Integrating load balancing and locality in the parallelization of irregular problems

An irregular problem models the evolution of a system where several elements are irregularly distributed in a domain. The evolution modifies this distribution in a way that cannot be foreseen and the behavior of each element depends upon the elements close to it according to a problem dependent relation. Starting from a hierarchical representation of the domain, we define a parallelization methodology that includes a load balancing strategy that preserves this locality property and a strategy to collect information distributed onto the processing nodes.     

Planar packing of trees and spider trees

In [A. García, C. Hernando, F. Hurtado, M. Noy, J. Tejel, Packing trees into planar graphs, J. Graph Theory (2002) 172-181] García et al. conjectured that for every two non-star trees there exists a planar graph containing them as edge-disjoint subgraphs. In this paper we prove the conjecture in the case in which one of the trees is a spider tree.     

SVD-Based Techniques for Zero-Padded Block Transmission Over Fading Channels

In this paper, the performance of filter bank transceivers in the presence of a dispersive time-variant channel is investigated. It is well known that filter bank transceivers can be adapted to the channel transfer function to yield intersymbol interference (ISI) cancellation. When the channel is time variant, several problems arise, since the transceiver should be changed whenever the channel evolves. In this paper, we will allow both the transmitter and the receiver to change and satisfy the interference-free condition, under the assumption of a zero-padded block transmission. In this case, the optimum transmitter-receiver pair can be computed by using a singular value decomposition (SVD) of the channel matrix. A fast receiver adaptation based on SVD tracking is presented. Simulation results show that minimum performance loss with respect to the optimum receiver can be achieved for our reduced complexity receiver     

Visualizing the structure and bridges of the intellectual property management and strategy literature: a document co-citation analysis

This article uses document co-citation analysis to objectively explore the underlying structure of the intellectual property research domain, taken from a managerial and strategic standpoint. The goal of this study is identifying its main research areas, understanding its current state of development and suggesting potential future directions, by analyzing the co-citations from 181 papers published between 1992 and 2011 in the most influential academic journals. Five main clusters have been identified, mapped, and labeled as follows: Economics of patent system, technological and institutional capabilities, university patenting, intellectual property exploitation, and division of labor. Their most active areas on this topic, and the most influential and co-cited papers have been identified and described. Also, intra- and inter-cluster knowledge base diversity has been assessed by using indicators stemming from the domains of information theory and biology. A t test has been performed to assess the significance of the inter-cluster diversity. The knowledge bases of these five clusters are significantly diverse, this meaning that they are five co-existing paradigms.     

Study of liquid sloshing: numerical and experimental approach

In this paper, sloshing phenomenon in a rectangular tank under a sway excitation is studied numerically and experimentally. Although considerable advances have occurred in the development of numerical and experimental techniques for studying liquid sloshing, discrepancies exist between these techniques, particularly in predicting time history of impact pressure. The aim of this paper is to study the sloshing phenomenon experimentally and numerically using the Smoothed Particle Hydrodynamics method. The algorithm is enhanced for accurately calculating impact load in sloshing flow. Experiments were conducted on a 1:30 scaled two-dimensional tank, undergoing translational motion along its longitudinal axis. Two different sloshing flows corresponding to the ratio of exciting frequency to natural frequency were studied. The numerical and experimental results are compared for both global and local parameters and show very good agreement.     

Effect of chemical treatments on the mechanical and thermal behaviour of okra (Abelmoschus esculentus) fibres

The effect of a number of chemical treatments on the mechanical (tensile), thermal (FTIR, TGA) and water absorption properties of okra (Abelmoschus esculentus) fibres has been studied. These included: bare scouring of the fibres; bleaching (pure, and followed by acetylation or alkalisation); pure acetylation; sodium sulphite; sulphuric acid with potassium permanganate. Tensile properties of the fibres were studied using Weibull statistics and correcting the values obtained by the void content measured from SEM images. A separate set of SEM images allowed also characterising their failure mode. The general trend of the results shows some decrease in mechanical properties by all treatments, although the effect is partially concealed by the high variation of fibre dimensions and the relative variation of void content. Fracture surfaces present an increased level of twisting as an effect of chemical modification resulting in reduced adhesion force between the fibrils, though seldom in their physical separation. Treatments involving acetylation result in limited fibre degradation, whilst bleaching, scouring and particularly permanganate treatment, though mechanically damaging for the fibres, have lower influence on their thermal behaviour. Water absorption profile is significantly improved by all applied treatments.     

A comparative study of different DNA barcoding markers for the identification of some members of Lamiacaea

The objective of the present work is to evaluate the efficacy of a DNA barcoding approach as a tool for the recognition of commercial kitchen spices belonging to the Lamiaceae family that are usually sold as enhancers of food flavor. A total of 64 spices samples, encompassing six different genera (i.e. Mentha, Ocimum, Origanum, Salvia, Thymus and Rosmarinus) were processed with a classical DNA barcoding approach by amplifying and sequencing four candidate barcode regions (rpoB, rbcL, matK and trnH-psbA) with universal primers. Results suggest that the non-coding trnH-psbA intergenic spacer is the most suitable marker for molecular spices identification followed by matK, with interspecific genetic distance values ranging between about 0% to 7% and 0% to 5%, respectively. Both markers were almost invariably able to distinguish spices species from closest taxa with the exclusion of samples belonging to the genus Oregano. Moreover, in a context of food traceability the two markers are useful to identify commercial processed spice species (sold as dried plant material). We also evaluated the potential benefits of a multilocus barcode approach over a single-marker and although the most suitable combination was the matK + trhH-psbA, the observed genetic distances values were very similar to the discriminatory performance of the trnH-psbA. Finally, this preliminary work provide clear evidences that the efficacy of a DNA barcoding approach to the recognition of commercial spices is biased by the occurrence of taxonomic criticisms as well as traces of hybridization events within the family Lamiaceae. For this reason, to better define a more practical and standardized DNA barcoding tool for spices traceability, the building of a dedicated aromatic plants database in which all species and cultivars are described (both morphologically and molecularly) is strongly required.