How to determine the part of speech tags of words succeeding 不 like these? How to determine the part of speech tags of words succeeding 不 like these?

In standard Chinese word segmentation datasets, 趕不上 is segmented as 趕 不 上, and 找不到 is segmented as 找 不 到; 趕上 is segmented as 趕上 itself, and 找到 is segmented as 找到 itself. 

Both POS tags of 趕上 and 找到 can be easily determined, which are almost always VV, but "上" and "到" in 趕不上 and 找不到 are difficult to determine their POS tags.

What are their POS tags according to
http://repository.upenn.edu/cgi/viewcontent.cgi?article=1039&amp;context=ircs_reports
?
Basically:

趕不上 is a [(趕) verb + (不) potential particle + (上) directional  particle] structure.

找不到 is a [(找) verb + (不) potential particle + (到) attainment / achievement particle] structure.


In 趕上, 趕 is the verb &quot;to rush&quot;, and 上 is a directional particle that indicates the direction of the verb apply to (forward)

趕 = to rush; 趕上 = to catch up

In 找到, 找 is the verb &quot;to find&quot;, and 到 is a particle that indicates the success of the verb (attainment / achievement)

找= to find; 找到 = have found

I had explained the role of potential particle in other answers before:

「得」or 「不」 are the two potential particles that indicate &quot; &quot;able , or &quot;unable&quot;
*Potentially, you either able or unable to. That's why they are called potential particles.