Human factors aspects of control room design: Guidelines and annotated bibliography

A human factors analysis of the workstation design for the Earth Radiation Budget Satellite mission operation room is discussed. The relevance of anthropometry, design rules, environmental design goals, and the social-psychological environment are discussed

Optimising computer displays for normal and visually impaired users

Computers have become ubiquitous in the modern world and most people spend several hours each day viewing computer displays. With the advent of LCD flat panel displays and the increase in graphical processing power, computer displays have rapidly evolved from barely legible text displays to the modern graphical user interface. Despite the improvement in the design and legibility of computer displays, complaints of visual discomfort are still surprisingly common amongst computer users. In many cases, the problems stem from poor workstation design, inappropriate working practices or uncorrected refractive errors or binocular vision anomalies. However, the fact that symptoms often persist when these factors have been addressed suggests that the design of computer displays may be suboptimal in a number of respects. There is a vast literature relating to the ergonomics of displays and yet there is still a lack of good quality data on the effects of key parameters on user efficiency and reading speed. In particular, there is very little information about the potential benefits of changing screen colours. The first part of this thesis describes a series of experiments designed to systematically examine the effects of contrast, font size, font style, letter spacing, contrast polarity, antialiasing and screen colour on the comfort and visual efficiency of users with normal vision. A series of tests were devised to assess user efficiency including search tasks and modified versions of the MNRead and Wilkins Rate of Reading tests. In general, user efficiency judged by performance in these tasks proved to be remarkably immune to changes in screen parameters and it is concluded that the default settings used on most displays is close to optimal. Many subjects subjectively preferred a background colour other than white although this preference was seldom rewarded by a measurable improvement in efficiency. However, changing the background colour did seem to reduce the prevalence of asthenopic symptoms. The second part of the thesis describes a series of investigations designed to examine the potential benefits of changing selected display parameters for individuals with Age Related Maculopathy, Primary Open Angle Glaucoma and Retinitis Pigmentosa. Of particular interest was the effect of changing screen colours given the anecdotal evidence that some patients with these conditions gain some benefit from coloured lenses. The relatively small number of subjects and the heterogeneous nature of the groups limited the scope of the conclusions that could be drawn from this study. However, it is clear that the visual performance of many visually-impaired individuals can be greatly enhanced by the correct selection of screen parameters, particularly font size, contrast and in some case, colour. A computer programme to assist in the optimisation of these parameters was developed as the final part of this work

Design of Work-Rest Schedules for VDT Operators.

The number of musculoskeletal and psychological discomforts is increasing as a result of continuing growth of VDT work. Although ergonomic improvements in workstation design can be applied, an effective work-rest schedule is an economical way to reduce these problems. The objective of this research was to determine an effective work-rest schedule for VDT operators. In addition to a discomfort questionnaire, performance and electromyography measurements from trapezius and flexor carpi radialis were used. Three different work-rest schedules were applied: 60-minute work/10-minute rest, 30-minute work/5-minute rest, and for the third schedule, the subjects received four breaks from VDT work each hour additional to a 14-minute break after two hours. Three of these breaks were 30 seconds in length and the fourth break was 3 minutes in length. The research also considered the effect of type of VDT task. Subjects were asked to enter alphanumeric data for data entry task and to solve addition/subtraction problems as mental task. The results indicated that effect of schedule was different on discomfort levels and performance of the subjects. Similarly, the type of task had different effects on discomfort, performance, and muscular tension levels. The 15/micro schedule was superior to the other schedules in terms of discomfort levels of the neck, back, and elbow/arm, eyestrain, speed, accuracy, and performance for both tasks. The lowest levels of trapezius muscle tension for data entry and flexor carpi radialis for mental tasks were resulted in the 15/micro schedule. The effect of the type of task was significantly different with 60/10 schedule on discomfort in shoulder and chest, bluffed vision, and headache; with 30/5 schedule on shoulder, chest and elbow/arm discomforts; and with 15/micro on discomforts in shoulder and hand/wrist. The schedule effect was different on data entry task for neck, lower back, elbow/arm discomforts and on mental task for headache. Mental task resulted in a higher psychological discomfort, lower physical discomfort, and lower performance than data entry task. The results of the study suggest that the 15/micro schedule is superior to the longer and infrequent rest break schedules considering upper extremity discomfort, eyestrain, speed, accuracy, and performance of the subjects

Visual search and VDUS

This wide-ranging study explored various parameters of visual search in relation to computer screen displays. Its ultimate goal was to help identify factors which could result in improvements in commercially available displays within the 'real world’. Those improvements are generally reflected in suggestions for enhancing efficiency of locatabolity of information through an acknowledgement of the visual and cognitive factors involved. The thesis commenced by introducing an ergonomics approach to the presentation of information on VDUs. Memory load and attention were discussed. In the second chapter, literature on general and theoretical aspects of visual search (with particular regard for VDUs) was reviewed. As an experimental starting point, three studies were conducted involving locating a target within arrays of varying configurations. A model concerning visual lobes was proposed. Two text-editing studies were then detailed showing superior user performances where conspicuity and the potential for peripheral vision are enhanced. Relevant eye movement data was combined with a keystroke analysis derived from an automated protocol analyser. Results of a further search task showed icons to be more quickly located within an array than textual material. Precise scan paths were then recorded and analyses suggested greater systematicity of search strategies for complex items. This led on to a relatively 'pure' search study involving materials of varying spatial frequencies. Results were discussed in terms of verbal material generally being of higher spatial frequencies and how the ease of resolution and greater cues available in peripheral vision can result in items being accessed more directly. In the final (relatively applied) study, differences in eye movement indices were found across various fonts used. One main conclusion was that eye movement monitoring was a valuable technique within the visual search/VDU research area in illuminating precise details of performance which otherwise, at best, could only be inferred

Engineering data compendium. Human perception and performance, volume 3

The concept underlying the Engineering Data Compendium was the product of a research and development program (Integrated Perceptual Information for Designers project) aimed at facilitating the application of basic research findings in human performance to the design of military crew systems. The principal objective was to develop a workable strategy for: (1) identifying and distilling information of potential value to system design from existing research literature, and (2) presenting this technical information in a way that would aid its accessibility, interpretability, and applicability by system designers. The present four volumes of the Engineering Data Compendium represent the first implementation of this strategy. This is Volume 3, containing sections on Human Language Processing, Operator Motion Control, Effects of Environmental Stressors, Display Interfaces, and Control Interfaces (Real/Virtual)

Analysing formal visual elements of corporate logotypes using computational aesthetics

The marketing mix contains a significant proportion of elements that derive their appeal and effectiveness from visuals. This thesis proposes the application of quantitative measures from the literature on computational aesthetics to evaluate and study the formal characteristics of corporate visuals in the form of logotypes (logos). It is argued that the proposed approach has a number of advantages in terms of efficiency, consistency and accuracy over existing approaches in marketing that rely on subjective assessments. The proposed approach is grounded on a critical review of a diverse literature that encompasses Marketing, Art History and Philosophy, and, Visual Science and Psychology. The computational aesthetic measures are framed within the construct of Henderson and Cote (1998) and van der Lans et al. (2009), in order to analyse brand logo design elements along with their effect on consumers. The thesis is underpinned by three empirical studies. The first study uses an extensive set of 107 computational aesthetic measures to quantify the design elements in a sample of 215 professionally designed logotypes drawn from the World Intellectual Property Organization Global Brand Database. The study uses for the first time an array of different measures for evaluating design elements related to colour that include hue, saturation, and colourfulness. The metrics capture both global design features of logos along with features related to visual segments. The metrics are linked to logo elaborateness, naturalness and harmony, using the theoretical framework of Henderson and Cote (1998). The results show that measures have a very diverse behaviour across metrics and typically follow highly non-normal distributions. Factor analysis indicates that the categorisation of the measurements in three factors is a reasonable representation of the data with some correspondence to the dimensions of elaborateness, naturalness and harmony. The second study demonstrates that the proposed computational aesthetic measures can be used to approximate the subjective evaluation of logo designs provided by experts.   Specifically, eight design elements for the sample of 215 logos, corresponding to harmony, elaborateness and naturalness, are evaluated by three experts. The results show for the first time that computational aesthetic measures related to colour along with other measures are useful in approximating subjective expert reviews. Unlike previous literature, this research combines both standard statistical methods for modelling and inference, along with more recent techniques from machine learning. Linear regression analysis suggests that the objective computational measures contain useful information for predicting proxy subjective expert reviews for logos. Model accuracy is substantially improved using neural network regression analysis based on Radial Basis Functions. The last study examines the role of consumer personality traits as moderators of the effect of perceived logo dynamism on consumer attitude towards the logo. One hundred and twenty-two participants were asked to evaluate elements of logo design (visual appearance, complexity, informativeness, familiarity, novelty, dynamism and engagement), their attitude towards the brand and their personality traits (sensation seeking, risk taking propensity, nostalgia and need for cognition). The estimates extracted were shown to vary significantly in terms of central tendency and dispersion and mostly follow non-normal distributions. Following Cian et al. (2014) the moderated mediator model by Preacher and Hayes (2008) is applied to test the suitability of personality traits as moderators of the effect of logo dynamism on attitudes towards the logo. The personality traits used as moderators are Need for Cognition and Risk-Taking Propensity, whereas Engagement was used as a Mediator. This is the first study to employ personality traits as moderators in such a study using this methodology. The results offer limited support of the role of personality traits as moderators in this relationship. Therefore, the study strengthens the case for the development of objective measures of visual characteristics. The working hypothesis in the thesis is that, with the help of computational aesthetic measures, marketing visuals such as corporate logos, can afford themselves to a consistent quantitative approach which can prove to be important for researchers and practitioners alike. By being able to group and measure the aesthetic differences, similarities and emerging patterns, access is gained to a new family of metrics, which can be applied to any type of logo across time, product, industry or culture

Human factors engineering checklists for application in the SAR process

This technical report was produced to assist the preparers and reviewers of the human factors portions of the SAR in completing their assigned tasks regarding analysis and/or review of completed analyses. The checklists, which are the main body of the report, and the subsequent tables, were developed to assist analysts in generating the needed analysis data to complete the human engineering analysis for the SAR. The technical report provides a series of 19 human factors engineering (HFE) checklists which support the safety analyses of the US Department of Energy`s (DOE) reactor and nonreactor facilities and activities. The results generated using these checklists and in the preparation of the concluding analyses provide the technical basis for preparing the human factors chapter, and subsequent inputs to other chapters, required by DOE as a part of the safety analysis reports (SARs). This document is divided into four main sections. The first part explains the origin of the checklists, the sources utilized, and other information pertaining to the purpose and scope of the report. The second part, subdivided into 19 sections, is the checklists themselves. The third section is the glossary which defines terms that could either be unfamiliar or have specific meanings within the context of these checklists. The final section is the subject index in which the glossary terms are referenced back to the specific checklist and page the term is encountered