University of Marne-la-Vallée

About: University of Marne-la-Vallée is a based out in . It is known for research contribution in the topics: Estimator & Context (language use). The organization has 831 authors who have published 1855 publications receiving 55316 citations.

Episturmian words: shifts, morphisms and numeration systems

Abstract: Episturmian words, which include the Arnoux-Rauzy sequences, are infinite words on a finite alphabet generalizing the Sturmian words and sharing many of their same properties. This was studied in previous papers. Here we gain a deeper insight into these properties. This leads in particular to consider numerations systems similar to the Ostrowski ones and to give a matrix formula for computing the number of representations of an integer in such a system. We also obtain a complete answer to the question: if an episturmian word is morphic, which shifts of it, if any, also are morphic ?

Identifying satellites in nucleic acid sequences

Abstract: We present in this paper an algorithm for identifying satellites in DNA sequences. Satellites (simple, micro, or mini) are repeats in number between 30 and as many as l,OOO,OOO whose lengths vary between 2 and hundreds of base pairs and that appear, with some mutations, in tandem along the sequence. We concentrate here on short to moderately long (up to 30-40 base pairs) approximate tandem repeats where copies may differ up to e = 1520% from a consensus model of the repeating unit (implying individual units may vary by 2e from each other). The algorithm is composed of two parts. The first one consists of a filter that basically eliminates all regions whose probability of containing a satellite is less than one in lo4 when r = 10%. The second part realizes an exhaustive exploration of the space of all possible models for the repeating units present in the sequence. Thus it has the advantage over previous work of being able to report a consensus model, say m, of the repeated unit as well as the span of the satellite. The first phase was designed for efficiency and takes only O(n) time where n is the length of the sequence. The second phase was designed for sensitivity and takes time O(n -hl(e,k)) where k is the length of the repeating unit m, e = LekJ is the number of differences allowed between each repeat unit and the model m, and JJ(e,X-) is the maximum number of words that are not more than e differences from another word of length k. That is, M(e,I;) is the maximum size of an e-neighborhood of a string of length k. lites. Their span is large, up to a million bases, and the length of the repeated element varies greatly, anywhere from 5 to 100 base pairs. In the remaining, euchromatic region, of the chromosome the kinds of tandem repeats found are classifled as either micro or mini satellites, according to the length of the repeated element. Micro satellites are composed of short units, of 2 to 5 base pairs, in copy numbers typically around 100. Mini satellites on the other hand involve slightly longer repeats, around 15 base pairs, in clusters of variable sizes, comprising between 30 and 2000 elements. The functional role of satellites is not currently rmderstood, but they tend to be highly polymorphic, and thus at a minimum are very useful as genetic markers. Searching for these repeats in new DNA sequence is standard practice amongst sequence analysts. The few previous papers on this problem can be divided into three categories. The first concerns repeats that are exact (Karp [7] and Milosavljevic [lo]) or involve only two elements, that is, are of the form iiii where fi and 0 are two words, either at some maximum edit distance from one another (Landau [s]), or, more generally, having a highest scoring alignment under a real-valued scoring system (Kannan and Myers [5])Algorithms of the second group assume knowledge of the repeating unit or assume their length is short enough that all words of that length can be generated and fitted to the sequence (Delgrange [3], Fischetti [4] and Rivals [12]). Finally, the third kind of approach has none of the previous limitations but resorts to heuristics in order to find the repeats (Benson [l], Leung [S] [9] and Rivals [13]).

Assessing national and regional value creation

Abstract: In the knowledge economy, the value of corporations, organizations and individuals is directly related to their knowledge and intellectual capital. This does not only apply to organizations in the private or public sector but also to entire nations. If intangibles and intellectual capital are important to organizations, they are also important to the productivity and competitiveness of nations as a whole. The question we try to answer is how can we better understand the dynamics of intangibles on a national scale?

Uncertain Dynamical Systems in the Medium-Frequency Range

Abstract: This paper presents a novel probabilistic model of random uncertainties for dynamical system in the medium-frequency (MF) range. This approach combines a nonparametric probabilistic model of random uncertainties for the reduced matrix models in structural dynamics with a reduced matrix model adapted to the MF range. The theory is presented and the random energy matrix relating to a given MF band, its random trace, and its random eigenvalues are studied. A numerical example is presented allowing convergence properties and stability of random responses with respect to the bandwidth to be analyzed.