## 5 State of the Art in Conversational AI Platforms  
In the following paragraphs a review of the most well-known and widely used conversational AI platforms is presented, along with an evaluation based on the AHP method. The aim of this evaluation is to identify a platform that utilizes KGs and provide features that promote the distributed collaboration of multiple chatbots in a museum.  
Based on our previous research, four categories of AI chatbot platforms were identified: (a) no-coding task-oriented platforms, (b) conversation-oriented platforms, (c) conversational AI platforms backed by tech giants, and (d) conversational AI platforms backed by startup companies [95]. More specifically:  
1. The no-coding platforms are simple task-oriented platforms that do not integrate advanced AI (NLU/ML) capabilities. Examples of the famous platforms in this category are Chatfuel [96], Octane.ai [97] and Motion.ai [98].
2. The conversation-oriented platforms are not designed to serve a specific task but to develop chatbots that follow a specific conversation with humans (or software agents), with no use of advanced AI techniques. An example of the most famous platforms in this category is PandoraBots [99].
3. The conversational AI platforms backed by tech giants are the most advanced platforms that are using advanced AI techniques (NLU and ML) and integrate large knowledge sources such as webpages, ontologies, KGs and others. Examples of the most famous platforms in this category are Google's Dialogflow [100], Facebook's Wit.Ai [101], IBM's Watson Assistant [102], Microsoft's Bot Framework [103] and Amazon's Lex [104].  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Chatbot** & **Conversational Skills** & **Advanced AI Methods** & **KGs Support** & **Active** \\ \hline National Art Museum of the  Republic of Belarus & No & No & No & No \\ \hline Anne Frank House in  Amsterdam & No & No & No & No \\ \hline [PERSON]’s Chatbot & No & No & No & Yes \\ \hline Martr museum bot & No & No & No & Yes \\ \hline House Museum of Milan & No & No & No & Yes \\ \hline Chat Cat bot & Rule based conversations & Limited NLU training & No & No \\ \hline Maximo the Titanosaur  Webpage bot & Yes & Fully trained, NLU and & No & Yes \\ \hline [PERSON] chatbot app & Yes, not fully developed & Limited NLU training & No & Yes \\ \hline [PERSON] Bot & Available but not used & Available but not used & No & Yes \\ \hline IRIS at Museum of Tomorrow & Yes & NLU and ML & \begin{tabular}{c} Yes, on IBM Bluemix cloud \\ platform-Graph visualization \\ \end{tabular} & \begin{tabular}{c} Yes \\ onsite \\ \end{tabular} \\ \hline Dialogue with the artwork  chatbot (Buenos Aires) & Yes & NLU and ML & No & No \\ \hline Voice of Art Chatbot (Pinaccoteca of São Paulo) & Yes & NLU and ML & \begin{tabular}{c} Yes, on IBM Bluemix cloud \\ platform \\ \end{tabular} & Not defined \\ \hline Ask Mona Studio chatbots & \begin{tabular}{c} No \\ (Only predefined answers) \\ \end{tabular} & No & No & Yes \\ \hline EU Culture Chatbot project & Available but not used & Available but not used & Yes–Dgraph–not fully developed & \
\begin{tabular}{c} Yes, a \\ demo \\ \end{tabular} \\ \hline
\begin{tabular}{c} Cartier Foundation for \\ Contemporary Art bot \\ \end{tabular} & Yes, but limited & Available but not used & No & Yes \\ \hline Akron Art Museum bot & No & No & No & Yes \\ \hline \hline \end{tabular}
\end{table}
Table 2: Selected Museum chatbots’ characteristics (II).  
4. The conversational AI platforms backed by startup companies are also platforms that use advance AI techniques and can integrate large sources of knowledge. The most famous platforms in this category are Rasa Framework [105], Botpress [106] and OpenDialog [107].  
In the following paragraphs a description of the ten most famous (well-known and widely used) platforms of the last two categories, i.e., (c) and (d) is provided. The museum chatbots that are presented in this paper were developed with one of these platforms.