Cationic reactions in the melt

Summary Reactions in the melt between polystyrene and ethylene propylene co- and terpolymers were studied in the presence of anhydrous AlCl₃ using the mixing chamber of a Brabender Plastograph as the reactor. Various concurrent reactions have been identified, i.e., grafting, degradation, crosslinking, etc., the rates of which depend on the nature of the polymers and of the AlCl₃ added. Grafting is extensive, 40–50%, and the composition of the grafts is close to that of the charge.     

Physiological and subjective evaluation of a human-robot object hand-over task

In the context of task sharing between a robot companion and its human partners, the notions of safe and compliant hardware are not enough. It is necessary to guarantee ergonomic robot motions. Therefore, we have developed Human Aware Manipulation Planner (Sisbot et al., 2010), a motion planner specifically designed for human–robot object transfer by explicitly taking into account the legibility, the safety and the physical comfort of robot motions. The main objective of this research was to define precise subjective metrics to assess our planner when a human interacts with a robot in an object hand-over task. A second objective was to obtain quantitative data to evaluate the effect of this interaction. Given the short duration, the “relative ease” of the object hand-over task and its qualitative component, classical behavioral measures based on accuracy or reaction time were unsuitable to compare our gestures. In this perspective, we selected three measurements based on the galvanic skin conductance response, the deltoid muscle activity and the ocular activity. To test our assumptions and validate our planner, an experimental set-up involving Jido, a mobile manipulator robot, and a seated human was proposed. For the purpose of the experiment, we have defined three motions that combine different levels of legibility, safety and physical comfort values. After each robot gesture the participants were asked to rate them on a three dimensional subjective scale. It has appeared that the subjective data were in favor of our reference motion. Eventually the three motions elicited different physiological and ocular responses that could be used to partially discriminate them.     

Broken symmetries in a location-invariant word recognition network

We studied the feedforward network proposed by Dandurand et al. (2010), which maps location-specific letter inputs to location-invariant word outputs, probing the hidden layer to determine the nature of the code. Hidden patterns for words were densely distributed, and K-means clustering on single letter patterns produced evidence that the network had formed semi-location-invariant letter representations during training. The possible confound with superseding bigram representations was ruled out, and linear regressions showed that any word pattern was well approximated by a linear combination of its constituent letter patterns. Emulating this code using overlapping holographic representations (Plate, 1995) uncovered a surprisingly acute and useful correspondence with the network, stemming from a broken symmetry in the connection weight matrix and related to the group-invariance theorem (Minsky & Papert, 1969). These results also explain how the network can reproduce relative and transposition priming effects found in humans.     

A Set of Successive Job Allocation Models in Distributed Computing Infrastructures

The growing number of scientific computation-intensive applications calls for an efficient utilization of large-scale, potentially interoperable distributed infrastructures. Parameter sweep applications represent a large body of workflows. While the principle of workflows is easy to conceive, their execution is very complex and no universally accepted solution exists. In this paper we focus on the resource allocation challenges of parameter study jobs in distributed computing infrastructures. To cope with this NP-hard problem and the high uncertainty present in these systems, we propose a series of job allocation models that helps refining and simplifying the problem complexity. In this way we present some special cases that are polynomial and show how more complex scenarios can be reduced to these models. It is known from practice that a small number of job sizes improves the result of job allocation, therefore we state a hypothesis relying on this fact in one of our models. Unfortunately, the reduction of the general problem (using K-means clustering) did not help, and thus the hypothesis has proved to be false. In the future, we shall look for clustering techniques which fit this goal better.     

Exploratory study of introducing HPC to non-ICT researchers: institutional strategy is possibly needed for widespread adaption

The Journal of Supercomputing - Machine learning algorithms are becoming more and more useful in many fields of science, including many areas where computational methods are rarely used....     

Coupling solvers with model transformations to generate explorable model sets

Software and Systems Modeling - Model transformation is an effective technique to produce target models from source models. Most transformation approaches focus on generating a single target model...     

Toward the link between structural and mechanical properties of fiber aggregates in paper materials

Journal of Materials Science - Mechanical properties of fiber-based materials, such as paper, are governed by the heterogeneous microstructure induced by the formation process. For example, in...     

Response of Thermo- Electro-Magneto Semiconductor Elastic Medium to Photothermal Excitation Process with Thomson Influence

Silicon - The effect of Thomson heating of semiconductor medium is studied. Analytical discussions are made in the presence of thermoelectricity theory and magnetic field in context of Photothermal...