ことにする vs. ことに決める


My Japanese text book says that a present-tense verb followed by ことにする is used
to indicate making a decision about the action. But I've also noticed the verb
決める, and that it's usage is very similar.

So supposing we have a sentence such as:

朝ご飯を作った後に、ジョギングすることにした。(After making breakfast, I decided to jog.)

My question is, would there be any specific semantic difference if 決める was
used? In all the cases that I've seen, the final する has always been in the
past-tense, but 決める has been in a variety of forms; is this possible
difference of the two?

Thanks! :)




This is what "A Dictionary of Basic Japanese Grammar" has to say on the matter
of ことにする vs ことに決める:

> _Koto ni suru_ and _koto ni kimeru_ 'determine to do s.t.' are virtually
> identical in meaning. The difference is that the former is an idiom and,
> therefore, frequently used in colloquial speech, while the latter is
> appropriate when the speaker is talking about a relatively important
> decision in a rather decisive manner. Also, _koto ni suru_ can be used to
> mean 'I hereby decide to ~' but _koto ni kimeru_ cannot. Thus, [1] below
> cannot be rephrased by _koto ni kimeru_.
>
> [1] 私は会社をやめることに **します** /???きめます。  
>  _Watashi wa kaisha wo yameru koto ni shimasu /???kimemasu._  
>  (I've decided to quit my company.)




This is what "A Dictionary of Basic Japanese Grammar" has to say on the matter
of ことにする vs ことに決める:

> _Koto ni suru_ and _koto ni kimeru_ 'determine to do s.t.' are virtually
> identical in meaning. The difference is that the former is an idiom and,
> therefore, frequently used in colloquial speech, while the latter is
> appropriate when the speaker is talking about a relatively important
> decision in a rather decisive manner. Also, _koto ni suru_ can be used to
> mean 'I hereby decide to ~' but _koto ni kimeru_ cannot. Thus, [1] below
> cannot be rephrased by _koto ni kimeru_.
>
> [1] 私は会社をやめることに **します** /???きめます。  
>  _Watashi wa kaisha wo yameru koto ni shimasu /???kimemasu._  
>  (I've decided to quit my company.)

