Sparsely Connected Autoassociative Lattice Memories with an Application for the Reconstruction of Color Images

Sparsely connected autoassociative lattice memories (SCALMs) are very general models defined on complete lattices, a mathematical structure which is obtained by imposing some ordering on a set. They are computationally cheaper and mathematically simpler than ??traditional?? models and other memories such as the original autoassociative morphological memories (AMMs) of Ritter and Sussner because they only compute maximums and minimums. This paper provides theoretical results on SCALMs defined on a general complete lattice as well as an application of these memories for the storage and recall of color images. Precisely, we characterize the recall phase of SCALMs in terms of their fixed points. Then, we show that any endomorphic lattice polynomial??a concept that generalizes the notion of lattice polynomial of Birkhoff??on the fundamental memory set represents a fixed point of the SCALMs. Also, we discuss the relationship between SCALMs and the original AMMs. Finally, we provide some experimental results on the performance of SCALMs, defined on different color lattices, for the reconstruction of color images corrupted by either Gaussian or impulsive noise.     

A mobile-based solution for supporting end-users in the composition of services

Currently, technologies and applications evolve to create eco-systems made up of a myriad of heterogeneous and distributed services that are accessible anytime and anywhere. Even though these services can be used individually, it is their coordinated and combined usage what provide an added value to end-users. In addition, user’s wide adoption of mobile devices for daily activities have fostered a shift in the role played by end-users towards Internet data and services. However, existing solutions to service composition are not targeted to ordinary end-users. More easy-to-use tools have to be offered to end-users to make sure that they are successfully accepted and used by them. To this end, the work presented in this paper supports end-users in the creation of service compositions by using mobile devices. We present a Domain Specific Visual Language (DSVL) for end-users that allows them to create service compositions. A tool specifically designed for mobile devices supports this DSVL.     

Evaluation of the influence of post welding heat treatments on microstructure and mechanical properties of API 5L X70Q weld joints*

Steels that meet the API 5L standard are employed in pipeline construction, and there is considerable interest in those of higher strength, such as grade API 5L X70Q. There have nevertheless been few studies relating to seamless pipes. During installation, the pipes may be welded with covered electrodes (SMAW) and may optionally undergo inductive heating for adjustment to the topography of the terrain, processes that may alter the microstructure of the joints. In this work, welded joints were obtained by the SMAW process, from seamless pipe of grade API 5L X70Q. The joints were submitted to post-weld heat treatments at temperatures of 920 and 600 °C. Tensile, Charpy impact and microhardness tests were carried out, besides metallographic characterization in specimens of base metal and in the joints, as-welded and after the heat treatments. Heat treatment at 920 °C promoted formation of a ferrite/pearlite structure, with consequent reduction in the mechanical strength of the joints to values below those specified for grade X70Q. However, heat treatment at 600 °C proved to be beneficial owing to the reduction of the volume fraction of the martensite/austenite and martensite-austenite-bainite constituents, without significantly reducing the mechanical strength and with a relative gain in impact toughness in the heat-affected zone and in the fusion zone (FZ).     

Numerical analysis of step-index channel waveguides designed with a formally-equivalent separable index profile

Abstract

A numerical test is proposed to evaluate the separability of a modal field supported by an inverted-rib waveguide, which was properly designed to make its general non-separable index profile formally equivalent to a separable one. The possibility of obtaining such a separable equivalent profile leads to much more simplicity in the design of channel waveguides and other more complicated integrated devices, since it is possible to obtain a quasi-exact solution to the modal propagation problem by using the effective index method. The influence of the different waveguide parameters on the field separability is also investigated in order to evaluate the flexibility of the design method.     

Citation increments between collaborating countries

International collaboration enhances citation impact. Collaborating with a country increments the citations received from it. But some collaborating countries provide greater increments in this sense than others, and likewise some countries receive greater increments from their partner countries than others. We observed a certain tendency for these increments to be lower in countries with greater impacts. Also, all the countries studied had higher Domestic Impacts as a result of collaborating, although this increment was less than that obtained from other countries. Finally, there were differences in the behaviour of the countries between the various scientific disciplines, with the effects being greatest in Social Sciences, followed by Engineering.     

The effect of information and communication technologies on creativity in collaborative design

This study compares the degree of creativity of forty-two conceptual designs proposed as solutions to two innovative design problems developed in face-to-face and virtual collaborative environments. The solutions obtained were evaluated by three experts applying the Moss metric, which considers the level of usefulness and the level of unusualness. The average values and the trends of the data were obtained, and an analysis of the variance was also performed to determine whether the environment influences the degree of creativity. The results show that it cannot be proved that the level of creativity is influenced by working face-to-face or virtually, that is, whether information and communication technologies are used or not has no effect on the final result.     

Isothermal close space sublimation for II-VI semiconductor filling of porous matrices

ABSTRACT: Isothermal close space sublimation, a simple and low cost physical vapor transport technique, was used to infiltrate ZnTe and CdSe semiconductors in porous silicon (PS). The structure of the embedded materials was determined by x-ray diffraction analysis while Rutherford backscattering spectra allowed determining the composition profiles of the samples. In both cases, it was found a constant composition of the II-VI semiconductors throughout the porous layer down to the substrate. The infiltration of the pores is also verified qualitatively by reflectance measurements. Resonance Raman scattering of the ZnTe samples indicates that this semiconductor grows in nanostructured form inside the pores. Results presented in this paper suggest that Isothermal close-space sublimation (ICSS) is a promising technique for the conformal growth of II-VI semiconductor in porous silicon.