# Architecting Software for the Internet of Thing Based Systems
## 3 Research Method for the Mapping Study
### A Taxononical Classification of the Research on Architecting IoT Software  
We now answer **RQ-2**, which aims to investigate the existing research themes and their sub-themes that support architectural solution for the IoT based software systems. The answer to RQ-2 is based on our derived taxonomy of research themes, as presented in Figure 7 and Table 4. The research taxonomy refers to a systematic discovery, naming, organization and presentation of various research themes and their subthemes that provides a blue-print of topic under investigation to highlight the state of research and its contributions. We have derived the taxonomy by reviewing each study and applying (i) the thematic analysis and (ii) the ACM computing classification processes [15]. Figure 7 and Table 4 complement each other while presenting the taxonomy of research themes. Figure 7 mainly focuses on a visual illustration of the hierarchical classification of the identified research themes and their sub-themes, whereas Table 4 provides the corresponding evidence (i.e., reference to the published studies) and total number of studies that support a particular theme or sub-theme. We have  
Figure 6: An Overview of the frequency and types of publications.  
organized the focus and contributions of the research at two different levels for fine-grained analysis of existing research.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Research Area**} & \multicolumn{2}{c}{**Research Themes with Corresponding Evidences**} & \multirow{2}{*}{**Total Studies**} \\ \hline \multirow{4}{*}{1} & Cloud-based Software & a & Edge and Fog Computing [S1, S64, S5, S9, & 7 \\  & Ecosystem & b & Web of Things [S8, S18, S32, S46, S54] & 5 \\  & (**21/88** studies, i.e., 24\% approx. of total studies) & c & Cyber Physical Systems [S15, S17, S19, & 6 \\  & d & Cloud Computing Patterns [S29, S47, S53] & 3 \\ \hline \multirow{4}{*}{2} & Private and Secure Internet of & a & Securing Edge Computing Systems [S61] & 1 \\  & Things & Things & Security and Privacy of Enterprise & 2 \\  & (**07/88** studies, i.e., 08\% approx.) & b & Architectures Secure IoT Systems [S14, S24, & 4 \\ \hline \multirow{4}{*}{3} & Software Defined Networks & a & Interconnecting Software Services in IoTs & 3 \\  & (**10/88** studies, i.e., 11\% approx.) & b & Software Defined Security for IoT & 2 \\  & & Networks [S81, S25] & & \\  & & Resource Efficient IoT Networks [S33, S84, & 3 \\  & & S88] & d & Networking of Industrial IoTs [S12, S86] & 2 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Research themes, sub-themes, and corresponding evidences (published research studies).  
Figure 7: Taxonomical classification of research on architecting software for the internet of things.  
These two levels are named as Generic Classification (i.e., Research Themes) and Thematic Classification (i.e., Research Sub-themes), as in Figure 7 and Table 4. For example, the study [55], in general, supports Cloud-based Software Ecosystems (i.e., generic classification), whereas, [55] specifically focuses on supporting Edge and Fog Computing (i.e., thematic classification). In the following, we discuss both types of classification, which help us to present the challenges and architectural solutions with the emerging and futuristic trends later.