Various examples provide a method and an apparatus of running applications. The collar serves to stabilize the position of the blade collar bolt thereby helping to prevent the bolt from loosening, which can in turn lead to the blade falling off the concrete saw. In an event data flows through both the primary path and the secondary path, the optical switch may be configured to monitor the primary path. A cermet layer is formed on the second semiconductor layer. The ventricular pacing is provided in response to determining a conduction abnormality exists and the ventricular pacing is inhibited in response to determining a conduction abnormality does not exist.