87,816 research outputs found
A ROC-based Reject Rule for Dichotomizers
No full textMany complex classification tasks involve a discrimination between two classes. Since in such cases a classification error could frequently have serious consequences, the classifiers employed should ensure a very high reliability to avoid erroneous decisions. Unfortunately this is difficult to obtain in real situations where the classifier can meet samples very different from those examined in the training phase. Moreover, the cost for a wrong classification can be so high that it is convenient to reject the sample which gives raise to an unreliable result. However, despite its relevance, a reject option specifically devised for dichotomizers (i.e. two-class classifiers) has not been yet proposed. This paper presents a novel reject rule for dichotomizers, based on the Receiver Operating Characteristic curve. The rule minimizes the expected classification cost, defined on the basis of classification and error costs peculiar for the application at hand. Experiments performed with different classifier architectures on several data sets publicly available confirmed the effectiveness of the proposed reject rule
Reducing the Classification Cost of Support Vector Classifiers through a ROC-based Reject Rule
No full textThis paper presents a novel reject rule for support vector classifiers, based on the receiver operating characteristic (ROC) curve. The rule minimises the expected classification cost, defined on the basis of classification and the error costs for the particular application at hand. The rationale of the proposed approach is that the ROC curve of the SVM contains all of the necessary information to find the optimal threshold values that minimise the expected classification cost. To evaluate the effectiveness of the proposed reject rule, a large number of tests has been performed on several data sets, and with different kernels. A comparison technique, based on the Wilcoxon rank sum test, has been defined and employed to provide the results at an adequate significance level. The experiments have definitely confirmed the effectiveness of the proposed reject rule
A ROC-based Reject Rule for Support Vector Machines
No full textThis paper presents a novel reject rule for SVM classifiers, based on the Receiver Operating Characteristic curve. The rule minimizes the expected classification cost, defined on the basis of classification and error costs peculiar for the application at hand. Experiments performed with different kernels on several data sets publicly available confirmed the effectiveness of the proposed reject rule
Analisi delle caratteristiche audiologiche e delle comorbidità in pazienti con acufene cronico
No full textA role for the TIM-3/GAL-9/BAT3 pathway in determining the clinical phenotype of multiple sclerosis
No full textT-cell immunoglobulin and mucin domain 3 (Tim-3) ligates galectin-9 (Gal-9); this process, resulting in the inhibition of Th1 responses and in the apoptosis of antigen-specific cells, is hampered by binding of the molecular adaptor human leukocyte antigen B (HLA-B)-associated transcript 3 (Bat3) to the intracellular tail of Tim-3. Apoptosis of myelin basic protein (MBP)-specific T lymphocytes correlates with reduced rates of disease progression in multiple sclerosis (MS). We extensively analyzed the Tim-3/Gal-9/Bat3 pathway in 87 patients with a diagnosis of stable relapsing-remitting MS (RRMS), primary progressive MS (PPMS), or benign MS (BEMS), as well as in 40 healthy control (HC) subjects. Results showed that MBP-specific CD4(+)Tim-3(+), CD4(+)/Gal-9(+), and CD4(+)/Tim-3(+)/AV(+) (apoptotic) T lymphocytes were augmented in the BEMS group, whereas CD4(+)/Bat3(+) and CD8(+)/Bat3(+) T lymphocytes were increased and CD4(+)/Tim-3(+)/AV(+) T cells were reduced in the PPMS group (>2 fold and P<0.05 in all cases). Blocking the Tim-3/Gal-9 interaction with specific mAb reduced T-lymphocyte apoptosis and augmented production of IFNγ and IL-17 in the BEMS, RRMS, and HC groups, but not in the PPMS group. The Tim-3/Gal-9 interaction favors apoptosis of MBP-specific T lymphocytes in BEMS; this process is reduced in PPMS by the up-regulation of Bat3. Therapeutic interventions aimed at silencing Bat3 could be beneficial in MS.-Saresella, M., Piancone, F., Marventano, I., La Rosa, F., Tortorella, P., Caputo, D., Rovaris, M., Clerici, M. A role for the TIM-3/GAL-9/BAT3 pathway in determining the clinical phenotype of multiple sclerosis
An Optimal Reject Rule for Binary Classifiers
No full textBinary classifiers are used in many complex classification problems in which the classification result could have serious consequences. Thus, they should ensure a very high reliability to avoid erroneous decisions. Unfortunately, this is rarely the case in real situations where the cost for a wrong classification could be so high that it should be convenient to reject the sample which gives raise to an unreliable result. However, as far as we know, a reject option specifically devised for binary classifiers has not been yet proposed. This paper presents an optimal reject rule for binary classifiers, based on the Receiver Operating Characteristic curve. The rule is optimal since it maximizes a classification utility function, defined on the basis of classification and error costs peculiar for the application at hand. Experiments performed with a data set publicly available confirmed the effectiveness of the proposed reject rule
Parution : "Les Equivoques de l'institution. Normes, individu et pouvoir", dirigé par Elodie Djordjevic, Sabina Tortorella et Mathilde Unger
No full textL'ouvrage collectif "Les Equivoques de l'institution. Normes, individu et pouvoir", dirigé par Elodie Djordjevic, Sabina Tortorella et Mathilde Unger, vient de paraître chez Classiques Garnier. Avec des contributions de O. Beaud, J. Couillerot, V. Descombes, E. Djordjevic, Th. Guilluy, J.-F. Kervégan, P. Napoli, M. Plouviez, T. Pouthier, Ph. Raynaud, J.-M. Roux, Fr. Saint-Bonnet, S. Tortorella, M. Unger. Résumé : Cet ouvrage présente les équivoques de l’institution et met à l’épreuve la conce..
Exploiting coding theory for classification: An LDPC-based strategy for multiclass-to-binary decomposition
No full textA powerful strategy for the classification of multiple classes is to create a classifier ensemble that decomposes the polychotomy into several dichotomies. The central issue when designing a multiclass-to-binary decomposition scheme is the definition of both the coding matrix and the decoding algorithm. In this study, we propose a new classification system based on low-density parity-check codes, which is a very effective class of binary block codes. The main idea is to exploit the algebraic properties of the codes to generate the codewords for the coding matrix and to define two decoding approaches, which allow us to detect and recover possible errors or rejects produced by the dichotomizers. Experiments based on benchmark datasets demonstrated that the proposed approach provides a statistically significant improvement in terms of the classification performance compared with state-of-the-art decomposition strategies
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