# Virtual Humans in Museums and Cultural Heritage Sites
## 2 Methods and Context of the Study  
### Related Work  
[PERSON] and [PERSON] [3] provide a systematic review of digital human avatars 'Definitions, Uses, and Effects'; they note that digital human avatars' definitions vary to an extent and provide a section that outlines the convergences of existing definitions. In another section, they present the divergencies and, more specifically, the _similarities in conceptualization_ and _differences in conceptualization_. The authors examine digital humans' uses as well as the perceptions around them and their effects. The focus is on issues regarding their level of realism in terms of appearance and behaviour, and agency. The social categorization of avatars, e.g., in terms of racial characteristics and gender is presented, and issues of embodiment and self-expression through the choice of avatar are analysed. Moreover, the effect of avatars on human communication is investigated, addressing the emerging issues from multiple perspectives.  
Extensive surveys have been conducted concerning the presence of digital humans and avatars in cultural heritage Information and Communication Technologies (ICT) applications [4] and in virtual worlds [5]. They present the state-of-the-art concerning the use of digital human agents and avatars in virtual applications not only from the user's point of view, but also from the designer's. In [4], a table is provided that offers an overview of the main characteristics of digital human agent and avatar uses in cultural heritage-related applications, such as the types of technologies employed, the level of interactivity and the key implementation features. Furthermore, they offer a set of recommendations and good practices for the use of digital human agents and avatars in VR-based cultural heritage-related applications, as well as the strengths and weaknesses of existing applications. In [5], the survey focuses on the role of human-like characters as equivalents of real human users and as embodied agents driven by artificial intelligence. Information is provided concerning the crafting of virtual humans, and more specifically, in terms of appearance and the embodied agents. Furthermore, the authors focus on four application domains: environmental design, training, cultural heritage, and healthcare.  
In another paper [6], the first results of a survey on the use of digital humans (agents) and avatars in museums and places of cultural interest are presented. The research questions examined were related to (a) the technological characteristics of cultural heritage-related uses of digital humans/avatars and patterns that emerge, (b) what affects their potential for audience engagement, and (c) what directions may be suggested for future research based on the findings of this review.  
In this article, we reviewed all relevant publications and analysed the trends in technology, the online and onsite use of DHs, and their role as virtual guides or companions, as mediators of cultural content and as engaging facilitators. According to the virtuality continuum of [PERSON] and [PERSON], which provides an overview of the possibilities between the real environment and the virtual environment, virtual reality (VR) permits viewing, moving around and interacting in a fully immersive environment; augmented reality (AR) 'augments' the real environment by superimposing digital elements in the physical world; and mixed reality (MR) allows the superimposition of digital elements in the physical world and interaction with them. We focus less on the technical characteristics of these technologies and more on establishing the types of digital human, as well as the type of technology involved (i.e., AR or VR and the devices used), in relation to the types of museums/cultural heritage (CH) sites to identify emerging patterns and trends that could inform future research.