The purpose of this study was to determine if task type, task complexity, and search mechanism would have a significant affect on task performance. The problem motivating this study is the potential for systems online help designers to construct systems that can improve the performance of computer users when they need help.

Consumers consistently pursue new beginnings regarding health, financial wellbeing, and personal growth. Conceptual metaphors like the "fresh start" can be powerful tools for reframing problems and motivating behaviors (Coulter and Zaltman 2000; Lakoff and Johnson 1980; Landau, Keefer and Meier 2010; Thibodeau and Boroditsky 2011), and are frequently featured in movies, blogs, strategic marketing communication, and products. However, research has not examined whether fresh starts can indeed help consumers set new goals and improve their performance. This dissertation seeks to explore the role of the fresh start metaphor in consumers' lives. In Chapter 2, I define the fresh start as consumers' pursuit of new beginnings, and develop a reliable scale distinct from related constructs such as optimism, hope, entity theory and psychological closure. I find that consumers who score higher on the fresh start scale focus on the future more optimistically, report higher intentions to set new goals, and increase efforts toward health and financial budgeting. In Chapter 3, I investigate whether actively engaging the metaphor of the fresh start can change consumer outcomes. I find that when participants are prompted to activate a fresh start they expect to perform better on a challenging task (e.g., losing weight or saving money) because it increases their belief that present obstacles will have less hold in the future. I also find that a fresh start translates into performance improvements when participants perform poorly on a task in a personally important domain, and self-efficacy mediates the effect. Overall, results provide strong support for the role of the fresh start as a powerful tool that consumers can use to improve well-being, overcome poor performance, set new goals, and transform for the better.

Background: Surgical checklists are in use as means to reduce errors for safer surgery. Checklists are infrequently applied during procedures and have been limited to lists of procedural steps as aid memoires. Aims: We aimed to formulate a performance based checklist and to study its effect on the surgical task performance of novice surgeons when applied during both, routine knot tying and simulated emergency laparoscopic tasks. We also aimed to study the effect of the performance based intra-procedural checklist in clinical environments during elective laparoscopic procedures as a way of error reduction mechanism and improvement of patient safety. Methods: The study was conducted in two settings, lab-based and clinical-based environments. The lab-based study was conducted during both routine and emergency tasks. Lab-based study- routine task: Twenty novices were randomised into two equal groups, those receiving paper feedback (control group), and those receiving paper feedback and the checklist that was applied at 20 seconds intervals (checklist group). The task involved performing laparoscopic double knots which were repeated over 5 separate stages. Human reliability assessment technique was used for error analysis on unedited video recordings of the tasks. Endpoints included number of errors, error probability (number of errors/number of knots), error types and number of completed knots. Non-parametric statistics were used for data analysis. Lab-based- emergency task: Thirty consented laparoscopic novices were exposed unexpectedly to a bleeding vessel in a laparoscopic virtual reality simulator as an emergency surgical scenario. The task consisted of using laparoscopic clips to achieve haemostasis. Subjects were randomly allocated into 2 equal groups; those using the checklist (checklist group) and those without (control group). The checklist was applied by the trainees in the checklist group at 20 seconds intervals. The surgical performance was computed on eight predetermined technical factors. Clinical-based study: Surgical trainees in the general surgery at Tayside NHS were included in this study and required the attendance of a trainer during the procedure as per routine practice. Record year of trainees and previous experience on laparoscopic cholecystectomy were noted. Two elective laparoscopic cholecystectomies for each trainee were video-recorded without the use of the checklist, directly followed by 2 further operations after the introduction of the checklist. The unedited videos were analysed for error detection using human reliability analysis technique. Total number of errors per time during each procedure, total number of errors per number of instrument movements, total number of instrument movements per time and number of trainer intervention while per time were noted as assessment points. Results: Lab-based- routine task: 2341 errors were detected in 141 tasks, 408 subtasks and 2249 steps during the 5 stages. During the first stage, the errors were not significantly different between groups. The checklist group committed significantly fewer errors as compared to the control group during all the later 4 stages (p < 0.01). The checklist group had an enhanced learning curve as the last 4 stages showed significant fewer errors compared to the first stage (p < 0.05), while the control group showed no improvement. Error probability was significantly higher in the control group compared to the checklist group: median [IQR] 32.6 [25.89] vs 11.7 [10.72] (p < 0.01). Individual error types during each step of the laparoscopic task were identified. The checklist group performed better with fewer errors for all the error types. While, there was no significant difference in each of 'the lack of supination', 'tissue bite' and 'out of vision'; the differences in all the rest of error types were highly statistically significant (p < 0.01). Number of completed knots was not statistically different between the 2 groups. Lab-based- emergency task: The checklist group performed significantly better in 6 out of 8 technical factors when compared to the control group median [IQR]: Right instrument path length (m) 1.44 [1.22] vs 2.06 [1.70] (p= 0.029), and right instrument angular path (degree) 312.10 [269.44] vs 541.80 [455.16] (p= 0.014), left instrument path length (m) 1.20 [0.60] vs 2.08 [2.02] (p= 0.004), left instrument angular path (degree) 277.62 [132.11] vs 385.88 [428.42] (p= 0.017). The checklist group committed significantly fewer number of errors in the number of badly placed clips (p= 0.035) and number of dropped clips (p= 0.012). Although statistically not significant, total blood loss (lit) decreased in the checklist group from 0.83 [1.23] to 0.78 [0.28] (p= 0.724), and total time (sec) from 186.51 [145.69] to 125.14 [101.46] (p=0.165). Clinical-based study: Participants performed statistically better with fewer number of errors per time with the application of the checklist compared to when no checklist was used respectively: Median [IQR] total number of errors 1.51 [0.80] vs 3.84 [1.42] (p=0.002), consequential errors 0.20 [0.12] vs 0.45 [0.42] (P=0.005), inconsequential errors 1.32 [0.75] vs 3.27 [1.48] (p=0.006) and total number of errors per number of instrument movements 0.16 [0.04] vs 0.29 [0.16] (p= 0.003). With the introduction of the checklist, the number of interventions by the trainer per time decreased from 2.79 [1.85] to 0.43 [1.208] (p=0.003) and the number of instrument movements per time decreased from 11.90 [5.34] to 10.38 [5.16] (p=0.04). Conclusions: We have developed standardised checklists to be applied during elective and emergency laparoscopic tasks. The performance based self-administered intra-procedural checklist had a significant accelerating effect on the acquisition of technical skills when applied by novices during a standardised laparoscopic lab-based routine task and improved the task performance during a simulated laparoscopic emergency scenario. The checklist enhanced the performance of surgical trainees and decreased the number of interventions of the trainer during laparoscopic cholecystectomy.

The effects of degree of sexual homogeneity, in groups of preschool children, on performance of a task were studied. Twenty four-year-old male children from the Utah State Child Development Laboratories served as subjects. Each subject performed the task of placing pegs in a pegboard during a sixty-second time interval; once in a group of opposite-sex peers; once in a group of same-sex peers; and once on a one-to-one basis with the author. The findings seemed to indicate that preschool children's rate of task performance is not influenced by the presence or absence of peers of the same-and opposite - sex. Differences between scores of subjects under each experimental condition were not significant.

Abstract Due to personal experience, I¡¦m interested in the impact of the leading style on the employees. When I was reading related research, I found that the leading style didn¡¦t show positive correlation on job performance when using the relation-oriented and job-oriented as the independent variable. Modern research support transactional leadership and transformational leadership. Therefore I took leading style as the independent variable, job performance as the dependent variable and the moderating variable is psychological contract. Descriptive statistics, reliability, factor-analysis, Pearson correlation and regression were chosen for data analysis and hypothesis testing. The result is shown as the following: 1. Transactional leadership and transformational leadership have positive impact on job performance. 1.1 Transactional leadership and transformational leadership have positive correlation impact and significant impact on task performance. 1.2 Transformational leadership has positive correlation impact and significant impact on contextual performance. 2. Psychological contract has different impact on job performance. 2.1 On task performance 2.1.1 Balanced contract has positive correlation impact and significant impact on task performance. 2.1.2 Relational contract has positive correlation impact and no significant impact on task performance. 2.1.3 Transactional contract has negative correlation impact and no significant impact on task performance. 2.2 On contextual impact 2.2.1 Balanced contract has positive correlation impact and significant impact on task performance. 2.2.2 Relational contract has positive correlation impact and no significant impact on task performance. 2.2.3 Transactional contract has negative correlation impact and no significant impact on task performance. 3.Psychological contract has positive correlation with leading style and job performance. 3.1Relational contract has negative moderating effect between transformational leadership and task performance. 3.2 Relational contract has negative moderating effect between transformational leadership and contextual performance.

For the past few years, virtual environments (VEs) have gained broad attention from both scholarly and practitioner communities. However, in spite of intense and widespread efforts, most VE-related research has focused on the technical aspects of applications, and the necessary theoretical framework to assess the quality of interfaces and designs has not yet been fully developed. This research, as a response to such challenges, concerns the usability of three-dimensional VEs. More specifically, this study aims to investigate the effects of wayfinding affordance design on users’ task performance and perceptual experience in 3D desktop VEs. For this purpose, four different wayfinding affordance conditions were set up: Fixed Detached Affordance Cues (FDAC) condition, Switchable Detached Affordance Cues (SDAC) condition, Portable Embedded Affordance Cues (PEAC) condition and Fixed Embedded Affordance Cues (FEAC) condition. Maps and directional cues were employed to implement wayfinding affordance. The results show that the design of wayfinding affordance has significant effects on users’ perceptual experience as well as their task performance. Task performance was significantly better where the maps and directional cues were provided independently from the VE interfaces (FDAC, SDAC). With regard to perceptual experience, the effect was significant only in simple environments. In these environments, the fixed and, therefore, stable interfaces (FEAC, FDAC) were found to provide a better sense of presence for users whereas the manipulative interfaces (PEAC, SDAC) offered a greater state of playfulness. The research findings also indicated that the design of 3D interfaces had a greater impact on non-expert users than on expert users. / text

Thesis (Ph. D.)--University of Alabama at Birmingham, 2007. / Title from first page of PDF file (viewed Oct. 31, 2007). Includes bibliographical references (p. 152-161).

Thesis (Ph. D.)--University of Washington, 1991. / Vita. Includes bibliographical references (leaves [91]-105).

Thesis--M.N. University of Washington, 1960.

Thesis--M.N. University of Washington, 1960.