## 2 Ten Case Studies in Extended Realities for Cultural Heritage Preservation  
Ten CH VR/AR use case studies are reviewed to analyze the development, design, and evaluation practices of these proposed CH XR applications, focusing on identifying best practices and how HCD was used to achieve usability in the different scenarios of use. Each use case highlights a specific design and evaluation method, and describes how development plans were put together to address the specific scenarios of use the novel applications intend to deliver. The following CH XR use cases are being reviewed:  
1. Chilly Mo--This is a VR/AR app for toddlers introducing ancient civilizations like Persia through interactive storytelling and gamified cultural exploration. This is usable at home, in museums, or in schools and a great example of the Design Thinking/Design Doing process (empathize, define, ideate, prototype, and test). Additionally, it provides examples of a moodboard, a storyboard, persona descriptions (for a typical user and an atypical user), diagram of a Task Analysis, a Hierarchical Task Analysis, sketches as prototypes, and wire-frame (digital) drawings as prototypes for the proof-of-concept evaluations. 2. Cham Culture AR App--This is an AR app showcasing Cham ritual dances and musicians from stone reliefs, using QR cards for interactive storytelling in museums or educational settings. It is a great example of using a newly developed (Universal Design Principles (UDPs)) heuristic evaluation (HE) method for new technology (in this case, AR). The research was triangulated as follows: persona descriptions, (UDP) HE, and a System Usability Survey (SUS). The SUS is used to assess the attitude and opinions of potential new users about the new app. This use case has a video demo of the app prototype, available online. 3. Memories of Kellie--This is a desktop VR experience of Kellie Castle in Scotland, using an interactive narrative and atmospheric design to teach users about the site's layered history. It is a great example of empirical UK research into different emotions triggered by the design of the experience, based on a literature review to inform the hypothesis, a prototype design based on the hypothesis, and a questionnaire design and a test with representative end-users to get their feedback about the experienced emotions. 4. Fort Ontario AR Tour--This is an on-site AR-enhanced self-guided tour in a museum in upstate New York, allowing users to view historical imagery overlaid on physical locations using mobile devices. It is a great example of CW with representative end-users, and simultaneous observational data collection while the end-users do the CW in a real space, with the AR app on a mobile phone. The simultaneous collection of qualitative data (CW data and observational data) and quantitative data with a within-subject statistical DoE is useful; it allows for a rich, multifaceted (i.e., based on qualitative and qualitative data) analysis and deep understanding of both the user experience and measurable task improvement outcomes. A within-subjects design (where each participant experiences multiple versions or conditions) can more accurately attribute differences in user engagement, understanding, or emotional response to the experimental variables themselves rather than who the participants are. This is crucial when developing evaluation methods for cultural heritage XR, as it helps isolate what aspects of the design truly enhance learning, immersion, or cultural appreciation--insights that would be obscured if individual differences were not accounted for. 5. Hanging Gardens of Babylon--This is an AR and VR experience made with the Time Passport app, enabling users to explore a speculative reconstruction of the ancient Hanging Gardens from anywhere in the world. It is a great example of VR making it possible to do things that are not possible in the real world--in this case, visiting a cultural heritage site with artifacts that do not exist anymore in physical form.