*4.3.5. Layout change function*

As described in the previous section, the layout of the analytic view was calculated by the OpenOrd (edge-cutting value: 0.91). In addition to that, the analytic views can be redrawn by the OpenOrd (edge-cutting value: 0.94 or 0.88), LGL, Fruchterman-Raingold, or Kamada-Kawai [26]. When the users select a layout, the layout algorithm is executed in the background, the resulting layout information is stored and the view is redrawn. If the layout information is stored in advance, the layout is redrawn immediately. The layout calculation time depends on the number of nodes, and the average time is a few seconds to a few minutes.

#### *4.3.6. Custom analytic view function*

*4.3.4. Query function and export function*

**Figure 8.** Feature phrases in the selected nodes.

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**Figure 9.** SPARQL search widget.

The background data in the Mapping Science have been converted to RDF data and stored in a graph database. Therefore, the analytic views provide a high-level search using a formal query language, SPARQL, as in **Figure 9**. For example, the users can search for articles, which have >0.8 similarities with articles cited 100+ times from journals with >10 impact factor (such articles might be obscure but important). When the users click a node ID in the result table,

The analytic views were composed by the info map algorithm, but the users can create the customized Analytic views by keyword search. When the users enter keywords into the widget in the portfolio view, the nodes are extracted by the full-text search for all nodes in five research areas, and then the layout is calculated by the OpenOrd based on the cosine similarities of the extracted nodes. For example, an analytic view for studies related to neural networks and artificial intelligence across multiple research areas can be created by keywords such as "Artificial Intelligence [AND] Neural Network." This function could help find interdisciplinary studies. The calculation time depends on the number of nodes, and the average time is a few seconds to a few minutes. The information on the customized analytic views is stored in the background; the same view is immediately displayed for the second time. The customized analytic view can provide the same analytical functions, such as keyword search, visualization of statistical information, visualization of the cumulative changes by year, and layout change.
