# Ontology-Based Methodology for Knowledge Acquisition from Groupware
## 2 Literature Survey
### Ontology Equality of Concepts
The proposed approach is based on making aggregated judgements on the semantic correspondences between the entities/concepts of different ontologies using knowledge that is represented by multiple external resources. Another two difficulties they addressed in their suggested approach were: (i) identifying and dealing with inconsistencies of semantic relations between concepts in an ontology; and (ii) using an integrated statistical and semantic technique to address the issue of missing background knowledge in the exploited knowledge bases. An ontology merger technique that is based on semantic similarity between concepts is proposed by [PERSON] and [PERSON] [50]. It converts ontology into a formal context before calculating the semantic similarity of the concepts that are contained within. It obtains the ontology after reduction and concept lattice development. To integrate heterogeneous tourist information for online trip planning, [PERSON] and [PERSON] [51] introduced an ontology-based approach and a formal concept analysis (FCA) technique. In accordance with their respective perspectives, two ontologies were developed, one for travelers and one for tourism information suppliers. The ontology for travelers is based on research in the tourism field. Using the FCA approach, the ontology for tourist information providers is created by merging heterogeneous web tourism information. A summary of the most recent research in this domain taken from the above review, including a comparison with this proposed research, is given in Table 1. \begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Authors/Year** &
\begin{tabular}{c} **Source of New** \\ **Knowledge** \\ \end{tabular} & \multicolumn{1}{p{56.9 pt}}{**Research Focus**} & \multicolumn{1}{p{56.9 pt}}{**Sampled Ontology**} & \multicolumn{1}{p{56.9 pt}}{**Techniques Used**} & \multicolumn{1}{p{56.9 pt}}{**Evaluation**} \\ \hline [PERSON] et al. [42] & Existing ontology & Adding a concept from one ontology & WordNet & Similarity measure & Correlation among ontologies \\  & & another ontology & & & \\ \hline [PERSON] et al. [43] & Existing ontology & Merging two or more existing ontologies & WordNet & & & \\  & & & & & \\ \hline [PERSON] et al. [44] & Existing ontology & Matching two or more existing ontologies & WordNet & Similarity measure & Recall, Precision, F-measure \\ \hline [PERSON] and [PERSON] [45] & Existing ontology & Matching two or more existing ontologies & Biomedical ontologies & Similarity measure & Recall, Precision, F-measure \\ \hline [PERSON] and [PERSON] [46] & Existing ontology & Mapping two or more existing ontologies & Transportation and vehicles ontologies & Granular computing & Use case \\ \hline [PERSON] et al. [47] & Existing ontology & Mapping two or more existing ontologies & OAEI dataset & Mapping similarity & Accuracy \\ \hline [PERSON] [48] & Existing ontology & Aligning two or more existing ontologies & Metamodel-based ontologies & NA & NA \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of the most recent related research with the proposed study. Several salient points may be drawn from Table 1:  
* Most of the previous research efforts in this domain are similar in that all are looking for new knowledge to add into a destination ontology from another existing ontology. * Within such efforts, there is no clear consensus on the notion of equality, similarity, and equivalence of concepts, which is a necessity for the recognition of new concepts from any given source to be compared with an existing ontology. * The literature is also scant on a technique for the insertion/hooking of a newly recognized concept into an existing ontology. In sum, the literature is indeed scant on a formalized technique for the identification and insertion/hooking of a new concept into an existing ontology from other existing ontologies, let alone when the source is from sentences (free text), and especially from groupware.