A method of operating a laundry treatment machine, the method comprising: rotating a drum at a first velocity based on a first operation command value; sensing unbalance during a first velocity rotating section before vibrating the drum; vibrating the drum using a resonance frequency signal during the first velocity rotating section, wherein the resonance frequency signal is added to the first operation command value and the resonance frequency signal corresponds to a rotational velocity band in which the drum resonates during the first velocity rotating section; sensing unbalance during the step of vibrating the drum; calculating information regarding laundry position within the drum based on the unbalance sensed before vibrating the drum and the unbalance sensed during vibrating the drum; and determining whether to accelerate or decelerate the drum after the step of vibrating the drum; wherein the first velocity is a velocity at which laundry adheres to a circumferential surface of the drum during rotation of the drum, wherein the calculation step includes: sorting the laundry position into two groups based on the unbalance sensed before the forced vibration, wherein a first group includes no-load indicating no laundry within the drum and diagonal-load indicating diagonally spaced laundry within the drum, and a second group includes front-load, plane-load indicating the laundry located in the middle of the drum, and rear-load, distinguishing the no-load and the diagonal-load of the first group from each other or distinguishing the front-load, the plane-load, and the rear-load from one another of the second group based on unbalance sensed during the forced vibration section, determining information regarding laundry position as one of the no-load, the diagonal-load, the front-load, the plane-load, and the rear-load. rotating a drum at a first velocity based on a first operation command value; sensing unbalance during a first velocity rotating section before vibrating the drum; vibrating the drum using a resonance frequency signal during the first velocity rotating section, wherein the resonance frequency signal is added to the first operation command value and the resonance frequency signal corresponds to a rotational velocity band in which the drum resonates during the first velocity rotating section; sensing unbalance during the step of vibrating the drum; calculating information regarding laundry position within the drum based on the unbalance sensed before vibrating the drum and the unbalance sensed during vibrating the drum; and determining whether to accelerate or decelerate the drum after the step of vibrating the drum; wherein the first velocity is a velocity at which laundry adheres to a circumferential surface of the drum during rotation of the drum, wherein the calculation step includes: sorting the laundry position into two groups based on the unbalance sensed before the forced vibration, wherein a first group includes no-load indicating no laundry within the drum and diagonal-load indicating diagonally spaced laundry within the drum, and a second group includes front-load, plane-load indicating the laundry located in the middle of the drum, and rear-load, distinguishing the no-load and the diagonal-load of the first group from each other or distinguishing the front-load, the plane-load, and the rear-load from one another of the second group based on unbalance sensed during the forced vibration section, determining information regarding laundry position as one of the no-load, the diagonal-load, the front-load, the plane-load, and the rear-load. sorting the laundry position into two groups based on the unbalance sensed before the forced vibration, wherein a first group includes no-load indicating no laundry within the drum and diagonal-load indicating diagonally spaced laundry within the drum, and a second group includes front-load, plane-load indicating the laundry located in the middle of the drum, and rear-load, distinguishing the no-load and the diagonal-load of the first group from each other or distinguishing the front-load, the plane-load, and the rear-load from one another of the second group based on unbalance sensed during the forced vibration section, determining information regarding laundry position as one of the no-load, the diagonal-load, the front-load, the plane-load, and the rear-load.