A multiple layer model to compare RNA secondary structures

International audienceWe formally introduce a new data structure, called MiGaL for ``Multiple Graph Layers'', that is composed of various graphs linked together by relations of abstraction/refinement. The new structure is useful for representing information that can be described at different levels of abstraction, each level corresponding to a graph. We then propose an algorithm for comparing two MiGaLs. The algorithm performs a step-by-step comparison starting with the most ``abstract'' level. The result of the comparison at a given step is communicated to the next step using a special colouring scheme. MiGaLs represent a very natural model for comparing RNA secondary structures that may be seen at different levels of detail, going from the sequence of nucleotides, single or paired with another to participate in a helix, to the network of multiple loops that is believed to represent the most conserved part of RNAs having similar function. We therefore show how to use MiGaLs to very efficiently compare two RNAs of any size at different levels of detail

Capitalizing on Information Organization and Information Visualization for a New-Generation Catalogue

Subject searching is difficult with traditional text-based online public access library catalogues (OPACs), and the next-generation discovery layers are keyword searching and result filtering tools that offer little support for subject browsing. Next-generation OPACs ignore the rich network of relations offered by controlled subject vocabulary, which can facilitate subject browsing. A new generation of OPACs could leverage existing information-organization investments and offer online searchers a novel browsing and searching environment. This is a case study of the design and development of a virtual reality subject browsing and information retrieval tool. The functional prototype shows that the Library of Congress subject headings (LCSH) can be shaped into a useful and usable tree structure serving as a visual metaphor that contains a real world collection from the domain of science and engineering. Formative tests show that users can effectively browse the LCSH tree and carve it up based on their keyword search queries. This study uses a complex information-organization structure as a defining characteristic of an OPAC that goes beyond the standard keyword search model, toward the cutting edge of online search tools.published or submitted for publicatio

The Gapped-Factor Tree

International audienceWe present a data structure to index a specific kind of factors, that is of substrings, called gapped-factors. A gapped-factor is a factor containing a gap that is ignored during the indexation. The data structure presented is based on the suffix tree and indexes all the gapped-factors of a text with a fixed size of gap, and only those. The construction of this data structure is done online in linear time and space. Such a data structure may play an important role in various pattern matching and motif inference problems, for instance in text filtration

S-adic characterization of minimal ternary dendric shifts

Dendric shifts are defined by combinatorial restrictions of the extensions of the words in their languages. This family generalizes well-known families of shifts such as Sturmian shifts, Arnoux-Rauzy shifts and codings of interval exchange transformations. It is known that any minimal dendric shift has a primitive S-adic representation where the morphisms in S are positive tame automorphisms of the free group generated by the alphabet. In this paper we investigate those S-adic representations, heading towards an S-adic characterization of this family. We obtain such a characterization in the ternary case, involving a directed graph with 2 vertices

Implicit Representations of the Human Intestines for Surgery Simulation

International audienceIn this paper, we propose a modeling of the intestines by implicit surfaces for abdominal surgery simulation. The difficulty of such a simulation comes from the animation of the intestines. As a matter of fact, the intestines are a very long tube that is not isotropically elastic, and that bends over itself at various spots, creating multiple self-contacts. We use a multiple component model for the intestines: The first component is a mechanical model of their axis; the second component is a specific sphere-based model to manage collisions and self-collisions; and the third component is a skinning model to define their volume. This paper focuses on the better representation for skinning the intestines. We compare two implicit models: Surfaces defined by point-skeletons and convolution surfaces. A direct application of this simulation is the training of a typical surgical gesture to move apart the intestines in order to reach certain areas of the abdomen

L’efficacité d’une intervention orthopédagogique sur le transfert des apprentissages en lecture : étude de trois cas d’élèves en difficulté

Many authors have shown that abilities related to decoding, acquired through intensive reading interventions, did not transfer to the general ability to read text. This study aimed to test the effectiveness of a remediating reading intervention based on explicit and strategic teaching regarding transfer of knowledge in Grade 2 and 3 students experiencing reading difficulties. A multiple baseline design allowed to measure participants’ (N = 3) progress during the four weeks remediating intervention. The results show how the intervention fostered learning and transfer of knowledge for the students involved in the research.Certains apprentissages, réalisés à l’intérieur de séances rééducatives, ne se transfèrent pas à la compétence à lire des élèves en difficulté lors de situations authentiques de lecture. Cette étude a donc vérifié l’efficacité d’une intervention orthopédagogique basée sur l’enseignement explicite et stratégique en lecture sur le transfert d'habiletés d’identification de mots en situation authentique de lecture chez des élèves en difficulté du primaire. Un devis expérimental à cas unique a permis de mesurer les progrès des participants (N=3) qui ont bénéficié d’une rééducation pendant quatre semaines. Les résultats montrent comment l’intervention a favorisé ou non l’apprentissage et le transfert pour ces élèves.

Tutorat par les pairs pour des étudiants en situation de handicap non visible : la perception des tuteurs

Cet article a pour objectif de décrire un programme de tutorat à l’Université du Québec à Montréal et les perceptions des tuteurs à ce propos. Le programme s’adresse à des étudiants-tuteurés en situation de « handicap non visible » et cible le renforcement de leurs stratégies d’apprentissage. Cette étude exploratoire, auprès de sept tuteurs impliqués dans ce programme, présente les motivations, la satisfaction et le rôle de ces derniers, leurs perceptions de la formation offerte sur le tutorat, les activités réalisées et les difficultés rencontrées. Les données ont été obtenues à l’aide d’une entrevue individuelle et d’un questionnaire. Les résultats indiquent que les tuteurs semblent satisfaits de leur expérience qui en retour semble contribuer à leur développement professionnel. Toutefois, les tuteurs proposent de mettre en place des mesures de supervision plus soutenues lors de la session universitaire. Ils relèvent des difficultés associées à la motivation des tuteurés et à la gestion des rencontres. Ils soulignent aussi des problèmes à dissocier l’apprentissage des stratégies d’études et la relation personnelle avec les étudiants tuteurés. La discussion propose plusieurs recommandations à l’intention des universités utilisant le tutorat comme dispositif dans l’aide aux étudiants en situation de handicap.This paper aims to describe a tutoring program at the University of Quebec in Montreal and to assess the tutors’ appreciations of the program in question. The latter was designed for students-tutees with “invisible handicap” and was intended to improve their study strategies. In this exploratory study, the seven tutors involved describe their motivation, their satisfaction, their role, their perceptions of the actual tutoring training, the activities completed and the challenges encountered. The data was obtained using individual interviews and questionnaires. The results reveal that the tutors seem satisfied with their experience, which in turn appears to have contributed to their professional development. Nevertheless, tutors suggest more supervision activities during the academic session as they came across challenges regarding the tutees’ motivation and managing meetings. The tutors also pointed out issues related to distinguishing learning from study strategies and to the relationships developed with the tutees. The paper closes on recommendations to universities wishing to use tutoring to help students with disabilities