# Toward a Symbolic AI Approach to the WHO/ACSM Physical Activity & Sedentary Behavior Guidelines
## 2 Materials and Methods
### Symbolic AI Approach: From Analysis to Design
#### 2.3.3 Domain and Top-Level Ontology Analysis  
We aim at understanding what already exists in the literature, which can help us to model the entities of our domain and, at the same time, to identify the gaps, Figure 1, see step labeled as (c)). To this end, we compared the most relevant domain ontologies, including SMASH (Semantic Mining of Activity, Social, and Health data) ([[https://biopr.otal.bioontology.org/ontologies/SMASHHYSICAL](https://biopr.otal.bioontology.org/ontologies/SMASHHYSICAL)]([https://biopr.otal.bioontology.org/ontologies/SMASHHYSICAL](https://biopr.otal.bioontology.org/ontologies/SMASHHYSICAL)), accessed on 28 November 2021), OPA [41], OPE [47], PACO [24], HeLiS [25], as well as top-level ontologies, including DOLCE [42], CIDOC-CRM [43], and SUMO [44], to ensure a systematic, pattern-based development of our model. **Domain Ontologies:** SMASH ([[https://bioportal.bioontology.org/ontologies/SMASHPHYSICAL](https://bioportal.bioontology.org/ontologies/SMASHPHYSICAL)]([https://bioportal.bioontology.org/ontologies/SMASHPHYSICAL](https://bioportal.bioontology.org/ontologies/SMASHPHYSICAL)), accessed on 28 November 2021), which focuses on describing the semantic features of health care data and social networks, provides a well-developed physical activity type hierarchy that is divided into athletic sports, exercise, and occupational activity. The main drawback is the limited (or missing) coverage of relevant concepts, such as intensity and amount of physical activity, which are required for our case. OPA [41], the ontology for assessing physical activity and sedentary behavior, provides a baseline for characterizing physical activity, sedentary behavior, and the context in which it occurs, including factors such as space, time, weather, and social. Although it provides some \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt}} \hline \hline Intensity category & The purpose of HeLiFit and HeLiFit-Rule is to represent and reason upon the WHO/ACSM guidelines on physical activity and sedentary behavior. \\ \hline \multirow{4}{*}{Scope} & The HeLiFit ontology should focus on characterizing the notion of physical activity as used in the context of WHO/ACSM guidelines and allowing a mean to measure it, whereas HeLiFit focuses on reasoning over the different levels of adherence and issue recommendations to users. \\ \hline \multirow{4}{*}{Implementation language} & Web Ontology Language (OWL) for _HeLiFit_ and RDFox Rule Language for HeLiFit-Rule. \\ \hline \multirow{4}{*}{Target user} & The primary target users are health care professionals (User 1) working with aging frailty users (user 2), aiming to recommend or coach them on physical activity and exercise. Another group of target users (user 3) is professionals involved in the development of digital coach solutions to support physical activity and exercise recommendation, i.e., \\  & User 1—Health care professionals dealing with frailty User 2—Aging frailty users trainer User 3—Software developer or researcher working in the domain of digital coach for adherence in physical activity domain \\ \hline \multirow{4}{*}{Intended uses} & User 1: The intended uses of the ontology include: (1) supporting the process of physical activity regimen recommendation to a patient and (2) modifying current physical activity regimen for better adherence. \\ \cline{1-1}  & User 2: The intended use is to support the process of modification of user adherence based on changes in the user profile. \\ \cline{1-1}  & User 3: The intended use is to support the development of personalized solutions for physical activity maintenance and modification based on the user’s need. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: HeLiFit ontology and rules specifications. relevant concepts to model physical activity, including _TemporalEntity_, _SpaceEntity_, _IntensityOfActivity_ and _Anthropometry_, the concepts needed for formalizing WHO rules are only partially covered.