In this paper we introduce the notions of uniformly quasi-primary ideals and uniformly classical quasi-primary submodules that generalize the concepts of uniformly primary ideals and uniformly classical primary submodules; respectively. Several characterizations of classical quasi-primary and uniformly classical quasi-primary submodules are given. Then we investigate for a ring $R$, when any fi...

Applications of augmented reality have a great immersion potential for education, edutainment or cultural heritage presentations. The combination of intuitive and playful interaction with multi-faceted presentation options proved to be an effective mixture that attracts viewers to educational or cultural content. We introduce a multi-touch augmented reality system (MARS) using two display units...

We investigated the applicability of probabilistic context-free grammars to syllabi cation and grapheme-to-phoneme conversion. The results show that the standard probability model of context-free grammars performs very well in predicting syllable boundaries. However, our results indicate that the standard probability model does not solve grapheme-to-phoneme conversion su ciently although, we va...

We present a measure for evaluating Probabilistic Context Free Grammars (PCFG) based on their ambiguity resolution capabilities. Probabilities in a PCFG can be seen as a filtering mechanism: For an ambiguous sentence, the trees bearing maximum probability are single out, while all others are discarded. The level of ambiguity is related to the size of the singled out set of trees. Under our meas...

Context-awareness refers to systems that unobtrusively adapt to the environment of their users on the basis of context information, popularly known as contextaware systems. One inherent property of context information is that it possesses a certain quality, such as the certainty with which it has been determined and so on. Different aspects of this quality are represented by a set of indicators...

The assignment of probabilities to the productions of a context-free grammar may generate an improper distribution: the probability of all finite parse trees is less than one. The condition for proper assignment is rather subtle. Production probabilities can be estimated from parsed or unparsed sentences, and the question arises as to whether or not an estimated system is automatically proper. ...

We study the following problem: given two words w and x, with jwj; jxj n, what is the size of the smallest context-free grammar G which generates exactly one of fw; xg? If jwj 6 = jxj, then we prove there exists a G separating w from x of size O(log log n), and this bound is best possible. If jwj = jxj, then we get an upper bound on the size of G of O(log n), and a lower bound of (logn loglog n).

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This paper answers three open questions concerning the generative power of some simple variants of context-free grammars regulated by context conditions. Specifically, it discusses the generative power of so-called contextfree semi-conditional grammars (which are random context grammars where permitting and forbidding sets are replaced with permitting and forbidding strings) where permitting an...

We show that, given a string s of length n, with constant memory and logarithmic passes over a constant number of streams we can build a context-free grammar that generates s and only s and whose size is within an O (