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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

The Accuracy of Time-to-Contact Estimation in the Prediction Motion Paradigm

Pei, Jiantao, n/a January 2002 (has links)
This thesis is concerned with the accuracy of our estimation of time to make contact with an approaching object as measured by the “Prediction Motion” (PM) technique. The PM task has commonly been used to measure the ability to judge time to contact (TTC). In a PM task, the observer's view of the target is occluded for some period leading up to the moment of impact. The length of the occlusion period is varied and the observer signals the moment of impact by pressing a response key. The interval separating the moment of occlusion and the response is interpreted as the observer's estimate of TTC made at the moment of occlusion. This technique commonly produces large variability and systematic underestimation. The possibility that this reflects genuine perceptual errors has been discounted by most writers, since this seems inconsistent with the accuracy of interceptive actions in real life. Instead, the poor performance in the PM task has been attributed to problems with the PM technique. Several hypotheses have been proposed to explain the poor PM performance. The motion extrapolation hypothesis asserts that some form of mental representation of the occluded part of the trajectory is used to time the PM response; the errors in PM performance are attributed to errors in reconstructing the target motion. The clocking hypothesis assumes that the TTC is accurately perceived at the moment of occlusion and that errors arise in delaying the response for the required period. The fear-of-collision hypothesis proposes that the underestimation seen in the PM tasks reflects a precautionary tendency to anticipate the estimated moment of contact. This thesis explores the causes of the errors in PM measurements. Experiments 1 and 2 assessed the PM performance using a range of motion scenarios involving various patterns of movement of the target, the observer, or both. The possible contribution of clocking errors to the PM performance was assessed by a novel procedure designed to measure errors in the wait-and-respond component of the PM procedure. In both experiments, this procedure yielded a pattern of systematic underestimation and high variability similar to that in the TTC estimation task. Experiment 1 found a small effect of motion scenario on TTC estimation. However, this was not evident in Experiment 2. The collision event simulated in Experiment 2 did not involve a solid collision. The target was simply a rectangular frame marked on a tunnel wall. At the moment of “contact”, the observers passed “through” the target without collision. However, there was still systematic underestimation of TTC and there was little difference between the estimates obtained in Experiments 1 and 2. Overall, the results of Experiments 1 and 2 were seen as inconsistent with either the motion extrapolation hypothesis or the fear-of-collision hypothesis. It was concluded that observers extracted an estimate of the TTC based on optic TTC information at a point prior to the moment of collision, and used a timing process to count down to the moment of response. The PM errors were attributed to failure in this timing process. The results of these experiments were seen as implying an accurate perception of TTC. It was considered possible that in Experiments 1 and 2 observers based their TTC judgements on either the retinal size or the expansion rate of the target rather than TTC. Experiments 3 and 4 therefore investigated estimation of TTC using a range of simulated target velocities and sizes. TTC estimates were unaffected by the resulting variation in expansion rate and size, indicating that TTC, rather than retinal size or image expansion rate per se, was used to time the observers' response. The accurate TTC estimation found in Experiments 1-4 indicates that the TTC processing is very robust across a range of stimulus conditions. Experiment 5 further explored this robustness by requiring estimation of TTC with an approaching target which rotated in the frontoparallel plane. It was shown that moderate but not fast rates of target rotation induced an overestimation of TTC. However, observers were able to discriminate between TTCs for all rates of rotation. This shows that the extraction of TTC information is sensitive to perturbation of the local motion of the target border, but it implies that, in spite of these perturbations, the mechanism is flexible enough to pick up the optic TTC information provided by the looming of the retinal motion envelop of the rotating stimulus.
62

Pour une esthétique in-formationnelle. La création artistique comme anticipation des usages sociaux des TIC

Emmanuel, Mahé 04 November 2004 (has links) (PDF)
Si, dans notre tentative pour penser les usages futurs des technologies de l'information et de la communication, nous sommes sans doute inévitablement enfermés dans les limites des usages actuels, peut-être les artistes qui mobilisent ces technologies peuvent-ils, qu'ils en aient ou non conscience, nous donner à voir des logiques et des pratiques qui permettent d'imaginer quelques éléments de ce futur. Ceci, bien entendu suppose que les artistes soient capables d'anticipations dans le domaine de l'innovation technologique. Pour explorer cette hypothèse, nous avons volontairement décidé d'analyser des productions artistiques pour tenter de comprendre comment les « usages artistiques » se forment dans le cours de l'élaboration et de la réalisation d'un projet, mais également la façon dont ces oeuvres, qualifiées de « tekhnê-logiques », inventent ou mettent en scène de nouveaux usages (imaginés ou réels) liées à la communication contemporaine. Les Technologies de l'Information et de la communication, dans ce contexte, apparaissent comme des outils de production et non pas seulement des outils de diffusion ou de transmission. Les artistes ne se limitent par à travailler avec les TIC mais aussi à travailler sur elles, en leur attribuant de nouvelles formes esthétiques, organisationnelles, symboliques, en créant de nouveaux dispositifs communicationnels. En parallèle à ces analyses de pratiques artistiques multimedia, une analyse approfondie des collaborations entre un centre de R-D (France Télécom R&D) et des artistes a été menée pendant trois années (de 2001 à 2004) pour comprendre comment les coopérations s'établissent, aboutissant à des innovations dans le domaine des télécommunications. Ces analyses ne valent pas tant par les objets qu'elles traitent et les résultats auxquelles elles aboutissent que par la façon dont elles ont été traitées, c'est-à-dire par l'élaboration progressive d'une approche fondée sur l'hypothèse d'une analyse en termes d'esthétique « in-formationnelle ». Cette approche permet de questionner les notions d'usages, d'anticipation et d'innovation à travers les notions de forme et d'in-formation, c'est-à-dire en questionnant leurs différentes régimes de visibilité, et en élaborant l'hypothèse que les TIC se présentent aujourd'hui sous la forme de « Gaz media » (ou « Khaos media »). Le projet de cette recherche est de considérer que l'Esthétique doit être ré-investie, davantage qu'elle ne l'est encore, par les Sciences de l'Information et de la Communication, non seulement comme objet, mais surtout comme théorie des formes et des processus.
63

La coarticulation en français et en chinois: étude expérimentale et modélisation

Ma, Liang 28 April 2008 (has links) (PDF)
Comme d'autres mouvements humains, les gestes de la parole sont vraisemblablement planifiés selon des stratégies optimales. Cependant, il est probable que la planification de ces gestes soit aussi contrainte par des critères de nature linguistique. De telles contraintes pourraient porter notamment sur la structure phonologique et la longueur des séquences prises en compte dans la planification. Le but de cette thèse a été d'approfondir cette hypothèse à partir de l'analyse de données expérimentales et de simulations avec un modèle. <br />Pour cela, la coarticulation anticipante a été étudiée expérimentalement dans des séquences Voyelle1-Consonne-Voyelle2 (V1CV2) pour deux langues différentes, le français et le chinois, à partir de données articulatoires et acoustiques. Les résultats de nos analyses montrent que les locuteurs français et chinois ont adopté des stratégies de planification différentes : en français l'anticipation s'étend au delà des frontières de la syllabe CV, alors qu'en chinois ce n'est pas le cas. Pour valider cette interprétation sur le rôle de la syllabe, un modèle de contrôle moteur a été élaboré exploitant une stratégie de planification qui minimise un critère combinant effort articulatoire et contraintes perceptives, et il a été testé sur un modèle biomécanique de la langue. Différentes hypothèses sur la structure phonologique de la séquence planifiée ainsi que sur l'exécution du mouvement ont été testées dans ce cadre. Les simulations ont été comparées aux données. Nos résultats soutiennent l'hypothèse selon laquelle les influences de la syllabe seraient plus fortes en mandarin qu'en français.
64

Les modalités du contrôle cognitif en situation dynamique : anticipation et gestion des dérives. Le cas de l'anesthésie

Neyns, Valérie 24 February 2011 (has links) (PDF)
L'objectif poursuivi à travers cette thèse est de comprendre comment l'anesthésiste garde le contrôle de la situation. Trois études seront présentées. La première d'entre elles permet de mettre en évidence à la fois les mécanismes de détection et de récupération des dérives en situation réelle. La seconde étude permet de comprendre à la fois les éléments défaillants dans l'anticipation des incidents et les modes de récupération mis en oeuvre par les anesthésistes. La dernière étude apporte des précisions sur les différences selon l'implication de l'anesthésiste dans le processus, l'impact de la prévisibilité des cas et de la fréquence d'apparition d'un risque. Les principaux résultats obtenus montrent que (1) La gestion des risques est partagée entre les différents membres de l'équipe. (2) La gestion temporelle apparaît être un élément essentiel dans la maîtrise de la situation tant au niveau de la synchronisation de l'activité de l'anesthésiste qu'au niveau de l'anticipation et de sa mise en application. En effet, l'anesthésiste travaille souvent sur un mode anticipatif afin de prévenir d'éventuelles dérives mais, il ne peut pas tout anticiper. La planification effectuée est alors une planification à court terme et de nombreux ajustements sont nécessaires pour permettre à l'anesthésiste de garder le contrôle. (3) L'étude de la récupération des dérives montre que celle-ci est assurée par l'utilisation de protocoles et de guidelines recommandés par la spécialité mais également une certaine " allostasie du risque ". (4) L'impact de l'anticipation sur la gestion des risques est controversé car elle peut permettre à la fois une meilleure gestion mais également induire l'anesthésiste en erreur lorsque celui-ci estime que l'anticipation effectuée a normalement permis d'éviter le problème. Enfin, (5) les différences observées dans l'organisation du processus montre que les anesthésistes gèrent soit le processus par prévention soit par gestion en temps réel. Ces résultats sont discutés en regard de l'intérêt d'étudier les écarts à la norme, de la complémentarité des méthodes utilisées et de l'importance de la gestion positive des dérives en insistant sur les mécanismes de maintien de la sécurité mis en place par l'opérateur humain.
65

Approche dynamique de l'intelligence économique en entreprise : apports d'un modèle psychologique des compétences : Contribution à l‘élaboration de programmes d‘actions de la CCI de Rennes

Dufour, Fanny 17 September 2010 (has links) (PDF)
Notre travail de recherche a pour ambition de contribuer à l‘optimisation des pratiques d‘accompagnement individuel et collectif des entreprises de la Chambre de Commerce et d‘Industrie (CCI) de Rennes. Notre démarche scientifique propose une approche renouvelée du couple « Innovation et Intelligence Economique », levier de la dynamique d‘adaptation des entreprises. Nous situons nos travaux à partir des acquis et des enseignements historiques de la CCI de Rennes en matière de stimulation des entreprises à « agir par anticipation ». Notre enjeu étant de décrire les processus sous-jacents aux activités d‘anticipation et d‘adaptation des entreprises, dans un écosystème en mutation, nous proposons en premier lieu une lecture des méthodologies et modèles de l‘intelligence économique par le prisme de ces activités. Nous recourrons ensuite à un modèle psychologique de description et d‘analyse des compétences afin de modéliser les dynamiques d‘adaptation des entreprises, et d‘y situer les activités d‘intelligence économique, d‘innovation et d‘organisation humaine agile. Un recueil de données terrain, auprès d‘experts et de dirigeants d‘entreprises, permet la construction de référentiels de compétences collectives opérationnelles en intelligence économique. Un second recueil de données auprès d‘un collectif « en mouvement» est l‘occasion de proposer des indicateurs de mise en oeuvre d‘une organisation humaine agile favorisant la dynamique d‘adaptation. Pour finir, des outils applicatifs sont mis à disposition de la CCI de Rennes et aux cadres et dirigeants d‘entreprises, leur permettant de piloter leur dynamique d‘adaptation
66

Contribution théorique à l'étude des motivations multiples/Theoretical contribution to the study of multiple motivations

Anselme, Patrick 18 October 2007 (has links)
Behaviour is usually assumed to depend on the reach of a critical intensitytermed reactivity thresholdby its motivation. This view represents a simple, predictive theoretical framework in ethology and psychology. However, it is here argued that only the influence of an isolated motivation on behaviour can be explained that way; that such a view fails to account for behaviour when several motivations are jointly activated. Upon analysis, the 'classical' theory of behaviour proves to be under-specified and thus leads to three conceptual problems that make it logically inconsistent for the study of multiple motivations. A revision of the 'classical' théory, called Anticipatory Dynamics Model (ADM), is then developed in order to bring a theoretical solution to these conceptual problems. The ADM hypothesizes that an organisms motivational interactions are due to the limitation of the organisms attentional resources. Several experiments are designed to test major predictions of the ADM. Tout comportement est censé dépendre du fait que sa motivation atteint une valeur critique d'intensité appelée seuil de réactivité. Cette approche constitue un cadre théorique simple et prédictif aussi bien en éthologie qu'en psychologie. Cependant, je tente de montrer que seule l'influence d'une motivation isolée sur le comportement peut être expliquée de cette façon ; que cette approche cesse d'être applicable lorsque plusieurs motivations sont activées simultanément. Après analyse, cette théorie 'classique' s'avère sous-spécifiée et conduit à trois problèmes conceptuels qui la rendent logiquement inconsistante pour l'étude des motivations multiples. Une révision de cette théorie 'classique', appelée Modèle de Dynamique Anticipatoire (MDA), est ainsi développée en vue d'apporter une solution théorique à ces problèmes conceptuels. Le MDA fait l'hypothèse que les interactions motivationnelles d'un organisme sont causées par la limitation de ses ressources attentionnelles. Plusieurs expériences ont été imaginées pour tester des prédictions importantes du MDA.
67

The Research of Anticipation to Purchase Likelihood-A Case of Watsons's Promotion Activities.

Jiang, Yi 13 January 2012 (has links)
In recent years, as the economy in Taiwan grown strongly, the lifestyles changed into a modern pattern, which had placed the traditional society. In the new, fashion, and modern lifestyles, here comes a new type of consumption. In order to adapt the new environment, marketers have developed many kinds of marketing skills to promote the services or products they provide. Therefore, sales promotions have been significantly over the years. Sales promotions are short-term incentives to encourage customers to make a purchase. As consumers are exposed to the sales promotions, their perceptions of the sales promotions play an important role in leading consumers to make purchase decisions. In sum, the purpose of this research is to discuss the relation between sales promotions and the purchase likelihood; we also try to explain how the cognition from consumers impacts their purchase likelihood. Thus, the following are our purpose: 1. To evaluate whether the sales promotions from Watsons can affect the quality perception of consumers. 2. To understand the relation between the internal reference price and perceived transaction value. 3. To analyze the relation between perceived acquisition value and purchase likelihood 4. To explore how the purchase likelihood change when the anticipation of sales promotions fail. 5. Discuss the differences of cognition toward sales promotions in Watson within genders. In this research, I administered a questionnaire to explore the data from 223 participants. The findings are as followed: 1. The sales promotions from Watsons have significant impacts on quality perception of consumers. 2. Consumers¡¦ internal reference price has significant impacts on perceived transaction value. 3. Perceived acquisition value have significant impacts on purchase likelihood 4. The failure of anticipation toward the sales promotion will decrease consumers¡¦ purchase likelihood. 5. There¡¦s no difference of cognition toward sales promotions within genders.
68

An Empirical Study on Anticipation of Organizational Change and Job Insecurity and The Employee¡¦s Working Reaction¡V Example in Kaohsiung Area local hospital

Tseng, Chih-Hung 19 December 2003 (has links)
There is a trend that the phenomenon of inequality is behaved in the market of medical treatment after the exercise of public health insurance. The large-scale hospitals incrementally enlarge to squeeze the survival condition of small and medium hospitals under the situation that supreme will survive to enhance competitive advantage. The competition is fierce between local hospitals to be based on the inequality of survival condition and unreasonable payment system of public health insurance. The research of Tong-Liang Chiang and Ming-San Huang (2000) indicates following phenomenon: the 77% of manager of local hospitals think that the competition is obviously increased between local hospitals after the exercise of public health insurance. The job insecurity of employees is generated by the expecting psychological condition that is derived from change in the organization under the impact of current environment and pressure of survival. What is the response of work influenced by job insecurity? What is the management lesson of hospital brought in the competition of hospitals? I hope to find the real response of employees under situation that feeling of job insecurity is derived by the expecting psychological condition of change in the organization. What is the relationship by the addition of individual personality? There are main findings in the research through the analysis of evidence: 1. Job insecurity is evident positive relevant to variation on work scenario, variation on structure of human resource, variation on management pattern of organization and variation on opportunity of employment that is belongs to the expecting factor of change in the organization. The higher score of variation on work scenario, variation on structure of human resource, variation on management pattern of organization and variation on opportunity of employment, the much easier generation of job insecurity. 2. For the job insecurity, the deviation of explanation on job insecurity is evidently related with the model of expecting factor of change in the organization. And the variation on work scenario and variation on opportunity of employment are evidently influenced by job security. 3. Job insecurity is partial evidently related with the immediate effect that is derived between the expecting change in organization and organizational commitment, leave attitude, work satisfaction, service attitude. 4. The employees that have personality of self-control are evidently interfered by the job insecurity that is derived from variation on work scenario, variation on opportunity of employment, variation on management pattern of organization and variation on work character. The employees that have personality of extraversion are evidently interfered by the job insecurity that is derived from variation on structure of human resource and variation on work character.
69

The experience of . . . suspense: understanding the construct, its antecedents, and its consequences in consumption and acquisition contexts

Guidry, Julie Anna 17 February 2005 (has links)
“Will my flight be cancelled?” “Will I win the eBay auction?” These consumption and product acquisition situations would trigger the experience of . . . suspense. Suspense is defined as the overall anticipatory arousal associated with the hope and/or fear felt by a consumer assessing the likelihood of occurrence of an important and imminent consumption or acquisition event. If one views a potential outcome as causing pleasure (an approach appraisal), hope will be felt, while if one views a potential outcome as causing pain (an avoidance appraisal), fear will be felt. Other variables expected to indirectly impact suspense are frequency of probability change, degree of probability change and anticipation time. The conceptual model in this dissertation also proposes that people have an attitude toward the anticipation period and identifies four resolution emotions, satisfaction, disappointment, relief, and anguish, which may occur once the outcome is known. Further, attitude toward anticipation period and the resolution emotions are expected to affect attitude toward overall experience. Three studies were conducted. The objective of Studies 1 and 2 was to develop scales yielding reliable scores of hope, fear, and suspense. Fifty words related to hope, fear, and suspense were generated. In Study 1, 553 participants rated the words on the evaluative and activity dimensions using 18 semantic differential scale items. O-technique factor analysis was used to analyze the data in Study 1. In Study 2, 354 participants read one of three suspenseful stories, then indicated their hope, fear, and suspense. Exploratory and confirmatory factor analyses were used in Study 2. Study 3 consisted of an experiment in which 241 participants read a suspenseful house-buying scenario, then indicated their hope, fear, and suspense. Structural equation modeling was used to analyze the data in Study 3. Results supported the conceptualization of suspense: both hope and fear had a positive effect on suspense. Additionally, approach appraisal had a positive effect on hope, and avoidance appraisal had a positive effect on fear. The moderating effect of frequency of probability change was not supported. However, frequency of probability change did have a positive effect on both hope and fear.
70

Affective responses in cocaine-experienced rats reveal cue-induced drug craving and cocaine reward magnitude

Maier, Esther Yvonne 15 January 2013 (has links)
The development and persistence of cocaine dependence are greatly influenced by emotional affect and cocaine associative learning. Cocaine is known to enhance nucleus accumbens (NAcc) dopamine, serve as a positive reinforcer and produce negative effects, such as anxiety that may influence cocaine intake behavior. In the first study, I investigated the effects of the anxiolytic, diazepam on NAcc dopamine levels and cocaine self-administration behavior. These are two factors associated with cocaine rewarding effects. Diazepam has no effect on NAcc dopamine, but affects cocaine self-administration. This supports the notion that decreasing the anxiogenic effects of cocaine increases the rewarding value in a dopamine independent manner. Therefore, increasing the aversive effects of cocaine might be a novel approach to fight cocaine dependence. In the second study, I studied cocaine-induced associative learning and changes in affect during cocaine conditioning and extinction. 50-kHz ultrasonic vocalizations (USVs) in rats are thought to reflect positive affect and occur upon appetitive stimuli and with cocaine delivery. First, I explored whether USVs might be elicited in anticipation of impending drug delivery. Shortly into conditioning, rats elicited USVs when placed in the cocaine-associated environment. USVs progressively increased, indicating a growing learned association between cocaine intake and cocaine-associated cues. This suggests that USVs may be a useful model for investigating cocaine craving and serve as a pharmacological target for interventions aimed to reduce cocaine craving and relapse. I then examined the effects of short-term deprivation of cocaine and cocaine cues on cocaine-conditioned USVs, which were both exaggerated after abstinence. The results may have clinical implications, in that intermittently avoiding cues or context may enhance drug cue salience and increase the probability of relapse. Motivational aspects of cocaine were assessed comparing commonly measured lever response rate and locomotion with cocaine-induced USVs during cocaine administration and extinction. In agreement with prevailing findings, lever responding for cocaine and cocaine-induced locomotor activity increased across conditioning sessions. However, the number of USVs evoked in response to cocaine infusion decreased with cocaine experience. These findings suggest growing tolerance to the rewarding properties of cocaine. These studies underscore the value of USV assessment during drug dependence studies. / text

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