Appendix B: Expression Variable Reference

Created by Matthew St. Louis, Modified on Tue, 21 Apr at 4:36 PM by Matthew St. Louis

APPENDIX B

EXPRESSION REFERENCE

Expressions consist of one or more conditional statements that are evaluated for each point in the data set. Conditional statements can be enclosed in parentheses and combined using and and or. The following table lists all parameters that can be evaluated for each data point.

Variable	Description	Example
`Location`	Location information for the data point	`Location = null`
`Location.Latitude`	Latitude of the data point	`Location != null and Location.Latitude > 60`
`Location.Longitude`	Longitude of the data point	`Location != null and Longitude < 120`
`Time.Year`	Year component of the date/time	`Time.Year = 2010`
`Time.Month`	Month component of the date/time	`Time.Month = 1`
`Time.Hour`	Hour component of the date/time	`Time.Hour = 12`
`Time.Minute`	Minute component of the date/time	`Time.Minute < 30`
`Time.DayOfWeek`	Day of the week, with 0 = Monday and 6 = Sunday	`Time.DayOfWeek = 1`
`Speed`	Vessel speed, in knots	`Speed > 5`
`Heading`	Vessel direction, with North = 0, East = 90, South = 180, West = 270	`Heading > 0 and Heading < 180`
`Voltage`	Power supplied to the control box, in volts	`Voltage < 8`
`SatelliteError`	Based on GPS	`SatelliteError > 4`
`VideoRecording`	“true” if the VDL is currently recording, “false” otherwise	`VideoRecording = true`
`Drum`	Number of drum rotations since the last collected data point	`DrumRotations > 0`
`DrumRotationsPerMinute`	Number of drum rotations per minute since the last data point	`DrumRotationsPerMinute > 0`
`Pressure`	Pressure in PSI	`Pressure > 120`
`TimeGap.TotalSeconds`	Total seconds between this point and the previous data point	`TimeGap.TotalSeconds > 90`
`TimeGap.TotalMinutes`	Total minutes between this point and the previous data point	`TimeGap.TotalMinutes > 5`
`TimeGap.TotalHours`	Total hours between this point and the previous data point	`TimeGap.TotalHours > 1`
`TimeGap.TotalDays`	Total days between this point and the previous data point	`TimeGap.TotalDays > 1`
`EventDetail`	Event information for the data point	`EventDetail != null`
`EventDetail.EventNumber`	VDL event number for the event	`EventDetail != null and EventDetail.EventNumber = 3`
`EventDetail.Comment`	VDL event comment for the event	`EventDetail != null and EventComment = "Startup From Sleep"`
`DistanceTravelled`	Distance, in km, travelled since the last recorded data point	`DistanceTravelled > 0.5`
`CalculatedSpeed`	Speed, in km/h, calculated based on DistanceTravelled and TimeGap	`CalculatedSpeed > 10`
`RfidTag`	ID of the RFID tag scanned since the last data point	`RfidTag != 0`
`LineNumber`	Line number in the VM file that the data point comes from	`LineNumber > 5000`
`PressureRating`	Relative pressure rating derived by clustering the data. Can be: “NoData”, “Low”, “Medium”, “High”	`PressureRating = "High" or PressureRating = "Medium"`
`DrumSpeedAboveAverage`	“true” if the drum speed for the data point is above the average drum speed for the entire data set	`DrumSpeedAboveAverage = true`
`DrumSpeedRating`	Auto-calculated field based on statistical clustering of DrumRotationsPerMinute: 0 = slow, 1 = medium, 2 = fast	`DrumSpeedRating = 2`
`PressureAboveAverage`	“true” if the pressure for the data point is above the average pressure for the entire data set	`PressureAboveAverage = false`

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