Liliana Cojocaru

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– The paper presents an original survey on Web ontology editing tools, in respect with Semantic Web actual technologies. The material is focused on features that these tools might expose: granularity of expressivity, Web standards compliance, reasoning support, provided APIs and, not least, the interoperability issues. The comparative study is used a(More)
<i>Watson-Crick Automata</i> are a counterpart of finite automata working on a <i>Watson-Crick tape</i> composed of double stran-ded sequences of symbols linked by a complementarity relation like DNA molecules. Consequently, these devices have as input double strands of strings of symbols arranged in a pairwise affinity similar to Watson-Crick(More)
The regulated rewriting mechanism is one of the most efficient methods to augment the Chomsky hierarchy with a large variety of language classes that lay within it. In this paper we investigate the derivation process in regulated rewriting grammars such as matrix grammars, random context grammars, and programmed grammars by studying their Szilard languages.(More)
We introduce a normal form for context-free grammars, called Dyck normal form. This is a syntactical restriction of the Chomsky normal form, in which the two nonter-minals occurring on the right-hand side of a rule are paired nonterminals. This pairwise property allows to define a homomorphism from Dyck words to words generated by a grammar in Dyck normal(More)
This paper concerns linear context-free languages (LIN). We prove that LIN ⊆ NC 1 (under UE * −uniformity reduction). We introduce a new normal form for context-free grammars, called Dyck normal form. Using this new normal form we prove that for each context-free language L there exist an integer K and a homomorphism ϕ such that L = ϕ(D K), where D K ⊆ DK ,(More)