The notation used within the CBR and DM communities vary, and it is therefore necessary to adopt one standard for notation to use in this report.
A database organized as a matrix has columns and rows. Within the CBR community the columns are called features , within the DM community they are often called attributes . We here adopt the notation features . The rows are called units , objects , records or cases in DM, but are here denoted objects .
We also define data , information , and knowledge [3]:
Data are patterns with no meaning; they are input to an interpretation process, i.e. to the initial step of decision making.
Information is data with meaning; it is the output from data interpretation as well as the input to, and output from, the knowledge-based process of decision making.
Knowledge is information incorporated in an agent's reasoning resources, and made ready for active use within a decision process; it is the output of a learning process.
Domain Knowledge is defined as knowledge of some part of the universe. For instance, domain knowledge of cars could be rules for saying when you should change your tires, in which situations you should not turn on the engine, etc.
A case can either be viewed as a data record or as a complex representation of a user experience.