People seem to fall prey to adverbials like “however” and “rather” seducing them into running on sentences.
This type of approach has been used in previous models, however, the presented algorithm adopts a different foundation.
But these words are not conjunctions, subordinating or otherwise. They are adverbs, like “on the other hand” or “unfortunately”. The following is, presumably, clearly infelicitous.
This type of approach has been used in previous models, unfortunately, the presented algorithm adopts a different foundation.
By the same token, so is the sentence with “however”. It is easily corrected:
This type of approach has been used in previous models; however, the presented algorithm adopts a different foundation.
or
This type of approach has been used in previous models. The presented algorithm, however, adopts a different foundation.