▁he ▁did ▁not ▁have ▁day - to - day ▁management ▁responsibility ▁for ▁the ▁program ▁but ▁did ▁have ▁o vers ight ▁responsibility . ▁ ▁Ell ings on ▁retired ▁from ▁M IT RE ▁in ▁ 1 9 8 9 . ▁ ▁J T ID S ▁was ▁not ▁created ▁by ▁a ▁single ▁individual . ▁R ather ▁it ▁was ▁the ▁cul min ation ▁of ▁a ▁group ▁of ▁individuals ▁each ▁having ▁expert ise ▁in ▁specific ▁discipl ines ▁including ▁but ▁not ▁limited ▁to ▁system ▁engineering , ▁oper ational ▁analysis , ▁cost ▁benefit ▁analysis , ▁message ▁standards , ▁software ▁development , ▁communic ations , ▁signal ▁processing , ▁vulner ability ▁analysis , ▁error ▁detection ▁and ▁correction , ▁anten na ▁design , ▁multip ath ▁analysis , ▁elect romagnet ic ▁compatibility ▁ ▁mechanical ▁engineering , ▁navigation , ▁specification ▁generation ▁and ▁others . ▁ ▁For ▁a ▁considerable ▁period ▁during ▁J T ID S ▁conception ▁as ▁many ▁as ▁ 5 0 ▁people ▁were ▁employed ▁full - time ▁in ▁its ▁development ▁with ▁as ▁many ▁as ▁ 5 0 ▁more ▁in ▁part - time ▁supporting ▁roles . ▁In ▁the ▁en su ing ▁years ▁the ▁program ▁has ▁transition ed ▁from ▁an ▁int ensive ▁development ▁effort ▁to ▁a ▁more ▁classical ▁ac quisition ▁effort . ▁ ▁Development ▁has ▁continued ▁but ▁efforts ▁have ▁been ▁orient ed ▁more ▁toward ▁incorpor ation ▁of ▁break through s ▁in ▁technology ▁and ▁efforts ▁to ▁improve ▁quality ▁and ▁reduce ▁size , ▁weight ▁and ▁cost . ▁ ▁In ▁the ▁early ▁ 1 9 9 0 s ▁the ▁Navy ▁took ▁over ▁the ▁executive ▁ ▁management ▁of ▁the ▁program .