Tutorial on the Semantic Web

Tutorial on th e Semantic W ebKen B aclawskiNortheas tern Univ ersityVersatile Information S ystems OutlineI. Ontology Lan guagesA. From flat files to hierarchies and XMLB. Rule ba sed sy stemsC. Resource D escription Fra meworkD. Web Ontology LanguageII.Onto logy ApplicationsA. On tology based information retrie valB. Tr ansformation languages an d t oolsC. Ba yesian We b: Combining logic and probabilityD. Si tuation Aw arenessIII. Onto logy Design Flat Fi le Re cordsConside r the following r ecords in flat fil e:011500 18.66 0 0 62 46 .271020111 25 .22001001 26.93 0 1 63 68 .951521001 32.651010020100 33.95 1 0 65 92.532041101 18.93011002 17.38 0 0 67 50 .351111100 42.160001What do th ey me an? Metadata The ex planation o f what data means i s cal led metadata or “ data about data.”  For a flat fi le or datab ase the metadata is called the sc hema.NAME LENGTH FORMAT LABELinstudy 6 MMDDYY Date of randomization into studybmi 8 Num Body Mass Index.obesity 3 0=No 1=Yes Obesity (30.0 <= BMI)ovrwt 8 0=No 1=Yes Overweight (25 <= BMI < 30)Height 3 Num Height (inches)Wtkgs 8 Num Weight (kilograms) Weight 3 Num Weight (pounds)Record Structures A flat fi le is a col lection of r ecords. A record consists of fields. Each r ecord in a fl at fil e has the same number and ki nds of fi elds as any other rec ord i ...