EUSBoost: Enhancing ensembles for highly imbalanced data-sets by evolutionary undersampling

Classification with imbalanced data-sets has become one of the most challenging problems in Data Mining. Being one class much more represented than the other produces undesirable effects in both the learning and classification processes, mainly regarding the minority class. Such a problem needs accurate tools to be undertaken; lately, ensembles of classifiers have emerged as a possible solution. Among ensemble proposals, the combination of Bagging and Boosting with preprocessing techniques has proved its ability to enhance the classification of the minority class.In this paper, we develop a new ensemble construction algorithm (EUSBoost) based on RUSBoost, one of the simplest and most accurate ensemble, which combines random undersampling with Boosting algorithm. Our methodology aims to improve the existing proposals enhancing the performance of the base classifiers by the usage of the evolutionary undersampling approach. Besides, we promote diversity favoring the usage of different subsets of majority class instances to train each base classifier. Centered on two-class highly imbalanced problems, we will prove, supported by the proper statistical analysis, that EUSBoost is able to outperform the state-of-the-art methods based on ensembles. We will also analyze its advantages using kappa-error diagrams, which we adapt to the imbalanced scenario.     

Dynamic classifier selection for One-vs-One strategy: Avoiding non-competent classifiers

The One-vs-One strategy is one of the most commonly used decomposition technique to overcome multi-class classification problems; this way, multi-class problems are divided into easier-to-solve binary classification problems considering pairs of classes from the original problem, which are then learned by independent base classifiers.The way of performing the division produces the so-called non-competence. This problem occurs whenever an instance is classified, since it is submitted to all the base classifiers although the outputs of some of them are not meaningful (they were not trained using the instances from the class of the instance to be classified). This issue may lead to erroneous classifications, because in spite of their incompetence, all classifiers' decisions are usually considered in the aggregation phase.In this paper, we propose a dynamic classifier selection strategy for One-vs-One scheme that tries to avoid the non-competent classifiers when their output is probably not of interest. We consider the neighborhood of each instance to decide whether a classifier may be competent or not. In order to verify the validity of the proposed method, we will carry out a thorough experimental study considering different base classifiers and comparing our proposal with the best performer state-of-the-art aggregation within each base classifier from the five Machine Learning paradigms selected. The findings drawn from the empirical analysis are supported by the appropriate statistical analysis.     

Hydrothermal synthesis and study of an inorganic-organic hybrid vanadate of a nickel(II) coordination complex with pyrazine, Ni3(C4H4N2)3(V8O23)

The three-dimensional hybrid compound Ni₃(C₄H₄N₂)₃(V₈O₂₃) has been synthesized by mild hydrothermal methods under autogenous pressure at 170 °C. The structure of the phase is stable until 380 °C. The removal of the pyrazine molecules from the structure induces its collapse. The IR spectrum shows the vibration modes of the pyrazine molecule and those of the [VO₄]³⁻ groups. A UV-visible spectrum shows the characteristic bands of the Ni(II) d⁸-high-spin cation in a slightly distorted octahedral coordination. Magnetic measurements indicate the existence of antiferromagnetic interactions that can be fitted with a chain model to give g = 2.31, J/k = −5.3, and zJ′/k = −5.5.     

Similarity measures,penalty functions,and fuzzy entropy from new fuzzy subsethood measures

In this study, we discuss a new class of fuzzy subsethood measures between fuzzy sets. We propose a new definition of fuzzy subsethood measure as an intersection of other axiomatizations and provide two construction methods to obtain them. The advantage of this new approach is that we can construct fuzzy subsethood measures by aggregating fuzzy implication operators which may satisfy some properties widely studied in literature. We also obtain some of the classical measures such as the one defined by Goguen. The relationships with fuzzy distances, penalty functions, and similarity measures are also investigated. Finally, we provide an illustrative example which makes use of a fuzzy entropy defined by means of our fuzzy subsethood measures for choosing the best fuzzy technique for a specific problem.     

Identification of mannose moieties in N- and O-linked oligosaccharides of the primordial germ cells of Xenopus embryos

The presence of mannose (Man) in the glycoconjugates of primordial germ cells (PGCs) of Xenopus embryos was elucidated by lectin histochemistry with Concanavalin A (Con A) and snowdrop (Galanthus nivalis) bulb lectin (GNA), in combination with deglycosylative pretreatments: beta-elimination, which removes O-linked oligosaccharides, and incubation with Peptide N glycosidase F (PNGase F), which removes N-linked glycan chains. In addition, histochemistry with Con A, which binds to Man and glucose (Glc), was also performed after glucose-oxidase incubation, which converts Glc into gluconic acid, and GNA was carried out after acid hydrolysis, which removes terminal sialic acid (NeuAc) moieties. PGCs were analyzed during their migration over the mesentery until the genital ridge, and after colonization of this gonad anlage. The results showed that for both lectins: (1) the PGCs and other surrounding tissue showed a similar binding pattern, and (2) the staining in the PGCs was similar in the developmental stages studied. Labeling with Con A was due to Man, and not to Glc, as shown after incubation with glucose-oxidase, and it was assumed that Man was in N-linked oligosaccharides. However, GNA labeling was mainly due to O-linked oligosaccharides, because the pretreatment of beta-elimination turned cells negative. Moreover, acid hydrolysis pretreatment gave rise to a stronger GNA-staining, suggesting that either Man was also in subterminal position to NeuAc or some Man-containing glycans were unmasked after removal of NeuAc from other oligosaccharide chains.     

Construction of interval-valued fuzzy entropy invariant by translations and scalings

In this paper, we propose a method to construct interval-valued fuzzy entropies (Burillo and Bustince 1996). This method uses special aggregation functions applied to interval-contrasts. In this way, we are able to construct interval-valued fuzzy entropies from automorphisms and implication operators. Finally, we study the invariance of our constructions by scaling and translation.     

Functional dry fermented sausages manufactured with high levels of n‐3 fatty acids: nutritional benefits and evaluation of oxidation

Dry fermented sausages including fish oil extracts rich in n‐3 fatty acids were manufactured in order to obtain functional products, and their nutritional advantages and effects on oxidation process were compared with traditional ones. Modified products were manufactured with 5.3 g kg^?1 and 10.7 g kg^?1 of fish oil extract. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) contents per 100 g of dry fermented sausages were 0.15 g and 0.13 g for the lower rate of addition and 0.33 g and 0.26 g, respectively, for the higher rate, compared with only 0.01 g EPA and 0.03 g DHA in the control products. No significant differences were found in the other fatty acids. A decrease in the n‐6/n‐3 ratios from 16.14 in the control to 7.78 in batch A and 5.32 in batch B was achieved. Thiobarbituric acid reactive substances values were similar in control (0.31 ppm) and in batch A products (0.34 ppm) but increased significantly in batch B products (1.22 ppm). No statistical differences were observed among batches for the content of cholesterol oxidation products (2.36–2.43 µg g^?1 fat) leading to similar percentages of oxidation. 7‐Ketocholesterol, considered an indicator of oxidation, was not present in any sample. Values obtained for L* and hue (arctg b*/a*) were comparable with those of meat products. Although no effect was observed in cholesterol oxidation product formation and instrumental measurements of colour, the highest level of n‐3 fatty acid seemed to accelerate the oxidation process significantly. Copyright © 2004 Society of Chemical Industry     

Histochemical demonstration of two subtypes of O-linked oligosaccharides in the rat gastric glands

The gastric glands synthesize glycoproteins whose oligosaccharides are linked to the peptide core mainly by the O-glycosidic bond, specifically removed by beta-elimination procedure. Our aim was to research the possibility of the existence of two subtypes of O-linked oligosaccharides with a different behavior to the removal procedure. The lectins from peanut (PNA) and Maackia amurensis (MAA-I) were histochemically used as markers of the O-linked oligosaccharides. Sections were also pretreated with beta-elimination and/or peptide N-Glycosidase F (PNGase-F) for the specific removal of O- and N-linked oligosaccharides, respectively. The lectin GNA, which mainly labels to N-linked oligosaccharides, was used to test the correct working of PNGase-F. To test the possibility that the beta-elimination treatment could remove the terminal sialic acid residues, the lectin LFA was used. The surface epithelium was negative to PNA, while it became strongly positive when beta-elimination was performed for 1 day. This staining was resistant to PNGase-F, suggesting that PNA was labeling to O-linked oligosaccharides. However, after beta-elimination for 5 days this staining is not observed. A similar pattern appeared with MAA-I. We propose the existence of two subtypes of O-linked oligosaccharides: labile and resistant. The labile O-linked oligosaccharides are removed with beta-elimination for 1 day, unmasking the PNA-positive oligosaccharides. These oligosaccharides are resistant O-linked oligosaccharides because staining is abolished with longer treatment of beta-elimination. The results with MAA-I also support this suggestion. In summary, the labile O-linked oligosaccharides are removed with short treatment, while the resistant O-linked oligosaccharides need a stronger procedure (for 5 days).     

Conjugation of active iron superoxide dismutase to nanopatterned surfaces

Superoxide dismutase enzymes (SODs) are an essential part of the first line of cellular defense system against free radicals species. They catalyze the dismutation of superoxide radicals into oxygen and hydrogen peroxide. Although several studies have examined the attachment of superoxide dismutases to nanoparticles and nanostructures, never has been used a member of the Fe/MnSOD family. In this study, the behavior of plant origin FeSOD enzyme on three different nanopatterned surfaces was investigated as a function of covalent and electrostatic binding. Fluorescence microscopy was used to demonstrate that the protein is attached only to the gold layer. We also examined the activity of SOD by a colorimetric assay, and we have shown that the enzyme remains active after attachment to the three different surfaces under both kind of binding (electrostatic and covalent). This methodology could be useful for those who want to functionalize nanostructures with a SOD enzyme and test the activity. This process could be of great interest for the development of peroxynitrite and superoxide biosensors.     

Occurrence of ochratoxin A in Rioja Alavesa wines

In this survey the influence of the geographical location and the kind of wine in the concentration of ochratoxin A (OTA) was studied. Forty percent of the Spanish wine market belongs to the Rioja Qualified Designation of Origen (DOCa Rioja) wines, which are already worldwide known. A total of 100 wines from the Rioja Alavesa (RA) production area of the DOCa Rioja were analysed, using immunoaffinity column clean-up and high-performance liquid-chromatography with fluorimetric detection (detection limit 0.002 μg/l). The presence of OTA was greater in wines produced in low rainfall and high temperature regions. The geographical location and kind of wine did not seem to have influence on the OTA concentration.