title: Classification integration and reclassification using constraint databases.
abstract: OBJECTIVE
  We propose classification integration as a new method for data integration from different sources. We also propose reclassification as a new method of combining existing medical classifications for different classes.
  
  
  BACKGROUND
  In many problems the raw data are already classified according to a set of features but need to be reclassified. Data reclassification is usually achieved using data integration methods that require the raw data, which may not be available or sharable because of privacy and legal concerns.
  
  
  METHODS
  We introduce general classification integration and reclassification methods that create new classes by combining in a flexible way the existing classes without requiring access to the raw data. The flexibility is achieved by representing any linear classification in a constraint database.
  
  
  RESULTS
  The experiments using support vector machines and decision trees on heart disease diagnosis and primary biliary cirrhosis data show that our classification integration method is more accurate than current data integration methods when there are many missing values in the data. The reclassification problem also can be solved using constraint databases without requiring access to the raw data.
  
  
  CONCLUSIONS
  The classification integration and the reclassification methods are applied to two particular data sets. Beside these particular cases, our general method is also appropriate for many other application areas and may yield similar accuracy improvements. These methods may be also extended to non-linear classifiers.
authors.affiliation: Department of Computer Science and Engineering, University of Nebraska-Lincoln, 358 Avery Hall, Lincoln, NE 68588, USA. revesz@cse.unl.edu
authors.forename: Peter
authors.initials: P
authors.lastname: Revesz
authors.forename: Thomas
authors.initials: T
authors.lastname: Triplet
mesh_terms: D000465:Algorithms; D001185:Artificial Intelligence; D057225:Data Mining; D019992:Databases as Topic; D020000:Decision Support Systems, Clinical; D003663:Decision Trees; D006331:Heart Diseases / Q000145:classification / Q000175:diagnosis; D006801:Humans; D016014:Linear Models; D008105:Liver Cirrhosis, Biliary / Q000145:classification / Q000175:diagnosis; D016347:Medical Records Systems, Computerized; D008962:Models, Theoretical; D009323:Natural Language Processing; D010363:Pattern Recognition, Automated; D011237:Predictive Value of Tests; D011379:Prognosis; D049490:Systems Biology; D018875:Vocabulary, Controlled