Visual link retrieval and knowledge discovery in painting datasets

Visual arts are of inestimable importance for the cultural, historic and economic growth of our society. One of the building blocks of most analysis in visual arts is to find similarity relationships among paintings of different artists and painting schools. To help art historians better understand visual arts, this paper presents a framework for visual link retrieval and knowledge discovery in digital painting datasets. Visual link retrieval is accomplished by using a deep convolutional neural network to perform feature extraction and a fully unsupervised nearest neighbor mechanism to retrieve links among digitized paintings. Historical knowledge discovery is achieved by performing a graph analysis that makes it possible to study influences among artists. An experimental evaluation on a database collecting paintings by very popular artists shows the effectiveness of the method. The unsupervised strategy makes the method interesting especially in cases where metadata are scarce, unavailable or difficult to collect.

     

A Conversational Approach to the Interaction With Web Services

The emerging standards for the specification of Web Services support the publication of the static interfaces of the operations they may execute. However, little attention is paid to the management of long-lasting interactions between the service providers and their consumers. Although this is not an issue in the case of "one-shot" services, it challenges the provision of services requiring the exchange of multiple messages between the business partners. In this article, we present a conversational model supporting the management of long-lasting interactions where several messages have to be exchanged before the service is completed. Our model aims at facilitating the consumers during the service invocation because in this way the establishment of short-term business relations can be simplified. To this extent, we provide a computational framework that can be exploited to manage a conversation between the consumer and the service provider. Our framework is inspired from the research developed in Computational Linguistics and in the area of Multi-Agent Systems to manage human-to-computer and agent-to-agent dialog. However, we employ techniques suitable to comply with the emerging Web Service standards and with the scalability requirements of the Internet.     

A Geometric Model of Multi-scale Orientation Preference Maps via Gabor Functions

In this paper we present a new model for the generation of orientation preference maps in the primary visual cortex (V1), considering both orientation and scale features. First we undertake to model the functional architecture of V1 by interpreting it as a principal fiber bundle over the 2-dimensional retinal plane by introducing intrinsic variables orientation and scale. The intrinsic variables constitute a fiber on each point of the retinal plane and the set of receptive profiles of simple cells is located on the fiber. Each receptive profile on the fiber is mathematically interpreted as a rotated Gabor function derived from an uncertainty principle. The visual stimulus is lifted in a 4-dimensional space, characterized by coordinate variables, position, orientation and scale, through a linear filtering of the stimulus with Gabor functions. Orientation preference maps are then obtained by mapping the orientation value found from the lifting of a noise stimulus onto the 2-dimensional retinal plane. This corresponds to a Bargmann transform in the reducible representation of the \(\text {SE}(2)=\mathbb {R}^2\times S^1\) group. A comparison will be provided with a previous model based on the Bargmann transform in the irreducible representation of the \(\text {SE}(2)\) group, outlining that the new model is more physiologically motivated. Then, we present simulation results related to the construction of the orientation preference map by using Gabor filters with different scales and compare those results to the relevant neurophysiological findings in the literature.     

On the performance of bandwidth and storage sharing in information-centric networks

Information Centric Network (ICN) proposals, have recently emerged to define new network architectures where content, and not its location, becomes the core of the communication model. Such new paradigms push data storage and delivery at network layer and are designed to cope with current Internet usage, mainly centered around content dissemination and retrieval.     

A review of the use of electro-thermal simulations for the analysis of heterostructure FETs

This paper deals with using device-level numerical simulations for the investigation of the electro-thermal behavior of a GaAs-based heterostructure FET. We show a way of dealing with the software/hardware limitations related with the huge disproportion between the electrically active region and the volume relevant to heat outflow. We study very wide simplified structures to obtain guidelines for building up a reduced grid and proper boundary conditions for the complete simulation of the electro-thermal behavior of the FET. As an application example, we use this approach to simulate the military standard (MIL-STD) method for the measurement of the thermal resistance of GaAs FETs, thus discussing its accuracy and limitations. We also show that in multi-finger structures a single channel temperature such as that obtained by electrical thermal resistance extraction techniques cannot satisfactorily describe the FET’s thermal behavior. Finally, we briefly dwell on a comparison between 2D and 3D simulations.     

A Comparative Analysis of Global and Local Processing of Hierarchical Visual Stimuli in Young Children (Homo sapiens) and Monkeys (Cebus apella).

Results obtained with preschool children (Homo sapiens) were compared with results previously obtained from capuchin monkeys (Cebus apella) in matching-to-sample tasks featuring hierarchical visual stimuli. In Experiment 1, monkeys, in contrast with children, showed an advantage in matching the stimuli on the basis of their local features. These results were replicated in a 2nd experiment in which control trials enabled the authors to rule out that children used spurious cues to solve the matching task. In a 3rd experiment featuring conditions in which the density of the stimuli was manipulated, monkeys' accuracy in the processing of the global shape of the stimuli was negatively affected by the separation of the local elements, whereas children's performance was robust across testing conditions. Children's response latencies revealed a global precedence in the 2nd and 3rd experiments. These results show differences in the processing of hierarchical stimuli by humans and monkeys that emerge early during childhood. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of pectinmethylesterase activity in presence of methanol during grape pomace storage

Methanol is an unwanted component in the production of spirit beverages. Its presence in grape pomace stored until distillation greatly affects the composition of the final product, which requires redistillation, modifying the aromatic characteristics of the distillate. Consequently, reduction of methanol, by controlling its formation during pomace storage, can increase the quality of grappa. The aim of this work was to monitor pectinmethylesterase activity during grape pomace storage, in order to identify its presence related to methanol release. The enzyme activity was detected during various storage times by spectrophotometric and electrophoretic methods. Results show that yeasts do not contribute to PME production. Moreover, by using paranitrophenyl acetate, a specific substrate for esterase, also as PME substrate, we demonstrate the presence of several enzymes hydrolysing ester bonds.     

Prediction of grape polyphenol astringency by means of a fluorimetric micro-plate assay

Previous works have demonstrated that astringency can be predicted on the basis of turbidity developed by polyphenol/mucin mixes. In the present study, a micro-plate assay, based on the ability of haze particles to screen the radiation emitted by a fluorescent compound (I%), is proposed for polyphenol/mucin reactivity estimation. Grape seed extract (GSE) solutions prepared in a range of physiochemical active concentrations (0.0–2.9 g/L) were reacted with mucin. A significant linear relationship (r = 0.99; p = 0.000) was found between turbidity (NTU) and I% values of GSE/mucin samples. Within the experimental range of phenolic samples, the CV value of I% determinations was always lower than 10%. The relationship between sensory and instrumental responses, as a function of phenolic solution characteristics, was investigated. Variations in phenol concentration and pH induce similar modifications of both the intensity of perceived astringency and I% values. A significant linear relationship (r = 0.98; p = 0.000) was found by relating sensory ratings to the relevant I% values.