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Dual task performance and the interaction of tasks has been the subject of much research. When tasks are performed together they affect each other to varying degrees depending upon such factors as the similarity of the tasks, their difficulty, and whether one task is given preference over another. In this study, task preference was investigated under divided attention conditions in order to determine what effect preference had on task performance. Twenty young adults took part in this study and were randomly assigned into two groups. Each group was experimentally motivated to favor one of the two tasks – either speaking a "tongue-twister" or tracking a moving target on a screen with a computer mouse. Each participant performed the tasks in both an isolated and combined conditions. The measurements of task performance (tracking scores, utterance duration, lower lip and jaw displacement, lower lip and jaw velocity, upper lip-lower lip correlation, spatiotemporal index, and sound pressure level) were then analyzed to determine how task preference affected the participant's performance. It was expected that the preferred task's performance would not suffer when performed in the dual task situation. Although some trends were noted in the predicted direction, no statistically significant results were found as a function of task preference. There were, however, some gender effects. Men were found to have significantly higher intensity than women during the speaking tasks in both the dual and isolated task conditions, and they were also found to perform better than women on the motor tracking task in both the dual and isolated task conditions.

Research in dual task performance varies widely in its methodology and results. The present study employed three different types of activity to provide insights into the interference that occurs in dual task performance. Twenty young adults completed a speech task (repeating a sentence), a verbal fluency task (listing words beginning with the same letter), and right- and left-handed motor tasks (placing pegs and washers in a peg board) in isolation and in concurrent conditions. Speech kinematic data revealed that during concurrent performance of manual tasks, lip displacement and peak velocity decreased, while sound pressure level and spatiotemporal variability increased. The impact of manual motor performance on speech differed between the right and left hand. Manual motor scores significantly decreased when concurrently performed with the verbal fluency task. Also, verbal fluency results declined when performed concurrently with left-handed manual motor task. These findings suggest that cortical localization of control may be more complex than is predicted by the functional distance hypothesis.

User interface design and development for ubiquitous software applications is challenged by the presence of varying contexts. Context comprises of user'­s computing platform, the environment in which the user is interacting with the application and user characteristics which comprise of user's behavior during interaction and user preferences for interface display and interaction. We present a framework for adaptive user interface generation where adaptation occurs when context changes. This framework introduces three new concepts. First, formalization for representing context is introduced. Our design of context specification is unique since it reflects the association of context with level and nature of user interface adaptation. Secondly, user interface generation life cycle is studied and we define a context model on top of task model to introduce the contextual conditions into user interface generation process. Using the context model, user interface designer can specify contextual requirements and its effect on the user interface. Third, context aware adaptation of user interfaces is achieved by mapping context specifications to various levels of user interface generation life cycle. We designed a specification language called rule specification using which the user interface designer can specify the mapping. With the new design of context representation, context model, and rule specification, we demonstrate how changes in contexts adapts task model which in turn adapts the user interface. / Master of Science