Investigating the relationships between user capabilities and product demands for older and disabled users

This paper presents the results of a study that specifically looks at the relationships between measured user capabilities and product demands in a sample of older and disabled users. An empirical study was conducted with 19 users performing tasks with four consumer products (a clock-radio, a mobile phone, a blender and a vacuum cleaner). The sensory, cognitive and motor capabilities of each user were measured using objective capability tests. The study yielded a rich dataset comprising capability measures, product demands, outcome measures (task times and errors), and subjective ratings of difficulty. Scatter plots were produced showing quantified product demands on user capabilities, together with subjective ratings of difficulty. The results are analysed in terms of the strength of correlations observed taking into account the limitations of the study sample. Directions for future research are also outlined. © 2011 Springer-Verlag.

A survey on technology exposure and range of abilities of elderly and disabled users in India

This paper reports a survey on people with age-related and physical impairments in India. The survey evaluates functional parameters related to human computer interaction and reports subjective attitude and exposure of users towards technology. We found a significant cognitive decline in elderly users while their functional parameters are sufficient to use existing electronic devices. However young disabled users are found to be experienced with computer but could not have access to appropriate assistive devices, which would benefit them. Most users used desktop computers and mobile phone but none used tablet, smartphone or kiosks though they are keen to learn new technologies. Overall we hope that our results will be useful for HCI practitioners in developing countries. © 2013 Springer-Verlag Berlin Heidelberg.

Damage development in an armor ceramic under quasi-static indentation

The objective of the present study is to assess the capabilities of a recently developed mechanism-based model for inelastic deformation and damage in structural ceramics. In addition to conventional lattice plasticity, the model accounts for microcrack growth and coalescence as well as granular flow following comminution. The assessment is made through a coupled experimental/computational study of the indentation response of a commercial armor ceramic. The experiments include examinations of subsurface damage zones along with measurements of residual surface profiles and residual near-surface stresses. Extensive finite element computations are conducted in parallel. Comparisons between experiment and simulation indicate that the most discriminating metric in the assessment is the spatial extent of subsurface damage following indentation. Residual stresses provide additional validation. In contrast, surface profiles of indents are dictated largely by lattice plasticity and thus provide minimal additional insight into the inelastic deformation resulting from microcracking or granular flow. A satisfactory level of correlation is obtained using property values that are either measured directly or estimated from physically based arguments, without undue reliance on adjustable (nonphysical) parameters. © 2011 The American Ceramic Society.

Design for all: designing for the motion-impaired user

Designing for all requires the adaptation and modification of current design best practices to encompass a broader range of user capabilities. This is particularly the case in the design of the human-product interface. Product interfaces exist everywhere and when designing them, there is a very strong temptation to jump to prescribing a solution with only a cursory attempt to understand the nature of the problem. This is particularly the case when attempting to adapt existing designs, optimised for able-bodied users, for use by disabled users. However, such approaches have led to numerous products that are neither usable nor commercially successful. In order to develop a successful design approach it is necessary consider the fundamental structure of the design process being applied. A three stage design process development strategy which includes problem definition, solution development and solution evaluation, should be adopted. This paper describes the development of a new design approach based on the application of usability heuristics to the design of interfaces. This is illustrated by reference to a particular case study of the re-design of a computer interface for controlling an assistive device.

Dissolving and aligning carbon nanotubes in thermotropic liquid crystals.

It has been widely recognized that the combination of carbon nanotubes (CNTs) and low molar mass thermotropic liquid crystals (tLCs) not only provides a useful way to align CNTs, but also dramatically enhances the tLC performance especially in the liquid crystal display technology. Such CNT-tLC nanocomposites have ignited hopes to address many stubborn problems within the field, such as low contrast, slow response, and narrow view angle. However, this material development has been limited by the poor solubility of CNTs in tLCs. Here, we describe an effective strategy to solve the problem. Prior to integrating with tLCs, pristine CNTs are physically "coated" by a liquid crystalline polymer (LCP) which is compatible with tLCs. The homogeneous CNT-tLC composite obtained in this way is stable for over 6 months, and the concentration of CNTs in tLCs can reach 1 wt %. We further demonstrate the alignment of CNTs at high CNT concentrations by an electric field with a theory to model the impedance response of the CNT-tLC mixture.

The calculation of acoustic shielding of engine noise by the Silent Aircraft Airframe

The Silent Aircraft airframe has a flying wing design with a large wing planform and a propulsion system embedded in the rear of the airframe with intake on the upper surface of the wing. In the present paper, boundary element calculations are presented to evaluate acoustic shielding at low frequencies. Besides the three-dimensional geometry of the Silent Aircraft airframe, a few two-dimensional problems are considered that provide some physical insight into the shielding calculations. Mean flow refraction effects due to forward flight motion are accounted for by a simple time transformation that decouples the mean-flow and acoustic-field calculations. It is shown that significant amount of shielding can be obtained in the shadow region where there is no direct line of sight between the source and observer. The boundary element solutions are restricted to low frequencies. We have used a simple physically-based model to extend the solution to higher frequencies. Based on this model, using a monopole acoustic source, we predict at least an 18 dBA reduction in the overall sound pressure level of forward-propagating fan noise because of shielding.