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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.
131

Facteurs influencing haptic shape perception

Toderita, Iuliana 12 1900 (has links)
Le but de cette étude était de déterminer la contribution de plusieurs facteurs (le design de la tâche, l’orientation d’angle, la position de la tête et du regard) sur la capacité des sujets à percevoir les différences de formes bidimensionnelles (2-D) en utilisant le toucher haptique. Deux séries d'expériences (n = 12 chacune) ont été effectuées. Dans tous les cas, les angles ont été explorés avec l'index du bras tendu. La première expérience a démontré que le seuil de discrimination des angles 2-D a été nettement plus élevé, 7,4°, que le seuil de catégorisation des angles 2-D, 3,9°. Ce résultat étend les travaux précédents, en montrant que la différence est présente dans les mêmes sujets testés dans des conditions identiques (connaissance des résultats, conditions d'essai visuel, l’orientation d’angle). Les résultats ont également montré que l'angle de catégorisation ne varie pas en fonction de l'orientation des angles dans l'espace (oblique, verticale). Étant donné que les angles présentés étaient tous distribués autour de 90°, ce qui peut être un cas particulier comme dans la vision, cette constatation doit être étendue à différentes gammes d'angles. Le seuil plus élevé dans la tâche de discrimination reflète probablement une exigence cognitive accrue de cette tâche en demandant aux sujets de mémoriser temporairement une représentation mentale du premier angle exploré et de la comparer avec le deuxième angle exploré. La deuxième expérience représente la suite logique d’une expérience antérieure dans laquelle on a constaté que le seuil de catégorisation est modifié avec la direction du regard, mais pas avec la position de la tête quand les angles (non visibles) sont explorés en position excentrique, 60° à la droite de la ligne médiane. Cette expérience a testé l'hypothèse que l'augmentation du seuil, quand le regard est dirigé vers l'extrême droite, pourrait refléter une action de l'attention spatiale. Les sujets ont exploré les angles situés à droite de la ligne médiane, variant systématiquement la direction du regard (loin ou vers l’angle) de même que l'emplacement d'angle (30° et 60° vers la droite). Les seuils de catégorisation n’ont démontré aucun changement parmi les conditions testées, bien que le biais (point d'égalité subjective) ait été modifié (décalage aux valeurs inférieurs à 90°). Puisque notre test avec le regard fixé à l’extrême droite (loin) n'a eu aucun effet sur le seuil, nous proposons que le facteur clé contribuant à l'augmentation du seuil vu précédemment (tête tout droit/regard à droite) doit être cette combinaison particulière de la tête/regard/angles et non l’attention spatiale. / The purpose was to determine the contribution of several factors (design of the task, angle orientation, head position and gaze) to the ability of subjects to perceive differences in twodimensional (2-D) shape using haptic touch. Two series of experiments (n=12 each) were carried out. In all cases the angles were explored with the index finger of the outstretched arm. The first experiment showed that the mean threshold for 2-D angle discrimination was significantly higher, 7.4°, than for 2-D angle categorization, 3.9°. This result extended previous work, by showing that the difference is present in the same subjects tested under identical conditions (knowledge of results, visual test conditions, angle orientation). The results also showed that angle categorization did not vary as a function of the orientation of the angles in space (oblique, upright). Given that the angles presented were all distributed around 90°, and that this may be a special case as in vision, this finding needs to be extended to different ranges of angles. The higher threshold with angle discrimination likely reflects the increased cognitive demands of this task which required subjects to temporarily store a mental representation of the first angle scanned, and to compare this to the second scanned angle. The second experiment followed up on observations that categorization thresholds are modified with gaze direction but not head position when the unseen angles are explored in an eccentric position, 60° to the right of midline. This experiment tested the hypothesis that the increased threshold when gaze was directed to the far right might reflect an action of spatial attention. Subjects explored angles located to the right of midline, systematically varying the direction of gaze (away from or to the angles) along with angle location (30° and 60° to the right). Categorization thresholds showed no change across the conditions tested, although bias (point of subjective equality) was changed (shift to lower angle values). Since our testing with far right gaze (away) had no effect on threshold, we suggest that the key factor contributing to the increased threshold seen previously (head forward/gaze right) must have been this particular combination of head/gaze/angles used and not spatial attention.
132

Le secteur de l’aviation et les règles de concurrence de l’Union européenne : étude des comportements et des rapprochements d’entreprises / The aviation sector and the European Union's competition rules : Study on conducts and rapprochements of undertakings

Vougioukas, Dimitrios 10 February 2012 (has links)
L’application des règles de concurrence de l’Union européenne au secteur de l’aviation présente un caractère spécial. Les rapprochements des compagnies aériennes sous formes d’alliances ou concentrations sont à première vue indispensables, afin de garantir leur viabilité et mieux desservir les besoins des voyageurs. La pression concurrentielle exercée par les différents moyens de transports et la globalisation des échanges conduisent vers cette voie. Or, la consolidation du marché aérien peut avoir des conséquences néfastes au détriment des consommateurs. Structure oligopolistique, organisation des gros opérateurs en réseaux (hub-and-spoke system), insuffisance des infrastructures, coûts énormes d’exploitation ainsi que protectionnisme au niveau international, constituent des barrières considérables à l’entrée de nouveaux concurrents et peuvent conduire à des pratiques abusives. La transparence tarifaire et les accords de coopération peuvent favoriser les cartels entre transporteurs aériens. La Commission évalue la position des parties et les risques à la concurrence sur des liaisons déterminées (paires de villes). Cette méthode de délimitation du marché pertinent au transport aérien suscite une polémique de la part notamment des compagnies aériennes qui soutiennent une approche fondée sur la concurrence entre réseaux. Ce débat, montre l’évolution du secteur de l’aviation et la nécessité de prendre toujours en compte les nouvelles données. Le maintien d’une concurrence efficace au secteur de l’aviation n’est pas un objectif en soi, mais un instrument de la politique européenne pour la création du « ciel unique européen ». L’intervention des autorités de l’Union européenne au secteur de l’aviation ne se limite pas à une application rigoureuse des règles de concurrence mais vise à éliminer préalablement les phénomènes anticoncurrentiels par l’adoption d’un cadre législatif. / The application of European Union’s competition rules to the aviation sector presents a special character. The rapprochement of air companies either by the formation of alliances or mergers seem to be necessary. Indeed, it can guarantee the existence of a company as well as it serves the needs of travellers. The competitive pressure exercised by the different existing means of transportation and the globalisation of exchanges lead to this behaviour. But this consolidation of the air market can have harmful consequences for consumers. Oligopolistic structures, the hub-and-spoke system, insufficiency of infrastructures, enormous costs of exploitation along with protectionism at an international level, constitute considerable barriers for new competitors and could lead to abusive practices. Tariff transparency and cooperative agreements can furtherer cartels in between air transporters. The Commission assesses the position of the parties and competitive risks on specific routes (city pairs). This method of delimitation of the market for air transport has created a polemic, especially from the airline companies supporting an approach based on competition between networks. This debate shows the evolution of the aviation sector and the necessity of always taking into consideration new data. The upholding of an efficient competition system within the aviation sector is not an objective in itself, but means of European politic for the creation of a “Single European Sky”. The intervention of European authorities within the aviation sector is not limited to a rigorous application of competition rules but aims first at eliminating anticompetitive phenomenon by adopting a legislative framework.
133

Facteurs influencing haptic shape perception

Toderita, Iuliana 12 1900 (has links)
Le but de cette étude était de déterminer la contribution de plusieurs facteurs (le design de la tâche, l’orientation d’angle, la position de la tête et du regard) sur la capacité des sujets à percevoir les différences de formes bidimensionnelles (2-D) en utilisant le toucher haptique. Deux séries d'expériences (n = 12 chacune) ont été effectuées. Dans tous les cas, les angles ont été explorés avec l'index du bras tendu. La première expérience a démontré que le seuil de discrimination des angles 2-D a été nettement plus élevé, 7,4°, que le seuil de catégorisation des angles 2-D, 3,9°. Ce résultat étend les travaux précédents, en montrant que la différence est présente dans les mêmes sujets testés dans des conditions identiques (connaissance des résultats, conditions d'essai visuel, l’orientation d’angle). Les résultats ont également montré que l'angle de catégorisation ne varie pas en fonction de l'orientation des angles dans l'espace (oblique, verticale). Étant donné que les angles présentés étaient tous distribués autour de 90°, ce qui peut être un cas particulier comme dans la vision, cette constatation doit être étendue à différentes gammes d'angles. Le seuil plus élevé dans la tâche de discrimination reflète probablement une exigence cognitive accrue de cette tâche en demandant aux sujets de mémoriser temporairement une représentation mentale du premier angle exploré et de la comparer avec le deuxième angle exploré. La deuxième expérience représente la suite logique d’une expérience antérieure dans laquelle on a constaté que le seuil de catégorisation est modifié avec la direction du regard, mais pas avec la position de la tête quand les angles (non visibles) sont explorés en position excentrique, 60° à la droite de la ligne médiane. Cette expérience a testé l'hypothèse que l'augmentation du seuil, quand le regard est dirigé vers l'extrême droite, pourrait refléter une action de l'attention spatiale. Les sujets ont exploré les angles situés à droite de la ligne médiane, variant systématiquement la direction du regard (loin ou vers l’angle) de même que l'emplacement d'angle (30° et 60° vers la droite). Les seuils de catégorisation n’ont démontré aucun changement parmi les conditions testées, bien que le biais (point d'égalité subjective) ait été modifié (décalage aux valeurs inférieurs à 90°). Puisque notre test avec le regard fixé à l’extrême droite (loin) n'a eu aucun effet sur le seuil, nous proposons que le facteur clé contribuant à l'augmentation du seuil vu précédemment (tête tout droit/regard à droite) doit être cette combinaison particulière de la tête/regard/angles et non l’attention spatiale. / The purpose was to determine the contribution of several factors (design of the task, angle orientation, head position and gaze) to the ability of subjects to perceive differences in twodimensional (2-D) shape using haptic touch. Two series of experiments (n=12 each) were carried out. In all cases the angles were explored with the index finger of the outstretched arm. The first experiment showed that the mean threshold for 2-D angle discrimination was significantly higher, 7.4°, than for 2-D angle categorization, 3.9°. This result extended previous work, by showing that the difference is present in the same subjects tested under identical conditions (knowledge of results, visual test conditions, angle orientation). The results also showed that angle categorization did not vary as a function of the orientation of the angles in space (oblique, upright). Given that the angles presented were all distributed around 90°, and that this may be a special case as in vision, this finding needs to be extended to different ranges of angles. The higher threshold with angle discrimination likely reflects the increased cognitive demands of this task which required subjects to temporarily store a mental representation of the first angle scanned, and to compare this to the second scanned angle. The second experiment followed up on observations that categorization thresholds are modified with gaze direction but not head position when the unseen angles are explored in an eccentric position, 60° to the right of midline. This experiment tested the hypothesis that the increased threshold when gaze was directed to the far right might reflect an action of spatial attention. Subjects explored angles located to the right of midline, systematically varying the direction of gaze (away from or to the angles) along with angle location (30° and 60° to the right). Categorization thresholds showed no change across the conditions tested, although bias (point of subjective equality) was changed (shift to lower angle values). Since our testing with far right gaze (away) had no effect on threshold, we suggest that the key factor contributing to the increased threshold seen previously (head forward/gaze right) must have been this particular combination of head/gaze/angles used and not spatial attention.
134

Zvláštní odpovědnost podniku v dominantním postavení / Special liability of businesses in dominant position

Čechráková, Iva January 2016 (has links)
Title: Special responsibility of undertaking in dominant position Author: Iva Čechráková Department: Department of Business Law Supervisor: JUDr. Daniel Patěk, Ph.D Abstract: This thesis deals with the doctrine of special responsibility of the dominant undertaking and related issues. The special responsibility of the dominant undertaking is the obligation not to allow its conduct to impair genuine undistorted competition on the common market. The doctrine of the special responsibility is tied to the prohibition on abuse of such position. One concept could not be assessed without the other, because the concept of special responsibility of the dominant undertaking is a fundamental principle for the application of the prohibition on abuse of such position. Based on that it is necessary to describe in this thesis the prohibition on abuse of dominant position together with selected prohibited practices, in which the special responsibility of the dominant undertaking is reflected. This responsibility presupposes a higher standard of vigilance reflected in the conduct of such an undertaking, because an undertaking in dominant position on the relevant market could not take all actions that the other undertakings lacking such market power could do. The question of the superdominant undertakings and the scope of...
135

Upplevd Yrkesstatus och Stress : Vad skapar upplevd yrkesstatus och har yrkesstatus samband med stress?

Westberg, Nathalie, Persson, Sara January 2015 (has links)
This study examines subjective occupational status and what factors influence and indicate subjective occupational status among employees in the municipal sector. The study also investigates if subjective occupational status has any significant connections with stress and worrying. The aim of this study is to examine if income, education, age, gender and length of employment has any significant effect on the subjective occupational status. We also aim to investigate if subjective occupational status affects the respondent’s levels of stress and worry. The material for the study was collected via a questionnaire with 268 respondents. The survey was done via the internet and sent out to the respondents via e-mail. We are utilizing the reference group theory in our analysis of the material. Reference group theory states that subjective social position is created by social comparison. Individuals tend to base their position in the social hierarchy and compare themselves with individuals who are similar to them. This leads to that many people places themselves as average. The results of the study show that it is only income which is affecting the subjective occupational status. We also found that subjective occupational status does not have any connections with stress apart from causing the respondents some worry over not having time to complete their work assignments.
136

BASELINE COMMUNICATIONS SYSTEM FOR A SMALL SATELLITE

Orozco, Gina 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The NMSUSat is part of the AFRL/NASA University Nanosatellite program. The constellation will consist of a main microsatellite that will have a command link from ground and a telemetry link to ground while a picosatellite will act as a sensor reporting data to the microsatellite. Innovative command and data handling will be incorporated at low cost and greater accessibility. In this paper we present the necessary communications and control architecture for the space segment and the ground segment of the nanosatellite.
137

The relative effect of manipulation and core rehabilitation in the treatment of acute mechanical low back pain in sedentary patients

Higgs, Renee Joy January 2007 (has links)
Dissertation submitted in partial compliance with the requirements for the Master’s Degree in Technology: Chiropractic, Durban University of Technology, 2007. / The aim of this research was to investigate the relative effectiveness of manipulation versus core rehabilitation in the treatment of acute mechanical low back pain in sedentary patients. Recent research has found that dysfunction of the primary core stabiliser muscles is linked with an increasing number of the general population suffering from low back pain; this is thought to be due to the fact that people in general are living more sedentary lifestyles. The Aims and Objectives of this study were to determine the relative effect of manipulation and core rehabilitation in sedentary patients suffering from acute mechanical low back pain in terms of subjective findings, objective findings and to determine any correlations between these findings Thirty-two participants, with acute low back pain participated in the study. They received treatment over a period of three weeks, two treatments in the first week, two treatments in the second week and a follow up seven days later. Group A received a spinal manipulation while Group B received core rehabilitation exercises. Readings were taken at three time points, namely visit one, three and five before the treatment, they included the following readings: Numerical Pain Rating Scale, Algometer, Roland Morris Low Back Pain and Disability Questionnaire, Biofeedback Stabiliser and the Surface EMG. The results showed that there was no differential (p<0.05) treatment effect between the two Groups, and that both Groups showed a clinical improvement in their low back pain. In conclusion, it appears that even though both these treatment protocols have very different mechanisms of action, both can be effective treatment protocols and that core rehabilitation exercises when properly performed are as effective as manipulation in the treatment of acute low back pain.
138

COMBINING TECHNOLOGIES TO FOSTER IMPROVED TSPI ACCURACY AND INCREASE SHARING OF THE FREQUENCY SPECTRUM

Switzer, Earl R., Wrin, John, Huynh, James 10 1900 (has links)
International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The loss of radio frequency (RF) spectrum for use in testing has steadily increased the likelihood that users of the few remaining frequencies available to test ranges will experience scheduling conflicts and interference with nontest users. A gradual increase in the base of test customers engaged in scientific, military, and commercial R&D, point toward a near term situation in which more test customers will be competing for fewer frequencies. The test ranges, often operating in close geographical proximity with other communications-intensive functions as well as with each other, will also encounter increasing out-of-band and adjacent-channel interference. This projected growth of R&Drelated testing constrained to operate in a diminished RF spectrum (and a more confined test space), will undoubtedly stimulate the development of new products that make more efficient use of the RF spectrum. This paper describes one such innovative approach to spectrum sharing. The authors assess the operational need for an affordable miniaturized avionics instrument package based on a C-band radar transponder integrated with a Global Positioning System/Inertial Measurement Unit (GPS/IMU). The proposed approach would make use of frequencies already allocated for use by existing C-band aeronautical transponders. It would augment the format of the transponder output data to include the vehicle position obtained from an onboard GPS/IMU. Existing range instrumentation radars, such as the venerable AN/FPS-16, could be modified with lowcost upgrade kits to provide uniformly higher accuracy over the entire transponder coverage range.
139

MULTIPLE TARGET INSTRUMENTATION RADARS FOR MILITARY TEST AND EVALUATION

MILWAY, WILLIAM B. 10 1900 (has links)
International Telemetering Conference Proceedings / October 28-31, 1985 / Riviera Hotel, Las Vegas, Nevada / Military aerospace test ranges are increasingly being called upon to conduct missions utilizing large numbers of participating units, or targets. Precision, position and trajectory data must be recorded on all participants. In addition, weapon/target engagements must be scored and real-time range safety considerations must be accommodated. This requires precision metric data be available in real-time on all participating targets. One solution to these problems, is utilization of multiple target tracking radars which incorporate electronic beam steering to quickly move from one target to another in sequence. This paper briefly recounts the history of range instrumentation radars, points out some of the advantages of using multi-target radars, and highlights the specifications and design of a multiple target instrumentation radar now being acquired by the U.S. Army for use at White Sands Missile Range and the Kwajalein Missile Range.
140

ADVANCED TELEMETRY TRACKING SYSTEM DEVELOPMENT AT WHITE SANDS MISSILE RANGE

Sharp, Phillip D. 11 1900 (has links)
International Telemetering Conference Proceedings / November 04-07, 1991 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Early in the 1980s White Sands Missile Range (WSMR) began studying the problem of updating the Telemetry Tracking Systems (TTS) used to support test range missions. The information and equipment available at that time indicated that very little technology advancement had occurred in the area of TTS. Because the TTS usually have a long service life, it was imperative that the new or updated systems be as good as the state-of-the-art in todays technology could produce. Because of the lack of technology advancements, it was evident that drastic measures would be required to achieve the objectives of the update effort. These findings resulted in a program called the Advanced Telemetry Tracking System Integration and Development (ATTSID). Its objective was to determine if it was possible to apply advanced computer technology to the solution of servosystem problems characteristic in most TTS. This paper and three related papers, The Advanced Telemetry Tracking Servosystem; An Automated Testing System for a Telemetry Tracking System; and The Microcomputer-based Digital Controller for the Advanced Telemetry Tracking System; document the objectives, design considerations, fabrication and evaluation of a prototype TTS. It utilizes a dedicated computer system to control, compensate the servo position loop, and provide automated testing of the servo and RF receiving systems. This computer system was installed and evaluated in one of the WSMR Transportable Telemetry Acquisition Systems (TTAS) for evaluation and refinement of the system. The results of this program will determine the evolution of TTS and extend the use of computer technology to providing more reliable and accurate telemetry tracking support of test range operations.

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