## 4 Empirical Study
### Knowledge Fusion
#### 4.3.1 Knowledge Fusion within a Document  
_Intent_ sentence merging. The semantics of an _intent_ sentence depends on its context. If a design _intent_ sentence contains the same artifact words and the same _intent_ phrases of each constituent _artifact_, then the two design _intent_ sentences are considered to be identical. As shown in Figure 10, an \"identical_to\" relationship can be established between the two _intent_ sentence nodes via a simple comparison of the duplicated _artifact_ words and _intent_ phrases. Furthermore, the cosine similarity analysis of two _intent_ sentences is an effective approach for an _intent_ sentence merge. Figure 8: Example of artifact aggregation relations extraction. _Issue_ sentence merging. For the patent documents, we assume that the same patent can only solve one design problem. If two _issues_ are described in the same BDU, the two _issues_ can be considered as the same one and can be combined, as shown in the first two rows of Table 5. Furthermore, a cosine similarity analysis-based knowledge merge of two _issue_ sentences is also an effective approach. _Artifact_ word merging. The _artifact entities_ and _artifact elements_ are represented as words, and the _artifact_ words in different _literature_ express various semantics, depending on the context. This makes it difficult to determine whether two feature words are identical, through semantic similarity analysis alone. Therefore, _artifact_ merging only applies to _artifacts_ in the same document, and _artifacts_ between different documents should not be merged. _Artifact_ merging is performed by comparing whether the feature words of the two _artifacts_ represent the same one. As shown in Figure 11, a system is described in the patent name \"Methods and systems of an all-purpose broadband network\", including a \"local optimization server\", and a \"wireless RF access\". The \"local optimization server\" includes \"uplinks\", \"mobile devices\", \"part on air interface data rate priority value\", \"scheduler\", and others. At the same time, the \"wireless radio frequency access\" includes a \"scheduler  
Figure 9: An example of a DKN extracted from the patent document. In the figure, the big node in the center (��⃝ 10228704) represents the patent, and 10228704 is the patent number; middle sized nodes (�⃝ 1-_artifact, argument, issue, intent_) are DR sentence nodes. Other small nodes are feature word nodes, such as _artifact entities_, _artifact elements_, _intent_, _pros_ and _cons_, and others. that provides an uplink\" and a \"downlink air interface access to mobile devices\". The _artifact entity_ \"local optimization server\" in the sentence node (10311) is identical to the _artifact element_ \"local optimization server\" in the sentence node (10362). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Relation** & **Source** & **Issue** \\ \hline \multirow{4}{*}{_issuellenticalTo_} & & A system and method disclosed herein for providing communications security for small, low-powered systems that are actively and securely controlled over a wireless data link addresses the problems faced by prior art systems. There is therefore a need for a small, low-power, security-certifiable system for controlling actively guided ordinance. \\ \cline{1-1}  & & \\ \cline{1-1}  & & \\ \cline{1-1}  & & \\ \cline{1-1}  & & \\ \cline{1-1}  & & \\ \end{tabular}
\end{table} 
Table 5: Semantic similarity analysis for _issue_ sentence fusion. Figure 10: Example of fusion of design intent based on literature structure. However, if the same design document contains multiple sets of _artifact entities_ and _artifact elements_, although the extracted names are the same, the meanings are different. This requires the comparison of two sets of _artifact elements_ to distinguish whether the _artifact entities_ are the same. As shown in Figure 12, both node 445 and node 446 have a \"set of flight_status detecting sensors\" _ArtifactEntity_. However, they are different because of their different _artifactElements_.