I edited a friend’s draft on the following sentence:
I deleted “of”, after checking the verb “Monitor” in Longman, and noticed the object comes directly after “monitor”. [ Careful monitoring technical disciplines comments].
So, am I right? Maybe both with or without “of” are correct?
Does this refer to the monitoring of peoples comments about technical disciplines? Neither sentence is particularly easy to understand but by removing the “of” you’ve completely changed the meaning of the sentence so without context or knowing more it’s impossible to say which is right.
Agree: don’t make sense either way.
Are the disciplines making the comments? If so there should be a possessive apostrophe after the word “disciplines”. That would make a little more sense, but it would still be clumsily written.
Disciplines don’t make comments, people do.
Context required.
Yes, People in different disciplines make those comments. So, it should be " Technical comments from / by diciplines".
But, my question is seeking an answer for the “of” after the gerund “Monitoring”
Forget about the first example and please take this one:
Monitoring of all activities in mechanical discipline
Monitoring all activities in mechanical discipline.
Note: Even if this second example is crying for a context, then take this one
Monitoring of [ object ],
or Monitoring [ object ].
I think there’s no more room to clarify my point.
They are different meanings in that case.
Monitoring all activities - verb gerund, with implied subject. E.g. [X will be] monitoring all activities.
Monitoring of all activities - acting as a noun. E.g. [The] monitoring of all activities.
Therefore it depends what you want the sentence to say. Further context is still required to get it right.
Thank you for your time and care.
The phrase is one of the responsibilities which a person has in his job. He has itemized them in his CV. He wanted to say that monitoring technical comments from different disciplines is his responsibility.
How about “Monitoring technical comments from different disciplines” then? No need to use tortuous construction when simplicity will do. Eschew obfuscation. 
Yes, this is what I did for him. omitting “of” after Monitoring. But I asked to make sure that I did the right job leaving out “of”.
In fact, I asked here to get more details (grammatically), so that I’ll be able to explain and defend my correction in case he would ask me later why I did this.
lemme ask in another way; is it common in standard English to use “of” after monitoring?
like:
Government is intensifying monitoring of foreign loans. or it should be without “of”
Government is intensifying monitoring foreign loans.
In both phrases the action of monitoring is going to be increased. isn’t it?
Any difference in meaning? [ to my ears, nope ] , and I’m just asking.
“Of” is perfectly correct in that case. But your repeated omission of definite and indefinite articles is confusing the matters in which it acts as a noun:
The government is intensifying the monitoring of foreign loans.
The government is intensifying monitoring foreign loans.
The latter sentence is very clumsy with two gerunds in a row, the second of which implies “the act of monitoring” but (IMO) still just about correct.
The former is much more understandable, however, where “the monitoring of” is taking the form of a noun.