A system for condensing a sequential data set on a computer system, the system comprising a controller configured to: receive the sequential data set including a plurality of data values in a serial sequence; analyze the sequential data set to identify a number of occurrences in the sequential data set of each of a plurality of unique data value pairs, wherein each unique data value pair includes a first data value and a second data value, the second data value being different than the first data value; and generate a condensed data set based on the sequential data set, wherein the condensed data set includes a data element for each of the plurality of unique data value pairs, wherein each data element includes an identification of the first data value of the unique data value pair, an identification of the second data value of the unique data value pair, and a count indicative of the number of occurrences in the sequential data set of first data value of the unique data value pair immediately followed by the second data value of the unique data value pair; characterised in that the controller is further configured to generate a graphical signature indicative of the content of the sequential data set by positioning a plurality of nodes in the graphical signature, wherein each node of the plurality of nodes corresponds to a different data value in the condensed data set, and positioning a plurality of vectors in the graphical signature, wherein each vector corresponds to a different data element of the condensed data set, and wherein each vector appears in the graphical signature as including a line beginning at a node corresponding to the first data value of the data element and extending to a node corresponding to the second data value of the data element; and wherein the controller is further configured to detect an occurrence of an anomalous event by comparing the graphical signature generated for the sequential data set to a second graphical signature indicative of a sequential data set for a normal operation, and wherein the controller is further configured to detect a difference between the graphical signature and the second graphical signature. receive the sequential data set including a plurality of data values in a serial sequence; analyze the sequential data set to identify a number of occurrences in the sequential data set of each of a plurality of unique data value pairs, wherein each unique data value pair includes a first data value and a second data value, the second data value being different than the first data value; and generate a condensed data set based on the sequential data set, wherein the condensed data set includes a data element for each of the plurality of unique data value pairs, wherein each data element includes an identification of the first data value of the unique data value pair, an identification of the second data value of the unique data value pair, and a count indicative of the number of occurrences in the sequential data set of first data value of the unique data value pair immediately followed by the second data value of the unique data value pair; characterised in that the controller is further configured to generate a graphical signature indicative of the content of the sequential data set by positioning a plurality of nodes in the graphical signature, wherein each node of the plurality of nodes corresponds to a different data value in the condensed data set, and positioning a plurality of vectors in the graphical signature, wherein each vector corresponds to a different data element of the condensed data set, and wherein each vector appears in the graphical signature as including a line beginning at a node corresponding to the first data value of the data element and extending to a node corresponding to the second data value of the data element; and wherein the controller is further configured to detect an occurrence of an anomalous event by comparing the graphical signature generated for the sequential data set to a second graphical signature indicative of a sequential data set for a normal operation, and wherein the controller is further configured to detect a difference between the graphical signature and the second graphical signature.