Abstract: A computer-automated system and method derives occupancy information about a space—e.g., the location, counts, and movement of people within the space—from observations and predictions of a probabilistic simulation that is guided by sensor observations, but which is not dependent on these observations, and one in which all sensors collectively and emergently cooperate in the selection of occupancy information that best fits the observations. The described system bears a resemblance to digital twins, but with fundamental differences in how the simulation operates and produces results, and without being overly concerned or restricted by maintaining physical equivalence in the model. The simulation allows the system to provide estimates even when there are no direct observations and to incorporate a wide range of temporal information (including data from the past, present and future) and spatial information (size, structure, and use).

Abstract: Failures in a fault-tolerant computer system which includes two or more input/output processors connected to a data communication system are detected by monitoring data communication. The computer system is able to detect failures associated with a primary input/output processor, as well as with a standby input/output processors, and is also able to discriminate between failures of the input/output processors and communication failures in the data communication network itself. In addition to using heartbeat-like transmissions, various other categories of data communication are also used to detect failures. The system is able to detect failures when the input/output processors are on a common network segment, allowing the processors to monitor identical data traffic, as well as when the processors are on different segments where, as a result of filtering behavior of network elements such as active hubs, the processors may not be able to monitor identical data traffic.