The OREDA database contains around 33000 objects, and several hundred features. Some of the features are shown in Tab 5.1, which were extracted by Sintef for use in the NOEMIE project with the SQL search given in appendix B.
FAILURE_EVENT.F_ID | M_ID | INVENTORY.I_ID | FM_CODE |
FD_NO | FAILURE_EVENT.REM_CODE | FC_CODE | OM_CODE |
FAILURE_EVENT.EC_CODE | F_DETECTED_DATE | F_DETECTED_DAY | F_DETECTED_month |
F_DETECTED_year | MAIN_EVENT.SU_CODE | MAC_CODE | MC_CODE |
MAIN_EVENT.MC_CODE | MAIN_EVENT.EC_CODE | M_MAINT_DATE | M_MAINT_DAY |
M_MAINT_MONTH | M_MAINT_YEAR | M_MEC_MANHOUR | M_EL_MANHOUR |
M_INST_MANHOUR | M_PATF_PERS | M_ACTIVE_MAINT | M_DOWNTIME |
INVENTORY_OWNER_ID | INVENTORY.INST_ID | OP_CODE | INVENTOR.EE_CODE |
DC_CODE | INVENTORY.EC.CODE | I_CHECKED_BY | I_CHECKED_DATE |
I_TAG_NO | I_SURV_START_DATE | I_SURV_START_DATE | I_SURV_END_DATE |
I_SURV_END_DAY | I_SURV_END_MONTH | I_SURV_END_YEAR | I_OPER_TIME |
I_OPER_TIME_CODE | I_NO_OF_STARTS | I_INSTALLED_DATE | I_INSTALLED_DAY |
I_INSTALLED_MONTH | I_INSTALLED_YEAR | I_SCRAPPED_AT_END | M_OTHER_MANHOUR |
M_RES_DRILL_RIG | M_RES_DIVING_VESSEL | M_RES_SERVICE_VESSEL | M_RES_DIVERS |
For our use, we reduced the number of objects and features. This was done to:
We selected features that are relevant for compressors according to advises from an OREDA database expert.
The values COMP in the column INVENTORY.EC_CODE was replaced by #COMP# to be able to select only the compressors with the following Unix command:
cat oreda332.txt | grep #COMP# > comp.txt
This produced 4646 objects.
The database was then imported into a text editor which could handle large files, where it was prepared in Rosetta format by including a new line with statements if the features are strings, integers or floats. Missing values were given the value ``Undefined''. The data was then imported into the Data Mining tool Rosetta [23] for manual inspection. We found that the feature MC_CODE had only one value ``CORRECT'' so it was removed. This gave the features that are described in Tab 5.2. A description of some of the codes used as feature values is given in appendix G.
Feature | Description |
INVENTORY_INST_ID | Installation identification. Unique number. |
FM_CODE | Failure mode. |
FD_NO | Failure description number. |
FAILURE_EVENT_REM_CODE | Failure remark. |
FC_CODE | Failure consequence code. |
MAIN_EVENT_SU_CODE | Subunit code. |
M_DOWNTIME | Downtime in hours. |
DC_CODE | Design class code. |
I_OPER_TIME | Operational time in hours. |
The ranges of the features M_DOWNTIME, I_OPER_TIME and FD_NO were reduced in Rosetta, and the ranges of the features FC_CODE and FM_CODE were reduced with the perl script given in appendix C. This produced the casebase used in experiments, with the features in Tab 5.2.