# A Heterogeneous Battlefield Situation Information Sharing Method Based on Content
## 3 Entity Oriented General Description of Battlefield Situation Information
### Structure of the Concept-Logic Tree
#### 3.1.2. Concept-Logic Tree of Entity Relationships  
Take \(r_{a}\), \(r_{b}\), and \(r_{c}\) as three kinds of entity relationships, then several main relations among entity relationships can be described as follows; where entity relationships are directed, e.g., \(e_{x}\xrightarrow{r_{a}}e_{y}\) means an entity \(e_{x}\) is connected with another entity \(e_{y}\) through relationship \(r_{a}\). * Inclusion: If \(e_{x}\xrightarrow{r_{a}}e_{y}\Rightarrow e_{x}\xrightarrow{r_{b}}e_{y}\), then \(r_{b}\) include \(r_{a}\), which is denoted as \(r_{a}{\subseteq}r_{b}\). * Metex: If \(e_{x}\xrightarrow{r_{a}}e_{y}\Rightarrow e_{x}\xrightarrow{-r_{b}}e_{y}\), then \(r_{a}\) and \(r_{b}\) are mutually exclusive, e.g., \(r_{a}\) and \(r_{b}\) cannot exist between two entities at the same time, which is denoted as \(r_{a}\perp r_{b}\). * Compatibility: If \(r_{a}\) and \(r_{b}\) can exist between two entities at the same time, then \(r_{a}\) and \(r_{b}\) are compatible, which is denoted as \(r_{a}\parallel r_{b}\). * Inverse: If \(e_{x}\xrightarrow{r_{a}}e_{y}\Rightarrow e_{y}\xrightarrow{r_{b}}e_{x}\), then \(r_{a}\) and \(r_{b}\) possess the inverse relationship, which is denoted as \(r_{a}^{-1}{=}r_{b}\). Since the entity relationship describes the mutual relation between two entities, there must be an inverse relation \(r_{b}\) for any \(r_{a}\). At this time, the semantics expressed by \(e_{x}\xrightarrow{r_{a}}e_{y}\) and \(e_{y}\xrightarrow{r_{b}}e_{x}\) are equivalent. In particular, if \(r_{a}^{-1}{=}r_{a}\), then \(r_{a}\) is considered to be symmetric. * Accessibility: If \(e_{x}\xrightarrow{r_{a}}e_{y}\wedge e_{y}\xrightarrow{r_{b}}e_{z}\Rightarrow e _{x}\xrightarrow{r_{c}}e_{z}\), then \(r_{a}\) and \(r_{c}\) are accessible, which is denoted as \(r_{a}\)\(\rightleftarrows r_{c}\) or \(r_{a}\bullet r_{b}{=}r_{c}\). From the perspective of semantic expression, entity relationships reflect the semantic connections between entities. Thus, when judging the relations among entities, the logic of semantics expressed by entity relationships is mainly considered. For example, when describing the relationship among combat units, if \(e_{x}\xrightarrow{r_{a}}e_{y}\) means \(e_{x}\) command \(e_{y}\), \(e_{y}\xrightarrow{r_{b}}e_{x}\) means \(e_{y}\) is commanded by \(e_{x}\), and \(e_{x}\xrightarrow{r_{c}}e_{z}\) means \(e_{x}\) collaborate with \(e_{z}\), then \(r_{a}\) and \(r_{b}\) possess a reciprocal relation, while \(r_{b}\) and \(r_{c}\) are compatible. Clarifying the hierarchy between entity relationships is conducive to further clarifying the reasoning rules among entity relationships and to realize semantics based reasoning on the basis of obtaining entity description information. Table 3 shows some reasoning rules based on entity relationships. Figure 7. Structure of the entity class classification tree. Based on the above relationships, the concept of the entity relationship concept-logic tree is proposed, which organizes the entity relationships hierarchically according to the logical and semantic relations among entity relationships. **Definition 4** (entity relationship concept-logic tree). : _Suppose \(T_{\text{LEC}}(Fr)\) is a tree with \(Fr\) as the root node, and other entity relationships defined in the research field are organized as child nodes of \(Fr\), according to the logical and semantic relations among entity relationships. In this tree, \(Fr\) represents an entity relationship with the highest abstraction degree._  
Generally, the concept-logic model can be viewed as a concept model, which organizes the concepts describing entity information in a structured way and is further used to realize the consistent description of information. Obviously, in order to construct a general concept-logic model to realize heterogeneous information integration, the concepts used in it should be selected based on the consensus of researchers in field of study. The mapping of concepts from the general concept-logic model to that used in each system should be designed.