A non-transitory computer-readable recording medium stores a program that causes a computer to execute a process including: performing a first conversion processing to convert a value indicating each event, and to convert, based on conversion information that indicates a group of the value and an identification value that corresponds to values belonging to the group; constructing information with occurrence probabilities by connecting identification values; performing second conversion processing to convert a value indicating each event included in event data, and to convert values that belong to a group indicated in the conversion information into an identical identification value corresponding to the group based on the conversion information; and detecting an anomaly based on a result of comparison between the constructed information and the identification value.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A non-transitory computer-readable recording medium having stored therein a detection program that causes a computer to execute a process including: performing a first conversion processing to convert a value indicating each event that is included in history log into an identification value corresponding to the value, and to convert, based on conversion information that indicates a group of the value and an identification value that corresponds to values belonging to the group, values that belong to a group indicated in the conversion information into an identical identification value that corresponds to the group; constructing information with occurrence probabilities by connecting identification values that are obtained by conversion by the first conversion processing in order of occurrence of the event sequentially from a root, and by assigning an occurrence probability of an event that corresponds to the identification value per identification value; performing second conversion processing to convert a value indicating each event included in event data that is input according to an event has occurred into an identification value corresponding to the value, and to convert values that belong to a group indicated in the conversion information into an identical identification value corresponding to the group based on the conversion information; and detecting an anomaly based on a result of comparison between the constructed information with occurrence probabilities and the identification value that is obtained by conversion by the second conversion processing. 2. The non-transitory computer-readable recording medium according to claim 1, wherein the conversion information indicates a range of values as the group, and the first and the second conversion processing converts values within the range indicated in the conversion information into an identical identification value that corresponds to the range. 3. The non-transitory computer-readable recording medium according to claim 2, wherein the process further including: calculating a statistical distribution of values indicating respective events that are included in the history log, and of creating conversion information in which a range of the values and an identification value corresponding to the range is defined, wherein the first and the second conversion processing performs conversion processing based on the created conversion information. 4. The non-transitory computer-readable recording medium according to claim 1, wherein the conversion information indicates order of array of values as the group, and the first and the second conversion processing converts values arranged in the order of array indicated in the conversion information into an identical identification value corresponding to the order of array. 5. The non-transitory computer-readable recording medium according to claim 4, wherein the process further including: calculating an appearance frequency according to order of array of values that indicate respective events included in the history log, and of creating conversion information in which the order of array having the appearance frequency equal to or higher than a predetermined value and an identification value that corresponds to the order of array are defined, wherein the first and the second conversion processing performs conversion processing based on the created conversion information. 6. A detection method comprising: performing a first conversion processing to convert a value indicating each event that is included in history log into an identification value corresponding to the value, and to convert, based on conversion information that indicates a group of the value and an identification value that corresponds to values belonging to the group, values that belong to a group indicated in the conversion information into an identical identification value that corresponds to the group by a processor; constructing information with occurrence probabilities by connecting identification values that are obtained by conversion by the first conversion processing in order of occurrence of the event sequentially from a root, and by assigning an occurrence probability of an event that corresponds to the identification value per identification value by the processor; performing second conversion processing to convert a value indicating each event included in event data that is input according to an event has occurred into an identification value corresponding to the value, and to convert values that belong to a group indicated in the conversion information into an identical identification value corresponding to the group based on the conversion information by the processor; and detecting an anomaly based on a result of comparison between the constructed information with occurrence probabilities and the identification value that is obtained by conversion by the second conversion processing by the processor. 7. The detection method according to claim 6, wherein the conversion information indicates a range of values as the group, and the first and the second conversion processing converts values within the range indicated in the conversion information into an identical identification value that corresponds to the range. 8. The detection method according to claim 7, further comprising: calculating a statistical distribution of values indicating respective events that are included in the history log, and of creating conversion information in which a range of the values and an identification value corresponding to the range is defined, by the processor, wherein the first and the second conversion processing performs conversion processing based on the created conversion information. 9. The detection method according to claim 6, wherein the conversion information indicates order of array of values as the group, and the first and the second conversion processing converts values arranged in the order of array indicated in the conversion information into an identical identification value corresponding to the order of array. 10. The detection method according to claim 9, further comprising: calculating an appearance frequency according to order of array of values that indicate respective events included in the history log, and of creating conversion information in which the order of array having the appearance frequency equal to or higher than a predetermined value and an identification value that corresponds to the order of array are defined, by the processor, wherein the first and the second conversion processing performs conversion processing based on the created conversion information. 11. A detection apparatus comprising a processor that executes a process comprising: performing a first conversion processing to convert a value indicating each event that is included in history log into an identification value corresponding to the value, and to convert, based on conversion information that indicates a group of the value and an identification value that corresponds to values belonging to the group, values that belong to a group indicated in the conversion information into an identical identification value that corresponds to the group; constructing information with occurrence probabilities by connecting identification values that are obtained by conversion by the first conversion processing in order of occurrence of the event sequentially from a root, and by assigning an occurrence probability of an event that corresponds to the identification value per identification value; performing second conversion processing to convert a value indicating each event included in event data that is input according to an event has occurred into an identification value corresponding to the value, and to convert values that belong to a group indicated in the conversion information into an identical identification value corresponding to the group based on the conversion information; and detecting an anomaly based on a result of comparison between the constructed information with occurrence probabilities and the identification value that is obtained by conversion by the second conversion processing. 12. The detection apparatus according to claim 11, wherein the conversion information indicates a range of values as the group, and the first and the second conversion processing converts values within the range indicated in the conversion information into an identical identification value that corresponds to the range. 13. The detection apparatus according to claim 12, wherein the process further comprising: calculating a statistical distribution of values indicating respective events that are included in the history log, and of creating conversion information in which a range of the values and an identification value corresponding to the range is defined, by the processor, wherein the first and the second conversion processing performs conversion processing based on the created conversion information. 14. The detection apparatus according to claim 11, wherein the conversion information indicates order of array of values as the group, and the first and the second conversion processing converts values arranged in the order of array indicated in the conversion information into an identical identification value corresponding to the order of array. 15. The detection apparatus according to claim 14, wherein the process further comprising: calculating an appearance frequency according to order of array of values that indicate respective events included in the history log, and of creating conversion information in which the order of array having the appearance frequency equal to or higher than a predetermined value and an identification value that corresponds to the order of array are defined, by the processor, wherein the first and the second conversion processing performs conversion processing based on the created conversion information.