document: Finding surprising patterns in a time series database in linear time and space The problem of finding a specified pattern in a time series database ( i.e. query by content ) has received much attention and is now a relatively mature field . In contrast , the important problem of enumerating all surprising or interesting patterns has received far less attention . This problem requires a meaningful definition of `` surprise '' , and an efficient search technique . All previous attempts at finding surprising patterns in time series use a very limited notion of surprise , and\/or do not scale to massive datasets . To overcome these limitations we introduce a novel technique that defines a pattern surprising if the frequency of its occurrence differs substantially from that expected by chance , given some previously seen data .
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