M. S.

This thesis examined the effects of luminance contrast, raster modulation, and ambient illumination on readability and image quality of text presented on a CRT display. Participants read a Tinker Speed of Reading text passage on the monitor and then responded when they found the out-of-context word in the passage. Correct responses and response times were recorded. Participants also rated the image quality of the monitor by selecting a number between one (worst imaginable) and nine (best imaginable). An ANOVA revealed that luminance contrast significantly affected errors. It is suggested that luminance contrasts of 7:1 be used to maintain low error rates. None of the independent variables affected the time required to read the Tinker passages. However, luminance contrast, raster modulation, and illumination significantly affected the subjective quality ratings. Participants rated the 3:1 luminance contrast, the 1.2 RAR, and the 1000 lux ambient illumination conditions as possessing the lowest image quality. From this research, it can be concluded that 7:1 is the preferred contrast ratio. This conclusion is based upon the findings that the 3:1 and 7:1 luminance contrast conditions produced the fewest errors and the 5:1 and 7:1 luminance contrast conditions produced the highest subjective image quality ratings. This recommendation holds over a RAR range of 0.8 to 1.2 and an ambient illumination range of 10 to 100 lux. High illumination levels would require special attention due to the low image quality ratings for the 7:1/1000 lux interaction. / Master of Science

M.S.

This dissertation investigated the effects of age on performance and image quality rating while varying screen surface treatment, ambient lighting, and character resolution. Five age groups were included, ranging from 18 to 69 years of age. The study used a factorial design to vary seven surface treatments which either reduced glare, enhanced contrast, or both; three lighting conditions, dark, diffuse, and specular; and two character resolutions, high and low, subtending visual angles of 16.1 arcmin. and 32.2 arcmin. respectively. Performance was measured using both a speed of reading task and a search task. In addition, subjects rated the image quality of displayed characters within each filter, lighting, resolution condition using a list of nine adjectives. Results showed performance times to increase with age. The older age groups (40-49, 50-59, 60-69) performed better with the quarterwave filter, which enhanced contrast and reduced glare, and most poorly with the filters with the harshest etch (Gloss25) and the lowest transmission (31%). Performance was significantly slower for specular and dark lighting. A finding consistent with previous research indicated that extremely high luminance contrast degrades performance with low room illumination. Finally, for all conditions in which resolution was a factor performance was fastest and ratings were highest with the low resolution characters. / Ph. D.

Information processing has altered the structure of the traditional office. Typewriters are no longer a necessity to prepare written business communication. As a result of a metamorphosis from manual data manipulation to electronic data processing, microcomputers and their related peripheral equipment are becoming the key link in the information system. Increased usage of microcomputers and word processing software has been linked to decreased proficiency in detecting errors and in turn to decreased office productivity. Thus a number of questions arise including: Is it better to proofread from a hardcopy or a softcopy document? Does the color and contrast configuration of a video display terminal affect the operator's ability to proofread? The effect on the operator's ability to accurately detect errors in keyboarded text from different media has not been previously determined. This study was therefore completed to ascertain if a difference does exist. Seventy-two individuals enrolled in four word processing classes at a western North Carolina community college comprised the individuals participating in this study. Participants completed a demographic questionnaire, a pretest instrument, and one of four error detection instruments. The error detection instruments were presented in either a hardcopy or softcopy format. The softcopy format consisted of three video display terminal configurations. Analyses of covariance with pretest scores used as the covariate were used to compare the quantity and types of errors detected by error detection environment configurations. Based on the findings from the analyses of data the following conclusions were derived. 1. Postsecondary word processing students have difficulty in finding errors in hardcopy and softcopy documents. 2. Postsecondary word processing students' abilities to detect errors in keyboarded text were not affected by the error detection environment–hardcopy or softcopy–during a ten-minute error detection process. Therefore, the printing of a hardcopy of keyboarded text when detecting errors for a short time period is not necessary. 3. Postsecondary word processing students' abilities to detect errors in keyboarded text were not affected by the video display terminal configurations examined in this study. A video display terminal’s color configuration is not a factor in the error detecting process for a short time period-ten minutes. Therefore, the color configuration of a video display terminal should not be a major consideration when purchasing new video display terminals for instructional use. 4. As the spelling Verification feature of word processing software does not detect all types of errors, instruction is needed in detecting errors that cannot be detected by the software’s spelling Verification feature. / Ed. D.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Lau Tsz Yam. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 91-94). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Characterization of Colour Deficiency --- p.7 / Chapter 2.1 --- Mechanism of colour vision --- p.7 / Chapter 2.2 --- Quantitative specification of colour --- p.10 / Chapter 2.3 --- Discrimination ellipses --- p.17 / Chapter 2.4 --- Colour perception of colour deficient people --- p.22 / Chapter 2.5 --- Luminance match of colour deficient people --- p.32 / Chapter 2.6 --- Diagnosis of colour deficiency --- p.32 / Chapter 2.7 --- Dichromat simulation algorithm --- p.35 / Chapter 3 --- Monocular Compensation --- p.37 / Chapter 3.1 --- Principle --- p.37 / Chapter 3.2 --- Potential problems without monocular compensation --- p.39 / Chapter 3.3 --- Existing monocular compensation implementations --- p.45 / Chapter 3.4 --- Compensation algorithm for monocular compensation --- p.47 / Chapter 4 --- Stereo Visual Display Unit - Monocular Compensation --- p.48 / Chapter 4.1 --- Gamut-based palette compression --- p.49 / Chapter 4.2 --- Compensation level --- p.56 / Chapter 4.3 --- Realizing transformed chromaticities --- p.59 / Chapter 5 --- Evaluation --- p.64 / Chapter 5.1 --- Extensiveness of compensation --- p.65 / Chapter 5.2 --- Combination of discriminations from the two eyes --- p.68 / Chapter 5.3 --- Discrimination improvement and visual comfort --- p.72 / Chapter 6 --- Conclusion and Future Works --- p.82 / Chapter A --- Raw Data of Experiment 53 --- p.85 / Bibliography --- p.91

This study focuses on developing a new approach to seated work positions. It was conducted on 67 office workers who use the Video Display Terminal (VDT) as a major function of their working day. Muscle tension was measured by surface electromyography when subjects were asked to adopt four selected working postures. Pain was measured before and after ergonomic intervention on the Nordic scale, which was modified for this study. Performance was measured on timed typing tests. A psychosocial questionnaire was used to determine influences of job demands, and a diagnostic assessment was performed to determine symptoms and pre-existing musculoskeletal conditions. Furniture was used to place subjects in desired positions during the clinical testing sessions and the extended intervention period. The chair seat pan was adjusted to a forward tilt to promote a lordotic curve of the low back, resulting in an erect upper body and upright head position. The desk and keyboard were adjusted to the proper height for each worker. A neutral wrist position was obtained by lowering and tilting the keyboard away from the user. Results revealed muscle tension scores in the upper trapezius and forearm extensors were significantly reduced when the workers were placed with the head in a midline position, with forward-tilting seating and with use of a negative sloping keyboard tray. Subjects reported low pain scores at pretest so no changes were noted after intervention. Loss of control over job elements, lack of job satisfaction, and fear of job loss were related to an increase in muscle tension. Only fear of job loss correlated to increased pain levels. There was no relationship between any of the job demand factors and performance.

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 174-179). Also available via the Internet

Thesis (Ph. D.)--University of California, San Diego, 2003. / Vita. Includes bibliographical references (leaves 371-389).