Evaluating Learning and Interactions in a Multimedia Environment

An empirical study was undertaken to evaluate second language learning with a videodisc named Vi-Conte. The 78 subjects were post-secondary students and adults and belonged either to a control group, a video-control group or an experimental group. The research methodology is presented as well as analyses of learners' navigational patterns, strategies, gains in vocabulary items, changes in attitude and global evaluation of the videodisc. Suggestions for the development of adaptive learning environments are made based on these findings. This revised version was published online in July 2006 with corrections to the Cover Date.     

Substrate specificity of the lipase fromCandida parapsilosis

Substrate specificity of the acyltransferase activity of the lipase (EC 3.1.1.3) fromCandida parapsilosis CBS 604 was studied in aqueous media. The specificity toward both acid and alcohol parts of a large number of acylglycerols and aliphatic esters was investigated. This lipase showed a high activity in the presence of esters with long-chain fatty acids and particularly unsaturated fatty acids with acis-Δ9 double bond. It was observed that the activity profile depended not only on the alcohol part of the acyl ester, but also on the temperature of the reactant medium. The best lipid substrates had their melting point between −40 to +20°C, 14 to 18 carbon atoms in the acyl group and 1 to 4 carbon atoms in the alkyl group. The enzyme, defined as an acyltransferase in a previous paper, showed a high affinity for primary and secondary alcohols with a short carbon chain (1 to 5 carbon atoms) as acyl acceptors. The influence of free alcohols in the reactant medium on the hydrolysis and alcoholysis activities of the enzyme is discussed. Two phenomena seem to be involved, depending on the alcohol: competition with water for the acyltransfer reaction and lipid substrate dilution when the alcohol places at the oil/water interface.     

Generating shapes by analogies: An application to hearing aid design

3D shape modeling is a crucial component of rapid prototyping systems that customize shapes of implants and prosthetic devices to a patient’s anatomy. In this paper, we present a solution to the problem of customized 3D shape modeling using a statistical shape analysis framework. We design a novel method to learn the relationship between two classes of shapes, which are related by certain operations or transformation. The two associated shape classes are represented in a lower dimensional manifold, and the reduced set of parameters obtained in this subspace is utilized in an estimation, which is exemplified by a multivariate regression in this paper. We demonstrate our method with a felicitous application to the estimation of customized hearing aid devices.     

IncogniSense: An anonymity-preserving reputation framework for participatory sensing applications

Reputation systems are fundamental for assessing the quality of user contributions in participatory sensing. However, naively associating reputation scores to contributions allows adversaries to establish links between multiple contributions and thus de-anonymize users. We present the IncogniSense framework as a panacea to these privacy threats. IncogniSense utilizes periodic pseudonyms generated using blind signature and relies on reputation transfer between these pseudonyms. Simulations are used to analyze various reputation cloaking schemes that address the inherent trade-off between anonymity protection and loss in reputation. Our threat analysis confirms the robustness of IncogniSense and a prototype demonstrates that associated overheads are minimal.     

Personality and thinking style in different creative domains.

The crucial aspect of creativity in both personality and thinking style may be the ability or tendency to change within personality traits, such as, for example, moving between extraversion and introversion, and within thinking styles, such as moving between heuristic and algorithmic thinking. Such mobility is characteristic of the “complex” personality. On personality and thinking style tests, complexity would be expected to manifest itself in greater variability of responses to items measuring the same overall trait. This issue was investigated with 158 visual art, 136 music, and 309 psychology students. Art students (visual art and music students) showed greater complexity in conscientiousness than psychology and music students, respectively. Visual art students further showed a greater overall complexity (mean complexities across personality and thinking style) than psychology students did. A more traditional analysis revealed that visual art students were more neurotic, more open to experience and more inclined to heuristic thinking than psychology students do, whereas music students were more extraverted and more agreeable than visual art students were, and more inclined to heuristic thinking than psychology students were. Thus, it was possible to distinguish visual art students from music and psychology students by their personality and thinking style. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An extended actuator cylinder model: Actuator‐in‐actuator cylinder (AC‐squared) model

In this paper, the actuator‐in‐actuator cylinder (AC‐squared) model is presented. This model is an extension of the original actuator cylinder model of Madsen and is capable of modelling the effect of a two concentric actuation surfaces in 2D. The induced velocity at every point in the 2D field is affected by the force field acting on the two actuator cylinders. The equations are derived, and a model verification is performed using analytical solutions of flows, proof of flow equivalence, and using OpenFOAM calculations. Finally, the model is applied to different case studies, and the results are compared with a time‐dependent free wake vortex method.     

Investigation of steel corrosion in MX80 bentonite at 120°C

Corrosion experiments were performed on two metallic substrates, a ferritic–pearlitic steel (P285NH) and a ferritic one (Armco), in silicate environment during 30 days at 120°C. Corrosion products were characterized in terms of morphology (scanning electron microscope and transmission electron microscopy), composition (energydispersive X-ray spectroscopy) and structure (µ-Raman, selected area electron diffraction, X-ray absorption near edge structure). Results show a nanometric inner layer made of compact and adherent nanocrystallized magnetite with, locally a thickness up to several micrometers due to the metal microstructure. An outer layer of Fe-rich phyllosilicate, smectite and serpentine, more porous than the inner one and poorly adherent is observed around both the samples.     

Melt rheology of nanocomposites based on acrylic copolymer and cellulose whiskers

Nanocomposites based on poly(styrene-co-hexylacrylate) copolymer and cellulose whiskers as the nanosize filler were prepared by in situ miniemulsion polymerization and their melt rheological behaviours were investigated under dynamic shear conditions. The effects of γ-methacryloxypropyl triethoxysilane (MPS) content along with the whisker loading were explored. In the absence of whiskers, a transition from a liquid- to a solid-like behaviour was observed when the polymer was synthesized in the presence of MPS. When cellulose nanofiller was added, the storage modulus G′ and the dynamic viscosities η of the nanocomposites increased monotonically with whisker content and the resulting materials displayed a solid-like behaviour. Above 2 wt.%. loading, a percolated interconnected whisker-whisker network is built up, producing a jump in the storage modulus and strong shear-thinning behaviour of the viscosity. However, as the nanocomposites were prepared in the presence of 3% of MPS, no enhancement nor in the storage modulus nor in the viscosity was observed up to 5 wt.%. of whisker loading. Such a phenomenon was ascribed to inhibition of build-up of the whisker network. The non-linear viscoelastic behaviour of the nanocomposites was also investigated and analysed in terms of the breakdown of different networks, namely the filler-filler and the polymer-filler networks.