Abstract: A computer-implemented method of preparing an anonymised dataset for use in data analytics. The method includes the steps of: (a) labelling elements of a dataset to be analysed according to a labelling scheme; (b) selecting one or more labelled elements of the dataset to be replaced with a distance preserving hash; and for each selected element: (c) partitioning a data plane including the selected element into a plurality of channels, each channel covering a different distance space of the data plane; (d) hashing, using a cryptographic hash, data associated with the channel of the data plane in which the selected element resides, to form the distance preserving hash; and (e) replacing the selected element with the distance preserving hash.

Abstract: There is provided a system for detecting a drowning person within a water body, the system comprising (i) sonar sensors for forming a three dimensional grid of sonar waves within the water body, the grid having three dimensional grid cells; (ii) a movement path tracing unit adapted to be connected to the sonar sensors for tracing a movement path of a person within the water body by determining a sequence of successive grid cells crossed by the person within the grid in the course of said movement path, the determination of the successive grid cells being made based on detected propagation delays of the sonar waves forming the grid; and (iii) a drowning detection unit adapted to be connected to the movement path tracing unit for analyzing the movement path of the person and issuing an alarm when the movement path of the person is indicative of a drowning person movement path. There is also provided a kit and method for detecting a drowning person within a water body.

Abstract: There is provided a system for detecting a drowning person within a water body, the system comprising (i) sonar sensors for forming a three dimensional grid of sonar waves within the water body, the grid having three dimensional grid cells; (ii) a movement path tracing unit adapted to be connected to the sonar sensors for tracing a movement path of a person within the water body by determining a sequence of successive grid cells crossed by the person within the grid in the course of said movement path, the determination of the successive grid cells being made based on detected propagation delays of the sonar waves forming the grid; and (iii) a drowning detection unit adapted to be connected to the movement path tracing unit for analysing the movement path of the person and issuing an alarm when the movement path of the person is indicative of a drowning person movement path. There is also provided a kit and method for detecting a drowning person within a water body.