ate ▁only ▁a ▁subset ▁of ▁those ▁rules , ▁where ▁the ▁subset ▁contains ▁at ▁least ▁one ▁rule ▁and ▁usually ▁way ▁fewer ▁than ▁M ▁rules . ▁In ference ▁is ▁done ▁one ▁rule ▁at ▁a ▁time . ▁So , ▁at ▁the ▁output ▁of ▁the ▁In ference ▁block , ▁there ▁will ▁be ▁one ▁or ▁more ▁fired - rule ▁f uz zy ▁output ▁sets . ▁ ▁In ▁most ▁engineering ▁applications ▁of ▁a ▁F LS , ▁a ▁number ▁( and ▁not ▁a ▁f uz zy ▁set ) ▁is ▁needed ▁as ▁its ▁final ▁output , ▁e . g ., ▁the ▁consequ ent ▁of ▁the ▁rule ▁given ▁above ▁is ▁" Rot ate ▁the ▁val ve ▁a ▁bit ▁to ▁the ▁right ." ▁No ▁automatic ▁val ve ▁will ▁know ▁what ▁this ▁means ▁because ▁" a ▁bit ▁to ▁the ▁right " ▁is ▁a ▁lingu istic ▁expression , ▁and ▁a ▁val ve ▁must ▁be ▁turned ▁by ▁numerical ▁values , ▁i . e . ▁by ▁a ▁certain ▁number ▁of ▁degrees . ▁Con sequently , ▁the ▁fired - rule ▁output ▁f uz zy ▁sets ▁have ▁to ▁be ▁converted ▁into ▁a ▁number , ▁and ▁this ▁is ▁done ▁in ▁the ▁Fig . ▁ 3 ▁Output ▁Process ing ▁block . ▁ ▁In ▁a ▁type - 1 ▁F LS , ▁output ▁processing , ▁called ▁Def uzz ification , ▁maps ▁a ▁type - 1 ▁f uz zy ▁set ▁into ▁a ▁number . ▁There ▁are ▁many ▁ways ▁for ▁doing ▁this , ▁e . g ., ▁compute ▁the ▁union ▁of ▁the ▁fired - rule ▁output ▁f uz zy ▁sets ▁( the ▁result ▁is ▁another