This paper also develops a fuzzy competitive learning scheme for these new reference vector parameters, and applies the algorithm to the difficult task of clustering documents.

Gauss-Newton error minimization is used to transform six-dimentional reference vector to quaternion as a part of observations for EKF, which significantly reduces the computational requirement.

Data: An object; a generic reference that is carried along to listeners; often a collection class (such as a Vector or Hashtable) or a customized data object.