Proceedings of the Human Factors and Ergonomics Society Annual Meeting

We have developed design rules for diagrammatic instructions for initial setup, basic maintenance and troubleshooting (i.e., clearing paper jams) tasks. The study reported here evaluated these rules. Four groups of novice users cleared paper jams in a laser printer using one of four different diagrammatic instructions. Diagrams presented to the first two groups all followed the rules but differed in the number of actions per diagram (one verses 3-4). The remaining groups' instructions contained diagrams that violated one or more rules. Instructions that followed the diagram design rules resulted in no errors. Diagrams that prevented users from correctly identifying the location of a subtask resulted in the most severe errors. Other rule violations resulted in fewer errors of lesser severity so if users were shown the general location of the problem they could perform a subtask. Times to complete each subtask were similar unless the location rule was violated.

This paper describes a cognitive usability analysis of a home stereo as well as an experiment that tests the predictions borne out of that analysis using the RAFIV method of cognitive usability analysis (Sherry, Polson, Fennell, & Feary, 2002). At the heart of this method is a five-stage model that describes a user's cognitive steps as they perform a task. This model provides a framework for analyzing an interface by asking whether or not each stage can be accomplished purely through label-following. The results suggest that the RAFIV technique can be used to predict which tasks might prove difficult for users. Furthermore, it suggests that the number of recall steps within a task can play a negative role in a user's ability to complete that task.

The Federal Food, Drug, and Cosmetic Act broadly regulates the content of Consumer-Directed Broadcast Advertisements (CDBA). Information processing capabilities of average consumers may be exceeded by broadcast advertisements that present too much information. The purpose of this study was to examine usability problems encountered by viewers of broadcast advertisements and to isolate “best practices” that facilitated information transfer. Two age groups, older and younger viewers, evaluated different prescription drug advertisements based on usability and provided verbal reports to open-ended questions in a focus group. Avoiding information overload, eliminating or reducing distracting stimuli, and slowing the rate at which information is presented are important usability guidelines that should be applied to content specifications.

A population often overlooked in the design of cellular phones is people with cognitive disabilities. This study evaluated the ability of persons with moderate to severe cognitive impairments to use mainstream cellular phones programmed with experimental interface features that allowed operation with minimum cognitive ability. Two modes were tested. The first allowed an individual to place calls by simply opening a flip phone. The second displayed four pictures on the touchscreen and allowed a call to be made by touching one of the pictures. Sixteen individuals with Mini-Mental State Examination (MMSE) scores from 6 to 19 participated. There was a 100% success rate using the flip mode in both Instruction and Carryover conditions and a 100% success rate in Instruction and 81.3% success in Carryover for the picture mode. This was compared to standard ‘touchtone’ dialing mode success rate of 12.5% in the Instruction condition and 6.3% in Carryover condition.

Although the small size of handheld computers increases portability and mobility, it causes difficulty reading information displayed on a small screen. In an attempt to improve text readability of handheld computers, this study investigated the effects of screen orientation and margin on reading speed, comprehension, and subjective ease of reading with a handheld computer. A 2×2 within-subject factorial design was conducted with 16 participants reading text from a PDA. In addition, users' preference for the two factors and their experiences with reading with the PDA were elicited in a post-experiment questionnaire. Finally, usability problems encountered were discussed in the interview. The results of this study indicated that neither screen orientation nor margin had a significant influence on reading performance. No prevailing preferences for screen orientation and margin were found. Invaluable qualitative information regarding usability problems was identified, which, in turn, supports several recommendations to improve reading from small screens of handheld computers.

A group of digital human models with various sizes which properly represents a population under consideration is needed in the design process of an ergonomic product in virtual environment. The present study proposes a two-step method which produces a representative group of human models in terms of stature and weight. The proposed method first generates a designated number of pairs of stature and weight within an accommodation range from the bivariate normal distribution of stature and weight of the target population. Then, from each pair of stature and weight, the method determines the sizes of body segments by using ‘hierarchical’ regression models and corresponding prediction distributions of individual values. The suggested method was applied to the 1988 US Army anthropometric survey data and implemented to a web-based system which generates a representative group of human models for the following parameters: nationality, gender, accommodation percentage, and number of human models.

Ten woven fabrics for lady's blouse including natural silk and synthetic ones were selected and the objective sound characteristics including level pressure of total sound (LPT_oct), level range (ΔL_oct), frequency difference (Δf_oct), and variance of levels (VL_oct) were obtained from one-third octave band spectra of each rubbing sound of the fabrics. Consumers' subjective sensation (softness, loudness, sharpness, clearness, roughness, highness, and pleasantness) was rated by free modulus magnitude estimation (FMME). Silk and synthetic fabrics showed similar shapes of octave band spectra. Silk fabrics were found as sounding much more pleasant than synthetic ones. In relationship between objective measurements and subjective sensation, subjective clearness for silk fabrics was explained significantly by ΔL_oct and VL_oct, whereas subjective softness was significantly described by the parameters for synthetic ones.

Most regression models of anthropometric variables use stature and/or weight as regressors; however, these ‘flat’ regression models result in large errors for anthropometric variables having low correlations with the regressors. For better accuracy in estimating anthropometric variables, this study proposed a method to estimate anthropometric variables in a hierarchical manner based on the geometric and statistical relationships among the variables. By applying the proposed approach to 60 anthropometric variables selected for the design of an occupant package layout in a passenger car, hierarchical estimation structures were constructed and then based on the estimation structures hierarchical regression models were developed with the 1988 US Army anthropometric survey data. The hierarchical regression models were compared with the corresponding flat regression models in terms of adjusted R² and SE, resulting in on average a 55% increase in adjusted R² and a 31% decrease in SE when compared to the corresponding flat models.

An analytical approach to the user-centered design of a wall clock utilizing an engineering model, a cost model, and a marketing model is demonstrated. An engineering model is used to optimize the design with respect to material use and functionality. A cost model considers fixed and variable costs for the producer. The marketing model utilizes preference data collected from a discrete choice conjoint analysis survey and analyzed with the logit model to represent user preferences quantitatively in the form of demand curves. The survey explores tradeoffs among four product characteristics (face diameter, frame width, font style, and font size) and price. The engineering, cost, and marketing models are integrated and the design is optimized to maximize profit by considering tradeoffs among design requirements, cost, price, and product characteristics. Cluster analysis defines three market segments within the survey preference data and solutions are optimized for each of the three market segments.

Touch/feel quality of interior material is a critical element of customer's perception of overall product quality. Manufactures are increasingly interested in the affective evaluation as the perception of quality is heavily related to customer's feeling toward the product. Surface material quality is characterized by complex touch-feel sensations. In this study, 30 participants rated their affective reactions (how pleasant I feel) to surface materials of 30 different automobile interiors. Four categories of the material characteristics are used in the evaluation; crash pad plastic, steering wheel plastic, wood grain and metal grain. Consistent with previous research, it was found that both the visual quality and touch/feel quality influenced customer's perception of the material quality. Variables related to touch/feel quality is structured as ‘an affective quality checklist’ for automobile interiors to be used by a trim engineering team of an automobile manufacturer.

Adjustable stops are available on many weightlifting machines, and have the potential to prevent some injuries that occur during exercise. The safety benefit depends in large part on whether and how the stops are used. Unobtrusive observations at health clubs indicate that most patrons fail to use the adjustable stops. Advantages and disadvantages of several approaches to injury prevention are considered.

This paper describes how to design an adjustable stool for height based on Human Design Technology (HDT). HDT is a Human-centered Design/product development method of visualizing user requirements, which are extracted by 3P (three-point) task analysis and other tools, via a database of seventy design items and a structured concept. Namely a structured concept is constructed based on user requirements and make them visualized using seventy design items. The seventy design items of HDT are classified into the eight large groups: 1) User interface design (twenty-nine design items), 2) UD (nine design items), 3) Kansei (sensitivity) design (nine design items), 4) Product liability design (six design items), 5) Ecological design (five design items), 6) Robust design (five design items), 7) Maintenance design (two design items), and 8) other (human-machine interface design) (five design items). An adjustable stool for height was designed based on HDT.

The importance of usability has been increasingly recognized due to the enlargement, convergence and complication of product functions. Usability is becoming a key factor in determining the success of a product, so that users can understand how to operate it and benefit from the functionality it offers. In this study, usability evaluation plan and procedures for mobile products are given, based on the usability evaluation framework of everyday products that is under debate currently in the Europe. Suggested framework can be used as a tool for enhancing the usability of mobile products from the initial product development stage to the product review stage

Salespeople (selling dryers, cell phones, recliners, or jewelry) in 25 stores were asked to recommend products they believed to be easy to use. They were also asked which products or features were most likely to be helpful to customers with specific physical, cognitive, or sensory limitations. There was little consensus across salespeople selling the same product. There were surprising omissions and some examples of incorrect claims. Further, salespeople largely ignored (or were unaware of) design features that enhance sensory and cognitive usability. The majority of claims dealt with product features that purportedly reduce physical strain.

The purpose of this research is to minimize the negative effects and maximize the benefits of the introduction of new technology to consumers. This paper examines the effect of user processing and product change on the acceptance of product upgrades. User processing is defined as the type of cognitive processing a user employs to complete a task, and is identified as either controlled or automated. Three types of product changes are examined: omission (removing a task step), commission (adding a task step), and sequence (changing the order of task steps). Both the short term and long term effects of these changes on user performance are examined. The platform utilized was an inventory management computer program. Task completion time was collected from 31 subjects. The results indicate a difference in user performance based on processing type: subjects adapted to changes in the program more readily when using controlled processing as opposed to automated processing. Users have difficulty recovering from a task change when they are using automated processing. When they are using controlled processing, the change is more readily accepted. The variability of their performance was greater when using controlled processing. Task changes were most readily adapted to when the change was that of sequence. Changes of omission and commission caused a greater negative effect on the subjects' performance.

Mass customization aims at satisfying individual customers, who are given an opportunity to select among several design features and order a unique product. In this experiment four web sites were created where users could specify the design features of a mobile phone. Two web sites were designed to build a mobile phone from scratch: One used a rating agent of design features, and the other had no rating agent. The two other web sites used an existing phone as a basis for design - one used a rating agent and the other had no rating agent. Forty test persons participated in an experiment to evaluate the web sites. Half of them were male and half of them female. The use of the rating agent produced more consistent and better design. The model for mass customization — whether building from scratch or modifying an existing phone — had no impact on the results. There were no differences in results between males and females.

The Product Design Technical Group (formerly the Consumer Product Technical Group) sponsored the third annual user-centered product design competition emphasizing product design and the methods used to specify and achieve the design. Emphasis was placed on innovative and user-centered approaches to Human Factors and Industrial Design.