▁mass ▁assigned ▁to ▁Any ▁refers ▁to ▁the ▁proportion ▁of ▁evidence ▁that ▁can ▁not ▁be ▁assigned ▁to ▁any ▁of ▁the ▁other ▁states , ▁which ▁here ▁means ▁evidence ▁that ▁says ▁there ▁is ▁a ▁light ▁but ▁does ▁not ▁say ▁anything ▁about ▁what ▁color ▁it ▁is . ▁In ▁this ▁example , ▁the ▁proportion ▁of ▁evidence ▁that ▁shows ▁the ▁light ▁is ▁either ▁Red ▁or ▁Green ▁is ▁given ▁a ▁mass ▁of ▁ 0 . 0 5 . ▁Such ▁evidence ▁might , ▁for ▁example , ▁be ▁obtained ▁from ▁a ▁R / G ▁color ▁blind ▁person . ▁D ST ▁lets ▁us ▁extract ▁the ▁value ▁of ▁this ▁sensor ' s ▁evidence . ▁Also , ▁in ▁D ST ▁the ▁Null ▁set ▁is ▁considered ▁to ▁have ▁zero ▁mass , ▁meaning ▁here ▁that ▁the ▁signal ▁light ▁system ▁exists ▁and ▁we ▁are ▁exam ining ▁its ▁possible ▁states , ▁not ▁spec ulating ▁as ▁to ▁whether ▁it ▁exists ▁at ▁all . ▁ ▁Com bin ing ▁belief s ▁Bel ief s ▁from ▁different ▁sources ▁can ▁be ▁combined ▁with ▁various ▁fusion ▁operators ▁to ▁model ▁specific ▁situations ▁of ▁belief ▁fusion , ▁e . g . ▁with ▁D emp ster ' s ▁rule ▁of ▁combination , ▁which ▁comb ines ▁belief ▁constraints ▁that ▁are ▁dict ated ▁by ▁independent ▁belief ▁sources , ▁such ▁as ▁in ▁the ▁case ▁of ▁combining ▁hints ▁or ▁combining ▁prefer ences . ▁Note ▁that ▁the ▁probability ▁masses ▁from ▁propos itions ▁that ▁contradict ▁each ▁other ▁can ▁be ▁used ▁to ▁obtain ▁a ▁measure ▁of ▁conflict ▁between ▁the ▁independent ▁belief ▁sources . ▁Other ▁situations ▁can ▁be ▁mode led ▁with ▁different ▁fusion ▁operators , ▁such