Abstract: Heating, cooling, and ventilation equipment in a building may be controlled to improve building performance and/or occupant comfort. For a building, such as a low-load building, with multiple sub-systems of an overall HVAC system that can be actuated to impact indoor environmental conditions, an operational mode used to control such HVAC equipment may be selected. The selection may be based on input data from sensors, including indoor and outdoor environmental conditions, and occupancy level in combination with multiple models. Data collected over time may be used to form multiple types of models, including predictive models of building performance, future indoor conditions, and occupancy levels, and/or energy usage. The models may be used to select a control strategy. Based on the selected strategy and user preferences, a set of rules may be applied to generate control signals that control operation of HVAC subsystems.

Abstract: In a fault-tolerant computer system, a primary replica supervisor is interposed between an operating system and a primary replica of an application program being executed by a primary processor. An object-code editor locates calls to the operating system and loops in the application program and inserts instruction sequences that enable the replica supervisor to intercept the calls to the operating system, results returned by the operating system as a result of the calls and asynchronous events delivered by the operating system to the replica. A backup replica supervisor is similarly interposed between an operating system and a backup replica of the application program being executed by a backup processor. The primary replica interacts with an environment.

Abstract: In a fault-tolerant computer system, a primary replica supervisor is interposed between an operating system and a primary replica of an application program being executed by a primary processor. An object-code editor locates calls to the operating system and loops in the application program and inserts instruction sequences that enable the replica supervisor to intercept the calls to the operating system, results returned by the operating system as a result of the calls and asynchronous events delivered by the operating system to the replica. A backup replica supervisor is similarly interposed between an operating system and a backup replica of the application program being executed by a backup processor. The primary replica interacts with an environment.