B
ased on the intuitionistic fuzzy sets and the possibility theory. Fuzzy approach is fully utilized by using intuitionistic sets extended to represent not only uncertain, but also contradictory data within same framework. Consequently the results of the possibility theory are generalized for the case of contradictory data. Same as with the shades of uncertainty we introduce the shades of contradiction from feasible to infeasible. This allows us to operate uncertain and contradictory data in a unified, certain and feasible way.
 F
uzzy features. All the data the system operates on are considered fuzzy. For this a notion of fuzzy feature is introduced as a generalization of crisp features known in classical machine learning. Similar to statistical pattern recognition, a feature is a measurable function with the possibility used as the measure. Both the features and the things viewed through features are consistently supposed fuzzy. By these two ways uncertainty comes into play. It might be a crisp thing described in vague terms, like a number being big or small. Or it can be a precise description of something uncertain, like a temperature said to be n degrees. There could be a mixture of both.
 F
uzzy classes. Within this framework classes take a natural interpretation of distinguished features. This has an appealing advantage of treating the same feature sometimes as given input data, sometimes as the result of a classification. Just same as humans do.
 N
umeric, enumeration features and features based on linguistic variables. The system supports a variety of feature types:
• Discrete features take values from some crisp finite enumeration set. For instance red, green, blue;
• The numeric features with integer or real values. Because the system consistently rely on fuzzy approach, all numeric features may take standard numeric, interval and fuzzy numeric values;
• Linguistic features taking values from a set of linguistic variables. Linguistic variables may be used to replace large domain sets of real numbers with finite sets of linguistic variables conceivable to human beings. Piecewise-linear shapes of membership functions supported, which includes triangular, trapezoid, shoulder etc.
 U
ser-defined features. The system is open for definition of new features beyond built-in classes of numeric, nominal and linguistic ones.
 D
erived and evaluated features. Along with the measured features the system supports the features deduced from other features. This opens a wide range of possibilities of defining feature conversions, evaluating features from other features, using different representations of same features.
 C
lassifiers as features for building hierarchical systems. Because classes and features are treated in a unified way, the classifiers can be used as features which values yield classifications. This opens a door to building large hierarchical classification systems. In such a system output of a lower-level classification subsystem could be smoothly used for training higher levels of the system.
 A
utomatic refinement in case of dependent features. The problem of dependent features is well known as most difficult to solve. Although use of dependent features is less problematic in the possibility theory than in the probability theory. Because the result have a form of estimations which remains true no matter whether features involved are dependent or not. Yet the quality of the estimations may significantly drop. The system has a highly integrated mechanism of refinement of the estimations for dependent features known to be derived from other features. The approach is based on the constraints dynamically set on the feature values as the system navigates along the decision paths. The constraints are set and dropped fully transparent to the data base used for the teaching and classification.
 I
ncremental learning. The way a training set is split into pieces does not affect the result of training. Further the classifiers can be continuously tuned on the fly as new training examples appear. Thus a classifier can be put into a controlling loop to act as an adaptive fuzzy controller.
 F
uzzy control language support. The includes a compiler of an intuitionistic extension of the Fuzzy Control Language.
 O
bject-oriented software design. The system fully utilizes the advantages of modern approach to software architecture and design based on objects.
 F
eatures, training sets and classifiers are extensible objects. Features, training sets, classifiers are designed as abstract data types with defined interface. They can be extended as necessary to provide alternative implementations or functionality without breaking the existing code.
 A
utomatic garbage collection. The system objects are accessed through handles and get automatically destroyed when no more used. This design prevents memory leaks and dandling pointers.
 G
eneric data base support through ODBC. Important system objects such as features, training sets, classifiers can be made persistent by storing them in a data base. The system interfaces data bases through ODBC, which is supported by a great variety of data base engines and platforms. The objects backed by a data base can be processed directly there or converted to memory mapped objects when performance is essential.
 D
esigned in Ada. All software was developed in Ada 2005, the language of choice for safety-critical systems. Ada was the first internationally standardized object-oriented programming language, designed especially for developing portable long-living large systems, where maintainability is essential. The language standard provides interfaces to other programming languages allowing a smooth integration of Ada programs into practically any environment.
 I/O
facilities. Text I/O is provided for teaching sets and classifiers. Teaching sets can be imported in an intuitive format from text files.
 HTML
output. Training sets and classifiers can be output in directly HTML format, supporting a web-ready solution.
 A
dvanced graphical user interface. The graphical user interface is based on GTK+, a cross-platform widget toolkit. The graphical interface is optional the system can be used fully programmatically.
 E
xamples of use. The system is delivered with an set of samples varying from ones illustrating usage of the system components to examples of training on real- life and size data.