Usage Count
Two new metrics of usage are added to the Web of Science platform with the field tags of U1 and U2 respectively.
The value of U1 is the number of times the full text of a record has been accessed or a record has been saved in the last 180 days.
The value of U2 is the number of times the full text of a record has been accessed or a record has been saved since February 1, 2015.
Follow the link below for detailed descriptions
http://images.webofknowledge.com/WOKRS519B3/help/WOK/hp_usage_score.html
In CiteSpace 4.0.R2, U1 and U2 are utilized in the visualization of a network of cited references. Instead of calling them U1 or U2, CiteSpace refers them as Usage180 and Usage2013 so
that their meaning is easy to grasp.
Figure 1. Usage counts can be used as one of the node selection criteria.
Figure 2. Controls of the size of a node and its label based on two types of usage count.
The usage count of a cited reference is shown as a red circle filled with a semi-transparent white color. The size of the circle is proportional to the corresponding usage count. The larger a circle, the higher its usage is.
You can label highly used items by controls on the Article Labeling panel to the right of the visualization canvas. The figure above shows a view based on the U2 field, i.e. Usage2013.
Figure 3. Nodes are rendered by their corresponding usage counts in the last 180 days (as of 10/14/2015).
The CHEN CM (2012) in Figure 3 is the 2012 review of regenerative medicine published in EXPERT OPINION ON BIOLOGICAL THERAPY. The usage count fields U1 and U2 of the 2012 article are as follows:
......
NR 62
TC 19
Z9 20
U1 44
U2 235
......
The CHEN CM (2014) in Figure 3 is the 2014 follow-up review of regenerative medicine, also published in EXPERT OPINION ON BIOLOGICAL THERAPY. The usage count fields U1 and U2 of the 2014 article are as follows:
......
NR 86
TC 3
Z9 4
U1 49
U2 127
......
References
Chen, C., Dubin, R., Kim, M. C. (2014) Emerging trends and new developments in regenerative medicine: A scientometric update (2000-2014). Expert Opinion on Biological Therapy, 14 (9), 1295-1317.
Chen, C., Hu, Z., Liu, S., Tseng, H. (2012) Emerging trends in regenerative medicine: A scientometric analysis in CiteSpace. Expert Opinions on Biological Therapy, 12(5), 593-608.