Lower and upper approximations of upward (downward) union of decision classes in Variable Consistency Dominance-Based Rough Set Approach (VC-DRSA) are the basis for extraction of decision rules, so computations of approximations is a necessary step in knowledge representing and reduction based on VCDRSA. In this paper, a matrix-based method for computing lower approximations of upward and downw...

Although the set of reachable states of a lossy channel system (LCS) is regular, it is well-known that this set cannot be constructed eeectively. In this paper, we characterize signiicant classes of LCS for which the set of reachable states can be computed. Furthermore, we show that, for slight generatlizations of these classes, computability can no longer be achieved. To carry out our study, w...

Virulence of Newcastle disease virus (NDV) is mainly determined by the amino acid sequence of the fusion (F0) protein cleavage site. Full-length NDV cDNA clone pNDFL was used to generate infectious NDV with defined mutations in the F0 cleavage site (RRQRR downward arrow L, GRQGR downward arrow F, RRQGR downward arrow F, RGQRR downward arrow F and RKQKR downward arrow F). All the mutants were vi...

This paper explores empirical merits of a version Agree that is defined based on Minimal Search (MS-Agree). Compared to the standard Agree, MS-Agree, essentially search algorithm, uniquely allows independent assignment its target and domain. unique feature enables MS-Agree accommodate both upward downward agreement phenomena, offers unified analysis for negative concord, inflection doubling, mu...