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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.
411

Revitalization movements in Melanesia: a descriptive analysis

Everett, Michael W. January 1968 (has links)
No description available.
412

An eye movement dependent visual attention model and its application /

Jie, Li, 1976- January 2008 (has links)
In this dissertation, we study the relationship between eye movements and visual attention. Different types of eye movements are investigated including microsaccades, eye fixation, and eye pursuit. First, we demonstrate that microsaccades occur during pursuit and they are linked to covert attention shifts. Employing a psychophysical task that involves covert attention shifts to a peripheral square, we detect if microsaccades occur during eye pursuit, and, if so, whether, and in what way, microsaccades are related to attention shifts. Microsaccades are found to occur during pursuit and they present in similar patterns as those occurring during eye fixation. We discover that microsaccades tend to be biased towards the same direction as pursuit and the bias increases with increases of pursuit velocities. Through the analysis of microsaccade orientation and latency, we argue that microsaccades occurring during pursuit, rather than being randomly distributed, have a link with covert attention shifts. This is consistent with what has been reported for microsaccades occurring during fixation. Further analysis of microsaccade amplitude supports this argument. The potential attention mechanisms for the characteristics of microsaccades are discussed. We suggest that the attention allocation during pursuit is responsible for the characteristics of microsaccades. Our analyses of microsaccades also enforce the argument that microsaccades may be the suppressed saccades. / In addition to microsaccades, the attention allocation during eye fixation and eye pursuit are considered as well. We demonstrate that, during eye fixation, the local image content around the area of a fixation point is a significant factor to influence the fixation duration. However, during pursuit, the pursuit direction, rather than image contents, is important to decide attention allocation. According to these results, a top-down attention model based on types of eye movements is built. Three types of eye movements are considered separately in the model. They are eye fixation, eye pursuit, and saccadic eye movements (including microsaccades). The model is applied to the design of an interactive 2D video game. We demonstrate that the game is successfully designed in different difficulty levels through the analysis of attention allocation by our attention model. Our results imply that the attention modeling can be used to alter the game play so as to provide varying difficulty levels and it is also promising to take advantage of eye tracking data for broader applications, such as for navigation, intelligent map searching, augmented reality, and others.
413

The polyvocal fugue : frame and counter-frame in the management of an environmental health conflict

Bassett, Beverly Raewyn 05 1900 (has links)
It began with the loss of the use of her forearm, then the use of her other arm, and then her legs. Headaches became severe migraines; seizures occurred. Her body wasted away and she became needle-thin. A neurologist, a psychiatrist, her family physician could not determine what was wrong. A local specialist, however, recognized the symptoms as those he had seen in others over several years. Concerned that the symptoms might be related to environmental toxins, he alerted the local health authorities. His concerns and those of his patients were not taken seriously, not, that is, until he and his patients coined a name for the symptoms: Somatic Chemically Induced Dysfunction Syndrome, or SCIDS. What was expected to be simply a name for a set of symptoms suddenly became contested. A social problem was defined, and experts from Agriculture, Health, and the Environment Ministries entered the fray. Unrelated at first, degradation of the local aquifer, death of wildlife, and a noticeable decrease in small mammals in the area had been noted. Questions were raised about the links between the two; between the environment and health. Somatic Chemically Induced Dysfunction Syndrome (SCIDS) suggested a causal link with chemicals, moreover with chemicals in the environment. This raised doubts in people's minds about the responsibility and accountability of government, and the authority of experts and the role of science was thrown into question. A private trouble became a public issue. The ensuing conflict revolved around naming and owning a social problem. Both experts and persons with SCIDS invoked science to make their case. Sides were drawn and the conflict was played out to the wider public through the media. It has been commented that research about illnesses of the environment have a bias towards the stories of the sufferers. This dissertation focuses mainly, though not exclusively, on the stories of the various experts involved. Set within the wider frame of social constructionism, I address the ways in which private troubles become public issues and are defined as a social problem. The frames used in this contest to wrest both ownership and thus management of the problem are investigated. The impact of this on a local social movement is examined.
414

Gaze selection in the real world : finding evidence for a preferential selection of eyes

Birmingham, Elina 11 1900 (has links)
We have a strong intuition that people's eyes are unique, socially informative stimuli. As such, it is reasonable to propose that humans have developed a fundamental tendency to preferentially attend to eyes in the environment. The empirical evidence to support this intuition is, however, remarkably thin. Over the course of eight chapters, the present thesis considers the area of social attention, and what special role (if any) the selection of eyes has in it. Chapters 2 and 3 demonstrate that when observers are shown complex natural scenes, they look at the eyes more frequently than any other region. This selection preference is enhanced when the social content and activity in the scene is high, and when the task is to report on the attentional states in the scene. Chapters 4 and 5 establish that the bias to select eyes extends to a variety of tasks, suggesting that it may be fundamental to human social attention. In addition, Chapter 5 shows that observers who are told that they will have to remember the scenes look more often at the eyes than observers who are unaware of the forthcoming memory test; moreover this difference between groups persists to scene recognition. Chapter 6 examines whether the preference for eyes can be explained by visual saliency. It cannot. Chapter 7 compares the selection of eyes to another socially communicative cue, the arrow. The results shed light on a recent controversy in the social attention field, and indicate again that there is a fundamental bias to select the eyes. Collectively the data suggest that for typically developing adults, eyes are rich, socially communicative stimuli that are preferentially attended to relative to other stimuli in the environment.
415

Working memory capacity and the control of saccades : individual differences in executive control

Unsworth, David I. 08 1900 (has links)
No description available.
416

Characteristic behaviour of slow moving slides

Mansour, Mohamed Unknown Date
No description available.
417

Friendship in the Peace Movement

Forman, Gideon January 1990 (has links)
The thesis suggests a way in which the peace movement can make itself attractive to citizens. It begins with the assumption that the movement should satisfy some of their personal needs. One such need is that of relief from the pains of anxiety. Drawing upon Heidegger, the thesis outlines two of these pains--impotence and unheimlichkeit--and shows why we experience them. Then, using Aristotle's Nicomachean Ethics, it explains why true friendship is a positive response to the pains. True friends further each other's courage, a virtue whose possession helps them to weather impotence. True friends are, in fundamental ways, the same as one another: Their partial identity counters the effects of non-humans whose radical otherness makes the partners feel unheimlich. / A movement which promotes true friendship within its ranks--and publicizes this fact--will likely attract new members and have success in retaining old ones. The last chapter discusses, in concrete terms, how friendship among movement members can be fostered.
418

Learning and retention adaptations of myoelectric activity during a novel multi-joint task

Sarantinos, George D. V. January 1999 (has links)
The learning and retention adaptations of muscle activity were studied during a novel multi-joint task. Electromyographic (EMG) signals were recorded from the posterior deltoid, long and lateral heads of the triceps, pectoralis major, biceps and brachioradialis muscles. These data were assayed in a pattern recognition analysis (SVD) to ascertain the minimum number of 'common features' or waveforms (W's) required to describe the set of input EMG patterns (IP). / Fifteen participants performed targeted arm movements, which incorporated the shoulder and elbow articulations, as fast and as accurately as possible in the horizontal plane. Both experimental (E) and control (C) groups were employed. The E group was trained (Day 1 to Day 4) and tested both pre- and post-learning. They were further re-tested during a retention period (RET) consisting of 1, 2, 4, 6 and 8 week post-learning sessions. The C group was tested before and after learning and at the end of the RET period. (Abstract shortened by UMI.)
419

Musculo-skeletal geometry and the control of single degree of freedom elbow movements

Gribble, Paul L. January 1995 (has links)
Empirical and modelling studies are reported which explore ways in which the central nervous system might consider musculo-skeletal geometry when generating commands for single degree of freedom elbow flexion and extension movements. In a series of experiments it is shown that subjects do not perform rapid, goal-directed flexion and extension movements equally accurately in different parts of the elbow's workspace. In these experiments, movements of 10, 20 and 30 degrees in amplitude were tested using up to five different initial elbow angles. When performing flexions, subjects tended to overshoot targets when starting from extended positions, to undershoot targets when starting from more flexed positions, and to perform relatively accurate movements when starting from the centre of the workspace. Final position accuracy was more variable for extensions. When reliable differences existed for extensions, subjects tended to produce a pattern of results opposite to that of flexions: subjects overshot targets when starting from flexed positions and undershot targets when starting from more extended positions. A model of elbow movement based on the $ lambda$ version of the equilibrium-point hypothesis was used to assess the extent to which the pattern of errors obtained in the empirical studies could be reproduced by a control scheme that does not adjust commands in response to changing musculo-skeletal geometry, but rather uses one single invariant command throughout the workspace. The motivation for testing the invariant command notion was to explore the possibility that motion planning might be achieved without an explicit representation of musculo-skeletal geometry. Predicted patterns of final position errors across the workspace matched empirically obtained error patterns for flexions, but the model performed less well when predicting the pattern of errors observed for extension movements.
420

Patterns of interlimb coordination during asymmetrical reaching movements

Hatzitaki, Vassilia January 1995 (has links)
The present study investigated the patterns of interlimb organization during the concurrent performance of asymmetrical reaching movements. The inherent tendency towards interlimb synchronization often constrains activities requiring the two limbs to move over different distances or at different movement speeds. The study of bimanual coordination has shown that the amount of interlimb interference during bilateral performance of asymmetrical actions, is regulated according to the magnitude characteristics of the variable used to introduce the asymmetry between the limbs. The purpose of the present study was to examine the relationship between the degree of interlimb decoupling and the magnitude of the asymmetry between the limbs. Asymmetry was systematically manipulated by scaling the magnitude of the interlimb difference in final target distance, during bimanual performance of reaching movements. The degree of interlimb decoupling was reflected in the movement time, muscle activity onset and joint torque relationship between the limbs. / Decoupling of the asymmetrical limb movements was effected by an earlier onset of the antagonist muscles in the constrained limb which scaled the amount of muscle torque production and therefore the stiffness of the limb during the acceleration phase of the movement. Thus, the movement amplitude differentiation was achieved by an initial accelarative impulse attributed to the differential control of the muscle torque production at each joint. On the other hand, the interactive forces played a secondary role in the degree of decoupling process. Overall, the degree of decoupling scaled according to the magnitude of the interlimb difference in distance; the greater the asymmetry, the greater the differentiation between the limbs. However, systematic variations of the interlimb asymmetry in distance gave rise to a wide variety of individual decoupling trends. Bimanual practice of the asymmetrical reaching tasks did not result in the development of more independent limb movements. The results of the present study have implications to human factor design and ergonomics.

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