Financial distress prediction using the hybrid associative memory with translation

This paper presents an alternative technique for financial distress prediction systems. The method is based on a type of neural network, which is called hybrid associative memory with translation. While many different neural network architectures have successfully been used to predict credit risk and corporate failure, the power of associative memories for financial decision-making has not been explored in any depth as yet. The performance of the hybrid associative memory with translation is compared to four traditional neural networks, a support vector machine and a logistic regression model in terms of their prediction capabilities. The experimental results over nine real-life data sets show that the associative memory here proposed constitutes an appropriate solution for bankruptcy and credit risk prediction, performing significantly better than the rest of models under class imbalance and data overlapping conditions in terms of the true positive rate and the geometric mean of true positive and true negative rates.This work has partially been supported by the Mexican CONACYT through the Postdoctoral Fellowship Program [232167], the Spanish Ministry of Economy [TIN2013-46522-P], the Generalitat Valenciana [PROMETEOII/2014/062] and the Mexican PRODEP [DSA/103.5/15/7004]. We would like to thank the Reviewers for their valuable comments and suggestions, which have helped to improve the quality of this paper substantially

Associative learning on imbalanced environments: An empirical study

Associative memories have emerged as a powerful computational neural network model for several pattern classification problems. Like most traditional classifiers, these models assume that the classes share similar prior probabilities. However, in many real-life applications the ratios of prior probabilities between classes are extremely skewed. Although the literature has provided numerous studies that examine the performance degradation of renowned classifiers on different imbalanced scenarios, so far this effect has not been supported by a thorough empirical study in the context of associative memories. In this paper, we fix our attention on the applicability of the associative neural networks to the classification of imbalanced data. The key questions here addressed are whether these models perform better, the same or worse than other popular classifiers, how the level of imbalance affects their performance, and whether distinct resampling strategies produce a different impact on the associative memories. In order to answer these questions and gain further insight into the feasibility and efficiency of the associative memories, a large-scale experimental evaluation with 31 databases, seven classification models and four resampling algorithms is carried out here, along with a non-parametric statistical test to discover any significant differences between each pair of classifiers.This work has partially been supported by the Mexican Science and Technology Council (CONACYT-Mexico) through the Postdoctoral Fellowship Program (232167), the Mexican PRODEP(DSA/103.5/15/7004), the Spanish Ministry of Economy(TIN2013-46522-P) and the Generalitat Valenciana (PROMETEOII/2014/062)

Hierarchically Clustered Adaptive Quantization CMAC and Its Learning Convergence

No abstract availabl

A Survey of Adaptive Resonance Theory Neural Network Models for Engineering Applications

This survey samples from the ever-growing family of adaptive resonance theory (ART) neural network models used to perform the three primary machine learning modalities, namely, unsupervised, supervised and reinforcement learning. It comprises a representative list from classic to modern ART models, thereby painting a general picture of the architectures developed by researchers over the past 30 years. The learning dynamics of these ART models are briefly described, and their distinctive characteristics such as code representation, long-term memory and corresponding geometric interpretation are discussed. Useful engineering properties of ART (speed, configurability, explainability, parallelization and hardware implementation) are examined along with current challenges. Finally, a compilation of online software libraries is provided. It is expected that this overview will be helpful to new and seasoned ART researchers

Exponential fuzzy associative memories with application in classification

Orientador: Marcos Eduardo Ribeiro do Valle MesquitaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática Estatística e Computação CientíficaResumo: Memórias associativas são modelos matemáticos cujo principal objetivo é armazenar e recuperar informação por associação. Tais modelos são projetados para armazenar um conjunto finito de pares, chamado conjunto das memórias fundamentais, e devem apresentar certa tolerância a ruído, isto é, serem capazes de recuperar uma certa informação armazenada mesmo a partir de uma versão incompleta ou corrompida de um item memorizado. As memórias associativas recorrentes por correlação (RCAMs, do inglês Recurrent Correlation Associative Memories), introduzidas por Chiueh e Goodman, apresentam grande capacidade de armazenamento e excelente tolerância a ruído. Todavia, as RCAMs são projetadas para armazenar e recuperar padrões bipolares. As memórias associativas recorrentes exponenciais fuzzy generalizadas (GRE-FAMs, do inglês Generalized Recurrent Exponential Fuzzy Associative Memories) podem ser vistas como uma versão generalizada das RCAMs capazes de armazenar e recuperar conjuntos fuzzy. Nesta tese, introduzimos as memórias associativas bidirecionais exponenciais fuzzy generalizadas (GEB-FAMs, do inglês Generalized Exponential Bidirectional Fuzzy Associative Memories), uma extensão das GRE-FAMs para o caso heteroassociativo. Uma vez que as GEB-FAMs são baseadas em uma medida de similaridade, realizamos um estudo de diversas medidas de similaridade da literatura, dentre elas as medidas de similaridade baseadas em cardinalidade e a medida de similaridade estrutural (SSIM). Além disso, mostramos que as GEB-FAMs exibem ótima capacidade de armazenamento e apresentamos uma caracterização da saída de um passo das GEB-FAMs quando um dos seus parâmetros tende a infinito. No entanto, em experimentos computacionais, bons resultados foram obtidos por um único passo da GEB-FAM com valores do parâmetro no intervalo [1,10]. Como a dinâmica das GEB-FAMs ainda não está totalmente compreendida, este fato motivou um estudo mais aprofundado das GEB-FAMs de passo único, modelos denominados memórias associativas fuzzy com núcleo (fuzzy-KAM, do inglês fuzzy Kernel Associative Memories). Interpretamos este modelo utilizando um núcleo fuzzy e propomos ajustar seu parâmetro utilizando o conceito de entropia. Apresentamos também duas abordagens para classificação de padrões usando as fuzzy-KAMs. Finalmente, descrevemos os experimentos computacionais realizados para avaliar o desempenho de tais abordagens em problemas de classificação e reconhecimento de faces. Na maioria dos experimentos realizados, em ambos os tipos de problemas, os classificadores definidos com base nas abordagens propostas obtiveram desempenho satisfatório e competitivo com os obtidos por outros modelos da literatura, o que mostra a versatilidade de tais abordagensAbstract: Associative memories are mathematical models whose main objective is to store and recall information by association. Such models are designed for the storage a finite set of pairs, called fundamental memory set, and they must present certain noise tolerance, that is, they should be able to retrieve a stored information even from an incomplete or corrupted version of a memorized item. The recurrent correlation associative memories (RCAMs), introduced by Chiueh and Goodman, present large storage capacity and excellent noise tolerance. However, RCAMs are designed to store and retrieve bipolar patterns. The generalized recurrent exponential fuzzy associative memories (GRE-FAMs) can be seen as a generalized version of RCAMs capable of storing and retrieving fuzzy sets. In this thesis, we introduce the generalized exponential bidirectional fuzzy associative memories (GEB-FAMs), an extension of GRE-FAMs to the heteroassociative case. Since GEB-FAMs are based on a similarity measure, we conducted a study of several measures from the literature, including the cardinality based similarity measure and the structural similarity index (SSIM). Furthermore, we show that GEB-FAMs exhibit optimal storage capacity and we present a characterization of the output of a single-step GEB-FAM when one of its parameters tends to infinity. However, in computational experiments, good results were obtained by a single-step GEB-FAM with parameter values in the interval [1,10]. As the dynamics of the GEB-FAMs is still not fully understood, this fact led to a more detailed study of the single-step GEB-FAMs, refered to as fuzzy kernel associative memories (fuzzy-KAMs). We interpret this model by using a fuzzy kernel and we propose to adjust its parameter by using the concept of entropy. Also, we present two approaches to pattern classification using the fuzzy-KAMs. Finally, we describe computational experiments used to evaluate the performance of such approaches in classification and face recognition problems. In most of the experiments performed, in both types of problems, the classifiers defined based on the proposed approaches obtained satisfactory and competitive performance with those obtained by other models from the literature, which shows the versatility of such approachesDoutoradoMatematica AplicadaDoutora em Matemática Aplicada2015/00745-1CAPESFAPES