FIRE: fractal indexing with robust extensions for image databases

As already documented in the literature, fractal image encoding is a family of techniques that achieves a good compromise between compression and perceived quality by exploiting the self-similarities present in an image. Furthermore, because of its compactness and stability, the fractal approach can be used to produce a unique signature, thus obtaining a practical image indexing system. Since fractal-based indexing systems are able to deal with the images in compressed form, they are suitable for use with large databases. We propose a system called FIRE, which is then proven to be invariant under three classes of pixel intensity transformations and under geometrical isometries such as rotations by multiples of /spl pi//2 and reflections. This property makes the system robust with respect to a large class of image transformations that can happen in practical applications: the images can be retrieved even in the presence of illumination and/or color alterations. Additionally, the experimental results show the effectiveness of FIRE in terms of both compression and retrieval accuracy.     

An experimental pilot study of tacalcitol activities during modulation of parakeratotic skin features

Establishing guidelines and experimental models preclinical and clinical evaluations of new agents for treatment, and/or prevention of human diseases has become a task of crucial importance. Psoriasis is such one disease holding great interest for dermatology owing to its high rate of incidence and complexity of treatment. However the absence of psoriatic lesions in animals and the inability to induce them, calls for experimental techniques both in vitro and in vivo. The purpose of this study was to evaluate experimentally the effects of tacalcitol on cell proliferation and differentiation process. Thereafter a human pilot study on psoriatic patients has been developed.     

Virtual images for similarity retrieval in image databases

We introduce the virtual image, an iconic index suited for pictorial information access in a pictorial database, and a similarity retrieval approach based on virtual images to perform content-based retrieval. A virtual image represents the spatial information contained in a real image in explicit form by means of a set of spatial relations. This is useful to efficiently compute the similarity between a query and an image in the database. We also show that virtual images support real-world applications that require translation, reflection, and/or rotation invariance of image representation     

Influence of oxygen on the sputtering of aluminum oxide for the surface passivation of crystalline silicon

While sputtering has been shown to be capable of depositing aluminum oxide suitable for surface passivation, the mechanisms for this are yet to be firmly established and its potential realized. In this paper, we investigate the relationships between the oxygen in the sputtering process to the resulting composition of the deposited film and the surface passivation obtained. We find that surface passivation is not strongly dependent on the bulk composition of the film. Instead the results indicate that the interfacial silicon oxide layer that forms after annealing between the aluminum oxide film and the silicon is a much more important factor; it is this combined structure of aluminum oxide, silicon oxide and silicon that is crucial for obtaining negative charges and excellent surface passivation.     

Microstructural and mechanical changes by chemical ageing of glazed ceramic surfaces

In the present work, several ceramic tiles, characterised by different glazes, were considered in order to define the role played by the glassy and crystalline phases on the leaching mechanisms and the deterioration of the mechanical properties. The glazed working surfaces were subjected to chemical attack by using a strong basic solution and the chemical analysis of the leached solutions was performed. Before and after the chemical attack, the glazed surfaces of the samples were analysed from both the microstructural and mechanical point of view. In this context, the microstructure was observed by SEM and analysed by X-ray diffraction. In order to define other possible changes, roughness measurements, Vickers hardness and micro-scratch tests were also performed.The results made it possible to deepen the understanding of the mechanisms of elements release caused by the chemical attack and their implications on microstructural and mechanical degradation of the working surface of glazed ceramic tiles.     

Sintered esseneite–wollastonite–plagioclase glass–ceramics from vitrified waste

Dense sintered esseneite–wollastonite–plagioclase glass–ceramics have been successfully prepared from a vitrified mixture of important inorganic waste (Bayer process red mud, fly ash from lignite combustion and residues from the polishing of porcelain stoneware tiles). The enhanced nucleation activity of fine glass powders, favoured by particular oxidation conditions, caused a substantial crystallisation, even in the case of very rapid thermal treatments at 900 °C, which led to remarkable mechanical properties (bending strength and Vickers micro-hardness exceeding 130 MPa and 7 GPa, respectively) and a promising chemical durability.