It is challenging for a computer to comprehend dynamic characteristics and variables of a human user; however, conceptual modeling can serve as a language to describe these dynamic aspects. In this research, we aim to model the human user’s varying input and output modalities in human-computer interaction, making the human appear as part of the system architecture. This allows technologies to adapt to the user’s different input and output modalities. As a first step, we model a class diagram to depict a systemic view of interaction. Secondly, we formulated a state machine diagram to describe the behavior of the user and IT artifact in the context of accessible interaction. These models contribute to accessible interaction between humans and computers, where the computer either changes or adjusts its own input and output modalities so that the human can receive them and provide their own outputs according to their abilities.

Geert Hofstede famously labelled culture as the “software of the mind”, affecting how people cognitively process the world, and how organisations, communities and societies are structured. This lends to explain how culture influences the ways that people, perceive, use and experience technology design, and how within user experience design, cultural logic should be applied to develop user interfaces (UI). This study draws on Hofstede’s cultural dimension of ‘uncertainty avoidance’ (UA) to examine how UA, or the ways in which people within certain cultures cope with uncertainty, unknown and change, to examine the influence of culture on self-service technology (STT) UI design. The authors evaluate a sample of ten UIs from various STTs in Japan, a country of higher UA (N = 5), and Finland (N = 5) a country of lower UA. The results show that in higher UA cultures design of STT’s UI often rely on multimodal interaction, bright colours, and clear progress guidance via illustrations. However, we find also some contradictions in design solutions within the same cultures. It seems that instead of designers’ cultural identities playing a role, designers’ expertise in usability, company brand, and requirements by context affect how UI components are constructed. We discuss theoretical impacts of these manifestations of UI design on how they relate to accessibility and usability. As an implication to the practice, we propose a UI design assumption that embraces ‘Zero Uncertainty’, combining clear flow guidance, text and illustrations, with multimodal guidance and feedback.

Design principles are used to specify design knowledge and describe the aim of artefact instantiation. Accessibility research aims to create artefacts that can be used by all users. However, schemes for design principles lack the tools to define accessibility explicitly. This study proposes extensions to scheme design principles for accessibility-related design science research. We draw accessibility domain-specific characteristics from the literature to include accessibility in design principles for Human-Computer Interaction (HCI) instantiations. We extended the components of design principles with the following attributes: HCI Artefact Features; Contextual factors; Computer Input Modalities; Computer Output Media; Human Sensory Perception; Human Cognition; Human Functional Operations. We devised a checklist for researchers to follow the variations in accessibility. The extensions are intended to foster researchers to incorporate accessibility in producing a more accurate formulation of design principles.