Reading through a number of design reports, I often see the statement that one of the measurements is surface weight on bit (WOB or SWOB). I doubt it. If a team can measure surface WOB you should patent it. It is more likely that you are making an indirect measurement that leads to hook load or something similar. Then you compare on-bottom and off-bottom readings. The industry typically asks the driller to periodicaly tare the off-bottom value which is subtracted from the current calculated hookload to calculate the WOB.
You are writing a scientific paper. Be extremely specific in the words you use. Note the errors possible in any measurement and in how that measurement is then handled during transport, storage and computation. The drilling automation community is working now to identify the uncertainty in various measurement methods. Keep this in mind as you enter that community.