Educational Data Mining - a subset of educational research. Educational researchers have always collected data (classroom observation) or mined data (retention rates, final marks, mid term marks etc.). The ability to produce and collect large quantities of data is a recent development. As well, large quantities of raw data are/may being generated and recorded without purpose and are available for synthesis and refinement at a later date.
Learning analytics is the measurement, collection, analysis and reporting of data about learners and their contexts, for purposes of understanding and optimising learning and the environments in which it occurs. Source: https://tekri.athabascau.ca/analytics/about
Learning analytics is an emerging field in which sophisticated analytic tools are used to improve learning and education. It draws from, and is closely tied to, a series of other fields of study including business intelligence, web analytics, academic analytics, educational data mining, and action analytics." Source: Elias, T. (2011) Learning Analytics: Definitions, Processes, Potential (PDF)
Linked Data is about using the Web to connect related data that wasn't previously linked, or using the Web to lower the barriers to linking data currently linked using other methods.
In general QR codes are an easy way to match a physical object to virtual information. I have used them quite succesfully in presentations on the beamer to link people to more information online.
They may soon be superseded by either RFID tags and near field communication or by the rapid advances in live visual processing and understanding by computers.
An attempt to structure and link data on the internet that enables us to share meaning with computers. Information about items and ideas is written into the code in order for computers to better understand. (i.e., Fido=dog=animal).
Such additional information would enable computers to provide more accurate such results. The ultimate vision seems to involve computers and electronic devices to become active participants in the Internet.