A method includes simulating a token through a production process, the production process having a plurality of stages, determining whether the token may proceed from a first stage to a second stage in the production process, detecting event information as the token proceeds through the plurality of stages, and determining a root cause of a detected stall event based on the event information. The elevator car has spring-mounted rollers engaging guide rails and the system includes sensors detecting a position of the elevator car relative to the guide rails. By varying the power of the pulse used to generate the bubble, the printhead can operate with small, efficiently generated bubbles during normal printing, or it can briefly operate with large high energy bubbles if it needs to recover decapped nozzles. a thin glass layer, the optical element also being provided with an actuator for applying a force upon said flexible layer, said force being essentially symmetric relative to said axis thus bending the layer providing a lens surface and providing a curved refractive surface. The monomer units may be readily functionalized to enable the synthesis of polymers with diverse structural and electronic properties. The UE aperiodically transmits an SRS through a certain uplink component carrier of a plurality of UL CCs.