The lattice of linear classes in prime-valued logics
On the Time Complexity of the Problem Related to Reducts of Consistent Decision Tables
In recent years, rough set approach computing issues concerning reducts of decision tables have attracted the attention of many researchers. In this paper, we present the time complexity of an algorithm computing reducts of decision tables by relational database approach. Let DS = (U, C ∪ {d}) be a consistent decision table, we say that A ⊆ C is a relative reduct of DS if A contains a reduct of DS. Let s = <C ∪ {d} , F> be a relation schema on the attribute set C ∪ {d}, we say that A ⊆ C...
Reasoning Methods for Designing and Surveying Relationships Described by Sets of Functional Constraints
This work is supported by the Hungarian Scientific Research Fund (OTKA), grant T042706. Current methods of database schema design are usually based on modeling the real world as entity (or object) classes with relationships among them. Properties of relationships can be described by semantical database constraints. One of them is functional dependency, which has a key role in traditional database design. The three basic types of binary relationships that can be described by functional...
A Distance-Based Method for Attribute Reduction in Incomplete Decision Systems
There are limitations in recent research undertaken on attribute reduction in incomplete decision systems. In this paper, we propose a distance-based method for attribute reduction in an incomplete decision system. In addition, we prove theoretically that our method is more effective than some other methods.
An Algorithm to Mine Normalized Weighted Sequential Patterns Using a Prefix-projected Database
Sequential pattern mining is an important subject in data mining with broad applications in many different areas. However, previous sequential mining algorithms mostly aimed to calculate the number of occurrences (the support) without regard to the degree of importance of different data items. In this paper, we propose to explore the search space of subsequences with normalized weights. We are not only interested in the number of occurrences of the sequences (supports of sequences), but also concerned about...
A Method to Construct an Extension of Fuzzy Information Granularity Based on Fuzzy Distance
In fuzzy granular computing, a fuzzy granular structure is the collection of fuzzy information granules and fuzzy information granularity is used to measure the granulation degree of a fuzzy granular structure. In general, the fuzzy information granularity characterizes discernibility ability among fuzzy information granules in a fuzzy granular structure. In recent years, researchers have proposed some concepts of fuzzy information granularity based on partial order relations. However, the existing...
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