In exemplary implementations of this invention, a basketball net or flat net measures the translational kinetic energy of a ball that passes through an aperture in the net or impacts the net. The net includes one or more electrically conductive cords, which have a resistance that varies depending on the degree to which the cord is stretched. From sensor measurements, a processor determines: (a) instantaneous rate of change of resistance, and (b) duration of a time period that begins when resistance exceeds a baseline (with hysteresis). In the case of a basketball net, a processor may calculate the translational kinetic energy of the ball as equal to a sum of two terms. The first term is inversely proportional to the square of the duration; the second is proportional to the square of the integral of the instantaneous rate of change of resistance over the time period.

In exemplary implementations of this invention, a basketball net or flat net measures the translational kinetic energy of a ball that passes through an aperture in the net or impacts the net. The net includes one or more electrically conductive cords, which have a resistance that varies depending on the degree to which the cord is stretched. From sensor measurements, a processor determines: (a) instantaneous rate of change of resistance, and (b) duration of a time period that begins when resistance exceeds a baseline (with hysteresis). In the case of a basketball net, a processor may calculate the translational kinetic energy of the ball as equal to a sum of two terms. The first term is inversely proportional to the square of the duration; the second is proportional to the square of the integral of the instantaneous rate of change of resistance over the time period.

A method and system are described for the continuous remote monitoring of the position and advance speed of a pig device inside a pipeline suitable for transporting a pressurized fluid, wherein the pipeline consists of a plurality of pipe sections joined to each other by welding. The method comprising the following steps: continuous acquisition and registration, by a plurality of measurement stations equipped with vibroacoustic sensors discretely located along the pipeline, of vibroacoustic signals due to hydraulic pressure transients, and/or to the vibrations generated by the pig device in movement in the contact/friction phases on the welding seams, and/or to other physical variations of the pipeline; analysis and processing, by a centralized control unit, of the vibroacoustic signals registered by the measurement stations to reveal, identify and reference the hydraulic/acoustic transients produced by the pig device during contact/friction with the weldings and/or with other variations in the internal section of the pipeline; continuous calculation of the linear position and advance speed of the pig device in relation to the time lapse between the vibroacoustic signals registered by at least two measurement stations installed along the pipeline.

A method and system are described for the continuous remote monitoring of the position and advance speed of a pig device inside a pipeline suitable for transporting a pressurized fluid, wherein the pipeline consists of a plurality of pipe sections joined to each other by welding. The method comprising the following steps: continuous acquisition and registration, by a plurality of measurement stations equipped with vibroacoustic sensors discretely located along the pipeline, of vibroacoustic signals due to hydraulic pressure transients, and/or to the vibrations generated by the pig device in movement in the contact/friction phases on the welding seams, and/or to other physical variations of the pipeline; analysis and processing, by a centralized control unit, of the vibroacoustic signals registered by the measurement stations to reveal, identify and reference the hydraulic/acoustic transients produced by the pig device during contact/friction with the weldings and/or with other variations in the internal section of the pipeline; continuous calculation of the linear position and advance speed of the pig device in relation to the time lapse between the vibroacoustic signals registered by at least two measurement stations installed along the pipeline.