# Comparative Analysis of Usability and Accessibility of Kiosks for People with Disabilities
## 2 Literature Review  
### Accessibility and Usability  
Many studies have conducted intensive literature reviews to compare and analyze the concepts of accessibility and usability. [PERSON] et al. [31] defined accessibility as a subset of usability that only affects people with disabilities while defining usability as a concept that affects both people with and without disabilities. On the other hand, [PERSON] and [PERSON] [32] subdivided the concepts of pure accessibility, pure usability, and universal usability, targeting both people with and without disabilities. Pure accessibility concerns people with disabilities, pure usability only concerns those without disabilities, and universal usability concerns both those with and without disabilities. In their study, the types of problems experienced by both people without disabilities and visually-impaired people were identified on a website, and the relational characteristics between these problems were identified. Accordingly, [PERSON] et al. derived problems related to universal usability for both people with and without disabilities, which contrasts with the concept in the study. The meaning of usability, UX, and accessibility and the relationship between these concepts have been investigated and analyzed [33]. Accessibility is defined as a concept that does not include affective elements such as fun and enjoyment, and it is closer in meaning to usability than it is to UX. When people with disabilities interact with a device, their UX includes many emotional elements as well as usability [34]; thus, it is necessary to distinguish UX from accessibility. [PERSON], [PERSON], and [PERSON] [35] investigated the relationship between UX properties and web accessibility. They measured the accessibility in terms of that perceived by the participants and that specified in the guidelines. The results showed that the web accessibility perceived by the participant had a significant correlation with 27 out of 35 UX attributes. [PERSON] and [PERSON] [23] introduced the concepts of usability, accessibility, and UX as criteria for developers to evaluate the E-system. Despite the clear consensus standard, the relationship between accessibility and usability was still unclear. In this study, the difficulties experienced by people with disabilities and by the elderly when using the E-system were defined as accessibility issues, and the difficulties experienced by people with disabilities and younger users were defined as usability issues.  
In previous studies, the usability of a product/service for a person with a disability was defined as accessibility [31; 32], and accessibility was mainly studied as a sub-item of usability [36]. However, as discussed in the existing literature [32], the concept of universal usability exists, and people with disabilities also perceive usability when using products/services; therefore, the concepts of accessibility and usability need to be separately defined with respect to the needs of people with disabilities. In this study, the concepts of accessibility and usability for people with disabilities were defined as follows. Accessibility indicates the degree of ease for people with disabilities to access the main functions of devices/services [37] and should be considered essential when using devices/services.  
Usability for people with visual impairments can also be considered \"usable accessibility\" [38], which indicates how effectively and efficiently a device/service can be used [32]. It mainly includes considerations regarding the psychological discomfort or convenience of a person in using the device. Based on these conceptual characteristics, accessibility should be prioritized over usability for users with disabilities. Users with disabilities cannot use a device/service regardless of the level of usability if accessibility has not been guaranteed.