Abstract: A state monitor for monitoring the state of a system and including a calculator and a memory; the system being controlled by a command defining a plurality of modes of operation of the system, each mode of operation corresponding to applying a command of constant value; the memory containing a set of stored state matrices representing, for each mode of operation of the system, the value of the projection of its state in time; and the calculator being configured, during operation of the system, to determine estimated values for the state of the system at a given instant with the state functions and of its state at an earlier instant.

Abstract: A field of pneumatically-actuated regulator valves, and more specifically a regulator valve for regulating a flow of gas from an upstream duct to a downstream duct. The regulator valve has a passage to enable the upstream duct to communicate with the downstream duct, a movable member arranged to vary a flow section of the passage, and an actuator with an internal chamber in communication with an exhaust duct and an admission duct to connect to the upstream duct, the actuator being arranged to move the movable member. For control purposes, the regulator valve has a control unit incorporating at least one state observer to estimate at least one pressure that exists in the internal chamber from a measured position of the movable member and from a measured upstream pressure, and from an opening value for at least one valve installed in the admission duct and/or the exhaust duct.

Abstract: A state monitor for monitoring the state of a system and including a calculator and a memory; the system being controlled by a command defining a plurality of modes of operation of the system, each mode of operation corresponding to applying a command of constant value; the memory containing a set of stored state matrices representing, for each mode of operation of the system, the value of the projection of its state in time; and the calculator being configured, during operation of the system, to determine estimated values for the state of the system at a given instant with the state functions and of its state at an earlier instant.

Abstract: The process according to the invention consists in that the freshly collected ram semen is first diluted at between 25.degree. and 32.degree.C and notably at 30.degree.C, in a diluent without glycerol containing lactose and egg yolk, and in then diluting, at between 3.degree. and 5.degree.C and notably at 4.degree.C, the mixture previously obtained in a diluent containing glycerol, said diluent essentially comprising powdered milk and sodium citrate, in conditioning in straws the so diluted semen and in freezing it in liquid nitrogen at about -75.degree.C. The invention also relates to the diluent used in the above process.The process is useful for preserving ram semen by freezing for subsequent artificial insemination of ewes.