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The current study utilized laboratory tasks (Conners' Continuous Performance Test, CPT; Behavioral Inhibition Task, BIT) to examine the relationships among motivation, executive functioning, and parent and teacher-reported attention, internalizing, and externalizing problems in a clinical sample of 132 children with or without Attention-Deficit/Hyperactivity Disorder, Combined Type (ADHD-C; 69% male, mean age = 9.88). Specificity was examined through total, unique, and interactive effects via hierarchical regression. Higher CPT scores (i.e., executive disinhibition) were related to greater externalizing problems in total and unique effect analyses, while a relationship between lower CPT scores (i.e., executive inhibition) and greater internalizing problems was found only in unique effect analyses. No significant effects were found for motivational inhibition (i.e., low BIT) or disinhibition (i.e., high BIT). ADHD-C was associated with greater attention and externalizing problems in total effect analyses, but only externalizing problems showed a significant relationship in unique effect analyses. Interactive effects were found for ADHD-C and executive functioning, as lower levels of CPT (i.e., executive inhibition) coupled with ADHD-C resulted in greater parent-reported attention problems. In addition, higher CPT scores (i.e., executive disinhibition) were associated with greater parent-reported externalizing problems in Non-ADHD-C children. Although some main effects were predicted, the interactive effects were somewhat surprising, particularly in relation to ADHD-C, executive inhibition, and parent-reported attention problems. Exploratory analyses revealed that this effect may have been due to greater internalizing problems in ADHD-C children at lower levels of CPT (i.e., executive inhibition). Results are discussed in relation to past studies and laboratory task validity. / Master of Science

The present study investigated the effect of anticipated feedback proximity (immediately after completing the task or one week later) on performance and the moderating role of self-efficacy and task types (analytical or creative). I hypothesized that expecting rapid feedback should yield better performance than expecting delayed feedback, for people with high self-efficacy or those who receive analytical tasks. For those who receive creative tasks or have low self-efficacy, expecting rapid feedback may produce negative impact on performance. The results indicated a trend of main effect of anticipated feedback proximity. Specifically, participants performed better when they expected immediate feedback relative to expecting delayed feedback, regardless of the task type. There was also a main effect of task type. Performance on the analytical tasks was better than performance on the creative tasks. However, neither self-efficacy nor task type moderated the effects of anticipated feedback proximity. The implications for these findings are discussed herein.

Many tasks in the real world require simultaneous processing of mental information alongside physical activity. Most of researchers have studied the impact of physical activities on simple cognitive tasks, but have neglected other important influences (such as different attentional resource pools, as well as gender). Therefore, this thesis proposes a new model that investigates the combined impact of physical and mental workload on different attentional resources (visual and auditory, verbal and spatial). This thesis presents three experimental studies that examined the effects of physical and mental workload interactions, as well as gender, on visual tasks performance and auditory tasks. This thesis uses different methods to evaluate the impacts of workload interactions on task performance: performance measure, physiological parameters and brain activity (Near-Infrared Spectroscopy (NIRS) method) and subjective assessment tools. Finally, this thesis translates the experimental studies setting into a field study to validate the model. Based on the experimental results, this research creates a new theoretical model that illustrates in general that physical activity is beneficial for performance on cognitive tasks (visual and auditory), particularly at low levels of workload interactions, while other workload interactions lead to worse performance on cognitive tasks. However, when physical activity was introduced, performance at the medium level of mental workload was equivalent to that in the low mental workload condition; furthermore, at the low mental workload, there were no differences in performance between low and medium physical workloads. The general pattern of results suggests that physical workload leads to better performance in these medium-demand conditions up to the higher level in the low-demand condition. A mechanism for this effect is proposed based on physiological arousal and brain oxygenation. This thesis further suggests that the NIRS is a valuable technique to reflect the influence of physical and mental workload interactions on brain activity. Finally, this thesis demonstrates the translation of experimental findings into a field setting to verify the new model as well as to make recommendations for job design.

Two continuous performance tests were administered to normal adult subjects. The mode of presentation (visual or auditory) and the type of task (vigilance or distractibility) were varied, and their effects on performance measured. Data were collected on eighty-two subjects, and results indicated that auditory presentation of stimuli increased the difficulty of both tasks. Results also suggest that the distractibility task administered in either mode was more difficult than the vigilance task. Intercorrelations among the four continuous performance tasks are provided. Normative data are presented on all four tasks administered. A measure of symptoms of attention-deficit disorder in adults, the Adult Behavior Checklist, was found to correlate significantly with another measure of pathology, the SCL-90-R.

Esta dissertação tem por objetivo apresentar a proposta de uma política de escalonamento para grids computacionais. Essa política, intitulada Dynamic Max-Min2x, é orientada ao escalonamento de aplicações cujas tarefas não realizam comunicação entre si e visa a redução do tempo de resposta dessas aplicações através da utilização de atribuição dinâmica de tarefas e replicação das mesmas. Experimentos, feitos através de simulação, mostram que o tempo médio de resposta de aplicações utilizando-se a Dynamic Max-Min2x é inferior ao de outras políticas da literatura. Análises dos resultados desses experimentos apontam que esse tempo tende a ser mais atrativo principalmente quando as tarefas necessitam de muito processamento e quando há grande variação de carga no sistema, caracteristicas comuns em grids computacionais. Além disso, esta dissertação apresenta a implementação de um framework utilizando-se o Globus Toolkit, onde é possível a inserção de políticas de escalonamento para a submissão inteligente de tarefas em um grid computacional. / This Master thesis proposes a new grid scheduling policy called Dynamic Max-Min2x. This policy focuses on applications in which tasks do not communicate among themsenves and targets a response time reduction of these applications through the use of dynamic task distribution and replication techniques. Experiments, done using simulations, have shown that the response time related to Dynamic Max-Min2x is smaller than others policies found in literature. Analysis of the results have demonstrated that this time tends to become more attractive when tasks do not need much processing power and when there is a great load variation in the system, characteristics frequently found in grids. Furthermore, this thesis presents the implementation of a framework using Globus Toolkit, which makes possible the new scheduling policies insertion to provide an intelligent submission tasks in a computational grid system.

Interdisciplinary Project Work (PW) was introduced as an educational initiative in Singapore schools from primary to pre-university levels in 2000. PW was posited to (a) enhance perceptions and use of inter-subject connections in real-world problems, (b) promote knowledge application, and (c) provide a platform for the use of thinking skills. The main goal of this thesis is to explore how these objectives are inter-related with factors influencing the quality of group collaborative mathematical thinking processes and mathematical outcomes during a mathematically-based interdisciplinary project. In this study, high quality mathematical thinking processes occur when the flow of group interactions is purposefully directed towards the enhancement of mathematically accurate, logical, and reasonable outcomes. / A Sequential Explanatory Mixed Methods Design consisting of consecutive quantitative and qualitative data collection and analysis procedures was used to answer the seven research questions in the study. A researcher-designed mathematically-based interdisciplinary project was implemented over 14-15 weeks with 16 classes of students (aged 13-14) belonging to two educational streams (higher and average-ability) in three Singapore government secondary schools. No teaching intervention was administered. Six scales were developed for pre- and post-project measurements of students’ mathematical confidence, perception of the value of mathematics, and perception of the interconnectedness of mathematics (N = 398). Ten student-group cases (n = 38) were selected for further in-depth qualitative data collection procedures pertaining to the nature of mathematical knowledge application, use of metacognitive monitoring and regulatory strategies, and core thinking skills application during three tasks in the interdisciplinary project. / The findings of this study clearly demonstrate the complexities of using PW to promote holistic and connected use of knowledge. Five substantial contributions to research on interdisciplinary learning arise from the thesis:1. An empirical framework synthesising factors influencing the quality of group collaborative mathematical knowledge application processes and outcomes was developed.2. The social influence of the group member activating applications of core thinking skills and metacognitive monitoring and regulatory strategies is a mediating factor influencing the flow of cognitive-metacognitive group interactions, and therefore, the quality of collaborative mathematical knowledge application processes and outcomes.3. Leaders of high-stream groups who were socially non-dominant but mathematically active were more likely to apply a higher frequency of core thinking skills than group members in other roles (i.e., questioner, recorder, and encourager) during a mathematically-based interdisciplinary project.4. The types and complexities of mathematical knowledge and skills applied during a mathematically-based interdisciplinary project did not correspond with stream.5. Whilst students were more able to appreciate the use of mathematics for inter-subject learning after participating in a mathematically-based interdisciplinary project, their beliefs about inter-subject connections and efforts at making these connections only marginally changed.These outcomes enhance our understanding of the challenges involved in the successful use of interdisciplinary tasks with middle school students and provide focuses for future teacher facilitation of mathematical learning during interdisciplinary education.

The Usability of a website can be evaluated using various methods. One of the methods is usability testing, which is widely used and employed by the usability tester due to its low cost and user friendliness. The results of usability testing can be affected positively or negatively by several factors such as evaluator’s role, number of users, test environment, tasks, usability problem report, usability measures, and other factors. For more than a decade, the number of users plays a key role in usability testing. Previously done study [12], has shown that correlation exists between the number of user tasks and the number of issues found. As an extension and follow-up of the recent studies, the current work was carried out on task design, task number, and task coverage. Two types of task designs were proposed namely, guided tasks and unguided tasks. Considering the task as a key factor, the remaining factors were also considered while employing the usability test.

It is widely held among cognitive aging researchers that older adults are at a disadvantage with respect to the division of attention between two or more concurrent tasks. Some researchers have attributed dual-task performance decrements to reduced processing speed with age while others have attributed declines in dual-task performance to the reduced efficiency of task coordination and control processes. Few researchers, however, have considered the possibility that age-related differences in dual-task performance may be related to underlying differences in the learning mechanisms supporting component task performance. Three studies were conducted which differed in the type of single-task training provided to young and old adult participants: Consistently mapped (CM), variably mapped (VM) and attenuated priority (AP) training. Skilled dual-task performance was then assessed as a function of both component task learning and age through a) the examination of initial and end-level skilled dual-task performance, b) transfer of learning to novel task combination and c) retention capability. It was predicted that type of component task training would moderate age-related differences in skilled dual-task performance. The results were confirmatory, however, were not completely consistent with initial predictions.

Interdisciplinary Project Work (PW) was introduced as an educational initiative in Singapore schools from primary to pre-university levels in 2000. PW was posited to (a) enhance perceptions and use of inter-subject connections in real-world problems, (b) promote knowledge application, and (c) provide a platform for the use of thinking skills. The main goal of this thesis is to explore how these objectives are inter-related with factors influencing the quality of group collaborative mathematical thinking processes and mathematical outcomes during a mathematically-based interdisciplinary project. In this study, high quality mathematical thinking processes occur when the flow of group interactions is purposefully directed towards the enhancement of mathematically accurate, logical, and reasonable outcomes. / A Sequential Explanatory Mixed Methods Design consisting of consecutive quantitative and qualitative data collection and analysis procedures was used to answer the seven research questions in the study. A researcher-designed mathematically-based interdisciplinary project was implemented over 14-15 weeks with 16 classes of students (aged 13-14) belonging to two educational streams (higher and average-ability) in three Singapore government secondary schools. No teaching intervention was administered. Six scales were developed for pre- and post-project measurements of students’ mathematical confidence, perception of the value of mathematics, and perception of the interconnectedness of mathematics (N = 398). Ten student-group cases (n = 38) were selected for further in-depth qualitative data collection procedures pertaining to the nature of mathematical knowledge application, use of metacognitive monitoring and regulatory strategies, and core thinking skills application during three tasks in the interdisciplinary project. / The findings of this study clearly demonstrate the complexities of using PW to promote holistic and connected use of knowledge. Five substantial contributions to research on interdisciplinary learning arise from the thesis:1. An empirical framework synthesising factors influencing the quality of group collaborative mathematical knowledge application processes and outcomes was developed.2. The social influence of the group member activating applications of core thinking skills and metacognitive monitoring and regulatory strategies is a mediating factor influencing the flow of cognitive-metacognitive group interactions, and therefore, the quality of collaborative mathematical knowledge application processes and outcomes.3. Leaders of high-stream groups who were socially non-dominant but mathematically active were more likely to apply a higher frequency of core thinking skills than group members in other roles (i.e., questioner, recorder, and encourager) during a mathematically-based interdisciplinary project.4. The types and complexities of mathematical knowledge and skills applied during a mathematically-based interdisciplinary project did not correspond with stream.5. Whilst students were more able to appreciate the use of mathematics for inter-subject learning after participating in a mathematically-based interdisciplinary project, their beliefs about inter-subject connections and efforts at making these connections only marginally changed.These outcomes enhance our understanding of the challenges involved in the successful use of interdisciplinary tasks with middle school students and provide focuses for future teacher facilitation of mathematical learning during interdisciplinary education.