Both [s] and [ɵ] in English and the pronunciation of ‘스’ in Korean have [스] in common as phonetic symbols in HMJ phonetics. Because their original sound is [스] ‘equally’. The difference among them is that their articulate point, articulate method, etc. are different from one another respectively.
In HMJ phonetics an articulate point, an articulate method, etc. are described saparated from a phonetics symbol(s). Because an original sound(s) is the most important in a certain sound.
– in the thesis of ‘Hoon Min Jung phonetics the second edition’
HMJ phonetics uses the unique concept of an ‘original sound’. It means not a certain sound itself but a sound originally pronounced at the ‘articulate point’ to make it. Otherwise, a certain sound is just the combination of an original sound and other sounds derived. In HMJ phonetics only this original sound(s) is(are) written in brackets by a phonetic symbol(s). So HMJ phonetics’ phonetic symbols in a word are much more simple than IPA phonetics’ are.