# X-Reality Museums: Unifying the Virtual and Real World Towards Realistic Virtual Museums
## 3 A Conceptual Architecture for Unifying XR Experiences for Realistic Virtual Museums
\begin{table}
\begin{tabular}{l l l} \hline \hline \multicolumn{3}{c}{**Natural Multimodal Interaction**} \\ \hline \multirow{3}{*}{Challenges} & \(\bullet\) & Fusion of multiple modalities into such a complex system. \\  & \(\bullet\) & Multi-modal interactions in crowded real-life settings and interconnected VR environments. \\  & \(\bullet\) & Natural language processing, taking into account the diversity of museum visitors \\ \hline \multirow{3}{*}{Future Directions} & \(\bullet\) & Employ adaptive multimodality to support natural input in a dynamically changing context of use. \\  & \(\bullet\) & Advance embodied conversational agents, by adopting a completely new mind-set in designing and \\ \cline{1-1}  & & developing conversational interfaces, that will also take into account the diversity of potential users. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: _Cont._Next, virtual agents have to be placed in the virtual environment, in order to substitute the physical exhibits. This is handled by the true mediated reality components. A prerequisite for delivering high quality experiences is the realistic reconstruction of 3D models, matching-and in certain cases extending-their physical counterparts. 3D models should ideally not only represent in a realistic manner the museum exhibits, but also attempt to deliver their original form in case of ruined artifacts (e.g., states with missing parts). Then, the virtual representations of physical artifacts are placed in the virtual environment, in a veritable manner, a task that requires realistic rendering and animations. Last, a unified experience requires context-sensitive natural interaction with multiple users, which involves processes that are responsible for perceiving and interpreting users' natural input commands, namely gestures and natural language. In this respect, a natural language processing knowledge base needs to be embedded in the system, while a corresponding process will undertake the task of identifying the received user commands. At the same time, a variety of input gestures should be supported, in accordance with the state of the art in the field, thus allowing users to build upon their experiences with other gestural interfaces and interact with the virtual environment easily and effectively. In parallel, an emotion detection process will be in charge of monitoring and detecting user emotions, so that the system can be further adapted to the user. All identified gestures, speech, and emotions should be taken into account by a context-sensitive interaction decision making process, responsible for determining how the virtual statue will respond, considering also other parameters, such as the number of users who actively interact with the virtual exhibit and of those who passively attend the ongoing interaction. The decisions made will impact the virtual agent's behavior, in terms of posture, gestures, exhibited emotions, as well as the information that will be delivered through multiple possible formats, including spoken dialogue output. The next section (Section 4) exemplifies the aforementioned conceptual architecture through an example in the form of a case study.