This analysis will detect the "bursty" terms used in the title of papers in the dataset. Since the burst detection algorithm is case-sensitive, it is necessary to normalize the field to be analyzed before running the algorithm. Select the table "101 Unique ISI Records" and run 'Preprocessing > Topical > Lowercase, Tokenize, Stem, and Stopword Text.' Check the "Title" box to indicate that you want to normalize this field:
Select the resulting "with normalized Title" table in the Data Manager and run 'Analysis > Topical > Burst Detection' with the following parameters:
The "Gamma" parameter controls the ease with which the burst automaton can change states. The higher the "Gamma" value, the smaller the list of bursts generated.
View the file "Burst detection analysis (Publication Year, Title): maximum burst level 1":
In this table, there are six columns: "Word," "Length," "Weight," "Strength," "Start," and "End." The "Word" field identifies the specific character string which was detected as a "burst." The "Length" field indicates how long the burst lasted (over the selected time parameter). The "Weight" field denotes the intensity of the burst, i.e., how great the change in the word frequency that triggered the burst. The "Start" field indentifies when the burst began (again, according to the specified time parameter). And the "End" field indicates when the burst stopped. A null value in the "End" field indicates that the burst lasted until the last date present in the dataset.
To visualize these results, select the "Burst Detection" table in the Data Manager and run 'Visualization > Temporal > Horizontal Bar Graph' with the following parameters:
Horizontal bar graphs are used to visualize numeric data over time, generating labeled horizontal bars. A PostScript file containing the horizontal bar graph will appear in the Data Manager:
Select the PostScript file and save it in your desired directory.
Open and view the file using the workflow from Section 2.4 Saving Visualizations for Publication.
Figure 5.31: Visualization of bursts for terms in the title of papers in the Alessandro Vespignani dataset (gamma parameter = 1)
Select the table 'with normalized Title' in the Data Manager and run 'Analysis > Topical > Burst Detection' with the following parameters:
Notice that the value for the gamma parameter is now set to 0.5. The parameter gamma controls the ease with which the automaton can change states. With a smaller gamma value, more bursts will be generated. Running the algorithm with these parameters will generate a new table named "Burst detection analysis (Publication Year, Title): maximum burst level 1.2" in the Data Manager. Visualize the new results by running 'Visualization > Temporal > Horizontal Bar Graph' with the same parameters as before:
A new PostScript file entitled 'HorizontalBarGraph_maximum burst level 1.ps.2' containing the horizontal bar graph will be produced in the Data Manager:
Save and view the file using the workflow described in Section 2.4 Saving Visualizations for Publication.
Figure 5.32: Visualization of bursts for terms in the title of papers in the Alessandro Vespignani (gamma parameter equals 0.5).