관한, 대한 and 관해(서), 대해(서)
* ~에 관한, ~에 대한 = "about (something)" as an adjective. E.g. 전기에 관한 이론 (theories about electricity).
* ~에 관해(서), ~에 대해(서) = "about (something)" as an adverb. E.g. 전기에 대해 말하다 (talk about electricity).
(The difference between 관- and 대- is negligibly small. You can consider them to be the same.)
So (~에) 관한/대한 always comes before a noun while (~에) 관해/대해 comes before a verb.
- 이제부터 안건에 대한 설명을 드리겠습니다 (설명 = noun).
- 이제부터 안건에 대해 설명하겠습니다 (설명하다 = verb).
1 이것은 [[인권에 관한] 문제]다 - This is [an issue [concerning human rights]].
2 우리는 [[[인권에 대한] 문제]를 제기한다] - We [raise [an issue [concerning human rights]]].
3 우리는 [인권에 대해] [문제를 제기한다] - We [raise an issue] [concerning human rights].
* 2 and 3 show that the two types of usages can look similar in some rare cases.
All these phrases are simple verb conjugations, so it's useful to know how they are derived.
~ㄴ/은(at the end of 관한 and 대한) is a verb conjugation which converts the verb into an adjective expressing an action completed in the past. But the verbs 관하다 and 대하다(the base forms), are stative in meaning (like "concerns"), and they express the idea of what something is about, not a completed action as with the other action verbs.
~해(서) and its original form ~하여(서) are a ~아/어/여 conjugation of 하다 (하(다) + ~아/어/여 -> 하여 -> 해). ~아/어/여 connects two verbs, where the first verb with ~아/어/여 ending functions as an adverb qualifying the main verb that follows it(앉아 있다). It can also acquire ~서 (대해 -> 대해서) for emphasis in most cases.
While it's normally used to indicate two closely connected actions (물을 끓여 마신다 = boil the water and drink it), 관하다 and 대하다 create the idiomatic meaning of "talk/discuss/etc ABOUT something" (물에 관해 이야기한다 = talk about water). But the form remains the same).