J. Fernandez

A gravitational approach to edge detection based on triangular norms

We study the method of Sun et al. for edge detection based on the Law of Universal Gravity. We analyze the effect of the substitution of the product operation by other triangular norms in the calculation of the gravitational forces. We treat edges as fuzzy sets for which membership degrees are extracted from the resulting gravitational force on each pixel. We consider several prototypical triangular norms and experimentally show that their features determine the kind of edges detected. The new method is tested on the Berkeley Segmentation Dataset, showing to be competitive compared to the Canny method.

Comments on “Interval Type-2 Fuzzy Sets are Generalization of Interval-Valued Fuzzy Sets: Towards a Wide View on Their Relationship”

This letter makes some observations about “Interval type-2 fuzzy sets are generalization of interval-valued fuzzy sets: Towards a wide view on their relationship,” IEEE Trans. Fuzzy Systems that further support the distinction between an interval type-2 fuzzy set (IT2 FS) and an interval-valued fuzzy set (IV FS), points out that all operations, methods, and systems that have been developed and published about IT2 FSs are, so far, only valid in the special case when IT2 FS = IVFS, and suggests some research opportunities.

Aggregation for Atanassov’s Intuitionistic and Interval Valued Fuzzy Sets: The Median Operator

Atanassovs intuitionistic fuzzy sets (AIFS) and interval valued fuzzy sets (IVFS) are two generalizations of a fuzzy set, which are equivalent mathematically although different semantically. We analyze the median aggregation operator for AIFS and IVFS. Different mathematical theories have lead to different definitions of the median operator. We look at the median from various perspectives: as an instance of the intuitionistic ordered weighted averaging operator, as a Fermat point in a plane, as a minimizer of input disagreement, and as an operation on distributive lattices. We underline several connections between these approaches and summarize essential properties of the median in different representations.

Directional monotonicity of fusion functions

In this paper we deal with fusion functions, i.e., mappings from [0, 1]n into [0, 1]. As a generalization of the standard monotonicity and recently introduced weak monotonicity, we introduce and study the directional monotonicity of fusion functions. For distinguished fusion functions the sets of all directions in which they are increasing are determined. Moreover, in the paper the directional monotonicity of piecewise linear fusion functions is completely characterized. These results cover, among others, weighted arithmetic means, OWA operators, the Choquet, Sugeno and Shilkret integrals.

Role of sialic acid in acquired dysfibrinogenemia associated with liver cirrhosis

SummaryThe possible existence of acquired dysfibrinogenemia was investigated in blood samples from 30 patients with liver cirrhosis, 15 newborns and 30 healthy control subjects. Alterations of thrombin time were found in newborns and in 14 cirrhotic patients; glucide fraction levels were measured in these subjects and an increase in sialic acid content was observed. Its functional role was studied by comparing thrombin time and electrophoretic mobility of purified and desialylated forms of fibrinogen. We observed a thrombin time normalization, which was initially prolonged upon the removal of the sialic acid. The anodic electrophoretic mobility underwent changes due to the removal of sialic acid.

Evan’s Syndrome, Chronic Active Hepatitis and Focal Glomerulonephritis in IgA Deficiency

A 10-year-old female with a complete selective IgA deficiency and recurrent autoimmune disease (chronic active hepatitis, focal glomerulonephritis, hemolytic anemia and thrombopenic purpura) is presented. Both serum IgA and saliva secretory IgA were below the detection limit. The small bowel biopsy using a peroxidase-antiperoxidase technique showed absence of plasma cells secreting IgA. Circulating antibodies against mitochondria, microsomal thyroid antigen were detected as well as rheumatoid factor. Circulating immune complexes were present. A positive Coombs test and a slightly positive reaction for cryoagglutinins were demonstrated. No alterations in cellular immunity were observed. Clinical and analytical improvement with prednisone and azathioprine was obtained.

Theta-Fuzzy Associative Memories (Theta-FAMs)

Most fuzzy associative memories (FAMs) in the literature correspond to neural networks with a single layer of weights that distributively contains the information on associations to be stored. The main applications of these types of associative memory can be found in fuzzy rule-based systems. In contrast, Θ-fuzzy associative memories ( Θ-FAMs) represent parametrized fuzzy neural networks with a hidden layer and these FAM models extend (dual) S-FAMs and SM-FAMs based on fuzzy subsethood and similarity measures. In this paper, we provide theoretical results concerning the storage capacity and error correction capability of Θ-FAMs. In addition, we introduce a training algorithm for Θ-FAMs and we compare the error rates produced by Θ-FAMs and some well-known classifiers in some benchmark classification problems that are available on the internet. Finally, we apply Θ-FAMs to a problem of vision-based self-localization in mobile robotics.

Purification and characterization of a variant of human prothrombin : Prothrombin Segovia

A dysprothrombin designated prothrombin Segovia was isolated from the plasma of an individual with normal prothrombin antigen and prothrombin activity lesser than 25% of the control prothrombin activity. Activation by prothrombinase complex showed a lower amidolytic than clotting activity, which suggests a lesser generation of active intermediates than normal prothrombin. When prothrombin Segovia was activated by prothrombinase complex in the absence of factor Va, no thrombin formation was found by functional activities. SDS-PAGE analysis of the molecules derived by activation with prothrombinase complex, Taipan snake venom and Echis carinatus venom showed an accumulation of molecules not cleaved at bond Arg320-Ile321. This was more evident with Echis carinatus venom, which only acts on this bond. Our data suggest that the alteration of prothrombin Segovia impairs the scission of bond Arg320-Ile321.

Congenital dysfibrinogenemias. A review

SummaryInherited qualitative abnormalities of fibrinogen have been documented in 144 families. These dysfibrinogenemias have been inherited as autosomal dominant traits and usually are clinically silent, but in some cases are associated with bleeding, thrombosis, or defective wound healing. Dysfibrinogenemias may be associated with defects in any of the three basic steps in the thrombin-fibrinogen reaction, i.e., cleavage of the fibrinopeptides by thrombin, polymerization, and fibrin cross-linking. Biochemical studies of several abnormal fibrinogens have demonstrated that the functional defects are the result of single amino acid substitutions. Most of the reported cases may be distinguished by functional criteria and by the physicochemical behavior and biochemical nature of the abnormal protein.

Upper bounding overlaps by groupings

The notions of overlapping and grouping arise from the problem how to assign an object to exactly one class among several available. In this respect, overlaps and groupings are connected with t-norms and t-conorms. However, there are some properties of t-norms and t-conorms that are not valid for overlaps and groupings, for example, that any t-norm is less than or equal than any t-conorm. This fact motivates the proposed research. Specifically, we determine conditions to ensure that an overlap is smaller than a certain grouping and methods to define operators satisfying such ordering. The relevance of this study is visible at the end of the paper by the inclusion of an illustrative example in the context of image processing.