Stephen V. Metz

A Methodology for the Evaluation of Real-Time Speech Digitization

Real-time speech digitizing technologies underlie such modern communications products as voice store and forward systems and digital PBXs. Among the human factors design issues associated with this technology, three of particular importance can be identified: i) speaker identifiability, ii) acceptability of speech quality, and iii) speech intelligibility. An experimental method for addressing issues of identifiability and intelligibility was developed and used to compare a commercial speech digitizing device with a standard toll quality telephone channel. It was found that the identifiability and acceptability of the telephone was slightly superior to the digitized speech. Additionally, results on an MRT showed intelligibility scores somewhat below optimal.

Rapid-Software for Prototyping User Interfaces

The present paper describes 1) the operation of a software tool for interface prototyping–RAPID–that is designed for software designers and human engineering specialists to use in support of design iteration and experimentation and 2) an application of this prototyping tool in the development of consumer products. RAPID simulates the appearance and function of small control panels including commonly-used displays and controls using the Smalltalk-80TM computing environment. The experience of using the design tool in a product development effort has provided a means of evaluating the success of this approach for supporting the product development cycle and improving the quality of the human-machine interface.

Small Rotary Controls: Limitations for People with Arthritis:

Improving access for persons with arthritis requires consideration of their basic abilities. This paper focuses on the design of knobs and how variations in key design factors can either create barriers or provide access for persons with arthritis. This information will provide input for human factor design guidelines that will promote universal access in home and workplace. Subjects for this study included 80 individuals with diagnosed rheumatoid or osteoarthritis, with an equal number in a control group. The test apparatus included a set of round knobs mounted on an apparatus for measuring static torque. We tested knobs of two diameters and varying surfaces and profiles. A pinch strength test was also conducted. Results showed individuals with arthritis applied significantly less torque to all control knobs than did control subjects and had relatively more difficulty with the larger knobs. The pinch test results correlated well for each subject with their applied torque on the rotary controls.

A User Interface Design Concept for Visualization of Multidimensional Process Models

We describe a user interface design concept for the interactive visualization of multidimensional industrial process models. Key features of the design include: a matrix layout of 3-D and 2-D graphical plots, an interaction area for visualizing integral relationships and selecting context for viewing individual x-y functions, and a reference area extending throughout the matrix for maintaining focus on desirable values of product quality. These features are motivated by task-specific needs to develop conceptual models of the physical processes used in making products. Conceptual models enable process engineers to determine the optimal operating ranges for controllable process parameters.