Convolutional Neural Networks Via Node-Varying Graph Filters

Convolutional neural networks (CNNs) are being applied to an increasing number of problems and fields due to their superior performance in classification and regression tasks. Since two of the key operations that CNNs implement are convolution and pooling, this type of networks is implicitly designed to act on data described by regular structures such as images. Motivated by the recent interest in processing signals defined in irregular domains, we advocate a CNN architecture that operates on signals supported on graphs. The proposed design replaces the classical convolution not with a node-invariant graph filter (GF), which is the natural generalization of convolution to graph domains, but with a node-varying GF. This filter extracts different local features without increasing the output dimension of each layer and, as a result, bypasses the need for a pooling stage while involving only local operations. A second contribution is to replace the node-varying GF with a hybrid node-varying GF, which is a new type of GF introduced in this paper. While the alternative architecture can still be run locally without requiring a pooling stage, the number of trainable parameters is smaller and can be rendered independent of the data dimension. Tests are run on a synthetic source localization problem and on the 20NEWS dataset.Comment: Submitted to DSW 2018 (IEEE Data Science Workshop

Nata organisms: an overview on the fermentative microbial ecosystem

Publicado em "Abstracts of papers - American Chemical Society", vol. 245The Acetobacter and Gluconacetobacter genus (both from the Acetobacteraceae family) are the most notable acetic acid producers, their intermediate metabolites being exploited biotechnologicaly for the production of vinegar, Kombucha, cocoa and nata de coco. Extensive efforts are being made to better understand the dynamic interplay of microbial populations during fermentation processes, with ample literature existing on virtually every food product currently being consumed. In the case of nata de coco, Gluconacetobacter strains have been found to play a key role in cellulose production. Despite abundant literature with isolated cellulose−producing strains, little work has been done in analysing population dynamics of the microbial communities. This presentation will address the microbial interplay in the production of nata de coco, with an overview of the taxonomy of the major acetic acid strains involved. An overview on the efforts and potential implications of upgrading nata de coco production through biotechnology will also be addressed

Bacterial NanoCellulose: what future?

Acetic acid bacteria (AAB) have been used in various fermentation processes. Of several ABB, the bacterial nanocellulose (BNC) producers, notably Komagataeibacter xylinus, appears as an interesting species, in large part because of their ability in the secretion of cellulose as nano/microfibrils. In fact, BNC is characterized by a native nanofibrillar structure, which may outperform the currently used celluloses in the food industry as a promising novel hydrocolloid additive. During the last couple of years, a number of companies worldwide have introduced some BNC-based products to the market. The main aim of this editorial is to underline the BNC potentials.info:eu-repo/semantics/publishedVersio

Bacterial cellulose from lab to market

Book of Abstracts of CEB Annual Meeting 2017Bacterial nanocellulose (BNC) is a nanofibrilar exopolysaccharide synthesized by certain Gram-negative, obligate aerobic, acetic acid bacteria, the Komagataeibacter genus being the most important due to the high cellulose yield obtained. The unique properties of this biopolymer have supported a wide range of potential applications, in human and veterinary medicine, odonthology, pharmaceutical industry, acoustic and filter membranes, biotechnological devices and in the food and paper industry. The largescale production of BNC, through advanced biotechnology has eluded many researches. Historical attempts but on low volume and high-value (mostly for biomedical applications) production can be traced back to the 90s. This presentation will show the main work with BNC by the Funcarb group. Examples of these studies will include the use of BNC in biomedical and food applications. Finally, an overview on the main efforts towards the production of BNC at large scale and potential markets will also be presented.info:eu-repo/semantics/publishedVersio