A computer-implemented method comprising: obtaining, for each of one or more network entities, a time series of values of a measurement parameter for respective timestamps, the time series of values including measured values and a special numerical value at one or more timestamps, wherein the time series includes the special numerical value at a given timestamp for replacing a value of the measurement parameter when no measured value is available for the measurement parameter at the given timestamp; parsing the time series of values to determine which numerical value in the time series of values corresponds to the special numerical value, wherein the parsing includes detecting same-values sequences having a minimum length in the time series of values and generating a set of at least one value including the value of each of the detected same-values sequences having the minimum length, wherein if the set of values includes only one value, the sole value in the set of values is identified as being the special numerical value; wherein the parsing includes computing a count of value changes occurring in a sliding time window of a given length applied to the time series of values to detect at least one portion of the time series in which a measured value is available for the measurement parameter; assigning flags to the values in the time series of values based on the result of the parsing, wherein a flag assigned to a value obtained at a given timestamp indicates whether the measurement was or not available at the given timestamp in the time series of values. obtaining, for each of one or more network entities, a time series of values of a measurement parameter for respective timestamps, the time series of values including measured values and a special numerical value at one or more timestamps, wherein the time series includes the special numerical value at a given timestamp for replacing a value of the measurement parameter when no measured value is available for the measurement parameter at the given timestamp; parsing the time series of values to determine which numerical value in the time series of values corresponds to the special numerical value, wherein the parsing includes detecting same-values sequences having a minimum length in the time series of values and generating a set of at least one value including the value of each of the detected same-values sequences having the minimum length, wherein if the set of values includes only one value, the sole value in the set of values is identified as being the special numerical value; wherein the parsing includes computing a count of value changes occurring in a sliding time window of a given length applied to the time series of values to detect at least one portion of the time series in which a measured value is available for the measurement parameter; wherein the parsing includes detecting same-values sequences having a minimum length in the time series of values and generating a set of at least one value including the value of each of the detected same-values sequences having the minimum length, wherein if the set of values includes only one value, the sole value in the set of values is identified as being the special numerical value; wherein the parsing includes computing a count of value changes occurring in a sliding time window of a given length applied to the time series of values to detect at least one portion of the time series in which a measured value is available for the measurement parameter; assigning flags to the values in the time series of values based on the result of the parsing, wherein a flag assigned to a value obtained at a given timestamp indicates whether the measurement was or not available at the given timestamp in the time series of values.