraum untersucht. Die Ergebnisse der Modellierung von B2 1215+30 werden diskutiert und in Zusammenhang mit anderen bekannten hochenergetischen Gammastrahlen-Blazaren gesetzt.Ground-based gamma-ray astronomy, which provides access to photons in the TeV energy range, has been a rapidly developing discipline over the past decades. In this thesis, the performance of the current- and next-generation imaging atmospheric Cherenkov telescopes VERITAS and CTA is evaluated using Monte Carlo simulations. Special emphasis is given to the possible extension of the duty cycle of CTA. It is shown that an increase of about 30% in observation time can be achieved through operation under partial moonlight without significant losses in performance. The increased observation time is especially important when studying astronomical objects which are variable at very high energies (VHE; E>50 GeV), such as active galactic nuclei (AGN), as this allows the extension of monitoring or multi-wavelength campaigns on these occasionally flaring sources. AGN represent to date about one third of the population of known VHE gamma-ray sources. Most of them are blazars, whose emission is dominated by non-thermal radiation of relativistic jets closely aligned to the line of sight of the observer. The blazar B2 1215+30 has been observed by VERITAS for nearly 100 hours between 2008 and 2012. The data analysis presented in this thesis yields a detection significance of 9.0 sigma and shows long-term variability with a relatively bright flux state in 2011. Multi-wavelength data are used to construct the spectral energy distribution of B2 1215+30 which is well described by a one-zone leptonic model. The model is presented in detail and possible constraints are investigated. The results of the modeling are discussed and put in context with other VHE-detected blazars.
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Mohamed, Sagayar Moussa. "Action du professeur et pratiques de formation : analyses en classes de cours préparatoires et dans une Cellule d’Animation Pédagogique, dans le contexte du Niger." Thesis, Rennes 2, 2011. http://www.theses.fr/2011REN20045/document.
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Notre travail de recherche porte sur l’analyse de l’action du professeur et ses interactions avec les élèves dans le domaine spécifique de l’étude du numérique en Cours Préparatoires. L’objectif de notre thèse est d’analyser l’action du professeur et ses pratiques didactiques en classes, et formatives dans une Cellule d’Animation Pédagogique. La première partie comporte une présentation du contexte socio économique et éducatif du Niger. Nous nous interrogeons ensuite sur les pratiques professorales permettant ou non aux élèves de prendre de réelles responsabilités par rapport aux savoirs, et sur la pertinence du travail de conception collective de séances. Dans la deuxième partie, nous exposons nos outils théoriques, les travaux antérieurs en lien avec nos objets de recherche, et la problématique générale de notre travail. La troisième partie est consacrée à la démarche méthodologique qui fonde notre étude sur l’analyse des manuels, des vidéos de classe et les observations in situ. La quatrième partie examine les ressources mathématiques utilisées à l’écoleprimaire au Niger, en interrogeant l’influence de ces ressources sur les pratiques habituelles des professeurs enquêtés. Les cinquième et sixième parties analysent les séances empiriques en termes de topogénèse, et de recours aux systèmes sémiotiques pour étudier le savoir en jeu dans les situations didactiques. Dans la septième partie, nous proposons un dispositif innovant de formation continue sur la conception collective de leçons dans une CAPED. En conclusion, dans une huitième partie nous présentons d’abord une synthèse de nos résultats, et nous exposons ensuite les perspectives que ce travail de recherche offre en termes de propositions en vue de l'élaboration d'ingénieries didactiques qui pourraient permettre la mise en place d’un travail coopératif entre professeurs et chercheursOur research focuses on the teacher's action and his interactions with students in the specific field of the study of digital in grade 2. The objective of this PhD dissertation is to analyze the teacher's action and his didactic practices in classes, and training practices in a CAPED in the Niger context. The first part of this PhD dissertation includes a presentation of the socio-economic and educational contexts in Niger. Then we examine the teaching practices in order to see if they allow students to take or not real responsibilities in relation to knowledge, and the appropriateness of collective design work sessions.In the second part, we present our theoretical tools, previous work related to our research objects, and the general problem tackled by our work. The third part is devoted to our methodological approach based on the study of textbook analyze, videos of classes and field observations. The fourth section discusses the mathematic resources used in the primary education in Niger and question the impact of these resources on the observed teachers' usual practices. The fifth and sixth sessions analyze empirical lessons in terms of topogenesis, and semiotic systems to study the knowledge involved in the didactic situations. In the seventh part, we propose an innovative in-service training based on the design of lessons in a collective CAPED. In conclusion, in an eighth part we first present a summary of our results, and then we present the perspectives that this research offers in terms of further developments of didactic engineering that could allow the implementation of a collaborative work between teachers and researchers
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Vestin, Albin, and Gustav Strandberg. "Evaluation of Target Tracking Using Multiple Sensors and Non-Causal Algorithms." Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-160020.
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Today, the main research field for the automotive industry is to find solutions for active safety. In order to perceive the surrounding environment, tracking nearby traffic objects plays an important role. Validation of the tracking performance is often done in staged traffic scenarios, where additional sensors, mounted on the vehicles, are used to obtain their true positions and velocities. The difficulty of evaluating the tracking performance complicates its development. An alternative approach studied in this thesis, is to record sequences and use non-causal algorithms, such as smoothing, instead of filtering to estimate the true target states. With this method, validation data for online, causal, target tracking algorithms can be obtained for all traffic scenarios without the need of extra sensors. We investigate how non-causal algorithms affects the target tracking performance using multiple sensors and dynamic models of different complexity. This is done to evaluate real-time methods against estimates obtained from non-causal filtering. Two different measurement units, a monocular camera and a LIDAR sensor, and two dynamic models are evaluated and compared using both causal and non-causal methods. The system is tested in two single object scenarios where ground truth is available and in three multi object scenarios without ground truth. Results from the two single object scenarios shows that tracking using only a monocular camera performs poorly since it is unable to measure the distance to objects. Here, a complementary LIDAR sensor improves the tracking performance significantly. The dynamic models are shown to have a small impact on the tracking performance, while the non-causal application gives a distinct improvement when tracking objects at large distances. Since the sequence can be reversed, the non-causal estimates are propagated from more certain states when the target is closer to the ego vehicle. For multiple object tracking, we find that correct associations between measurements and tracks are crucial for improving the tracking performance with non-causal algorithms.
Books on the topic "Action Observation System"
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Vet, R. J. GCOS observations programme for atmospheric constituents: Background, status and action plan. Geneva: Joint Planning Office, Global Climate Observing System, 1995.
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Jones, Alison L. Management of opioid poisoning. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0319.
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Opioids are ‘morphine like’ substances that have actions at specific opioid receptors (especially µ receptors) in the central nervous system (CNS). Tolerance of respiratory depression develops at a slower rate than analgesic tolerance, placing patients with a long history of opioid use at particular risk for respiratory depression. If chronic users abruptly stop taking opioids, they develop an acute withdrawal syndrome. Most opioid toxicity is the result of inadvertent overdosage during recreational use or in self-harm, but it can also be due to medication misuse and drug errors. It is characterized by three main clinical features (all may not be consistently present); depressed respiratory rate (the sine qua non of opioid poisoning) and respiratory volume, and reduced arterial oxygen desaturation, CNS depression, and small or pin-point pupils. Opioid-poisoned patients require early clinical assessment, appropriate administration of intravenous naloxone (competitive opioid antagonist) and meticulous respiratory supportive care, with close observation. Because of the longer half-life of opioids than naloxone, repeated doses may be needed for long-acting opioids or large doses of shorter acting opioids. If opioid antagonists are given to regular opioid users in excess, they can precipitate acute withdrawal symptoms. The need for ITU admission usually occurs as a result of a complication of the opioid toxicity.
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Norton, Bryan G. Toward Unity among Environmentalists. Oxford University Press, 1995. http://dx.doi.org/10.1093/oso/9780195093971.001.0001.
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Today, six out of ten Americans describe themselves as "active" environmentalists or as "sympathetic" to the movement's concerns. The movement, in turn, reflects this millions-strong support in its diversity, encompassing a wide spectrum of causes, groups, and sometimes conflicting special interests. For far-sighted activists and policy makers, the question is how this diversity affects the ability to achieve key goals in the battle against pollution, erosion, and out-of-control growth. This insightful book offers an overview of the movement -- its past as well as its present -- and issues the most persuasive call yet for a unified approach to solving environmental problems. Focusing on examples from resource use, pollution control, protection of species and habitats, and land use, the author shows how the dynamics of diversity have actually hindered environmentalists in the past, but also how a convergence of these interests around forward-looking policies can be effected, despite variance in value systems espoused. The book is thus not only an assessment of today's movement, but a blueprint for action that can help pull together many different concerns under a common banner. Anyone interested in environmental issues and active approaches to their solution will find the author's observations both astute and creative.
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Gur, Noam. Legal Directives and Practical Reasons. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780199659876.001.0001.
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This book investigates law’s interaction with practical reasons. What difference can legal requirements—be they traffic rules, tax laws, work safety regulations, or others—make to normative reasons relevant to our action? The book critically examines some of the existing answers to that question and puts forward an alternative account. At the outset, two competing positions are pitted against each other: first, the view taken by Joseph Raz, that when the law satisfies certain conditions that endow it with legitimate authority, it acquires pre-emptive force, namely it constitutes reasons for action that exclude and take the place of some other reasons; second, an antithetical position, according to which legal requirements cannot exclude otherwise applicable reasons, but can at most provide us with reasons that operate, and compete with opposing reasons, in terms of their weight. These positions are examined from several perspectives, such as justified disobedience cases, law’s conduct-guiding function, and the phenomenology associated with authority. It is found that, although each of the above positions offers insight into the relation between law and practical reasons, they both suffer from significant flaws. These observations lay the basis on which, in the final part of the book, an alternative position is put forward and defended. On this position, the existence and operation of a reasonably just and well-functioning legal system constitutes some reasons that are neither ordinary reasons for action nor pre-emptive ones, but rather reasons to adopt an (overridable) disposition that inclines its possessor towards compliance with the system’s requirements.
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Kováčik, Anton, and Eva Tvrdá, eds. Research in Animal Physiology: Proceedings of scientific papers. Slovak University of Agriculture in Nitra, Slovakia, 2020. http://dx.doi.org/10.15414/2020.9788055222349.
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Proceedings of scientific papers ranges across a breadth of research in animal physiology. The main chapters of this publication are “Animal Physiology - Health Status Observations; Biologically Active Compounds in Animal Physiology; Animal Toxicology”. Animal physiology is the scientific study of the life-supporting properties, functions and processes of animals or their parts. It focuses on how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. Therefore, the proper studying of animal physiology is crucial for understanding and evaluating underlying biological processes, behavioral states and animal response to different biological, social and environmental stimuli. As such, the principal aim of this proceedings of scientific papers was to gather original papers on research in the fields of animal physiology, animal nutrition, reproduction and toxicopathology. We hope the publication will serve as a forum for presenting contemporary knowledge on basic and applied research, thus making new findings, methods, and techniques easily accessible and applicable in practice.
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Copeland, Jeffrey P., Arild Landa, Kimberly Heinemeyer, Keith B. Aubry, Jiska van Dijk, Roel May, Jens Persson, John Squires, and Richard Yates. Social ethology of the wolverine. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198759805.003.0018.
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Social behaviour in solitary carnivores has long been an active area of investigation but for many species remains largely founded in conjecture compared to our understanding of sociality in group-living species. The social organization of the wolverine has, until now, received little attention beyond its portrayal as a typical mustelid social system. In this chapter the authors compile observations of social interactions from multiple wolverine field studies, which are integrated into an ecological framework. An ethological model for the wolverine is proposed that reveals an intricate social organization, which is driven by variable resource availability within extremely large territories and supports social behaviour that underpins offspring development.
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Wright, Dawn J., and Christian Harder, eds. GIS for Science, Volume 3: Maps for Saving the Planet. Esri Press, 2021. http://dx.doi.org/10.17128/9781589486713.
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GIS for Science: Maps for Saving the Planet, Volume 3, highlights real-world examples of scientists creating maps about saving life on Earth and preserving biodiversity. With Earth and the natural world at risk from various forces, geographic information system (GIS) mapping is essential for driving scientifically conscious decision-making about how to protect life on Earth. In volume 3 of GIS for Science, explore a collection of maps from scientists working to save the planet through documenting and protecting its biodiversity. In this volume, learn how GIS and data mapping are used in tandem with: global satellite observation forestry marine policy artificial intelligence conservation biology, and environmental education to help preserve and chronicle life on Earth. This volume also spotlights important global action initiatives incorporating conservation, including Half-Earth, 30 x 30, AI for Earth, the Blue Nature Alliance, and the Sustainable Development Solutions Network. The stories presented in this third volume are ideal for the professional scientist and conservationist and anyone interested in the intersection of technology and the conservation of nature. The book’s contributors include scientists who are applying geographic data gathered from the full spectrum of remote sensing and on-site technologies. The maps and data are brought to life using ArcGIS® software and other spatial data science tools that support research, collaboration, spatial analysis, and science communication across many locations and within diverse communities. The stories shared in this book and its companion website present inspirational ideas so that GIS users and scientists can work toward preserving biodiversity and saving planet Earth before time runs out.
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Chidester, Thomas R. Creating a Culture of Safety. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199366149.003.0008.
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Safety culture focuses on who is responsible in what ways for patient safety, ranging from individuals and teams performing critical duties on the front lines to the context within which work takes place, and high-level organizational priorities. Though it is a recent concept, it represents growth in the understanding of accident causation, and offers additional and potentially more broadly effective preventive actions. Key concepts include organizational commitment, operational interactions, formal and informal safety indicators, and safety behaviors and outcomes. Measurement can be accomplished through benchmarked surveys, case analysis, field observation, and examination of procedures, manuals, newsletters, brochures, and performance evaluation criteria for their safety focus. Intervening to improve safety culture requires assessing an organization’s current state, communicating safety and minimizing patient risk as a core value in a methodical and sustained manner, deploying and monitoring standardized procedures by workgroup, establishing feedback systems, and reporting progress in safety alongside economic progress.
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Dolman, Han. Biogeochemical Cycles and Climate. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198779308.001.0001.
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This book describes the interaction of the main biogeochemical cycles of the Earth and the physics of climate. It takes the perspective of Earth as an integrated system and provides examples of both changes in the current climate and those in the geological past. The first three chapters offer a general introduction to the context of the book, outlining the climate system as a complex interplay between biogeochemistry and physics and describing the tools available for understanding climate: observations and models. These chapters describe the basics of the system, the rates and magnitudes and the crucial aspects of biogeochemical cycles needed to understand their functioning. The second part of the book consists of four chapters that describe the physics required to understand the interaction of the climate with biogeochemistry and change. These chapters describe the physics of radiation, and that of the atmosphere, ocean circulation and thermodynamics. The interaction of aerosols with radiation and clouds is addressed in an additional chapter. The third part of the book deals with Earth’s (bio)geochemical cycles. These chapters focus on the stocks and fluxes of the main reservoirs of Earth’s biogeochemical cycles—atmosphere, land and ocean—and their role in the cycles of carbon, oxygen, nitrogen, iron, phosphorus, oxygen, sulphur and water, as well as their interactions with climate. The final two chapters describe possible mitigation and adaptation actions, in relation to recent climate agreements, but always with an emphasis on the biogeochemical aspects.
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Lheureux, Philippe, and Marc Van Nuffelen. Management of benzodiazepine poisoning. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199600830.003.0320.
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The wide use of benzodiazepines is associated with some inconveniences and are most frequently implicated in acute self-poisoning and accidental poisoning in children. Some of them are recognized as submission drugs, used to commit date rape or robbery. Prolonged use of a benzodiazepine leads to dependence, with a risk of developing a life-threatening withdrawal syndrome. Overdose has usually a good prognosis—most patients recover well with careful observation and prevention of complications, although care should be taken with elderly people, and patients with chronic obstructive pulmonary disease or liver dysfunction. Fast-acting agents and co-ingestion of other central nervous system depressants may be present greater risk. Early administration of activated charcoal in patients able to protect their airway is only needed if there are co-ingestants. Flumazenil may help confirm the diagnosis, improve alertness, and prevent the need for respiratory support in some patients, especially after accidental poisoning in children. Contraindications include patients on long-term treatment and/or dependent on benzodiazepines, or those who have simultaneously ingested proconvulsant or prodysrhythmic substances or at risk of increased intracranial pressure.
Book chapters on the topic "Action Observation System"
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Georgakopoulos, Dimitrios. "Information System Engineering Supporting Observation, Orientation, Decision, and Compliant Action." In Communications in Computer and Information Science, 14. Berlin, Heidelberg: Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-88479-8_2.
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Lamperti, Gianfranco, and Marina Zanella. "Complex Observations." In Diagnosis of Active Systems, 315–43. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0257-7_10.
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Lamperti, Gianfranco, and Marina Zanella. "Distributed Observations." In Diagnosis of Active Systems, 367–91. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0257-7_12.
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Lamperti, Gianfranco, and Marina Zanella. "Uncertain Observations." In Diagnosis of Active Systems, 267–313. Dordrecht: Springer Netherlands, 2003. http://dx.doi.org/10.1007/978-94-017-0257-7_9.
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Corrochano, Eduardo Bayro. "Rigid Motion Estimation Using Line Observations." In Geometric Computing for Perception Action Systems, 169–200. New York, NY: Springer New York, 2001. http://dx.doi.org/10.1007/978-1-4613-0177-6_8.
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Vaandrager, Frits, Bharat Garhewal, Jurriaan Rot, and Thorsten Wißmann. "A New Approach for Active Automata Learning Based on Apartness." In Tools and Algorithms for the Construction and Analysis of Systems, 223–43. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99524-9_12.
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AbstractWe present $$L^{\#}$$ L # , a new and simple approach to active automata learning. Instead of focusing on equivalence of observations, like the $$L^{*}$$ L ∗ algorithm and its descendants, $$L^{\#}$$ L # takes a different perspective: it tries to establish apartness, a constructive form of inequality. $$L^{\#}$$ L # does not require auxiliary notions such as observation tables or discrimination trees, but operates directly on tree-shaped automata. $$L^{\#}$$ L # has the same asymptotic query and symbol complexities as the best existing learning algorithms, but we show that adaptive distinguishing sequences can be naturally integrated to boost the performance of $$L^{\#}$$ L # in practice. Experiments with a prototype implementation, written in Rust, suggest that $$L^{\#}$$ L # is competitive with existing algorithms.
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Dold, J. W. "Observations on the Nature of Reaction Runaway in Reaction-Diffusion Systems." In Nonlinear Waves in Active Media, 210–17. Berlin, Heidelberg: Springer Berlin Heidelberg, 1989. http://dx.doi.org/10.1007/978-3-642-74789-2_28.
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Linsky, Jeffrey L. "Modelling the Coronae and Chromospheres of RS CVn Systems by the Analysis of Ultraviolet, X-Ray and Radio Observations." In Active Close Binaries, 747–59. Dordrecht: Springer Netherlands, 1990. http://dx.doi.org/10.1007/978-94-009-0679-2_53.
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Bernard, Tiziano, and Lucas Stephane. "An Exploratory Study of Pilot Observations, Decisions, and Actions During Traffic Pattern Approach Operations." In Advances in Intelligent Systems and Computing, 65–77. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-93885-1_7.
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Batsukh, Khulan. "Cold Atom Interferometry in Satellite Geodesy for Sustainable Environmental Management." In Civil and Environmental Engineering for the Sustainable Development Goals, 43–54. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-99593-5_4.
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AbstractOur Earth is a complex system. By monitoring the integrated geodetic-geodynamic processes, we can understand its sub-systems and geographical distribution of its resources. With the development of space techniques and artificial satellites, satellite geodesy era started, e.g., it became possible to observe a wide range of processes, occurring both on and below the Earth's surface. Such observations can be exploited not only in environmental activities, but also in societal activities like natural disasters monitoring. Thus, satellite geodesy can bring great benefits to “Climate action”, one of the 17 sustainable development goals of the United Nation: we can estimate the ice-sheet mass balance and study the impact of climate change by monitoring sea levels. This paper aims to investigate the possible implementation of cold atom sensors for future satellite gravity missions, which would improve our current knowledge of the Earth’s gravity field and contribute into the sustainable environmental management. Graphical Abstract
Conference papers on the topic "Action Observation System"
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Motoda, Tomohiro, Weiwei Wan, and Kensuke Harada. "Probabilistic Action/Observation Planning for Playing Yamakuzushi." In 2020 IEEE/SICE International Symposium on System Integration (SII). IEEE, 2020. http://dx.doi.org/10.1109/sii46433.2020.9025960.
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Hiramoto, Kazuhiko, Taichi Matsuoka, and Katsuaki Sunakoda. "High Performance Structural Vibration Control by a Preview of the Future Seismic Waveform Generated With a Wave Transmission Network and an AI-Based Estimation System." In ASME 2019 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/pvp2019-93184.
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Abstract We propose a new active vibration control strategy based on the future seismic waveform information obtained in remote observation sites. The waveform information in the remote site is transmitted by a waveform transmission network to the structure under control. The waveform transmission network is realized by interconnecting multiple controlled structures and observation sites. By using the future waveform information obtained through the network, we propose a control law realizing fairly higher control performance over the conventional structural control methodologies. A preview control law consisting of the state-feedback and feedforward control (preview action) is adopted. For the preview action, future values of the disturbance in some time interval are necessary. However, because the future value of the earthquake waveform is unknown, the preview action contributing the performance improvement is generally impossible. To get over this difficulty, an AI-based wave estimation system to estimate the future earthquake waveform is proposed. The wave estimation system is a multi-layered artificial neural network (ANN). Through a small scale simulation study with a recorded earthquake event in Japan, we show that the proposed control method achieves much higher control performance over the conventional LQ-based active control.
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Paramitha, P. E. "Digitalizing and Geo-Enabling Observation Cards to Improve Hazard Mitigation and Better Risk Assessment." In Indonesian Petroleum Association 44th Annual Convention and Exhibition. Indonesian Petroleum Association, 2021. http://dx.doi.org/10.29118/ipa21-o-208.
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Health, safety, and environment (HSE) play a vital role and sits at the highest pedestal in the oil and gas industry. It should therefore be the top priority in the oil and gas industry as this function enables a reduction in potential hazards, including injuries, fatalities, damage to facilities, and occupational safety. Field workers typically use observation cards to report the potential hazards or discrepancies discovered in the field. However, in some companies, reporting is still done manually by filling out the observation cards in handwritten paper form and then manually submitted to the HSE supervisor. The supervisor will receive all the forms, input the data into spreadsheets, analyze the data, then make decisions to mitigate the hazard(s). These workflows are certainly time-consuming and prone to errors. Therefore, this paper aims to simplify these workflows by enabling digital system of records and geospatial information on HSE observation. Geographic Information System (GIS) form-based mobile application that integrates object location, mobile phone camera, and textual information was developed. In this paper, a GIS digital-based form that connects spatial data with attribute data is presented. Field workers can use this form to report any potential hazards and acquired pictures of evidence using mobile devices. The report will be transmitted to the server database through a web service, being visualized and analyzed to alert the potential hazards for pro-active action. In addition, this GIS form-based mobile application can also be used in a web-based application for office workers. This application will reduce errors while filling the observation cards or adding the data to sheets manually. It also time-efficient since the submitted reports can be monitored in real-time, and the follow-up action can be executed sooner. This will provide easier accessibility and better experience of hazard reporting anytime and anywhere, improve hazard mitigation, and better risk assessment.
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Xu, Kai, Kaiming Xiao, Quanjun Yin, Yabing Zha, and Cheng Zhu. "Bridging the Gap between Observation and Decision Making: Goal Recognition and Flexible Resource Allocation in Dynamic Network Interdiction." In Twenty-Sixth International Joint Conference on Artificial Intelligence. California: International Joint Conferences on Artificial Intelligence Organization, 2017. http://dx.doi.org/10.24963/ijcai.2017/625.
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Goal recognition, which is the task of inferring an agent’s goals given some or all of the agent’s observed actions, is one of the important approaches in bridging the gap between the observation and decision making within an observe-orient-decide-act cycle. Unfortunately, few researches focus on how to improve the utilization of knowledge produced by a goal recognition system. In this work, we propose a Markov Decision Process-based goal recognition approach tailored to a dynamic shortest-path local network interdiction (DSPLNI) problem. We first introduce a novel DSPLNI model and its solvable dual form so as to incorporate real-time knowledge acquired from goal recognition system. Then a Markov Decision Process-based goal recognition model along with its dynamic Bayesian network representation and the applied goal inference method is proposed to identify the evader’s real goal within the DSPLNI context. Based on that, we further propose an efficient scalable technique in maintaining action utility map used in fast goal inference, and develop a flexible resource assignment mechanism in DSPLNI using knowledge from goal recognition system. Experimental results show the effectiveness and accuracy of our methods both in goal recognition and dynamic network interdiction.
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Shao, T. M., D. J. Xu, J. G. Luo, and C. J. Wu. "Impact Evaluation of Plasma Spray Coatings." In ITSC 1998, edited by Christian Coddet. ASM International, 1998. http://dx.doi.org/10.31399/asm.cp.itsc1998p0641.
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Abstract Impact performance of plasma spray coatings is usually evaluated by means of surface observation after impact action. As a matter of fact, the dynamic response characteristics of coatings in the course of impact action are also very important. In this paper, a method of response frequency spectrum analysis is developed for the impact evaluation of plasma spray coatings. An impact test machine, in which the impact load is generated by a pivot-rod-lever system, is specially designed, allowing both single impact test and repeated impact test. The frequency spectra of Cr2O3 ceramic coating and WC-Co17% alloy coating under single and repeated impact action are analyzed. The results show that there is an obvious relationship between the impact performance and the impact response frequency spectrum. Abrupt changes in the coating, such as appearance of surface cracks and surface damage, correspond the sudden changes of the response frequency spectrum.
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Haiyuan Wu, T. Fukumoto, Qian Chen, and M. Yachida. "Active face observation system." In Proceedings of 13th International Conference on Pattern Recognition. IEEE, 1996. http://dx.doi.org/10.1109/icpr.1996.546986.
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Lamperti, Gianfranco, Marina Zanella, and Xiangfu Zhao. "Diagnosis of Active Systems with Abstract Observations and Compiled Knowledge." In 18th International Conference on Principles of Knowledge Representation and Reasoning {KR-2021}. California: International Joint Conferences on Artificial Intelligence Organization, 2021. http://dx.doi.org/10.24963/kr.2021/42.
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An active system (AS) is a discrete-event system (DES) with asynchronous behavior, which is represented by a network of components that are modeled as communicating automata. When being operated, an AS performs a trajectory within its behavior space, while generating a sequence of observations, namely a temporal observation. The model of the AS and a temporal observation are the two key ingredients of the diagnosis task, which aims to find out possible faulty behavior via abductive reasoning. Among other knowledge, such reasoning requires knowing what is observable and what is not. This essential distinction constitutes the observability of the AS. In the literature, the observability of a DES boils down to qualifying each state transition either as observable or unobservable, which contrasts with the way humans observe reality, typically by mapping a collection of observations to a single, abstract perception. Moreover, the occurrence of single state transitions is not necessarily what we can observe or what we want to observe for diagnosis purposes. This paper presents an extended notion of observability, where each observation is associated with a behavioral scenario rather than a single state transition, where a scenario is defined as a regular language on state transitions. To speed up the online diagnosis engine, specific diagnosis-oriented knowledge is compiled offline. Eventually, the diagnosis technique based on abstract observability is extended to cope with temporal uncertainty.
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Gagne, Julien, Olivier Piccin, E´douard Laroche, and Jacques Gangloff. "A Heart Stabilization Device Exploiting Gyroscopic Actuation: Design and Control." In ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2010. http://dx.doi.org/10.1115/detc2010-28843.
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The heart motion is the main hindrance to the development of recent less invasive surgical techniques in the cardiac field. The problem can be partially solved by maintaining the intervention area with stabilizers but the remaining displacements are still important. We propose a device able to exert a torque on the stabilizer in order to compensate for heart action in real time. The system is based on gyroscopic actuation associated with acceleration sensing which allows to free from grounding constraints. In this paper we present first the system architecture and its mechanical model. We describe afterward the prototype design and the experimental setup. Then we detail the control strategy which includes a Kalman filter dedicated to the observation of both the state and the disturbance signals. Several control laws are compared based on disturbance compensation and static feedforward, taking into account gyroscopic actuation specificities. Finally these controls are tested in simulation on a more detailed model.
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Kooijman, J. D. G., A. L. Schwab, and Jason K. Moore. "Some Observations on Human Control of a Bicycle." In ASME 2009 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/detc2009-86959.
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The purpose of this study is to identify human control actions in normal bicycling. The task under study is the stabilization of the mostly unstable lateral motion of the bicycle-rider system. This is done by visual observation of the rider and measuring the vehicle motions. The observations show that very little upper-body lean occurs and that stabilization is done by steering control actions only. However, at very low forward speed a second control is introduced to the system: knee movement. Moreover, all control actions are performed at the pedaling frequency, whilst the amplitude of the steering motion increases rapidly with decreasing forward speed.
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Gil Tejeda, Jorge, and Lorena Olmos Pineda. "User Experiences Derived from Mass-Distribution Virtual Products are Integrated by the Spatio-Temporal Component." In 13th International Conference on Applied Human Factors and Ergonomics (AHFE 2022). AHFE International, 2022. http://dx.doi.org/10.54941/ahfe1001698.
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The mass-distribution virtual products affect in various dimensions to the users from the activation of the sensory mechanisms, anatomical responses until various cognitive processes. Through the observation of the inter-action processes made by a group of normal vision users in three mass-distribution virtual products with the assignment of a task was detected a constant in the processes of interaction: the spatio-temporal component. This component was present not only in the process of interaction with the virtual product but also in the process of interaction with the device’s work system. In turn the spatio-temporal component seems to have variations related in the activation of sensory mechanisms which depends on the characteristics of the object. The intention of these studies is to describe -with the use of networks- the spatio-temporal component during the interaction processes with the mass-distribution virtual products and to reflect on how this component affect the human behavior and user experiences.
Reports on the topic "Action Observation System"
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Granot, David, and Noel Michelle Holbrook. Role of Fructokinases in the Development and Function of the Vascular System. United States Department of Agriculture, January 2011. http://dx.doi.org/10.32747/2011.7592125.bard.
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Plant vascular tissues are superhighways whose development and function have profound implications for productivity, yield and stress response. Preliminary studies by the PI indicated that sugar metabolism mediated by fructokinases (FRKs) has a pronounced effect on the transport properties of the xylem. The goal of this research was to determine how the main fructokinase gene, FRK2, and the only plastidic fructokinase, FRK3, influence vascular development and physiology, emphasizing processes that occur at both the cellular and organismic level. We found that both genes are expressed in vascular tissues, but FRK3 is expressed primarily in vascular tissues of mature petioles. Vascular anatomy of plants with antisense suppression of FRK2 uncovered that FRK2 is necessary for xylem and phloem development, most likely due to its role in vascular cell-wall synthesis, and affects vascular development all over the plant. As a result, suppression of FRK2 reduced hydraulic conductivity of roots, stem and leaves and restricted sugar phloem transport. Vascular anatomy of plants with RNAi suppression of FRK3 uncovered that FRK3 is required for vascular development in mature petiole but its role is partially complemented by FRK2. Suppression of FRK3 combined with partial suppression of FRK2 had effects completely different from that of FRK2 suppression, resulting in wilting of mature leaves rather than young leaves of FRK2 suppressed plants, and decreased export of photoassimilates. This primary effect of FRK2 suppression on mature petioles had a secondary effect, reducing the hydraulic conductivity in roots and stem. The very fact that a plastidic fructokinase plays a role in vascular development is quite surprising and we are still seeking to uncover its metabolic mode-of-action. Yet, it is clear that these two fructokinases have different roles in the coordination between photosynthetic capacity and vascular development. We have started analyzing the role of the last third FRK, FRK1, and discovered that it is also expressed exclusively in vascular tissues. It appears therefore, that all FRKs studied here are involved in vascular development. An interesting unexpected outcome of this study was the connection of FRK2 with hormonal regulation of vascular development, most likely auxin. This observation together with the yet to be solved questions on the exact roles of FRK3 are the subjects of our current efforts.
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Gordon, Dalia, Ke Dong, and Michael Gurevitz. Unexpected Specificity of a Sea Anemone Small Toxin for Insect Na-channels and its Synergic Effects with Various Insecticidal Ligands: A New Model to Mimic. United States Department of Agriculture, November 2010. http://dx.doi.org/10.32747/2010.7697114.bard.
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Motivated by the high risks to the environment and human health imposed by the current overuse of chemical insecticides we offer an alternative approach for the design of highly active insect-selective compounds that will be based on the ability of natural toxins to differentiate between insect and mammalian targets. We wish to unravel the interacting surfaces of insect selective toxins with their receptor sites on voltage-gated sodium channels. In this proposal we put forward two recent observations that may expedite the development of a new generation of insect killers that mimic the highly selective insecticidal toxins: (i) A small (27aa) highly insecticidal sea anemone toxin, Av3, whose toxicity to mammals is negligible; (ii) The prominent positive cooperativity between distinct channel ligands, such as the strong enhancement of pyrethroids effects by anti-insect selective scorpion depressant toxins. We possess a repertoire of insecticidal toxins and sodium channel subtypes all available in recombinant form for mutagenesis followed by analysis of various pharmacological, electrophysiological, and structural methods. Our recent success to express Av3 provides for the first time a selective toxin for receptor site-3 on insect sodium channels. In parallel, our recent success to determine the structures and bioactive surfaces of insecticidal site-3 and site-4 toxins establishes a suitable system for elucidation of toxin-receptor interacting faces. This is corroborated by our recent identification of channel residues involved with these two receptor sites. Our specific aims in this proposal are to (i) Determine the bioactive surface of Av3 toward insect Na-channels; (ii) Identify channel residues involved in binding or activity of the insecticidal toxins Av3 and LqhaIT, which differ substantially in their potency on mammals; (iii) Illuminate channel residues involved in recognition by the anti-insect depressant toxins; (iv) Determine the face of interaction of both site-3 (Av3) and site-4 (LqhIT2) toxins with insect sodium channels using thermodynamic mutant cycle analysis; and, (v) Examine whether Av3, LqhIT2, pyrethroids, and indoxacarb (belongs to a new generation of insecticides), enhance allosterically the action of one another on the fruit fly and cockroach paraNa-channels and on their kdr and super-kdr mutants. This research establishes the grounds for rational design of novel anti-insect peptidomimetics with minimal impact on human health, and offers a new approach in insect pest control, whereby a combination of allosterically interacting compounds increases insecticidal action and reduces risks of resistance buildup.
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Phillips, Donald A., Yitzhak Spiegel, and Howard Ferris. Optimizing nematode management by defining natural chemical bases of behavior. United States Department of Agriculture, November 2006. http://dx.doi.org/10.32747/2006.7587234.bard.
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This project was based on the hypothesis that nematodes interacting with plants as either parasites or beneficial saprophytes are attracted to their host by natural products. This concept was supported by numerous observations that parasitic nematodes are attracted to root exudates. Our overall goal was to identify nematode sensory compounds from root exudates and to use that information for reducing nematicide applications. We applied skills of the investigators to achieve three specific objectives: 1) Identify nematode behavioral cues (e.g., attractants or repellents) in root exudates; 2) Identify new natural nematicidal compounds; and 3) Combine a natural attractant and a nematicide into a nematode trap. Because saprophytic nematodes benefit plants by mineralizing organic matter, we sought compounds attractive primarily to parasitic nematodes. The project was constructed on several complementary foundations. First, data from Dr. Spiegel’s lab showed that under aseptic conditions Ditylenchus dipsaci, a parasite on onion, is attracted to certain fractions of onion root exudates. Second, PI Phillips had a sizeable collection of natural plant products he had identified from previous work on Rhizobium-legume interactions, which could be tested “off the shelf”. Third, Dr. Ferris had access to aseptic and natural populations of various saprophytic and parasitic nematodes. The project focused on five nematode species: D.dipsaci, Heterodera avenae, and Tylenchulussemipenetransat ARO, and Meloidogyne javanicand Caenorhabditis elegans at UCD. Ten pure plant compounds, mostly flavonoids, were tested on the various nematode species using six different assay systems. Results obtained with assorted test systems and by various scientists in the same test systems were essentially irreproducible. Many convincing, Many convincing, i.e. statistically significant, results in one system or with one investigator could not be repeated with other assays or different people. A recent report from others found that these compounds, plus another 30, were inactive as attractants in three additional parasitic nematode species (Wuyts et al. Nematology 8:89- 101, 2006). Assays designed to test the hypothesis that several compounds together are required to attract nematodes have thus far failed to find a reproducibly active combination. In contrast to results using pure plant compounds, complex unfractionated exudates from aseptic onion root reproducibly attracted D. dipsaci in both the ARO and UCD labs. Onion root exudate collection, separation into HPLC fractions, assays using D. dipsaci and MS-MS experiments proceeded collaboratively between ARO and UCD without any definitive identification of an active compound. The final active fraction contained two major molecules and traces of several other compounds. In the end, analytical studies were limited by the amount of onion root exudate and the complexity of the purification process. These tests showed that aseptic plant roots release attractant molecules, but whether nematodes influence that release, as insects trigger release of attractants from plants, is unknown. Related experiments showed that the saprophyte C. elegans stimulates its prey, Pseudomonas bacteria, to increase production of 2, 4-diacetylphloroglucinol (DAPG) a compound that promotes amino acid exudation by plant roots. It is thus possible that saprophytic nematodes are attracted primarily to their bacterial or fungal prey and secondarily to effects of those microorganisms on root exudation. These observations offer promising avenues for understanding root-zone interactions, but no direct routes to controlling nematodes in agriculture were evident. Extracts from two plant sources, Chrysanthemum coronarium and Sequoia sempervirens, showed nematicidal activity at ARO and UCD, respectively. Attempts to purify an active compound from S. sempervirens failed, but preliminary results from C. coronarium are judged to form a potential basis for further work at ARO. These results highlight the problems of studying complex movement patterns in sentient organisms like nematodes and the issues associated with natural product isolation from complex mixtures. Those two difficulties combined with complications now associated with obtaining US visas, slowed and ultimately limited progress on this project. As a result, US investigators expended only 65% of the $207,400 originally planned for this project. The Israeli side of the project advanced more directly toward its scientific goals and lists its expenditures in the customary financial report.
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Czajka, Leo, Florence Kondylis, Bassirou Sarr, and Mattea Stein. Data Management at the Senegalese Tax Authority: Insights from a Long-term Research Collaboration. Institute of Development Studies, December 2022. http://dx.doi.org/10.19088/ictd.2022.020.
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As they increasingly adopt digital infrastructure, public administrations worldwide are increasingly collecting, generating and managing data. Empirical researchers are, at the same time, collaborating more and more with administrations, accessing vast amounts of data, and setting new research agendas. These collaborations have taken place in low-income countries in particular, where administrative data can be a valuable substitute for scarce survey data. However, the transition to a full-fledged digital administration can be a long and difficult process, sharply contrasting the common leap-frog narrative. Based on observations made during a five-year research collaboration with the Senegalese tax administration, this qualitative case study discusses the main data management challenges the tax administration faces. Much progress has recently been made with the modernisation of the administration’s digital capacity ,and adoption of e-filling and e-payment systems. However, there remains substantial scope for the administration to enhance data management and improve its efficiency in performing basic tasks, such as the identification of active taxpayers or the detection of various forms of non-compliance. In particular, there needs to be sustained investment in human resources specifically trained in data analysis. Recently progress has been made through creating – in collaboration with the researchers – a ‘datalab’ that now works to improve processes to collect, clean, merge and use data to improve revenue mobilisation.
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Schaffer, Arthur, Jack Preiss, Marina Petreikov, and Ilan Levin. Increasing Starch Accumulation via Genetic Modification of the ADP-glucose Pyrophosphorylase. United States Department of Agriculture, October 2009. http://dx.doi.org/10.32747/2009.7591740.bard.
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The overall objective of the research project was to utilize biochemical insights together with both classical and molecular genetic strategies to improve tomato starch accumulation. The proposal was based on the observation that the transient starch accumulation in the immature fruit serves as a reservoir for carbohydrate and soluble sugar content in the mature fruit, thereby impacting on fruit quality. The general objectives were to optimize AGPase function and activity in developing fruit in order to increase its transient starch levels. The specific research objectives were to: a) perform directed molecular evolution of the limiting enzyme of starch synthesis, AGPase, focussing on the interaction of its regulatory and catalytic subunits; b) determine the mode of action of the recently identified allelic variant for the regulatory subunit in tomato fruit that leads to increased AGPase activity and hence starch content. During the course of the research project major advances were made in understanding the interaction of the small and large subunits of AGPase, in particular the regulatory roles of the different large subunits, in determining starch synthesis. The research was performed using various experimental systems, including bacteria and Arabidopsis, potato and tomato, allowing for broad and meaningful conclusions to be drawn. A novel discovery was that one of the large subunits of tomato AGPase is functional as a monomer. A dozen publications describing the research were published in leading biochemical and horticultural journals. The research results clearly indicated that increasing AGPase activity temporally in the developing fruit increase the starch reservoir and, subsequently, the fruit sugar content. This was shown by a comparison of the carbohydrate balance in near-isogenic tomato lines differing in a gene encoding for the fruit-specific large subunit (LS1). The research also revealed that the increase in AGPase activity is due to a temporal extension of LS1 gene expression in the developing fruit which in turn stabilizes the limiting heterotetrameric enzyme, leading to sustained starch synthesis. This genetic variation can successfully be utilized in the breeding of high quality tomatoes.
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Phillips, Donald, and Yoram Kapulnik. Using Flavonoids to Control in vitro Development of Vesicular Arbuscular Mycorrhizal Fungi. United States Department of Agriculture, January 1995. http://dx.doi.org/10.32747/1995.7613012.bard.
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Vesicular-arbuscular mycorrhizal (VAM) fungi and other beneficial rhizosphere microorganisms, such as Rhizobium bacteria, must locate and infect a host plant before either symbiont profits. Although benefits of the VAM association for increased phosphorous uptake have been widely documented, attempts to improve the fungus and to produce agronomically useful amounts of inoculum have failed due to a lack of in vitro production methods. This project was designed to extend our prior observation that the alfalfa flavonoid quercetin promoted spore germination and hyphal growth of VAM fungi in the absence of a host plant. On the Israeli side of the project, a detailed examination of changes in flavonoids and flavonoid-biosynthetic enzymes during the early stages of VAM development in alfalfa found that VAM fungi elicited and then suppressed transcription of a plant gene coding for chalcone isomerase, which normally is associated with pathogenic infections. US workers collaborated in the identification of flavonoid compounds that appeared during VAM development. On the US side, an in vitro system for testing the effects of plant compounds on fungal spore germination and hyphal growth was developed for use, and intensive analyses of natural products released from alfalfa seedlings grown in the presence and absence of microorganisms were conducted. Two betaines, trigonelline and stachydrine, were identified as being released from alfalfa seeds in much higher concentrations than flavonoids, and these compounds functioned as transcriptional signals to another alfalfa microsymbiont, Rhizobium meliloti. However, these betaines had no effect on VAM spore germination or hyphal growth i vitro. Experiments showed that symbiotic bacteria elicited exudation of the isoflavonoids medicarpin and coumestrol from legume roots, but neither compound promoted growth or germination of VAM fungi in vitro. Attempts to look directly in alfalfa rhizosphere soil for microbiologically active plant products measured a gradient of nod-gene-inducing activity in R. meliloti, but no novel compounds were identified for testing in the VAM fungal system in vitro. Israeli field experiments on agricultural applications of VAM were very successful and developed methods for using VAM to overcome stunting in peanuts and garlic grown in Israel. In addition, deleterious effects of soil solarization on growth of onion, carrot and wheat were linked to effects on VAM fungi. A collaborative combination of basic and applied approaches toward enhancing the agronomic benefits of VAM asociations produced new knowledge on symbiotic biology and successful methods for using VAM inocula under field conditions